Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

288 files changed, 100770 insertions, 0 deletions

diff --git a/src/VBox/Runtime/r3/Makefile.kup b/src/VBox/Runtime/r3/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/Makefile.kup
diff --git a/src/VBox/Runtime/r3/RTPathTemp.cpp b/src/VBox/Runtime/r3/RTPathTemp.cpp
new file mode 100644
index 00000000..dc43a612
--- /dev/null
+++ b/src/VBox/Runtime/r3/RTPathTemp.cpp
@@ -0,0 +1,86 @@
+/* $Id: RTPathTemp.cpp $ */
+/** @file
+ * IPRT - Path Manipulation, RTPathTemp.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/path.h>
+
+#include <iprt/assert.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include "internal/path.h"
+
+
+RTDECL(int) RTPathTemp(char *pszPath, size_t cchPath)
+{
+    /*
+     * Try get it from the environment first.
+     */
+    static const char * const s_apszVars[] =
+    {
+        "IPRT_TMPDIR"
+#if defined(RT_OS_WINDOWS)
+        , "TMP", "TEMP", "USERPROFILE"
+#elif defined(RT_OS_OS2)
+        , "TMP", "TEMP", "TMPDIR"
+#else
+        , "TMPDIR"
+#endif
+    };
+    for (size_t iVar = 0; iVar < RT_ELEMENTS(s_apszVars); iVar++)
+    {
+        int rc = RTEnvGetEx(RTENV_DEFAULT, s_apszVars[iVar], pszPath, cchPath, NULL);
+        if (rc != VERR_ENV_VAR_NOT_FOUND)
+            return rc;
+    }
+
+    /*
+     * Here we should use some sane system default, instead we just use
+     * the typical unix temp dir for now.
+     */
+    /** @todo Windows should default to the windows directory, see GetTempPath.
+     * Some unixes has path.h and _PATH_TMP. There is also a question about
+     * whether /var/tmp wouldn't be a better place...  */
+    if (cchPath < sizeof("/tmp") )
+        return VERR_BUFFER_OVERFLOW;
+    memcpy(pszPath, "/tmp", sizeof("/tmp"));
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/alloc-ef-cpp.cpp b/src/VBox/Runtime/r3/alloc-ef-cpp.cpp
new file mode 100644
index 00000000..b9496caa
--- /dev/null
+++ b/src/VBox/Runtime/r3/alloc-ef-cpp.cpp
@@ -0,0 +1,169 @@
+/* $Id: alloc-ef-cpp.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, C++ electric fence.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "alloc-ef.h"
+
+#include <iprt/asm.h>
+#include <new>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @todo test this on MSC */
+
+/** MSC declares the operators as cdecl it seems. */
+#ifdef _MSC_VER
+# define RT_EF_CDECL    __cdecl
+#else
+# define RT_EF_CDECL
+#endif
+
+/** MSC doesn't use the standard namespace. */
+#ifdef _MSC_VER
+# define RT_EF_SIZE_T   size_t
+#else
+# define RT_EF_SIZE_T   std::size_t
+#endif
+
+/** The hint that we're throwing std::bad_alloc is not apprecitated by MSC. */
+#ifdef RT_EXCEPTIONS_ENABLED
+# ifdef _MSC_VER
+#  define RT_EF_THROWS_BAD_ALLOC
+#  define RT_EF_NOTHROW               RT_NO_THROW_DEF
+# else
+#  ifdef _GLIBCXX_THROW
+#   define RT_EF_THROWS_BAD_ALLOC     _GLIBCXX_THROW(std::bad_alloc)
+#  elif defined(__cplusplus) && (__cplusplus + 0) < 201700
+#   define RT_EF_THROWS_BAD_ALLOC     throw(std::bad_alloc)
+#  else
+#   define RT_EF_THROWS_BAD_ALLOC     noexcept(false)
+#  endif
+#  define RT_EF_NOTHROW               throw()
+# endif
+#else  /* !RT_EXCEPTIONS_ENABLED */
+# define RT_EF_THROWS_BAD_ALLOC
+# define RT_EF_NOTHROW
+#endif /* !RT_EXCEPTIONS_ENABLED */
+
+
+void *RT_EF_CDECL operator new(RT_EF_SIZE_T cb) RT_EF_THROWS_BAD_ALLOC
+{
+    void *pv = rtR3MemAlloc("new", RTMEMTYPE_NEW, cb, cb, NULL, ASMReturnAddress(), NULL, 0, NULL);
+    if (!pv)
+        throw std::bad_alloc();
+    return pv;
+}
+
+
+void *RT_EF_CDECL operator new(RT_EF_SIZE_T cb, const std::nothrow_t &) RT_EF_NOTHROW
+{
+    void *pv = rtR3MemAlloc("new nothrow", RTMEMTYPE_NEW, cb, cb, NULL, ASMReturnAddress(), NULL, 0, NULL);
+    return pv;
+}
+
+
+void RT_EF_CDECL operator delete(void *pv) RT_EF_NOTHROW
+{
+    rtR3MemFree("delete", RTMEMTYPE_DELETE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+#ifdef __cpp_sized_deallocation
+void RT_EF_CDECL operator delete(void *pv, RT_EF_SIZE_T cb) RT_EF_NOTHROW
+{
+    NOREF(cb);
+    AssertMsgFailed(("cb ignored!\n"));
+    rtR3MemFree("delete", RTMEMTYPE_DELETE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+#endif
+
+
+void RT_EF_CDECL operator delete(void * pv, const std::nothrow_t &) RT_EF_NOTHROW
+{
+    rtR3MemFree("delete nothrow", RTMEMTYPE_DELETE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+/*
+ *
+ * Array object form.
+ * Array object form.
+ * Array object form.
+ *
+ */
+
+void *RT_EF_CDECL operator new[](RT_EF_SIZE_T cb) RT_EF_THROWS_BAD_ALLOC
+{
+    void *pv = rtR3MemAlloc("new[]", RTMEMTYPE_NEW_ARRAY, cb, cb, NULL, ASMReturnAddress(), NULL, 0, NULL);
+    if (!pv)
+        throw std::bad_alloc();
+    return pv;
+}
+
+
+void * RT_EF_CDECL operator new[](RT_EF_SIZE_T cb, const std::nothrow_t &) RT_EF_NOTHROW
+{
+    void *pv = rtR3MemAlloc("new[] nothrow", RTMEMTYPE_NEW_ARRAY, cb, cb, NULL, ASMReturnAddress(), NULL, 0, NULL);
+    return pv;
+}
+
+
+void RT_EF_CDECL operator delete[](void * pv) RT_EF_NOTHROW
+{
+    rtR3MemFree("delete[]", RTMEMTYPE_DELETE_ARRAY, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+#ifdef __cpp_sized_deallocation
+void RT_EF_CDECL operator delete[](void * pv, RT_EF_SIZE_T cb) RT_EF_NOTHROW
+{
+    NOREF(cb);
+    AssertMsgFailed(("cb ignored!\n"));
+    rtR3MemFree("delete[]", RTMEMTYPE_DELETE_ARRAY, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+#endif
+
+
+void RT_EF_CDECL operator delete[](void *pv, const std::nothrow_t &) RT_EF_NOTHROW
+{
+    rtR3MemFree("delete[] nothrow", RTMEMTYPE_DELETE_ARRAY, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
diff --git a/src/VBox/Runtime/r3/alloc-ef.cpp b/src/VBox/Runtime/r3/alloc-ef.cpp
new file mode 100644
index 00000000..4b61d906
--- /dev/null
+++ b/src/VBox/Runtime/r3/alloc-ef.cpp
@@ -0,0 +1,1088 @@
+/* $Id: alloc-ef.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, electric fence.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "alloc-ef.h"
+#include <iprt/mem.h>
+#include <iprt/log.h>
+#include <iprt/asm.h>
+#include <iprt/thread.h>
+#include <VBox/sup.h>
+#include <iprt/errcore.h>
+#ifndef IPRT_NO_CRT
+# include <errno.h>
+# include <stdio.h>
+# include <stdlib.h>
+#endif
+
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+
+#ifdef RTALLOC_REPLACE_MALLOC
+# include <VBox/dis.h>
+# include <VBox/disopcode.h>
+# include <dlfcn.h>
+# ifdef RT_OS_DARWIN
+#  include <malloc/malloc.h>
+# endif
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RTALLOC_REPLACE_MALLOC
+# define RTMEM_REPLACMENT_ALIGN(a_cb) ((a_cb) >= 16 ? RT_ALIGN_Z(a_cb, 16) \
+                                       : (a_cb) >= sizeof(uintptr_t) ? RT_ALIGN_Z(a_cb,  sizeof(uintptr_t)) : (a_cb))
+#endif
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#ifdef RTALLOC_EFENCE_TRACE
+/** Spinlock protecting the all the block's globals. */
+static volatile uint32_t    g_BlocksLock;
+/** Tree tracking the allocations. */
+static AVLPVTREE            g_BlocksTree;
+# ifdef RTALLOC_EFENCE_FREE_DELAYED
+/** Tail of the delayed blocks. */
+static volatile PRTMEMBLOCK g_pBlocksDelayHead;
+/** Tail of the delayed blocks. */
+static volatile PRTMEMBLOCK g_pBlocksDelayTail;
+/** Number of bytes in the delay list (includes fences). */
+static volatile size_t      g_cbBlocksDelay;
+# endif /* RTALLOC_EFENCE_FREE_DELAYED */
+# ifdef RTALLOC_REPLACE_MALLOC
+/** @name For calling the real allocation API we've replaced.
+ * @{ */
+void * (*g_pfnOrgMalloc)(size_t);
+void * (*g_pfnOrgCalloc)(size_t, size_t);
+void * (*g_pfnOrgRealloc)(void *, size_t);
+void   (*g_pfnOrgFree)(void *);
+size_t (*g_pfnOrgMallocSize)(void *);
+/** @} */
+# endif
+#endif /* RTALLOC_EFENCE_TRACE */
+/** Array of pointers free watches for. */
+void   *gapvRTMemFreeWatch[4] = {NULL, NULL, NULL, NULL};
+/** Enable logging of all freed memory. */
+bool    gfRTMemFreeLog = false;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+#ifdef RTALLOC_REPLACE_MALLOC
+static void rtMemReplaceMallocAndFriends(void);
+#endif
+
+
+/**
+ * Complains about something.
+ */
+static void rtmemComplain(const char *pszOp, const char *pszFormat, ...)
+{
+    va_list args;
+    fprintf(stderr, "RTMem error: %s: ", pszOp);
+    va_start(args, pszFormat);
+    vfprintf(stderr, pszFormat, args);
+    va_end(args);
+    RTAssertDoPanic();
+}
+
+/**
+ * Log an event.
+ */
+DECLINLINE(void) rtmemLog(const char *pszOp, const char *pszFormat, ...)
+{
+#if 0
+    va_list args;
+    fprintf(stderr, "RTMem info: %s: ", pszOp);
+    va_start(args, pszFormat);
+    vfprintf(stderr, pszFormat, args);
+    va_end(args);
+#else
+    NOREF(pszOp); NOREF(pszFormat);
+#endif
+}
+
+
+#ifdef RTALLOC_EFENCE_TRACE
+
+/**
+ * Acquires the lock.
+ */
+DECLINLINE(void) rtmemBlockLock(void)
+{
+    unsigned c = 0;
+    while (!ASMAtomicCmpXchgU32(&g_BlocksLock, 1, 0))
+        RTThreadSleepNoLog(((++c) >> 2) & 31);
+}
+
+
+/**
+ * Releases the lock.
+ */
+DECLINLINE(void) rtmemBlockUnlock(void)
+{
+    Assert(g_BlocksLock == 1);
+    ASMAtomicXchgU32(&g_BlocksLock, 0);
+}
+
+
+/**
+ * Creates a block.
+ */
+DECLINLINE(PRTMEMBLOCK) rtmemBlockCreate(RTMEMTYPE enmType, size_t cbUnaligned, size_t cbAligned,
+                                         const char *pszTag, void *pvCaller, RT_SRC_POS_DECL)
+{
+# ifdef RTALLOC_REPLACE_MALLOC
+    if (!g_pfnOrgMalloc)
+        rtMemReplaceMallocAndFriends();
+    PRTMEMBLOCK pBlock = (PRTMEMBLOCK)g_pfnOrgMalloc(sizeof(*pBlock));
+# else
+    PRTMEMBLOCK pBlock = (PRTMEMBLOCK)malloc(sizeof(*pBlock));
+# endif
+    if (pBlock)
+    {
+        pBlock->enmType     = enmType;
+        pBlock->cbUnaligned = cbUnaligned;
+        pBlock->cbAligned   = cbAligned;
+        pBlock->pszTag      = pszTag;
+        pBlock->pvCaller    = pvCaller;
+        pBlock->iLine       = iLine;
+        pBlock->pszFile     = pszFile;
+        pBlock->pszFunction = pszFunction;
+    }
+    return pBlock;
+}
+
+
+/**
+ * Frees a block.
+ */
+DECLINLINE(void) rtmemBlockFree(PRTMEMBLOCK pBlock)
+{
+# ifdef RTALLOC_REPLACE_MALLOC
+    g_pfnOrgFree(pBlock);
+# else
+    free(pBlock);
+# endif
+}
+
+
+/**
+ * Insert a block from the tree.
+ */
+DECLINLINE(void) rtmemBlockInsert(PRTMEMBLOCK pBlock, void *pv)
+{
+    pBlock->Core.Key = pv;
+    rtmemBlockLock();
+    bool fRc = RTAvlPVInsert(&g_BlocksTree, &pBlock->Core);
+    rtmemBlockUnlock();
+    AssertRelease(fRc);
+}
+
+
+/**
+ * Remove a block from the tree and returns it to the caller.
+ */
+DECLINLINE(PRTMEMBLOCK) rtmemBlockRemove(void *pv)
+{
+    rtmemBlockLock();
+    PRTMEMBLOCK pBlock = (PRTMEMBLOCK)RTAvlPVRemove(&g_BlocksTree, pv);
+    rtmemBlockUnlock();
+    return pBlock;
+}
+
+/**
+ * Gets a block.
+ */
+DECLINLINE(PRTMEMBLOCK) rtmemBlockGet(void *pv)
+{
+    rtmemBlockLock();
+    PRTMEMBLOCK pBlock = (PRTMEMBLOCK)RTAvlPVGet(&g_BlocksTree, pv);
+    rtmemBlockUnlock();
+    return pBlock;
+}
+
+/**
+ * Dumps one allocation.
+ */
+static DECLCALLBACK(int) RTMemDumpOne(PAVLPVNODECORE pNode, void *pvUser)
+{
+    PRTMEMBLOCK pBlock = (PRTMEMBLOCK)pNode;
+    fprintf(stderr, "%p %08lx(+%02lx) %p\n",
+            pBlock->Core.Key,
+            (unsigned long)pBlock->cbUnaligned,
+            (unsigned long)(pBlock->cbAligned - pBlock->cbUnaligned),
+            pBlock->pvCaller);
+    NOREF(pvUser);
+    return 0;
+}
+
+/**
+ * Dumps the allocated blocks.
+ * This is something which you should call from gdb.
+ */
+extern "C" void RTMemDump(void);
+void RTMemDump(void)
+{
+    fprintf(stderr, "address  size(alg)     caller\n");
+    RTAvlPVDoWithAll(&g_BlocksTree, true, RTMemDumpOne, NULL);
+}
+
+# ifdef RTALLOC_EFENCE_FREE_DELAYED
+
+/**
+ * Insert a delayed block.
+ */
+DECLINLINE(void) rtmemBlockDelayInsert(PRTMEMBLOCK pBlock)
+{
+    size_t cbBlock = RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE;
+    pBlock->Core.pRight = NULL;
+    pBlock->Core.pLeft = NULL;
+    rtmemBlockLock();
+    if (g_pBlocksDelayHead)
+    {
+        g_pBlocksDelayHead->Core.pLeft = (PAVLPVNODECORE)pBlock;
+        pBlock->Core.pRight = (PAVLPVNODECORE)g_pBlocksDelayHead;
+        g_pBlocksDelayHead = pBlock;
+    }
+    else
+    {
+        g_pBlocksDelayTail = pBlock;
+        g_pBlocksDelayHead = pBlock;
+    }
+    g_cbBlocksDelay += cbBlock;
+    rtmemBlockUnlock();
+}
+
+/**
+ * Removes a delayed block.
+ */
+DECLINLINE(PRTMEMBLOCK) rtmemBlockDelayRemove(void)
+{
+    PRTMEMBLOCK pBlock = NULL;
+    rtmemBlockLock();
+    if (g_cbBlocksDelay > RTALLOC_EFENCE_FREE_DELAYED)
+    {
+        pBlock = g_pBlocksDelayTail;
+        if (pBlock)
+        {
+            g_pBlocksDelayTail = (PRTMEMBLOCK)pBlock->Core.pLeft;
+            if (pBlock->Core.pLeft)
+                pBlock->Core.pLeft->pRight = NULL;
+            else
+                g_pBlocksDelayHead = NULL;
+            g_cbBlocksDelay -= RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE;
+        }
+    }
+    rtmemBlockUnlock();
+    return pBlock;
+}
+
+
+/**
+ * Dumps the freed blocks.
+ * This is something which you should call from gdb.
+ */
+extern "C" void RTMemDumpFreed(void);
+void RTMemDumpFreed(void)
+{
+    fprintf(stderr, "address  size(alg)     caller\n");
+    for (PRTMEMBLOCK pCur = g_pBlocksDelayHead; pCur; pCur = (PRTMEMBLOCK)pCur->Core.pRight)
+        RTMemDumpOne(&pCur->Core, NULL);
+
+}
+
+# endif  /* RTALLOC_EFENCE_FREE_DELAYED */
+
+#endif /* RTALLOC_EFENCE_TRACE */
+
+
+#if defined(RTALLOC_REPLACE_MALLOC) && defined(RTALLOC_EFENCE_TRACE)
+/*
+ *
+ * Replacing malloc, calloc, realloc, & free.
+ *
+ */
+
+/** Replacement for malloc. */
+static void *rtMemReplacementMalloc(size_t cb)
+{
+    size_t cbAligned = RTMEM_REPLACMENT_ALIGN(cb);
+    void *pv = rtR3MemAlloc("r-malloc", RTMEMTYPE_RTMEMALLOC, cb, cbAligned, "heap", ASMReturnAddress(), RT_SRC_POS);
+    if (!pv)
+        pv = g_pfnOrgMalloc(cb);
+    return pv;
+}
+
+/** Replacement for calloc. */
+static void *rtMemReplacementCalloc(size_t cbItem, size_t cItems)
+{
+    size_t cb = cbItem * cItems;
+    size_t cbAligned = RTMEM_REPLACMENT_ALIGN(cb);
+    void *pv = rtR3MemAlloc("r-calloc", RTMEMTYPE_RTMEMALLOCZ, cb, cbAligned, "heap", ASMReturnAddress(), RT_SRC_POS);
+    if (!pv)
+        pv = g_pfnOrgCalloc(cbItem, cItems);
+    return pv;
+}
+
+/** Replacement for realloc. */
+static void *rtMemReplacementRealloc(void *pvOld, size_t cbNew)
+{
+    if (pvOld)
+    {
+        /* We're not strict about where the memory was allocated. */
+        PRTMEMBLOCK pBlock = rtmemBlockGet(pvOld);
+        if (pBlock)
+        {
+            size_t cbAligned = RTMEM_REPLACMENT_ALIGN(cbNew);
+            return rtR3MemRealloc("r-realloc", RTMEMTYPE_RTMEMREALLOC, pvOld, cbAligned, "heap", ASMReturnAddress(), RT_SRC_POS);
+        }
+        return g_pfnOrgRealloc(pvOld, cbNew);
+    }
+    return rtMemReplacementMalloc(cbNew);
+}
+
+/** Replacement for free(). */
+static void rtMemReplacementFree(void *pv)
+{
+    if (pv)
+    {
+        /* We're not strict about where the memory was allocated. */
+        PRTMEMBLOCK pBlock = rtmemBlockGet(pv);
+        if (pBlock)
+            rtR3MemFree("r-free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), RT_SRC_POS);
+        else
+            g_pfnOrgFree(pv);
+    }
+}
+
+# ifdef RT_OS_DARWIN
+/** Replacement for malloc. */
+static size_t rtMemReplacementMallocSize(void *pv)
+{
+    size_t cb;
+    if (pv)
+    {
+        /* We're not strict about where the memory was allocated. */
+        PRTMEMBLOCK pBlock = rtmemBlockGet(pv);
+        if (pBlock)
+            cb = pBlock->cbUnaligned;
+        else
+            cb = g_pfnOrgMallocSize(pv);
+    }
+    else
+        cb = 0;
+    return cb;
+}
+# endif
+
+
+static void rtMemReplaceMallocAndFriends(void)
+{
+    struct
+    {
+        const char *pszName;
+        PFNRT       pfnReplacement;
+        PFNRT       pfnOrg;
+        PFNRT      *ppfnJumpBack;
+    } aApis[] =
+    {
+        { "free",    (PFNRT)rtMemReplacementFree,    (PFNRT)free,    (PFNRT *)&g_pfnOrgFree },
+        { "realloc", (PFNRT)rtMemReplacementRealloc, (PFNRT)realloc, (PFNRT *)&g_pfnOrgRealloc },
+        { "calloc",  (PFNRT)rtMemReplacementCalloc,  (PFNRT)calloc,  (PFNRT *)&g_pfnOrgCalloc },
+        { "malloc",  (PFNRT)rtMemReplacementMalloc,  (PFNRT)malloc,  (PFNRT *)&g_pfnOrgMalloc },
+#ifdef RT_OS_DARWIN
+        { "malloc_size", (PFNRT)rtMemReplacementMallocSize,  (PFNRT)malloc_size,  (PFNRT *)&g_pfnOrgMallocSize },
+#endif
+    };
+
+    /*
+     * Initialize the jump backs to avoid recursivly entering this function.
+     */
+    for (unsigned i = 0; i < RT_ELEMENTS(aApis); i++)
+        *aApis[i].ppfnJumpBack = aApis[i].pfnOrg;
+
+    /*
+     * Give the user an option to skip replacing malloc.
+     */
+    if (getenv("IPRT_DONT_REPLACE_MALLOC"))
+        return;
+
+    /*
+     * Allocate a page for jump back code (we leak it).
+     */
+    uint8_t *pbExecPage = (uint8_t *)RTMemPageAlloc(PAGE_SIZE); AssertFatal(pbExecPage);
+    int rc = RTMemProtect(pbExecPage, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC); AssertFatalRC(rc);
+
+    /*
+     * Do the ground work.
+     */
+    uint8_t *pb = pbExecPage;
+    for (unsigned i = 0; i < RT_ELEMENTS(aApis); i++)
+    {
+        /* Resolve it. */
+        PFNRT pfnOrg = (PFNRT)(uintptr_t)dlsym(RTLD_DEFAULT, aApis[i].pszName);
+        if (pfnOrg)
+            aApis[i].pfnOrg = pfnOrg;
+        else
+            pfnOrg = aApis[i].pfnOrg;
+
+        /* Figure what we can replace and how much to duplicate in the jump back code. */
+# ifdef RT_ARCH_AMD64
+        uint32_t         cbNeeded   = 12;
+        DISCPUMODE const enmCpuMode = DISCPUMODE_64BIT;
+# elif defined(RT_ARCH_X86)
+        uint32_t   const cbNeeded   = 5;
+        DISCPUMODE const enmCpuMode = DISCPUMODE_32BIT;
+# else
+#  error "Port me"
+# endif
+        uint32_t offJmpBack = 0;
+        uint32_t cbCopy = 0;
+        while (offJmpBack < cbNeeded)
+        {
+            DISCPUSTATE Dis;
+            uint32_t cbInstr = 1;
+            rc = DISInstr((void *)((uintptr_t)pfnOrg + offJmpBack), enmCpuMode, &Dis, &cbInstr); AssertFatalRC(rc);
+            AssertFatal(!(Dis.pCurInstr->fOpType & (DISOPTYPE_CONTROLFLOW)));
+# ifdef RT_ARCH_AMD64
+#  ifdef RT_OS_DARWIN
+            /* Kludge for: cmp [malloc_def_zone_state], 1; jg 2; call _malloc_initialize; 2: */
+            if (   Dis.ModRM.Bits.Mod == 0
+                && Dis.ModRM.Bits.Rm == 5 /* wrt RIP */
+                && (Dis.Param2.fUse & (DISUSE_IMMEDIATE16_SX8 | DISUSE_IMMEDIATE32_SX8 | DISUSE_IMMEDIATE64_SX8))
+                && Dis.Param2.uValue == 1
+                && Dis.pCurInstr->uOpcode == OP_CMP)
+            {
+                cbCopy = offJmpBack;
+
+                offJmpBack += cbInstr;
+                rc = DISInstr((void *)((uintptr_t)pfnOrg + offJmpBack), enmCpuMode, &Dis, &cbInstr); AssertFatalRC(rc);
+                if (   Dis.pCurInstr->uOpcode == OP_JNBE
+                    && Dis.Param1.uDisp.i8 == 5)
+                {
+                    offJmpBack += cbInstr + 5;
+                    AssertFatal(offJmpBack >= cbNeeded);
+                    break;
+                }
+            }
+#  endif
+            AssertFatal(!(Dis.ModRM.Bits.Mod == 0 && Dis.ModRM.Bits.Rm == 5 /* wrt RIP */));
+# endif
+            offJmpBack += cbInstr;
+        }
+        if (!cbCopy)
+            cbCopy = offJmpBack;
+
+        /* Assemble the jump back. */
+        memcpy(pb, (void *)(uintptr_t)pfnOrg, cbCopy);
+        uint32_t off = cbCopy;
+# ifdef RT_ARCH_AMD64
+        pb[off++] = 0xff; /* jmp qword [$+8 wrt RIP] */
+        pb[off++] = 0x25;
+        *(uint32_t *)&pb[off] = 0;
+        off += 4;
+        *(uint64_t *)&pb[off] = (uintptr_t)pfnOrg + offJmpBack;
+        off += 8;
+        off = RT_ALIGN_32(off, 16);
+# elif defined(RT_ARCH_X86)
+        pb[off++] = 0xe9; /* jmp rel32 */
+        *(uint32_t *)&pb[off] = (uintptr_t)pfnOrg + offJmpBack - (uintptr_t)&pb[4];
+        off += 4;
+        off = RT_ALIGN_32(off, 8);
+# else
+#  error "Port me"
+# endif
+        *aApis[i].ppfnJumpBack = (PFNRT)(uintptr_t)pb;
+        pb += off;
+    }
+
+    /*
+     * Modify the APIs.
+     */
+    for (unsigned i = 0; i < RT_ELEMENTS(aApis); i++)
+    {
+        pb = (uint8_t *)(uintptr_t)aApis[i].pfnOrg;
+        rc = RTMemProtect(pb, 16, RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC); AssertFatalRC(rc);
+
+# ifdef RT_ARCH_AMD64
+        /* Assemble the LdrLoadDll patch. */
+        *pb++ = 0x48; /* mov rax, qword */
+        *pb++ = 0xb8;
+        *(uint64_t *)pb = (uintptr_t)aApis[i].pfnReplacement;
+        pb += 8;
+        *pb++ = 0xff; /* jmp rax */
+        *pb++ = 0xe0;
+# elif defined(RT_ARCH_X86)
+        *pb++ = 0xe9; /* jmp rel32 */
+        *(uint32_t *)pb = (uintptr_t)aApis[i].pfnReplacement - (uintptr_t)&pb[4];
+# else
+#  error "Port me"
+# endif
+    }
+}
+
+#endif /* RTALLOC_REPLACE_MALLOC && RTALLOC_EFENCE_TRACE */
+
+
+/**
+ * Internal allocator.
+ */
+RTDECL(void *) rtR3MemAlloc(const char *pszOp, RTMEMTYPE enmType, size_t cbUnaligned, size_t cbAligned,
+                            const char *pszTag, void *pvCaller, RT_SRC_POS_DECL)
+{
+    /*
+     * Sanity.
+     */
+    if (    RT_ALIGN_Z(RTALLOC_EFENCE_SIZE, PAGE_SIZE) != RTALLOC_EFENCE_SIZE
+        &&  RTALLOC_EFENCE_SIZE <= 0)
+    {
+        rtmemComplain(pszOp, "Invalid E-fence size! %#x\n", RTALLOC_EFENCE_SIZE);
+        return NULL;
+    }
+    if (!cbUnaligned)
+    {
+#if 0
+        rtmemComplain(pszOp, "Request of ZERO bytes allocation!\n");
+        return NULL;
+#else
+        cbAligned = cbUnaligned = 1;
+#endif
+    }
+
+#ifndef RTALLOC_EFENCE_IN_FRONT
+    /* Alignment decreases fence accuracy, but this is at least partially
+     * counteracted by filling and checking the alignment padding. When the
+     * fence is in front then then no extra alignment is needed. */
+    cbAligned = RT_ALIGN_Z(cbAligned, RTALLOC_EFENCE_ALIGNMENT);
+#endif
+
+#ifdef RTALLOC_EFENCE_TRACE
+    /*
+     * Allocate the trace block.
+     */
+    PRTMEMBLOCK pBlock = rtmemBlockCreate(enmType, cbUnaligned, cbAligned, pszTag, pvCaller, RT_SRC_POS_ARGS);
+    if (!pBlock)
+    {
+        rtmemComplain(pszOp, "Failed to allocate trace block!\n");
+        return NULL;
+    }
+#endif
+
+    /*
+     * Allocate a block with page alignment space + the size of the E-fence.
+     */
+    size_t  cbBlock = RT_ALIGN_Z(cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE;
+    void   *pvBlock = RTMemPageAlloc(cbBlock);
+    if (pvBlock)
+    {
+        /*
+         * Calc the start of the fence and the user block
+         * and then change the page protection of the fence.
+         */
+#ifdef RTALLOC_EFENCE_IN_FRONT
+        void *pvEFence = pvBlock;
+        void *pv       = (char *)pvEFence + RTALLOC_EFENCE_SIZE;
+# ifdef RTALLOC_EFENCE_NOMAN_FILLER
+        memset((char *)pv + cbUnaligned, RTALLOC_EFENCE_NOMAN_FILLER, cbBlock - RTALLOC_EFENCE_SIZE - cbUnaligned);
+# endif
+#else
+        void *pvEFence = (char *)pvBlock + (cbBlock - RTALLOC_EFENCE_SIZE);
+        void *pv       = (char *)pvEFence - cbAligned;
+# ifdef RTALLOC_EFENCE_NOMAN_FILLER
+        memset(pvBlock, RTALLOC_EFENCE_NOMAN_FILLER, cbBlock - RTALLOC_EFENCE_SIZE - cbAligned);
+        memset((char *)pv + cbUnaligned, RTALLOC_EFENCE_NOMAN_FILLER, cbAligned - cbUnaligned);
+# endif
+#endif
+
+#ifdef RTALLOC_EFENCE_FENCE_FILLER
+        memset(pvEFence, RTALLOC_EFENCE_FENCE_FILLER, RTALLOC_EFENCE_SIZE);
+#endif
+        int rc = RTMemProtect(pvEFence, RTALLOC_EFENCE_SIZE, RTMEM_PROT_NONE);
+        if (!rc)
+        {
+#ifdef RTALLOC_EFENCE_TRACE
+            rtmemBlockInsert(pBlock, pv);
+#endif
+            if (enmType == RTMEMTYPE_RTMEMALLOCZ)
+                memset(pv, 0, cbUnaligned);
+#ifdef RTALLOC_EFENCE_FILLER
+            else
+                memset(pv, RTALLOC_EFENCE_FILLER, cbUnaligned);
+#endif
+
+            rtmemLog(pszOp, "returns %p (pvBlock=%p cbBlock=%#x pvEFence=%p cbUnaligned=%#x)\n", pv, pvBlock, cbBlock, pvEFence, cbUnaligned);
+            return pv;
+        }
+        rtmemComplain(pszOp, "RTMemProtect failed, pvEFence=%p size %d, rc=%d\n", pvEFence, RTALLOC_EFENCE_SIZE, rc);
+        RTMemPageFree(pvBlock, cbBlock);
+    }
+    else
+        rtmemComplain(pszOp, "Failed to allocated %lu (%lu) bytes.\n", (unsigned long)cbBlock, (unsigned long)cbUnaligned);
+
+#ifdef RTALLOC_EFENCE_TRACE
+    rtmemBlockFree(pBlock);
+#endif
+    return NULL;
+}
+
+
+/**
+ * Internal free.
+ */
+RTDECL(void) rtR3MemFree(const char *pszOp, RTMEMTYPE enmType, void *pv, size_t cbUser, void *pvCaller, RT_SRC_POS_DECL)
+{
+    NOREF(enmType); RT_SRC_POS_NOREF();
+
+    /*
+     * Simple case.
+     */
+    if (!pv)
+        return;
+
+    /*
+     * Check watch points.
+     */
+    for (unsigned i = 0; i < RT_ELEMENTS(gapvRTMemFreeWatch); i++)
+        if (gapvRTMemFreeWatch[i] == pv)
+            RTAssertDoPanic();
+
+#ifdef RTALLOC_EFENCE_TRACE
+    /*
+     * Find the block.
+     */
+    PRTMEMBLOCK pBlock = rtmemBlockRemove(pv);
+    if (pBlock)
+    {
+        if (gfRTMemFreeLog)
+            RTLogPrintf("RTMem %s: pv=%p pvCaller=%p cbUnaligned=%#x\n", pszOp, pv, pvCaller, pBlock->cbUnaligned);
+
+# ifdef RTALLOC_EFENCE_NOMAN_FILLER
+        /*
+         * Check whether the no man's land is untouched.
+         */
+#  ifdef RTALLOC_EFENCE_IN_FRONT
+        void *pvWrong = ASMMemFirstMismatchingU8((char *)pv + pBlock->cbUnaligned,
+                                                 RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) - pBlock->cbUnaligned,
+                                                 RTALLOC_EFENCE_NOMAN_FILLER);
+#  else
+        /* Alignment must match allocation alignment in rtMemAlloc(). */
+        void  *pvWrong = ASMMemFirstMismatchingU8((char *)pv + pBlock->cbUnaligned,
+                                                  pBlock->cbAligned - pBlock->cbUnaligned,
+                                                  RTALLOC_EFENCE_NOMAN_FILLER);
+        if (pvWrong)
+            RTAssertDoPanic();
+        pvWrong = ASMMemFirstMismatchingU8((void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK),
+                                           RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) - pBlock->cbAligned,
+                                           RTALLOC_EFENCE_NOMAN_FILLER);
+#  endif
+        if (pvWrong)
+            RTAssertDoPanic();
+# endif
+
+        /*
+         * Fill the user part of the block.
+         */
+        AssertMsg(enmType != RTMEMTYPE_RTMEMFREEZ || cbUser == pBlock->cbUnaligned,
+                  ("cbUser=%#zx cbUnaligned=%#zx\n", cbUser, pBlock->cbUnaligned));
+        RT_NOREF(cbUser);
+        if (enmType == RTMEMTYPE_RTMEMFREEZ)
+            RT_BZERO(pv, pBlock->cbUnaligned);
+# ifdef RTALLOC_EFENCE_FREE_FILL
+        else
+            memset(pv, RTALLOC_EFENCE_FREE_FILL, pBlock->cbUnaligned);
+# endif
+
+# if defined(RTALLOC_EFENCE_FREE_DELAYED) && RTALLOC_EFENCE_FREE_DELAYED > 0
+        /*
+         * We're doing delayed freeing.
+         * That means we'll expand the E-fence to cover the entire block.
+         */
+        int rc = RTMemProtect(pv, pBlock->cbAligned, RTMEM_PROT_NONE);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Insert it into the free list and process pending frees.
+             */
+            rtmemBlockDelayInsert(pBlock);
+            while ((pBlock = rtmemBlockDelayRemove()) != NULL)
+            {
+                pv = pBlock->Core.Key;
+#  ifdef RTALLOC_EFENCE_IN_FRONT
+                void  *pvBlock = (char *)pv - RTALLOC_EFENCE_SIZE;
+#  else
+                void  *pvBlock = (void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK);
+#  endif
+                size_t cbBlock = RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE;
+                rc = RTMemProtect(pvBlock, cbBlock, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+                if (RT_SUCCESS(rc))
+                    RTMemPageFree(pvBlock, RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE);
+                else
+                    rtmemComplain(pszOp, "RTMemProtect(%p, %#x, RTMEM_PROT_READ | RTMEM_PROT_WRITE) -> %d\n", pvBlock, cbBlock, rc);
+                rtmemBlockFree(pBlock);
+            }
+        }
+        else
+            rtmemComplain(pszOp, "Failed to expand the efence of pv=%p cb=%d, rc=%d.\n", pv, pBlock, rc);
+
+# else /* !RTALLOC_EFENCE_FREE_DELAYED */
+
+        /*
+         * Turn of the E-fence and free it.
+         */
+#  ifdef RTALLOC_EFENCE_IN_FRONT
+        void *pvBlock = (char *)pv - RTALLOC_EFENCE_SIZE;
+        void *pvEFence = pvBlock;
+#  else
+        void *pvBlock = (void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK);
+        void *pvEFence = (char *)pv + pBlock->cb;
+#  endif
+        int rc = RTMemProtect(pvEFence, RTALLOC_EFENCE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+        if (RT_SUCCESS(rc))
+            RTMemPageFree(pvBlock, RT_ALIGN_Z(pBlock->cbAligned, PAGE_SIZE) + RTALLOC_EFENCE_SIZE);
+        else
+            rtmemComplain(pszOp, "RTMemProtect(%p, %#x, RTMEM_PROT_READ | RTMEM_PROT_WRITE) -> %d\n", pvEFence, RTALLOC_EFENCE_SIZE, rc);
+        rtmemBlockFree(pBlock);
+
+# endif /* !RTALLOC_EFENCE_FREE_DELAYED */
+    }
+    else
+        rtmemComplain(pszOp, "pv=%p not found! Incorrect free!\n", pv);
+
+#else /* !RTALLOC_EFENCE_TRACE */
+
+    /*
+     * We have no size tracking, so we're not doing any freeing because
+     * we cannot if the E-fence is after the block.
+     * Let's just expand the E-fence to the first page of the user bit
+     * since we know that it's around.
+     */
+    if (enmType == RTMEMTYPE_RTMEMFREEZ)
+        RT_BZERO(pv, cbUser);
+    int rc = RTMemProtect((void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK), PAGE_SIZE, RTMEM_PROT_NONE);
+    if (RT_FAILURE(rc))
+        rtmemComplain(pszOp, "RTMemProtect(%p, PAGE_SIZE, RTMEM_PROT_NONE) -> %d\n", (void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK), rc);
+#endif /* !RTALLOC_EFENCE_TRACE */
+}
+
+
+/**
+ * Internal realloc.
+ */
+RTDECL(void *) rtR3MemRealloc(const char *pszOp, RTMEMTYPE enmType, void *pvOld, size_t cbNew,
+                              const char *pszTag, void *pvCaller, RT_SRC_POS_DECL)
+{
+    /*
+     * Allocate new and copy.
+     */
+    if (!pvOld)
+        return rtR3MemAlloc(pszOp, enmType, cbNew, cbNew, pszTag, pvCaller, RT_SRC_POS_ARGS);
+    if (!cbNew)
+    {
+        rtR3MemFree(pszOp, RTMEMTYPE_RTMEMREALLOC, pvOld, 0, pvCaller, RT_SRC_POS_ARGS);
+        return NULL;
+    }
+
+#ifdef RTALLOC_EFENCE_TRACE
+
+    /*
+     * Get the block, allocate the new, copy the data, free the old one.
+     */
+    PRTMEMBLOCK pBlock = rtmemBlockGet(pvOld);
+    if (pBlock)
+    {
+        void *pvRet = rtR3MemAlloc(pszOp, enmType, cbNew, cbNew, pszTag, pvCaller, RT_SRC_POS_ARGS);
+        if (pvRet)
+        {
+            memcpy(pvRet, pvOld, RT_MIN(cbNew, pBlock->cbUnaligned));
+            rtR3MemFree(pszOp, RTMEMTYPE_RTMEMREALLOC, pvOld, 0, pvCaller, RT_SRC_POS_ARGS);
+        }
+        return pvRet;
+    }
+    else
+        rtmemComplain(pszOp, "pvOld=%p was not found!\n", pvOld);
+    return NULL;
+
+#else /* !RTALLOC_EFENCE_TRACE */
+
+    rtmemComplain(pszOp, "Not supported if RTALLOC_EFENCE_TRACE isn't defined!\n");
+    return NULL;
+
+#endif /* !RTALLOC_EFENCE_TRACE */
+}
+
+
+
+
+RTDECL(void *)  RTMemEfTmpAlloc(size_t cb, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("TmpAlloc", RTMEMTYPE_RTMEMALLOC, cb, cb, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfTmpAllocZ(size_t cb, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("TmpAlloc", RTMEMTYPE_RTMEMALLOCZ, cb, cb, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void)    RTMemEfTmpFree(void *pv, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void)    RTMemEfTmpFreeZ(void *pv, size_t cb, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("FreeZ", RTMEMTYPE_RTMEMFREEZ, pv, cb, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfAlloc(size_t cb, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("Alloc", RTMEMTYPE_RTMEMALLOC, cb, cb, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfAllocZ(size_t cb, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("AllocZ", RTMEMTYPE_RTMEMALLOCZ, cb, cb, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfAllocVar(size_t cbUnaligned, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+    return rtR3MemAlloc("Alloc", RTMEMTYPE_RTMEMALLOC, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfAllocZVar(size_t cbUnaligned, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+    return rtR3MemAlloc("AllocZ", RTMEMTYPE_RTMEMALLOCZ, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfRealloc(void *pvOld, size_t cbNew, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    return rtR3MemRealloc("Realloc", RTMEMTYPE_RTMEMREALLOC, pvOld, cbNew, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *)  RTMemEfReallocZ(void *pvOld, size_t cbOld, size_t cbNew, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    void *pvDst = rtR3MemRealloc("ReallocZ", RTMEMTYPE_RTMEMREALLOC, pvOld, cbNew, pszTag, ASMReturnAddress(), RT_SRC_POS_ARGS);
+    if (pvDst && cbNew > cbOld)
+        memset((uint8_t *)pvDst + cbOld, 0, cbNew - cbOld);
+    return pvDst;
+}
+
+
+RTDECL(void)    RTMemEfFree(void *pv, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void)    RTMemEfFreeZ(void *pv, size_t cb, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("FreeZ", RTMEMTYPE_RTMEMFREEZ, pv, cb, ASMReturnAddress(), RT_SRC_POS_ARGS);
+}
+
+
+RTDECL(void *) RTMemEfDup(const void *pvSrc, size_t cb, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    void *pvDst = RTMemEfAlloc(cb, pszTag, RT_SRC_POS_ARGS);
+    if (pvDst)
+        memcpy(pvDst, pvSrc, cb);
+    return pvDst;
+}
+
+
+RTDECL(void *) RTMemEfDupEx(const void *pvSrc, size_t cbSrc, size_t cbExtra, const char *pszTag, RT_SRC_POS_DECL) RT_NO_THROW_DEF
+{
+    void *pvDst = RTMemEfAlloc(cbSrc + cbExtra, pszTag, RT_SRC_POS_ARGS);
+    if (pvDst)
+    {
+        memcpy(pvDst, pvSrc, cbSrc);
+        memset((uint8_t *)pvDst + cbSrc, 0, cbExtra);
+    }
+    return pvDst;
+}
+
+
+
+
+/*
+ *
+ * The NP (no position) versions.
+ *
+ */
+
+
+
+RTDECL(void *)  RTMemEfTmpAllocNP(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("TmpAlloc", RTMEMTYPE_RTMEMALLOC, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfTmpAllocZNP(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("TmpAllocZ", RTMEMTYPE_RTMEMALLOCZ, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void)    RTMemEfTmpFreeNP(void *pv) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void)    RTMemEfTmpFreeZNP(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("FreeZ", RTMEMTYPE_RTMEMFREEZ, pv, cb, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfAllocNP(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("Alloc", RTMEMTYPE_RTMEMALLOC, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfAllocZNP(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtR3MemAlloc("AllocZ", RTMEMTYPE_RTMEMALLOCZ, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfAllocVarNP(size_t cbUnaligned, const char *pszTag) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+    return rtR3MemAlloc("Alloc", RTMEMTYPE_RTMEMALLOC, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfAllocZVarNP(size_t cbUnaligned, const char *pszTag) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+    return rtR3MemAlloc("AllocZ", RTMEMTYPE_RTMEMALLOCZ, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfReallocNP(void *pvOld, size_t cbNew, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtR3MemRealloc("Realloc", RTMEMTYPE_RTMEMREALLOC, pvOld, cbNew, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *)  RTMemEfReallocZNP(void *pvOld, size_t cbOld, size_t cbNew, const char *pszTag) RT_NO_THROW_DEF
+{
+    void *pvDst = rtR3MemRealloc("ReallocZ", RTMEMTYPE_RTMEMREALLOC, pvOld, cbNew, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+    if (pvDst && cbNew > cbOld)
+        memset((uint8_t *)pvDst + cbOld, 0, cbNew - cbOld);
+    return pvDst;
+}
+
+
+RTDECL(void)    RTMemEfFreeNP(void *pv) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void)    RTMemEfFreeZNP(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    if (pv)
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREEZ, pv, cb, ASMReturnAddress(), NULL, 0, NULL);
+}
+
+
+RTDECL(void *) RTMemEfDupNP(const void *pvSrc, size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    void *pvDst = RTMemEfAlloc(cb, pszTag, NULL, 0, NULL);
+    if (pvDst)
+        memcpy(pvDst, pvSrc, cb);
+    return pvDst;
+}
+
+
+RTDECL(void *) RTMemEfDupExNP(const void *pvSrc, size_t cbSrc, size_t cbExtra, const char *pszTag) RT_NO_THROW_DEF
+{
+    void *pvDst = RTMemEfAlloc(cbSrc + cbExtra, pszTag, NULL, 0, NULL);
+    if (pvDst)
+    {
+        memcpy(pvDst, pvSrc, cbSrc);
+        memset((uint8_t *)pvDst + cbSrc, 0, cbExtra);
+    }
+    return pvDst;
+}
+
diff --git a/src/VBox/Runtime/r3/alloc-ef.h b/src/VBox/Runtime/r3/alloc-ef.h
new file mode 100644
index 00000000..c6536e7c
--- /dev/null
+++ b/src/VBox/Runtime/r3/alloc-ef.h
@@ -0,0 +1,231 @@
+/* $Id: alloc-ef.h $ */
+/** @file
+ * IPRT - Memory Allocation, electric fence.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_alloc_ef_h
+#define IPRT_INCLUDED_SRC_r3_alloc_ef_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+/*******************************************************************************
+*   Defined Constants And Macros                                               *
+*******************************************************************************/
+#if defined(DOXYGEN_RUNNING)
+# define RTALLOC_USE_EFENCE
+# define RTALLOC_EFENCE_IN_FRONT
+# define RTALLOC_EFENCE_FREE_FILL 'f'
+#endif
+
+/** @def RTALLOC_USE_EFENCE
+ * If defined the electric fence put up for ALL allocations by RTMemAlloc(),
+ * RTMemAllocZ(), RTMemRealloc(), RTMemTmpAlloc() and RTMemTmpAllocZ().
+ */
+#if 0
+# define RTALLOC_USE_EFENCE
+#endif
+
+/** @def RTALLOC_EFENCE_SIZE
+ * The size of the fence. This must be page aligned.
+ */
+#define RTALLOC_EFENCE_SIZE             PAGE_SIZE
+
+/** @def RTALLOC_EFENCE_ALIGNMENT
+ * The allocation alignment, power of two of course.
+ *
+ * Use this for working around misaligned sizes, usually stemming from
+ * allocating a string or something after the main structure.  When you
+ * encounter this, please fix the allocation to RTMemAllocVar or RTMemAllocZVar.
+ */
+#if 0
+# define RTALLOC_EFENCE_ALIGNMENT       (ARCH_BITS / 8)
+#else
+# define RTALLOC_EFENCE_ALIGNMENT       1
+#endif
+
+/** @def RTALLOC_EFENCE_IN_FRONT
+ * Define this to put the fence up in front of the block.
+ * The default (when this isn't defined) is to up it up after the block.
+ */
+//# define RTALLOC_EFENCE_IN_FRONT
+
+/** @def RTALLOC_EFENCE_TRACE
+ * Define this to support actual free and reallocation of blocks.
+ */
+#define RTALLOC_EFENCE_TRACE
+
+/** @def RTALLOC_EFENCE_FREE_DELAYED
+ * This define will enable free() delay and protection of the freed data
+ * while it's being delayed. The value of RTALLOC_EFENCE_FREE_DELAYED defines
+ * the threshold of the delayed blocks.
+ * Delayed blocks does not consume any physical memory, only virtual address space.
+ * Requires RTALLOC_EFENCE_TRACE.
+ */
+#define RTALLOC_EFENCE_FREE_DELAYED     (20 * _1M)
+
+/** @def RTALLOC_EFENCE_FREE_FILL
+ * This define will enable memset(,RTALLOC_EFENCE_FREE_FILL,)'ing the user memory
+ * in the block before freeing/decommitting it. This is useful in GDB since GDB
+ * appears to be able to read the content of the page even after it's been
+ * decommitted.
+ * Requires RTALLOC_EFENCE_TRACE.
+ */
+#if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS) || defined(DOXYGEN_RUNNING)
+# define RTALLOC_EFENCE_FREE_FILL       'f'
+#endif
+
+/** @def RTALLOC_EFENCE_FILLER
+ * This define will enable memset(,RTALLOC_EFENCE_FILLER,)'ing the allocated
+ * memory when the API doesn't require it to be zero'd.
+ */
+#define RTALLOC_EFENCE_FILLER           0xef
+
+/** @def RTALLOC_EFENCE_NOMAN_FILLER
+ * This define will enable memset(,RTALLOC_EFENCE_NOMAN_FILLER,)'ing the
+ * unprotected but not allocated area of memory, the so called no man's land.
+ */
+#define RTALLOC_EFENCE_NOMAN_FILLER     0xaa
+
+/** @def RTALLOC_EFENCE_FENCE_FILLER
+ * This define will enable memset(,RTALLOC_EFENCE_FENCE_FILLER,)'ing the
+ * fence itself, as debuggers can usually read them.
+ */
+#define RTALLOC_EFENCE_FENCE_FILLER     0xcc
+
+#if defined(DOXYGEN_RUNNING)
+/** @def RTALLOC_EFENCE_CPP
+ * This define will enable the new and delete wrappers.
+ */
+# define RTALLOC_EFENCE_CPP
+#endif
+
+#if defined(RUNNING_DOXYGEN)
+/** @def RTALLOC_REPLACE_MALLOC
+ * Replaces the malloc, calloc, realloc, free and friends in libc (experimental).
+ * Set in LocalConfig.kmk. Requires RTALLOC_EFENCE_TRACE to work. */
+# define RTALLOC_REPLACE_MALLOC
+#endif
+#if defined(RTALLOC_REPLACE_MALLOC) && !defined(RTALLOC_EFENCE_TRACE)
+# error "RTALLOC_REPLACE_MALLOC requires RTALLOC_EFENCE_TRACE."
+#endif
+
+
+/*******************************************************************************
+*   Header Files                                                               *
+*******************************************************************************/
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/windows.h>
+#else
+# include <sys/mman.h>
+#endif
+#include <iprt/avl.h>
+#include <iprt/thread.h>
+
+
+/*******************************************************************************
+*   Structures and Typedefs                                                    *
+*******************************************************************************/
+/**
+ * Allocation types.
+ */
+typedef enum RTMEMTYPE
+{
+    RTMEMTYPE_RTMEMALLOC,
+    RTMEMTYPE_RTMEMALLOCZ,
+    RTMEMTYPE_RTMEMREALLOC,
+    RTMEMTYPE_RTMEMFREE,
+    RTMEMTYPE_RTMEMFREEZ,
+
+    RTMEMTYPE_NEW,
+    RTMEMTYPE_NEW_ARRAY,
+    RTMEMTYPE_DELETE,
+    RTMEMTYPE_DELETE_ARRAY
+} RTMEMTYPE;
+
+#ifdef RTALLOC_EFENCE_TRACE
+/**
+ * Node tracking a memory allocation.
+ */
+typedef struct RTMEMBLOCK
+{
+    /** Avl node code, key is the user block pointer. */
+    AVLPVNODECORE   Core;
+    /** Allocation type. */
+    RTMEMTYPE       enmType;
+    /** The unaligned size of the block. */
+    size_t          cbUnaligned;
+    /** The aligned size of the block. */
+    size_t          cbAligned;
+    /** The allocation tag (read-only string). */
+    const char     *pszTag;
+    /** The return address of the allocator function. */
+    void           *pvCaller;
+    /** Line number of the alloc call. */
+    unsigned        iLine;
+    /** File from within the allocation was made. */
+    const char     *pszFile;
+    /** Function from within the allocation was made. */
+    const char     *pszFunction;
+} RTMEMBLOCK, *PRTMEMBLOCK;
+
+#endif
+
+
+/*******************************************************************************
+*   Internal Functions                                                         *
+******************************************************************************/
+RT_C_DECLS_BEGIN
+RTDECL(void *)  rtR3MemAlloc(const char *pszOp, RTMEMTYPE enmType, size_t cbUnaligned, size_t cbAligned,
+                             const char *pszTag, void *pvCaller, RT_SRC_POS_DECL);
+RTDECL(void *)  rtR3MemRealloc(const char *pszOp, RTMEMTYPE enmType, void *pvOld, size_t cbNew,
+                               const char *pszTag, void *pvCaller, RT_SRC_POS_DECL);
+RTDECL(void)    rtR3MemFree(const char *pszOp, RTMEMTYPE enmType, void *pv, size_t cbUser, void *pvCaller, RT_SRC_POS_DECL);
+RT_C_DECLS_END
+
+
+/*******************************************************************************
+*   Global Variables                                                           *
+*******************************************************************************/
+#ifdef RTALLOC_REPLACE_MALLOC
+RT_C_DECLS_BEGIN
+extern void * (*g_pfnOrgMalloc)(size_t);
+extern void * (*g_pfnOrgCalloc)(size_t, size_t);
+extern void * (*g_pfnOrgRealloc)(void *, size_t);
+extern void   (*g_pfnOrgFree)(void *);
+RT_C_DECLS_END
+#endif
+
+#endif /* !IPRT_INCLUDED_SRC_r3_alloc_ef_h */
+
diff --git a/src/VBox/Runtime/r3/alloc.cpp b/src/VBox/Runtime/r3/alloc.cpp
new file mode 100644
index 00000000..015df135
--- /dev/null
+++ b/src/VBox/Runtime/r3/alloc.cpp
@@ -0,0 +1,317 @@
+/* $Id: alloc.cpp $ */
+/** @file
+ * IPRT - Memory Allocation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#if defined(RTMEM_WRAP_TO_EF_APIS) && !defined(RTMEM_NO_WRAP_TO_EF_APIS)
+# undef RTMEM_WRAP_TO_EF_APIS
+# define RTALLOC_USE_EFENCE 1
+#endif
+
+/*#define RTMEMALLOC_USE_TRACKER*/
+/* Don't enable the tracker when building the minimal IPRT. */
+#ifdef RT_MINI
+# undef RTMEMALLOC_USE_TRACKER
+#endif
+
+#if defined(RTMEMALLOC_USE_TRACKER) && defined(RTALLOC_USE_EFENCE)
+# error "Cannot define both RTMEMALLOC_USE_TRACKER and RTALLOC_USE_EFENCE!"
+#endif
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "alloc-ef.h"
+#include <iprt/mem.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#ifdef RTMEMALLOC_USE_TRACKER
+# include <iprt/memtracker.h>
+#endif
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include "internal/mem.h"
+
+#include <stdlib.h>
+
+#undef RTMemTmpAlloc
+#undef RTMemTmpAllocTag
+#undef RTMemTmpAllocZ
+#undef RTMemTmpAllocZTag
+#undef RTMemTmpFree
+#undef RTMemTmpFreeZ
+#undef RTMemAlloc
+#undef RTMemAllocTag
+#undef RTMemAllocZ
+#undef RTMemAllocZTag
+#undef RTMemAllocVar
+#undef RTMemAllocVarTag
+#undef RTMemAllocZVar
+#undef RTMemAllocZVarTag
+#undef RTMemRealloc
+#undef RTMemReallocTag
+#undef RTMemFree
+#undef RTMemFreeZ
+#undef RTMemDup
+#undef RTMemDupTag
+#undef RTMemDupEx
+#undef RTMemDupExTag
+
+#undef RTALLOC_USE_EFENCE
+
+
+#ifdef IPRT_WITH_GCC_SANITIZER
+/**
+ * Checks if @a pszTag is a leak tag.
+ *
+ * @returns true if leak tag, false if not.
+ * @param   pszTag              Tage to inspect.
+ */
+DECLINLINE(bool) rtMemIsLeakTag(const char *pszTag)
+{
+    char ch = *pszTag;
+    if (ch != 'w')
+    { /* likely */ }
+    else
+        return pszTag[1] == 'i'
+            && pszTag[2] == 'l'
+            && pszTag[3] == 'l'
+            && pszTag[4] == '-'
+            && pszTag[5] == 'l'
+            && pszTag[6] == 'e'
+            && pszTag[7] == 'a'
+            && pszTag[8] == 'k';
+    if (ch != 'm')
+        return false;
+    return pszTag[1] == 'm'
+        && pszTag[2] == 'a'
+        && pszTag[3] == 'y'
+        && pszTag[4] == '-'
+        && pszTag[5] == 'l'
+        && pszTag[6] == 'e'
+        && pszTag[7] == 'a'
+        && pszTag[8] == 'k';
+}
+#endif /* IPRT_WITH_GCC_SANITIZER */
+
+
+RTDECL(void *)  RTMemTmpAllocTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return RTMemAllocTag(cb, pszTag);
+}
+
+
+RTDECL(void *)  RTMemTmpAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return RTMemAllocZTag(cb, pszTag);
+}
+
+
+RTDECL(void) RTMemTmpFree(void *pv) RT_NO_THROW_DEF
+{
+    RTMemFree(pv);
+}
+
+
+RTDECL(void) RTMemTmpFreeZ(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    RTMemFreeZ(pv, cb);
+}
+
+
+RTDECL(void *) RTMemAllocTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+#ifdef RTALLOC_USE_EFENCE
+    void *pv = rtR3MemAlloc("Alloc", RTMEMTYPE_RTMEMALLOC, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+
+#else /* !RTALLOC_USE_EFENCE */
+
+    AssertMsg(cb, ("Allocating ZERO bytes is really not a good idea! Good luck with the next assertion!\n"));
+# ifdef RTMEMALLOC_USE_TRACKER
+    void *pv = RTMemTrackerHdrAlloc(malloc(cb + sizeof(RTMEMTRACKERHDR)), cb, pszTag, ASMReturnAddress(), RTMEMTRACKERMETHOD_ALLOC);
+# else
+    void *pv = malloc(cb); NOREF(pszTag);
+# endif
+    AssertMsg(pv, ("malloc(%#zx) failed!!!\n", cb));
+    AssertMsg(   cb < RTMEM_ALIGNMENT
+              || !((uintptr_t)pv & (RTMEM_ALIGNMENT - 1))
+              || ( (cb & RTMEM_ALIGNMENT) + ((uintptr_t)pv & RTMEM_ALIGNMENT)) == RTMEM_ALIGNMENT
+              , ("pv=%p RTMEM_ALIGNMENT=%#x\n", pv, RTMEM_ALIGNMENT));
+#endif /* !RTALLOC_USE_EFENCE */
+#ifdef IPRT_WITH_GCC_SANITIZER
+    if (rtMemIsLeakTag(pszTag))
+        __lsan_ignore_object(pv);
+#endif
+    return pv;
+}
+
+
+RTDECL(void *) RTMemAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+#ifdef RTALLOC_USE_EFENCE
+    void *pv = rtR3MemAlloc("AllocZ", RTMEMTYPE_RTMEMALLOCZ, cb, cb, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+
+#else /* !RTALLOC_USE_EFENCE */
+
+    AssertMsg(cb, ("Allocating ZERO bytes is really not a good idea! Good luck with the next assertion!\n"));
+
+# ifdef RTMEMALLOC_USE_TRACKER
+    void *pv = RTMemTrackerHdrAlloc(calloc(1, cb + sizeof(RTMEMTRACKERHDR)), cb, pszTag, ASMReturnAddress(), RTMEMTRACKERMETHOD_ALLOCZ);
+#else
+    void *pv = calloc(1, cb); NOREF(pszTag);
+#endif
+    AssertMsg(pv, ("calloc(1,%#zx) failed!!!\n", cb));
+    AssertMsg(   cb < RTMEM_ALIGNMENT
+              || !((uintptr_t)pv & (RTMEM_ALIGNMENT - 1))
+              || ( (cb & RTMEM_ALIGNMENT) + ((uintptr_t)pv & RTMEM_ALIGNMENT)) == RTMEM_ALIGNMENT
+              , ("pv=%p RTMEM_ALIGNMENT=%#x\n", pv, RTMEM_ALIGNMENT));
+#endif /* !RTALLOC_USE_EFENCE */
+#ifdef IPRT_WITH_GCC_SANITIZER
+    if (rtMemIsLeakTag(pszTag))
+        __lsan_ignore_object(pv);
+#endif
+    return pv;
+}
+
+
+RTDECL(void *) RTMemAllocVarTag(size_t cbUnaligned, const char *pszTag) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+#ifdef RTALLOC_USE_EFENCE
+    void *pv = rtR3MemAlloc("AllocVar", RTMEMTYPE_RTMEMALLOC, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+#else
+    void *pv = RTMemAllocTag(cbAligned, pszTag);
+#endif
+    return pv;
+}
+
+
+RTDECL(void *) RTMemAllocZVarTag(size_t cbUnaligned, const char *pszTag) RT_NO_THROW_DEF
+{
+    size_t cbAligned;
+    if (cbUnaligned >= 16)
+        cbAligned = RT_ALIGN_Z(cbUnaligned, 16);
+    else
+        cbAligned = RT_ALIGN_Z(cbUnaligned, sizeof(void *));
+#ifdef RTALLOC_USE_EFENCE
+    void *pv = rtR3MemAlloc("AllocZVar", RTMEMTYPE_RTMEMALLOCZ, cbUnaligned, cbAligned, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+#else
+    void *pv = RTMemAllocZTag(cbAligned, pszTag);
+#endif
+    return pv;
+}
+
+
+RTDECL(void *)  RTMemReallocTag(void *pvOld, size_t cbNew, const char *pszTag) RT_NO_THROW_DEF
+{
+#ifdef RTALLOC_USE_EFENCE
+    void *pv = rtR3MemRealloc("Realloc", RTMEMTYPE_RTMEMREALLOC, pvOld, cbNew, pszTag, ASMReturnAddress(), NULL, 0, NULL);
+
+#else /* !RTALLOC_USE_EFENCE */
+# ifdef RT_STRICT
+    const uintptr_t uOld = (uintptr_t)pvOld; /* overzealous gcc 12 complains it's used over realloc */
+# endif
+
+# ifdef RTMEMALLOC_USE_TRACKER
+    void *pvRealOld  = RTMemTrackerHdrReallocPrep(pvOld, 0, pszTag, ASMReturnAddress());
+    size_t cbRealNew = cbNew || !pvRealOld ? cbNew + sizeof(RTMEMTRACKERHDR) : 0;
+    void *pvNew      = realloc(pvRealOld, cbRealNew);
+    void *pv         = RTMemTrackerHdrReallocDone(pvNew, cbNew, pvOld, pszTag, ASMReturnAddress());
+# else
+    void *pv = realloc(pvOld, cbNew); NOREF(pszTag);
+# endif
+    AssertMsg(pv || !cbNew, ("realloc(%p, %#zx) failed!!!\n", uOld, cbNew));
+    AssertMsg(   cbNew < RTMEM_ALIGNMENT
+              || !((uintptr_t)pv & (RTMEM_ALIGNMENT - 1))
+              || ( (cbNew & RTMEM_ALIGNMENT) + ((uintptr_t)pv & RTMEM_ALIGNMENT)) == RTMEM_ALIGNMENT
+              , ("pv=%p RTMEM_ALIGNMENT=%#x\n", pv, RTMEM_ALIGNMENT));
+#endif  /* !RTALLOC_USE_EFENCE */
+    return pv;
+}
+
+
+RTDECL(void) RTMemFree(void *pv) RT_NO_THROW_DEF
+{
+    if (pv)
+#ifdef RTALLOC_USE_EFENCE
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREE, pv, 0, ASMReturnAddress(), NULL, 0, NULL);
+#else
+# ifdef RTMEMALLOC_USE_TRACKER
+        pv = RTMemTrackerHdrFree(pv, 0, NULL, ASMReturnAddress(), RTMEMTRACKERMETHOD_FREE);
+# endif
+        free(pv);
+#endif
+}
+
+
+RTDECL(void) RTMemFreeZ(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    if (pv)
+    {
+#ifdef RTALLOC_USE_EFENCE
+        rtR3MemFree("Free", RTMEMTYPE_RTMEMFREEZ, pv, cb, ASMReturnAddress(), NULL, 0, NULL);
+#else
+# ifdef RTMEMALLOC_USE_TRACKER
+        pv = RTMemTrackerHdrFree(pv, cb, NULL, ASMReturnAddress(), RTMEMTRACKERMETHOD_FREE);
+# endif
+        RT_BZERO(pv, cb);
+        free(pv);
+#endif
+    }
+}
+
+
+
+DECLHIDDEN(void *)  rtMemBaseAlloc(size_t cb)
+{
+    Assert(cb > 0 && cb < _1M);
+    return malloc(cb);
+}
+
+
+DECLHIDDEN(void)    rtMemBaseFree(void *pv)
+{
+    free(pv);
+}
+
diff --git a/src/VBox/Runtime/r3/allocex.cpp b/src/VBox/Runtime/r3/allocex.cpp
new file mode 100644
index 00000000..64eb19f9
--- /dev/null
+++ b/src/VBox/Runtime/r3/allocex.cpp
@@ -0,0 +1,152 @@
+/* $Id: allocex.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, Extended Alloc and Free Functions for Ring-3, posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RTMEM_NO_WRAP_TO_EF_APIS
+#include <iprt/mem.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include "internal/magics.h"
+#include "allocex.h"
+
+
+RTDECL(int) RTMemAllocExTag(size_t cb, size_t cbAlignment, uint32_t fFlags, const char *pszTag, void **ppv) RT_NO_THROW_DEF
+{
+    RT_NOREF_PV(pszTag);
+
+    /*
+     * Validate and adjust input.
+     */
+    AssertMsgReturn(!(fFlags & ~RTMEMALLOCEX_FLAGS_VALID_MASK), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+    AssertReturn(cb > 0, VERR_INVALID_PARAMETER);
+    AssertReturn(RT_IS_POWER_OF_TWO(cbAlignment), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(cbAlignment <= sizeof(void *), ("%zu (%#x)\n", cbAlignment, cbAlignment), VERR_UNSUPPORTED_ALIGNMENT);
+
+    if (fFlags & RTMEMALLOCEX_FLAGS_ANY_CTX)
+        return VERR_NOT_SUPPORTED;
+
+    /*
+     * Align the request.
+     */
+    size_t cbAligned = cb;
+    if (cbAlignment)
+        cbAligned = RT_ALIGN_Z(cb, cbAlignment);
+    else
+        cbAligned = RT_ALIGN_Z(cb, sizeof(uint64_t));
+    AssertMsgReturn(cbAligned >= cb && cbAligned <= ~(size_t)0, ("cbAligned=%#zx cb=%#zx", cbAligned, cb),
+                    VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate the requested memory.
+     */
+    void *pv;
+    if (fFlags & (RTMEMALLOCEX_FLAGS_16BIT_REACH | RTMEMALLOCEX_FLAGS_32BIT_REACH))
+    {
+        int rc;
+        if (fFlags & RTMEMALLOCEX_FLAGS_16BIT_REACH)
+            rc = rtMemAllocEx16BitReach(cbAligned + sizeof(RTMEMHDRR3), fFlags, &pv);
+        else
+            rc = rtMemAllocEx32BitReach(cbAligned + sizeof(RTMEMHDRR3), fFlags, &pv);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+    else if (fFlags & RTMEMALLOCEX_FLAGS_EXEC)
+    {
+        pv = RTMemPageAlloc(cbAligned + sizeof(RTMEMHDRR3));
+        if (pv)
+        {
+            if (fFlags & RTMEMALLOCEX_FLAGS_ZEROED)
+                RT_BZERO(pv, cbAligned + sizeof(RTMEMHDRR3));
+
+            int rc = RTMemProtect(pv, cbAligned + sizeof(RTMEMHDRR3), RTMEM_PROT_EXEC | RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+            if (RT_FAILURE(rc))
+            {
+                RTMemPageFree(pv, cbAligned + sizeof(RTMEMHDRR3));
+                return rc;
+            }
+        }
+    }
+    else if (fFlags & RTMEMALLOCEX_FLAGS_ZEROED)
+        pv = RTMemAllocZ(cbAligned + sizeof(RTMEMHDRR3));
+    else
+        pv = RTMemAlloc(cbAligned + sizeof(RTMEMHDRR3));
+    if (!pv)
+        return VERR_NO_MEMORY;
+
+    /*
+     * Fill in the header and return.
+     */
+    PRTMEMHDRR3 pHdr = (PRTMEMHDRR3)pv;
+    pHdr->u32Magic  = RTMEMHDR_MAGIC;
+    pHdr->fFlags    = fFlags;
+    pHdr->cb        = (uint32_t)cbAligned;
+    pHdr->cbReq     = (uint32_t)cb;
+
+    *ppv = pHdr + 1;
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTMemAllocExTag);
+
+
+RTDECL(void) RTMemFreeEx(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    if (!pv)
+        return;
+    AssertPtr(pv);
+
+    PRTMEMHDRR3 pHdr = (PRTMEMHDRR3)pv - 1;
+    AssertMsg(pHdr->u32Magic == RTMEMHDR_MAGIC, ("pHdr->u32Magic=%RX32 pv=%p cb=%#x\n", pHdr->u32Magic, pv, cb));
+    pHdr->u32Magic = RTMEMHDR_MAGIC_DEAD;
+    Assert(pHdr->cbReq == cb); RT_NOREF_PV(cb);
+
+    if (pHdr->fFlags & (RTMEMALLOCEX_FLAGS_16BIT_REACH | RTMEMALLOCEX_FLAGS_32BIT_REACH))
+        rtMemFreeExYyBitReach(pHdr, pHdr->cb + sizeof(*pHdr), pHdr->fFlags);
+    else if (pHdr->fFlags & RTMEMALLOCEX_FLAGS_EXEC)
+    {
+        RTMemProtect(pHdr, pHdr->cb + sizeof(*pHdr), RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+        RTMemPageFree(pHdr, pHdr->cb + sizeof(*pHdr));
+    }
+    else
+        RTMemFree(pHdr);
+}
+RT_EXPORT_SYMBOL(RTMemFreeEx);
+
diff --git a/src/VBox/Runtime/r3/allocex.h b/src/VBox/Runtime/r3/allocex.h
new file mode 100644
index 00000000..91ab656d
--- /dev/null
+++ b/src/VBox/Runtime/r3/allocex.h
@@ -0,0 +1,96 @@
+/* $Id: allocex.h $ */
+/** @file
+ * IPRT - Memory Allocation, Extended Alloc and Free Functions for Ring-3.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_allocex_h
+#define IPRT_INCLUDED_SRC_r3_allocex_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#include <iprt/types.h>
+
+/**
+ * Heading for extended memory allocations in ring-3.
+ */
+typedef struct RTMEMHDRR3
+{
+    /** Magic (RTMEMHDR_MAGIC). */
+    uint32_t    u32Magic;
+    /** Block flags (RTMEMALLOCEX_FLAGS_*). */
+    uint32_t    fFlags;
+    /** The actual size of the block, header not included. */
+    uint32_t    cb;
+    /** The requested allocation size. */
+    uint32_t    cbReq;
+} RTMEMHDRR3;
+/** Pointer to a ring-3 extended memory header. */
+typedef RTMEMHDRR3 *PRTMEMHDRR3;
+
+
+/**
+ * Allocate memory in below 64KB.
+ *
+ * @returns IPRT status code.
+ * @param   cbAlloc             Number of bytes to allocate (including the
+ *                              header if the caller needs one).
+ * @param   fFlags              Allocation flags.
+ * @param   ppv                 Where to return the pointer to the memory.
+ */
+DECLHIDDEN(int) rtMemAllocEx16BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv);
+
+/**
+ * Allocate memory in below 4GB.
+ *
+ * @returns IPRT status code.
+ * @param   cbAlloc             Number of bytes to allocate (including the
+ *                              header if the caller needs one).
+ * @param   fFlags              Allocation flags.
+ * @param   ppv                 Where to return the pointer to the memory.
+ */
+DECLHIDDEN(int) rtMemAllocEx32BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv);
+
+
+/**
+ * Frees memory allocated by rtMemAllocEx16BitReach and rtMemAllocEx32BitReach.
+ *
+ * @param   pv                  Start of allocation.
+ * @param   cb                  Allocation size.
+ * @param   fFlags              Allocation flags.
+ */
+DECLHIDDEN(void) rtMemFreeExYyBitReach(void *pv, size_t cb, uint32_t fFlags);
+
+#endif /* !IPRT_INCLUDED_SRC_r3_allocex_h */
+
diff --git a/src/VBox/Runtime/r3/darwin/Makefile.kup b/src/VBox/Runtime/r3/darwin/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/Makefile.kup
diff --git a/src/VBox/Runtime/r3/darwin/RTCrStoreCreateSnapshotById-darwin.cpp b/src/VBox/Runtime/r3/darwin/RTCrStoreCreateSnapshotById-darwin.cpp
new file mode 100644
index 00000000..aa26ac2d
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/RTCrStoreCreateSnapshotById-darwin.cpp
@@ -0,0 +1,268 @@
+/* $Id: RTCrStoreCreateSnapshotById-darwin.cpp $ */
+/** @file
+ * IPRT - RTCrStoreCreateSnapshotById, Darwin.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/crypto/store.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+
+/* HACK ALERT! Shut up those deprecated messages on SecKeychainSearchCreateFromAttributes and SecKeychainSearchCopyNext. */
+#include <CoreFoundation/CoreFoundation.h>
+#undef  DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#define DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+
+#include <Security/Security.h>
+
+
+/**
+ * Checks the trust settings of the certificate.
+ *
+ * @returns true if not out-right distructed, otherwise false.
+ * @param   hCert           The certificate.
+ * @param   enmTrustDomain  The trust settings domain to check relative to.
+ */
+static bool rtCrStoreIsDarwinCertTrustworthy(SecCertificateRef hCert, SecTrustSettingsDomain enmTrustDomain)
+{
+    bool fResult = true;
+    CFArrayRef hTrustSettings;
+    OSStatus orc = SecTrustSettingsCopyTrustSettings(hCert, enmTrustDomain, &hTrustSettings);
+    if (orc == noErr)
+    {
+        CFIndex const cTrustSettings = CFArrayGetCount(hTrustSettings);
+        for (CFIndex i = 0; i < cTrustSettings; i++)
+        {
+            CFDictionaryRef hDict = (CFDictionaryRef)CFArrayGetValueAtIndex(hTrustSettings, i);
+            AssertContinue(CFGetTypeID(hDict) == CFDictionaryGetTypeID());
+
+            CFNumberRef hNum = (CFNumberRef)CFDictionaryGetValue(hDict, kSecTrustSettingsResult);
+            if (hNum)
+            {
+                AssertContinue(CFGetTypeID(hNum) == CFNumberGetTypeID());
+                SInt32 iNum;
+                if (CFNumberGetValue(hNum, kCFNumberSInt32Type, &iNum))
+                {
+                    if (iNum == kSecTrustSettingsResultDeny)
+                    {
+                        fResult = false;
+                        break;
+                    }
+                }
+                /* No need to release hNum (get rule). */
+            }
+            /* No need to release hDict (get rule). */
+        }
+        CFRelease(hTrustSettings);
+    }
+    else if (orc != errSecItemNotFound)
+    {
+        AssertFailed();
+        fResult = false;
+    }
+    return fResult;
+}
+
+
+static int rtCrStoreAddCertsFromNativeKeychain(RTCRSTORE hStore, SecKeychainRef hKeychain, SecTrustSettingsDomain enmTrustDomain,
+                                               int rc, PRTERRINFO pErrInfo)
+{
+    /** @todo The SecKeychainSearchCreateFromAttributes and
+     * SecKeychainSearchCopyNext APIs have been officially deprecated since 10.7
+     * according to the header files.  However, the perferred API,
+     * SecItemCopyMatching (and possibly SecTrustCopyAnchorCertificates) would
+     * require a larger rewrite here and that's just not worth it right now.  We can
+     * do that should these APIs be removed (unlikely given the amount of grep hits
+     * in the public 10.15.3 sources). */
+
+    /*
+     * Enumerate the certificates in the keychain.
+     */
+    RT_GCC_NO_WARN_DEPRECATED_BEGIN
+    SecKeychainSearchRef hSearch;
+    OSStatus orc = SecKeychainSearchCreateFromAttributes(hKeychain, kSecCertificateItemClass, NULL, &hSearch);
+    if (orc == noErr)
+    {
+        SecKeychainItemRef hItem;
+        while ((orc = SecKeychainSearchCopyNext(hSearch, &hItem)) == noErr)
+        {
+            Assert(CFGetTypeID(hItem) == SecCertificateGetTypeID());
+            SecCertificateRef hCert = (SecCertificateRef)hItem;
+
+            /*
+             * Check if the current certificate is at all trusted, skip it if it's isn't.
+             */
+            if (rtCrStoreIsDarwinCertTrustworthy(hCert, enmTrustDomain))
+            {
+                /*
+                 * Get the certificate data.
+                 */
+                CFDataRef hEncodedCert = SecCertificateCopyData(hCert);
+                Assert(hEncodedCert);
+                if (hEncodedCert)
+                {
+                    CFIndex         cbEncoded = CFDataGetLength(hEncodedCert);
+                    const uint8_t  *pbEncoded = CFDataGetBytePtr(hEncodedCert);
+
+                    RTERRINFOSTATIC StaticErrInfo;
+                    int rc2 = RTCrStoreCertAddEncoded(hStore, RTCRCERTCTX_F_ENC_X509_DER | RTCRCERTCTX_F_ADD_IF_NOT_FOUND,
+                                                      pbEncoded, cbEncoded, RTErrInfoInitStatic(&StaticErrInfo));
+                    if (RT_FAILURE(rc2))
+                    {
+                        if (RTErrInfoIsSet(&StaticErrInfo.Core))
+                            RTErrInfoAddF(pErrInfo, -rc2, "  %s", StaticErrInfo.Core.pszMsg);
+                        else
+                            RTErrInfoAddF(pErrInfo, -rc2, "  %Rrc adding cert", rc2);
+                        rc = -rc2;
+                    }
+
+                    CFRelease(hEncodedCert);
+                }
+            }
+
+            CFRelease(hItem);
+        }
+        if (orc != errSecItemNotFound)
+            rc = RTErrInfoAddF(pErrInfo, -VERR_SEARCH_ERROR,
+                               "  SecKeychainSearchCopyNext failed with %#x", orc);
+        CFRelease(hSearch);
+    }
+    else
+        rc = RTErrInfoAddF(pErrInfo, -VERR_SEARCH_ERROR,
+                           "  SecKeychainSearchCreateFromAttributes failed with %#x", orc);
+    RT_GCC_NO_WARN_DEPRECATED_END
+    return rc;
+}
+
+
+static int rtCrStoreAddCertsFromNativeKeychainFile(RTCRSTORE hStore, const char *pszKeychain,
+                                                   SecTrustSettingsDomain enmTrustDomain,
+                                                   int rc, PRTERRINFO pErrInfo)
+{
+    /*
+     * Open the keychain and call common worker to do the job.
+     */
+    SecKeychainRef hKeychain;
+    OSStatus orc = SecKeychainOpen(pszKeychain, &hKeychain);
+    if (orc == noErr)
+    {
+        rc = rtCrStoreAddCertsFromNativeKeychain(hStore, hKeychain, enmTrustDomain, rc, pErrInfo);
+
+        CFRelease(hKeychain);
+    }
+    else if (RTFileExists(pszKeychain))
+        rc = RTErrInfoAddF(pErrInfo, -VERR_OPEN_FAILED, "  SecKeychainOpen failed with %#x on '%s'", orc, pszKeychain);
+    return rc;
+}
+
+
+static int rtCrStoreAddCertsFromNativeKeystoreDomain(RTCRSTORE hStore, SecPreferencesDomain enmDomain,
+                                                     SecTrustSettingsDomain enmTrustDomain,
+                                                     int rc, PRTERRINFO pErrInfo)
+{
+    /*
+     * Get a list of keystores for this domain and call common worker on each.
+     */
+    CFArrayRef hKeychains;
+    OSStatus orc = SecKeychainCopyDomainSearchList(enmDomain, &hKeychains);
+    if (orc == noErr)
+    {
+        CFIndex const cEntries = CFArrayGetCount(hKeychains);
+        for (CFIndex i = 0; i < cEntries; i++)
+        {
+            SecKeychainRef hKeychain = (SecKeychainRef)CFArrayGetValueAtIndex(hKeychains, i);
+            Assert(CFGetTypeID(hKeychain) == SecKeychainGetTypeID());
+            CFRetain(hKeychain);
+
+            rc = rtCrStoreAddCertsFromNativeKeychain(hStore, hKeychain, enmTrustDomain, rc, pErrInfo);
+
+            CFRelease(hKeychain);
+        }
+
+        CFRelease(hKeychains);
+    }
+    else
+        rc = RTErrInfoAddF(pErrInfo, -VERR_SEARCH_ERROR,
+                           " SecKeychainCopyDomainSearchList failed with %#x on %d", orc, enmDomain);
+    return rc;
+}
+
+
+RTDECL(int) RTCrStoreCreateSnapshotById(PRTCRSTORE phStore, RTCRSTOREID enmStoreId, PRTERRINFO pErrInfo)
+{
+    AssertReturn(enmStoreId > RTCRSTOREID_INVALID && enmStoreId < RTCRSTOREID_END, VERR_INVALID_PARAMETER);
+
+    /*
+     * Create an empty in-memory store.
+     */
+    RTCRSTORE hStore;
+    int rc = RTCrStoreCreateInMem(&hStore, 128);
+    if (RT_SUCCESS(rc))
+    {
+        *phStore = hStore;
+
+        /*
+         * Load the certificates corresponding to the given virtual store ID.
+         */
+        switch (enmStoreId)
+        {
+            case RTCRSTOREID_USER_TRUSTED_CAS_AND_CERTIFICATES:
+                rc = rtCrStoreAddCertsFromNativeKeystoreDomain(hStore, kSecPreferencesDomainUser,
+                                                               kSecTrustSettingsDomainUser, rc, pErrInfo);
+                break;
+
+            case RTCRSTOREID_SYSTEM_TRUSTED_CAS_AND_CERTIFICATES:
+                rc = rtCrStoreAddCertsFromNativeKeystoreDomain(hStore, kSecPreferencesDomainSystem,
+                                                               kSecTrustSettingsDomainSystem, rc, pErrInfo);
+                rc = rtCrStoreAddCertsFromNativeKeychainFile(hStore,
+                                                             "/System/Library/Keychains/SystemRootCertificates.keychain",
+                                                             kSecTrustSettingsDomainSystem, rc, pErrInfo);
+                break;
+
+            default:
+                AssertFailed(); /* implement me */
+        }
+    }
+    else
+        RTErrInfoSet(pErrInfo, rc, "RTCrStoreCreateInMem failed");
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTCrStoreCreateSnapshotById);
+
diff --git a/src/VBox/Runtime/r3/darwin/RTFileQuerySectorSize-darwin.cpp b/src/VBox/Runtime/r3/darwin/RTFileQuerySectorSize-darwin.cpp
new file mode 100644
index 00000000..bf246d48
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/RTFileQuerySectorSize-darwin.cpp
@@ -0,0 +1,89 @@
+/* $Id: RTFileQuerySectorSize-darwin.cpp $ */
+/** @file
+ * IPRT - RTFileQuerySectorSize, Darwin.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <sys/stat.h>
+#include <sys/disk.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <errno.h>
+
+
+RTDECL(int) RTFileQuerySectorSize(RTFILE hFile, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pcbSector, VERR_INVALID_PARAMETER);
+
+    int rc;
+    int const fd = (int)RTFileToNative(hFile);
+    struct stat DevStat = { 0 };
+    if (!fstat(fd, &DevStat))
+    {
+        if (S_ISBLK(DevStat.st_mode) || S_ISCHR(DevStat.st_mode))
+        {
+            uint32_t cbLogicalBlock = 0;
+            if (!ioctl(fd, DKIOCGETBLOCKSIZE, &cbLogicalBlock))
+            {
+                AssertReturn(cbLogicalBlock > 0, VERR_INVALID_FUNCTION);
+                *pcbSector = cbLogicalBlock;
+                return VINF_SUCCESS;
+            }
+
+            rc = RTErrConvertFromErrno(errno);
+            AssertMsgFailed(("ioctl failed: errno=%d / %Rrc\n", errno, rc));
+        }
+        else
+        {
+            AssertMsgFailed(("not a block or character device.\n"));
+            rc = VERR_INVALID_FUNCTION;
+        }
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(errno);
+        AssertMsgFailed(("fstat failed: errno=%d / %Rrc\n", errno, rc));
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/RTMpGetDescription-generic.cpp b/src/VBox/Runtime/r3/darwin/RTMpGetDescription-generic.cpp
new file mode 100644
index 00000000..cf28744d
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/RTMpGetDescription-generic.cpp
@@ -0,0 +1,173 @@
+/* $Id: RTMpGetDescription-generic.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, RTMpGetDescription for darwin/arm.
+ */
+
+/*
+ * Copyright (C) 2009-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/mp.h>
+#include "internal/iprt.h"
+#include <iprt/err.h>
+#include <iprt/string.h>
+
+#include <sys/sysctl.h>
+#if defined(RT_ARCH_ARM64)
+# include <IOKit/IOKitLib.h>
+#endif
+
+
+RTDECL(int) RTMpGetDescription(RTCPUID idCpu, char *pszBuf, size_t cbBuf)
+{
+    /*
+     * Check that the specified cpu is valid & online.
+     */
+    if (idCpu != NIL_RTCPUID && !RTMpIsCpuOnline(idCpu))
+        return RTMpIsCpuPossible(idCpu)
+             ? VERR_CPU_OFFLINE
+             : VERR_CPU_NOT_FOUND;
+
+    /*
+     * For ARM there are typically two different types of cores, so look up the
+     * processor in the IODeviceTree and get the core name and type from there
+     * if we can.
+     */
+    char   szExtra[256];
+    size_t cchExtra = 0;
+
+#if defined(RT_ARCH_ARM64)
+    char szArmCpuPath[64];
+    RTStrPrintf(szArmCpuPath, sizeof(szArmCpuPath), "IODeviceTree:/cpus/cpu%x", idCpu); /** @todo Hex? M1 Max only has 10 cores... */
+    io_registry_entry_t hIoRegEntry = IORegistryEntryFromPath(kIOMasterPortDefault, szArmCpuPath);
+    if (hIoRegEntry != MACH_PORT_NULL)
+    {
+        /* This property is typically "E" or "P".  Don't know why it's mapped
+           to a CFDataRef rather than a CFStringRef... */
+        CFTypeRef hValRef = IORegistryEntryCreateCFProperty(hIoRegEntry, CFSTR("cluster-type"), kCFAllocatorDefault, kNilOptions);
+        if (hValRef)
+        {
+            if (CFGetTypeID(hValRef) == CFDataGetTypeID())
+            {
+                size_t const          cbData = CFDataGetLength((CFDataRef)hValRef);
+                uint8_t const * const pbData = (uint8_t const *)CFDataGetBytePtr((CFDataRef)hValRef);
+                if (cbData > 0 && pbData != NULL)
+                {
+                    int rc = RTStrValidateEncodingEx((const char *)pbData, cbData, RTSTR_VALIDATE_ENCODING_ZERO_TERMINATED);
+                    AssertMsgRC(rc, ("%p LB %#zx: %.*Rhxs\n", pbData, cbData, cbData, pbData));
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTStrCopy(&szExtra[1], sizeof(szExtra) - 1, (const char *)pbData);
+                        szExtra[0] = ' ';
+                        cchExtra = strlen(szExtra);
+                    }
+                }
+            }
+            else
+                AssertMsgFailed(("%p=%#lx\n", hValRef, CFGetTypeID(hValRef)));
+
+            CFRelease(hValRef);
+        }
+
+        /* The compatible property is an "array" of zero terminated strings.
+           For the M1 mini the first entry is either "apple,firestorm" (P cores)
+           or "apple,icestorm" (E cores).  We extract the bits after the comma
+           and append it to the extra string. (Again, dunno why it's a CFDataRef.) */
+        hValRef = IORegistryEntryCreateCFProperty(hIoRegEntry, CFSTR("compatible"), kCFAllocatorDefault, 0);
+        if (hValRef)
+        {
+            if (CFGetTypeID(hValRef) == CFDataGetTypeID())
+            {
+                size_t const          cbData = CFDataGetLength((CFDataRef)hValRef);
+                uint8_t const * const pbData = (uint8_t const *)CFDataGetBytePtr((CFDataRef)hValRef);
+                if (cbData > 0 && pbData != NULL)
+                {
+                    Assert(pbData[cbData - 1] == '\0');
+                    if (pbData[cbData - 1] == '\0')
+                    {
+                        size_t offData = 0;
+                        while (offData < cbData)
+                        {
+                            const char  *psz = (const char *)&pbData[offData];
+                            size_t const cch = strlen(psz);
+
+                            if (RTStrStartsWith(psz, "apple,"))
+                            {
+                                psz += sizeof("apple,") - 1;
+                                psz = RTStrStripL(psz);
+                                if (*psz)
+                                {
+                                    if (RTStrIsValidEncoding(psz))
+                                        cchExtra += RTStrPrintf(&szExtra[cchExtra], sizeof(szExtra) - cchExtra, " (%s)", psz);
+                                    else
+                                        AssertFailed();
+                                }
+                            }
+
+                            /* advance */
+                            offData += cch + 1;
+                        }
+                    }
+                }
+            }
+            else
+                AssertMsgFailed(("%p=%#lx\n", hValRef, CFGetTypeID(hValRef)));
+            CFRelease(hValRef);
+        }
+
+        IOObjectRelease(hIoRegEntry);
+    }
+#endif
+    szExtra[cchExtra] = '\0';
+
+    /*
+     * Just use the sysctl machdep.cpu.brand_string value for now.
+     */
+    char szBrand[128] = {0};
+    size_t cb = sizeof(szBrand);
+    int rc = sysctlbyname("machdep.cpu.brand_string", &szBrand, &cb, NULL, 0);
+    if (rc == -1)
+        szBrand[0] = '\0';
+
+    char *pszStripped = RTStrStrip(szBrand);
+    if (*pszStripped == '\0')
+        pszStripped = strcpy(szBrand, "Unknown");
+
+    rc = RTStrCopy(pszBuf, cbBuf, pszStripped);
+    if (cchExtra > 0 && RT_SUCCESS(rc))
+        rc = RTStrCat(pszBuf, cbBuf, szExtra);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTMpGetDescription);
+
diff --git a/src/VBox/Runtime/r3/darwin/RTPathUserDocuments-darwin.cpp b/src/VBox/Runtime/r3/darwin/RTPathUserDocuments-darwin.cpp
new file mode 100644
index 00000000..296c3857
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/RTPathUserDocuments-darwin.cpp
@@ -0,0 +1,123 @@
+/* $Id: RTPathUserDocuments-darwin.cpp $ */
+/** @file
+ * IPRT - RTPathUserDocuments, darwin ring-3.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/path.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
+# include <sysdir.h>
+#else
+# include <NSSystemDirectories.h>
+#endif
+#include <sys/syslimits.h>
+#ifdef IPRT_USE_CORE_SERVICE_FOR_USER_DOCUMENTS
+# include <CoreServices/CoreServices.h>
+#endif
+
+
+RTDECL(int) RTPathUserDocuments(char *pszPath, size_t cchPath)
+{
+    /*
+     * Validate input
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(cchPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * Try NSSystemDirectories first since that works for directories that doesn't exist.
+     * The NSSystemDirectories API was renamed in 10.12 to sysdir.
+     */
+    int rc = VERR_PATH_NOT_FOUND;
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
+    sysdir_search_path_enumeration_state EnmState = sysdir_start_search_path_enumeration(SYSDIR_DIRECTORY_DOCUMENT,
+                                                                                         SYSDIR_DOMAIN_MASK_USER);
+#else
+    NSSearchPathEnumerationState EnmState = NSStartSearchPathEnumeration(NSDocumentDirectory, NSUserDomainMask);
+#endif
+    if (EnmState != 0)
+    {
+        char szTmp[PATH_MAX];
+        szTmp[0] = szTmp[PATH_MAX - 1] = '\0';
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
+        EnmState = sysdir_get_next_search_path_enumeration(EnmState, szTmp);
+#else
+        EnmState = NSGetNextSearchPathEnumeration(EnmState, szTmp);
+#endif
+        if (EnmState != 0)
+        {
+            size_t cchTmp = strlen(szTmp);
+            if (cchTmp >= cchPath)
+                return VERR_BUFFER_OVERFLOW;
+
+            if (szTmp[0] == '~' && szTmp[1] == '/')
+            {
+                /* Expand tilde. */
+                rc = RTPathUserHome(pszPath, cchPath - cchTmp + 2);
+                if (RT_FAILURE(rc))
+                    return rc;
+                rc = RTPathAppend(pszPath, cchPath, &szTmp[2]);
+            }
+            else
+                rc = RTStrCopy(pszPath, cchPath, szTmp);
+            return rc;
+        }
+    }
+
+#ifdef IPRT_USE_CORE_SERVICE_FOR_USER_DOCUMENTS
+    /*
+     * Fall back on FSFindFolder in case the above should fail...
+     */
+    FSRef ref;
+    OSErr err = FSFindFolder(kOnAppropriateDisk, kDocumentsFolderType, false /* createFolder */, &ref);
+    if (err == noErr)
+    {
+        err = FSRefMakePath(&ref, (UInt8*)pszPath, cchPath);
+        if (err == noErr)
+            return VINF_SUCCESS;
+    }
+#endif
+    Assert(RT_FAILURE_NP(rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/RTSystemQueryDmiString-darwin.cpp b/src/VBox/Runtime/r3/darwin/RTSystemQueryDmiString-darwin.cpp
new file mode 100644
index 00000000..0c644229
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/RTSystemQueryDmiString-darwin.cpp
@@ -0,0 +1,163 @@
+/* $Id: RTSystemQueryDmiString-darwin.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryDmiString, darwin ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+
+#include <mach/mach_port.h>
+#include <IOKit/IOKitLib.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#define IOCLASS_PLATFORMEXPERTDEVICE         "IOPlatformExpertDevice"
+#define PROP_PRODUCT_NAME                    "product-name"
+#define PROP_PRODUCT_VERSION                 "version"
+#define PROP_PRODUCT_SERIAL                  "IOPlatformSerialNumber"
+#define PROP_PRODUCT_UUID                    "IOPlatformUUID"
+#define PROP_MANUFACTURER                    "manufacturer"
+
+
+RTDECL(int) RTSystemQueryDmiString(RTSYSDMISTR enmString, char *pszBuf, size_t cbBuf)
+{
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbBuf > 0, VERR_INVALID_PARAMETER);
+    *pszBuf = '\0';
+    AssertReturn(enmString > RTSYSDMISTR_INVALID && enmString < RTSYSDMISTR_END, VERR_INVALID_PARAMETER);
+
+    CFStringRef PropStringRef = NULL;
+    switch (enmString)
+    {
+        case RTSYSDMISTR_PRODUCT_NAME:    PropStringRef = CFSTR(PROP_PRODUCT_NAME);    break;
+        case RTSYSDMISTR_PRODUCT_VERSION: PropStringRef = CFSTR(PROP_PRODUCT_VERSION); break;
+        case RTSYSDMISTR_PRODUCT_SERIAL:  PropStringRef = CFSTR(PROP_PRODUCT_SERIAL);  break;
+        case RTSYSDMISTR_PRODUCT_UUID:    PropStringRef = CFSTR(PROP_PRODUCT_UUID);    break;
+        case RTSYSDMISTR_MANUFACTURER:    PropStringRef = CFSTR(PROP_MANUFACTURER);    break;
+        default:
+            return VERR_NOT_SUPPORTED;
+    }
+
+    mach_port_t MasterPort;
+    kern_return_t kr = IOMasterPort(MACH_PORT_NULL, &MasterPort);
+    if (kr != kIOReturnSuccess)
+    {
+        if (kr == KERN_NO_ACCESS)
+            return VERR_ACCESS_DENIED;
+        return RTErrConvertFromDarwinIO(kr);
+    }
+
+    CFDictionaryRef ClassToMatch = IOServiceMatching(IOCLASS_PLATFORMEXPERTDEVICE);
+    if (!ClassToMatch)
+        return VERR_NOT_SUPPORTED;
+
+    /* IOServiceGetMatchingServices will always consume ClassToMatch. */
+    io_iterator_t Iterator;
+    kr = IOServiceGetMatchingServices(MasterPort, ClassToMatch, &Iterator);
+    if (kr != kIOReturnSuccess)
+        return RTErrConvertFromDarwinIO(kr);
+
+    int rc = VERR_NOT_SUPPORTED;
+    io_service_t ServiceObject;
+    while ((ServiceObject = IOIteratorNext(Iterator)))
+    {
+        if (   enmString == RTSYSDMISTR_PRODUCT_NAME
+            || enmString == RTSYSDMISTR_PRODUCT_VERSION
+            || enmString == RTSYSDMISTR_MANUFACTURER
+           )
+        {
+            CFDataRef DataRef = (CFDataRef)IORegistryEntryCreateCFProperty(ServiceObject, PropStringRef,
+                                                                           kCFAllocatorDefault, kNilOptions);
+            if (DataRef)
+            {
+                size_t         cbData  = CFDataGetLength(DataRef);
+                const char    *pchData = (const char *)CFDataGetBytePtr(DataRef);
+                rc = RTStrCopyEx(pszBuf, cbBuf, pchData, cbData);
+                CFRelease(DataRef);
+                break;
+            }
+        }
+        else
+        {
+            CFStringRef StringRef = (CFStringRef)IORegistryEntryCreateCFProperty(ServiceObject, PropStringRef,
+                                                                                 kCFAllocatorDefault, kNilOptions);
+            if (StringRef)
+            {
+                Boolean fRc = CFStringGetCString(StringRef, pszBuf, cbBuf, kCFStringEncodingUTF8);
+                if (fRc)
+                    rc = VINF_SUCCESS;
+                else
+                {
+                    CFIndex cwc    = CFStringGetLength(StringRef);
+                    size_t  cbTmp  = cwc + 1;
+                    char   *pszTmp = (char *)RTMemTmpAlloc(cbTmp);
+                    int     cTries = 1;
+                    while (   pszTmp
+                           && (fRc = CFStringGetCString(StringRef, pszTmp, cbTmp, kCFStringEncodingUTF8)) == FALSE
+                           && cTries++ < 4)
+                    {
+                        RTMemTmpFree(pszTmp);
+                        cbTmp *= 2;
+                        pszTmp = (char *)RTMemTmpAlloc(cbTmp);
+                    }
+                    if (fRc)
+                        rc = RTStrCopy(pszBuf, cbBuf, pszTmp);
+                    else if (!pszTmp)
+                        rc = VERR_NO_TMP_MEMORY;
+                    else
+                        rc = VERR_ACCESS_DENIED;
+                    RTMemFree(pszTmp);
+                }
+                CFRelease(StringRef);
+                break;
+            }
+        }
+    }
+
+    IOObjectRelease(ServiceObject);
+    IOObjectRelease(Iterator);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/filelock-darwin.cpp b/src/VBox/Runtime/r3/darwin/filelock-darwin.cpp
new file mode 100644
index 00000000..16d7137d
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/filelock-darwin.cpp
@@ -0,0 +1,178 @@
+/* $Id: filelock-darwin.cpp $ */
+/** @file
+ * IPRT - File Locking, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/fcntl.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include <iprt/file.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+
+
+
+
+RTR3DECL(int)  RTFileLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    Assert(RTFILE_LOCK_WRITE);
+    fl.l_type   = (fLock & RTFILE_LOCK_WRITE) ? F_WRLCK : F_RDLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    Assert(RTFILE_LOCK_WAIT);
+    if (fcntl(RTFileToNative(hFile), (fLock & RTFILE_LOCK_WAIT) ? F_SETLKW : F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+    int iErr = errno;
+    if (iErr == ENOTSUP)
+    {
+        /*
+         * This is really bad hack for getting VDIs to work somewhat
+         * safely on SMB mounts.
+         */
+        /** @todo we need to keep track of these locks really. Anyone requiring to lock more
+         * than one part of a file will have to fix this. */
+        unsigned f = 0;
+        Assert(RTFILE_LOCK_WAIT);
+        if (fLock & RTFILE_LOCK_WAIT)
+            f |= LOCK_NB;
+        if (fLock & RTFILE_LOCK_WRITE)
+            f |= LOCK_EX;
+        else
+            f |= LOCK_SH;
+        if (!flock(RTFileToNative(hFile), f))
+            return VINF_SUCCESS;
+        iErr = errno;
+        if (iErr == EWOULDBLOCK)
+            return VERR_FILE_LOCK_VIOLATION;
+    }
+
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
+
+RTR3DECL(int)  RTFileChangeLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    /** @todo We never returns VERR_FILE_NOT_LOCKED for now. */
+    return RTFileLock(hFile, fLock, offLock, cbLock);
+}
+
+
+RTR3DECL(int)  RTFileUnlock(RTFILE hFile, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    fl.l_type   = F_UNLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    if (fcntl(RTFileToNative(hFile), F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+
+    int iErr = errno;
+    if (iErr == ENOTSUP)
+    {
+        /* A SMB hack, see RTFileLock. */
+        if (!flock(RTFileToNative(hFile), LOCK_UN))
+            return VINF_SUCCESS;
+    }
+
+    /** @todo check error codes for non existing lock. */
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/krnlmod-darwin.cpp b/src/VBox/Runtime/r3/darwin/krnlmod-darwin.cpp
new file mode 100644
index 00000000..756786b0
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/krnlmod-darwin.cpp
@@ -0,0 +1,470 @@
+/* $Id: krnlmod-darwin.cpp $ */
+/** @file
+ * IPRT - Kernel module, Darwin.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/krnlmod.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/ldr.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/string.h>
+#include <iprt/types.h>
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+#include <libkern/OSReturn.h>
+
+
+/** @name Missing/private IOKitLib declarations and definitions.
+ * @{  */
+/** OSKextCopyLoadedKextInfo in IOKit. */
+typedef CFDictionaryRef (* PFNOSKEXTCOPYLOADEDKEXTINFO)(CFArrayRef, CFArrayRef);
+/** KextManagerLoadKextWithURL in IOKit. */
+typedef OSReturn (* PFNKEXTMANAGERLOADKEXTWITHURL)(CFURLRef, CFArrayRef);
+/** KextManagerLoadKextWithIdentifier in IOKit */
+typedef OSReturn (* PFNKEXTMANAGERLOADKEXTWITHIDENTIFIER)(CFStringRef, CFArrayRef);
+/** KextManagerUnloadKextWithIdentifier in IOKit */
+typedef OSReturn (* PFNKEXTMANAGERUNLOADKEXTWITHIDENTIFIER)(CFStringRef);
+
+#ifndef kOSBundleRetainCountKey
+# define kOSBundleRetainCountKey CFSTR("OSBundleRetainCount")
+#endif
+#ifndef kOSBundleLoadSizeKey
+# define kOSBundleLoadSizeKey CFSTR("OSBundleLoadSize")
+#endif
+#ifndef kOSBundleLoadAddressKey
+# define kOSBundleLoadAddressKey CFSTR("OSBundleLoadAddress")
+#endif
+/** @} */
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Internal kernel information record state.
+ */
+typedef struct RTKRNLMODINFOINT
+{
+    /** Reference counter. */
+    volatile uint32_t   cRefs;
+    /** The dictionary containing our data. */
+    CFDictionaryRef     hDictKext;
+} RTKRNLMODINFOINT;
+/** Pointer to the internal kernel module information record. */
+typedef RTKRNLMODINFOINT *PRTKRNLMODINFOINT;
+/** Pointer to a const internal kernel module information record. */
+typedef const RTKRNLMODINFOINT *PCRTKRNLMODINFOINT;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static RTONCE                                 g_GetIoKitApisOnce = RTONCE_INITIALIZER;
+static PFNOSKEXTCOPYLOADEDKEXTINFO            g_pfnOSKextCopyLoadedKextInfo = NULL;
+static PFNKEXTMANAGERLOADKEXTWITHURL          g_pfnKextManagerLoadKextWithUrl = NULL;
+static PFNKEXTMANAGERLOADKEXTWITHIDENTIFIER   g_pfnKextManagerLoadKextWithIdentifier = NULL;
+static PFNKEXTMANAGERUNLOADKEXTWITHIDENTIFIER g_pfnKextManagerUnloadKextWithIdentifier = NULL;
+
+/** Do-once callback for setting g_pfnOSKextCopyLoadedKextInfo.   */
+static DECLCALLBACK(int) rtKrnlModDarwinResolveIoKitApis(void *pvUser)
+{
+    RTLDRMOD hMod;
+//    int rc = RTLdrLoad("/System/Library/Frameworks/IOKit.framework/Versions/Current/IOKit", &hMod);
+    int rc = RTLdrLoadEx("/System/Library/Frameworks/IOKit.framework/Versions/Current/IOKit", &hMod, RTLDRLOAD_FLAGS_NO_SUFFIX, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        RTLdrGetSymbol(hMod, "OSKextCopyLoadedKextInfo",  (void **)&g_pfnOSKextCopyLoadedKextInfo);
+        RTLdrGetSymbol(hMod, "KextManagerLoadKextWithURL",  (void **)&g_pfnKextManagerLoadKextWithUrl);
+        RTLdrGetSymbol(hMod, "KextManagerLoadKextWithIdentifier",  (void **)&g_pfnKextManagerLoadKextWithIdentifier);
+        RTLdrGetSymbol(hMod, "KextManagerUnloadKextWithIdentifier",  (void **)&g_pfnKextManagerUnloadKextWithIdentifier);
+    }
+
+    RT_NOREF(pvUser);
+    return VINF_SUCCESS;
+}
+
+/**
+ * Returns the kext information dictionary structure matching the given name.
+ *
+ * @returns Pointer to the matching module information record on success or NULL if not found.
+ * @param   pszName          The name to look for.
+ */
+static CFDictionaryRef rtKrnlModDarwinGetKextInfoByName(const char *pszName)
+{
+    CFDictionaryRef hDictKext = NULL;
+
+    RTOnce(&g_GetIoKitApisOnce, rtKrnlModDarwinResolveIoKitApis, NULL);
+    if (g_pfnOSKextCopyLoadedKextInfo)
+    {
+        CFStringRef hKextName = CFStringCreateWithCString(kCFAllocatorDefault, pszName, kCFStringEncodingUTF8);
+        if (hKextName)
+        {
+            CFArrayRef hArrKextIdRef = CFArrayCreate(kCFAllocatorDefault, (const void **)&hKextName, 1, &kCFTypeArrayCallBacks);
+            if (hArrKextIdRef)
+            {
+                CFDictionaryRef hLoadedKexts = g_pfnOSKextCopyLoadedKextInfo(hArrKextIdRef, NULL /* all info */);
+                if (hLoadedKexts)
+                {
+                    if (CFDictionaryGetCount(hLoadedKexts) > 0)
+                    {
+                        hDictKext = (CFDictionaryRef)CFDictionaryGetValue(hLoadedKexts, hKextName);
+                        CFRetain(hDictKext);
+                    }
+
+                    CFRelease(hLoadedKexts);
+                }
+                CFRelease(hArrKextIdRef);
+            }
+            CFRelease(hKextName);
+        }
+    }
+
+    return hDictKext;
+}
+
+/**
+ * Destroy the given kernel module information record.
+ *
+ * @param   pThis            The record to destroy.
+ */
+static void rtKrnlModInfoDestroy(PRTKRNLMODINFOINT pThis)
+{
+    CFRelease(pThis->hDictKext);
+    RTMemFree(pThis);
+}
+
+
+RTDECL(int) RTKrnlModQueryLoaded(const char *pszName, bool *pfLoaded)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfLoaded, VERR_INVALID_POINTER);
+
+    CFDictionaryRef hDictKext = rtKrnlModDarwinGetKextInfoByName(pszName);
+    *pfLoaded = hDictKext != NULL;
+    if (hDictKext)
+        CFRelease(hDictKext);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfo(const char *pszName, PRTKRNLMODINFO phKrnlModInfo)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(phKrnlModInfo, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    CFDictionaryRef hDictKext = rtKrnlModDarwinGetKextInfoByName(pszName);
+    if (hDictKext)
+    {
+        PRTKRNLMODINFOINT pThis = (PRTKRNLMODINFOINT)RTMemAllocZ(sizeof(RTKRNLMODINFOINT));
+        if (pThis)
+        {
+            pThis->cRefs     = 1;
+            pThis->hDictKext = hDictKext;
+
+            *phKrnlModInfo = pThis;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    else
+        rc = VERR_NOT_FOUND;
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModLoadedGetCount(void)
+{
+    uint32_t cLoadedKexts = 0;
+    RTOnce(&g_GetIoKitApisOnce, rtKrnlModDarwinResolveIoKitApis, NULL);
+    if (g_pfnOSKextCopyLoadedKextInfo)
+    {
+        CFDictionaryRef hLoadedKexts = g_pfnOSKextCopyLoadedKextInfo(NULL, NULL /* all info */);
+        if (hLoadedKexts)
+        {
+            cLoadedKexts = CFDictionaryGetCount(hLoadedKexts);
+            CFRelease(hLoadedKexts);
+        }
+    }
+
+    return cLoadedKexts;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfoAll(PRTKRNLMODINFO pahKrnlModInfo, uint32_t cEntriesMax,
+                                        uint32_t *pcEntries)
+{
+    if (cEntriesMax > 0)
+        AssertPtrReturn(pahKrnlModInfo, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    RTOnce(&g_GetIoKitApisOnce, rtKrnlModDarwinResolveIoKitApis, NULL);
+    if (g_pfnOSKextCopyLoadedKextInfo)
+    {
+        CFDictionaryRef hLoadedKexts = g_pfnOSKextCopyLoadedKextInfo(NULL, NULL /* all info */);
+        if (hLoadedKexts)
+        {
+            uint32_t cLoadedKexts = CFDictionaryGetCount(hLoadedKexts);
+            if (cLoadedKexts <= cEntriesMax)
+            {
+                CFDictionaryRef *pahDictKext = (CFDictionaryRef *)RTMemTmpAllocZ(cLoadedKexts * sizeof(CFDictionaryRef));
+                if (pahDictKext)
+                {
+                    CFDictionaryGetKeysAndValues(hLoadedKexts, NULL, (const void **)pahDictKext);
+                    for (uint32_t i = 0; i < cLoadedKexts; i++)
+                    {
+                        PRTKRNLMODINFOINT pThis = (PRTKRNLMODINFOINT)RTMemAllocZ(sizeof(RTKRNLMODINFOINT));
+                        if (RT_LIKELY(pThis))
+                        {
+                            pThis->cRefs = 1;
+                            pThis->hDictKext = pahDictKext[i];
+                            CFRetain(pThis->hDictKext);
+                            pahKrnlModInfo[i] = pThis;
+                        }
+                        else
+                        {
+                            rc = VERR_NO_MEMORY;
+                            /* Rollback. */
+                            while (i-- > 0)
+                            {
+                                CFRelease(pahKrnlModInfo[i]->hDictKext);
+                                RTMemFree(pahKrnlModInfo[i]);
+                            }
+                        }
+                    }
+
+                    if (   RT_SUCCESS(rc)
+                        && pcEntries)
+                        *pcEntries = cLoadedKexts;
+
+                    RTMemTmpFree(pahDictKext);
+                }
+                else
+                    rc = VERR_NO_MEMORY;
+            }
+            else
+            {
+                rc = VERR_BUFFER_OVERFLOW;
+
+                if (pcEntries)
+                    *pcEntries = cLoadedKexts;
+            }
+
+            CFRelease(hLoadedKexts);
+        }
+        else
+            rc = VERR_NOT_SUPPORTED;
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRetain(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRelease(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    if (!pThis)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtKrnlModInfoDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoGetRefCnt(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    uint32_t cRefCnt = 0;
+    CFNumberRef hRetainCnt = (CFNumberRef)CFDictionaryGetValue(pThis->hDictKext,
+                                                               kOSBundleRetainCountKey);
+    if (hRetainCnt)
+        CFNumberGetValue(hRetainCnt, kCFNumberSInt32Type, &cRefCnt);
+
+    return cRefCnt;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetName(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    const char *pszName = NULL;
+    CFStringRef hBundleId = (CFStringRef)CFDictionaryGetValue(pThis->hDictKext,
+                                                              kCFBundleIdentifierKey);
+    if (hBundleId)
+        pszName = CFStringGetCStringPtr(hBundleId, kCFStringEncodingUTF8);
+
+    return pszName;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetFilePath(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return NULL;
+}
+
+
+RTDECL(size_t) RTKrnlModInfoGetSize(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    size_t cbKrnlMod = 0;
+    CFNumberRef hKrnlModSize = (CFNumberRef)CFDictionaryGetValue(pThis->hDictKext,
+                                                                 kOSBundleLoadSizeKey);
+    if (hKrnlModSize)
+    {
+        uint32_t cbTmp = 0;
+        CFNumberGetValue(hKrnlModSize, kCFNumberSInt32Type, &cbTmp);
+        cbKrnlMod = cbTmp;
+    }
+
+    return cbKrnlMod;
+}
+
+
+RTDECL(RTR0UINTPTR) RTKrnlModInfoGetLoadAddr(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    RTR0UINTPTR uKrnlModLoadAddr = 0;
+    CFNumberRef hKrnlModLoadAddr = (CFNumberRef)CFDictionaryGetValue(pThis->hDictKext,
+                                                                     kOSBundleLoadAddressKey);
+    if (hKrnlModLoadAddr)
+    {
+        uint64_t uAddrTmp = 0;
+        CFNumberGetValue(hKrnlModLoadAddr, kCFNumberSInt64Type, &uAddrTmp);
+        uKrnlModLoadAddr = uAddrTmp;
+    }
+
+    return uKrnlModLoadAddr;
+}
+
+
+RTDECL(int) RTKrnlModInfoQueryRefModInfo(RTKRNLMODINFO hKrnlModInfo, uint32_t idx,
+                                         PRTKRNLMODINFO phKrnlModInfoRef)
+{
+    RT_NOREF3(hKrnlModInfo, idx, phKrnlModInfoRef);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    RTOnce(&g_GetIoKitApisOnce, rtKrnlModDarwinResolveIoKitApis, NULL);
+    if (!g_pfnKextManagerLoadKextWithIdentifier) return VERR_NOT_SUPPORTED;
+
+    int rc = VINF_SUCCESS;
+    CFStringRef hKextName = CFStringCreateWithCString(kCFAllocatorDefault, pszName, kCFStringEncodingUTF8);
+    if (hKextName)
+    {
+        OSReturn rcOsx = g_pfnKextManagerLoadKextWithIdentifier(hKextName, NULL /*dependencyKextAndFolderURLs*/);
+        if (rcOsx != kOSReturnSuccess)
+            rc = VERR_NOT_SUPPORTED; /** @todo Convert OSReturn values. */
+        CFRelease(hKextName);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModLoadByPath(const char *pszPath)
+{
+    AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModUnloadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    RTOnce(&g_GetIoKitApisOnce, rtKrnlModDarwinResolveIoKitApis, NULL);
+    if (!g_pfnKextManagerUnloadKextWithIdentifier) return VERR_NOT_SUPPORTED;
+
+    int rc = VINF_SUCCESS;
+    CFStringRef hKextName = CFStringCreateWithCString(kCFAllocatorDefault, pszName, kCFStringEncodingUTF8);
+    if (hKextName)
+    {
+        OSReturn rcOsx = g_pfnKextManagerUnloadKextWithIdentifier(hKextName);
+        if (rcOsx != kOSReturnSuccess)
+            rc = VERR_NOT_SUPPORTED; /** @todo Convert OSReturn values. */
+        CFRelease(hKextName);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/darwin/mp-darwin.cpp b/src/VBox/Runtime/r3/darwin/mp-darwin.cpp
new file mode 100644
index 00000000..75c5433e
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/mp-darwin.cpp
@@ -0,0 +1,435 @@
+/* $Id: mp-darwin.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, Darwin.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT /*RTLOGGROUP_SYSTEM*/
+#include <iprt/types.h>
+
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/sysctl.h>
+#include <sys/stat.h>
+#include <sys/fcntl.h>
+#include <errno.h>
+#include <mach/mach.h>
+
+#include <CoreFoundation/CFBase.h>
+#include <IOKit/IOKitLib.h>
+/*#include <IOKit/IOBSD.h>
+#include <IOKit/storage/IOStorageDeviceCharacteristics.h>
+#include <IOKit/storage/IOBlockStorageDevice.h>
+#include <IOKit/storage/IOMedia.h>
+#include <IOKit/storage/IOCDMedia.h>
+#include <IOKit/scsi/SCSITaskLib.h>
+#include <SystemConfiguration/SystemConfiguration.h>
+#include <mach/mach_error.h>
+#include <sys/param.h>
+#include <paths.h>*/
+
+#include <iprt/mp.h>
+#include <iprt/assert.h>
+#include <iprt/cpuset.h>
+#include <iprt/log.h>
+#include <iprt/string.h>
+
+
+/**
+ * Internal worker that determines the max possible logical CPU count (hyperthreads).
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpDarwinMaxLogicalCpus(void)
+{
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctlbyname("hw.logicalcpu_max", &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+    AssertFailed();
+    return 1;
+}
+
+/**
+ * Internal worker that determines the max possible physical core count.
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpDarwinMaxPhysicalCpus(void)
+{
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctlbyname("hw.physicalcpu_max", &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+    AssertFailed();
+    return 1;
+}
+
+
+#if 0 /* unused */
+/**
+ * Internal worker that determines the current number of logical CPUs (hyperthreads).
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpDarwinOnlineLogicalCpus(void)
+{
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctlbyname("hw.logicalcpu", &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+    AssertFailed();
+    return 1;
+}
+#endif /* unused */
+
+
+/**
+ * Internal worker that determines the current number of physical CPUs.
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpDarwinOnlinePhysicalCpus(void)
+{
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctlbyname("hw.physicalcpu", &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+    AssertFailed();
+    return 1;
+}
+
+
+#if defined(RT_ARCH_ARM64)
+RTDECL(RTCPUID) RTMpCpuId(void)
+{
+    /* xnu-7195.50.7.100.1/osfmk/arm64/start.s and machine_routines.c sets TPIDRRO_EL0
+       to the cpu_data_t::cpu_id value. */
+    uint64_t u64Ret;
+    __asm__ __volatile__("mrs %0,TPIDRRO_EL0\n\t" : "=r" (u64Ret));
+    return (RTCPUID)u64Ret;
+}
+#elif defined(RT_ARCH_ARM32)
+RTDECL(RTCPUID) RTMpCpuId(void)
+{
+    /* xnu-7195.50.7.100.1/osfmk/arm/start.s and machine_routines.c sets TPIDRURO
+       to the cpu_data_t::cpu_id value. */
+    uint32_t u32Ret;
+    __asm__ __volatile__("mrs p15, 0, %0, c13, c0, 3\n\t" : "=r" (u32Ret));
+    return (RTCPUID)u32Ret;
+}
+#endif
+
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    return idCpu < RTCPUSET_MAX_CPUS && idCpu < rtMpDarwinMaxLogicalCpus() ? idCpu : -1;
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    return (unsigned)iCpu < rtMpDarwinMaxLogicalCpus() ? iCpu : NIL_RTCPUID;
+}
+
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    return rtMpDarwinMaxLogicalCpus() - 1;
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+#if 0
+    return RTMpIsCpuPossible(idCpu);
+#else
+    /** @todo proper ring-3 support on darwin, see @bugref{3014}. */
+    natural_t              cCpus;
+    processor_basic_info_t paInfo;
+    mach_msg_type_number_t cInfo;
+    kern_return_t krc = host_processor_info(mach_host_self(), PROCESSOR_BASIC_INFO,
+                                            &cCpus, (processor_info_array_t*)&paInfo, &cInfo);
+    AssertReturn(krc == KERN_SUCCESS, true);
+    bool const fIsOnline = idCpu < cCpus ? paInfo[idCpu].running : false;
+    vm_deallocate(mach_task_self(), (vm_address_t)paInfo, cInfo * sizeof(paInfo[0]));
+    return fIsOnline;
+#endif
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    return idCpu != NIL_RTCPUID
+        && idCpu < rtMpDarwinMaxLogicalCpus();
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+#if 0
+    RTCPUID cCpus = rtMpDarwinMaxLogicalCpus();
+    return RTCpuSetFromU64(RT_BIT_64(cCpus) - 1);
+
+#else
+    RTCpuSetEmpty(pSet);
+    RTCPUID cMax = rtMpDarwinMaxLogicalCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuPossible(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+#endif
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    return rtMpDarwinMaxLogicalCpus();
+}
+
+
+RTDECL(RTCPUID) RTMpGetCoreCount(void)
+{
+    return rtMpDarwinMaxPhysicalCpus();
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+#if 0
+    RTCPUID cMax = rtMpDarwinMaxLogicalCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuOnline(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+#else
+    natural_t              cCpus  = 0;
+    processor_basic_info_t paInfo = NULL;
+    mach_msg_type_number_t cInfo  = 0;
+    kern_return_t krc = host_processor_info(mach_host_self(), PROCESSOR_BASIC_INFO,
+                                            &cCpus, (processor_info_array_t *)&paInfo, &cInfo);
+    AssertReturn(krc == KERN_SUCCESS, pSet);
+
+    AssertStmt(cCpus <= RTCPUSET_MAX_CPUS, cCpus = RTCPUSET_MAX_CPUS);
+    for (natural_t idCpu = 0; idCpu < cCpus; idCpu++)
+        if (paInfo[idCpu].running)
+            RTCpuSetAdd(pSet, idCpu);
+
+    vm_deallocate(mach_task_self(), (vm_address_t)paInfo, cInfo * sizeof(paInfo[0]));
+#endif
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+    RTCPUSET Set;
+    RTMpGetOnlineSet(&Set);
+    return RTCpuSetCount(&Set);
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCoreCount(void)
+{
+    return rtMpDarwinOnlinePhysicalCpus();
+}
+
+
+RTDECL(uint32_t) RTMpGetCurFrequency(RTCPUID idCpu)
+{
+    /** @todo figure out how to get the current cpu speed on darwin. Have to
+     *  check what powermanagement does.  The powermetrics uses a private
+     *  IOReportXxxx interface and *seems* (guessing) to calculate the frequency
+     *  based on the frequency distribution over the last report period...  This
+     *  means that it's not really an suitable API for here.  */
+    NOREF(idCpu);
+    return 0;
+}
+
+
+/**
+ * Worker for RTMpGetMaxFrequency.
+ * @returns Non-zero frequency in MHz on success, 0 on failure.
+ */
+static uint32_t rtMpDarwinGetMaxFrequencyFromIOService(io_service_t hCpu)
+{
+    io_struct_inband_t  Buf = {0};
+    uint32_t            cbActual = sizeof(Buf);
+    kern_return_t krc = IORegistryEntryGetProperty(hCpu, "clock-frequency", Buf, &cbActual);
+    Log2(("rtMpDarwinGetMaxFrequencyFromIOService: krc=%d; cbActual=%#x %.16Rhxs\n", krc, cbActual, Buf));
+    if (krc == kIOReturnSuccess)
+    {
+        switch (cbActual)
+        {
+            case sizeof(uint32_t):
+                return RT_BE2H_U32(*(uint32_t *)Buf) / 1000;
+            case sizeof(uint64_t):
+                AssertFailed();
+                return RT_BE2H_U64(*(uint64_t *)Buf) / 1000;
+            default:
+                AssertFailed();
+        }
+    }
+    return 0;
+}
+
+
+RTDECL(uint32_t) RTMpGetMaxFrequency(RTCPUID idCpu)
+{
+    if (!RTMpIsCpuOnline(idCpu))
+        return 0;
+
+    /*
+     * Try the 'hw.cpufrequency_max' one.
+     */
+    uint64_t CpuFrequencyMax = 0;
+    size_t cb = sizeof(CpuFrequencyMax);
+    int rc = sysctlbyname("hw.cpufrequency_max", &CpuFrequencyMax, &cb, NULL, 0);
+    if (!rc)
+        return (CpuFrequencyMax + 999999) / 1000000;
+
+    /*
+     * Use the deprecated one.
+     */
+    int aiMib[2];
+    aiMib[0] = CTL_HW;
+    aiMib[1] = HW_CPU_FREQ;
+    int iDeprecatedFrequency = -1;
+    cb = sizeof(iDeprecatedFrequency);
+    rc = sysctl(aiMib, RT_ELEMENTS(aiMib), &iDeprecatedFrequency, &cb, NULL, 0);
+    if (rc != -1 && iDeprecatedFrequency >= 1)
+        return iDeprecatedFrequency;
+
+    /*
+     * The above does not work for Apple M1 / xnu 20.1.0, so go look at the I/O registry instead.
+     *
+     * A sample ARM layout:
+     *  | +-o cpu1@1  <class IOPlatformDevice, id 0x100000110, registered, matched, active, busy 0 (182 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x10000021b, registered, matched, active, busy 0 (1 ms), retain 6>
+     *  | +-o cpu2@2  <class IOPlatformDevice, id 0x100000111, registered, matched, active, busy 0 (175 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x10000021c, registered, matched, active, busy 0 (3 ms), retain 6>
+     *  | +-o cpu3@3  <class IOPlatformDevice, id 0x100000112, registered, matched, active, busy 0 (171 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x10000021d, registered, matched, active, busy 0 (1 ms), retain 6>
+     *  | +-o cpu4@100  <class IOPlatformDevice, id 0x100000113, registered, matched, active, busy 0 (171 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x10000021e, registered, matched, active, busy 0 (1 ms), retain 6>
+     *  | +-o cpu5@101  <class IOPlatformDevice, id 0x100000114, registered, matched, active, busy 0 (179 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x10000021f, registered, matched, active, busy 0 (9 ms), retain 6>
+     *  | +-o cpu6@102  <class IOPlatformDevice, id 0x100000115, registered, matched, active, busy 0 (172 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x100000220, registered, matched, active, busy 0 (1 ms), retain 6>
+     *  | +-o cpu7@103  <class IOPlatformDevice, id 0x100000116, registered, matched, active, busy 0 (175 ms), retain 8>
+     *  | | +-o AppleARMCPU  <class AppleARMCPU, id 0x100000221, registered, matched, active, busy 0 (5 ms), retain 6>
+     *  | +-o cpus  <class IOPlatformDevice, id 0x10000010e, registered, matched, active, busy 0 (12 ms), retain 15>
+     *
+     */
+
+#if 1 /* simpler way to get at it inspired by powermetrics, this is also used
+         in the arm version of RTMpGetDescription. */
+    /* Assume names on the form "cpu<N>" are only for CPUs. */
+    char szCpuPath[64];
+# if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+    RTStrPrintf(szCpuPath, sizeof(szCpuPath), "IODeviceTree:/cpus/CPU%X", idCpu);
+# else
+    RTStrPrintf(szCpuPath, sizeof(szCpuPath), "IODeviceTree:/cpus/cpu%x", idCpu); /** @todo Hex? M1 Max only has 10 cores... */
+# endif
+    io_registry_entry_t hIoRegEntry = IORegistryEntryFromPath(kIOMasterPortDefault, szCpuPath);
+    if (hIoRegEntry != MACH_PORT_NULL)
+    {
+        uint32_t uCpuFrequency = rtMpDarwinGetMaxFrequencyFromIOService(hIoRegEntry);
+        IOObjectRelease(hIoRegEntry);
+        if (uCpuFrequency)
+            return uCpuFrequency;
+    }
+
+#else
+    /* Assume names on the form "cpu<N>" are only for CPUs. */
+    char szCpuName[32];
+    RTStrPrintf(szCpuName, sizeof(szCpuName), "cpu%u", idCpu);
+    CFMutableDictionaryRef hMatchingDict = IOServiceNameMatching(szCpuName);
+    AssertReturn(hMatchingDict, 0);
+
+    /* Just get the first one. */
+    io_object_t hCpu = IOServiceGetMatchingService(kIOMasterPortDefault, hMatchingDict);
+    if (hCpu != 0)
+    {
+        uint32_t uCpuFrequency = rtMpDarwinGetMaxFrequencyFromIOService(hCpu);
+        IOObjectRelease(hCpu);
+        if (uCpuFrequency)
+            return uCpuFrequency;
+    }
+
+# if 1 /* Just in case... */
+    /* Create a matching dictionary for searching for CPU services in the IOKit. */
+#  if defined(RT_ARCH_ARM64) || defined(RT_ARCH_ARM32)
+    hMatchingDict = IOServiceMatching("AppleARMCPU");
+#  elif defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+    hMatchingDict = IOServiceMatching("AppleACPICPU");
+#  else
+#   error "Port me!"
+#  endif
+    AssertReturn(hMatchingDict, 0);
+
+    /* Perform the search and get a collection of Apple CPU services. */
+    io_iterator_t hCpuServices = IO_OBJECT_NULL;
+    IOReturn irc = IOServiceGetMatchingServices(kIOMasterPortDefault, hMatchingDict, &hCpuServices);
+    AssertMsgReturn(irc == kIOReturnSuccess, ("irc=%d\n", irc), 0);
+    hMatchingDict = NULL; /* the reference is consumed by IOServiceGetMatchingServices. */
+
+    /* Enumerate the matching services. */
+    uint32_t    uCpuFrequency = 0;
+    io_object_t hCurCpu;
+    while (uCpuFrequency == 0 && (hCurCpu = IOIteratorNext(hCpuServices)) != IO_OBJECT_NULL)
+    {
+        io_object_t hParent = (io_object_t)0;
+        irc = IORegistryEntryGetParentEntry(hCurCpu, kIOServicePlane, &hParent);
+        if (irc == kIOReturnSuccess && hParent)
+        {
+            uCpuFrequency = rtMpDarwinGetMaxFrequencyFromIOService(hParent);
+            IOObjectRelease(hParent);
+        }
+        IOObjectRelease(hCurCpu);
+    }
+    IOObjectRelease(hCpuServices);
+# endif
+#endif
+    AssertFailed();
+    return 0;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/pathhost-darwin.cpp b/src/VBox/Runtime/r3/darwin/pathhost-darwin.cpp
new file mode 100644
index 00000000..58bcd1ec
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/pathhost-darwin.cpp
@@ -0,0 +1,117 @@
+/* $Id: pathhost-darwin.cpp $ */
+/** @file
+ * IPRT - Path Conversions, Darwin.
+ *
+ * On darwin path names on the disk are decomposed using normalization
+ * form D (NFD).  Since this behavior is unique for the Mac, we will precompose
+ * the path name strings we get from the XNU kernel.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include "internal/iprt.h"
+
+#include "internal/path.h"
+
+
+int rtPathToNative(const char **ppszNativePath, const char *pszPath, const char *pszBasePath)
+{
+    /** @todo We should decompose the string here, but the file system will do
+     *        that for us if we don't, so why bother. */
+    *ppszNativePath = (char *)pszPath;
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return VINF_SUCCESS;
+}
+
+
+void rtPathFreeNative(char const *pszNativePath, const char *pszPath)
+{
+    Assert(pszNativePath == pszPath || !pszNativePath);
+    NOREF(pszNativePath);
+    NOREF(pszPath);
+}
+
+
+int rtPathFromNative(char const **ppszPath, const char *pszNativePath, const char *pszBasePath)
+{
+    /** @todo We must compose the codepoints in the string here.  We get file names
+     *        in normalization form D so we'll end up with normalization form C
+     *        whatever approach we take. */
+    int rc = RTStrValidateEncodingEx(pszNativePath, RTSTR_MAX, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+        *ppszPath = pszNativePath;
+    else
+        *ppszPath = NULL;
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
+
+void rtPathFreeIprt(const char *pszPath, const char *pszNativePath)
+{
+    Assert(pszPath == pszNativePath || !pszPath);
+    NOREF(pszPath); NOREF(pszNativePath);
+}
+
+
+int rtPathFromNativeCopy(char *pszPath, size_t cbPath, const char *pszNativePath, const char *pszBasePath)
+{
+    /** @todo We must compose the codepoints in the string here.  We get file names
+     *        in normalization form D so we'll end up with normalization form C
+     *        whatever approach we take. */
+    int rc = RTStrValidateEncodingEx(pszNativePath, RTSTR_MAX, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+        rc = RTStrCopyEx(pszPath, cbPath, pszNativePath, RTSTR_MAX);
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
+
+int rtPathFromNativeDup(char **ppszPath, const char *pszNativePath, const char *pszBasePath)
+{
+    /** @todo We must compose the codepoints in the string here.  We get file names
+     *        in normalization form D so we'll end up with normalization form C
+     *        whatever approach we take. */
+    int rc = RTStrValidateEncodingEx(pszNativePath, RTSTR_MAX, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+        rc = RTStrDupEx(ppszPath, pszNativePath);
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/rtProcInitExePath-darwin.cpp b/src/VBox/Runtime/r3/darwin/rtProcInitExePath-darwin.cpp
new file mode 100644
index 00000000..af6116eb
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/rtProcInitExePath-darwin.cpp
@@ -0,0 +1,76 @@
+/* $Id: rtProcInitExePath-darwin.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, Darwin.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#ifdef RT_OS_DARWIN
+# include <mach-o/dyld.h>
+#endif
+
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Query the image name from the dynamic linker, convert and return it.
+     */
+    const char *pszImageName = _dyld_get_image_name(0);
+    AssertReturn(pszImageName, VERR_INTERNAL_ERROR);
+
+    char szTmpPath[PATH_MAX + 1];
+    const char *psz = realpath(pszImageName, szTmpPath);
+    int rc;
+    if (psz)
+        rc = rtPathFromNativeCopy(pszPath, cchPath, szTmpPath, NULL);
+    else
+        rc = RTErrConvertFromErrno(errno);
+    AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, strlen(pszImageName), pszPath), rc);
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/sched-darwin.cpp b/src/VBox/Runtime/r3/darwin/sched-darwin.cpp
new file mode 100644
index 00000000..3e819cb0
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/sched-darwin.cpp
@@ -0,0 +1,363 @@
+/* $Id: sched-darwin.cpp $ */
+/** @file
+ * IPRT - Scheduling, Darwin.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <mach/thread_act.h>
+#include <mach/thread_policy.h>
+#include <mach/thread_info.h>
+#include <mach/host_info.h>
+#include <mach/mach_init.h>
+#include <mach/mach_host.h>
+#include <sched.h>
+#include <pthread.h>
+#include <limits.h>
+#include <errno.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include "internal/sched.h"
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Configuration of one priority.
+ */
+typedef struct
+{
+    /** The priority. */
+    RTPROCPRIORITY  enmPriority;
+    /** The name of this priority. */
+    const char     *pszName;
+    /** Array scheduler attributes corresponding to each of the thread types. */
+    struct
+    {
+        /** For sanity include the array index. */
+        RTTHREADTYPE    enmType;
+        /** The desired mach base_priority value. */
+        int             iBasePriority;
+        /** The suggested priority value. (Same as iBasePriority seems to do the
+         *  trick.) */
+        int             iPriority;
+    } aTypes[RTTHREADTYPE_END];
+} PROCPRIORITY;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Array of static priority configurations.
+ *
+ * ASSUMES that pthread_setschedparam takes a sched_priority argument in the
+ * range 0..127, which is translated into mach base_priority 0..63 and mach
+ * importance -31..32 (among other things). We also ASSUMES SCHED_OTHER.
+ *
+ * The base_priority range can be checked with tstDarwinSched, we're assuming it's
+ * 0..63 for user processes.
+ *
+ * Further we observe that fseventsd and mds both run at (mach) priority 50,
+ * while Finder runs at 47. At priority 63 we find the dynamic pager, the login
+ * window, UserEventAgent, SystemUIServer and coreaudiod. We do not wish to upset the
+ * dynamic pager, UI or audio, but we wish for I/O to not be bothered by spotlight
+ * (mds/fseventsd).
+ */
+static const PROCPRIORITY g_aPriorities[] =
+{
+    {
+        RTPROCPRIORITY_DEFAULT, "Default",
+        {
+            { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       29, 29 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       30, 30 },
+            { RTTHREADTYPE_EMULATION,               31, 31 }, /* the default priority */
+            { RTTHREADTYPE_DEFAULT,                 32, 32 },
+            { RTTHREADTYPE_GUI,                     32, 32 },
+            { RTTHREADTYPE_MAIN_WORKER,             32, 32 },
+            { RTTHREADTYPE_VRDP_IO,                 39, 39 },
+            { RTTHREADTYPE_DEBUGGER,                42, 42 },
+            { RTTHREADTYPE_MSG_PUMP,                47, 47 },
+            { RTTHREADTYPE_IO,                      52, 52 },
+            { RTTHREADTYPE_TIMER,                   55, 55 }
+        }
+    },
+    {
+        RTPROCPRIORITY_LOW, "Low",
+        {
+            { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       20, 20 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       22, 22 },
+            { RTTHREADTYPE_EMULATION,               24, 24 },
+            { RTTHREADTYPE_DEFAULT,                 28, 28 },
+            { RTTHREADTYPE_GUI,                     29, 29 },
+            { RTTHREADTYPE_MAIN_WORKER,             30, 30 },
+            { RTTHREADTYPE_VRDP_IO,                 31, 31 },
+            { RTTHREADTYPE_DEBUGGER,                31, 31 },
+            { RTTHREADTYPE_MSG_PUMP,                31, 31 },
+            { RTTHREADTYPE_IO,                      31, 31 },
+            { RTTHREADTYPE_TIMER,                   31, 31 }
+        }
+    },
+    {
+        RTPROCPRIORITY_NORMAL, "Normal",
+        {
+            { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       29, 29 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       30, 30 },
+            { RTTHREADTYPE_EMULATION,               31, 31 }, /* the default priority */
+            { RTTHREADTYPE_DEFAULT,                 32, 32 },
+            { RTTHREADTYPE_GUI,                     32, 32 },
+            { RTTHREADTYPE_MAIN_WORKER,             32, 32 },
+            { RTTHREADTYPE_VRDP_IO,                 39, 39 },
+            { RTTHREADTYPE_DEBUGGER,                42, 42 },
+            { RTTHREADTYPE_MSG_PUMP,                47, 47 },
+            { RTTHREADTYPE_IO,                      52, 52 },
+            { RTTHREADTYPE_TIMER,                   55, 55 }
+        }
+    },
+    {
+        RTPROCPRIORITY_HIGH, "High",
+        {
+            { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       30, 30 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       31, 31 },
+            { RTTHREADTYPE_EMULATION,               32, 32 },
+            { RTTHREADTYPE_DEFAULT,                 40, 40 },
+            { RTTHREADTYPE_GUI,                     41, 41 },
+            { RTTHREADTYPE_MAIN_WORKER,             43, 43 },
+            { RTTHREADTYPE_VRDP_IO,                 45, 45 },
+            { RTTHREADTYPE_DEBUGGER,                47, 47 },
+            { RTTHREADTYPE_MSG_PUMP,                49, 49 },
+            { RTTHREADTYPE_IO,                      57, 57 },
+            { RTTHREADTYPE_TIMER,                   61, 61 }
+        }
+    },
+    /* last */
+    {
+        RTPROCPRIORITY_FLAT, "Flat",
+        {
+            { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       31, 31 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       31, 31 },
+            { RTTHREADTYPE_EMULATION,               31, 31 },
+            { RTTHREADTYPE_DEFAULT,                 31, 31 },
+            { RTTHREADTYPE_GUI,                     31, 31 },
+            { RTTHREADTYPE_MAIN_WORKER,             31, 31 },
+            { RTTHREADTYPE_VRDP_IO,                 31, 31 },
+            { RTTHREADTYPE_DEBUGGER,                31, 31 },
+            { RTTHREADTYPE_MSG_PUMP,                31, 31 },
+            { RTTHREADTYPE_IO,                      31, 31 },
+            { RTTHREADTYPE_TIMER,                   31, 31 }
+        }
+    },
+};
+
+
+/**
+ * The dynamic default priority configuration.
+ *
+ * This can be recalulated at runtime depending on what the
+ * system allow us to do. Presently we don't do this as it seems
+ * Darwin generally lets us do whatever we want.
+ *
+ * @remarks this is the same as "Normal" above.
+ */
+static PROCPRIORITY g_aDefaultPriority =
+{
+    RTPROCPRIORITY_DEFAULT, "Default",
+    {
+        { RTTHREADTYPE_INVALID,                 INT_MIN, INT_MIN },
+        { RTTHREADTYPE_INFREQUENT_POLLER,       29, 29 },
+        { RTTHREADTYPE_MAIN_HEAVY_WORKER,       30, 30 },
+        { RTTHREADTYPE_EMULATION,               31, 31 }, /* the default priority */
+        { RTTHREADTYPE_DEFAULT,                 32, 32 },
+        { RTTHREADTYPE_GUI,                     32, 32 },
+        { RTTHREADTYPE_MAIN_WORKER,             32, 32 },
+        { RTTHREADTYPE_VRDP_IO,                 39, 39 },
+        { RTTHREADTYPE_DEBUGGER,                42, 42 },
+        { RTTHREADTYPE_MSG_PUMP,                47, 47 },
+        { RTTHREADTYPE_IO,                      52, 52 },
+        { RTTHREADTYPE_TIMER,                   55, 55 }
+    }
+};
+
+
+/** Pointer to the current priority configuration. */
+static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
+
+
+/**
+ * Get's the priority information for the current thread.
+ *
+ * @returns The base priority
+ * @param   pThread     The thread to get it for.  NULL for current.
+ */
+static int rtSchedDarwinGetBasePriority(PRTTHREADINT pThread)
+{
+    /* the base_priority. */
+    mach_msg_type_number_t       Count  = POLICY_TIMESHARE_INFO_COUNT;
+    struct policy_timeshare_info TSInfo = {0,0,0,0,0};
+    kern_return_t krc = thread_info(!pThread ? mach_thread_self() : pthread_mach_thread_np((pthread_t)pThread->Core.Key),
+                                    THREAD_SCHED_TIMESHARE_INFO, (thread_info_t)&TSInfo, &Count);
+    Assert(krc == KERN_SUCCESS); NOREF(krc);
+
+    return TSInfo.base_priority;
+}
+
+
+DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+
+    /*
+     * Get the current priority.
+     */
+    int iBasePriority = rtSchedDarwinGetBasePriority(NULL);
+    Assert(iBasePriority >= 0 && iBasePriority <= 63);
+
+    /*
+     * If it doesn't match the default, select the closest one from the table.
+     */
+    int offBest = RT_ABS(g_pProcessPriority->aTypes[enmType].iBasePriority - iBasePriority);
+    if (offBest)
+    {
+        for (unsigned i = 0; i < RT_ELEMENTS(g_aPriorities); i++)
+        {
+            int off = RT_ABS(g_aPriorities[i].aTypes[enmType].iBasePriority - iBasePriority);
+            if (off < offBest)
+            {
+                g_pProcessPriority = &g_aPriorities[i];
+                if (!off)
+                    break;
+                offBest = off;
+            }
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
+{
+    Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
+
+    /*
+     * No checks necessary, we assume we can set any priority in the user process range.
+     */
+    const PROCPRIORITY *pProcessPriority = &g_aDefaultPriority;
+    for (unsigned i = 0; i < RT_ELEMENTS(g_aPriorities); i++)
+        if (g_aPriorities[i].enmPriority == enmPriority)
+        {
+            pProcessPriority = &g_aPriorities[i];
+            break;
+        }
+    Assert(pProcessPriority != &g_aDefaultPriority);
+    ASMAtomicUoWritePtr(&g_pProcessPriority, pProcessPriority);
+
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    AssertMsg(g_pProcessPriority && g_pProcessPriority->aTypes[enmType].enmType == enmType,
+              ("enmType=%d entry=%d\n", enmType, g_pProcessPriority->aTypes[enmType].enmType));
+
+    /*
+     * Get the current policy and params first since there are
+     * opaque members in the param structure and we don't wish to
+     * change the policy.
+     */
+    int iSchedPolicy = SCHED_OTHER;
+    struct sched_param SchedParam = {0, {0,0,0,0} };
+    int err = pthread_getschedparam((pthread_t)pThread->Core.Key, &iSchedPolicy, &SchedParam);
+    if (!err)
+    {
+        int const iDesiredBasePriority = g_pProcessPriority->aTypes[enmType].iBasePriority;
+        int       iPriority            = g_pProcessPriority->aTypes[enmType].iPriority;
+
+        /*
+         * First try with the given pthread priority number.
+         * Then make adjustments in case we missed the desired base priority (interface
+         * changed or whatever - its using an obsolete mach api).
+         */
+        SchedParam.sched_priority = iPriority;
+        err = pthread_setschedparam((pthread_t)pThread->Core.Key, iSchedPolicy, &SchedParam);
+        if (!err)
+        {
+            int i = 0;
+            int iBasePriority = rtSchedDarwinGetBasePriority(pThread);
+
+            while (   !err
+                   && iBasePriority < iDesiredBasePriority
+                   && i++ < 256)
+            {
+                SchedParam.sched_priority = ++iPriority;
+                err = pthread_setschedparam((pthread_t)pThread->Core.Key, iSchedPolicy, &SchedParam);
+                iBasePriority = rtSchedDarwinGetBasePriority(pThread);
+            }
+
+            while (   !err
+                   && iPriority > 0
+                   && iBasePriority > iDesiredBasePriority
+                   && i++ < 256)
+            {
+                SchedParam.sched_priority = --iPriority;
+                err = pthread_setschedparam((pthread_t)pThread->Core.Key, iSchedPolicy, &SchedParam);
+                iBasePriority = rtSchedDarwinGetBasePriority(pThread);
+            }
+
+            return VINF_SUCCESS;
+        }
+    }
+    int rc = RTErrConvertFromErrno(err);
+    AssertMsgRC(rc, ("rc=%Rrc err=%d iSchedPolicy=%d sched_priority=%d\n",
+                     rc, err, iSchedPolicy, SchedParam.sched_priority));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/systemmem-darwin.cpp b/src/VBox/Runtime/r3/darwin/systemmem-darwin.cpp
new file mode 100644
index 00000000..8c389d27
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/systemmem-darwin.cpp
@@ -0,0 +1,96 @@
+/* $Id: systemmem-darwin.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, darwin ring-3.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/sysctl.h>
+#include <sys/stat.h>
+#include <mach/mach.h>
+
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int aiMib[2];
+    aiMib[0] = CTL_HW;
+    aiMib[1] = HW_MEMSIZE;
+    uint64_t    cbPhysMem = UINT64_MAX;
+    size_t      cb = sizeof(cbPhysMem);
+    int rc = sysctl(aiMib, RT_ELEMENTS(aiMib), &cbPhysMem, &cb, NULL, 0);
+    if (rc == 0)
+    {
+        *pcb = cbPhysMem;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    static mach_port_t volatile s_hSelfPort = 0;
+    mach_port_t hSelfPort = s_hSelfPort;
+    if (hSelfPort == 0)
+        s_hSelfPort = hSelfPort = mach_host_self();
+
+    vm_statistics_data_t    VmStats;
+    mach_msg_type_number_t  cItems = sizeof(VmStats) / sizeof(natural_t);
+
+    kern_return_t krc = host_statistics(hSelfPort, HOST_VM_INFO, (host_info_t)&VmStats, &cItems);
+    if (krc == KERN_SUCCESS)
+    {
+        uint64_t cPages = VmStats.inactive_count;
+        cPages += VmStats.free_count;
+        *pcb = cPages * PAGE_SIZE;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromDarwin(krc);
+}
+
diff --git a/src/VBox/Runtime/r3/darwin/time-darwin.cpp b/src/VBox/Runtime/r3/darwin/time-darwin.cpp
new file mode 100644
index 00000000..bc18badd
--- /dev/null
+++ b/src/VBox/Runtime/r3/darwin/time-darwin.cpp
@@ -0,0 +1,125 @@
+/* $Id: time-darwin.cpp $ */
+/** @file
+ * IPRT - Time, Darwin.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <mach/mach_time.h>
+#include <mach/kern_return.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include <iprt/time.h>
+#include <iprt/assert.h>
+#include "internal/time.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static struct mach_timebase_info    g_Info = { 0, 0 };
+static double                       g_rdFactor = 0.0;
+static bool                         g_fFailedToGetTimeBaseInfo = false;
+
+
+/**
+ * Perform lazy init (pray we're not racing anyone in a bad way).
+ */
+static void rtTimeDarwinLazyInit(void)
+{
+    struct mach_timebase_info Info;
+    if (mach_timebase_info(&Info) == KERN_SUCCESS)
+    {
+        g_rdFactor = (double)Info.numer / (double)Info.denom;
+        g_Info = Info;
+    }
+    else
+    {
+        g_fFailedToGetTimeBaseInfo = true;
+        Assert(g_Info.denom == 0 && g_Info.numer == 0 && g_rdFactor == 0.0);
+    }
+}
+
+
+/**
+ * Internal worker.
+ * @returns Nanosecond timestamp.
+ */
+DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
+{
+    /* Lazy init. */
+    if (RT_UNLIKELY(g_Info.denom == 0 && !g_fFailedToGetTimeBaseInfo))
+        rtTimeDarwinLazyInit();
+
+    /* special case: absolute time is in nanoseconds */
+    if (g_Info.denom == 1 && g_Info.numer == 1)
+        return mach_absolute_time();
+
+    /* general case: multiply by factor to get nanoseconds. */
+    if (g_rdFactor != 0.0)
+        return mach_absolute_time() * g_rdFactor;
+
+    /* worst case: fallback to gettimeofday(). */
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return (uint64_t)tv.tv_sec  * RT_NS_1SEC_64
+         + (uint64_t)(tv.tv_usec * RT_NS_1US);
+}
+
+
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
+
+RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
+{
+    /** @todo find nanosecond API for getting time of day. */
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return RTTimeSpecSetTimeval(pTime, &tv);
+}
+
diff --git a/src/VBox/Runtime/r3/dir.cpp b/src/VBox/Runtime/r3/dir.cpp
new file mode 100644
index 00000000..02058632
--- /dev/null
+++ b/src/VBox/Runtime/r3/dir.cpp
@@ -0,0 +1,917 @@
+/* $Id: dir.cpp $ */
+/** @file
+ * IPRT - Directory Manipulation, Part 1.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/dir.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/uni.h>
+#define RTDIR_AGNOSTIC
+#include "internal/dir.h"
+#include "internal/path.h"
+
+
+static DECLCALLBACK(bool) rtDirFilterWinNtMatch(PRTDIRINTERNAL pDir, const char *pszName);
+static DECLCALLBACK(bool) rtDirFilterWinNtMatchNoWildcards(PRTDIRINTERNAL pDir, const char *pszName);
+DECLINLINE(bool) rtDirFilterWinNtMatchEon(PCRTUNICP puszFilter);
+static bool rtDirFilterWinNtMatchDosStar(unsigned iDepth, RTUNICP uc, const char *pszNext, PCRTUNICP puszFilter);
+static bool rtDirFilterWinNtMatchStar(unsigned iDepth, RTUNICP uc, const char *pszNext, PCRTUNICP puszFilter);
+static bool rtDirFilterWinNtMatchBase(unsigned iDepth, const char *pszName, PCRTUNICP puszFilter);
+
+
+
+RTDECL(int) RTDirCreateFullPath(const char *pszPath, RTFMODE fMode)
+{
+    return RTDirCreateFullPathEx(pszPath, fMode, 0);
+}
+
+
+RTDECL(int) RTDirCreateFullPathEx(const char *pszPath, RTFMODE fMode, uint32_t fFlags)
+{
+    /*
+     * Resolve the path.
+     */
+    char *pszAbsPath = RTPathAbsDup(pszPath);
+    if (!pszAbsPath)
+        return VERR_NO_TMP_MEMORY;
+
+    /*
+     * Iterate the path components making sure each of them exists.
+     */
+    /* skip volume name */
+    char *psz = &pszAbsPath[rtPathVolumeSpecLen(pszAbsPath)];
+
+    /* skip the root slash if any */
+    if (RTPATH_IS_SLASH(*psz))
+        psz++;
+
+    /* iterate over path components. */
+    int rc = VINF_SUCCESS;
+    do
+    {
+        /* the next component is NULL, stop iterating */
+        if (!*psz)
+            break;
+#if RTPATH_STYLE == RTPATH_STR_F_STYLE_DOS
+        char *psz2 = strchr(psz, '/');
+        psz = strchr(psz, RTPATH_SLASH);
+        if (psz2 && (!psz || (uintptr_t)psz2 < (uintptr_t)psz))
+            psz = psz;
+#else
+        psz = strchr(psz, RTPATH_SLASH);
+#endif
+        if (psz)
+            *psz = '\0';
+
+        /*
+         * ASSUME that RTDirCreate will return VERR_ALREADY_EXISTS and not VERR_ACCESS_DENIED in those cases
+         * where the directory exists but we don't have write access to the parent directory.
+         */
+        rc = RTDirCreate(pszAbsPath, fMode, fFlags);
+        if (rc == VERR_ALREADY_EXISTS)
+            rc = VINF_SUCCESS;
+
+        if (!psz)
+            break;
+        *psz++ = RTPATH_DELIMITER;
+    } while (RT_SUCCESS(rc));
+
+    RTStrFree(pszAbsPath);
+    return rc;
+}
+
+
+/**
+ * Filter a the filename in the against a filter.
+ *
+ * @returns true if the name matches the filter.
+ * @returns false if the name doesn't match filter.
+ * @param   pDir        The directory handle.
+ * @param   pszName     The path to match to the filter.
+ */
+static DECLCALLBACK(bool) rtDirFilterWinNtMatchNoWildcards(PRTDIRINTERNAL pDir, const char *pszName)
+{
+    /*
+     * Walk the string and compare.
+     */
+    PCRTUNICP   pucFilter = pDir->puszFilter;
+    const char *psz = pszName;
+    RTUNICP     uc;
+    do
+    {
+        int rc = RTStrGetCpEx(&psz, &uc);
+        AssertRCReturn(rc, false);
+        RTUNICP ucFilter = *pucFilter++;
+        if (    uc != ucFilter
+            &&  RTUniCpToUpper(uc) != ucFilter)
+            return false;
+    } while (uc);
+    return true;
+}
+
+
+/**
+ * Matches end of name.
+ */
+DECLINLINE(bool) rtDirFilterWinNtMatchEon(PCRTUNICP puszFilter)
+{
+    RTUNICP ucFilter;
+    while (     (ucFilter = *puszFilter) == '>'
+           ||   ucFilter == '<'
+           ||   ucFilter == '*'
+           ||   ucFilter == '"')
+        puszFilter++;
+    return !ucFilter;
+}
+
+
+/**
+ * Recursive star matching.
+ * Practically the same as normal star, except that the dos star stops
+ * when hitting the last dot.
+ *
+ * @returns true on match.
+ * @returns false on miss.
+ */
+static bool rtDirFilterWinNtMatchDosStar(unsigned iDepth, RTUNICP uc, const char *pszNext, PCRTUNICP puszFilter)
+{
+    AssertReturn(iDepth++ < 256, false);
+
+    /*
+     * If there is no dos star, we should work just like the NT star.
+     * Since that's generally faster algorithms, we jump down to there if we can.
+     */
+    const char *pszDosDot = strrchr(pszNext, '.');
+    if (!pszDosDot && uc == '.')
+        pszDosDot = pszNext - 1;
+    if (!pszDosDot)
+        return rtDirFilterWinNtMatchStar(iDepth, uc, pszNext, puszFilter);
+
+    /*
+     * Inspect the next filter char(s) until we find something to work on.
+     */
+    RTUNICP ucFilter = *puszFilter++;
+    switch (ucFilter)
+    {
+        /*
+         * The star expression is the last in the pattern.
+         * We're fine if the name ends with a dot.
+         */
+        case '\0':
+            return !pszDosDot[1];
+
+        /*
+         * Simplified by brute force.
+         */
+        case '>': /* dos question mark */
+        case '?':
+        case '*':
+        case '<': /* dos star */
+        case '"': /* dos dot */
+        {
+            puszFilter--;
+            const char *pszStart = pszNext;
+            do
+            {
+                if (rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter))
+                    return true;
+                int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+            } while ((intptr_t)pszDosDot - (intptr_t)pszNext >= -1);
+
+            /* backtrack and do the current char. */
+            pszNext = RTStrPrevCp(NULL, pszStart); AssertReturn(pszNext, false);
+            return rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter);
+        }
+
+        /*
+         * Ok, we've got zero or more characters.
+         * We'll try match starting at each occurrence of this character.
+         */
+        default:
+        {
+            if (    RTUniCpToUpper(uc) == ucFilter
+                &&  rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter))
+                return true;
+            do
+            {
+                int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+                if (    RTUniCpToUpper(uc) == ucFilter
+                    &&  rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter))
+                    return true;
+            } while ((intptr_t)pszDosDot - (intptr_t)pszNext >= -1);
+            return false;
+        }
+    }
+    /* won't ever get here! */
+}
+
+
+/**
+ * Recursive star matching.
+ *
+ * @returns true on match.
+ * @returns false on miss.
+ */
+static bool rtDirFilterWinNtMatchStar(unsigned iDepth, RTUNICP uc, const char *pszNext, PCRTUNICP puszFilter)
+{
+    AssertReturn(iDepth++ < 256, false);
+
+    /*
+     * Inspect the next filter char(s) until we find something to work on.
+     */
+    for (;;)
+    {
+        RTUNICP ucFilter = *puszFilter++;
+        switch (ucFilter)
+        {
+            /*
+             * The star expression is the last in the pattern.
+             * Cool, that means we're done!
+             */
+            case '\0':
+                return true;
+
+            /*
+             * Just in case (doubt we ever get here), just merge it with the current one.
+             */
+            case '*':
+                break;
+
+            /*
+             * Skip a fixed number of chars.
+             * Figure out how many by walking the filter ignoring '*'s.
+             */
+            case '?':
+            {
+                unsigned cQms = 1;
+                while ((ucFilter = *puszFilter) == '*' || ucFilter == '?')
+                {
+                    cQms += ucFilter == '?';
+                    puszFilter++;
+                }
+                do
+                {
+                    if (!uc)
+                        return false;
+                    int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+                } while (--cQms > 0);
+                /* done? */
+                if (!ucFilter)
+                    return true;
+                break;
+            }
+
+            /*
+             * The simple way is to try char by char and match the remaining
+             * expression. If it's trailing we're done.
+             */
+            case '>': /* dos question mark */
+            {
+                if (rtDirFilterWinNtMatchEon(puszFilter))
+                    return true;
+                const char *pszStart = pszNext;
+                do
+                {
+                    if (rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter))
+                        return true;
+                    int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+                } while (uc);
+
+                /* backtrack and do the current char. */
+                pszNext = RTStrPrevCp(NULL, pszStart); AssertReturn(pszNext, false);
+                return rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter);
+            }
+
+            /*
+             * This bugger is interesting.
+             * Time for brute force. Iterate the name char by char.
+             */
+            case '<':
+            {
+                do
+                {
+                    if (rtDirFilterWinNtMatchDosStar(iDepth, uc, pszNext, puszFilter))
+                        return true;
+                    int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+                } while (uc);
+                return false;
+            }
+
+            /*
+             * This guy matches a '.' or the end of the name.
+             * It's very simple if the rest of the filter expression also matches eon.
+             */
+            case '"':
+                if (rtDirFilterWinNtMatchEon(puszFilter))
+                    return true;
+                ucFilter = '.';
+                RT_FALL_THRU();
+
+            /*
+             * Ok, we've got zero or more characters.
+             * We'll try match starting at each occurrence of this character.
+             */
+            default:
+            {
+                do
+                {
+                    if (    RTUniCpToUpper(uc) == ucFilter
+                        &&  rtDirFilterWinNtMatchBase(iDepth, pszNext, puszFilter))
+                        return true;
+                    int rc = RTStrGetCpEx(&pszNext, &uc); AssertRCReturn(rc, false);
+                } while (uc);
+                return false;
+            }
+        }
+    } /* for (;;) */
+
+    /* won't ever get here! */
+}
+
+
+/**
+ * Filter a the filename in the against a filter.
+ *
+ * The rules are as follows:
+ *      '?'     Matches exactly one char.
+ *      '*'     Matches zero or more chars.
+ *      '<'     The dos star, matches zero or more chars except the DOS dot.
+ *      '>'     The dos question mark, matches one char, but dots and end-of-name eats them.
+ *      '"'     The dos dot, matches a dot or end-of-name.
+ *
+ * @returns true if the name matches the filter.
+ * @returns false if the name doesn't match filter.
+ * @param   iDepth      The recursion depth.
+ * @param   pszName     The path to match to the filter.
+ * @param   puszFilter  The filter string.
+ */
+static bool rtDirFilterWinNtMatchBase(unsigned iDepth, const char *pszName, PCRTUNICP puszFilter)
+{
+    AssertReturn(iDepth++ < 256, false);
+
+    /*
+     * Walk the string and match it up char by char.
+     */
+    RTUNICP uc;
+    do
+    {
+        RTUNICP ucFilter = *puszFilter++;
+        int rc = RTStrGetCpEx(&pszName, &uc); AssertRCReturn(rc, false);
+        switch (ucFilter)
+        {
+            /* Exactly one char. */
+            case '?':
+                if (!uc)
+                    return false;
+                break;
+
+            /* One char, but the dos dot and end-of-name eats '>' and '<'. */
+            case '>': /* dos ? */
+                if (!uc)
+                    return rtDirFilterWinNtMatchEon(puszFilter);
+                if (uc == '.')
+                {
+                    while ((ucFilter = *puszFilter) == '>' || ucFilter == '<')
+                        puszFilter++;
+                    if (ucFilter == '"' || ucFilter == '.')  /* not 100% sure about the last dot */
+                        ++puszFilter;
+                    else /* the does question mark doesn't match '.'s, so backtrack. */
+                        pszName = RTStrPrevCp(NULL, pszName);
+                }
+                break;
+
+            /* Match a dot or the end-of-name. */
+            case '"': /* dos '.' */
+                if (uc != '.')
+                {
+                    if (uc)
+                        return false;
+                    return rtDirFilterWinNtMatchEon(puszFilter);
+                }
+                break;
+
+            /* zero or more */
+            case '*':
+                return rtDirFilterWinNtMatchStar(iDepth, uc, pszName, puszFilter);
+            case '<': /* dos '*' */
+                return rtDirFilterWinNtMatchDosStar(iDepth, uc, pszName, puszFilter);
+
+
+            /* uppercased match */
+            default:
+            {
+                if (RTUniCpToUpper(uc) != ucFilter)
+                    return false;
+                break;
+            }
+        }
+    } while (uc);
+
+    return true;
+}
+
+
+/**
+ * Filter a the filename in the against a filter.
+ *
+ * @returns true if the name matches the filter.
+ * @returns false if the name doesn't match filter.
+ * @param   pDir        The directory handle.
+ * @param   pszName     The path to match to the filter.
+ */
+static DECLCALLBACK(bool) rtDirFilterWinNtMatch(PRTDIRINTERNAL pDir, const char *pszName)
+{
+    return rtDirFilterWinNtMatchBase(0, pszName, pDir->puszFilter);
+}
+
+
+/**
+ * Initializes a WinNt like wildcard filter.
+ *
+ * @returns Pointer to the filter function.
+ * @returns NULL if the filter doesn't filter out anything.
+ * @param   pDir        The directory handle (not yet opened).
+ */
+static PFNRTDIRFILTER rtDirFilterWinNtInit(PRTDIRINTERNAL pDir)
+{
+    /*
+     * Check for the usual * and <"< (*.* in DOS language) patterns.
+     */
+    if (    (pDir->cchFilter == 1 && pDir->pszFilter[0] == '*')
+        ||  (pDir->cchFilter == 3 && !memcmp(pDir->pszFilter, "<\".>", 3))
+        )
+        return NULL;
+
+    /*
+     * Uppercase the expression, also do a little optimizations when possible.
+     */
+    bool fHaveWildcards = false;
+    unsigned iRead = 0;
+    unsigned iWrite = 0;
+    while (iRead < pDir->cucFilter)
+    {
+        RTUNICP uc = pDir->puszFilter[iRead++];
+        if (uc == '*')
+        {
+            fHaveWildcards = true;
+            /* remove extra stars. */
+            RTUNICP uc2;
+            while ((uc2 = pDir->puszFilter[iRead + 1]) == '*')
+                iRead++;
+        }
+        else if (uc == '?' || uc == '>' || uc == '<' || uc == '"')
+            fHaveWildcards = true;
+        else
+            uc = RTUniCpToUpper(uc);
+        pDir->puszFilter[iWrite++] = uc;
+    }
+    pDir->puszFilter[iWrite] = 0;
+    pDir->cucFilter = iWrite;
+
+    return fHaveWildcards
+        ? rtDirFilterWinNtMatch
+        : rtDirFilterWinNtMatchNoWildcards;
+}
+
+
+/**
+ * Common worker for opening a directory.
+ *
+ * @returns IPRT status code.
+ * @param   phDir               Where to store the directory handle.
+ * @param   pszPath             The specified path.
+ * @param   pszFilter           Pointer to where the filter start in the path.
+ *                              NULL if no filter.
+ * @param   enmFilter           The type of filter to apply.
+ * @param   fFlags              RTDIR_F_XXX.
+ * @param   hRelativeDir        The directory @a pvNativeRelative is relative
+ *                              to, ~(uintptr_t)0 if absolute.
+ * @param   pvNativeRelative    The native relative path.  NULL if absolute or
+ *                              we're to use (consume) hRelativeDir.
+ */
+static int rtDirOpenCommon(RTDIR *phDir, const char *pszPath, const char *pszFilter, RTDIRFILTER enmFilter,
+                           uint32_t fFlags, uintptr_t hRelativeDir, void *pvNativeRelative)
+{
+    /*
+     * Expand the path.
+     *
+     * The purpose of this exercise to have the abs path around
+     * for querying extra information about the objects we list.
+     * As a sideeffect we also validate the path here.
+     *
+     * Note! The RTDIR_F_NO_ABS_PATH mess is there purely for allowing us to
+     *       work around PATH_MAX using CWD on linux and other unixy systems.
+     */
+    char  *pszAbsPath;
+    size_t cbFilter;                    /* includes '\0' (thus cb and not cch). */
+    size_t cucFilter0;                  /* includes U+0. */
+    bool   fDirSlash = false;
+    if (!pszFilter)
+    {
+        if (*pszPath != '\0')
+        {
+            const char *pszLast = strchr(pszPath, '\0') - 1;
+            if (RTPATH_IS_SLASH(*pszLast))
+                fDirSlash = true;
+        }
+
+        cbFilter = cucFilter0 = 0;
+        if (!(fFlags & RTDIR_F_NO_ABS_PATH))
+            pszAbsPath = RTPathAbsExDup(NULL, pszPath, RTPATHABS_F_ENSURE_TRAILING_SLASH);
+        else
+        {
+            size_t cchTmp = strlen(pszPath);
+            pszAbsPath = RTStrAlloc(cchTmp + 2);
+            if (pszAbsPath)
+            {
+                memcpy(pszAbsPath, pszPath, cchTmp);
+                pszAbsPath[cchTmp] = RTPATH_SLASH;
+                pszAbsPath[cchTmp + 1 - fDirSlash] = '\0';
+            }
+        }
+    }
+    else
+    {
+        cbFilter = strlen(pszFilter) + 1;
+        cucFilter0 = RTStrUniLen(pszFilter) + 1;
+
+        if (pszFilter != pszPath)
+        {
+            /* yea, I'm lazy. sue me. */
+            char *pszTmp = RTStrDup(pszPath);
+            if (!pszTmp)
+                return VERR_NO_MEMORY;
+            pszTmp[pszFilter - pszPath] = '\0';
+            if (!(fFlags & RTDIR_F_NO_ABS_PATH))
+            {
+                pszAbsPath = RTPathAbsExDup(NULL, pszTmp, RTPATHABS_F_ENSURE_TRAILING_SLASH);
+                RTStrFree(pszTmp);
+            }
+            else
+            {
+                pszAbsPath = pszTmp;
+                RTPathEnsureTrailingSeparator(pszAbsPath, strlen(pszPath) + 1);
+            }
+        }
+        else if (!(fFlags & RTDIR_F_NO_ABS_PATH))
+            pszAbsPath = RTPathAbsExDup(NULL, ".", RTPATHABS_F_ENSURE_TRAILING_SLASH);
+        else
+            pszAbsPath = RTStrDup("." RTPATH_SLASH_STR);
+        fDirSlash = true;
+    }
+    if (!pszAbsPath)
+        return VERR_NO_MEMORY;
+    Assert(strchr(pszAbsPath, '\0')[-1] == RTPATH_SLASH);
+
+    /*
+     * Allocate and initialize the directory handle.
+     *
+     * The posix definition of Data.d_name allows it to be < NAME_MAX + 1,
+     * thus the horrible ugliness here. Solaris uses d_name[1] for instance.
+     */
+    size_t const cchAbsPath      = strlen(pszAbsPath);
+    size_t const cbDir           = rtDirNativeGetStructSize(pszAbsPath);
+    size_t const cbAllocated     = cbDir
+                                 + cucFilter0 * sizeof(RTUNICP)
+                                 + cbFilter
+                                 + cchAbsPath + 1 + 4;
+    PRTDIRINTERNAL pDir = (PRTDIRINTERNAL)RTMemAllocZ(cbAllocated);
+    if (!pDir)
+    {
+        RTStrFree(pszAbsPath);
+        return VERR_NO_MEMORY;
+    }
+    uint8_t *pb = (uint8_t *)pDir + cbDir;
+
+    /* initialize it */
+    pDir->u32Magic = RTDIR_MAGIC;
+    pDir->cbSelf   = cbDir;
+    if (cbFilter)
+    {
+        pDir->puszFilter = (PRTUNICP)pb;
+        int rc2 = RTStrToUniEx(pszFilter, RTSTR_MAX, &pDir->puszFilter, cucFilter0, &pDir->cucFilter);
+        AssertRC(rc2);
+        pb += cucFilter0 * sizeof(RTUNICP);
+        pDir->pszFilter = (char *)memcpy(pb, pszFilter, cbFilter);
+        pDir->cchFilter = cbFilter - 1;
+        pb += cbFilter;
+    }
+    else
+    {
+        pDir->puszFilter = NULL;
+        pDir->cucFilter = 0;
+        pDir->pszFilter = NULL;
+        pDir->cchFilter = 0;
+    }
+    pDir->enmFilter = enmFilter;
+    switch (enmFilter)
+    {
+        default:
+        case RTDIRFILTER_NONE:
+            pDir->pfnFilter = NULL;
+            break;
+        case RTDIRFILTER_WINNT:
+            pDir->pfnFilter = rtDirFilterWinNtInit(pDir);
+            break;
+        case RTDIRFILTER_UNIX:
+            pDir->pfnFilter = NULL;
+            break;
+        case RTDIRFILTER_UNIX_UPCASED:
+            pDir->pfnFilter = NULL;
+            break;
+    }
+    pDir->cchPath       = cchAbsPath;
+    pDir->pszPath       = (char *)memcpy(pb, pszAbsPath, cchAbsPath);
+    pb[cchAbsPath]      = '\0';
+    Assert(pb - (uint8_t *)pDir + cchAbsPath + 1 <= cbAllocated);
+    pDir->pszName       = NULL;
+    pDir->cchName       = 0;
+    pDir->fFlags        = fFlags;
+    pDir->fDirSlash     = fDirSlash;
+    pDir->fDataUnread   = false;
+
+    /*
+     * Hand it over to the native part.
+     */
+    int rc = rtDirNativeOpen(pDir, hRelativeDir, pvNativeRelative);
+    if (RT_SUCCESS(rc))
+        *phDir = pDir;
+    else
+        RTMemFree(pDir);
+    RTStrFree(pszAbsPath);
+    return rc;
+}
+
+
+RTDECL(int) RTDirOpen(RTDIR *phDir, const char *pszPath)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phDir, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+
+    /*
+     * Take common cause with RTDirOpenFiltered().
+     */
+    int rc = rtDirOpenCommon(phDir, pszPath, NULL, RTDIRFILTER_NONE, 0 /*fFlags*/, ~(uintptr_t)0, NULL);
+    LogFlow(("RTDirOpen(%p:{%p}, %p:{%s}): return %Rrc\n", phDir, *phDir, pszPath, pszPath, rc));
+    return rc;
+}
+
+
+DECLHIDDEN(int) rtDirOpenRelativeOrHandle(RTDIR *phDir, const char *pszPath, RTDIRFILTER enmFilter, uint32_t fFlags,
+                                          uintptr_t hRelativeDir, void *pvNativeRelative)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phDir, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTDIR_F_VALID_MASK), VERR_INVALID_FLAGS);
+    switch (enmFilter)
+    {
+        case RTDIRFILTER_UNIX:
+        case RTDIRFILTER_UNIX_UPCASED:
+            AssertMsgFailed(("%d is not implemented!\n", enmFilter));
+            return VERR_NOT_IMPLEMENTED;
+        case RTDIRFILTER_NONE:
+        case RTDIRFILTER_WINNT:
+            break;
+        default:
+            AssertMsgFailedReturn(("%d\n", enmFilter), VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Find the last component, i.e. where the filter criteria starts and the dir name ends.
+     */
+    const char *pszFilter;
+    if (enmFilter == RTDIRFILTER_NONE)
+        pszFilter = NULL;
+    else
+    {
+        pszFilter = RTPathFilename(pszPath);
+        if (!pszFilter) /* trailing slash => directory to read => no filter. */
+            enmFilter = RTDIRFILTER_NONE;
+    }
+
+    /*
+     * Call worker common with RTDirOpen which will verify the path, allocate
+     * and initialize the handle, and finally call the backend.
+     */
+    int rc = rtDirOpenCommon(phDir, pszPath, pszFilter, enmFilter, fFlags, hRelativeDir, pvNativeRelative);
+
+    LogFlow(("RTDirOpenFiltered(%p:{%p}, %p:{%s}, %d, %#x, %p, %p): return %Rrc\n",
+             phDir,*phDir, pszPath, pszPath, enmFilter, fFlags, hRelativeDir, pvNativeRelative, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTDirOpenFiltered(RTDIR *phDir, const char *pszPath, RTDIRFILTER enmFilter, uint32_t fFlags)
+{
+    return rtDirOpenRelativeOrHandle(phDir, pszPath, enmFilter, fFlags, ~(uintptr_t)0, NULL);
+}
+
+
+RTDECL(bool) RTDirIsValid(RTDIR hDir)
+{
+    return RT_VALID_PTR(hDir)
+        && hDir->u32Magic == RTDIR_MAGIC;
+}
+
+
+RTDECL(int) RTDirFlushParent(const char *pszChild)
+{
+    char        *pszPath;
+    char        *pszPathFree = NULL;
+    size_t const cchChild    = strlen(pszChild);
+    if (cchChild < RTPATH_MAX)
+        pszPath = (char *)alloca(cchChild + 1);
+    else
+    {
+        pszPathFree = pszPath = (char *)RTMemTmpAlloc(cchChild + 1);
+        if (!pszPath)
+            return VERR_NO_TMP_MEMORY;
+    }
+    memcpy(pszPath, pszChild, cchChild);
+    pszPath[cchChild] = '\0';
+    RTPathStripFilename(pszPath);
+
+    int rc = RTDirFlush(pszPath);
+
+    if (pszPathFree)
+        RTMemTmpFree(pszPathFree);
+    return rc;
+}
+
+
+RTDECL(int) RTDirQueryUnknownTypeEx(const char *pszComposedName, bool fFollowSymlinks,
+                                    RTDIRENTRYTYPE *penmType, PRTFSOBJINFO pObjInfo)
+{
+    int rc = RTPathQueryInfoEx(pszComposedName, pObjInfo, RTFSOBJATTRADD_NOTHING,
+                               fFollowSymlinks ? RTPATH_F_FOLLOW_LINK : RTPATH_F_ON_LINK);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    if (RTFS_IS_DIRECTORY(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_DIRECTORY;
+    else if (RTFS_IS_FILE(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_FILE;
+    else if (RTFS_IS_SYMLINK(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_SYMLINK;
+    else if (RTFS_IS_FIFO(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_FIFO;
+    else if (RTFS_IS_DEV_CHAR(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_DEV_CHAR;
+    else if (RTFS_IS_DEV_BLOCK(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_DEV_BLOCK;
+    else if (RTFS_IS_SOCKET(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_SOCKET;
+    else if (RTFS_IS_WHITEOUT(pObjInfo->Attr.fMode))
+        *penmType = RTDIRENTRYTYPE_WHITEOUT;
+    else
+        *penmType = RTDIRENTRYTYPE_UNKNOWN;
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTDirQueryUnknownType(const char *pszComposedName, bool fFollowSymlinks, RTDIRENTRYTYPE *penmType)
+{
+    if (   *penmType != RTDIRENTRYTYPE_UNKNOWN
+        && (   !fFollowSymlinks
+            || *penmType != RTDIRENTRYTYPE_SYMLINK))
+        return VINF_SUCCESS;
+
+    RTFSOBJINFO ObjInfo;
+    return RTDirQueryUnknownTypeEx(pszComposedName, fFollowSymlinks, penmType, &ObjInfo);
+}
+
+
+RTDECL(bool) RTDirEntryIsStdDotLink(PRTDIRENTRY pDirEntry)
+{
+    if (pDirEntry->szName[0] != '.')
+        return false;
+    if (pDirEntry->cbName == 1)
+        return true;
+    if (pDirEntry->cbName != 2)
+        return false;
+    return pDirEntry->szName[1] == '.';
+}
+
+
+RTDECL(bool) RTDirEntryExIsStdDotLink(PCRTDIRENTRYEX pDirEntryEx)
+{
+    if (pDirEntryEx->szName[0] != '.')
+        return false;
+    if (pDirEntryEx->cbName == 1)
+        return true;
+    if (pDirEntryEx->cbName != 2)
+        return false;
+    return pDirEntryEx->szName[1] == '.';
+}
+
+
+RTDECL(int) RTDirReadExA(RTDIR hDir, PRTDIRENTRYEX *ppDirEntry, size_t *pcbDirEntry, RTFSOBJATTRADD enmAddAttr, uint32_t fFlags)
+{
+    PRTDIRENTRYEX pDirEntry  = *ppDirEntry;
+    size_t        cbDirEntry = *pcbDirEntry;
+    if (pDirEntry != NULL && cbDirEntry >= sizeof(RTDIRENTRYEX))
+    { /* likely */ }
+    else
+    {
+        Assert(pDirEntry == NULL);
+        Assert(cbDirEntry == 0);
+
+        cbDirEntry  = RT_ALIGN_Z(sizeof(RTDIRENTRYEX), 16);
+        *ppDirEntry = pDirEntry = (PRTDIRENTRYEX)RTMemTmpAlloc(cbDirEntry);
+        if (pDirEntry)
+            *pcbDirEntry = cbDirEntry;
+        else
+        {
+            *pcbDirEntry = 0;
+            return VERR_NO_TMP_MEMORY;
+        }
+    }
+
+    for (;;)
+    {
+        int rc = RTDirReadEx(hDir, pDirEntry, &cbDirEntry, enmAddAttr, fFlags);
+        if (rc != VERR_BUFFER_OVERFLOW)
+            return rc;
+
+        /* Grow the buffer. */
+        RTMemTmpFree(pDirEntry);
+        cbDirEntry = RT_MAX(RT_ALIGN_Z(cbDirEntry, 64), *pcbDirEntry + 64);
+        *ppDirEntry = pDirEntry = (PRTDIRENTRYEX)RTMemTmpAlloc(cbDirEntry);
+        if (pDirEntry)
+            *pcbDirEntry = cbDirEntry;
+        else
+        {
+            *pcbDirEntry = 0;
+            return VERR_NO_TMP_MEMORY;
+        }
+    }
+}
+
+
+RTDECL(void) RTDirReadExAFree(PRTDIRENTRYEX *ppDirEntry, size_t *pcbDirEntry)
+{
+    PRTDIRENTRYEX pDirEntry = *ppDirEntry;
+    if (pDirEntry != NULL && *pcbDirEntry >= sizeof(*pcbDirEntry))
+        RTMemTmpFree(pDirEntry);
+    else
+    {
+        Assert(pDirEntry == NULL);
+        Assert(*pcbDirEntry == 0);
+    }
+    *ppDirEntry  = NULL;
+    *pcbDirEntry = 0;
+}
+
diff --git a/src/VBox/Runtime/r3/dir2.cpp b/src/VBox/Runtime/r3/dir2.cpp
new file mode 100644
index 00000000..1f47b3ed
--- /dev/null
+++ b/src/VBox/Runtime/r3/dir2.cpp
@@ -0,0 +1,242 @@
+/* $Id: dir2.cpp $ */
+/** @file
+ * IPRT - Directory Manipulation, Part 2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/dir.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include "internal/path.h"
+
+
+/**
+ * Recursion worker for RTDirRemoveRecursive.
+ *
+ * @returns IPRT status code.
+ * @param   pszBuf              The path buffer.  Contains the abs path to the
+ *                              directory to recurse into.  Trailing slash.
+ * @param   cchDir              The length of the directory we're recursing into,
+ *                              including the trailing slash.
+ * @param   cbBuf               Size of the buffer @a pszBuf points to.
+ * @param   pDirEntry           The dir entry buffer.  (Shared to save stack.)
+ * @param   pObjInfo            The object info buffer.  (ditto)
+ * @param   fFlags              RTDIRRMREC_F_XXX.
+ */
+static int rtDirRemoveRecursiveSub(char *pszBuf, size_t cchDir, size_t cbBuf, PRTDIRENTRY pDirEntry, PRTFSOBJINFO pObjInfo,
+                                   uint32_t fFlags)
+{
+    AssertReturn(RTPATH_IS_SLASH(pszBuf[cchDir - 1]), VERR_INTERNAL_ERROR_4);
+
+    /*
+     * Enumerate the directory content and dispose of it.
+     */
+    RTDIR hDir;
+    int rc = RTDirOpenFiltered(&hDir, pszBuf, RTDIRFILTER_NONE, fFlags & RTDIRRMREC_F_NO_ABS_PATH ? RTDIR_F_NO_ABS_PATH : 0);
+    if (RT_FAILURE(rc))
+        return rc;
+    while (RT_SUCCESS(rc = RTDirRead(hDir, pDirEntry, NULL)))
+    {
+        if (!RTDirEntryIsStdDotLink(pDirEntry))
+        {
+            /* Construct the full name of the entry. */
+            if (cchDir + pDirEntry->cbName + 1 /* dir slash */ >= cbBuf)
+            {
+                rc = VERR_FILENAME_TOO_LONG;
+                break;
+            }
+            memcpy(&pszBuf[cchDir], pDirEntry->szName, pDirEntry->cbName + 1);
+
+            /* Deal with the unknown type. */
+            if (pDirEntry->enmType == RTDIRENTRYTYPE_UNKNOWN)
+            {
+                rc = RTPathQueryInfoEx(pszBuf, pObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
+                if (RT_SUCCESS(rc) && RTFS_IS_DIRECTORY(pObjInfo->Attr.fMode))
+                    pDirEntry->enmType = RTDIRENTRYTYPE_DIRECTORY;
+                else if (RT_SUCCESS(rc) && RTFS_IS_FILE(pObjInfo->Attr.fMode))
+                    pDirEntry->enmType = RTDIRENTRYTYPE_FILE;
+                else if (RT_SUCCESS(rc) && RTFS_IS_SYMLINK(pObjInfo->Attr.fMode))
+                    pDirEntry->enmType = RTDIRENTRYTYPE_SYMLINK;
+            }
+
+            /* Try the delete the fs object. */
+            switch (pDirEntry->enmType)
+            {
+                case RTDIRENTRYTYPE_FILE:
+                    rc = RTFileDelete(pszBuf);
+                    break;
+
+                case RTDIRENTRYTYPE_DIRECTORY:
+                {
+                    size_t cchSubDir = cchDir + pDirEntry->cbName;
+                    pszBuf[cchSubDir++] = '/';
+                    pszBuf[cchSubDir]   = '\0';
+                    rc = rtDirRemoveRecursiveSub(pszBuf, cchSubDir, cbBuf, pDirEntry, pObjInfo, fFlags);
+                    if (RT_SUCCESS(rc))
+                    {
+                        pszBuf[cchSubDir] = '\0';
+                        rc = RTDirRemove(pszBuf);
+                    }
+                    break;
+                }
+
+                //case RTDIRENTRYTYPE_SYMLINK:
+                //    rc = RTSymlinkDelete(pszBuf, 0);
+                //    break;
+
+                default:
+                    /** @todo not implemented yet. */
+                    rc = VINF_SUCCESS;
+                    break;
+            }
+            if (RT_FAILURE(rc))
+               break;
+        }
+    }
+    if (rc == VERR_NO_MORE_FILES)
+        rc = VINF_SUCCESS;
+    RTDirClose(hDir);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRemoveRecursive(const char *pszPath, uint32_t fFlags)
+{
+    AssertReturn(!(fFlags & ~RTDIRRMREC_F_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate path buffer.
+     */
+    char  *pszAbsPath;
+    size_t cbAbsPathBuf   = RTPATH_BIG_MAX;
+    char  *pszAbsPathFree = pszAbsPath = (char *)RTMemTmpAlloc(cbAbsPathBuf);
+    if (!pszAbsPath)
+    {
+        cbAbsPathBuf = RTPATH_MAX;
+        pszAbsPath   = (char *)alloca(RTPATH_MAX);
+    }
+
+    /*
+     * Get an absolute path because this is easier to work with and
+     * eliminates any races with changing CWD.
+     */
+    int rc;
+    if (!(fFlags & RTDIRRMREC_F_NO_ABS_PATH))
+        rc = RTPathAbs(pszPath, pszAbsPath, cbAbsPathBuf);
+    else if (*pszPath != '\0')
+        rc = RTStrCopy(pszAbsPath, cbAbsPathBuf, pszPath);
+    else
+        rc = VERR_PATH_ZERO_LENGTH;
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * This API is not permitted applied to the root of anything.
+         */
+        union
+        {
+            RTPATHPARSED    Parsed;
+            uint8_t         abParsed[RTPATHPARSED_MIN_SIZE];
+        } uBuf;
+        RTPathParse(pszPath, &uBuf.Parsed, sizeof(uBuf), RTPATH_STR_F_STYLE_HOST);
+        if (   uBuf.Parsed.cComps <= 1
+            && (uBuf.Parsed.fProps & RTPATH_PROP_ROOT_SLASH))
+            rc = VERR_ACCESS_DENIED;
+        else
+        {
+            /*
+             * Because of the above restriction, we never have to deal with the root
+             * slash problem and can safely strip any trailing slashes and add a
+             * definite one.
+             */
+            RTPathStripTrailingSlash(pszAbsPath);
+            size_t cchAbsPath = strlen(pszAbsPath);
+            if (cchAbsPath + 1 < cbAbsPathBuf)
+            {
+                pszAbsPath[cchAbsPath++] = RTPATH_SLASH;
+                pszAbsPath[cchAbsPath]   = '\0';
+
+                /*
+                 * Check if it exists so we can return quietly if it doesn't.
+                 */
+                RTFSOBJINFO SharedObjInfoBuf;
+                rc = RTPathQueryInfoEx(pszAbsPath, &SharedObjInfoBuf, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
+                if (   rc == VERR_PATH_NOT_FOUND
+                    || rc == VERR_FILE_NOT_FOUND)
+                    rc = VINF_SUCCESS;
+                else if (   RT_SUCCESS(rc)
+                         && RTFS_IS_DIRECTORY(SharedObjInfoBuf.Attr.fMode))
+                {
+                    /*
+                     * We're all set for the recursion now, so get going.
+                     */
+                    RTDIRENTRY SharedDirEntryBuf;
+                    rc = rtDirRemoveRecursiveSub(pszAbsPath, cchAbsPath, cbAbsPathBuf,
+                                                 &SharedDirEntryBuf, &SharedObjInfoBuf, fFlags);
+
+                    /*
+                     * Remove the specified directory if desired and removing the content was successful.
+                     */
+                    if (   RT_SUCCESS(rc)
+                        && !(fFlags & RTDIRRMREC_F_CONTENT_ONLY))
+                    {
+                        pszAbsPath[cchAbsPath] = 0;
+                        rc = RTDirRemove(pszAbsPath);
+                    }
+                }
+                else if (RT_SUCCESS(rc))
+                    rc = VERR_NOT_A_DIRECTORY;
+
+            }
+            else
+                rc = VERR_FILENAME_TOO_LONG;
+        }
+    }
+    if (pszAbsPathFree)
+        RTMemTmpFree(pszAbsPathFree);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/fileio.cpp b/src/VBox/Runtime/r3/fileio.cpp
new file mode 100644
index 00000000..cece884a
--- /dev/null
+++ b/src/VBox/Runtime/r3/fileio.cpp
@@ -0,0 +1,423 @@
+/* $Id: fileio.cpp $ */
+/** @file
+ * IPRT - File I/O.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/alloca.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include "internal/file.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Set of forced set open flags for files opened read-only. */
+static unsigned g_fOpenReadSet = 0;
+
+/** Set of forced cleared open flags for files opened read-only. */
+static unsigned g_fOpenReadMask = 0;
+
+/** Set of forced set open flags for files opened write-only. */
+static unsigned g_fOpenWriteSet = 0;
+
+/** Set of forced cleared open flags for files opened write-only. */
+static unsigned g_fOpenWriteMask = 0;
+
+/** Set of forced set open flags for files opened read-write. */
+static unsigned g_fOpenReadWriteSet = 0;
+
+/** Set of forced cleared open flags for files opened read-write. */
+static unsigned g_fOpenReadWriteMask = 0;
+
+
+/**
+ * Force the use of open flags for all files opened after the setting is
+ * changed. The caller is responsible for not causing races with RTFileOpen().
+ *
+ * @returns iprt status code.
+ * @param   fOpenForAccess  Access mode to which the set/mask settings apply.
+ * @param   fSet            Open flags to be forced set.
+ * @param   fMask           Open flags to be masked out.
+ */
+RTR3DECL(int)  RTFileSetForceFlags(unsigned fOpenForAccess, unsigned fSet, unsigned fMask)
+{
+    /*
+     * For now allow only RTFILE_O_WRITE_THROUGH. The other flags either
+     * make no sense in this context or are not useful to apply to all files.
+     */
+    if ((fSet | fMask) & ~RTFILE_O_WRITE_THROUGH)
+        return VERR_INVALID_PARAMETER;
+    switch (fOpenForAccess)
+    {
+        case RTFILE_O_READ:
+            g_fOpenReadSet = fSet;
+            g_fOpenReadMask = fMask;
+            break;
+        case RTFILE_O_WRITE:
+            g_fOpenWriteSet = fSet;
+            g_fOpenWriteMask = fMask;
+            break;
+        case RTFILE_O_READWRITE:
+            g_fOpenReadWriteSet = fSet;
+            g_fOpenReadWriteMask = fMask;
+            break;
+        default:
+            AssertMsgFailed(("Invalid access mode %d\n", fOpenForAccess));
+            return VERR_INVALID_PARAMETER;
+    }
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Adjusts and validates the flags.
+ *
+ * The adjustments are made according to the wishes specified using the RTFileSetForceFlags API.
+ *
+ * @returns IPRT status code.
+ * @param   pfOpen      Pointer to the user specified flags on input.
+ *                      Updated on successful return.
+ * @internal
+ */
+int rtFileRecalcAndValidateFlags(uint64_t *pfOpen)
+{
+    /*
+     * Recalc.
+     */
+    uint32_t fOpen = *pfOpen;
+    switch (fOpen & RTFILE_O_ACCESS_MASK)
+    {
+        case RTFILE_O_READ:
+            fOpen |= g_fOpenReadSet;
+            fOpen &= ~g_fOpenReadMask;
+            break;
+        case RTFILE_O_WRITE:
+            fOpen |= g_fOpenWriteSet;
+            fOpen &= ~g_fOpenWriteMask;
+            break;
+        case RTFILE_O_READWRITE:
+            fOpen |= g_fOpenReadWriteSet;
+            fOpen &= ~g_fOpenReadWriteMask;
+            break;
+#ifdef RT_OS_WINDOWS
+        case RTFILE_O_ATTR_ONLY:
+            if (fOpen & RTFILE_O_ACCESS_ATTR_MASK)
+                break;
+#endif
+        default:
+            AssertMsgFailed(("Invalid access mode value, fOpen=%#llx\n", fOpen));
+            return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Validate                                                                                                                                       .
+     */
+#ifdef RT_OS_WINDOWS
+    AssertMsgReturn((fOpen & RTFILE_O_ACCESS_MASK) || (fOpen & RTFILE_O_ACCESS_ATTR_MASK),
+                    ("Missing RTFILE_O_READ/WRITE/ACCESS_ATTR: fOpen=%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+#else
+    AssertMsgReturn(fOpen & RTFILE_O_ACCESS_MASK, ("Missing RTFILE_O_READ/WRITE: fOpen=%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+#endif
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+    AssertMsgReturn(!(fOpen & (~(uint64_t)RTFILE_O_VALID_MASK | RTFILE_O_NON_BLOCK)), ("%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+#else
+    AssertMsgReturn(!(fOpen & ~(uint64_t)RTFILE_O_VALID_MASK), ("%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+#endif
+    AssertMsgReturn((fOpen & (RTFILE_O_TRUNCATE | RTFILE_O_WRITE)) != RTFILE_O_TRUNCATE, ("%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+
+    switch (fOpen & RTFILE_O_ACTION_MASK)
+    {
+        case 0: /* temporarily */
+            AssertMsgFailed(("Missing RTFILE_O_OPEN/CREATE*! (continuable assertion)\n"));
+            fOpen |= RTFILE_O_OPEN;
+            break;
+        case RTFILE_O_OPEN:
+            AssertMsgReturn(!(RTFILE_O_NOT_CONTENT_INDEXED & fOpen), ("%#llx\n", fOpen), VERR_INVALID_PARAMETER);
+        case RTFILE_O_OPEN_CREATE:
+        case RTFILE_O_CREATE:
+        case RTFILE_O_CREATE_REPLACE:
+            break;
+        default:
+            AssertMsgFailed(("Invalid action value: fOpen=%#llx\n", fOpen));
+            return VERR_INVALID_PARAMETER;
+    }
+
+    switch (fOpen & RTFILE_O_DENY_MASK)
+    {
+        case 0: /* temporarily */
+            AssertMsgFailed(("Missing RTFILE_O_DENY_*! (continuable assertion)\n"));
+            fOpen |= RTFILE_O_DENY_NONE;
+            break;
+        case RTFILE_O_DENY_NONE:
+        case RTFILE_O_DENY_READ:
+        case RTFILE_O_DENY_WRITE:
+        case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ:
+        case RTFILE_O_DENY_NOT_DELETE:
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_READ:
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_WRITE:
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ:
+            break;
+        default:
+            AssertMsgFailed(("Invalid deny value: fOpen=%#llx\n", fOpen));
+            return VERR_INVALID_PARAMETER;
+    }
+
+    /* done */
+    *pfOpen = fOpen;
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(uint64_t)  RTFileTell(RTFILE File)
+{
+    /*
+     * Call the seek api to query the stuff.
+     */
+    uint64_t off = 0;
+    int rc = RTFileSeek(File, 0, RTFILE_SEEK_CURRENT, &off);
+    if (RT_SUCCESS(rc))
+        return off;
+    AssertMsgFailed(("RTFileSeek(%d) -> %d\n", File, rc));
+    return ~0ULL;
+}
+
+
+RTR3DECL(RTFOFF) RTFileGetMaxSize(RTFILE File)
+{
+    RTFOFF cbMax;
+    int rc = RTFileQueryMaxSizeEx(File, &cbMax);
+    return RT_SUCCESS(rc) ? cbMax : -1;
+}
+
+
+RTDECL(int) RTFileCopyByHandles(RTFILE FileSrc, RTFILE FileDst)
+{
+    return RTFileCopyByHandlesEx(FileSrc, FileDst, NULL, NULL);
+}
+
+
+RTDECL(int) RTFileCompare(const char *pszFile1, const char *pszFile2)
+{
+    return RTFileCompareEx(pszFile1, pszFile2, 0 /*fFlags*/, NULL, NULL);
+}
+
+
+RTDECL(int) RTFileCompareByHandles(RTFILE hFile1, RTFILE hFile2)
+{
+    return RTFileCompareByHandlesEx(hFile1, hFile2, 0 /*fFlags*/, NULL, NULL);
+}
+
+
+RTDECL(int) RTFileCompareEx(const char *pszFile1, const char *pszFile2, uint32_t fFlags, PFNRTPROGRESS pfnProgress, void *pvUser)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszFile1, VERR_INVALID_POINTER);
+    AssertReturn(*pszFile1, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszFile2, VERR_INVALID_POINTER);
+    AssertReturn(*pszFile2, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pfnProgress, VERR_INVALID_POINTER);
+    AssertMsgReturn(!(fFlags & ~RTFILECOMP_FLAGS_MASK), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Open the files.
+     */
+    RTFILE hFile1;
+    int rc = RTFileOpen(&hFile1, pszFile1,
+                        RTFILE_O_READ | RTFILE_O_OPEN
+                        | (fFlags & RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE1 ? RTFILE_O_DENY_NONE : RTFILE_O_DENY_WRITE));
+    if (RT_SUCCESS(rc))
+    {
+        RTFILE hFile2;
+        rc = RTFileOpen(&hFile2, pszFile2,
+                        RTFILE_O_READ | RTFILE_O_OPEN
+                        | (fFlags & RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE2 ? RTFILE_O_DENY_NONE : RTFILE_O_DENY_WRITE));
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Call the ByHandles version and let it do the job.
+             */
+            rc = RTFileCompareByHandlesEx(hFile1, hFile2, fFlags,  pfnProgress, pvUser);
+
+            /* Clean up */
+            int rc2 = RTFileClose(hFile2);
+            AssertRC(rc2);
+            if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
+                rc = rc2;
+        }
+
+        int rc2 = RTFileClose(hFile1);
+        AssertRC(rc2);
+        if (RT_FAILURE(rc2) && RT_SUCCESS(rc))
+            rc = rc2;
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTFileCompareByHandlesEx(RTFILE hFile1, RTFILE hFile2, uint32_t fFlags, PFNRTPROGRESS pfnProgress, void *pvUser)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(RTFileIsValid(hFile1), VERR_INVALID_HANDLE);
+    AssertReturn(RTFileIsValid(hFile1), VERR_INVALID_HANDLE);
+    AssertPtrNullReturn(pfnProgress, VERR_INVALID_POINTER);
+    AssertMsgReturn(!(fFlags & ~RTFILECOMP_FLAGS_MASK), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Compare the file sizes first.
+     */
+    uint64_t cbFile1;
+    int rc = RTFileQuerySize(hFile1, &cbFile1);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    uint64_t cbFile2;
+    rc = RTFileQuerySize(hFile1, &cbFile2);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    if (cbFile1 != cbFile2)
+        return VERR_NOT_EQUAL;
+
+
+    /*
+     * Allocate buffer.
+     */
+    size_t      cbBuf;
+    uint8_t    *pbBuf1Free = NULL;
+    uint8_t    *pbBuf1;
+    uint8_t    *pbBuf2Free = NULL;
+    uint8_t    *pbBuf2;
+    if (cbFile1 < _512K)
+    {
+        cbBuf  = 8*_1K;
+        pbBuf1 = (uint8_t *)alloca(cbBuf);
+        pbBuf2 = (uint8_t *)alloca(cbBuf);
+    }
+    else
+    {
+        cbBuf = _128K;
+        pbBuf1 = pbBuf1Free = (uint8_t *)RTMemTmpAlloc(cbBuf);
+        pbBuf2 = pbBuf2Free = (uint8_t *)RTMemTmpAlloc(cbBuf);
+    }
+    if (pbBuf1 && pbBuf2)
+    {
+        /*
+         * Seek to the start of each file
+         * and set the size of the destination file.
+         */
+        rc = RTFileSeek(hFile1, 0, RTFILE_SEEK_BEGIN, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTFileSeek(hFile2, 0, RTFILE_SEEK_BEGIN, NULL);
+            if (RT_SUCCESS(rc) && pfnProgress)
+                rc = pfnProgress(0, pvUser);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Compare loop.
+                 */
+                unsigned    uPercentage    = 0;
+                RTFOFF      off            = 0;
+                RTFOFF      cbPercent      = cbFile1 / 100;
+                RTFOFF      offNextPercent = cbPercent;
+                while (off < (RTFOFF)cbFile1)
+                {
+                    /* read the blocks */
+                    RTFOFF cbLeft = cbFile1 - off;
+                    size_t cbBlock = cbLeft >= (RTFOFF)cbBuf ? cbBuf : (size_t)cbLeft;
+                    rc = RTFileRead(hFile1, pbBuf1, cbBlock, NULL);
+                    if (RT_FAILURE(rc))
+                        break;
+                    rc = RTFileRead(hFile2, pbBuf2, cbBlock, NULL);
+                    if (RT_FAILURE(rc))
+                        break;
+
+                    /* compare */
+                    if (memcmp(pbBuf1, pbBuf2, cbBlock))
+                    {
+                        rc = VERR_NOT_EQUAL;
+                        break;
+                    }
+
+                    /* advance */
+                    off += cbBlock;
+                    if (pfnProgress && offNextPercent < off)
+                    {
+                        while (offNextPercent < off)
+                        {
+                            uPercentage++;
+                            offNextPercent += cbPercent;
+                        }
+                        rc = pfnProgress(uPercentage, pvUser);
+                        if (RT_FAILURE(rc))
+                            break;
+                    }
+                }
+
+#if 0
+                /*
+                 * Compare OS specific data (EAs and stuff).
+                 */
+                if (RT_SUCCESS(rc))
+                    rc = rtFileCompareOSStuff(hFile1, hFile2);
+#endif
+
+                /* 100% */
+                if (pfnProgress && uPercentage < 100 && RT_SUCCESS(rc))
+                    rc = pfnProgress(100, pvUser);
+            }
+        }
+    }
+    else
+        rc = VERR_NO_MEMORY;
+    RTMemTmpFree(pbBuf2Free);
+    RTMemTmpFree(pbBuf1Free);
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/freebsd/Makefile.kup b/src/VBox/Runtime/r3/freebsd/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/Makefile.kup
diff --git a/src/VBox/Runtime/r3/freebsd/RTFileQuerySectorSize-freebsd.cpp b/src/VBox/Runtime/r3/freebsd/RTFileQuerySectorSize-freebsd.cpp
new file mode 100644
index 00000000..15075d63
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/RTFileQuerySectorSize-freebsd.cpp
@@ -0,0 +1,88 @@
+/* $Id: RTFileQuerySectorSize-freebsd.cpp $ */
+/** @file
+ * IPRT - RTFileQuerySectorSize, FreeBSD.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <errno.h>
+#include <sys/disk.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+
+
+
+RTDECL(int) RTFileQuerySectorSize(RTFILE hFile, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pcbSector, VERR_INVALID_PARAMETER);
+
+    int rc;
+    int const fd = (int)RTFileToNative(hFile);
+    struct stat DevStat = { 0 };
+    if (!fstat(fd, &DevStat))
+    {
+        if (S_ISCHR(DevStat.st_mode))
+        {
+            u_int cbSector = 0;
+            if (!ioctl(fd, DIOCGSECTORSIZE, &cbSector))
+            {
+                AssertReturn(cbSector > 0, VERR_INVALID_FUNCTION);
+                *pcbSector = cbSector;
+                return VINF_SUCCESS;
+            }
+            rc = RTErrConvertFromErrno(errno);
+            AssertMsgFailed(("ioctl failed: errno=%d / %Rrc\n", errno, rc));
+        }
+        else
+        {
+            AssertMsgFailed(("not a character device.\n"));
+            rc = VERR_INVALID_FUNCTION;
+        }
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(errno);
+        AssertMsgFailed(("fstat failed: errno=%d / %Rrc\n", errno, rc));
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/freebsd/fileaio-freebsd.cpp b/src/VBox/Runtime/r3/freebsd/fileaio-freebsd.cpp
new file mode 100644
index 00000000..46190a5f
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/fileaio-freebsd.cpp
@@ -0,0 +1,682 @@
+/* $Id: fileaio-freebsd.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for the FreeBSD host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/asm.h>
+#include <iprt/file.h>
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/thread.h>
+#include "internal/fileaio.h"
+
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include <sys/sysctl.h>
+#include <aio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** Handle to the kernel queue. */
+    int               iKQueue;
+    /** Current number of requests active on this context. */
+    volatile int32_t  cRequests;
+    /** The ID of the thread which is currently waiting for requests. */
+    volatile RTTHREAD hThreadWait;
+    /** Flag whether the thread was woken up. */
+    volatile bool     fWokenUp;
+    /** Flag whether the thread is currently waiting in the syscall. */
+    volatile bool     fWaiting;
+    /** Flags given during creation. */
+    uint32_t          fFlags;
+    /** Magic value (RTFILEAIOCTX_MAGIC). */
+    uint32_t          u32Magic;
+} RTFILEAIOCTXINTERNAL;
+/** Pointer to an internal context structure. */
+typedef RTFILEAIOCTXINTERNAL *PRTFILEAIOCTXINTERNAL;
+
+/**
+ * Async I/O request state.
+ */
+typedef struct RTFILEAIOREQINTERNAL
+{
+    /** The aio control block. Must be the FIRST
+     *  element. */
+    struct aiocb           AioCB;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE      enmState;
+    /** Flag whether this is a flush request. */
+    bool                   fFlush;
+    /** Opaque user data. */
+    void                  *pvUser;
+    /** Completion context we are assigned to. */
+    PRTFILEAIOCTXINTERNAL  pCtxInt;
+    /** Number of bytes actually transferred. */
+    size_t                 cbTransfered;
+    /** Status code. */
+    int                    Rc;
+    /** Magic value  (RTFILEAIOREQ_MAGIC). */
+    uint32_t               u32Magic;
+} RTFILEAIOREQINTERNAL;
+/** Pointer to an internal request structure. */
+typedef RTFILEAIOREQINTERNAL *PRTFILEAIOREQINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The max number of events to get in one call. */
+#define AIO_MAXIMUM_REQUESTS_PER_CONTEXT 64
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    int rcBSD = 0;
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+    /*
+     * The AIO API is implemented in a kernel module which is not
+     * loaded by default.
+     * If it is loaded there are additional sysctl parameters.
+     */
+    int cReqsOutstandingMax = 0;
+    size_t cbParameter = sizeof(int);
+
+    rcBSD = sysctlbyname("vfs.aio.max_aio_per_proc", /* name */
+                         &cReqsOutstandingMax,       /* Where to store the old value. */
+                         &cbParameter,               /* Size of the memory pointed to. */
+                         NULL,                       /* Where the new value is located. */
+                         0);                         /* Where the size of the new value is stored. */
+    if (rcBSD == -1)
+    {
+        /* ENOENT means the value is unknown thus the module is not loaded. */
+        if (errno == ENOENT)
+            return VERR_NOT_SUPPORTED;
+        else
+            return RTErrConvertFromErrno(errno);
+    }
+
+    pAioLimits->cReqsOutstandingMax = cReqsOutstandingMax;
+    pAioLimits->cbBufferAlignment   = 0;
+
+    return VINF_SUCCESS;
+}
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOREQINTERNAL));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    /* Ininitialize static parts. */
+    pReqInt->AioCB.aio_sigevent.sigev_notify = SIGEV_KEVENT;
+    pReqInt->AioCB.aio_sigevent.sigev_value.sival_ptr = pReqInt;
+    pReqInt->pCtxInt                   = NULL;
+    pReqInt->u32Magic                  = RTFILEAIOREQ_MAGIC;
+    RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+    *phReq = (RTFILEAIOREQ)pReqInt;
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
+{
+    /*
+     * Validate the handle and ignore nil.
+     */
+    if (hReq == NIL_RTFILEAIOREQ)
+        return VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    /*
+     * Trash the magic and free it.
+     */
+    ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
+    RTMemFree(pReqInt);
+    return VINF_SUCCESS;
+}
+
+/**
+ * Worker setting up the request.
+ */
+DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
+                                            unsigned uTransferDirection,
+                                            RTFOFF off, void *pvBuf, size_t cbTransfer,
+                                            void *pvUser)
+{
+    /*
+     * Validate the input.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+    AssertPtr(pvBuf);
+    Assert(off >= 0);
+    Assert(cbTransfer > 0);
+
+    pReqInt->AioCB.aio_sigevent.sigev_notify = SIGEV_KEVENT;
+    pReqInt->AioCB.aio_sigevent.sigev_value.sival_ptr = pReqInt;
+    pReqInt->AioCB.aio_lio_opcode = uTransferDirection;
+    pReqInt->AioCB.aio_fildes     = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset     = off;
+    pReqInt->AioCB.aio_nbytes     = cbTransfer;
+    pReqInt->AioCB.aio_buf        = pvBuf;
+    pReqInt->fFlush               = false;
+    pReqInt->pvUser               = pvUser;
+    pReqInt->pCtxInt              = NULL;
+    pReqInt->Rc                   = VERR_FILE_AIO_IN_PROGRESS;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                    void *pvBuf, size_t cbRead, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_READ,
+                                       off, pvBuf, cbRead, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                     void const *pvBuf, size_t cbWrite, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)hReq;
+
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    Assert(hFile != NIL_RTFILE);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    pReqInt->fFlush           = true;
+    pReqInt->AioCB.aio_fildes = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset = 0;
+    pReqInt->AioCB.aio_nbytes = 0;
+    pReqInt->AioCB.aio_buf    = NULL;
+    pReqInt->pvUser           = pvUser;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->pvUser;
+}
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+
+    int rcBSD = aio_cancel(pReqInt->AioCB.aio_fildes, &pReqInt->AioCB);
+
+    if (rcBSD == AIO_CANCELED)
+    {
+        /*
+         * Decrement request count because the request will never arrive at the
+         * completion port.
+         */
+        AssertMsg(RT_VALID_PTR(pReqInt->pCtxInt),
+                  ("Invalid state. Request was canceled but wasn't submitted\n"));
+
+        ASMAtomicDecS32(&pReqInt->pCtxInt->cRequests);
+        pReqInt->Rc = VERR_FILE_AIO_CANCELED;
+        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+        return VINF_SUCCESS;
+    }
+    else if (rcBSD == AIO_ALLDONE)
+        return VERR_FILE_AIO_COMPLETED;
+    else if (rcBSD == AIO_NOTCANCELED)
+        return VERR_FILE_AIO_IN_PROGRESS;
+    else
+        return RTErrConvertFromErrno(errno);
+}
+
+RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    AssertPtrNull(pcbTransfered);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    if (  (RT_SUCCESS(pReqInt->Rc))
+        && (pcbTransfered))
+        *pcbTransfered = pReqInt->cbTransfered;
+
+    return pReqInt->Rc;
+}
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
+                               uint32_t fFlags)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
+    if (RT_UNLIKELY(!pCtxInt))
+        return VERR_NO_MEMORY;
+
+    /* Init the event handle. */
+    pCtxInt->iKQueue = kqueue();
+    if (RT_LIKELY(pCtxInt->iKQueue > 0))
+    {
+        pCtxInt->fFlags       = fFlags;
+        pCtxInt->u32Magic     = RTFILEAIOCTX_MAGIC;
+        *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+    }
+    else
+    {
+        RTMemFree(pCtxInt);
+        rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
+{
+    /* Validate the handle and ignore nil. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /* Cannot destroy a busy context. */
+    if (RT_UNLIKELY(pCtxInt->cRequests))
+        return VERR_FILE_AIO_BUSY;
+
+    close(pCtxInt->iKQueue);
+    ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    return RTFILEAIO_UNLIMITED_REQS;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    /*
+     * Parameter validation.
+     */
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertReturn(cReqs > 0,  VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+
+    do
+    {
+        int rcBSD = 0;
+        size_t cReqsSubmit = 0;
+        size_t i = 0;
+        PRTFILEAIOREQINTERNAL pReqInt;
+
+        while (   (i < cReqs)
+               && (i < AIO_LISTIO_MAX))
+        {
+            pReqInt = pahReqs[i];
+            if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
+            {
+                /* Undo everything and stop submitting. */
+                for (size_t iUndo = 0; iUndo < i; iUndo++)
+                {
+                    pReqInt = pahReqs[iUndo];
+                    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                    pReqInt->pCtxInt = NULL;
+                    pReqInt->AioCB.aio_sigevent.sigev_notify_kqueue = 0;
+                }
+                rc = VERR_INVALID_HANDLE;
+                break;
+            }
+
+            pReqInt->AioCB.aio_sigevent.sigev_notify_kqueue = pCtxInt->iKQueue;
+            pReqInt->pCtxInt                                = pCtxInt;
+            RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+
+            if (pReqInt->fFlush)
+                break;
+
+            cReqsSubmit++;
+            i++;
+        }
+
+        if (cReqsSubmit)
+        {
+            rcBSD = lio_listio(LIO_NOWAIT, (struct aiocb **)pahReqs, cReqsSubmit, NULL);
+            if (RT_UNLIKELY(rcBSD < 0))
+            {
+                if (errno == EAGAIN)
+                    rc = VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+
+                /* Check which requests got actually submitted and which not. */
+                for (i = 0; i < cReqs; i++)
+                {
+                    pReqInt = pahReqs[i];
+                    rcBSD = aio_error(&pReqInt->AioCB);
+                    if (   rcBSD == -1
+                        && errno == EINVAL)
+                    {
+                        /* Was not submitted. */
+                        RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                        pReqInt->pCtxInt = NULL;
+                    }
+                    else if (rcBSD != EINPROGRESS)
+                    {
+                        /* The request encountered an error. */
+                        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                        pReqInt->Rc = RTErrConvertFromErrno(rcBSD);
+                        pReqInt->pCtxInt      = NULL;
+                        pReqInt->cbTransfered = 0;
+                    }
+                }
+                break;
+            }
+
+            ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmit);
+            cReqs   -= cReqsSubmit;
+            pahReqs += cReqsSubmit;
+        }
+
+        /* Check if we have a flush request now. */
+        if (cReqs && RT_SUCCESS_NP(rc))
+        {
+            pReqInt = pahReqs[0];
+            RTFILEAIOREQ_VALID_RETURN(pReqInt);
+
+            if (pReqInt->fFlush)
+            {
+                /*
+                 * lio_listio does not work with flush requests so
+                 * we have to use aio_fsync directly.
+                 */
+                 rcBSD = aio_fsync(O_SYNC, &pReqInt->AioCB);
+                 if (RT_UNLIKELY(rcBSD < 0))
+                 {
+                    if (rcBSD == EAGAIN)
+                    {
+                        /* Was not submitted. */
+                        RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                        pReqInt->pCtxInt = NULL;
+                        return VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+                    }
+                    else
+                    {
+                        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                        pReqInt->Rc = RTErrConvertFromErrno(errno);
+                        pReqInt->cbTransfered = 0;
+                        return pReqInt->Rc;
+                    }
+                 }
+
+                ASMAtomicIncS32(&pCtxInt->cRequests);
+                cReqs--;
+                pahReqs++;
+            }
+        }
+    } while (cReqs);
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+
+    /*
+     * Validate the parameters, making sure to always set pcReqs.
+     */
+    AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
+    *pcReqs = 0; /* always set */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
+    AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
+
+    if (   RT_UNLIKELY(ASMAtomicReadS32(&pCtxInt->cRequests) == 0)
+        && !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
+        return VERR_FILE_AIO_NO_REQUEST;
+
+    /*
+     * Convert the timeout if specified.
+     */
+    struct timespec    *pTimeout = NULL;
+    struct timespec     Timeout = {0,0};
+    uint64_t            StartNanoTS = 0;
+    if (cMillies != RT_INDEFINITE_WAIT)
+    {
+        Timeout.tv_sec  = cMillies / 1000;
+        Timeout.tv_nsec = cMillies % 1000 * 1000000;
+        pTimeout = &Timeout;
+        StartNanoTS = RTTimeNanoTS();
+    }
+
+    /* Wait for at least one. */
+    if (!cMinReqs)
+        cMinReqs = 1;
+
+    /* For the wakeup call. */
+    Assert(pCtxInt->hThreadWait == NIL_RTTHREAD);
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, RTThreadSelf());
+
+    while (   cMinReqs
+           && RT_SUCCESS_NP(rc))
+    {
+        struct kevent aKEvents[AIO_MAXIMUM_REQUESTS_PER_CONTEXT];
+        int cRequestsToWait = cMinReqs < AIO_MAXIMUM_REQUESTS_PER_CONTEXT ? cReqs : AIO_MAXIMUM_REQUESTS_PER_CONTEXT;
+        int rcBSD;
+        uint64_t StartTime;
+
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
+        rcBSD = kevent(pCtxInt->iKQueue, NULL, 0, aKEvents, cRequestsToWait, pTimeout);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
+
+        if (RT_UNLIKELY(rcBSD < 0))
+        {
+            rc = RTErrConvertFromErrno(errno);
+            break;
+        }
+
+        uint32_t const cDone = rcBSD;
+
+        /* Process received events. */
+        for (uint32_t i = 0; i < cDone; i++)
+        {
+            PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)aKEvents[i].udata;
+            AssertPtr(pReqInt);
+            Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
+
+            /*
+             * Retrieve the status code here already because the
+             * user may omit the RTFileAioReqGetRC() call and
+             * we will leak kernel resources then.
+             * This will result in errors during submission
+             * of other requests as soon as the max_aio_queue_per_proc
+             * limit is reached.
+             */
+            int cbTransfered = aio_return(&pReqInt->AioCB);
+
+            if (cbTransfered < 0)
+            {
+                pReqInt->Rc = RTErrConvertFromErrno(cbTransfered);
+                pReqInt->cbTransfered = 0;
+            }
+            else
+            {
+                pReqInt->Rc = VINF_SUCCESS;
+                pReqInt->cbTransfered = cbTransfered;
+            }
+            RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+            pahReqs[cRequestsCompleted++] = (RTFILEAIOREQ)pReqInt;
+        }
+
+        /*
+         * Done Yet? If not advance and try again.
+         */
+        if (cDone >= cMinReqs)
+            break;
+        cMinReqs -= cDone;
+        cReqs    -= cDone;
+
+        if (cMillies != RT_INDEFINITE_WAIT)
+        {
+            /* The API doesn't return ETIMEDOUT, so we have to fix that ourselves. */
+            uint64_t NanoTS = RTTimeNanoTS();
+            uint64_t cMilliesElapsed = (NanoTS - StartNanoTS) / 1000000;
+            if (cMilliesElapsed >= cMillies)
+            {
+                rc = VERR_TIMEOUT;
+                break;
+            }
+
+            /* The syscall supposedly updates it, but we're paranoid. :-) */
+            Timeout.tv_sec  = (cMillies - (RTMSINTERVAL)cMilliesElapsed) / 1000;
+            Timeout.tv_nsec = (cMillies - (RTMSINTERVAL)cMilliesElapsed) % 1000 * 1000000;
+        }
+    }
+
+    /*
+     * Update the context state and set the return value.
+     */
+    *pcReqs = cRequestsCompleted;
+    ASMAtomicSubS32(&pCtxInt->cRequests, cRequestsCompleted);
+    Assert(pCtxInt->hThreadWait == RTThreadSelf());
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, NIL_RTTHREAD);
+
+    /*
+     * Clear the wakeup flag and set rc.
+     */
+    if (    pCtxInt->fWokenUp
+        &&  RT_SUCCESS(rc))
+    {
+        ASMAtomicXchgBool(&pCtxInt->fWokenUp, false);
+        rc = VERR_INTERRUPTED;
+    }
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /** @todo r=bird: Define the protocol for how to resume work after calling
+     *        this function. */
+
+    bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUp, true);
+
+    /*
+     * Read the thread handle before the status flag.
+     * If we read the handle after the flag we might
+     * end up with an invalid handle because the thread
+     * waiting in RTFileAioCtxWakeup() might get scheduled
+     * before we read the flag and returns.
+     * We can ensure that the handle is valid if fWaiting is true
+     * when reading the handle before the status flag.
+     */
+    RTTHREAD hThread;
+    ASMAtomicReadHandle(&pCtxInt->hThreadWait, &hThread);
+    bool fWaiting    = ASMAtomicReadBool(&pCtxInt->fWaiting);
+    if (    !fWokenUp
+        &&  fWaiting)
+    {
+        /*
+         * If a thread waits the handle must be valid.
+         * It is possible that the thread returns from
+         * kevent() before the signal is send.
+         * This is no problem because we already set fWokenUp
+         * to true which will let the thread return VERR_INTERRUPTED
+         * and the next call to RTFileAioCtxWait() will not
+         * return VERR_INTERRUPTED because signals are not saved
+         * and will simply vanish if the destination thread can't
+         * receive it.
+         */
+        Assert(hThread != NIL_RTTHREAD);
+        RTThreadPoke(hThread);
+    }
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/freebsd/mp-freebsd.cpp b/src/VBox/Runtime/r3/freebsd/mp-freebsd.cpp
new file mode 100644
index 00000000..8b2f5f83
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/mp-freebsd.cpp
@@ -0,0 +1,211 @@
+/* $Id: mp-freebsd.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, FreeBSD.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <sys/sysctl.h>
+
+#include <iprt/mp.h>
+#include <iprt/cpuset.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/alloc.h>
+#include <iprt/log.h>
+#include <iprt/once.h>
+#include <iprt/critsect.h>
+
+
+/**
+ * Internal worker that determines the max possible CPU count.
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpFreeBsdMaxCpus(void)
+{
+    int aiMib[2];
+    aiMib[0] = CTL_HW;
+    aiMib[1] = HW_NCPU;
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctl(aiMib, RT_ELEMENTS(aiMib), &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+    AssertFailed();
+    return 1;
+}
+
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    return idCpu < RTCPUSET_MAX_CPUS && idCpu < rtMpFreeBsdMaxCpus() ? idCpu : -1;
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    return (unsigned)iCpu < rtMpFreeBsdMaxCpus() ? iCpu : NIL_RTCPUID;
+}
+
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    return rtMpFreeBsdMaxCpus() - 1;
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+    /*
+     * FreeBSD doesn't support CPU hotplugging so every CPU which appears
+     * in the tree is also online.
+     */
+    char    szName[40];
+    RTStrPrintf(szName, sizeof(szName), "dev.cpu.%d.%%driver", (int)idCpu);
+
+    char    szDriver[10];
+    size_t  cbDriver = sizeof(szDriver);
+    RT_ZERO(szDriver);                  /* this shouldn't be necessary. */
+    int rcBsd = sysctlbyname(szName, szDriver, &cbDriver, NULL, 0);
+    if (rcBsd == 0)
+        return true;
+
+    return false;
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    return idCpu != NIL_RTCPUID
+        && idCpu < rtMpFreeBsdMaxCpus();
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    RTCPUID cMax = rtMpFreeBsdMaxCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuPossible(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    return rtMpFreeBsdMaxCpus();
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    RTCPUID cMax = rtMpFreeBsdMaxCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuOnline(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+    /*
+     * FreeBSD has sysconf.
+     */
+    return sysconf(_SC_NPROCESSORS_ONLN);
+}
+
+
+RTDECL(uint32_t) RTMpGetCurFrequency(RTCPUID idCpu)
+{
+    int uFreqCurr = 0;
+    size_t cbParameter = sizeof(uFreqCurr);
+
+    if (!RTMpIsCpuOnline(idCpu))
+        return 0;
+
+    /* CPU's have a common frequency. */
+    int rc = sysctlbyname("dev.cpu.0.freq", &uFreqCurr, &cbParameter, NULL, 0);
+    if (rc)
+        return 0;
+
+    return (uint32_t)uFreqCurr;
+}
+
+
+RTDECL(uint32_t) RTMpGetMaxFrequency(RTCPUID idCpu)
+{
+    char szFreqLevels[20]; /* Should be enough to get the highest level which is always the first. */
+    size_t cbFreqLevels = sizeof(szFreqLevels);
+
+    if (!RTMpIsCpuOnline(idCpu))
+        return 0;
+
+    memset(szFreqLevels, 0, sizeof(szFreqLevels));
+
+    /*
+     * CPU 0 has the freq levels entry. ENOMEM is ok as we don't need all supported
+     * levels but only the first one.
+     */
+    int rc = sysctlbyname("dev.cpu.0.freq_levels", szFreqLevels, &cbFreqLevels, NULL, 0);
+    if (   (rc && (errno != ENOMEM))
+        || (cbFreqLevels == 0))
+        return 0;
+
+    /* Clear everything starting from the '/' */
+    unsigned i = 0;
+
+    do
+    {
+        if (szFreqLevels[i] == '/')
+        {
+            memset(&szFreqLevels[i], 0, sizeof(szFreqLevels) - i);
+            break;
+        }
+        i++;
+    } while (i < sizeof(szFreqLevels));
+
+    /* Returns 0 on failure. */
+    return RTStrToUInt32(szFreqLevels);
+}
+
diff --git a/src/VBox/Runtime/r3/freebsd/rtProcInitExePath-freebsd.cpp b/src/VBox/Runtime/r3/freebsd/rtProcInitExePath-freebsd.cpp
new file mode 100644
index 00000000..5994f994
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/rtProcInitExePath-freebsd.cpp
@@ -0,0 +1,139 @@
+/* $Id: rtProcInitExePath-freebsd.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, FreeBSD.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <dlfcn.h>
+#include <link.h>
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+#ifdef KERN_PROC_PATHNAME
+    int aiName[4];
+    aiName[0] = CTL_KERN;
+    aiName[1] = KERN_PROC;
+    aiName[2] = KERN_PROC_PATHNAME;     /* This was introduced in FreeBSD 6.0, thus the #ifdef above. */
+    aiName[3] = -1;                     /* Shorthand for the current process. */
+
+    size_t cchExePath = cchPath;
+    if (sysctl(aiName, RT_ELEMENTS(aiName), pszPath, &cchExePath, NULL, 0) == 0)
+    {
+        const char *pszTmp;
+        int rc = rtPathFromNative(&pszTmp, pszPath, NULL);
+        AssertMsgRCReturn(rc, ("rc=%Rrc pszPath=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchExePath, pszPath), rc);
+        if (pszTmp != pszPath)
+        {
+            rc = RTStrCopy(pszPath, cchPath, pszTmp);
+            rtPathFreeIprt(pszTmp, pszPath);
+        }
+        return rc;
+    }
+
+    int rc = RTErrConvertFromErrno(errno);
+    AssertMsgFailed(("rc=%Rrc errno=%d cchExePath=%d\n", rc, errno, cchExePath));
+    return rc;
+
+#else
+
+    /*
+     * Read the /proc/curproc/file link, convert to native and return it.
+     */
+    int cchLink = readlink("/proc/curproc/file", pszPath, cchPath - 1);
+    if (cchLink > 0 && (size_t)cchLink <= cchPath - 1)
+    {
+        pszPath[cchLink] = '\0';
+
+        char const *pszTmp;
+        int rc = rtPathFromNative(&pszTmp, pszPath);
+        AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchLink, pszPath), rc);
+        if (pszTmp != pszPath)
+        {
+            rc = RTStrCopy(pszPath, cchPath, pszTmp);
+            rtPathFreeIprt(pszTmp);
+        }
+        return rc;
+    }
+
+    int err = errno;
+
+    /*
+     * Fall back on the dynamic linker since /proc is optional.
+     */
+    void *hExe = dlopen(NULL, 0);
+    if (hExe)
+    {
+        struct link_map const *pLinkMap = 0;
+        if (dlinfo(hExe, RTLD_DI_LINKMAP, &pLinkMap) == 0)
+        {
+            const char *pszImageName = pLinkMap->l_name;
+            if (*pszImageName == '/') /* this may not always be absolute, despite the docs. :-( */
+            {
+                char const *pszTmp;
+                int rc = rtPathFromNative(&pszTmp, pszImageName, NULL);
+                AssertMsgRCReturn(rc, ("rc=%Rrc pszImageName=\"%s\"\n", rc, pszImageName), rc);
+                if (pszTmp != pszPath)
+                {
+                    rc = RTStrCopy(pszPath, cchPath, pszTmp);
+                    rtPathFreeIprt(pszTmp, pszPath);
+                }
+                return rc;
+            }
+            /** @todo Try search the PATH for the file name or append the current
+             *        directory, which ever makes sense... */
+        }
+    }
+
+    int rc = RTErrConvertFromErrno(err);
+    AssertMsgFailed(("rc=%Rrc err=%d cchLink=%d hExe=%p\n", rc, err, cchLink, hExe));
+    return rc;
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/freebsd/systemmem-freebsd.cpp b/src/VBox/Runtime/r3/freebsd/systemmem-freebsd.cpp
new file mode 100644
index 00000000..b662fc67
--- /dev/null
+++ b/src/VBox/Runtime/r3/freebsd/systemmem-freebsd.cpp
@@ -0,0 +1,108 @@
+/* $Id: systemmem-freebsd.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, Linux ring-3.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <errno.h>
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    int rc = VINF_SUCCESS;
+    u_long cbMemPhys = 0;
+    size_t cbParameter = sizeof(cbMemPhys);
+
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    if (!sysctlbyname("hw.physmem", &cbMemPhys, &cbParameter, NULL, 0))
+    {
+        *pcb = cbMemPhys;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    u_int cPagesMemFree = 0;
+    u_int cPagesMemInactive = 0;
+    u_int cPagesMemCached = 0;
+    u_int cPagesMemUsed = 0;
+    int cbPage = 0;
+    size_t cbParameter;
+    int cProcessed = 0;
+
+    cbParameter = sizeof(cPagesMemFree);
+    if (sysctlbyname("vm.stats.vm.v_free_count", &cPagesMemFree, &cbParameter, NULL, 0))
+        rc = RTErrConvertFromErrno(errno);
+    cbParameter = sizeof(cPagesMemUsed);
+    if (   RT_SUCCESS(rc)
+        && sysctlbyname("vm.stats.vm.v_active_count", &cPagesMemUsed, &cbParameter, NULL, 0))
+        rc = RTErrConvertFromErrno(errno);
+    cbParameter = sizeof(cPagesMemInactive);
+    if (   RT_SUCCESS(rc)
+        && sysctlbyname("vm.stats.vm.v_inactive_count", &cPagesMemInactive, &cbParameter, NULL, 0))
+        rc = RTErrConvertFromErrno(errno);
+    cbParameter = sizeof(cPagesMemCached);
+    if (   RT_SUCCESS(rc)
+        && sysctlbyname("vm.stats.vm.v_cache_count", &cPagesMemCached, &cbParameter, NULL, 0))
+        rc = RTErrConvertFromErrno(errno);
+    cbParameter = sizeof(cbPage);
+    if (   RT_SUCCESS(rc)
+        && sysctlbyname("hw.pagesize", &cbPage, &cbParameter, NULL, 0))
+        rc = RTErrConvertFromErrno(errno);
+
+    if (RT_SUCCESS(rc))
+        *pcb = (cPagesMemFree + cPagesMemInactive + cPagesMemCached ) * cbPage;
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/fs.cpp b/src/VBox/Runtime/r3/fs.cpp
new file mode 100644
index 00000000..41f7de8d
--- /dev/null
+++ b/src/VBox/Runtime/r3/fs.cpp
@@ -0,0 +1,274 @@
+/* $Id: fs.cpp $ */
+/** @file
+ * IPRT - File System.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/fs.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include "internal/fs.h"
+
+
+/**
+ * Converts dos-style attributes to Unix attributes.
+ *
+ * @returns Normalized mode mask.
+ * @param   fMode       The mode mask containing dos-style attributes only.
+ * @param   pszName     The filename which this applies to (exe check).
+ * @param   cbName      The length of that filename. (optional, set 0)
+ * @param   uReparseTag The reparse tag if RTFS_DOS_NT_REPARSE_POINT is set.
+ * @param   fType       RTFS_TYPE_XXX to normalize against, 0 if not known.
+ */
+RTFMODE rtFsModeFromDos(RTFMODE fMode, const char *pszName, size_t cbName, uint32_t uReparseTag, RTFMODE fType)
+{
+    Assert(!(fType & ~RTFS_TYPE_MASK));
+
+    fMode &= ~((1 << RTFS_DOS_SHIFT) - 1);
+
+    /* Forcibly set the directory attribute if caller desires it. */
+    if (fType == RTFS_TYPE_DIRECTORY)
+        fMode |= RTFS_DOS_DIRECTORY;
+
+    /* Everything is readable. */
+    fMode |= RTFS_UNIX_IRUSR | RTFS_UNIX_IRGRP | RTFS_UNIX_IROTH;
+    if (fMode & RTFS_DOS_DIRECTORY)
+        /* Directories are executable. */
+        fMode |= RTFS_TYPE_DIRECTORY | RTFS_UNIX_IXUSR | RTFS_UNIX_IXGRP | RTFS_UNIX_IXOTH;
+    else
+    {
+        fMode |= RTFS_TYPE_FILE;
+        if (!cbName && pszName)
+            cbName = strlen(pszName);
+        if (cbName >= 4 && pszName[cbName - 4] == '.')
+        {
+            /* check for executable extension. */
+            const char *pszExt = &pszName[cbName - 3];
+            char szExt[4];
+            szExt[0] = RT_C_TO_LOWER(pszExt[0]);
+            szExt[1] = RT_C_TO_LOWER(pszExt[1]);
+            szExt[2] = RT_C_TO_LOWER(pszExt[2]);
+            szExt[3] = '\0';
+            if (    !memcmp(szExt, "exe", 4)
+                ||  !memcmp(szExt, "bat", 4)
+                ||  !memcmp(szExt, "com", 4)
+                ||  !memcmp(szExt, "cmd", 4)
+                ||  !memcmp(szExt, "btm", 4)
+               )
+                fMode |= RTFS_UNIX_IXUSR | RTFS_UNIX_IXGRP | RTFS_UNIX_IXOTH;
+        }
+    }
+
+    /* Is it really a symbolic link? */
+    if ((fMode & RTFS_DOS_NT_REPARSE_POINT) && uReparseTag == RTFSMODE_SYMLINK_REPARSE_TAG)
+        fMode = (fMode & ~RTFS_TYPE_MASK) | RTFS_TYPE_SYMLINK;
+
+    /*
+     * Writable?
+     *
+     * Note! We ignore the read-only flag on directories as windows seems to
+     *       use it for purposes other than writability (@ticketref{18345}):
+     *       https://support.microsoft.com/en-gb/help/326549/you-cannot-view-or-change-the-read-only-or-the-system-attributes-of-fo
+     *
+     */
+    if ((fMode & (RTFS_DOS_DIRECTORY | RTFS_DOS_READONLY)) != RTFS_DOS_READONLY)
+        fMode |= RTFS_UNIX_IWUSR | RTFS_UNIX_IWGRP | RTFS_UNIX_IWOTH;
+    return fMode;
+}
+
+
+/**
+ * Converts Unix attributes to Dos-style attributes.
+ *
+ * @returns File mode mask.
+ * @param   fMode       The mode mask containing dos-style attributes only.
+ * @param   pszName     The filename which this applies to (hidden check).
+ * @param   cbName      The length of that filename. (optional, set 0)
+ * @param   fType       RTFS_TYPE_XXX to normalize against, 0 if not known.
+ */
+RTFMODE rtFsModeFromUnix(RTFMODE fMode, const char *pszName, size_t cbName, RTFMODE fType)
+{
+    Assert(!(fType & ~RTFS_TYPE_MASK));
+    NOREF(cbName);
+
+    fMode &= RTFS_UNIX_MASK;
+
+    if (!(fType & RTFS_TYPE_MASK) && fType)
+        fMode |= fType;
+
+    if (!(fMode & (RTFS_UNIX_IWUSR | RTFS_UNIX_IWGRP | RTFS_UNIX_IWOTH)))
+        fMode |= RTFS_DOS_READONLY;
+    if (RTFS_IS_DIRECTORY(fMode))
+        fMode |= RTFS_DOS_DIRECTORY;
+    if (!(fMode & RTFS_DOS_MASK))
+        fMode |= RTFS_DOS_NT_NORMAL;
+    if (!(fMode & RTFS_DOS_HIDDEN) && pszName)
+    {
+        pszName = RTPathFilename(pszName);
+        if (   pszName
+            && pszName[0] == '.'
+            && pszName[1] != '\0' /* exclude "." */
+            && (pszName[1] != '.' || pszName[2] != '\0')) /* exclude ".." */
+            fMode |= RTFS_DOS_HIDDEN;
+    }
+    return fMode;
+}
+
+
+/**
+ * Normalizes the give mode mask.
+ *
+ * It will create the missing unix or dos mask from the other (one
+ * of them is required by all APIs), and guess the file type if that's
+ * missing.
+ *
+ * @returns Normalized file mode.
+ * @param   fMode       The mode mask that may contain a partial/incomplete mask.
+ * @param   pszName     The filename which this applies to (exe check).
+ * @param   cbName      The length of that filename. (optional, set 0)
+ * @param   fType       RTFS_TYPE_XXX to normalize against, 0 if not known.
+ */
+RTFMODE rtFsModeNormalize(RTFMODE fMode, const char *pszName, size_t cbName, RTFMODE fType)
+{
+    Assert(!(fType & ~RTFS_TYPE_MASK));
+
+    if (!(fMode & RTFS_UNIX_MASK))
+        fMode = rtFsModeFromDos(fMode, pszName, cbName, RTFSMODE_SYMLINK_REPARSE_TAG, fType);
+    else if (!(fMode & RTFS_DOS_MASK))
+        fMode = rtFsModeFromUnix(fMode, pszName, cbName, fType);
+    else if (!(fMode & RTFS_TYPE_MASK))
+        fMode |= fMode & RTFS_DOS_DIRECTORY ? RTFS_TYPE_DIRECTORY : RTFS_TYPE_FILE;
+    else if (RTFS_IS_DIRECTORY(fMode))
+        fMode |= RTFS_DOS_DIRECTORY;
+    return fMode;
+}
+
+
+/**
+ * Checks if the file mode is valid or not.
+ *
+ * @return  true if valid.
+ * @return  false if invalid, done bitching.
+ * @param   fMode       The file mode.
+ */
+bool rtFsModeIsValid(RTFMODE fMode)
+{
+    AssertMsgReturn(   (!RTFS_IS_DIRECTORY(fMode) && !(fMode & RTFS_DOS_DIRECTORY))
+                    || (RTFS_IS_DIRECTORY(fMode) && (fMode & RTFS_DOS_DIRECTORY)),
+                    ("%RTfmode\n", fMode), false);
+    AssertMsgReturn(RTFS_TYPE_MASK & fMode,
+                    ("%RTfmode\n", fMode), false);
+    /** @todo more checks! */
+    return true;
+}
+
+
+/**
+ * Checks if the file mode is valid as a permission mask or not.
+ *
+ * @return  true if valid.
+ * @return  false if invalid, done bitching.
+ * @param   fMode       The file mode.
+ */
+bool rtFsModeIsValidPermissions(RTFMODE fMode)
+{
+    AssertMsgReturn(   (!RTFS_IS_DIRECTORY(fMode) && !(fMode & RTFS_DOS_DIRECTORY))
+                    || (RTFS_IS_DIRECTORY(fMode) && (fMode & RTFS_DOS_DIRECTORY)),
+                    ("%RTfmode\n", fMode), false);
+    /** @todo more checks! */
+    return true;
+}
+
+
+RTDECL(const char *) RTFsTypeName(RTFSTYPE enmType)
+{
+    switch (enmType)
+    {
+        case RTFSTYPE_UNKNOWN:      return "unknown";
+        case RTFSTYPE_UDF:          return "udf";
+        case RTFSTYPE_ISO9660:      return "iso9660";
+        case RTFSTYPE_FUSE:         return "fuse";
+        case RTFSTYPE_VBOXSHF:      return "vboxshf";
+
+        case RTFSTYPE_EXT:          return "ext";
+        case RTFSTYPE_EXT2:         return "ext2";
+        case RTFSTYPE_EXT3:         return "ext3";
+        case RTFSTYPE_EXT4:         return "ext4";
+        case RTFSTYPE_XFS:          return "xfs";
+        case RTFSTYPE_CIFS:         return "cifs";
+        case RTFSTYPE_SMBFS:        return "smbfs";
+        case RTFSTYPE_TMPFS:        return "tmpfs";
+        case RTFSTYPE_SYSFS:        return "sysfs";
+        case RTFSTYPE_PROC:         return "proc";
+        case RTFSTYPE_OCFS2:        return "ocfs2";
+        case RTFSTYPE_BTRFS:        return "btrfs";
+
+        case RTFSTYPE_NTFS:         return "ntfs";
+        case RTFSTYPE_FAT:          return "fat";
+        case RTFSTYPE_EXFAT:        return "exfat";
+        case RTFSTYPE_REFS:         return "refs";
+
+        case RTFSTYPE_ZFS:          return "zfs";
+        case RTFSTYPE_UFS:          return "ufs";
+        case RTFSTYPE_NFS:          return "nfs";
+
+        case RTFSTYPE_HFS:          return "hfs";
+        case RTFSTYPE_APFS:         return "apfs";
+        case RTFSTYPE_AUTOFS:       return "autofs";
+        case RTFSTYPE_DEVFS:        return "devfs";
+
+        case RTFSTYPE_HPFS:         return "hpfs";
+        case RTFSTYPE_JFS:          return "jfs";
+
+        case RTFSTYPE_END:          return "end";
+        case RTFSTYPE_32BIT_HACK:   break;
+    }
+
+    /* Don't put this in as 'default:', we wish GCC to warn about missing cases. */
+    static char                 s_asz[4][64];
+    static uint32_t volatile    s_i = 0;
+    uint32_t i = ASMAtomicIncU32(&s_i) % RT_ELEMENTS(s_asz);
+    RTStrPrintf(s_asz[i], sizeof(s_asz[i]), "type=%d", enmType);
+    return s_asz[i];
+}
+
diff --git a/src/VBox/Runtime/r3/ftp-server.cpp b/src/VBox/Runtime/r3/ftp-server.cpp
new file mode 100644
index 00000000..425aad03
--- /dev/null
+++ b/src/VBox/Runtime/r3/ftp-server.cpp
@@ -0,0 +1,2589 @@
+/* $Id: ftp-server.cpp $ */
+/** @file
+ * Generic FTP server (RFC 959) implementation.
+ *
+ * Partly also implements RFC 3659 (Extensions to FTP, for "SIZE", ++).
+ *
+ * Known limitations so far:
+ * - UTF-8 support only.
+ * - Only supports ASCII + binary (image type) file streams for now.
+ * - No directory / file caching yet.
+ * - No support for writing / modifying ("DELE", "MKD", "RMD", "STOR", ++).
+ * - No FTPS / SFTP support.
+ * - No passive mode ("PASV") support.
+ * - No IPv6 support.
+ * - No proxy support.
+ * - No FXP support.
+ */
+
+/*
+ * Copyright (C) 2020-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FTP
+#include <iprt/ftp.h>
+#include "internal/iprt.h"
+#include "internal/magics.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/circbuf.h>
+#include <iprt/err.h>
+#include <iprt/file.h> /* For file mode flags. */
+#include <iprt/getopt.h>
+#include <iprt/mem.h>
+#include <iprt/log.h>
+#include <iprt/path.h>
+#include <iprt/poll.h>
+#include <iprt/socket.h>
+#include <iprt/sort.h>
+#include <iprt/string.h>
+#include <iprt/system.h>
+#include <iprt/tcp.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Internal FTP server instance.
+ */
+typedef struct RTFTPSERVERINTERNAL
+{
+    /** Magic value. */
+    uint32_t                u32Magic;
+    /** Callback table. */
+    RTFTPSERVERCALLBACKS    Callbacks;
+    /** Pointer to TCP server instance. */
+    PRTTCPSERVER            pTCPServer;
+    /** Number of currently connected clients. */
+    uint32_t                cClients;
+    /** Pointer to user-specific data. Optional. */
+    void                   *pvUser;
+    /** Size of user-specific data. Optional. */
+    size_t                  cbUser;
+} RTFTPSERVERINTERNAL;
+/** Pointer to an internal FTP server instance. */
+typedef RTFTPSERVERINTERNAL *PRTFTPSERVERINTERNAL;
+
+/**
+ * FTP directory entry.
+ */
+typedef struct RTFTPDIRENTRY
+{
+    /** The information about the entry. */
+    RTFSOBJINFO Info;
+    /** Symbolic link target (allocated after the name). */
+    const char *pszTarget;
+    /** Owner if applicable (allocated after the name). */
+    const char *pszOwner;
+    /** Group if applicable (allocated after the name). */
+    const char *pszGroup;
+    /** The length of szName. */
+    size_t      cchName;
+    /** The entry name. */
+    RT_FLEXIBLE_ARRAY_EXTENSION
+    char        szName[RT_FLEXIBLE_ARRAY];
+} RTFTPDIRENTRY;
+/** Pointer to a FTP directory entry. */
+typedef RTFTPDIRENTRY *PRTFTPDIRENTRY;
+/** Pointer to a FTP directory entry pointer. */
+typedef PRTFTPDIRENTRY *PPRTFTPDIRENTRY;
+
+/**
+ * Collection of directory entries.
+ * Used for also caching stuff.
+ */
+typedef struct RTFTPDIRCOLLECTION
+{
+    /** Current size of papEntries. */
+    size_t                cEntries;
+    /** Memory allocated for papEntries. */
+    size_t                cEntriesAllocated;
+    /** Current entries pending sorting and display. */
+    PPRTFTPDIRENTRY       papEntries;
+
+    /** Total number of bytes allocated for the above entries. */
+    uint64_t              cbTotalAllocated;
+    /** Total number of file content bytes.    */
+    uint64_t              cbTotalFiles;
+
+} RTFTPDIRCOLLECTION;
+/** Pointer to a directory collection. */
+typedef RTFTPDIRCOLLECTION *PRTFTPDIRCOLLECTION;
+/** Pointer to a directory entry collection pointer. */
+typedef PRTFTPDIRCOLLECTION *PPRTFTPDIRCOLLECTION;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Validates a handle and returns VERR_INVALID_HANDLE if not valid. */
+#define RTFTPSERVER_VALID_RETURN_RC(hFTPServer, a_rc) \
+    do { \
+        AssertPtrReturn((hFTPServer), (a_rc)); \
+        AssertReturn((hFTPServer)->u32Magic == RTFTPSERVER_MAGIC, (a_rc)); \
+    } while (0)
+
+/** Validates a handle and returns VERR_INVALID_HANDLE if not valid. */
+#define RTFTPSERVER_VALID_RETURN(hFTPServer) RTFTPSERVER_VALID_RETURN_RC((hFTPServer), VERR_INVALID_HANDLE)
+
+/** Validates a handle and returns (void) if not valid. */
+#define RTFTPSERVER_VALID_RETURN_VOID(hFTPServer) \
+    do { \
+        AssertPtrReturnVoid(hFTPServer); \
+        AssertReturnVoid((hFTPServer)->u32Magic == RTFTPSERVER_MAGIC); \
+    } while (0)
+
+
+/** Handles a FTP server callback with no arguments and returns. */
+#define RTFTPSERVER_HANDLE_CALLBACK_RET(a_Name) \
+    do \
+    { \
+        PRTFTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTFTPCALLBACKDATA Data = { &pClient->State }; \
+            return pCallbacks->a_Name(&Data); \
+        } \
+        return VERR_NOT_IMPLEMENTED; \
+    } while (0)
+
+/** Handles a FTP server callback with no arguments and sets rc accordingly. */
+#define RTFTPSERVER_HANDLE_CALLBACK(a_Name) \
+    do \
+    { \
+        PRTFTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTFTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            rc = pCallbacks->a_Name(&Data); \
+        } \
+        else \
+            rc = VERR_NOT_IMPLEMENTED; \
+    } while (0)
+
+/** Handles a FTP server callback with arguments and sets rc accordingly. */
+#define RTFTPSERVER_HANDLE_CALLBACK_VA(a_Name, ...) \
+    do \
+    { \
+        PRTFTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTFTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            rc = pCallbacks->a_Name(&Data, __VA_ARGS__); \
+        } \
+        else \
+            rc = VERR_NOT_IMPLEMENTED; \
+    } while (0)
+
+/** Handles a FTP server callback with arguments and returns. */
+#define RTFTPSERVER_HANDLE_CALLBACK_VA_RET(a_Name, ...) \
+    do \
+    { \
+        PRTFTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTFTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            return pCallbacks->a_Name(&Data, __VA_ARGS__); \
+        } \
+        return VERR_NOT_IMPLEMENTED; \
+    } while (0)
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Supported FTP server command IDs.
+ *  Alphabetically, named after their official command names. */
+typedef enum RTFTPSERVERCMD
+{
+    /** Invalid command, do not use. Always must come first. */
+    RTFTPSERVERCMD_INVALID = 0,
+    /** Aborts the current command on the server. */
+    RTFTPSERVERCMD_ABOR,
+    /** Changes the current working directory. */
+    RTFTPSERVERCMD_CDUP,
+    /** Changes the current working directory. */
+    RTFTPSERVERCMD_CWD,
+    /** Reports features supported by the server. */
+    RTFTPSERVERCMD_FEAT,
+    /** Lists a directory. */
+    RTFTPSERVERCMD_LIST,
+    /** Sets the transfer mode. */
+    RTFTPSERVERCMD_MODE,
+    /** Sends a nop ("no operation") to the server. */
+    RTFTPSERVERCMD_NOOP,
+    /** Sets the password for authentication. */
+    RTFTPSERVERCMD_PASS,
+    /** Sets the port to use for the data connection. */
+    RTFTPSERVERCMD_PORT,
+    /** Gets the current working directory. */
+    RTFTPSERVERCMD_PWD,
+    /** Get options. Needed in conjunction with the FEAT command. */
+    RTFTPSERVERCMD_OPTS,
+    /** Terminates the session (connection). */
+    RTFTPSERVERCMD_QUIT,
+    /** Retrieves a specific file. */
+    RTFTPSERVERCMD_RETR,
+    /** Retrieves the size of a file. */
+    RTFTPSERVERCMD_SIZE,
+    /** Retrieves the current status of a transfer. */
+    RTFTPSERVERCMD_STAT,
+    /** Sets the structure type to use. */
+    RTFTPSERVERCMD_STRU,
+    /** Gets the server's OS info. */
+    RTFTPSERVERCMD_SYST,
+    /** Sets the (data) representation type. */
+    RTFTPSERVERCMD_TYPE,
+    /** Sets the user name for authentication. */
+    RTFTPSERVERCMD_USER,
+    /** End marker. */
+    RTFTPSERVERCMD_END,
+    /** The usual 32-bit hack. */
+    RTFTPSERVERCMD_32BIT_HACK = 0x7fffffff
+} RTFTPSERVERCMD;
+
+struct RTFTPSERVERCLIENT;
+
+/**
+ * Structure for maintaining a single data connection.
+ */
+typedef struct RTFTPSERVERDATACONN
+{
+    /** Pointer to associated client of this data connection. */
+    RTFTPSERVERCLIENT          *pClient;
+    /** Data connection IP. */
+    RTNETADDRIPV4               Addr;
+    /** Data connection port number. */
+    uint16_t                    uPort;
+    /** The current data socket to use.
+     *  Can be NIL_RTSOCKET if no data port has been specified (yet) or has been closed. */
+    RTSOCKET                    hSocket;
+    /** Thread serving the data connection. */
+    RTTHREAD                    hThread;
+    /** Thread started indicator. */
+    volatile bool               fStarted;
+    /** Thread stop indicator. */
+    volatile bool               fStop;
+    /** Thread stopped indicator. */
+    volatile bool               fStopped;
+    /** Overall result when closing the data connection. */
+    int                         rc;
+    /** Number of command arguments. */
+    uint8_t                     cArgs;
+    /** Command arguments array. Optional and can be NULL.
+     *  Will be free'd by the data connection thread. */
+    char**                      papszArgs;
+    /** Circular buffer for caching data before writing. */
+    PRTCIRCBUF                  pCircBuf;
+} RTFTPSERVERDATACONN;
+/** Pointer to a data connection struct. */
+typedef RTFTPSERVERDATACONN *PRTFTPSERVERDATACONN;
+
+/**
+ * Structure for maintaining an internal FTP server client.
+ */
+typedef struct RTFTPSERVERCLIENT
+{
+    /** Pointer to internal server state. */
+    PRTFTPSERVERINTERNAL        pServer;
+    /** Socket handle the client is bound to. */
+    RTSOCKET                    hSocket;
+    /** Actual client state. */
+    RTFTPSERVERCLIENTSTATE      State;
+    /** The last set data connection IP. */
+    RTNETADDRIPV4               DataConnAddr;
+    /** The last set data connection port number. */
+    uint16_t                    uDataConnPort;
+    /** Data connection information.
+     *  At the moment we only allow one data connection per client at a time. */
+    PRTFTPSERVERDATACONN        pDataConn;
+} RTFTPSERVERCLIENT;
+/** Pointer to an internal FTP server client state. */
+typedef RTFTPSERVERCLIENT *PRTFTPSERVERCLIENT;
+
+/** Function pointer declaration for a specific FTP server command handler. */
+typedef DECLCALLBACKTYPE(int, FNRTFTPSERVERCMD,(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs));
+/** Pointer to a FNRTFTPSERVERCMD(). */
+typedef FNRTFTPSERVERCMD *PFNRTFTPSERVERCMD;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static int  rtFtpServerDataConnOpen(PRTFTPSERVERDATACONN pDataConn, PRTNETADDRIPV4 pAddr, uint16_t uPort);
+static int  rtFtpServerDataConnClose(PRTFTPSERVERDATACONN pDataConn);
+static void rtFtpServerDataConnReset(PRTFTPSERVERDATACONN pDataConn);
+static int  rtFtpServerDataConnStart(PRTFTPSERVERDATACONN pDataConn, PFNRTTHREAD pfnThread, uint8_t cArgs, const char * const *apszArgs);
+static int  rtFtpServerDataConnStop(PRTFTPSERVERDATACONN pDataConn);
+static void rtFtpServerDataConnDestroy(PRTFTPSERVERDATACONN pDataConn);
+static int  rtFtpServerDataConnFlush(PRTFTPSERVERDATACONN pDataConn);
+
+static void rtFtpServerClientStateReset(PRTFTPSERVERCLIENTSTATE pState);
+
+/** @name Command handlers.
+ * @{
+ */
+static FNRTFTPSERVERCMD rtFtpServerHandleABOR;
+static FNRTFTPSERVERCMD rtFtpServerHandleCDUP;
+static FNRTFTPSERVERCMD rtFtpServerHandleCWD;
+static FNRTFTPSERVERCMD rtFtpServerHandleFEAT;
+static FNRTFTPSERVERCMD rtFtpServerHandleLIST;
+static FNRTFTPSERVERCMD rtFtpServerHandleMODE;
+static FNRTFTPSERVERCMD rtFtpServerHandleNOOP;
+static FNRTFTPSERVERCMD rtFtpServerHandlePASS;
+static FNRTFTPSERVERCMD rtFtpServerHandlePORT;
+static FNRTFTPSERVERCMD rtFtpServerHandlePWD;
+static FNRTFTPSERVERCMD rtFtpServerHandleOPTS;
+static FNRTFTPSERVERCMD rtFtpServerHandleQUIT;
+static FNRTFTPSERVERCMD rtFtpServerHandleRETR;
+static FNRTFTPSERVERCMD rtFtpServerHandleSIZE;
+static FNRTFTPSERVERCMD rtFtpServerHandleSTAT;
+static FNRTFTPSERVERCMD rtFtpServerHandleSTRU;
+static FNRTFTPSERVERCMD rtFtpServerHandleSYST;
+static FNRTFTPSERVERCMD rtFtpServerHandleTYPE;
+static FNRTFTPSERVERCMD rtFtpServerHandleUSER;
+/** @} */
+
+/**
+ * Structure for maintaining a single command entry for the command table.
+ */
+typedef struct RTFTPSERVERCMD_ENTRY
+{
+    /** Command ID. */
+    RTFTPSERVERCMD      enmCmd;
+    /** Command represented as ASCII string. */
+    char                szCmd[RTFTPSERVER_MAX_CMD_LEN];
+    /** Whether the commands needs a logged in (valid) user. */
+    bool                fNeedsUser;
+    /** Function pointer invoked to handle the command. */
+    PFNRTFTPSERVERCMD   pfnCmd;
+} RTFTPSERVERCMD_ENTRY;
+/** Pointer to a command entry. */
+typedef RTFTPSERVERCMD_ENTRY *PRTFTPSERVERCMD_ENTRY;
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Table of handled commands.
+ */
+static const RTFTPSERVERCMD_ENTRY g_aCmdMap[] =
+{
+    { RTFTPSERVERCMD_ABOR,      "ABOR", true,  rtFtpServerHandleABOR },
+    { RTFTPSERVERCMD_CDUP,      "CDUP", true,  rtFtpServerHandleCDUP },
+    { RTFTPSERVERCMD_CWD,       "CWD",  true,  rtFtpServerHandleCWD  },
+    { RTFTPSERVERCMD_FEAT,      "FEAT", false, rtFtpServerHandleFEAT },
+    { RTFTPSERVERCMD_LIST,      "LIST", true,  rtFtpServerHandleLIST },
+    { RTFTPSERVERCMD_MODE,      "MODE", true,  rtFtpServerHandleMODE },
+    { RTFTPSERVERCMD_NOOP,      "NOOP", true,  rtFtpServerHandleNOOP },
+    { RTFTPSERVERCMD_PASS,      "PASS", false, rtFtpServerHandlePASS },
+    { RTFTPSERVERCMD_PORT,      "PORT", true,  rtFtpServerHandlePORT },
+    { RTFTPSERVERCMD_PWD,       "PWD",  true,  rtFtpServerHandlePWD  },
+    { RTFTPSERVERCMD_OPTS,      "OPTS", false, rtFtpServerHandleOPTS },
+    { RTFTPSERVERCMD_QUIT,      "QUIT", false, rtFtpServerHandleQUIT },
+    { RTFTPSERVERCMD_RETR,      "RETR", true,  rtFtpServerHandleRETR },
+    { RTFTPSERVERCMD_SIZE,      "SIZE", true,  rtFtpServerHandleSIZE },
+    { RTFTPSERVERCMD_STAT,      "STAT", true,  rtFtpServerHandleSTAT },
+    { RTFTPSERVERCMD_STRU,      "STRU", true,  rtFtpServerHandleSTRU },
+    { RTFTPSERVERCMD_SYST,      "SYST", false, rtFtpServerHandleSYST },
+    { RTFTPSERVERCMD_TYPE,      "TYPE", true,  rtFtpServerHandleTYPE },
+    { RTFTPSERVERCMD_USER,      "USER", false, rtFtpServerHandleUSER },
+    { RTFTPSERVERCMD_END,       "",     false, NULL }
+};
+
+/** RFC-1123 month of the year names. */
+static const char * const g_apszMonths[1+12] =
+{
+    "000", "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+};
+
+/** Feature string which represents all commands we support in addition to RFC 959 (see RFC 2398).
+ *  Must match the command table above.
+ *
+ *  Don't forget the beginning space (" ") at each feature. */
+#define RTFTPSERVER_FEATURES_STRING \
+    " SIZE\r\n" \
+    " UTF8"
+
+/** Maximum length in characters a FTP server path can have (excluding termination). */
+#define RTFTPSERVER_MAX_PATH        RTPATH_MAX
+
+
+/*********************************************************************************************************************************
+*   Protocol Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Replies a (three digit) reply code back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   enmReply            Reply code to send.
+ */
+static int rtFtpServerSendReplyRc(PRTFTPSERVERCLIENT pClient, RTFTPSERVER_REPLY enmReply)
+{
+    /* Note: If we don't supply any additional text, make sure to include an empty stub, as
+     *       some clients expect this as part of their parsing code. */
+    char szReply[32];
+    RTStrPrintf2(szReply, sizeof(szReply), "%RU32 -\r\n", enmReply);
+
+    LogFlowFunc(("Sending reply code %RU32\n", enmReply));
+
+    return RTTcpWrite(pClient->hSocket, szReply, strlen(szReply));
+}
+
+/**
+ * Replies a (three digit) reply code with a custom message back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   enmReply            Reply code to send.
+ * @param   pszFormat           Format string of message to send with the reply code.
+ */
+static int rtFtpServerSendReplyRcEx(PRTFTPSERVERCLIENT pClient, RTFTPSERVER_REPLY enmReply,
+                                    const char *pszFormat, ...)
+{
+    char *pszMsg = NULL;
+
+    va_list args;
+    va_start(args, pszFormat);
+    char *pszFmt = NULL;
+    const int cch = RTStrAPrintfV(&pszFmt, pszFormat, args);
+    va_end(args);
+    AssertReturn(cch > 0, VERR_NO_MEMORY);
+
+    int rc = RTStrAPrintf(&pszMsg, "%RU32 -", enmReply);
+    AssertRCReturn(rc, rc);
+
+    /** @todo Support multi-line replies (see 4.2ff). */
+
+    if (pszFmt)
+    {
+        rc = RTStrAAppend(&pszMsg, " ");
+        AssertRCReturn(rc, rc);
+
+        rc = RTStrAAppend(&pszMsg, pszFmt);
+        AssertRCReturn(rc, rc);
+    }
+
+
+    rc = RTStrAAppend(&pszMsg, "\r\n");
+    AssertRCReturn(rc, rc);
+
+    RTStrFree(pszFmt);
+
+    rc = RTTcpWrite(pClient->hSocket, pszMsg, strlen(pszMsg));
+
+    RTStrFree(pszMsg);
+
+    return rc;
+}
+
+/**
+ * Replies a string back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   pszFormat           Format to reply.
+ * @param   ...                 Format arguments.
+ */
+static int rtFtpServerSendReplyStr(PRTFTPSERVERCLIENT pClient, const char *pszFormat, ...)
+{
+    va_list args;
+    va_start(args, pszFormat);
+    char *psz = NULL;
+    const int cch = RTStrAPrintfV(&psz, pszFormat, args);
+    va_end(args);
+    AssertReturn(cch > 0, VERR_NO_MEMORY);
+
+    int rc = RTStrAAppend(&psz, "\r\n");
+    AssertRCReturn(rc, rc);
+
+    LogFlowFunc(("Sending reply '%s'\n", psz));
+
+    rc = RTTcpWrite(pClient->hSocket, psz, strlen(psz));
+
+    RTStrFree(psz);
+
+    return rc;
+}
+
+/**
+ * Validates if a given absolute path is valid or not.
+ *
+ * @returns \c true if path is valid, or \c false if not.
+ * @param   pszPath             Path to check.
+ * @param   fIsAbsolute         Whether the path to check is an absolute path or not.
+ */
+static bool rtFtpServerPathIsValid(const char *pszPath, bool fIsAbsolute)
+{
+    if (!pszPath)
+        return false;
+
+    bool fIsValid =    strlen(pszPath)
+                    && RTStrIsValidEncoding(pszPath)
+                    && RTStrStr(pszPath, "..") == NULL;     /** @todo Very crude for now -- improve this. */
+    if (   fIsValid
+        && fIsAbsolute)
+    {
+        RTFSOBJINFO objInfo;
+        int rc2 = RTPathQueryInfo(pszPath, &objInfo, RTFSOBJATTRADD_NOTHING);
+        if (RT_SUCCESS(rc2))
+        {
+            fIsValid =    RTFS_IS_DIRECTORY(objInfo.Attr.fMode)
+                       || RTFS_IS_FILE(objInfo.Attr.fMode);
+
+            /* No symlinks and other stuff not allowed. */
+        }
+        else
+            fIsValid = false;
+    }
+
+    LogFlowFunc(("pszPath=%s -> %RTbool\n", pszPath, fIsValid));
+    return fIsValid;
+}
+
+/**
+ * Sets the current working directory for a client.
+ *
+ * @returns VBox status code.
+ * @param   pState              Client state to set current working directory for.
+ * @param   pszPath             Working directory to set.
+ */
+static int rtFtpSetCWD(PRTFTPSERVERCLIENTSTATE pState, const char *pszPath)
+{
+    RTStrFree(pState->pszCWD);
+
+    if (!rtFtpServerPathIsValid(pszPath, false /* fIsAbsolute */))
+        return VERR_INVALID_PARAMETER;
+
+    pState->pszCWD = RTStrDup(pszPath);
+
+    LogFlowFunc(("Current CWD is now '%s'\n", pState->pszCWD));
+
+    int rc = pState->pszCWD ? VINF_SUCCESS : VERR_NO_MEMORY;
+    AssertRC(rc);
+    return rc;
+}
+
+/**
+ * Looks up an user account.
+ *
+ * @returns VBox status code, or VERR_NOT_FOUND if user has not been found.
+ * @param   pClient             Client to look up user for.
+ * @param   pszUser             User name to look up.
+ */
+static int rtFtpServerLookupUser(PRTFTPSERVERCLIENT pClient, const char *pszUser)
+{
+    RTFTPSERVER_HANDLE_CALLBACK_VA_RET(pfnOnUserConnect, pszUser);
+}
+
+/**
+ * Handles the actual client authentication.
+ *
+ * @returns VBox status code, or VERR_ACCESS_DENIED if authentication failed.
+ * @param   pClient             Client to authenticate.
+ * @param   pszUser             User name to authenticate with.
+ * @param   pszPassword         Password to authenticate with.
+ */
+static int rtFtpServerAuthenticate(PRTFTPSERVERCLIENT pClient, const char *pszUser, const char *pszPassword)
+{
+    RTFTPSERVER_HANDLE_CALLBACK_VA_RET(pfnOnUserAuthenticate, pszUser, pszPassword);
+}
+
+/**
+ * Converts a RTFSOBJINFO struct to a string.
+ *
+ * @returns VBox status code.
+ * @param   pObjInfo            RTFSOBJINFO object to convert.
+ * @param   pszFsObjInfo        Where to store the output string.
+ * @param   cbFsObjInfo         Size of the output string in bytes.
+ */
+static int rtFtpServerFsObjInfoToStr(PRTFSOBJINFO pObjInfo, char *pszFsObjInfo, size_t cbFsObjInfo)
+{
+    RTFMODE fMode = pObjInfo->Attr.fMode;
+    char chFileType;
+    switch (fMode & RTFS_TYPE_MASK)
+    {
+        case RTFS_TYPE_FIFO:        chFileType = 'f'; break;
+        case RTFS_TYPE_DEV_CHAR:    chFileType = 'c'; break;
+        case RTFS_TYPE_DIRECTORY:   chFileType = 'd'; break;
+        case RTFS_TYPE_DEV_BLOCK:   chFileType = 'b'; break;
+        case RTFS_TYPE_FILE:        chFileType = '-'; break;
+        case RTFS_TYPE_SYMLINK:     chFileType = 'l'; break;
+        case RTFS_TYPE_SOCKET:      chFileType = 's'; break;
+        case RTFS_TYPE_WHITEOUT:    chFileType = 'w'; break;
+        default:                    chFileType = '?'; break;
+    }
+
+    char szTimeBirth[RTTIME_STR_LEN];
+    char szTimeChange[RTTIME_STR_LEN];
+    char szTimeModification[RTTIME_STR_LEN];
+    char szTimeAccess[RTTIME_STR_LEN];
+
+#define INFO_TO_STR(a_Format, ...) \
+    do \
+    { \
+        const ssize_t cchSize = RTStrPrintf2(szTemp, sizeof(szTemp), a_Format, __VA_ARGS__); \
+        AssertReturn(cchSize > 0, VERR_BUFFER_OVERFLOW); \
+        const int rc2 = RTStrCat(pszFsObjInfo, cbFsObjInfo, szTemp); \
+        AssertRCReturn(rc2, rc2); \
+    } while (0);
+
+    char szTemp[128];
+
+    INFO_TO_STR("%c", chFileType);
+    INFO_TO_STR("%c%c%c",
+                fMode & RTFS_UNIX_IRUSR ? 'r' : '-',
+                fMode & RTFS_UNIX_IWUSR ? 'w' : '-',
+                fMode & RTFS_UNIX_IXUSR ? 'x' : '-');
+    INFO_TO_STR("%c%c%c",
+                fMode & RTFS_UNIX_IRGRP ? 'r' : '-',
+                fMode & RTFS_UNIX_IWGRP ? 'w' : '-',
+                fMode & RTFS_UNIX_IXGRP ? 'x' : '-');
+    INFO_TO_STR("%c%c%c",
+                fMode & RTFS_UNIX_IROTH ? 'r' : '-',
+                fMode & RTFS_UNIX_IWOTH ? 'w' : '-',
+                fMode & RTFS_UNIX_IXOTH ? 'x' : '-');
+
+    INFO_TO_STR( " %c%c%c%c%c%c%c%c%c%c%c%c%c%c",
+                fMode & RTFS_DOS_READONLY          ? 'R' : '-',
+                fMode & RTFS_DOS_HIDDEN            ? 'H' : '-',
+                fMode & RTFS_DOS_SYSTEM            ? 'S' : '-',
+                fMode & RTFS_DOS_DIRECTORY         ? 'D' : '-',
+                fMode & RTFS_DOS_ARCHIVED          ? 'A' : '-',
+                fMode & RTFS_DOS_NT_DEVICE         ? 'd' : '-',
+                fMode & RTFS_DOS_NT_NORMAL         ? 'N' : '-',
+                fMode & RTFS_DOS_NT_TEMPORARY      ? 'T' : '-',
+                fMode & RTFS_DOS_NT_SPARSE_FILE    ? 'P' : '-',
+                fMode & RTFS_DOS_NT_REPARSE_POINT  ? 'J' : '-',
+                fMode & RTFS_DOS_NT_COMPRESSED     ? 'C' : '-',
+                fMode & RTFS_DOS_NT_OFFLINE        ? 'O' : '-',
+                fMode & RTFS_DOS_NT_NOT_CONTENT_INDEXED ? 'I' : '-',
+                fMode & RTFS_DOS_NT_ENCRYPTED      ? 'E' : '-');
+
+    INFO_TO_STR( " %d %4d %4d %10lld %10lld",
+                pObjInfo->Attr.u.Unix.cHardlinks,
+                pObjInfo->Attr.u.Unix.uid,
+                pObjInfo->Attr.u.Unix.gid,
+                pObjInfo->cbObject,
+                pObjInfo->cbAllocated);
+
+    INFO_TO_STR( " %s %s %s %s",
+                RTTimeSpecToString(&pObjInfo->BirthTime,        szTimeBirth,        sizeof(szTimeBirth)),
+                RTTimeSpecToString(&pObjInfo->ChangeTime,       szTimeChange,       sizeof(szTimeChange)),
+                RTTimeSpecToString(&pObjInfo->ModificationTime, szTimeModification, sizeof(szTimeModification)),
+                RTTimeSpecToString(&pObjInfo->AccessTime,       szTimeAccess,       sizeof(szTimeAccess)) );
+
+#undef INFO_TO_STR
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Parses a string which consists of an IPv4 (ww,xx,yy,zz) and a port number (hi,lo), all separated by comma delimiters.
+ * See RFC 959, 4.1.2.
+ *
+ * @returns VBox status code.
+ * @param   pszStr              String to parse.
+ * @param   pAddr               Where to store the IPv4 address on success.
+ * @param   puPort              Where to store the port number on success.
+ */
+static int rtFtpParseHostAndPort(const char *pszStr, PRTNETADDRIPV4 pAddr, uint16_t *puPort)
+{
+    AssertPtrReturn(pszStr, VERR_INVALID_POINTER);
+    AssertPtrReturn(pAddr, VERR_INVALID_POINTER);
+    AssertPtrReturn(puPort, VERR_INVALID_POINTER);
+
+    char *pszNext;
+    int rc;
+
+    /* Parse IP (v4). */
+    /** @todo I don't think IPv6 ever will be a thing here, or will it? */
+    rc = RTStrToUInt8Ex(pszStr, &pszNext, 10, &pAddr->au8[0]);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+    if (*pszNext++ != ',')
+        return VERR_INVALID_PARAMETER;
+
+    rc = RTStrToUInt8Ex(pszNext, &pszNext, 10, &pAddr->au8[1]);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+    if (*pszNext++ != ',')
+        return VERR_INVALID_PARAMETER;
+
+    rc = RTStrToUInt8Ex(pszNext, &pszNext, 10, &pAddr->au8[2]);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+    if (*pszNext++ != ',')
+        return VERR_INVALID_PARAMETER;
+
+    rc = RTStrToUInt8Ex(pszNext, &pszNext, 10, &pAddr->au8[3]);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_SPACES && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+    if (*pszNext++ != ',')
+        return VERR_INVALID_PARAMETER;
+
+    /* Parse port. */
+    uint8_t uPortHi;
+    rc = RTStrToUInt8Ex(pszNext, &pszNext, 10, &uPortHi);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_SPACES && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+    if (*pszNext++ != ',')
+        return VERR_INVALID_PARAMETER;
+    uint8_t uPortLo;
+    rc = RTStrToUInt8Ex(pszNext, &pszNext, 10, &uPortLo);
+    if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_SPACES && rc != VWRN_TRAILING_CHARS)
+        return VERR_INVALID_PARAMETER;
+
+    *puPort = RT_MAKE_U16(uPortLo, uPortHi);
+
+    return rc;
+}
+
+/**
+ * Duplicates a command argument vector.
+ *
+ * @returns Duplicated argument vector or NULL if failed or no arguments given. Needs to be free'd with rtFtpCmdArgsFree().
+ * @param   cArgs               Number of arguments in argument vector.
+ * @param   apszArgs            Pointer to argument vector to duplicate.
+ */
+static char** rtFtpCmdArgsDup(uint8_t cArgs, const char * const *apszArgs)
+{
+    if (!cArgs)
+        return NULL;
+
+    char **apszArgsDup = (char **)RTMemAlloc(cArgs * sizeof(char *));
+    if (!apszArgsDup)
+    {
+        AssertFailed();
+        return NULL;
+    }
+
+    int rc2 = VINF_SUCCESS;
+
+    uint8_t i;
+    for (i = 0; i < cArgs; i++)
+    {
+        apszArgsDup[i] = RTStrDup(apszArgs[i]);
+        if (!apszArgsDup[i])
+            rc2 = VERR_NO_MEMORY;
+    }
+
+    if (RT_FAILURE(rc2))
+    {
+        while (i--)
+            RTStrFree(apszArgsDup[i]);
+
+        RTMemFree(apszArgsDup);
+        return NULL;
+    }
+
+    return apszArgsDup;
+}
+
+/**
+ * Frees a command argument vector.
+ *
+ * @param   cArgs               Number of arguments in argument vector.
+ * @param   papszArgs           Pointer to argument vector to free.
+ */
+static void rtFtpCmdArgsFree(uint8_t cArgs, char **papszArgs)
+{
+    while (cArgs--)
+        RTStrFree(papszArgs[cArgs]);
+
+    RTMemFree(papszArgs);
+}
+
+/**
+ * Opens a data connection to the client.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to open.
+ * @param   pAddr               Address for the data connection.
+ * @param   uPort               Port for the data connection.
+ */
+static int rtFtpServerDataConnOpen(PRTFTPSERVERDATACONN pDataConn, PRTNETADDRIPV4 pAddr, uint16_t uPort)
+{
+    LogFlowFuncEnter();
+
+    /** @todo Implement IPv6 handling here. */
+    char szAddress[32];
+    const ssize_t cchAdddress = RTStrPrintf2(szAddress, sizeof(szAddress), "%RU8.%RU8.%RU8.%RU8",
+                                             pAddr->au8[0], pAddr->au8[1], pAddr->au8[2], pAddr->au8[3]);
+    AssertReturn(cchAdddress > 0, VERR_NO_MEMORY);
+
+    int rc = VINF_SUCCESS; /* Shut up MSVC. */
+
+    /* Try a bit harder if the data connection is not ready (yet). */
+    for (int i = 0; i < 10; i++)
+    {
+        rc = RTTcpClientConnect(szAddress, uPort, &pDataConn->hSocket);
+        if (RT_SUCCESS(rc))
+            break;
+        RTThreadSleep(100);
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Closes a data connection to the client.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to close.
+ */
+static int rtFtpServerDataConnClose(PRTFTPSERVERDATACONN pDataConn)
+{
+    int rc = VINF_SUCCESS;
+
+    if (pDataConn->hSocket != NIL_RTSOCKET)
+    {
+        LogFlowFuncEnter();
+
+        rtFtpServerDataConnFlush(pDataConn);
+
+        rc = RTTcpClientClose(pDataConn->hSocket);
+        pDataConn->hSocket = NIL_RTSOCKET;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Writes data to the data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to write to.
+ * @param   pvData              Data to write.
+ * @param   cbData              Size (in bytes) of data to write.
+ * @param   pcbWritten          How many bytes were written. Optional.
+ */
+static int rtFtpServerDataConnWrite(PRTFTPSERVERDATACONN pDataConn, const void *pvData, size_t cbData, size_t *pcbWritten)
+{
+    int rc = RTTcpWrite(pDataConn->hSocket, pvData, cbData);
+    if (RT_SUCCESS(rc))
+    {
+        if (pcbWritten)
+            *pcbWritten = cbData;
+    }
+
+    return rc;
+}
+
+/**
+ * Flushes a data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to flush.
+ */
+static int rtFtpServerDataConnFlush(PRTFTPSERVERDATACONN pDataConn)
+{
+    int rc = VINF_SUCCESS;
+
+    size_t cbUsed = RTCircBufUsed(pDataConn->pCircBuf);
+    while (cbUsed)
+    {
+        void   *pvBlock;
+        size_t  cbBlock;
+        RTCircBufAcquireReadBlock(pDataConn->pCircBuf, cbUsed, &pvBlock, &cbBlock);
+        if (cbBlock)
+        {
+            size_t cbWritten = 0;
+            rc = rtFtpServerDataConnWrite(pDataConn, pvBlock, cbBlock, &cbWritten);
+            if (RT_SUCCESS(rc))
+            {
+                AssertBreak(cbUsed >= cbWritten);
+                cbUsed -= cbWritten;
+            }
+
+            RTCircBufReleaseReadBlock(pDataConn->pCircBuf, cbWritten);
+
+            if (RT_FAILURE(rc))
+                break;
+        }
+    }
+
+    return rc;
+}
+
+/**
+ * Checks if flushing a data connection is necessary, and if so, flush it.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to check / do flushing for.
+ */
+static int rtFtpServerDataCheckFlush(PRTFTPSERVERDATACONN pDataConn)
+{
+    int rc = VINF_SUCCESS;
+
+    size_t cbUsed = RTCircBufUsed(pDataConn->pCircBuf);
+    if (cbUsed >= _4K) /** @todo Make this more dynamic. */
+    {
+        rc = rtFtpServerDataConnFlush(pDataConn);
+    }
+
+    return rc;
+}
+
+/**
+ * Adds new data for a data connection to be sent.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to add new data to.
+ * @param   pvData              Pointer to data to add.
+ * @param   cbData              Size (in bytes) of data to add.
+ */
+static int rtFtpServerDataConnAddData(PRTFTPSERVERDATACONN pDataConn, const void *pvData, size_t cbData)
+{
+    AssertReturn(cbData <= RTCircBufFree(pDataConn->pCircBuf), VERR_BUFFER_OVERFLOW);
+
+    int rc = VINF_SUCCESS;
+
+    size_t cbToWrite = cbData;
+    do
+    {
+        void   *pvBlock;
+        size_t  cbBlock;
+        RTCircBufAcquireWriteBlock(pDataConn->pCircBuf, cbToWrite, &pvBlock, &cbBlock);
+        if (cbBlock)
+        {
+            AssertBreak(cbData >= cbBlock);
+            memcpy(pvBlock, pvData, cbBlock);
+
+            AssertBreak(cbToWrite >= cbBlock);
+            cbToWrite -= cbBlock;
+
+            RTCircBufReleaseWriteBlock(pDataConn->pCircBuf, cbBlock);
+        }
+
+    } while (cbToWrite);
+
+    if (RT_SUCCESS(rc))
+        rc = rtFtpServerDataCheckFlush(pDataConn);
+
+    return rc;
+}
+
+/**
+ * Does a printf-style write on a data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to write to.
+ * @param   pszFormat           Format string to send. No (terminal) termination added.
+ */
+static int rtFtpServerDataConnPrintf(PRTFTPSERVERDATACONN pDataConn, const char *pszFormat, ...)
+{
+    va_list args;
+    va_start(args, pszFormat);
+    char *pszFmt = NULL;
+    const int cch = RTStrAPrintfV(&pszFmt, pszFormat, args);
+    va_end(args);
+    AssertReturn(cch > 0, VERR_NO_MEMORY);
+
+    char *pszMsg = NULL;
+    int rc = RTStrAAppend(&pszMsg, pszFmt);
+    AssertRCReturn(rc, rc);
+
+    RTStrFree(pszFmt);
+
+    rc = rtFtpServerDataConnAddData(pDataConn, pszMsg, strlen(pszMsg));
+
+    RTStrFree(pszMsg);
+
+    return rc;
+}
+
+/**
+ * Data connection thread for writing (sending) a file to the client.
+ *
+ * @returns VBox status code.
+ * @param   ThreadSelf          Thread handle. Unused at the moment.
+ * @param   pvUser              Pointer to user-provided data. Of type PRTFTPSERVERCLIENT.
+ */
+static DECLCALLBACK(int) rtFtpServerDataConnFileWriteThread(RTTHREAD ThreadSelf, void *pvUser)
+{
+    RT_NOREF(ThreadSelf);
+
+    PRTFTPSERVERCLIENT pClient = (PRTFTPSERVERCLIENT)pvUser;
+    AssertPtr(pClient);
+
+    PRTFTPSERVERDATACONN pDataConn = pClient->pDataConn;
+    AssertPtr(pDataConn);
+
+    LogFlowFuncEnter();
+
+    uint32_t cbBuf = _64K; /** @todo Improve this. */
+    void *pvBuf = RTMemAlloc(cbBuf);
+    if (!pvBuf)
+        return VERR_NO_MEMORY;
+
+    int rc;
+
+    /* Set start indicator. */
+    pDataConn->fStarted = true;
+
+    RTThreadUserSignal(RTThreadSelf());
+
+    AssertPtr(pDataConn->papszArgs);
+    const char *pszFile = pDataConn->papszArgs[0];
+    AssertPtr(pszFile);
+
+    void *pvHandle = NULL; /* Opaque handle known to the actual implementation. */
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileOpen, pszFile,
+                                   RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE, &pvHandle);
+    if (RT_SUCCESS(rc))
+    {
+        LogFlowFunc(("Transfer started\n"));
+
+        do
+        {
+            size_t cbRead = 0;
+            RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileRead, pvHandle, pvBuf, cbBuf, &cbRead);
+            if (   RT_SUCCESS(rc)
+                && cbRead)
+            {
+                rc = rtFtpServerDataConnWrite(pDataConn, pvBuf, cbRead, NULL /* pcbWritten */);
+            }
+
+            if (   !cbRead
+                || ASMAtomicReadBool(&pDataConn->fStop))
+            {
+                break;
+            }
+        }
+        while (RT_SUCCESS(rc));
+
+        RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileClose, pvHandle);
+
+        LogFlowFunc(("Transfer done\n"));
+    }
+
+    RTMemFree(pvBuf);
+    pvBuf = NULL;
+
+    pDataConn->fStopped = true;
+    pDataConn->rc       = rc;
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Creates a data connection.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to create data connection for.
+ * @param   ppDataConn          Where to return the (allocated) data connection.
+ */
+static int rtFtpServerDataConnCreate(PRTFTPSERVERCLIENT pClient, PRTFTPSERVERDATACONN *ppDataConn)
+{
+    if (pClient->pDataConn)
+        return VERR_FTP_DATA_CONN_LIMIT_REACHED;
+
+    PRTFTPSERVERDATACONN pDataConn = (PRTFTPSERVERDATACONN)RTMemAllocZ(sizeof(RTFTPSERVERDATACONN));
+    if (!pDataConn)
+        return VERR_NO_MEMORY;
+
+    rtFtpServerDataConnReset(pDataConn);
+
+    pDataConn->pClient = pClient;
+
+    /* Use the last configured addr + port. */
+    pDataConn->Addr    = pClient->DataConnAddr;
+    pDataConn->uPort   = pClient->uDataConnPort;
+
+    int rc = RTCircBufCreate(&pDataConn->pCircBuf, _16K); /** @todo Some random value; improve. */
+    if (RT_SUCCESS(rc))
+    {
+        *ppDataConn = pDataConn;
+    }
+
+    LogFlowFuncLeaveRC(VINF_SUCCESS);
+    return rc;
+}
+
+/**
+ * Starts a data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to start.
+ * @param   pfnThread           Thread function for the data connection to use.
+ * @param   cArgs               Number of arguments.
+ * @param   apszArgs            Array of arguments.
+ */
+static int rtFtpServerDataConnStart(PRTFTPSERVERDATACONN pDataConn, PFNRTTHREAD pfnThread,
+                                    uint8_t cArgs, const char * const *apszArgs)
+{
+    AssertPtrReturn(pDataConn, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfnThread, VERR_INVALID_POINTER);
+
+    AssertReturn(!pDataConn->fStarted, VERR_WRONG_ORDER);
+    AssertReturn(!pDataConn->fStop,    VERR_WRONG_ORDER);
+    AssertReturn(!pDataConn->fStopped, VERR_WRONG_ORDER);
+
+    int rc = VINF_SUCCESS;
+
+    if (cArgs)
+    {
+        pDataConn->papszArgs = rtFtpCmdArgsDup(cArgs, apszArgs);
+        if (!pDataConn->papszArgs)
+            rc = VERR_NO_MEMORY;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        pDataConn->cArgs = cArgs;
+
+        rc = rtFtpServerDataConnOpen(pDataConn, &pDataConn->Addr, pDataConn->uPort);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTThreadCreate(&pDataConn->hThread, pfnThread,
+                                pDataConn->pClient, 0, RTTHREADTYPE_DEFAULT, RTTHREADFLAGS_WAITABLE,
+                                "ftpdata");
+            if (RT_SUCCESS(rc))
+            {
+                int rc2 = RTThreadUserWait(pDataConn->hThread, 30 * 1000 /* Timeout in ms */);
+                AssertRC(rc2);
+
+                if (!pDataConn->fStarted) /* Did the thread indicate that it started correctly? */
+                    rc = VERR_FTP_DATA_CONN_INIT_FAILED;
+            }
+
+            if (RT_FAILURE(rc))
+                rtFtpServerDataConnClose(pDataConn);
+        }
+    }
+
+    if (RT_FAILURE(rc))
+    {
+        rtFtpCmdArgsFree(pDataConn->cArgs, pDataConn->papszArgs);
+
+        pDataConn->cArgs     = 0;
+        pDataConn->papszArgs = NULL;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Stops a data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to stop.
+ */
+static int rtFtpServerDataConnStop(PRTFTPSERVERDATACONN pDataConn)
+{
+    if (!pDataConn)
+        return VINF_SUCCESS;
+
+    LogFlowFuncEnter();
+
+    int rc = VINF_SUCCESS;
+
+    if (pDataConn->hThread != NIL_RTTHREAD)
+    {
+        /* Set stop indicator. */
+        pDataConn->fStop = true;
+
+        int rcThread = VERR_WRONG_ORDER;
+        rc = RTThreadWait(pDataConn->hThread, 30 * 1000 /* Timeout in ms */, &rcThread);
+    }
+
+    if (RT_SUCCESS(rc))
+        rtFtpServerDataConnClose(pDataConn);
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Destroys a data connection.
+ *
+ * @param   pDataConn           Data connection to destroy. The pointer is not valid anymore after successful return.
+ */
+static void rtFtpServerDataConnDestroy(PRTFTPSERVERDATACONN pDataConn)
+{
+    if (!pDataConn)
+        return;
+
+    LogFlowFuncEnter();
+
+    rtFtpServerDataConnClose(pDataConn);
+    rtFtpCmdArgsFree(pDataConn->cArgs, pDataConn->papszArgs);
+
+    RTCircBufDestroy(pDataConn->pCircBuf);
+
+    RTMemFree(pDataConn);
+    pDataConn = NULL;
+
+    LogFlowFuncLeave();
+    return;
+}
+
+/**
+ * Resets a data connection structure.
+ *
+ * @param   pDataConn           Data connection structure to reset.
+ */
+static void rtFtpServerDataConnReset(PRTFTPSERVERDATACONN pDataConn)
+{
+    LogFlowFuncEnter();
+
+    pDataConn->hSocket  = NIL_RTSOCKET;
+    pDataConn->uPort    = 20; /* Default port to use. */
+    pDataConn->hThread  = NIL_RTTHREAD;
+    pDataConn->fStarted = false;
+    pDataConn->fStop    = false;
+    pDataConn->fStopped = false;
+    pDataConn->rc       = VERR_IPE_UNINITIALIZED_STATUS;
+}
+
+
+/*********************************************************************************************************************************
+*   Command Protocol Handlers                                                                                                    *
+*********************************************************************************************************************************/
+
+static DECLCALLBACK(int) rtFtpServerHandleABOR(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc = rtFtpServerDataConnClose(pClient->pDataConn);
+    if (RT_SUCCESS(rc))
+    {
+        rtFtpServerDataConnDestroy(pClient->pDataConn);
+        pClient->pDataConn = NULL;
+
+        rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleCDUP(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc;
+
+    RTFTPSERVER_HANDLE_CALLBACK(pfnOnPathUp);
+
+    if (RT_SUCCESS(rc))
+    {
+        const size_t cbPath   = sizeof(char) * RTFTPSERVER_MAX_PATH;
+        char        *pszPath  = RTStrAlloc(cbPath);
+        if (pszPath)
+        {
+            RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnPathGetCurrent, pszPath, cbPath);
+
+            if (RT_SUCCESS(rc))
+                rc = rtFtpSetCWD(&pClient->State, pszPath);
+
+            RTStrFree(pszPath);
+
+            rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    if (RT_FAILURE(rc))
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+        AssertRC(rc2);
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleCWD(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    int rc;
+
+    const char *pszPath = apszArgs[0];
+
+    if (!rtFtpServerPathIsValid(pszPath, false /* fIsAbsolute */))
+        return VERR_INVALID_PARAMETER;
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnPathSetCurrent, pszPath);
+
+    if (RT_SUCCESS(rc))
+        rc = rtFtpSetCWD(&pClient->State, pszPath);
+
+    return rtFtpServerSendReplyRc(pClient,
+                                    RT_SUCCESS(rc)
+                                  ? RTFTPSERVER_REPLY_OKAY : RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleFEAT(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc = rtFtpServerSendReplyStr(pClient, "211-BEGIN Features:");
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtFtpServerSendReplyStr(pClient, RTFTPSERVER_FEATURES_STRING);
+        if (RT_SUCCESS(rc))
+            rc = rtFtpServerSendReplyStr(pClient, "211 END Features");
+    }
+
+    return rc;
+}
+
+/**
+ * Formats the given user ID according to the specified options.
+ *
+ * @returns pszDst
+ * @param   uid             The UID to format.
+ * @param   pszOwner        The owner returned by the FS.
+ * @param   pszDst          The output buffer.
+ * @param   cbDst           The output buffer size.
+ */
+static const char *rtFtpServerDecimalFormatOwner(RTUID uid, const char *pszOwner, char *pszDst, size_t cbDst)
+{
+    if (pszOwner)
+    {
+        RTStrCopy(pszDst, cbDst, pszOwner);
+        return pszDst;
+    }
+    if (uid == NIL_RTUID)
+        return "<Nil>";
+
+    RTStrFormatU64(pszDst, cbDst, uid, 10, 0, 0, 0);
+    return pszDst;
+}
+
+/**
+ * Formats the given group ID according to the specified options.
+ *
+ * @returns pszDst
+ * @param   gid             The GID to format.
+ * @param   pszGroup        The group returned by the FS.
+ * @param   pszDst          The output buffer.
+ * @param   cbDst           The output buffer size.
+ */
+static const char *rtFtpServerDecimalFormatGroup(RTGID gid, const char *pszGroup, char *pszDst, size_t cbDst)
+{
+    if (pszGroup)
+    {
+        RTStrCopy(pszDst, cbDst, pszGroup);
+        return pszDst;
+    }
+    if (gid == NIL_RTGID)
+        return "<Nil>";
+
+    RTStrFormatU64(pszDst, cbDst, gid, 10, 0, 0, 0);
+    return pszDst;
+}
+
+/**
+ * Format file size.
+ */
+static const char *rtFtpServerFormatSize(uint64_t cb, char *pszDst, size_t cbDst)
+{
+    RTStrFormatU64(pszDst, cbDst, cb, 10, 0, 0, 0);
+    return pszDst;
+}
+
+/**
+ * Formats the given timestamp according to (non-standardized) FTP LIST command.
+ *
+ * @returns pszDst
+ * @param   pTimestamp      The timestamp to format.
+ * @param   pszDst          The output buffer.
+ * @param   cbDst           The output buffer size.
+ */
+static const char *rtFtpServerFormatTimestamp(PCRTTIMESPEC pTimestamp, char *pszDst, size_t cbDst)
+{
+    RTTIME Time;
+    RTTimeExplode(&Time, pTimestamp);
+
+    /* Calc the UTC offset part. */
+    int32_t offUtc = Time.offUTC;
+    Assert(offUtc <= 840 && offUtc >= -840);
+    char     chSign;
+    if (offUtc >= 0)
+        chSign = '+';
+    else
+    {
+        chSign = '-';
+        offUtc = -offUtc;
+    }
+    uint32_t offUtcHour   = (uint32_t)offUtc / 60;
+    uint32_t offUtcMinute = (uint32_t)offUtc % 60;
+
+    /** @todo Cache this. */
+    RTTIMESPEC TimeSpecNow;
+    RTTimeNow(&TimeSpecNow);
+    RTTIME TimeNow;
+    RTTimeExplode(&TimeNow, &TimeSpecNow);
+
+    /* Only include the year if it's not the same year as today. */
+    if (TimeNow.i32Year != Time.i32Year)
+    {
+        RTStrPrintf(pszDst, cbDst, "%s  %02RU8  %5RU32",
+                    g_apszMonths[Time.u8Month], Time.u8MonthDay, Time.i32Year);
+    }
+    else /* ... otherwise include the (rough) time (as GMT). */
+    {
+        RTStrPrintf(pszDst, cbDst, "%s  %02RU8  %02RU32:%02RU32",
+                    g_apszMonths[Time.u8Month], Time.u8MonthDay, offUtcHour, offUtcMinute);
+    }
+
+    return pszDst;
+}
+
+/**
+ * Format name, i.e. escape, hide, quote stuff.
+ */
+static const char *rtFtpServerFormatName(const char *pszName, char *pszDst, size_t cbDst)
+{
+    /** @todo implement name formatting.   */
+    RT_NOREF(pszDst, cbDst);
+    return pszName;
+}
+
+/**
+ * Figures out the length for a 32-bit number when formatted as decimal.
+ * @returns Number of digits.
+ * @param   uValue              The number.
+ */
+DECLINLINE(size_t) rtFtpServerDecimalFormatLengthU32(uint32_t uValue)
+{
+    if (uValue < 10)
+        return 1;
+    if (uValue < 100)
+        return 2;
+    if (uValue < 1000)
+        return 3;
+    if (uValue < 10000)
+        return 4;
+    if (uValue < 100000)
+        return 5;
+    if (uValue < 1000000)
+        return 6;
+    if (uValue < 10000000)
+        return 7;
+    if (uValue < 100000000)
+        return 8;
+    if (uValue < 1000000000)
+        return 9;
+    return 10;
+}
+
+/**
+ * Allocates a new directory collection.
+ *
+ * @returns The collection allocated.
+ */
+static PRTFTPDIRCOLLECTION rtFtpServerDataConnDirCollAlloc(void)
+{
+    return (PRTFTPDIRCOLLECTION)RTMemAllocZ(sizeof(RTFTPDIRCOLLECTION));
+}
+
+/**
+ * Frees a directory collection and its entries.
+ *
+ * @param   pCollection         The collection to free.
+ */
+static void rtFtpServerDataConnDirCollFree(PRTFTPDIRCOLLECTION pCollection)
+{
+    PPRTFTPDIRENTRY    papEntries  = pCollection->papEntries;
+    size_t             j           = pCollection->cEntries;
+    while (j-- > 0)
+    {
+        RTMemFree(papEntries[j]);
+        papEntries[j] = NULL;
+    }
+    RTMemFree(papEntries);
+    pCollection->papEntries        = NULL;
+    pCollection->cEntries          = 0;
+    pCollection->cEntriesAllocated = 0;
+    RTMemFree(pCollection);
+}
+
+/**
+ * Adds one entry to a collection.
+ *
+ * @returns VBox status code.
+ * @param   pCollection         The collection to add entry to.
+ * @param   pszEntry            The entry name.
+ * @param   pInfo               The entry info.
+ * @param   pszOwner            The owner name if available, otherwise NULL.
+ * @param   pszGroup            The group anme if available, otherwise NULL.
+ * @param   pszTarget           The symbolic link target if applicable and
+ *                              available, otherwise NULL.
+ */
+static int rtFtpServerDataConnDirCollAddEntry(PRTFTPDIRCOLLECTION pCollection, const char *pszEntry, PRTFSOBJINFO pInfo,
+                                              const char *pszOwner, const char *pszGroup, const char *pszTarget)
+{
+    /* Filter out entries we don't want to report to the client, even if they were reported by the actual implementation. */
+    if (   !RTStrCmp(pszEntry, ".")
+        || !RTStrCmp(pszEntry, ".."))
+    {
+        return VINF_SUCCESS;
+    }
+
+    /* Anything else besides files and directores is not allowed; just don't show them at all for the moment. */
+    switch (pInfo->Attr.fMode & RTFS_TYPE_MASK)
+    {
+        case RTFS_TYPE_DIRECTORY:
+            RT_FALL_THROUGH();
+        case RTFS_TYPE_FILE:
+            break;
+
+        default:
+            return VINF_SUCCESS;
+    }
+
+    /* Make sure there is space in the collection for the new entry. */
+    if (pCollection->cEntries >= pCollection->cEntriesAllocated)
+    {
+        size_t cNew = pCollection->cEntriesAllocated ? pCollection->cEntriesAllocated * 2 : 16;
+        void *pvNew = RTMemRealloc(pCollection->papEntries, cNew * sizeof(pCollection->papEntries[0]));
+        if (!pvNew)
+            return VERR_NO_MEMORY;
+        pCollection->papEntries        = (PPRTFTPDIRENTRY)pvNew;
+        pCollection->cEntriesAllocated = cNew;
+    }
+
+    /* Create and insert a new entry. */
+    size_t const cchEntry = strlen(pszEntry);
+    size_t const cbOwner  = pszOwner  ? strlen(pszOwner)  + 1 : 0;
+    size_t const cbGroup  = pszGroup  ? strlen(pszGroup)  + 1 : 0;
+    size_t const cbTarget = pszTarget ? strlen(pszTarget) + 1 : 0;
+    size_t const cbEntry  = RT_UOFFSETOF_DYN(RTFTPDIRENTRY, szName[cchEntry + 1 + cbOwner + cbGroup + cbTarget]);
+    PRTFTPDIRENTRY pEntry = (PRTFTPDIRENTRY)RTMemAlloc(cbEntry);
+    if (pEntry)
+    {
+        pEntry->Info      = *pInfo;
+        pEntry->pszTarget = NULL; /** @todo symbolic links. */
+        pEntry->pszOwner  = NULL;
+        pEntry->pszGroup  = NULL;
+        pEntry->cchName   = cchEntry;
+        memcpy(pEntry->szName, pszEntry, cchEntry);
+        pEntry->szName[cchEntry] = '\0';
+
+        char *psz = &pEntry->szName[cchEntry + 1];
+        if (pszTarget)
+        {
+            pEntry->pszTarget = psz;
+            memcpy(psz, pszTarget, cbTarget);
+            psz += cbTarget;
+        }
+        if (pszOwner)
+        {
+            pEntry->pszOwner = psz;
+            memcpy(psz, pszOwner, cbOwner);
+            psz += cbOwner;
+        }
+        if (pszGroup)
+        {
+            pEntry->pszGroup = psz;
+            memcpy(psz, pszGroup, cbGroup);
+        }
+
+        pCollection->papEntries[pCollection->cEntries++] = pEntry;
+        pCollection->cbTotalAllocated += pEntry->Info.cbAllocated;
+        pCollection->cbTotalFiles     += pEntry->Info.cbObject;
+        return VINF_SUCCESS;
+    }
+    return VERR_NO_MEMORY;
+}
+
+/** @callback_method_impl{FNRTSORTCMP, Name} */
+static DECLCALLBACK(int) rtFtpServerCollEntryCmpName(void const *pvElement1, void const *pvElement2, void *pvUser)
+{
+    RT_NOREF(pvUser);
+    PRTFTPDIRENTRY pEntry1 = (PRTFTPDIRENTRY)pvElement1;
+    PRTFTPDIRENTRY pEntry2 = (PRTFTPDIRENTRY)pvElement2;
+    return RTStrCmp(pEntry1->szName, pEntry2->szName);
+}
+
+/** @callback_method_impl{FNRTSORTCMP, Dirs first + Name} */
+static DECLCALLBACK(int) rtFtpServerCollEntryCmpDirFirstName(void const *pvElement1, void const *pvElement2, void *pvUser)
+{
+    RT_NOREF(pvUser);
+    PRTFTPDIRENTRY pEntry1 = (PRTFTPDIRENTRY)pvElement1;
+    PRTFTPDIRENTRY pEntry2 = (PRTFTPDIRENTRY)pvElement2;
+    int iDiff = !RTFS_IS_DIRECTORY(pEntry1->Info.Attr.fMode) - !RTFS_IS_DIRECTORY(pEntry2->Info.Attr.fMode);
+    if (!iDiff)
+        iDiff = rtFtpServerCollEntryCmpName(pEntry1, pEntry2, pvUser);
+    return iDiff;
+}
+
+/**
+ * Sorts a given directory collection according to the FTP server's LIST style.
+ *
+ * @param   pCollection         Collection to sort.
+ */
+static void rtFtpServerCollSort(PRTFTPDIRCOLLECTION pCollection)
+{
+    PFNRTSORTCMP pfnCmp = rtFtpServerCollEntryCmpDirFirstName;
+    if (pfnCmp)
+        RTSortApvShell((void **)pCollection->papEntries, pCollection->cEntries, pfnCmp, NULL);
+}
+
+/**
+ * Writes a directory collection to a specific data connection.
+ *
+ * @returns VBox status code.
+ * @param   pDataConn           Data connection to write directory collection to.
+ * @param   pCollection         Collection to write.
+ * @param   pszTmp              Temporary buffer used for writing.
+ * @param   cbTmp               Size (in bytes) of temporary buffer used for writing.
+ */
+static int rtFtpServerDataConnDirCollWrite(PRTFTPSERVERDATACONN pDataConn, PRTFTPDIRCOLLECTION pCollection,
+                                           char *pszTmp, size_t cbTmp)
+{
+    size_t cchSizeCol  = 4;
+    size_t cchLinkCol  = 1;
+    size_t cchUidCol   = 1;
+    size_t cchGidCol   = 1;
+
+    size_t i = pCollection->cEntries;
+    while (i-- > 0)
+    {
+        PRTFTPDIRENTRY pEntry = pCollection->papEntries[i];
+
+        rtFtpServerFormatSize(pEntry->Info.cbObject, pszTmp, cbTmp);
+        size_t cchTmp = strlen(pszTmp);
+        if (cchTmp > cchSizeCol)
+            cchSizeCol = cchTmp;
+
+        cchTmp = rtFtpServerDecimalFormatLengthU32(pEntry->Info.Attr.u.Unix.cHardlinks) + 1;
+        if (cchTmp > cchLinkCol)
+            cchLinkCol = cchTmp;
+
+        rtFtpServerDecimalFormatOwner(pEntry->Info.Attr.u.Unix.uid, pEntry->pszOwner, pszTmp, cbTmp);
+        cchTmp = strlen(pszTmp);
+        if (cchTmp > cchUidCol)
+            cchUidCol = cchTmp;
+
+        rtFtpServerDecimalFormatGroup(pEntry->Info.Attr.u.Unix.gid, pEntry->pszGroup, pszTmp, cbTmp);
+        cchTmp = strlen(pszTmp);
+        if (cchTmp > cchGidCol)
+            cchGidCol = cchTmp;
+    }
+
+    size_t offTime = RT_UOFFSETOF(RTFTPDIRENTRY, Info.ModificationTime);
+
+    /*
+     * Display the entries.
+     */
+    for (i = 0; i < pCollection->cEntries; i++)
+    {
+        PRTFTPDIRENTRY pEntry = pCollection->papEntries[i];
+
+        RTFMODE fMode = pEntry->Info.Attr.fMode;
+        switch (fMode & RTFS_TYPE_MASK)
+        {
+            case RTFS_TYPE_FIFO:        rtFtpServerDataConnPrintf(pDataConn, "f"); break;
+            case RTFS_TYPE_DEV_CHAR:    rtFtpServerDataConnPrintf(pDataConn, "c"); break;
+            case RTFS_TYPE_DIRECTORY:   rtFtpServerDataConnPrintf(pDataConn, "d"); break;
+            case RTFS_TYPE_DEV_BLOCK:   rtFtpServerDataConnPrintf(pDataConn, "b"); break;
+            case RTFS_TYPE_FILE:        rtFtpServerDataConnPrintf(pDataConn, "-"); break;
+            case RTFS_TYPE_SYMLINK:     rtFtpServerDataConnPrintf(pDataConn, "l"); break;
+            case RTFS_TYPE_SOCKET:      rtFtpServerDataConnPrintf(pDataConn, "s"); break;
+            case RTFS_TYPE_WHITEOUT:    rtFtpServerDataConnPrintf(pDataConn, "w"); break;
+            default:                    rtFtpServerDataConnPrintf(pDataConn, "?"); AssertFailed(); break;
+        }
+
+        rtFtpServerDataConnPrintf(pDataConn, "%c%c%c",
+                                  fMode & RTFS_UNIX_IRUSR ? 'r' : '-',
+                                  fMode & RTFS_UNIX_IWUSR ? 'w' : '-',
+                                  fMode & RTFS_UNIX_IXUSR ? 'x' : '-');
+        rtFtpServerDataConnPrintf(pDataConn, "%c%c%c",
+                                  fMode & RTFS_UNIX_IRGRP ? 'r' : '-',
+                                  fMode & RTFS_UNIX_IWGRP ? 'w' : '-',
+                                  fMode & RTFS_UNIX_IXGRP ? 'x' : '-');
+        rtFtpServerDataConnPrintf(pDataConn, "%c%c%c",
+                                  fMode & RTFS_UNIX_IROTH ? 'r' : '-',
+                                  fMode & RTFS_UNIX_IWOTH ? 'w' : '-',
+                                  fMode & RTFS_UNIX_IXOTH ? 'x' : '-');
+
+        rtFtpServerDataConnPrintf(pDataConn, " %*u",
+                                  cchLinkCol, pEntry->Info.Attr.u.Unix.cHardlinks);
+
+        if (cchUidCol)
+            rtFtpServerDataConnPrintf(pDataConn, " %*s", cchUidCol,
+                                      rtFtpServerDecimalFormatOwner(pEntry->Info.Attr.u.Unix.uid, pEntry->pszOwner, pszTmp, cbTmp));
+        if (cchGidCol)
+            rtFtpServerDataConnPrintf(pDataConn, " %*s", cchGidCol,
+                                      rtFtpServerDecimalFormatGroup(pEntry->Info.Attr.u.Unix.gid, pEntry->pszGroup, pszTmp, cbTmp));
+
+        rtFtpServerDataConnPrintf(pDataConn, "%*s", cchSizeCol, rtFtpServerFormatSize(pEntry->Info.cbObject, pszTmp, cbTmp));
+
+        PCRTTIMESPEC pTime = (PCRTTIMESPEC)((uintptr_t)pEntry + offTime);
+        rtFtpServerDataConnPrintf(pDataConn," %s", rtFtpServerFormatTimestamp(pTime, pszTmp, cbTmp));
+
+        rtFtpServerDataConnPrintf(pDataConn," %s\r\n", rtFtpServerFormatName(pEntry->szName, pszTmp, cbTmp));
+    }
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Thread for handling the LIST command's output in a separate data connection.
+ *
+ * @returns VBox status code.
+ * @param   ThreadSelf          Thread handle. Unused.
+ * @param   pvUser              User-provided arguments. Of type PRTFTPSERVERCLIENT.
+ */
+static DECLCALLBACK(int) rtFtpServerDataConnListThread(RTTHREAD ThreadSelf, void *pvUser)
+{
+    RT_NOREF(ThreadSelf);
+
+    PRTFTPSERVERCLIENT pClient = (PRTFTPSERVERCLIENT)pvUser;
+    AssertPtr(pClient);
+
+    PRTFTPSERVERDATACONN pDataConn = pClient->pDataConn;
+    AssertPtr(pDataConn);
+
+    LogFlowFuncEnter();
+
+    int rc;
+
+    char szTmp[RTPATH_MAX * 2];
+    PRTFTPDIRCOLLECTION pColl = rtFtpServerDataConnDirCollAlloc();
+    AssertPtrReturn(pColl, VERR_NO_MEMORY);
+
+    /* Set start indicator. */
+    pDataConn->fStarted = true;
+
+    RTThreadUserSignal(RTThreadSelf());
+
+    /* The first argument might indicate a directory to list.
+     * If no argument is given, the implementation must use the last directory set. */
+    char *pszPath = RTStrDup(  pDataConn->cArgs == 1
+                             ? pDataConn->papszArgs[0] : pDataConn->pClient->State.pszCWD); /** @todo Needs locking. */
+    AssertPtrReturn(pszPath, VERR_NO_MEMORY);
+    /* The paths already have been validated in the actual command handlers. */
+
+    void *pvHandle = NULL; /* Shut up MSVC. */
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnDirOpen, pszPath, &pvHandle);
+
+    for (;;)
+    {
+        RTFSOBJINFO objInfo;
+        RT_ZERO(objInfo);
+
+        char *pszEntry  = NULL;
+        char *pszOwner  = NULL;
+        char *pszGroup  = NULL;
+        char *pszTarget = NULL;
+
+        RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnDirRead, pvHandle, &pszEntry,
+                                       &objInfo, &pszOwner, &pszGroup, &pszTarget);
+        if (RT_SUCCESS(rc))
+        {
+            int rc2 = rtFtpServerDataConnDirCollAddEntry(pColl, pszEntry,
+                                                         &objInfo, pszOwner, pszGroup, pszTarget);
+
+            RTStrFree(pszEntry);
+            pszEntry = NULL;
+
+            RTStrFree(pszOwner);
+            pszOwner = NULL;
+
+            RTStrFree(pszGroup);
+            pszGroup = NULL;
+
+            RTStrFree(pszTarget);
+            pszTarget = NULL;
+
+            if (RT_SUCCESS(rc))
+                rc = rc2;
+        }
+        else
+        {
+            if (rc == VERR_NO_MORE_FILES)
+            {
+                rc = VINF_SUCCESS;
+                break;
+            }
+        }
+
+        if (RT_FAILURE(rc))
+            break;
+
+        if (ASMAtomicReadBool(&pDataConn->fStop))
+            break;
+    }
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnDirClose, pvHandle);
+    pvHandle = NULL;
+
+    rtFtpServerCollSort(pColl);
+
+    if (RT_SUCCESS(rc))
+    {
+        int rc2 = rtFtpServerDataConnDirCollWrite(pDataConn, pColl, szTmp, sizeof(szTmp));
+        AssertRC(rc2);
+    }
+
+    rtFtpServerDataConnDirCollFree(pColl);
+
+    RTStrFree(pszPath);
+
+    pDataConn->fStopped = true;
+    pDataConn->rc       = rc;
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleLIST(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    /* If no argument is given, use the server's CWD as the path. */
+    const char *pszPath = cArgs ? apszArgs[0] : pClient->State.pszCWD;
+    AssertPtr(pszPath);
+
+    int rc = VINF_SUCCESS;
+
+    if (!rtFtpServerPathIsValid(pszPath, false /* fIsAbsolute */))
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+        AssertRC(rc2);
+    }
+    else
+    {
+        RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileStat, pszPath, NULL /* PRTFSOBJINFO */);
+
+        if (RT_SUCCESS(rc))
+        {
+            if (pClient->pDataConn == NULL)
+            {
+                rc = rtFtpServerDataConnCreate(pClient, &pClient->pDataConn);
+                if (RT_SUCCESS(rc))
+                    rc = rtFtpServerDataConnStart(pClient->pDataConn, rtFtpServerDataConnListThread, cArgs, apszArgs);
+
+                int rc2 = rtFtpServerSendReplyRc(  pClient, RT_SUCCESS(rc)
+                                                 ? RTFTPSERVER_REPLY_DATACONN_ALREADY_OPEN
+                                                 : RTFTPSERVER_REPLY_CANT_OPEN_DATA_CONN);
+                AssertRC(rc2);
+            }
+            else
+            {
+                 int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_DATACONN_ALREADY_OPEN);
+                 AssertRC(rc2);
+            }
+        }
+        else
+        {
+            int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+            AssertRC(rc2);
+        }
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleMODE(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(pClient, cArgs, apszArgs);
+
+    /** @todo Anything to do here? */
+    return VINF_SUCCESS;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleNOOP(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    /* Save timestamp of last command sent. */
+    pClient->State.tsLastCmdMs = RTTimeMilliTS();
+
+    return rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+}
+
+static DECLCALLBACK(int) rtFtpServerHandlePASS(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_ERROR_INVALID_PARAMETERS);
+
+    const char *pszPassword = apszArgs[0];
+    AssertPtrReturn(pszPassword, VERR_INVALID_PARAMETER);
+
+    int rc = rtFtpServerAuthenticate(pClient, pClient->State.pszUser, pszPassword);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_LOGGED_IN_PROCEED);
+    }
+    else
+    {
+        pClient->State.cFailedLoginAttempts++;
+
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_NOT_LOGGED_IN);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandlePORT(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_ERROR_INVALID_PARAMETERS);
+
+    RTFTPSERVER_REPLY rcClient;
+
+    int rc = rtFtpParseHostAndPort(apszArgs[0], &pClient->DataConnAddr, &pClient->uDataConnPort);
+    if (RT_SUCCESS(rc))
+        rcClient = RTFTPSERVER_REPLY_OKAY;
+    else
+        rcClient = RTFTPSERVER_REPLY_ERROR_INVALID_PARAMETERS;
+
+    int rc2 = rtFtpServerSendReplyRc(pClient, rcClient);
+    if (RT_SUCCESS(rc))
+        rc = rc2;
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandlePWD(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc;
+
+    char szPWD[RTPATH_MAX];
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnPathGetCurrent, szPWD, sizeof(szPWD));
+
+    if (RT_SUCCESS(rc))
+       rc = rtFtpServerSendReplyRcEx(pClient, RTFTPSERVER_REPLY_PATHNAME_OK, "\"%s\"", szPWD); /* See RFC 959, APPENDIX II. */
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleOPTS(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc = VINF_SUCCESS;
+
+    int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+    if (RT_SUCCESS(rc))
+        rc = rc2;
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleQUIT(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    int rc = VINF_SUCCESS;
+
+    if (pClient->pDataConn)
+    {
+        rc = rtFtpServerDataConnClose(pClient->pDataConn);
+        if (RT_SUCCESS(rc))
+        {
+            rtFtpServerDataConnDestroy(pClient->pDataConn);
+            pClient->pDataConn = NULL;
+        }
+    }
+
+    int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+    if (RT_SUCCESS(rc))
+        rc = rc2;
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleRETR(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1) /* File name needs to be present. */
+        return VERR_INVALID_PARAMETER;
+
+    int rc;
+
+    const char *pszPath = apszArgs[0];
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileStat, pszPath, NULL /* PRTFSOBJINFO */);
+
+    if (RT_SUCCESS(rc))
+    {
+        if (RT_SUCCESS(rc))
+        {
+            if (pClient->pDataConn == NULL)
+            {
+                rc = rtFtpServerDataConnCreate(pClient, &pClient->pDataConn);
+                if (RT_SUCCESS(rc))
+                    rc = rtFtpServerDataConnStart(pClient->pDataConn, rtFtpServerDataConnFileWriteThread, cArgs, apszArgs);
+
+                int rc2 = rtFtpServerSendReplyRc(  pClient, RT_SUCCESS(rc)
+                                                 ? RTFTPSERVER_REPLY_DATACONN_ALREADY_OPEN
+                                                 : RTFTPSERVER_REPLY_CANT_OPEN_DATA_CONN);
+                AssertRC(rc2);
+            }
+            else
+            {
+                 int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_DATACONN_ALREADY_OPEN);
+                 AssertRC(rc2);
+            }
+        }
+        else
+        {
+            int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+            AssertRC(rc2);
+        }
+    }
+
+    if (RT_FAILURE(rc))
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_REQ_ACTION_NOT_TAKEN);
+        AssertRC(rc2);
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleSIZE(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    int rc;
+
+    const char *pszPath = apszArgs[0];
+    uint64_t uSize = 0;
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileGetSize, pszPath, &uSize);
+
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtFtpServerSendReplyStr(pClient, "213 %RU64\r\n", uSize);
+    }
+    else
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_REQ_ACTION_NOT_TAKEN);
+        AssertRC(rc2);
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleSTAT(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    int rc;
+
+    RTFSOBJINFO objInfo;
+    RT_ZERO(objInfo);
+
+    const char *pszPath = apszArgs[0];
+
+    RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnFileStat, pszPath, &objInfo);
+
+    if (RT_SUCCESS(rc))
+    {
+        char szFsObjInfo[_4K]; /** @todo Check this size. */
+        rc = rtFtpServerFsObjInfoToStr(&objInfo, szFsObjInfo, sizeof(szFsObjInfo));
+        if (RT_SUCCESS(rc))
+        {
+            char szFsPathInfo[RTPATH_MAX + 16];
+            const ssize_t cchPathInfo = RTStrPrintf2(szFsPathInfo, sizeof(szFsPathInfo), " %2zu %s\n", strlen(pszPath), pszPath);
+            if (cchPathInfo > 0)
+            {
+                rc = RTStrCat(szFsObjInfo, sizeof(szFsObjInfo), szFsPathInfo);
+                if (RT_SUCCESS(rc))
+                    rc = rtFtpServerSendReplyStr(pClient, szFsObjInfo);
+            }
+            else
+                rc = VERR_BUFFER_OVERFLOW;
+        }
+    }
+
+    if (RT_FAILURE(rc))
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_REQ_ACTION_NOT_TAKEN);
+        AssertRC(rc2);
+    }
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleSTRU(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    const char *pszType = apszArgs[0];
+
+    int rc;
+
+    if (!RTStrICmp(pszType, "F"))
+    {
+        pClient->State.enmStructType = RTFTPSERVER_STRUCT_TYPE_FILE;
+
+        rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+    }
+    else
+        rc = VERR_NOT_IMPLEMENTED;
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleSYST(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    RT_NOREF(cArgs, apszArgs);
+
+    char szOSInfo[64];
+    int rc = RTSystemQueryOSInfo(RTSYSOSINFO_PRODUCT, szOSInfo, sizeof(szOSInfo));
+    if (RT_SUCCESS(rc))
+        rc = rtFtpServerSendReplyStr(pClient, "215 %s", szOSInfo);
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleTYPE(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    const char *pszType = apszArgs[0];
+
+    int rc = VINF_SUCCESS;
+
+    if (!RTStrICmp(pszType, "A"))
+    {
+        pClient->State.enmDataType = RTFTPSERVER_DATA_TYPE_ASCII;
+    }
+    else if (!RTStrICmp(pszType, "I")) /* Image (binary). */
+    {
+        pClient->State.enmDataType = RTFTPSERVER_DATA_TYPE_IMAGE;
+    }
+    else /** @todo Support "E" (EBCDIC) and/or "L <size>" (custom)? */
+        rc = VERR_NOT_IMPLEMENTED;
+
+    if (RT_SUCCESS(rc))
+        rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_OKAY);
+
+    return rc;
+}
+
+static DECLCALLBACK(int) rtFtpServerHandleUSER(PRTFTPSERVERCLIENT pClient, uint8_t cArgs, const char * const *apszArgs)
+{
+    if (cArgs != 1)
+        return VERR_INVALID_PARAMETER;
+
+    const char *pszUser = apszArgs[0];
+    AssertPtrReturn(pszUser, VERR_INVALID_PARAMETER);
+
+    rtFtpServerClientStateReset(&pClient->State);
+
+    int rc = rtFtpServerLookupUser(pClient, pszUser);
+    if (RT_SUCCESS(rc))
+    {
+        pClient->State.pszUser = RTStrDup(pszUser);
+        AssertPtrReturn(pClient->State.pszUser, VERR_NO_MEMORY);
+
+        rc = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_USERNAME_OKAY_NEED_PASSWORD);
+    }
+    else
+    {
+        pClient->State.cFailedLoginAttempts++;
+
+        int rc2 = rtFtpServerSendReplyRc(pClient, RTFTPSERVER_REPLY_NOT_LOGGED_IN);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
+
+    return rc;
+}
+
+
+/*********************************************************************************************************************************
+*   Internal server functions                                                                                                    *
+*********************************************************************************************************************************/
+
+/**
+ * Parses FTP command arguments handed in by the client.
+ *
+ * @returns VBox status code.
+ * @param   pszCmdParms         Pointer to command arguments, if any. Can be NULL if no arguments are given.
+ * @param   pcArgs              Returns the number of parsed arguments, separated by a space (hex 0x20).
+ * @param   ppapszArgs          Returns the string array of parsed arguments. Needs to be free'd with rtFtpServerCmdArgsFree().
+ */
+static int rtFtpServerCmdArgsParse(const char *pszCmdParms, uint8_t *pcArgs, char ***ppapszArgs)
+{
+    *pcArgs      = 0;
+    *ppapszArgs = NULL;
+
+    if (!pszCmdParms) /* No parms given? Bail out early. */
+        return VINF_SUCCESS;
+
+    /** @todo Anything else to do here? */
+    /** @todo Check if quoting is correct. */
+
+    int cArgs = 0;
+    int rc = RTGetOptArgvFromString(ppapszArgs, &cArgs, pszCmdParms, RTGETOPTARGV_CNV_QUOTE_MS_CRT, " " /* Separators */);
+    if (RT_SUCCESS(rc))
+    {
+        if (cArgs <= UINT8_MAX)
+        {
+            *pcArgs = (uint8_t)cArgs;
+        }
+        else
+            rc = VERR_INVALID_PARAMETER;
+    }
+
+    return rc;
+}
+
+/**
+ * Frees a formerly argument string array parsed by rtFtpServerCmdArgsParse().
+ *
+ * @param   ppapszArgs          Argument string array to free.
+ */
+static void rtFtpServerCmdArgsFree(char **ppapszArgs)
+{
+    RTGetOptArgvFree(ppapszArgs);
+}
+
+/**
+ * Main function for processing client commands for the control connection.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to process commands for.
+ * @param   pszCmd              Command string to parse and handle.
+ * @param   cbCmd               Size (in bytes) of command string.
+ */
+static int rtFtpServerProcessCommands(PRTFTPSERVERCLIENT pClient, char *pszCmd, size_t cbCmd)
+{
+    /* Make sure to terminate the string in any case. */
+    pszCmd[RT_MIN(RTFTPSERVER_MAX_CMD_LEN, cbCmd)] = '\0';
+
+    /* A tiny bit of sanitation. */
+    RTStrStripL(pszCmd);
+
+    /* First, terminate string by finding the command end marker (telnet style). */
+    /** @todo Not sure if this is entirely correct and/or needs tweaking; good enough for now as it seems. */
+    char *pszCmdEnd = RTStrStr(pszCmd, "\r\n");
+    if (pszCmdEnd)
+        *pszCmdEnd = '\0';
+
+    /* Reply which gets sent back to the client. */
+    RTFTPSERVER_REPLY rcClient = RTFTPSERVER_REPLY_INVALID;
+
+    int rcCmd = VINF_SUCCESS;
+
+    uint8_t cArgs     = 0;
+    char  **papszArgs = NULL;
+    int rc = rtFtpServerCmdArgsParse(pszCmd, &cArgs, &papszArgs);
+    if (   RT_SUCCESS(rc)
+        && cArgs) /* At least the actual command (without args) must be present. */
+    {
+        LogFlowFunc(("Handling command '%s'\n", papszArgs[0]));
+        for (uint8_t a = 0; a < cArgs; a++)
+            LogFlowFunc(("\targ[%RU8] = '%s'\n", a, papszArgs[a]));
+
+        unsigned i = 0;
+        for (; i < RT_ELEMENTS(g_aCmdMap); i++)
+        {
+            const RTFTPSERVERCMD_ENTRY *pCmdEntry = &g_aCmdMap[i];
+
+            if (!RTStrICmp(papszArgs[0], pCmdEntry->szCmd))
+            {
+                /* Some commands need a valid user before they can be executed. */
+                if (   pCmdEntry->fNeedsUser
+                    && pClient->State.pszUser == NULL)
+                {
+                    rcClient = RTFTPSERVER_REPLY_NOT_LOGGED_IN;
+                    break;
+                }
+
+                /* Save timestamp of last command sent. */
+                pClient->State.tsLastCmdMs = RTTimeMilliTS();
+
+                /* Hand in arguments only without the actual command. */
+                rcCmd = pCmdEntry->pfnCmd(pClient, cArgs - 1, cArgs > 1 ? &papszArgs[1] : NULL);
+                if (RT_FAILURE(rcCmd))
+                {
+                    LogFunc(("Handling command '%s' failed with %Rrc\n", papszArgs[0], rcCmd));
+
+                    switch (rcCmd)
+                    {
+                        case VERR_INVALID_PARAMETER:
+                            RT_FALL_THROUGH();
+                        case VERR_INVALID_POINTER:
+                            rcClient = RTFTPSERVER_REPLY_ERROR_INVALID_PARAMETERS;
+                            break;
+
+                        case VERR_NOT_IMPLEMENTED:
+                            rcClient = RTFTPSERVER_REPLY_ERROR_CMD_NOT_IMPL;
+                            break;
+
+                        default:
+                            break;
+                    }
+                }
+                break;
+            }
+        }
+
+        rtFtpServerCmdArgsFree(papszArgs);
+
+        if (i == RT_ELEMENTS(g_aCmdMap))
+        {
+            LogFlowFunc(("Command not implemented\n"));
+            Assert(rcClient == RTFTPSERVER_REPLY_INVALID);
+            rcClient = RTFTPSERVER_REPLY_ERROR_CMD_NOT_IMPL;
+        }
+
+        const bool fDisconnect =    g_aCmdMap[i].enmCmd == RTFTPSERVERCMD_QUIT
+                                 || pClient->State.cFailedLoginAttempts >= 3; /** @todo Make this dynamic. */
+        if (fDisconnect)
+        {
+            RTFTPSERVER_HANDLE_CALLBACK_VA(pfnOnUserDisconnect, pClient->State.pszUser);
+
+            rtFtpServerClientStateReset(&pClient->State);
+
+            Assert(rcClient == RTFTPSERVER_REPLY_INVALID);
+            rcClient = RTFTPSERVER_REPLY_CLOSING_CTRL_CONN;
+        }
+    }
+    else
+        rcClient = RTFTPSERVER_REPLY_ERROR_INVALID_PARAMETERS;
+
+    if (rcClient != RTFTPSERVER_REPLY_INVALID)
+    {
+        int rc2 = rtFtpServerSendReplyRc(pClient, rcClient);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Main loop for processing client commands.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to process commands for.
+ */
+static int rtFtpServerClientMain(PRTFTPSERVERCLIENT pClient)
+{
+    int rc;
+
+    size_t cbRead;
+    char   szCmd[RTFTPSERVER_MAX_CMD_LEN + 1];
+
+    for (;;)
+    {
+        rc = RTTcpSelectOne(pClient->hSocket, 200 /* ms */); /** @todo Can we improve here? Using some poll events or so? */
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTTcpReadNB(pClient->hSocket, szCmd, sizeof(szCmd), &cbRead);
+            if (   RT_SUCCESS(rc)
+                && cbRead)
+            {
+                AssertBreakStmt(cbRead <= sizeof(szCmd), rc = VERR_BUFFER_OVERFLOW);
+                rc = rtFtpServerProcessCommands(pClient, szCmd, cbRead);
+            }
+        }
+        else if (rc == VERR_TIMEOUT)
+            rc = VINF_SUCCESS;
+        else
+            break;
+
+        /*
+         * Handle data connection replies.
+         */
+        if (pClient->pDataConn)
+        {
+            if (   ASMAtomicReadBool(&pClient->pDataConn->fStarted)
+                && ASMAtomicReadBool(&pClient->pDataConn->fStopped))
+            {
+                Assert(pClient->pDataConn->rc != VERR_IPE_UNINITIALIZED_STATUS);
+
+                int rc2 = rtFtpServerSendReplyRc(pClient,
+                                                   RT_SUCCESS(pClient->pDataConn->rc)
+                                                 ? RTFTPSERVER_REPLY_CLOSING_DATA_CONN : RTFTPSERVER_REPLY_CONN_REQ_FILE_ACTION_NOT_TAKEN);
+                AssertRC(rc2);
+
+                rc = rtFtpServerDataConnStop(pClient->pDataConn);
+                if (RT_SUCCESS(rc))
+                {
+                    rtFtpServerDataConnDestroy(pClient->pDataConn);
+                    pClient->pDataConn = NULL;
+                }
+            }
+        }
+    }
+
+    /* Make sure to destroy all data connections. */
+    rtFtpServerDataConnDestroy(pClient->pDataConn);
+    pClient->pDataConn = NULL;
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Resets the client's state.
+ *
+ * @param   pState              Client state to reset.
+ */
+static void rtFtpServerClientStateReset(PRTFTPSERVERCLIENTSTATE pState)
+{
+    LogFlowFuncEnter();
+
+    RTStrFree(pState->pszUser);
+    pState->pszUser = NULL;
+
+    int rc2 = rtFtpSetCWD(pState, "/");
+    AssertRC(rc2);
+
+    pState->cFailedLoginAttempts = 0;
+    pState->tsLastCmdMs          = RTTimeMilliTS();
+    pState->enmDataType          = RTFTPSERVER_DATA_TYPE_ASCII;
+    pState->enmStructType        = RTFTPSERVER_STRUCT_TYPE_FILE;
+}
+
+/**
+ * Per-client thread for serving the server's control connection.
+ *
+ * @returns VBox status code.
+ * @param   hSocket             Socket handle to use for the control connection.
+ * @param   pvUser              User-provided arguments. Of type PRTFTPSERVERINTERNAL.
+ */
+static DECLCALLBACK(int) rtFtpServerClientThread(RTSOCKET hSocket, void *pvUser)
+{
+    PRTFTPSERVERINTERNAL pThis = (PRTFTPSERVERINTERNAL)pvUser;
+    RTFTPSERVER_VALID_RETURN(pThis);
+
+    RTFTPSERVERCLIENT Client;
+    RT_ZERO(Client);
+
+    Client.pServer     = pThis;
+    Client.hSocket     = hSocket;
+
+    LogFlowFunc(("New client connected\n"));
+
+    rtFtpServerClientStateReset(&Client.State);
+
+    /*
+     * Send welcome message.
+     * Note: Some clients (like FileZilla / Firefox) expect a message together with the reply code,
+     *       so make sure to include at least *something*.
+     */
+    int rc = rtFtpServerSendReplyRcEx(&Client, RTFTPSERVER_REPLY_READY_FOR_NEW_USER,
+                                     "Welcome!");
+    if (RT_SUCCESS(rc))
+    {
+        ASMAtomicIncU32(&pThis->cClients);
+
+        rc = rtFtpServerClientMain(&Client);
+
+        ASMAtomicDecU32(&pThis->cClients);
+    }
+
+    rtFtpServerClientStateReset(&Client.State);
+
+    return rc;
+}
+
+RTR3DECL(int) RTFtpServerCreate(PRTFTPSERVER phFTPServer, const char *pszAddress, uint16_t uPort,
+                                PRTFTPSERVERCALLBACKS pCallbacks, void *pvUser, size_t cbUser)
+{
+    AssertPtrReturn(phFTPServer,  VERR_INVALID_POINTER);
+    AssertPtrReturn(pszAddress,  VERR_INVALID_POINTER);
+    AssertReturn   (uPort,        VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pCallbacks,   VERR_INVALID_POINTER);
+    /* pvUser is optional. */
+
+    int rc;
+
+    PRTFTPSERVERINTERNAL pThis = (PRTFTPSERVERINTERNAL)RTMemAllocZ(sizeof(RTFTPSERVERINTERNAL));
+    if (pThis)
+    {
+        pThis->u32Magic  = RTFTPSERVER_MAGIC;
+        pThis->Callbacks = *pCallbacks;
+        pThis->pvUser    = pvUser;
+        pThis->cbUser    = cbUser;
+
+        rc = RTTcpServerCreate(pszAddress, uPort, RTTHREADTYPE_DEFAULT, "ftpsrv",
+                               rtFtpServerClientThread, pThis /* pvUser */, &pThis->pTCPServer);
+        if (RT_SUCCESS(rc))
+        {
+            *phFTPServer = (RTFTPSERVER)pThis;
+        }
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+RTR3DECL(int) RTFtpServerDestroy(RTFTPSERVER hFTPServer)
+{
+    if (hFTPServer == NIL_RTFTPSERVER)
+        return VINF_SUCCESS;
+
+    PRTFTPSERVERINTERNAL pThis = hFTPServer;
+    RTFTPSERVER_VALID_RETURN(pThis);
+
+    AssertPtr(pThis->pTCPServer);
+
+    int rc = RTTcpServerDestroy(pThis->pTCPServer);
+    if (RT_SUCCESS(rc))
+    {
+        pThis->u32Magic = RTFTPSERVER_MAGIC_DEAD;
+
+        RTMemFree(pThis);
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/generic/Makefile.kup b/src/VBox/Runtime/r3/generic/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/Makefile.kup
diff --git a/src/VBox/Runtime/r3/generic/RTLocaleQueryLocaleName-r3-generic.cpp b/src/VBox/Runtime/r3/generic/RTLocaleQueryLocaleName-r3-generic.cpp
new file mode 100644
index 00000000..1618d593
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/RTLocaleQueryLocaleName-r3-generic.cpp
@@ -0,0 +1,67 @@
+/* $Id: RTLocaleQueryLocaleName-r3-generic.cpp $ */
+/** @file
+ * IPRT - RTLocaleQueryLocaleName, ring-3 generic.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <locale.h>
+
+#include <iprt/locale.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#ifdef RT_OS_SOLARIS
+#include <iprt/path.h>
+#endif /* RT_OS_SOLARIS */
+
+
+
+RTDECL(int) RTLocaleQueryLocaleName(char *pszName, size_t cbName)
+{
+    const char *pszLocale = setlocale(LC_ALL, NULL);
+    if (pszLocale)
+    {
+#ifdef RT_OS_SOLARIS /* Solaris can return a locale starting with a slash ('/'), e.g. /en_GB.UTF-8/C/C/C/C/C */
+        if (RTPATH_IS_SLASH(*pszLocale))
+            pszLocale++;
+#endif /* RT_OS_SOLARIS */
+        return RTStrCopy(pszName, cbName, pszLocale);
+    }
+    return VERR_NOT_AVAILABLE;
+}
+
diff --git a/src/VBox/Runtime/r3/generic/RTLocaleQueryNormalizedBaseLocaleName-r3-generic.cpp b/src/VBox/Runtime/r3/generic/RTLocaleQueryNormalizedBaseLocaleName-r3-generic.cpp
new file mode 100644
index 00000000..6ae8ef83
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/RTLocaleQueryNormalizedBaseLocaleName-r3-generic.cpp
@@ -0,0 +1,102 @@
+/* $Id: RTLocaleQueryNormalizedBaseLocaleName-r3-generic.cpp $ */
+/** @file
+ * IPRT - RTLocaleQueryNormalizedBaseLocaleName, ring-3 generic.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/locale.h>
+#include "internal/iprt.h"
+
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+
+/*
+ * Note! Code duplicated in r3/win/RTLocaleQueryNormalizedBaseLocaleName-win.cpp (adds fallback).
+ */
+RTDECL(int) RTLocaleQueryNormalizedBaseLocaleName(char *pszName, size_t cbName)
+{
+    char szLocale[_1K];
+    int rc = RTLocaleQueryLocaleName(szLocale, sizeof(szLocale));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * May return some complicated "LC_XXX=yyy;LC.." sequence if
+         * partially set (like IPRT does).  Try get xx_YY sequence first
+         * because 'C' or 'POSIX' may be LC_xxx variants that haven't been
+         * set yet.
+         *
+         * ASSUMES complicated locale mangling is done in a certain way...
+         */
+        const char *pszLocale = strchr(szLocale, '=');
+        if (!pszLocale)
+            pszLocale = szLocale;
+        else
+            pszLocale++;
+        bool fSeenC = false;
+        bool fSeenPOSIX = false;
+        do
+        {
+            const char *pszEnd = strchr(pszLocale, ';');
+
+            if (   RTLOCALE_IS_LANGUAGE2_UNDERSCORE_COUNTRY2(pszLocale)
+                && (   pszLocale[5] == '\0'
+                    || RT_C_IS_PUNCT(pszLocale[5])) )
+                return RTStrCopyEx(pszName, cbName, pszLocale, 5);
+
+            if (   pszLocale[0] == 'C'
+                && (   pszLocale[1] == '\0'
+                    || RT_C_IS_PUNCT(pszLocale[1])) )
+                fSeenC = true;
+            else if (   strncmp(pszLocale, "POSIX", 5) == 0
+                     && (   pszLocale[5] == '\0'
+                        || RT_C_IS_PUNCT(pszLocale[5])) )
+                fSeenPOSIX = true;
+
+            /* advance */
+            pszLocale = pszEnd ? strchr(pszEnd + 1, '=') : NULL;
+        } while (pszLocale++);
+
+        if (fSeenC || fSeenPOSIX)
+            return RTStrCopy(pszName, cbName, "C"); /* C and POSIX should be identical IIRC, so keep it simple. */
+
+        rc = VERR_NOT_AVAILABLE;
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/generic/RTLocaleQueryUserCountryCode-r3-generic.cpp b/src/VBox/Runtime/r3/generic/RTLocaleQueryUserCountryCode-r3-generic.cpp
new file mode 100644
index 00000000..64d675e2
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/RTLocaleQueryUserCountryCode-r3-generic.cpp
@@ -0,0 +1,87 @@
+/* $Id: RTLocaleQueryUserCountryCode-r3-generic.cpp $ */
+/** @file
+ * IPRT - RTLocaleQueryLocaleName, ring-3 generic.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <locale.h>
+
+#include <iprt/locale.h>
+#include "internal/iprt.h"
+
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+
+
+RTDECL(int) RTLocaleQueryUserCountryCode(char pszCountryCode[3])
+{
+    static const int s_aiLocales[] =
+    {
+        LC_ALL,
+        LC_CTYPE,
+        LC_COLLATE,
+        LC_MONETARY,
+        LC_NUMERIC,
+        LC_TIME
+    };
+
+    for (unsigned i = 0; i < RT_ELEMENTS(s_aiLocales); i++)
+    {
+        const char *pszLocale = setlocale(s_aiLocales[i], NULL);
+        if (   pszLocale
+            && strlen(pszLocale) >= 5
+            && RT_C_IS_ALPHA(pszLocale[0])
+            && RT_C_IS_ALPHA(pszLocale[1])
+            && pszLocale[2] == '_'
+            && RT_C_IS_ALPHA(pszLocale[3])
+            && RT_C_IS_ALPHA(pszLocale[4]))
+        {
+            pszCountryCode[0] = RT_C_TO_UPPER(pszLocale[3]);
+            pszCountryCode[1] = RT_C_TO_UPPER(pszLocale[4]);
+            pszCountryCode[2] = '\0';
+            return VINF_SUCCESS;
+        }
+    }
+
+    pszCountryCode[0] = 'Z';
+    pszCountryCode[1] = 'Z';
+    pszCountryCode[2] = '\0';
+    return VERR_NOT_AVAILABLE;
+}
+
diff --git a/src/VBox/Runtime/r3/generic/RTTimeZoneGetCurrent-generic.cpp b/src/VBox/Runtime/r3/generic/RTTimeZoneGetCurrent-generic.cpp
new file mode 100644
index 00000000..5cc6b39a
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/RTTimeZoneGetCurrent-generic.cpp
@@ -0,0 +1,51 @@
+/* $Id: RTTimeZoneGetCurrent-generic.cpp $ */
+/** @file
+ * IPRT - RTTimeZoneGetCurrent, generic.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/env.h>
+
+
+RTDECL(int) RTTimeZoneGetCurrent(char *pszName, size_t cbName)
+{
+    return RTEnvGetEx(RTENV_DEFAULT, "TZ", pszName, cbName, NULL);
+}
+
diff --git a/src/VBox/Runtime/r3/generic/allocex-r3-generic.cpp b/src/VBox/Runtime/r3/generic/allocex-r3-generic.cpp
new file mode 100644
index 00000000..2e7f0528
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/allocex-r3-generic.cpp
@@ -0,0 +1,70 @@
+/* $Id: allocex-r3-generic.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, Extended Alloc Workers, generic.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RTMEM_NO_WRAP_TO_EF_APIS
+#include <iprt/mem.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include "../allocex.h"
+
+
+
+DECLHIDDEN(int) rtMemAllocEx16BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    RT_NOREF(cbAlloc, fFlags, ppv);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+DECLHIDDEN(int) rtMemAllocEx32BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    RT_NOREF(cbAlloc, fFlags, ppv);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+DECLHIDDEN(void) rtMemFreeExYyBitReach(void *pv, size_t cb, uint32_t fFlags)
+{
+    RT_NOREF(pv, cb, fFlags);
+    AssertFailed();
+}
+
diff --git a/src/VBox/Runtime/r3/generic/dirrel-r3-generic.cpp b/src/VBox/Runtime/r3/generic/dirrel-r3-generic.cpp
new file mode 100644
index 00000000..da34638e
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/dirrel-r3-generic.cpp
@@ -0,0 +1,369 @@
+/* $Id: dirrel-r3-generic.cpp $ */
+/** @file
+ * IPRT - Directory relative base APIs, generic implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/dir.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/symlink.h>
+#define RTDIR_AGNOSTIC
+#include "internal/dir.h"
+
+
+
+/**
+ * Helper that builds a full path for a directory relative path.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The directory.
+ * @param   pszPathDst          The destination buffer.
+ * @param   cbPathDst           The size of the destination buffer.
+ * @param   pszRelPath          The relative path.
+ */
+static int rtDirRelBuildFullPath(PRTDIRINTERNAL pThis, char *pszPathDst, size_t cbPathDst, const char *pszRelPath)
+{
+    AssertMsgReturn(!RTPathStartsWithRoot(pszRelPath), ("pszRelPath='%s'\n", pszRelPath), VERR_PATH_IS_NOT_RELATIVE);
+
+    /*
+     * Let's hope we can avoid checking for ascension.
+     *
+     * Note! We don't take symbolic links into account here.  That can be
+     *       done later if desired.
+     */
+    if (   !(pThis->fFlags & RTDIR_F_DENY_ASCENT)
+        || strstr(pszRelPath, "..") == NULL)
+    {
+        size_t const cchRelPath = strlen(pszRelPath);
+        size_t const cchDirPath = pThis->cchPath;
+        if (cchDirPath + cchRelPath < cbPathDst)
+        {
+            memcpy(pszPathDst, pThis->pszPath, cchDirPath);
+            memcpy(&pszPathDst[cchDirPath], pszRelPath, cchRelPath);
+            pszPathDst[cchDirPath + cchRelPath] = '\0';
+            return VINF_SUCCESS;
+        }
+        return VERR_FILENAME_TOO_LONG;
+    }
+
+    /*
+     * Calc the absolute path using the directory as a base, then check if the result
+     * still starts with the full directory path.
+     *
+     * This ASSUMES that pThis->pszPath is an absolute path.
+     */
+    int rc = RTPathAbsEx(pThis->pszPath, pszRelPath, RTPATH_STR_F_STYLE_HOST, pszPathDst, &cbPathDst);
+    if (RT_SUCCESS(rc))
+    {
+        if (RTPathStartsWith(pszPathDst, pThis->pszPath))
+            return VINF_SUCCESS;
+        return VERR_PATH_NOT_FOUND;
+    }
+    return rc;
+}
+
+
+/*
+ *
+ *
+ * RTFile stuff.
+ * RTFile stuff.
+ * RTFile stuff.
+ *
+ *
+ */
+
+
+
+
+RTDECL(int)  RTDirRelFileOpen(RTDIR hDir, const char *pszRelFilename, uint64_t fOpen, PRTFILE phFile)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelFilename);
+    if (RT_SUCCESS(rc))
+        rc = RTFileOpen(phFile, szPath, fOpen);
+    return rc;
+}
+
+
+
+/*
+ *
+ *
+ * RTDir stuff.
+ * RTDir stuff.
+ * RTDir stuff.
+ *
+ *
+ */
+
+
+
+RTDECL(int) RTDirRelDirOpen(RTDIR hDir, const char *pszDir, RTDIR *phDir)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszDir);
+    if (RT_SUCCESS(rc))
+        rc = RTDirOpen(phDir, szPath);
+    return rc;
+
+}
+
+
+RTDECL(int) RTDirRelDirOpenFiltered(RTDIR hDir, const char *pszDirAndFilter, RTDIRFILTER enmFilter,
+                                    uint32_t fFlags, RTDIR *phDir)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszDirAndFilter);
+    if (RT_SUCCESS(rc))
+        rc = RTDirOpenFiltered(phDir, szPath, enmFilter, fFlags);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelDirCreate(RTDIR hDir, const char *pszRelPath, RTFMODE fMode, uint32_t fCreate, RTDIR *phSubDir)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTDirCreate(szPath, fMode, fCreate);
+        if (RT_SUCCESS(rc) && phSubDir)
+            rc = RTDirOpen(phSubDir, szPath);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelDirRemove(RTDIR hDir, const char *pszRelPath)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTDirRemove(szPath);
+    return rc;
+}
+
+
+/*
+ *
+ * RTPath stuff.
+ * RTPath stuff.
+ * RTPath stuff.
+ *
+ *
+ */
+
+
+RTDECL(int) RTDirRelPathQueryInfo(RTDIR hDir, const char *pszRelPath, PRTFSOBJINFO pObjInfo,
+                                  RTFSOBJATTRADD enmAddAttr, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTPathQueryInfoEx(szPath, pObjInfo, enmAddAttr, fFlags);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetMode(RTDIR hDir, const char *pszRelPath, RTFMODE fMode, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_FLAGS);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+    {
+#ifndef RT_OS_WINDOWS
+        rc = RTPathSetMode(szPath, fMode); /** @todo fFlags is currently ignored. */
+#else
+        rc = VERR_NOT_IMPLEMENTED; /** @todo implement RTPathSetMode on windows. */
+        RT_NOREF(fMode);
+#endif
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetTimes(RTDIR hDir, const char *pszRelPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                                 PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTPathSetTimesEx(szPath, pAccessTime, pModificationTime, pChangeTime, pBirthTime, fFlags);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetOwner(RTDIR hDir, const char *pszRelPath, uint32_t uid, uint32_t gid, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+    {
+#ifndef RT_OS_WINDOWS
+        rc = RTPathSetOwnerEx(szPath, uid, gid, fFlags);
+#else
+        rc = VERR_NOT_IMPLEMENTED;
+        RT_NOREF(uid, gid, fFlags);
+#endif
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathRename(RTDIR hDirSrc, const char *pszSrc, RTDIR hDirDst, const char *pszDst, unsigned fRename)
+{
+    PRTDIRINTERNAL pThis = hDirSrc;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    PRTDIRINTERNAL pThat = hDirDst;
+    if (pThat != pThis)
+    {
+        AssertPtrReturn(pThat, VERR_INVALID_HANDLE);
+        AssertReturn(pThat->u32Magic != RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    }
+
+    char szSrcPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szSrcPath, sizeof(szSrcPath), pszSrc);
+    if (RT_SUCCESS(rc))
+    {
+        char szDstPath[RTPATH_MAX];
+        rc = rtDirRelBuildFullPath(pThis, szDstPath, sizeof(szDstPath), pszDst);
+        if (RT_SUCCESS(rc))
+            rc = RTPathRename(szSrcPath, szDstPath, fRename);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathUnlink(RTDIR hDir, const char *pszRelPath, uint32_t fUnlink)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTPathUnlink(szPath, fUnlink);
+    return rc;
+}
+
+
+/*
+ *
+ * RTSymlink stuff.
+ * RTSymlink stuff.
+ * RTSymlink stuff.
+ *
+ *
+ */
+
+
+RTDECL(int) RTDirRelSymlinkCreate(RTDIR hDir, const char *pszSymlink, const char *pszTarget,
+                                  RTSYMLINKTYPE enmType, uint32_t fCreate)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszSymlink);
+    if (RT_SUCCESS(rc))
+        rc = RTSymlinkCreate(szPath, pszTarget, enmType, fCreate);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelSymlinkRead(RTDIR hDir, const char *pszSymlink, char *pszTarget, size_t cbTarget, uint32_t fRead)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszSymlink);
+    if (RT_SUCCESS(rc))
+        rc = RTSymlinkRead(szPath, pszTarget, cbTarget, fRead);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/generic/semspinmutex-r3-generic.cpp b/src/VBox/Runtime/r3/generic/semspinmutex-r3-generic.cpp
new file mode 100644
index 00000000..ae6d7c5e
--- /dev/null
+++ b/src/VBox/Runtime/r3/generic/semspinmutex-r3-generic.cpp
@@ -0,0 +1,103 @@
+/* $Id: semspinmutex-r3-generic.cpp $ */
+/** @file
+ * IPRT - Spinning Mutex Semaphores, Ring-3, Generic.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloc.h>
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+
+
+
+RTDECL(int) RTSemSpinMutexCreate(PRTSEMSPINMUTEX phSpinMtx, uint32_t fFlags)
+{
+    AssertReturn(!(fFlags & ~RTSEMSPINMUTEX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtr(phSpinMtx);
+
+    PRTCRITSECT pCritSect = (PRTCRITSECT)RTMemAlloc(sizeof(RTCRITSECT));
+    if (!pCritSect)
+        return VERR_NO_MEMORY;
+    int rc = RTCritSectInitEx(pCritSect, RTCRITSECT_FLAGS_NO_NESTING | RTCRITSECT_FLAGS_NO_LOCK_VAL,
+                              NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemSpinMutex");
+    if (RT_SUCCESS(rc))
+        *phSpinMtx = (RTSEMSPINMUTEX)pCritSect;
+    else
+        RTMemFree(pCritSect);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSemSpinMutexCreate);
+
+
+RTDECL(int) RTSemSpinMutexDestroy(RTSEMSPINMUTEX hSpinMtx)
+{
+    if (hSpinMtx == NIL_RTSEMSPINMUTEX)
+        return VERR_INVALID_PARAMETER;
+    PRTCRITSECT pCritSect = (PRTCRITSECT)hSpinMtx;
+    int rc = RTCritSectDelete(pCritSect);
+    if (RT_SUCCESS(rc))
+        RTMemFree(pCritSect);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSemSpinMutexDestroy);
+
+
+RTDECL(int) RTSemSpinMutexTryRequest(RTSEMSPINMUTEX hSpinMtx)
+{
+    return RTCritSectTryEnter((PRTCRITSECT)hSpinMtx);
+
+}
+RT_EXPORT_SYMBOL(RTSemSpinMutexTryRequest);
+
+
+RTDECL(int) RTSemSpinMutexRequest(RTSEMSPINMUTEX hSpinMtx)
+{
+    return RTCritSectEnter((PRTCRITSECT)hSpinMtx);
+}
+RT_EXPORT_SYMBOL(RTSemSpinMutexRequest);
+
+
+RTDECL(int) RTSemSpinMutexRelease(RTSEMSPINMUTEX hSpinMtx)
+{
+    return RTCritSectLeave((PRTCRITSECT)hSpinMtx);
+}
+RT_EXPORT_SYMBOL(RTSemSpinMutexRelease);
+
diff --git a/src/VBox/Runtime/r3/haiku/Makefile.kup b/src/VBox/Runtime/r3/haiku/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/haiku/Makefile.kup
diff --git a/src/VBox/Runtime/r3/haiku/rtProcInitExePath-haiku.cpp b/src/VBox/Runtime/r3/haiku/rtProcInitExePath-haiku.cpp
new file mode 100644
index 00000000..51905b73
--- /dev/null
+++ b/src/VBox/Runtime/r3/haiku/rtProcInitExePath-haiku.cpp
@@ -0,0 +1,71 @@
+/* $Id: rtProcInitExePath-haiku.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, Haiku.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#ifdef RT_OS_HAIKU
+# include <image.h>
+#endif
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    image_info ImageInfo;
+    int32 Cookie = 0;
+    status_t status;
+
+    /*
+     * Query the image name from the OS, convert and return it.
+     */
+    status = get_next_image_info(0, &Cookie, &ImageInfo);
+    AssertReturn((status == B_OK), VERR_INTERNAL_ERROR);
+
+    int rc = rtPathFromNativeCopy(pszPath, MIN(cchPath, MAXPATHLEN), ImageInfo.name, NULL);
+    AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, MIN(cchPath, MAXPATHLEN), pszPath), rc);
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/haiku/time-haiku.cpp b/src/VBox/Runtime/r3/haiku/time-haiku.cpp
new file mode 100644
index 00000000..a6419b83
--- /dev/null
+++ b/src/VBox/Runtime/r3/haiku/time-haiku.cpp
@@ -0,0 +1,95 @@
+/* $Id: time-haiku.cpp $ */
+/** @file
+ * IPRT - Time, Haiku.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <sys/time.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <OS.h>
+
+#include <iprt/time.h>
+#include <iprt/errcore.h>
+#include "internal/time.h"
+
+
+DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
+{
+    return (uint64_t)system_time() * RT_NS_1US;
+}
+
+
+/**
+ * Gets the current nanosecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns nanosecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+/**
+ * Gets the current millisecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns millisecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
+
+RTDECL(int) RTTimeSet(PCRTTIMESPEC pTime)
+{
+    struct timeval tv;
+    RTTimeSpecGetTimeval(pTime, &tv);
+    set_real_time_clock(tv.tv_sec);
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/http-server.cpp b/src/VBox/Runtime/r3/http-server.cpp
new file mode 100644
index 00000000..93c3f3fa
--- /dev/null
+++ b/src/VBox/Runtime/r3/http-server.cpp
@@ -0,0 +1,1455 @@
+/* $Id: http-server.cpp $ */
+/** @file
+ * Simple HTTP server (RFC 7231) implementation.
+ *
+ * Known limitations so far:
+ * - Only HTTP 1.1.
+ * - Only supports GET + HEAD methods so far.
+ * - Only supports UTF-8 charset.
+ * - Only supports plain text and octet stream MIME types.
+ * - No content compression ("gzip", "x-gzip", ++).
+ * - No caching.
+ * - No redirections (via 302).
+ * - No encryption (TLS).
+ * - No IPv6 support.
+ * - No multi-threading.
+ *
+ * For WebDAV (optional via IPRT_HTTP_WITH_WEBDAV):
+ * - Only OPTIONS + PROPLIST methods are implemented (e.g. simple read-only support).
+ * - No pagination support for directory listings.
+ */
+
+/*
+ * Copyright (C) 2020-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_HTTP
+#include <iprt/http.h>
+#include <iprt/http-server.h>
+#include "internal/iprt.h"
+#include "internal/magics.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/circbuf.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/file.h> /* For file mode flags. */
+#include <iprt/getopt.h>
+#include <iprt/mem.h>
+#include <iprt/log.h>
+#include <iprt/path.h>
+#include <iprt/poll.h>
+#include <iprt/socket.h>
+#include <iprt/sort.h>
+#include <iprt/string.h>
+#include <iprt/system.h>
+#include <iprt/tcp.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Internal HTTP server instance.
+ */
+typedef struct RTHTTPSERVERINTERNAL
+{
+    /** Magic value. */
+    uint32_t                u32Magic;
+    /** Callback table. */
+    RTHTTPSERVERCALLBACKS   Callbacks;
+    /** Pointer to TCP server instance. */
+    PRTTCPSERVER            pTCPServer;
+    /** Pointer to user-specific data. Optional. */
+    void                   *pvUser;
+    /** Size of user-specific data. Optional. */
+    size_t                  cbUser;
+} RTHTTPSERVERINTERNAL;
+/** Pointer to an internal HTTP server instance. */
+typedef RTHTTPSERVERINTERNAL *PRTHTTPSERVERINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Validates a handle and returns VERR_INVALID_HANDLE if not valid. */
+#define RTHTTPSERVER_VALID_RETURN_RC(hHttpServer, a_rc) \
+    do { \
+        AssertPtrReturn((hHttpServer), (a_rc)); \
+        AssertReturn((hHttpServer)->u32Magic == RTHTTPSERVER_MAGIC, (a_rc)); \
+    } while (0)
+
+/** Validates a handle and returns VERR_INVALID_HANDLE if not valid. */
+#define RTHTTPSERVER_VALID_RETURN(hHttpServer) RTHTTPSERVER_VALID_RETURN_RC((hHttpServer), VERR_INVALID_HANDLE)
+
+/** Validates a handle and returns (void) if not valid. */
+#define RTHTTPSERVER_VALID_RETURN_VOID(hHttpServer) \
+    do { \
+        AssertPtrReturnVoid(hHttpServer); \
+        AssertReturnVoid((hHttpServer)->u32Magic == RTHTTPSERVER_MAGIC); \
+    } while (0)
+
+
+/** Handles a HTTP server callback with no arguments and returns. */
+#define RTHTTPSERVER_HANDLE_CALLBACK_RET(a_Name) \
+    do \
+    { \
+        PRTHTTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTHTTPCALLBACKDATA Data = { &pClient->State }; \
+            return pCallbacks->a_Name(&Data); \
+        } \
+        return VERR_NOT_IMPLEMENTED; \
+    } while (0)
+
+/** Handles a HTTP server callback with no arguments and sets rc accordingly. */
+#define RTHTTPSERVER_HANDLE_CALLBACK(a_Name) \
+    do \
+    { \
+        PRTHTTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTHTTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            rc = pCallbacks->a_Name(&Data); \
+        } \
+    } while (0)
+
+/** Handles a HTTP server callback with arguments and sets rc accordingly. */
+#define RTHTTPSERVER_HANDLE_CALLBACK_VA(a_Name, ...) \
+    do \
+    { \
+        PRTHTTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTHTTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            rc = pCallbacks->a_Name(&Data, __VA_ARGS__); \
+        } \
+    } while (0)
+
+/** Handles a HTTP server callback with arguments and returns. */
+#define RTHTTPSERVER_HANDLE_CALLBACK_VA_RET(a_Name, ...) \
+    do \
+    { \
+        PRTHTTPSERVERCALLBACKS pCallbacks = &pClient->pServer->Callbacks; \
+        if (pCallbacks->a_Name) \
+        { \
+            RTHTTPCALLBACKDATA Data = { &pClient->State, pClient->pServer->pvUser, pClient->pServer->cbUser }; \
+            return pCallbacks->a_Name(&Data, __VA_ARGS__); \
+        } \
+    } while (0)
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Structure for maintaining an internal HTTP server client.
+ */
+typedef struct RTHTTPSERVERCLIENT
+{
+    /** Pointer to internal server state. */
+    PRTHTTPSERVERINTERNAL       pServer;
+    /** Socket handle the client is bound to. */
+    RTSOCKET                    hSocket;
+    /** Actual client state. */
+    RTHTTPSERVERCLIENTSTATE     State;
+} RTHTTPSERVERCLIENT;
+/** Pointer to an internal HTTP server client state. */
+typedef RTHTTPSERVERCLIENT *PRTHTTPSERVERCLIENT;
+
+/** Function pointer declaration for a specific HTTP server method handler. */
+typedef DECLCALLBACKTYPE(int, FNRTHTTPSERVERMETHOD,(PRTHTTPSERVERCLIENT pClient, PRTHTTPSERVERREQ pReq));
+/** Pointer to a FNRTHTTPSERVERMETHOD(). */
+typedef FNRTHTTPSERVERMETHOD *PFNRTHTTPSERVERMETHOD;
+
+/**
+ * Static lookup table for some file extensions <-> MIME type. Add more as needed.
+ * Keep this alphabetical (file extension).
+ */
+static const struct
+{
+    /** File extension. */
+    const char *pszExt;
+    /** MIME type. */
+    const char *pszMIMEType;
+} s_aFileExtMIMEType[] = {
+    { ".arj",     "application/x-arj-compressed" },
+    { ".asf",     "video/x-ms-asf" },
+    { ".avi",     "video/x-msvideo" },
+    { ".bmp",     "image/bmp" },
+    { ".css",     "text/css" },
+    { ".doc",     "application/msword" },
+    { ".exe",     "application/octet-stream" },
+    { ".gif",     "image/gif" },
+    { ".gz",      "application/x-gunzip" },
+    { ".htm",     "text/html" },
+    { ".html",    "text/html" },
+    { ".ico",     "image/x-icon" },
+    { ".js",      "application/x-javascript" },
+    { ".json",    "text/json" },
+    { ".jpg",     "image/jpeg" },
+    { ".jpeg",    "image/jpeg" },
+    { ".ogg",     "application/ogg" },
+    { ".m3u",     "audio/x-mpegurl" },
+    { ".m4v",     "video/x-m4v" },
+    { ".mid",     "audio/mid" },
+    { ".mov",     "video/quicktime" },
+    { ".mp3",     "audio/x-mp3" },
+    { ".mp4",     "video/mp4" },
+    { ".mpg",     "video/mpeg" },
+    { ".mpeg",    "video/mpeg" },
+    { ".pdf",     "application/pdf" },
+    { ".png",     "image/png" },
+    { ".ra",      "audio/x-pn-realaudio" },
+    { ".ram",     "audio/x-pn-realaudio" },
+    { ".rar",     "application/x-arj-compressed" },
+    { ".rtf",     "application/rtf" },
+    { ".shtm",    "text/html" },
+    { ".shtml",   "text/html" },
+    { ".svg",     "image/svg+xml" },
+    { ".swf",     "application/x-shockwave-flash" },
+    { ".torrent", "application/x-bittorrent" },
+    { ".tar",     "application/x-tar" },
+    { ".tgz",     "application/x-tar-gz" },
+    { ".ttf",     "application/x-font-ttf" },
+    { ".txt",     "text/plain" },
+    { ".wav",     "audio/x-wav" },
+    { ".webm",    "video/webm" },
+    { ".xml",     "text/xml" },
+    { ".xls",     "application/excel" },
+    { ".xsl",     "application/xml" },
+    { ".xslt",    "application/xml" },
+    { ".zip",     "application/x-zip-compressed" },
+    { NULL,       NULL }
+};
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/** @name Method handlers.
+ * @{
+ */
+static FNRTHTTPSERVERMETHOD  rtHttpServerHandleGET;
+static FNRTHTTPSERVERMETHOD  rtHttpServerHandleHEAD;
+#ifdef IPRT_HTTP_WITH_WEBDAV
+ static FNRTHTTPSERVERMETHOD rtHttpServerHandleOPTIONS;
+ static FNRTHTTPSERVERMETHOD rtHttpServerHandlePROPFIND;
+#endif
+/** @} */
+
+/**
+ * Structure for maintaining a single method entry for the methods table.
+ */
+typedef struct RTHTTPSERVERMETHOD_ENTRY
+{
+    /** Method ID. */
+    RTHTTPMETHOD          enmMethod;
+    /** Function pointer invoked to handle the command. */
+    PFNRTHTTPSERVERMETHOD pfnMethod;
+} RTHTTPSERVERMETHOD_ENTRY;
+/** Pointer to a command entry. */
+typedef RTHTTPSERVERMETHOD_ENTRY *PRTHTTPMETHOD_ENTRY;
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Table of handled methods.
+ */
+static const RTHTTPSERVERMETHOD_ENTRY g_aMethodMap[] =
+{
+    { RTHTTPMETHOD_GET,      rtHttpServerHandleGET },
+    { RTHTTPMETHOD_HEAD,     rtHttpServerHandleHEAD },
+#ifdef IPRT_HTTP_WITH_WEBDAV
+    { RTHTTPMETHOD_OPTIONS,  rtHttpServerHandleOPTIONS },
+    { RTHTTPMETHOD_PROPFIND, rtHttpServerHandlePROPFIND },
+#endif
+    { RTHTTPMETHOD_END,  NULL }
+};
+
+/** Maximum length in characters a HTTP server path can have (excluding termination). */
+#define RTHTTPSERVER_MAX_PATH        RTPATH_MAX
+
+
+/*********************************************************************************************************************************
+*   Internal functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Guesses the HTTP MIME type based on a given file extension.
+ *
+ * Note: Has to include the beginning dot, e.g. ".mp3" (see IPRT).
+ *
+ * @returns Guessed MIME type, or "application/octet-stream" if not found.
+ * @param   pszFileExt          File extension to guess MIME type for.
+ */
+static const char *rtHttpServerGuessMIMEType(const char *pszFileExt)
+{
+    if (pszFileExt)
+    {
+        size_t i = 0;
+        while (s_aFileExtMIMEType[i++].pszExt) /* Slow, but does the job for now. */
+        {
+            if (!RTStrICmp(pszFileExt, s_aFileExtMIMEType[i].pszExt))
+                return s_aFileExtMIMEType[i].pszMIMEType;
+        }
+    }
+
+    return "application/octet-stream";
+}
+
+/**
+ * Initializes a HTTP body.
+ *
+ * @param   pBody               Body to initialize.
+ * @param   cbSize              Size of body (in bytes) to allocate. Optional and can be 0.
+ */
+static int rtHttpServerBodyInit(PRTHTTPBODY pBody, size_t cbSize)
+{
+    if (cbSize)
+    {
+        pBody->pvBody      = RTMemAlloc(cbSize);
+        AssertPtrReturn(pBody->pvBody, VERR_NO_MEMORY);
+        pBody->cbBodyAlloc = cbSize;
+    }
+    else
+    {
+        pBody->pvBody      = NULL;
+        pBody->cbBodyAlloc = 0;
+    }
+
+    pBody->cbBodyUsed = 0;
+    pBody->offBody    = 0;
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Destroys a HTTP body.
+ *
+ * @param   pBody               Body to destroy.
+ */
+static void rtHttpServerBodyDestroy(PRTHTTPBODY pBody)
+{
+    if (!pBody)
+        return;
+
+    if (pBody->pvBody)
+    {
+        Assert(pBody->cbBodyAlloc);
+
+        RTMemFree(pBody->pvBody);
+        pBody->pvBody = NULL;
+    }
+
+    pBody->cbBodyAlloc  = 0;
+    pBody->cbBodyUsed   = 0;
+    pBody->offBody      = 0;
+}
+
+/**
+ * Allocates and initializes a new client request.
+ *
+ * @returns Pointer to the new client request, or NULL on OOM.
+ *          Needs to be free'd with rtHttpServerReqFree().
+ */
+static PRTHTTPSERVERREQ rtHttpServerReqAlloc(void)
+{
+    PRTHTTPSERVERREQ pReq = (PRTHTTPSERVERREQ)RTMemAllocZ(sizeof(RTHTTPSERVERREQ));
+    AssertPtrReturn(pReq, NULL);
+
+    int rc2 = RTHttpHeaderListInit(&pReq->hHdrLst);
+    AssertRC(rc2);
+
+    rc2 = rtHttpServerBodyInit(&pReq->Body, 0 /* cbSize */);
+    AssertRC(rc2);
+
+    return pReq;
+}
+
+/**
+ * Frees a formerly allocated client request.
+ *
+ * @param   pReq                Pointer to client request to free.
+ *                              The pointer will be invalid on return.
+ */
+static void rtHttpServerReqFree(PRTHTTPSERVERREQ pReq)
+{
+    if (!pReq)
+        return;
+
+    RTStrFree(pReq->pszUrl);
+
+    RTHttpHeaderListDestroy(pReq->hHdrLst);
+
+    rtHttpServerBodyDestroy(&pReq->Body);
+
+    RTMemFree(pReq);
+    pReq = NULL;
+}
+
+/**
+ * Initializes a HTTP server response with an allocated body size.
+ *
+ * @returns VBox status code.
+ * @param   pResp               HTTP server response to initialize.
+ * @param   cbBody              Body size (in bytes) to allocate.
+ */
+RTR3DECL(int) RTHttpServerResponseInitEx(PRTHTTPSERVERRESP pResp, size_t cbBody)
+{
+    pResp->enmSts = RTHTTPSTATUS_INTERNAL_NOT_SET;
+
+    int rc = RTHttpHeaderListInit(&pResp->hHdrLst);
+    AssertRCReturn(rc, rc);
+
+    rc = rtHttpServerBodyInit(&pResp->Body, cbBody);
+
+    return rc;
+}
+
+/**
+ * Initializes a HTTP server response.
+ *
+ * @returns VBox status code.
+ * @param   pResp               HTTP server response to initialize.
+ */
+RTR3DECL(int) RTHttpServerResponseInit(PRTHTTPSERVERRESP pResp)
+{
+    return RTHttpServerResponseInitEx(pResp, 0 /* cbBody */);
+}
+
+/**
+ * Destroys a formerly initialized HTTP server response.
+ *
+ * @param   pResp               Pointer to HTTP server response to destroy.
+ */
+RTR3DECL(void) RTHttpServerResponseDestroy(PRTHTTPSERVERRESP pResp)
+{
+    if (!pResp)
+        return;
+
+    pResp->enmSts = RTHTTPSTATUS_INTERNAL_NOT_SET;
+
+    RTHttpHeaderListDestroy(pResp->hHdrLst);
+
+    rtHttpServerBodyDestroy(&pResp->Body);
+}
+
+
+/*********************************************************************************************************************************
+*   Protocol Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Logs the HTTP protocol communication to the debug logger (2).
+ *
+ * @param   pClient             Client to log communication for.
+ * @param   fWrite              Whether the server is writing (to client) or reading (from client).
+ * @param   pszData             Actual protocol communication data to log.
+ */
+static void rtHttpServerLogProto(PRTHTTPSERVERCLIENT pClient, bool fWrite, const char *pszData)
+{
+    RT_NOREF(pClient);
+
+#ifdef LOG_ENABLED
+    if (!pszData) /* Nothing to log? Bail out. */
+        return;
+
+    char **ppapszStrings;
+    size_t cStrings;
+    int rc2 = RTStrSplit(pszData, strlen(pszData), RTHTTPSERVER_HTTP11_EOL_STR, &ppapszStrings, &cStrings);
+    if (RT_SUCCESS(rc2))
+    {
+        for (size_t i = 0; i < cStrings; i++)
+        {
+            Log2(("%s %s\n", fWrite ? ">" : "<", ppapszStrings[i]));
+            RTStrFree(ppapszStrings[i]);
+        }
+
+        RTMemFree(ppapszStrings);
+    }
+#else
+    RT_NOREF(fWrite, pszData);
+#endif
+}
+
+/**
+ * Writes HTTP protocol communication data to a connected client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to write data to.
+ * @param   pszData             Data to write. Must be zero-terminated.
+ */
+static int rtHttpServerWriteProto(PRTHTTPSERVERCLIENT pClient, const char *pszData)
+{
+    rtHttpServerLogProto(pClient, true /* fWrite */, pszData);
+    return RTTcpWrite(pClient->hSocket, pszData, strlen(pszData));
+}
+
+/**
+ * Main function for sending a response back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   enmSts              Status code to send.
+ */
+static int rtHttpServerSendResponse(PRTHTTPSERVERCLIENT pClient, RTHTTPSTATUS enmSts)
+{
+    char *pszResp;
+    int rc = RTStrAPrintf(&pszResp,
+                          "%s %RU32 %s\r\n", RTHTTPVER_1_1_STR, enmSts, RTHttpStatusToStr(enmSts));
+    AssertRCReturn(rc, rc);
+    rc = rtHttpServerWriteProto(pClient, pszResp);
+    RTStrFree(pszResp);
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Main function for sending response headers back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   pHdrLst             Header list to send. Optional and can be NULL.
+ */
+static int rtHttpServerSendResponseHdrEx(PRTHTTPSERVERCLIENT pClient, PRTHTTPHEADERLIST pHdrLst)
+{
+    RTHTTPHEADERLIST HdrLst;
+    int rc = RTHttpHeaderListInit(&HdrLst);
+    AssertRCReturn(rc, rc);
+
+#ifdef DEBUG
+    /* Include a timestamp when running a debug build. */
+    RTTIMESPEC tsNow;
+    char szTS[64];
+    RTTimeSpecToString(RTTimeNow(&tsNow), szTS, sizeof(szTS));
+    rc = RTHttpHeaderListAdd(HdrLst, "Date",  szTS, strlen(szTS), RTHTTPHEADERLISTADD_F_BACK);
+    AssertRCReturn(rc, rc);
+#endif
+
+    /* Note: Deliberately don't include the VBox version due to security reasons. */
+    rc = RTHttpHeaderListAdd(HdrLst, "Server", "Oracle VirtualBox", strlen("Oracle VirtualBox"), RTHTTPHEADERLISTADD_F_BACK);
+    AssertRCReturn(rc, rc);
+
+#ifdef IPRT_HTTP_WITH_WEBDAV
+    rc = RTHttpHeaderListAdd(HdrLst, "Allow", "GET, HEAD, PROPFIND", strlen("GET, HEAD, PROPFIND"), RTHTTPHEADERLISTADD_F_BACK);
+    AssertRCReturn(rc, rc);
+    rc = RTHttpHeaderListAdd(HdrLst, "DAV", "1", strlen("1"), RTHTTPHEADERLISTADD_F_BACK); /* Note: v1 is sufficient for read-only access. */
+    AssertRCReturn(rc, rc);
+#endif
+
+    char *pszHdr = NULL;
+
+    size_t i = 0;
+    const char *pszEntry;
+    while ((pszEntry = RTHttpHeaderListGetByOrdinal(HdrLst, i++)) != NULL)
+    {
+        rc = RTStrAAppend(&pszHdr, pszEntry);
+        AssertRCBreak(rc);
+        rc = RTStrAAppend(&pszHdr, RTHTTPSERVER_HTTP11_EOL_STR);
+        AssertRCBreak(rc);
+    }
+
+    /* Append optional headers, if any. */
+    if (pHdrLst)
+    {
+        i = 0;
+        while ((pszEntry = RTHttpHeaderListGetByOrdinal(*pHdrLst, i++)) != NULL)
+        {
+            rc = RTStrAAppend(&pszHdr, pszEntry);
+            AssertRCBreak(rc);
+            rc = RTStrAAppend(&pszHdr, RTHTTPSERVER_HTTP11_EOL_STR);
+            AssertRCBreak(rc);
+        }
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        /* Append trailing EOL. */
+        rc = RTStrAAppend(&pszHdr, RTHTTPSERVER_HTTP11_EOL_STR);
+        if (RT_SUCCESS(rc))
+            rc = rtHttpServerWriteProto(pClient, pszHdr);
+    }
+
+    RTStrFree(pszHdr);
+
+    RTHttpHeaderListDestroy(HdrLst);
+
+    LogFlowFunc(("rc=%Rrc\n", rc));
+    return rc;
+}
+
+/**
+ * Replies with (three digit) response status back to the client, extended version.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   enmSts              Status code to send.
+ * @param   pHdrLst             Header list to send. Optional and can be NULL.
+ */
+static int rtHttpServerSendResponseEx(PRTHTTPSERVERCLIENT pClient, RTHTTPSTATUS enmSts, PRTHTTPHEADERLIST pHdrLst)
+{
+    int rc = rtHttpServerSendResponse(pClient, enmSts);
+    if (RT_SUCCESS(rc))
+        rc = rtHttpServerSendResponseHdrEx(pClient, pHdrLst);
+
+    return rc;
+}
+
+/**
+ * Replies with (three digit) response status back to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to reply to.
+ * @param   enmSts              Status code to send.
+ */
+static int rtHttpServerSendResponseSimple(PRTHTTPSERVERCLIENT pClient, RTHTTPSTATUS enmSts)
+{
+    return rtHttpServerSendResponseEx(pClient, enmSts, NULL /* pHdrLst */);
+}
+
+/**
+ * Sends a chunk of the response body to the client.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to send body to.
+ * @param   pvBuf               Data buffer to send.
+ * @param   cbBuf               Size (in bytes) of data buffer to send.
+ * @param   pcbSent             Where to store the sent bytes. Optional and can be NULL.
+ */
+static int rtHttpServerSendResponseBody(PRTHTTPSERVERCLIENT pClient, void *pvBuf, size_t cbBuf, size_t *pcbSent)
+{
+    int rc = RTTcpWrite(pClient->hSocket, pvBuf, cbBuf);
+    if (   RT_SUCCESS(rc)
+        && pcbSent)
+        *pcbSent = cbBuf;
+
+    return rc;
+}
+
+/**
+ * Resolves a VBox status code to a HTTP status code.
+ *
+ * @returns Resolved HTTP status code, or RTHTTPSTATUS_INTERNALSERVERERROR if not able to resolve.
+ * @param   rc                  VBox status code to resolve.
+ */
+static RTHTTPSTATUS rtHttpServerRcToStatus(int rc)
+{
+    switch (rc)
+    {
+        case VINF_SUCCESS:              return RTHTTPSTATUS_OK;
+        case VERR_INVALID_PARAMETER:    return RTHTTPSTATUS_BADREQUEST;
+        case VERR_INVALID_POINTER:      return RTHTTPSTATUS_BADREQUEST;
+        case VERR_NOT_IMPLEMENTED:      return RTHTTPSTATUS_NOTIMPLEMENTED;
+        case VERR_NOT_SUPPORTED:        return RTHTTPSTATUS_NOTIMPLEMENTED;
+        case VERR_PATH_NOT_FOUND:       return RTHTTPSTATUS_NOTFOUND;
+        case VERR_FILE_NOT_FOUND:       return RTHTTPSTATUS_NOTFOUND;
+        case VERR_IS_A_DIRECTORY:       return RTHTTPSTATUS_FORBIDDEN;
+        case VERR_NOT_FOUND:            return RTHTTPSTATUS_NOTFOUND;
+        default:
+            break;
+    }
+
+    AssertMsgFailed(("rc=%Rrc not handled for HTTP status\n", rc));
+    return RTHTTPSTATUS_INTERNALSERVERERROR;
+}
+
+
+/*********************************************************************************************************************************
+*   Command Protocol Handlers                                                                                                    *
+*********************************************************************************************************************************/
+
+/**
+ * Handler for the GET method.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to handle GET method for.
+ * @param   pReq                Client request to handle.
+ */
+static DECLCALLBACK(int) rtHttpServerHandleGET(PRTHTTPSERVERCLIENT pClient, PRTHTTPSERVERREQ pReq)
+{
+    LogFlowFuncEnter();
+
+    int rc = VINF_SUCCESS;
+
+    /* If a low-level GET request handler is defined, call it and return. */
+    RTHTTPSERVER_HANDLE_CALLBACK_VA_RET(pfnOnGetRequest, pReq);
+
+    RTFSOBJINFO fsObj;
+    RT_ZERO(fsObj); /* Shut up MSVC. */
+
+    char *pszMIMEHint = NULL;
+
+    RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnQueryInfo, pReq, &fsObj, &pszMIMEHint);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    void *pvHandle = NULL;
+    RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnOpen, pReq, &pvHandle);
+
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbBuf = _64K;
+        void  *pvBuf = RTMemAlloc(cbBuf);
+        AssertPtrReturn(pvBuf, VERR_NO_MEMORY);
+
+        for (;;)
+        {
+            RTHTTPHEADERLIST HdrLst;
+            rc = RTHttpHeaderListInit(&HdrLst);
+            AssertRCReturn(rc, rc);
+
+            char szVal[16];
+
+            /* Note: For directories fsObj.cbObject contains the actual size (in bytes)
+             *       of the body data for the directory listing. */
+
+            ssize_t cch = RTStrPrintf2(szVal, sizeof(szVal), "%RU64", fsObj.cbObject);
+            AssertBreakStmt(cch, VERR_BUFFER_OVERFLOW);
+            rc = RTHttpHeaderListAdd(HdrLst, "Content-Length", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+            AssertRCBreak(rc);
+
+            cch = RTStrPrintf2(szVal, sizeof(szVal), "identity");
+            AssertBreakStmt(cch, VERR_BUFFER_OVERFLOW);
+            rc = RTHttpHeaderListAdd(HdrLst, "Content-Encoding", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+            AssertRCBreak(rc);
+
+            if (pszMIMEHint == NULL)
+            {
+                const char *pszMIME = rtHttpServerGuessMIMEType(RTPathSuffix(pReq->pszUrl));
+                rc = RTHttpHeaderListAdd(HdrLst, "Content-Type", pszMIME, strlen(pszMIME), RTHTTPHEADERLISTADD_F_BACK);
+            }
+            else
+            {
+                rc = RTHttpHeaderListAdd(HdrLst, "Content-Type", pszMIMEHint, strlen(pszMIMEHint), RTHTTPHEADERLISTADD_F_BACK);
+                RTStrFree(pszMIMEHint);
+                pszMIMEHint = NULL;
+            }
+            AssertRCBreak(rc);
+
+            if (pClient->State.msKeepAlive)
+            {
+                /* If the client requested to keep alive the connection,
+                 * always override this with 30s and report this back to the client. */
+                pClient->State.msKeepAlive = RT_MS_30SEC; /** @todo Make this configurable. */
+#ifdef DEBUG_andy
+                pClient->State.msKeepAlive = 5000;
+#endif
+                cch = RTStrPrintf2(szVal, sizeof(szVal), "timeout=%RU64", pClient->State.msKeepAlive / RT_MS_1SEC); /** @todo No pipelining support here yet. */
+                AssertBreakStmt(cch, VERR_BUFFER_OVERFLOW);
+                rc = RTHttpHeaderListAdd(HdrLst, "Keep-Alive", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+                AssertRCReturn(rc, rc);
+            }
+
+            rc = rtHttpServerSendResponseEx(pClient, RTHTTPSTATUS_OK, &HdrLst);
+
+            RTHttpHeaderListDestroy(HdrLst);
+
+            if (rc == VERR_BROKEN_PIPE) /* Could happen on fast reloads. */
+                break;
+            AssertRCReturn(rc, rc);
+
+            size_t cbToRead  = fsObj.cbObject;
+            size_t cbRead    = 0; /* Shut up GCC. */
+            size_t cbWritten = 0; /* Ditto. */
+            while (cbToRead)
+            {
+                RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnRead, pvHandle, pvBuf, RT_MIN(cbBuf, cbToRead), &cbRead);
+                if (RT_FAILURE(rc))
+                    break;
+                rc = rtHttpServerSendResponseBody(pClient, pvBuf, cbRead, &cbWritten);
+                AssertBreak(cbToRead >= cbWritten);
+                cbToRead -= cbWritten;
+                if (rc == VERR_NET_CONNECTION_RESET_BY_PEER) /* Clients often apruptly abort the connection when done. */
+                {
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+                AssertRCBreak(rc);
+            }
+
+            break;
+        } /* for (;;) */
+
+        RTMemFree(pvBuf);
+
+        int rc2 = rc; /* Save rc. */
+
+        RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnClose, pvHandle);
+
+        if (RT_FAILURE(rc2)) /* Restore original rc on failure. */
+            rc = rc2;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Handler for the HEAD method.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to handle HEAD method for.
+ * @param   pReq                Client request to handle.
+ */
+static DECLCALLBACK(int) rtHttpServerHandleHEAD(PRTHTTPSERVERCLIENT pClient, PRTHTTPSERVERREQ pReq)
+{
+    LogFlowFuncEnter();
+
+    /* If a low-level HEAD request handler is defined, call it and return. */
+    RTHTTPSERVER_HANDLE_CALLBACK_VA_RET(pfnOnHeadRequest, pReq);
+
+    int rc = VINF_SUCCESS;
+
+    RTFSOBJINFO fsObj;
+    RT_ZERO(fsObj); /* Shut up MSVC. */
+
+    RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnQueryInfo, pReq, &fsObj, NULL /* pszMIMEHint */);
+    if (RT_SUCCESS(rc))
+    {
+        RTHTTPHEADERLIST HdrLst;
+        rc = RTHttpHeaderListInit(&HdrLst);
+        AssertRCReturn(rc, rc);
+
+        /*
+         * Note: A response to a HEAD request does not have a body.
+         * All entity headers below are assumed to describe the the response a similar GET
+         * request would return (but then with a body).
+         */
+        char szVal[16];
+
+        ssize_t cch = RTStrPrintf2(szVal, sizeof(szVal), "%RU64", fsObj.cbObject);
+        AssertReturn(cch, VERR_BUFFER_OVERFLOW);
+        rc = RTHttpHeaderListAdd(HdrLst, "Content-Length", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+        AssertRCReturn(rc, rc);
+
+        cch = RTStrPrintf2(szVal, sizeof(szVal), "identity");
+        AssertReturn(cch, VERR_BUFFER_OVERFLOW);
+        rc = RTHttpHeaderListAdd(HdrLst, "Content-Encoding", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+        AssertRCReturn(rc, rc);
+
+        const char *pszMIME = rtHttpServerGuessMIMEType(RTPathSuffix(pReq->pszUrl));
+        rc = RTHttpHeaderListAdd(HdrLst, "Content-Type", pszMIME, strlen(pszMIME), RTHTTPHEADERLISTADD_F_BACK);
+        AssertRCReturn(rc, rc);
+
+        rc = rtHttpServerSendResponseEx(pClient, RTHTTPSTATUS_OK, &HdrLst);
+        AssertRCReturn(rc, rc);
+
+        RTHttpHeaderListDestroy(HdrLst);
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+#ifdef IPRT_HTTP_WITH_WEBDAV
+/**
+ * Handler for the OPTIONS method.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to handle OPTIONS method for.
+ * @param   pReq                Client request to handle.
+ */
+static DECLCALLBACK(int) rtHttpServerHandleOPTIONS(PRTHTTPSERVERCLIENT pClient, PRTHTTPSERVERREQ pReq)
+{
+    LogFlowFuncEnter();
+
+    RT_NOREF(pReq);
+
+    int rc = rtHttpServerSendResponseEx(pClient, RTHTTPSTATUS_OK, NULL /* pHdrLst */);
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Handler for the PROPFIND (WebDAV) method.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to handle PROPFIND method for.
+ * @param   pReq                Client request to handle.
+ */
+static DECLCALLBACK(int) rtHttpServerHandlePROPFIND(PRTHTTPSERVERCLIENT pClient, PRTHTTPSERVERREQ pReq)
+{
+    LogFlowFuncEnter();
+
+    int rc = VINF_SUCCESS;
+
+    /* If a low-level GET request handler is defined, call it and return. */
+    RTHTTPSERVER_HANDLE_CALLBACK_VA_RET(pfnOnGetRequest, pReq);
+
+    RTFSOBJINFO fsObj;
+    RT_ZERO(fsObj); /* Shut up MSVC. */
+
+    RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnQueryInfo, pReq, &fsObj, NULL /* pszMIMEHint */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    void *pvHandle = NULL;
+    RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnOpen, pReq, &pvHandle);
+
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbBuf = _64K;
+        void  *pvBuf = RTMemAlloc(cbBuf);
+        AssertPtrReturn(pvBuf, VERR_NO_MEMORY);
+
+        for (;;)
+        {
+            RTHTTPHEADERLIST HdrLst;
+            rc = RTHttpHeaderListInit(&HdrLst);
+            AssertRCReturn(rc, rc);
+
+            char szVal[16];
+
+            rc = RTHttpHeaderListAdd(HdrLst, "Content-Type", "text/xml; charset=utf-8", strlen("text/xml; charset=utf-8"), RTHTTPHEADERLISTADD_F_BACK);
+            AssertRCBreak(rc);
+
+            /* Note: For directories fsObj.cbObject contains the actual size (in bytes)
+             *       of the body data for the directory listing. */
+
+            ssize_t cch = RTStrPrintf2(szVal, sizeof(szVal), "%RU64", fsObj.cbObject);
+            AssertBreakStmt(cch, VERR_BUFFER_OVERFLOW);
+            rc = RTHttpHeaderListAdd(HdrLst, "Content-Length", szVal, strlen(szVal), RTHTTPHEADERLISTADD_F_BACK);
+            AssertRCBreak(rc);
+
+            rc = rtHttpServerSendResponseEx(pClient, RTHTTPSTATUS_MULTISTATUS, &HdrLst);
+            AssertRCReturn(rc, rc);
+
+            RTHttpHeaderListDestroy(HdrLst);
+
+            size_t cbToRead  = fsObj.cbObject;
+            size_t cbRead    = 0; /* Shut up GCC. */
+            size_t cbWritten = 0; /* Ditto. */
+            while (cbToRead)
+            {
+                RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnRead, pvHandle, pvBuf, RT_MIN(cbBuf, cbToRead), &cbRead);
+                if (RT_FAILURE(rc))
+                    break;
+                //rtHttpServerLogProto(pClient, true /* fWrite */, (const char *)pvBuf);
+                rc = rtHttpServerSendResponseBody(pClient, pvBuf, cbRead, &cbWritten);
+                AssertBreak(cbToRead >= cbWritten);
+                cbToRead -= cbWritten;
+                if (rc == VERR_NET_CONNECTION_RESET_BY_PEER) /* Clients often apruptly abort the connection when done. */
+                {
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+                AssertRCBreak(rc);
+            }
+
+            break;
+        } /* for (;;) */
+
+        RTMemFree(pvBuf);
+
+        int rc2 = rc; /* Save rc. */
+
+        RTHTTPSERVER_HANDLE_CALLBACK_VA(pfnClose, pvHandle);
+
+        if (RT_FAILURE(rc2)) /* Restore original rc on failure. */
+            rc = rc2;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+#endif /* IPRT_HTTP_WITH_WEBDAV */
+
+/**
+ * Validates if a given path is valid or not.
+ *
+ * @returns \c true if path is valid, or \c false if not.
+ * @param   pszPath             Path to check.
+ * @param   fIsAbsolute         Whether the path to check is an absolute path or not.
+ */
+static bool rtHttpServerPathIsValid(const char *pszPath, bool fIsAbsolute)
+{
+    if (!pszPath)
+        return false;
+
+    bool fIsValid =    strlen(pszPath)
+                    && RTStrIsValidEncoding(pszPath)
+                    && RTStrStr(pszPath, "..") == NULL;     /** @todo Very crude for now -- improve this. */
+    if (   fIsValid
+        && fIsAbsolute)
+    {
+        RTFSOBJINFO objInfo;
+        int rc2 = RTPathQueryInfo(pszPath, &objInfo, RTFSOBJATTRADD_NOTHING);
+        if (RT_SUCCESS(rc2))
+        {
+            fIsValid =    RTFS_IS_DIRECTORY(objInfo.Attr.fMode)
+                       || RTFS_IS_FILE(objInfo.Attr.fMode);
+
+            /* No symlinks and other stuff not allowed. */
+        }
+        else
+            fIsValid = false;
+    }
+
+    LogFlowFunc(("pszPath=%s -> %RTbool\n", pszPath, fIsValid));
+    return fIsValid;
+
+}
+
+/**
+ * Parses headers and sets (replaces) a given header list.
+ *
+ * @returns VBox status code.
+ * @param   hList               Header list to fill parsed headers in.
+ * @param   cStrings            Number of strings to parse for \a papszStrings.
+ * @param   papszStrings        Array of strings to parse.
+ */
+static int rtHttpServerParseHeaders(RTHTTPHEADERLIST hList, size_t cStrings, char **papszStrings)
+{
+    /* Nothing to parse left? Bail out early. */
+    if (   !cStrings
+        || !papszStrings)
+        return VINF_SUCCESS;
+
+#ifdef LOG_ENABLED
+    for (size_t i = 0; i < cStrings; i++)
+        LogFlowFunc(("Header: %s\n", papszStrings[i]));
+#endif
+
+    int rc = RTHttpHeaderListSet(hList, cStrings, papszStrings);
+
+    LogFlowFunc(("rc=%Rrc, cHeaders=%zu\n", rc, cStrings));
+    return rc;
+}
+
+/**
+ * Main function for parsing and allocating a client request.
+ *
+ * See: https://tools.ietf.org/html/rfc2616#section-2.2
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to parse request from.
+ * @param   pszReq              Request string with headers to parse.
+ * @param   cbReq               Size (in bytes) of request string to parse.
+ * @param   ppReq               Where to store the allocated client request on success.
+ *                              Needs to be free'd via rtHttpServerReqFree().
+ */
+static int rtHttpServerParseRequest(PRTHTTPSERVERCLIENT pClient, const char *pszReq, size_t cbReq,
+                                    PRTHTTPSERVERREQ *ppReq)
+{
+    RT_NOREF(pClient);
+
+    AssertPtrReturn(pszReq, VERR_INVALID_POINTER);
+    AssertReturn(cbReq, VERR_INVALID_PARAMETER);
+
+    /* We only support UTF-8 charset for now. */
+    AssertReturn(RTStrIsValidEncoding(pszReq), VERR_INVALID_PARAMETER);
+
+    char **ppapszReq = NULL;
+    size_t cReq      = 0;
+    int rc = RTStrSplit(pszReq, cbReq, RTHTTPSERVER_HTTP11_EOL_STR, &ppapszReq, &cReq);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    if (!cReq)
+        return VERR_INVALID_PARAMETER;
+
+#ifdef LOG_ENABLED
+    for (size_t i = 0; i < cReq; i++)
+        LogFlowFunc(("%s\n", ppapszReq[i]));
+#endif
+
+    PRTHTTPSERVERREQ pReq = NULL;
+
+    char **ppapszFirstLine = NULL;
+    size_t cFirstLine = 0;
+    rc = RTStrSplit(ppapszReq[0], strlen(ppapszReq[0]), " ", &ppapszFirstLine, &cFirstLine);
+    if (RT_SUCCESS(rc))
+    {
+        if (cFirstLine < 3) /* At leat the method, path and version has to be present. */
+            rc = VERR_INVALID_PARAMETER;
+    }
+
+    while (RT_SUCCESS(rc)) /* To use break. */
+    {
+        pReq = rtHttpServerReqAlloc();
+        AssertPtrBreakStmt(pReq, rc = VERR_NO_MEMORY);
+
+        /*
+         * Parse method to use. Method names are case sensitive.
+         */
+        const char *pszMethod = ppapszFirstLine[0];
+        if      (!RTStrCmp(pszMethod, "GET"))      pReq->enmMethod = RTHTTPMETHOD_GET;
+        else if (!RTStrCmp(pszMethod, "HEAD"))     pReq->enmMethod = RTHTTPMETHOD_HEAD;
+#ifdef IPRT_HTTP_WITH_WEBDAV
+        else if (!RTStrCmp(pszMethod, "OPTIONS"))  pReq->enmMethod = RTHTTPMETHOD_OPTIONS;
+        else if (!RTStrCmp(pszMethod, "PROPFIND")) pReq->enmMethod = RTHTTPMETHOD_PROPFIND;
+#endif
+        else
+        {
+            rc = VERR_NOT_SUPPORTED;
+            break;
+        }
+
+        /*
+         * Parse requested path.
+         */
+        /** @todo Do URL unescaping here. */
+        const char *pszPath = ppapszFirstLine[1];
+        if (!rtHttpServerPathIsValid(pszPath, false /* fIsAbsolute */))
+        {
+            rc = VERR_PATH_NOT_FOUND;
+            break;
+        }
+
+        pReq->pszUrl = RTStrDup(pszPath);
+
+        /*
+         * Parse HTTP version to use.
+         * We're picky heree: Only HTTP 1.1 is supported by now.
+         */
+        const char *pszVer = ppapszFirstLine[2];
+        if (RTStrCmp(pszVer, RTHTTPVER_1_1_STR)) /** @todo Use RTStrVersionCompare. Later. */
+        {
+            rc = VERR_NOT_SUPPORTED;
+            break;
+        }
+
+        /** @todo Anything else needed for the first line here? */
+
+        /*
+         * Process headers, if any.
+         */
+        if (cReq > 1)
+        {
+            rc = rtHttpServerParseHeaders(pReq->hHdrLst, cReq - 1, &ppapszReq[1]);
+            if (RT_SUCCESS(rc))
+            {
+                if (RTHttpHeaderListGet(pReq->hHdrLst, "Connection", RTSTR_MAX))
+                    pClient->State.msKeepAlive = RT_MS_30SEC; /** @todo Insert the real value here. */
+            }
+        }
+        break;
+    } /* for (;;) */
+
+    /*
+     * Cleanup.
+     */
+
+    for (size_t i = 0; i < cFirstLine; i++)
+        RTStrFree(ppapszFirstLine[i]);
+    RTMemFree(ppapszFirstLine);
+
+    for (size_t i = 0; i < cReq; i++)
+        RTStrFree(ppapszReq[i]);
+    RTMemFree(ppapszReq);
+
+    if (RT_FAILURE(rc))
+    {
+        rtHttpServerReqFree(pReq);
+        pReq = NULL;
+    }
+    else
+        *ppReq = pReq;
+
+    return rc;
+}
+
+/**
+ * Main function for processing client requests.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to process request for.
+ * @param   pszReq              Request string to parse and handle.
+ * @param   cbReq               Size (in bytes) of request string.
+ */
+static int rtHttpServerProcessRequest(PRTHTTPSERVERCLIENT pClient, char *pszReq, size_t cbReq)
+{
+    RTHTTPSTATUS enmSts = RTHTTPSTATUS_INTERNAL_NOT_SET;
+
+    PRTHTTPSERVERREQ pReq = NULL; /* Shut up GCC. */
+    int rc = rtHttpServerParseRequest(pClient, pszReq, cbReq, &pReq);
+    if (RT_SUCCESS(rc))
+    {
+        LogFlowFunc(("Request %s %s\n", RTHttpMethodToStr(pReq->enmMethod), pReq->pszUrl));
+
+        unsigned i = 0;
+        for (; i < RT_ELEMENTS(g_aMethodMap); i++)
+        {
+            const RTHTTPSERVERMETHOD_ENTRY *pMethodEntry = &g_aMethodMap[i];
+            if (pReq->enmMethod == pMethodEntry->enmMethod)
+            {
+                /* Hand in request to method handler. */
+                int rcMethod = pMethodEntry->pfnMethod(pClient, pReq);
+                if (RT_FAILURE(rcMethod))
+                    LogFunc(("Request %s %s failed with %Rrc\n", RTHttpMethodToStr(pReq->enmMethod), pReq->pszUrl, rcMethod));
+
+                enmSts = rtHttpServerRcToStatus(rcMethod);
+                break;
+            }
+        }
+
+        if (i == RT_ELEMENTS(g_aMethodMap))
+            enmSts = RTHTTPSTATUS_NOTIMPLEMENTED;
+
+        rtHttpServerReqFree(pReq);
+    }
+    else
+        enmSts = RTHTTPSTATUS_BADREQUEST;
+
+    if (enmSts != RTHTTPSTATUS_INTERNAL_NOT_SET)
+    {
+        int rc2 = rtHttpServerSendResponseSimple(pClient, enmSts);
+        if (RT_SUCCESS(rc))
+            rc = rc2;
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Main loop for processing client requests.
+ *
+ * @returns VBox status code.
+ * @param   pClient             Client to process requests for.
+ */
+static int rtHttpServerClientMain(PRTHTTPSERVERCLIENT pClient)
+{
+    int rc;
+
+    char szReq[RTHTTPSERVER_MAX_REQ_LEN + 1];
+
+    LogFlowFunc(("Client connected\n"));
+
+    /* Initialize client state. */
+    pClient->State.msKeepAlive = 0;
+
+    RTMSINTERVAL cWaitMs      = RT_INDEFINITE_WAIT; /* The first wait always waits indefinitely. */
+    uint64_t     tsLastReadMs = 0;
+
+    for (;;)
+    {
+        rc = RTTcpSelectOne(pClient->hSocket, cWaitMs);
+        if (RT_FAILURE(rc))
+        {
+            LogFlowFunc(("RTTcpSelectOne=%Rrc (cWaitMs=%RU64)\n", rc, cWaitMs));
+            if (rc == VERR_TIMEOUT)
+            {
+                if (pClient->State.msKeepAlive) /* Keep alive handling needed? */
+                {
+                    if (!tsLastReadMs)
+                        tsLastReadMs = RTTimeMilliTS();
+                    const uint64_t tsDeltaMs = pClient->State.msKeepAlive - (RTTimeMilliTS() - tsLastReadMs);
+                    LogFlowFunc(("tsLastReadMs=%RU64, tsDeltaMs=%RU64\n", tsLastReadMs, tsDeltaMs));
+                    Log3Func(("Keep alive active (%RU32ms): %RU64ms remaining\n", pClient->State.msKeepAlive, tsDeltaMs));
+                    if (   tsDeltaMs > cWaitMs
+                        && tsDeltaMs < pClient->State.msKeepAlive)
+                        continue;
+
+                    LogFunc(("Keep alive active: Client did not respond within %RU32ms, closing\n", pClient->State.msKeepAlive));
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+            }
+
+            break;
+        }
+
+        LogFlowFunc(("Reading client request ...\n"));
+
+        tsLastReadMs = RTTimeMilliTS();
+        cWaitMs      = 200;  /* All consequtive waits do busy waiting for now. */
+
+        char  *pszReq      = szReq;
+        size_t cbRead;
+        size_t cbToRead    = sizeof(szReq);
+        size_t cbReadTotal = 0;
+
+        do
+        {
+            rc = RTTcpReadNB(pClient->hSocket, pszReq, cbToRead, &cbRead);
+            if (RT_FAILURE(rc))
+                break;
+
+            if (!cbRead)
+                break;
+
+            /* Make sure to terminate string read so far. */
+            pszReq[cbRead] = '\0';
+
+            /* End of request reached? */
+            /** @todo BUGBUG Improve this. */
+            char *pszEOR = RTStrStr(&pszReq[cbReadTotal], "\r\n\r\n");
+            if (pszEOR)
+            {
+                cbReadTotal = pszEOR - pszReq;
+                *pszEOR = '\0';
+                break;
+            }
+
+            AssertBreak(cbToRead >= cbRead);
+            cbToRead    -= cbRead;
+            cbReadTotal += cbRead;
+            AssertBreak(cbReadTotal <= sizeof(szReq));
+            pszReq      += cbRead;
+
+        } while (cbToRead);
+
+        if (   RT_SUCCESS(rc)
+            && cbReadTotal)
+        {
+            LogFlowFunc(("Received client request (%zu bytes)\n", cbReadTotal));
+
+            rtHttpServerLogProto(pClient, false /* fWrite */, szReq);
+
+            rc = rtHttpServerProcessRequest(pClient, szReq, cbReadTotal);
+        }
+        else
+            break;
+
+    } /* for */
+
+    if (RT_FAILURE(rc))
+    {
+        switch (rc)
+        {
+            case VERR_NET_CONNECTION_RESET_BY_PEER:
+            {
+                LogFunc(("Client closed the connection\n"));
+                rc = VINF_SUCCESS;
+                break;
+            }
+
+            default:
+                LogFunc(("Client processing failed with %Rrc\n", rc));
+                break;
+        }
+    }
+
+    LogFlowFuncLeaveRC(rc);
+    return rc;
+}
+
+/**
+ * Per-client thread for serving the server's control connection.
+ *
+ * @returns VBox status code.
+ * @param   hSocket             Socket handle to use for the control connection.
+ * @param   pvUser              User-provided arguments. Of type PRTHTTPSERVERINTERNAL.
+ */
+static DECLCALLBACK(int) rtHttpServerClientThread(RTSOCKET hSocket, void *pvUser)
+{
+    PRTHTTPSERVERINTERNAL pThis = (PRTHTTPSERVERINTERNAL)pvUser;
+    RTHTTPSERVER_VALID_RETURN(pThis);
+
+    LogFlowFuncEnter();
+
+    RTHTTPSERVERCLIENT Client;
+    RT_ZERO(Client);
+
+    Client.pServer = pThis;
+    Client.hSocket = hSocket;
+
+    return rtHttpServerClientMain(&Client);
+}
+
+RTR3DECL(int) RTHttpServerCreate(PRTHTTPSERVER hHttpServer, const char *pszAddress, uint16_t uPort,
+                                 PRTHTTPSERVERCALLBACKS pCallbacks, void *pvUser, size_t cbUser)
+{
+    AssertPtrReturn(hHttpServer, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszAddress,  VERR_INVALID_POINTER);
+    AssertReturn   (uPort,       VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pCallbacks,  VERR_INVALID_POINTER);
+    /* pvUser is optional. */
+
+    int rc;
+
+    PRTHTTPSERVERINTERNAL pThis = (PRTHTTPSERVERINTERNAL)RTMemAllocZ(sizeof(RTHTTPSERVERINTERNAL));
+    if (pThis)
+    {
+        pThis->u32Magic  = RTHTTPSERVER_MAGIC;
+        pThis->Callbacks = *pCallbacks;
+        pThis->pvUser    = pvUser;
+        pThis->cbUser    = cbUser;
+
+        rc = RTTcpServerCreate(pszAddress, uPort, RTTHREADTYPE_DEFAULT, "httpsrv",
+                               rtHttpServerClientThread, pThis /* pvUser */, &pThis->pTCPServer);
+        if (RT_SUCCESS(rc))
+        {
+            *hHttpServer = (RTHTTPSERVER)pThis;
+        }
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+RTR3DECL(int) RTHttpServerDestroy(RTHTTPSERVER hHttpServer)
+{
+    if (hHttpServer == NIL_RTHTTPSERVER)
+        return VINF_SUCCESS;
+
+    PRTHTTPSERVERINTERNAL pThis = hHttpServer;
+    RTHTTPSERVER_VALID_RETURN(pThis);
+
+    AssertPtr(pThis->pTCPServer);
+
+    int rc = VINF_SUCCESS;
+
+    PRTHTTPSERVERCALLBACKS pCallbacks = &pThis->Callbacks;
+    if (pCallbacks->pfnDestroy)
+    {
+        RTHTTPCALLBACKDATA Data = { NULL /* pClient */, pThis->pvUser, pThis->cbUser };
+        rc = pCallbacks->pfnDestroy(&Data);
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTTcpServerDestroy(pThis->pTCPServer);
+        if (RT_SUCCESS(rc))
+        {
+            pThis->u32Magic = RTHTTPSERVER_MAGIC_DEAD;
+
+            RTMemFree(pThis);
+        }
+    }
+
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/init-data.cpp b/src/VBox/Runtime/r3/init-data.cpp
new file mode 100644
index 00000000..8cc2cb09
--- /dev/null
+++ b/src/VBox/Runtime/r3/init-data.cpp
@@ -0,0 +1,63 @@
+/* $Id: init-data.cpp $ */
+/** @file
+ * IPRT - Init Data Ring-3.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include "internal/initterm.h"
+#include "internal/time.h"      /* g_u64ProgramStartNanoTS */
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The number of calls to RTR3Init*. */
+DECL_HIDDEN_DATA(int32_t volatile)  g_crtR3Users        = 0;
+/** Whether we're currently initializing the IPRT. */
+DECL_HIDDEN_DATA(bool volatile)     g_frtR3Initializing = false;
+/**
+ * Set if the atexit callback has been called, i.e. indicating
+ * that the process is terminating.
+ */
+DECL_HIDDEN_DATA(bool volatile)     g_frtAtExitCalled   = false;
+
+/**
+ * Program start nanosecond TS.
+ */
+DECL_HIDDEN_DATA(uint64_t)          g_u64ProgramStartNanoTS = 0;
+
diff --git a/src/VBox/Runtime/r3/init.cpp b/src/VBox/Runtime/r3/init.cpp
new file mode 100644
index 00000000..e10ba6b4
--- /dev/null
+++ b/src/VBox/Runtime/r3/init.cpp
@@ -0,0 +1,666 @@
+/* $Id: init.cpp $ */
+/** @file
+ * IPRT - Init Ring-3.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/types.h>                 /* darwin: UINT32_C and others. */
+
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/windows.h>
+#else
+# include <unistd.h>
+# ifndef RT_OS_OS2
+#  include <pthread.h>
+#  include <signal.h>
+#  include <errno.h>
+#  define IPRT_USE_SIG_CHILD_DUMMY
+# endif
+#endif
+#ifdef RT_OS_OS2
+# include <InnoTekLIBC/fork.h>
+# define INCL_DOSMISC
+# include <os2.h>
+#endif
+#ifndef IPRT_NO_CRT
+# include <locale.h>
+#endif
+
+#include <iprt/initterm.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/env.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/path.h>
+#include <iprt/time.h>
+#include <iprt/string.h>
+#include <iprt/param.h>
+#ifdef RT_OS_WINDOWS
+# include <iprt/getopt.h>
+# include <iprt/utf16.h>
+#endif
+#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
+# include <iprt/file.h>
+# include <VBox/sup.h>
+#endif
+#include <stdlib.h>
+
+#include "init.h"
+#include "internal/alignmentchecks.h"
+#include "internal/initterm.h"
+#include "internal/path.h"
+#include "internal/process.h"
+#include "internal/thread.h"
+#include "internal/time.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The IPRT init flags. */
+static uint32_t             g_fInitFlags;
+
+/** The argument count of the program.  */
+static int                  g_crtArgs = -1;
+/** The arguments of the program (UTF-8).  This is "leaked". */
+static char **              g_papszrtArgs;
+/** The original argument vector of the program. */
+static char **              g_papszrtOrgArgs;
+
+#ifdef IPRT_WITH_ALIGNMENT_CHECKS
+/**
+ * Whether alignment checks are enabled.
+ * This is set if the environment variable IPRT_ALIGNMENT_CHECKS is 1.
+ */
+RTDATADECL(bool) g_fRTAlignmentChecks = false;
+#endif
+
+
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD) || defined(RT_OS_NETBSD) || defined(RT_OS_HAIKU) \
+ || defined(RT_OS_LINUX)  || defined(RT_OS_OS2)     || defined(RT_OS_SOLARIS) /** @todo add host init hooks everywhere. */
+/* Stubs */
+DECLHIDDEN(int)  rtR3InitNativeFirst(uint32_t fFlags)     { RT_NOREF_PV(fFlags); return VINF_SUCCESS; }
+DECLHIDDEN(int)  rtR3InitNativeFinal(uint32_t fFlags)     { RT_NOREF_PV(fFlags); return VINF_SUCCESS; }
+DECLHIDDEN(void) rtR3InitNativeObtrusive(uint32_t fFlags) { RT_NOREF_PV(fFlags); }
+#endif
+
+
+/**
+ * atexit callback.
+ *
+ * This makes sure any loggers are flushed and will later also work the
+ * termination callback chain.
+ */
+static void rtR3ExitCallback(void) RT_NOTHROW_DEF
+{
+    ASMAtomicWriteBool(&g_frtAtExitCalled, true);
+
+    if (g_crtR3Users > 0)
+    {
+        PRTLOGGER pLogger = RTLogGetDefaultInstance();
+        if (pLogger)
+            RTLogFlush(pLogger);
+
+        pLogger = RTLogRelGetDefaultInstance();
+        if (pLogger)
+            RTLogFlush(pLogger);
+    }
+}
+
+
+#ifndef RT_OS_WINDOWS
+/**
+ * Fork callback, child context.
+ */
+static void rtR3ForkChildCallback(void)
+{
+    g_ProcessSelf = getpid();
+}
+#endif /* RT_OS_WINDOWS */
+
+#ifdef RT_OS_OS2
+/** Fork completion callback for OS/2.  Only called in the child. */
+static void rtR3ForkOs2ChildCompletionCallback(void *pvArg, int rc, __LIBC_FORKCTX enmCtx)
+{
+    Assert(enmCtx == __LIBC_FORK_CTX_CHILD); NOREF(enmCtx);
+    NOREF(pvArg);
+
+    if (!rc)
+        rtR3ForkChildCallback();
+}
+
+/** Low-level fork callback for OS/2.  */
+int rtR3ForkOs2Child(__LIBC_PFORKHANDLE pForkHandle, __LIBC_FORKOP enmOperation)
+{
+    if (enmOperation == __LIBC_FORK_OP_EXEC_CHILD)
+        return pForkHandle->pfnCompletionCallback(pForkHandle, rtR3ForkOs2ChildCompletionCallback, NULL, __LIBC_FORK_CTX_CHILD);
+    return 0;
+}
+
+# define static static volatile /** @todo _FORK_CHILD1 causes unresolved externals in optimized builds. Fix macro. */
+_FORK_CHILD1(0, rtR3ForkOs2Child);
+# undef static
+#endif /* RT_OS_OS2 */
+
+
+
+/**
+ * Internal worker which initializes or re-initializes the
+ * program path, name and directory globals.
+ *
+ * @returns IPRT status code.
+ * @param   pszProgramPath  The program path, NULL if not specified.
+ */
+static int rtR3InitProgramPath(const char *pszProgramPath)
+{
+    /*
+     * We're reserving 32 bytes here for file names as what not.
+     */
+    if (!pszProgramPath)
+    {
+        int rc = rtProcInitExePath(g_szrtProcExePath, sizeof(g_szrtProcExePath) - 32);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+    else
+    {
+        size_t cch = strlen(pszProgramPath);
+        Assert(cch > 1);
+        AssertMsgReturn(cch < sizeof(g_szrtProcExePath) - 32, ("%zu\n", cch), VERR_BUFFER_OVERFLOW);
+        memcpy(g_szrtProcExePath, pszProgramPath, cch + 1);
+    }
+
+    /*
+     * Parse the name.
+     */
+    ssize_t offName;
+    g_cchrtProcExePath = RTPathParseSimple(g_szrtProcExePath, &g_cchrtProcExeDir, &offName, NULL);
+    g_offrtProcName = offName;
+    return VINF_SUCCESS;
+}
+
+
+#ifdef RT_OS_WINDOWS
+/**
+ * Checks the two argument vectors contains the same strings.
+ */
+DECLINLINE(bool) rtR3InitArgvEquals(int cArgs, char **papszArgs1, char **papszArgs2)
+{
+    if (papszArgs1 != papszArgs2)
+        while (cArgs-- > 0)
+            if (strcmp(papszArgs1[cArgs], papszArgs2[cArgs]) != 0)
+                return false;
+    return true;
+}
+#endif
+
+
+/**
+ * Internal worker which initializes or re-initializes the
+ * program path, name and directory globals.
+ *
+ * @returns IPRT status code.
+ * @param   fFlags          Flags, see RTR3INIT_XXX.
+ * @param   cArgs           Pointer to the argument count.
+ * @param   ppapszArgs      Pointer to the argument vector pointer. NULL
+ *                          allowed if @a cArgs is 0.
+ */
+static int rtR3InitArgv(uint32_t fFlags, int cArgs, char ***ppapszArgs)
+{
+    NOREF(fFlags);
+    if (cArgs)
+    {
+        AssertPtr(ppapszArgs);
+        AssertPtr(*ppapszArgs);
+        char **papszOrgArgs = *ppapszArgs;
+
+        /*
+         * Normally we should only be asked to convert arguments once.  If we
+         * are though, it should be the already convered arguments.
+         */
+        if (g_crtArgs != -1)
+        {
+            AssertReturn(   g_crtArgs == cArgs
+                         && g_papszrtArgs == papszOrgArgs,
+                         VERR_WRONG_ORDER); /* only init once! */
+            return VINF_SUCCESS;
+        }
+
+#if !defined(IPRT_NO_CRT) || !defined(RT_OS_WINDOWS)
+        if (!(fFlags & RTR3INIT_FLAGS_UTF8_ARGV))
+        {
+            /*
+             * Convert the arguments.
+             */
+            char **papszArgs;
+
+# ifdef RT_OS_WINDOWS
+            /* HACK ALERT! Try convert from unicode versions if possible.
+               Unfortunately for us, __wargv is only initialized if we have a unicode
+               main function.  So, use getoptarv.cpp code to do the conversions and
+               hope it gives us the same result. (CommandLineToArgvW was not in NT 3.1.) */
+            if (   cArgs == __argc
+                && rtR3InitArgvEquals(cArgs, papszOrgArgs, __argv))
+            {
+                char *pszCmdLine = NULL;
+                int rc = RTUtf16ToUtf8Tag(GetCommandLineW(), &pszCmdLine, "will-leak:rtR3InitArgv");
+                AssertRCReturn(rc, rc);
+
+                int cArgsFromCmdLine = -1;
+                rc = RTGetOptArgvFromString(&papszArgs, &cArgsFromCmdLine, pszCmdLine,
+                                            RTGETOPTARGV_CNV_QUOTE_MS_CRT | RTGETOPTARGV_CNV_MODIFY_INPUT, NULL);
+                AssertMsgRCReturn(rc, ("pszCmdLine='%s' rc=%Rrc\n", pszCmdLine, rc), rc);
+                AssertMsg(cArgsFromCmdLine == cArgs,
+                          ("cArgsFromCmdLine=%d cArgs=%d pszCmdLine='%s' rc=%Rrc\n", cArgsFromCmdLine, cArgs, pszCmdLine));
+            }
+            else
+# endif
+            {
+                papszArgs = (char **)RTMemAllocZTag((cArgs + 1) * sizeof(char *), "will-leak:rtR3InitArgv");
+                if (!papszArgs)
+                    return VERR_NO_MEMORY;
+
+                for (int i = 0; i < cArgs; i++)
+                {
+                    int rc = RTStrCurrentCPToUtf8(&papszArgs[i], papszOrgArgs[i]);
+                    if (RT_FAILURE(rc))
+                    {
+                        while (i--)
+                            RTStrFree(papszArgs[i]);
+                        RTMemFree(papszArgs);
+                        return rc;
+                    }
+                }
+            }
+
+            papszArgs[cArgs] = NULL;
+
+            g_papszrtOrgArgs = papszOrgArgs;
+            g_papszrtArgs    = papszArgs;
+            g_crtArgs        = cArgs;
+
+            *ppapszArgs = papszArgs;
+        }
+        else
+#endif /* !IPRT_NO_CRT || !RT_OS_WINDOWS */
+        {
+            /*
+             * The arguments are already UTF-8, no conversion needed.
+             */
+            g_papszrtOrgArgs = papszOrgArgs;
+            g_papszrtArgs    = papszOrgArgs;
+            g_crtArgs        = cArgs;
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+#ifdef IPRT_USE_SIG_CHILD_DUMMY
+/**
+ * Dummy SIGCHILD handler.
+ *
+ * Assigned on rtR3Init only when SIGCHILD handler is set SIGIGN or SIGDEF to
+ * ensure waitpid works properly for the terminated processes.
+ */
+static void rtR3SigChildHandler(int iSignal)
+{
+    NOREF(iSignal);
+}
+#endif /* IPRT_USE_SIG_CHILD_DUMMY */
+
+
+/**
+ * rtR3Init worker.
+ */
+static int rtR3InitBody(uint32_t fFlags, int cArgs, char ***ppapszArgs, const char *pszProgramPath)
+{
+    /*
+     * Early native initialization.
+     */
+    int rc = rtR3InitNativeFirst(fFlags);
+    AssertMsgRCReturn(rc, ("rtR3InitNativeFirst failed with %Rrc\n", rc), rc);
+
+    /*
+     * Disable error popups.
+     */
+#if defined(RT_OS_OS2) /** @todo move to private code. */
+    DosError(FERR_DISABLEHARDERR);
+#endif
+
+#ifndef IPRT_NO_CRT
+    /*
+     * Init C runtime locale before we do anything that may end up converting
+     * paths or we'll end up using the "C" locale for path conversion.
+     */
+    setlocale(LC_CTYPE, "");
+#endif
+
+    /*
+     * The Process ID.
+     */
+#ifdef _MSC_VER
+    g_ProcessSelf = GetCurrentProcessId(); /* since NT 3.1, not 3.51+ as listed on geoffchappell.com */
+#else
+    g_ProcessSelf = getpid();
+#endif
+
+    /*
+     * Save the init flags.
+     */
+    g_fInitFlags |= fFlags;
+
+#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
+# ifdef VBOX
+    /*
+     * This MUST be done as the very first thing, before any file is opened.
+     * The log is opened on demand, but the first log entries may be caused
+     * by rtThreadInit() below.
+     */
+    const char *pszDisableHostCache = getenv("VBOX_DISABLE_HOST_DISK_CACHE");
+    if (    pszDisableHostCache != NULL
+        &&  *pszDisableHostCache
+        &&  strcmp(pszDisableHostCache, "0") != 0)
+    {
+        RTFileSetForceFlags(RTFILE_O_WRITE, RTFILE_O_WRITE_THROUGH, 0);
+        RTFileSetForceFlags(RTFILE_O_READWRITE, RTFILE_O_WRITE_THROUGH, 0);
+    }
+# endif  /* VBOX */
+#endif /* !IN_GUEST && !RT_NO_GIP */
+
+    /*
+     * Thread Thread database and adopt the caller thread as 'main'.
+     * This must be done before everything else or else we'll call into threading
+     * without having initialized TLS entries and suchlike.
+     */
+    rc = rtThreadInit();
+    AssertMsgRCReturn(rc, ("Failed to initialize threads, rc=%Rrc!\n", rc), rc);
+
+    /*
+     * The executable path before SUPLib (windows requirement).
+     */
+    rc = rtR3InitProgramPath(pszProgramPath);
+    AssertLogRelMsgRCReturn(rc, ("Failed to get executable directory path, rc=%Rrc!\n", rc), rc);
+
+#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
+    /*
+     * Initialize SUPLib here so the GIP can get going as early as possible
+     * (improves accuracy for the first client).
+     */
+    if (fFlags & (RTR3INIT_FLAGS_SUPLIB | RTR3INIT_FLAGS_TRY_SUPLIB))
+    {
+        if (!(fFlags & ((SUPR3INIT_F_UNRESTRICTED | SUPR3INIT_F_LIMITED) << RTR3INIT_FLAGS_SUPLIB_SHIFT)))
+            g_fInitFlags |= fFlags |= SUPR3INIT_F_UNRESTRICTED << RTR3INIT_FLAGS_SUPLIB_SHIFT;
+        rc = SUPR3InitEx(fFlags >> RTR3INIT_FLAGS_SUPLIB_SHIFT, NULL /*ppSession*/);
+        AssertMsgReturn(RT_SUCCESS(rc) || (fFlags & RTR3INIT_FLAGS_TRY_SUPLIB),
+                        ("Failed to initialize the support library, rc=%Rrc!\n", rc), rc);
+    }
+#endif
+
+    /*
+     * Convert arguments.
+     */
+    rc = rtR3InitArgv(fFlags, cArgs, ppapszArgs);
+    AssertLogRelMsgRCReturn(rc, ("Failed to convert the arguments, rc=%Rrc!\n", rc), rc);
+
+#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
+    /*
+     * The threading is initialized, so we can safely sleep a bit if GIP
+     * needs some time to start updating itself.  Currently limited to
+     * the first mapping of GIP (u32TransactionId <= 4), quite possible we
+     * could just ditch this now.
+     */
+    /** @todo consider dropping this... */
+    PSUPGLOBALINFOPAGE pGip;
+    if (   (fFlags & (RTR3INIT_FLAGS_SUPLIB | RTR3INIT_FLAGS_TRY_SUPLIB))
+        && (pGip = g_pSUPGlobalInfoPage) != NULL
+        && pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC)
+    {
+        PSUPGIPCPU pGipCpu = SUPGetGipCpuPtr(pGip);
+        if (   pGipCpu
+            && pGipCpu->u32TransactionId <= 4)
+        {
+            RTThreadSleep(pGip->u32UpdateIntervalNS / RT_NS_1MS + 2);
+            RTTimeNanoTS();
+        }
+    }
+#endif
+
+    /*
+     * Init the program start timestamp TS.
+     * Do that here to be sure that the GIP time was properly updated the 1st time.
+     */
+    g_u64ProgramStartNanoTS = RTTimeNanoTS();
+
+    /*
+     * The remainder cannot easily be undone, so it has to go last.
+     */
+
+    /* Fork and exit callbacks. */
+#if !defined(RT_OS_WINDOWS) && !defined(RT_OS_OS2)
+    rc = pthread_atfork(NULL, NULL, rtR3ForkChildCallback);
+    AssertMsg(rc == 0, ("%d\n", rc));
+#endif
+    atexit(rtR3ExitCallback);
+
+#ifdef IPRT_USE_SIG_CHILD_DUMMY
+    /*
+     * SIGCHLD must not be ignored (that's default), otherwise posix compliant waitpid
+     * implementations won't work right.
+     */
+    for (;;)
+    {
+        struct sigaction saOld;
+        rc = sigaction(SIGCHLD, 0, &saOld);         AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
+        if (    rc != 0
+            ||  (saOld.sa_flags & SA_SIGINFO)
+            || (   saOld.sa_handler != SIG_IGN
+                && saOld.sa_handler != SIG_DFL)
+           )
+            break;
+
+        /* Try install dummy handler. */
+        struct sigaction saNew = saOld;
+        saNew.sa_flags   = SA_NOCLDSTOP | SA_RESTART;
+        saNew.sa_handler = rtR3SigChildHandler;
+        rc = sigemptyset(&saNew.sa_mask);           AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
+        struct sigaction saOld2;
+        rc = sigaction(SIGCHLD, &saNew, &saOld2);   AssertMsg(rc == 0, ("%d/%d\n", rc, errno));
+        if (    rc != 0
+            ||  (   saOld2.sa_handler == saOld.sa_handler
+                 && !(saOld2.sa_flags & SA_SIGINFO))
+           )
+            break;
+
+        /* Race during dynamic load, restore and try again... */
+        sigaction(SIGCHLD, &saOld2, NULL);
+        RTThreadYield();
+    }
+#endif /* IPRT_USE_SIG_CHILD_DUMMY */
+
+#ifdef IPRT_WITH_ALIGNMENT_CHECKS
+    /*
+     * Enable alignment checks.
+     */
+    const char *pszAlignmentChecks = RTEnvGet("IPRT_ALIGNMENT_CHECKS"); /** @todo add RTEnvGetBool */
+    g_fRTAlignmentChecks = pszAlignmentChecks != NULL
+                        && pszAlignmentChecks[0] == '1'
+                        && pszAlignmentChecks[1] == '\0';
+    if (g_fRTAlignmentChecks)
+        IPRT_ALIGNMENT_CHECKS_ENABLE();
+#endif
+
+    /*
+     * Final native initialization.
+     */
+    rc = rtR3InitNativeFinal(fFlags);
+    AssertMsgRCReturn(rc, ("rtR3InitNativeFinal failed with %Rrc\n", rc), rc);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Internal initialization worker.
+ *
+ * @returns IPRT status code.
+ * @param   fFlags          Flags, see RTR3INIT_XXX.
+ * @param   cArgs           Pointer to the argument count.
+ * @param   ppapszArgs      Pointer to the argument vector pointer. NULL
+ *                          allowed if @a cArgs is 0.
+ * @param   pszProgramPath  The program path.  Pass NULL if we're to figure it
+ *                          out ourselves.
+ */
+static int rtR3Init(uint32_t fFlags, int cArgs, char ***ppapszArgs, const char *pszProgramPath)
+{
+    /* no entry log flow, because prefixes and thread may freak out. */
+    Assert(!(fFlags & ~RTR3INIT_FLAGS_VALID_MASK));
+    Assert(!(fFlags & RTR3INIT_FLAGS_DLL) || cArgs == 0);
+
+    /*
+     * Do reference counting, only initialize the first time around.
+     *
+     * We are ASSUMING that nobody will be able to race RTR3Init* calls when the
+     * first one, the real init, is running (second assertion).
+     */
+    int32_t cUsers = ASMAtomicIncS32(&g_crtR3Users);
+    if (cUsers != 1)
+    {
+        AssertMsg(cUsers > 1, ("%d\n", cUsers));
+        Assert(!g_frtR3Initializing);
+
+#if !defined(IN_GUEST) && !defined(RT_NO_GIP)
+        /* Initialize the support library if requested. We've always ignored the
+           status code here for some reason, making the two flags same. */
+        if (fFlags & (RTR3INIT_FLAGS_SUPLIB | RTR3INIT_FLAGS_TRY_SUPLIB))
+        {
+            if (!(fFlags & ((SUPR3INIT_F_UNRESTRICTED | SUPR3INIT_F_LIMITED) << RTR3INIT_FLAGS_SUPLIB_SHIFT)))
+                fFlags |= SUPR3INIT_F_UNRESTRICTED << RTR3INIT_FLAGS_SUPLIB_SHIFT;
+            SUPR3InitEx(fFlags >> RTR3INIT_FLAGS_SUPLIB_SHIFT, NULL /*ppSession*/);
+            g_fInitFlags |= fFlags & (RTR3INIT_FLAGS_SUPLIB | RTR3INIT_FLAGS_TRY_SUPLIB | RTR3INIT_FLAGS_SUPLIB_MASK);
+        }
+#endif
+        g_fInitFlags |= fFlags & RTR3INIT_FLAGS_UTF8_ARGV;
+
+        if (   !(fFlags      & RTR3INIT_FLAGS_UNOBTRUSIVE)
+            && (g_fInitFlags & RTR3INIT_FLAGS_UNOBTRUSIVE))
+        {
+            g_fInitFlags &= ~RTR3INIT_FLAGS_UNOBTRUSIVE;
+            g_fInitFlags |= fFlags & RTR3INIT_FLAGS_STANDALONE_APP;
+            rtR3InitNativeObtrusive(g_fInitFlags | fFlags);
+            rtThreadReInitObtrusive();
+        }
+        else
+            Assert(!(fFlags & RTR3INIT_FLAGS_STANDALONE_APP) || (g_fInitFlags & RTR3INIT_FLAGS_STANDALONE_APP));
+
+        int rc = VINF_SUCCESS;
+        if (pszProgramPath)
+            rc = rtR3InitProgramPath(pszProgramPath);
+        if (RT_SUCCESS(rc))
+            rc = rtR3InitArgv(fFlags, cArgs, ppapszArgs);
+        return rc;
+    }
+
+    /*
+     * Do the initialization.
+     */
+    ASMAtomicWriteBool(&g_frtR3Initializing, true);
+    int rc = rtR3InitBody(fFlags, cArgs, ppapszArgs, pszProgramPath);
+    ASMAtomicWriteBool(&g_frtR3Initializing, false);
+    if (RT_FAILURE(rc))
+    {
+        /* failure */
+        ASMAtomicDecS32(&g_crtR3Users);
+        return rc;
+    }
+
+    /* success */
+    LogFlow(("rtR3Init: returns VINF_SUCCESS\n"));
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTR3InitExe(int cArgs, char ***ppapszArgs, uint32_t fFlags)
+{
+    Assert(!(fFlags & RTR3INIT_FLAGS_DLL));
+    return rtR3Init(fFlags, cArgs, ppapszArgs, NULL);
+}
+
+
+RTR3DECL(int) RTR3InitExeNoArguments(uint32_t fFlags)
+{
+    Assert(!(fFlags & RTR3INIT_FLAGS_DLL));
+    return rtR3Init(fFlags, 0, NULL, NULL);
+}
+
+
+RTR3DECL(int) RTR3InitDll(uint32_t fFlags)
+{
+    Assert(!(fFlags & RTR3INIT_FLAGS_DLL));
+    return rtR3Init(fFlags | RTR3INIT_FLAGS_DLL, 0, NULL, NULL);
+}
+
+
+RTR3DECL(int) RTR3InitEx(uint32_t iVersion, uint32_t fFlags, int cArgs, char ***ppapszArgs, const char *pszProgramPath)
+{
+    AssertReturn(iVersion == RTR3INIT_VER_CUR, VERR_NOT_SUPPORTED);
+    return rtR3Init(fFlags, cArgs, ppapszArgs, pszProgramPath);
+}
+
+
+RTR3DECL(bool) RTR3InitIsInitialized(void)
+{
+    return g_crtR3Users >= 1 && !g_frtR3Initializing;
+}
+
+
+RTR3DECL(bool) RTR3InitIsUnobtrusive(void)
+{
+    return RT_BOOL(g_fInitFlags & RTR3INIT_FLAGS_UNOBTRUSIVE);
+}
+
+
+#if 0 /** @todo implement RTR3Term. */
+RTR3DECL(void) RTR3Term(void)
+{
+}
+#endif
+
diff --git a/src/VBox/Runtime/r3/init.h b/src/VBox/Runtime/r3/init.h
new file mode 100644
index 00000000..95d7e52c
--- /dev/null
+++ b/src/VBox/Runtime/r3/init.h
@@ -0,0 +1,50 @@
+/* $Id: init.h $ */
+/** @file
+ * IPRT - Ring-3 initialization.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_init_h
+#define IPRT_INCLUDED_SRC_r3_init_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#include <iprt/types.h>
+
+DECLHIDDEN(int)  rtR3InitNativeFirst(uint32_t fFlags);
+DECLHIDDEN(int)  rtR3InitNativeFinal(uint32_t fFlags);
+DECLHIDDEN(void) rtR3InitNativeObtrusive(uint32_t fFlags);
+
+#endif /* !IPRT_INCLUDED_SRC_r3_init_h */
+
diff --git a/src/VBox/Runtime/r3/linux/Makefile.kup b/src/VBox/Runtime/r3/linux/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/Makefile.kup
diff --git a/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp b/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp
new file mode 100644
index 00000000..0b1d93d7
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTFileCopyPartEx-linux.cpp
@@ -0,0 +1,196 @@
+/* $Id: RTFileCopyPartEx-linux.cpp $ */
+/** @file
+ * IPRT - RTFileCopyPartEx, linux specific implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/file.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#ifndef __NR_copy_file_range
+# if defined(RT_ARCH_X86)
+#  define __NR_copy_file_range      377
+# elif defined(RT_ARCH_AMD64)
+#  define __NR_copy_file_range      326
+# endif
+#endif
+
+
+#ifndef __NR_copy_file_range
+# include "../../generic/RTFileCopyPartEx-generic.cpp"
+#else  /* __NR_copy_file_range - whole file */
+/* Include the generic code as a fallback since copy_file_range is rather new . */
+# define IPRT_FALLBACK_VERSION
+# include "../../generic/RTFileCopyPartEx-generic.cpp"
+# undef  IPRT_FALLBACK_VERSION
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static int32_t volatile g_fCopyFileRangeSupported = -1;
+
+
+DECLINLINE(loff_t)
+MyCopyFileRangeSysCall(int fdIn, loff_t *poffIn, int fdOut, loff_t *poffOut, size_t cbChunk, unsigned int fFlags)
+{
+    return syscall(__NR_copy_file_range, fdIn, poffIn, fdOut, poffOut, cbChunk, fFlags);
+}
+
+
+DECL_NO_INLINE(static, bool) HasCopyFileRangeSyscallSlow(void)
+{
+    errno = 0;
+    MyCopyFileRangeSysCall(-1, NULL, -1, NULL, 4096, 0);
+    if (errno != ENOSYS)
+    {
+        ASMAtomicWriteS32(&g_fCopyFileRangeSupported, 1);
+        return true;
+    }
+    ASMAtomicWriteS32(&g_fCopyFileRangeSupported, 0);
+    return false;
+}
+
+DECLINLINE(bool) HasCopyFileRangeSyscall(void)
+{
+    int32_t i = ASMAtomicUoReadS32(&g_fCopyFileRangeSupported);
+    if (i != -1)
+        return i == 1;
+    return HasCopyFileRangeSyscallSlow();
+}
+
+
+
+RTDECL(int) RTFileCopyPartPrep(PRTFILECOPYPARTBUFSTATE pBufState, uint64_t cbToCopy)
+{
+    if (HasCopyFileRangeSyscall())
+    {
+        pBufState->iAllocType = -42;
+        pBufState->pbBuf      = NULL;
+        pBufState->cbBuf      = 0;
+        pBufState->uMagic     = RTFILECOPYPARTBUFSTATE_MAGIC;
+        return VINF_SUCCESS;
+    }
+    return rtFileCopyPartPrepFallback(pBufState, cbToCopy);
+}
+
+
+RTDECL(void) RTFileCopyPartCleanup(PRTFILECOPYPARTBUFSTATE pBufState)
+{
+    return rtFileCopyPartCleanupFallback(pBufState);
+}
+
+
+RTDECL(int) RTFileCopyPartEx(RTFILE hFileSrc, RTFOFF offSrc, RTFILE hFileDst, RTFOFF offDst, uint64_t cbToCopy,
+                             uint32_t fFlags, PRTFILECOPYPARTBUFSTATE pBufState, uint64_t *pcbCopied)
+{
+    /*
+     * Validate input.
+     */
+    if (pcbCopied)
+        *pcbCopied = 0;
+    AssertReturn(pBufState->uMagic == RTFILECOPYPARTBUFSTATE_MAGIC, VERR_INVALID_FLAGS);
+    if (pBufState->iAllocType == -42)
+    { /* more and more likely as time goes */ }
+    else
+        return rtFileCopyPartExFallback(hFileSrc, offSrc, hFileDst, offDst, cbToCopy, fFlags, pBufState, pcbCopied);
+    AssertReturn(offSrc >= 0, VERR_NEGATIVE_SEEK);
+    AssertReturn(offDst >= 0, VERR_NEGATIVE_SEEK);
+    AssertReturn(!fFlags, VERR_INVALID_FLAGS);
+
+    /*
+     * If nothing to copy, return right away.
+     */
+    if (!cbToCopy)
+        return VINF_SUCCESS;
+
+    /*
+     * Do the copying.
+     */
+    uint64_t cbCopied = 0;
+    int      rc       = VINF_SUCCESS;
+    do
+    {
+        size_t  cbThisCopy = (size_t)RT_MIN(cbToCopy - cbCopied, _1G);
+        loff_t  offThisDst = offSrc + cbCopied;
+        loff_t  offThisSrc = offDst + cbCopied;
+        ssize_t cbActual   = MyCopyFileRangeSysCall((int)RTFileToNative(hFileSrc), &offThisSrc,
+                                                    (int)RTFileToNative(hFileDst), &offThisDst,
+                                                    cbThisCopy, 0);
+        if (cbActual < 0)
+        {
+            rc = errno;
+            Assert(rc != 0);
+            rc = rc != 0 ? RTErrConvertFromErrno(rc) : VERR_READ_ERROR;
+            if (rc != VERR_NOT_SAME_DEVICE || cbCopied != 0)
+                break;
+
+            /* Fall back to generic implementation if the syscall refuses to handle the case. */
+            rc = rtFileCopyPartPrepFallback(pBufState, cbToCopy);
+            if (RT_SUCCESS(rc))
+                return rtFileCopyPartExFallback(hFileSrc, offSrc, hFileDst, offDst, cbToCopy, fFlags, pBufState, pcbCopied);
+            return rc;
+        }
+        Assert(offThisSrc == offSrc + (int64_t)cbCopied + cbActual);
+        Assert(offThisDst == offDst + (int64_t)cbCopied + cbActual);
+
+        if (cbActual == 0)
+        {
+            if (!pcbCopied)
+                rc = VERR_EOF;
+            break;
+        }
+
+        cbCopied += cbActual;
+    } while (cbCopied < cbToCopy);
+
+    if (pcbCopied)
+        *pcbCopied = cbCopied;
+
+    return rc;
+}
+
+#endif /* __NR_copy_file_range */
+
diff --git a/src/VBox/Runtime/r3/linux/RTFileQuerySectorSize-linux.cpp b/src/VBox/Runtime/r3/linux/RTFileQuerySectorSize-linux.cpp
new file mode 100644
index 00000000..ffd615fb
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTFileQuerySectorSize-linux.cpp
@@ -0,0 +1,88 @@
+/* $Id: RTFileQuerySectorSize-linux.cpp $ */
+/** @file
+ * IPRT - RTFileQuerySectorSize, Linux implementation.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <errno.h>
+#include <linux/fs.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+
+
+RTDECL(int) RTFileQuerySectorSize(RTFILE hFile, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pcbSector, VERR_INVALID_PARAMETER);
+
+    int rc;
+    int const fd = (int)RTFileToNative(hFile);
+    struct stat DevStat = { 0 };
+    if (!fstat(fd, &DevStat))
+    {
+        if (S_ISBLK(DevStat.st_mode))
+        {
+            int cbLogicalBlock = 0;
+            if (!ioctl(fd, BLKSSZGET, &cbLogicalBlock))
+            {
+                AssertReturn(cbLogicalBlock > 0, VERR_INVALID_FUNCTION);
+                *pcbSector = cbLogicalBlock;
+                return VINF_SUCCESS;
+            }
+
+            rc = RTErrConvertFromErrno(errno);
+            AssertMsgFailed(("ioctl failed: errno=%d / %Rrc\n", errno, rc));
+        }
+        else
+        {
+            AssertMsgFailed(("not a block device.\n"));
+            rc = VERR_INVALID_FUNCTION;
+        }
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(errno);
+        AssertMsgFailed(("fstat failed: errno=%d / %Rrc\n", errno, rc));
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/RTFileSetAllocationSize-linux.cpp b/src/VBox/Runtime/r3/linux/RTFileSetAllocationSize-linux.cpp
new file mode 100644
index 00000000..f3acd7fe
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTFileSetAllocationSize-linux.cpp
@@ -0,0 +1,86 @@
+/* $Id: RTFileSetAllocationSize-linux.cpp $ */
+/** @file
+ * IPRT - RTFileSetAllocationSize, linux implementation.
+ */
+
+/*
+ * Copyright (C) 2016-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/file.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/fcntl.h>
+
+/**
+ * The Linux specific fallocate() method.
+ */
+typedef int (*PFNLNXFALLOCATE) (int iFd, int fMode, off_t offStart, off_t cb);
+/** Flag to specify that the file size should not be extended. */
+#define LNX_FALLOC_FL_KEEP_SIZE 1
+
+RTDECL(int) RTFileSetAllocationSize(RTFILE hFile, uint64_t cbSize, uint32_t fFlags)
+{
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTFILE_ALLOC_SIZE_F_VALID), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(sizeof(off_t) >= sizeof(cbSize) ||  RT_HIDWORD(cbSize) == 0,
+                    ("64-bit filesize not supported! cbSize=%lld\n", cbSize),
+                    VERR_NOT_SUPPORTED);
+
+    int rc;
+    PFNLNXFALLOCATE pfnLnxFAllocate = (PFNLNXFALLOCATE)(uintptr_t)dlsym(RTLD_DEFAULT, "fallocate64");
+    if (RT_VALID_PTR(pfnLnxFAllocate))
+    {
+        int fLnxFlags = (fFlags & RTFILE_ALLOC_SIZE_F_KEEP_SIZE) ? LNX_FALLOC_FL_KEEP_SIZE : 0;
+        int rcLnx = pfnLnxFAllocate(RTFileToNative(hFile), fLnxFlags, 0, cbSize);
+        if (rcLnx == 0)
+            rc = VINF_SUCCESS;
+        else if (errno == EOPNOTSUPP)
+            rc = VERR_NOT_SUPPORTED;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTFileSetAllocationSize);
diff --git a/src/VBox/Runtime/r3/linux/RTProcIsRunningByName-linux.cpp b/src/VBox/Runtime/r3/linux/RTProcIsRunningByName-linux.cpp
new file mode 100644
index 00000000..6049fa1a
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTProcIsRunningByName-linux.cpp
@@ -0,0 +1,128 @@
+/* $Id: RTProcIsRunningByName-linux.cpp $ */
+/** @file
+ * IPRT - RTProcIsRunningByName, Linux implementation.
+ */
+
+/*
+ * Copyright (C) 2009-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/process.h>
+#include <iprt/string.h>
+#include <iprt/dir.h>
+#include <iprt/path.h>
+#include <iprt/stream.h>
+#include <iprt/param.h>
+#include <iprt/assert.h>
+
+#include <unistd.h>
+
+
+RTR3DECL(bool) RTProcIsRunningByName(const char *pszName)
+{
+    /*
+     * Quick validation.
+     */
+    if (!pszName)
+        return false;
+
+    bool const fWithPath = RTPathHavePath(pszName);
+
+    /*
+     * Enumerate /proc.
+     */
+    RTDIR hDir;
+    int rc = RTDirOpen(&hDir, "/proc");
+    AssertMsgRCReturn(rc, ("RTDirOpen on /proc failed: rc=%Rrc\n", rc), false);
+    if (RT_SUCCESS(rc))
+    {
+        RTDIRENTRY DirEntry;
+        while (RT_SUCCESS(RTDirRead(hDir, &DirEntry, NULL)))
+        {
+            /*
+             * Filter numeric directory entries only.
+             */
+            if (   (   DirEntry.enmType == RTDIRENTRYTYPE_DIRECTORY
+                    || DirEntry.enmType == RTDIRENTRYTYPE_UNKNOWN)
+                && RTStrToUInt32(DirEntry.szName) > 0)
+            {
+                /*
+                 * Try readlink on exe first since it's more faster and reliable.
+                 * Fall back on reading the first line in cmdline if that fails
+                 * (access errors typically). cmdline is unreliable as it might
+                 * contain whatever the execv caller passes as argv[0].
+                 */
+                char szName[RTPATH_MAX];
+                RTStrPrintf(szName, sizeof(szName), "/proc/%s/exe", &DirEntry.szName[0]);
+                char szExe[RTPATH_MAX];
+                int cchLink = readlink(szName, szExe, sizeof(szExe) - 1);
+                if (    cchLink > 0
+                    &&  (size_t)cchLink < sizeof(szExe))
+                {
+                    szExe[cchLink] = '\0';
+                    rc = VINF_SUCCESS;
+                }
+                else
+                {
+                    RTStrPrintf(szName, sizeof(szName), "/proc/%s/cmdline", &DirEntry.szName[0]);
+                    PRTSTREAM pStream;
+                    rc = RTStrmOpen(szName, "r", &pStream);
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = RTStrmGetLine(pStream, szExe, sizeof(szExe));
+                        RTStrmClose(pStream);
+                    }
+                }
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * We are interested on the file name part only.
+                     */
+                    char const *pszProcName = fWithPath ? szExe : RTPathFilename(szExe);
+                    if (RTStrCmp(pszProcName, pszName) == 0)
+                    {
+                        /* Found it! */
+                        RTDirClose(hDir);
+                        return true;
+                    }
+                }
+            }
+        }
+        RTDirClose(hDir);
+    }
+
+    return false;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/RTSystemFirmware-linux.cpp b/src/VBox/Runtime/r3/linux/RTSystemFirmware-linux.cpp
new file mode 100644
index 00000000..2d7b8986
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTSystemFirmware-linux.cpp
@@ -0,0 +1,115 @@
+/* $Id: RTSystemFirmware-linux.cpp $ */
+/** @file
+ * IPRT - System firmware information, linux.
+ */
+
+/*
+ * Copyright (C) 2019-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/system.h>
+
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/string.h>
+#include <iprt/linux/sysfs.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Defines the UEFI Globals UUID that is used here as filename suffix (case sensitive). */
+#define VBOX_UEFI_UUID_GLOBALS "8be4df61-93ca-11d2-aa0d-00e098032b8c"
+
+
+RTDECL(int) RTSystemQueryFirmwareType(PRTSYSFWTYPE penmFirmwareType)
+{
+    if (RTLinuxSysFsExists("firmware/efi/"))
+        *penmFirmwareType = RTSYSFWTYPE_UEFI;
+    else if (RTLinuxSysFsExists(""))
+        *penmFirmwareType = RTSYSFWTYPE_BIOS;
+    else
+    {
+        *penmFirmwareType = RTSYSFWTYPE_INVALID;
+        return VERR_NOT_SUPPORTED;
+    }
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTSystemQueryFirmwareType);
+
+
+RTDECL(int) RTSystemQueryFirmwareBoolean(RTSYSFWBOOL enmBoolean, bool *pfValue)
+{
+    *pfValue = false;
+
+    /*
+     * Translate the property to variable base filename.
+     */
+    const char *pszName;
+    switch (enmBoolean)
+    {
+        case RTSYSFWBOOL_SECURE_BOOT:
+            pszName = "firmware/efi/efivars/SecureBoot";
+            break;
+
+        default:
+            AssertReturn(enmBoolean > RTSYSFWBOOL_INVALID && enmBoolean < RTSYSFWBOOL_END, VERR_INVALID_PARAMETER);
+            return VERR_SYS_UNSUPPORTED_FIRMWARE_PROPERTY;
+
+    }
+
+    /*
+     * Try open and read the variable value.
+     */
+    RTFILE hFile;
+    int rc = RTLinuxSysFsOpen(&hFile, "%s-" VBOX_UEFI_UUID_GLOBALS, pszName);
+    /** @todo try other suffixes if file-not-found. */
+    if (RT_SUCCESS(rc))
+    {
+        uint8_t abBuf[16];
+        size_t  cbRead = 0;
+        rc = RTLinuxSysFsReadFile(hFile, abBuf, sizeof(abBuf), &cbRead);
+        *pfValue = cbRead > 1 && abBuf[cbRead - 1] != 0;
+        RTFileClose(hFile);
+    }
+    else if (rc == VERR_FILE_NOT_FOUND || rc == VERR_PATH_NOT_FOUND)
+        rc = VINF_SUCCESS;
+    else if (rc == VERR_PERMISSION_DENIED)
+        rc = VERR_NOT_SUPPORTED;
+
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSystemQueryFirmwareBoolean);
+
diff --git a/src/VBox/Runtime/r3/linux/RTSystemQueryDmiString-linux.cpp b/src/VBox/Runtime/r3/linux/RTSystemQueryDmiString-linux.cpp
new file mode 100644
index 00000000..91cf6eb2
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTSystemQueryDmiString-linux.cpp
@@ -0,0 +1,96 @@
+/* $Id: RTSystemQueryDmiString-linux.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryDmiString, linux ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/err.h>
+#include <iprt/assert.h>
+#include <iprt/linux/sysfs.h>
+
+#include <errno.h>
+
+
+RTDECL(int) RTSystemQueryDmiString(RTSYSDMISTR enmString, char *pszBuf, size_t cbBuf)
+{
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbBuf > 0, VERR_INVALID_PARAMETER);
+    *pszBuf = '\0';
+    AssertReturn(enmString > RTSYSDMISTR_INVALID && enmString < RTSYSDMISTR_END, VERR_INVALID_PARAMETER);
+
+    const char *pszSysFsName;
+    switch (enmString)
+    {
+        case RTSYSDMISTR_PRODUCT_NAME:      pszSysFsName = "id/product_name"; break;
+        case RTSYSDMISTR_PRODUCT_VERSION:   pszSysFsName = "id/product_version"; break;
+        case RTSYSDMISTR_PRODUCT_UUID:      pszSysFsName = "id/product_uuid"; break;
+        case RTSYSDMISTR_PRODUCT_SERIAL:    pszSysFsName = "id/product_serial"; break;
+        case RTSYSDMISTR_MANUFACTURER:      pszSysFsName = "id/sys_vendor"; break;
+        default:
+            return VERR_NOT_SUPPORTED;
+    }
+
+    size_t cbRead = 0;
+    int rc = RTLinuxSysFsReadStrFile(pszBuf, cbBuf, &cbRead, "devices/virtual/dmi/%s", pszSysFsName);
+    if (RT_FAILURE(rc) && rc != VERR_BUFFER_OVERFLOW)
+        rc = RTLinuxSysFsReadStrFile(pszBuf, cbBuf, &cbRead, "class/dmi/%s", pszSysFsName);
+    if (RT_FAILURE(rc) && rc != VERR_BUFFER_OVERFLOW)
+    {
+        switch (rc)
+        {
+            case VINF_SUCCESS:
+                AssertFailed();
+                break;
+            case VERR_FILE_NOT_FOUND:
+            case VERR_PATH_NOT_FOUND:
+            case VERR_IS_A_DIRECTORY:
+                rc = VERR_NOT_SUPPORTED;
+                break;
+            case VERR_PERMISSION_DENIED:
+            case VERR_ACCESS_DENIED:
+                rc = VERR_ACCESS_DENIED;
+                break;
+        }
+    }
+
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSystemQueryDmiString);
+
diff --git a/src/VBox/Runtime/r3/linux/RTSystemShutdown-linux.cpp b/src/VBox/Runtime/r3/linux/RTSystemShutdown-linux.cpp
new file mode 100644
index 00000000..fd198e30
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTSystemShutdown-linux.cpp
@@ -0,0 +1,111 @@
+/* $Id: RTSystemShutdown-linux.cpp $ */
+/** @file
+ * IPRT - RTSystemShutdown, linux implementation.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/process.h>
+#include <iprt/string.h>
+
+
+RTDECL(int) RTSystemShutdown(RTMSINTERVAL cMsDelay, uint32_t fFlags, const char *pszLogMsg)
+{
+    AssertPtrReturn(pszLogMsg, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTSYSTEM_SHUTDOWN_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Assemble the argument vector.
+     */
+    int         iArg = 0;
+    const char *apszArgs[6];
+
+    RT_BZERO(apszArgs, sizeof(apszArgs));
+
+    apszArgs[iArg++] = "/sbin/shutdown";
+    switch (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK)
+    {
+        case RTSYSTEM_SHUTDOWN_HALT:
+            apszArgs[iArg++] = "-h";
+            apszArgs[iArg++] = "-H";
+            break;
+        case RTSYSTEM_SHUTDOWN_REBOOT:
+            apszArgs[iArg++] = "-r";
+            break;
+        case RTSYSTEM_SHUTDOWN_POWER_OFF:
+        case RTSYSTEM_SHUTDOWN_POWER_OFF_HALT:
+            apszArgs[iArg++] = "-h";
+            apszArgs[iArg++] = "-P";
+            break;
+    }
+
+    char szWhen[80];
+    if (cMsDelay < 500)
+        strcpy(szWhen, "now");
+    else
+        RTStrPrintf(szWhen, sizeof(szWhen), "%u", (unsigned)((cMsDelay + 499) / 1000));
+    apszArgs[iArg++] = szWhen;
+
+    apszArgs[iArg++] = pszLogMsg;
+
+
+    /*
+     * Start the shutdown process and wait for it to complete.
+     */
+    RTPROCESS hProc;
+    int rc = RTProcCreate(apszArgs[0], apszArgs, RTENV_DEFAULT, 0 /*fFlags*/, &hProc);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    RTPROCSTATUS ProcStatus;
+    rc = RTProcWait(hProc, RTPROCWAIT_FLAGS_BLOCK, &ProcStatus);
+    if (RT_SUCCESS(rc))
+    {
+        if (   ProcStatus.enmReason != RTPROCEXITREASON_NORMAL
+            || ProcStatus.iStatus   != 0)
+            rc = VERR_SYS_SHUTDOWN_FAILED;
+    }
+
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSystemShutdown);
+
diff --git a/src/VBox/Runtime/r3/linux/RTThreadGetNativeState-linux.cpp b/src/VBox/Runtime/r3/linux/RTThreadGetNativeState-linux.cpp
new file mode 100644
index 00000000..26c0afdb
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/RTThreadGetNativeState-linux.cpp
@@ -0,0 +1,121 @@
+/* $Id: RTThreadGetNativeState-linux.cpp $ */
+/** @file
+ * IPRT - RTThreadGetNativeState, linux implementation.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/thread.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+#include "internal/thread.h"
+
+#include <unistd.h>
+#include <sys/fcntl.h>
+
+
+RTDECL(RTTHREADNATIVESTATE) RTThreadGetNativeState(RTTHREAD hThread)
+{
+    RTTHREADNATIVESTATE enmRet  = RTTHREADNATIVESTATE_INVALID;
+    PRTTHREADINT        pThread = rtThreadGet(hThread);
+    if (pThread)
+    {
+        enmRet = RTTHREADNATIVESTATE_UNKNOWN;
+
+        char szName[512];
+        RTStrPrintf(szName, sizeof(szName), "/proc/self/task/%u/stat", pThread->tid);
+        int fd = open(szName, O_RDONLY, 0);
+        if (fd >= 0)
+        {
+            ssize_t cch = read(fd, szName, sizeof(szName) - 1);
+            close(fd);
+            if (cch > 0)
+            {
+                szName[cch] = '\0';
+
+                /* skip the pid, the (comm name) and stop at the status char. */
+                const char *psz = szName;
+                while (   *psz
+                       && (   *psz != ')'
+                           || !RT_C_IS_SPACE(psz[1])
+                           || !RT_C_IS_ALPHA(psz[2])
+                           || !RT_C_IS_SPACE(psz[3])
+                          )
+                      )
+                    psz++;
+                if (*psz == ')')
+                {
+                    switch (psz[2])
+                    {
+                        case 'R':   /* running */
+                            enmRet = RTTHREADNATIVESTATE_RUNNING;
+                            break;
+
+                        case 'S':   /* sleeping */
+                        case 'D':   /* disk sleeping */
+                            enmRet = RTTHREADNATIVESTATE_BLOCKED;
+                            break;
+
+                        case 'T':   /* stopped or tracking stop */
+                            enmRet = RTTHREADNATIVESTATE_SUSPENDED;
+                            break;
+
+                        case 'Z':   /* zombie */
+                        case 'X':   /* dead */
+                            enmRet = RTTHREADNATIVESTATE_TERMINATED;
+                            break;
+
+                        default:
+                            AssertMsgFailed(("state=%c\n", psz[2]));
+                            enmRet = RTTHREADNATIVESTATE_UNKNOWN;
+                            break;
+                    }
+                }
+                else
+                    AssertMsgFailed(("stat='%s'\n", szName));
+            }
+        }
+        rtThreadRelease(pThread);
+    }
+    return enmRet;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/fileaio-linux.cpp b/src/VBox/Runtime/r3/linux/fileaio-linux.cpp
new file mode 100644
index 00000000..2f365a45
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/fileaio-linux.cpp
@@ -0,0 +1,847 @@
+/* $Id: fileaio-linux.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for the Linux host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/** @page pg_rtfileaio_linux     RTFile Async I/O - Linux Implementation Notes
+ * @internal
+ *
+ * Linux implements the kernel async I/O API through the io_* syscalls. They are
+ * not exposed in the glibc (the aio_* API uses userspace threads and blocking
+ * I/O operations to simulate async behavior). There is an external library
+ * called libaio which implements these syscalls but because we don't want to
+ * have another dependency and this library is not installed by default and the
+ * interface is really simple we use the kernel interface directly using wrapper
+ * functions.
+ *
+ * The interface has some limitations. The first one is that the file must be
+ * opened with O_DIRECT. This disables caching done by the kernel which can be
+ * compensated if the user of this API implements caching itself. The next
+ * limitation is that data buffers must be aligned at a 512 byte boundary or the
+ * request will fail.
+ */
+/** @todo r=bird: What's this about "must be opened with O_DIRECT"? An
+ *        explanation would be nice, esp. seeing what Linus is quoted saying
+ *        about it in the open man page... */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/asm.h>
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/thread.h>
+#include "internal/fileaio.h"
+
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <errno.h>
+
+#include <iprt/file.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** The async I/O context handle */
+typedef unsigned long LNXKAIOCONTEXT;
+
+/**
+ * Supported commands for the iocbs
+ */
+enum
+{
+    LNXKAIO_IOCB_CMD_READ   = 0,
+    LNXKAIO_IOCB_CMD_WRITE  = 1,
+    LNXKAIO_IOCB_CMD_FSYNC  = 2,
+    LNXKAIO_IOCB_CMD_FDSYNC = 3
+};
+
+/**
+ * The iocb structure of a request which is passed to the kernel.
+ *
+ * We redefined this here because the version in the header lacks padding
+ * for 32bit.
+ */
+typedef struct LNXKAIOIOCB
+{
+    /** Opaque pointer to data which is returned on an I/O event. */
+    void     *pvUser;
+#ifdef RT_ARCH_X86
+    uint32_t  u32Padding0;
+#endif
+    /** Contains the request number and is set by the kernel. */
+    uint32_t  u32Key;
+    /** Reserved. */
+    uint32_t  u32Reserved0;
+    /** The I/O opcode. */
+    uint16_t  u16IoOpCode;
+    /** Request priority. */
+    int16_t   i16Priority;
+    /** The file descriptor. */
+    uint32_t  uFileDesc;
+    /** The userspace pointer to the buffer containing/receiving the data. */
+    void     *pvBuf;
+#ifdef RT_ARCH_X86
+    uint32_t  u32Padding1;
+#endif
+    /** How many bytes to transfer. */
+#if ARCH_BITS == 32
+    uint32_t  cbTransfer;
+    uint32_t  u32Padding2;
+#elif ARCH_BITS == 64
+    uint64_t  cbTransfer;
+#else
+# error "Unknown architecture"
+#endif
+    /** At which offset to start the transfer. */
+    int64_t   off;
+    /** Reserved. */
+    uint64_t  u64Reserved1;
+    /** Flags */
+    uint32_t  fFlags;
+    /** Readyness signal file descriptor. */
+    uint32_t  u32ResFd;
+} LNXKAIOIOCB, *PLNXKAIOIOCB;
+
+/**
+ * I/O event structure to notify about completed requests.
+ * Redefined here too because of the padding.
+ */
+typedef struct LNXKAIOIOEVENT
+{
+    /** The pvUser field from the iocb. */
+    void         *pvUser;
+#if ARCH_BITS == 32
+    uint32_t      u32Padding0;
+#endif
+    /** The LNXKAIOIOCB object this event is for. */
+    PLNXKAIOIOCB *pIoCB;
+#if ARCH_BITS == 32
+    uint32_t      u32Padding1;
+#endif
+    /** The result code of the operation .*/
+#if ARCH_BITS == 32
+    int32_t       rc;
+    uint32_t      u32Padding2;
+#elif ARCH_BITS == 64
+    int64_t       rc;
+#else
+# error "Unknown architecture"
+#endif
+    /** Secondary result code. */
+#if ARCH_BITS == 32
+    int32_t       rc2;
+    uint32_t      u32Padding3;
+#elif ARCH_BITS == 64
+    int64_t       rc2;
+#else
+# error "Unknown architecture"
+#endif
+} LNXKAIOIOEVENT, *PLNXKAIOIOEVENT;
+
+
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** Handle to the async I/O context. */
+    LNXKAIOCONTEXT      AioContext;
+    /** Maximum number of requests this context can handle. */
+    int                 cRequestsMax;
+    /** Current number of requests active on this context. */
+    volatile int32_t    cRequests;
+    /** The ID of the thread which is currently waiting for requests. */
+    volatile RTTHREAD   hThreadWait;
+    /** Flag whether the thread was woken up. */
+    volatile bool       fWokenUp;
+    /** Flag whether the thread is currently waiting in the syscall. */
+    volatile bool       fWaiting;
+    /** Flags given during creation. */
+    uint32_t            fFlags;
+    /** Magic value (RTFILEAIOCTX_MAGIC). */
+    uint32_t            u32Magic;
+} RTFILEAIOCTXINTERNAL;
+/** Pointer to an internal context structure. */
+typedef RTFILEAIOCTXINTERNAL *PRTFILEAIOCTXINTERNAL;
+
+/**
+ * Async I/O request state.
+ */
+typedef struct RTFILEAIOREQINTERNAL
+{
+    /** The aio control block. This must be the FIRST elment in
+     *  the structure! (see notes below) */
+    LNXKAIOIOCB           AioCB;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE     enmState;
+    /** The I/O context this request is associated with. */
+    LNXKAIOCONTEXT        AioContext;
+    /** Return code the request completed with. */
+    int                   Rc;
+    /** Number of bytes actually transferred. */
+    size_t                cbTransfered;
+    /** Completion context we are assigned to. */
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    /** Magic value  (RTFILEAIOREQ_MAGIC). */
+    uint32_t              u32Magic;
+} RTFILEAIOREQINTERNAL;
+/** Pointer to an internal request structure. */
+typedef RTFILEAIOREQINTERNAL *PRTFILEAIOREQINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The max number of events to get in one call. */
+#define AIO_MAXIMUM_REQUESTS_PER_CONTEXT 64
+
+
+/**
+ * Creates a new async I/O context.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxCreate(unsigned cEvents, LNXKAIOCONTEXT *pAioContext)
+{
+    int rc = syscall(__NR_io_setup, cEvents, pAioContext);
+    if (RT_UNLIKELY(rc == -1))
+    {
+        if (errno == EAGAIN)
+            return VERR_FILE_AIO_INSUFFICIENT_EVENTS;
+        else
+            return RTErrConvertFromErrno(errno);
+    }
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Destroys a async I/O context.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxDestroy(LNXKAIOCONTEXT AioContext)
+{
+    int rc = syscall(__NR_io_destroy, AioContext);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Submits an array of I/O requests to the kernel.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxSubmit(LNXKAIOCONTEXT AioContext, long cReqs, LNXKAIOIOCB **ppIoCB, int *pcSubmitted)
+{
+    int rc = syscall(__NR_io_submit, AioContext, cReqs, ppIoCB);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    *pcSubmitted = rc;
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Cancels a I/O request.
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxCancel(LNXKAIOCONTEXT AioContext, PLNXKAIOIOCB pIoCB, PLNXKAIOIOEVENT pIoResult)
+{
+    int rc = syscall(__NR_io_cancel, AioContext, pIoCB, pIoResult);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Waits for I/O events.
+ * @returns Number of events (natural number w/ 0), IPRT error code (negative).
+ */
+DECLINLINE(int) rtFileAsyncIoLinuxGetEvents(LNXKAIOCONTEXT AioContext, long cReqsMin, long cReqs,
+                                            PLNXKAIOIOEVENT paIoResults, struct timespec *pTimeout)
+{
+    int rc = syscall(__NR_io_getevents, AioContext, cReqsMin, cReqs, paIoResults, pTimeout);
+    if (RT_UNLIKELY(rc == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    int rc = VINF_SUCCESS;
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+    /*
+     * Check if the API is implemented by creating a
+     * completion port.
+     */
+    LNXKAIOCONTEXT AioContext = 0;
+    rc = rtFileAsyncIoLinuxCreate(1, &AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rc = rtFileAsyncIoLinuxDestroy(AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Supported - fill in the limits. The alignment is the only restriction. */
+    pAioLimits->cReqsOutstandingMax = RTFILEAIO_UNLIMITED_REQS;
+    pAioLimits->cbBufferAlignment   = 512;
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    /*
+     * Allocate a new request and initialize it.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(*pReqInt));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    pReqInt->pCtxInt   = NULL;
+    pReqInt->u32Magic  = RTFILEAIOREQ_MAGIC;
+    RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+    *phReq = (RTFILEAIOREQ)pReqInt;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
+{
+    /*
+     * Validate the handle and ignore nil.
+     */
+    if (hReq == NIL_RTFILEAIOREQ)
+        return VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    /*
+     * Trash the magic and free it.
+     */
+    ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
+    RTMemFree(pReqInt);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Worker setting up the request.
+ */
+DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
+                                            uint16_t uTransferDirection,
+                                            RTFOFF off, void *pvBuf, size_t cbTransfer,
+                                            void *pvUser)
+{
+    /*
+     * Validate the input.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+
+    if (uTransferDirection != LNXKAIO_IOCB_CMD_FSYNC)
+    {
+        AssertPtr(pvBuf);
+        Assert(off >= 0);
+        Assert(cbTransfer > 0);
+    }
+
+    /*
+     * Setup the control block and clear the finished flag.
+     */
+    pReqInt->AioCB.u16IoOpCode = uTransferDirection;
+    pReqInt->AioCB.uFileDesc   = RTFileToNative(hFile);
+    pReqInt->AioCB.off         = off;
+    pReqInt->AioCB.cbTransfer  = cbTransfer;
+    pReqInt->AioCB.pvBuf       = pvBuf;
+    pReqInt->AioCB.pvUser      = pvUser;
+
+    pReqInt->pCtxInt           = NULL;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                    void *pvBuf, size_t cbRead, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LNXKAIO_IOCB_CMD_READ,
+                                       off, pvBuf, cbRead, pvUser);
+}
+
+
+RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                     void const *pvBuf, size_t cbWrite, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LNXKAIO_IOCB_CMD_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_HANDLE);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    return rtFileAioReqPrepareTransfer(pReqInt, hFile, LNXKAIO_IOCB_CMD_FSYNC,
+                                       0, NULL, 0, pvUser);
+}
+
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->AioCB.pvUser;
+}
+
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    LNXKAIOIOEVENT AioEvent;
+    int rc = rtFileAsyncIoLinuxCancel(pReqInt->AioContext, &pReqInt->AioCB, &AioEvent);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Decrement request count because the request will never arrive at the
+         * completion port.
+         */
+        AssertMsg(RT_VALID_PTR(pReqInt->pCtxInt), ("Invalid state. Request was canceled but wasn't submitted\n"));
+
+        ASMAtomicDecS32(&pReqInt->pCtxInt->cRequests);
+        pReqInt->Rc = VERR_FILE_AIO_CANCELED;
+        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+        return VINF_SUCCESS;
+    }
+    if (rc == VERR_TRY_AGAIN)
+        return VERR_FILE_AIO_IN_PROGRESS;
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    AssertPtrNull(pcbTransfered);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    if (    pcbTransfered
+        &&  RT_SUCCESS(pReqInt->Rc))
+        *pcbTransfered = pReqInt->cbTransfered;
+
+    return pReqInt->Rc;
+}
+
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
+                               uint32_t fFlags)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /* The kernel interface needs a maximum. */
+    if (cAioReqsMax == RTFILEAIO_UNLIMITED_REQS)
+        return VERR_OUT_OF_RANGE;
+
+    pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
+    if (RT_UNLIKELY(!pCtxInt))
+        return VERR_NO_MEMORY;
+
+    /* Init the event handle. */
+    int rc = rtFileAsyncIoLinuxCreate(cAioReqsMax, &pCtxInt->AioContext);
+    if (RT_SUCCESS(rc))
+    {
+        pCtxInt->fWokenUp     = false;
+        pCtxInt->fWaiting     = false;
+        pCtxInt->hThreadWait  = NIL_RTTHREAD;
+        pCtxInt->cRequestsMax = cAioReqsMax;
+        pCtxInt->fFlags       = fFlags;
+        pCtxInt->u32Magic     = RTFILEAIOCTX_MAGIC;
+        *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+    }
+    else
+        RTMemFree(pCtxInt);
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
+{
+    /* Validate the handle and ignore nil. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /* Cannot destroy a busy context. */
+    if (RT_UNLIKELY(pCtxInt->cRequests))
+        return VERR_FILE_AIO_BUSY;
+
+    /* The native bit first, then mark it as dead and free it. */
+    int rc = rtFileAsyncIoLinuxDestroy(pCtxInt->AioContext);
+    if (RT_FAILURE(rc))
+        return rc;
+    ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    /* Nil means global here. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return RTFILEAIO_UNLIMITED_REQS; /** @todo r=bird: I'm a bit puzzled by this return value since it
+                                          *                is completely useless in RTFileAioCtxCreate. */
+
+    /* Return 0 if the handle is invalid, it's better than garbage I think... */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN_RC(pCtxInt, 0);
+
+    return pCtxInt->cRequestsMax;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    /* Nothing to do. */
+    NOREF(hAioCtx); NOREF(hFile);
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    int rc = VINF_SUCCESS;
+
+    /*
+     * Parameter validation.
+     */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertReturn(cReqs > 0,  VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    uint32_t i = cReqs;
+    PRTFILEAIOREQINTERNAL pReqInt = NULL;
+
+    /*
+     * Validate requests and associate with the context.
+     */
+    while (i-- > 0)
+    {
+        pReqInt = pahReqs[i];
+        if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
+        {
+            /* Undo everything and stop submitting. */
+            size_t iUndo = cReqs;
+            while (iUndo-- > i)
+            {
+                pReqInt = pahReqs[iUndo];
+                RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                pReqInt->pCtxInt = NULL;
+            }
+            return VERR_INVALID_HANDLE;
+        }
+
+        pReqInt->AioContext = pCtxInt->AioContext;
+        pReqInt->pCtxInt    = pCtxInt;
+        RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+    }
+
+    do
+    {
+        /*
+         * We cast pahReqs to the Linux iocb structure to avoid copying the requests
+         * into a temporary array. This is possible because the iocb structure is
+         * the first element in the request structure (see PRTFILEAIOCTXINTERNAL).
+         */
+        int cReqsSubmitted = 0;
+        rc = rtFileAsyncIoLinuxSubmit(pCtxInt->AioContext, cReqs,
+                                      (PLNXKAIOIOCB *)pahReqs,
+                                      &cReqsSubmitted);
+        if (RT_FAILURE(rc))
+        {
+            /*
+             * We encountered an error.
+             * This means that the first IoCB
+             * is not correctly initialized
+             * (invalid buffer alignment or bad file descriptor).
+             * Revert every request into the prepared state except
+             * the first one which will switch to completed.
+             * Another reason could be insufficient resources.
+             */
+            i = cReqs;
+            while (i-- > 0)
+            {
+                /* Already validated. */
+                pReqInt = pahReqs[i];
+                pReqInt->pCtxInt    = NULL;
+                pReqInt->AioContext = 0;
+                RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+            }
+
+            if (rc == VERR_TRY_AGAIN)
+                return VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+            else
+            {
+                /* The first request failed. */
+                pReqInt = pahReqs[0];
+                RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                pReqInt->Rc = rc;
+                pReqInt->cbTransfered = 0;
+                return rc;
+            }
+        }
+
+        /* Advance. */
+        cReqs   -= cReqsSubmitted;
+        pahReqs += cReqsSubmitted;
+        ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmitted);
+
+    } while (cReqs);
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    /*
+     * Validate the parameters, making sure to always set pcReqs.
+     */
+    AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
+    *pcReqs = 0; /* always set */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
+    AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
+
+    /*
+     * Can't wait if there are not requests around.
+     */
+    if (   RT_UNLIKELY(ASMAtomicUoReadS32(&pCtxInt->cRequests) == 0)
+        && !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
+        return VERR_FILE_AIO_NO_REQUEST;
+
+    /*
+     * Convert the timeout if specified.
+     */
+    struct timespec    *pTimeout = NULL;
+    struct timespec     Timeout = {0,0};
+    uint64_t            StartNanoTS = 0;
+    if (cMillies != RT_INDEFINITE_WAIT)
+    {
+        Timeout.tv_sec  = cMillies / 1000;
+        Timeout.tv_nsec = cMillies % 1000 * 1000000;
+        pTimeout = &Timeout;
+        StartNanoTS = RTTimeNanoTS();
+    }
+
+    /* Wait for at least one. */
+    if (!cMinReqs)
+        cMinReqs = 1;
+
+    /* For the wakeup call. */
+    Assert(pCtxInt->hThreadWait == NIL_RTTHREAD);
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, RTThreadSelf());
+
+    /*
+     * Loop until we're woken up, hit an error (incl timeout), or
+     * have collected the desired number of requests.
+     */
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+    while (!pCtxInt->fWokenUp)
+    {
+        LNXKAIOIOEVENT  aPortEvents[AIO_MAXIMUM_REQUESTS_PER_CONTEXT];
+        int             cRequestsToWait = RT_MIN(cReqs, AIO_MAXIMUM_REQUESTS_PER_CONTEXT);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
+        rc = rtFileAsyncIoLinuxGetEvents(pCtxInt->AioContext, cMinReqs, cRequestsToWait, &aPortEvents[0], pTimeout);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
+        if (RT_FAILURE(rc))
+            break;
+        uint32_t const cDone = rc;
+        rc = VINF_SUCCESS;
+
+        /*
+         * Process received events / requests.
+         */
+        for (uint32_t i = 0; i < cDone; i++)
+        {
+            /*
+             * The iocb is the first element in our request structure.
+             * So we can safely cast it directly to the handle (see above)
+             */
+            PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)aPortEvents[i].pIoCB;
+            AssertPtr(pReqInt);
+            Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
+
+            /** @todo aeichner: The rc field contains the result code
+             *  like you can find in errno for the normal read/write ops.
+             *  But there is a second field called rc2. I don't know the
+             *  purpose for it yet.
+             */
+            if (RT_UNLIKELY(aPortEvents[i].rc < 0))
+                pReqInt->Rc = RTErrConvertFromErrno(-aPortEvents[i].rc); /* Convert to positive value. */
+            else
+            {
+                pReqInt->Rc = VINF_SUCCESS;
+                pReqInt->cbTransfered = aPortEvents[i].rc;
+            }
+
+            /* Mark the request as finished. */
+            RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+            pahReqs[cRequestsCompleted++] = (RTFILEAIOREQ)pReqInt;
+        }
+
+        /*
+         * Done Yet? If not advance and try again.
+         */
+        if (cDone >= cMinReqs)
+            break;
+        cMinReqs -= cDone;
+        cReqs    -= cDone;
+
+        if (cMillies != RT_INDEFINITE_WAIT)
+        {
+            /* The API doesn't return ETIMEDOUT, so we have to fix that ourselves. */
+            uint64_t NanoTS = RTTimeNanoTS();
+            uint64_t cMilliesElapsed = (NanoTS - StartNanoTS) / 1000000;
+            if (cMilliesElapsed >= cMillies)
+            {
+                rc = VERR_TIMEOUT;
+                break;
+            }
+
+            /* The syscall supposedly updates it, but we're paranoid. :-) */
+            Timeout.tv_sec  = (cMillies - (RTMSINTERVAL)cMilliesElapsed) / 1000;
+            Timeout.tv_nsec = (cMillies - (RTMSINTERVAL)cMilliesElapsed) % 1000 * 1000000;
+        }
+    }
+
+    /*
+     * Update the context state and set the return value.
+     */
+    *pcReqs = cRequestsCompleted;
+    ASMAtomicSubS32(&pCtxInt->cRequests, cRequestsCompleted);
+    Assert(pCtxInt->hThreadWait == RTThreadSelf());
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, NIL_RTTHREAD);
+
+    /*
+     * Clear the wakeup flag and set rc.
+     */
+    if (    pCtxInt->fWokenUp
+        &&  RT_SUCCESS(rc))
+    {
+        ASMAtomicXchgBool(&pCtxInt->fWokenUp, false);
+        rc = VERR_INTERRUPTED;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /** @todo r=bird: Define the protocol for how to resume work after calling
+     *        this function. */
+
+    bool fWokenUp    = ASMAtomicXchgBool(&pCtxInt->fWokenUp, true);
+
+    /*
+     * Read the thread handle before the status flag.
+     * If we read the handle after the flag we might
+     * end up with an invalid handle because the thread
+     * waiting in RTFileAioCtxWakeup() might get scheduled
+     * before we read the flag and returns.
+     * We can ensure that the handle is valid if fWaiting is true
+     * when reading the handle before the status flag.
+     */
+    RTTHREAD hThread;
+    ASMAtomicReadHandle(&pCtxInt->hThreadWait, &hThread);
+    bool fWaiting    = ASMAtomicReadBool(&pCtxInt->fWaiting);
+    if (    !fWokenUp
+        &&  fWaiting)
+    {
+        /*
+         * If a thread waits the handle must be valid.
+         * It is possible that the thread returns from
+         * rtFileAsyncIoLinuxGetEvents() before the signal
+         * is send.
+         * This is no problem because we already set fWokenUp
+         * to true which will let the thread return VERR_INTERRUPTED
+         * and the next call to RTFileAioCtxWait() will not
+         * return VERR_INTERRUPTED because signals are not saved
+         * and will simply vanish if the destination thread can't
+         * receive it.
+         */
+        Assert(hThread != NIL_RTTHREAD);
+        RTThreadPoke(hThread);
+    }
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/ioqueue-iouringfile-provider.cpp b/src/VBox/Runtime/r3/linux/ioqueue-iouringfile-provider.cpp
new file mode 100644
index 00000000..f6719664
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/ioqueue-iouringfile-provider.cpp
@@ -0,0 +1,940 @@
+/* $Id: ioqueue-iouringfile-provider.cpp $ */
+/** @file
+ * IPRT - I/O queue, Linux io_uring interface I/O file provider.
+ */
+
+/*
+ * Copyright (C) 2019-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/** @page pg_rtioqueue_linux     RTIoQueue - Linux io_uring implementation notes
+ * @internal
+ *
+ * The io_uring interface is the most recent interface added to the Linux kernel
+ * to deliver fast and efficient I/O. It was first added with kernel version 5.1 and is
+ * thus not available on most systems as of writing this backend (July 2019).
+ * It supersedes the old async I/O interface and cleans up with some restrictions like
+ * having to disable caching for the file.
+ * The interface is centered around a submission and completion queue to queue multiple new
+ * requests for the kernel to process and get notified about completions to reduce the amount
+ * of context switches to an absolute minimum. It also offers advanced features like
+ * registering a fixed set of memory buffers for I/O upfront to reduce the processing overhead
+ * even more.
+ *
+ * The first implementation will only make use of the basic features and more advanced features
+ * will be added later.
+ * The adept developer probably noticed that the public IPRT I/O queue API resembles the io_uring
+ * interface in many aspects. This is not by accident but to reduce our own overhead as much as possible
+ * while still keeping a consistent platform independent API which allows efficient implementations on
+ * other hosts when they come up.
+ *
+ * The public kernel io_uring interface is completely defined in this file to avoid dragging in additional
+ * dependencies and to avoid compile problems on older hosts missing the interface just like it is done
+ * for the Linux RTFileAio* API  The necessary interface definitions and descriptions where retrieved from:
+ *     * http://kernel.dk/io_uring.pdf
+ *     * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/io_uring.h
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_IOQUEUE
+#include <iprt/ioqueue.h>
+
+#include <iprt/assertcompile.h>
+#include <iprt/asm.h>
+#include <iprt/errcore.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <sys/uio.h>
+
+#include "internal/ioqueue.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+
+/** The syscall number of io_uring_setup(). */
+#define LNX_IOURING_SYSCALL_SETUP     425
+/** The syscall number of io_uring_enter(). */
+#define LNX_IOURING_SYSCALL_ENTER     426
+/** The syscall number of io_uring_register(). */
+#define LNX_IOURING_SYSCALL_REGISTER  427
+/** eventfd2() syscall not associated with io_uring but used for kicking waiters. */
+#define LNX_SYSCALL_EVENTFD2          290
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Linux io_uring completion event.
+ */
+typedef struct LNXIOURINGCQE
+{
+    /** Opaque user data associated with the completed request. */
+    uint64_t                    u64User;
+    /** The status code of the request. */
+    int32_t                     rcLnx;
+    /** Some flags which are not used as of now. */
+    uint32_t                    fFlags;
+} LNXIOURINGCQE;
+AssertCompileSize(LNXIOURINGCQE, 16);
+/** Pointer to a Linux io_uring completion event. */
+typedef LNXIOURINGCQE *PLNXIOURINGCQE;
+/** Pointer to a constant linux io_uring completion event. */
+typedef const LNXIOURINGCQE *PCLNXIOURINGCQE;
+
+
+/**
+ * Linux io_uring submission queue entry.
+ */
+typedef struct LNXIOURINGSQE
+{
+    /** The opcode for the request. */
+    uint8_t                     u8Opc;
+    /** Common flags for the request. */
+    uint8_t                     u8Flags;
+    /** Assigned I/O priority. */
+    uint16_t                    u16IoPrio;
+    /** The file descriptor the request is for. */
+    int32_t                     i32Fd;
+    /** The start offset into the file for the request. */
+    uint64_t                    u64OffStart;
+    /** Buffer pointer or Pointer to io vector array depending on opcode. */
+    uint64_t                    u64AddrBufIoVec;
+    /** Size of the buffer in bytes or number of io vectors. */
+    uint32_t                    u32BufIoVecSz;
+    /** Opcode dependent data. */
+    union
+    {
+        /** Flags for read/write requests. */
+        uint32_t                u32KrnlRwFlags;
+        /** Flags for fsync() like requests. */
+        uint32_t                u32FsyncFlags;
+        /** Flags for poll() like requests. */
+        uint16_t                u16PollFlags;
+        /** Flags for sync_file_range() like requests. */
+        uint32_t                u32SyncFileRangeFlags;
+        /** Flags for requests requiring a msg structure. */
+        uint32_t                u32MsgFlags;
+    } uOpc;
+    /** Opaque user data associated with the request and returned durign completion. */
+    uint64_t                    u64User;
+    /** Request type dependent data. */
+    union
+    {
+        /** Fixed buffer index if indicated by the request flags. */
+        uint16_t                u16FixedBufIdx;
+        /** Padding to align the structure to 64 bytes. */
+        uint64_t                au64Padding[3];
+    } uReq;
+} LNXIOURINGSQE;
+AssertCompileSize(LNXIOURINGSQE, 64);
+/** Pointer to a Linux io_uring submission queue entry. */
+typedef LNXIOURINGSQE *PLNXIOURINGSQE;
+/** Pointer to a constant Linux io_uring submission queue entry. */
+typedef const LNXIOURINGSQE *PCLNXIOURINGSQE;
+
+
+/**
+ * Linux u_ioring SQ ring header structure to maintain the queue.
+ */
+typedef struct LNXIOURINGSQ
+{
+    /** The current head position to fill in new requests. */
+    uint32_t                    u32OffHead;
+    /** The current tail position the kernel starts processing from. */
+    uint32_t                    u32OffTail;
+    /** The mask for the head and tail counters to apply to retrieve the index. */
+    uint32_t                    u32OffRingMask;
+    /** Number of entries in the SQ ring. */
+    uint32_t                    u32OffRingEntries;
+    /** Flags set asychronously by the kernel. */
+    uint32_t                    u32OffFlags;
+    /** Counter of dropped requests. */
+    uint32_t                    u32OffDroppedReqs;
+    /** Offset where to find the array of SQ entries. */
+    uint32_t                    u32OffArray;
+    /** Reserved. */
+    uint32_t                    u32Rsvd0;
+    /** Reserved. */
+    uint64_t                    u64Rsvd1;
+} LNXIOURINGSQ;
+AssertCompileSize(LNXIOURINGSQ, 40);
+/** Pointer to a Linux u_ioring SQ ring header. */
+typedef LNXIOURINGSQ *PLNXIOURINGSQ;
+/** Pointer to a constant Linux u_ioring SQ ring header. */
+typedef const LNXIOURINGSQ *PCLNXIOURINGSQ;
+
+
+/**
+ * Linux io_uring CQ ring header structure to maintain the queue.
+ */
+typedef struct LNXIOURINGCQ
+{
+    /** The current head position the kernel modifies when completion events happen. */
+    uint32_t                    u32OffHead;
+    /** The current tail position to read completion events from. */
+    uint32_t                    u32OffTail;
+    /** The mask for the head and tail counters to apply to retrieve the index. */
+    uint32_t                    u32OffRingMask;
+    /** Number of entries in the CQ ring. */
+    uint32_t                    u32OffRingEntries;
+    /** Number of CQ overflows happened. */
+    uint32_t                    u32OffOverflowCnt;
+    /** */
+    uint32_t                    u32OffCqes;
+    /** Reserved. */
+    uint64_t                    au64Rsvd0[2];
+} LNXIOURINGCQ;
+AssertCompileSize(LNXIOURINGCQ, 40);
+/** Pointer to a Linux u_ioring CQ ring header. */
+typedef LNXIOURINGCQ *PLNXIOURINGCQ;
+/** Pointer to a constant Linux u_ioring CQ ring header. */
+typedef const LNXIOURINGCQ *PCLNXIOURINGCQ;
+
+
+/**
+ * Linux io_uring parameters passed to io_uring_setup().
+ */
+typedef struct LNXIOURINGPARAMS
+{
+    /** Number of SQ entries requested, must be power of 2. */
+    uint32_t                    u32SqEntriesCnt;
+    /** Number of CQ entries requested, must be power of 2. */
+    uint32_t                    u32CqEntriesCnt;
+    /** Flags for the ring, , see LNX_IOURING_SETUP_F_*. */
+    uint32_t                    u32Flags;
+    /** Affinity of the kernel side SQ polling thread if enabled. */
+    uint32_t                    u32SqPollCpu;
+    /** Milliseconds after the kernel side SQ polling thread goes to sleep
+     * if there is are no requests to process. */
+    uint32_t                    u32SqPollIdleMs;
+    /** Reserved. */
+    uint32_t                    au32Rsvd0[5];
+    /** Offsets returned for the submission queue. */
+    LNXIOURINGSQ                SqOffsets;
+    /** Offsets returned for the completion queue. */
+    LNXIOURINGCQ                CqOffsets;
+} LNXIOURINGPARAMS;
+/** Pointer to Linux io_uring parameters. */
+typedef LNXIOURINGPARAMS *PLNXIOURINGPARAMS;
+/** Pointer to constant Linux io_uring parameters. */
+typedef const LNXIOURINGPARAMS *PCLNXIOURINGPARAMS;
+
+
+/** @name LNXIOURINGSQE::u8Opc defined opcodes.
+ * @{ */
+/** Opcode to profile the interface, does nothing. */
+#define LNX_IOURING_OPC_NOP             0
+/** preadv() like request. */
+#define LNX_IOURING_OPC_READV           1
+/** pwritev() like request. */
+#define LNX_IOURING_OPC_WRITEV          2
+/** fsync() like request. */
+#define LNX_IOURING_OPC_FSYNC           3
+/** Read request using a fixed preset buffer. */
+#define LNX_IOURING_OPC_READ_FIXED      4
+/** Write request using a fixed preset buffer. */
+#define LNX_IOURING_OPC_WRITE_FIXED     5
+/** Add file descriptor to pollset. */
+#define LNX_IOURING_OPC_POLL_ADD        6
+/** Remove file descriptor from pollset. */
+#define LNX_IOURING_OPC_POLL_REMOVE     7
+/** sync_file_range() like request. */
+#define LNX_IOURING_OPC_SYNC_FILE_RANGE 8
+/** sendmsg() like request. */
+#define LNX_IOURING_OPC_SENDMSG         9
+/** recvmsg() like request. */
+#define LNX_IOURING_OPC_RECVMSG         10
+/** @} */
+
+
+/** @name Additional flags for LNX_IOURING_OPC_FSYNC requests.
+ * @{ */
+/** Sync userdata as well instead of metadata only. */
+#define LNX_IOURING_OPC_FSYNC_DATASYNC  RT_BIT_32(0)
+/** @} */
+
+
+/** @name Flags for the LNX_IOURING_SYSCALL_SETUP syscall.
+ * @{ */
+/** The I/O context is polled. */
+#define LNX_IOURING_SETUP_F_IOPOLL      RT_BIT_32(0)
+/** The kernel should poll the submission queue. */
+#define LNX_IOURING_SETUP_F_SQPOLL      RT_BIT_32(1)
+/** Sets the CPU affinity of the kernel thread polling the submission queue. */
+#define LNX_IOURING_SETUP_F_SQAFF       RT_BIT_32(2)
+/** @} */
+
+
+/** @name Flags for LNXIOURINGSQE::u8Flags.
+ * @{ */
+/** The file descriptor was registered before use. */
+#define LNX_IOURING_SQE_F_FIXED_FILE    RT_BIT(0)
+/** Complete all active requests before issuing the request with the flag set. */
+#define LNX_IOURING_SQE_F_IO_DRAIN      RT_BIT(1)
+/** Links the request with the flag set to the next one. */
+#define LNX_IOURING_SQE_F_IO_LINK       RT_BIT(2)
+/** @} */
+
+
+/** @name Magic mmap offsets to map submission and completion queues.
+ * @{ */
+/** Used to map the submission queue. */
+#define LNX_IOURING_MMAP_OFF_SQ         UINT64_C(0)
+/** Used to map the completion queue. */
+#define LNX_IOURING_MMAP_OFF_CQ         UINT64_C(0x8000000)
+/** Used to map the submission queue entries array. */
+#define LNX_IOURING_MMAP_OFF_SQES       UINT64_C(0x10000000)
+/** @} */
+
+
+/** @name Flags used for the SQ ring structure.
+ * @{ */
+/** The kernel thread needs a io_uring_enter() wakeup to continue processing requests. */
+#define LNX_IOURING_SQ_RING_F_NEED_WAKEUP           RT_BIT_32(0)
+/** @} */
+
+
+/** @name Flags for the LNX_IOURING_SYSCALL_ENTER syscall.
+ * @{ */
+/** Retrieve completion events for the completion queue. */
+#define LNX_IOURING_ENTER_F_GETEVENTS               RT_BIT_32(0)
+/** Wakes the suspended kernel thread processing the requests. */
+#define LNX_IOURING_ENTER_F_SQ_WAKEUP               RT_BIT_32(1)
+/** @} */
+
+
+/** @name Opcodes for the LNX_IOURING_SYSCALL_REGISTER syscall.
+ * @{ */
+/** Register a fixed set of buffers. */
+#define LNX_IOURING_REGISTER_OPC_BUFFERS_REGISTER   0
+/** Unregisters a fixed set of buffers registered previously. */
+#define LNX_IOURING_REGISTER_OPC_BUFFERS_UNREGISTER 1
+/** Register a fixed set of files. */
+#define LNX_IOURING_REGISTER_OPC_FILES_REGISTER     2
+/** Unregisters a fixed set of files registered previously. */
+#define LNX_IOURING_REGISTER_OPC_FILES_UNREGISTER   3
+/** Register an eventfd associated with the I/O ring. */
+#define LNX_IOURING_REGISTER_OPC_EVENTFD_REGISTER   4
+/** Unregisters an eventfd registered previously. */
+#define LNX_IOURING_REGISTER_OPC_EVENTFD_UNREGISTER 5
+/** @} */
+
+
+/**
+ * SQ ring structure.
+ *
+ * @note Some members of this structure point to memory shared with the kernel,
+ *       hence the volatile keyword.
+ */
+typedef struct RTIOQUEUESQ
+{
+    /** Pointer to the head counter. */
+    volatile uint32_t           *pidxHead;
+    /** Pointer to the tail counter. */
+    volatile uint32_t           *pidxTail;
+    /** Mask to apply for the counters to get to the index. */
+    uint32_t                    fRingMask;
+    /** Number of entries in the ring. */
+    uint32_t                    cEntries;
+    /** Pointer to the global flags. */
+    volatile uint32_t           *pfFlags;
+    /** Pointer to the indirection array used for indexing the real SQ entries. */
+    volatile uint32_t           *paidxSqes;
+} RTIOQUEUESQ;
+
+
+/**
+ * CQ ring structure.
+ *
+ * @note Some members of this structure point to memory shared with the kernel,
+ *       hence the volatile keyword.
+ */
+typedef struct RTIOQUEUECQ
+{
+    /** Pointer to the head counter. */
+    volatile uint32_t           *pidxHead;
+    /** Pointer to the tail counter. */
+    volatile uint32_t           *pidxTail;
+    /** Mask to apply for the counters to get to the index. */
+    uint32_t                    fRingMask;
+    /** Number of entries in the ring. */
+    uint32_t                    cEntries;
+    /** Pointer to the completion entry ring. */
+    volatile LNXIOURINGCQE      *paCqes;
+} RTIOQUEUECQ;
+
+
+/**
+ * Internal I/O queue provider instance data.
+ */
+typedef struct RTIOQUEUEPROVINT
+{
+    /** The io_uring file descriptor. */
+    int                         iFdIoCtx;
+    /** The eventfd file descriptor registered with the ring. */
+    int                         iFdEvt;
+    /** The submission queue. */
+    RTIOQUEUESQ                 Sq;
+    /** The currently uncommitted tail for the SQ. */
+    uint32_t                    idxSqTail;
+    /** Numbere of uncommitted SQEs. */
+    uint32_t                    cSqesToCommit;
+    /** The completion queue. */
+    RTIOQUEUECQ                 Cq;
+    /** Pointer to the mapped SQES entries. */
+    PLNXIOURINGSQE              paSqes;
+    /** Pointer to the iovec structure used for non S/G requests. */
+    struct iovec                *paIoVecs;
+    /** Pointer returned by mmap() for the SQ ring, used for unmapping. */
+    void                        *pvMMapSqRing;
+    /** Pointer returned by mmap() for the CQ ring, used for unmapping. */
+    void                        *pvMMapCqRing;
+    /** Pointer returned by mmap() for the SQ entries array, used for unmapping. */
+    void                        *pvMMapSqes;
+    /** Size of the mapped SQ ring, used for unmapping. */
+    size_t                      cbMMapSqRing;
+    /** Size of the mapped CQ ring, used for unmapping. */
+    size_t                      cbMMapCqRing;
+    /** Size of the mapped SQ entries array, used for unmapping. */
+    size_t                      cbMMapSqes;
+    /** Flag whether the waiter was woken up externally. */
+    volatile bool               fExtIntr;
+} RTIOQUEUEPROVINT;
+/** Pointer to the internal I/O queue provider instance data. */
+typedef RTIOQUEUEPROVINT *PRTIOQUEUEPROVINT;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Syscall wrapper for io_uring_setup().
+ *
+ * @returns IPRT status code.
+ * @param   cEntries            Number of entries for submission and completion queues.
+ * @param   pParams             Additional parameters for the I/O ring and updated return values
+ *                              on success.
+ * @param   piFdIoCtx           Where to store the file descriptor of the I/O ring on success.
+ */
+DECLINLINE(int) rtIoQueueLnxIoURingSetup(uint32_t cEntries, PLNXIOURINGPARAMS pParams, int32_t *piFdIoCtx)
+{
+    int rcLnx = syscall(LNX_IOURING_SYSCALL_SETUP, cEntries, pParams);
+    if (RT_UNLIKELY(rcLnx == -1))
+        return RTErrConvertFromErrno(errno);
+
+    *piFdIoCtx = rcLnx;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Syscall wrapper for io_uring_enter().
+ *
+ * @returns IPRT status code.
+ * @param   iFdIoCtx            The I/O ring file descriptor.
+ * @param   cToSubmit           Maximum number of requests waiting for processing.
+ * @param   cMinComplete        Minimum number of completion events to accumulate before returning.
+ * @param   fFlags              Flags for io_uring_enter(), see LNX_IOURING_ENTER_F_*.
+ */
+DECLINLINE(int) rtIoQueueLnxIoURingEnter(int32_t iFdIoCtx, uint32_t cToSubmit, uint32_t cMinComplete,
+                                         uint32_t fFlags)
+{
+    int rcLnx = syscall(LNX_IOURING_SYSCALL_ENTER, iFdIoCtx, cToSubmit, cMinComplete, fFlags,
+                        NULL, 0);
+    if (RT_UNLIKELY(rcLnx == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Syscall wrapper for io_uring_register().
+ *
+ * @returns IPRT status code.
+ * @param   iFdIoCtx            The I/O ring file descriptor.
+ * @param   uOpc                Operation to perform, see LNX_IOURING_REGISTER_OPC_*.
+ * @param   pvArg               Opaque arguments.
+ * @param   cArgs               Number of arguments.
+ */
+DECLINLINE(int) rtIoQueueLnxIoURingRegister(int32_t iFdIoCtx, uint32_t uOpc, void *pvArg,
+                                            uint32_t cArgs)
+{
+    int rcLnx = syscall(LNX_IOURING_SYSCALL_REGISTER, iFdIoCtx, uOpc, pvArg, cArgs);
+    if (RT_UNLIKELY(rcLnx == -1))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * mmap() wrapper for the common bits and returning an IPRT status code.
+ *
+ * @returns IPRT status code.
+ * @param   iFdIoCtx            The I/O ring file descriptor.
+ * @param   offMmap             The mmap() offset.
+ * @param   cbMmap              How much to map.
+ * @param   ppv                 Where to store the pointer to the mapping on success.
+ */
+DECLINLINE(int) rtIoQueueLnxIoURingMmap(int iFdIoCtx, off_t offMmap, size_t cbMmap, void **ppv)
+{
+    void *pv = mmap(0, cbMmap, PROT_READ | PROT_WRITE , MAP_SHARED | MAP_POPULATE, iFdIoCtx, offMmap);
+    if (pv != MAP_FAILED)
+    {
+        *ppv = pv;
+        return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromErrno(errno);
+}
+
+
+/**
+ * eventfd2() syscall wrapper.
+ *
+ * @returns IPRT status code.
+ * @param   uValInit            The initial value of the maintained counter.
+ * @param   fFlags              Flags controlling the eventfd behavior.
+ * @param   piFdEvt             Where to store the file descriptor of the eventfd object on success.
+ */
+DECLINLINE(int) rtIoQueueLnxEventfd2(uint32_t uValInit, uint32_t fFlags, int *piFdEvt)
+{
+    int rcLnx = syscall(LNX_SYSCALL_EVENTFD2, uValInit, fFlags);
+    if (RT_UNLIKELY(rcLnx == -1))
+        return RTErrConvertFromErrno(errno);
+
+    *piFdEvt = rcLnx;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks the completion event queue for pending events.
+ *
+ * @param   pThis               The provider instance.
+ * @param   paCEvt              Pointer to the array of completion events.
+ * @param   cCEvt               Maximum number of completion events the array can hold.
+ * @param   pcCEvtSeen          Where to store the number of completion events processed.
+ */
+static void rtIoQueueLnxIoURingFileProvCqCheck(PRTIOQUEUEPROVINT pThis, PRTIOQUEUECEVT paCEvt,
+                                               uint32_t cCEvt, uint32_t *pcCEvtSeen)
+{
+    /* The fencing and atomic accesses are kind of overkill and probably not required (dev paranoia). */
+    ASMReadFence();
+    uint32_t idxCqHead = ASMAtomicReadU32(pThis->Cq.pidxHead);
+    uint32_t idxCqTail = ASMAtomicReadU32(pThis->Cq.pidxTail);
+    ASMReadFence();
+
+    uint32_t cCEvtSeen = 0;
+
+    while (   idxCqTail != idxCqHead
+           && cCEvtSeen < cCEvt)
+    {
+        /* Get the index. */
+        uint32_t idxCqe = idxCqHead & pThis->Cq.fRingMask;
+        volatile LNXIOURINGCQE *pCqe = &pThis->Cq.paCqes[idxCqe];
+
+        paCEvt->pvUser = (void *)(uintptr_t)pCqe->u64User;
+        if (pCqe->rcLnx >= 0)
+        {
+            paCEvt->rcReq    = VINF_SUCCESS;
+            paCEvt->cbXfered = (size_t)pCqe->rcLnx;
+        }
+        else
+            paCEvt->rcReq = RTErrConvertFromErrno(-pCqe->rcLnx);
+
+#ifdef RT_STRICT /* poison */
+        memset((void *)pCqe, 0xff, sizeof(*pCqe));
+#endif
+
+        paCEvt++;
+        cCEvtSeen++;
+        idxCqHead++;
+    }
+
+    *pcCEvtSeen = cCEvtSeen;
+
+    /* Paranoia strikes again. */
+    ASMWriteFence();
+    ASMAtomicWriteU32(pThis->Cq.pidxHead, idxCqHead);
+    ASMWriteFence();
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnIsSupported} */
+static DECLCALLBACK(bool) rtIoQueueLnxIoURingFileProv_IsSupported(void)
+{
+    /*
+     * Try to create a simple I/O ring and close it again.
+     * The common code/public API already checked for the proper handle type.
+     */
+    int iFdIoCtx = 0;
+    bool fSupp = false;
+    LNXIOURINGPARAMS Params;
+    RT_ZERO(Params);
+
+    int rc = rtIoQueueLnxIoURingSetup(16, &Params, &iFdIoCtx);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Check that we can register an eventfd descriptor to get notified about
+         * completion events while being able to kick the waiter externally out of the wait.
+         */
+        int iFdEvt = 0;
+        rc = rtIoQueueLnxEventfd2(0 /*uValInit*/, 0 /*fFlags*/, &iFdEvt);
+        if (RT_SUCCESS(rc))
+        {
+            rc = rtIoQueueLnxIoURingRegister(iFdIoCtx, LNX_IOURING_REGISTER_OPC_EVENTFD_REGISTER,
+                                             &iFdEvt, 1 /*cArgs*/);
+            if (RT_SUCCESS(rc))
+                fSupp = true;
+
+            int rcLnx = close(iFdEvt); Assert(!rcLnx); RT_NOREF(rcLnx);
+        }
+        int rcLnx = close(iFdIoCtx); Assert(!rcLnx); RT_NOREF(rcLnx);
+    }
+
+    return fSupp;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnQueueInit} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_QueueInit(RTIOQUEUEPROV hIoQueueProv, uint32_t fFlags,
+                                                               uint32_t cSqEntries, uint32_t cCqEntries)
+{
+    RT_NOREF(fFlags, cCqEntries);
+
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+    LNXIOURINGPARAMS Params;
+    RT_ZERO(Params);
+
+    pThis->cSqesToCommit = 0;
+    pThis->fExtIntr      = false;
+
+    int rc = rtIoQueueLnxIoURingSetup(cSqEntries, &Params, &pThis->iFdIoCtx);
+    if (RT_SUCCESS(rc))
+    {
+        /* Map the rings into userspace. */
+        pThis->cbMMapSqRing = Params.SqOffsets.u32OffArray + Params.u32SqEntriesCnt * sizeof(uint32_t);
+        pThis->cbMMapCqRing = Params.CqOffsets.u32OffCqes + Params.u32CqEntriesCnt * sizeof(LNXIOURINGCQE);
+        pThis->cbMMapSqes   = Params.u32SqEntriesCnt * sizeof(LNXIOURINGSQE);
+
+        pThis->paIoVecs = (struct iovec *)RTMemAllocZ(Params.u32SqEntriesCnt * sizeof(struct iovec));
+        if (RT_LIKELY(pThis->paIoVecs))
+        {
+            rc = rtIoQueueLnxEventfd2(0 /*uValInit*/, 0 /*fFlags*/, &pThis->iFdEvt);
+            if (RT_SUCCESS(rc))
+            {
+                rc = rtIoQueueLnxIoURingRegister(pThis->iFdIoCtx, LNX_IOURING_REGISTER_OPC_EVENTFD_REGISTER, &pThis->iFdEvt, 1 /*cArgs*/);
+                if (RT_SUCCESS(rc))
+                {
+                    rc = rtIoQueueLnxIoURingMmap(pThis->iFdIoCtx, LNX_IOURING_MMAP_OFF_SQ, pThis->cbMMapSqRing, &pThis->pvMMapSqRing);
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = rtIoQueueLnxIoURingMmap(pThis->iFdIoCtx, LNX_IOURING_MMAP_OFF_CQ, pThis->cbMMapCqRing, &pThis->pvMMapCqRing);
+                        if (RT_SUCCESS(rc))
+                        {
+                            rc = rtIoQueueLnxIoURingMmap(pThis->iFdIoCtx, LNX_IOURING_MMAP_OFF_SQES, pThis->cbMMapSqes, &pThis->pvMMapSqes);
+                            if (RT_SUCCESS(rc))
+                            {
+                                uint8_t *pbTmp = (uint8_t *)pThis->pvMMapSqRing;
+
+                                pThis->Sq.pidxHead  = (uint32_t *)(pbTmp + Params.SqOffsets.u32OffHead);
+                                pThis->Sq.pidxTail  = (uint32_t *)(pbTmp + Params.SqOffsets.u32OffTail);
+                                pThis->Sq.fRingMask = *(uint32_t *)(pbTmp + Params.SqOffsets.u32OffRingMask);
+                                pThis->Sq.cEntries  = *(uint32_t *)(pbTmp + Params.SqOffsets.u32OffRingEntries);
+                                pThis->Sq.pfFlags   = (uint32_t *)(pbTmp + Params.SqOffsets.u32OffFlags);
+                                pThis->Sq.paidxSqes = (uint32_t *)(pbTmp + Params.SqOffsets.u32OffArray);
+                                pThis->idxSqTail    = *pThis->Sq.pidxTail;
+
+                                pThis->paSqes       = (PLNXIOURINGSQE)pThis->pvMMapSqes;
+
+                                pbTmp = (uint8_t *)pThis->pvMMapCqRing;
+
+                                pThis->Cq.pidxHead  = (uint32_t *)(pbTmp + Params.CqOffsets.u32OffHead);
+                                pThis->Cq.pidxTail  = (uint32_t *)(pbTmp + Params.CqOffsets.u32OffTail);
+                                pThis->Cq.fRingMask = *(uint32_t *)(pbTmp + Params.CqOffsets.u32OffRingMask);
+                                pThis->Cq.cEntries  = *(uint32_t *)(pbTmp + Params.CqOffsets.u32OffRingEntries);
+                                pThis->Cq.paCqes    = (PLNXIOURINGCQE)(pbTmp + Params.CqOffsets.u32OffCqes);
+                                return VINF_SUCCESS;
+                            }
+
+                            munmap(pThis->pvMMapCqRing, pThis->cbMMapCqRing);
+                        }
+
+                        munmap(pThis->pvMMapSqRing, pThis->cbMMapSqRing);
+                    }
+
+                    rc = rtIoQueueLnxIoURingRegister(pThis->iFdIoCtx, LNX_IOURING_REGISTER_OPC_EVENTFD_UNREGISTER, NULL, 0);
+                    AssertRC(rc);
+                }
+
+                close(pThis->iFdEvt);
+            }
+
+            RTMemFree(pThis->paIoVecs);
+        }
+
+        int rcLnx = close(pThis->iFdIoCtx); Assert(!rcLnx); RT_NOREF(rcLnx);
+    }
+
+    return rc;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnQueueDestroy} */
+static DECLCALLBACK(void) rtIoQueueLnxIoURingFileProv_QueueDestroy(RTIOQUEUEPROV hIoQueueProv)
+{
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+
+    int rcLnx = munmap(pThis->pvMMapSqRing, pThis->cbMMapSqRing); Assert(!rcLnx); RT_NOREF(rcLnx);
+    rcLnx = munmap(pThis->pvMMapCqRing, pThis->cbMMapCqRing); Assert(!rcLnx); RT_NOREF(rcLnx);
+    rcLnx = munmap(pThis->pvMMapSqes, pThis->cbMMapSqes); Assert(!rcLnx); RT_NOREF(rcLnx);
+
+    int rc = rtIoQueueLnxIoURingRegister(pThis->iFdIoCtx, LNX_IOURING_REGISTER_OPC_EVENTFD_UNREGISTER, NULL, 0);
+    AssertRC(rc);
+
+    close(pThis->iFdEvt);
+    close(pThis->iFdIoCtx);
+    RTMemFree(pThis->paIoVecs);
+
+    RT_ZERO(pThis);
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnHandleRegister} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_HandleRegister(RTIOQUEUEPROV hIoQueueProv, PCRTHANDLE pHandle)
+{
+    RT_NOREF(hIoQueueProv, pHandle);
+    /** @todo Add support for fixed file sets later. */
+    return VINF_SUCCESS;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnHandleDeregister} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_HandleDeregister(RTIOQUEUEPROV hIoQueueProv, PCRTHANDLE pHandle)
+{
+    RT_NOREF(hIoQueueProv, pHandle);
+    /** @todo Add support for fixed file sets later. */
+    return VINF_SUCCESS;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnReqPrepare} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_ReqPrepare(RTIOQUEUEPROV hIoQueueProv, PCRTHANDLE pHandle, RTIOQUEUEOP enmOp,
+                                                                uint64_t off, void *pvBuf, size_t cbBuf, uint32_t fReqFlags,
+                                                                void *pvUser)
+{
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+    RT_NOREF(fReqFlags);
+
+    uint32_t idx = pThis->idxSqTail & pThis->Sq.fRingMask;
+    PLNXIOURINGSQE pSqe = &pThis->paSqes[idx];
+    struct iovec *pIoVec = &pThis->paIoVecs[idx];
+
+    pIoVec->iov_base = pvBuf;
+    pIoVec->iov_len  = cbBuf;
+
+    pSqe->u8Flags         = 0;
+    pSqe->u16IoPrio       = 0;
+    pSqe->i32Fd           = (int32_t)RTFileToNative(pHandle->u.hFile);
+    pSqe->u64OffStart     = off;
+    pSqe->u64AddrBufIoVec = (uint64_t)(uintptr_t)pIoVec;
+    pSqe->u32BufIoVecSz   = 1;
+    pSqe->u64User         = (uint64_t)(uintptr_t)pvUser;
+
+    switch (enmOp)
+    {
+        case RTIOQUEUEOP_READ:
+            pSqe->u8Opc               = LNX_IOURING_OPC_READV;
+            pSqe->uOpc.u32KrnlRwFlags = 0;
+            break;
+        case RTIOQUEUEOP_WRITE:
+            pSqe->u8Opc               = LNX_IOURING_OPC_WRITEV;
+            pSqe->uOpc.u32KrnlRwFlags = 0;
+            break;
+        case RTIOQUEUEOP_SYNC:
+            pSqe->u8Opc              = LNX_IOURING_OPC_FSYNC;
+            pSqe->uOpc.u32FsyncFlags = 0;
+            break;
+        default:
+            AssertMsgFailedReturn(("Invalid I/O queue operation: %d\n", enmOp),
+                                  VERR_INVALID_PARAMETER);
+    }
+
+    pThis->Sq.paidxSqes[idx] = idx;
+    pThis->idxSqTail++;
+    pThis->cSqesToCommit++;
+    return VINF_SUCCESS;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnCommit} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_Commit(RTIOQUEUEPROV hIoQueueProv, uint32_t *pcReqsCommitted)
+{
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+
+    ASMWriteFence();
+    ASMAtomicWriteU32(pThis->Sq.pidxTail, pThis->idxSqTail);
+    ASMWriteFence();
+
+    int rc = rtIoQueueLnxIoURingEnter(pThis->iFdIoCtx, pThis->cSqesToCommit, 0, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        *pcReqsCommitted = pThis->cSqesToCommit;
+        pThis->cSqesToCommit = 0;
+    }
+
+    return rc;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnEvtWait} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_EvtWait(RTIOQUEUEPROV hIoQueueProv, PRTIOQUEUECEVT paCEvt, uint32_t cCEvt,
+                                                             uint32_t cMinWait, uint32_t *pcCEvt, uint32_t fFlags)
+{
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+    int rc = VINF_SUCCESS;
+    uint32_t cCEvtSeen = 0;
+
+    RT_NOREF(fFlags);
+
+    /*
+     * Check the completion queue first for any completed events which might save us a
+     * context switch later on.
+     */
+    rtIoQueueLnxIoURingFileProvCqCheck(pThis, paCEvt, cCEvt, &cCEvtSeen);
+
+    while (   cCEvtSeen < cMinWait
+           && RT_SUCCESS(rc))
+    {
+        /*
+         * We can employ a blocking read on the event file descriptor, it will return
+         * either when woken up externally or when there are completion events pending.
+         */
+        uint64_t uCnt = 0; /**< The counter value returned upon a successful read(). */
+        ssize_t rcLnx = read(pThis->iFdEvt, &uCnt, sizeof(uCnt));
+        if (rcLnx == sizeof(uCnt))
+        {
+            uint32_t cCEvtThisSeen = 0;
+            rtIoQueueLnxIoURingFileProvCqCheck(pThis, &paCEvt[cCEvtSeen], cCEvt - cCEvtSeen, &cCEvtThisSeen);
+            cCEvtSeen += cCEvtThisSeen;
+
+            /* Whether we got woken up externally. */
+            if (ASMAtomicXchgBool(&pThis->fExtIntr, false))
+                rc = VERR_INTERRUPTED;
+        }
+        else if (rcLnx == -1)
+            rc = RTErrConvertFromErrno(errno);
+        else
+            AssertMsgFailed(("Unexpected read() -> 0\n"));
+    }
+
+    *pcCEvt = cCEvtSeen;
+    return rc;
+}
+
+
+/** @interface_method_impl{RTIOQUEUEPROVVTABLE,pfnEvtWaitWakeup} */
+static DECLCALLBACK(int) rtIoQueueLnxIoURingFileProv_EvtWaitWakeup(RTIOQUEUEPROV hIoQueueProv)
+{
+    PRTIOQUEUEPROVINT pThis = hIoQueueProv;
+    int rc = VINF_SUCCESS;
+
+    if (!ASMAtomicXchgBool(&pThis->fExtIntr, true))
+    {
+        const uint64_t uValAdd = 1;
+        ssize_t rcLnx = write(pThis->iFdEvt, &uValAdd, sizeof(uValAdd));
+
+        Assert(rcLnx == -1 || rcLnx == sizeof(uValAdd));
+        if (rcLnx == -1)
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+/**
+ * Async file I/O queue provider virtual method table.
+ */
+RT_DECL_DATA_CONST(RTIOQUEUEPROVVTABLE const) g_RTIoQueueLnxIoURingProv =
+{
+    /** uVersion */
+    RTIOQUEUEPROVVTABLE_VERSION,
+    /** pszId */
+    "LnxIoURingFile",
+    /** cbIoQueueProv */
+    sizeof(RTIOQUEUEPROVINT),
+    /** enmHnd */
+    RTHANDLETYPE_FILE,
+    /** fFlags */
+    0,
+    /** pfnIsSupported */
+    rtIoQueueLnxIoURingFileProv_IsSupported,
+    /** pfnQueueInit  */
+    rtIoQueueLnxIoURingFileProv_QueueInit,
+    /** pfnQueueDestroy */
+    rtIoQueueLnxIoURingFileProv_QueueDestroy,
+    /** pfnHandleRegister */
+    rtIoQueueLnxIoURingFileProv_HandleRegister,
+    /** pfnHandleDeregister */
+    rtIoQueueLnxIoURingFileProv_HandleDeregister,
+    /** pfnReqPrepare */
+    rtIoQueueLnxIoURingFileProv_ReqPrepare,
+    /** pfnReqPrepareSg */
+    NULL,
+    /** pfnCommit */
+    rtIoQueueLnxIoURingFileProv_Commit,
+    /** pfnEvtWait */
+    rtIoQueueLnxIoURingFileProv_EvtWait,
+    /** pfnEvtWaitWakeup */
+    rtIoQueueLnxIoURingFileProv_EvtWaitWakeup,
+    /** uEndMarker */
+    RTIOQUEUEPROVVTABLE_VERSION
+};
+
diff --git a/src/VBox/Runtime/r3/linux/krnlmod-linux.cpp b/src/VBox/Runtime/r3/linux/krnlmod-linux.cpp
new file mode 100644
index 00000000..6d81d530
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/krnlmod-linux.cpp
@@ -0,0 +1,358 @@
+/* $Id: krnlmod-linux.cpp $ */
+/** @file
+ * IPRT - Kernel module, Linux.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/krnlmod.h>
+#include <iprt/linux/sysfs.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/dir.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/types.h>
+
+
+/**
+ * Internal kernel information record state.
+ */
+typedef struct RTKRNLMODINFOINT
+{
+    /** Reference counter. */
+    volatile uint32_t   cRefs;
+    /** Reference count for the kernel module. */
+    uint32_t            cRefKrnlMod;
+    /** Load address of the kernel module. */
+    RTR0UINTPTR         uLoadAddr;
+    /** Size of the kernel module. */
+    size_t              cbKrnlMod;
+    /** Size of the name in characters including the zero terminator. */
+    size_t              cchName;
+    /** Module name - variable in size. */
+    char                achName[1];
+} RTKRNLMODINFOINT;
+/** Pointer to the internal kernel module information record. */
+typedef RTKRNLMODINFOINT *PRTKRNLMODINFOINT;
+/** Pointer to a const internal kernel module information record. */
+typedef const RTKRNLMODINFOINT *PCRTKRNLMODINFOINT;
+
+
+
+/**
+ * Destroy the given kernel module information record.
+ *
+ * @param   pThis            The record to destroy.
+ */
+static void rtKrnlModInfoDestroy(PRTKRNLMODINFOINT pThis)
+{
+    RTMemFree(pThis);
+}
+
+
+static int rtKrnlModLinuxReadIntFileDef(unsigned uBase, int64_t *pi64, int64_t i64Def,
+                                        const char *pszName, const char *pszPath)
+{
+    int rc = RTLinuxSysFsReadIntFile(uBase, pi64, "module/%s/%s", pszName, pszPath);
+    if (rc == VERR_FILE_NOT_FOUND)
+    {
+        *pi64 = i64Def;
+        rc = VINF_SUCCESS;
+    }
+
+    return rc;
+}
+
+/**
+ * Creates a new kernel module information record for the given module.
+ *
+ * @returns IPRT status code.
+ * @param   pszName          The kernel module name.
+ * @param   phKrnlModInfo    Where to store the handle to the kernel module information record
+ *                           on success.
+ */
+static int rtKrnlModLinuxInfoCreate(const char *pszName, PRTKRNLMODINFO phKrnlModInfo)
+{
+    int rc = VINF_SUCCESS;
+    size_t cchName = strlen(pszName) + 1;
+    PRTKRNLMODINFOINT pThis = (PRTKRNLMODINFOINT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTKRNLMODINFOINT, achName[cchName]));
+    if (RT_LIKELY(pThis))
+    {
+        memcpy(&pThis->achName[0], pszName, cchName);
+        pThis->cchName     = cchName;
+        pThis->cRefs       = 1;
+
+        int64_t iTmp = 0;
+        rc = rtKrnlModLinuxReadIntFileDef(10, &iTmp, 0, pszName, "refcnt");
+        if (RT_SUCCESS(rc))
+            pThis->cRefKrnlMod = (uint32_t)iTmp;
+
+        rc = rtKrnlModLinuxReadIntFileDef(10, &iTmp, 0, pszName, "coresize");
+        if (RT_SUCCESS(rc))
+            pThis->cbKrnlMod = iTmp;
+
+        rc = rtKrnlModLinuxReadIntFileDef(16, &iTmp, 0, pszName, "sections/.text");
+        if (RT_SUCCESS(rc))
+            pThis->uLoadAddr = iTmp;
+
+        if (RT_SUCCESS(rc))
+            *phKrnlModInfo = pThis;
+        else
+            RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModQueryLoaded(const char *pszName, bool *pfLoaded)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfLoaded, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsExists("module/%s", pszName);
+    if (rc == VINF_SUCCESS)
+        *pfLoaded = true;
+    else if (rc == VERR_FILE_NOT_FOUND)
+    {
+        *pfLoaded = false;
+        rc = VINF_SUCCESS;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfo(const char *pszName, PRTKRNLMODINFO phKrnlModInfo)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(phKrnlModInfo, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsExists("module/%s", pszName);
+    if (rc == VINF_SUCCESS)
+        rc = rtKrnlModLinuxInfoCreate(pszName, phKrnlModInfo);
+    else if (rc == VERR_FILE_NOT_FOUND)
+        rc = VERR_NOT_FOUND;
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModLoadedGetCount(void)
+{
+    uint32_t cKmodsLoaded = 0;
+
+    RTDIR hDir = NULL;
+    int rc = RTDirOpen(&hDir, "/sys/module");
+    if (RT_SUCCESS(rc))
+    {
+        RTDIRENTRY DirEnt;
+        rc = RTDirRead(hDir, &DirEnt, NULL);
+        while (RT_SUCCESS(rc))
+        {
+            if (!RTDirEntryIsStdDotLink(&DirEnt))
+                cKmodsLoaded++;
+            rc = RTDirRead(hDir, &DirEnt, NULL);
+        }
+
+        RTDirClose(hDir);
+    }
+
+
+    return cKmodsLoaded;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfoAll(PRTKRNLMODINFO pahKrnlModInfo, uint32_t cEntriesMax,
+                                        uint32_t *pcEntries)
+{
+    if (cEntriesMax > 0)
+        AssertPtrReturn(pahKrnlModInfo, VERR_INVALID_POINTER);
+
+    uint32_t cKmodsLoaded = RTKrnlModLoadedGetCount();
+    if (cEntriesMax < cKmodsLoaded)
+    {
+        if (*pcEntries)
+            *pcEntries = cKmodsLoaded;
+        return VERR_BUFFER_OVERFLOW;
+    }
+
+    RTDIR hDir = NULL;
+    int rc = RTDirOpen(&hDir, "/sys/module");
+    if (RT_SUCCESS(rc))
+    {
+        unsigned idxKrnlModInfo = 0;
+        RTDIRENTRY DirEnt;
+
+        rc = RTDirRead(hDir, &DirEnt, NULL);
+        while (RT_SUCCESS(rc))
+        {
+            if (!RTDirEntryIsStdDotLink(&DirEnt))
+            {
+                rc = rtKrnlModLinuxInfoCreate(DirEnt.szName, &pahKrnlModInfo[idxKrnlModInfo]);
+                if (RT_SUCCESS(rc))
+                    idxKrnlModInfo++;
+            }
+
+            if (RT_SUCCESS(rc))
+                rc = RTDirRead(hDir, &DirEnt, NULL);
+        }
+
+        if (rc == VERR_NO_MORE_FILES)
+            rc = VINF_SUCCESS;
+        else if (RT_FAILURE(rc))
+        {
+            /* Rollback */
+            while (idxKrnlModInfo-- > 0)
+                RTKrnlModInfoRelease(pahKrnlModInfo[idxKrnlModInfo]);
+        }
+
+        if (*pcEntries)
+            *pcEntries = cKmodsLoaded;
+
+        RTDirClose(hDir);
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRetain(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRelease(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    if (!pThis)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtKrnlModInfoDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoGetRefCnt(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cRefKrnlMod;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetName(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return &pThis->achName[0];
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetFilePath(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return NULL;
+}
+
+
+RTDECL(size_t) RTKrnlModInfoGetSize(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cbKrnlMod;
+}
+
+
+RTDECL(RTR0UINTPTR) RTKrnlModInfoGetLoadAddr(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->uLoadAddr;
+}
+
+
+RTDECL(int) RTKrnlModInfoQueryRefModInfo(RTKRNLMODINFO hKrnlModInfo, uint32_t idx,
+                                         PRTKRNLMODINFO phKrnlModInfoRef)
+{
+    RT_NOREF3(hKrnlModInfo, idx, phKrnlModInfoRef);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByPath(const char *pszPath)
+{
+    AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModUnloadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
diff --git a/src/VBox/Runtime/r3/linux/mp-linux.cpp b/src/VBox/Runtime/r3/linux/mp-linux.cpp
new file mode 100644
index 00000000..935dfd22
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/mp-linux.cpp
@@ -0,0 +1,328 @@
+/* $Id: mp-linux.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, Linux.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <stdio.h>
+#include <errno.h>
+
+#include <iprt/mp.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/cpuset.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/linux/sysfs.h>
+
+
+/**
+ * Internal worker that determines the max possible CPU count.
+ *
+ * @returns Max cpus.
+ */
+static RTCPUID rtMpLinuxMaxCpus(void)
+{
+#if 0 /* this doesn't do the right thing :-/ */
+    int cMax = sysconf(_SC_NPROCESSORS_CONF);
+    Assert(cMax >= 1);
+    return cMax;
+#else
+    static uint32_t s_cMax = 0;
+    if (!s_cMax)
+    {
+        int cMax = 1;
+        for (unsigned iCpu = 0; iCpu < RTCPUSET_MAX_CPUS; iCpu++)
+            if (RTLinuxSysFsExists("devices/system/cpu/cpu%d", iCpu))
+                cMax = iCpu + 1;
+        ASMAtomicUoWriteU32((uint32_t volatile *)&s_cMax, cMax);
+        return cMax;
+    }
+    return s_cMax;
+#endif
+}
+
+/**
+ * Internal worker that picks the processor speed in MHz from /proc/cpuinfo.
+ *
+ * @returns CPU frequency.
+ */
+static uint32_t rtMpLinuxGetFrequency(RTCPUID idCpu)
+{
+    FILE *pFile = fopen("/proc/cpuinfo", "r");
+    if (!pFile)
+        return 0;
+
+    char sz[256];
+    RTCPUID idCpuFound = NIL_RTCPUID;
+    uint32_t Frequency = 0;
+    while (fgets(sz, sizeof(sz), pFile))
+    {
+        char *psz;
+        if (   !strncmp(sz, RT_STR_TUPLE("processor"))
+            && (sz[10] == ' ' || sz[10] == '\t' || sz[10] == ':')
+            && (psz = strchr(sz, ':')))
+        {
+            psz += 2;
+            int64_t iCpu;
+            int rc = RTStrToInt64Ex(psz, NULL, 0, &iCpu);
+            if (RT_SUCCESS(rc))
+                idCpuFound = iCpu;
+        }
+        else if (   idCpu == idCpuFound
+                 && !strncmp(sz, RT_STR_TUPLE("cpu MHz"))
+                 && (sz[10] == ' ' || sz[10] == '\t' || sz[10] == ':')
+                 && (psz = strchr(sz, ':')))
+        {
+            psz += 2;
+            int64_t v;
+            int rc = RTStrToInt64Ex(psz, &psz, 0, &v);
+            if (RT_SUCCESS(rc))
+            {
+                Frequency = v;
+                break;
+            }
+        }
+    }
+    fclose(pFile);
+    return Frequency;
+}
+
+
+/** @todo RTmpCpuId(). */
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    return idCpu < rtMpLinuxMaxCpus() ? (int)idCpu : -1;
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    return (unsigned)iCpu < rtMpLinuxMaxCpus() ? iCpu : NIL_RTCPUID;
+}
+
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    return rtMpLinuxMaxCpus() - 1;
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+    /** @todo check if there is a simpler interface than this... */
+    int64_t i = 0;
+    int rc = RTLinuxSysFsReadIntFile(0, &i, "devices/system/cpu/cpu%d/online", (int)idCpu);
+    if (    RT_FAILURE(rc)
+        &&  RTLinuxSysFsExists("devices/system/cpu/cpu%d", (int)idCpu))
+    {
+        /** @todo Assert(!RTLinuxSysFsExists("devices/system/cpu/cpu%d/online",
+         *               (int)idCpu));
+         * Unfortunately, the online file wasn't always world readable (centos
+         * 2.6.18-164). */
+        i = 1;
+        rc = VINF_SUCCESS;
+    }
+
+    AssertMsg(i == 0 || i == -1 || i == 1, ("i=%d\n", i));
+    return RT_SUCCESS(rc) && i != 0;
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    /** @todo check this up with hotplugging! */
+    return RTLinuxSysFsExists("devices/system/cpu/cpu%d", (int)idCpu);
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    RTCPUID cMax = rtMpLinuxMaxCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuPossible(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    RTCPUSET Set;
+    RTMpGetSet(&Set);
+    return RTCpuSetCount(&Set);
+}
+
+
+RTDECL(RTCPUID) RTMpGetCoreCount(void)
+{
+    RTCPUID     cMax      = rtMpLinuxMaxCpus();
+    uint32_t   *paidCores = (uint32_t *)alloca(sizeof(paidCores[0]) * (cMax + 1));
+    uint32_t   *paidPckgs = (uint32_t *)alloca(sizeof(paidPckgs[0]) * (cMax + 1));
+    uint32_t    cCores    = 0;
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+    {
+        if (RTMpIsCpuPossible(idCpu))
+        {
+            int64_t idCore = 0;
+            int64_t idPckg = 0;
+
+            int rc = RTLinuxSysFsReadIntFile(0, &idCore, "devices/system/cpu/cpu%d/topology/core_id", (int)idCpu);
+            if (RT_SUCCESS(rc))
+                rc = RTLinuxSysFsReadIntFile(0, &idPckg, "devices/system/cpu/cpu%d/topology/physical_package_id", (int)idCpu);
+
+            if (RT_SUCCESS(rc))
+            {
+                uint32_t i;
+
+                for (i = 0; i < cCores; i++)
+                    if (   paidCores[i] == (uint32_t)idCore
+                        && paidPckgs[i] == (uint32_t)idPckg)
+                        break;
+                if (i >= cCores)
+                {
+                    paidCores[cCores] = (uint32_t)idCore;
+                    paidPckgs[cCores] = (uint32_t)idPckg;
+                    cCores++;
+                }
+            }
+        }
+    }
+    Assert(cCores > 0);
+    return cCores;
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    RTCPUID cMax = rtMpLinuxMaxCpus();
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+        if (RTMpIsCpuOnline(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+    RTCPUSET Set;
+    RTMpGetOnlineSet(&Set);
+    return RTCpuSetCount(&Set);
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCoreCount(void)
+{
+    RTCPUID     cMax      = rtMpLinuxMaxCpus();
+    uint32_t   *paidCores = (uint32_t *)alloca(sizeof(paidCores[0]) * (cMax + 1));
+    uint32_t   *paidPckgs = (uint32_t *)alloca(sizeof(paidPckgs[0]) * (cMax + 1));
+    uint32_t    cCores    = 0;
+    for (RTCPUID idCpu = 0; idCpu < cMax; idCpu++)
+    {
+        if (RTMpIsCpuOnline(idCpu))
+        {
+            int64_t idCore = 0;
+            int64_t idPckg = 0;
+
+            int rc = RTLinuxSysFsReadIntFile(0, &idCore, "devices/system/cpu/cpu%d/topology/core_id", (int)idCpu);
+            if (RT_SUCCESS(rc))
+                rc = RTLinuxSysFsReadIntFile(0, &idPckg, "devices/system/cpu/cpu%d/topology/physical_package_id", (int)idCpu);
+
+            if (RT_SUCCESS(rc))
+            {
+                uint32_t i;
+
+                for (i = 0; i < cCores; i++)
+                    if (   paidCores[i] == idCore
+                        && paidPckgs[i] == idPckg)
+                        break;
+                if (i >= cCores)
+                {
+                    paidCores[cCores] = idCore;
+                    paidPckgs[cCores] = idPckg;
+                    cCores++;
+                }
+            }
+        }
+    }
+    Assert(cCores > 0);
+    return cCores;
+}
+
+
+
+RTDECL(uint32_t) RTMpGetCurFrequency(RTCPUID idCpu)
+{
+    int64_t kHz = 0;
+    int rc = RTLinuxSysFsReadIntFile(0, &kHz, "devices/system/cpu/cpu%d/cpufreq/cpuinfo_cur_freq", (int)idCpu);
+    if (RT_FAILURE(rc))
+    {
+        /*
+         * The file may be just unreadable - in that case use plan B, i.e.
+         * /proc/cpuinfo to get the data we want. The assumption is that if
+         * cpuinfo_cur_freq doesn't exist then the speed won't change, and
+         * thus cur == max. If it does exist then cpuinfo contains the
+         * current frequency.
+         */
+        kHz = rtMpLinuxGetFrequency(idCpu) * 1000;
+    }
+    return (kHz + 999) / 1000;
+}
+
+
+RTDECL(uint32_t) RTMpGetMaxFrequency(RTCPUID idCpu)
+{
+    int64_t kHz = 0;
+    int rc = RTLinuxSysFsReadIntFile(0, &kHz, "devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", (int)idCpu);
+    if (RT_FAILURE(rc))
+    {
+        /*
+         * Check if the file isn't there - if it is there, then /proc/cpuinfo
+         * would provide current frequency information, which is wrong.
+         */
+        if (!RTLinuxSysFsExists("devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", (int)idCpu))
+            kHz = rtMpLinuxGetFrequency(idCpu) * 1000;
+        else
+            kHz = 0;
+    }
+    return (kHz + 999) / 1000;
+}
diff --git a/src/VBox/Runtime/r3/linux/rtProcInitExePath-linux.cpp b/src/VBox/Runtime/r3/linux/rtProcInitExePath-linux.cpp
new file mode 100644
index 00000000..bd3edc12
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/rtProcInitExePath-linux.cpp
@@ -0,0 +1,79 @@
+/* $Id: rtProcInitExePath-linux.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, Linux.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <unistd.h>
+#include <errno.h>
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Read the /proc/self/exe link, convert to native and return it.
+     */
+    int cchLink = readlink("/proc/self/exe", pszPath, cchPath - 1);
+    if (cchLink > 0 && (size_t)cchLink <= cchPath - 1)
+    {
+        pszPath[cchLink] = '\0';
+
+        char const *pszTmp;
+        int rc = rtPathFromNative(&pszTmp, pszPath, NULL);
+        AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchLink, pszPath), rc);
+        if (pszTmp != pszPath)
+        {
+            rc = RTStrCopy(pszPath, cchPath, pszTmp);
+            rtPathFreeIprt(pszTmp, pszPath);
+        }
+        return rc;
+    }
+
+    int err = errno;
+    int rc = RTErrConvertFromErrno(err);
+    AssertMsgFailed(("rc=%Rrc err=%d cchLink=%d\n", rc, err, cchLink));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/sched-linux.cpp b/src/VBox/Runtime/r3/linux/sched-linux.cpp
new file mode 100644
index 00000000..0b7370e0
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/sched-linux.cpp
@@ -0,0 +1,707 @@
+/* $Id: sched-linux.cpp $ */
+/** @file
+ * IPRT - Scheduling, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/*
+ * !WARNING!
+ *
+ * When talking about lowering and raising priority, we do *NOT* refer to
+ * the common direction priority values takes on unix systems (lower means
+ * higher). So, when we raise the priority of a linux thread the nice
+ * value will decrease, and when we lower the priority the nice value
+ * will increase. Confusing, right?
+ *
+ * !WARNING!
+ */
+
+
+
+/** @def THREAD_LOGGING
+ * Be very careful with enabling this, it may cause deadlocks when combined
+ * with the 'thread' logging prefix.
+ */
+#ifdef DOXYGEN_RUNNING
+# define THREAD_LOGGING
+#endif
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <errno.h>
+#include <pthread.h>
+#include <limits.h>
+#include <sched.h>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#include <iprt/thread.h>
+#include <iprt/process.h>
+#include <iprt/semaphore.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/log.h>
+#include <iprt/errcore.h>
+#include "internal/sched.h"
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/** Array scheduler attributes corresponding to each of the thread types.
+ * @internal */
+typedef struct PROCPRIORITYTYPE
+{
+    /** For sanity include the array index. */
+    RTTHREADTYPE    enmType;
+    /** The thread priority or nice delta - depends on which priority type. */
+    int             iPriority;
+} PROCPRIORITYTYPE;
+
+
+/**
+ * Configuration of one priority.
+ * @internal
+ */
+typedef struct
+{
+    /** The priority. */
+    RTPROCPRIORITY  enmPriority;
+    /** The name of this priority. */
+    const char     *pszName;
+    /** The process nice value. */
+    int             iNice;
+    /** The delta applied to the iPriority value. */
+    int             iDelta;
+    /** Array scheduler attributes corresponding to each of the thread types. */
+    const PROCPRIORITYTYPE *paTypes;
+} PROCPRIORITY;
+
+
+/**
+ * Saved priority settings
+ * @internal
+ */
+typedef struct
+{
+    /** Process priority. */
+    int                 iPriority;
+    /** Process level. */
+    struct sched_param  SchedParam;
+    /** Process level. */
+    int                 iPolicy;
+    /** pthread level. */
+    struct sched_param  PthreadSchedParam;
+    /** pthread level. */
+    int                 iPthreadPolicy;
+} SAVEDPRIORITY, *PSAVEDPRIORITY;
+
+
+/**
+ * Priorities for checking by separate thread
+ * @internal
+ */
+typedef struct
+{
+    /** The current thread priority to assume first. */
+    int                 iCurrent;
+    /** The thread priority to try set afterwards. */
+    int                 iNew;
+} VALIDATORPRIORITYPAIR, *PVALIDATORPRIORITYPAIR;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Deltas for a process in which we are not restricted
+ * to only be lowering the priority.
+ */
+static const PROCPRIORITYTYPE g_aTypesLinuxFree[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,       +3 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       +2 },
+    { RTTHREADTYPE_EMULATION,               +1 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                 -1 },
+    { RTTHREADTYPE_DEBUGGER,                -1 },
+    { RTTHREADTYPE_MSG_PUMP,                -2 },
+    { RTTHREADTYPE_IO,                      -3 },
+    { RTTHREADTYPE_TIMER,                   -4 }
+};
+
+/**
+ * Deltas for a process in which we are restricted and can only lower the priority.
+ */
+static const PROCPRIORITYTYPE g_aTypesLinuxRestricted[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,       +3 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       +2 },
+    { RTTHREADTYPE_EMULATION,               +1 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                  0 },
+    { RTTHREADTYPE_DEBUGGER,                 0 },
+    { RTTHREADTYPE_MSG_PUMP,                 0 },
+    { RTTHREADTYPE_IO,                       0 },
+    { RTTHREADTYPE_TIMER,                    0 }
+};
+
+/**
+ * All threads have the same priority.
+ *
+ * This is typically chosen when we find that we can't raise the priority
+ * to the process default of a thread created by a low priority thread.
+ */
+static const PROCPRIORITYTYPE g_aTypesLinuxFlat[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,        0 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,        0 },
+    { RTTHREADTYPE_EMULATION,                0 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                  0 },
+    { RTTHREADTYPE_DEBUGGER,                 0 },
+    { RTTHREADTYPE_MSG_PUMP,                 0 },
+    { RTTHREADTYPE_IO,                       0 },
+    { RTTHREADTYPE_TIMER,                    0 }
+};
+
+/**
+ * Process and thread level priority, full access at thread level.
+ */
+static const PROCPRIORITY   g_aUnixConfigs[] =
+{
+    { RTPROCPRIORITY_FLAT,      "Flat",      0,   0, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      19,  19, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesLinuxFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesLinuxRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesLinuxFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesLinuxFlat }
+};
+
+/**
+ * The dynamic default priority configuration.
+ *
+ * This will be recalulated at runtime depending on what the
+ * system allow us to do and what the current priority is.
+ */
+static PROCPRIORITY g_aDefaultPriority =
+{
+    RTPROCPRIORITY_LOW, "Default", 0, 0, g_aTypesLinuxRestricted
+};
+
+/** Pointer to the current priority configuration. */
+static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
+
+/** Set if we can raise the priority of a thread beyond the default.
+ *
+ * It might mean we have the CAP_SYS_NICE capability or that the
+ * process's RLIMIT_NICE is higher than the priority of the thread
+ * calculating the defaults.
+ */
+static bool g_fCanRaisePriority = false;
+
+/** Set if we can restore the priority after having temporarily lowered or raised it. */
+static bool g_fCanRestorePriority = false;
+
+/** Set if we can NOT raise the priority to the process default in a thread
+ * created by a thread running below the process default.
+ */
+static bool g_fScrewedUpMaxPriorityLimitInheritance = true;
+
+/** The highest priority we can set. */
+static int  g_iMaxPriority = 0;
+
+/** The lower priority we can set. */
+static int  g_iMinPriority = 19;
+
+/** Set when we've successfully determined the capabilities of the process and kernel. */
+static bool g_fInitialized = false;
+
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+
+/**
+ * Saves all the scheduling attributes we can think of.
+ */
+static void rtSchedNativeSave(PSAVEDPRIORITY pSave)
+{
+    memset(pSave, 0xff, sizeof(*pSave));
+
+    errno = 0;
+    pSave->iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
+    Assert(errno == 0);
+
+    errno = 0;
+    sched_getparam(0 /* current process */, &pSave->SchedParam);
+    Assert(errno == 0);
+
+    errno = 0;
+    pSave->iPolicy = sched_getscheduler(0 /* current process */);
+    Assert(errno == 0);
+
+    int rc = pthread_getschedparam(pthread_self(), &pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
+    Assert(rc == 0); NOREF(rc);
+}
+
+
+/**
+ * Restores scheduling attributes.
+ * Most of this won't work right, but anyway...
+ */
+static void rtSchedNativeRestore(PSAVEDPRIORITY pSave)
+{
+    setpriority(PRIO_PROCESS, 0, pSave->iPriority);
+    sched_setscheduler(0, pSave->iPolicy, &pSave->SchedParam);
+    sched_setparam(0, &pSave->SchedParam);
+    pthread_setschedparam(pthread_self(), pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
+}
+
+
+/**
+ * Called on the priority proxy thread if requested running, otherwise
+ * rtSchedRunThread() calls it directly.
+ */
+static DECLCALLBACK(int) rtSchedRunThreadCallback(pthread_t *pThread, void *(*pfnThread)(void *pvArg), void *pvArg)
+{
+    int rc = pthread_create(pThread, NULL, pfnThread, pvArg);
+    if (!rc)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(rc);
+}
+
+
+/**
+ * Starts a worker thread and wait for it to complete.
+ *
+ * We cannot use RTThreadCreate since we're already owner of the RW lock.
+ */
+static int rtSchedRunThread(void *(*pfnThread)(void *pvArg), void *pvArg, bool fUsePriorityProxy)
+{
+    /*
+     * Create the thread.
+     */
+    pthread_t Thread;
+    int rc;
+#ifndef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+    RT_NOREF(fUsePriorityProxy);
+#else
+    if (   fUsePriorityProxy
+        && rtThreadPosixPriorityProxyStart())
+        rc = rtThreadPosixPriorityProxyCall(NULL, (PFNRT)rtSchedRunThreadCallback, 3, &Thread, pfnThread, pvArg);
+    else
+#endif
+        rc = rtSchedRunThreadCallback(&Thread, pfnThread, pvArg);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Wait for the thread to finish.
+         */
+        void *pvRet = (void *)-1;
+        do
+        {
+            rc = pthread_join(Thread, &pvRet);
+        } while (rc == EINTR);
+        if (rc)
+            return RTErrConvertFromErrno(rc);
+        return (int)(uintptr_t)pvRet;
+    }
+    return rc;
+}
+
+
+static void rtSchedDumpPriority(void)
+{
+#ifdef THREAD_LOGGING
+    Log(("Priority: g_fCanRaisePriority=%RTbool g_fCanRestorePriority=%RTbool g_fScrewedUpMaxPriorityLimitInheritance=%RTbool\n",
+         g_fCanRaisePriority, g_fCanRestorePriority, g_fScrewedUpMaxPriorityLimitInheritance));
+    Log(("Priority: g_iMaxPriority=%d g_iMinPriority=%d\n", g_iMaxPriority, g_iMinPriority));
+    Log(("Priority: enmPriority=%d \"%s\" iNice=%d iDelta=%d\n",
+         g_pProcessPriority->enmPriority,
+         g_pProcessPriority->pszName,
+         g_pProcessPriority->iNice,
+         g_pProcessPriority->iDelta));
+    Log(("Priority:  %2d INFREQUENT_POLLER = %d\n", RTTHREADTYPE_INFREQUENT_POLLER, g_pProcessPriority->paTypes[RTTHREADTYPE_INFREQUENT_POLLER].iPriority));
+    Log(("Priority:  %2d MAIN_HEAVY_WORKER = %d\n", RTTHREADTYPE_MAIN_HEAVY_WORKER, g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_HEAVY_WORKER].iPriority));
+    Log(("Priority:  %2d EMULATION         = %d\n", RTTHREADTYPE_EMULATION        , g_pProcessPriority->paTypes[RTTHREADTYPE_EMULATION        ].iPriority));
+    Log(("Priority:  %2d DEFAULT           = %d\n", RTTHREADTYPE_DEFAULT          , g_pProcessPriority->paTypes[RTTHREADTYPE_DEFAULT          ].iPriority));
+    Log(("Priority:  %2d GUI               = %d\n", RTTHREADTYPE_GUI              , g_pProcessPriority->paTypes[RTTHREADTYPE_GUI              ].iPriority));
+    Log(("Priority:  %2d MAIN_WORKER       = %d\n", RTTHREADTYPE_MAIN_WORKER      , g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_WORKER      ].iPriority));
+    Log(("Priority:  %2d VRDP_IO           = %d\n", RTTHREADTYPE_VRDP_IO          , g_pProcessPriority->paTypes[RTTHREADTYPE_VRDP_IO          ].iPriority));
+    Log(("Priority:  %2d DEBUGGER          = %d\n", RTTHREADTYPE_DEBUGGER         , g_pProcessPriority->paTypes[RTTHREADTYPE_DEBUGGER         ].iPriority));
+    Log(("Priority:  %2d MSG_PUMP          = %d\n", RTTHREADTYPE_MSG_PUMP         , g_pProcessPriority->paTypes[RTTHREADTYPE_MSG_PUMP         ].iPriority));
+    Log(("Priority:  %2d IO                = %d\n", RTTHREADTYPE_IO               , g_pProcessPriority->paTypes[RTTHREADTYPE_IO               ].iPriority));
+    Log(("Priority:  %2d TIMER             = %d\n", RTTHREADTYPE_TIMER            , g_pProcessPriority->paTypes[RTTHREADTYPE_TIMER            ].iPriority));
+#endif
+}
+
+
+/**
+ * This just checks if it can raise the priority after having been
+ * created by a thread with a low priority.
+ *
+ * @returns zero on success, non-zero on failure.
+ * @param   pvUser  The priority of the parent before it was lowered (cast to int).
+ */
+static void *rtSchedNativeSubProberThread(void *pvUser)
+{
+    int iPriority = getpriority(PRIO_PROCESS, 0);
+    Assert(iPriority == g_iMinPriority);
+
+    if (setpriority(PRIO_PROCESS, 0, iPriority + 1))
+        return (void *)-1;
+    if (setpriority(PRIO_PROCESS, 0, (int)(intptr_t)pvUser))
+        return (void *)-1;
+    return (void *)0;
+}
+
+
+/**
+ * The prober thread.
+ * We don't want to mess with the priority of the calling thread.
+ *
+ * @remark  This is pretty presumptive stuff, but if it works on Linux and
+ *          FreeBSD it does what I want.
+ */
+static void *rtSchedNativeProberThread(void *pvUser)
+{
+    NOREF(pvUser);
+    SAVEDPRIORITY SavedPriority;
+    rtSchedNativeSave(&SavedPriority);
+
+    /*
+     * Check if we can get higher priority (typically only root can do this).
+     * (Won't work right if our priority is -19 to start with, but what the heck.)
+     *
+     * We assume that the priority range is -19 to 19. Should probably find the right
+     * define for this.
+     */
+    int iStart = getpriority(PRIO_PROCESS, 0);
+    int i = iStart;
+    while (i-- > -20)
+        if (setpriority(PRIO_PROCESS, 0, i))
+            break;
+    g_iMaxPriority = getpriority(PRIO_PROCESS, 0);
+    g_fCanRaisePriority = g_iMaxPriority < iStart;
+    g_fCanRestorePriority = setpriority(PRIO_PROCESS, 0, iStart) == 0;
+
+    /*
+     * Check if we temporarily lower the thread priority.
+     * Again, we assume we're not at the extreme end of the priority scale.
+     */
+    iStart = getpriority(PRIO_PROCESS, 0);
+    i = iStart;
+    while (i++ < 19)
+        if (setpriority(PRIO_PROCESS, 0, i))
+            break;
+    g_iMinPriority = getpriority(PRIO_PROCESS, 0);
+    if (    setpriority(PRIO_PROCESS, 0, iStart)
+        ||  getpriority(PRIO_PROCESS, 0) != iStart)
+        g_fCanRestorePriority = false;
+    if (g_iMinPriority == g_iMaxPriority)
+        g_fCanRestorePriority = g_fCanRaisePriority = false;
+
+    /*
+     * Check what happens to child threads when the parent lowers the
+     * priority when it's being created.
+     */
+    iStart = getpriority(PRIO_PROCESS, 0);
+    g_fScrewedUpMaxPriorityLimitInheritance = true;
+    if (    g_fCanRestorePriority
+        &&  !setpriority(PRIO_PROCESS, 0, g_iMinPriority)
+        &&  iStart != g_iMinPriority)
+    {
+        if (rtSchedRunThread(rtSchedNativeSubProberThread, (void *)(intptr_t)iStart, false /*fUsePriorityProxy*/) == 0)
+            g_fScrewedUpMaxPriorityLimitInheritance = false;
+    }
+
+    /* done */
+    rtSchedNativeRestore(&SavedPriority);
+    return (void *)VINF_SUCCESS;
+}
+
+
+/**
+ * Calculate the scheduling properties for all the threads in the default
+ * process priority, assuming the current thread have the type enmType.
+ *
+ * @returns iprt status code.
+ * @param   enmType     The thread type to be assumed for the current thread.
+ */
+DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+
+    /*
+     * First figure out what's we're allowed to do in this process.
+     */
+    if (!g_fInitialized)
+    {
+        int iPriority = getpriority(PRIO_PROCESS, 0);
+#ifdef RLIMIT_RTPRIO
+        /** @todo */
+#endif
+        int rc = rtSchedRunThread(rtSchedNativeProberThread, NULL, false /*fUsePriorityProxy*/);
+        if (RT_FAILURE(rc))
+            return rc;
+        Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
+        g_fInitialized = true;
+    }
+
+    /*
+     * Select the right priority type table and update the default
+     * process priority structure.
+     */
+    if (g_fCanRaisePriority && g_fCanRestorePriority && !g_fScrewedUpMaxPriorityLimitInheritance)
+        g_aDefaultPriority.paTypes = &g_aTypesLinuxFree[0];
+    else if (!g_fCanRaisePriority && g_fCanRestorePriority && !g_fScrewedUpMaxPriorityLimitInheritance)
+        g_aDefaultPriority.paTypes = &g_aTypesLinuxRestricted[0];
+    else
+        g_aDefaultPriority.paTypes = &g_aTypesLinuxFlat[0];
+    Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
+
+    int iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
+    g_aDefaultPriority.iNice = iPriority - g_aDefaultPriority.paTypes[enmType].iPriority;
+    g_aDefaultPriority.iDelta = g_aDefaultPriority.iNice;
+
+    rtSchedDumpPriority();
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The process priority validator thread.
+ * (We don't want to mess with the priority of the calling thread.)
+ */
+static void *rtSchedNativeValidatorThread(void *pvUser)
+{
+    PVALIDATORPRIORITYPAIR pPrioPair = (PVALIDATORPRIORITYPAIR)pvUser;
+    SAVEDPRIORITY SavedPriority;
+    rtSchedNativeSave(&SavedPriority);
+
+    int rc = VINF_SUCCESS;
+
+    /*
+     * Set the priority to the current value for specified thread type, but
+     * only if we have any threads of this type (caller checked - INT_MAX).
+     */
+    if (pPrioPair->iCurrent != INT_MAX)
+        if (setpriority(PRIO_PROCESS, 0, pPrioPair->iCurrent))
+            rc = RTErrConvertFromErrno(errno);
+
+    /*
+     * Try set the new priority.
+     */
+    if (RT_SUCCESS(rc) && setpriority(PRIO_PROCESS, 0, pPrioPair->iNew))
+        rc = RTErrConvertFromErrno(errno);
+
+    /* done */
+    rtSchedNativeRestore(&SavedPriority);
+    return (void *)(intptr_t)rc;
+}
+
+
+/**
+ * Validates the ability to apply suggested priority scheme.
+ *
+ * The function checks that we're able to apply all the thread types in the
+ * suggested priority scheme.
+ *
+ * @returns iprt status code.
+ * @param   pCfg                The priority scheme to validate.
+ * @param   fHavePriorityProxy  Set if we've got a priority proxy thread,
+ *                              otherwise clear.
+ */
+static int rtSchedNativeCheckThreadTypes(const PROCPRIORITY *pCfg, bool fHavePriorityProxy)
+{
+    int i = RTTHREADTYPE_END;
+    while (--i > RTTHREADTYPE_INVALID)
+    {
+        VALIDATORPRIORITYPAIR PrioPair;
+        PrioPair.iCurrent = g_pProcessPriority->paTypes[i].iPriority + g_pProcessPriority->iDelta;
+        PrioPair.iNew     = pCfg->paTypes[i].iPriority               + pCfg->iDelta;
+        if (g_acRTThreadTypeStats[i] == 0)
+            PrioPair.iCurrent = INT_MAX;
+
+#ifdef RT_STRICT
+        int const iPriority = getpriority(PRIO_PROCESS, 0);
+#endif
+        int rc = rtSchedRunThread(rtSchedNativeValidatorThread, &PrioPair, fHavePriorityProxy /*fUsePriorityProxy*/);
+        Assert(getpriority(PRIO_PROCESS, 0) == iPriority);
+
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
+{
+    Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
+
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+    /*
+     * Make sure the proxy creation thread is started so we don't 'lose' our
+     * initial priority if it's lowered.
+     */
+    bool const fHavePriorityProxy = rtThreadPosixPriorityProxyStart();
+#else
+    bool const fHavePriorityProxy = false;
+#endif
+
+    int rc;
+    if (enmPriority == RTPROCPRIORITY_DEFAULT)
+    {
+        /*
+         * If we've lowered priority since the process started, it may be impossible
+         * to raise it again for existing thread (new threads will work fine).
+         */
+        rc = rtSchedNativeCheckThreadTypes(&g_aDefaultPriority, fHavePriorityProxy);
+        if (RT_SUCCESS(rc))
+            g_pProcessPriority = &g_aDefaultPriority;
+    }
+    else
+    {
+        /*
+         * Find a configuration which matches and can be applied.
+         */
+        rc = VERR_NOT_FOUND;
+        for (unsigned i = 0; i < RT_ELEMENTS(g_aUnixConfigs); i++)
+            if (g_aUnixConfigs[i].enmPriority == enmPriority)
+            {
+                int rc2 = rtSchedNativeCheckThreadTypes(&g_aUnixConfigs[i], fHavePriorityProxy);
+                if (RT_SUCCESS(rc2))
+                {
+                    g_pProcessPriority = &g_aUnixConfigs[i];
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+                if (rc == VERR_NOT_FOUND || rc == VERR_ACCESS_DENIED)
+                    rc = rc2;
+            }
+    }
+
+#ifdef THREAD_LOGGING
+    LogFlow(("rtProcNativeSetPriority: returns %Rrc enmPriority=%d\n", rc, enmPriority));
+    rtSchedDumpPriority();
+#endif
+    return rc;
+}
+
+
+/**
+ * Called on the priority proxy thread if it's running, otherwise
+ * rtThreadNativeSetPriority calls it directly.
+ */
+static DECLCALLBACK(int) rtThreadLinuxSetPriorityCallback(PRTTHREADINT pThread, int iPriority)
+{
+    if (!setpriority(PRIO_PROCESS, pThread->tid, iPriority))
+    {
+        AssertMsg(iPriority == getpriority(PRIO_PROCESS, pThread->tid),
+                  ("iPriority=%d getpriority()=%d\n", iPriority, getpriority(PRIO_PROCESS, pThread->tid)));
+#ifdef THREAD_LOGGING
+        Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPriority=%d pid=%d tid=%d\n",
+             pThread->Core.Key, enmType, iPriority, getpid(), pThread->tid));
+#endif
+        return VINF_SUCCESS;
+    }
+    AssertMsgFailed(("setpriority(,, %d) -> errno=%d rc=%Rrc\n", iPriority, errno, RTErrConvertFromErrno(errno)));
+    return VINF_SUCCESS; //non-fatal for now.
+}
+
+
+DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    /* sanity */
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    Assert(enmType == g_pProcessPriority->paTypes[enmType].enmType);
+
+    /*
+     * The thread ID is zero for alien threads, so skip these or we'd risk
+     * modifying our own priority.
+     */
+    if (!pThread->tid)
+        return VINF_SUCCESS;
+
+    /*
+     * Calculate the thread priority and apply it, preferrably via the priority proxy thread.
+     */
+    int const iPriority = g_pProcessPriority->paTypes[enmType].iPriority + g_pProcessPriority->iDelta;
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+    if (rtThreadPosixPriorityProxyStart())
+        return rtThreadPosixPriorityProxyCall(pThread, (PFNRT)rtThreadLinuxSetPriorityCallback, 2, pThread, iPriority);
+#endif
+    return rtThreadLinuxSetPriorityCallback(pThread, iPriority);
+}
+
diff --git a/src/VBox/Runtime/r3/linux/semevent-linux.cpp b/src/VBox/Runtime/r3/linux/semevent-linux.cpp
new file mode 100644
index 00000000..c3a973c1
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/semevent-linux.cpp
@@ -0,0 +1,607 @@
+/* $Id: semevent-linux.cpp $ */
+/** @file
+ * IPRT - Event Semaphore, Linux (2.6.0 and later).
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#include <features.h>
+#if __GLIBC_PREREQ(2,6) && !defined(IPRT_WITH_FUTEX_BASED_SEMS)
+
+/*
+ * glibc 2.6 fixed a serious bug in the mutex implementation. We wrote this
+ * linux specific event semaphores code in order to work around the bug. We
+ * will fall back on the pthread-based implementation if glibc is known to
+ * contain the bug fix.
+ *
+ * The external reference to epoll_pwait is a hack which prevents that we link
+ * against glibc < 2.6.
+ */
+# include "../posix/semevent-posix.cpp"
+__asm__ (".global epoll_pwait");
+
+#else /* glibc < 2.6 */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+#include "internal/mem.h"
+#include "internal/strict.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/syscall.h>
+
+#include "semwait-linux.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Linux (single wakup) event semaphore.
+ */
+struct RTSEMEVENTINTERNAL
+{
+    /** Magic value. */
+    intptr_t volatile   iMagic;
+    /** The futex state variable.
+     * 0 means not signalled.
+       1 means signalled. */
+    uint32_t volatile   fSignalled;
+    /** The number of waiting threads */
+    int32_t volatile    cWaiters;
+#ifdef RTSEMEVENT_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+    /** The creation flags. */
+    uint32_t            fFlags;
+};
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Whether we can use FUTEX_WAIT_BITSET. */
+static int volatile g_fCanUseWaitBitSet = -1;
+
+
+
+
+RTDECL(int)  RTSemEventCreate(PRTSEMEVENT phEventSem)
+{
+    return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
+    Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
+
+    /*
+     * Make sure we know whether FUTEX_WAIT_BITSET works.
+     */
+    rtSemLinuxCheckForFutexWaitBitSet(&g_fCanUseWaitBitSet);
+#if defined(DEBUG_bird) && !defined(IN_GUEST)
+    Assert(g_fCanUseWaitBitSet == true);
+#endif
+
+    /*
+     * Allocate semaphore handle.
+     */
+    struct RTSEMEVENTINTERNAL *pThis;
+    if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        pThis = (struct RTSEMEVENTINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTINTERNAL));
+    else
+        pThis = (struct RTSEMEVENTINTERNAL *)rtMemBaseAlloc(sizeof(struct RTSEMEVENTINTERNAL));
+    if (pThis)
+    {
+        pThis->iMagic     = RTSEMEVENT_MAGIC;
+        pThis->cWaiters   = 0;
+        pThis->fSignalled = 0;
+        pThis->fFlags     = fFlags;
+#ifdef RTSEMEVENT_STRICT
+        if (!pszNameFmt)
+        {
+            static uint32_t volatile s_iSemEventAnon = 0;
+            RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                         true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                         "RTSemEvent-%u", ASMAtomicIncU32(&s_iSemEventAnon) - 1);
+        }
+        else
+        {
+            va_list va;
+            va_start(va, pszNameFmt);
+            RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                          true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                          pszNameFmt, va);
+            va_end(va);
+        }
+        pThis->fEverHadSignallers = false;
+#else
+        RT_NOREF(hClass, pszNameFmt);
+#endif
+
+        *phEventSem = pThis;
+        return VINF_SUCCESS;
+    }
+    return  VERR_NO_MEMORY;
+}
+
+
+RTDECL(int)  RTSemEventDestroy(RTSEMEVENT hEventSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    if (pThis == NIL_RTSEMEVENT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the semaphore and wake up anyone waiting on it.
+     */
+    ASMAtomicXchgSize(&pThis->iMagic, RTSEMEVENT_MAGIC | UINT32_C(0x80000000));
+    if (ASMAtomicXchgS32(&pThis->cWaiters, INT32_MIN / 2) > 0)
+    {
+        sys_futex(&pThis->fSignalled, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
+        usleep(1000);
+    }
+
+    /*
+     * Free the semaphore memory and be gone.
+     */
+#ifdef RTSEMEVENT_STRICT
+    RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+    if (!(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        RTMemFree(pThis);
+    else
+        rtMemBaseFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENT_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    ASMAtomicWriteU32(&pThis->fSignalled, 1);
+    if (ASMAtomicReadS32(&pThis->cWaiters) < 1)
+        return VINF_SUCCESS;
+
+    /* somebody is waiting, try wake up one of them. */
+    long cWoken = sys_futex(&pThis->fSignalled, FUTEX_WAKE, 1, NULL, NULL, 0);
+    if (RT_LIKELY(cWoken >= 0))
+        return VINF_SUCCESS;
+
+    if (RT_UNLIKELY(pThis->iMagic != RTSEMEVENT_MAGIC))
+        return VERR_SEM_DESTROYED;
+
+    return VERR_INVALID_PARAMETER;
+}
+
+
+/**
+ * Performs an indefinite wait on the event.
+ */
+static int rtSemEventLinuxWaitIndefinite(struct RTSEMEVENTINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF_PV(pSrcPos);
+
+    /*
+     * Quickly check whether it's signaled and there are no other waiters.
+     */
+    uint32_t cWaiters = ASMAtomicIncS32(&pThis->cWaiters);
+    if (   cWaiters == 1
+        && ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
+    {
+        ASMAtomicDecS32(&pThis->cWaiters);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * The wait loop.
+     */
+#ifdef RTSEMEVENT_STRICT
+    RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
+                         ? RTThreadSelfAutoAdopt()
+                         : RTThreadSelf();
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+    int rc = VINF_SUCCESS;
+    for (;;)
+    {
+#ifdef RTSEMEVENT_STRICT
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT, true);
+            if (RT_FAILURE(rc))
+                break;
+        }
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
+        long lrc = sys_futex(&pThis->fSignalled, FUTEX_WAIT, 0, NULL /*pTimeout*/, NULL, 0);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
+        if (RT_UNLIKELY(pThis->iMagic != RTSEMEVENT_MAGIC))
+        {
+            rc = VERR_SEM_DESTROYED;
+            break;
+        }
+
+        if (RT_LIKELY(lrc == 0 || lrc == -EWOULDBLOCK))
+        {
+            /* successful wakeup or fSignalled > 0 in the meantime */
+            if (ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
+                break;
+        }
+        else if (lrc == -ETIMEDOUT)
+        {
+            rc = VERR_TIMEOUT;
+            break;
+        }
+        else if (lrc == -EINTR)
+        {
+            if (fFlags & RTSEMWAIT_FLAGS_NORESUME)
+            {
+                rc = VERR_INTERRUPTED;
+                break;
+            }
+        }
+        else
+        {
+            /* this shouldn't happen! */
+            AssertMsgFailed(("rc=%ld errno=%d\n", lrc, errno));
+            rc = RTErrConvertFromErrno(lrc);
+            break;
+        }
+    }
+
+    ASMAtomicDecS32(&pThis->cWaiters);
+    return rc;
+}
+
+
+/**
+ * Handle polling (timeout already expired at the time of the call).
+ *
+ * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED.
+ * @param   pThis               The semaphore.
+ */
+static int rtSemEventLinuxWaitPoll(struct RTSEMEVENTINTERNAL *pThis)
+{
+    /*
+     * What we do here is isn't quite fair to anyone else waiting on it, however
+     * it might not be as bad as all that for callers making repeated poll calls
+     * because they cannot block, as that would be a virtual wait but without the
+     * chance of a permanept queue position.   So, I hope we can live with this.
+     */
+    if (ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
+        return VINF_SUCCESS;
+    return VERR_TIMEOUT;
+}
+
+
+/**
+ * Performs an timed wait on the event.
+ */
+static int rtSemEventLinuxWaitTimed(struct RTSEMEVENTINTERNAL *pThis, uint32_t fFlags,
+                                    uint64_t uTimeout, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF_PV(pSrcPos);
+
+    /*
+     * Convert the timeout value.
+     */
+    struct timespec TsTimeout;
+    int             iWaitOp;
+    uint32_t        uWaitVal3;
+    uint64_t        nsAbsTimeout = uTimeout; /* (older gcc maybe used uninitialized) */
+    uTimeout = rtSemLinuxCalcDeadline(fFlags, uTimeout, g_fCanUseWaitBitSet, &TsTimeout, &iWaitOp, &uWaitVal3, &nsAbsTimeout);
+    if (uTimeout == 0)
+        return rtSemEventLinuxWaitPoll(pThis);
+    if (uTimeout == UINT64_MAX)
+        return rtSemEventLinuxWaitIndefinite(pThis, fFlags, pSrcPos);
+
+    /*
+     * Quickly check whether it's signaled and there are no other waiters.
+     */
+    uint32_t cWaiters = ASMAtomicIncS32(&pThis->cWaiters);
+    if (   cWaiters == 1
+        && ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
+    {
+        ASMAtomicDecS32(&pThis->cWaiters);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * The wait loop.
+     */
+#ifdef RTSEMEVENT_STRICT
+    RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
+                         ? RTThreadSelfAutoAdopt()
+                         : RTThreadSelf();
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+    int rc = VINF_SUCCESS;
+    for (;;)
+    {
+#ifdef RTSEMEVENT_STRICT
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       iWaitOp == FUTEX_WAIT ? uTimeout / RT_NS_1MS : RT_MS_1HOUR /*whatever*/,
+                                                       RTTHREADSTATE_EVENT, true);
+            if (RT_FAILURE(rc))
+                break;
+        }
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
+        long lrc = sys_futex(&pThis->fSignalled, iWaitOp, 0, &TsTimeout, NULL, uWaitVal3);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
+        if (RT_UNLIKELY(pThis->iMagic != RTSEMEVENT_MAGIC))
+        {
+            rc = VERR_SEM_DESTROYED;
+            break;
+        }
+
+        if (RT_LIKELY(lrc == 0 || lrc == -EWOULDBLOCK))
+        {
+            /* successful wakeup or fSignalled > 0 in the meantime */
+            if (ASMAtomicCmpXchgU32(&pThis->fSignalled, 0, 1))
+                break;
+        }
+        else if (lrc == -ETIMEDOUT)
+        {
+#ifdef RT_STRICT
+            uint64_t const uNow = RTTimeNanoTS();
+            AssertMsg(uNow >= nsAbsTimeout || nsAbsTimeout - uNow < RT_NS_1MS,
+                      ("%#RX64 - %#RX64 => %#RX64 (%RI64)\n", nsAbsTimeout, uNow, nsAbsTimeout - uNow, nsAbsTimeout - uNow));
+#endif
+            rc = VERR_TIMEOUT;
+            break;
+        }
+        else if (lrc == -EINTR)
+        {
+            if (fFlags & RTSEMWAIT_FLAGS_NORESUME)
+            {
+                rc = VERR_INTERRUPTED;
+                break;
+            }
+        }
+        else
+        {
+            /* this shouldn't happen! */
+            AssertMsgFailed(("rc=%ld errno=%d\n", lrc, errno));
+            rc = RTErrConvertFromErrno(lrc);
+            break;
+        }
+
+        /* adjust the relative timeout */
+        if (iWaitOp == FUTEX_WAIT)
+        {
+            int64_t i64Diff = nsAbsTimeout - RTTimeSystemNanoTS();
+            if (i64Diff < 1000)
+            {
+                rc = VERR_TIMEOUT;
+                break;
+            }
+            TsTimeout.tv_sec  = (uint64_t)i64Diff / RT_NS_1SEC;
+            TsTimeout.tv_nsec = (uint64_t)i64Diff % RT_NS_1SEC;
+        }
+    }
+
+    ASMAtomicDecS32(&pThis->cWaiters);
+    return rc;
+}
+
+
+/**
+ * Internal wait worker function.
+ */
+DECLINLINE(int) rtSemEventLinuxWait(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->iMagic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+#ifdef RT_STRICT
+    uint32_t const fSignalled = pThis->fSignalled;
+    Assert(fSignalled == false || fSignalled == true);
+#endif
+
+    /*
+     * Timed or indefinite wait?
+     */
+    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
+        return rtSemEventLinuxWaitIndefinite(pThis, fFlags, pSrcPos);
+    return rtSemEventLinuxWaitTimed(hEventSem, fFlags, uTimeout, pSrcPos);
+}
+
+
+RTDECL(int) RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    int rc;
+#ifndef RTSEMEVENT_STRICT
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, NULL);
+    else
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, &SrcPos);
+    else
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, &SrcPos);
+#endif
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    int rc;
+#ifndef RTSEMEVENT_STRICT
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, NULL);
+    else
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, &SrcPos);
+    else
+        rc = rtSemEventLinuxWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, &SrcPos);
+#endif
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+    return rtSemEventLinuxWait(hEventSem, fFlags, uTimeout, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemEventLinuxWait(hEventSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+
+
+RTDECL(int)  RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
+                                   RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemEventLinuxWait(hEventSem, fFlags, uTimeout, &SrcPos);
+}
+
+
+RTDECL(uint32_t) RTSemEventGetResolution(void)
+{
+    /** @todo we have 1ns parameter resolution, but need to verify that this is what
+     *        the kernel actually will use when setting the timer.  Most likely
+     *        it's rounded a little, but hopefully not to a multiple of HZ. */
+    return 1;
+}
+
+
+RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF(hEventSem, hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF(hEventSem, hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->iMagic == RTSEMEVENT_MAGIC);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF(hEventSem, hThread);
+#endif
+}
+
+#endif /* glibc < 2.6 || IPRT_WITH_FUTEX_BASED_SEMS */
+
diff --git a/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp b/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp
new file mode 100644
index 00000000..87554838
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp
@@ -0,0 +1,600 @@
+/* $Id: semeventmulti-linux.cpp $ */
+/** @file
+ * IPRT - Multiple Release Event Semaphore, Linux (2.6.x+).
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+#include <features.h>
+#if __GLIBC_PREREQ(2,6) && !defined(IPRT_WITH_FUTEX_BASED_SEMS)
+
+/*
+ * glibc 2.6 fixed a serious bug in the mutex implementation. We wrote this
+ * linux specific event semaphores code in order to work around the bug. As it
+ * turns out, this code seems to have an unresolved issue (@bugref{2599}), so we'll
+ * fall back on the pthread based implementation if glibc is known to contain
+ * the bug fix.
+ *
+ * The external reference to epoll_pwait is a hack which prevents that we link
+ * against glibc < 2.6.
+ */
+#include "../posix/semeventmulti-posix.cpp"
+__asm__ (".global epoll_pwait");
+
+#else /* glibc < 2.6 */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/asm.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/syscall.h>
+
+#include "semwait-linux.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Linux multiple wakup event semaphore.
+ */
+struct RTSEMEVENTMULTIINTERNAL
+{
+    /** Magic value. */
+    uint32_t volatile   u32Magic;
+    /** The futex state variable, see RTSEMEVENTMULTI_LNX_XXX. */
+    uint32_t volatile   uState;
+#ifdef RT_STRICT
+    /** Increased on every signalling call. */
+    uint32_t volatile   uSignalSerialNo;
+#endif
+#ifdef RTSEMEVENTMULTI_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+};
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @name RTSEMEVENTMULTI_LNX_XXX - state
+ * @{ */
+#define RTSEMEVENTMULTI_LNX_NOT_SIGNALED            UINT32_C(0x00000000)
+#define RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS    UINT32_C(0x00000001)
+#define RTSEMEVENTMULTI_LNX_SIGNALED                UINT32_C(0x00000003)
+/** @} */
+
+#define ASSERT_VALID_STATE(a_uState) \
+    AssertMsg(   (a_uState) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED \
+              || (a_uState) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS \
+              || (a_uState) == RTSEMEVENTMULTI_LNX_SIGNALED, \
+              (#a_uState "=%s\n", a_uState))
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Whether we can use FUTEX_WAIT_BITSET. */
+static int volatile g_fCanUseWaitBitSet = -1;
+
+
+RTDECL(int)  RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem)
+{
+    return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
+                                     const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Make sure we know whether FUTEX_WAIT_BITSET works.
+     */
+    rtSemLinuxCheckForFutexWaitBitSet(&g_fCanUseWaitBitSet);
+#if defined(DEBUG_bird) && !defined(IN_GUEST)
+    Assert(g_fCanUseWaitBitSet == true);
+#endif
+
+    /*
+     * Allocate semaphore handle.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL));
+    if (pThis)
+    {
+        pThis->u32Magic        = RTSEMEVENTMULTI_MAGIC;
+        pThis->uState          = RTSEMEVENTMULTI_LNX_NOT_SIGNALED;
+#ifdef RT_STRICT
+        pThis->uSignalSerialNo = 0;
+#endif
+#ifdef RTSEMEVENTMULTI_STRICT
+        if (!pszNameFmt)
+        {
+            static uint32_t volatile s_iSemEventMultiAnon = 0;
+            RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                         true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                         "RTSemEventMulti-%u", ASMAtomicIncU32(&s_iSemEventMultiAnon) - 1);
+        }
+        else
+        {
+            va_list va;
+            va_start(va, pszNameFmt);
+            RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                          true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                          pszNameFmt, va);
+            va_end(va);
+        }
+        pThis->fEverHadSignallers = false;
+#else
+        RT_NOREF(hClass, pszNameFmt);
+#endif
+
+        *phEventMultiSem = pThis;
+        return VINF_SUCCESS;
+    }
+    return  VERR_NO_MEMORY;
+}
+
+
+RTDECL(int)  RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    if (pThis == NIL_RTSEMEVENTMULTI)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the semaphore and wake up anyone waiting on it.
+     */
+    ASMAtomicWriteU32(&pThis->u32Magic, RTSEMEVENTMULTI_MAGIC + 1);
+    if (ASMAtomicXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_SIGNALED) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS)
+    {
+        sys_futex(&pThis->uState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
+        usleep(1000);
+    }
+
+    /*
+     * Free the semaphore memory and be gone.
+     */
+#ifdef RTSEMEVENTMULTI_STRICT
+    RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENTMULTI_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    /*
+     * Signal it.
+     */
+#ifdef RT_STRICT
+    ASMAtomicIncU32(&pThis->uSignalSerialNo);
+#endif
+    uint32_t uOld = ASMAtomicXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_SIGNALED);
+    if (uOld == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS)
+    {
+        /* wake up sleeping threads. */
+        long cWoken = sys_futex(&pThis->uState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
+        AssertMsg(cWoken >= 0, ("%ld\n", cWoken)); NOREF(cWoken);
+    }
+    ASSERT_VALID_STATE(uOld);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_STRICT
+    uint32_t const uState = pThis->uState;
+    ASSERT_VALID_STATE(uState);
+#endif
+
+    /*
+     * Reset it.
+     */
+    ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED, RTSEMEVENTMULTI_LNX_SIGNALED);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Performs an indefinite wait on the event.
+ */
+static int rtSemEventMultiLinuxWaitIndefinite(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF(pSrcPos);
+
+    /*
+     * Quickly check whether it's signaled.
+     */
+    uint32_t uState = ASMAtomicUoReadU32(&pThis->uState);
+    if (uState == RTSEMEVENTMULTI_LNX_SIGNALED)
+        return VINF_SUCCESS;
+    ASSERT_VALID_STATE(uState);
+
+    /*
+     * The wait loop.
+     */
+#ifdef RTSEMEVENTMULTI_STRICT
+    RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+    for (unsigned i = 0;; i++)
+    {
+        /*
+         * Start waiting. We only account for there being or having been
+         * threads waiting on the semaphore to keep things simple.
+         */
+        uState = ASMAtomicUoReadU32(&pThis->uState);
+        if (   uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS
+            || (   uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED
+                && ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS,
+                                       RTSEMEVENTMULTI_LNX_NOT_SIGNALED)))
+        {
+#ifdef RTSEMEVENTMULTI_STRICT
+            if (pThis->fEverHadSignallers)
+            {
+                int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                                RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT_MULTI, true);
+                if (RT_FAILURE(rc9))
+                    return rc9;
+            }
+#endif
+#ifdef RT_STRICT
+            uint32_t const uPrevSignalSerialNo = ASMAtomicReadU32(&pThis->uSignalSerialNo);
+#endif
+            RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
+            long rc = sys_futex(&pThis->uState, FUTEX_WAIT, 1, NULL /*pTimeout*/, NULL, 0);
+            RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
+
+            /* Check that the structure is still alive before continuing. */
+            if (RT_LIKELY(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC))
+            { /*likely*/ }
+            else
+                return VERR_SEM_DESTROYED;
+
+            /*
+             * Return if success.
+             */
+            if (rc == 0)
+            {
+                Assert(uPrevSignalSerialNo != ASMAtomicReadU32(&pThis->uSignalSerialNo));
+                return VINF_SUCCESS;
+            }
+
+            /*
+             * Act on the wakup code.
+             */
+            if (rc == -EWOULDBLOCK)
+                /* retry, the value changed. */;
+            else if (rc == -EINTR)
+            {
+                if (fFlags & RTSEMWAIT_FLAGS_NORESUME)
+                    return VERR_INTERRUPTED;
+            }
+            else
+            {
+                /* this shouldn't happen! */
+                AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno));
+                return RTErrConvertFromErrno(rc);
+            }
+        }
+        else if (uState == RTSEMEVENTMULTI_LNX_SIGNALED)
+            return VINF_SUCCESS;
+        else
+            ASSERT_VALID_STATE(uState);
+    }
+}
+
+
+/**
+ * Handle polling (timeout already expired at the time of the call).
+ *
+ * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED.
+ * @param   pThis               The semaphore.
+ */
+static int rtSemEventMultiLinuxWaitPoll(struct RTSEMEVENTMULTIINTERNAL *pThis)
+{
+    uint32_t uState = ASMAtomicUoReadU32(&pThis->uState);
+    if (uState == RTSEMEVENTMULTI_LNX_SIGNALED)
+        return VINF_SUCCESS;
+    return VERR_TIMEOUT;
+}
+
+
+/**
+ * Performs an indefinite wait on the event.
+ */
+static int rtSemEventMultiLinuxWaitTimed(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout,
+                                         PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF(pSrcPos);
+
+    /*
+     * Quickly check whether it's signaled.
+     */
+    uint32_t uState = ASMAtomicUoReadU32(&pThis->uState);
+    if (uState == RTSEMEVENTMULTI_LNX_SIGNALED)
+        return VINF_SUCCESS;
+    ASSERT_VALID_STATE(uState);
+
+    /*
+     * Convert the timeout value.
+     */
+    struct timespec TsTimeout;
+    int             iWaitOp;
+    uint32_t        uWaitVal3;
+    uint64_t        nsAbsTimeout = uTimeout; /* (older gcc maybe used uninitialized) */
+    uTimeout = rtSemLinuxCalcDeadline(fFlags, uTimeout, g_fCanUseWaitBitSet, &TsTimeout, &iWaitOp, &uWaitVal3, &nsAbsTimeout);
+    if (uTimeout == 0)
+        return rtSemEventMultiLinuxWaitPoll(pThis);
+    if (uTimeout == UINT64_MAX)
+        return rtSemEventMultiLinuxWaitIndefinite(pThis, fFlags, pSrcPos);
+
+    /*
+     * The wait loop.
+     */
+#ifdef RTSEMEVENTMULTI_STRICT
+    RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+    for (unsigned i = 0;; i++)
+    {
+        /*
+         * Start waiting. We only account for there being or having been
+         * threads waiting on the semaphore to keep things simple.
+         */
+        uState = ASMAtomicUoReadU32(&pThis->uState);
+        if (   uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS
+            || (   uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED
+                && ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS,
+                                       RTSEMEVENTMULTI_LNX_NOT_SIGNALED)))
+        {
+#ifdef RTSEMEVENTMULTI_STRICT
+            if (pThis->fEverHadSignallers)
+            {
+                int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                                uTimeout / UINT32_C(1000000), RTTHREADSTATE_EVENT_MULTI, true);
+                if (RT_FAILURE(rc9))
+                    return rc9;
+            }
+#endif
+#ifdef RT_STRICT
+            uint32_t const uPrevSignalSerialNo = ASMAtomicReadU32(&pThis->uSignalSerialNo);
+#endif
+            RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
+            long rc = sys_futex(&pThis->uState, iWaitOp, 1, &TsTimeout, NULL, uWaitVal3);
+            RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
+
+            /* Check that the structure is still alive before continuing. */
+            if (RT_LIKELY(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC))
+            { /*likely*/ }
+            else
+                return VERR_SEM_DESTROYED;
+
+            /*
+             * Return if success.
+             */
+            if (rc == 0)
+            {
+                Assert(uPrevSignalSerialNo != ASMAtomicReadU32(&pThis->uSignalSerialNo));
+                return VINF_SUCCESS;
+            }
+
+            /*
+             * Act on the wakup code.
+             */
+            if (rc == -ETIMEDOUT)
+            {
+                /** @todo something is broken here. shows up every now and again in the ata
+                 *        code. Should try to run the timeout against RTTimeMilliTS to
+                 *        check that it's doing the right thing... */
+#ifdef RT_STRICT
+                uint64_t const uNow = RTTimeNanoTS();
+                AssertMsg(uNow >= nsAbsTimeout || nsAbsTimeout - uNow < RT_NS_1MS,
+                          ("%#RX64 - %#RX64 => %#RX64 (%RI64)\n", nsAbsTimeout, uNow, nsAbsTimeout - uNow, nsAbsTimeout - uNow));
+#endif
+                return VERR_TIMEOUT;
+            }
+            if (rc == -EWOULDBLOCK)
+            {
+                /* retry, the value changed. */;
+            }
+            else if (rc == -EINTR)
+            {
+                if (fFlags & RTSEMWAIT_FLAGS_NORESUME)
+                    return VERR_INTERRUPTED;
+            }
+            else
+            {
+                /* this shouldn't happen! */
+                AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno));
+                return RTErrConvertFromErrno(rc);
+            }
+        }
+        else if (uState == RTSEMEVENTMULTI_LNX_SIGNALED)
+            return VINF_SUCCESS;
+        else
+            ASSERT_VALID_STATE(uState);
+
+        /* adjust the relative timeout if relative */
+        if (iWaitOp == FUTEX_WAIT)
+        {
+            int64_t i64Diff = nsAbsTimeout - RTTimeSystemNanoTS();
+            if (i64Diff < 1000)
+                return VERR_TIMEOUT;
+            TsTimeout.tv_sec  = (uint64_t)i64Diff / RT_NS_1SEC;
+            TsTimeout.tv_nsec = (uint64_t)i64Diff % RT_NS_1SEC;
+        }
+    }
+}
+
+/**
+ * Internal wait worker function.
+ */
+DECLINLINE(int) rtSemEventLnxMultiWait(RTSEMEVENTMULTI hEventSem, uint32_t fFlags, uint64_t uTimeout, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Timed or indefinite wait?
+     */
+    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
+        return rtSemEventMultiLinuxWaitIndefinite(pThis, fFlags, pSrcPos);
+    return rtSemEventMultiLinuxWaitTimed(hEventSem, fFlags, uTimeout, pSrcPos);
+}
+
+
+#undef RTSemEventMultiWaitEx
+RTDECL(int)  RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+    return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+
+
+RTDECL(int)  RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
+                                        RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+}
+
+
+RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF(hEventMultiSem, hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF(hEventMultiSem, hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF(hEventMultiSem, hThread);
+#endif
+}
+
+#endif /* glibc < 2.6 || IPRT_WITH_FUTEX_BASED_SEMS */
+
diff --git a/src/VBox/Runtime/r3/linux/semmutex-linux.cpp b/src/VBox/Runtime/r3/linux/semmutex-linux.cpp
new file mode 100644
index 00000000..09cd866f
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/semmutex-linux.cpp
@@ -0,0 +1,475 @@
+/* $Id: semmutex-linux.cpp $ */
+/** @file
+ * IPRT - Mutex Semaphore, Linux  (2.6.x+).
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloc.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/syscall.h>
+#if 0 /* With 2.6.17 futex.h has become C++ unfriendly. */
+# include <linux/futex.h>
+#else
+# define FUTEX_WAIT 0
+# define FUTEX_WAKE 1
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Linux internal representation of a Mutex semaphore.
+ */
+struct RTSEMMUTEXINTERNAL
+{
+    /** The futex state variable.
+     * 0 means unlocked.
+     * 1 means locked, no waiters.
+     * 2 means locked, one or more waiters.
+     */
+    int32_t volatile    iState;
+    /** Nesting count. */
+    uint32_t volatile   cNestings;
+    /** The owner of the mutex. */
+    pthread_t volatile  Owner;
+    /** Magic value (RTSEMMUTEX_MAGIC). */
+    uint32_t  volatile  u32Magic;
+#ifdef RTSEMMUTEX_STRICT
+    /** Lock validator record associated with this mutex. */
+    RTLOCKVALRECEXCL    ValidatorRec;
+#endif
+};
+
+
+
+/**
+ * Wrapper for the futex syscall.
+ */
+static long sys_futex(int32_t volatile *uaddr, int op, int val, struct timespec *utime, int32_t *uaddr2, int val3)
+{
+    errno = 0;
+    long rc = syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3);
+    if (rc < 0)
+    {
+        Assert(rc == -1);
+        rc = -errno;
+    }
+    return rc;
+}
+
+
+#undef RTSemMutexCreate
+RTDECL(int)  RTSemMutexCreate(PRTSEMMUTEX phMutexSem)
+{
+    return RTSemMutexCreateEx(phMutexSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+}
+
+
+RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags,
+                               RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate semaphore handle.
+     */
+    struct RTSEMMUTEXINTERNAL *pThis = (struct RTSEMMUTEXINTERNAL *)RTMemAlloc(sizeof(struct RTSEMMUTEXINTERNAL));
+    if (pThis)
+    {
+        pThis->u32Magic     = RTSEMMUTEX_MAGIC;
+        pThis->iState       = 0;
+        pThis->Owner        = (pthread_t)~0;
+        pThis->cNestings    = 0;
+#ifdef RTSEMMUTEX_STRICT
+        if (!pszNameFmt)
+        {
+            static uint32_t volatile s_iMutexAnon = 0;
+            RTLockValidatorRecExclInit(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                       !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL),
+                                       "RTSemMutex-%u", ASMAtomicIncU32(&s_iMutexAnon) - 1);
+        }
+        else
+        {
+            va_list va;
+            va_start(va, pszNameFmt);
+            RTLockValidatorRecExclInitV(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                        !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), pszNameFmt, va);
+            va_end(va);
+        }
+#else
+        RT_NOREF(hClass, uSubClass, pszNameFmt);
+#endif
+
+        *phMutexSem = pThis;
+        return VINF_SUCCESS;
+    }
+
+    return VERR_NO_MEMORY;
+}
+
+
+RTDECL(int)  RTSemMutexDestroy(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate input.
+     */
+    if (hMutexSem == NIL_RTSEMMUTEX)
+        return VINF_SUCCESS;
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC,
+                    ("hMutexSem=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the semaphore and wake up anyone waiting on it.
+     */
+    ASMAtomicWriteU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD);
+    if (ASMAtomicXchgS32(&pThis->iState, 0) > 0)
+    {
+        sys_futex(&pThis->iState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
+        usleep(1000);
+    }
+    pThis->Owner        = (pthread_t)~0;
+    pThis->cNestings    = 0;
+#ifdef RTSEMMUTEX_STRICT
+    RTLockValidatorRecExclDelete(&pThis->ValidatorRec);
+#endif
+
+    /*
+     * Free the semaphore memory and be gone.
+     */
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass)
+{
+#ifdef RTSEMMUTEX_STRICT
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
+
+    return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass);
+#else
+    RT_NOREF(hMutexSem, uSubClass);
+    return RTLOCKVAL_SUB_CLASS_INVALID;
+#endif
+}
+
+
+DECL_FORCE_INLINE(int) rtSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, bool fAutoResume, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF(pSrcPos);
+
+    /*
+     * Validate input.
+     */
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Check if nested request.
+     */
+    pthread_t Self = pthread_self();
+    if (    pThis->Owner == Self
+        &&  pThis->cNestings > 0)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorRec, pSrcPos);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        ASMAtomicIncU32(&pThis->cNestings);
+        return VINF_SUCCESS;
+    }
+
+#ifdef RTSEMMUTEX_STRICT
+    RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+    if (cMillies)
+    {
+        int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorRec, hThreadSelf, pSrcPos, cMillies);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+
+    /*
+     * Convert timeout value.
+     */
+    struct timespec ts;
+    struct timespec *pTimeout = NULL;
+    uint64_t u64End = 0; /* shut up gcc */
+    if (cMillies != RT_INDEFINITE_WAIT)
+    {
+        ts.tv_sec  = cMillies / 1000;
+        ts.tv_nsec = (cMillies % 1000) * UINT32_C(1000000);
+        u64End = RTTimeSystemNanoTS() + cMillies * UINT64_C(1000000);
+        pTimeout = &ts;
+    }
+
+    /*
+     * Lock the mutex.
+     * Optimize for the uncontended case (makes 1-2 ns difference).
+     */
+    if (RT_UNLIKELY(!ASMAtomicCmpXchgS32(&pThis->iState, 1, 0)))
+    {
+        for (;;)
+        {
+            int32_t iOld = ASMAtomicXchgS32(&pThis->iState, 2);
+
+            /*
+             * Was the lock released in the meantime? This is unlikely (but possible)
+             */
+            if (RT_UNLIKELY(iOld == 0))
+                break;
+
+            /*
+             * Go to sleep.
+             */
+            if (pTimeout && ( pTimeout->tv_sec || pTimeout->tv_nsec ))
+            {
+#ifdef RTSEMMUTEX_STRICT
+                int rc9 = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true,
+                                                              cMillies, RTTHREADSTATE_MUTEX, true);
+                if (RT_FAILURE(rc9))
+                    return rc9;
+#else
+                RTThreadBlocking(hThreadSelf, RTTHREADSTATE_MUTEX, true);
+#endif
+            }
+
+            long rc = sys_futex(&pThis->iState, FUTEX_WAIT, 2, pTimeout, NULL, 0);
+
+            RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX);
+            if (RT_UNLIKELY(pThis->u32Magic != RTSEMMUTEX_MAGIC))
+                return VERR_SEM_DESTROYED;
+
+            /*
+             * Act on the wakup code.
+             */
+            if (rc == -ETIMEDOUT)
+            {
+                Assert(pTimeout);
+                return VERR_TIMEOUT;
+            }
+            if (rc == 0)
+                /* we'll leave the loop now unless another thread is faster */;
+            else if (rc == -EWOULDBLOCK)
+                /* retry with new value. */;
+            else if (rc == -EINTR)
+            {
+                if (!fAutoResume)
+                    return VERR_INTERRUPTED;
+            }
+            else
+            {
+                /* this shouldn't happen! */
+                AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno));
+                return RTErrConvertFromErrno(rc);
+            }
+
+            /* adjust the relative timeout */
+            if (pTimeout)
+            {
+                int64_t i64Diff = u64End - RTTimeSystemNanoTS();
+                if (i64Diff < 1000)
+                {
+                    rc = VERR_TIMEOUT;
+                    break;
+                }
+                ts.tv_sec  = (uint64_t)i64Diff / UINT32_C(1000000000);
+                ts.tv_nsec = (uint64_t)i64Diff % UINT32_C(1000000000);
+            }
+        }
+
+        /*
+         * When leaving this loop, iState is set to 2. This means that we gained the
+         * lock and there are _possibly_ some waiters. We don't know exactly as another
+         * thread might entered this loop at nearly the same time. Therefore we will
+         * call futex_wakeup once too often (if _no_ other thread entered this loop).
+         * The key problem is the simple futex_wait test for x != y (iState != 2) in
+         * our case).
+         */
+    }
+
+    /*
+     * Set the owner and nesting.
+     */
+    pThis->Owner = Self;
+    ASMAtomicWriteU32(&pThis->cNestings, 1);
+#ifdef RTSEMMUTEX_STRICT
+    RTLockValidatorRecExclSetOwner(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true);
+#endif
+    return VINF_SUCCESS;
+}
+
+
+#undef RTSemMutexRequest
+RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMMUTEX_STRICT
+    int rc = rtSemMutexRequest(hMutexSem, cMillies, true, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos);
+#endif
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos);
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+#undef RTSemMutexRequestNoResume
+RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMMUTEX_STRICT
+    return rtSemMutexRequest(hMutexSem, cMillies, false, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos);
+}
+
+
+RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMMUTEX_STRICT
+    int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorRec, pThis->cNestings == 1);
+    if (RT_FAILURE(rc9))
+        return rc9;
+#endif
+
+    /*
+     * Check if nested.
+     */
+    pthread_t Self = pthread_self();
+    if (RT_UNLIKELY(    pThis->Owner != Self
+                    ||  pThis->cNestings == 0))
+    {
+        AssertMsgFailed(("Not owner of mutex %p!! Self=%08x Owner=%08x cNestings=%d\n",
+                         pThis, Self, pThis->Owner, pThis->cNestings));
+        return VERR_NOT_OWNER;
+    }
+
+    /*
+     * If nested we'll just pop a nesting.
+     */
+    if (pThis->cNestings > 1)
+    {
+        ASMAtomicDecU32(&pThis->cNestings);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Clear the state. (cNestings == 1)
+     */
+    pThis->Owner = (pthread_t)~0;
+    ASMAtomicWriteU32(&pThis->cNestings, 0);
+
+    /*
+     * Release the mutex.
+     */
+    int32_t iNew = ASMAtomicDecS32(&pThis->iState);
+    if (RT_UNLIKELY(iNew != 0))
+    {
+        /* somebody is waiting, try wake up one of them. */
+        ASMAtomicXchgS32(&pThis->iState, 0);
+        (void)sys_futex(&pThis->iState, FUTEX_WAKE, 1, NULL, NULL, 0);
+    }
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, false);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, false);
+
+    return pThis->Owner != (pthread_t)~0;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/semwait-linux.h b/src/VBox/Runtime/r3/linux/semwait-linux.h
new file mode 100644
index 00000000..0f533845
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/semwait-linux.h
@@ -0,0 +1,233 @@
+/* $Id: semwait-linux.h $ */
+/** @file
+ * IPRT - Common semaphore wait code, Linux.
+ */
+
+/*
+ * Copyright (C) 2021-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_linux_semwait_linux_h
+#define IPRT_INCLUDED_SRC_r3_linux_semwait_linux_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+
+/* With 2.6.17 futex.h has become C++ unfriendly, so define the bits we need. */
+#define FUTEX_WAIT 0
+#define FUTEX_WAKE 1
+#define FUTEX_WAIT_BITSET 9 /**< @since 2.6.25 - uses absolute timeout. */
+
+
+/**
+ * Wrapper for the futex syscall.
+ */
+DECLINLINE(long) sys_futex(uint32_t volatile *uaddr, int op, int val, struct timespec *utime, int32_t *uaddr2, int val3)
+{
+    errno = 0;
+    long rc = syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3);
+    if (rc < 0)
+    {
+        Assert(rc == -1);
+        rc = -errno;
+    }
+    return rc;
+}
+
+
+DECL_NO_INLINE(static, void) rtSemLinuxCheckForFutexWaitBitSetSlow(int volatile *pfCanUseWaitBitSet)
+{
+    uint32_t uTestVar = UINT32_MAX;
+    long rc = sys_futex(&uTestVar, FUTEX_WAIT_BITSET, UINT32_C(0xf0f0f0f0), NULL, NULL, UINT32_MAX);
+    *pfCanUseWaitBitSet = rc == -EAGAIN;
+    AssertMsg(rc == -ENOSYS || rc == -EAGAIN, ("%d\n", rc));
+}
+
+
+DECLINLINE(void) rtSemLinuxCheckForFutexWaitBitSet(int volatile *pfCanUseWaitBitSet)
+{
+    if (*pfCanUseWaitBitSet != -1)
+    { /* likely */ }
+    else
+        rtSemLinuxCheckForFutexWaitBitSetSlow(pfCanUseWaitBitSet);
+}
+
+
+/**
+ * Converts a extended wait timeout specification to an timespec and
+ * corresponding futex operation, as well as an approximate relative nanosecond
+ * interval.
+ *
+ * @note    This does not check for RTSEMWAIT_FLAGS_INDEFINITE, caller should've
+ *          done that already.
+ *
+ * @returns The relative wait in nanoseconds.  0 for a poll call, UINT64_MAX for
+ *          an effectively indefinite wait.
+ * @param   fFlags              RTSEMWAIT_FLAGS_XXX.
+ * @param   fCanUseWaitBitSet   Whether we can use FUTEX_WAIT_BITMSET or not.
+ * @param   uTimeout            The timeout.
+ * @param   pDeadline           Where to return the deadline.
+ * @param   piWaitOp            Where to return the FUTEX wait operation number.
+ * @param   puWaitVal3          Where to return the FUTEX wait value 3.
+ * @param   pnsAbsTimeout       Where to return the absolute timeout in case of
+ *                              a resuming relative call (i.e. FUTEX_WAIT).
+ */
+DECL_FORCE_INLINE(uint64_t)
+rtSemLinuxCalcDeadline(uint32_t fFlags, uint64_t uTimeout, int fCanUseWaitBitSet,
+                       struct timespec *pDeadline, int *piWaitOp, uint32_t *puWaitVal3, uint64_t *pnsAbsTimeout)
+{
+    Assert(!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE));
+
+    if (fFlags & RTSEMWAIT_FLAGS_RELATIVE)
+    {
+        Assert(!(fFlags & RTSEMWAIT_FLAGS_ABSOLUTE));
+
+        /*
+         * Polling call?
+         */
+        if (uTimeout == 0)
+            return 0;
+
+        /*
+         * We use FUTEX_WAIT here as it takes a relative timespec.
+         *
+         * Note! For non-resuming waits, we can skip calculating the absolute
+         *       time ASSUMING it is only needed for timeout adjustments
+         *       after an -EINTR return.
+         */
+        if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
+        {
+            if (   sizeof(pDeadline->tv_sec) >= sizeof(uint64_t)
+                || uTimeout < (uint64_t)UINT32_MAX * RT_MS_1SEC)
+            {
+                pDeadline->tv_sec  = uTimeout / RT_MS_1SEC;
+                pDeadline->tv_nsec = (uTimeout % RT_MS_1SEC) & RT_NS_1MS;
+                uTimeout *= RT_NS_1MS;
+            }
+            else
+                return UINT64_MAX;
+        }
+        else
+        {
+            Assert(fFlags & RTSEMWAIT_FLAGS_NANOSECS);
+            if (   sizeof(pDeadline->tv_sec) >= sizeof(uint64_t)
+                || uTimeout < (uint64_t)UINT32_MAX * RT_NS_1SEC)
+            {
+                pDeadline->tv_sec  = uTimeout / RT_NS_1SEC;
+                pDeadline->tv_nsec = uTimeout % RT_NS_1SEC;
+            }
+            else
+                return UINT64_MAX;
+        }
+
+#ifdef RT_STRICT
+        if (!(fFlags & RTSEMWAIT_FLAGS_RESUME))
+            *pnsAbsTimeout = uTimeout;
+        else
+#endif
+            *pnsAbsTimeout = RTTimeNanoTS() + uTimeout; /* Note! only relevant for relative waits (FUTEX_WAIT). */
+    }
+    else
+    {
+        /* Absolute deadline: */
+        Assert(fFlags & RTSEMWAIT_FLAGS_ABSOLUTE);
+        if (fCanUseWaitBitSet == true)
+        {
+            /*
+             * Use FUTEX_WAIT_BITSET as it takes an absolute deadline.
+             */
+            if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
+            {
+                if (   sizeof(pDeadline->tv_sec) >= sizeof(uint64_t)
+                    || uTimeout < (uint64_t)UINT32_MAX * RT_MS_1SEC)
+                {
+                    pDeadline->tv_sec  = uTimeout / RT_MS_1SEC;
+                    pDeadline->tv_nsec = (uTimeout % RT_MS_1SEC) & RT_NS_1MS;
+                }
+                else
+                    return UINT64_MAX;
+            }
+            else
+            {
+                Assert(fFlags & RTSEMWAIT_FLAGS_NANOSECS);
+                if (   sizeof(pDeadline->tv_sec) >= sizeof(uint64_t)
+                    || uTimeout < (uint64_t)UINT32_MAX * RT_NS_1SEC)
+                {
+                    pDeadline->tv_sec  = uTimeout / RT_NS_1SEC;
+                    pDeadline->tv_nsec = uTimeout % RT_NS_1SEC;
+                }
+                else
+                    return UINT64_MAX;
+            }
+            *pnsAbsTimeout = uTimeout;
+            *piWaitOp      = FUTEX_WAIT_BITSET;
+            *puWaitVal3    = UINT32_MAX;
+            return RT_MS_1SEC; /* Whatever non-zero; Whole point is not calling RTTimeNanoTS() in this path. */
+        }
+
+        /*
+         * FUTEX_WAIT_BITSET is not available, so use FUTEX_WAIT with a
+         * relative timeout.
+         */
+        if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
+        {
+            if (uTimeout < UINT64_MAX / RT_NS_1MS)
+                uTimeout *= RT_NS_1MS;
+            else
+                return UINT64_MAX;
+        }
+
+        uint64_t const u64Now = RTTimeNanoTS();
+        if (u64Now < uTimeout)
+        {
+            *pnsAbsTimeout = uTimeout;
+            uTimeout      -= u64Now;
+        }
+        else
+            return 0;
+
+        if (   sizeof(pDeadline->tv_sec) >= sizeof(uint64_t)
+            || uTimeout < (uint64_t)UINT32_MAX * RT_NS_1SEC)
+        {
+            pDeadline->tv_sec  = uTimeout / RT_NS_1SEC;
+            pDeadline->tv_nsec = uTimeout % RT_NS_1SEC;
+        }
+        else
+            return UINT64_MAX;
+    }
+
+    *piWaitOp   = FUTEX_WAIT;
+    *puWaitVal3 = 0;
+    return uTimeout;
+}
+
+#endif /* !IPRT_INCLUDED_SRC_r3_linux_semwait_linux_h */
+
diff --git a/src/VBox/Runtime/r3/linux/sysfs.cpp b/src/VBox/Runtime/r3/linux/sysfs.cpp
new file mode 100644
index 00000000..6324fe00
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/sysfs.cpp
@@ -0,0 +1,736 @@
+/* $Id: sysfs.cpp $ */
+/** @file
+ * IPRT - Linux sysfs access.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/assert.h>
+#include <iprt/dir.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/fs.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/symlink.h>
+
+#include <iprt/linux/sysfs.h>
+
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/fcntl.h>
+#include <sys/sysmacros.h>
+#include <errno.h>
+
+
+
+/**
+ * Constructs the path of a sysfs file from the format parameters passed,
+ * prepending a prefix if the path is relative.
+ *
+ * @returns IPRT status code.
+ * @param   pszPrefix  The prefix to prepend if the path is relative.  Must end
+ *                     in '/'.
+ * @param   pszBuf     Where to write the path.  Must be at least
+ *                     sizeof(@a pszPrefix) characters long
+ * @param   cchBuf     The size of the buffer pointed to by @a pszBuf.
+ * @param   pszFormat  The name format, either absolute or relative to the
+ *                     prefix specified by @a pszPrefix.
+ * @param   va         The format args.
+ */
+static int rtLinuxConstructPathV(char *pszBuf, size_t cchBuf,
+                                 const char *pszPrefix,
+                                 const char *pszFormat, va_list va)
+{
+    size_t const cchPrefix = strlen(pszPrefix);
+    AssertReturn(pszPrefix[cchPrefix - 1] == '/', VERR_INVALID_PARAMETER);
+    AssertReturn(cchBuf > cchPrefix + 1, VERR_INVALID_PARAMETER);
+
+    ssize_t cch = RTStrPrintf2V(pszBuf, cchBuf, pszFormat, va);
+    AssertReturn(cch >= 0, VERR_BUFFER_OVERFLOW);
+
+    if (*pszBuf != '/')
+    {
+        AssertReturn(cchBuf >= (size_t)cch + cchPrefix + 1, VERR_BUFFER_OVERFLOW);
+        memmove(pszBuf + cchPrefix, pszBuf, (size_t)cch + 1);
+        memcpy(pszBuf, pszPrefix, cchPrefix);
+    }
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Constructs the path of a sysfs file from the format parameters passed,
+ * prepending a prefix if the path is relative.
+ *
+ * @returns IPRT status code.
+ * @param   pszPrefix  The prefix to prepend if the path is relative.  Must end
+ *                     in '/'.
+ * @param   pszBuf     Where to write the path.  Must be at least
+ *                     sizeof(@a pszPrefix) characters long
+ * @param   cchBuf     The size of the buffer pointed to by @a pszBuf.
+ * @param   pszFormat  The name format, either absolute or relative to "/sys/".
+ * @param   ...        The format args.
+ */
+DECLINLINE(int) rtLinuxConstructPath(char *pszBuf, size_t cchBuf,
+                                     const char *pszPrefix,
+                                     const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = rtLinuxConstructPathV(pszBuf, cchBuf, pszPrefix, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+/**
+ * Constructs the path of a sysfs file from the format parameters passed,
+ * prepending "/sys/" if the path is relative.
+ *
+ * @returns IPRT status code.
+ * @param   pszBuf     Where to write the path.  Must be at least
+ *                     sizeof("/sys/") characters long
+ * @param   cchBuf     The size of the buffer pointed to by @a pszBuf.
+ * @param   pszFormat  The name format, either absolute or relative to "/sys/".
+ * @param   va         The format args.
+ */
+DECLINLINE(int) rtLinuxSysFsConstructPath(char *pszBuf, size_t cchBuf, const char *pszFormat, va_list va)
+{
+    return rtLinuxConstructPathV(pszBuf, cchBuf, "/sys/", pszFormat, va);
+}
+
+
+RTDECL(int) RTLinuxConstructPathV(char *pszPath, size_t cbPath, const char *pszFormat, va_list va)
+{
+    return rtLinuxSysFsConstructPath(pszPath, cbPath, pszFormat, va);
+}
+
+
+RTDECL(int) RTLinuxConstructPath(char *pszPath, size_t cbPath, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = rtLinuxSysFsConstructPath(pszPath, cbPath, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsExistsExV(const char *pszFormat, va_list va)
+{
+    int iSavedErrno = errno;
+
+    /*
+     * Construct the filename and call stat.
+     */
+    char szFilename[RTPATH_MAX];
+    int rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat st;
+        int rcStat = stat(szFilename, &st);
+        if (rcStat != 0)
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    errno = iSavedErrno;
+    return rc;
+}
+
+
+RTDECL(bool) RTLinuxSysFsExistsV(const char *pszFormat, va_list va)
+{
+    return RT_SUCCESS(RTLinuxSysFsExistsExV(pszFormat, va));
+}
+
+
+RTDECL(int) RTLinuxSysFsExistsEx(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsExistsExV(pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(bool) RTLinuxSysFsExists(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    bool fRet = RTLinuxSysFsExistsV(pszFormat, va);
+    va_end(va);
+    return fRet;
+}
+
+
+RTDECL(int) RTLinuxSysFsOpenV(PRTFILE phFile, const char *pszFormat, va_list va)
+{
+    /*
+     * Construct the filename and call open.
+     */
+    char szFilename[RTPATH_MAX];
+    int rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va);
+    if (RT_SUCCESS(rc))
+        rc = RTFileOpen(phFile, szFilename, RTFILE_O_OPEN | RTFILE_O_READ | RTFILE_O_DENY_NONE);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsOpenExV(PRTFILE phFile, uint64_t fOpen, const char *pszFormat, va_list va)
+{
+    /*
+     * Construct the filename and call open.
+     */
+    char szFilename[RTPATH_MAX];
+    int rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va);
+    if (RT_SUCCESS(rc))
+        rc = RTFileOpen(phFile, szFilename, fOpen);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsOpen(PRTFILE phFile, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsOpenV(phFile, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsOpenEx(PRTFILE phFile, uint64_t fOpen, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsOpenExV(phFile, fOpen, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadStr(RTFILE hFile, char *pszBuf, size_t cchBuf, size_t *pcchRead)
+{
+    Assert(cchBuf > 1); /* not mandatory */
+
+    int rc;
+    size_t cchRead;
+    rc = RTFileRead(hFile, pszBuf, cchBuf, &cchRead);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * ASSUME that if we've read less than we asked for, we've reached the
+         * end of the file.  Otherwise, we've been given a buffer too small for
+         * the entire remainder of the file.
+         */
+        if (cchRead < cchBuf)
+            pszBuf[cchRead] = '\0';
+        else if (cchBuf)
+        {
+            rc = RTFileSeek(hFile, -1, RTFILE_SEEK_CURRENT, NULL);
+            if (RT_SUCCESS(rc))
+                rc = VERR_BUFFER_OVERFLOW;
+            cchRead = cchBuf - 1;
+            pszBuf[cchRead] = '\0';
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+    else
+    {
+        if (cchBuf > 0)
+            *pszBuf = '\0';
+        cchRead = 0;
+    }
+
+    if (pcchRead)
+        *pcchRead = cchRead;
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteStr(RTFILE hFile, const char *pszBuf, size_t cchBuf, size_t *pcchWritten)
+{
+    if (!cchBuf)
+        cchBuf = strlen(pszBuf) + 1; /* Include the terminator */
+    return RTFileWrite(hFile, pszBuf, cchBuf, pcchWritten);
+}
+
+
+RTDECL(int) RTLinuxSysFsReadFile(RTFILE hFile, void *pvBuf, size_t cbBuf, size_t *pcbRead)
+{
+    int    rc;
+    size_t cbRead = 0;
+
+    rc = RTFileRead(hFile, pvBuf, cbBuf, &cbRead);
+    if (RT_SUCCESS(rc))
+    {
+        if (pcbRead)
+            *pcbRead = cbRead;
+        if (cbRead < cbBuf)
+            rc = VINF_SUCCESS;
+        else
+        {
+            /* Check for EOF */
+            uint64_t offCur = 0;
+            uint8_t bRead;
+            rc = RTFileSeek(hFile, 0, RTFILE_SEEK_CURRENT, &offCur);
+            if (RT_SUCCESS(rc))
+            {
+                int rc2 = RTFileRead(hFile, &bRead, 1, NULL);
+                if (RT_SUCCESS(rc2))
+                {
+                    rc = VERR_BUFFER_OVERFLOW;
+
+                    rc2 = RTFileSeek(hFile, offCur, RTFILE_SEEK_BEGIN, NULL);
+                    if (RT_FAILURE(rc2))
+                        rc = rc2;
+                }
+                else if (rc2 != VERR_EOF)
+                    rc = rc2;
+            }
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteFile(RTFILE hFile, void *pvBuf, size_t cbBuf, size_t *pcbWritten)
+{
+    return RTFileWrite(hFile, pvBuf, cbBuf, pcbWritten);
+}
+
+
+RTDECL(int) RTLinuxSysFsReadIntFileV(unsigned uBase, int64_t *pi64, const char *pszFormat, va_list va)
+{
+    RTFILE hFile;
+
+    AssertPtrReturn(pi64, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsOpenV(&hFile, pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        char szNum[128];
+        size_t cchNum;
+        rc = RTLinuxSysFsReadStr(hFile, szNum, sizeof(szNum), &cchNum);
+        if (RT_SUCCESS(rc))
+        {
+            if (cchNum > 0)
+            {
+                int64_t i64Ret = -1;
+                rc = RTStrToInt64Ex(szNum, NULL, uBase, &i64Ret);
+                if (RT_SUCCESS(rc))
+                    *pi64 = i64Ret;
+            }
+            else
+                rc = VERR_INVALID_PARAMETER;
+        }
+
+        RTFileClose(hFile);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadIntFile(unsigned uBase, int64_t *pi64, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsReadIntFileV(uBase, pi64, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU8FileV(unsigned uBase, uint8_t u8, const char *pszFormat, va_list va)
+{
+    return RTLinuxSysFsWriteU64FileV(uBase, u8, pszFormat, va);
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU8File(unsigned uBase, uint8_t u8, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsWriteU64FileV(uBase, u8, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU16FileV(unsigned uBase, uint16_t u16, const char *pszFormat, va_list va)
+{
+    return RTLinuxSysFsWriteU64FileV(uBase, u16, pszFormat, va);
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU16File(unsigned uBase, uint16_t u16, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsWriteU64FileV(uBase, u16, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU32FileV(unsigned uBase, uint32_t u32, const char *pszFormat, va_list va)
+{
+    return RTLinuxSysFsWriteU64FileV(uBase, u32, pszFormat, va);
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU32File(unsigned uBase, uint32_t u32, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsWriteU64FileV(uBase, u32, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU64FileV(unsigned uBase, uint64_t u64, const char *pszFormat, va_list va)
+{
+    RTFILE hFile;
+
+    const char *pszFmt = NULL;
+    switch (uBase)
+    {
+        case 8:
+            pszFmt = "%#llo";
+            break;
+        case 10:
+            pszFmt = "%llu";
+            break;
+        case 16:
+            pszFmt = "%#llx";
+            break;
+        default:
+            return VERR_INVALID_PARAMETER;
+    }
+
+    int rc = RTLinuxSysFsOpenExV(&hFile, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE, pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        char szNum[128];
+        size_t cchNum = RTStrPrintf(szNum, sizeof(szNum), pszFmt, u64);
+        if (cchNum > 0)
+        {
+            size_t cbWritten = 0;
+            rc = RTLinuxSysFsWriteStr(hFile, &szNum[0], cchNum, &cbWritten);
+            if (   RT_SUCCESS(rc)
+                && cbWritten != cchNum)
+                rc = VERR_BUFFER_OVERFLOW;
+        }
+        else
+            rc = VERR_INVALID_PARAMETER;
+
+        RTFileClose(hFile);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteU64File(unsigned uBase, uint32_t u64, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsWriteU64FileV(uBase, u64, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadDevNumFileV(dev_t *pDevNum, const char *pszFormat, va_list va)
+{
+    RTFILE hFile;
+
+    AssertPtrReturn(pDevNum, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsOpenV(&hFile, pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cchNum = 0;
+        char szNum[128];
+        rc = RTLinuxSysFsReadStr(hFile, szNum, sizeof(szNum), &cchNum);
+        if (RT_SUCCESS(rc))
+        {
+            if (cchNum > 0)
+            {
+                uint32_t u32Maj = 0;
+                uint32_t u32Min = 0;
+                char *pszNext = NULL;
+                rc = RTStrToUInt32Ex(szNum, &pszNext, 10, &u32Maj);
+                if (RT_FAILURE(rc) || (rc != VWRN_TRAILING_CHARS) || (*pszNext != ':'))
+                    rc = VERR_INVALID_PARAMETER;
+                else
+                {
+                    rc = RTStrToUInt32Ex(pszNext + 1, NULL, 10, &u32Min);
+                    if (   rc != VINF_SUCCESS
+                        && rc != VWRN_TRAILING_CHARS
+                        && rc != VWRN_TRAILING_SPACES)
+                        rc = VERR_INVALID_PARAMETER;
+                    else
+                        *pDevNum = makedev(u32Maj, u32Min);
+                }
+            }
+            else
+                rc = VERR_INVALID_PARAMETER;
+        }
+
+        RTFileClose(hFile);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadDevNumFile(dev_t *pDevNum, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsReadDevNumFileV(pDevNum, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadStrFileV(char *pszBuf, size_t cchBuf, size_t *pcchRead, const char *pszFormat, va_list va)
+{
+    RTFILE hFile;
+
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsOpenV(&hFile, pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Note! We cannot use RTLinuxSysFsReadStr here as it has different
+         *       semantics wrt to newline characters.  It is not known why
+         *       the semantics has to differ... Michael, any clues?
+         */
+        size_t cchRead;
+        rc = RTFileRead(hFile, pszBuf, cchBuf, &cchRead);
+        if (RT_SUCCESS(rc))
+        {
+            char *pchNewLine = (char *)memchr(pszBuf, '\n', cchRead);
+            if (pchNewLine)
+            {
+                *pchNewLine = '\0';
+                cchRead = pchNewLine - pszBuf;
+            }
+            else if (cchRead < cchBuf)
+                pszBuf[cchRead] = '\0';
+            else
+            {
+                if (cchBuf)
+                {
+                    cchRead = cchBuf - 1;
+                    pszBuf[cchRead] = '\0';
+                }
+                else
+                    cchRead = 0;
+                rc = VERR_BUFFER_OVERFLOW;
+            }
+        }
+        else
+            cchRead = 0;
+
+        RTFileClose(hFile);
+
+        if (pcchRead)
+            *pcchRead = cchRead;
+    }
+    else
+    {
+        if (cchBuf)
+            *pszBuf = '\0';
+        if (pcchRead)
+            *pcchRead = 0;
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsReadStrFile(char *pszBuf, size_t cchBuf, size_t *pcchRead, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsReadStrFileV(pszBuf, cchBuf, pcchRead, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteStrFileV(const char *pszBuf, size_t cchBuf, size_t *pcchWritten, const char *pszFormat, va_list va)
+{
+    RTFILE hFile;
+
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+
+    int rc = RTLinuxSysFsOpenExV(&hFile, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE, pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTLinuxSysFsWriteStr(hFile, pszBuf, cchBuf, pcchWritten);
+        RTFileClose(hFile);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsWriteStrFile(const char *pszBuf, size_t cchBuf, size_t *pcchWritten, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsWriteStrFileV(pszBuf, cchBuf, pcchWritten, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+RTDECL(int) RTLinuxSysFsGetLinkDestV(char *pszBuf, size_t cchBuf, size_t *pchBuf, const char *pszFormat, va_list va)
+{
+    AssertReturn(cchBuf >= 2, VERR_INVALID_PARAMETER);
+
+    /*
+     * Construct the filename and read the link.
+     */
+    char szFilename[RTPATH_MAX];
+    int rc = rtLinuxSysFsConstructPath(szFilename, sizeof(szFilename), pszFormat, va);
+    if (RT_SUCCESS(rc))
+    {
+        char szLink[RTPATH_MAX];
+        rc = RTSymlinkRead(szFilename, szLink, sizeof(szLink), 0);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Extract the file name component and copy it into the return buffer.
+             */
+            size_t cchName;
+            const char *pszName = RTPathFilename(szLink);
+            if (pszName)
+            {
+                cchName = strlen(pszName);
+                if (cchName < cchBuf)
+                    memcpy(pszBuf, pszName, cchName + 1);
+                else
+                    rc = VERR_BUFFER_OVERFLOW;
+            }
+            else
+            {
+                *pszBuf = '\0';
+                cchName = 0;
+            }
+
+            if (pchBuf)
+                *pchBuf = cchName;
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxSysFsGetLinkDest(char *pszBuf, size_t cchBuf, size_t *pchBuf, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTLinuxSysFsGetLinkDestV(pszBuf, cchBuf, pchBuf, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxCheckDevicePathV(dev_t DevNum, RTFMODE fMode, char *pszBuf,
+                                    size_t cchBuf, const char *pszPattern,
+                                    va_list va)
+{
+    AssertReturn(cchBuf >= 2, VERR_INVALID_PARAMETER);
+    AssertReturn(   fMode == RTFS_TYPE_DEV_CHAR
+                 || fMode == RTFS_TYPE_DEV_BLOCK,
+                 VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszPattern, VERR_INVALID_PARAMETER);
+
+    /*
+     * Construct the filename and read the link.
+     */
+    char szFilename[RTPATH_MAX];
+    int rc = rtLinuxConstructPathV(szFilename, sizeof(szFilename), "/dev/",
+                                   pszPattern, va);
+    if (RT_SUCCESS(rc))
+    {
+        RTFSOBJINFO Info;
+        rc = RTPathQueryInfo(szFilename, &Info, RTFSOBJATTRADD_UNIX);
+        if (   rc == VERR_PATH_NOT_FOUND
+            || (   RT_SUCCESS(rc)
+                && (   Info.Attr.u.Unix.Device != DevNum
+                    || (Info.Attr.fMode & RTFS_TYPE_MASK) != fMode)))
+            rc = VERR_FILE_NOT_FOUND;
+
+        if (RT_SUCCESS(rc))
+        {
+            size_t cchPath = strlen(szFilename);
+            if (cchPath < cchBuf)
+                memcpy(pszBuf, szFilename, cchPath + 1);
+            else
+                rc = VERR_BUFFER_OVERFLOW;
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLinuxCheckDevicePath(dev_t DevNum, RTFMODE fMode, char *pszBuf,
+                                   size_t cchBuf, const char *pszPattern,
+                                   ...)
+{
+    va_list va;
+    va_start(va, pszPattern);
+    int rc = RTLinuxCheckDevicePathV(DevNum, fMode, pszBuf, cchBuf,
+                                     pszPattern, va);
+    va_end(va);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/systemmem-linux.cpp b/src/VBox/Runtime/r3/linux/systemmem-linux.cpp
new file mode 100644
index 00000000..11764ab7
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/systemmem-linux.cpp
@@ -0,0 +1,119 @@
+/* $Id: systemmem-linux.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, Linux ring-3.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+#include <stdio.h>
+#include <errno.h>
+
+/* Satisfy compiller warning */
+#define __EXPORTED_HEADERS__
+#include <sys/sysinfo.h>
+#undef __EXPORTED_HEADERS__
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    struct sysinfo info;
+    int rc = sysinfo(&info);
+    if (rc == 0)
+    {
+        *pcb = (uint64_t)info.totalram * info.mem_unit;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    FILE *pFile = fopen("/proc/meminfo", "r");
+    if (pFile)
+    {
+        int rc = VERR_NOT_FOUND;
+        uint64_t cbTotal = 0;
+        uint64_t cbFree = 0;
+        uint64_t cbBuffers = 0;
+        uint64_t cbCached = 0;
+        char sz[256];
+        while (fgets(sz, sizeof(sz), pFile))
+        {
+            if (!strncmp(sz, RT_STR_TUPLE("MemTotal:")))
+                rc = RTStrToUInt64Ex(RTStrStripL(&sz[sizeof("MemTotal:")]), NULL, 0, &cbTotal);
+            else if (!strncmp(sz, RT_STR_TUPLE("MemFree:")))
+                rc = RTStrToUInt64Ex(RTStrStripL(&sz[sizeof("MemFree:")]), NULL, 0, &cbFree);
+            else if (!strncmp(sz, RT_STR_TUPLE("Buffers:")))
+                rc = RTStrToUInt64Ex(RTStrStripL(&sz[sizeof("Buffers:")]), NULL, 0, &cbBuffers);
+            else if (!strncmp(sz, RT_STR_TUPLE("Cached:")))
+                rc = RTStrToUInt64Ex(RTStrStripL(&sz[sizeof("Cached:")]), NULL, 0, &cbCached);
+            if (RT_FAILURE(rc))
+                break;
+        }
+        fclose(pFile);
+        if (RT_SUCCESS(rc))
+        {
+            *pcb = (cbFree + cbBuffers + cbCached) * _1K;
+            return VINF_SUCCESS;
+        }
+    }
+    /*
+     * Fallback (e.g. /proc not mapped) to sysinfo. Less accurat because there
+     * is no information about the cached memory. 'Cached:' from above is only
+     * accessible through proc :-(
+     */
+    struct sysinfo info;
+    int rc = sysinfo(&info);
+    if (rc == 0)
+    {
+        *pcb = ((uint64_t)info.freeram + info.bufferram) * info.mem_unit;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
diff --git a/src/VBox/Runtime/r3/linux/thread-affinity-linux.cpp b/src/VBox/Runtime/r3/linux/thread-affinity-linux.cpp
new file mode 100644
index 00000000..2726e716
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/thread-affinity-linux.cpp
@@ -0,0 +1,105 @@
+/* $Id: thread-affinity-linux.cpp $ */
+/** @file
+ * IPRT - Thread Affinity, Linux ring-3 implementation.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
+#include <features.h>
+#if __GLIBC_PREREQ(2,4)
+
+#include <sched.h>
+#include <unistd.h>
+#include <errno.h>
+#include <pthread.h>
+
+#include <iprt/thread.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/cpuset.h>
+#include <iprt/err.h>
+#include <iprt/mp.h>
+
+
+
+RTR3DECL(int) RTThreadSetAffinity(PCRTCPUSET pCpuSet)
+{
+    /* convert */
+    cpu_set_t LnxCpuSet;
+    CPU_ZERO(&LnxCpuSet);
+    if (!pCpuSet)
+        for (unsigned iCpu = 0; iCpu < CPU_SETSIZE; iCpu++)
+            CPU_SET(iCpu, &LnxCpuSet);
+    else
+        for (unsigned iCpu = 0; iCpu < RT_MIN(CPU_SETSIZE, RTCPUSET_MAX_CPUS); iCpu++)
+            if (RTCpuSetIsMemberByIndex(pCpuSet, iCpu))
+                CPU_SET(iCpu, &LnxCpuSet);
+
+    int rc = pthread_setaffinity_np(pthread_self(), sizeof(LnxCpuSet), &LnxCpuSet);
+    if (!rc)
+        return VINF_SUCCESS;
+    rc = errno;
+    if (rc == ENOENT)
+        return VERR_CPU_NOT_FOUND;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTThreadGetAffinity(PRTCPUSET pCpuSet)
+{
+    cpu_set_t LnxCpuSet;
+    int rc = pthread_getaffinity_np(pthread_self(), sizeof(LnxCpuSet), &LnxCpuSet);
+    if (rc != 0)
+        return RTErrConvertFromErrno(errno);
+
+    /* convert */
+    RTCpuSetEmpty(pCpuSet);
+    for (unsigned iCpu = 0; iCpu < RT_MIN(CPU_SETSIZE, RTCPUSET_MAX_CPUS); iCpu++)
+        if (CPU_ISSET(iCpu, &LnxCpuSet))
+            RTCpuSetAddByIndex(pCpuSet, iCpu);
+
+    return VINF_SUCCESS;
+}
+
+#else
+# include "../../generic/RTThreadGetAffinity-stub-generic.cpp"
+# include "../../generic/RTThreadSetAffinity-stub-generic.cpp"
+#endif
+
diff --git a/src/VBox/Runtime/r3/linux/time-linux.cpp b/src/VBox/Runtime/r3/linux/time-linux.cpp
new file mode 100644
index 00000000..6ceac2de
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/time-linux.cpp
@@ -0,0 +1,169 @@
+/* $Id: time-linux.cpp $ */
+/** @file
+ * IPRT - Time, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <sys/time.h>
+#include <time.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#ifndef __NR_clock_gettime
+# define __NR_timer_create      259
+# define __NR_clock_gettime     (__NR_timer_create+6)
+#endif
+
+#include <iprt/time.h>
+#include "internal/time.h"
+
+
+DECLINLINE(int) sys_clock_gettime(clockid_t id,  struct timespec *ts)
+{
+    int rc = syscall(__NR_clock_gettime, id, ts);
+    if (rc >= 0)
+        return rc;
+    return -1;
+}
+
+
+/**
+ * Wrapper around various monotone time sources.
+ */
+DECLINLINE(int) mono_clock(struct timespec *ts)
+{
+    static int iWorking = -1;
+    switch (iWorking)
+    {
+#ifdef CLOCK_MONOTONIC
+        /*
+         * Standard clock_gettime()
+         */
+        case 0:
+            return clock_gettime(CLOCK_MONOTONIC, ts);
+
+        /*
+         * Syscall clock_gettime().
+         */
+        case 1:
+            return sys_clock_gettime(CLOCK_MONOTONIC, ts);
+
+#endif /* CLOCK_MONOTONIC */
+
+
+        /*
+         * Figure out what's working.
+         */
+        case -1:
+        {
+#ifdef CLOCK_MONOTONIC
+            /*
+             * Real-Time API.
+             */
+            int rc = clock_gettime(CLOCK_MONOTONIC, ts);
+            if (!rc)
+            {
+                iWorking = 0;
+                return 0;
+            }
+
+            rc = sys_clock_gettime(CLOCK_MONOTONIC, ts);
+            if (!rc)
+            {
+                iWorking = 1;
+                return 0;
+            }
+#endif /* CLOCK_MONOTONIC */
+
+            /* give up */
+            iWorking = -2;
+            break;
+        }
+    }
+    return -1;
+}
+
+
+DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
+{
+    /* check monotonic clock first. */
+    static bool fMonoClock = true;
+    if (fMonoClock)
+    {
+        struct timespec ts;
+        if (!mono_clock(&ts))
+            return (uint64_t)ts.tv_sec * RT_NS_1SEC_64
+                 + ts.tv_nsec;
+        fMonoClock = false;
+    }
+
+    /* fallback to gettimeofday(). */
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return (uint64_t)tv.tv_sec  * RT_NS_1SEC_64
+         + (uint64_t)(tv.tv_usec * RT_NS_1US);
+}
+
+
+/**
+ * Gets the current nanosecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns nanosecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+/**
+ * Gets the current millisecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns millisecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
diff --git a/src/VBox/Runtime/r3/linux/tpm-linux.cpp b/src/VBox/Runtime/r3/linux/tpm-linux.cpp
new file mode 100644
index 00000000..4851eabc
--- /dev/null
+++ b/src/VBox/Runtime/r3/linux/tpm-linux.cpp
@@ -0,0 +1,229 @@
+/* $Id: tpm-linux.cpp $ */
+/** @file
+ * IPRT - Trusted Platform Module (TPM) access, Linux variant.
+ */
+
+/*
+ * Copyright (C) 2021-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/tpm.h>
+
+#include <iprt/assertcompile.h>
+#include <iprt/asm.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/linux/sysfs.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Internal TPM instance data.
+ */
+typedef struct RTTPMINT
+{
+    /** Handle to the /dev/tpmX device. */
+    RTFILE                      hTpmDev;
+    /** Handle to the sysfs cancel interface. */
+    RTFILE                      hTpmCancel;
+    /** The deduced TPM version. */
+    RTTPMVERSION                enmTpmVers;
+    /** Flag whether a request is currently being executed. */
+    volatile bool               fReqExec;
+} RTTPMINT;
+/** Pointer to the internal TPM instance data. */
+typedef RTTPMINT *PRTTPMINT;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+RTDECL(int) RTTpmOpen(PRTTPM phTpm, uint32_t idTpm)
+{
+    AssertPtrReturn(phTpm, VERR_INVALID_POINTER);
+    if (idTpm == RTTPM_ID_DEFAULT)
+        idTpm = 0;
+
+    int rc = VINF_SUCCESS;
+    PRTTPMINT pThis = (PRTTPMINT)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        pThis->hTpmDev    = NIL_RTFILE;
+        pThis->hTpmCancel = NIL_RTFILE;
+        pThis->enmTpmVers = RTTPMVERSION_UNKNOWN;
+        pThis->fReqExec   = false;
+
+        rc = RTFileOpenF(&pThis->hTpmDev, RTFILE_O_OPEN | RTFILE_O_READWRITE | RTFILE_O_DENY_NONE,
+                         "/dev/tpm%u", idTpm);
+        if (RT_SUCCESS(rc))
+        {
+            /* Open the sysfs path to cancel a request, either /sys/class/tpm/tpmX/device/cancel or /sys/class/misc/tpmX/device/cancel. */
+            rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
+                             "/sys/class/tpm/tpm%u/device/cancel", idTpm);
+            if (rc == VERR_FILE_NOT_FOUND)
+                rc = RTFileOpenF(&pThis->hTpmCancel, RTFILE_O_OPEN | RTFILE_O_WRITE | RTFILE_O_DENY_NONE,
+                                 "/sys/class/misc/tpm%u/device/cancel", idTpm);
+            if (   RT_SUCCESS(rc)
+                || rc == VERR_FILE_NOT_FOUND)
+            {
+                /* Try to figure out the TPM version. */
+                int64_t iVersion = 0;
+                rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/tpm/tpm%u/tpm_version_major", idTpm);
+                if (rc == VERR_FILE_NOT_FOUND)
+                    rc = RTLinuxSysFsReadIntFile(10 /*uBase*/, &iVersion, "/sys/class/misc/tpm%u/tpm_version_major", idTpm);
+                if (RT_SUCCESS(rc))
+                {
+                    if (iVersion == 1)
+                        pThis->enmTpmVers = RTTPMVERSION_1_2;
+                    else if (iVersion == 2)
+                        pThis->enmTpmVers = RTTPMVERSION_2_0;
+                }
+
+                *phTpm = pThis;
+                return VINF_SUCCESS;
+            }
+
+            RTFileClose(pThis->hTpmDev);
+            pThis->hTpmDev = NIL_RTFILE;
+        }
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+    return rc;
+}
+
+
+RTDECL(int) RTTpmClose(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+
+    RTFileClose(pThis->hTpmDev);
+    if (pThis->hTpmCancel != NIL_RTFILE)
+        RTFileClose(pThis->hTpmCancel);
+
+    pThis->hTpmDev    = NIL_RTFILE;
+    pThis->hTpmCancel = NIL_RTFILE;
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTTPMVERSION) RTTpmGetVersion(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, RTTPMVERSION_INVALID);
+    return pThis->enmTpmVers;
+}
+
+
+RTDECL(uint32_t) RTTpmGetLocalityMax(RTTPM hTpm)
+{
+    RT_NOREF(hTpm);
+    return 0; /* On Linux only TPM locality 0 is supported. */
+}
+
+
+RTDECL(int) RTTpmReqCancel(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    if (pThis->hTpmCancel == NIL_RTFILE)
+        return VERR_NOT_SUPPORTED;
+
+    if (ASMAtomicReadBool(&pThis->fReqExec))
+    {
+        uint8_t bCancel = '-';
+        return RTFileWrite(pThis->hTpmCancel, &bCancel, sizeof(bCancel), NULL /*pcbWritten*/);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTTpmReqExec(RTTPM hTpm, uint8_t bLoc, const void *pvReq, size_t cbReq,
+                         void *pvResp, size_t cbRespMax, size_t *pcbResp)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvReq, VERR_INVALID_POINTER);
+    AssertPtrReturn(pvResp, VERR_INVALID_POINTER);
+    AssertReturn(cbReq && cbRespMax, VERR_INVALID_PARAMETER);
+    AssertReturn(bLoc == 0, VERR_NOT_SUPPORTED); /** @todo There doesn't seem to be a way to use a different locality. */
+
+    /* The request has to be supplied by a single blocking write. */
+    ASMAtomicXchgBool(&pThis->fReqExec, true);
+    int rc = RTFileWrite(pThis->hTpmDev, pvReq, cbReq, NULL /*pcbWritten*/);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbResp = 0;
+        /* The response has to be retrieved in a single read as well. */
+        rc = RTFileRead(pThis->hTpmDev, pvResp, cbRespMax, &cbResp);
+        ASMAtomicXchgBool(&pThis->fReqExec, false);
+        if (RT_SUCCESS(rc))
+        {
+            /* Check whether the response is complete. */
+            if (   cbResp >= sizeof(TPMRESPHDR)
+                && RTTpmRespGetSz((PCTPMRESPHDR)pvResp) == cbResp)
+            {
+                if (pcbResp)
+                    *pcbResp = cbResp;
+            }
+            else
+                rc = VERR_BUFFER_OVERFLOW;
+        }
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/memsafer-r3.cpp b/src/VBox/Runtime/r3/memsafer-r3.cpp
new file mode 100644
index 00000000..bafeed96
--- /dev/null
+++ b/src/VBox/Runtime/r3/memsafer-r3.cpp
@@ -0,0 +1,691 @@
+/* $Id: memsafer-r3.cpp $ */
+/** @file
+ * IPRT - Memory Allocate for Sensitive Data, generic heap-based implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/memsafer.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/avl.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/rand.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#ifdef IN_SUP_R3
+# include <VBox/sup.h>
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Allocation size alignment (power of two). */
+#define RTMEMSAFER_ALIGN        16
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Allocators.
+ */
+typedef enum RTMEMSAFERALLOCATOR
+{
+    /** Invalid method. */
+    RTMEMSAFERALLOCATOR_INVALID = 0,
+    /** RTMemPageAlloc. */
+    RTMEMSAFERALLOCATOR_RTMEMPAGE,
+    /** SUPR3PageAllocEx. */
+    RTMEMSAFERALLOCATOR_SUPR3
+} RTMEMSAFERALLOCATOR;
+
+/**
+ * Tracking node (lives on normal heap).
+ */
+typedef struct RTMEMSAFERNODE
+{
+    /** Node core.
+     * The core key is a scrambled pointer the user memory. */
+    AVLPVNODECORE           Core;
+    /** The allocation flags. */
+    uint32_t                fFlags;
+    /** The offset into the allocation of the user memory. */
+    uint32_t                offUser;
+    /** The requested allocation size. */
+    size_t                  cbUser;
+    /** The allocation size in pages, this includes the two guard pages. */
+    uint32_t                cPages;
+    /** The allocator used for this node. */
+    RTMEMSAFERALLOCATOR     enmAllocator;
+    /** XOR scrambler value for memory. */
+    uintptr_t               uScramblerXor;
+} RTMEMSAFERNODE;
+/** Pointer to an allocation tracking node. */
+typedef RTMEMSAFERNODE *PRTMEMSAFERNODE;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Init once structure for this module. */
+static RTONCE       g_MemSaferOnce = RTONCE_INITIALIZER;
+/** Critical section protecting the allocation tree. */
+static RTCRITSECTRW g_MemSaferCritSect;
+/** Tree of allocation nodes. */
+static AVLPVTREE    g_pMemSaferTree;
+/** XOR scrambler value pointers. */
+static uintptr_t    g_uMemSaferPtrScramblerXor;
+/** Pointer rotate shift count.*/
+static uintptr_t    g_cMemSaferPtrScramblerRotate;
+
+
+/**
+ * @callback_method_impl{FNRTONCE, Inits globals.}
+ */
+static DECLCALLBACK(int32_t) rtMemSaferOnceInit(void *pvUserIgnore)
+{
+    RT_NOREF_PV(pvUserIgnore);
+
+    g_uMemSaferPtrScramblerXor = (uintptr_t)RTRandU64();
+    g_cMemSaferPtrScramblerRotate = RTRandU32Ex(0, ARCH_BITS - 1);
+    return RTCritSectRwInit(&g_MemSaferCritSect);
+}
+
+
+/**
+ * @callback_method_impl{PFNRTONCECLEANUP, Cleans up globals.}
+ */
+static DECLCALLBACK(void) rtMemSaferOnceTerm(void *pvUser, bool fLazyCleanUpOk)
+{
+    RT_NOREF_PV(pvUser);
+
+    if (!fLazyCleanUpOk)
+    {
+        RTCritSectRwDelete(&g_MemSaferCritSect);
+        Assert(!g_pMemSaferTree);
+    }
+}
+
+
+
+DECLINLINE(void *) rtMemSaferScramblePointer(void *pvUser)
+{
+    uintptr_t uPtr = (uintptr_t)pvUser;
+    uPtr ^= g_uMemSaferPtrScramblerXor;
+#if ARCH_BITS == 64
+    uPtr = ASMRotateRightU64(uPtr, g_cMemSaferPtrScramblerRotate);
+#elif ARCH_BITS == 32
+    uPtr = ASMRotateRightU32(uPtr, g_cMemSaferPtrScramblerRotate);
+#else
+# error "Unsupported/missing ARCH_BITS."
+#endif
+    return (void *)uPtr;
+}
+
+
+/**
+ * Inserts a tracking node into the tree.
+ *
+ * @param   pThis               The allocation tracking node to insert.
+ */
+static void rtMemSaferNodeInsert(PRTMEMSAFERNODE pThis)
+{
+    RTCritSectRwEnterExcl(&g_MemSaferCritSect);
+    pThis->Core.Key = rtMemSaferScramblePointer(pThis->Core.Key);
+    bool fRc = RTAvlPVInsert(&g_pMemSaferTree, &pThis->Core);
+    RTCritSectRwLeaveExcl(&g_MemSaferCritSect);
+    Assert(fRc); NOREF(fRc);
+}
+
+
+/**
+ * Finds a tracking node into the tree.
+ *
+ * @returns The allocation tracking node for @a pvUser. NULL if not found.
+ * @param   pvUser              The user pointer to the allocation.
+ */
+static PRTMEMSAFERNODE rtMemSaferNodeLookup(void *pvUser)
+{
+    void *pvKey = rtMemSaferScramblePointer(pvUser);
+    RTCritSectRwEnterShared(&g_MemSaferCritSect);
+    PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVGet(&g_pMemSaferTree, pvKey);
+    RTCritSectRwLeaveShared(&g_MemSaferCritSect);
+    return pThis;
+}
+
+
+/**
+ * Removes a tracking node from the tree.
+ *
+ * @returns The allocation tracking node for @a pvUser. NULL if not found.
+ * @param   pvUser              The user pointer to the allocation.
+ */
+static PRTMEMSAFERNODE rtMemSaferNodeRemove(void *pvUser)
+{
+    void *pvKey = rtMemSaferScramblePointer(pvUser);
+    RTCritSectRwEnterExcl(&g_MemSaferCritSect);
+    PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVRemove(&g_pMemSaferTree, pvKey);
+    RTCritSectRwLeaveExcl(&g_MemSaferCritSect);
+    return pThis;
+}
+
+
+RTDECL(int) RTMemSaferScramble(void *pv, size_t cb)
+{
+    PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
+    AssertReturn(pThis, VERR_INVALID_POINTER);
+    AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
+
+    /* First time we get a new xor value. */
+    if (!pThis->uScramblerXor)
+        pThis->uScramblerXor = (uintptr_t)RTRandU64();
+
+    /* Note! This isn't supposed to be safe, just less obvious. */
+    uintptr_t *pu = (uintptr_t *)pv;
+    cb = RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN);
+    while (cb > 0)
+    {
+        *pu ^= pThis->uScramblerXor;
+        pu++;
+        cb -= sizeof(*pu);
+    }
+
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTMemSaferScramble);
+
+
+RTDECL(int) RTMemSaferUnscramble(void *pv, size_t cb)
+{
+    PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pv);
+    AssertReturn(pThis, VERR_INVALID_POINTER);
+    AssertMsgReturn(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser), VERR_INVALID_PARAMETER);
+
+    /* Note! This isn't supposed to be safe, just less obvious. */
+    uintptr_t *pu = (uintptr_t *)pv;
+    cb = RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN);
+    while (cb > 0)
+    {
+        *pu ^= pThis->uScramblerXor;
+        pu++;
+        cb -= sizeof(*pu);
+    }
+
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTMemSaferUnscramble);
+
+
+/**
+ * Initializes the pages.
+ *
+ * Fills the memory with random bytes in order to make it less obvious where the
+ * secret data starts and ends.  We also zero the user memory in case the
+ * allocator does not do this.
+ *
+ * @param   pThis               The allocation tracer node.  The Core.Key member
+ *                              will be set.
+ * @param   pvPages             The pages to initialize.
+ */
+static void rtMemSaferInitializePages(PRTMEMSAFERNODE pThis, void *pvPages)
+{
+    RTRandBytes(pvPages, PAGE_SIZE + pThis->offUser);
+
+    uint8_t *pbUser = (uint8_t *)pvPages + PAGE_SIZE + pThis->offUser;
+    pThis->Core.Key = pbUser;
+    RT_BZERO(pbUser, pThis->cbUser); /* paranoia */
+
+    RTRandBytes(pbUser + pThis->cbUser, (size_t)pThis->cPages * PAGE_SIZE - PAGE_SIZE - pThis->offUser - pThis->cbUser);
+}
+
+
+/**
+ * Allocates and initializes pages from the support driver and initializes it.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The allocator node. Core.Key will be set on successful
+ *                      return (unscrambled).
+ */
+static int rtMemSaferSupR3AllocPages(PRTMEMSAFERNODE pThis)
+{
+#ifdef IN_SUP_R3
+    /*
+     * Try allocate the memory.
+     */
+    void *pvPages;
+    int rc = SUPR3PageAllocEx(pThis->cPages, 0 /* fFlags */, &pvPages, NULL /* pR0Ptr */, NULL /* paPages */);
+    if (RT_SUCCESS(rc))
+    {
+        rtMemSaferInitializePages(pThis, pvPages);
+
+        /*
+         * On darwin we cannot allocate pages without an R0 mapping and
+         * SUPR3PageAllocEx falls back to another method which is incompatible with
+         * the way SUPR3PageProtect works. Ignore changing the protection of the guard
+         * pages.
+         */
+#ifdef RT_OS_DARWIN
+        return VINF_SUCCESS;
+#else
+        /*
+         * Configure the guard pages.
+         * SUPR3PageProtect isn't supported on all hosts, we ignore that.
+         */
+        rc = SUPR3PageProtect(pvPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_NONE);
+        if (RT_SUCCESS(rc))
+        {
+            rc = SUPR3PageProtect(pvPages, NIL_RTR0PTR, (pThis->cPages - 1) * PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_NONE);
+            if (RT_SUCCESS(rc))
+                return VINF_SUCCESS;
+            SUPR3PageProtect(pvPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+        }
+        else if (rc == VERR_NOT_SUPPORTED)
+            return VINF_SUCCESS;
+
+        /* failed. */
+        int rc2 = SUPR3PageFreeEx(pvPages, pThis->cPages); AssertRC(rc2);
+#endif
+    }
+    return rc;
+
+#else  /* !IN_SUP_R3 */
+    RT_NOREF_PV(pThis);
+    return VERR_NOT_SUPPORTED;
+#endif /* !IN_SUP_R3 */
+}
+
+
+/**
+ * Allocates and initializes pages using the IPRT page allocator API.
+ *
+ * @returns VBox status code.
+ * @param   pThis       The allocator node. Core.Key will be set on successful
+ *                      return (unscrambled).
+ */
+static int rtMemSaferMemAllocPages(PRTMEMSAFERNODE pThis)
+{
+    /*
+     * Try allocate the memory.
+     */
+    int rc = VINF_SUCCESS;
+    void *pvPages = RTMemPageAllocEx((size_t)pThis->cPages * PAGE_SIZE,
+                                     RTMEMPAGEALLOC_F_ADVISE_LOCKED | RTMEMPAGEALLOC_F_ADVISE_NO_DUMP | RTMEMPAGEALLOC_F_ZERO);
+    if (pvPages)
+    {
+        rtMemSaferInitializePages(pThis, pvPages);
+
+        /*
+         * Configure the guard pages.
+         */
+        rc = RTMemProtect(pvPages, PAGE_SIZE, RTMEM_PROT_NONE);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTMemProtect((uint8_t *)pvPages + (size_t)(pThis->cPages - 1U) * PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_NONE);
+            if (RT_SUCCESS(rc))
+                return VINF_SUCCESS;
+            rc = RTMemProtect(pvPages, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+        }
+
+        /* failed. */
+        RTMemPageFree(pvPages, (size_t)pThis->cPages * PAGE_SIZE);
+    }
+    else
+        rc = VERR_NO_PAGE_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTMemSaferAllocZExTag(void **ppvNew, size_t cb, uint32_t fFlags, const char *pszTag) RT_NO_THROW_DEF
+{
+    RT_NOREF_PV(pszTag);
+
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(ppvNew, VERR_INVALID_PARAMETER);
+    *ppvNew = NULL;
+    AssertReturn(cb, VERR_INVALID_PARAMETER);
+    AssertReturn(cb <= 32U*_1M - PAGE_SIZE * 3U, VERR_ALLOCATION_TOO_BIG); /* Max 32 MB minus padding and guard pages. */
+    AssertReturn(!(fFlags & ~RTMEMSAFER_F_VALID_MASK), VERR_INVALID_FLAGS);
+
+    /*
+     * Initialize globals.
+     */
+    int rc = RTOnceEx(&g_MemSaferOnce, rtMemSaferOnceInit, rtMemSaferOnceTerm, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Allocate a tracker node first.
+         */
+        PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTMemAllocZ(sizeof(RTMEMSAFERNODE));
+        if (pThis)
+        {
+            /*
+             * Prepare the allocation.
+             */
+            pThis->cbUser  = cb;
+            pThis->offUser = (RTRandU32Ex(0, 128) * RTMEMSAFER_ALIGN) & PAGE_OFFSET_MASK;
+
+            size_t cbNeeded = pThis->offUser + pThis->cbUser;
+            cbNeeded = RT_ALIGN_Z(cbNeeded, PAGE_SIZE);
+
+            pThis->cPages = (uint32_t)(cbNeeded / PAGE_SIZE) + 2; /* +2 for guard pages */
+
+            /*
+             * Try allocate the memory, using the best allocator by default and
+             * falling back on the less safe one.
+             */
+            rc = rtMemSaferSupR3AllocPages(pThis);
+            if (RT_SUCCESS(rc))
+                pThis->enmAllocator = RTMEMSAFERALLOCATOR_SUPR3;
+            else if (!(fFlags & RTMEMSAFER_F_REQUIRE_NOT_PAGABLE))
+            {
+                rc = rtMemSaferMemAllocPages(pThis);
+                if (RT_SUCCESS(rc))
+                    pThis->enmAllocator = RTMEMSAFERALLOCATOR_RTMEMPAGE;
+            }
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Insert the node.
+                 */
+                *ppvNew = pThis->Core.Key;
+                rtMemSaferNodeInsert(pThis); /* (Scrambles Core.Key) */
+                return VINF_SUCCESS;
+            }
+
+            RTMemFree(pThis);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTMemSaferAllocZExTag);
+
+
+RTDECL(void) RTMemSaferFree(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    if (pv)
+    {
+        PRTMEMSAFERNODE pThis = rtMemSaferNodeRemove(pv);
+        AssertReturnVoid(pThis);
+        if (cb == 0) /* for openssl use */
+            cb = pThis->cbUser;
+        else
+            AssertMsg(cb == pThis->cbUser, ("cb=%#zx != %#zx\n", cb, pThis->cbUser));
+
+        /*
+         * Wipe the user memory first.
+         */
+        RTMemWipeThoroughly(pv, RT_ALIGN_Z(cb, RTMEMSAFER_ALIGN), 3);
+
+        /*
+         * Free the pages.
+         */
+        uint8_t *pbPages = (uint8_t *)pv - pThis->offUser - PAGE_SIZE;
+        size_t   cbPages = (size_t)pThis->cPages * PAGE_SIZE;
+        switch (pThis->enmAllocator)
+        {
+#ifdef IN_SUP_R3
+            case RTMEMSAFERALLOCATOR_SUPR3:
+                SUPR3PageProtect(pbPages, NIL_RTR0PTR, 0, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+                SUPR3PageProtect(pbPages, NIL_RTR0PTR, (uint32_t)(cbPages - PAGE_SIZE), PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+                SUPR3PageFreeEx(pbPages, pThis->cPages);
+                break;
+#endif
+            case RTMEMSAFERALLOCATOR_RTMEMPAGE:
+                RTMemProtect(pbPages, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+                RTMemProtect(pbPages + cbPages - PAGE_SIZE, PAGE_SIZE, RTMEM_PROT_READ | RTMEM_PROT_WRITE);
+                RTMemPageFree(pbPages, cbPages);
+                break;
+
+            default:
+                AssertFailed();
+        }
+
+        /*
+         * Free the tracking node.
+         */
+        pThis->Core.Key = NULL;
+        pThis->offUser = 0;
+        pThis->cbUser = 0;
+        RTMemFree(pThis);
+    }
+    else
+        Assert(cb == 0);
+}
+RT_EXPORT_SYMBOL(RTMemSaferFree);
+
+
+RTDECL(size_t) RTMemSaferGetSize(void *pv) RT_NO_THROW_DEF
+{
+    size_t cbRet = 0;
+    if (pv)
+    {
+        /*
+         * We use this API for testing whether pv is a safer allocation or not,
+         * so we may be called before the allocators.  Thus, it's prudent to
+         * make sure initialization has taken place before attempting to enter
+         * the critical section and such.
+         */
+        int rc = RTOnceEx(&g_MemSaferOnce, rtMemSaferOnceInit, rtMemSaferOnceTerm, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            void *pvKey = rtMemSaferScramblePointer(pv);
+            RTCritSectRwEnterShared(&g_MemSaferCritSect);
+            PRTMEMSAFERNODE pThis = (PRTMEMSAFERNODE)RTAvlPVGet(&g_pMemSaferTree, pvKey);
+            if (pThis)
+                cbRet = pThis->cbUser;
+            RTCritSectRwLeaveShared(&g_MemSaferCritSect);
+        }
+    }
+    return cbRet;
+}
+RT_EXPORT_SYMBOL(RTMemSaferGetSize);
+
+
+/**
+ * The simplest reallocation method: allocate new block, copy over the data,
+ * free old block.
+ */
+static int rtMemSaferReallocSimpler(size_t cbOld, void *pvOld, size_t cbNew, void **ppvNew, uint32_t fFlags, const char *pszTag)
+{
+    void *pvNew;
+    int rc = RTMemSaferAllocZExTag(&pvNew, cbNew, fFlags, pszTag);
+    if (RT_SUCCESS(rc))
+    {
+        memcpy(pvNew, pvOld, RT_MIN(cbNew, cbOld));
+        RTMemSaferFree(pvOld, cbOld);
+        *ppvNew = pvNew;
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTMemSaferReallocZExTag(size_t cbOld, void *pvOld, size_t cbNew, void **ppvNew, uint32_t fFlags, const char *pszTag) RT_NO_THROW_DEF
+{
+    int rc;
+    /* Real realloc. */
+    if (cbNew && cbOld)
+    {
+        PRTMEMSAFERNODE pThis = rtMemSaferNodeLookup(pvOld);
+        AssertReturn(pThis, VERR_INVALID_POINTER);
+        AssertMsgStmt(cbOld == pThis->cbUser, ("cbOld=%#zx != %#zx\n", cbOld, pThis->cbUser), cbOld = pThis->cbUser);
+
+        if (pThis->fFlags == fFlags)
+        {
+            if (cbNew > cbOld)
+            {
+                /*
+                 * Is the enough room for us to grow?
+                 */
+                size_t cbMax = (size_t)(pThis->cPages - 2) * PAGE_SIZE;
+                if (cbNew <= cbMax)
+                {
+                    size_t const cbAdded = (cbNew - cbOld);
+                    size_t const cbAfter = cbMax - pThis->offUser - cbOld;
+                    if (cbAfter >= cbAdded)
+                    {
+                        /*
+                         * Sufficient space after the current allocation.
+                         */
+                        uint8_t *pbNewSpace = (uint8_t *)pvOld + cbOld;
+                        RT_BZERO(pbNewSpace, cbAdded);
+                        *ppvNew = pvOld;
+                    }
+                    else
+                    {
+                        /*
+                         * Have to move the allocation to make enough room at the
+                         * end.  In order to make it a little less predictable and
+                         * maybe avoid a relocation or two in the next call, divide
+                         * the page offset by four until it it fits.
+                         */
+                        AssertReturn(rtMemSaferNodeRemove(pvOld) == pThis, VERR_INTERNAL_ERROR_3);
+                        uint32_t offNewUser = pThis->offUser;
+                        do
+                            offNewUser = offNewUser / 2;
+                        while ((pThis->offUser - offNewUser) + cbAfter < cbAdded);
+                        offNewUser &= ~(RTMEMSAFER_ALIGN - 1U);
+
+                        uint32_t const cbMove = pThis->offUser - offNewUser;
+                        uint8_t *pbNew = (uint8_t *)pvOld - cbMove;
+                        memmove(pbNew, pvOld, cbOld);
+
+                        RT_BZERO(pbNew + cbOld, cbAdded);
+                        if (cbMove > cbAdded)
+                            RTMemWipeThoroughly(pbNew + cbNew, cbMove - cbAdded, 3);
+
+                        pThis->offUser  = offNewUser;
+                        pThis->Core.Key = pbNew;
+                        *ppvNew = pbNew;
+
+                        rtMemSaferNodeInsert(pThis);
+                    }
+                    Assert(((uintptr_t)*ppvNew & PAGE_OFFSET_MASK) == pThis->offUser);
+                    pThis->cbUser = cbNew;
+                    rc = VINF_SUCCESS;
+                }
+                else
+                {
+                    /*
+                     * Not enough space, allocate a new block and copy over the data.
+                     */
+                    rc = rtMemSaferReallocSimpler(cbOld, pvOld, cbNew, ppvNew, fFlags, pszTag);
+                }
+            }
+            else
+            {
+                /*
+                 * Shrinking the allocation, just wipe the memory that is no longer
+                 * being used.
+                 */
+                if (cbNew != cbOld)
+                {
+                    uint8_t *pbAbandond = (uint8_t *)pvOld + cbNew;
+                    RTMemWipeThoroughly(pbAbandond, cbOld - cbNew, 3);
+                }
+                pThis->cbUser = cbNew;
+                *ppvNew = pvOld;
+                rc = VINF_SUCCESS;
+            }
+        }
+        else if (!pThis->fFlags)
+        {
+            /*
+             * New flags added. Allocate a new block and copy over the old one.
+             */
+            rc = rtMemSaferReallocSimpler(cbOld, pvOld, cbNew, ppvNew, fFlags, pszTag);
+        }
+        else
+        {
+            /* Compatible flags. */
+            AssertMsgFailed(("fFlags=%#x old=%#x\n", fFlags, pThis->fFlags));
+            rc = VERR_INVALID_FLAGS;
+        }
+    }
+    /*
+     * First allocation. Pass it on.
+     */
+    else if (!cbOld)
+    {
+        Assert(pvOld == NULL);
+        rc = RTMemSaferAllocZExTag(ppvNew, cbNew, fFlags, pszTag);
+    }
+    /*
+     * Free operation. Pass it on.
+     */
+    else
+    {
+        RTMemSaferFree(pvOld, cbOld);
+        *ppvNew = NULL;
+        rc = VINF_SUCCESS;
+    }
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTMemSaferReallocZExTag);
+
+
+RTDECL(void *) RTMemSaferAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    void *pvNew = NULL;
+    int rc = RTMemSaferAllocZExTag(&pvNew, cb, 0 /*fFlags*/, pszTag);
+    if (RT_SUCCESS(rc))
+        return pvNew;
+    return NULL;
+}
+RT_EXPORT_SYMBOL(RTMemSaferAllocZTag);
+
+
+RTDECL(void *) RTMemSaferReallocZTag(size_t cbOld, void *pvOld, size_t cbNew, const char *pszTag) RT_NO_THROW_DEF
+{
+    void *pvNew = NULL;
+    int rc = RTMemSaferReallocZExTag(cbOld, pvOld, cbNew, &pvNew, 0 /*fFlags*/, pszTag);
+    if (RT_SUCCESS(rc))
+        return pvNew;
+    return NULL;
+}
+RT_EXPORT_SYMBOL(RTMemSaferReallocZTag);
+
diff --git a/src/VBox/Runtime/r3/netbsd/Makefile.kup b/src/VBox/Runtime/r3/netbsd/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/netbsd/Makefile.kup
diff --git a/src/VBox/Runtime/r3/netbsd/rtProcInitExePath-netbsd.cpp b/src/VBox/Runtime/r3/netbsd/rtProcInitExePath-netbsd.cpp
new file mode 100644
index 00000000..90566b7a
--- /dev/null
+++ b/src/VBox/Runtime/r3/netbsd/rtProcInitExePath-netbsd.cpp
@@ -0,0 +1,110 @@
+/* $Id: rtProcInitExePath-netbsd.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, NetBSD.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <dlfcn.h>
+#include <link.h>
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Read the /proc/curproc/file link, convert to native and return it.
+     */
+    int cchLink = readlink("/proc/curproc/exe", pszPath, cchPath - 1);
+    if (cchLink > 0 && (size_t)cchLink <= cchPath - 1)
+    {
+        pszPath[cchLink] = '\0';
+
+        char const *pszTmp;
+        int rc = rtPathFromNative(&pszTmp, pszPath, NULL);
+        AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchLink, pszPath), rc);
+        if (pszTmp != pszPath)
+        {
+            rc = RTStrCopy(pszPath, cchPath, pszTmp);
+            rtPathFreeIprt(pszTmp, pszPath);
+        }
+        return rc;
+    }
+
+    int err = errno;
+
+    /*
+     * Fall back on the dynamic linker since /proc is optional.
+     */
+    void *hExe = dlopen(NULL, 0);
+    if (hExe)
+    {
+        struct link_map const *pLinkMap = 0;
+        if (dlinfo(hExe, RTLD_DI_LINKMAP, &pLinkMap) == 0)
+        {
+            const char *pszImageName = pLinkMap->l_name;
+            if (*pszImageName == '/') /* this may not always be absolute, despite the docs. :-( */
+            {
+                char const *pszTmp;
+                int rc = rtPathFromNative(&pszTmp, pszImageName, NULL);
+                AssertMsgRCReturn(rc, ("rc=%Rrc pszImageName=\"%s\"\n", rc, pszImageName), rc);
+                if (pszTmp != pszPath)
+                {
+                    rc = RTStrCopy(pszPath, cchPath, pszTmp);
+                    rtPathFreeIprt(pszTmp, pszPath);
+                }
+                return rc;
+            }
+            /** @todo Try search the PATH for the file name or append the current
+             *        directory, which ever makes sense... */
+        }
+    }
+
+    int rc = RTErrConvertFromErrno(err);
+    AssertMsgFailed(("rc=%Rrc err=%d cchLink=%d hExe=%p\n", rc, err, cchLink, hExe));
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/nocrt-cerr.cpp b/src/VBox/Runtime/r3/nocrt-cerr.cpp
new file mode 100644
index 00000000..71c294f8
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-cerr.cpp
@@ -0,0 +1,52 @@
+/* $Id: nocrt-cerr.cpp $ */
+/** @file
+ * IPRT - No-CRT - std::cerr.
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+#include <iprt/nocrt/iostream>
+#include <iprt/nocrt/fstream>
+#include <iprt/stream.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+std::basic_filebuf<char, std::char_traits<char> > g_rtNoCrtCerrBuf(g_pStdErr, true /*a_fStdStream*/);
+std::ostream std::cerr(&g_rtNoCrtCerrBuf, &std::cout /*a_pTiedStream*/, true /*a_fUnbuffered*/);
+
diff --git a/src/VBox/Runtime/r3/nocrt-clearerr.cpp b/src/VBox/Runtime/r3/nocrt-clearerr.cpp
new file mode 100644
index 00000000..ecd3ce69
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-clearerr.cpp
@@ -0,0 +1,53 @@
+/* $Id: nocrt-clearerr.cpp $ */
+/** @file
+ * IPRT - No-CRT - clearerr().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/stream.h>
+
+
+#undef clearerr
+void RT_NOCRT(clearerr)(FILE *pFile)
+{
+    RTStrmClearError(pFile);
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(clearerr);
+
diff --git a/src/VBox/Runtime/r3/nocrt-cout.cpp b/src/VBox/Runtime/r3/nocrt-cout.cpp
new file mode 100644
index 00000000..5323359f
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-cout.cpp
@@ -0,0 +1,52 @@
+/* $Id: nocrt-cout.cpp $ */
+/** @file
+ * IPRT - No-CRT - std::cout.
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+#include <iprt/nocrt/iostream>
+#include <iprt/nocrt/fstream>
+#include <iprt/stream.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+std::basic_filebuf<char, std::char_traits<char> > g_rtNoCrtCoutBuf(g_pStdOut, true /*a_fStdStream*/);
+std::ostream std::cout(&g_rtNoCrtCoutBuf, NULL /*a_pTiedStream*/, false /*a_fUnbuffered*/);
+
diff --git a/src/VBox/Runtime/r3/nocrt-errno.cpp b/src/VBox/Runtime/r3/nocrt-errno.cpp
new file mode 100644
index 00000000..7a931a0f
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-errno.cpp
@@ -0,0 +1,55 @@
+/* $Id: nocrt-errno.cpp $ */
+/** @file
+ * IPRT - No-CRT - Per-thread errno variable.
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/errno.h>
+
+
+RTDECL(int *) rtNoCrtGetErrnoPtr(void)
+{
+    PRTNOCRTTHREADDATA pNoCrtData = rtNoCrtThreadDataGet();
+    if (pNoCrtData)
+        return &pNoCrtData->iErrno;
+
+    static int s_iFallbackErrno;
+    return &s_iFallbackErrno;
+}
+
diff --git a/src/VBox/Runtime/r3/nocrt-fclose.cpp b/src/VBox/Runtime/r3/nocrt-fclose.cpp
new file mode 100644
index 00000000..8cd90a79
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fclose.cpp
@@ -0,0 +1,59 @@
+/* $Id: nocrt-fclose.cpp $ */
+/** @file
+ * IPRT - No-CRT - fclose().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fclose
+int RT_NOCRT(fclose)(FILE *pFile)
+{
+    int rc = RTStrmClose(pFile);
+    if (RT_SUCCESS(rc))
+        return 0;
+    errno = RTErrConvertToErrno(rc);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fclose);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fdopen.cpp b/src/VBox/Runtime/r3/nocrt-fdopen.cpp
new file mode 100644
index 00000000..8ecef72f
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fdopen.cpp
@@ -0,0 +1,66 @@
+/* $Id: nocrt-fdopen.cpp $ */
+/** @file
+ * IPRT - No-CRT - fdopen().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/file.h>
+#include <iprt/stream.h>
+
+
+#undef fdopen
+FILE *RT_NOCRT(fdopen)(int fd, const char *pszMode)
+{
+    RTFILE hFile = NIL_RTFILE;
+    int rc = RTFileFromNative(&hFile, fd);
+    if (RT_SUCCESS(rc))
+    {
+        PRTSTREAM pStrm = NULL;
+        rc = RTStrmOpenFileHandle(hFile, pszMode, 0, &pStrm);
+        if (RT_SUCCESS(rc))
+            return pStrm;
+    }
+    errno = RTErrConvertToErrno(rc);
+    return NULL;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fdopen);
+
diff --git a/src/VBox/Runtime/r3/nocrt-ferror.cpp b/src/VBox/Runtime/r3/nocrt-ferror.cpp
new file mode 100644
index 00000000..b566cd87
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-ferror.cpp
@@ -0,0 +1,57 @@
+/* $Id: nocrt-ferror.cpp $ */
+/** @file
+ * IPRT - No-CRT - ferror().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef ferror
+int  RT_NOCRT(ferror)(FILE *pFile)
+{
+    int rc = RTStrmError(pFile);
+    if (RT_SUCCESS(rc))
+        return 0;
+    return 1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(ferror);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fflush.cpp b/src/VBox/Runtime/r3/nocrt-fflush.cpp
new file mode 100644
index 00000000..2535da4b
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fflush.cpp
@@ -0,0 +1,59 @@
+/* $Id: nocrt-fflush.cpp $ */
+/** @file
+ * IPRT - No-CRT - fflush().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fflush
+int RT_NOCRT(fflush)(FILE *pFile)
+{
+    int rc = RTStrmFlush(pFile);
+    if (RT_SUCCESS(rc))
+        return 0;
+    errno = RTErrConvertToErrno(rc);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fflush);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fgetc.cpp b/src/VBox/Runtime/r3/nocrt-fgetc.cpp
new file mode 100644
index 00000000..cbb0cfdc
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fgetc.cpp
@@ -0,0 +1,61 @@
+/* $Id: nocrt-fgetc.cpp $ */
+/** @file
+ * IPRT - No-CRT - fgetc().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+/* Note! This is identical to the getc implemention. */
+#undef fgetc
+int RT_NOCRT(fgetc)(FILE *pFile)
+{
+    unsigned char ch;
+    int rc = RTStrmReadEx(pFile, &ch, 1, NULL);
+    if (RT_SUCCESS(rc))
+        return ch;
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fgetc);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fileno.cpp b/src/VBox/Runtime/r3/nocrt-fileno.cpp
new file mode 100644
index 00000000..506606a5
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fileno.cpp
@@ -0,0 +1,61 @@
+/* $Id: nocrt-fileno.cpp $ */
+/** @file
+ * IPRT - No-CRT - fileno().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/file.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fileno
+int RT_NOCRT(fileno)(FILE *pFile)
+{
+    RTFILE hFile;
+    int rc = RTStrmQueryFileHandle(pFile, &hFile);
+    if (RT_SUCCESS(rc))
+        return (int)RTFileToNative(hFile);
+    errno = EINVAL;
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fileno);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fopen.cpp b/src/VBox/Runtime/r3/nocrt-fopen.cpp
new file mode 100644
index 00000000..3231a765
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fopen.cpp
@@ -0,0 +1,60 @@
+/* $Id: nocrt-fopen.cpp $ */
+/** @file
+ * IPRT - No-CRT - fopen().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fopen
+FILE *RT_NOCRT(fopen)(const char *pszFilename, const char *pszMode)
+{
+    PRTSTREAM pStrm = NULL;
+    int rc = RTStrmOpen(pszFilename, pszMode, &pStrm);
+    if (RT_SUCCESS(rc))
+        return pStrm;
+    errno = RTErrConvertToErrno(rc);
+    return NULL;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fopen);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fputc.cpp b/src/VBox/Runtime/r3/nocrt-fputc.cpp
new file mode 100644
index 00000000..5e3e57c6
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fputc.cpp
@@ -0,0 +1,61 @@
+/* $Id: nocrt-fputc.cpp $ */
+/** @file
+ * IPRT - No-CRT - fputc().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+/* Note! This is identical to the putc implemention. */
+#undef fputc
+int RT_NOCRT(fputc)(int iChar, FILE *pFile)
+{
+    unsigned char ch = (unsigned char)iChar;
+    int rc = RTStrmWriteEx(pFile, &ch, 1, NULL);
+    if (RT_SUCCESS(rc))
+        return ch;
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fputc);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fputs.cpp b/src/VBox/Runtime/r3/nocrt-fputs.cpp
new file mode 100644
index 00000000..64656496
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fputs.cpp
@@ -0,0 +1,63 @@
+/* $Id: nocrt-fputs.cpp $ */
+/** @file
+ * IPRT - No-CRT - fputs().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/nocrt/limits.h>
+#include <iprt/nocrt/string.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fputs
+int RT_NOCRT(fputs)(const char *psz, FILE *pFile)
+{
+    /* We're using RTStrmPutStr here for the benefit of console output optimization. */
+    size_t cch = strlen(psz);
+    int rc = RTStrmPutStr(pFile, psz);
+    if (RT_SUCCESS(rc))
+        return (int)RT_MIN(cch, (size_t)INT_MAX);
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fputs);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fread.cpp b/src/VBox/Runtime/r3/nocrt-fread.cpp
new file mode 100644
index 00000000..9c0e8b47
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fread.cpp
@@ -0,0 +1,63 @@
+/* $Id: nocrt-fread.cpp $ */
+/** @file
+ * IPRT - No-CRT - fread().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fread
+size_t RT_NOCRT(fread)(void *pvBuf, size_t cbItem, size_t cItems, FILE *pFile)
+{
+    size_t cbToRead = cbItem * cItems;
+    AssertReturnStmt(cbToRead >= cbItem && cbItem >= cItems, errno = ERANGE, 0);
+    size_t cbRead = 0;
+    int rc = RTStrmReadEx(pFile, pvBuf, cbToRead, &cbRead);
+    if (RT_SUCCESS(rc))
+        return cbRead;
+    errno = RTErrConvertToErrno(rc);
+    return 0;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fread);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fseek.cpp b/src/VBox/Runtime/r3/nocrt-fseek.cpp
new file mode 100644
index 00000000..2548c926
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fseek.cpp
@@ -0,0 +1,59 @@
+/* $Id: nocrt-fseek.cpp $ */
+/** @file
+ * IPRT - No-CRT - fseek().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fseek
+int RT_NOCRT(fseek)(FILE *pFile, long off, int iMethod)
+{
+    int rc = RTStrmSeek(pFile, off, (uint32_t)iMethod);
+    if (RT_SUCCESS(rc))
+        return 0;
+    errno = RTErrConvertToErrno(rc);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fseek);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fseeko.cpp b/src/VBox/Runtime/r3/nocrt-fseeko.cpp
new file mode 100644
index 00000000..bdeb6a9e
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fseeko.cpp
@@ -0,0 +1,59 @@
+/* $Id: nocrt-fseeko.cpp $ */
+/** @file
+ * IPRT - No-CRT - fseeko().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fseeko
+int RT_NOCRT(fseeko)(FILE *pFile, off_t off, int iMethod)
+{
+    int rc = RTStrmSeek(pFile, off, (uint32_t)iMethod);
+    if (RT_SUCCESS(rc))
+        return 0;
+    errno = RTErrConvertToErrno(rc);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fseeko);
+
diff --git a/src/VBox/Runtime/r3/nocrt-ftell.cpp b/src/VBox/Runtime/r3/nocrt-ftell.cpp
new file mode 100644
index 00000000..c8acc950
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-ftell.cpp
@@ -0,0 +1,65 @@
+/* $Id: nocrt-ftell.cpp $ */
+/** @file
+ * IPRT - No-CRT - ftell().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/nocrt/limits.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef ftell
+long RT_NOCRT(ftell)(FILE *pFile)
+{
+    RTFOFF off = RTStrmTell(pFile);
+    if (off >= 0)
+    {
+        if (off < LONG_MAX)
+            return (long)off;
+        errno = EOVERFLOW;
+    }
+    else
+        errno = RTErrConvertToErrno((int)off);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(ftell);
+
diff --git a/src/VBox/Runtime/r3/nocrt-ftello.cpp b/src/VBox/Runtime/r3/nocrt-ftello.cpp
new file mode 100644
index 00000000..0cf2b6d8
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-ftello.cpp
@@ -0,0 +1,60 @@
+/* $Id: nocrt-ftello.cpp $ */
+/** @file
+ * IPRT - No-CRT - ftello().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef ftello
+off_t RT_NOCRT(ftello)(FILE *pFile)
+{
+    RTFOFF off = RTStrmTell(pFile);
+    AssertCompile(sizeof(off_t) == sizeof(off));
+    if (off >= 0)
+        return off;
+    errno = RTErrConvertToErrno((int)off);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(ftello);
+
diff --git a/src/VBox/Runtime/r3/nocrt-fwrite.cpp b/src/VBox/Runtime/r3/nocrt-fwrite.cpp
new file mode 100644
index 00000000..05d108d2
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-fwrite.cpp
@@ -0,0 +1,63 @@
+/* $Id: nocrt-fwrite.cpp $ */
+/** @file
+ * IPRT - No-CRT - fwrite().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef fwrite
+size_t RT_NOCRT(fwrite)(void const *pvBuf, size_t cbItem, size_t cItems, FILE *pFile)
+{
+    size_t cbToWrite = cbItem * cItems;
+    AssertReturnStmt(cbToWrite >= cbItem && cbItem >= cItems, errno = ERANGE, 0);
+    size_t cbWritten = 0;
+    int rc = RTStrmWriteEx(pFile, pvBuf, cbToWrite, &cbWritten);
+    if (RT_SUCCESS(rc))
+        return cbWritten;
+    errno = RTErrConvertToErrno(rc);
+    return 0;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(fwrite);
+
diff --git a/src/VBox/Runtime/r3/nocrt-getc.cpp b/src/VBox/Runtime/r3/nocrt-getc.cpp
new file mode 100644
index 00000000..4f94cbdb
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-getc.cpp
@@ -0,0 +1,61 @@
+/* $Id: nocrt-getc.cpp $ */
+/** @file
+ * IPRT - No-CRT - getc().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+/* Note! This is identical to the fgetc implemention. */
+#undef getc
+int RT_NOCRT(getc)(FILE *pFile)
+{
+    unsigned char ch;
+    int rc = RTStrmReadEx(pFile, &ch, 1, NULL);
+    if (RT_SUCCESS(rc))
+        return ch;
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(getc);
+
diff --git a/src/VBox/Runtime/r3/nocrt-per-thread-1.cpp b/src/VBox/Runtime/r3/nocrt-per-thread-1.cpp
new file mode 100644
index 00000000..52bccab8
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-per-thread-1.cpp
@@ -0,0 +1,58 @@
+/* $Id: nocrt-per-thread-1.cpp $ */
+/** @file
+ * IPRT - No-Crt - Per Thread Data, TLS index.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The TLS index for the no-CRT per thread data.  */
+RTTLS volatile      g_iTlsRtNoCrtPerThread = NIL_RTTLS;
+
+/** The TLS entry of an IPRT thread points to this during the cleanup (paranoia). */
+RTNOCRTTHREADDATA   g_RtNoCrtPerThreadDummy =
+{
+    { NULL, NULL },
+    RTNOCRTTHREADDATA::kAllocType_CleanupDummy,
+    0,
+    NULL
+};
+
diff --git a/src/VBox/Runtime/r3/nocrt-per-thread-2.cpp b/src/VBox/Runtime/r3/nocrt-per-thread-2.cpp
new file mode 100644
index 00000000..9179d33a
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-per-thread-2.cpp
@@ -0,0 +1,238 @@
+/* $Id: nocrt-per-thread-2.cpp $ */
+/** @file
+ * IPRT - No-Crt - Per Thread Data, Managment code
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+#include <iprt/asm.h>
+#include <iprt/critsect.h>
+#include <iprt/errcore.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/thread.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Init/term once state. */
+static RTONCE               g_NoCrtPerThreadOnce = RTONCE_INITIALIZER;
+
+/** List of heap allocations (PRTNOCRTTHREADDATA).   */
+static RTLISTANCHOR         g_NoCrtPerThreadHeapList;
+/** Critical section protecting g_NoCrtPerThreadHeapList. */
+static RTCRITSECT           g_NoCrtPerThreadCritSect;
+
+/** Allocation bitmap for g_aNoCrtPerThreadStatic.
+ *
+ * In debug builds we only have one slot here, so we have a better chance of
+ * testing the heap code path. */
+#ifdef DEBUG
+static uint32_t volatile    g_fNoCrtPerThreadStaticAlloc = UINT32_C(0xffffefff);
+#else
+static uint32_t volatile    g_fNoCrtPerThreadStaticAlloc = 0;
+#endif
+/* Static allocations to avoid the heap and associate slowness. */
+static RTNOCRTTHREADDATA    g_aNoCrtPerThreadStatic[32];
+
+
+/**
+ * @callback_method_impl{FNRTTLSDTOR}
+ */
+static DECLCALLBACK(void) rtNoCrtPerThreadDtor(void *pvValue)
+{
+    PRTNOCRTTHREADDATA pNoCrtData = (PRTNOCRTTHREADDATA)pvValue;
+    if (pNoCrtData->enmAllocType == RTNOCRTTHREADDATA::kAllocType_Heap)
+    {
+        AssertReturnVoid(RTOnceWasInitialized(&g_NoCrtPerThreadOnce));
+
+        RTCritSectEnter(&g_NoCrtPerThreadCritSect); /* timeout? */
+
+        RTListNodeRemove(&pNoCrtData->ListEntry);
+        pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_End;
+
+        RTCritSectLeave(&g_NoCrtPerThreadCritSect);
+
+        RTMemFree(pNoCrtData);
+    }
+    else if (pNoCrtData->enmAllocType == RTNOCRTTHREADDATA::kAllocType_Static)
+    {
+        size_t iSlot = (size_t)(pNoCrtData - &g_aNoCrtPerThreadStatic[0]);
+        AssertReturnVoid(iSlot < RT_ELEMENTS(g_aNoCrtPerThreadStatic));
+
+        pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_Invalid;
+        ASMAtomicAndU32(&g_fNoCrtPerThreadStaticAlloc, ~(uint32_t)iSlot);
+    }
+}
+
+
+/**
+ * @callback_method_impl{FNRTONCE}
+ */
+static DECLCALLBACK(int32_t) rtNoCrtPerThreadInit(void *pvUser)
+{
+    RTListInit(&g_NoCrtPerThreadHeapList);
+
+    RTTLS iTls = NIL_RTTLS;
+    int rc = RTTlsAllocEx(&iTls, rtNoCrtPerThreadDtor);
+    if (iTls != NIL_RTTLS)
+    {
+        rc = RTCritSectInit(&g_NoCrtPerThreadCritSect);
+        if (RT_SUCCESS(rc))
+        {
+            g_iTlsRtNoCrtPerThread = iTls;
+            return VINF_SUCCESS;
+        }
+        RTTlsFree(iTls);
+    }
+    RT_NOREF(pvUser);
+    return rc;
+}
+
+
+/**
+ * @callback_method_impl{FNRTONCECLEANUP}
+ */
+static DECLCALLBACK(void) rtNoCrtPerThreadCleanup(void *pvUser, bool fLazyCleanUpOk)
+{
+    RT_NOREF(pvUser);
+    if (fLazyCleanUpOk)
+        return;
+
+    /*
+     * First destroy the TLS entry.
+     */
+    RTTLS iTls = g_iTlsRtNoCrtPerThread;
+    g_iTlsRtNoCrtPerThread = NIL_RTTLS;
+    int rc = RTTlsFree(iTls);
+    AssertRC(rc);
+
+    /*
+     * Then destroy the critical section and free all entries in the list.
+     */
+    RTCritSectDelete(&g_NoCrtPerThreadCritSect);
+
+    PRTNOCRTTHREADDATA pNoCrtData;
+    while ((pNoCrtData = RTListRemoveFirst(&g_NoCrtPerThreadHeapList, RTNOCRTTHREADDATA, ListEntry)) != NULL)
+    {
+        AssertContinue(pNoCrtData->enmAllocType == RTNOCRTTHREADDATA::kAllocType_Heap);
+        pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_End;
+        RTMemFree(pNoCrtData);
+    }
+}
+
+PRTNOCRTTHREADDATA rtNoCrtThreadDataGet(void)
+{
+    int rc = RTOnceEx(&g_NoCrtPerThreadOnce, rtNoCrtPerThreadInit, rtNoCrtPerThreadCleanup, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * We typically have an entry already.
+         */
+        PRTNOCRTTHREADDATA pNoCrtData = (PRTNOCRTTHREADDATA)RTTlsGet(g_iTlsRtNoCrtPerThread);
+        if (pNoCrtData)
+        {
+            AssertReturn(   pNoCrtData->enmAllocType > RTNOCRTTHREADDATA::kAllocType_Invalid
+                         && pNoCrtData->enmAllocType < RTNOCRTTHREADDATA::kAllocType_End,
+                         NULL);
+            return pNoCrtData;
+        }
+
+        /*
+         * Okay, allocate a new entry first using some of the statically allocated
+         * ones then falling back on heap allocations.
+         */
+        for (;;)
+        {
+            uint32_t const  fAlloc = ASMAtomicUoReadU32(&g_fNoCrtPerThreadStaticAlloc);
+            uint32_t        iSlot  = ASMBitFirstSetU32(~fAlloc);
+            if (iSlot != 0)
+                iSlot--;
+            else
+                break;
+            if (ASMAtomicCmpXchgU32(&g_fNoCrtPerThreadStaticAlloc, fAlloc | RT_BIT_32(iSlot), fAlloc))
+            {
+                pNoCrtData = &g_aNoCrtPerThreadStatic[iSlot];
+
+                /* Init the entry in case it's being re-used: */
+                Assert(pNoCrtData->enmAllocType == RTNOCRTTHREADDATA::kAllocType_Invalid);
+                rc = RTTlsSet(g_iTlsRtNoCrtPerThread, pNoCrtData);
+                AssertRC(rc);
+                if (RT_SUCCESS(rc))
+                {
+                    pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_Static;
+                    RTListInit(&pNoCrtData->ListEntry);
+                    pNoCrtData->iErrno      = 0;
+                    pNoCrtData->pszStrToken = NULL;
+                    return pNoCrtData;
+                }
+
+                ASMAtomicOrU32(&g_fNoCrtPerThreadStaticAlloc, RT_BIT_32(iSlot));
+                return NULL;
+            }
+            ASMNopPause();
+        }
+
+        /*
+         * Heap.
+         */
+        pNoCrtData = (PRTNOCRTTHREADDATA)RTMemAllocZ(sizeof(*pNoCrtData));
+        if (pNoCrtData)
+        {
+            pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_Heap;
+
+            RTCritSectEnter(&g_NoCrtPerThreadCritSect);
+            RTListAppend(&g_NoCrtPerThreadHeapList, &pNoCrtData->ListEntry);
+            RTCritSectLeave(&g_NoCrtPerThreadCritSect);
+
+            rc = RTTlsSet(g_iTlsRtNoCrtPerThread, pNoCrtData);
+            AssertRC(rc);
+            if (RT_SUCCESS(rc))
+                return pNoCrtData;
+
+            RTCritSectEnter(&g_NoCrtPerThreadCritSect);
+            RTListNodeRemove(&pNoCrtData->ListEntry);
+            RTCritSectLeave(&g_NoCrtPerThreadCritSect);
+
+            pNoCrtData->enmAllocType = RTNOCRTTHREADDATA::kAllocType_End;
+            RTMemFree(pNoCrtData);
+        }
+    }
+    return NULL;
+}
+
diff --git a/src/VBox/Runtime/r3/nocrt-putc.cpp b/src/VBox/Runtime/r3/nocrt-putc.cpp
new file mode 100644
index 00000000..8f334057
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-putc.cpp
@@ -0,0 +1,61 @@
+/* $Id: nocrt-putc.cpp $ */
+/** @file
+ * IPRT - No-CRT - putc().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+/* Note! This is identical to the fputc implemention. */
+#undef putc
+int RT_NOCRT(putc)(int iChar, FILE *pFile)
+{
+    unsigned char ch = (unsigned char)iChar;
+    int rc = RTStrmWriteEx(pFile, &ch, 1, NULL);
+    if (RT_SUCCESS(rc))
+        return ch;
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(putc);
+
diff --git a/src/VBox/Runtime/r3/nocrt-puts.cpp b/src/VBox/Runtime/r3/nocrt-puts.cpp
new file mode 100644
index 00000000..11f90e52
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-puts.cpp
@@ -0,0 +1,68 @@
+/* $Id: nocrt-puts.cpp $ */
+/** @file
+ * IPRT - No-CRT - puts().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/nocrt/string.h>
+#include <iprt/nocrt/limits.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef puts
+int RT_NOCRT(puts)(const char *psz)
+{
+    /* We're using RTStrmPutStr here for the benefit of console output optimization. */
+    size_t cch = strlen(psz);
+    int rc = RTStrmPutStr(g_pStdOut, psz);
+    if (RT_SUCCESS(rc))
+    {
+        /** @todo This isn't entirely perfect wrt multithreading. */
+        rc = RTStrmPutStr(g_pStdOut, "\n");
+        if (RT_SUCCESS(rc))
+            return (int)RT_MIN(cch + 1, (size_t)INT_MAX);
+    }
+    errno = RTErrConvertToErrno(rc);
+    return RT_NOCRT_EOF;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(puts);
+
diff --git a/src/VBox/Runtime/r3/nocrt-setvbuf.cpp b/src/VBox/Runtime/r3/nocrt-setvbuf.cpp
new file mode 100644
index 00000000..76e0e46c
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-setvbuf.cpp
@@ -0,0 +1,72 @@
+/* $Id: nocrt-setvbuf.cpp $ */
+/** @file
+ * IPRT - No-CRT - setvbuf().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/stream.h>
+
+
+#undef setvbuf
+int RT_NOCRT(setvbuf)(FILE *pFile, char *pchBuf, int iBufferingType, size_t cbBuf)
+{
+    Assert(!pchBuf); RT_NOREF(pchBuf); /* ignored */
+    Assert(!cbBuf);  RT_NOREF(cbBuf);  /* ignored */
+
+    RTSTRMBUFMODE enmBufMode;
+    switch (iBufferingType)
+    {
+        case _IOFBF: enmBufMode = RTSTRMBUFMODE_FULL; break;
+        case _IOLBF: enmBufMode = RTSTRMBUFMODE_LINE; break;
+        case _IONBF: enmBufMode = RTSTRMBUFMODE_UNBUFFERED; break;
+        default: AssertFailedReturnStmt(errno = EINVAL, -1);
+    }
+
+    int rc = RTStrmSetBufferingMode(pFile, enmBufMode);
+    if (RT_SUCCESS(rc))
+        return 0;
+    errno = RTErrConvertToErrno(rc);
+    return -1;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(setvbuf);
+
diff --git a/src/VBox/Runtime/r3/nocrt-tmpfile.cpp b/src/VBox/Runtime/r3/nocrt-tmpfile.cpp
new file mode 100644
index 00000000..f8064326
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-tmpfile.cpp
@@ -0,0 +1,59 @@
+/* $Id: nocrt-tmpfile.cpp $ */
+/** @file
+ * IPRT - No-CRT - tmpfile().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+
+
+#undef tmpfile
+FILE *RT_NOCRT(tmpfile)(void)
+{
+    FILE *pFile = NULL;
+    errno_t rc = tmpfile_s(&pFile);
+    if (rc == 0)
+        return pFile;
+    errno = rc;
+    return NULL;
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(tmpfile);
+
diff --git a/src/VBox/Runtime/r3/nocrt-tmpfile_s.cpp b/src/VBox/Runtime/r3/nocrt-tmpfile_s.cpp
new file mode 100644
index 00000000..dad6ee7a
--- /dev/null
+++ b/src/VBox/Runtime/r3/nocrt-tmpfile_s.cpp
@@ -0,0 +1,72 @@
+/* $Id: nocrt-tmpfile_s.cpp $ */
+/** @file
+ * IPRT - No-CRT - tmpfile_s().
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define IPRT_NO_CRT_FOR_3RD_PARTY
+#include "internal/nocrt.h"
+#include <iprt/nocrt/stdio.h>
+#include <iprt/nocrt/errno.h>
+#include <iprt/errcore.h>
+#include <iprt/file.h>
+#include <iprt/path.h>
+#include <iprt/stream.h>
+
+
+#undef tmpfile_s
+errno_t RT_NOCRT(tmpfile_s)(FILE **ppFile)
+{
+    char   szPath[RTPATH_MAX]; /* The file is inaccessible by this name, it's just for RTFileOpenTemp's use really. */
+    RTFILE hFile = NIL_RTFILE;
+    int rc = RTFileOpenTemp(&hFile, szPath, sizeof(szPath),
+                            RTFILE_O_CREATE | RTFILE_O_READWRITE | RTFILE_O_DENY_NONE | RTFILE_O_TEMP_AUTO_DELETE);
+    if (RT_SUCCESS(rc))
+    {
+        PRTSTREAM pFile = NULL;
+        rc = RTStrmOpenFileHandle(hFile, "w+b", 0 /*fFlags*/, &pFile);
+        if (RT_SUCCESS(rc))
+        {
+            *ppFile = pFile;
+            return 0;
+        }
+        RTFileClose(hFile);
+    }
+    return RTErrConvertToErrno(rc);
+}
+RT_ALIAS_AND_EXPORT_NOCRT_SYMBOL(tmpfile_s);
+
diff --git a/src/VBox/Runtime/r3/nt/Makefile.kup b/src/VBox/Runtime/r3/nt/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/Makefile.kup
diff --git a/src/VBox/Runtime/r3/nt/RTFileQueryFsSizes-nt.cpp b/src/VBox/Runtime/r3/nt/RTFileQueryFsSizes-nt.cpp
new file mode 100644
index 00000000..63a88211
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/RTFileQueryFsSizes-nt.cpp
@@ -0,0 +1,102 @@
+/* $Id: RTFileQueryFsSizes-nt.cpp $ */
+/** @file
+ * IPRT - RTFileQueryFsSizes, Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include "internal-r3-nt.h"
+
+#include <iprt/file.h>
+#include <iprt/errcore.h>
+
+
+
+RTR3DECL(int) RTFileQueryFsSizes(RTFILE hFile, PRTFOFF pcbTotal, RTFOFF *pcbFree,
+                                 uint32_t *pcbBlock, uint32_t *pcbSector)
+{
+    int rc;
+
+    /*
+     * Get the volume information.
+     */
+    FILE_FS_SIZE_INFORMATION FsSizeInfo;
+    IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS rcNt = NtQueryVolumeInformationFile((HANDLE)RTFileToNative(hFile), &Ios,
+                                                 &FsSizeInfo, sizeof(FsSizeInfo), FileFsSizeInformation);
+    if (NT_SUCCESS(rcNt))
+    {
+        /*
+         * Calculate the return values.
+         */
+        if (pcbTotal)
+        {
+            *pcbTotal = FsSizeInfo.TotalAllocationUnits.QuadPart
+                      * FsSizeInfo.SectorsPerAllocationUnit
+                      * FsSizeInfo.BytesPerSector;
+            if (   *pcbTotal / FsSizeInfo.SectorsPerAllocationUnit / FsSizeInfo.BytesPerSector
+                != FsSizeInfo.TotalAllocationUnits.QuadPart)
+                *pcbTotal = UINT64_MAX;
+        }
+
+        if (pcbFree)
+        {
+            *pcbFree = FsSizeInfo.AvailableAllocationUnits.QuadPart
+                     * FsSizeInfo.SectorsPerAllocationUnit
+                     * FsSizeInfo.BytesPerSector;
+            if (   *pcbFree / FsSizeInfo.SectorsPerAllocationUnit / FsSizeInfo.BytesPerSector
+                != FsSizeInfo.AvailableAllocationUnits.QuadPart)
+                *pcbFree = UINT64_MAX;
+        }
+
+        rc = VINF_SUCCESS;
+        if (pcbBlock)
+        {
+            *pcbBlock  = FsSizeInfo.SectorsPerAllocationUnit * FsSizeInfo.BytesPerSector;
+            if (*pcbBlock / FsSizeInfo.BytesPerSector != FsSizeInfo.SectorsPerAllocationUnit)
+                rc = VERR_OUT_OF_RANGE;
+        }
+
+        if (pcbSector)
+            *pcbSector = FsSizeInfo.BytesPerSector;
+    }
+    else
+        rc = RTErrConvertFromNtStatus(rcNt);
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/nt/RTFileSetMode-r3-nt.cpp b/src/VBox/Runtime/r3/nt/RTFileSetMode-r3-nt.cpp
new file mode 100644
index 00000000..2ec31d14
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/RTFileSetMode-r3-nt.cpp
@@ -0,0 +1,92 @@
+/* $Id: RTFileSetMode-r3-nt.cpp $ */
+/** @file
+ * IPRT - RTFileSetMode, Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include "internal-r3-nt.h"
+
+#include <iprt/file.h>
+#include <iprt/err.h>
+
+#include "internal/fs.h"
+
+
+/**
+ * Common worker for RTFileSetMode, RTPathSetMode and RTDirRelPathSetMode.
+ *
+ * @returns IPRT status code.
+ * @param   hNativeFile The NT handle to the file system object.
+ * @param   fMode       Valid and normalized file mode mask to set.
+ */
+DECLHIDDEN(int) rtNtFileSetModeWorker(HANDLE hNativeFile, RTFMODE fMode)
+{
+    IO_STATUS_BLOCK         Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    FILE_BASIC_INFORMATION  BasicInfo;
+    BasicInfo.CreationTime.QuadPart   = 0;
+    BasicInfo.ChangeTime.QuadPart     = 0;
+    BasicInfo.LastAccessTime.QuadPart = 0;
+    BasicInfo.LastWriteTime.QuadPart  = 0;
+    BasicInfo.FileAttributes          = (fMode & ~(  RTFS_DOS_NT_ENCRYPTED
+                                                   | RTFS_DOS_NT_COMPRESSED
+                                                   | RTFS_DOS_NT_REPARSE_POINT
+                                                   | RTFS_DOS_NT_SPARSE_FILE
+                                                   | RTFS_DOS_NT_DEVICE
+                                                   | RTFS_DOS_DIRECTORY)
+                                               & RTFS_DOS_MASK_NT)
+                                      >> RTFS_DOS_SHIFT;
+    Assert(!(BasicInfo.FileAttributes & ~0x31a7U /* FILE_ATTRIBUTE_VALID_SET_FLAGS */));
+    if (!BasicInfo.FileAttributes)
+        BasicInfo.FileAttributes |= FILE_ATTRIBUTE_NORMAL;
+
+    NTSTATUS rcNt = NtSetInformationFile(hNativeFile, &Ios, &BasicInfo, sizeof(BasicInfo), FileBasicInformation);
+    if (NT_SUCCESS(rcNt))
+        return VINF_SUCCESS;
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
+
+RTDECL(int) RTFileSetMode(RTFILE hFile, RTFMODE fMode)
+{
+    HANDLE hNative = (HANDLE)RTFileToNative(hFile);
+    AssertReturn(hNative != RTNT_INVALID_HANDLE_VALUE, VERR_INVALID_HANDLE);
+    fMode = rtFsModeNormalize(fMode, NULL, 0, RTFS_TYPE_FILE);
+    AssertReturn(rtFsModeIsValidPermissions(fMode), VERR_INVALID_FMODE);
+
+    return rtNtFileSetModeWorker(hNative, fMode);
+}
diff --git a/src/VBox/Runtime/r3/nt/RTPathQueryInfo-nt.cpp b/src/VBox/Runtime/r3/nt/RTPathQueryInfo-nt.cpp
new file mode 100644
index 00000000..a7b6459b
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/RTPathQueryInfo-nt.cpp
@@ -0,0 +1,680 @@
+/* $Id: RTPathQueryInfo-nt.cpp $ */
+/** @file
+ * IPRT - RTPathQueryInfo[Ex], Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include "internal-r3-nt.h"
+
+#include <iprt/path.h>
+#include <iprt/err.h>
+#include <iprt/time.h>
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Helper for comparing a UNICODE_STRING with a string litteral. */
+#define ARE_UNICODE_STRINGS_EQUAL(a_UniStr, a_wszType) \
+    (   (a_UniStr)->Length == sizeof(a_wszType) - sizeof(RTUTF16) \
+     && memcmp((a_UniStr)->Buffer, a_wszType, sizeof(a_wszType) - sizeof(RTUTF16)) == 0)
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+typedef NTSTATUS (NTAPI *PFNNTQUERYFULLATTRIBUTESFILE)(struct _OBJECT_ATTRIBUTES *, struct _FILE_NETWORK_OPEN_INFORMATION *);
+extern PFNNTQUERYFULLATTRIBUTESFILE g_pfnNtQueryFullAttributesFile; /* init-win.cpp */
+
+
+/* ASSUMES FileID comes after ShortName and the structs are identical up to that point. */
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, NextEntryOffset, FILE_ID_BOTH_DIR_INFORMATION, NextEntryOffset);
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileIndex      , FILE_ID_BOTH_DIR_INFORMATION, FileIndex      );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, CreationTime   , FILE_ID_BOTH_DIR_INFORMATION, CreationTime   );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, LastAccessTime , FILE_ID_BOTH_DIR_INFORMATION, LastAccessTime );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, LastWriteTime  , FILE_ID_BOTH_DIR_INFORMATION, LastWriteTime  );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ChangeTime     , FILE_ID_BOTH_DIR_INFORMATION, ChangeTime     );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, EndOfFile      , FILE_ID_BOTH_DIR_INFORMATION, EndOfFile      );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, AllocationSize , FILE_ID_BOTH_DIR_INFORMATION, AllocationSize );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileAttributes , FILE_ID_BOTH_DIR_INFORMATION, FileAttributes );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileNameLength , FILE_ID_BOTH_DIR_INFORMATION, FileNameLength );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, EaSize         , FILE_ID_BOTH_DIR_INFORMATION, EaSize         );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ShortNameLength, FILE_ID_BOTH_DIR_INFORMATION, ShortNameLength);
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ShortName      , FILE_ID_BOTH_DIR_INFORMATION, ShortName      );
+
+
+
+/**
+ * Splits up an NT path into directory and filename.
+ *
+ * @param   pNtName             The path to split.
+ * @param   pNtParent           Where to return the directory path.
+ * @param   pNtFilename         Where to return the filename part.
+ * @param   fNoParentDirSlash   Whether to make sure the directory path doesn't
+ *                              end with a slash (except root).
+ */
+static void ntPathNtSplitName(UNICODE_STRING const *pNtName, UNICODE_STRING *pNtParent, UNICODE_STRING *pNtFilename,
+                              bool fNoParentDirSlash)
+{
+    PRTUTF16 pwszBuffer = pNtName->Buffer;
+    size_t   off        = pNtName->Length / sizeof(RTUTF16);
+
+    /* Skip trailing slash if present. */
+    if (   off > 0
+        && pwszBuffer[off - 1] == '\\')
+        off--;
+
+    /* Find the slash before that. */
+    RTUTF16  wc;
+    while (   off > 0
+           && (wc = pwszBuffer[off - 1]) != '\\'
+           && wc != '/')
+        off--;
+    if (off != 0)
+    {
+        pNtParent->Buffer        = pwszBuffer;
+        pNtParent->MaximumLength = pNtParent->Length = (USHORT)(off * sizeof(RTUTF16));
+    }
+    else
+    {
+        AssertFailed(); /* This is impossible and won't work (NT doesn't know '.' or '..').  */
+        /** @todo query the whole path as it is possible relative. Use the buffer for
+         *        temporary name storage. */
+        pNtParent->Buffer        = L".";
+        pNtParent->Length        = 1 * sizeof(RTUTF16);
+        pNtParent->MaximumLength = 2 * sizeof(RTUTF16);
+    }
+
+    pNtFilename->Buffer        = &pwszBuffer[off];
+    pNtFilename->Length        = pNtName->Length        - (USHORT)(off * sizeof(RTUTF16));
+    pNtFilename->MaximumLength = pNtName->MaximumLength - (USHORT)(off * sizeof(RTUTF16));
+
+    while (   fNoParentDirSlash
+           && pNtParent->Length > sizeof(RTUTF16)
+           && pNtParent->Buffer[pNtParent->Length / sizeof(RTUTF16) - 1] == '\\')
+        pNtParent->Length -= sizeof(RTUTF16);
+}
+
+
+/**
+ * Deals with enmAddAttr != RTFSOBJATTRADD_UNIX.
+ *
+ * @returns IPRT status code (usually @a rc).
+ * @param   rc                  The return code.
+ * @param   pObjInfo            The info to complete.
+ * @param   enmAddAttr          What to complete it with.  Caller should fill in
+ *                              RTFSOBJATTRADD_UNIX.
+ */
+static int rtPathNtQueryInfoFillInDummyData(int rc, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
+{
+    switch (enmAddAttr)
+    {
+        case RTFSOBJATTRADD_UNIX:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+            break;
+
+        case RTFSOBJATTRADD_NOTHING:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_NOTHING;
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+            pObjInfo->Attr.u.UnixOwner.uid        = NIL_RTUID;
+            pObjInfo->Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+            pObjInfo->Attr.u.UnixGroup.gid        = NIL_RTGID;
+            pObjInfo->Attr.u.UnixGroup.szName[0]  = '\0';
+            break;
+
+        case RTFSOBJATTRADD_EASIZE:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+            pObjInfo->Attr.u.EASize.cb            = 0;
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            rc = VERR_INTERNAL_ERROR;
+    }
+    return rc;
+}
+
+
+/**
+ * Deal with getting info about something that could be in a directory object.
+ *
+ * @returns IPRT status code
+ * @param   pObjAttr        The NT object attribute.
+ * @param   pObjInfo        Where to return the info.
+ * @param   enmAddAttr      Which extra attributes to get (/fake).
+ * @param   fFlags          The flags.
+ * @param   pvBuf           Query buffer space.
+ * @param   cbBuf           Size of the buffer.  ASSUMES lots of space.
+ * @param   rcNtCaller      The status code that got us here.
+ */
+static int rtPathNtQueryInfoInDirectoryObject(OBJECT_ATTRIBUTES *pObjAttr, PRTFSOBJINFO pObjInfo,
+                                              RTFSOBJATTRADD enmAddAttr, uint32_t fFlags,
+                                              void *pvBuf, size_t cbBuf, NTSTATUS rcNtCaller)
+{
+    RT_NOREF(fFlags);
+
+    /*
+     * Special case: Root dir.
+     */
+    if (   pObjAttr->RootDirectory == NULL
+        && pObjAttr->ObjectName->Length == sizeof(RTUTF16)
+        && pObjAttr->ObjectName->Buffer[0] == '\\')
+    {
+        pObjInfo->cbObject    = 0;
+        pObjInfo->cbAllocated = 0;
+        RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         0);
+        RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        0);
+        RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  0);
+        RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        0);
+        pObjInfo->Attr.fMode = RTFS_DOS_DIRECTORY | RTFS_TYPE_DIRECTORY | 0777;
+        return rtPathNtQueryInfoFillInDummyData(VINF_SUCCESS, pObjInfo, enmAddAttr);
+    }
+
+    /*
+     * We must open and scan the parent directory object.
+     */
+    UNICODE_STRING NtDirName;
+    UNICODE_STRING NtDirEntry;
+    ntPathNtSplitName(pObjAttr->ObjectName, &NtDirName, &NtDirEntry, true /*fNoParentDirSlash*/);
+
+    while (   NtDirEntry.Length > sizeof(RTUTF16)
+           && NtDirEntry.Buffer[NtDirEntry.Length / sizeof(RTUTF16) - 1] == '\\')
+        NtDirEntry.Length -= sizeof(RTUTF16);
+
+    pObjAttr->ObjectName = &NtDirName;
+    HANDLE   hDir = RTNT_INVALID_HANDLE_VALUE;
+    NTSTATUS rcNt = NtOpenDirectoryObject(&hDir, DIRECTORY_QUERY | DIRECTORY_TRAVERSE, pObjAttr);
+    if (NT_SUCCESS(rcNt))
+    {
+        ULONG uObjDirCtx = 0;
+        for (;;)
+        {
+            ULONG cbReturned = 0;
+            rcNt = NtQueryDirectoryObject(hDir,
+                                          pvBuf,
+                                          (ULONG)cbBuf,
+                                          FALSE /*ReturnSingleEntry */,
+                                          FALSE /*RestartScan*/,
+                                          &uObjDirCtx,
+                                          &cbReturned);
+            if (!NT_SUCCESS(rcNt))
+                break;
+
+            for (POBJECT_DIRECTORY_INFORMATION pObjDir = (POBJECT_DIRECTORY_INFORMATION)pvBuf;
+                 pObjDir->Name.Length != 0;
+                 pObjDir++)
+            {
+                if (   pObjDir->Name.Length == NtDirEntry.Length
+                    && memcmp(pObjDir->Name.Buffer, NtDirEntry.Buffer, NtDirEntry.Length) == 0)
+                {
+                    /*
+                     * Find it.  Fill in the info we've got and return (see similar code in direnum-r3-nt.cpp).
+                     */
+                    NtClose(hDir);
+
+                    pObjInfo->cbObject    = 0;
+                    pObjInfo->cbAllocated = 0;
+                    RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         0);
+                    RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        0);
+                    RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  0);
+                    RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        0);
+
+                    if (ARE_UNICODE_STRINGS_EQUAL(&pObjDir->TypeName, L"Directory"))
+                        pObjInfo->Attr.fMode = RTFS_DOS_DIRECTORY | RTFS_TYPE_DIRECTORY | 0777;
+                    else if (ARE_UNICODE_STRINGS_EQUAL(&pObjDir->TypeName, L"SymbolicLink"))
+                        pObjInfo->Attr.fMode = RTFS_DOS_NT_REPARSE_POINT | RTFS_TYPE_SYMLINK | 0777;
+                    else if (ARE_UNICODE_STRINGS_EQUAL(&pObjDir->TypeName, L"Device"))
+                        pObjInfo->Attr.fMode = RTFS_DOS_NT_DEVICE | RTFS_TYPE_DEV_CHAR | 0666;
+                    else
+                        pObjInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_FILE | 0666;
+
+                    pObjInfo->Attr.enmAdditional = enmAddAttr;
+                    return rtPathNtQueryInfoFillInDummyData(VINF_SUCCESS, pObjInfo, enmAddAttr);
+                }
+            }
+        }
+
+        NtClose(hDir);
+        if (rcNt == STATUS_NO_MORE_FILES || rcNt == STATUS_NO_MORE_ENTRIES || rcNt == STATUS_NO_SUCH_FILE)
+            return VERR_FILE_NOT_FOUND;
+    }
+    else
+        return RTErrConvertFromNtStatus(rcNtCaller);
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
+
+/**
+ * Queries information from a file or directory handle.
+ *
+ * This is shared between the RTPathQueryInfo, RTFileQueryInfo and
+ * RTDirQueryInfo code.
+ *
+ * @returns IPRT status code.
+ * @param   hFile               The handle to query information from.  Must have
+ *                              the necessary privileges.
+ * @param   pvBuf               Pointer to a scratch buffer.
+ * @param   cbBuf               The size of the buffer.  This must be large
+ *                              enough to hold a FILE_ALL_INFORMATION struct.
+ * @param   pObjInfo            Where to return information about the handle.
+ * @param   enmAddAttr          What extra info to return.
+ * @param   pszPath             The path if this is a file (for exe detect).
+ * @param   uReparseTag         The reparse tag number (0 if not applicable) for
+ *                              symlink detection/whatnot.
+ */
+DECLHIDDEN(int) rtPathNtQueryInfoFromHandle(HANDLE hFile, void *pvBuf, size_t cbBuf, PRTFSOBJINFO pObjInfo,
+                                            RTFSOBJATTRADD enmAddAttr, const char *pszPath, ULONG uReparseTag)
+{
+    Assert(cbBuf >= sizeof(FILE_ALL_INFORMATION));
+
+    /** @todo Try optimize this for when RTFSOBJATTRADD_UNIX isn't set? */
+    IO_STATUS_BLOCK  Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS rcNt = NtQueryInformationFile(hFile, &Ios, pvBuf, sizeof(FILE_ALL_INFORMATION), FileAllInformation);
+    if (   NT_SUCCESS(rcNt)
+        || rcNt == STATUS_BUFFER_OVERFLOW)
+    {
+        FILE_ALL_INFORMATION *pAllInfo = (FILE_ALL_INFORMATION *)pvBuf;
+        pObjInfo->cbObject    = pAllInfo->StandardInformation.EndOfFile.QuadPart;
+        pObjInfo->cbAllocated = pAllInfo->StandardInformation.AllocationSize.QuadPart;
+        RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         pAllInfo->BasicInformation.CreationTime.QuadPart);
+        RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        pAllInfo->BasicInformation.LastAccessTime.QuadPart);
+        RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  pAllInfo->BasicInformation.LastWriteTime.QuadPart);
+        RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        pAllInfo->BasicInformation.ChangeTime.QuadPart);
+        pObjInfo->Attr.fMode = rtFsModeFromDos(  (pAllInfo->BasicInformation.FileAttributes << RTFS_DOS_SHIFT)
+                                               & RTFS_DOS_MASK_NT,
+                                               pszPath, pszPath ? strlen(pszPath) : 0, uReparseTag, 0);
+        pObjInfo->Attr.enmAdditional = enmAddAttr;
+        if (enmAddAttr == RTFSOBJATTRADD_UNIX)
+        {
+            pObjInfo->Attr.u.Unix.uid             = ~0U;
+            pObjInfo->Attr.u.Unix.gid             = ~0U;
+            pObjInfo->Attr.u.Unix.cHardlinks      = RT_MAX(1, pAllInfo->StandardInformation.NumberOfLinks);
+            pObjInfo->Attr.u.Unix.INodeIdDevice   = 0; /* below */
+            pObjInfo->Attr.u.Unix.INodeId         = pAllInfo->InternalInformation.IndexNumber.QuadPart;
+            pObjInfo->Attr.u.Unix.fFlags          = 0;
+            pObjInfo->Attr.u.Unix.GenerationId    = 0;
+            pObjInfo->Attr.u.Unix.Device          = 0;
+
+            /* Get the serial number. */
+            rcNt = NtQueryVolumeInformationFile(hFile, &Ios, pvBuf, (ULONG)RT_MIN(cbBuf, _2K), FileFsVolumeInformation);
+            if (NT_SUCCESS(rcNt) || rcNt == STATUS_BUFFER_OVERFLOW)
+            {
+                FILE_FS_VOLUME_INFORMATION *pVolInfo = (FILE_FS_VOLUME_INFORMATION *)pvBuf;
+                pObjInfo->Attr.u.Unix.INodeIdDevice = pVolInfo->VolumeSerialNumber;
+            }
+        }
+
+        return rtPathNtQueryInfoFillInDummyData(VINF_SUCCESS, pObjInfo, enmAddAttr);
+    }
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
+
+/**
+ * Worker for RTPathQueryInfoEx and RTDirRelPathQueryInfo.
+ *
+ * @returns IPRT status code.
+ * @param   hRootDir            The root directory that pNtName is relative to.
+ * @param   pNtName             The NT path which we want to query info for.
+ * @param   pObjInfo            Where to return the info.
+ * @param   enmAddAttr          What additional info to get/fake.
+ * @param   fFlags              Query flags (RTPATH_F_XXX).
+ * @param   pszPath             The path for detecting executables and such.
+ *                              Pass empty string if not applicable/available.
+ */
+DECLHIDDEN(int) rtPathNtQueryInfoWorker(HANDLE hRootDir, UNICODE_STRING *pNtName, PRTFSOBJINFO pObjInfo,
+                                        RTFSOBJATTRADD enmAddAttr, uint32_t fFlags, const char *pszPath)
+{
+    /*
+     * There are a three different ways of doing this:
+     *   1. Use NtQueryFullAttributesFile to the get basic file info.
+     *   2. Open whatever the path points to and use NtQueryInformationFile.
+     *   3. Open the parent directory and use NtQueryDirectoryFile like RTDirReadEx.
+     *
+     * The first two options may fail with sharing violations or access denied,
+     * in which case we must use the last one as fallback.
+     */
+    HANDLE              hFile = RTNT_INVALID_HANDLE_VALUE;
+    IO_STATUS_BLOCK     Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS            rcNt;
+    OBJECT_ATTRIBUTES   ObjAttr;
+    union
+    {
+        FILE_NETWORK_OPEN_INFORMATION   NetOpenInfo;
+        FILE_ALL_INFORMATION            AllInfo;
+        FILE_FS_VOLUME_INFORMATION      VolInfo;
+        FILE_BOTH_DIR_INFORMATION       Both;
+        FILE_ID_BOTH_DIR_INFORMATION    BothId;
+        uint8_t                         abPadding[sizeof(FILE_ID_BOTH_DIR_INFORMATION) + RTPATH_MAX * sizeof(wchar_t)];
+    } uBuf;
+
+    /*
+     * We can only use the first option if no additional UNIX attribs are
+     * requested and it isn't a symbolic link.  NT directory object
+     */
+    int rc = VINF_TRY_AGAIN;
+    if (   enmAddAttr != RTFSOBJATTRADD_UNIX
+        && g_pfnNtQueryFullAttributesFile)
+    {
+        InitializeObjectAttributes(&ObjAttr, pNtName, OBJ_CASE_INSENSITIVE, hRootDir, NULL);
+        rcNt = g_pfnNtQueryFullAttributesFile(&ObjAttr, &uBuf.NetOpenInfo);
+        if (NT_SUCCESS(rcNt))
+        {
+            if (!(uBuf.NetOpenInfo.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT))
+            {
+                pObjInfo->cbObject    = uBuf.NetOpenInfo.EndOfFile.QuadPart;
+                pObjInfo->cbAllocated = uBuf.NetOpenInfo.AllocationSize.QuadPart;
+                RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         uBuf.NetOpenInfo.CreationTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        uBuf.NetOpenInfo.LastAccessTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  uBuf.NetOpenInfo.LastWriteTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        uBuf.NetOpenInfo.ChangeTime.QuadPart);
+                pObjInfo->Attr.fMode = rtFsModeFromDos((uBuf.NetOpenInfo.FileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT,
+                                                       pszPath, strlen(pszPath), 0 /*uReparseTag*/, 0);
+                pObjInfo->Attr.enmAdditional = enmAddAttr;
+
+                return rtPathNtQueryInfoFillInDummyData(VINF_SUCCESS, pObjInfo, enmAddAttr);
+            }
+        }
+        else if (   rcNt == STATUS_OBJECT_TYPE_MISMATCH
+                 || rcNt == STATUS_OBJECT_NAME_INVALID
+                 || rcNt == STATUS_INVALID_PARAMETER)
+        {
+            rc = rtPathNtQueryInfoInDirectoryObject(&ObjAttr, pObjInfo, enmAddAttr, fFlags, &uBuf, sizeof(uBuf), rcNt);
+            if (RT_SUCCESS(rc))
+                return rc;
+        }
+        else if (   rcNt != STATUS_ACCESS_DENIED
+                 && rcNt != STATUS_SHARING_VIOLATION)
+            rc = RTErrConvertFromNtStatus(rcNt);
+        else
+            RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+    }
+
+    /*
+     * Try the 2nd option.  We might have to redo this if not following symbolic
+     * links and the reparse point isn't a symbolic link but a mount point or similar.
+     * We want to return information about the mounted root directory if we can, not
+     * the directory in which it was mounted.
+     */
+    if (rc == VINF_TRY_AGAIN)
+    {
+        static int volatile g_fReparsePoints = -1;
+        uint32_t            fOptions         = FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT;
+        int fReparsePoints = g_fReparsePoints;
+        if (fReparsePoints != 0 && !(fFlags & RTPATH_F_FOLLOW_LINK))
+            fOptions |= FILE_OPEN_REPARSE_POINT;
+
+        InitializeObjectAttributes(&ObjAttr, pNtName, OBJ_CASE_INSENSITIVE, hRootDir, NULL);
+        rcNt = NtCreateFile(&hFile,
+                            FILE_READ_ATTRIBUTES | SYNCHRONIZE,
+                            &ObjAttr,
+                            &Ios,
+                            NULL /*pcbFile*/,
+                            FILE_ATTRIBUTE_NORMAL,
+                            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                            FILE_OPEN,
+                            fOptions,
+                            NULL /*pvEaBuffer*/,
+                            0 /*cbEa*/);
+        if (   (   rcNt == STATUS_INVALID_PARAMETER
+                || rcNt == STATUS_INVALID_PARAMETER_9)
+            && fReparsePoints == -1
+            && (fOptions & FILE_OPEN_REPARSE_POINT))
+        {
+            fOptions &= ~FILE_OPEN_REPARSE_POINT;
+            rcNt = NtCreateFile(&hFile,
+                                FILE_READ_ATTRIBUTES | SYNCHRONIZE,
+                                &ObjAttr,
+                                &Ios,
+                                NULL /*pcbFile*/,
+                                FILE_ATTRIBUTE_NORMAL,
+                                FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                FILE_OPEN,
+                                fOptions,
+                                NULL /*pvEaBuffer*/,
+                                0 /*cbEa*/);
+            if (rcNt != STATUS_INVALID_PARAMETER)
+                g_fReparsePoints = fReparsePoints = 0;
+        }
+        if (NT_SUCCESS(rcNt))
+        {
+            /* Query tag information first in order to try re-open non-symlink reparse points. */
+            FILE_ATTRIBUTE_TAG_INFORMATION TagInfo;
+            rcNt = NtQueryInformationFile(hFile, &Ios, &TagInfo, sizeof(TagInfo), FileAttributeTagInformation);
+            if (!NT_SUCCESS(rcNt))
+                TagInfo.FileAttributes = TagInfo.ReparseTag = 0;
+            if (   !(TagInfo.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
+                || TagInfo.ReparseTag == IO_REPARSE_TAG_SYMLINK
+                || (fFlags & RTPATH_F_FOLLOW_LINK))
+            { /* likely */ }
+            else
+            {
+                /* Reparse point that isn't a symbolic link, try follow the reparsing. */
+                HANDLE hFile2;
+                RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+                rcNt = NtCreateFile(&hFile2,
+                                    FILE_READ_ATTRIBUTES | SYNCHRONIZE,
+                                    &ObjAttr,
+                                    &Ios,
+                                    NULL /*pcbFile*/,
+                                    FILE_ATTRIBUTE_NORMAL,
+                                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                    FILE_OPEN,
+                                    FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT,
+                                    NULL /*pvEaBuffer*/,
+                                    0 /*cbEa*/);
+                if (NT_SUCCESS(rcNt))
+                {
+                    NtClose(hFile);
+                    hFile = hFile2;
+                    TagInfo.FileAttributes = TagInfo.ReparseTag = 0;
+                }
+            }
+
+            /*
+             * Get the information we need and convert it.
+             */
+            rc = rtPathNtQueryInfoFromHandle(hFile, &uBuf, sizeof(uBuf), pObjInfo, enmAddAttr, pszPath, TagInfo.ReparseTag);
+            NtClose(hFile);
+            if (RT_SUCCESS(rc))
+                return rc;
+
+            if (RT_FAILURE(rc))
+                rc = VINF_TRY_AGAIN;
+        }
+        else if (   rcNt == STATUS_OBJECT_TYPE_MISMATCH
+                 || rcNt == STATUS_OBJECT_NAME_INVALID
+                 /*|| rcNt == STATUS_INVALID_PARAMETER*/)
+        {
+            rc = rtPathNtQueryInfoInDirectoryObject(&ObjAttr, pObjInfo, enmAddAttr, fFlags, &uBuf, sizeof(uBuf), rcNt);
+            if (RT_SUCCESS(rc))
+                return rc;
+        }
+        else if (   rcNt != STATUS_ACCESS_DENIED
+                 && rcNt != STATUS_SHARING_VIOLATION)
+            rc = RTErrConvertFromNtStatus(rcNt);
+        else
+            RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+    }
+
+    /*
+     * Try the 3rd option if none of the other worked.
+     * If none of the above worked, try open the directory and enumerate
+     * the file we're after.  This
+     */
+    if (rc == VINF_TRY_AGAIN)
+    {
+        /* Split up the name into parent directory path and filename. */
+        UNICODE_STRING NtDirName;
+        UNICODE_STRING NtFilter;
+        ntPathNtSplitName(pNtName, &NtDirName, &NtFilter, false /*fNoParentDirSlash*/);
+
+        /* Try open the directory. */
+        InitializeObjectAttributes(&ObjAttr, &NtDirName, OBJ_CASE_INSENSITIVE, hRootDir, NULL);
+        rcNt = NtCreateFile(&hFile,
+                            FILE_LIST_DIRECTORY | SYNCHRONIZE,
+                            &ObjAttr,
+                            &Ios,
+                            NULL /*pcbFile*/,
+                            FILE_ATTRIBUTE_NORMAL,
+                            FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                            FILE_OPEN,
+                            FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT,
+                            NULL /*pvEaBuffer*/,
+                            0 /*cbEa*/);
+        if (NT_SUCCESS(rcNt))
+        {
+            FILE_INFORMATION_CLASS enmInfoClass;
+            if (RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion) > RT_MAKE_U64(0,5) /* > W2K */)
+                enmInfoClass = FileIdBothDirectoryInformation; /* Introduced in XP, from I can tell. */
+            else
+                enmInfoClass = FileBothDirectoryInformation;
+            rcNt = NtQueryDirectoryFile(hFile,
+                                        NULL /* Event */,
+                                        NULL /* ApcRoutine */,
+                                        NULL /* ApcContext */,
+                                        &Ios,
+                                        &uBuf,
+                                        RT_MIN(sizeof(uBuf), 0xfff0),
+                                        enmInfoClass,
+                                        TRUE /*ReturnSingleEntry */,
+                                        &NtFilter,
+                                        FALSE /*RestartScan */);
+            if (NT_SUCCESS(rcNt))
+            {
+                pObjInfo->cbObject    = uBuf.Both.EndOfFile.QuadPart;
+                pObjInfo->cbAllocated = uBuf.Both.AllocationSize.QuadPart;
+
+                RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         uBuf.Both.CreationTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        uBuf.Both.LastAccessTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  uBuf.Both.LastWriteTime.QuadPart);
+                RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        uBuf.Both.ChangeTime.QuadPart);
+
+                pObjInfo->Attr.fMode  = rtFsModeFromDos((uBuf.Both.FileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT,
+                                                        pszPath, strlen(pszPath), uBuf.Both.EaSize, 0);
+
+                pObjInfo->Attr.enmAdditional = enmAddAttr;
+                if (enmAddAttr == RTFSOBJATTRADD_UNIX)
+                {
+                    pObjInfo->Attr.u.Unix.uid             = ~0U;
+                    pObjInfo->Attr.u.Unix.gid             = ~0U;
+                    pObjInfo->Attr.u.Unix.cHardlinks      = 1;
+                    pObjInfo->Attr.u.Unix.INodeIdDevice   = 0; /* below */
+                    pObjInfo->Attr.u.Unix.INodeId         = enmInfoClass == FileIdBothDirectoryInformation
+                                                          ? uBuf.BothId.FileId.QuadPart : 0;
+                    pObjInfo->Attr.u.Unix.fFlags          = 0;
+                    pObjInfo->Attr.u.Unix.GenerationId    = 0;
+                    pObjInfo->Attr.u.Unix.Device          = 0;
+
+                    /* Get the serial number. */
+                    rcNt = NtQueryVolumeInformationFile(hFile, &Ios, &uBuf, RT_MIN(sizeof(uBuf), _2K),
+                                                        FileFsVolumeInformation);
+                    if (NT_SUCCESS(rcNt))
+                        pObjInfo->Attr.u.Unix.INodeIdDevice = uBuf.VolInfo.VolumeSerialNumber;
+                }
+
+                rc = rtPathNtQueryInfoFillInDummyData(VINF_SUCCESS, pObjInfo, enmAddAttr);
+            }
+            else
+                rc = RTErrConvertFromNtStatus(rcNt);
+
+            NtClose(hFile);
+        }
+        /*
+         * Quite possibly a object directory.
+         */
+        else if (   rcNt == STATUS_OBJECT_NAME_INVALID  /* with trailing slash */
+                 || rcNt == STATUS_OBJECT_TYPE_MISMATCH /* without trailing slash */ )
+        {
+            InitializeObjectAttributes(&ObjAttr, pNtName, OBJ_CASE_INSENSITIVE, hRootDir, NULL);
+            rc = rtPathNtQueryInfoInDirectoryObject(&ObjAttr, pObjInfo, enmAddAttr, fFlags, &uBuf, sizeof(uBuf), rcNt);
+            if (RT_FAILURE(rc))
+                rc = RTErrConvertFromNtStatus(rcNt);
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+    }
+
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathQueryInfoEx(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pObjInfo, VERR_INVALID_POINTER);
+    AssertMsgReturn(    enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING
+                    &&  enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                    ("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs),
+                    VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+
+    /*
+     * Convert the input path and call common worker.
+     */
+    HANDLE         hRootDir;
+    UNICODE_STRING NtName;
+    int rc = RTNtPathFromWinUtf8(&NtName, &hRootDir, pszPath);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPathNtQueryInfoWorker(hRootDir, &NtName, pObjInfo, enmAdditionalAttribs, fFlags, pszPath);
+        RTNtPathFree(&NtName, &hRootDir);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathQueryInfo(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    return RTPathQueryInfoEx(pszPath, pObjInfo, enmAdditionalAttribs, RTPATH_F_ON_LINK);
+}
+
diff --git a/src/VBox/Runtime/r3/nt/RTPathSetMode-r3-nt.cpp b/src/VBox/Runtime/r3/nt/RTPathSetMode-r3-nt.cpp
new file mode 100644
index 00000000..d6fb0444
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/RTPathSetMode-r3-nt.cpp
@@ -0,0 +1,98 @@
+/* $Id: RTPathSetMode-r3-nt.cpp $ */
+/** @file
+ * IPRT - RTPathSetMode, Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include "internal-r3-nt.h"
+
+#include <iprt/path.h>
+#include <iprt/err.h>
+
+#include "internal/fs.h"
+
+
+
+RTDECL(int) RTPathSetMode(const char *pszPath, RTFMODE fMode)
+{
+    fMode = rtFsModeNormalize(fMode, pszPath, 0, 0);
+    AssertReturn(rtFsModeIsValidPermissions(fMode), VERR_INVALID_FMODE);
+
+    /*
+     * Convert and normalize the path.
+     */
+    UNICODE_STRING NtName;
+    HANDLE         hRootDir;
+    int rc = RTNtPathFromWinUtf8(&NtName, &hRootDir, pszPath);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE              hPath   = RTNT_INVALID_HANDLE_VALUE;
+        IO_STATUS_BLOCK     Ios     = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        OBJECT_ATTRIBUTES   ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, &NtName, 0 /*fAttrib*/, hRootDir, NULL);
+
+        ULONG fOpenOptions = FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_REPARSE_POINT;
+        //if (fFlags & RTPATH_F_ON_LINK)
+        //    fOpenOptions |= FILE_OPEN_REPARSE_POINT;
+        NTSTATUS rcNt = NtCreateFile(&hPath,
+                                     FILE_WRITE_ATTRIBUTES | SYNCHRONIZE,
+                                     &ObjAttr,
+                                     &Ios,
+                                     NULL /*AllocationSize*/,
+                                     FILE_ATTRIBUTE_NORMAL,
+                                     FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                     FILE_OPEN,
+                                     fOpenOptions,
+                                     NULL /*EaBuffer*/,
+                                     0 /*EaLength*/);
+        if (NT_SUCCESS(rcNt))
+        {
+            rc = rtNtFileSetModeWorker(hPath, fMode);
+
+            rcNt = NtClose(hPath);
+            if (!NT_SUCCESS(rcNt) && RT_SUCCESS(rc))
+                rc = RTErrConvertFromNtStatus(rcNt);
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+
+        RTNtPathFree(&NtName, &hRootDir);
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/nt/RTProcQueryParent-r3-nt.cpp b/src/VBox/Runtime/r3/nt/RTProcQueryParent-r3-nt.cpp
new file mode 100644
index 00000000..650131d1
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/RTProcQueryParent-r3-nt.cpp
@@ -0,0 +1,103 @@
+/* $Id: RTProcQueryParent-r3-nt.cpp $ */
+/** @file
+ * IPRT - Process, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/nt/nt.h>
+
+#include <iprt/process.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+
+
+RTR3DECL(int) RTProcQueryParent(RTPROCESS hProcess, PRTPROCESS phParent)
+{
+    NTSTATUS    rcNt;
+    HANDLE      hClose = RTNT_INVALID_HANDLE_VALUE;
+    HANDLE      hNtProc;
+
+    /*
+     * Open the process.  We take a shortcut if it's the current process.
+     */
+    if (hProcess == RTProcSelf())
+        hNtProc = NtCurrentProcess();
+    else
+    {
+        CLIENT_ID ClientId;
+        ClientId.UniqueProcess = (HANDLE)(uintptr_t)hProcess;
+        ClientId.UniqueThread  = NULL;
+
+        OBJECT_ATTRIBUTES ObjAttrs;
+        InitializeObjectAttributes(&ObjAttrs, NULL, OBJ_CASE_INSENSITIVE, NULL, NULL);
+
+        rcNt = NtOpenProcess(&hClose, PROCESS_QUERY_LIMITED_INFORMATION, &ObjAttrs, &ClientId);
+        if (!NT_SUCCESS(rcNt))
+            rcNt = NtOpenProcess(&hClose, PROCESS_QUERY_INFORMATION, &ObjAttrs, &ClientId);
+        if (!NT_SUCCESS(rcNt))
+            return RTErrConvertFromNtStatus(rcNt);
+        hNtProc = hClose;
+    }
+
+    /*
+     * Query the information.
+     */
+    int rc;
+    PROCESS_BASIC_INFORMATION BasicInfo;
+    ULONG cbIgn;
+    rcNt = NtQueryInformationProcess(hNtProc, ProcessBasicInformation, &BasicInfo, sizeof(BasicInfo), &cbIgn);
+    if (NT_SUCCESS(rcNt))
+    {
+        *phParent = BasicInfo.InheritedFromUniqueProcessId;
+        rc = VINF_SUCCESS;
+    }
+    else
+        rc = RTErrConvertFromNtStatus(rcNt);
+
+    /*
+     * Clean up.
+     */
+    if (hClose != RTNT_INVALID_HANDLE_VALUE)
+        NtClose(hClose);
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/nt/direnum-r3-nt.cpp b/src/VBox/Runtime/r3/nt/direnum-r3-nt.cpp
new file mode 100644
index 00000000..0325e842
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/direnum-r3-nt.cpp
@@ -0,0 +1,1011 @@
+/* $Id: direnum-r3-nt.cpp $ */
+/** @file
+ * IPRT - Directory Enumeration, Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include "internal-r3-nt.h"
+
+#include <iprt/dir.h>
+#include <iprt/path.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include <iprt/utf16.h>
+#include "internal/fs.h"
+#include "internal/dir.h"
+#include "internal/path.h"
+#include "../win/internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Whether to return a single record (TRUE) or multiple (FALSE). */
+#define RTDIR_NT_SINGLE_RECORD  FALSE
+
+/** Go hard on record chaining (has slight performance impact). */
+#ifdef RT_STRICT
+# define RTDIR_NT_STRICT
+#endif
+
+
+/* ASSUMES FileID comes after ShortName and the structs are identical up to that point. */
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, NextEntryOffset, FILE_ID_BOTH_DIR_INFORMATION, NextEntryOffset);
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileIndex      , FILE_ID_BOTH_DIR_INFORMATION, FileIndex      );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, CreationTime   , FILE_ID_BOTH_DIR_INFORMATION, CreationTime   );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, LastAccessTime , FILE_ID_BOTH_DIR_INFORMATION, LastAccessTime );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, LastWriteTime  , FILE_ID_BOTH_DIR_INFORMATION, LastWriteTime  );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ChangeTime     , FILE_ID_BOTH_DIR_INFORMATION, ChangeTime     );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, EndOfFile      , FILE_ID_BOTH_DIR_INFORMATION, EndOfFile      );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, AllocationSize , FILE_ID_BOTH_DIR_INFORMATION, AllocationSize );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileAttributes , FILE_ID_BOTH_DIR_INFORMATION, FileAttributes );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, FileNameLength , FILE_ID_BOTH_DIR_INFORMATION, FileNameLength );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, EaSize         , FILE_ID_BOTH_DIR_INFORMATION, EaSize         );
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ShortNameLength, FILE_ID_BOTH_DIR_INFORMATION, ShortNameLength);
+AssertCompileMembersSameSizeAndOffset(FILE_BOTH_DIR_INFORMATION, ShortName      , FILE_ID_BOTH_DIR_INFORMATION, ShortName      );
+
+
+
+size_t rtDirNativeGetStructSize(const char *pszPath)
+{
+    NOREF(pszPath);
+    return sizeof(RTDIRINTERNAL);
+}
+
+
+int rtDirNativeOpen(PRTDIRINTERNAL pDir, uintptr_t hRelativeDir, void *pvNativeRelative)
+{
+    /*
+     * Convert the filter to UTF-16.
+     */
+    int rc;
+    pDir->pNtFilterStr = NULL;
+    if (   pDir->cchFilter > 0
+        && pDir->enmFilter == RTDIRFILTER_WINNT)
+    {
+        PRTUTF16 pwszTmp;
+        rc = RTStrToUtf16(pDir->pszFilter, &pwszTmp);
+        if (RT_FAILURE(rc))
+            return rc;
+        pDir->NtFilterStr.Buffer = pwszTmp;
+        pDir->NtFilterStr.Length = pDir->NtFilterStr.MaximumLength = (uint16_t)(RTUtf16Len(pwszTmp) * sizeof(RTUTF16));
+        pDir->pNtFilterStr = &pDir->NtFilterStr;
+    }
+
+    /*
+     * Try open the directory
+     */
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    bool fObjDir = false;
+#endif
+    if (hRelativeDir != ~(uintptr_t)0 && pvNativeRelative == NULL)
+    {
+        /* Caller already opened it, easy! */
+        pDir->hDir = (HANDLE)hRelativeDir;
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        /*
+         * If we have to check for reparse points, this gets complicated!
+         */
+        static int volatile g_fReparsePoints = -1;
+        uint32_t            fOptions         = FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT;
+        int fReparsePoints = g_fReparsePoints;
+        if (   fReparsePoints != 0
+            && (pDir->fFlags & RTDIR_F_NO_FOLLOW)
+            && !pDir->fDirSlash)
+            fOptions |= FILE_OPEN_REPARSE_POINT;
+
+        ACCESS_MASK fDesiredAccess = FILE_LIST_DIRECTORY | FILE_READ_ATTRIBUTES | FILE_TRAVERSE | SYNCHRONIZE;
+        for (;;)
+        {
+            if (pvNativeRelative == NULL)
+                rc = RTNtPathOpenDir(pDir->pszPath,
+                                     fDesiredAccess,
+                                     FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                     fOptions,
+                                     OBJ_CASE_INSENSITIVE,
+                                     &pDir->hDir,
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+                                     &fObjDir
+#else
+                                     NULL
+#endif
+                                     );
+            else
+                rc = RTNtPathOpenDirEx((HANDLE)hRelativeDir,
+                                       (struct _UNICODE_STRING *)pvNativeRelative,
+                                       fDesiredAccess,
+                                       FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                       fOptions,
+                                       OBJ_CASE_INSENSITIVE,
+                                       &pDir->hDir,
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+                                       &fObjDir
+#else
+                                       NULL
+#endif
+                                       );
+            if (   rc == VERR_ACCESS_DENIED             /* Seen with c:\windows\system32\com\dmp on w7 & w10 (admin mode). */
+                && (fDesiredAccess & FILE_TRAVERSE))
+            {
+                fDesiredAccess &= ~FILE_TRAVERSE;
+                continue;
+            }
+            if (   !(fOptions & FILE_OPEN_REPARSE_POINT)
+                || (rc != VINF_SUCCESS && rc != VERR_INVALID_PARAMETER) )
+                break;
+            if (rc == VINF_SUCCESS)
+            {
+                if (fReparsePoints == -1)
+                    g_fReparsePoints = 1;
+
+                /*
+                 * We now need to check if we opened a symbolic directory link.
+                 * (These can be enumerated, but contains only '.' and '..'.)
+                 */
+                FILE_ATTRIBUTE_TAG_INFORMATION  TagInfo = { 0, 0 };
+                IO_STATUS_BLOCK                 Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+                NTSTATUS rcNt = NtQueryInformationFile(pDir->hDir, &Ios, &TagInfo, sizeof(TagInfo), FileAttributeTagInformation);
+                AssertMsg(NT_SUCCESS(rcNt), ("%#x\n", rcNt));
+                if (!NT_SUCCESS(rcNt))
+                    TagInfo.FileAttributes = TagInfo.ReparseTag = 0;
+                if (!(TagInfo.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT))
+                    break;
+
+                NtClose(pDir->hDir);
+                pDir->hDir = RTNT_INVALID_HANDLE_VALUE;
+
+                if (TagInfo.ReparseTag == IO_REPARSE_TAG_SYMLINK)
+                {
+                    rc = VERR_IS_A_SYMLINK;
+                    break;
+                }
+
+                /* Reparse point that isn't a symbolic link, try follow the reparsing. */
+            }
+            else if (fReparsePoints == -1)
+                g_fReparsePoints = fReparsePoints = 0;
+            fOptions &= ~FILE_OPEN_REPARSE_POINT;
+        }
+
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Init data.
+         */
+        pDir->fDataUnread = false; /* spelling it out */
+        pDir->uDirDev     = 0;
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+        if (fObjDir)
+            pDir->enmInfoClass = FileMaximumInformation; /* object directory. */
+#endif
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirClose(RTDIR hDir)
+{
+    PRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate input.
+     */
+    if (!pDir)
+        return VERR_INVALID_PARAMETER;
+    if (pDir->u32Magic != RTDIR_MAGIC)
+    {
+        AssertMsgFailed(("Invalid pDir=%p\n", pDir));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Close the handle.
+     */
+    pDir->u32Magic = ~RTDIR_MAGIC;
+    if (pDir->hDir != RTNT_INVALID_HANDLE_VALUE)
+    {
+        int rc = RTNtPathClose(pDir->hDir);
+        AssertRC(rc);
+        pDir->hDir = RTNT_INVALID_HANDLE_VALUE;
+    }
+    RTStrFree(pDir->pszName);
+    pDir->pszName = NULL;
+    RTUtf16Free(pDir->NtFilterStr.Buffer);
+    pDir->NtFilterStr.Buffer = NULL;
+    RTMemFree(pDir->pabBuffer);
+    pDir->pabBuffer = NULL;
+    RTMemFree(pDir);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks the validity of the current record.
+ *
+ * @returns IPRT status code
+ * @param   pThis       The directory instance data.
+ */
+static int rtDirNtCheckRecord(PRTDIRINTERNAL pThis)
+{
+#if defined(RTDIR_NT_STRICT) || defined(RT_ARCH_X86)
+# ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    if (pThis->enmInfoClass != FileMaximumInformation)
+# endif
+    {
+        uintptr_t uEndAddr;
+        if (pThis->enmInfoClass == FileIdBothDirectoryInformation)
+            uEndAddr = (uintptr_t)&pThis->uCurData.pBothId->FileName[0];
+        else
+            uEndAddr = (uintptr_t)&pThis->uCurData.pBoth->FileName[0];
+
+# ifdef RT_ARCH_X86
+        /* Workaround for NT 3.1 bug where FAT returns a too short buffer length.
+           Including all NT 3.x versions in case it bug was fixed till NT 4. */
+        uintptr_t const uEndBuffer = (uintptr_t)&pThis->pabBuffer[pThis->cbBuffer];
+        if (   uEndAddr < uEndBuffer
+            && uEndAddr + pThis->uCurData.pBoth->FileNameLength <= uEndBuffer)
+        { /* likely */ }
+        else if (   (   g_enmWinVer == kRTWinOSType_NT310
+                     || g_enmWinVer == kRTWinOSType_NT350 // not sure when it was fixed...
+                     || g_enmWinVer == kRTWinOSType_NT351)
+                 && pThis->enmInfoClass == FileBothDirectoryInformation)
+        {
+            size_t cbLeft = (uintptr_t)&pThis->pabBuffer[pThis->cbBufferAlloc] - (uintptr_t)pThis->uCurData.pBoth;
+            if (   cbLeft >= RT_UOFFSETOF(FILE_BOTH_DIR_INFORMATION, FileName)
+                && pThis->uCurData.pBoth->FileNameLength > 0
+                && cbLeft >= RT_UOFFSETOF(FILE_BOTH_DIR_INFORMATION, FileName) + pThis->uCurData.pBoth->FileNameLength)
+            {
+                pThis->cbBuffer = ((uintptr_t)&pThis->uCurData.pBoth->FileName[0] + pThis->uCurData.pBoth->FileNameLength)
+                                - (uintptr_t)&pThis->pabBuffer[0];
+            }
+        }
+# endif
+
+# ifdef RTDIR_NT_STRICT
+        AssertReturn(uEndAddr < (uintptr_t)&pThis->pabBuffer[pThis->cbBuffer], VERR_IO_GEN_FAILURE);
+        AssertReturn(pThis->uCurData.pBoth->FileNameLength < _64K, VERR_FILENAME_TOO_LONG);
+        AssertReturn((pThis->uCurData.pBoth->FileNameLength & 1) == 0, VERR_IO_GEN_FAILURE);
+
+        uEndAddr += pThis->uCurData.pBoth->FileNameLength;
+        AssertReturn(uEndAddr <= (uintptr_t)&pThis->pabBuffer[pThis->cbBuffer], VERR_IO_GEN_FAILURE);
+
+        AssertReturn((unsigned)pThis->uCurData.pBoth->ShortNameLength <= sizeof(pThis->uCurData.pBoth->ShortName),
+                     VERR_IO_GEN_FAILURE);
+# endif
+    }
+#else
+    RT_NOREF_PV(pThis);
+#endif
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Advances the buffer pointer.
+ *
+ * @param   pThis       The directory instance data.
+ */
+static int rtDirNtAdvanceBuffer(PRTDIRINTERNAL pThis)
+{
+    int rc;
+
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    if (pThis->enmInfoClass == FileMaximumInformation)
+    {
+        pThis->uCurData.pObjDir++;
+        pThis->fDataUnread = pThis->uCurData.pObjDir->Name.Length != 0;
+        return VINF_SUCCESS;
+    }
+#endif
+
+    pThis->fDataUnread = false;
+
+    uint32_t const offNext = pThis->uCurData.pBoth->NextEntryOffset;
+    if (offNext == 0)
+        return VINF_SUCCESS;
+
+#ifdef RTDIR_NT_STRICT
+    /* Make sure the next-record offset is beyond the current record. */
+    size_t cbRec;
+    if (pThis->enmInfoClass == FileIdBothDirectoryInformation)
+        cbRec = RT_UOFFSETOF(FILE_ID_BOTH_DIR_INFORMATION, FileName);
+    else
+        cbRec = RT_UOFFSETOF(FILE_BOTH_DIR_INFORMATION, FileName);
+    cbRec += pThis->uCurData.pBoth->FileNameLength;
+    AssertReturn(offNext >= cbRec, VERR_IO_GEN_FAILURE);
+#endif
+    pThis->uCurData.u += offNext;
+
+    rc = rtDirNtCheckRecord(pThis);
+    pThis->fDataUnread = RT_SUCCESS(rc);
+    return rc;
+}
+
+
+/**
+ * Fetches more data from the file system.
+ *
+ * @returns IPRT status code
+ * @param   pThis       The directory instance data.
+ */
+static int rtDirNtFetchMore(PRTDIRINTERNAL pThis)
+{
+    Assert(!pThis->fDataUnread);
+
+    /*
+     * Allocate the buffer the first time around.
+     * We do this in lazy fashion as some users of RTDirOpen will not actually
+     * list any files, just open it for various reasons.
+     *
+     * We also reduce the buffer size for networked devices as the windows 7-8.1,
+     * server 2012, ++ CIFS servers or/and IFSes screws up buffers larger than 64KB.
+     * There is an alternative hack below, btw.  We'll leave both in for now.
+     */
+    bool fFirst = false;
+    if (!pThis->pabBuffer)
+    {
+        pThis->cbBufferAlloc = _256K;
+        if (true) /** @todo skip for known local devices, like the boot device? */
+        {
+            IO_STATUS_BLOCK Ios2 = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+            FILE_FS_DEVICE_INFORMATION Info = { 0, 0 };
+            NTSTATUS rcNt2 = NtQueryVolumeInformationFile(pThis->hDir, &Ios2, &Info, sizeof(Info), FileFsDeviceInformation);
+            if (   !NT_SUCCESS(rcNt2)
+                || (Info.Characteristics & FILE_REMOTE_DEVICE)
+                || Info.DeviceType == FILE_DEVICE_NETWORK
+                || Info.DeviceType == FILE_DEVICE_NETWORK_FILE_SYSTEM
+                || Info.DeviceType == FILE_DEVICE_NETWORK_REDIRECTOR
+                || Info.DeviceType == FILE_DEVICE_SMB)
+                pThis->cbBufferAlloc = _64K;
+        }
+
+        fFirst = false;
+        pThis->pabBuffer = (uint8_t *)RTMemAlloc(pThis->cbBufferAlloc);
+        if (!pThis->pabBuffer)
+        {
+            do
+            {
+                pThis->cbBufferAlloc /= 4;
+                pThis->pabBuffer = (uint8_t *)RTMemAlloc(pThis->cbBufferAlloc);
+            } while (pThis->pabBuffer == NULL && pThis->cbBufferAlloc > _4K);
+            if (!pThis->pabBuffer)
+                return VERR_NO_MEMORY;
+        }
+
+        /*
+         * Also try determining the device number.
+         */
+        PFILE_FS_VOLUME_INFORMATION pVolInfo = (PFILE_FS_VOLUME_INFORMATION)pThis->pabBuffer;
+        pVolInfo->VolumeSerialNumber = 0;
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NTSTATUS rcNt = NtQueryVolumeInformationFile(pThis->hDir, &Ios,
+                                                     pVolInfo, RT_MIN(_2K, pThis->cbBufferAlloc),
+                                                     FileFsVolumeInformation);
+        if (NT_SUCCESS(rcNt) && NT_SUCCESS(Ios.Status))
+            pThis->uDirDev = pVolInfo->VolumeSerialNumber;
+        else
+            pThis->uDirDev = 0;
+        AssertCompile(sizeof(pThis->uDirDev) == sizeof(pVolInfo->VolumeSerialNumber));
+        /** @todo Grow RTDEV to 64-bit and add low dword of VolumeCreationTime to the top of uDirDev. */
+    }
+
+    /*
+     * Read more.
+     */
+    NTSTATUS rcNt;
+    IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    if (pThis->enmInfoClass != (FILE_INFORMATION_CLASS)0)
+    {
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+        if (pThis->enmInfoClass == FileMaximumInformation)
+        {
+            Ios.Information = 0;
+            Ios.Status = rcNt = NtQueryDirectoryObject(pThis->hDir,
+                                                       pThis->pabBuffer,
+                                                       pThis->cbBufferAlloc,
+                                                       RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
+                                                       pThis->fRestartScan,
+                                                       &pThis->uObjDirCtx,
+                                                       (PULONG)&Ios.Information);
+        }
+        else
+#endif
+            rcNt = NtQueryDirectoryFile(pThis->hDir,
+                                        NULL /* Event */,
+                                        NULL /* ApcRoutine */,
+                                        NULL /* ApcContext */,
+                                        &Ios,
+                                        pThis->pabBuffer,
+                                        pThis->cbBufferAlloc,
+                                        pThis->enmInfoClass,
+                                        RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
+                                        pThis->pNtFilterStr,
+                                        pThis->fRestartScan);
+    }
+    else
+    {
+        /*
+         * The first time around we have to figure which info class we can use
+         * as well as the right buffer size.  We prefer an info class which
+         * gives us file IDs (Vista+ IIRC) and we prefer large buffers (for long
+         * ReFS file names and such), but we'll settle for whatever works...
+         *
+         * The windows 7 thru 8.1 CIFS servers have been observed to have
+         * trouble with large buffers, but weirdly only when listing large
+         * directories.  Seems 0x10000 is the max.  (Samba does not exhibit
+         * these problems, of course.)
+         *
+         * This complicates things.  The buffer size issues causes an
+         * STATUS_INVALID_PARAMETER error.  Now, you would expect the lack of
+         * FileIdBothDirectoryInformation support to return
+         * STATUS_INVALID_INFO_CLASS, but I'm not entirely sure if we can 100%
+         * depend on third IFSs to get that right.  Nor, am I entirely confident
+         * that we can depend on them to check the class before the buffer size.
+         *
+         * Thus the mess.
+         */
+        if (RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion) > RT_MAKE_U64(0,5) /* > W2K */)
+            pThis->enmInfoClass = FileIdBothDirectoryInformation; /* Introduced in XP, from I can tell. */
+        else
+            pThis->enmInfoClass = FileBothDirectoryInformation;
+        rcNt = NtQueryDirectoryFile(pThis->hDir,
+                                    NULL /* Event */,
+                                    NULL /* ApcRoutine */,
+                                    NULL /* ApcContext */,
+                                    &Ios,
+                                    pThis->pabBuffer,
+                                    pThis->cbBufferAlloc,
+                                    pThis->enmInfoClass,
+                                    RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
+                                    pThis->pNtFilterStr,
+                                    pThis->fRestartScan);
+        if (NT_SUCCESS(rcNt))
+        { /* likely */ }
+        else
+        {
+            bool fRestartScan = pThis->fRestartScan;
+            for (unsigned iRetry = 0; iRetry < 2; iRetry++)
+            {
+                if (   rcNt == STATUS_INVALID_INFO_CLASS
+                    || rcNt == STATUS_INVALID_PARAMETER_8
+                    || iRetry != 0)
+                    pThis->enmInfoClass = FileBothDirectoryInformation;
+
+                uint32_t cbBuffer = pThis->cbBufferAlloc;
+                if (   rcNt == STATUS_INVALID_PARAMETER
+                    || rcNt == STATUS_INVALID_PARAMETER_7
+                    || rcNt == STATUS_INVALID_NETWORK_RESPONSE
+                    || iRetry != 0)
+                {
+                    cbBuffer = RT_MIN(cbBuffer / 2, _64K);
+                    fRestartScan = true;
+                }
+
+                for (;;)
+                {
+                    rcNt = NtQueryDirectoryFile(pThis->hDir,
+                                                NULL /* Event */,
+                                                NULL /* ApcRoutine */,
+                                                NULL /* ApcContext */,
+                                                &Ios,
+                                                pThis->pabBuffer,
+                                                cbBuffer,
+                                                pThis->enmInfoClass,
+                                                RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
+                                                pThis->pNtFilterStr,
+                                                fRestartScan);
+                    if (   NT_SUCCESS(rcNt)
+                        || cbBuffer == pThis->cbBufferAlloc
+                        || cbBuffer <= sizeof(*pThis->uCurData.pBothId) + sizeof(WCHAR) * 260)
+                        break;
+
+                    /* Reduce the buffer size agressivly and try again.  We fall back to
+                       FindFirstFile values for the final lap.  This means we'll do 4 rounds
+                       with the current initial buffer size (64KB, 8KB, 1KB, 0x278/0x268). */
+                    cbBuffer /= 8;
+                    if (cbBuffer < 1024)
+                        cbBuffer = pThis->enmInfoClass == FileIdBothDirectoryInformation
+                                 ? sizeof(*pThis->uCurData.pBothId) + sizeof(WCHAR) * 260
+                                 : sizeof(*pThis->uCurData.pBoth)   + sizeof(WCHAR) * 260;
+                }
+                if (NT_SUCCESS(rcNt))
+                {
+                    pThis->cbBufferAlloc = cbBuffer;
+                    break;
+                }
+            }
+        }
+    }
+    if (!NT_SUCCESS(rcNt))
+    {
+        /* Note! VBoxSVR and CIFS file systems both ends up with STATUS_NO_SUCH_FILE here instead of STATUS_NO_MORE_FILES. */
+        if (rcNt == STATUS_NO_MORE_FILES || rcNt == STATUS_NO_MORE_ENTRIES || rcNt == STATUS_NO_SUCH_FILE)
+            return VERR_NO_MORE_FILES;
+        return RTErrConvertFromNtStatus(rcNt);
+    }
+    pThis->fRestartScan = false;
+    AssertMsg(  Ios.Information
+              > (pThis->enmInfoClass == FileMaximumInformation ? sizeof(*pThis->uCurData.pObjDir) : sizeof(*pThis->uCurData.pBoth)),
+              ("Ios.Information=%#x\n", Ios.Information));
+
+    /*
+     * Set up the data members.
+     */
+    pThis->uCurData.u  = (uintptr_t)pThis->pabBuffer;
+    pThis->cbBuffer    = Ios.Information;
+
+    int rc = rtDirNtCheckRecord(pThis);
+    pThis->fDataUnread = RT_SUCCESS(rc);
+
+    return rc;
+}
+
+
+/**
+ * Converts the name from UTF-16 to UTF-8.
+ *
+ * Fortunately, the names are relative to the directory, so we won't have to do
+ * any sweaty path style coversion. :-)
+ *
+ * @returns IPRT status code
+ * @param   pThis       The directory instance data.
+ * @param   cbName      The file name length in bytes.
+ * @param   pwsName     The file name, not terminated.
+ */
+static int rtDirNtConvertName(PRTDIRINTERNAL pThis, uint32_t cbName, PCRTUTF16 pwsName)
+{
+    int rc = RTUtf16ToUtf8Ex(pwsName, cbName / 2, &pThis->pszName, pThis->cbNameAlloc, &pThis->cchName);
+    if (RT_SUCCESS(rc))
+    {
+        if (!pThis->cbNameAlloc)
+            pThis->cbNameAlloc = pThis->cchName + 1;
+    }
+    else if (rc == VERR_BUFFER_OVERFLOW)
+    {
+        RTStrFree(pThis->pszName);
+        pThis->pszName = NULL;
+        pThis->cbNameAlloc = 0;
+
+        rc = RTUtf16ToUtf8Ex(pwsName, cbName / 2, &pThis->pszName, pThis->cbNameAlloc, &pThis->cchName);
+        if (RT_SUCCESS(rc))
+            pThis->cbNameAlloc = pThis->cchName + 1;
+    }
+    Assert(RT_SUCCESS(rc) ? pThis->pszName != NULL : pThis->pszName == NULL);
+    return rc;
+}
+
+
+/**
+ * Converts the name of the current record.
+ *
+ * @returns IPRT status code.
+ * @param   pThis       The directory instance data.
+ */
+static int rtDirNtConvertCurName(PRTDIRINTERNAL pThis)
+{
+    switch (pThis->enmInfoClass)
+    {
+        case FileIdBothDirectoryInformation:
+            return rtDirNtConvertName(pThis, pThis->uCurData.pBothId->FileNameLength, pThis->uCurData.pBothId->FileName);
+        case FileBothDirectoryInformation:
+            return rtDirNtConvertName(pThis, pThis->uCurData.pBoth->FileNameLength, pThis->uCurData.pBoth->FileName);
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+        case FileMaximumInformation:
+            return rtDirNtConvertName(pThis, pThis->uCurData.pObjDir->Name.Length, pThis->uCurData.pObjDir->Name.Buffer);
+#endif
+
+        default:
+            AssertFailedReturn(VERR_INTERNAL_ERROR_3);
+    }
+}
+
+
+RTDECL(int) RTDirRead(RTDIR hDir, PRTDIRENTRY pDirEntry, size_t *pcbDirEntry)
+{
+    PRTDIRINTERNAL pDir = hDir;
+    int rc;
+
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pDir, VERR_INVALID_POINTER);
+    AssertReturn(pDir->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pDirEntry, VERR_INVALID_POINTER);
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        cbDirEntry = *pcbDirEntry;
+        AssertMsgReturn(cbDirEntry >= RT_UOFFSETOF(RTDIRENTRY, szName[2]),
+                        ("Invalid *pcbDirEntry=%zu (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRY, szName[2])),
+                        VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Fetch data?
+     */
+    if (!pDir->fDataUnread)
+    {
+        rc = rtDirNtFetchMore(pDir);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+
+    /*
+     * Convert the filename to UTF-8.
+     */
+    rc = rtDirNtConvertCurName(pDir);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Check if we've got enough space to return the data.
+     */
+    const char  *pszName    = pDir->pszName;
+    const size_t cchName    = pDir->cchName;
+    const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRY, szName[1]) + cchName;
+    if (pcbDirEntry)
+        *pcbDirEntry = cbRequired;
+    if (cbRequired > cbDirEntry)
+        return VERR_BUFFER_OVERFLOW;
+
+    /*
+     * Setup the returned data.
+     */
+    pDirEntry->cbName = (uint16_t)cchName; Assert(pDirEntry->cbName == cchName);
+    memcpy(pDirEntry->szName, pszName, cchName + 1);
+
+    pDirEntry->INodeId = pDir->enmInfoClass == FileIdBothDirectoryInformation
+                       ? pDir->uCurData.pBothId->FileId.QuadPart : 0;
+
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    if (pDir->enmInfoClass != FileMaximumInformation)
+#endif
+    {
+        switch (   pDir->uCurData.pBoth->FileAttributes
+                & (FILE_ATTRIBUTE_REPARSE_POINT | FILE_ATTRIBUTE_REPARSE_POINT | FILE_ATTRIBUTE_DIRECTORY))
+        {
+            default:
+                AssertFailed();
+            case 0:
+                pDirEntry->enmType = RTDIRENTRYTYPE_FILE;
+                break;
+
+            case FILE_ATTRIBUTE_DIRECTORY:
+                pDirEntry->enmType = RTDIRENTRYTYPE_DIRECTORY;
+                break;
+
+            case FILE_ATTRIBUTE_REPARSE_POINT:
+            case FILE_ATTRIBUTE_REPARSE_POINT | FILE_ATTRIBUTE_DIRECTORY:
+                /* EaSize is here reused for returning the repharse tag value. */
+                if (pDir->uCurData.pBoth->EaSize == IO_REPARSE_TAG_SYMLINK)
+                    pDirEntry->enmType = RTDIRENTRYTYPE_SYMLINK;
+                break;
+        }
+    }
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    else
+    {
+        pDirEntry->enmType = RTDIRENTRYTYPE_UNKNOWN;
+        if (rtNtCompWideStrAndAscii(pDir->uCurData.pObjDir->TypeName.Buffer, pDir->uCurData.pObjDir->TypeName.Length,
+                                    RT_STR_TUPLE("Directory")))
+            pDirEntry->enmType = RTDIRENTRYTYPE_DIRECTORY;
+        else if (rtNtCompWideStrAndAscii(pDir->uCurData.pObjDir->TypeName.Buffer, pDir->uCurData.pObjDir->TypeName.Length,
+                                         RT_STR_TUPLE("SymbolicLink")))
+            pDirEntry->enmType = RTDIRENTRYTYPE_SYMLINK;
+    }
+#endif
+
+    return rtDirNtAdvanceBuffer(pDir);
+}
+
+
+RTDECL(int) RTDirReadEx(RTDIR hDir, PRTDIRENTRYEX pDirEntry, size_t *pcbDirEntry,
+                        RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pDir = hDir;
+    int rc;
+
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pDir, VERR_INVALID_POINTER);
+    AssertReturn(pDir->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pDirEntry, VERR_INVALID_POINTER);
+
+    AssertReturn(enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING && enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                 VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        cbDirEntry = *pcbDirEntry;
+        AssertMsgReturn(cbDirEntry >= RT_UOFFSETOF(RTDIRENTRYEX, szName[2]),
+                        ("Invalid *pcbDirEntry=%zu (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRYEX, szName[2])),
+                        VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Fetch data?
+     */
+    if (!pDir->fDataUnread)
+    {
+        rc = rtDirNtFetchMore(pDir);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+
+    /*
+     * Convert the filename to UTF-8.
+     */
+    rc = rtDirNtConvertCurName(pDir);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Check if we've got enough space to return the data.
+     */
+    const char  *pszName    = pDir->pszName;
+    const size_t cchName    = pDir->cchName;
+    const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRYEX, szName[1]) + cchName;
+    if (pcbDirEntry)
+        *pcbDirEntry = cbRequired;
+    if (cbRequired > cbDirEntry)
+        return VERR_BUFFER_OVERFLOW;
+
+    /*
+     * Setup the returned data.
+     */
+    PFILE_BOTH_DIR_INFORMATION pBoth = pDir->uCurData.pBoth;
+
+    pDirEntry->cbName  = (uint16_t)cchName;  Assert(pDirEntry->cbName == cchName);
+    memcpy(pDirEntry->szName, pszName, cchName + 1);
+    memset(pDirEntry->wszShortName, 0, sizeof(pDirEntry->wszShortName));
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    if (pDir->enmInfoClass != FileMaximumInformation)
+#endif
+    {
+        uint8_t cbShort = pBoth->ShortNameLength;
+        if (cbShort > 0)
+        {
+            AssertStmt(cbShort < sizeof(pDirEntry->wszShortName), cbShort = sizeof(pDirEntry->wszShortName) - 2);
+            memcpy(pDirEntry->wszShortName, pBoth->ShortName, cbShort);
+            pDirEntry->cwcShortName = cbShort / 2;
+        }
+        else
+            pDirEntry->cwcShortName = 0;
+
+        pDirEntry->Info.cbObject    = pBoth->EndOfFile.QuadPart;
+        pDirEntry->Info.cbAllocated = pBoth->AllocationSize.QuadPart;
+
+        Assert(sizeof(uint64_t) == sizeof(pBoth->CreationTime));
+        RTTimeSpecSetNtTime(&pDirEntry->Info.BirthTime,         pBoth->CreationTime.QuadPart);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.AccessTime,        pBoth->LastAccessTime.QuadPart);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.ModificationTime,  pBoth->LastWriteTime.QuadPart);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.ChangeTime,        pBoth->ChangeTime.QuadPart);
+
+        pDirEntry->Info.Attr.fMode  = rtFsModeFromDos((pBoth->FileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT,
+                                                       pszName, cchName, pBoth->EaSize, 0);
+    }
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+    else
+    {
+        pDirEntry->cwcShortName = 0;
+        pDirEntry->Info.cbObject    = 0;
+        pDirEntry->Info.cbAllocated = 0;
+        RTTimeSpecSetNtTime(&pDirEntry->Info.BirthTime,         0);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.AccessTime,        0);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.ModificationTime,  0);
+        RTTimeSpecSetNtTime(&pDirEntry->Info.ChangeTime,        0);
+
+        if (rtNtCompWideStrAndAscii(pDir->uCurData.pObjDir->TypeName.Buffer, pDir->uCurData.pObjDir->TypeName.Length,
+                                    RT_STR_TUPLE("Directory")))
+            pDirEntry->Info.Attr.fMode = RTFS_DOS_DIRECTORY | RTFS_TYPE_DIRECTORY | 0777;
+        else if (rtNtCompWideStrAndAscii(pDir->uCurData.pObjDir->TypeName.Buffer, pDir->uCurData.pObjDir->TypeName.Length,
+                                         RT_STR_TUPLE("SymbolicLink")))
+            pDirEntry->Info.Attr.fMode = RTFS_DOS_NT_REPARSE_POINT | RTFS_TYPE_SYMLINK | 0777;
+        else if (rtNtCompWideStrAndAscii(pDir->uCurData.pObjDir->TypeName.Buffer, pDir->uCurData.pObjDir->TypeName.Length,
+                                         RT_STR_TUPLE("Device")))
+            pDirEntry->Info.Attr.fMode = RTFS_DOS_NT_DEVICE | RTFS_TYPE_DEV_CHAR | 0666;
+        else
+            pDirEntry->Info.Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_FILE | 0666;
+    }
+#endif
+
+    /*
+     * Requested attributes (we cannot provide anything actually).
+     */
+    switch (enmAdditionalAttribs)
+    {
+        case RTFSOBJATTRADD_EASIZE:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+            if (pDir->enmInfoClass == FileMaximumInformation)
+                pDirEntry->Info.Attr.u.EASize.cb        = 0;
+            else
+#endif
+                pDirEntry->Info.Attr.u.EASize.cb        = pBoth->EaSize;
+            break;
+
+        case RTFSOBJATTRADD_UNIX:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+            pDirEntry->Info.Attr.u.Unix.uid             = NIL_RTUID;
+            pDirEntry->Info.Attr.u.Unix.gid             = NIL_RTGID;
+            pDirEntry->Info.Attr.u.Unix.cHardlinks      = 1;
+            pDirEntry->Info.Attr.u.Unix.INodeIdDevice   = pDir->uDirDev;
+            pDirEntry->Info.Attr.u.Unix.INodeId         = 0;
+            if (   pDir->enmInfoClass == FileIdBothDirectoryInformation
+                && pDir->uCurData.pBothId->FileId.QuadPart != UINT64_MAX)
+                pDirEntry->Info.Attr.u.Unix.INodeId     = pDir->uCurData.pBothId->FileId.QuadPart;
+            pDirEntry->Info.Attr.u.Unix.fFlags          = 0;
+            pDirEntry->Info.Attr.u.Unix.GenerationId    = 0;
+            pDirEntry->Info.Attr.u.Unix.Device          = 0;
+            break;
+
+        case RTFSOBJATTRADD_NOTHING:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_NOTHING;
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+            pDirEntry->Info.Attr.u.UnixOwner.uid        = NIL_RTUID;
+            pDirEntry->Info.Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+            pDirEntry->Info.Attr.u.UnixGroup.gid        = NIL_RTGID;
+            pDirEntry->Info.Attr.u.UnixGroup.szName[0]  = '\0';
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    /*
+     * Follow links if requested.
+     */
+    if (   (fFlags & RTPATH_F_FOLLOW_LINK)
+        && RTFS_IS_SYMLINK(fFlags))
+    {
+        /** @todo Symlinks: Find[First|Next]FileW will return info about
+            the link, so RTPATH_F_FOLLOW_LINK is not handled correctly. */
+    }
+
+    /*
+     * Finally advance the buffer.
+     */
+    return rtDirNtAdvanceBuffer(pDir);
+}
+
+
+RTDECL(int) RTDirRewind(RTDIR hDir)
+{
+    /*
+     * Validate and digest input.
+     */
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * The work is done on the next call to rtDirNtFetchMore.
+     */
+    pThis->fRestartScan = true;
+    pThis->fDataUnread  = false;
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTDirQueryInfo(RTDIR hDir, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    PRTDIRINTERNAL pDir = hDir;
+    AssertPtrReturn(pDir, VERR_INVALID_POINTER);
+    AssertReturn(pDir->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING && enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                 VERR_INVALID_PARAMETER);
+
+    if (pDir->enmInfoClass == FileMaximumInformation)
+    {
+        /*
+         * Directory object (see similar code above and rtPathNtQueryInfoInDirectoryObject).
+         */
+        pObjInfo->cbObject    = 0;
+        pObjInfo->cbAllocated = 0;
+        RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         0);
+        RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        0);
+        RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  0);
+        RTTimeSpecSetNtTime(&pObjInfo->ChangeTime,        0);
+        pObjInfo->Attr.fMode = RTFS_DOS_DIRECTORY | RTFS_TYPE_DIRECTORY | 0777;
+        pObjInfo->Attr.enmAdditional = enmAdditionalAttribs;
+        switch (enmAdditionalAttribs)
+        {
+            case RTFSOBJATTRADD_NOTHING:
+            case RTFSOBJATTRADD_UNIX:
+                pObjInfo->Attr.u.Unix.uid             = NIL_RTUID;
+                pObjInfo->Attr.u.Unix.gid             = NIL_RTGID;
+                pObjInfo->Attr.u.Unix.cHardlinks      = 1;
+                pObjInfo->Attr.u.Unix.INodeIdDevice   = pDir->uDirDev;
+                pObjInfo->Attr.u.Unix.INodeId         = 0;
+                pObjInfo->Attr.u.Unix.fFlags          = 0;
+                pObjInfo->Attr.u.Unix.GenerationId    = 0;
+                pObjInfo->Attr.u.Unix.Device          = 0;
+                break;
+
+            case RTFSOBJATTRADD_EASIZE:
+                pObjInfo->Attr.u.EASize.cb            = 0;
+                break;
+
+            case RTFSOBJATTRADD_UNIX_OWNER:
+                pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+                pObjInfo->Attr.u.UnixOwner.uid        = NIL_RTUID;
+                pObjInfo->Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+                break;
+
+            case RTFSOBJATTRADD_UNIX_GROUP:
+                pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+                pObjInfo->Attr.u.UnixGroup.gid        = NIL_RTGID;
+                pObjInfo->Attr.u.UnixGroup.szName[0]  = '\0';
+                break;
+
+            default:
+                AssertMsgFailed(("Impossible!\n"));
+                return VERR_INTERNAL_ERROR_2;
+        }
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Regular directory file.
+     */
+    uint8_t abBuf[_2K];
+    return rtPathNtQueryInfoFromHandle(pDir->hDir, abBuf, sizeof(abBuf), pObjInfo, enmAdditionalAttribs, "", 0);
+}
+
diff --git a/src/VBox/Runtime/r3/nt/dirrel-r3-nt.cpp b/src/VBox/Runtime/r3/nt/dirrel-r3-nt.cpp
new file mode 100644
index 00000000..a4130725
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/dirrel-r3-nt.cpp
@@ -0,0 +1,651 @@
+/* $Id: dirrel-r3-nt.cpp $ */
+/** @file
+ * IPRT - Directory relative base APIs, NT implementation
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/dir.h>
+#include "internal-r3-nt.h"
+
+#include <iprt/assert.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/symlink.h>
+#include <iprt/utf16.h>
+#include "internal/dir.h"
+#include "internal/file.h"
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Getst the RTNTPATHRELATIVEASCENT value for RTNtPathRelativeFromUtf8. */
+#define RTDIRREL_NT_GET_ASCENT(a_pThis) \
+    ( !(pThis->fFlags & RTDIR_F_DENY_ASCENT) ? kRTNtPathRelativeAscent_Allow : kRTNtPathRelativeAscent_Fail )
+
+
+
+/**
+ * Helper that builds a full path for a directory relative path.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The directory.
+ * @param   pszPathDst          The destination buffer.
+ * @param   cbPathDst           The size of the destination buffer.
+ * @param   pszRelPath          The relative path.
+ */
+static int rtDirRelBuildFullPath(PRTDIRINTERNAL pThis, char *pszPathDst, size_t cbPathDst, const char *pszRelPath)
+{
+    AssertMsgReturn(!RTPathStartsWithRoot(pszRelPath), ("pszRelPath='%s'\n", pszRelPath), VERR_PATH_IS_NOT_RELATIVE);
+
+    /*
+     * Let's hope we can avoid checking for ascension.
+     *
+     * Note! We don't take symbolic links into account here.  That can be
+     *       done later if desired.
+     */
+    if (   !(pThis->fFlags & RTDIR_F_DENY_ASCENT)
+        || strstr(pszRelPath, "..") == NULL)
+    {
+        size_t const cchRelPath = strlen(pszRelPath);
+        size_t const cchDirPath = pThis->cchPath;
+        if (cchDirPath + cchRelPath < cbPathDst)
+        {
+            memcpy(pszPathDst, pThis->pszPath, cchDirPath);
+            memcpy(&pszPathDst[cchDirPath], pszRelPath, cchRelPath);
+            pszPathDst[cchDirPath + cchRelPath] = '\0';
+            return VINF_SUCCESS;
+        }
+        return VERR_FILENAME_TOO_LONG;
+    }
+
+    /*
+     * Calc the absolute path using the directory as a base, then check if the result
+     * still starts with the full directory path.
+     *
+     * This ASSUMES that pThis->pszPath is an absolute path.
+     */
+    int rc = RTPathAbsEx(pThis->pszPath, pszRelPath, RTPATH_STR_F_STYLE_HOST, pszPathDst, &cbPathDst);
+    if (RT_SUCCESS(rc))
+    {
+        if (RTPathStartsWith(pszPathDst, pThis->pszPath))
+            return VINF_SUCCESS;
+        return VERR_PATH_NOT_FOUND;
+    }
+    return rc;
+}
+
+
+/*
+ *
+ *
+ * RTFile stuff.
+ * RTFile stuff.
+ * RTFile stuff.
+ *
+ *
+ */
+
+
+RTDECL(int)  RTDirRelFileOpen(RTDIR hDir, const char *pszRelFilename, uint64_t fOpen, PRTFILE phFile)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Validate and convert flags.
+     */
+    uint32_t    fDesiredAccess;
+    uint32_t    fObjAttribs;
+    uint32_t    fFileAttribs;
+    uint32_t    fShareAccess;
+    uint32_t    fCreateDisposition;
+    uint32_t    fCreateOptions;
+    int rc = rtFileNtValidateAndConvertFlags(fOpen, &fDesiredAccess, &fObjAttribs, &fFileAttribs,
+                                             &fShareAccess, &fCreateDisposition, &fCreateOptions);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Convert and normalize the path.
+         */
+        UNICODE_STRING NtName;
+        HANDLE hRoot = pThis->hDir;
+        rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszRelFilename, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+        if (RT_SUCCESS(rc))
+        {
+            HANDLE              hFile = RTNT_INVALID_HANDLE_VALUE;
+            IO_STATUS_BLOCK     Ios   = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+            OBJECT_ATTRIBUTES   ObjAttr;
+            InitializeObjectAttributes(&ObjAttr, &NtName, fObjAttribs, hRoot, NULL /*pSecDesc*/);
+
+            NTSTATUS rcNt = NtCreateFile(&hFile,
+                                         fDesiredAccess,
+                                         &ObjAttr,
+                                         &Ios,
+                                         NULL /* AllocationSize*/,
+                                         fFileAttribs,
+                                         fShareAccess,
+                                         fCreateDisposition,
+                                         fCreateOptions,
+                                         NULL /*EaBuffer*/,
+                                         0 /*EaLength*/);
+            if (NT_SUCCESS(rcNt))
+            {
+                rc = RTFileFromNative(phFile, (uintptr_t)hFile);
+                if (RT_FAILURE(rc))
+                    NtClose(hFile);
+            }
+            else
+                rc = RTErrConvertFromNtStatus(rcNt);
+            RTNtPathFree(&NtName, NULL);
+        }
+    }
+    return rc;
+}
+
+
+
+/*
+ *
+ *
+ * RTDir stuff.
+ * RTDir stuff.
+ * RTDir stuff.
+ *
+ *
+ */
+
+
+/**
+ * Helper for cooking up a path string for rtDirOpenRelativeOrHandle.
+ *
+ * @returns IPRT status code.
+ * @param   pszDst              The destination buffer.
+ * @param   cbDst               The size of the destination buffer.
+ * @param   pThis               The directory this is relative to.
+ * @param   pNtPath             The NT path with a possibly relative path.
+ * @param   fRelative           Whether @a pNtPath is relative or not.
+ * @param   pszPath             The input path.
+ */
+static int rtDirRelJoinPathForDirOpen(char *pszDst, size_t cbDst, PRTDIRINTERNAL pThis,
+                                      PUNICODE_STRING pNtPath, bool fRelative, const char *pszPath)
+{
+    int rc;
+    if (fRelative)
+    {
+        size_t cchRel = 0;
+        rc = RTUtf16CalcUtf8LenEx(pNtPath->Buffer, pNtPath->Length / sizeof(RTUTF16), &cchRel);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+        {
+            if (pThis->cchPath + cchRel < cbDst)
+            {
+                size_t cchBase = pThis->cchPath;
+                memcpy(pszDst, pThis->pszPath, cchBase);
+                pszDst += cchBase;
+                cbDst  -= cchBase;
+                rc = RTUtf16ToUtf8Ex(pNtPath->Buffer, pNtPath->Length / sizeof(RTUTF16), &pszDst, cbDst, NULL);
+            }
+            else
+                rc = VERR_FILENAME_TOO_LONG;
+        }
+    }
+    else
+    {
+        /** @todo would be better to convert pNtName to DOS/WIN path here,
+         *        as it is absolute and doesn't need stuff resolved. */
+        rc = RTPathJoin(pszDst, cbDst, pThis->pszPath, pszPath);
+    }
+    return rc;
+}
+
+RTDECL(int) RTDirRelDirOpen(RTDIR hDir, const char *pszDir, RTDIR *phDir)
+{
+    return RTDirRelDirOpenFiltered(hDir, pszDir, RTDIRFILTER_NONE, 0 /*fFlags*/, phDir);
+}
+
+
+RTDECL(int) RTDirRelDirOpenFiltered(RTDIR hDir, const char *pszDirAndFilter, RTDIRFILTER enmFilter,
+                                    uint32_t fFlags, RTDIR *phDir)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Convert and normalize the path.
+     */
+    UNICODE_STRING NtName;
+    HANDLE hRoot = pThis->hDir;
+    int rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszDirAndFilter, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+    if (RT_SUCCESS(rc))
+    {
+        char szAbsDirAndFilter[RTPATH_MAX];
+        rc = rtDirRelJoinPathForDirOpen(szAbsDirAndFilter, sizeof(szAbsDirAndFilter), pThis,
+                                        &NtName, hRoot != NULL, pszDirAndFilter);
+        if (RT_SUCCESS(rc))
+        {
+            /* Drop the filter from the NT name. */
+            switch (enmFilter)
+            {
+                case RTDIRFILTER_NONE:
+                    break;
+                case RTDIRFILTER_WINNT:
+                case RTDIRFILTER_UNIX:
+                case RTDIRFILTER_UNIX_UPCASED:
+                {
+                    size_t cwc = NtName.Length / sizeof(RTUTF16);
+                    while (   cwc > 0
+                           && NtName.Buffer[cwc - 1] != '\\')
+                        cwc--;
+                    NtName.Buffer[cwc] = '\0';
+                    NtName.Length = (uint16_t)(cwc * sizeof(RTUTF16));
+                    break;
+                }
+                default:
+                    AssertFailedBreak();
+            }
+
+            rc = rtDirOpenRelativeOrHandle(phDir, szAbsDirAndFilter, enmFilter, fFlags, (uintptr_t)hRoot, &NtName);
+        }
+        RTNtPathFree(&NtName, NULL);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelDirCreate(RTDIR hDir, const char *pszRelPath, RTFMODE fMode, uint32_t fCreate, RTDIR *phSubDir)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fCreate & ~RTDIRCREATE_FLAGS_VALID_MASK), VERR_INVALID_FLAGS);
+    fMode = rtFsModeNormalize(fMode, pszRelPath, 0, RTFS_TYPE_DIRECTORY);
+    AssertReturn(rtFsModeIsValidPermissions(fMode), VERR_INVALID_FMODE);
+    AssertPtrNullReturn(phSubDir, VERR_INVALID_POINTER);
+
+    /*
+     * Convert and normalize the path.
+     */
+    UNICODE_STRING NtName;
+    HANDLE hRoot = pThis->hDir;
+    int rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszRelPath, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE              hNewDir = RTNT_INVALID_HANDLE_VALUE;
+        IO_STATUS_BLOCK     Ios     = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        OBJECT_ATTRIBUTES   ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, &NtName, 0 /*fAttrib*/, hRoot, NULL);
+
+        ULONG fDirAttribs = (fCreate & RTFS_DOS_MASK_NT) >> RTFS_DOS_SHIFT;
+        if (!(fCreate & RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_DONT_SET))
+            fDirAttribs |= FILE_ATTRIBUTE_NOT_CONTENT_INDEXED;
+        if (!fDirAttribs)
+            fDirAttribs = FILE_ATTRIBUTE_NORMAL;
+
+        NTSTATUS rcNt = NtCreateFile(&hNewDir,
+                                     phSubDir
+                                     ? FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES | FILE_LIST_DIRECTORY | FILE_TRAVERSE | SYNCHRONIZE
+                                     : SYNCHRONIZE,
+                                     &ObjAttr,
+                                     &Ios,
+                                     NULL /*AllocationSize*/,
+                                     fDirAttribs,
+                                     FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                     FILE_CREATE,
+                                     FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT,
+                                     NULL /*EaBuffer*/,
+                                     0 /*EaLength*/);
+
+        /* Just in case someone takes offence at FILE_ATTRIBUTE_NOT_CONTENT_INDEXED. */
+        if (   (   rcNt == STATUS_INVALID_PARAMETER
+                || rcNt == STATUS_INVALID_PARAMETER_7)
+            && (fDirAttribs & FILE_ATTRIBUTE_NOT_CONTENT_INDEXED)
+            && (fCreate & RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_NOT_CRITICAL) )
+        {
+            fDirAttribs &= ~FILE_ATTRIBUTE_NOT_CONTENT_INDEXED;
+            if (!fDirAttribs)
+                fDirAttribs = FILE_ATTRIBUTE_NORMAL;
+            rcNt = NtCreateFile(&hNewDir,
+                                phSubDir
+                                ? FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES | FILE_LIST_DIRECTORY | FILE_TRAVERSE | SYNCHRONIZE
+                                : SYNCHRONIZE,
+                                &ObjAttr,
+                                &Ios,
+                                NULL /*AllocationSize*/,
+                                fDirAttribs,
+                                FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                FILE_CREATE,
+                                FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT,
+                                NULL /*EaBuffer*/,
+                                0 /*EaLength*/);
+        }
+
+        if (NT_SUCCESS(rcNt))
+        {
+            if (!phSubDir)
+            {
+                NtClose(hNewDir);
+                rc = VINF_SUCCESS;
+            }
+            else
+            {
+                char szAbsDirAndFilter[RTPATH_MAX];
+                rc = rtDirRelJoinPathForDirOpen(szAbsDirAndFilter, sizeof(szAbsDirAndFilter), pThis,
+                                                &NtName, hRoot != NULL, pszRelPath);
+                if (RT_SUCCESS(rc))
+                    rc = rtDirOpenRelativeOrHandle(phSubDir, pszRelPath, RTDIRFILTER_NONE, 0 /*fFlags*/,
+                                                   (uintptr_t)hNewDir, NULL /*pvNativeRelative*/);
+                if (RT_FAILURE(rc))
+                    NtClose(hNewDir);
+            }
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+        RTNtPathFree(&NtName, NULL);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelDirRemove(RTDIR hDir, const char *pszRelPath)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Convert and normalize the path.
+     */
+    UNICODE_STRING NtName;
+    HANDLE hRoot = pThis->hDir;
+    int rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszRelPath, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE              hSubDir = RTNT_INVALID_HANDLE_VALUE;
+        IO_STATUS_BLOCK     Ios     = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        OBJECT_ATTRIBUTES   ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, &NtName, 0 /*fAttrib*/, hRoot, NULL);
+
+        NTSTATUS rcNt = NtCreateFile(&hSubDir,
+                                     DELETE | SYNCHRONIZE,
+                                     &ObjAttr,
+                                     &Ios,
+                                     NULL /*AllocationSize*/,
+                                     FILE_ATTRIBUTE_NORMAL,
+                                     FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                     FILE_OPEN,
+                                     FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_REPARSE_POINT,
+                                     NULL /*EaBuffer*/,
+                                     0 /*EaLength*/);
+        if (NT_SUCCESS(rcNt))
+        {
+            FILE_DISPOSITION_INFORMATION DispInfo;
+            DispInfo.DeleteFile = TRUE;
+            RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+            rcNt = NtSetInformationFile(hSubDir, &Ios, &DispInfo, sizeof(DispInfo), FileDispositionInformation);
+
+            NTSTATUS rcNt2 = NtClose(hSubDir);
+            if (!NT_SUCCESS(rcNt2) && NT_SUCCESS(rcNt))
+                rcNt = rcNt2;
+        }
+
+        if (NT_SUCCESS(rcNt))
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+
+        RTNtPathFree(&NtName, NULL);
+    }
+    return rc;
+}
+
+
+/*
+ *
+ * RTPath stuff.
+ * RTPath stuff.
+ * RTPath stuff.
+ *
+ *
+ */
+
+
+RTDECL(int) RTDirRelPathQueryInfo(RTDIR hDir, const char *pszRelPath, PRTFSOBJINFO pObjInfo,
+                                  RTFSOBJATTRADD enmAddAttr, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Validate and convert flags.
+     */
+    UNICODE_STRING NtName;
+    HANDLE hRoot = pThis->hDir;
+    int rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszRelPath, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+    if (RT_SUCCESS(rc))
+    {
+        if (NtName.Length != 0 || hRoot == NULL)
+            rc = rtPathNtQueryInfoWorker(hRoot, &NtName, pObjInfo, enmAddAttr, fFlags, pszRelPath);
+        else
+            rc = RTDirQueryInfo(hDir, pObjInfo, enmAddAttr);
+       RTNtPathFree(&NtName, NULL);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetMode(RTDIR hDir, const char *pszRelPath, RTFMODE fMode, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    fMode = rtFsModeNormalize(fMode, pszRelPath, 0, 0);
+    AssertReturn(rtFsModeIsValidPermissions(fMode), VERR_INVALID_FMODE);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_FLAGS);
+
+    /*
+     * Convert and normalize the path.
+     */
+    UNICODE_STRING NtName;
+    HANDLE hRoot = pThis->hDir;
+    int rc = RTNtPathRelativeFromUtf8(&NtName, &hRoot, pszRelPath, RTDIRREL_NT_GET_ASCENT(pThis),
+                                      pThis->enmInfoClass == FileMaximumInformation);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE              hSubDir = RTNT_INVALID_HANDLE_VALUE;
+        IO_STATUS_BLOCK     Ios     = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        OBJECT_ATTRIBUTES   ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, &NtName, 0 /*fAttrib*/, hRoot, NULL);
+
+        ULONG fOpenOptions = FILE_OPEN_FOR_BACKUP_INTENT | FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_REPARSE_POINT;
+        if (fFlags & RTPATH_F_ON_LINK)
+            fOpenOptions |= FILE_OPEN_REPARSE_POINT;
+        NTSTATUS rcNt = NtCreateFile(&hSubDir,
+                                     FILE_WRITE_ATTRIBUTES | SYNCHRONIZE,
+                                     &ObjAttr,
+                                     &Ios,
+                                     NULL /*AllocationSize*/,
+                                     FILE_ATTRIBUTE_NORMAL,
+                                     FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+                                     FILE_OPEN,
+                                     fOpenOptions,
+                                     NULL /*EaBuffer*/,
+                                     0 /*EaLength*/);
+        if (NT_SUCCESS(rcNt))
+        {
+            rc = rtNtFileSetModeWorker(hSubDir, fMode);
+
+            rcNt = NtClose(hSubDir);
+            if (!NT_SUCCESS(rcNt) && RT_SUCCESS(rc))
+                rc = RTErrConvertFromNtStatus(rcNt);
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+
+        RTNtPathFree(&NtName, NULL);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetTimes(RTDIR hDir, const char *pszRelPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                                 PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTPathSetTimesEx(szPath, pAccessTime, pModificationTime, pChangeTime, pBirthTime, fFlags);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathSetOwner(RTDIR hDir, const char *pszRelPath, uint32_t uid, uint32_t gid, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+    {
+#ifndef RT_OS_WINDOWS
+        rc = RTPathSetOwnerEx(szPath, uid, gid, fFlags);
+#else
+        rc = VERR_NOT_IMPLEMENTED;
+        RT_NOREF(uid, gid, fFlags);
+#endif
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathRename(RTDIR hDirSrc, const char *pszSrc, RTDIR hDirDst, const char *pszDst, unsigned fRename)
+{
+    PRTDIRINTERNAL pThis = hDirSrc;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    PRTDIRINTERNAL pThat = hDirDst;
+    if (pThat != pThis)
+    {
+        AssertPtrReturn(pThat, VERR_INVALID_HANDLE);
+        AssertReturn(pThat->u32Magic != RTDIR_MAGIC, VERR_INVALID_HANDLE);
+    }
+
+    char szSrcPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szSrcPath, sizeof(szSrcPath), pszSrc);
+    if (RT_SUCCESS(rc))
+    {
+        char szDstPath[RTPATH_MAX];
+        rc = rtDirRelBuildFullPath(pThis, szDstPath, sizeof(szDstPath), pszDst);
+        if (RT_SUCCESS(rc))
+            rc = RTPathRename(szSrcPath, szDstPath, fRename);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelPathUnlink(RTDIR hDir, const char *pszRelPath, uint32_t fUnlink)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszRelPath);
+    if (RT_SUCCESS(rc))
+        rc = RTPathUnlink(szPath, fUnlink);
+    return rc;
+}
+
+
+/*
+ *
+ * RTSymlink stuff.
+ * RTSymlink stuff.
+ * RTSymlink stuff.
+ *
+ *
+ */
+
+
+RTDECL(int) RTDirRelSymlinkCreate(RTDIR hDir, const char *pszSymlink, const char *pszTarget,
+                                  RTSYMLINKTYPE enmType, uint32_t fCreate)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszSymlink);
+    if (RT_SUCCESS(rc))
+        rc = RTSymlinkCreate(szPath, pszTarget, enmType, fCreate);
+    return rc;
+}
+
+
+RTDECL(int) RTDirRelSymlinkRead(RTDIR hDir, const char *pszSymlink, char *pszTarget, size_t cbTarget, uint32_t fRead)
+{
+    PRTDIRINTERNAL pThis = hDir;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTDIR_MAGIC, VERR_INVALID_HANDLE);
+
+    char szPath[RTPATH_MAX];
+    int rc = rtDirRelBuildFullPath(pThis, szPath, sizeof(szPath), pszSymlink);
+    if (RT_SUCCESS(rc))
+        rc = RTSymlinkRead(szPath, pszTarget, cbTarget, fRead);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/nt/fs-nt.cpp b/src/VBox/Runtime/r3/nt/fs-nt.cpp
new file mode 100644
index 00000000..70add1ee
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/fs-nt.cpp
@@ -0,0 +1,279 @@
+/* $Id: fs-nt.cpp $ */
+/** @file
+ * IPRT - File System, Native NT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FS
+#include "internal-r3-nt.h"
+
+#include <iprt/fs.h>
+#include <iprt/file.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/param.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include "internal/fs.h"
+
+
+
+
+RTR3DECL(int) RTFsQuerySizes(const char *pszFsPath, RTFOFF *pcbTotal, RTFOFF *pcbFree,
+                             uint32_t *pcbBlock, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+
+    /*
+     * Open the file/dir/whatever.
+     */
+    HANDLE hFile;
+    int rc = RTNtPathOpen(pszFsPath,
+                          GENERIC_READ,
+                          FILE_ATTRIBUTE_NORMAL,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                          FILE_OPEN,
+                          FILE_OPEN_FOR_BACKUP_INTENT,
+                          OBJ_CASE_INSENSITIVE,
+                          &hFile,
+                          NULL);
+    if (RT_SUCCESS(rc))
+    {
+        RTFILE hIprtFile = NIL_RTFILE;
+        rc = RTFileFromNative(&hIprtFile, (RTHCINTPTR)hFile);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+            rc = RTFileQueryFsSizes(hIprtFile, pcbTotal, pcbFree, pcbBlock, pcbSector);
+
+        RTNtPathClose(hFile);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTFsQuerySerial(const char *pszFsPath, uint32_t *pu32Serial)
+{
+    /*
+     * Validate & get valid root path.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertPtrReturn(pu32Serial, VERR_INVALID_POINTER);
+
+    /*
+     * Open the file/dir/whatever.
+     */
+    HANDLE hFile;
+    int rc = RTNtPathOpen(pszFsPath,
+                          GENERIC_READ,
+                          FILE_ATTRIBUTE_NORMAL,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                          FILE_OPEN,
+                          FILE_OPEN_FOR_BACKUP_INTENT,
+                          OBJ_CASE_INSENSITIVE,
+                          &hFile,
+                          NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Get the volume information.
+         */
+        union
+        {
+             FILE_FS_VOLUME_INFORMATION FsVolInfo;
+             uint8_t abBuf[sizeof(FILE_FS_VOLUME_INFORMATION) + 4096];
+        } u;
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NTSTATUS rcNt = NtQueryVolumeInformationFile(hFile, &Ios, &u, sizeof(u), FileFsVolumeInformation);
+        if (NT_SUCCESS(rcNt))
+            *pu32Serial = u.FsVolInfo.VolumeSerialNumber;
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+
+        RTNtPathClose(hFile);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTFsQueryProperties(const char *pszFsPath, PRTFSPROPERTIES pProperties)
+{
+    /*
+     * Validate & get valid root path.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertPtrReturn(pProperties, VERR_INVALID_POINTER);
+
+    /*
+     * Open the file/dir/whatever.
+     */
+    HANDLE hFile;
+    int rc = RTNtPathOpen(pszFsPath,
+                          GENERIC_READ,
+                          FILE_ATTRIBUTE_NORMAL,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                          FILE_OPEN,
+                          FILE_OPEN_FOR_BACKUP_INTENT,
+                          OBJ_CASE_INSENSITIVE,
+                          &hFile,
+                          NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Get the volume information.
+         */
+        union
+        {
+            FILE_FS_ATTRIBUTE_INFORMATION FsAttrInfo;
+            uint8_t abBuf[sizeof(FILE_FS_ATTRIBUTE_INFORMATION) + 4096];
+        } u;
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NTSTATUS rcNt = NtQueryVolumeInformationFile(hFile, &Ios, &u, sizeof(u), FileFsAttributeInformation);
+        if (NT_SUCCESS(rcNt))
+        {
+            FILE_FS_DEVICE_INFORMATION FsDevInfo;
+            rcNt = NtQueryVolumeInformationFile(hFile, &Ios, &FsDevInfo, sizeof(FsDevInfo), FileFsDeviceInformation);
+            if (NT_SUCCESS(rcNt))
+            {
+                /*
+                 * Fill in the return structure.
+                 */
+                memset(pProperties, 0, sizeof(*pProperties));
+                pProperties->cbMaxComponent   = u.FsAttrInfo.MaximumComponentNameLength;
+                pProperties->fFileCompression = !!(u.FsAttrInfo.FileSystemAttributes & FILE_FILE_COMPRESSION);
+                pProperties->fCompressed      = !!(u.FsAttrInfo.FileSystemAttributes & FILE_VOLUME_IS_COMPRESSED);
+                pProperties->fReadOnly        = !!(u.FsAttrInfo.FileSystemAttributes & FILE_READ_ONLY_VOLUME);
+                pProperties->fSupportsUnicode = !!(u.FsAttrInfo.FileSystemAttributes & FILE_UNICODE_ON_DISK);
+                pProperties->fCaseSensitive   = false;    /* win32 is case preserving only */
+                /** @todo r=bird: What about FILE_CASE_SENSITIVE_SEARCH ?  Is this set for NTFS
+                 *        as well perchance?  If so, better mention it instead of just setting
+                 *        fCaseSensitive to false. */
+
+                /* figure the remote stuff */
+                pProperties->fRemote          = RT_BOOL(FsDevInfo.Characteristics & FILE_REMOTE_DEVICE);
+            }
+            else
+                rc = RTErrConvertFromNtStatus(rcNt);
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+
+        RTNtPathClose(hFile);
+    }
+    return rc;
+}
+
+
+RTR3DECL(bool) RTFsIsCaseSensitive(const char *pszFsPath)
+{
+    RT_NOREF_PV(pszFsPath);
+    return false;
+}
+
+
+int rtNtQueryFsType(HANDLE hHandle, PRTFSTYPE penmType)
+{
+    /*
+     * Get the file system name.
+     */
+    union
+    {
+        FILE_FS_ATTRIBUTE_INFORMATION FsAttrInfo;
+        uint8_t abBuf[sizeof(FILE_FS_ATTRIBUTE_INFORMATION) + 4096];
+    } u;
+    IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    NTSTATUS rcNt = NtQueryVolumeInformationFile(hHandle, &Ios, &u, sizeof(u), FileFsAttributeInformation);
+    if (NT_SUCCESS(rcNt))
+    {
+#define IS_FS(a_szName) rtNtCompWideStrAndAscii(u.FsAttrInfo.FileSystemName, u.FsAttrInfo.FileSystemNameLength, RT_STR_TUPLE(a_szName))
+        if (IS_FS("NTFS"))
+            *penmType = RTFSTYPE_NTFS;
+        else if (IS_FS("FAT"))
+            *penmType = RTFSTYPE_FAT;
+        else if (IS_FS("FAT32"))
+            *penmType = RTFSTYPE_FAT;
+        else if (IS_FS("exFAT"))
+            *penmType = RTFSTYPE_EXFAT;
+        else if (IS_FS("UDF"))
+            *penmType = RTFSTYPE_UDF;
+        else if (IS_FS("CDFS"))
+            *penmType = RTFSTYPE_ISO9660;
+        else if (IS_FS("HPFS"))
+            *penmType = RTFSTYPE_HPFS;
+        else if (IS_FS("ReFS")) /** @todo verify ReFS signature. */
+            *penmType = RTFSTYPE_REFS;
+        else if (IS_FS("VBoxSharedFolderFS"))
+            *penmType = RTFSTYPE_VBOXSHF;
+#undef IS_FS
+        return VINF_SUCCESS;
+    }
+
+    *penmType = RTFSTYPE_UNKNOWN;
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
+
+RTR3DECL(int) RTFsQueryType(const char *pszFsPath, PRTFSTYPE penmType)
+{
+    /*
+     * Validate input.
+     */
+    *penmType = RTFSTYPE_UNKNOWN;
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * Open the file/dir/whatever.
+     */
+    HANDLE hFile;
+    int rc = RTNtPathOpen(pszFsPath,
+                          GENERIC_READ,
+                          FILE_ATTRIBUTE_NORMAL,
+                          FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                          FILE_OPEN,
+                          FILE_OPEN_FOR_BACKUP_INTENT,
+                          OBJ_CASE_INSENSITIVE,
+                          &hFile,
+                          NULL);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtNtQueryFsType(hFile, penmType);
+        RTNtPathClose(hFile);
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/nt/internal-r3-nt.h b/src/VBox/Runtime/r3/nt/internal-r3-nt.h
new file mode 100644
index 00000000..c76a3f6b
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/internal-r3-nt.h
@@ -0,0 +1,92 @@
+/* $Id: internal-r3-nt.h $ */
+/** @file
+ * IPRT - Internal Header for the Native NT code.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_nt_internal_r3_nt_h
+#define IPRT_INCLUDED_SRC_r3_nt_internal_r3_nt_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#ifdef IN_SUP_HARDENED_R3
+# include <iprt/nt/nt-and-windows.h>
+#else
+# include <iprt/nt/nt.h>
+#endif
+#include "internal/iprt.h"
+
+
+#if 1
+/** Enables the "\\!\" NT path pass thru as well as hacks for listing NT object
+ * directories. */
+# define IPRT_WITH_NT_PATH_PASSTHRU 1
+#endif
+
+
+
+/**
+ * Internal helper for comparing a WCHAR string with a char string.
+ *
+ * @returns @c true if equal, @c false if not.
+ * @param   pwsz1               The first string.
+ * @param   cch1                The length of the first string, in bytes.
+ * @param   psz2                The second string.
+ * @param   cch2                The length of the second string.
+ */
+DECLINLINE(bool) rtNtCompWideStrAndAscii(WCHAR const *pwsz1, size_t cch1, const char *psz2, size_t cch2)
+{
+    if (cch1 != cch2 * 2)
+        return false;
+    while (cch2-- > 0)
+    {
+        unsigned ch1 = *pwsz1++;
+        unsigned ch2 = (unsigned char)*psz2++;
+        if (ch1 != ch2)
+            return false;
+    }
+    return true;
+}
+
+#endif /* !IPRT_INCLUDED_SRC_r3_nt_internal_r3_nt_h */
+
+/**
+ * Common worker for RTFileSetMode, RTPathSetMode and RTDirRelPathSetMode.
+ *
+ * @returns IPRT status code.
+ * @param   hNativeFile The NT handle to the file system object.
+ * @param   fMode       Valid and normalized file mode mask to set.
+ */
+DECLHIDDEN(int) rtNtFileSetModeWorker(HANDLE hNativeFile, RTFMODE fMode);
+
diff --git a/src/VBox/Runtime/r3/nt/pathint-nt.cpp b/src/VBox/Runtime/r3/nt/pathint-nt.cpp
new file mode 100644
index 00000000..95281ca7
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/pathint-nt.cpp
@@ -0,0 +1,1161 @@
+/* $Id: pathint-nt.cpp $ */
+/** @file
+ * IPRT - Native NT, Internal Path stuff.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FS
+#include "internal-r3-nt.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static char const g_szPrefixUnc[]      = "\\??\\UNC\\";
+static char const g_szPrefix[]         = "\\??\\";
+static char const g_szPrefixNt3xUnc[]  = "\\DosDevices\\UNC\\";
+static char const g_szPrefixNt3x[]     = "\\DosDevices\\";
+
+
+/**
+ * Handles the pass thru case for UTF-8 input.
+ * Win32 path uses "\\?\" prefix which is converted to "\??\" NT prefix.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.
+ * @param   phRootDir           Where to return the root handle, if applicable.
+ * @param   pszPath             The UTF-8 path.
+ */
+static int rtNtPathFromWinUtf8PassThru(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir, const char *pszPath)
+{
+    PRTUTF16 pwszPath = NULL;
+    size_t   cwcLen;
+    int rc = RTStrToUtf16Ex(pszPath, RTSTR_MAX, &pwszPath, 0, &cwcLen);
+    if (RT_SUCCESS(rc))
+    {
+        if (cwcLen < _32K - 1)
+        {
+            *phRootDir = NULL;
+            if (RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion) >= RT_MAKE_U64(0, 4))
+            {
+                pwszPath[0] = '\\';
+                pwszPath[1] = '?';
+                pwszPath[2] = '?';
+                pwszPath[3] = '\\';
+
+                pNtName->Buffer = pwszPath;
+                pNtName->Length = (uint16_t)(cwcLen * sizeof(RTUTF16));
+                pNtName->MaximumLength = pNtName->Length + sizeof(RTUTF16);
+                return VINF_SUCCESS;
+            }
+
+            rc = RTUtf16Realloc(&pwszPath, cwcLen + sizeof(g_szPrefixNt3x));
+            if (RT_SUCCESS(rc))
+            {
+                memmove(&pwszPath[sizeof(g_szPrefixNt3x) - 1], &pwszPath[4], (cwcLen - 4 + 1) * sizeof(RTUTF16));
+                for (uint32_t i = 0; i < sizeof(g_szPrefixNt3x) - 1; i++)
+                    pwszPath[i] = g_szPrefixNt3x[i];
+
+                pNtName->Buffer = pwszPath;
+                pNtName->Length = (uint16_t)((cwcLen - 4 + sizeof(g_szPrefixNt3x) - 1) * sizeof(RTUTF16));
+                pNtName->MaximumLength = pNtName->Length + sizeof(RTUTF16);
+                return VINF_SUCCESS;
+            }
+        }
+
+        RTUtf16Free(pwszPath);
+        rc = VERR_FILENAME_TOO_LONG;
+    }
+    return rc;
+}
+
+
+/**
+ * Handles the pass thru case for UTF-16 input.
+ * Win32 path uses "\\?\" prefix which is converted to "\??\" NT prefix.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.
+ * @param   phRootDir           Stores NULL here, as we don't use it.
+ * @param   pwszWinPath         The UTF-16 windows-style path.
+ * @param   cwcWinPath          The length of the windows-style input path.
+ */
+static int rtNtPathFromWinUtf16PassThru(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir,
+                                        PCRTUTF16 pwszWinPath, size_t cwcWinPath)
+{
+    /* Check length and allocate memory for it. */
+    int rc;
+    if (cwcWinPath < _32K - 1)
+    {
+
+        size_t const cwcExtraPrefix =    RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion)
+                                      >= RT_MAKE_U64(0, 4)
+                                    ? 0 : sizeof(g_szPrefixNt3x) - 1 - 4;
+        PRTUTF16 pwszNtPath = (PRTUTF16)RTUtf16Alloc((cwcExtraPrefix + cwcWinPath + 1) * sizeof(RTUTF16));
+        if (pwszNtPath)
+        {
+            /* Intialize the path. */
+            if (!cwcExtraPrefix)
+            {
+                pwszNtPath[0] = '\\';
+                pwszNtPath[1] = '?';
+                pwszNtPath[2] = '?';
+                pwszNtPath[3] = '\\';
+            }
+            else
+                for (uint32_t i = 0; i < sizeof(g_szPrefixNt3x) - 1; i++)
+                    pwszNtPath[i] = g_szPrefixNt3x[i];
+            memcpy(pwszNtPath + cwcExtraPrefix + 4, pwszWinPath + 4, (cwcWinPath - 4) * sizeof(RTUTF16));
+            pwszNtPath[cwcExtraPrefix + cwcWinPath] = '\0';
+
+            /* Initialize the return values. */
+            pNtName->Buffer = pwszNtPath;
+            pNtName->Length = (uint16_t)(cwcExtraPrefix + cwcWinPath * sizeof(RTUTF16));
+            pNtName->MaximumLength = pNtName->Length + sizeof(RTUTF16);
+            *phRootDir = NULL;
+
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = VERR_NO_UTF16_MEMORY;
+    }
+    else
+        rc = VERR_FILENAME_TOO_LONG;
+    return rc;
+}
+
+
+
+
+
+/**
+ * Converts the path to UTF-16 and sets all the return values.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.
+ * @param   phRootDir           Where to return the root handle, if applicable.
+ * @param   pszPath             The UTF-8 path.
+ */
+static int rtNtPathUtf8ToUniStr(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir, const char *pszPath)
+{
+    PRTUTF16 pwszPath = NULL;
+    size_t   cwcLen;
+    int rc = RTStrToUtf16Ex(pszPath, RTSTR_MAX, &pwszPath, 0, &cwcLen);
+    if (RT_SUCCESS(rc))
+    {
+        if (cwcLen < _32K - 1)
+        {
+            pNtName->Buffer = pwszPath;
+            pNtName->Length = (uint16_t)(cwcLen * sizeof(RTUTF16));
+            pNtName->MaximumLength = pNtName->Length + sizeof(RTUTF16);
+            *phRootDir = NULL;
+            return VINF_SUCCESS;
+        }
+
+        RTUtf16Free(pwszPath);
+        rc = VERR_FILENAME_TOO_LONG;
+    }
+    return rc;
+}
+
+
+/**
+ * Converts a windows-style path to NT format and encoding.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.  Free using
+ *                              rtTNtPathToNative.
+ * @param   phRootDir           Where to return the root handle, if applicable.
+ * @param   pszPath             The UTF-8 path.
+ */
+static int rtNtPathToNative(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir, const char *pszPath)
+{
+/** @todo This code sucks a bit performance wise, esp. calling
+ *        generic RTPathAbs.  Too many buffers involved, I think. */
+
+    /*
+     * Very simple conversion of a win32-like path into an NT path.
+     */
+    const char *pszPrefix;
+    size_t      cchPrefix;
+    if (RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion) >= RT_MAKE_U64(0, 4))
+    {
+        pszPrefix = g_szPrefix;
+        cchPrefix = sizeof(g_szPrefix) - 1;
+    }
+    else
+    {
+        pszPrefix = g_szPrefixNt3x;
+        cchPrefix = sizeof(g_szPrefixNt3x) - 1;
+    }
+
+    size_t      cchSkip   = 0;
+    if (   RTPATH_IS_SLASH(pszPath[0])
+        && RTPATH_IS_SLASH(pszPath[1])
+        && !RTPATH_IS_SLASH(pszPath[2])
+        && pszPath[2])
+    {
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+        /*
+         * Special trick: The path starts with RTPATH_NT_PASSTHRU_PREFIX, we will skip past the bang and pass it thru.
+         */
+        if (   pszPath[2] == ':'
+            && pszPath[3] == 'i'
+            && pszPath[4] == 'p'
+            && pszPath[5] == 'r'
+            && pszPath[6] == 't'
+            && pszPath[7] == 'n'
+            && pszPath[8] == 't'
+            && pszPath[9] == ':'
+            && RTPATH_IS_SLASH(pszPath[10]))
+            return rtNtPathUtf8ToUniStr(pNtName, phRootDir, pszPath + 10);
+#endif
+
+        if (   pszPath[2] == '?'
+            && RTPATH_IS_SLASH(pszPath[3]))
+            return rtNtPathFromWinUtf8PassThru(pNtName, phRootDir, pszPath);
+
+        if (   pszPath[2] == '.'
+            && RTPATH_IS_SLASH(pszPath[3]))
+        {
+            /*
+             * Device path.
+             * Note! I suspect \\.\stuff\..\otherstuff may be handled differently by windows.
+             */
+            cchSkip   = 4;
+        }
+        else
+        {
+            /* UNC */
+            if (RT_MAKE_U64(RTNtCurrentPeb()->OSMinorVersion, RTNtCurrentPeb()->OSMajorVersion) >= RT_MAKE_U64(0, 4))
+            {
+                pszPrefix = g_szPrefixUnc;
+                cchPrefix = sizeof(g_szPrefixUnc) - 1;
+            }
+            else
+            {
+                pszPrefix = g_szPrefixNt3xUnc;
+                cchPrefix = sizeof(g_szPrefixNt3xUnc) - 1;
+            }
+            cchSkip   = 2;
+        }
+    }
+
+    /*
+     * Straighten out all .. and uncessary . references and convert slashes.
+     */
+    char    szAbsPathBuf[RTPATH_MAX];
+    size_t  cbAbsPath      = sizeof(szAbsPathBuf) - (cchPrefix - cchSkip);
+    char   *pszAbsPath     = szAbsPathBuf;
+    char   *pszAbsPathFree = NULL;
+    int rc = RTPathAbsEx(NULL, pszPath, RTPATH_STR_F_STYLE_DOS, &pszAbsPath[cchPrefix - cchSkip], &cbAbsPath);
+    if (RT_SUCCESS(rc))
+    { /* likely */ }
+    else if (rc == VERR_BUFFER_OVERFLOW)
+    {
+        unsigned cTries       = 8;
+        size_t   cbAbsPathBuf = RTPATH_MAX;
+        for (;;)
+        {
+            cbAbsPathBuf = RT_MAX(RT_ALIGN_Z((cchPrefix - cchSkip) + cbAbsPath + 32, 64), cbAbsPathBuf + 256);
+            if (cTries == 1)
+                cbAbsPathBuf = RT_MAX(cbAbsPathBuf, RTPATH_BIG_MAX * 2);
+            pszAbsPathFree = pszAbsPath = (char *)RTMemTmpAlloc(cbAbsPathBuf);
+            if (!pszAbsPath)
+                return VERR_NO_TMP_MEMORY;
+
+            cbAbsPath = cbAbsPathBuf - (cchPrefix - cchSkip);
+            rc = RTPathAbsEx(NULL, pszPath, RTPATH_STR_F_STYLE_DOS, &pszAbsPath[cchPrefix - cchSkip], &cbAbsPath);
+            if (RT_SUCCESS(rc))
+                break;
+            RTMemTmpFree(pszAbsPathFree);
+            pszAbsPathFree = NULL;
+            if (rc != VERR_BUFFER_OVERFLOW)
+                return rc;
+            if (--cTries == 0)
+                return VERR_FILENAME_TOO_LONG;
+        }
+    }
+    else
+        return rc;
+
+    /*
+     * Add prefix and convert it to UTF16.
+     */
+    memcpy(pszAbsPath, pszPrefix, cchPrefix);
+    rc = rtNtPathUtf8ToUniStr(pNtName, phRootDir, pszAbsPath);
+
+    if (pszAbsPathFree)
+        RTMemTmpFree(pszAbsPathFree);
+    return rc;
+}
+
+
+/**
+ * Converts a windows-style path to NT format and encoding.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.  Free using
+ *                              RTNtPathToNative.
+ * @param   phRootDir           Where to return the root handle, if applicable.
+ * @param   pszPath             The UTF-8 path.
+ */
+RTDECL(int) RTNtPathFromWinUtf8(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir, const char *pszPath)
+{
+    return rtNtPathToNative(pNtName, phRootDir, pszPath);
+}
+
+
+/**
+ * Converts a UTF-16 windows-style path to NT format.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.  Free using
+ *                              RTNtPathFree.
+ * @param   phRootDir           Where to return the root handle, if applicable.
+ * @param   pwszWinPath         The UTF-16 windows-style path.
+ * @param   cwcWinPath          The max length of the windows-style path in
+ *                              RTUTF16 units.  Use RTSTR_MAX if unknown and @a
+ *                              pwszWinPath is correctly terminated.
+ */
+RTDECL(int) RTNtPathFromWinUtf16Ex(struct _UNICODE_STRING *pNtName, HANDLE *phRootDir, PCRTUTF16 pwszWinPath, size_t cwcWinPath)
+{
+    /*
+     * Validate the input, calculating the correct length.
+     */
+    if (cwcWinPath == 0 || *pwszWinPath == '\0')
+        return VERR_INVALID_NAME;
+
+    RTUtf16NLenEx(pwszWinPath, cwcWinPath, &cwcWinPath);
+    int rc = RTUtf16ValidateEncodingEx(pwszWinPath, cwcWinPath, 0);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Very simple conversion of a win32-like path into an NT path.
+     */
+    const char *pszPrefix = g_szPrefix;
+    size_t      cchPrefix = sizeof(g_szPrefix) - 1;
+    size_t      cchSkip   = 0;
+
+    if (   RTPATH_IS_SLASH(pwszWinPath[0])
+        && cwcWinPath >= 3
+        && RTPATH_IS_SLASH(pwszWinPath[1])
+        && !RTPATH_IS_SLASH(pwszWinPath[2]) )
+    {
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+        /*
+         * Special trick: The path starts with RTPATH_NT_PASSTHRU_PREFIX, we will skip past the bang and pass it thru.
+         */
+        if (   cwcWinPath >= sizeof(RTPATH_NT_PASSTHRU_PREFIX) - 1U
+            && pwszWinPath[2] == ':'
+            && pwszWinPath[3] == 'i'
+            && pwszWinPath[4] == 'p'
+            && pwszWinPath[5] == 'r'
+            && pwszWinPath[6] == 't'
+            && pwszWinPath[7] == 'n'
+            && pwszWinPath[8] == 't'
+            && pwszWinPath[9] == ':'
+            && RTPATH_IS_SLASH(pwszWinPath[10]) )
+        {
+            pwszWinPath += 10;
+            cwcWinPath  -= 10;
+            if (cwcWinPath < _32K - 1)
+            {
+                PRTUTF16 pwszNtPath = RTUtf16Alloc((cwcWinPath + 1) * sizeof(RTUTF16));
+                if (pwszNtPath)
+                {
+                    memcpy(pwszNtPath, pwszWinPath, cwcWinPath * sizeof(RTUTF16));
+                    pwszNtPath[cwcWinPath] = '\0';
+                    pNtName->Buffer = pwszNtPath;
+                    pNtName->Length = (uint16_t)(cwcWinPath * sizeof(RTUTF16));
+                    pNtName->MaximumLength = pNtName->Length + sizeof(RTUTF16);
+                    *phRootDir = NULL;
+                    return VINF_SUCCESS;
+                }
+                rc = VERR_NO_UTF16_MEMORY;
+            }
+            else
+                rc = VERR_FILENAME_TOO_LONG;
+            return rc;
+        }
+#endif
+
+        if (   pwszWinPath[2] == '?'
+            && cwcWinPath >= 4
+            && RTPATH_IS_SLASH(pwszWinPath[3]))
+            return rtNtPathFromWinUtf16PassThru(pNtName, phRootDir, pwszWinPath, cwcWinPath);
+
+        if (   pwszWinPath[2] == '.'
+            && cwcWinPath >= 4
+            && RTPATH_IS_SLASH(pwszWinPath[3]))
+        {
+            /*
+             * Device path.
+             * Note! I suspect \\.\stuff\..\otherstuff may be handled differently by windows.
+             */
+            cchSkip   = 4;
+        }
+        else
+        {
+            /* UNC */
+            pszPrefix = g_szPrefixUnc;
+            cchPrefix = sizeof(g_szPrefixUnc) - 1;
+            cchSkip   = 2;
+        }
+    }
+
+    /*
+     * Straighten out all .. and unnecessary . references and convert slashes.
+     */
+    /* UTF-16 -> UTF-8 (relative path) */
+    char   szRelPath[RTPATH_MAX];
+    char  *pszRelPathFree = NULL;
+    char  *pszRelPath = szRelPath;
+    size_t cchRelPath;
+    rc = RTUtf16ToUtf8Ex(pwszWinPath, cwcWinPath, &pszRelPath, sizeof(szRelPath), &cchRelPath);
+    if (RT_SUCCESS(rc))
+    { /* likely */ }
+    else if (rc == VERR_BUFFER_OVERFLOW)
+    {
+        pszRelPath = NULL;
+        rc = RTUtf16ToUtf8Ex(pwszWinPath, cwcWinPath, &pszRelPath, 0, &cchRelPath);
+        if (RT_SUCCESS(rc))
+            pszRelPathFree = pszRelPath;
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /* Relative -> Absolute. */
+        char   szAbsPathBuf[RTPATH_MAX];
+        char  *pszAbsPathFree = NULL;
+        char  *pszAbsPath     = szAbsPathBuf;
+        size_t cbAbsPath      = sizeof(szAbsPathBuf) - (cchPrefix - cchSkip);
+        rc = RTPathAbsEx(NULL, szRelPath, RTPATH_STR_F_STYLE_DOS, &pszAbsPath[cchPrefix - cchSkip], &cbAbsPath);
+        if (RT_SUCCESS(rc))
+        { /* likely */ }
+        else if (rc == VERR_BUFFER_OVERFLOW)
+        {
+            unsigned cTries = 8;
+            size_t   cbAbsPathBuf = RTPATH_MAX;
+            for (;;)
+            {
+                cbAbsPathBuf = RT_MAX(RT_ALIGN_Z((cchPrefix - cchSkip) + cbAbsPath + 32, 64), cbAbsPathBuf + 256);
+                if (cTries == 1)
+                    cbAbsPathBuf = RT_MAX(cbAbsPathBuf, RTPATH_BIG_MAX * 2);
+                pszAbsPathFree = pszAbsPath = (char *)RTMemTmpAlloc(cbAbsPathBuf);
+                if (!pszAbsPath)
+                {
+                    rc = VERR_NO_TMP_MEMORY;
+                    break;
+                }
+
+                cbAbsPath = cbAbsPathBuf - (cchPrefix - cchSkip);
+                rc = RTPathAbsEx(NULL, szRelPath, RTPATH_STR_F_STYLE_DOS, &pszAbsPath[cchPrefix - cchSkip], &cbAbsPath);
+                if (RT_SUCCESS(rc))
+                    break;
+
+                RTMemTmpFree(pszAbsPathFree);
+                pszAbsPathFree = NULL;
+                if (rc != VERR_BUFFER_OVERFLOW)
+                    break;
+                if (--cTries == 0)
+                {
+                    rc = VERR_FILENAME_TOO_LONG;
+                    break;
+                }
+            }
+
+        }
+        if (pszRelPathFree)
+            RTStrFree(pszRelPathFree);
+
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Add prefix
+             */
+            memcpy(pszAbsPath, pszPrefix, cchPrefix);
+
+            /*
+             * Remove trailing '.' that is used to specify no extension in the Win32/DOS world.
+             */
+            size_t cchAbsPath = strlen(pszAbsPath);
+            if (   cchAbsPath > 2
+                && pszAbsPath[cchAbsPath - 1] == '.')
+            {
+                char const ch = pszAbsPath[cchAbsPath - 2];
+                if (   ch != '/'
+                    && ch != '\\'
+                    && ch != ':'
+                    && ch != '.')
+                    pszAbsPath[--cchAbsPath] = '\0';
+            }
+
+            /*
+             * Finally convert to UNICODE_STRING.
+             */
+            rc = rtNtPathUtf8ToUniStr(pNtName, phRootDir, pszAbsPath);
+
+            if (pszAbsPathFree)
+                RTMemTmpFree(pszAbsPathFree);
+        }
+    }
+    return rc;
+}
+
+
+/**
+ * Ensures that the NT string has sufficient storage to hold @a cwcMin RTUTF16
+ * chars plus a terminator.
+ *
+ * The NT string must have been returned by RTNtPathFromWinUtf8 or
+ * RTNtPathFromWinUtf16Ex.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             The NT path string.
+ * @param   cwcMin              The minimum number of RTUTF16 chars. Max 32767.
+ * @sa      RTNtPathFree
+ */
+RTDECL(int) RTNtPathEnsureSpace(struct _UNICODE_STRING *pNtName, size_t cwcMin)
+{
+    if (pNtName->MaximumLength / sizeof(RTUTF16) > cwcMin)
+        return VINF_SUCCESS;
+
+    AssertReturn(cwcMin < _64K / sizeof(RTUTF16), VERR_OUT_OF_RANGE);
+
+    size_t const cbMin = (cwcMin + 1) * sizeof(RTUTF16);
+    int rc = RTUtf16Realloc(&pNtName->Buffer, cbMin);
+    if (RT_SUCCESS(rc))
+        pNtName->MaximumLength = (uint16_t)cbMin;
+    return rc;
+}
+
+
+/**
+ * Gets the NT path to the object represented by the given handle.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT path.  Free using
+ *                              RTNtPathFree.
+ * @param   hHandle             The handle.
+ * @param   cwcExtra            How much extra space is needed.
+ */
+RTDECL(int) RTNtPathFromHandle(struct _UNICODE_STRING *pNtName, HANDLE hHandle, size_t cwcExtra)
+{
+    /*
+     * Query the name into a buffer.
+     */
+    ULONG cbBuf = _2K;
+    PUNICODE_STRING pUniStrBuf = (PUNICODE_STRING)RTMemTmpAllocZ(cbBuf);
+    if (!pUniStrBuf)
+        return VERR_NO_TMP_MEMORY;
+
+    ULONG cbNameBuf = cbBuf;
+    NTSTATUS rcNt = NtQueryObject(hHandle, ObjectNameInformation, pUniStrBuf, cbBuf, &cbNameBuf);
+    while (   rcNt == STATUS_BUFFER_OVERFLOW
+           || rcNt == STATUS_BUFFER_TOO_SMALL)
+    {
+        do
+            cbBuf *= 2;
+        while (cbBuf <= cbNameBuf);
+        RTMemTmpFree(pUniStrBuf);
+        pUniStrBuf = (PUNICODE_STRING)RTMemTmpAllocZ(cbBuf);
+        if (!pUniStrBuf)
+            return VERR_NO_TMP_MEMORY;
+
+        cbNameBuf = cbBuf;
+        rcNt = NtQueryObject(hHandle, ObjectNameInformation, pUniStrBuf, cbBuf, &cbNameBuf);
+    }
+    int rc;
+    if (NT_SUCCESS(rcNt))
+    {
+        /*
+         * Copy the result into the return string.
+         */
+        size_t cbNeeded = cwcExtra * sizeof(RTUTF16) + pUniStrBuf->Length + sizeof(RTUTF16);
+        if (cbNeeded < _64K)
+        {
+            pNtName->Length        = pUniStrBuf->Length;
+            pNtName->MaximumLength = (uint16_t)cbNeeded;
+            pNtName->Buffer        = RTUtf16Alloc(cbNeeded);
+            if (pNtName->Buffer)
+            {
+                memcpy(pNtName->Buffer, pUniStrBuf->Buffer, pUniStrBuf->Length);
+                pNtName->Buffer[pUniStrBuf->Length / sizeof(RTUTF16)] = '\0';
+                rc = VINF_SUCCESS;
+            }
+            else
+                rc = VERR_NO_UTF16_MEMORY;
+        }
+        else
+            rc = VERR_FILENAME_TOO_LONG;
+    }
+    else
+        rc = RTErrConvertFromNtStatus(rcNt);
+    RTMemTmpFree(pUniStrBuf);
+    return rc;
+}
+
+static int rtNtPathRelativeToAbs(struct _UNICODE_STRING *pNtName, HANDLE *phRootDir)
+{
+    int rc;
+    if (pNtName->Length == 0)
+    {
+        RTUtf16Free(pNtName->Buffer);
+        rc = RTNtPathFromHandle(pNtName, *phRootDir, pNtName->Length / sizeof(RTUTF16) + 2);
+        if (RT_SUCCESS(rc))
+        {
+            *phRootDir = NULL;
+            return VINF_SUCCESS;
+        }
+    }
+    else
+    {
+
+        UNICODE_STRING RootDir;
+        size_t const   cwcAppend = pNtName->Length / sizeof(RTUTF16);
+        rc = RTNtPathFromHandle(&RootDir, *phRootDir, cwcAppend + 2);
+        if (RT_SUCCESS(rc))
+        {
+            size_t cwcRoot = RootDir.Length / sizeof(RTUTF16);
+            if (RootDir.Buffer[cwcRoot - 1] != '\\')
+                RootDir.Buffer[cwcRoot++] = '\\';
+            memcpy(&RootDir.Buffer[cwcRoot], pNtName->Buffer, cwcAppend * sizeof(RTUTF16));
+            RTUtf16Free(pNtName->Buffer);
+            pNtName->Length        = (uint16_t)((cwcRoot + cwcAppend) * sizeof(RTUTF16));
+            pNtName->MaximumLength = RootDir.MaximumLength;
+            pNtName->Buffer        = RootDir.Buffer;
+
+            *phRootDir = NULL;
+            return VINF_SUCCESS;
+        }
+        RTUtf16Free(pNtName->Buffer);
+    }
+    pNtName->Length        = 0;
+    pNtName->MaximumLength = 0;
+    pNtName->Buffer        = NULL;
+    return rc;
+}
+
+
+/**
+ * Rewinds the path back to the start of the previous component.
+ *
+ * Will preserve root slash.
+ *
+ * @returns Pointer to character after the start-of-component slash, or
+ *          pwszStart.
+ * @param   pwcEnd              The current end of the path.
+ * @param   pwszStart           The start of the path.
+ */
+static PRTUTF16 rtNtPathGetPrevComponent(PRTUTF16 pwcEnd, PRTUTF16 pwszStart)
+{
+    if ((uintptr_t)pwcEnd > (uintptr_t)pwszStart)
+    {
+        RTUTF16 wc = pwcEnd[-1];
+        if (   (wc == '\\' || wc == '/')
+            && (uintptr_t)(pwcEnd - pwszStart) != 1)
+            pwcEnd--;
+
+        while (   (uintptr_t)pwcEnd > (uintptr_t)pwszStart
+               && (wc = pwcEnd[-1]) != '\\'
+               && (wc = pwcEnd[-1]) != '/')
+            pwcEnd--;
+    }
+    return pwcEnd;
+}
+
+
+/**
+ * Converts a relative windows-style path to relative NT format and encoding.
+ *
+ * @returns IPRT status code.
+ * @param   pNtName             Where to return the NT name.  Free using
+ *                              rtTNtPathToNative with phRootDir set to NULL.
+ * @param   phRootDir           On input, the handle to the directory the path
+ *                              is relative to.  On output, the handle to
+ *                              specify as root directory in the object
+ *                              attributes when accessing the path.  If
+ *                              enmAscent is kRTNtPathRelativeAscent_Allow, it
+ *                              may have been set to NULL.
+ * @param   pszPath             The relative UTF-8 path.
+ * @param   enmAscent           How to handle ascent.
+ * @param   fMustReturnAbsolute Must convert to an absolute path.  This
+ *                              is necessary if the root dir is a NT directory
+ *                              object (e.g. /Devices) since they cannot parse
+ *                              relative paths it seems.
+ */
+RTDECL(int) RTNtPathRelativeFromUtf8(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir, const char *pszPath,
+                                     RTNTPATHRELATIVEASCENT enmAscent, bool fMustReturnAbsolute)
+{
+    size_t cwcMax;
+    int rc = RTStrCalcUtf16LenEx(pszPath, RTSTR_MAX, &cwcMax);
+    if (RT_FAILURE(rc))
+        return rc;
+    if (cwcMax + 2 >= _32K)
+        return VERR_FILENAME_TOO_LONG;
+
+    PRTUTF16 pwszDst;
+    pNtName->Length        = 0;
+    pNtName->MaximumLength = (uint16_t)((cwcMax + 2) * sizeof(RTUTF16));
+    pNtName->Buffer        = pwszDst = RTUtf16Alloc((cwcMax + 2) * sizeof(RTUTF16));
+    if (!pwszDst)
+        return VERR_NO_UTF16_MEMORY;
+
+    PRTUTF16 pwszDstCur  = pwszDst;
+    PRTUTF16 pwszDstComp = pwszDst;
+    for (;;)
+    {
+        RTUNICP uc;
+        rc = RTStrGetCpEx(&pszPath, &uc);
+        if (RT_SUCCESS(rc))
+        {
+            switch (uc)
+            {
+                default:
+                    pwszDstCur = RTUtf16PutCp(pwszDstCur, uc);
+                    break;
+
+                case '\\':
+                case '/':
+                    if (pwszDstCur != pwszDstComp)
+                        pwszDstComp = pwszDstCur = RTUtf16PutCp(pwszDstCur, '\\');
+                    /* else: only one slash between components. */
+                    break;
+
+                case '.':
+                    if (pwszDstCur == pwszDstComp)
+                    {
+                        /*
+                         * Single dot changes nothing.
+                         */
+                        char ch2 = *pszPath;
+                        if (ch2 == '\0')
+                        {
+                            /* Trailing single dot means we need to drop trailing slash. */
+                            if (pwszDstCur != pwszDst)
+                                pwszDstCur--;
+                            *pwszDstCur = '\0';
+                            pNtName->Length = (uint16_t)((uintptr_t)pwszDstCur - (uintptr_t)pwszDst);
+                            if (!fMustReturnAbsolute || *phRootDir == NULL)
+                                return VINF_SUCCESS;
+                            return rtNtPathRelativeToAbs(pNtName, phRootDir);
+                        }
+
+                        if (ch2 == '\\' || ch2 == '/')
+                        {
+                            pszPath++; /* Ignore lone dot followed but another component. */
+                            break;
+                        }
+
+                        /*
+                         * Two dots drops off the last directory component.  This gets complicated
+                         * when we start out without any path and we need to consult enmAscent.
+                         */
+                        if (ch2 == '.')
+                        {
+                            char ch3 = pszPath[1];
+                            if (   ch3 == '\\'
+                                || ch3 == '/'
+                                || ch3 == '\0')
+                            {
+                                /* Drop a path component. */
+                                if (pwszDstComp != pwszDst)
+                                    pwszDstComp = pwszDstCur = rtNtPathGetPrevComponent(pwszDstCur, pwszDst);
+                                /* Hit the start, which is a bit complicated. */
+                                else
+                                    switch (enmAscent)
+                                    {
+                                        case kRTNtPathRelativeAscent_Allow:
+                                            if (*phRootDir != NULL)
+                                            {
+                                                RTUtf16Free(pwszDst);
+                                                rc = RTNtPathFromHandle(pNtName, *phRootDir, cwcMax + 2);
+                                                if (RT_FAILURE(rc))
+                                                    return rc;
+
+                                                *phRootDir = NULL;
+                                                pwszDst    = pNtName->Buffer;
+                                                pwszDstCur = &pwszDst[pNtName->Length / sizeof(RTUTF16)];
+                                                if (   pwszDst != pwszDstCur
+                                                    && pwszDstCur[-1] != '\\'
+                                                    && pwszDstCur[-1] != '/')
+                                                    *pwszDstCur++ = '\\';
+                                                pwszDstComp = pwszDstCur = rtNtPathGetPrevComponent(pwszDstCur, pwszDst);
+                                            }
+                                            /* else: ignore attempt to ascend beyond the NT root (won't get here). */
+                                            break;
+
+                                        case kRTNtPathRelativeAscent_Ignore:
+                                            /* nothing to do here */
+                                            break;
+
+                                        default:
+                                        case kRTNtPathRelativeAscent_Fail:
+                                            RTUtf16Free(pwszDst);
+                                            return VERR_PATH_NOT_FOUND;
+                                    }
+
+                                if (ch3 == '\0')
+                                {
+                                    *pwszDstCur = '\0';
+                                    pNtName->Length = (uint16_t)((uintptr_t)pwszDstCur - (uintptr_t)pwszDst);
+                                    if (!fMustReturnAbsolute || *phRootDir == NULL)
+                                        return VINF_SUCCESS;
+                                    return rtNtPathRelativeToAbs(pNtName, phRootDir);
+                                }
+                                pszPath += 2;
+                                break;
+                            }
+                        }
+                    }
+
+                    /* Neither '.' nor '..'. */
+                    pwszDstCur = RTUtf16PutCp(pwszDstCur, '.');
+                    break;
+
+                case '\0':
+                    *pwszDstCur = '\0';
+                    pNtName->Length = (uint16_t)((uintptr_t)pwszDstCur - (uintptr_t)pwszDst);
+                    if (!fMustReturnAbsolute || *phRootDir == NULL)
+                        return VINF_SUCCESS;
+                    return rtNtPathRelativeToAbs(pNtName, phRootDir);
+            }
+        }
+    }
+}
+
+
+/**
+ * Frees the native path and root handle.
+ *
+ * @param   pNtName             The NT path after a successful rtNtPathToNative
+ *                              call or RTNtPathRelativeFromUtf8.
+ * @param   phRootDir           The root handle variable from rtNtPathToNative,
+ *                              but NOT RTNtPathRelativeFromUtf8.
+ */
+static void rtNtPathFreeNative(struct _UNICODE_STRING *pNtName, PHANDLE phRootDir)
+{
+    RTUtf16Free(pNtName->Buffer);
+    pNtName->Buffer = NULL;
+
+    RT_NOREF_PV(phRootDir); /* never returned by rtNtPathToNative, shouldn't be freed in connection with RTNtPathRelativeFromUtf8 */
+}
+
+
+/**
+ * Frees the native path and root handle.
+ *
+ * @param   pNtName             The NT path after a successful rtNtPathToNative
+ *                              call or RTNtPathRelativeFromUtf8.
+ * @param   phRootDir           The root handle variable from rtNtPathToNative,
+ */
+RTDECL(void) RTNtPathFree(struct _UNICODE_STRING *pNtName, HANDLE *phRootDir)
+{
+    rtNtPathFreeNative(pNtName, phRootDir);
+}
+
+
+/**
+ * Wrapper around NtCreateFile.
+ *
+ * @returns IPRT status code.
+ * @param   pszPath             The UTF-8 path.
+ * @param   fDesiredAccess      See NtCreateFile.
+ * @param   fFileAttribs        See NtCreateFile.
+ * @param   fShareAccess        See NtCreateFile.
+ * @param   fCreateDisposition  See NtCreateFile.
+ * @param   fCreateOptions      See NtCreateFile.
+ * @param   fObjAttribs         The OBJECT_ATTRIBUTES::Attributes value, see
+ *                              NtCreateFile and InitializeObjectAttributes.
+ * @param   phHandle            Where to return the handle.
+ * @param   puAction            Where to return the action taken. Optional.
+ */
+RTDECL(int) RTNtPathOpen(const char *pszPath, ACCESS_MASK fDesiredAccess, ULONG fFileAttribs, ULONG fShareAccess,
+                         ULONG fCreateDisposition, ULONG fCreateOptions, ULONG fObjAttribs,
+                         PHANDLE phHandle, PULONG_PTR puAction)
+{
+    *phHandle = RTNT_INVALID_HANDLE_VALUE;
+
+    HANDLE         hRootDir;
+    UNICODE_STRING NtName;
+    int rc = rtNtPathToNative(&NtName, &hRootDir, pszPath);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE              hFile = RTNT_INVALID_HANDLE_VALUE;
+        IO_STATUS_BLOCK     Ios   = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        OBJECT_ATTRIBUTES   ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, &NtName, fObjAttribs, hRootDir, NULL);
+
+        NTSTATUS rcNt = NtCreateFile(&hFile,
+                                     fDesiredAccess,
+                                     &ObjAttr,
+                                     &Ios,
+                                     NULL /* AllocationSize*/,
+                                     fFileAttribs,
+                                     fShareAccess,
+                                     fCreateDisposition,
+                                     fCreateOptions,
+                                     NULL /*EaBuffer*/,
+                                     0 /*EaLength*/);
+        if (NT_SUCCESS(rcNt))
+        {
+            if (puAction)
+                *puAction = Ios.Information;
+            *phHandle = hFile;
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+        rtNtPathFreeNative(&NtName, &hRootDir);
+    }
+    return rc;
+}
+
+
+/**
+ * Wrapper around NtCreateFile.
+ *
+ * @returns IPRT status code.
+ * @param   pszPath             The UTF-8 path.
+ * @param   fDesiredAccess      See NtCreateFile.
+ * @param   fShareAccess        See NtCreateFile.
+ * @param   fCreateOptions      See NtCreateFile.
+ * @param   fObjAttribs         The OBJECT_ATTRIBUTES::Attributes value, see
+ *                              NtCreateFile and InitializeObjectAttributes.
+ * @param   phHandle            Where to return the handle.
+ * @param   pfObjDir            If not NULL, the variable pointed to will be set
+ *                              to @c true if we opened an object directory and
+ *                              @c false if we opened an directory file (normal
+ *                              directory).
+ */
+RTDECL(int) RTNtPathOpenDir(const char *pszPath, ACCESS_MASK fDesiredAccess, ULONG fShareAccess, ULONG fCreateOptions,
+                            ULONG fObjAttribs, PHANDLE phHandle, bool *pfObjDir)
+{
+    *phHandle = RTNT_INVALID_HANDLE_VALUE;
+
+    HANDLE         hRootDir;
+    UNICODE_STRING NtName;
+    int rc = rtNtPathToNative(&NtName, &hRootDir, pszPath);
+    if (RT_SUCCESS(rc))
+    {
+        if (pfObjDir)
+        {
+            *pfObjDir = false;
+#ifdef IPRT_WITH_NT_PATH_PASSTHRU
+            if (   !RTPATH_IS_SLASH(pszPath[0])
+                || !RTPATH_IS_SLASH(pszPath[1])
+                || pszPath[2] != ':'
+                || pszPath[3] != 'i'
+                || pszPath[4] != 'p'
+                || pszPath[5] != 'r'
+                || pszPath[6] != 't'
+                || pszPath[7] != 'n'
+                || pszPath[8] != 't'
+                || pszPath[9] != ':'
+                || !RTPATH_IS_SLASH(pszPath[10]) )
+#endif
+                pfObjDir = NULL;
+        }
+        rc = RTNtPathOpenDirEx(hRootDir, &NtName, fDesiredAccess, fShareAccess, fCreateOptions, fObjAttribs, phHandle, pfObjDir);
+        rtNtPathFreeNative(&NtName, &hRootDir);
+    }
+    return rc;
+}
+
+
+
+/**
+ * Wrapper around NtCreateFile, extended version.
+ *
+ * @returns IPRT status code.
+ * @param   hRootDir            The root director the path is relative to.  NULL
+ *                              if none.
+ * @param   pNtName             The NT path.
+ * @param   fDesiredAccess      See NtCreateFile.
+ * @param   fShareAccess        See NtCreateFile.
+ * @param   fCreateOptions      See NtCreateFile.
+ * @param   fObjAttribs         The OBJECT_ATTRIBUTES::Attributes value, see
+ *                              NtCreateFile and InitializeObjectAttributes.
+ * @param   phHandle            Where to return the handle.
+ * @param   pfObjDir            If not NULL, the variable pointed to will be set
+ *                              to @c true if we opened an object directory and
+ *                              @c false if we opened an directory file (normal
+ *                              directory).
+ */
+RTDECL(int) RTNtPathOpenDirEx(HANDLE hRootDir, struct _UNICODE_STRING *pNtName, ACCESS_MASK fDesiredAccess, ULONG fShareAccess,
+                              ULONG fCreateOptions, ULONG fObjAttribs, PHANDLE phHandle, bool *pfObjDir)
+{
+    *phHandle = RTNT_INVALID_HANDLE_VALUE;
+
+    HANDLE              hFile = RTNT_INVALID_HANDLE_VALUE;
+    IO_STATUS_BLOCK     Ios   = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    OBJECT_ATTRIBUTES   ObjAttr;
+    InitializeObjectAttributes(&ObjAttr, pNtName, fObjAttribs, hRootDir, NULL);
+
+    NTSTATUS rcNt = NtCreateFile(&hFile,
+                                 fDesiredAccess,
+                                 &ObjAttr,
+                                 &Ios,
+                                 NULL /* AllocationSize*/,
+                                 FILE_ATTRIBUTE_NORMAL,
+                                 fShareAccess,
+                                 FILE_OPEN,
+                                 fCreateOptions,
+                                 NULL /*EaBuffer*/,
+                                 0 /*EaLength*/);
+    if (NT_SUCCESS(rcNt))
+    {
+        if (pfObjDir)
+            *pfObjDir = false;
+        *phHandle = hFile;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Try add a slash in case this is a device object with a file system attached.
+     */
+    if (   rcNt == STATUS_INVALID_PARAMETER
+        && pNtName->Length < _64K - 4
+        && (   pNtName->Length == 0
+            || pNtName->Buffer[pNtName->Length / sizeof(RTUTF16)] != '\\') )
+    {
+        UNICODE_STRING NtTmp;
+        NtTmp.Length        = pNtName->Length + 2;
+        NtTmp.MaximumLength = NtTmp.Length + 2;
+        NtTmp.Buffer        = (PRTUTF16)RTMemTmpAlloc(NtTmp.MaximumLength);
+        if (NtTmp.Buffer)
+        {
+            memcpy(NtTmp.Buffer, pNtName->Buffer, pNtName->Length);
+            NtTmp.Buffer[pNtName->Length / sizeof(RTUTF16)] = '\\';
+            NtTmp.Buffer[pNtName->Length / sizeof(RTUTF16) + 1] = '\0';
+
+            hFile = RTNT_INVALID_HANDLE_VALUE;
+            Ios.Status = -1;
+            Ios.Information = 0;
+            ObjAttr.ObjectName = &NtTmp;
+
+            rcNt = NtCreateFile(&hFile,
+                                fDesiredAccess,
+                                &ObjAttr,
+                                &Ios,
+                                NULL /* AllocationSize*/,
+                                FILE_ATTRIBUTE_NORMAL,
+                                fShareAccess,
+                                FILE_OPEN,
+                                fCreateOptions,
+                                NULL /*EaBuffer*/,
+                                0 /*EaLength*/);
+            RTMemTmpFree(NtTmp.Buffer);
+            if (NT_SUCCESS(rcNt))
+            {
+                if (pfObjDir)
+                    *pfObjDir = false;
+                *phHandle = hFile;
+                return VINF_SUCCESS;
+            }
+            ObjAttr.ObjectName = pNtName;
+        }
+    }
+
+    /*
+     * Try open it as a directory object if it makes sense.
+     */
+    if (   pfObjDir
+        && (   rcNt == STATUS_OBJECT_NAME_INVALID
+            || rcNt == STATUS_OBJECT_TYPE_MISMATCH ))
+    {
+        /* Strip trailing slash. */
+        struct _UNICODE_STRING NtName2 = *pNtName;
+        if (   NtName2.Length > 2
+            && RTPATH_IS_SLASH(NtName2.Buffer[(NtName2.Length / 2) - 1]))
+            NtName2.Length -= 2;
+        ObjAttr.ObjectName = &NtName2;
+
+        /* Rought conversion of the access flags. */
+        ULONG fObjDesiredAccess = 0;
+        if (   (fDesiredAccess & GENERIC_ALL)
+            || (fDesiredAccess & STANDARD_RIGHTS_ALL) == STANDARD_RIGHTS_ALL)
+            fObjDesiredAccess = DIRECTORY_ALL_ACCESS;
+        else
+        {
+            if (fDesiredAccess & (GENERIC_WRITE | STANDARD_RIGHTS_WRITE | FILE_WRITE_DATA))
+                fObjDesiredAccess |= DIRECTORY_CREATE_OBJECT | DIRECTORY_CREATE_OBJECT | DIRECTORY_CREATE_SUBDIRECTORY;
+
+            if (   (fDesiredAccess & (GENERIC_READ | STANDARD_RIGHTS_READ | FILE_LIST_DIRECTORY))
+                || !fObjDesiredAccess)
+                fObjDesiredAccess |= DIRECTORY_QUERY;
+
+            if (fDesiredAccess & FILE_TRAVERSE)
+                fObjDesiredAccess |= DIRECTORY_TRAVERSE;
+        }
+
+        rcNt = NtOpenDirectoryObject(&hFile, fObjDesiredAccess, &ObjAttr);
+        if (NT_SUCCESS(rcNt))
+        {
+            *pfObjDir = true;
+            *phHandle = hFile;
+            return VINF_SUCCESS;
+        }
+    }
+
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
+
+
+/**
+ * Closes an handled open by rtNtPathOpen.
+ *
+ * @returns IPRT status code
+ * @param   hHandle             The handle value.
+ */
+RTDECL(int) RTNtPathClose(HANDLE hHandle)
+{
+    NTSTATUS rcNt = NtClose(hHandle);
+    if (NT_SUCCESS(rcNt))
+        return VINF_SUCCESS;
+    return RTErrConvertFromNtStatus(rcNt);
+}
+
diff --git a/src/VBox/Runtime/r3/nt/time-nt.cpp b/src/VBox/Runtime/r3/nt/time-nt.cpp
new file mode 100644
index 00000000..f60250e6
--- /dev/null
+++ b/src/VBox/Runtime/r3/nt/time-nt.cpp
@@ -0,0 +1,228 @@
+/* $Id: time-nt.cpp $ */
+/** @file
+ * IPRT - Time, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#include "internal-r3-nt.h"
+
+#include <iprt/time.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/ldr.h>
+#include <iprt/uint128.h>
+#include "internal/time.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Whether we've tried to resolve g_pfnRtlGetSystemTimePrecise or not. */
+static bool                         g_fInitialized = false;
+/** Pointer to RtlGetSystemTimePrecise, added in 6.2 (windows 8).   */
+static PFNRTLGETSYSTEMTIMEPRECISE   g_pfnRtlGetSystemTimePrecise = NULL;
+
+
+/**
+ * Initializes globals.
+ */
+static void rtTimeNtInitialize(void)
+{
+    /*
+     * Make sure we don't recurse here when calling into RTLdr.
+     */
+    if (ASMAtomicCmpXchgBool(&g_fInitialized, true, false))
+    {
+        void *pvFunc = RTLdrGetSystemSymbol("ntdll.dll", "RtlGetSystemTimePrecise");
+        if (pvFunc)
+            ASMAtomicWritePtr((void * volatile *)&g_pfnRtlGetSystemTimePrecise, pvFunc);
+        ASMCompilerBarrier();
+    }
+}
+
+
+static uint64_t rtTimeGetSystemNanoTS(void)
+{
+    if (RT_UNLIKELY(!g_fInitialized))
+        rtTimeNtInitialize();
+
+    KUSER_SHARED_DATA volatile *pUserSharedData = (KUSER_SHARED_DATA volatile *)MM_SHARED_USER_DATA_VA;
+
+#if 1
+    /*
+     * If there is precise time, get the precise system time and calculate the
+     * interrupt time from it.  (Microsoft doesn't expose interrupt time to user
+     * application, which is very unfortunate as there are a lot place where
+     * monotonic time is applicable but developer is "forced" to use wall clock.)
+     */
+    if (g_pfnRtlGetSystemTimePrecise)
+    {
+        for (;;)
+        {
+            uint64_t uUpdateLockBefore;
+            while ((uUpdateLockBefore = pUserSharedData->TimeUpdateLock) & 1)
+                ASMNopPause();
+
+            uint64_t        uInterruptTime                  = *(uint64_t volatile *)&pUserSharedData->InterruptTime;
+            uint64_t        uBaselineInterruptTimeQpc       = pUserSharedData->BaselineInterruptTimeQpc;
+            uint64_t        uQpcInterruptTimeIncrement      = pUserSharedData->QpcInterruptTimeIncrement;
+            uint8_t         uQpcInterruptTimeIncrementShift = pUserSharedData->QpcInterruptTimeIncrementShift;
+            LARGE_INTEGER   QpcValue;
+            RtlQueryPerformanceCounter(&QpcValue);
+
+            if (pUserSharedData->TimeUpdateLock == uUpdateLockBefore)
+            {
+                uint64_t uQpcValue = QpcValue.QuadPart;
+                if (uQpcValue <= uBaselineInterruptTimeQpc)
+                    return uInterruptTime * 100;
+
+                /* Calc QPC delta since base line. */
+                uQpcValue -= uBaselineInterruptTimeQpc;
+                uQpcValue--;
+
+                /* Multiply by 10 million. */
+                uQpcValue *= UINT32_C(10000000);
+
+                /* Multiply by QPC interrupt time increment value. */
+                RTUINT128U Tmp128;
+                RTUInt128MulU64ByU64(&Tmp128, uQpcValue, uQpcInterruptTimeIncrement);
+
+                /* Shift the upper 64 bits by the increment shift factor. */
+                uint64_t uResult = Tmp128.s.Hi >> uQpcInterruptTimeIncrementShift;
+
+                /* Add to base interrupt time value. */
+                uResult += uInterruptTime;
+
+                /* Convert from NT unit to nano seconds. */
+                return uResult * 100;
+            }
+
+            ASMNopPause();
+        }
+    }
+#endif
+
+    /*
+     * Just read interrupt time.
+     */
+#if ARCH_BITS >= 64
+    uint64_t uRet = *(uint64_t volatile *)&pUserSharedData->InterruptTime; /* This is what KeQueryInterruptTime does. */
+    uRet *= 100;
+    return uRet;
+#else
+
+    LARGE_INTEGER NtTime;
+    do
+    {
+        NtTime.HighPart = pUserSharedData->InterruptTime.High1Time;
+        NtTime.LowPart  = pUserSharedData->InterruptTime.LowPart;
+    } while (pUserSharedData->InterruptTime.High2Time != NtTime.HighPart);
+
+    return (uint64_t)NtTime.QuadPart * 100;
+#endif
+}
+
+
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
+
+RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
+{
+    /*
+     * Get the precise time if possible.
+     */
+    if (RT_UNLIKELY(!g_fInitialized))
+        rtTimeNtInitialize();
+    if (g_pfnRtlGetSystemTimePrecise != NULL)
+        return RTTimeSpecSetNtTime(pTime, g_pfnRtlGetSystemTimePrecise());
+
+    /*
+     * Just read system time.
+     */
+    KUSER_SHARED_DATA volatile *pUserSharedData = (KUSER_SHARED_DATA volatile *)MM_SHARED_USER_DATA_VA;
+#ifdef RT_ARCH_AMD64
+    uint64_t uRet = *(uint64_t volatile *)&pUserSharedData->SystemTime; /* This is what KeQuerySystemTime does. */
+    return RTTimeSpecSetNtTime(pTime, uRet);
+#else
+
+    LARGE_INTEGER NtTime;
+    do
+    {
+        NtTime.HighPart = pUserSharedData->SystemTime.High1Time;
+        NtTime.LowPart  = pUserSharedData->SystemTime.LowPart;
+    } while (pUserSharedData->SystemTime.High2Time != NtTime.HighPart);
+    return RTTimeSpecSetNtTime(pTime, NtTime.QuadPart);
+#endif
+}
+
+
+RTDECL(PRTTIMESPEC) RTTimeLocalNow(PRTTIMESPEC pTime)
+{
+    return RTTimeSpecAddNano(RTTimeNow(pTime), RTTimeLocalDeltaNano());
+}
+
+
+RTDECL(int64_t) RTTimeLocalDeltaNano(void)
+{
+    /*
+     * UTC = local + TimeZoneBias; The bias is given in NT units.
+     */
+    KUSER_SHARED_DATA volatile *pUserSharedData = (KUSER_SHARED_DATA volatile *)MM_SHARED_USER_DATA_VA;
+    LARGE_INTEGER               Delta;
+#if ARCH_BITS == 64
+    Delta.QuadPart = *(int64_t volatile *)&pUserSharedData->TimeZoneBias;
+#else
+    do
+    {
+        Delta.HighPart = pUserSharedData->TimeZoneBias.High1Time;
+        Delta.LowPart  = pUserSharedData->TimeZoneBias.LowPart;
+    } while (pUserSharedData->TimeZoneBias.High2Time != Delta.HighPart);
+#endif
+    return Delta.QuadPart * -100;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/Makefile.kup b/src/VBox/Runtime/r3/os2/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/Makefile.kup
diff --git a/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp b/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp
new file mode 100644
index 00000000..fded291b
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp
@@ -0,0 +1,121 @@
+/* $Id: RTTimeSet-os2.cpp $ */
+/** @file
+ * IPRT - RTTimeSet, OS/2.
+ */
+
+/*
+ * Contributed by knut st. osmundsen.
+ *
+ * Copyright (C) 2018-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ * --------------------------------------------------------------------
+ *
+ * Copyright (c) 2018 knut st. osmundsen <bird-src-spam@anduin.net>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define INCL_DOSDATETIME
+#define INCL_DOSERRORS
+#include <os2.h>
+
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+
+RTDECL(int) RTTimeSet(PCRTTIMESPEC pTime)
+{
+    /*
+     * Convert to local time and explode it, keeping the distance
+     * between UTC and local.
+     */
+    int64_t    cNsLocalDelta = RTTimeLocalDeltaNanoFor(pTime);
+    RTTIMESPEC TimeLocal     = *pTime;
+    RTTIME     Exploded;
+    if (RTTimeExplode(&Exploded, RTTimeSpecAddNano(&TimeLocal, cNsLocalDelta)))
+    {
+        /*
+         * Fill in the OS/2 structure and make the call.
+         */
+        DATETIME DateTime;
+        DateTime.hours      = Exploded.u8Hour;
+        DateTime.minutes    = Exploded.u8Minute;
+        DateTime.seconds    = Exploded.u8Second;
+        DateTime.hundredths = (uint8_t)(Exploded.u32Nanosecond / (RT_NS_1SEC_64 / 100));
+        DateTime.day        = Exploded.u8MonthDay;
+        DateTime.month      = Exploded.u8Month;
+        DateTime.year       = (uint16_t)Exploded.i32Year;
+        DateTime.weekday    = Exploded.u8WeekDay;
+
+        /* Minutes from UTC.  http://www.edm2.com/os2api/Dos/DosSetDateTime.html says
+           that timezones west of UTC should have a positive value.  The kernel fails
+           the call if we're more than +/-780 min (13h) distant, so clamp it in
+           case of bogus TZ values. */
+        DateTime.timezone   = (int16_t)(-cNsLocalDelta / (int64_t)RT_NS_1MIN);
+        if (DateTime.timezone > 780)
+            DateTime.timezone = 780;
+        else if (DateTime.timezone < -780)
+            DateTime.timezone = -780;
+
+        APIRET rc = DosSetDateTime(&DateTime);
+        if (rc == NO_ERROR)
+            return VINF_SUCCESS;
+        AssertMsgFailed(("rc=%u\n", rc));
+        return RTErrConvertFromOS2(rc);
+    }
+    return VERR_INVALID_PARAMETER;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/filelock-os2.cpp b/src/VBox/Runtime/r3/os2/filelock-os2.cpp
new file mode 100644
index 00000000..9fb93078
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/filelock-os2.cpp
@@ -0,0 +1,186 @@
+/* $Id: filelock-os2.cpp $ */
+/** @file
+ * IPRT - File Locking, OS/2.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/fcntl.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include <iprt/file.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+
+
+
+
+RTR3DECL(int)  RTFileLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    Assert(RTFILE_LOCK_WRITE);
+    fl.l_type   = (fLock & RTFILE_LOCK_WRITE) ? F_WRLCK : F_RDLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    Assert(RTFILE_LOCK_WAIT);
+    if (fcntl(RTFileToNative(File), (fLock & RTFILE_LOCK_WAIT) ? F_SETLKW : F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+
+    int iErr = errno;
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
+
+RTR3DECL(int)  RTFileChangeLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    /** @todo copied from ../win/fileio-win.cpp for now but a proper solution
+     * would probably be to modify kLIBC so that __fcntl_locking() first
+     * assumes a change lock request is made (e.g. the same region was
+     * previously F_RDLCK'ed and now needs to be F_WRLCK'ed or vice versa) and
+     * tries to use atomic locking, and only if it fails, it does the regular
+     * lock procedure. The alternative is to use DosSetFileLocks directly here
+     * which basically means copy-pasting the __fcntl_locking() source
+     * code :) Note that the first attempt to call RTFileLock() below assumes
+     * that kLIBC is patched as described above one day and gives it a chance;
+     * on failure, we fall back to the Win-like unlock-then-lock approach. */
+
+    int rc = RTFileLock(File, fLock, offLock, cbLock);
+    if (RT_FAILURE(rc) && rc != VERR_FILE_LOCK_VIOLATION)
+        return rc;
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /* Remove old lock. */
+    rc = RTFileUnlock(File, offLock, cbLock);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Set new lock. */
+    rc = RTFileLock(File, fLock, offLock, cbLock);
+    if (RT_SUCCESS(rc))
+        return rc;
+
+    /* Try to restore old lock. */
+    unsigned fLockOld = (fLock & RTFILE_LOCK_WRITE) ? fLock & ~RTFILE_LOCK_WRITE : fLock | RTFILE_LOCK_WRITE;
+    rc = RTFileLock(File, fLockOld, offLock, cbLock);
+    if (RT_SUCCESS(rc))
+        return VERR_FILE_LOCK_VIOLATION;
+    else
+        return VERR_FILE_LOCK_LOST;
+}
+
+
+RTR3DECL(int)  RTFileUnlock(RTFILE File, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    fl.l_type   = F_UNLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    if (fcntl(RTFileToNative(File), F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+
+    /** @todo check error codes for non existing lock. */
+    int iErr = errno;
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
diff --git a/src/VBox/Runtime/r3/os2/mp-os2.cpp b/src/VBox/Runtime/r3/os2/mp-os2.cpp
new file mode 100644
index 00000000..64ae06a8
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/mp-os2.cpp
@@ -0,0 +1,125 @@
+/* $Id: mp-os2.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, OS/2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define INCL_BASE
+#define INCL_ERRORS
+#include <os2.h>
+#undef RT_MAX
+
+#include <iprt/mp.h>
+#include <iprt/cpuset.h>
+#include <iprt/assert.h>
+
+/** @todo RTMpCpuId() */
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    return idCpu < RTCPUSET_MAX_CPUS ? (int) idCpu : -1;
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    return (unsigned)iCpu < RTCPUSET_MAX_CPUS ? iCpu : NIL_RTCPUID;
+}
+
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    return RTCPUSET_MAX_CPUS;
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    RTCPUSET Set;
+    return RTCpuSetIsMember(RTMpGetSet(&Set), idCpu);
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+    RTCPUID idCpu = RTMpGetCount();
+    RTCpuSetEmpty(pSet);
+    while (idCpu-- > 0)
+        RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    ULONG cCpus = 1;
+    int rc = DosQuerySysInfo(QSV_NUMPROCESSORS, QSV_NUMPROCESSORS, &cCpus, sizeof(cCpus));
+    if (rc || !cCpus)
+        cCpus = 1;
+    return cCpus;
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+    RTCPUSET Set;
+    return RTCpuSetIsMember(RTMpGetOnlineSet(&Set), idCpu);
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    union
+    {
+        uint64_t u64;
+        MPAFFINITY mpaff;
+    } u;
+
+    int rc = DosQueryThreadAffinity(AFNTY_SYSTEM, &u.mpaff);
+    if (rc)
+        u.u64 = 1;
+    return RTCpuSetFromU64(pSet, u.u64);
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+    RTCPUSET Set;
+    RTMpGetOnlineSet(&Set);
+    return RTCpuSetCount(&Set);
+}
+
diff --git a/src/VBox/Runtime/r3/os2/pipe-os2.cpp b/src/VBox/Runtime/r3/os2/pipe-os2.cpp
new file mode 100644
index 00000000..6a4792c5
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/pipe-os2.cpp
@@ -0,0 +1,1083 @@
+/* $Id: pipe-os2.cpp $ */
+/** @file
+ * IPRT - Anonymous Pipes, OS/2 Implementation.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define INCL_ERRORS
+#define INCL_DOSSEMAPHORES
+#include <os2.h>
+
+#include <iprt/pipe.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/poll.h>
+#include <iprt/process.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/pipe.h"
+#include "internal/magics.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The pipe buffer size we prefer. */
+#define RTPIPE_OS2_SIZE     _32K
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct RTPIPEINTERNAL
+{
+    /** Magic value (RTPIPE_MAGIC). */
+    uint32_t            u32Magic;
+    /** The pipe handle. */
+    HPIPE               hPipe;
+    /** Set if this is the read end, clear if it's the write end. */
+    bool                fRead;
+    /** RTPipeFromNative: Leave open. */
+    bool                fLeaveOpen;
+    /** Whether the pipe is in blocking or non-blocking mode. */
+    bool                fBlocking;
+    /** Set if the pipe is broken. */
+    bool                fBrokenPipe;
+    /** Usage counter. */
+    uint32_t            cUsers;
+
+    /** The event semaphore associated with the pipe. */
+    HEV                 hev;
+    /** The handle of the poll set currently polling on this pipe.
+     *  We can only have one poller at the time (lazy bird). */
+    RTPOLLSET           hPollSet;
+    /** Critical section protecting the above members.
+     * (Taking the lazy/simple approach.) */
+    RTCRITSECT          CritSect;
+
+} RTPIPEINTERNAL;
+
+
+/**
+ * Ensures that the pipe has a semaphore associated with it.
+ *
+ * @returns VBox status code.
+ * @param   pThis               The pipe.
+ */
+static int rtPipeOs2EnsureSem(RTPIPEINTERNAL *pThis)
+{
+    if (pThis->hev != NULLHANDLE)
+        return VINF_SUCCESS;
+
+    HEV     hev;
+    APIRET  orc = DosCreateEventSem(NULL, &hev, DC_SEM_SHARED, FALSE);
+    if (orc == NO_ERROR)
+    {
+        orc = DosSetNPipeSem(pThis->hPipe, (HSEM)hev, 1);
+        if (orc == NO_ERROR)
+        {
+            pThis->hev = hev;
+            return VINF_SUCCESS;
+        }
+
+        DosCloseEventSem(hev);
+    }
+    return RTErrConvertFromOS2(orc);
+}
+
+
+RTDECL(int)  RTPipeCreate(PRTPIPE phPipeRead, PRTPIPE phPipeWrite, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipeRead, VERR_INVALID_POINTER);
+    AssertPtrReturn(phPipeWrite, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_C_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Try create and connect a pipe pair.
+     */
+    APIRET  orc;
+    HPIPE   hPipeR;
+    HFILE   hPipeW;
+    int     rc;
+    for (;;)
+    {
+        static volatile uint32_t    g_iNextPipe = 0;
+        char                        szName[128];
+        RTStrPrintf(szName, sizeof(szName), "\\pipe\\iprt-pipe-%u-%u", RTProcSelf(), ASMAtomicIncU32(&g_iNextPipe));
+
+        /*
+         * Create the read end of the pipe.
+         */
+        ULONG fPipeMode = 1 /*instance*/ | NP_TYPE_BYTE | NP_READMODE_BYTE | NP_NOWAIT;
+        ULONG fOpenMode = NP_ACCESS_DUPLEX | NP_WRITEBEHIND;
+        if (fFlags & RTPIPE_C_INHERIT_READ)
+            fOpenMode |= NP_INHERIT;
+        else
+            fOpenMode |= NP_NOINHERIT;
+        orc = DosCreateNPipe((PSZ)szName, &hPipeR, fOpenMode, fPipeMode, RTPIPE_OS2_SIZE, RTPIPE_OS2_SIZE, NP_DEFAULT_WAIT);
+        if (orc == NO_ERROR)
+        {
+            orc = DosConnectNPipe(hPipeR);
+            if (orc == ERROR_PIPE_NOT_CONNECTED || orc == NO_ERROR)
+            {
+                /*
+                 * Connect to the pipe (the write end), attach sem below.
+                 */
+                ULONG ulAction = 0;
+                ULONG fOpenW   = OPEN_ACTION_FAIL_IF_NEW | OPEN_ACTION_OPEN_IF_EXISTS;
+                ULONG fModeW   = OPEN_ACCESS_WRITEONLY | OPEN_SHARE_DENYNONE | OPEN_FLAGS_FAIL_ON_ERROR;
+                if (!(fFlags & RTPIPE_C_INHERIT_WRITE))
+                    fModeW |= OPEN_FLAGS_NOINHERIT;
+                orc = DosOpen((PSZ)szName, &hPipeW, &ulAction, 0 /*cbFile*/, FILE_NORMAL,
+                              fOpenW, fModeW, NULL /*peaop2*/);
+                if (orc == NO_ERROR)
+                    break;
+            }
+            DosClose(hPipeR);
+        }
+        if (   orc != ERROR_PIPE_BUSY     /* already exist - compatible */
+            && orc != ERROR_ACCESS_DENIED /* already exist - incompatible (?) */)
+            return RTErrConvertFromOS2(orc);
+        /* else: try again with a new name */
+    }
+
+    /*
+     * Create the two handles.
+     */
+    RTPIPEINTERNAL *pThisR = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+    if (pThisR)
+    {
+        RTPIPEINTERNAL *pThisW = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+        if (pThisW)
+        {
+            /* Crit sects. */
+            rc = RTCritSectInit(&pThisR->CritSect);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTCritSectInit(&pThisW->CritSect);
+                if (RT_SUCCESS(rc))
+                {
+                    /* Initialize the structures. */
+                    pThisR->u32Magic        = RTPIPE_MAGIC;
+                    pThisW->u32Magic        = RTPIPE_MAGIC;
+                    pThisR->hPipe           = hPipeR;
+                    pThisW->hPipe           = hPipeW;
+                    pThisR->hev             = NULLHANDLE;
+                    pThisW->hev             = NULLHANDLE;
+                    pThisR->fRead           = true;
+                    pThisW->fRead           = false;
+                    pThisR->fLeaveOpen      = false;
+                    pThisW->fLeaveOpen      = false;
+                    pThisR->fBlocking       = false;
+                    pThisW->fBlocking       = true;
+                    //pThisR->fBrokenPipe     = false;
+                    //pThisW->fBrokenPipe     = false;
+                    //pThisR->cUsers          = 0;
+                    //pThisW->cUsers          = 0;
+                    pThisR->hPollSet        = NIL_RTPOLLSET;
+                    pThisW->hPollSet        = NIL_RTPOLLSET;
+
+                    *phPipeRead  = pThisR;
+                    *phPipeWrite = pThisW;
+                    return VINF_SUCCESS;
+                }
+
+                RTCritSectDelete(&pThisR->CritSect);
+            }
+            RTMemFree(pThisW);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+        RTMemFree(pThisR);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    /* Don't call DosDisConnectNPipe! */
+    DosClose(hPipeW);
+    DosClose(hPipeR);
+    return rc;
+}
+
+
+RTDECL(int)  RTPipeCloseEx(RTPIPE hPipe, bool fLeaveOpen)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    if (pThis == NIL_RTPIPE)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTPIPE_MAGIC, RTPIPE_MAGIC), VERR_INVALID_HANDLE);
+    RTCritSectEnter(&pThis->CritSect);
+    Assert(pThis->cUsers == 0);
+
+    /* Don't call DosDisConnectNPipe! */
+    if (!fLeaveOpen && !pThis->fLeaveOpen)
+        DosClose(pThis->hPipe);
+    pThis->hPipe = (HPIPE)-1;
+
+    if (pThis->hev != NULLHANDLE)
+    {
+        DosCloseEventSem(pThis->hev);
+        pThis->hev = NULLHANDLE;
+    }
+
+    RTCritSectLeave(&pThis->CritSect);
+    RTCritSectDelete(&pThis->CritSect);
+
+    RTMemFree(pThis);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTPipeClose(RTPIPE hPipe)
+{
+    return RTPipeCloseEx(hPipe, false /*fLeaveOpen*/);
+}
+
+
+RTDECL(int)  RTPipeFromNative(PRTPIPE phPipe, RTHCINTPTR hNativePipe, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipe, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_N_VALID_MASK_FN), VERR_INVALID_PARAMETER);
+    AssertReturn(!!(fFlags & RTPIPE_N_READ) != !!(fFlags & RTPIPE_N_WRITE), VERR_INVALID_PARAMETER);
+
+    /*
+     * Get and validate the pipe handle info.
+     */
+    HPIPE hNative = (HPIPE)hNativePipe;
+    ULONG ulType  = 0;
+    ULONG ulAttr  = 0;
+    APIRET orc = DosQueryHType(hNative, &ulType, &ulAttr);
+    AssertMsgReturn(orc == NO_ERROR, ("%d\n", orc), RTErrConvertFromOS2(orc));
+    AssertReturn((ulType & 0x7) == HANDTYPE_PIPE, VERR_INVALID_HANDLE);
+
+#if 0
+    union
+    {
+        PIPEINFO    PipeInfo;
+        uint8_t     abPadding[sizeof(PIPEINFO) + 127];
+    } Buf;
+    orc = DosQueryNPipeInfo(hNative, 1, &Buf, sizeof(Buf));
+    if (orc != NO_ERROR)
+    {
+        /* Sorry, anonymous pips are not supported. */
+        AssertMsgFailed(("%d\n", orc));
+        return VERR_INVALID_HANDLE;
+    }
+    AssertReturn(Buf.PipeInfo.cbMaxInst == 1, VERR_INVALID_HANDLE);
+#endif
+
+    ULONG fPipeState = 0;
+    orc = DosQueryNPHState(hNative, &fPipeState);
+    if (orc != NO_ERROR)
+    {
+        /* Sorry, anonymous pips are not supported. */
+        AssertMsgFailed(("%d\n", orc));
+        return VERR_INVALID_HANDLE;
+    }
+    AssertReturn(!(fPipeState & NP_TYPE_MESSAGE), VERR_INVALID_HANDLE);
+    AssertReturn(!(fPipeState & NP_READMODE_MESSAGE), VERR_INVALID_HANDLE);
+    AssertReturn((fPipeState & 0xff) == 1, VERR_INVALID_HANDLE);
+
+    ULONG fFileState = 0;
+    orc = DosQueryFHState(hNative, &fFileState);
+    AssertMsgReturn(orc == NO_ERROR, ("%d\n", orc), VERR_INVALID_HANDLE);
+    AssertMsgReturn(   (fFileState & 0x3) == (fFlags & RTPIPE_N_READ ? OPEN_ACCESS_READONLY : OPEN_ACCESS_WRITEONLY)
+                    || (fFileState & 0x3) == OPEN_ACCESS_READWRITE
+                    , ("%#x\n", fFileState), VERR_INVALID_HANDLE);
+
+    /*
+     * Looks kind of OK. Fix the inherit flag.
+     */
+    orc = DosSetFHState(hNative,   (fFileState & (OPEN_FLAGS_WRITE_THROUGH | OPEN_FLAGS_FAIL_ON_ERROR | OPEN_FLAGS_NO_CACHE))
+                                 | (fFlags & RTPIPE_N_INHERIT ? 0 : OPEN_FLAGS_NOINHERIT));
+    AssertMsgReturn(orc == NO_ERROR, ("%d\n", orc), RTErrConvertFromOS2(orc));
+
+
+    /*
+     * Create a handle so we can try rtPipeQueryInfo on it
+     * and see if we need to duplicate it to make that call work.
+     */
+    RTPIPEINTERNAL *pThis = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+    int rc = RTCritSectInit(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        pThis->u32Magic        = RTPIPE_MAGIC;
+        pThis->hPipe           = hNative;
+        pThis->hev             = NULLHANDLE;
+        pThis->fRead           = RT_BOOL(fFlags & RTPIPE_N_READ);
+        pThis->fLeaveOpen      = RT_BOOL(fFlags & RTPIPE_N_LEAVE_OPEN);
+        pThis->fBlocking       = !(fPipeState & NP_NOWAIT);
+        //pThis->fBrokenPipe     = false;
+        //pThis->cUsers          = 0;
+        pThis->hPollSet        = NIL_RTPOLLSET;
+
+        *phPipe = pThis;
+        return VINF_SUCCESS;
+
+        //RTCritSectDelete(&pThis->CritSect);
+    }
+    RTMemFree(pThis);
+    return rc;
+}
+
+RTDECL(RTHCINTPTR) RTPipeToNative(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, -1);
+
+    return (RTHCINTPTR)pThis->hPipe;
+}
+
+/**
+ * Prepare blocking mode.
+ *
+ * @returns IPRT status code.
+ * @retval  VERR_WRONG_ORDER if simultaneous non-blocking and blocking access is
+ *          attempted.
+ *
+ * @param   pThis               The pipe handle.
+ *
+ * @remarks Caller owns the critical section.
+ */
+static int rtPipeTryBlocking(RTPIPEINTERNAL *pThis)
+{
+    if (!pThis->fBlocking)
+    {
+        if (pThis->cUsers != 0)
+            return VERR_WRONG_ORDER;
+
+        APIRET orc = DosSetNPHState(pThis->hPipe, NP_WAIT | NP_READMODE_BYTE);
+        if (orc != NO_ERROR)
+        {
+            if (orc != ERROR_BROKEN_PIPE && orc != ERROR_PIPE_NOT_CONNECTED)
+                return RTErrConvertFromOS2(orc);
+            pThis->fBrokenPipe = true;
+        }
+        pThis->fBlocking = true;
+    }
+
+    pThis->cUsers++;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Prepare non-blocking mode.
+ *
+ * @returns IPRT status code.
+ * @retval  VERR_WRONG_ORDER if simultaneous non-blocking and blocking access is
+ *          attempted.
+ *
+ * @param   pThis               The pipe handle.
+ */
+static int rtPipeTryNonBlocking(RTPIPEINTERNAL *pThis)
+{
+    if (pThis->fBlocking)
+    {
+        if (pThis->cUsers != 0)
+            return VERR_WRONG_ORDER;
+
+        APIRET orc = DosSetNPHState(pThis->hPipe, NP_NOWAIT | NP_READMODE_BYTE);
+        if (orc != NO_ERROR)
+        {
+            if (orc != ERROR_BROKEN_PIPE && orc != ERROR_PIPE_NOT_CONNECTED)
+                return RTErrConvertFromOS2(orc);
+            pThis->fBrokenPipe = true;
+        }
+        pThis->fBlocking = false;
+    }
+
+    pThis->cUsers++;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks if the read pipe has been broken.
+ *
+ * @returns true if broken, false if no.
+ * @param   pThis               The pipe handle (read).
+ */
+static bool rtPipeOs2IsBroken(RTPIPEINTERNAL *pThis)
+{
+    Assert(pThis->fRead);
+
+#if 0
+    /*
+     * Query it via the semaphore. Not sure how fast this is...
+     */
+    PIPESEMSTATE aStates[3]; RT_ZERO(aStates);
+    APIRET orc = DosQueryNPipeSemState(pThis->hev, &aStates[0], sizeof(aStates));
+    if (orc == NO_ERROR)
+    {
+        if (aStates[0].fStatus == NPSS_CLOSE)
+            return true;
+        if (aStates[0].fStatus == NPSS_RDATA)
+            return false;
+    }
+    AssertMsgFailed(("%d / %d\n", orc, aStates[0].fStatus));
+
+    /*
+     * Fall back / alternative method.
+     */
+#endif
+    ULONG       cbActual = 0;
+    ULONG       ulState  = 0;
+    AVAILDATA   Avail    = { 0, 0 };
+    APIRET orc = DosPeekNPipe(pThis->hPipe, NULL, 0, &cbActual, &Avail, &ulState);
+    if (orc != NO_ERROR)
+    {
+        if (orc != ERROR_PIPE_BUSY)
+            AssertMsgFailed(("%d\n", orc));
+        return false;
+    }
+
+    return ulState != NP_STATE_CONNECTED;
+}
+
+
+RTDECL(int) RTPipeRead(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbRead);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPipeTryNonBlocking(pThis);
+        if (RT_SUCCESS(rc))
+        {
+            RTCritSectLeave(&pThis->CritSect);
+
+            ULONG cbActual = 0;
+            APIRET orc = DosRead(pThis->hPipe, pvBuf, cbToRead, &cbActual);
+            if (orc == NO_ERROR)
+            {
+                if (cbActual || !cbToRead || !rtPipeOs2IsBroken(pThis))
+                    *pcbRead = cbActual;
+                else
+                    rc = VERR_BROKEN_PIPE;
+            }
+            else if (orc == ERROR_NO_DATA)
+            {
+                *pcbRead = 0;
+                rc = VINF_TRY_AGAIN;
+            }
+            else
+                rc = RTErrConvertFromOS2(orc);
+
+            RTCritSectEnter(&pThis->CritSect);
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeReadBlocking(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPipeTryBlocking(pThis);
+        if (RT_SUCCESS(rc))
+        {
+            RTCritSectLeave(&pThis->CritSect);
+
+            size_t cbTotalRead = 0;
+            while (cbToRead > 0)
+            {
+                ULONG  cbActual = 0;
+                APIRET orc = DosRead(pThis->hPipe, pvBuf, cbToRead, &cbActual);
+                if (orc != NO_ERROR)
+                {
+                    rc = RTErrConvertFromOS2(orc);
+                    break;
+                }
+                if (!cbActual && rtPipeOs2IsBroken(pThis))
+                {
+                    rc = VERR_BROKEN_PIPE;
+                    break;
+                }
+
+                /* advance */
+                pvBuf        = (char *)pvBuf + cbActual;
+                cbTotalRead += cbActual;
+                cbToRead    -= cbActual;
+            }
+
+            if (pcbRead)
+            {
+                *pcbRead = cbTotalRead;
+                if (   RT_FAILURE(rc)
+                    && cbTotalRead)
+                    rc = VINF_SUCCESS;
+            }
+
+            RTCritSectEnter(&pThis->CritSect);
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+/**
+ * Gets the available write buffer size of the pipe.
+ *
+ * @returns Number of bytes, 1 on failure.
+ * @param   pThis               The pipe handle.
+ */
+static ULONG rtPipeOs2GetSpace(RTPIPEINTERNAL *pThis)
+{
+    Assert(!pThis->fRead);
+
+#if 0 /* Not sure which is more efficient, neither are really optimal, I fear. */
+    /*
+     * Query via semaphore state.
+     * This will walk the list of active named pipes...
+     */
+    /** @todo Check how hev and hpipe are associated, if complicated, use the
+     *        alternative method below. */
+    PIPESEMSTATE aStates[3]; RT_ZERO(aStates);
+    APIRET orc = DosQueryNPipeSemState((HSEM)pThis->hev, &aStates[0], sizeof(aStates));
+    if (orc == NO_ERROR)
+    {
+        if (aStates[0].fStatus == NPSS_WSPACE)
+            return aStates[0].usAvail;
+        if (aStates[1].fStatus == NPSS_WSPACE)
+            return aStates[1].usAvail;
+        return 0;
+    }
+    AssertMsgFailed(("%d / %d\n", orc, aStates[0].fStatus));
+
+#else
+    /*
+     * Query via the pipe info.
+     * This will have to lookup and store the pipe name.
+     */
+    union
+    {
+        PIPEINFO    PipeInfo;
+        uint8_t     abPadding[sizeof(PIPEINFO) + 127];
+    } Buf;
+    APIRET orc = DosQueryNPipeInfo(pThis->hPipe, 1, &Buf, sizeof(Buf));
+    if (orc == NO_ERROR)
+        return Buf.PipeInfo.cbOut;
+    AssertMsgFailed(("%d\n", orc));
+#endif
+
+    return 1;
+}
+
+
+RTDECL(int) RTPipeWrite(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbWritten);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPipeTryNonBlocking(pThis);
+        if (RT_SUCCESS(rc))
+        {
+            if (cbToWrite > 0)
+            {
+                ULONG  cbActual = 0;
+                APIRET orc = DosWrite(pThis->hPipe, pvBuf, cbToWrite, &cbActual);
+                if (orc == NO_ERROR && cbActual == 0)
+                {
+                    /* Retry with the request adjusted to the available buffer space. */
+                    ULONG cbAvail = rtPipeOs2GetSpace(pThis);
+                    orc = DosWrite(pThis->hPipe, pvBuf, RT_MIN(cbAvail, cbToWrite), &cbActual);
+                }
+
+                if (orc == NO_ERROR)
+                {
+                    *pcbWritten = cbActual;
+                    if (cbActual == 0)
+                        rc = VINF_TRY_AGAIN;
+                }
+                else
+                {
+                    rc = RTErrConvertFromOS2(orc);
+                    if (rc == VERR_PIPE_NOT_CONNECTED)
+                        rc = VERR_BROKEN_PIPE;
+                }
+            }
+            else
+                *pcbWritten = 0;
+
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeWriteBlocking(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+    AssertPtrNull(pcbWritten);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPipeTryBlocking(pThis);
+        if (RT_SUCCESS(rc))
+        {
+            RTCritSectLeave(&pThis->CritSect);
+
+            size_t cbTotalWritten = 0;
+            while (cbToWrite > 0)
+            {
+                ULONG cbActual = 0;
+                APIRET orc = DosWrite(pThis->hPipe, pvBuf, cbToWrite, &cbActual);
+                if (orc != NO_ERROR)
+                {
+                    rc = RTErrConvertFromOS2(orc);
+                    if (rc == VERR_PIPE_NOT_CONNECTED)
+                        rc = VERR_BROKEN_PIPE;
+                    break;
+                }
+                pvBuf           = (char const *)pvBuf + cbActual;
+                cbToWrite      -= cbActual;
+                cbTotalWritten += cbActual;
+            }
+
+            if (pcbWritten)
+            {
+                *pcbWritten = cbTotalWritten;
+                if (   RT_FAILURE(rc)
+                    && cbTotalWritten)
+                    rc = VINF_SUCCESS;
+            }
+
+            RTCritSectEnter(&pThis->CritSect);
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeFlush(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+
+    APIRET orc = DosResetBuffer(pThis->hPipe);
+    if (orc != NO_ERROR)
+    {
+        int rc = RTErrConvertFromOS2(orc);
+        if (rc == VERR_BROKEN_PIPE)
+        {
+            RTCritSectEnter(&pThis->CritSect);
+            pThis->fBrokenPipe = true;
+            RTCritSectLeave(&pThis->CritSect);
+        }
+        return rc;
+    }
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTPipeSelectOne(RTPIPE hPipe, RTMSINTERVAL cMillies)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    uint64_t const StartMsTS = RTTimeMilliTS();
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rc = rtPipeOs2EnsureSem(pThis);
+    if (RT_SUCCESS(rc) && cMillies > 0)
+    {
+        /* Stop polling attempts if we might block. */
+        if (pThis->hPollSet == NIL_RTPOLLSET)
+            pThis->hPollSet = (RTPOLLSET)(uintptr_t)0xbeef0042;
+        else
+            rc = VERR_WRONG_ORDER;
+    }
+    if (RT_SUCCESS(rc))
+    {
+        for (unsigned iLoop = 0;; iLoop++)
+        {
+            /*
+             * Check the handle state.
+             */
+            APIRET orc;
+            if (cMillies > 0)
+            {
+                ULONG ulIgnore;
+                orc = DosResetEventSem(pThis->hev, &ulIgnore);
+                AssertMsg(orc == NO_ERROR || orc == ERROR_ALREADY_RESET, ("%d\n", orc));
+            }
+
+            PIPESEMSTATE aStates[4]; RT_ZERO(aStates);
+            orc = DosQueryNPipeSemState((HSEM)pThis->hev, &aStates[0], sizeof(aStates));
+            if (orc != NO_ERROR)
+            {
+                rc = RTErrConvertFromOS2(orc);
+                break;
+            }
+            int i = 0;
+            if (pThis->fRead)
+                while (aStates[i].fStatus == NPSS_WSPACE)
+                    i++;
+            else
+                while (aStates[i].fStatus == NPSS_RDATA)
+                    i++;
+            if (aStates[i].fStatus == NPSS_CLOSE)
+                break;
+            Assert(aStates[i].fStatus == NPSS_WSPACE || aStates[i].fStatus == NPSS_RDATA || aStates[i].fStatus == NPSS_EOI);
+            if (   aStates[i].fStatus != NPSS_EOI
+                && aStates[i].usAvail > 0)
+                break;
+
+            /*
+             * Check for timeout.
+             */
+            ULONG cMsMaxWait = SEM_INDEFINITE_WAIT;
+            if (cMillies != RT_INDEFINITE_WAIT)
+            {
+                uint64_t cElapsed = RTTimeMilliTS() - StartMsTS;
+                if (cElapsed >= cMillies)
+                {
+                    rc = VERR_TIMEOUT;
+                    break;
+                }
+                cMsMaxWait = cMillies - (uint32_t)cElapsed;
+            }
+
+            /*
+             * Wait.
+             */
+            RTCritSectLeave(&pThis->CritSect);
+            orc = DosWaitEventSem(pThis->hev, cMsMaxWait);
+            RTCritSectEnter(&pThis->CritSect);
+            if (orc != NO_ERROR && orc != ERROR_TIMEOUT && orc != ERROR_SEM_TIMEOUT )
+            {
+                rc = RTErrConvertFromOS2(orc);
+                break;
+            }
+        }
+
+        if (rc == VERR_BROKEN_PIPE)
+            pThis->fBrokenPipe = true;
+        if (cMillies > 0)
+            pThis->hPollSet = NIL_RTPOLLSET;
+    }
+
+    RTCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+
+RTDECL(int) RTPipeQueryReadable(RTPIPE hPipe, size_t *pcbReadable)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_PIPE_NOT_READ);
+    AssertPtrReturn(pcbReadable, VERR_INVALID_POINTER);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    ULONG       cbActual = 0;
+    ULONG       ulState  = 0;
+    AVAILDATA   Avail    = { 0, 0 };
+    APIRET orc = DosPeekNPipe(pThis->hPipe, NULL, 0, &cbActual, &Avail, &ulState);
+    if (orc == NO_ERROR)
+    {
+        if (Avail.cbpipe > 0 || ulState == NP_STATE_CONNECTED)
+            *pcbReadable = Avail.cbpipe;
+        else
+            rc = VERR_PIPE_NOT_CONNECTED; /*??*/
+    }
+    else
+        rc = RTErrConvertFromOS2(orc);
+
+    RTCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+
+RTDECL(int) RTPipeQueryInfo(RTPIPE hPipe, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, 0);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, 0);
+
+    rtPipeFakeQueryInfo(pObjInfo, enmAddAttr, pThis->fRead);
+
+    if (pThis->fRead)
+    {
+        ULONG       cbActual = 0;
+        ULONG       ulState  = 0;
+        AVAILDATA   Avail    = { 0, 0 };
+        APIRET orc = DosPeekNPipe(pThis->hPipe, NULL, 0, &cbActual, &Avail, &ulState);
+        if (orc == NO_ERROR && (Avail.cbpipe > 0 || ulState == NP_STATE_CONNECTED))
+            pObjInfo->cbObject = Avail.cbpipe;
+    }
+    else
+        pObjInfo->cbObject = rtPipeOs2GetSpace(pThis);
+    pObjInfo->cbAllocated = RTPIPE_OS2_SIZE; /** @todo this isn't necessarily true if we didn't create it... but, whatever */
+
+    RTCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+
+int rtPipePollGetHandle(RTPIPE hPipe, uint32_t fEvents, PRTHCINTPTR phNative)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    AssertReturn(!(fEvents & RTPOLL_EVT_READ)  || pThis->fRead,  VERR_INVALID_PARAMETER);
+    AssertReturn(!(fEvents & RTPOLL_EVT_WRITE) || !pThis->fRead, VERR_INVALID_PARAMETER);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtPipeOs2EnsureSem(pThis);
+        if (RT_SUCCESS(rc))
+            *phNative = (RTHCINTPTR)pThis->hev;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+/**
+ * Checks for pending events.
+ *
+ * @returns Event mask or 0.
+ * @param   pThis               The pipe handle.
+ * @param   fEvents             The desired events.
+ * @param   fResetEvtSem        Whether to reset the event semaphore.
+ */
+static uint32_t rtPipePollCheck(RTPIPEINTERNAL *pThis, uint32_t fEvents, bool fResetEvtSem)
+{
+    /*
+     * Reset the event semaphore if we're gonna wait.
+     */
+    APIRET orc;
+    ULONG ulIgnore;
+    if (fResetEvtSem)
+    {
+        orc = DosResetEventSem(pThis->hev, &ulIgnore);
+        AssertMsg(orc == NO_ERROR || orc == ERROR_ALREADY_RESET, ("%d\n", orc));
+    }
+
+    /*
+     * Check for events.
+     */
+    uint32_t fRetEvents = 0;
+    if (pThis->fBrokenPipe)
+        fRetEvents |= RTPOLL_EVT_ERROR;
+    else if (pThis->fRead)
+    {
+        ULONG       cbActual = 0;
+        ULONG       ulState  = 0;
+        AVAILDATA   Avail    = { 0, 0 };
+        orc = DosPeekNPipe(pThis->hPipe, NULL, 0, &cbActual, &Avail, &ulState);
+        if (orc != NO_ERROR)
+        {
+            fRetEvents |= RTPOLL_EVT_ERROR;
+            if (orc == ERROR_BROKEN_PIPE || orc == ERROR_PIPE_NOT_CONNECTED)
+                pThis->fBrokenPipe = true;
+        }
+        else if (Avail.cbpipe > 0)
+            fRetEvents |= RTPOLL_EVT_READ;
+        else if (ulState != NP_STATE_CONNECTED)
+        {
+            fRetEvents |= RTPOLL_EVT_ERROR;
+            pThis->fBrokenPipe = true;
+        }
+    }
+    else
+    {
+        PIPESEMSTATE aStates[4]; RT_ZERO(aStates);
+        orc = DosQueryNPipeSemState((HSEM)pThis->hev, &aStates[0], sizeof(aStates));
+        if (orc == NO_ERROR)
+        {
+            int i = 0;
+            while (aStates[i].fStatus == NPSS_RDATA)
+                i++;
+            if (aStates[i].fStatus == NPSS_CLOSE)
+            {
+                fRetEvents |= RTPOLL_EVT_ERROR;
+                pThis->fBrokenPipe = true;
+            }
+            else if (   aStates[i].fStatus == NPSS_WSPACE
+                     && aStates[i].usAvail > 0)
+                fRetEvents |= RTPOLL_EVT_WRITE;
+        }
+        else
+        {
+            fRetEvents |= RTPOLL_EVT_ERROR;
+            if (orc == ERROR_BROKEN_PIPE || orc == ERROR_PIPE_NOT_CONNECTED)
+                pThis->fBrokenPipe = true;
+        }
+    }
+
+    return fRetEvents & (fEvents | RTPOLL_EVT_ERROR);
+}
+
+
+uint32_t rtPipePollStart(RTPIPE hPipe, RTPOLLSET hPollSet, uint32_t fEvents, bool fFinalEntry, bool fNoWait)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, UINT32_MAX);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, UINT32_MAX);
+
+    /* Check that this is the only current use of this pipe. */
+    uint32_t fRetEvents;
+    if (   pThis->cUsers   == 0
+        || pThis->hPollSet == NIL_RTPOLLSET)
+    {
+        fRetEvents = rtPipePollCheck(pThis, fEvents, fNoWait);
+        if (!fRetEvents && !fNoWait)
+        {
+            /* Mark the set busy while waiting. */
+            pThis->cUsers++;
+            pThis->hPollSet = hPollSet;
+        }
+    }
+    else
+    {
+        AssertFailed();
+        fRetEvents = UINT32_MAX;
+    }
+
+    RTCritSectLeave(&pThis->CritSect);
+    return fRetEvents;
+}
+
+
+uint32_t rtPipePollDone(RTPIPE hPipe, uint32_t fEvents, bool fFinalEntry, bool fHarvestEvents)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, 0);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, 0);
+
+    Assert(pThis->cUsers > 0);
+
+    /* harvest events. */
+    uint32_t fRetEvents = rtPipePollCheck(pThis, fEvents, false);
+
+    /* update counters. */
+    pThis->cUsers--;
+    pThis->hPollSet = NIL_RTPOLLSET;
+
+    RTCritSectLeave(&pThis->CritSect);
+    return fRetEvents;
+}
diff --git a/src/VBox/Runtime/r3/os2/rtProcInitExePath-os2.cpp b/src/VBox/Runtime/r3/os2/rtProcInitExePath-os2.cpp
new file mode 100644
index 00000000..bd5e249a
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/rtProcInitExePath-os2.cpp
@@ -0,0 +1,71 @@
+/* $Id: rtProcInitExePath-os2.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, OS/2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Query the image name from the dynamic linker, convert and return it.
+     */
+    _execname(pszPath, cchPath);
+
+    char const *pszTmp;
+    int rc = rtPathFromNative(&pszTmp, pszPath, NULL);
+    AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchPath, pszPath), rc);
+    if (pszTmp != pszPath)
+    {
+        rc = RTStrCopy(pszPath, cchPath, pszTmp);
+        rtPathFreeIprt(pszTmp, pszPath);
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/sched-os2.cpp b/src/VBox/Runtime/r3/os2/sched-os2.cpp
new file mode 100644
index 00000000..25eb75c3
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/sched-os2.cpp
@@ -0,0 +1,244 @@
+/* $Id: sched-os2.cpp $ */
+/** @file
+ * IPRT - Scheduling, OS/2
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/** @def OS2_SCHED_ENABLED
+ * Enables the priority scheme. */
+#define OS2_SCHED_ENABLED
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#define INCL_BASE
+#define INCL_ERRORS
+#include <os2.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include "internal/sched.h"
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Configuration of one priority.
+ */
+typedef struct
+{
+    /** The priority. */
+    RTPROCPRIORITY  enmPriority;
+    /** The name of this priority. */
+    const char     *pszName;
+    /** Array scheduler attributes corresponding to each of the thread types. */
+    struct
+    {
+        /** For sanity include the array index. */
+        RTTHREADTYPE    enmType;
+        /** The OS/2 priority class. */
+        ULONG           ulClass;
+        /** The OS/2 priority delta. */
+        ULONG           ulDelta;
+    } aTypes[RTTHREADTYPE_END];
+} PROCPRIORITY;
+
+/** Matches any process priority class. */
+#define ANY_PROCESS_PRIORITY_CLASS  (~0U)
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Array of static priority configurations.
+ */
+static const PROCPRIORITY g_aPriorities[] =
+{
+    {
+        RTPROCPRIORITY_FLAT, "Flat",
+        {
+            { RTTHREADTYPE_INVALID,                 ~0, ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_EMULATION,               PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_DEFAULT,                 PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_GUI,                     PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_MAIN_WORKER,             PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_VRDP_IO,                 PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_DEBUGGER,                PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_MSG_PUMP,                PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_IO,                      PRTYC_REGULAR, 0 },
+            { RTTHREADTYPE_TIMER,                   PRTYC_REGULAR, 0 }
+        }
+    },
+    {
+        RTPROCPRIORITY_LOW, "Low",
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       PRTYC_IDLETIME, 0 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       PRTYC_IDLETIME, 0 },
+            { RTTHREADTYPE_EMULATION,               PRTYC_IDLETIME, 0 },
+            { RTTHREADTYPE_DEFAULT,                 PRTYC_IDLETIME, 30 },
+            { RTTHREADTYPE_GUI,                     PRTYC_IDLETIME, 30 },
+            { RTTHREADTYPE_MAIN_WORKER,             PRTYC_IDLETIME, 30 },
+            { RTTHREADTYPE_VRDP_IO,                 PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_DEBUGGER,                PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_MSG_PUMP,                PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_IO,                      PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_TIMER,                   PRTYC_REGULAR,  0 }
+        }
+    },
+    {
+        RTPROCPRIORITY_NORMAL, "Normal",
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       PRTYC_IDLETIME, 30 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       PRTYC_IDLETIME, 31 },
+            { RTTHREADTYPE_EMULATION,               PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_DEFAULT,                 PRTYC_REGULAR,  5 },
+            { RTTHREADTYPE_GUI,                     PRTYC_REGULAR,  10 },
+            { RTTHREADTYPE_MAIN_WORKER,             PRTYC_REGULAR,  12 },
+            { RTTHREADTYPE_VRDP_IO,                 PRTYC_REGULAR,  15 },
+            { RTTHREADTYPE_DEBUGGER,                PRTYC_REGULAR,  20 },
+            { RTTHREADTYPE_MSG_PUMP,                PRTYC_REGULAR,  25 },
+            { RTTHREADTYPE_IO,                      PRTYC_FOREGROUNDSERVER,  5 },
+            { RTTHREADTYPE_TIMER,                   PRTYC_TIMECRITICAL, 0 }
+        }
+    },
+    {
+        RTPROCPRIORITY_HIGH, "High",
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       PRTYC_IDLETIME, 30 },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_EMULATION,               PRTYC_REGULAR,  0 },
+            { RTTHREADTYPE_DEFAULT,                 PRTYC_REGULAR,  15 },
+            { RTTHREADTYPE_GUI,                     PRTYC_REGULAR,  20 },
+            { RTTHREADTYPE_MAIN_WORKER,             PRTYC_REGULAR,  25 },
+            { RTTHREADTYPE_VRDP_IO,                 PRTYC_REGULAR,  30 },
+            { RTTHREADTYPE_DEBUGGER,                PRTYC_TIMECRITICAL, 2 },
+            { RTTHREADTYPE_MSG_PUMP,                PRTYC_TIMECRITICAL, 3 },
+            { RTTHREADTYPE_IO,                      PRTYC_TIMECRITICAL, 4 },
+            { RTTHREADTYPE_TIMER,                   PRTYC_TIMECRITICAL, 5 }
+        }
+    }
+};
+
+/**
+ * The dynamic default priority configuration.
+ *
+ * This can be recalulated at runtime depending on what the
+ * system allow us to do. Presently we don't do this as it's
+ * generally not a bit issue on OS/2 hosts.
+ */
+static PROCPRIORITY g_aDefaultPriority =
+{
+    RTPROCPRIORITY_LOW, "Default",
+    {
+        { RTTHREADTYPE_INVALID,                 ~0 },
+        { RTTHREADTYPE_INFREQUENT_POLLER,       PRTYC_IDLETIME, 30 },
+        { RTTHREADTYPE_MAIN_HEAVY_WORKER,       PRTYC_IDLETIME, 31 },
+        { RTTHREADTYPE_EMULATION,               PRTYC_REGULAR,  0 },
+        { RTTHREADTYPE_DEFAULT,                 PRTYC_REGULAR,  5 },
+        { RTTHREADTYPE_GUI,                     PRTYC_REGULAR,  10 },
+        { RTTHREADTYPE_MAIN_WORKER,             PRTYC_REGULAR,  12 },
+        { RTTHREADTYPE_VRDP_IO,                 PRTYC_REGULAR,  15 },
+        { RTTHREADTYPE_DEBUGGER,                PRTYC_REGULAR,  20 },
+        { RTTHREADTYPE_MSG_PUMP,                PRTYC_REGULAR,  25 },
+        { RTTHREADTYPE_IO,                      PRTYC_FOREGROUNDSERVER, 5 },
+        { RTTHREADTYPE_TIMER,                   PRTYC_TIMECRITICAL, 0 }
+    }
+};
+
+
+/** Pointer to the current priority configuration. */
+static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
+
+
+/**
+ * Calculate the scheduling properties for all the threads in the default
+ * process priority, assuming the current thread have the type enmType.
+ *
+ * @returns iprt status code.
+ * @param   enmType     The thread type to be assumed for the current thread.
+ */
+DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
+{
+    Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
+
+    if (enmPriority == RTPROCPRIORITY_DEFAULT)
+    {
+        g_pProcessPriority = &g_aDefaultPriority;
+        return VINF_SUCCESS;
+    }
+
+    for (size_t i = 0; i < RT_ELEMENTS(g_aPriorities); i++)
+        if (g_aPriorities[i].enmPriority == enmPriority)
+        {
+            g_pProcessPriority = &g_aPriorities[i];
+            return VINF_SUCCESS;
+        }
+
+    AssertFailedReturn(VERR_INTERNAL_ERROR);
+}
+
+
+DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    AssertMsg(g_pProcessPriority && g_pProcessPriority->aTypes[enmType].enmType == enmType,
+              ("enmType=%d entry=%d\n", enmType, g_pProcessPriority->aTypes[enmType].enmType));
+
+#ifdef OS2_SCHED_ENABLED
+    APIRET rc = DosSetPriority(PRTYS_THREAD, g_pProcessPriority->aTypes[enmType].ulClass, g_pProcessPriority->aTypes[enmType].ulDelta, (ULONG)pThread->Core.Key & 0xffff /*tid*/);
+    AssertMsg(rc == NO_ERROR, ("%d\n", rc));
+    return RTErrConvertFromOS2(rc);
+#else
+    return VINF_SUCCESS;
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/os2/sems-os2.cpp b/src/VBox/Runtime/r3/os2/sems-os2.cpp
new file mode 100644
index 00000000..d4b8136e
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/sems-os2.cpp
@@ -0,0 +1,392 @@
+/* $Id: sems-os2.cpp $ */
+/** @file
+ * IPRT - Semaphores, OS/2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define INCL_DOSSEMAPHORES
+#define INCL_ERRORS
+#include <os2.h>
+#undef RT_MAX
+
+#include <iprt/semaphore.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+
+
+/** Converts semaphore to OS/2 handle. */
+#define SEM2HND(Sem) ((LHANDLE)(uintptr_t)Sem)
+
+
+
+RTDECL(int)  RTSemEventCreate(PRTSEMEVENT phEventSem)
+{
+    return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
+    Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
+
+    /*
+     * Create the semaphore.
+     * (Auto reset, not signaled, private event object.)
+     */
+    HEV hev;
+    int rc = DosCreateEventSem(NULL, &hev, DCE_AUTORESET | DCE_POSTONE, 0);
+    if (!rc)
+    {
+        *phEventSem = (RTSEMEVENT)(void *)hev;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(int)   RTSemEventDestroy(RTSEMEVENT hEventSem)
+{
+    if (hEventSem == NIL_RTSEMEVENT)
+        return VINF_SUCCESS;
+
+    /*
+     * Close semaphore handle.
+     */
+    int rc = DosCloseEventSem(SEM2HND(hEventSem));
+    if (!rc)
+        return VINF_SUCCESS;
+    AssertMsgFailed(("Destroy hEventSem %p failed, rc=%d\n", hEventSem, rc));
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(int)   RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    /*
+     * Wait for condition.
+     */
+    int rc = DosWaitEventSem(SEM2HND(hEventSem), cMillies == RT_INDEFINITE_WAIT ? SEM_INDEFINITE_WAIT : cMillies);
+    switch (rc)
+    {
+        case NO_ERROR:              return VINF_SUCCESS;
+        case ERROR_SEM_TIMEOUT:
+        case ERROR_TIMEOUT:         return VERR_TIMEOUT;
+        case ERROR_INTERRUPT:       return VERR_INTERRUPTED;
+        default:
+        {
+            AssertMsgFailed(("Wait on hEventSem %p failed, rc=%d\n", hEventSem, rc));
+            return RTErrConvertFromOS2(rc);
+        }
+    }
+}
+
+
+RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem)
+{
+    /*
+     * Signal the object.
+     */
+    int rc = DosPostEventSem(SEM2HND(hEventSem));
+    switch (rc)
+    {
+        case NO_ERROR:
+        case ERROR_ALREADY_POSTED:
+        case ERROR_TOO_MANY_POSTS:
+            return VINF_SUCCESS;
+        default:
+            return RTErrConvertFromOS2(rc);
+    }
+}
+
+
+RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+/** @todo implement RTSemEventSetSignaller and friends for OS/2 */
+}
+
+
+RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+
+}
+
+
+RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+
+}
+
+
+
+
+RTDECL(int)  RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem)
+{
+    return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
+                                     const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Create the semaphore.
+     * (Manual reset, not signaled, private event object.)
+     */
+    HEV hev;
+    int rc = DosCreateEventSem(NULL, &hev, 0, FALSE);
+    if (!rc)
+    {
+        *phEventMultiSem = (RTSEMEVENTMULTI)(void *)hev;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(int)  RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
+{
+    if (hEventMultiSem == NIL_RTSEMEVENTMULTI)
+        return VINF_SUCCESS;
+
+    /*
+     * Close semaphore handle.
+     */
+    int rc = DosCloseEventSem(SEM2HND(hEventMultiSem));
+    if (!rc)
+        return VINF_SUCCESS;
+    AssertMsgFailed(("Destroy hEventMultiSem %p failed, rc=%d\n", hEventMultiSem, rc));
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(int)  RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Signal the object.
+     */
+    int rc = DosPostEventSem(SEM2HND(hEventMultiSem));
+    switch (rc)
+    {
+        case NO_ERROR:
+        case ERROR_ALREADY_POSTED:
+        case ERROR_TOO_MANY_POSTS:
+            return VINF_SUCCESS;
+        default:
+            return RTErrConvertFromOS2(rc);
+    }
+}
+
+
+RTDECL(int)  RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Reset the object.
+     */
+    ULONG ulIgnore;
+    int rc = DosResetEventSem(SEM2HND(hEventMultiSem), &ulIgnore);
+    switch (rc)
+    {
+        case NO_ERROR:
+        case ERROR_ALREADY_RESET:
+            return VINF_SUCCESS;
+        default:
+            return RTErrConvertFromOS2(rc);
+    }
+}
+
+
+RTDECL(int)  RTSemEventMultiWaitNoResume(RTSEMEVENTMULTI hEventMultiSem, RTMSINTERVAL cMillies)
+{
+    /*
+     * Wait for condition.
+     */
+    int rc = DosWaitEventSem(SEM2HND(hEventMultiSem), cMillies == RT_INDEFINITE_WAIT ? SEM_INDEFINITE_WAIT : cMillies);
+    switch (rc)
+    {
+        case NO_ERROR:              return VINF_SUCCESS;
+        case ERROR_SEM_TIMEOUT:
+        case ERROR_TIMEOUT:         return VERR_TIMEOUT;
+        case ERROR_INTERRUPT:       return VERR_INTERRUPTED;
+        default:
+        {
+            AssertMsgFailed(("Wait on hEventMultiSem %p failed, rc=%d\n", hEventMultiSem, rc));
+            return RTErrConvertFromOS2(rc);
+        }
+    }
+}
+
+
+RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+    /** @todo implement RTSemEventMultiSetSignaller on OS/2 */
+}
+
+
+RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+}
+
+
+RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+}
+
+
+
+#undef RTSemMutexCreate
+RTDECL(int)  RTSemMutexCreate(PRTSEMMUTEX phMutexSem)
+{
+    return RTSemMutexCreateEx(phMutexSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+}
+
+
+RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags,
+                               RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Create the semaphore.
+     */
+    HMTX hmtx;
+    int rc = DosCreateMutexSem(NULL, &hmtx, 0, FALSE);
+    if (!rc)
+    {
+        /** @todo implement lock validation of OS/2 mutex semaphores. */
+        *phMutexSem = (RTSEMMUTEX)(void *)hmtx;
+        return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(int)  RTSemMutexDestroy(RTSEMMUTEX hMutexSem)
+{
+    if (hMutexSem == NIL_RTSEMMUTEX)
+        return VINF_SUCCESS;
+
+    /*
+     * Close semaphore handle.
+     */
+    int rc = DosCloseMutexSem(SEM2HND(hMutexSem));
+    if (!rc)
+        return VINF_SUCCESS;
+    AssertMsgFailed(("Destroy hMutexSem %p failed, rc=%d\n", hMutexSem, rc));
+    return RTErrConvertFromOS2(rc);
+}
+
+
+
+RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass)
+{
+#if 0 /** @todo def RTSEMMUTEX_STRICT */
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
+
+    return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass);
+#else
+    return RTLOCKVAL_SUB_CLASS_INVALID;
+#endif
+}
+
+
+#undef RTSemMutexRequestNoResume
+RTDECL(int)  RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+    /*
+     * Lock mutex semaphore.
+     */
+    int rc = DosRequestMutexSem(SEM2HND(hMutexSem), cMillies == RT_INDEFINITE_WAIT ? SEM_INDEFINITE_WAIT : cMillies);
+    switch (rc)
+    {
+        case NO_ERROR:              return VINF_SUCCESS;
+        case ERROR_SEM_TIMEOUT:
+        case ERROR_TIMEOUT:         return VERR_TIMEOUT;
+        case ERROR_INTERRUPT:       return VERR_INTERRUPTED;
+        case ERROR_SEM_OWNER_DIED:  return VERR_SEM_OWNER_DIED;
+        default:
+        {
+            AssertMsgFailed(("Wait on hMutexSem %p failed, rc=%d\n", hMutexSem, rc));
+            return RTErrConvertFromOS2(rc);
+        }
+    }
+}
+
+RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+//    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+//    return rtSemMutexRequestNoResume(hMutexSem, cMillies, &SrcPos);
+    return RTSemMutexRequestNoResume(hMutexSem, cMillies);
+}
+
+
+RTDECL(int)  RTSemMutexRelease(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Unlock mutex semaphore.
+     */
+    int rc = DosReleaseMutexSem(SEM2HND(hMutexSem));
+    if (!rc)
+        return VINF_SUCCESS;
+    AssertMsgFailed(("Release hMutexSem %p failed, rc=%d\n", hMutexSem, rc));
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Unlock mutex semaphore.
+     */
+    PID     pid;
+    TID     tid;
+    ULONG   cRecursions;
+    int rc = DosQueryMutexSem(SEM2HND(hMutexSem), &pid, &tid, &cRecursions);
+    if (!rc)
+        return cRecursions != 0;
+    AssertMsgFailed(("DosQueryMutexSem %p failed, rc=%d\n", hMutexSem, rc));
+    return rc == ERROR_SEM_OWNER_DIED;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/serialport-os2.cpp b/src/VBox/Runtime/r3/os2/serialport-os2.cpp
new file mode 100644
index 00000000..95158dea
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/serialport-os2.cpp
@@ -0,0 +1,755 @@
+/* $Id: serialport-os2.cpp $ */
+/** @file
+ * IPRT - Serial Port API, OS/2 Implementation.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define INCL_BASE
+#define INCL_DOSFILEMGR
+#define INCL_ERRORS
+#define INCL_DOS
+#define INCL_DOSDEVIOCTL
+#define INCL_DOSDEVICES
+#include <os2.h>
+#undef RT_MAX
+
+#include <iprt/serialport.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Returned data structure for ASYNC_EXTGETBAUDRATE.
+ */
+typedef struct OS2EXTGETBAUDRATEDATA
+{
+    /** Current bit rate. */
+    ULONG               uBitRateCur;
+    /** Fraction of the current bit rate. */
+    BYTE                bBitRateCurFrac;
+    /** Minimum supported bit rate. */
+    ULONG               uBitRateMin;
+    /** Fraction of the minimum bit rate. */
+    BYTE                bBitRateCurMin;
+    /** Maximum supported bit rate. */
+    ULONG               uBitRateMax;
+    /** Fraction of the maximum bit rate. */
+    BYTE                bBitRateCurMax;
+} OS2EXTGETBAUDRATEDATA;
+/** Pointer to the get extended baud rate data packet. */
+typedef OS2EXTGETBAUDRATEDATA *POS2EXTGETBAUDRATEDATA;
+
+
+/**
+ * Data packet for the ASYNC_EXTSETBAUDRATE ioctl.
+ */
+typedef struct OS2EXTSETBAUDRATEDATA
+{
+    /** Current bit rate. */
+    ULONG               uBitRate;
+    /** Fraction of the current bit rate. */
+    BYTE                bBitRateFrac;
+} OS2EXTSETBAUDRATEDATA;
+/** Pointer to the set extended baud rate data packet. */
+typedef OS2EXTSETBAUDRATEDATA *POS2EXTSETBAUDRATEDATA;
+
+
+/**
+ * Data packet for the ASYNC_GETLINECTRL ioctl.
+ */
+typedef struct OS2GETLINECTRLDATA
+{
+    /** Returns the current amount of data bits in a symbol used for the communication. */
+    BYTE                bDataBits;
+    /** Current parity setting. */
+    BYTE                bParity;
+    /** Current number of stop bits. */
+    BYTE                bStopBits;
+    /** Flag whether a break condition is currently transmitted on the line. */
+    BYTE                bTxBrk;
+} OS2GETLINECTRLDATA;
+/** Pointer to the get line control data packet. */
+typedef OS2GETLINECTRLDATA *POS2GETLINECTRLDATA;
+
+
+/**
+ * Data packet for the ASYNC_SETLINECTRL ioctl.
+ */
+typedef struct OS2SETLINECTRLDATA
+{
+    /** Returns the current amount of data bits in a symbol used for the communication. */
+    BYTE                bDataBits;
+    /** Current parity setting. */
+    BYTE                bParity;
+    /** Current number of stop bits. */
+    BYTE                bStopBits;
+} OS2SETLINECTRLDATA;
+/** Pointer to the get line control data packet. */
+typedef OS2SETLINECTRLDATA *POS2SETLINECTRLDATA;
+
+
+/**
+ * Internal serial port state.
+ */
+typedef struct RTSERIALPORTINTERNAL
+{
+    /** Magic value (RTSERIALPORT_MAGIC). */
+    uint32_t            u32Magic;
+    /** Flags given while opening the serial port. */
+    uint32_t            fOpenFlags;
+    /** The file descriptor of the serial port. */
+    HFILE               hDev;
+    /** Flag whether blocking mode is currently enabled. */
+    bool                fBlocking;
+    /** Flag whether RTSerialPortEvtPoll() was interrupted by RTSerialPortEvtPollInterrupt(). */
+    volatile bool       fInterrupt;
+} RTSERIALPORTINTERNAL;
+/** Pointer to the internal serial port state. */
+typedef RTSERIALPORTINTERNAL *PRTSERIALPORTINTERNAL;
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+
+/** Indicator whether the CTS input is set/clear. */
+#define OS2_GET_MODEM_INPUT_CTS         RT_BIT(4)
+/** Indicator whether the DSR input is set/clear. */
+#define OS2_GET_MODEM_INPUT_DSR         RT_BIT(5)
+/** Indicator whether the RI input is set/clear. */
+#define OS2_GET_MODEM_INPUT_RI          RT_BIT(6)
+/** Indicator whether the DCD input is set/clear. */
+#define OS2_GET_MODEM_INPUT_DCD         RT_BIT(7)
+
+/** There is something to read on the serial port. */
+#define OS2_GET_COMM_EVT_RX             RT_BIT(0)
+/** A receive timeout interrupt was generated on the serial port during a read request. */
+#define OS2_GET_COMM_EVT_RTI            RT_BIT(1)
+/** The transmit queue for the serial port is empty. */
+#define OS2_GET_COMM_EVT_TX_EMPTY       RT_BIT(2)
+/** The CTS signal changes state. */
+#define OS2_GET_COMM_EVT_CTS_CHG        RT_BIT(3)
+/** The DSR signal changes state. */
+#define OS2_GET_COMM_EVT_DSR_CHG        RT_BIT(4)
+/** The DCD signal changes state. */
+#define OS2_GET_COMM_EVT_DCD_CHG        RT_BIT(5)
+/** A break condition was detected on the serial port. */
+#define OS2_GET_COMM_EVT_BRK            RT_BIT(6)
+/** A parity, framing or receive hardware overrun error occurred. */
+#define OS2_GET_COMM_EVT_COMM_ERR       RT_BIT(7)
+/** Trailing edge ring indicator was detected. */
+#define OS2_GET_COMM_EVT_RI_TRAIL_EDGE  RT_BIT(8)
+
+
+/*********************************************************************************************************************************
+*   Global variables                                                                                                             *
+*********************************************************************************************************************************/
+/** OS/2 parity value to IPRT parity enum. */
+static RTSERIALPORTPARITY s_aParityConvTbl[] =
+{
+    RTSERIALPORTPARITY_NONE,
+    RTSERIALPORTPARITY_ODD,
+    RTSERIALPORTPARITY_EVEN,
+    RTSERIALPORTPARITY_MARK,
+    RTSERIALPORTPARITY_SPACE
+};
+
+/** OS/2 data bits value to IPRT data bits enum. */
+static RTSERIALPORTDATABITS s_aDataBitsConvTbl[] =
+{
+    RTSERIALPORTDATABITS_INVALID,
+    RTSERIALPORTDATABITS_INVALID,
+    RTSERIALPORTDATABITS_INVALID,
+    RTSERIALPORTDATABITS_INVALID,
+    RTSERIALPORTDATABITS_INVALID,
+    RTSERIALPORTDATABITS_5BITS,
+    RTSERIALPORTDATABITS_6BITS,
+    RTSERIALPORTDATABITS_7BITS,
+    RTSERIALPORTDATABITS_8BITS
+};
+
+/** OS/2 stop bits value to IPRT stop bits enum. */
+static RTSERIALPORTSTOPBITS s_aStopBitsConvTbl[] =
+{
+    RTSERIALPORTSTOPBITS_ONE,
+    RTSERIALPORTSTOPBITS_ONEPOINTFIVE,
+    RTSERIALPORTSTOPBITS_TWO
+};
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * The slow path of rtSerialPortSwitchBlockingMode that does the actual switching.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fBlocking               The desired mode of operation.
+ * @remarks Do not call directly.
+ *
+ * @note Affects only read behavior.
+ */
+static int rtSerialPortSwitchBlockingModeSlow(PRTSERIALPORTINTERNAL pThis, bool fBlocking)
+{
+    DCBINFO DcbInfo;
+    ULONG cbDcbInfo = sizeof(DcbInfo);
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_GETDCBINFO, NULL, 0, NULL, &DcbInfo, cbDcbInfo, &cbDcbInfo);
+    if (!rcOs2)
+    {
+        DcbInfo.fbTimeout &= ~0x06;
+        DcbInfo.fbTimeout |= fBlocking ? 0x04 : 0x06;
+        rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_SETDCBINFO, &DcbInfo, cbDcbInfo, &cbDcbInfo, NULL, 0, NULL);
+        if (rcOs2)
+            return RTErrConvertFromOS2(rcOs2);
+    }
+    else
+        return RTErrConvertFromOS2(rcOs2);
+
+    pThis->fBlocking = fBlocking;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Switches the serial port to the desired blocking mode if necessary.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fBlocking               The desired mode of operation.
+ *
+ * @note Affects only read behavior.
+ */
+DECLINLINE(int) rtSerialPortSwitchBlockingMode(PRTSERIALPORTINTERNAL pThis, bool fBlocking)
+{
+    if (pThis->fBlocking != fBlocking)
+        return rtSerialPortSwitchBlockingModeSlow(pThis, fBlocking);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSerialPortOpen(PRTSERIALPORT phSerialPort, const char *pszPortAddress, uint32_t fFlags)
+{
+    AssertPtrReturn(phSerialPort, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszPortAddress, VERR_INVALID_POINTER);
+    AssertReturn(*pszPortAddress != '\0', VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSERIALPORT_OPEN_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn((fFlags & RTSERIALPORT_OPEN_F_READ) || (fFlags & RTSERIALPORT_OPEN_F_WRITE),
+                 VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    PRTSERIALPORTINTERNAL pThis = (PRTSERIALPORTINTERNAL)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        ULONG fOpenMode =   OPEN_SHARE_DENYREADWRITE
+                          | OPEN_FLAGS_SEQUENTIAL
+                          | OPEN_FLAGS_NOINHERIT
+                          | OPEN_FLAGS_FAIL_ON_ERROR;
+
+        if ((fFlags & RTSERIALPORT_OPEN_F_READ) && !(fFlags & RTSERIALPORT_OPEN_F_WRITE))
+            fOpenMode |= OPEN_ACCESS_READONLY;
+        else if (!(fFlags & RTSERIALPORT_OPEN_F_READ) && (fFlags & RTSERIALPORT_OPEN_F_WRITE))
+            fOpenMode |= OPEN_ACCESS_WRITEONLY;
+        else
+            fOpenMode |= OPEN_ACCESS_READWRITE;
+
+        pThis->u32Magic     = RTSERIALPORT_MAGIC;
+        pThis->fOpenFlags   = fFlags;
+        pThis->fInterrupt   = false;
+        pThis->fBlocking    = true;
+
+        ULONG uAction = 0;
+        ULONG rcOs2 = DosOpen((const UCHAR *)pszPortAddress, &pThis->hDev, &uAction, 0, FILE_NORMAL, FILE_OPEN, fOpenMode, NULL);
+        if (!rcOs2)
+        {
+            /* Switch to a known read blocking mode. */
+            rc = rtSerialPortSwitchBlockingMode(pThis, false);
+            if (RT_SUCCESS(rc))
+            {
+                *phSerialPort = pThis;
+                return VINF_SUCCESS;
+            }
+
+            DosClose(pThis->hDev);
+        }
+        else
+            rc = RTErrConvertFromOS2(rcOs2);
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortClose(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    if (pThis == NIL_RTSERIALPORT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSERIALPORT_MAGIC_DEAD, RTSERIALPORT_MAGIC), VERR_INVALID_HANDLE);
+
+    DosClose(pThis->hDev);
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTHCINTPTR) RTSerialPortToNative(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, -1);
+
+    return pThis->hDev;
+}
+
+
+RTDECL(int) RTSerialPortRead(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, true);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Attempt read.
+         */
+        ULONG cbRead = 0;
+        ULONG rcOs2 = DosRead(pThis->hDev, pvBuf, cbToRead, &cbRead);
+        if (!rcOs2)
+        {
+            if (pcbRead)
+                /* caller can handle partial read. */
+                *pcbRead = cbRead;
+            else
+            {
+                /* Caller expects all to be read. */
+                while (cbToRead > cbRead)
+                {
+                    ULONG cbReadPart = 0;
+                    rcOs2 = DosRead(pThis->hDev, (uint8_t *)pvBuf + cbRead, cbToRead - cbRead, &cbReadPart);
+                    if (rcOs2)
+                        return RTErrConvertFromOS2(rcOs2);
+
+                    cbRead += cbReadPart;
+                }
+            }
+        }
+        else
+            rc = RTErrConvertFromOS2(rcOs2);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortReadNB(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbRead, VERR_INVALID_POINTER);
+
+    *pcbRead = 0;
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, false);
+    if (RT_SUCCESS(rc))
+    {
+        ULONG cbThisRead = 0;
+        ULONG rcOs2 = DosRead(pThis->hDev, pvBuf, cbToRead, &cbThisRead);
+        if (!rcOs2)
+        {
+            *pcbRead = cbThisRead;
+
+            if (cbThisRead == 0)
+                rc = VINF_TRY_AGAIN;
+        }
+        else
+            rc = RTErrConvertFromOS2(rcOs2);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWrite(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+
+    /*
+     * Attempt write.
+     */
+    int rc = VINF_SUCCESS;
+    ULONG cbThisWritten = 0;
+    ULONG rcOs2 = DosWrite(pThis->hDev, pvBuf, cbToWrite, &cbThisWritten);
+    if (!rcOs2)
+    {
+        if (pcbWritten)
+            /* caller can handle partial write. */
+            *pcbWritten = cbThisWritten;
+        else
+        {
+            /** @todo Wait for TX empty and loop. */
+            rc = VERR_NOT_SUPPORTED;
+        }
+    }
+    else
+        rc = RTErrConvertFromOS2(rcOs2);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWriteNB(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_POINTER);
+
+    *pcbWritten = 0;
+
+    int rc = VINF_SUCCESS;
+    ULONG cbThisWritten = 0;
+    ULONG rcOs2 = DosWrite(pThis->hDev, pvBuf, cbToWrite, &cbThisWritten);
+    if (!rcOs2)
+    {
+        *pcbWritten = cbThisWritten;
+        if (!cbThisWritten)
+            rc = VINF_TRY_AGAIN;
+    }
+    else
+        rc = RTErrConvertFromOS2(rcOs2);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortCfgQueryCurrent(RTSERIALPORT hSerialPort, PRTSERIALPORTCFG pCfg)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    int rc = VINF_SUCCESS;
+    OS2EXTGETBAUDRATEDATA ExtBaudRate;
+    ULONG cbExtBaudRate = sizeof(ExtBaudRate);
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_EXTGETBAUDRATE, NULL, 0, NULL, &ExtBaudRate, cbExtBaudRate, &cbExtBaudRate);
+    if (!rcOs2)
+    {
+        OS2GETLINECTRLDATA LineCtrl;
+        ULONG cbLineCtrl = sizeof(LineCtrl);
+        rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_GETLINECTRL, NULL, 0, NULL, &LineCtrl, cbLineCtrl, &cbLineCtrl);
+        if (!rcOs2)
+        {
+            pCfg->uBaudRate = ExtBaudRate.uBitRateCur;
+            if (LineCtrl.bParity < RT_ELEMENTS(s_aParityConvTbl))
+                pCfg->enmParity = s_aParityConvTbl[LineCtrl.bParity];
+            else
+                rc = VERR_IPE_UNEXPECTED_STATUS;
+
+            if (   RT_SUCCESS(rc)
+                && LineCtrl.bDataBits < RT_ELEMENTS(s_aDataBitsConvTbl)
+                && s_aDataBitsConvTbl[LineCtrl.bDataBits] != RTSERIALPORTDATABITS_INVALID)
+                pCfg->enmDataBitCount = s_aDataBitsConvTbl[LineCtrl.bDataBits];
+            else
+                rc = VERR_IPE_UNEXPECTED_STATUS;
+
+            if (   RT_SUCCESS(rc)
+                && LineCtrl.bStopBits < RT_ELEMENTS(s_aStopBitsConvTbl))
+                pCfg->enmStopBitCount = s_aStopBitsConvTbl[LineCtrl.bStopBits];
+            else
+                rc = VERR_IPE_UNEXPECTED_STATUS;
+        }
+        else
+            rc = RTErrConvertFromOS2(rcOs2);
+    }
+    else
+        rc = RTErrConvertFromOS2(rcOs2);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortCfgSet(RTSERIALPORT hSerialPort, PCRTSERIALPORTCFG pCfg, PRTERRINFO pErrInfo)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    int rc = VINF_SUCCESS;
+    OS2EXTSETBAUDRATEDATA ExtBaudRate;
+    OS2SETLINECTRLDATA LineCtrl;
+    ULONG cbExtBaudRate = sizeof(ExtBaudRate);
+    ULONG cbLineCtrl = sizeof(LineCtrl);
+
+    ExtBaudRate.uBitRate     = pCfg->uBaudRate;
+    ExtBaudRate.bBitRateFrac = 0;
+
+    BYTE idx = 0;
+    while (idx < RT_ELEMENTS(s_aParityConvTbl))
+    {
+        if (s_aParityConvTbl[idx] == pCfg->enmParity)
+        {
+            LineCtrl.bParity = idx;
+            break;
+        }
+        idx++;
+    }
+    AssertReturn(idx < RT_ELEMENTS(s_aParityConvTbl), VERR_INTERNAL_ERROR);
+
+    idx = 0;
+    while (idx < RT_ELEMENTS(s_aDataBitsConvTbl))
+    {
+        if (s_aDataBitsConvTbl[idx] == pCfg->enmDataBitCount)
+        {
+            LineCtrl.bDataBits = idx;
+            break;
+        }
+        idx++;
+    }
+    AssertReturn(idx < RT_ELEMENTS(s_aDataBitsConvTbl), VERR_INTERNAL_ERROR);
+
+    idx = 0;
+    while (idx < RT_ELEMENTS(s_aStopBitsConvTbl))
+    {
+        if (s_aStopBitsConvTbl[idx] == pCfg->enmStopBitCount)
+        {
+            LineCtrl.bStopBits = idx;
+            break;
+        }
+        idx++;
+    }
+    AssertReturn(idx < RT_ELEMENTS(s_aStopBitsConvTbl), VERR_INTERNAL_ERROR);
+
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_EXTSETBAUDRATE, &ExtBaudRate, cbExtBaudRate, &cbExtBaudRate, NULL, 0, NULL);
+    if (!rcOs2)
+    {
+        rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_SETLINECTRL, &LineCtrl, cbLineCtrl, &cbLineCtrl, NULL, 0, NULL);
+        if (rcOs2)
+            rc = RTErrConvertFromOS2(rcOs2);
+    }
+    else
+        rc = RTErrConvertFromOS2(rcOs2);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPoll(RTSERIALPORT hSerialPort, uint32_t fEvtMask, uint32_t *pfEvtsRecv,
+                                RTMSINTERVAL msTimeout)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fEvtMask & ~RTSERIALPORT_EVT_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfEvtsRecv, VERR_INVALID_POINTER);
+
+    *pfEvtsRecv = 0;
+
+    /*
+     * We need to kind of busy wait here as there is, to my knowledge, no API
+     * to wait for a COM event.
+     *
+     * @todo Adaptive waiting
+     * @todo Handle rollover after 48days eventually
+     */
+    int rc = VINF_SUCCESS;
+    uint64_t tsStart = RTTimeSystemMilliTS();
+    do
+    {
+        if (ASMAtomicXchgBool(&pThis->fInterrupt, false))
+        {
+            rc = VERR_INTERRUPTED;
+            break;
+        }
+
+        USHORT fCommEvt = 0;
+        ULONG cbCommEvt = sizeof(fCommEvt);
+        ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_GETCOMMEVENT, NULL, 0, NULL,
+                                  &fCommEvt, cbCommEvt, &cbCommEvt);
+        if (!rcOs2)
+        {
+            AssertReturn(cbCommEvt = sizeof(fCommEvt), VERR_IPE_UNEXPECTED_STATUS);
+
+            if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX)
+                && (fCommEvt & OS2_GET_COMM_EVT_RX))
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_RX;
+
+            /** @todo Is there something better to indicate that there is room in the queue instead of queue is empty? */
+            if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX)
+                && (fCommEvt & OS2_GET_COMM_EVT_TX_EMPTY))
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+
+            if (   (fEvtMask & RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED)
+                && (fCommEvt & (OS2_GET_COMM_EVT_CTS_CHG | OS2_GET_COMM_EVT_DSR_CHG | OS2_GET_COMM_EVT_DCD_CHG)))
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED;
+
+            if (   (fEvtMask & RTSERIALPORT_EVT_F_BREAK_DETECTED)
+                && (fCommEvt & OS2_GET_COMM_EVT_BRK))
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_BREAK_DETECTED;
+
+            if (*pfEvtsRecv != 0)
+                break;
+        }
+        else
+        {
+            rc = RTErrConvertFromOS2(rcOs2);
+            break;
+        }
+
+        uint64_t tsNow = RTTimeSystemMilliTS();
+        if (   msTimeout == RT_INDEFINITE_WAIT
+            || tsNow - tsStart < msTimeout)
+            DosSleep(1);
+        else
+            rc = VERR_TIMEOUT;
+    } while (RT_SUCCESS(rc));
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPollInterrupt(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    ASMAtomicXchgBool(&pThis->fInterrupt, true);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSerialPortChgBreakCondition(RTSERIALPORT hSerialPort, bool fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, fSet ? ASYNC_SETBREAKON : ASYNC_SETBREAKOFF,
+                              NULL, 0, NULL, NULL, 0, NULL);
+
+    return RTErrConvertFromOS2(rcOs2);
+}
+
+
+RTDECL(int) RTSerialPortChgStatusLines(RTSERIALPORT hSerialPort, uint32_t fClear, uint32_t fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    MODEMSTATUS MdmSts;
+    ULONG cbMdmSts = sizeof(MdmSts);
+
+    MdmSts.fbModemOn =    (fSet & RTSERIALPORT_CHG_STS_LINES_F_RTS ? 0x02 : 0x00)
+                        | (fSet & RTSERIALPORT_CHG_STS_LINES_F_DTR ? 0x01 : 0x00);
+    MdmSts.fbModemOff = 0xff;
+    MdmSts.fbModemOff &= ~(  (fClear & RTSERIALPORT_CHG_STS_LINES_F_RTS ? 0x02 : 0x00)
+                           | (fClear & RTSERIALPORT_CHG_STS_LINES_F_DTR ? 0x01 : 0x00));
+
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_SETMODEMCTRL, &MdmSts, cbMdmSts, &cbMdmSts, NULL, 0, NULL);
+
+    return RTErrConvertFromOS2(rcOs2);
+}
+
+
+RTDECL(int) RTSerialPortQueryStatusLines(RTSERIALPORT hSerialPort, uint32_t *pfStsLines)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfStsLines, VERR_INVALID_POINTER);
+
+    *pfStsLines = 0;
+
+    int rc = VINF_SUCCESS;
+    BYTE fStsLines = 0;
+    ULONG cbStsLines = sizeof(fStsLines);
+    ULONG rcOs2 = DosDevIOCtl(pThis->hDev, IOCTL_ASYNC, ASYNC_GETMODEMINPUT, NULL, 0, NULL, &fStsLines, cbStsLines, &cbStsLines);
+    if (!rcOs2)
+    {
+        AssertReturn(cbStsLines == sizeof(BYTE), VERR_IPE_UNEXPECTED_STATUS);
+
+        *pfStsLines |= (fStsLines & OS2_GET_MODEM_INPUT_DCD) ? RTSERIALPORT_STS_LINE_DCD : 0;
+        *pfStsLines |= (fStsLines & OS2_GET_MODEM_INPUT_RI)  ? RTSERIALPORT_STS_LINE_RI  : 0;
+        *pfStsLines |= (fStsLines & OS2_GET_MODEM_INPUT_DSR) ? RTSERIALPORT_STS_LINE_DSR : 0;
+        *pfStsLines |= (fStsLines & OS2_GET_MODEM_INPUT_CTS) ? RTSERIALPORT_STS_LINE_CTS : 0;
+    }
+    else
+        rc = RTErrConvertFromOS2(rcOs2);
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/systemmem-os2.cpp b/src/VBox/Runtime/r3/os2/systemmem-os2.cpp
new file mode 100644
index 00000000..71eb1adf
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/systemmem-os2.cpp
@@ -0,0 +1,80 @@
+/* $Id: systemmem-os2.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, OS/2 ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define INCL_DOSMISC
+#define INCL_ERRORS
+#include <os2.h>
+#undef RT_MAX
+
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    ULONG cbMem;
+    APIRET rc = DosQuerySysInfo(QSV_TOTPHYSMEM, QSV_TOTPHYSMEM, &cbMem, sizeof(cbMem));
+    if (rc != NO_ERROR)
+        return RTErrConvertFromOS2(rc);
+
+    *pcb = cbMem;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    ULONG cbAvailMem;
+    APIRET rc = DosQuerySysInfo(QSV_TOTAVAILMEM, QSV_TOTAVAILMEM, &cbAvailMem, sizeof(cbAvailMem));
+    if (rc != NO_ERROR)
+        return RTErrConvertFromOS2(rc);
+
+    *pcb = cbAvailMem;
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/os2/thread-os2.cpp b/src/VBox/Runtime/r3/os2/thread-os2.cpp
new file mode 100644
index 00000000..366f4803
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/thread-os2.cpp
@@ -0,0 +1,330 @@
+/* $Id: thread-os2.cpp $ */
+/** @file
+ * IPRT - Threads, OS/2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#define INCL_BASE
+#include <os2.h>
+#undef RT_MAX
+
+#include <errno.h>
+#include <process.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <InnoTekLIBC/FastInfoBlocks.h>
+#include <InnoTekLIBC/thread.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/alloc.h>
+#include <iprt/asm-amd64-x86.h>
+#include <iprt/cpuset.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Pointer to thread local memory which points to the current thread. */
+static PRTTHREADINT *g_ppCurThread;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static void rtThreadNativeMain(void *pvArgs);
+
+
+DECLHIDDEN(int) rtThreadNativeInit(void)
+{
+    /*
+     * Allocate thread local memory.
+     */
+    PULONG pul;
+    int rc = DosAllocThreadLocalMemory(1, &pul);
+    if (rc)
+        return VERR_NO_TLS_FOR_SELF;
+    g_ppCurThread = (PRTTHREADINT *)(void *)pul;
+    return VINF_SUCCESS;
+}
+
+
+static void rtThreadOs2BlockSigAlarm(void)
+{
+    /*
+     * Block SIGALRM - required for timer-posix.cpp.
+     * This is done to limit harm done by OSes which doesn't do special SIGALRM scheduling.
+     * It will not help much if someone creates threads directly using pthread_create. :/
+     */
+    sigset_t SigSet;
+    sigemptyset(&SigSet);
+    sigaddset(&SigSet, SIGALRM);
+    sigprocmask(SIG_BLOCK, &SigSet, NULL);
+}
+
+
+DECLHIDDEN(void) rtThreadNativeReInitObtrusive(void)
+{
+    rtThreadOs2BlockSigAlarm();
+}
+
+
+DECLHIDDEN(int) rtThreadNativeAdopt(PRTTHREADINT pThread)
+{
+
+    *g_ppCurThread = pThread;
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(void) rtThreadNativeDestroy(PRTTHREADINT pThread)
+{
+    if (pThread == *g_ppCurThread)
+        *g_ppCurThread = NULL;
+}
+
+
+/**
+ * Wrapper which unpacks the params and calls thread function.
+ */
+static void rtThreadNativeMain(void *pvArgs)
+{
+    rtThreadOs2BlockSigAlarm();
+
+    /*
+     * Call common main.
+     */
+    PRTTHREADINT  pThread = (PRTTHREADINT)pvArgs;
+    *g_ppCurThread = pThread;
+
+#ifdef fibGetTidPid
+    rtThreadMain(pThread, fibGetTidPid(), &pThread->szName[0]);
+#else
+    rtThreadMain(pThread, _gettid(), &pThread->szName[0]);
+#endif
+
+    *g_ppCurThread = NULL;
+    _endthread();
+}
+
+
+DECLHIDDEN(int) rtThreadNativeCreate(PRTTHREADINT pThread, PRTNATIVETHREAD pNativeThread)
+{
+    /*
+     * Default stack size.
+     */
+    if (!pThread->cbStack)
+        pThread->cbStack = 512*1024;
+
+    /*
+     * Create the thread.
+     */
+    int iThreadId = _beginthread(rtThreadNativeMain, NULL, pThread->cbStack, pThread);
+    if (iThreadId > 0)
+    {
+#ifdef fibGetTidPid
+        *pNativeThread = iThreadId | (fibGetPid() << 16);
+#else
+        *pNativeThread = iThreadId;
+#endif
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(RTTHREAD) RTThreadSelf(void)
+{
+    PRTTHREADINT pThread = *g_ppCurThread;
+    if (pThread)
+        return (RTTHREAD)pThread;
+    /** @todo import alien threads? */
+    return NULL;
+}
+
+
+RTDECL(RTNATIVETHREAD) RTThreadNativeSelf(void)
+{
+#ifdef fibGetTidPid
+    return fibGetTidPid();
+#else
+    return _gettid();
+#endif
+}
+
+
+RTDECL(int)   RTThreadSleep(RTMSINTERVAL cMillies)
+{
+    LogFlow(("RTThreadSleep: cMillies=%d\n", cMillies));
+    DosSleep(cMillies);
+    LogFlow(("RTThreadSleep: returning (cMillies=%d)\n", cMillies));
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)   RTThreadSleepNoLog(RTMSINTERVAL cMillies)
+{
+    DosSleep(cMillies);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(bool) RTThreadYield(void)
+{
+    uint64_t u64TS = ASMReadTSC();
+    DosSleep(0);
+    u64TS = ASMReadTSC() - u64TS;
+    bool fRc = u64TS > 1750;
+    LogFlow(("RTThreadYield: returning %d (%llu ticks)\n", fRc, u64TS));
+    return fRc;
+}
+
+
+RTR3DECL(int) RTThreadGetAffinity(PRTCPUSET pCpuSet)
+{
+    union
+    {
+        uint64_t u64;
+        MPAFFINITY mpaff;
+    } u;
+
+    APIRET rc = DosQueryThreadAffinity(AFNTY_THREAD, &u.mpaff);
+    if (!rc)
+    {
+        RTCpuSetFromU64(pCpuSet, u.u64);
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTR3DECL(int) RTThreadSetAffinity(PCRTCPUSET pCpuSet)
+{
+    union
+    {
+        uint64_t u64;
+        MPAFFINITY mpaff;
+    } u;
+    u.u64 = pCpuSet ? RTCpuSetToU64(pCpuSet) : UINT64_MAX;
+    int rc = DosSetThreadAffinity(&u.mpaff);
+    if (!rc)
+        return VINF_SUCCESS;
+    return RTErrConvertFromOS2(rc);
+}
+
+
+RTR3DECL(RTTLS) RTTlsAlloc(void)
+{
+    AssertCompile(NIL_RTTLS == -1);
+    return __libc_TLSAlloc();
+}
+
+
+RTR3DECL(int) RTTlsAllocEx(PRTTLS piTls, PFNRTTLSDTOR pfnDestructor)
+{
+    int rc;
+    int iTls = __libc_TLSAlloc();
+    if (iTls != -1)
+    {
+        if (    !pfnDestructor
+            ||  __libc_TLSDestructor(iTls, (void (*)(void *, int, unsigned))pfnDestructor, 0) != -1)
+        {
+            *piTls = iTls;
+            return VINF_SUCCESS;
+        }
+
+        rc = RTErrConvertFromErrno(errno);
+        __libc_TLSFree(iTls);
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+
+    *piTls = NIL_RTTLS;
+    return rc;
+}
+
+
+RTR3DECL(int) RTTlsFree(RTTLS iTls)
+{
+    if (iTls == NIL_RTTLS)
+        return VINF_SUCCESS;
+    if (__libc_TLSFree(iTls) != -1)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(void *) RTTlsGet(RTTLS iTls)
+{
+    return __libc_TLSGet(iTls);
+}
+
+
+RTR3DECL(int) RTTlsGetEx(RTTLS iTls, void **ppvValue)
+{
+    int rc = VINF_SUCCESS;
+    void *pv = __libc_TLSGet(iTls);
+    if (RT_UNLIKELY(!pv))
+    {
+        errno = 0;
+        pv = __libc_TLSGet(iTls);
+        if (!pv && errno)
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    *ppvValue = pv;
+    return rc;
+}
+
+
+RTR3DECL(int) RTTlsSet(RTTLS iTls, void *pvValue)
+{
+    if (__libc_TLSSet(iTls, pvValue) != -1)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTThreadGetExecutionTimeMilli(uint64_t *pKernelTime, uint64_t *pUserTime)
+{
+    return VERR_NOT_IMPLEMENTED;
+}
diff --git a/src/VBox/Runtime/r3/os2/time-os2.cpp b/src/VBox/Runtime/r3/os2/time-os2.cpp
new file mode 100644
index 00000000..e06b9fcd
--- /dev/null
+++ b/src/VBox/Runtime/r3/os2/time-os2.cpp
@@ -0,0 +1,87 @@
+/* $Id: time-os2.cpp $ */
+/** @file
+ * IPRT - Time, OS/2.
+ */
+
+/*
+ * Contributed by knut st. osmundsen.
+ *
+ * Copyright (C) 2007-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ * --------------------------------------------------------------------
+ *
+ * This code is based on:
+ *
+ * Copyright (c) 2007 knut st. osmundsen <bird-src-spam@anduin.net>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#include <InnoTekLIBC/FastInfoBlocks.h>
+
+#include <iprt/time.h>
+#include "internal/time.h"
+
+/** @todo mscount will roll over after ~48 days. */
+
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return fibGetMsCount() * UINT64_C(10000000);
+}
+
+
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return fibGetMsCount();
+}
+
diff --git a/src/VBox/Runtime/r3/path.cpp b/src/VBox/Runtime/r3/path.cpp
new file mode 100644
index 00000000..bcd8deb1
--- /dev/null
+++ b/src/VBox/Runtime/r3/path.cpp
@@ -0,0 +1,163 @@
+/* $Id: path.cpp $ */
+/** @file
+ * IPRT - Path Manipulation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/path.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include "internal/path.h"
+#include "internal/process.h"
+
+
+#ifdef RT_OS_SOLARIS
+/**
+ * Hack to strip of the architecture subdirectory from the exec dir.
+ *
+ * @returns See RTPathExecDir.
+ * @param   pszPath             See RTPathExecDir.
+ * @param   cchPath             See RTPathExecDir.
+ */
+DECLINLINE(int) rtPathSolarisArchHack(char *pszPath, size_t cchPath)
+{
+    int rc = RTPathExecDir(pszPath, cchPath);
+    if (RT_SUCCESS(rc))
+    {
+        const char *pszLast = RTPathFilename(pszPath);
+        if (   !strcmp(pszLast, "amd64")
+            || !strcmp(pszLast, "i386"))
+            RTPathStripFilename(pszPath);
+    }
+    return rc;
+}
+#endif
+
+
+RTDECL(int) RTPathExecDir(char *pszPath, size_t cchPath)
+{
+    AssertReturn(g_szrtProcExePath[0], VERR_WRONG_ORDER);
+
+    /*
+     * Calc the length and check if there is space before copying.
+     */
+    size_t cch = g_cchrtProcExeDir;
+    if (cch < cchPath)
+    {
+        memcpy(pszPath, g_szrtProcExePath, cch);
+        pszPath[cch] = '\0';
+        return VINF_SUCCESS;
+    }
+
+    AssertMsgFailed(("Buffer too small (%zu <= %zu)\n", cchPath, cch));
+    return VERR_BUFFER_OVERFLOW;
+}
+
+
+RTDECL(int) RTPathAppPrivateNoArch(char *pszPath, size_t cchPath)
+{
+#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE)
+    return RTStrCopy(pszPath, cchPath, RTPATH_APP_PRIVATE);
+#elif defined(RT_OS_SOLARIS)
+    return rtPathSolarisArchHack(pszPath, cchPath);
+#else
+    return RTPathExecDir(pszPath, cchPath);
+#endif
+}
+
+
+RTDECL(int) RTPathAppPrivateArch(char *pszPath, size_t cchPath)
+{
+#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
+    return RTStrCopy(pszPath, cchPath, RTPATH_APP_PRIVATE_ARCH);
+#else
+    return RTPathExecDir(pszPath, cchPath);
+#endif
+}
+
+
+RTDECL(int) RTPathAppPrivateArchTop(char *pszPath, size_t cchPath)
+{
+#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH_TOP)
+    return RTStrCopy(pszPath, cchPath, RTPATH_APP_PRIVATE_ARCH_TOP);
+#elif !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_PRIVATE_ARCH)
+    return RTStrCopy(pszPath, cchPath, RTPATH_APP_PRIVATE_ARCH);
+#elif defined(RT_OS_SOLARIS)
+    return rtPathSolarisArchHack(pszPath, cchPath);
+#else
+    int rc = RTPathExecDir(pszPath, cchPath);
+    return rc;
+#endif
+}
+
+
+RTDECL(int) RTPathSharedLibs(char *pszPath, size_t cchPath)
+{
+#if !defined(RT_OS_WINDOWS) && defined(RTPATH_SHARED_LIBS)
+    return RTStrCopy(pszPath, cchPath, RTPATH_SHARED_LIBS);
+#else
+    return RTPathExecDir(pszPath, cchPath);
+#endif
+}
+
+
+RTDECL(int) RTPathAppDocs(char *pszPath, size_t cchPath)
+{
+#if !defined(RT_OS_WINDOWS) && defined(RTPATH_APP_DOCS)
+    return RTStrCopy(pszPath, cchPath, RTPATH_APP_DOCS);
+#elif defined(RT_OS_SOLARIS)
+    return rtPathSolarisArchHack(pszPath, cchPath);
+#else
+    return RTPathExecDir(pszPath, cchPath);
+#endif
+}
+
+
+RTR3DECL(int) RTPathGetMode(const char *pszPath, PRTFMODE pfMode)
+{
+    AssertPtrReturn(pfMode, VERR_INVALID_POINTER);
+
+    RTFSOBJINFO ObjInfo;
+    int rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_FOLLOW_LINK);
+    if (RT_SUCCESS(rc))
+        *pfMode = ObjInfo.Attr.fMode;
+
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/poll.cpp b/src/VBox/Runtime/r3/poll.cpp
new file mode 100644
index 00000000..51286e0c
--- /dev/null
+++ b/src/VBox/Runtime/r3/poll.cpp
@@ -0,0 +1,1148 @@
+/* $Id: poll.cpp $ */
+/** @file
+ * IPRT - Polling I/O Handles, Windows+Posix Implementation.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cdefs.h>
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/windows.h>
+
+#elif defined(RT_OS_OS2)
+# define INCL_BASE
+# include <os2.h>
+# include <limits.h>
+# include <sys/socket.h>
+
+#else
+# include <limits.h>
+# include <errno.h>
+# include <sys/poll.h>
+# if defined(RT_OS_SOLARIS)
+#  include <sys/socket.h>
+# endif
+#endif
+
+#include <iprt/poll.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/pipe.h>
+#include <iprt/socket.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+
+#include "internal/pipe.h"
+#define IPRT_INTERNAL_SOCKET_POLLING_ONLY
+#include "internal/socket.h"
+#include "internal/magics.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The maximum poll set size.
+ * @remarks To help portability, we set this to the Windows limit. We can lift
+ *          this restriction later if it becomes necessary. */
+#define RTPOLL_SET_MAX     64
+
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Handle entry in a poll set.
+ */
+typedef struct RTPOLLSETHNDENT
+{
+    /** The handle type. */
+    RTHANDLETYPE    enmType;
+    /** The handle ID. */
+    uint32_t        id;
+    /** The events we're waiting for here. */
+    uint32_t        fEvents;
+    /** Set if this is the final entry for this handle.
+     * If the handle is entered more than once, this will be clear for all but
+     * the last entry. */
+    bool            fFinalEntry;
+    /** The handle union. */
+    RTHANDLEUNION   u;
+} RTPOLLSETHNDENT;
+/** Pointer to a handle entry. */
+typedef RTPOLLSETHNDENT *PRTPOLLSETHNDENT;
+
+
+/**
+ * Poll set data.
+ */
+typedef struct RTPOLLSETINTERNAL
+{
+    /** The magic value (RTPOLLSET_MAGIC). */
+    uint32_t            u32Magic;
+    /** Set when someone is polling or making changes. */
+    bool volatile       fBusy;
+
+    /** The number of allocated handles. */
+    uint16_t            cHandlesAllocated;
+    /** The number of valid handles in the set. */
+    uint16_t            cHandles;
+
+#ifdef RT_OS_WINDOWS
+    /** Pointer to an array of native handles. */
+    HANDLE             *pahNative;
+#elif defined(RT_OS_OS2)
+    /** The semaphore records. */
+    PSEMRECORD          paSemRecs;
+    /** The multiple wait semaphore used for non-socket waits. */
+    HMUX                hmux;
+    /** os2_select template. */
+    int                *pafdSelect;
+    /** The number of sockets to monitor for read. */
+    uint16_t            cReadSockets;
+    /** The number of sockets to monitor for write. */
+    uint16_t            cWriteSockets;
+    /** The number of sockets to monitor for exceptions. */
+    uint16_t            cXcptSockets;
+    /** The number of pipes. */
+    uint16_t            cPipes;
+    /** Pointer to an array of native handles. */
+    PRTHCINTPTR         pahNative;
+#else
+    /** Pointer to an array of pollfd structures. */
+    struct pollfd      *paPollFds;
+#endif
+    /** Pointer to an array of handles and IDs. */
+    PRTPOLLSETHNDENT    paHandles;
+} RTPOLLSETINTERNAL;
+
+
+
+/**
+ * Common worker for RTPoll and RTPollNoResume
+ */
+static int rtPollNoResumeWorker(RTPOLLSETINTERNAL *pThis, uint64_t MsStart, RTMSINTERVAL cMillies,
+                                uint32_t *pfEvents, uint32_t *pid)
+{
+    int rc;
+
+    /*
+     * Check for special case, RTThreadSleep...
+     */
+    uint32_t const  cHandles = pThis->cHandles;
+    if (cHandles == 0)
+    {
+        if (RT_LIKELY(cMillies != RT_INDEFINITE_WAIT))
+        {
+            rc = RTThreadSleep(cMillies);
+            if (RT_SUCCESS(rc))
+                rc = VERR_TIMEOUT;
+        }
+        else
+            rc = VERR_DEADLOCK;
+        return rc;
+    }
+
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+    /*
+     * Check + prepare the handles before waiting.
+     */
+    uint32_t        fEvents  = 0;
+    bool const      fNoWait  = cMillies == 0;
+    uint32_t        i;
+    for (i = 0; i < cHandles; i++)
+    {
+        switch (pThis->paHandles[i].enmType)
+        {
+            case RTHANDLETYPE_PIPE:
+                fEvents = rtPipePollStart(pThis->paHandles[i].u.hPipe, pThis, pThis->paHandles[i].fEvents,
+                                          pThis->paHandles[i].fFinalEntry, fNoWait);
+                break;
+
+            case RTHANDLETYPE_SOCKET:
+                fEvents = rtSocketPollStart(pThis->paHandles[i].u.hSocket, pThis, pThis->paHandles[i].fEvents,
+                                            pThis->paHandles[i].fFinalEntry, fNoWait);
+                break;
+
+            default:
+                AssertFailed();
+                fEvents = UINT32_MAX;
+                break;
+        }
+        if (fEvents)
+            break;
+    }
+    if (   fEvents
+        || fNoWait)
+    {
+
+        if (pid)
+            *pid = pThis->paHandles[i].id;
+        if (pfEvents)
+            *pfEvents = fEvents;
+        rc = !fEvents
+           ? VERR_TIMEOUT
+           : fEvents != UINT32_MAX
+           ? VINF_SUCCESS
+           : VERR_INTERNAL_ERROR_4;
+
+        /* clean up */
+        if (!fNoWait)
+            while (i-- > 0)
+            {
+                switch (pThis->paHandles[i].enmType)
+                {
+                    case RTHANDLETYPE_PIPE:
+                        rtPipePollDone(pThis->paHandles[i].u.hPipe, pThis->paHandles[i].fEvents,
+                                       pThis->paHandles[i].fFinalEntry, false);
+                        break;
+
+                    case RTHANDLETYPE_SOCKET:
+                        rtSocketPollDone(pThis->paHandles[i].u.hSocket, pThis->paHandles[i].fEvents,
+                                         pThis->paHandles[i].fFinalEntry, false);
+                        break;
+
+                    default:
+                        AssertFailed();
+                        break;
+                }
+            }
+
+        return rc;
+    }
+
+
+    /*
+     * Wait.
+     */
+# ifdef RT_OS_WINDOWS
+    RT_NOREF_PV(MsStart);
+
+    DWORD dwRc = WaitForMultipleObjectsEx(cHandles, pThis->pahNative,
+                                          FALSE /*fWaitAll */,
+                                          cMillies == RT_INDEFINITE_WAIT ? INFINITE : cMillies,
+                                          TRUE /*fAlertable*/);
+    AssertCompile(WAIT_OBJECT_0 == 0);
+    if (dwRc < WAIT_OBJECT_0 + cHandles)
+        rc = VERR_INTERRUPTED;
+    else if (dwRc == WAIT_TIMEOUT)
+        rc = VERR_TIMEOUT;
+    else if (dwRc == WAIT_IO_COMPLETION)
+        rc = VERR_INTERRUPTED;
+    else if (dwRc == WAIT_FAILED)
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+    {
+        AssertMsgFailed(("%u (%#x)\n", dwRc, dwRc));
+        rc = VERR_INTERNAL_ERROR_5;
+    }
+
+# else  /* RT_OS_OS2 */
+    APIRET      orc;
+    ULONG       ulUser   = 0;
+    uint16_t    cSockets = pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets;
+    if (cSockets == 0)
+    {
+        /* Only pipes. */
+        AssertReturn(pThis->cPipes > 0, VERR_INTERNAL_ERROR_2);
+        orc = DosWaitMuxWaitSem(pThis->hmux,
+                                cMillies == RT_INDEFINITE_WAIT ? SEM_INDEFINITE_WAIT : RT_MIN(cMillies, SEM_INDEFINITE_WAIT - 1),
+                                &ulUser);
+        rc = RTErrConvertFromOS2(orc);
+    }
+    else
+    {
+        int *pafdSelect = (int *)alloca(cSockets + 1);
+        if (pThis->cPipes == 0)
+        {
+            /* Only sockets. */
+            memcpy(pafdSelect, pThis->pafdSelect, sizeof(pThis->pafdSelect[0]) * (cSockets + 1));
+            rc = os2_select(pafdSelect, pThis->cReadSockets, pThis->cWriteSockets, pThis->cXcptSockets,
+                            cMillies == RT_INDEFINITE_WAIT ? -1 : (long)RT_MIN(cMillies, LONG_MAX));
+            if (rc > 0)
+                rc = VINF_SUCCESS;
+            else if (rc == 0)
+                rc = VERR_TIMEOUT;
+            else
+                rc = RTErrConvertFromErrno(sock_errno());
+        }
+        else
+        {
+            /* Mix of both - taking the easy way out, not optimal, but whatever... */
+            do
+            {
+                orc = DosWaitMuxWaitSem(pThis->hmux, 8, &ulUser);
+                if (orc != ERROR_TIMEOUT && orc != ERROR_SEM_TIMEOUT)
+                {
+                    rc = RTErrConvertFromOS2(orc);
+                    break;
+                }
+
+                memcpy(pafdSelect, pThis->pafdSelect, sizeof(pThis->pafdSelect[0]) * (cSockets + 1));
+                rc = os2_select(pafdSelect, pThis->cReadSockets, pThis->cWriteSockets, pThis->cXcptSockets, 8);
+                if (rc != 0)
+                {
+                    if (rc > 0)
+                        rc = VINF_SUCCESS;
+                    else
+                        rc = RTErrConvertFromErrno(sock_errno());
+                    break;
+                }
+            } while (cMillies == RT_INDEFINITE_WAIT || RTTimeMilliTS() - MsStart < cMillies);
+        }
+    }
+# endif /* RT_OS_OS2 */
+
+    /*
+     * Get event (if pending) and do wait cleanup.
+     */
+    bool fHarvestEvents = true;
+    for (i = 0; i < cHandles; i++)
+    {
+        fEvents = 0;
+        switch (pThis->paHandles[i].enmType)
+        {
+            case RTHANDLETYPE_PIPE:
+                fEvents = rtPipePollDone(pThis->paHandles[i].u.hPipe, pThis->paHandles[i].fEvents,
+                                         pThis->paHandles[i].fFinalEntry, fHarvestEvents);
+                break;
+
+            case RTHANDLETYPE_SOCKET:
+                fEvents = rtSocketPollDone(pThis->paHandles[i].u.hSocket, pThis->paHandles[i].fEvents,
+                                           pThis->paHandles[i].fFinalEntry, fHarvestEvents);
+                break;
+
+            default:
+                AssertFailed();
+                break;
+        }
+        if (   fEvents
+            && fHarvestEvents)
+        {
+            Assert(fEvents != UINT32_MAX);
+            fHarvestEvents = false;
+            if (pfEvents)
+                *pfEvents = fEvents;
+            if (pid)
+                *pid = pThis->paHandles[i].id;
+            rc = VINF_SUCCESS;
+        }
+    }
+
+#else  /* POSIX */
+
+    RT_NOREF_PV(MsStart);
+
+    /* clear the revents. */
+    uint32_t i = pThis->cHandles;
+    while (i-- > 0)
+        pThis->paPollFds[i].revents = 0;
+
+    rc = poll(&pThis->paPollFds[0], pThis->cHandles,
+              cMillies == RT_INDEFINITE_WAIT || cMillies >= INT_MAX
+              ? -1
+              : (int)cMillies);
+    if (rc == 0)
+        return VERR_TIMEOUT;
+    if (rc < 0)
+        return RTErrConvertFromErrno(errno);
+    for (i = 0; i < pThis->cHandles; i++)
+        if (pThis->paPollFds[i].revents)
+        {
+            if (pfEvents)
+            {
+                *pfEvents = 0;
+                if (pThis->paPollFds[i].revents & (POLLIN
+# ifdef POLLRDNORM
+                                                   | POLLRDNORM     /* just in case */
+# endif
+# ifdef POLLRDBAND
+                                                   | POLLRDBAND     /* ditto */
+# endif
+# ifdef POLLPRI
+                                                   | POLLPRI        /* ditto */
+# endif
+# ifdef POLLMSG
+                                                   | POLLMSG        /* ditto */
+# endif
+# ifdef POLLWRITE
+                                                   | POLLWRITE       /* ditto */
+# endif
+# ifdef POLLEXTEND
+                                                   | POLLEXTEND      /* ditto */
+# endif
+                                                   )
+                   )
+                    *pfEvents |= RTPOLL_EVT_READ;
+
+                if (pThis->paPollFds[i].revents & (POLLOUT
+# ifdef POLLWRNORM
+                                                   | POLLWRNORM     /* just in case */
+# endif
+# ifdef POLLWRBAND
+                                                   | POLLWRBAND     /* ditto */
+# endif
+                                                   )
+                   )
+                    *pfEvents |= RTPOLL_EVT_WRITE;
+
+                if (pThis->paPollFds[i].revents & (POLLERR | POLLHUP | POLLNVAL
+# ifdef POLLRDHUP
+                                                   | POLLRDHUP
+# endif
+                                                   )
+                   )
+                    *pfEvents |= RTPOLL_EVT_ERROR;
+
+# if defined(RT_OS_SOLARIS)
+                /* Solaris does not return POLLHUP for sockets, just POLLIN.  Check if a
+                   POLLIN should also have RTPOLL_EVT_ERROR set or not, so we present a
+                   behaviour more in line with linux and BSDs.  Note that this will not
+                   help is only RTPOLL_EVT_ERROR was requested, that will require
+                   extending this hack quite a bit further (restart poll):  */
+                if (   *pfEvents == RTPOLL_EVT_READ
+                    && pThis->paHandles[i].enmType == RTHANDLETYPE_SOCKET)
+                {
+                    uint8_t abBuf[64];
+                    ssize_t rcRecv = recv(pThis->paPollFds[i].fd, abBuf, sizeof(abBuf), MSG_PEEK | MSG_DONTWAIT);
+                    if (rcRecv == 0)
+                        *pfEvents |= RTPOLL_EVT_ERROR;
+                }
+# endif
+            }
+            if (pid)
+                *pid = pThis->paHandles[i].id;
+            return VINF_SUCCESS;
+        }
+
+    AssertFailed();
+    RTThreadYield();
+    rc = VERR_INTERRUPTED;
+
+#endif /* POSIX */
+
+    return rc;
+}
+
+
+RTDECL(int) RTPoll(RTPOLLSET hPollSet, RTMSINTERVAL cMillies, uint32_t *pfEvents, uint32_t *pid)
+{
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrNull(pfEvents);
+    AssertPtrNull(pid);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    int rc;
+    if (cMillies == RT_INDEFINITE_WAIT || cMillies == 0)
+    {
+        do rc = rtPollNoResumeWorker(pThis, 0, cMillies, pfEvents, pid);
+        while (rc == VERR_INTERRUPTED);
+    }
+    else
+    {
+        uint64_t MsStart = RTTimeMilliTS();
+        rc = rtPollNoResumeWorker(pThis, MsStart, cMillies, pfEvents, pid);
+        while (RT_UNLIKELY(rc == VERR_INTERRUPTED))
+        {
+            if (RTTimeMilliTS() - MsStart >= cMillies)
+            {
+                rc = VERR_TIMEOUT;
+                break;
+            }
+            rc = rtPollNoResumeWorker(pThis, MsStart, cMillies, pfEvents, pid);
+        }
+    }
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+
+    return rc;
+}
+
+
+RTDECL(int) RTPollNoResume(RTPOLLSET hPollSet, RTMSINTERVAL cMillies, uint32_t *pfEvents, uint32_t *pid)
+{
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrNull(pfEvents);
+    AssertPtrNull(pid);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    int rc;
+    if (cMillies == RT_INDEFINITE_WAIT || cMillies == 0)
+        rc = rtPollNoResumeWorker(pThis, 0, cMillies, pfEvents, pid);
+    else
+        rc = rtPollNoResumeWorker(pThis, RTTimeMilliTS(), cMillies, pfEvents, pid);
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+
+    return rc;
+}
+
+
+RTDECL(int) RTPollSetCreate(PRTPOLLSET phPollSet)
+{
+    AssertPtrReturn(phPollSet, VERR_INVALID_POINTER);
+    RTPOLLSETINTERNAL *pThis = (RTPOLLSETINTERNAL *)RTMemAlloc(sizeof(RTPOLLSETINTERNAL));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+
+    pThis->fBusy                = false;
+    pThis->cHandles             = 0;
+    pThis->cHandlesAllocated    = 0;
+#ifdef RT_OS_WINDOWS
+    pThis->pahNative            = NULL;
+#elif defined(RT_OS_OS2)
+    pThis->hmux                 = NULLHANDLE;
+    APIRET orc = DosCreateMuxWaitSem(NULL, &pThis->hmux, 0, NULL, DCMW_WAIT_ANY);
+    if (orc != NO_ERROR)
+    {
+        RTMemFree(pThis);
+        return RTErrConvertFromOS2(orc);
+    }
+    pThis->pafdSelect           = NULL;
+    pThis->cReadSockets           = 0;
+    pThis->cWriteSockets          = 0;
+    pThis->cXcptSockets           = 0;
+    pThis->cPipes               = 0;
+    pThis->pahNative            = NULL;
+#else
+    pThis->paPollFds            = NULL;
+#endif
+    pThis->paHandles            = NULL;
+    pThis->u32Magic             = RTPOLLSET_MAGIC;
+
+    *phPollSet = pThis;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTPollSetDestroy(RTPOLLSET hPollSet)
+{
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    if (pThis == NIL_RTPOLLSET)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    ASMAtomicWriteU32(&pThis->u32Magic, ~RTPOLLSET_MAGIC);
+#ifdef RT_OS_WINDOWS
+    RTMemFree(pThis->pahNative);
+    pThis->pahNative = NULL;
+#elif defined(RT_OS_OS2)
+    DosCloseMuxWaitSem(pThis->hmux);
+    pThis->hmux = NULLHANDLE;
+    RTMemFree(pThis->pafdSelect);
+    pThis->pafdSelect = NULL;
+    RTMemFree(pThis->pahNative);
+    pThis->pahNative = NULL;
+#else
+    RTMemFree(pThis->paPollFds);
+    pThis->paPollFds = NULL;
+#endif
+    RTMemFree(pThis->paHandles);
+    pThis->paHandles = NULL;
+    RTMemFree(pThis);
+
+    return VINF_SUCCESS;
+}
+
+#ifdef RT_OS_OS2
+
+/**
+ * Checks if @a fd is in the specific socket subset.
+ *
+ * @returns true / false.
+ * @param   pThis       The poll set instance.
+ * @param   iStart      The index to start at.
+ * @param   cFds        The number of sockets to check.
+ * @param   fd          The socket to look for.
+ */
+static bool rtPollSetOs2IsSocketInSet(RTPOLLSETINTERNAL *pThis, uint16_t iStart, uint16_t cFds, int fd)
+{
+    int const *pfd = pThis->pafdSelect + iStart;
+    while (cFds-- > 0)
+    {
+        if (*pfd == fd)
+            return true;
+        pfd++;
+    }
+    return false;
+}
+
+
+/**
+ * Removes a socket from a select template subset.
+ *
+ * @param   pThis       The poll set instance.
+ * @param   iStart      The index to start at.
+ * @param   pcSubSet    The subset counter to decrement.
+ * @param   fd          The socket to remove.
+ */
+static void rtPollSetOs2RemoveSocket(RTPOLLSETINTERNAL *pThis, uint16_t iStart, uint16_t *pcFds, int fd)
+{
+    uint16_t cFds = *pcFds;
+    while (cFds-- > 0)
+    {
+        if (pThis->pafdSelect[iStart] == fd)
+            break;
+        iStart++;
+    }
+    AssertReturnVoid(iStart != UINT16_MAX);
+
+    /* Note! We keep a -1 entry at the end of the set, thus the + 1. */
+    memmove(&pThis->pafdSelect[iStart],
+            &pThis->pafdSelect[iStart + 1],
+            pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets + 1 - 1 - iStart);
+    *pcFds -= 1;
+
+    Assert(pThis->pafdSelect[pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets] == -1);
+}
+
+
+/**
+ * Adds a socket to a select template subset.
+ *
+ * @param   pThis       The poll set instance.
+ * @param   iInsert     The insertion point.
+ *                      ASSUMED to be at the end of the subset.
+ * @param   pcSubSet    The subset counter to increment.
+ * @param   fd          The socket to add.
+ */
+static void rtPollSetOs2AddSocket(RTPOLLSETINTERNAL *pThis, uint16_t iInsert, uint16_t *pcFds, int fd)
+{
+    Assert(!rtPollSetOs2IsSocketInSet(pThis, iInsert - *pcFds, *pcFds, fd));
+
+    /* Note! We keep a -1 entry at the end of the set, thus the + 1. */
+    memmove(&pThis->pafdSelect[iInsert + 1],
+            &pThis->pafdSelect[iInsert],
+            pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets + 1 - iInsert);
+    pThis->pafdSelect[iInsert] = fd;
+    *pcFds += 1;
+
+    Assert(pThis->pafdSelect[pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets] == -1);
+}
+
+
+/**
+ * OS/2 specific RTPollSetAdd worker.
+ *
+ * @returns IPRT status code.
+ * @param   pThis       The poll set instance.
+ * @param   i           The index of the new handle (not committed).
+ * @param   fEvents     The events to poll for.
+ */
+static int rtPollSetOs2Add(RTPOLLSETINTERNAL *pThis, unsigned i, uint32_t fEvents)
+{
+    if (pThis->paHandles[i].enmType == RTHANDLETYPE_SOCKET)
+    {
+        int const fdSocket = pThis->pahNative[i];
+        if (   (fEvents & RTPOLL_EVT_READ)
+            && rtPollSetOs2IsSocketInSet(pThis, 0, pThis->cReadSockets, fdSocket))
+            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets, &pThis->cReadSockets, fdSocket);
+
+        if (   (fEvents & RTPOLL_EVT_WRITE)
+            && rtPollSetOs2IsSocketInSet(pThis, pThis->cReadSockets, pThis->cWriteSockets, fdSocket))
+            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets, &pThis->cWriteSockets, fdSocket);
+
+        if (   (fEvents & RTPOLL_EVT_ERROR)
+            && rtPollSetOs2IsSocketInSet(pThis, pThis->cReadSockets + pThis->cWriteSockets, pThis->cXcptSockets, fdSocket))
+            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets,
+                                  &pThis->cXcptSockets, fdSocket);
+    }
+    else if (pThis->paHandles[i].enmType == RTHANDLETYPE_PIPE)
+    {
+        SEMRECORD Rec = { (HSEM)pThis->pahNative[i], pThis->paHandles[i].id };
+        APIRET orc = DosAddMuxWaitSem(pThis->hmux, &Rec);
+        if (orc != NO_ERROR && orc != ERROR_DUPLICATE_HANDLE)
+            return RTErrConvertFromOS2(orc);
+        pThis->cPipes++;
+    }
+    else
+        AssertFailedReturn(VERR_INTERNAL_ERROR_2);
+    return VINF_SUCCESS;
+}
+
+#endif /* RT_OS_OS2 */
+
+/**
+ * Grows the poll set.
+ *
+ * @returns VINF_SUCCESS or VERR_NO_MEMORY.
+ * @param   pThis               The poll set instance.
+ * @param   cHandlesNew         The new poll set size.
+ */
+static int rtPollSetGrow(RTPOLLSETINTERNAL *pThis, uint32_t cHandlesNew)
+{
+    Assert(cHandlesNew > pThis->cHandlesAllocated);
+
+    /* The common array. */
+    void *pvNew = RTMemRealloc(pThis->paHandles, cHandlesNew * sizeof(pThis->paHandles[0]));
+    if (!pvNew)
+        return VERR_NO_MEMORY;
+    pThis->paHandles = (PRTPOLLSETHNDENT)pvNew;
+
+
+    /* OS specific handles */
+#if defined(RT_OS_WINDOWS)
+    pvNew = RTMemRealloc(pThis->pahNative, cHandlesNew * sizeof(pThis->pahNative[0]));
+    if (!pvNew)
+        return VERR_NO_MEMORY;
+    pThis->pahNative  = (HANDLE *)pvNew;
+
+#elif defined(RT_OS_OS2)
+    pvNew = RTMemRealloc(pThis->pahNative, cHandlesNew * sizeof(pThis->pahNative[0]));
+    if (!pvNew)
+        return VERR_NO_MEMORY;
+    pThis->pahNative  = (PRTHCINTPTR)pvNew;
+
+    pvNew = RTMemRealloc(pThis->pafdSelect, (cHandlesNew * 3 + 1) * sizeof(pThis->pafdSelect[0]));
+    if (!pvNew)
+        return VERR_NO_MEMORY;
+    pThis->pafdSelect  = (int *)pvNew;
+    if (pThis->cHandlesAllocated == 0)
+        pThis->pafdSelect[0] = -1;
+
+#else
+    pvNew = RTMemRealloc(pThis->paPollFds, cHandlesNew * sizeof(pThis->paPollFds[0]));
+    if (!pvNew)
+        return VERR_NO_MEMORY;
+    pThis->paPollFds  = (struct pollfd *)pvNew;
+
+#endif
+
+    pThis->cHandlesAllocated = (uint16_t)cHandlesNew;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTPollSetAdd(RTPOLLSET hPollSet, PCRTHANDLE pHandle, uint32_t fEvents, uint32_t id)
+{
+    /*
+     * Validate the input (tedious).
+     */
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fEvents & ~RTPOLL_EVT_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(fEvents, VERR_INVALID_PARAMETER);
+    AssertReturn(id != UINT32_MAX, VERR_INVALID_PARAMETER);
+
+    if (!pHandle)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pHandle, VERR_INVALID_POINTER);
+    AssertReturn(pHandle->enmType > RTHANDLETYPE_INVALID && pHandle->enmType < RTHANDLETYPE_END, VERR_INVALID_PARAMETER);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+
+    int             rc       = VINF_SUCCESS;
+    RTHCINTPTR      hNative  = -1;
+    RTHANDLEUNION   uh;
+    uh.uInt = 0;
+    switch (pHandle->enmType)
+    {
+        case RTHANDLETYPE_PIPE:
+            uh.hPipe = pHandle->u.hPipe;
+            if (uh.hPipe == NIL_RTPIPE)
+                return VINF_SUCCESS;
+            rc = rtPipePollGetHandle(uh.hPipe, fEvents, &hNative);
+            break;
+
+        case RTHANDLETYPE_SOCKET:
+            uh.hSocket = pHandle->u.hSocket;
+            if (uh.hSocket == NIL_RTSOCKET)
+                return VINF_SUCCESS;
+            rc = rtSocketPollGetHandle(uh.hSocket, fEvents, &hNative);
+            break;
+
+        case RTHANDLETYPE_FILE:
+            AssertMsgFailed(("Files are always ready for reading/writing and thus not pollable. Use native APIs for special devices.\n"));
+            rc = VERR_POLL_HANDLE_NOT_POLLABLE;
+            break;
+
+        case RTHANDLETYPE_THREAD:
+            AssertMsgFailed(("Thread handles are currently not pollable\n"));
+            rc = VERR_POLL_HANDLE_NOT_POLLABLE;
+            break;
+
+        default:
+            AssertMsgFailed(("\n"));
+            rc = VERR_POLL_HANDLE_NOT_POLLABLE;
+            break;
+    }
+    if (RT_SUCCESS(rc))
+    {
+        AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+        uint32_t const i = pThis->cHandles;
+
+        /* Check that the handle ID doesn't exist already. */
+        uint32_t iPrev = UINT32_MAX;
+        uint32_t j     = i;
+        while (j-- > 0)
+        {
+            if (pThis->paHandles[j].id == id)
+            {
+                rc = VERR_POLL_HANDLE_ID_EXISTS;
+                break;
+            }
+            if (   pThis->paHandles[j].enmType == pHandle->enmType
+                && pThis->paHandles[j].u.uInt  == uh.uInt)
+                iPrev = j;
+        }
+
+        /* Check that we won't overflow the poll set now. */
+        if (    RT_SUCCESS(rc)
+            &&  i + 1 > RTPOLL_SET_MAX)
+            rc = VERR_POLL_SET_IS_FULL;
+
+        /* Grow the tables if necessary. */
+        if (RT_SUCCESS(rc) && i + 1 > pThis->cHandlesAllocated)
+            rc = rtPollSetGrow(pThis, pThis->cHandlesAllocated + 32);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Add the handles to the two parallel arrays.
+             */
+#ifdef RT_OS_WINDOWS
+            pThis->pahNative[i]             = (HANDLE)hNative;
+#elif defined(RT_OS_OS2)
+            pThis->pahNative[i]             = hNative;
+#else
+            pThis->paPollFds[i].fd          = (int)hNative;
+            pThis->paPollFds[i].revents     = 0;
+            pThis->paPollFds[i].events      = 0;
+            if (fEvents & RTPOLL_EVT_READ)
+                pThis->paPollFds[i].events |= POLLIN;
+            if (fEvents & RTPOLL_EVT_WRITE)
+                pThis->paPollFds[i].events |= POLLOUT;
+            if (fEvents & RTPOLL_EVT_ERROR)
+# ifdef RT_OS_DARWIN
+                pThis->paPollFds[i].events |= POLLERR | POLLHUP;
+# else
+                pThis->paPollFds[i].events |= POLLERR;
+# endif
+#endif
+            pThis->paHandles[i].enmType     = pHandle->enmType;
+            pThis->paHandles[i].u           = uh;
+            pThis->paHandles[i].id          = id;
+            pThis->paHandles[i].fEvents     = fEvents;
+            pThis->paHandles[i].fFinalEntry = true;
+
+            if (iPrev != UINT32_MAX)
+            {
+                Assert(pThis->paHandles[iPrev].fFinalEntry);
+                pThis->paHandles[iPrev].fFinalEntry = false;
+            }
+
+            /*
+             * Validations and OS specific updates.
+             */
+#ifdef RT_OS_WINDOWS
+            /* none */
+#elif defined(RT_OS_OS2)
+            rc = rtPollSetOs2Add(pThis, i, fEvents);
+#else  /* POSIX */
+            if (poll(&pThis->paPollFds[i], 1, 0) < 0)
+            {
+                rc = RTErrConvertFromErrno(errno);
+                pThis->paPollFds[i].fd = -1;
+            }
+#endif /* POSIX */
+
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Commit it to the set.
+                 */
+                pThis->cHandles++; Assert(pThis->cHandles == i + 1);
+                rc = VINF_SUCCESS;
+            }
+        }
+    }
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+    return rc;
+}
+
+
+RTDECL(int) RTPollSetRemove(RTPOLLSET hPollSet, uint32_t id)
+{
+    /*
+     * Validate the input.
+     */
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(id != UINT32_MAX, VERR_INVALID_PARAMETER);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    int         rc = VERR_POLL_HANDLE_ID_NOT_FOUND;
+    uint32_t    i  = pThis->cHandles;
+    while (i-- > 0)
+        if (pThis->paHandles[i].id == id)
+        {
+            /* Save some details for the duplicate searching. */
+            bool const          fFinalEntry     = pThis->paHandles[i].fFinalEntry;
+            RTHANDLETYPE const  enmType         = pThis->paHandles[i].enmType;
+            RTHANDLEUNION const uh              = pThis->paHandles[i].u;
+#ifdef RT_OS_OS2
+            uint32_t            fRemovedEvents  = pThis->paHandles[i].fEvents;
+            RTHCINTPTR const    hNative         = pThis->pahNative[i];
+#endif
+
+            /* Remove the entry. */
+            pThis->cHandles--;
+            size_t const cToMove = pThis->cHandles - i;
+            if (cToMove)
+            {
+                memmove(&pThis->paHandles[i], &pThis->paHandles[i + 1], cToMove * sizeof(pThis->paHandles[i]));
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+                memmove(&pThis->pahNative[i], &pThis->pahNative[i + 1], cToMove * sizeof(pThis->pahNative[i]));
+#else
+                memmove(&pThis->paPollFds[i], &pThis->paPollFds[i + 1], cToMove * sizeof(pThis->paPollFds[i]));
+#endif
+            }
+
+            /* Check for duplicate and set the fFinalEntry flag. */
+            if (fFinalEntry)
+                while (i-- > 0)
+                    if (   pThis->paHandles[i].u.uInt  == uh.uInt
+                        && pThis->paHandles[i].enmType == enmType)
+                    {
+                        Assert(!pThis->paHandles[i].fFinalEntry);
+                        pThis->paHandles[i].fFinalEntry = true;
+                        break;
+                    }
+
+#ifdef RT_OS_OS2
+            /*
+             * Update OS/2 wait structures.
+             */
+            uint32_t fNewEvents = 0;
+            i = pThis->cHandles;
+            while (i-- > 0)
+                if (   pThis->paHandles[i].u.uInt  == uh.uInt
+                    && pThis->paHandles[i].enmType == enmType)
+                    fNewEvents |= pThis->paHandles[i].fEvents;
+            if (enmType == RTHANDLETYPE_PIPE)
+            {
+                pThis->cPipes--;
+                if (fNewEvents == 0)
+                {
+                    APIRET orc = DosDeleteMuxWaitSem(pThis->hmux, (HSEM)hNative);
+                    AssertMsg(orc == NO_ERROR, ("%d\n", orc));
+                }
+            }
+            else if (   fNewEvents != (fNewEvents | fRemovedEvents)
+                     && enmType == RTHANDLETYPE_SOCKET)
+            {
+                fRemovedEvents = fNewEvents ^ (fNewEvents | fRemovedEvents);
+                if (fRemovedEvents & RTPOLL_EVT_ERROR)
+                    rtPollSetOs2RemoveSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets, &pThis->cXcptSockets, (int)hNative);
+                if (fRemovedEvents & RTPOLL_EVT_WRITE)
+                    rtPollSetOs2RemoveSocket(pThis, pThis->cReadSockets, &pThis->cWriteSockets, (int)hNative);
+                if (fRemovedEvents & RTPOLL_EVT_READ)
+                    rtPollSetOs2RemoveSocket(pThis, 0, &pThis->cReadSockets, (int)hNative);
+            }
+#endif /* RT_OS_OS2 */
+            rc = VINF_SUCCESS;
+            break;
+        }
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+    return rc;
+}
+
+
+RTDECL(int) RTPollSetQueryHandle(RTPOLLSET hPollSet, uint32_t id, PRTHANDLE pHandle)
+{
+    /*
+     * Validate the input.
+     */
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(id != UINT32_MAX, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pHandle, VERR_INVALID_POINTER);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    int         rc = VERR_POLL_HANDLE_ID_NOT_FOUND;
+    uint32_t    i  = pThis->cHandles;
+    while (i-- > 0)
+        if (pThis->paHandles[i].id == id)
+        {
+            if (pHandle)
+            {
+                pHandle->enmType = pThis->paHandles[i].enmType;
+                pHandle->u       = pThis->paHandles[i].u;
+            }
+            rc = VINF_SUCCESS;
+            break;
+        }
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTPollSetGetCount(RTPOLLSET hPollSet)
+{
+    /*
+     * Validate the input.
+     */
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, UINT32_MAX);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), UINT32_MAX);
+    uint32_t cHandles = pThis->cHandles;
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+
+    return cHandles;
+}
+
+RTDECL(int) RTPollSetEventsChange(RTPOLLSET hPollSet, uint32_t id, uint32_t fEvents)
+{
+    /*
+     * Validate the input.
+     */
+    RTPOLLSETINTERNAL *pThis = hPollSet;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPOLLSET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(id != UINT32_MAX, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fEvents & ~RTPOLL_EVT_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(fEvents, VERR_INVALID_PARAMETER);
+
+    /*
+     * Set the busy flag and do the job.
+     */
+    AssertReturn(ASMAtomicCmpXchgBool(&pThis->fBusy, true,  false), VERR_CONCURRENT_ACCESS);
+
+    int         rc = VERR_POLL_HANDLE_ID_NOT_FOUND;
+    uint32_t    i  = pThis->cHandles;
+    while (i-- > 0)
+        if (pThis->paHandles[i].id == id)
+        {
+            if (pThis->paHandles[i].fEvents != fEvents)
+            {
+#if defined(RT_OS_WINDOWS)
+                /*nothing*/
+#elif defined(RT_OS_OS2)
+                if (pThis->paHandles[i].enmType == RTHANDLETYPE_SOCKET)
+                {
+                    uint32_t fOldEvents = 0;
+                    uint32_t j          = pThis->cHandles;
+                    while (j-- > 0)
+                        if (   pThis->paHandles[j].enmType == RTHANDLETYPE_SOCKET
+                            && pThis->paHandles[j].u.uInt  == pThis->paHandles[i].u.uInt
+                            && j != i)
+                            fOldEvents |= pThis->paHandles[j].fEvents;
+                    uint32_t fNewEvents = fOldEvents | fEvents;
+                    fOldEvents |= pThis->paHandles[i].fEvents;
+                    if (fOldEvents != fEvents)
+                    {
+                        int const       fdSocket = pThis->pahNative[i];
+                        uint32_t const  fChangedEvents = fOldEvents ^ fNewEvents;
+
+                        if ((fChangedEvents & RTPOLL_EVT_READ) && (fNewEvents & RTPOLL_EVT_READ))
+                            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets, &pThis->cReadSockets, fdSocket);
+                        else if (fChangedEvents & RTPOLL_EVT_READ)
+                            rtPollSetOs2RemoveSocket(pThis, 0, &pThis->cReadSockets, fdSocket);
+
+                        if ((fChangedEvents & RTPOLL_EVT_WRITE) && (fNewEvents & RTPOLL_EVT_WRITE))
+                            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets,
+                                                  &pThis->cWriteSockets, fdSocket);
+                        else if (fChangedEvents & RTPOLL_EVT_WRITE)
+                            rtPollSetOs2RemoveSocket(pThis, pThis->cReadSockets, &pThis->cWriteSockets, fdSocket);
+
+                        if ((fChangedEvents & RTPOLL_EVT_ERROR) && (fNewEvents & RTPOLL_EVT_ERROR))
+                            rtPollSetOs2AddSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets + pThis->cXcptSockets,
+                                                  &pThis->cXcptSockets, fdSocket);
+                        else if (fChangedEvents & RTPOLL_EVT_ERROR)
+                            rtPollSetOs2RemoveSocket(pThis, pThis->cReadSockets + pThis->cWriteSockets, &pThis->cXcptSockets,
+                                                     fdSocket);
+                    }
+                }
+#else
+                pThis->paPollFds[i].events  = 0;
+                if (fEvents & RTPOLL_EVT_READ)
+                    pThis->paPollFds[i].events |= POLLIN;
+                if (fEvents & RTPOLL_EVT_WRITE)
+                    pThis->paPollFds[i].events |= POLLOUT;
+                if (fEvents & RTPOLL_EVT_ERROR)
+                    pThis->paPollFds[i].events |= POLLERR;
+#endif
+                pThis->paHandles[i].fEvents = fEvents;
+            }
+            rc = VINF_SUCCESS;
+            break;
+        }
+
+    ASMAtomicWriteBool(&pThis->fBusy, false);
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/Makefile.kup b/src/VBox/Runtime/r3/posix/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/Makefile.kup
diff --git a/src/VBox/Runtime/r3/posix/RTFileQueryFsSizes-posix.cpp b/src/VBox/Runtime/r3/posix/RTFileQueryFsSizes-posix.cpp
new file mode 100644
index 00000000..886c3844
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTFileQueryFsSizes-posix.cpp
@@ -0,0 +1,78 @@
+/* $Id: RTFileQueryFsSizes-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, RTFileFsQuerySizes, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/statvfs.h>
+
+#include <iprt/file.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/string.h>
+
+
+RTR3DECL(int) RTFileQueryFsSizes(RTFILE hFile, PRTFOFF pcbTotal, RTFOFF *pcbFree,
+                                 uint32_t *pcbBlock, uint32_t *pcbSector)
+{
+    struct statvfs StatVFS;
+    RT_ZERO(StatVFS);
+    if (fstatvfs(RTFileToNative(hFile), &StatVFS))
+        return RTErrConvertFromErrno(errno);
+
+    /*
+     * Calc the returned values.
+     */
+    if (pcbTotal)
+        *pcbTotal = (RTFOFF)StatVFS.f_blocks * StatVFS.f_frsize;
+    if (pcbFree)
+        *pcbFree = (RTFOFF)StatVFS.f_bavail * StatVFS.f_frsize;
+    if (pcbBlock)
+        *pcbBlock = StatVFS.f_frsize;
+    /* no idea how to get the sector... */
+    if (pcbSector)
+        *pcbSector = 512;
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTFileSetAllocationSize-posix.cpp b/src/VBox/Runtime/r3/posix/RTFileSetAllocationSize-posix.cpp
new file mode 100644
index 00000000..534754ac
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTFileSetAllocationSize-posix.cpp
@@ -0,0 +1,87 @@
+/* $Id: RTFileSetAllocationSize-posix.cpp $ */
+/** @file
+ * IPRT - RTFileSetAllocationSize, linux implementation.
+ */
+
+/*
+ * Copyright (C) 2016-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/file.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+/**
+ * The posix_fallocate() method.
+ */
+typedef int (*PFNPOSIXFALLOCATE) (int iFd, off_t offStart, off_t cb);
+
+RTDECL(int) RTFileSetAllocationSize(RTFILE hFile, uint64_t cbSize, uint32_t fFlags)
+{
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTFILE_ALLOC_SIZE_F_VALID), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(sizeof(off_t) >= sizeof(cbSize) ||  RT_HIDWORD(cbSize) == 0,
+                    ("64-bit filesize not supported! cbSize=%lld\n", cbSize),
+                    VERR_NOT_SUPPORTED);
+
+    if (fFlags & RTFILE_ALLOC_SIZE_F_KEEP_SIZE)
+        return VERR_NOT_SUPPORTED;
+
+    int rc = VINF_SUCCESS;
+    PFNPOSIXFALLOCATE pfnPosixFAllocate = (PFNPOSIXFALLOCATE)(uintptr_t)dlsym(RTLD_DEFAULT, "posix_fallocate");
+    if (RT_VALID_PTR(pfnPosixFAllocate))
+    {
+        int rcPosix = pfnPosixFAllocate(RTFileToNative(hFile), 0, cbSize);
+        if (rcPosix != 0)
+        {
+            if (errno == EOPNOTSUPP)
+                rc = VERR_NOT_SUPPORTED;
+            else
+                rc = RTErrConvertFromErrno(errno);
+        }
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTFileSetAllocationSize);
diff --git a/src/VBox/Runtime/r3/posix/RTHandleGetStandard-posix.cpp b/src/VBox/Runtime/r3/posix/RTHandleGetStandard-posix.cpp
new file mode 100644
index 00000000..30e54331
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTHandleGetStandard-posix.cpp
@@ -0,0 +1,144 @@
+/* $Id: RTHandleGetStandard-posix.cpp $ */
+/** @file
+ * IPRT - RTHandleGetStandard, POSIX.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#ifdef _MSC_VER
+# include <io.h>
+#else
+# include <unistd.h>
+#endif
+
+#include "internal/iprt.h"
+#include <iprt/handle.h>
+
+#include <iprt/file.h>
+#include <iprt/pipe.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+
+#include "internal/socket.h"
+
+
+
+RTDECL(int) RTHandleGetStandard(RTHANDLESTD enmStdHandle, bool fLeaveOpen, PRTHANDLE ph)
+{
+    /*
+     * Validate and convert input.
+     */
+    AssertPtrReturn(ph, VERR_INVALID_POINTER);
+    int fd;
+    switch (enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:  fd = 0; break;
+        case RTHANDLESTD_OUTPUT: fd = 1; break;
+        case RTHANDLESTD_ERROR:  fd = 2; break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Is the requested descriptor valid and which IPRT handle type does it
+     * best map on to?
+     */
+    struct stat st;
+    int rc = fstat(fd, &st);
+    if (rc == -1)
+        return RTErrConvertFromErrno(errno);
+
+    rc = fcntl(fd, F_GETFD, 0);
+    if (rc == -1)
+        return RTErrConvertFromErrno(errno);
+    bool const fInherit = !(rc & FD_CLOEXEC);
+
+    RTHANDLE h;
+    if (S_ISREG(st.st_mode))
+        h.enmType = RTHANDLETYPE_FILE;
+    else if (   S_ISFIFO(st.st_mode)
+             || (st.st_mode == 0 && st.st_nlink == 0 /*see bugs on bsd manpage*/))
+        h.enmType = RTHANDLETYPE_PIPE;
+    else if (S_ISSOCK(st.st_mode))
+    {
+        /** @todo check if it's really a socket... IIRC some OSes reports
+         *        anonymouse pips as sockets. */
+        h.enmType = RTHANDLETYPE_SOCKET;
+    }
+#if 0 /** @todo re-enable this when the VFS pipe has been coded up. */
+    else if (isatty(fd))
+        h.enmType = RTHANDLETYPE_PIPE;
+#endif
+    else
+        h.enmType = RTHANDLETYPE_FILE;
+
+    /*
+     * Create the IPRT handle.
+     */
+    switch (h.enmType)
+    {
+        case RTHANDLETYPE_FILE:
+            /** @todo fLeaveOpen   */
+            rc = RTFileFromNative(&h.u.hFile, fd);
+            break;
+
+        case RTHANDLETYPE_PIPE:
+            rc = RTPipeFromNative(&h.u.hPipe, fd,
+                                    (enmStdHandle == RTHANDLESTD_INPUT ? RTPIPE_N_READ : RTPIPE_N_WRITE)
+                                  | (fInherit ? RTPIPE_N_INHERIT : 0)
+                                  | (fLeaveOpen ? RTPIPE_N_LEAVE_OPEN : 0));
+            break;
+
+        case RTHANDLETYPE_SOCKET:
+            rc = rtSocketCreateForNative(&h.u.hSocket, fd, fLeaveOpen);
+            break;
+
+        default: /* shut up gcc */
+            return VERR_INTERNAL_ERROR;
+    }
+
+    if (RT_SUCCESS(rc))
+        *ph = h;
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTMemProtect-posix.cpp b/src/VBox/Runtime/r3/posix/RTMemProtect-posix.cpp
new file mode 100644
index 00000000..41400a87
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTMemProtect-posix.cpp
@@ -0,0 +1,105 @@
+/* $Id: RTMemProtect-posix.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/param.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+#include <errno.h>
+#include <sys/mman.h>
+
+
+RTDECL(int) RTMemProtect(void *pv, size_t cb, unsigned fProtect) RT_NO_THROW_DEF
+{
+    /*
+     * Validate input.
+     */
+    if (cb == 0)
+    {
+        AssertMsgFailed(("!cb\n"));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (fProtect & ~(RTMEM_PROT_NONE | RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC))
+    {
+        AssertMsgFailed(("fProtect=%#x\n", fProtect));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Convert the flags.
+     */
+    int fProt;
+#if     RTMEM_PROT_NONE  == PROT_NONE \
+    &&  RTMEM_PROT_READ  == PROT_READ \
+    &&  RTMEM_PROT_WRITE == PROT_WRITE \
+    &&  RTMEM_PROT_EXEC  == PROT_EXEC
+    fProt = fProtect;
+#else
+    Assert(!RTMEM_PROT_NONE);
+    if (!fProtect)
+        fProt = PROT_NONE;
+    else
+    {
+        fProt = 0;
+        if (fProtect & RTMEM_PROT_READ)
+            fProt |= PROT_READ;
+        if (fProtect & RTMEM_PROT_WRITE)
+            fProt |= PROT_WRITE;
+        if (fProtect & RTMEM_PROT_EXEC)
+            fProt |= PROT_EXEC;
+    }
+#endif
+
+    /*
+     * Align the request.
+     */
+    cb += (uintptr_t)pv & PAGE_OFFSET_MASK;
+    pv = (void *)((uintptr_t)pv & ~PAGE_OFFSET_MASK);
+
+    /*
+     * Change the page attributes.
+     */
+    int rc = mprotect(pv, cb, fProt);
+    if (!rc)
+        return rc;
+    return RTErrConvertFromErrno(errno);
+}
diff --git a/src/VBox/Runtime/r3/posix/RTMpGetCount-posix.cpp b/src/VBox/Runtime/r3/posix/RTMpGetCount-posix.cpp
new file mode 100644
index 00000000..f48d6f98
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTMpGetCount-posix.cpp
@@ -0,0 +1,89 @@
+/* $Id: RTMpGetCount-posix.cpp $ */
+/** @file
+ * IPRT - RTMpGetCount, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/mp.h>
+#include <iprt/assert.h>
+
+#include <unistd.h>
+#if !defined(RT_OS_SOLARIS)
+# include <sys/sysctl.h>
+#endif
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    /*
+     * The sysconf way (linux and others).
+     */
+#if defined(_SC_NPROCESSORS_MAX) || defined(_SC_NPROCESSORS_CONF) || defined(_SC_NPROCESSORS_ONLN)
+    int cCpusSC = -1;
+# ifdef _SC_NPROCESSORS_MAX
+    int cMax = sysconf(_SC_NPROCESSORS_MAX);
+    cCpusSC = RT_MAX(cCpusSC, cMax);
+# endif
+# ifdef _SC_NPROCESSORS_CONF
+    int cConf = sysconf(_SC_NPROCESSORS_CONF);
+    cCpusSC = RT_MAX(cCpusSC, cConf);
+# endif
+# ifdef _SC_NPROCESSORS_ONLN
+    int cOnln = sysconf(_SC_NPROCESSORS_ONLN);
+    cCpusSC = RT_MAX(cCpusSC, cOnln);
+# endif
+    Assert(cCpusSC > 0);
+    if (cCpusSC > 0)
+        return cCpusSC;
+#endif
+
+    /*
+     * The BSD 4.4 way.
+     */
+#if defined(CTL_HW) && defined(HW_NCPU)
+    int aiMib[2];
+    aiMib[0] = CTL_HW;
+    aiMib[1] = HW_NCPU;
+    int cCpus = -1;
+    size_t cb = sizeof(cCpus);
+    int rc = sysctl(aiMib, RT_ELEMENTS(aiMib), &cCpus, &cb, NULL, 0);
+    if (rc != -1 && cCpus >= 1)
+        return cCpus;
+#endif
+    return 1;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTPathUserDocuments-posix.cpp b/src/VBox/Runtime/r3/posix/RTPathUserDocuments-posix.cpp
new file mode 100644
index 00000000..ee8c8036
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTPathUserDocuments-posix.cpp
@@ -0,0 +1,63 @@
+/* $Id: RTPathUserDocuments-posix.cpp $ */
+/** @file
+ * IPRT - RTPathUserDocuments, posix ring-3.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/path.h>
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+
+RTDECL(int) RTPathUserDocuments(char *pszPath, size_t cchPath)
+{
+    /*
+     * Validate input
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(cchPath, VERR_INVALID_PARAMETER);
+
+    int rc = RTPathUserHome(pszPath, cchPath);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rc = RTPathAppend(pszPath, cchPath, "Documents");
+    if (RT_FAILURE(rc))
+        *pszPath = '\0';
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTPathUserHome-posix.cpp b/src/VBox/Runtime/r3/posix/RTPathUserHome-posix.cpp
new file mode 100644
index 00000000..daa30ea1
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTPathUserHome-posix.cpp
@@ -0,0 +1,173 @@
+/* $Id: RTPathUserHome-posix.cpp $ */
+/** @file
+ * IPRT - Path Manipulation, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <pwd.h>
+
+#include <iprt/path.h>
+#include <iprt/env.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/path.h"
+#include "internal/fs.h"
+
+
+#ifndef RT_OS_L4
+/**
+ * Worker for RTPathUserHome that looks up the home directory
+ * using the getpwuid_r api.
+ *
+ * @returns IPRT status code.
+ * @param   pszPath     The path buffer.
+ * @param   cchPath     The size of the buffer.
+ * @param   uid         The User ID to query the home directory of.
+ */
+static int rtPathUserHomeByPasswd(char *pszPath, size_t cchPath, uid_t uid)
+{
+    /*
+     * The getpwuid_r function uses the passed in buffer to "allocate" any
+     * extra memory it needs. On some systems we should probably use the
+     * sysconf function to find the appropriate buffer size, but since it won't
+     * work everywhere we'll settle with a 5KB buffer and ASSUME that it'll
+     * suffice for even the lengthiest user descriptions...
+     */
+    char            achBuffer[5120];
+    struct passwd   Passwd;
+    struct passwd  *pPasswd;
+    memset(&Passwd, 0, sizeof(Passwd));
+    int rc = getpwuid_r(uid, &Passwd, &achBuffer[0], sizeof(achBuffer), &pPasswd);
+    if (rc != 0)
+        return RTErrConvertFromErrno(rc);
+    if (!pPasswd) /* uid not found in /etc/passwd */
+        return VERR_PATH_NOT_FOUND;
+
+    /*
+     * Check that it isn't empty and that it exists.
+     */
+    struct stat st;
+    if (    !pPasswd->pw_dir
+        ||  !*pPasswd->pw_dir
+        ||  stat(pPasswd->pw_dir, &st)
+        ||  !S_ISDIR(st.st_mode))
+        return VERR_PATH_NOT_FOUND;
+
+    /*
+     * Convert it to UTF-8 and copy it to the return buffer.
+     */
+    return rtPathFromNativeCopy(pszPath, cchPath, pPasswd->pw_dir, NULL);
+}
+#endif
+
+
+/**
+ * Worker for RTPathUserHome that looks up the home directory
+ * using the HOME environment variable.
+ *
+ * @returns IPRT status code.
+ * @param   pszPath     The path buffer.
+ * @param   cchPath     The size of the buffer.
+ */
+static int rtPathUserHomeByEnv(char *pszPath, size_t cchPath)
+{
+    /*
+     * Get HOME env. var it and validate it's existance.
+     */
+    int         rc      = VERR_PATH_NOT_FOUND;
+    const char *pszHome = RTEnvGet("HOME"); /** @todo Codeset confusion in RTEnv. */
+    if (pszHome)
+
+    {
+        struct stat st;
+        if (    !stat(pszHome, &st)
+            &&  S_ISDIR(st.st_mode))
+            rc = rtPathFromNativeCopy(pszPath, cchPath, pszHome, NULL);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPathUserHome(char *pszPath, size_t cchPath)
+{
+    int rc;
+#ifndef RT_OS_L4
+    /*
+     * We make an exception for the root user and use the system call
+     * getpwuid_r to determine their initial home path instead of
+     * reading it from the $HOME variable.  This is because the $HOME
+     * variable does not get changed by sudo (and possibly su and others)
+     * which can cause root-owned files to appear in user's home folders.
+     */
+     uid_t uid = geteuid();
+     if (!uid)
+         rc = rtPathUserHomeByPasswd(pszPath, cchPath, uid);
+     else
+         rc = rtPathUserHomeByEnv(pszPath, cchPath);
+
+     /*
+      * On failure, retry using the alternative method.
+      * (Should perhaps restrict the retry cases a bit more here...)
+      */
+     if (   RT_FAILURE(rc)
+         && rc != VERR_BUFFER_OVERFLOW)
+     {
+         if (!uid)
+             rc = rtPathUserHomeByEnv(pszPath, cchPath);
+         else
+             rc = rtPathUserHomeByPasswd(pszPath, cchPath, uid);
+     }
+#else  /* RT_OS_L4 */
+    rc = rtPathUserHomeByEnv(pszPath, cchPath);
+#endif /* RT_OS_L4 */
+
+    LogFlow(("RTPathUserHome(%p:{%s}, %u): returns %Rrc\n", pszPath,
+             RT_SUCCESS(rc) ? pszPath : "<failed>",  cchPath, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTSystemQueryOSInfo-posix.cpp b/src/VBox/Runtime/r3/posix/RTSystemQueryOSInfo-posix.cpp
new file mode 100644
index 00000000..6dc2f975
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTSystemQueryOSInfo-posix.cpp
@@ -0,0 +1,100 @@
+/* $Id: RTSystemQueryOSInfo-posix.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryOSInfo, POSIX implementation.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/errcore.h>
+
+#include <errno.h>
+#include <sys/utsname.h>
+
+
+RTDECL(int) RTSystemQueryOSInfo(RTSYSOSINFO enmInfo, char *pszInfo, size_t cchInfo)
+{
+    /*
+     * Quick validation.
+     */
+    AssertReturn(enmInfo > RTSYSOSINFO_INVALID && enmInfo < RTSYSOSINFO_END, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszInfo, VERR_INVALID_POINTER);
+    if (!cchInfo)
+        return VERR_BUFFER_OVERFLOW;
+
+    /*
+     * Handle the request.
+     */
+    switch (enmInfo)
+    {
+        case RTSYSOSINFO_PRODUCT:
+        case RTSYSOSINFO_RELEASE:
+        case RTSYSOSINFO_VERSION:
+        {
+            struct utsname UtsInfo;
+            if (uname(&UtsInfo) < 0)
+                return RTErrConvertFromErrno(errno);
+            const char *pszSrc;
+            switch (enmInfo)
+            {
+                case RTSYSOSINFO_PRODUCT:   pszSrc = UtsInfo.sysname; break;
+                case RTSYSOSINFO_RELEASE:   pszSrc = UtsInfo.release; break;
+                case RTSYSOSINFO_VERSION:   pszSrc = UtsInfo.version; break;
+                default: AssertFatalFailed(); /* screw gcc */
+            }
+            size_t cch = strlen(pszSrc);
+            if (cch < cchInfo)
+            {
+                memcpy(pszInfo, pszSrc, cch + 1);
+                return VINF_SUCCESS;
+            }
+            memcpy(pszInfo, pszSrc, cchInfo - 1);
+            pszInfo[cchInfo - 1] = '\0';
+            return VERR_BUFFER_OVERFLOW;
+        }
+
+
+        case RTSYSOSINFO_SERVICE_PACK:
+        default:
+            *pszInfo = '\0';
+            return VERR_NOT_SUPPORTED;
+    }
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTSystemQueryTotalRam-posix.cpp b/src/VBox/Runtime/r3/posix/RTSystemQueryTotalRam-posix.cpp
new file mode 100644
index 00000000..151a12f5
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTSystemQueryTotalRam-posix.cpp
@@ -0,0 +1,61 @@
+/* $Id: RTSystemQueryTotalRam-posix.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, windows ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+    return VERR_NOT_IMPLEMENTED;
+}
diff --git a/src/VBox/Runtime/r3/posix/RTTimeNow-posix.cpp b/src/VBox/Runtime/r3/posix/RTTimeNow-posix.cpp
new file mode 100644
index 00000000..b00394c8
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTTimeNow-posix.cpp
@@ -0,0 +1,61 @@
+/* $Id: RTTimeNow-posix.cpp $ */
+/** @file
+ * IPRT - RTTimeNow, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <sys/time.h>
+#include <time.h>
+
+#include <iprt/time.h>
+
+
+/**
+ * Gets the current system time.
+ *
+ * @returns pTime.
+ * @param   pTime   Where to store the time.
+ */
+RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
+{
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return RTTimeSpecSetTimeval(pTime, &tv);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTTimeSet-posix.cpp b/src/VBox/Runtime/r3/posix/RTTimeSet-posix.cpp
new file mode 100644
index 00000000..8d848b50
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTTimeSet-posix.cpp
@@ -0,0 +1,60 @@
+/* $Id: RTTimeSet-posix.cpp $ */
+/** @file
+ * IPRT - RTTimeSet, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <sys/time.h>
+#include <time.h>
+#include <errno.h>
+
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+
+
+RTDECL(int) RTTimeSet(PCRTTIMESPEC pTime)
+{
+    struct timeval tv;
+    if (settimeofday(RTTimeSpecGetTimeval(pTime, &tv), NULL) == 0)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/RTTimeZoneGetCurrent-posix.cpp b/src/VBox/Runtime/r3/posix/RTTimeZoneGetCurrent-posix.cpp
new file mode 100644
index 00000000..6d0d84d0
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/RTTimeZoneGetCurrent-posix.cpp
@@ -0,0 +1,262 @@
+/* $Id: RTTimeZoneGetCurrent-posix.cpp $ */
+/** @file
+ * IPRT - RTTimeZoneGetCurrent, POSIX.
+ */
+
+/*
+ * Copyright (C) 2020-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/env.h>
+#include <iprt/file.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/errcore.h>
+#include <iprt/types.h>
+#include <iprt/symlink.h>
+#include <iprt/stream.h>
+
+#if defined(RT_OS_DARWIN) || defined(RT_OS_SOLARIS)
+# include <tzfile.h>
+#else
+# define TZDIR                   "/usr/share/zoneinfo"
+# define TZ_MAGIC                "TZif"
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#define PATH_LOCALTIME           "/etc/localtime"
+#if defined(RT_OS_FREEBSD)
+# define PATH_TIMEZONE           "/var/db/zoneinfo"
+#else
+# define PATH_TIMEZONE           "/etc/timezone"
+#endif
+#define PATH_SYSCONFIG_CLOCK     "/etc/sysconfig/clock"
+
+
+/**
+ * Checks if a time zone database file is valid by verifying it begins with
+ * TZ_MAGIC.
+ *
+ * @returns IPRT status code.
+ * @param   pszTimezone         The time zone database file relative to
+ *                              <tzfile.h>:TZDIR (normally /usr/share/zoneinfo),
+ *                              e.g. Europe/London, or Etc/UTC, or UTC, or etc.
+ *
+ * @note    File format is documented in RFC-8536.
+ */
+static int rtIsValidTimeZoneFile(const char *pszTimeZone)
+{
+    if (pszTimeZone == NULL || *pszTimeZone == '\0' || *pszTimeZone == '/')
+        return VERR_INVALID_PARAMETER;
+
+    int rc = RTStrValidateEncoding(pszTimeZone);
+    if (RT_SUCCESS(rc))
+    {
+        /* construct full pathname of the time zone file */
+        char szTZPath[RTPATH_MAX];
+        rc = RTPathJoin(szTZPath, sizeof(szTZPath), TZDIR, pszTimeZone);
+        if (RT_SUCCESS(rc))
+        {
+            /* open the time zone file and check that it begins with the correct magic number */
+            RTFILE hFile = NIL_RTFILE;
+            rc = RTFileOpen(&hFile, szTZPath, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE);
+            if (RT_SUCCESS(rc))
+            {
+                char achTZBuf[sizeof(TZ_MAGIC)];
+                rc = RTFileRead(hFile, achTZBuf, sizeof(achTZBuf), NULL);
+                RTFileClose(hFile);
+                if (RT_SUCCESS(rc))
+                {
+                    if (memcmp(achTZBuf, RT_STR_TUPLE(TZ_MAGIC)) == 0)
+                        rc = VINF_SUCCESS;
+                    else
+                        rc = VERR_INVALID_MAGIC;
+                }
+            }
+        }
+    }
+
+    return rc;
+}
+
+
+/**
+ * Return the system time zone.
+ *
+ * @returns IPRT status code.
+ * @param   pszName         The buffer to return the time zone in.
+ * @param   cbName          The size of the pszName buffer.
+ */
+RTDECL(int) RTTimeZoneGetCurrent(char *pszName, size_t cbName)
+{
+    int rc = RTEnvGetEx(RTENV_DEFAULT, "TZ", pszName, cbName, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * $TZ can have two different formats and one of them doesn't specify
+         * a time zone database file under <tzfile.h>:TZDIR but since all
+         * current callers of this routine expect a time zone filename we do
+         * the validation check here so that if it is invalid then we fall back
+         * to the other mechanisms to return the system's current time zone.
+         */
+        if (*pszName == ':') /* POSIX allows $TZ to begin with a colon (:) so we allow for that here */
+            memmove(pszName, pszName + 1, strlen(pszName));
+        /** @todo this isn't perfect for absolute paths... Should probably try treat
+         *        it like /etc/localtime. */
+        rc = rtIsValidTimeZoneFile(pszName);
+        if (RT_SUCCESS(rc))
+            return rc;
+    }
+    else if (rc != VERR_ENV_VAR_NOT_FOUND)
+        return rc;
+
+    /*
+     * /etc/localtime is a symbolic link to the system time zone on many OSes
+     * including Solaris, macOS, Ubuntu, RH/OEL 6 and later, Arch Linux, NetBSD,
+     * and etc.  We extract the time zone pathname relative to TZDIR defined in
+     * <tzfile.h> which is normally /usr/share/zoneinfo.
+     *
+     * N.B. Some OSes have /etc/localtime as a regular file instead of a
+     * symlink and while we could trawl through all the files under TZDIR
+     * looking for a match we instead fallback to other popular mechanisms of
+     * specifying the system-wide time zone for the sake of simplicity.
+     */
+    char szBuf[RTPATH_MAX];
+    const char *pszPath = PATH_LOCALTIME;
+    if (RTSymlinkExists(pszPath))
+    {
+        /* the contents of the symink may contain '..' or other links */
+        char szLinkPathReal[RTPATH_MAX];
+        rc = RTPathReal(pszPath, szLinkPathReal, sizeof(szLinkPathReal));
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTPathReal(TZDIR, szBuf, sizeof(szBuf));
+            AssertRC(rc);
+            if (RT_SUCCESS(rc))
+            {
+                Assert(RTPathStartsWith(szLinkPathReal, szBuf));
+                if (RTPathStartsWith(szLinkPathReal, szBuf))
+                {
+                    /* <tzfile.h>:TZDIR doesn't include a trailing slash */
+                    const char *pszTimeZone = &szLinkPathReal[strlen(szBuf) + 1];
+                    rc = rtIsValidTimeZoneFile(pszTimeZone);
+                    if (RT_SUCCESS(rc))
+                        return RTStrCopy(pszName, cbName, pszTimeZone);
+                }
+            }
+        }
+    }
+
+    /*
+     * /etc/timezone is a regular file consisting of a single line containing
+     * the time zone (e.g. Europe/London or Etc/UTC or etc.) and is used by a
+     * variety of Linux distros such as Ubuntu, Gentoo, Debian, and etc.
+     * The equivalent on FreeBSD is /var/db/zoneinfo.
+     */
+    pszPath = PATH_TIMEZONE;
+    if (RTFileExists(pszPath))
+    {
+        RTFILE hFile = NIL_RTFILE;
+        rc = RTFileOpen(&hFile, PATH_TIMEZONE, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE);
+        if (RT_SUCCESS(rc))
+        {
+            size_t cbRead = 0;
+            rc = RTFileRead(hFile, szBuf, sizeof(szBuf), &cbRead);
+            RTFileClose(hFile);
+            if (RT_SUCCESS(rc) && cbRead > 0)
+            {
+                /* Get the first line and strip it. */
+                szBuf[RT_MIN(sizeof(szBuf) - 1, cbRead)] = '\0';
+                size_t const offNewLine = RTStrOffCharOrTerm(szBuf, '\n');
+                szBuf[offNewLine] = '\0';
+                const char *pszTimeZone = RTStrStrip(szBuf);
+
+                rc = rtIsValidTimeZoneFile(pszTimeZone);
+                if (RT_SUCCESS(rc))
+                    return RTStrCopy(pszName, cbName, pszTimeZone);
+            }
+        }
+    }
+
+    /*
+     * Older versions of RedHat / OEL don't have /etc/localtime as a symlink or
+     * /etc/timezone but instead have /etc/sysconfig/clock which contains a line
+     * of the syntax ZONE=Europe/London or ZONE="Europe/London" amongst other entries.
+     */
+    pszPath = PATH_SYSCONFIG_CLOCK;
+    if (RTFileExists(pszPath))
+    {
+        PRTSTREAM pStrm;
+        rc = RTStrmOpen(pszPath, "r", &pStrm);
+        if (RT_SUCCESS(rc))
+        {
+            while (RT_SUCCESS(rc = RTStrmGetLine(pStrm, szBuf, sizeof(szBuf))))
+            {
+                static char const s_szVarEq[] = "ZONE=";
+                char             *pszStart    = RTStrStrip(szBuf);
+                if (memcmp(pszStart, RT_STR_TUPLE(s_szVarEq)) == 0)
+                {
+                    char *pszTimeZone = &pszStart[sizeof(s_szVarEq) - 1];
+
+                    /* Drop any quoting before using the value, assuming it is plain stuff: */
+                    if (*pszTimeZone == '\"' || *pszTimeZone == '\'')
+                    {
+                        pszTimeZone++;
+                        size_t const cchTimeZone = strlen(pszTimeZone);
+                        if (cchTimeZone && (pszTimeZone[cchTimeZone - 1] == '"' || pszTimeZone[cchTimeZone - 1] == '\''))
+                            pszTimeZone[cchTimeZone - 1] = '\0';
+                    }
+
+                    rc = rtIsValidTimeZoneFile(pszTimeZone);
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTStrmClose(pStrm);
+                        return RTStrCopy(pszName, cbName, pszTimeZone);
+                    }
+                }
+            }
+            RTStrmClose(pStrm);
+        }
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/allocex-r3-posix.cpp b/src/VBox/Runtime/r3/posix/allocex-r3-posix.cpp
new file mode 100644
index 00000000..b8f1a1ad
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/allocex-r3-posix.cpp
@@ -0,0 +1,120 @@
+/* $Id: allocex-r3-posix.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, Extended Alloc Workers, posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RTMEM_NO_WRAP_TO_EF_APIS
+#include <iprt/mem.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include "../allocex.h"
+
+#include <sys/mman.h>
+
+
+DECLHIDDEN(int) rtMemAllocEx16BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    AssertReturn(cbAlloc < _64K, VERR_NO_MEMORY);
+
+    /*
+     * Try with every possible address hint since the possible range is very limited.
+     */
+    int       fProt     = PROT_READ | PROT_WRITE | (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PROT_EXEC : 0);
+    uintptr_t uAddr     = 0x1000;
+    uintptr_t uAddrLast = _64K - uAddr - cbAlloc;
+    while (uAddr <= uAddrLast)
+    {
+        void *pv = mmap((void *)uAddr, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+        if (pv && (uintptr_t)pv <= uAddrLast)
+        {
+            *ppv = pv;
+            return VINF_SUCCESS;
+        }
+
+        if (pv)
+        {
+            munmap(pv, cbAlloc);
+            pv = NULL;
+        }
+        uAddr += _4K;
+    }
+
+    return VERR_NO_MEMORY;
+}
+
+
+DECLHIDDEN(int) rtMemAllocEx32BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    int     fProt = PROT_READ | PROT_WRITE | (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PROT_EXEC : 0);
+#if ARCH_BITS == 32
+    void   *pv = mmap(NULL, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+    if (pv)
+    {
+        *ppv = pv;
+        return VINF_SUCCESS;
+    }
+    return VERR_NO_MEMORY;
+
+#elif defined(RT_OS_LINUX)
+# ifdef MAP_32BIT
+    void *pv = mmap(NULL, cbAlloc, fProt, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
+    if (pv)
+    {
+        *ppv = pv;
+        return VINF_SUCCESS;
+    }
+# endif
+
+    /** @todo On linux, we need an accurate hint. Since I don't need this branch of
+     *        the code right now, I won't bother starting to parse
+     *        /proc/curproc/mmap right now... */
+#else
+#endif
+    return VERR_NOT_SUPPORTED;
+}
+
+
+DECLHIDDEN(void) rtMemFreeExYyBitReach(void *pv, size_t cb, uint32_t fFlags)
+{
+    RT_NOREF_PV(fFlags);
+    munmap(pv, cb);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/dir-posix.cpp b/src/VBox/Runtime/r3/posix/dir-posix.cpp
new file mode 100644
index 00000000..558085ab
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/dir-posix.cpp
@@ -0,0 +1,733 @@
+/* $Id: dir-posix.cpp $ */
+/** @file
+ * IPRT - Directory manipulation, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <dlfcn.h>
+#include <stdio.h>
+
+#include <iprt/dir.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include "internal/dir.h"
+#include "internal/fs.h"
+#include "internal/path.h"
+
+#if !defined(RT_OS_SOLARIS) && !defined(RT_OS_HAIKU)
+# define HAVE_DIRENT_D_TYPE 1
+#endif
+
+
+RTDECL(bool) RTDirExists(const char *pszPath)
+{
+    bool fRc = false;
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat s;
+        fRc = !stat(pszNativePath, &s)
+            && S_ISDIR(s.st_mode);
+
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTDirExists(%p={%s}): returns %RTbool\n", pszPath, pszPath, fRc));
+    return fRc;
+}
+
+
+RTDECL(int) RTDirCreate(const char *pszPath, RTFMODE fMode, uint32_t fCreate)
+{
+    RT_NOREF_PV(fCreate);
+
+    int rc;
+    fMode = rtFsModeNormalize(fMode, pszPath, 0, RTFS_TYPE_DIRECTORY);
+    if (rtFsModeIsValidPermissions(fMode))
+    {
+        char const *pszNativePath;
+        rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            struct stat st;
+            if (mkdir(pszNativePath, fMode & RTFS_UNIX_MASK) == 0)
+            {
+                /* If requested, we try make use the permission bits are set
+                   correctly when asked.  For now, we'll just ignore errors here. */
+                if (fCreate & RTDIRCREATE_FLAGS_IGNORE_UMASK)
+                {
+                    if (   stat(pszNativePath, &st)
+                        || (st.st_mode & 07777) != (fMode & 07777) )
+                        chmod(pszNativePath, fMode & RTFS_UNIX_MASK);
+                }
+                rc = VINF_SUCCESS;
+            }
+            else
+            {
+                rc = errno;
+                /*
+                 * Solaris mkdir returns ENOSYS on autofs directories, and also
+                 * did this apparently for NFS mount points in some Nevada
+                 * development builds. It also returned EACCES when it should
+                 * have returned EEXIST, which actually is within the POSIX
+                 * spec (not that I like this interpretation, but it seems
+                 * valid). Check ourselves.
+                 */
+                if (    rc == ENOSYS
+                    ||  rc == EACCES)
+                {
+                    rc = RTErrConvertFromErrno(rc);
+                    if (!stat(pszNativePath, &st))
+                        rc = VERR_ALREADY_EXISTS;
+                }
+                else
+                    rc = RTErrConvertFromErrno(rc);
+            }
+        }
+
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+    else
+    {
+        AssertMsgFailed(("Invalid file mode! %RTfmode\n", fMode));
+        rc = VERR_INVALID_FMODE;
+    }
+    LogFlow(("RTDirCreate(%p={%s}, %RTfmode): returns %Rrc\n", pszPath, pszPath, fMode, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTDirRemove(const char *pszPath)
+{
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (rmdir(pszNativePath))
+        {
+            rc = errno;
+            if (rc == EEXIST) /* Solaris returns this, the rest have ENOTEMPTY. */
+                rc = VERR_DIR_NOT_EMPTY;
+            else if (rc != ENOTDIR)
+                rc = RTErrConvertFromErrno(rc);
+            else
+            {
+                /*
+                 * This may be a valid path-not-found or it may be a non-directory in
+                 * the final component.  FsPerf want us to distinguish between the two,
+                 * and trailing slash shouldn't matter because it doesn't on windows...
+                 */
+                char       *pszFree = NULL;
+                const char *pszStat = pszNativePath;
+                size_t      cch     = strlen(pszNativePath);
+                if (cch > 2 && RTPATH_IS_SLASH(pszNativePath[cch - 1]))
+                {
+                    pszFree = (char *)RTMemTmpAlloc(cch);
+                    if (pszFree)
+                    {
+                        memcpy(pszFree, pszNativePath, cch);
+                        do
+                            pszFree[--cch] = '\0';
+                        while (cch > 2 && RTPATH_IS_SLASH(pszFree[cch - 1]));
+                        pszStat = pszFree;
+                    }
+                }
+
+                struct stat st;
+                if (!stat(pszStat, &st) && !S_ISDIR(st.st_mode))
+                    rc = VERR_NOT_A_DIRECTORY;
+                else
+                    rc = VERR_PATH_NOT_FOUND;
+
+                if (pszFree)
+                    RTMemTmpFree(pszFree);
+            }
+        }
+
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTDirRemove(%p={%s}): returns %Rrc\n", pszPath, pszPath, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTDirFlush(const char *pszPath)
+{
+    /*
+     * Linux: The fsync() man page hints at this being required for ensuring
+     * consistency between directory and file in case of a crash.
+     *
+     * Solaris: No mentioned is made of directories on the fsync man page.
+     * While rename+fsync will do what we want on ZFS, the code needs more
+     * careful studying wrt whether the directory entry of a new file is
+     * implicitly synced when the file is synced (it's very likely for ZFS).
+     *
+     * FreeBSD: The FFS fsync code seems to flush the directory entry as well
+     * in some cases.  Don't know exactly what's up with rename, but from the
+     * look of things fsync(dir) should work.
+     */
+    int rc;
+#ifdef O_DIRECTORY
+    int fd = open(pszPath, O_RDONLY | O_DIRECTORY, 0);
+#else
+    int fd = open(pszPath, O_RDONLY, 0);
+#endif
+    if (fd >= 0)
+    {
+        if (fsync(fd) == 0)
+            rc = VINF_SUCCESS;
+        else
+        {
+            /* Linux fsync(2) man page documents both errors as an indication
+             * that the file descriptor can't be flushed (seen EINVAL for usual
+             * directories on CIFS). BSD (OS X) fsync(2) documents only the
+             * latter, and Solaris fsync(3C) pretends there is no problem. */
+            if (errno == EROFS || errno == EINVAL)
+                rc = VERR_NOT_SUPPORTED;
+            else
+                rc = RTErrConvertFromErrno(errno);
+        }
+        close(fd);
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+    return rc;
+}
+
+
+size_t rtDirNativeGetStructSize(const char *pszPath)
+{
+    long cbNameMax = pathconf(pszPath, _PC_NAME_MAX);
+# ifdef NAME_MAX
+    if (cbNameMax < NAME_MAX)           /* This is plain paranoia, but it doesn't hurt. */
+        cbNameMax = NAME_MAX;
+# endif
+# ifdef _XOPEN_NAME_MAX
+    if (cbNameMax < _XOPEN_NAME_MAX)    /* Ditto. */
+        cbNameMax = _XOPEN_NAME_MAX;
+# endif
+    size_t cbDir = RT_UOFFSETOF_DYN(RTDIRINTERNAL, Data.d_name[cbNameMax + 1]);
+    if (cbDir < sizeof(RTDIRINTERNAL))  /* Ditto. */
+        cbDir = sizeof(RTDIRINTERNAL);
+    cbDir = RT_ALIGN_Z(cbDir, 8);
+
+    return cbDir;
+}
+
+
+int rtDirNativeOpen(PRTDIRINTERNAL pDir, uintptr_t hRelativeDir, void *pvNativeRelative)
+{
+    NOREF(hRelativeDir);
+    NOREF(pvNativeRelative);
+
+    /*
+     * Convert to a native path and try opendir.
+     */
+    char       *pszSlash = NULL;
+    char const *pszNativePath;
+    int         rc;
+    if (   !(pDir->fFlags & RTDIR_F_NO_FOLLOW)
+        || pDir->fDirSlash
+        || pDir->cchPath <= 1)
+        rc = rtPathToNative(&pszNativePath, pDir->pszPath, NULL);
+    else
+    {
+        pszSlash = (char *)&pDir->pszPath[pDir->cchPath - 1];
+        *pszSlash = '\0';
+        rc = rtPathToNative(&pszNativePath, pDir->pszPath, NULL);
+    }
+    if (RT_SUCCESS(rc))
+    {
+        if (   !(pDir->fFlags & RTDIR_F_NO_FOLLOW)
+            || pDir->fDirSlash)
+            pDir->pDir = opendir(pszNativePath);
+        else
+        {
+            /*
+             * If we can get fdopendir() and have both O_NOFOLLOW and O_DIRECTORY,
+             * we will use open() to safely open the directory without following
+             * symlinks in the final component, and then use fdopendir to get a DIR
+             * from the file descriptor.
+             *
+             * If we cannot get that, we will use lstat() + opendir() as a fallback.
+             *
+             * We ASSUME that support for the O_NOFOLLOW and O_DIRECTORY flags is
+             * older than fdopendir().
+             */
+#if defined(O_NOFOLLOW) && defined(O_DIRECTORY)
+            /* Need to resolve fdopendir dynamically. */
+            typedef DIR * (*PFNFDOPENDIR)(int);
+            static PFNFDOPENDIR  s_pfnFdOpenDir = NULL;
+            static bool volatile s_fInitalized = false;
+
+            PFNFDOPENDIR pfnFdOpenDir = s_pfnFdOpenDir;
+            ASMCompilerBarrier();
+            if (s_fInitalized)
+            { /* likely */ }
+            else
+            {
+                pfnFdOpenDir = (PFNFDOPENDIR)(uintptr_t)dlsym(RTLD_DEFAULT, "fdopendir");
+                s_pfnFdOpenDir = pfnFdOpenDir;
+                ASMAtomicWriteBool(&s_fInitalized, true);
+            }
+
+            if (pfnFdOpenDir)
+            {
+                int fd = open(pszNativePath, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0);
+                if (fd >= 0)
+                {
+                    pDir->pDir = pfnFdOpenDir(fd);
+                    if (RT_UNLIKELY(!pDir->pDir))
+                    {
+                        rc = RTErrConvertFromErrno(errno);
+                        close(fd);
+                    }
+                }
+                else
+                {
+                    /* WSL returns ELOOP here, but we take no chances that O_NOFOLLOW
+                       takes precedence over O_DIRECTORY everywhere. */
+                    int iErr = errno;
+                    if (iErr == ELOOP || iErr == ENOTDIR)
+                    {
+                        struct stat St;
+                        if (   lstat(pszNativePath, &St) == 0
+                            && S_ISLNK(St.st_mode))
+                            rc = VERR_IS_A_SYMLINK;
+                        else
+                            rc = RTErrConvertFromErrno(iErr);
+                    }
+                }
+            }
+            else
+#endif
+            {
+                /* Fallback.  This contains a race condition. */
+                struct stat St;
+                if (   lstat(pszNativePath, &St) != 0
+                    || !S_ISLNK(St.st_mode))
+                    pDir->pDir = opendir(pszNativePath);
+                else
+                    rc = VERR_IS_A_SYMLINK;
+            }
+        }
+        if (pDir->pDir)
+        {
+            /*
+             * Init data (allocated as all zeros).
+             */
+            pDir->fDataUnread = false; /* spelling it out */
+        }
+        else if (RT_SUCCESS_NP(rc))
+            rc = RTErrConvertFromErrno(errno);
+
+        rtPathFreeNative(pszNativePath, pDir->pszPath);
+    }
+    if (pszSlash)
+        *pszSlash = RTPATH_SLASH;
+    return rc;
+}
+
+
+RTDECL(int) RTDirClose(RTDIR hDir)
+{
+    PRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate input.
+     */
+    if (!pDir)
+        return VERR_INVALID_PARAMETER;
+    if (pDir->u32Magic != RTDIR_MAGIC)
+    {
+        AssertMsgFailed(("Invalid pDir=%p\n", pDir));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Close the handle.
+     */
+    int rc = VINF_SUCCESS;
+    pDir->u32Magic = RTDIR_MAGIC_DEAD;
+    if (closedir(pDir->pDir))
+    {
+        rc = RTErrConvertFromErrno(errno);
+        AssertMsgFailed(("closedir(%p) -> errno=%d (%Rrc)\n", pDir->pDir, errno, rc));
+    }
+
+    RTMemFree(pDir);
+    return rc;
+}
+
+
+/**
+ * Ensure that there is unread data in the buffer
+ * and that there is a converted filename hanging around.
+ *
+ * @returns IPRT status code.
+ * @param   pDir        the open directory. Fully validated.
+ */
+static int rtDirReadMore(PRTDIRINTERNAL pDir)
+{
+    /** @todo try avoid the rematching on buffer overflow errors. */
+    for (;;)
+    {
+        /*
+         * Fetch data?
+         */
+        if (!pDir->fDataUnread)
+        {
+            struct dirent *pResult = NULL;
+#if RT_GNUC_PREREQ(4, 6)
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+            int rc = readdir_r(pDir->pDir, &pDir->Data, &pResult);
+#if RT_GNUC_PREREQ(4, 6)
+# pragma GCC diagnostic pop
+#endif
+            if (rc)
+            {
+                rc = RTErrConvertFromErrno(rc);
+                /** @todo Consider translating ENOENT (The current
+                 *        position of the directory stream is invalid)
+                 *        differently. */
+                AssertMsg(rc == VERR_FILE_NOT_FOUND, ("%Rrc\n", rc));
+                return rc;
+            }
+            if (!pResult)
+                return VERR_NO_MORE_FILES;
+        }
+
+        /*
+         * Convert the filename to UTF-8.
+         */
+        if (!pDir->pszName)
+        {
+            int rc = rtPathFromNative(&pDir->pszName, pDir->Data.d_name, pDir->pszPath);
+            if (RT_FAILURE(rc))
+            {
+                pDir->pszName = NULL;
+                return rc;
+            }
+            pDir->cchName = strlen(pDir->pszName);
+        }
+        if (    !pDir->pfnFilter
+            ||  pDir->pfnFilter(pDir, pDir->pszName))
+            break;
+        rtPathFreeIprt(pDir->pszName, pDir->Data.d_name);
+        pDir->pszName     = NULL;
+        pDir->fDataUnread = false;
+    }
+
+    pDir->fDataUnread = true;
+    return VINF_SUCCESS;
+}
+
+
+#ifdef HAVE_DIRENT_D_TYPE
+/**
+ * Converts the d_type field to IPRT directory entry type.
+ *
+ * @returns IPRT directory entry type.
+ * @param    Unix
+ */
+static RTDIRENTRYTYPE rtDirType(int iType)
+{
+    switch (iType)
+    {
+        case DT_UNKNOWN:    return RTDIRENTRYTYPE_UNKNOWN;
+        case DT_FIFO:       return RTDIRENTRYTYPE_FIFO;
+        case DT_CHR:        return RTDIRENTRYTYPE_DEV_CHAR;
+        case DT_DIR:        return RTDIRENTRYTYPE_DIRECTORY;
+        case DT_BLK:        return RTDIRENTRYTYPE_DEV_BLOCK;
+        case DT_REG:        return RTDIRENTRYTYPE_FILE;
+        case DT_LNK:        return RTDIRENTRYTYPE_SYMLINK;
+        case DT_SOCK:       return RTDIRENTRYTYPE_SOCKET;
+        case DT_WHT:        return RTDIRENTRYTYPE_WHITEOUT;
+        default:
+            AssertMsgFailed(("iType=%d\n", iType));
+            return RTDIRENTRYTYPE_UNKNOWN;
+    }
+}
+#endif /*HAVE_DIRENT_D_TYPE */
+
+
+RTDECL(int) RTDirRead(RTDIR hDir, PRTDIRENTRY pDirEntry, size_t *pcbDirEntry)
+{
+    PRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate and digest input.
+     */
+    if (!rtDirValidHandle(pDir))
+        return VERR_INVALID_PARAMETER;
+    AssertPtrReturn(pDirEntry, VERR_INVALID_POINTER);
+
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        AssertPtrReturn(pcbDirEntry, VERR_INVALID_POINTER);
+        cbDirEntry = *pcbDirEntry;
+        AssertMsgReturn(cbDirEntry >= RT_UOFFSETOF(RTDIRENTRY, szName[2]),
+                        ("Invalid *pcbDirEntry=%d (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRYEX, szName[2])),
+                        VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Fetch more data if necessary and/or convert the name.
+     */
+    int rc = rtDirReadMore(pDir);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Check if we've got enough space to return the data.
+         */
+        const char  *pszName    = pDir->pszName;
+        const size_t cchName    = pDir->cchName;
+        const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRY, szName[1]) + cchName;
+        if (pcbDirEntry)
+            *pcbDirEntry = cbRequired;
+        if (cbRequired <= cbDirEntry)
+        {
+            /*
+             * Setup the returned data.
+             */
+            pDirEntry->INodeId = pDir->Data.d_ino; /* may need #ifdefing later */
+#ifdef HAVE_DIRENT_D_TYPE
+            pDirEntry->enmType = rtDirType(pDir->Data.d_type);
+#else
+            pDirEntry->enmType = RTDIRENTRYTYPE_UNKNOWN;
+#endif
+            pDirEntry->cbName  = (uint16_t)cchName;
+            Assert(pDirEntry->cbName == cchName);
+            memcpy(pDirEntry->szName, pszName, cchName + 1);
+
+            /* free cached data */
+            pDir->fDataUnread  = false;
+            rtPathFreeIprt(pDir->pszName, pDir->Data.d_name);
+            pDir->pszName = NULL;
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+
+    LogFlow(("RTDirRead(%p:{%s}, %p:{%s}, %p:{%u}): returns %Rrc\n",
+             pDir, pDir->pszPath, pDirEntry, RT_SUCCESS(rc) ? pDirEntry->szName : "<failed>",
+             pcbDirEntry, pcbDirEntry ? *pcbDirEntry : 0, rc));
+    return rc;
+}
+
+
+/**
+ * Fills dummy info into the info structure.
+ * This function is called if we cannot stat the file.
+ *
+ * @param   pInfo   The struct in question.
+ * @param
+ */
+static void rtDirSetDummyInfo(PRTFSOBJINFO pInfo, RTDIRENTRYTYPE enmType)
+{
+    pInfo->cbObject = 0;
+    pInfo->cbAllocated = 0;
+    RTTimeSpecSetNano(&pInfo->AccessTime, 0);
+    RTTimeSpecSetNano(&pInfo->ModificationTime, 0);
+    RTTimeSpecSetNano(&pInfo->ChangeTime, 0);
+    RTTimeSpecSetNano(&pInfo->BirthTime, 0);
+    memset(&pInfo->Attr, 0, sizeof(pInfo->Attr));
+    pInfo->Attr.enmAdditional = RTFSOBJATTRADD_NOTHING;
+    switch (enmType)
+    {
+        default:
+        case RTDIRENTRYTYPE_UNKNOWN:    pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL;                       break;
+        case RTDIRENTRYTYPE_FIFO:       pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_FIFO;      break;
+        case RTDIRENTRYTYPE_DEV_CHAR:   pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_DEV_CHAR;  break;
+        case RTDIRENTRYTYPE_DIRECTORY:  pInfo->Attr.fMode = RTFS_DOS_DIRECTORY | RTFS_TYPE_DIRECTORY; break;
+        case RTDIRENTRYTYPE_DEV_BLOCK:  pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_DEV_BLOCK; break;
+        case RTDIRENTRYTYPE_FILE:       pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_FILE;      break;
+        case RTDIRENTRYTYPE_SYMLINK:    pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_SYMLINK;   break;
+        case RTDIRENTRYTYPE_SOCKET:     pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_SOCKET;    break;
+        case RTDIRENTRYTYPE_WHITEOUT:   pInfo->Attr.fMode = RTFS_DOS_NT_NORMAL | RTFS_TYPE_WHITEOUT;  break;
+    }
+}
+
+
+RTDECL(int) RTDirReadEx(RTDIR hDir, PRTDIRENTRYEX pDirEntry, size_t *pcbDirEntry,
+                        RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    PRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate and digest input.
+     */
+    if (!rtDirValidHandle(pDir))
+        return VERR_INVALID_PARAMETER;
+    AssertPtrReturn(pDirEntry, VERR_INVALID_POINTER);
+    AssertMsgReturn(    enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING
+                    &&  enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                    ("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs),
+                    VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        AssertPtrReturn(pcbDirEntry, VERR_INVALID_POINTER);
+        cbDirEntry = *pcbDirEntry;
+        AssertMsgReturn(cbDirEntry >= RT_UOFFSETOF(RTDIRENTRYEX, szName[2]),
+                        ("Invalid *pcbDirEntry=%zu (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRYEX, szName[2])),
+                        VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Fetch more data if necessary and/or convert the name.
+     */
+    int rc = rtDirReadMore(pDir);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Check if we've got enough space to return the data.
+         */
+        const char  *pszName    = pDir->pszName;
+        const size_t cchName    = pDir->cchName;
+        const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRYEX, szName[1]) + cchName;
+        if (pcbDirEntry)
+            *pcbDirEntry = cbRequired;
+        if (cbRequired <= cbDirEntry)
+        {
+            /*
+             * Setup the returned data.
+             */
+            pDirEntry->cwcShortName = 0;
+            pDirEntry->wszShortName[0] = 0;
+            pDirEntry->cbName  = (uint16_t)cchName;
+            Assert(pDirEntry->cbName == cchName);
+            memcpy(pDirEntry->szName, pszName, cchName + 1);
+
+            /* get the info data */
+            size_t cch = cchName + pDir->cchPath + 1;
+            char *pszNamePath = (char *)alloca(cch);
+            if (pszNamePath)
+            {
+                memcpy(pszNamePath, pDir->pszPath, pDir->cchPath);
+                memcpy(pszNamePath + pDir->cchPath, pszName, cchName + 1);
+                rc = RTPathQueryInfoEx(pszNamePath, &pDirEntry->Info, enmAdditionalAttribs, fFlags);
+            }
+            else
+                rc = VERR_NO_MEMORY;
+            if (RT_FAILURE(rc))
+            {
+#ifdef HAVE_DIRENT_D_TYPE
+                rtDirSetDummyInfo(&pDirEntry->Info, rtDirType(pDir->Data.d_type));
+#else
+                rtDirSetDummyInfo(&pDirEntry->Info, RTDIRENTRYTYPE_UNKNOWN);
+#endif
+                rc = VWRN_NO_DIRENT_INFO;
+            }
+
+            /* free cached data */
+            pDir->fDataUnread  = false;
+            rtPathFreeIprt(pDir->pszName, pDir->Data.d_name);
+            pDir->pszName = NULL;
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTDirRewind(RTDIR hDir)
+{
+    PRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate and digest input.
+     */
+    if (!rtDirValidHandle(pDir))
+        return VERR_INVALID_PARAMETER;
+
+    /*
+     * Do the rewinding.
+     */
+    /** @todo OS/2 does not rescan the directory as it should. */
+    rewinddir(pDir->pDir);
+    pDir->fDataUnread = false;
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTDirRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(*pszSrc, ("%p\n", pszSrc), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(*pszDst, ("%p\n", pszDst), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Take common cause with RTPathRename.
+     */
+    int rc = rtPathPosixRename(pszSrc, pszDst, fRename, RTFS_TYPE_DIRECTORY);
+
+    LogFlow(("RTDirRename(%p:{%s}, %p:{%s}): returns %Rrc\n",
+             pszSrc, pszSrc, pszDst, pszDst, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/env-posix.cpp b/src/VBox/Runtime/r3/posix/env-posix.cpp
new file mode 100644
index 00000000..60a9112e
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/env-posix.cpp
@@ -0,0 +1,179 @@
+/* $Id: env-posix.cpp $ */
+/** @file
+ * IPRT - Environment, Posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RT_OS_DARWIN
+/* pick the correct prototype for unsetenv. */
+# define _POSIX_C_SOURCE 1
+#endif
+#include <iprt/env.h>
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#if defined(DEBUG) && defined(RT_OS_LINUX)
+# include <iprt/asm.h>
+#endif
+#include <iprt/err.h>
+#include <iprt/string.h>
+
+#include <stdlib.h>
+#include <errno.h>
+
+#include "internal/alignmentchecks.h"
+
+
+RTDECL(bool) RTEnvExistsBad(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, false);
+    return RTEnvGetBad(pszVar) != NULL;
+}
+
+
+RTDECL(bool) RTEnvExist(const char *pszVar)
+{
+    return RTEnvExistsBad(pszVar);
+}
+
+
+RTDECL(const char *) RTEnvGetBad(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, NULL);
+
+    IPRT_ALIGNMENT_CHECKS_DISABLE(); /* glibc causes trouble */
+    const char *pszValue = getenv(pszVar);
+    IPRT_ALIGNMENT_CHECKS_ENABLE();
+    return pszValue;
+}
+
+
+RTDECL(const char *) RTEnvGet(const char *pszVar)
+{
+    return RTEnvGetBad(pszVar);
+}
+
+
+RTDECL(int) RTEnvPutBad(const char *pszVarEqualValue)
+{
+    /** @todo putenv is a source memory leaks. deal with this on a per system basis. */
+    if (!putenv((char *)pszVarEqualValue))
+        return 0;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTEnvPut(const char *pszVarEqualValue)
+{
+    return RTEnvPutBad(pszVarEqualValue);
+}
+
+
+RTDECL(int) RTEnvSetBad(const char *pszVar, const char *pszValue)
+{
+    AssertMsgReturn(strchr(pszVar, '=') == NULL, ("'%s'\n", pszVar), VERR_ENV_INVALID_VAR_NAME);
+
+#if defined(_MSC_VER)
+    /* make a local copy and feed it to putenv. */
+    const size_t cchVar = strlen(pszVar);
+    const size_t cchValue = strlen(pszValue);
+    char *pszTmp = (char *)alloca(cchVar + cchValue + 2 + !*pszValue);
+    memcpy(pszTmp, pszVar, cchVar);
+    pszTmp[cchVar] = '=';
+    if (*pszValue)
+        memcpy(pszTmp + cchVar + 1, pszValue, cchValue + 1);
+    else
+    {
+        pszTmp[cchVar + 1] = ' '; /* wrong, but putenv will remove it otherwise. */
+        pszTmp[cchVar + 2] = '\0';
+    }
+
+    if (!putenv(pszTmp))
+        return 0;
+    return RTErrConvertFromErrno(errno);
+
+#else
+    if (!setenv(pszVar, pszValue, 1))
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+#endif
+}
+
+
+RTDECL(int) RTEnvSet(const char *pszVar, const char *pszValue)
+{
+    return RTEnvSetBad(pszVar, pszValue);
+}
+
+RTDECL(int) RTEnvUnsetBad(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, VERR_ENV_INVALID_VAR_NAME);
+
+    /*
+     * Check that it exists first.
+     */
+    if (!RTEnvExist(pszVar))
+        return VINF_ENV_VAR_NOT_FOUND;
+
+    /*
+     * Ok, try remove it.
+     */
+#ifdef RT_OS_WINDOWS
+    /* Use putenv(var=) since Windows does not have unsetenv(). */
+    size_t cchVar = strlen(pszVar);
+    char *pszBuf = (char *)alloca(cchVar + 2);
+    memcpy(pszBuf, pszVar, cchVar);
+    pszBuf[cchVar]     = '=';
+    pszBuf[cchVar + 1] = '\0';
+
+    if (!putenv(pszBuf))
+        return VINF_SUCCESS;
+
+#else
+    /* This is the preferred function as putenv() like used above does neither work on Solaris nor on Darwin. */
+    if (!unsetenv((char*)pszVar))
+        return VINF_SUCCESS;
+#endif
+
+    return RTErrConvertFromErrno(errno);
+}
+
+RTDECL(int) RTEnvUnset(const char *pszVar)
+{
+    return RTEnvUnsetBad(pszVar);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/errvars-posix.cpp b/src/VBox/Runtime/r3/posix/errvars-posix.cpp
new file mode 100644
index 00000000..b6a98709
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/errvars-posix.cpp
@@ -0,0 +1,88 @@
+/* $Id: errvars-posix.cpp $ */
+/** @file
+ * IPRT - Save and Restore Error Variables, POSIX Ring-3.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <netdb.h>
+#include <errno.h>
+
+#include <iprt/errcore.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include "internal/magics.h"
+
+
+
+RTDECL(PRTERRVARS) RTErrVarsSave(PRTERRVARS pVars)
+{
+    pVars->ai32Vars[0] = RTERRVARS_MAGIC;
+    pVars->ai32Vars[1] = errno;
+    pVars->ai32Vars[2] = h_errno;
+    return pVars;
+}
+
+
+RTDECL(void) RTErrVarsRestore(PCRTERRVARS pVars)
+{
+    AssertReturnVoid(pVars->ai32Vars[0] == RTERRVARS_MAGIC);
+    h_errno = pVars->ai32Vars[2];
+    errno = pVars->ai32Vars[1];
+}
+
+
+RTDECL(bool) RTErrVarsAreEqual(PCRTERRVARS pVars1, PCRTERRVARS pVars2)
+{
+    Assert(pVars1->ai32Vars[0] == RTERRVARS_MAGIC);
+    Assert(pVars2->ai32Vars[0] == RTERRVARS_MAGIC);
+
+    return pVars1->ai32Vars[0] == pVars2->ai32Vars[0]
+        && pVars1->ai32Vars[1] == pVars2->ai32Vars[1]
+        && pVars1->ai32Vars[2] == pVars2->ai32Vars[2];
+}
+
+
+RTDECL(bool) RTErrVarsHaveChanged(PCRTERRVARS pVars)
+{
+    Assert(pVars->ai32Vars[0] == RTERRVARS_MAGIC);
+
+    return pVars->ai32Vars[0] != RTERRVARS_MAGIC
+        || pVars->ai32Vars[1] != errno
+        || pVars->ai32Vars[2] != h_errno;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fileaio-posix.cpp b/src/VBox/Runtime/r3/posix/fileaio-posix.cpp
new file mode 100644
index 00000000..befa49fb
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileaio-posix.cpp
@@ -0,0 +1,1071 @@
+/* $Id: fileaio-posix.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for POSIX compliant host platforms.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/asm.h>
+#include <iprt/file.h>
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/thread.h>
+#include <iprt/semaphore.h>
+#include "internal/fileaio.h"
+
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+# include <sys/types.h>
+# include <sys/sysctl.h> /* for sysctlbyname */
+#endif
+#if defined(RT_OS_FREEBSD)
+# include <fcntl.h> /* O_SYNC */
+#endif
+#include <aio.h>
+#include <errno.h>
+#include <time.h>
+
+/*
+ * Linux does not define this value.
+ * Just define it with really big
+ * value.
+ */
+#ifndef AIO_LISTIO_MAX
+# define AIO_LISTIO_MAX UINT32_MAX
+#endif
+
+#if 0 /* Only used for debugging */
+# undef AIO_LISTIO_MAX
+# define AIO_LISTIO_MAX 16
+#endif
+
+/** Invalid entry in the waiting array. */
+#define RTFILEAIOCTX_WAIT_ENTRY_INVALID (~0U)
+
+/** No-op replacement for rtFileAioCtxDump for non debug builds */
+#ifndef LOG_ENABLED
+# define rtFileAioCtxDump(pCtxInt) do {} while (0)
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Async I/O request state.
+ */
+typedef struct RTFILEAIOREQINTERNAL
+{
+    /** The aio control block. FIRST ELEMENT! */
+    struct aiocb                 AioCB;
+    /** Next element in the chain. */
+    struct RTFILEAIOREQINTERNAL *pNext;
+    /** Previous element in the chain. */
+    struct RTFILEAIOREQINTERNAL *pPrev;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE            enmState;
+    /** Flag whether this is a flush request. */
+    bool                         fFlush;
+    /** Flag indicating if the request was canceled. */
+    volatile bool                fCanceled;
+    /** Opaque user data. */
+    void                        *pvUser;
+    /** Number of bytes actually transferred. */
+    size_t                       cbTransfered;
+    /** Status code. */
+    int                          Rc;
+    /** Completion context we are assigned to. */
+    struct RTFILEAIOCTXINTERNAL *pCtxInt;
+    /** Entry in the waiting list the request is in. */
+    unsigned                     iWaitingList;
+    /** Magic value  (RTFILEAIOREQ_MAGIC). */
+    uint32_t                     u32Magic;
+} RTFILEAIOREQINTERNAL, *PRTFILEAIOREQINTERNAL;
+
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** Current number of requests active on this context. */
+    volatile int32_t      cRequests;
+    /** Maximum number of requests this context can handle. */
+    uint32_t              cMaxRequests;
+    /** The ID of the thread which is currently waiting for requests. */
+    volatile RTTHREAD     hThreadWait;
+    /** Flag whether the thread was woken up. */
+    volatile bool         fWokenUp;
+    /** Flag whether the thread is currently waiting in the syscall. */
+    volatile bool         fWaiting;
+    /** Flags given during creation. */
+    uint32_t              fFlags;
+    /** Magic value (RTFILEAIOCTX_MAGIC). */
+    uint32_t              u32Magic;
+    /** Flag whether the thread was woken up due to a internal event. */
+    volatile bool         fWokenUpInternal;
+    /** List of new requests which needs to be inserted into apReqs by the
+     *  waiting thread. */
+    volatile PRTFILEAIOREQINTERNAL apReqsNewHead[5];
+    /** Special entry for requests which are canceled. Because only one
+     * request can be canceled at a time and the thread canceling the request
+     * has to wait we need only one entry. */
+    volatile PRTFILEAIOREQINTERNAL pReqToCancel;
+    /** Event semaphore the canceling thread is waiting for completion of
+     * the operation. */
+    RTSEMEVENT            SemEventCancel;
+    /** Head of submitted elements waiting to get into the array. */
+    PRTFILEAIOREQINTERNAL pReqsWaitHead;
+    /** Tail of submitted elements waiting to get into the array. */
+    PRTFILEAIOREQINTERNAL pReqsWaitTail;
+    /** Maximum number of elements in the waiting array. */
+    unsigned              cReqsWaitMax;
+    /** First free slot in the waiting list. */
+    unsigned              iFirstFree;
+    /** List of requests we are currently waiting on.
+     * Size depends on cMaxRequests and AIO_LISTIO_MAX. */
+    volatile PRTFILEAIOREQINTERNAL apReqs[1];
+} RTFILEAIOCTXINTERNAL, *PRTFILEAIOCTXINTERNAL;
+
+/**
+ * Internal worker for waking up the waiting thread.
+ */
+static void rtFileAioCtxWakeup(PRTFILEAIOCTXINTERNAL pCtxInt)
+{
+    /*
+     * Read the thread handle before the status flag.
+     * If we read the handle after the flag we might
+     * end up with an invalid handle because the thread
+     * waiting in RTFileAioCtxWakeup() might get scheduled
+     * before we read the flag and returns.
+     * We can ensure that the handle is valid if fWaiting is true
+     * when reading the handle before the status flag.
+     */
+    RTTHREAD hThread;
+    ASMAtomicReadHandle(&pCtxInt->hThreadWait, &hThread);
+    bool fWaiting = ASMAtomicReadBool(&pCtxInt->fWaiting);
+    if (fWaiting)
+    {
+        /*
+         * If a thread waits the handle must be valid.
+         * It is possible that the thread returns from
+         * aio_suspend() before the signal is send.
+         * This is no problem because we already set fWokenUp
+         * to true which will let the thread return VERR_INTERRUPTED
+         * and the next call to RTFileAioCtxWait() will not
+         * return VERR_INTERRUPTED because signals are not saved
+         * and will simply vanish if the destination thread can't
+         * receive it.
+         */
+        Assert(hThread != NIL_RTTHREAD);
+        RTThreadPoke(hThread);
+    }
+}
+
+/**
+ * Internal worker processing events and inserting new requests into the waiting list.
+ */
+static int rtFileAioCtxProcessEvents(PRTFILEAIOCTXINTERNAL pCtxInt)
+{
+    int rc = VINF_SUCCESS;
+
+    /* Process new requests first. */
+    bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUpInternal, false);
+    if (fWokenUp)
+    {
+        for (unsigned iSlot = 0; iSlot < RT_ELEMENTS(pCtxInt->apReqsNewHead); iSlot++)
+        {
+            PRTFILEAIOREQINTERNAL pReqHead = ASMAtomicXchgPtrT(&pCtxInt->apReqsNewHead[iSlot], NULL, PRTFILEAIOREQINTERNAL);
+
+            while (  (pCtxInt->iFirstFree < pCtxInt->cReqsWaitMax)
+                   && pReqHead)
+            {
+                RTFIELAIOREQ_ASSERT_STATE(pReqHead, SUBMITTED);
+                pCtxInt->apReqs[pCtxInt->iFirstFree] = pReqHead;
+                pReqHead->iWaitingList = pCtxInt->iFirstFree;
+                pReqHead = pReqHead->pNext;
+
+                /* Clear pointer to next and previous element just for safety. */
+                pCtxInt->apReqs[pCtxInt->iFirstFree]->pNext = NULL;
+                pCtxInt->apReqs[pCtxInt->iFirstFree]->pPrev = NULL;
+                pCtxInt->iFirstFree++;
+
+                Assert(   (pCtxInt->iFirstFree <= pCtxInt->cMaxRequests)
+                       && (pCtxInt->iFirstFree <= pCtxInt->cReqsWaitMax));
+            }
+
+            /* Append the rest to the wait list. */
+            if (pReqHead)
+            {
+                RTFIELAIOREQ_ASSERT_STATE(pReqHead, SUBMITTED);
+                if (!pCtxInt->pReqsWaitHead)
+                {
+                    Assert(!pCtxInt->pReqsWaitTail);
+                    pCtxInt->pReqsWaitHead = pReqHead;
+                    pReqHead->pPrev = NULL;
+                }
+                else
+                {
+                    AssertPtr(pCtxInt->pReqsWaitTail);
+
+                    pCtxInt->pReqsWaitTail->pNext = pReqHead;
+                    pReqHead->pPrev = pCtxInt->pReqsWaitTail;
+                }
+
+                /* Update tail. */
+                while (pReqHead->pNext)
+                {
+                    RTFIELAIOREQ_ASSERT_STATE(pReqHead->pNext, SUBMITTED);
+                    pReqHead = pReqHead->pNext;
+                }
+
+                pCtxInt->pReqsWaitTail = pReqHead;
+                pCtxInt->pReqsWaitTail->pNext = NULL;
+            }
+        }
+
+        /* Check if a request needs to be canceled. */
+        PRTFILEAIOREQINTERNAL pReqToCancel = ASMAtomicReadPtrT(&pCtxInt->pReqToCancel, PRTFILEAIOREQINTERNAL);
+        if (pReqToCancel)
+        {
+            /* The request can be in the array waiting for completion or still in the list because it is full. */
+            if (pReqToCancel->iWaitingList != RTFILEAIOCTX_WAIT_ENTRY_INVALID)
+            {
+                /* Put it out of the waiting list. */
+                pCtxInt->apReqs[pReqToCancel->iWaitingList] = pCtxInt->apReqs[--pCtxInt->iFirstFree];
+                pCtxInt->apReqs[pReqToCancel->iWaitingList]->iWaitingList = pReqToCancel->iWaitingList;
+            }
+            else
+            {
+                /* Unlink from the waiting list. */
+                PRTFILEAIOREQINTERNAL pPrev = pReqToCancel->pPrev;
+                PRTFILEAIOREQINTERNAL pNext = pReqToCancel->pNext;
+
+                if (pNext)
+                    pNext->pPrev = pPrev;
+                else
+                {
+                    /* We canceled the tail. */
+                    pCtxInt->pReqsWaitTail = pPrev;
+                }
+
+                if (pPrev)
+                    pPrev->pNext = pNext;
+                else
+                {
+                    /* We canceled the head. */
+                    pCtxInt->pReqsWaitHead = pNext;
+                }
+            }
+
+            ASMAtomicDecS32(&pCtxInt->cRequests);
+            AssertMsg(pCtxInt->cRequests >= 0, ("Canceled request not which is not in this context\n"));
+            RTSemEventSignal(pCtxInt->SemEventCancel);
+        }
+    }
+    else
+    {
+        if (ASMAtomicXchgBool(&pCtxInt->fWokenUp, false))
+            rc = VERR_INTERRUPTED;
+    }
+
+    return rc;
+}
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    int rcBSD = 0;
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+#if defined(RT_OS_DARWIN)
+    int cReqsOutstandingMax = 0;
+    size_t cbParameter = sizeof(int);
+
+    rcBSD = sysctlbyname("kern.aioprocmax",     /* name */
+                         &cReqsOutstandingMax,  /* Where to store the old value. */
+                         &cbParameter,          /* Size of the memory pointed to. */
+                         NULL,                  /* Where the new value is located. */
+                         0);                    /* Where the size of the new value is stored. */
+    if (rcBSD == -1)
+        return RTErrConvertFromErrno(errno);
+
+    pAioLimits->cReqsOutstandingMax = cReqsOutstandingMax;
+    pAioLimits->cbBufferAlignment   = 0;
+#elif defined(RT_OS_FREEBSD)
+    /*
+     * The AIO API is implemented in a kernel module which is not
+     * loaded by default.
+     * If it is loaded there are additional sysctl parameters.
+     */
+    int cReqsOutstandingMax = 0;
+    size_t cbParameter = sizeof(int);
+
+    rcBSD = sysctlbyname("vfs.aio.max_aio_per_proc", /* name */
+                         &cReqsOutstandingMax,       /* Where to store the old value. */
+                         &cbParameter,               /* Size of the memory pointed to. */
+                         NULL,                       /* Where the new value is located. */
+                         0);                         /* Where the size of the new value is stored. */
+    if (rcBSD == -1)
+    {
+        /* ENOENT means the value is unknown thus the module is not loaded. */
+        if (errno == ENOENT)
+            return VERR_NOT_SUPPORTED;
+        else
+            return RTErrConvertFromErrno(errno);
+    }
+
+    pAioLimits->cReqsOutstandingMax = cReqsOutstandingMax;
+    pAioLimits->cbBufferAlignment   = 0;
+#else
+    pAioLimits->cReqsOutstandingMax = RTFILEAIO_UNLIMITED_REQS;
+    pAioLimits->cbBufferAlignment   = 0;
+#endif
+
+    return VINF_SUCCESS;
+}
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOREQINTERNAL));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    pReqInt->pCtxInt      = NULL;
+    pReqInt->u32Magic     = RTFILEAIOREQ_MAGIC;
+    pReqInt->iWaitingList = RTFILEAIOCTX_WAIT_ENTRY_INVALID;
+    RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+    *phReq = (RTFILEAIOREQ)pReqInt;
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
+{
+    /*
+     * Validate the handle and ignore nil.
+     */
+    if (hReq == NIL_RTFILEAIOREQ)
+        return VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    /*
+     * Trash the magic and free it.
+     */
+    ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
+    RTMemFree(pReqInt);
+    return VINF_SUCCESS;
+}
+
+/**
+ * Worker setting up the request.
+ */
+DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
+                                            unsigned uTransferDirection,
+                                            RTFOFF off, void *pvBuf, size_t cbTransfer,
+                                            void *pvUser)
+{
+    /*
+     * Validate the input.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+    AssertPtr(pvBuf);
+    Assert(off >= 0);
+    Assert(cbTransfer > 0);
+
+    memset(&pReqInt->AioCB, 0, sizeof(struct aiocb));
+    pReqInt->fFlush               = false;
+    pReqInt->AioCB.aio_lio_opcode = uTransferDirection;
+    pReqInt->AioCB.aio_fildes     = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset     = off;
+    pReqInt->AioCB.aio_nbytes     = cbTransfer;
+    pReqInt->AioCB.aio_buf        = pvBuf;
+    pReqInt->pvUser               = pvUser;
+    pReqInt->pCtxInt              = NULL;
+    pReqInt->Rc                   = VERR_FILE_AIO_IN_PROGRESS;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                    void *pvBuf, size_t cbRead, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_READ,
+                                       off, pvBuf, cbRead, pvUser);
+}
+
+
+RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                     void const *pvBuf, size_t cbWrite, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)hReq;
+
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+
+    pReqInt->fFlush           = true;
+    pReqInt->AioCB.aio_fildes = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset = 0;
+    pReqInt->AioCB.aio_nbytes = 0;
+    pReqInt->AioCB.aio_buf    = NULL;
+    pReqInt->pvUser           = pvUser;
+    pReqInt->Rc               = VERR_FILE_AIO_IN_PROGRESS;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->pvUser;
+}
+
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    ASMAtomicXchgBool(&pReqInt->fCanceled, true);
+
+    int rcPosix = aio_cancel(pReqInt->AioCB.aio_fildes, &pReqInt->AioCB);
+
+    if (rcPosix == AIO_CANCELED)
+    {
+        PRTFILEAIOCTXINTERNAL pCtxInt = pReqInt->pCtxInt;
+        /*
+         * Notify the waiting thread that the request was canceled.
+         */
+        AssertMsg(RT_VALID_PTR(pCtxInt), ("Invalid state. Request was canceled but wasn't submitted\n"));
+
+        Assert(!pCtxInt->pReqToCancel);
+        ASMAtomicWritePtr(&pCtxInt->pReqToCancel, pReqInt);
+        rtFileAioCtxWakeup(pCtxInt);
+
+        /* Wait for acknowledge. */
+        int rc = RTSemEventWait(pCtxInt->SemEventCancel, RT_INDEFINITE_WAIT);
+        AssertRC(rc);
+
+        ASMAtomicWriteNullPtr(&pCtxInt->pReqToCancel);
+        pReqInt->Rc = VERR_FILE_AIO_CANCELED;
+        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+        return VINF_SUCCESS;
+    }
+    else if (rcPosix == AIO_ALLDONE)
+        return VERR_FILE_AIO_COMPLETED;
+    else if (rcPosix == AIO_NOTCANCELED)
+        return VERR_FILE_AIO_IN_PROGRESS;
+    else
+        return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
+    AssertPtrNull(pcbTransfered);
+
+    if (  (RT_SUCCESS(pReqInt->Rc))
+        && (pcbTransfered))
+        *pcbTransfered = pReqInt->cbTransfered;
+
+    return pReqInt->Rc;
+}
+
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
+                               uint32_t fFlags)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    unsigned cReqsWaitMax;
+
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    if (cAioReqsMax == RTFILEAIO_UNLIMITED_REQS)
+        return VERR_OUT_OF_RANGE;
+
+    cReqsWaitMax = RT_MIN(cAioReqsMax, AIO_LISTIO_MAX);
+
+    pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(  sizeof(RTFILEAIOCTXINTERNAL)
+                                                 + cReqsWaitMax * sizeof(PRTFILEAIOREQINTERNAL));
+    if (RT_UNLIKELY(!pCtxInt))
+        return VERR_NO_MEMORY;
+
+    /* Create event semaphore. */
+    int rc = RTSemEventCreate(&pCtxInt->SemEventCancel);
+    if (RT_FAILURE(rc))
+    {
+        RTMemFree(pCtxInt);
+        return rc;
+    }
+
+    pCtxInt->u32Magic     = RTFILEAIOCTX_MAGIC;
+    pCtxInt->cMaxRequests = cAioReqsMax;
+    pCtxInt->cReqsWaitMax = cReqsWaitMax;
+    pCtxInt->fFlags       = fFlags;
+    *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+
+    AssertPtrReturn(pCtxInt, VERR_INVALID_HANDLE);
+
+    if (RT_UNLIKELY(pCtxInt->cRequests))
+        return VERR_FILE_AIO_BUSY;
+
+    RTSemEventDestroy(pCtxInt->SemEventCancel);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return RTFILEAIO_UNLIMITED_REQS;
+    return pCtxInt->cMaxRequests;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    NOREF(hAioCtx); NOREF(hFile);
+    return VINF_SUCCESS;
+}
+
+#ifdef LOG_ENABLED
+/**
+ * Dumps the state of a async I/O context.
+ */
+static void rtFileAioCtxDump(PRTFILEAIOCTXINTERNAL pCtxInt)
+{
+    LogFlow(("cRequests=%d\n", pCtxInt->cRequests));
+    LogFlow(("cMaxRequests=%u\n", pCtxInt->cMaxRequests));
+    LogFlow(("hThreadWait=%#p\n", pCtxInt->hThreadWait));
+    LogFlow(("fWokenUp=%RTbool\n", pCtxInt->fWokenUp));
+    LogFlow(("fWaiting=%RTbool\n", pCtxInt->fWaiting));
+    LogFlow(("fWokenUpInternal=%RTbool\n", pCtxInt->fWokenUpInternal));
+    for (unsigned i = 0; i < RT_ELEMENTS(pCtxInt->apReqsNewHead); i++)
+        LogFlow(("apReqsNewHead[%u]=%#p\n", i, pCtxInt->apReqsNewHead[i]));
+    LogFlow(("pReqToCancel=%#p\n", pCtxInt->pReqToCancel));
+    LogFlow(("pReqsWaitHead=%#p\n", pCtxInt->pReqsWaitHead));
+    LogFlow(("pReqsWaitTail=%#p\n", pCtxInt->pReqsWaitTail));
+    LogFlow(("cReqsWaitMax=%u\n", pCtxInt->cReqsWaitMax));
+    LogFlow(("iFirstFree=%u\n", pCtxInt->iFirstFree));
+    for (unsigned i = 0; i < pCtxInt->cReqsWaitMax; i++)
+        LogFlow(("apReqs[%u]=%#p\n", i, pCtxInt->apReqs[i]));
+}
+#endif
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+
+    /* Parameter checks */
+    AssertPtrReturn(pCtxInt, VERR_INVALID_HANDLE);
+    AssertReturn(cReqs != 0, VERR_INVALID_POINTER);
+    AssertPtrReturn(pahReqs,  VERR_INVALID_PARAMETER);
+
+    rtFileAioCtxDump(pCtxInt);
+
+    /* Check that we don't exceed the limit */
+    if (ASMAtomicUoReadS32(&pCtxInt->cRequests) + cReqs > pCtxInt->cMaxRequests)
+        return VERR_FILE_AIO_LIMIT_EXCEEDED;
+
+    PRTFILEAIOREQINTERNAL pHead = NULL;
+
+    do
+    {
+        int rcPosix = 0;
+        size_t cReqsSubmit = 0;
+        size_t i = 0;
+        PRTFILEAIOREQINTERNAL pReqInt;
+
+        while (   (i < cReqs)
+               && (i < AIO_LISTIO_MAX))
+        {
+            pReqInt = pahReqs[i];
+            if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
+            {
+                /* Undo everything and stop submitting. */
+                for (size_t iUndo = 0; iUndo < i; iUndo++)
+                {
+                    pReqInt = pahReqs[iUndo];
+                    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                    pReqInt->pCtxInt = NULL;
+
+                    /* Unlink from the list again. */
+                    PRTFILEAIOREQINTERNAL pNext, pPrev;
+                    pNext = pReqInt->pNext;
+                    pPrev = pReqInt->pPrev;
+                    if (pNext)
+                        pNext->pPrev = pPrev;
+                    if (pPrev)
+                        pPrev->pNext = pNext;
+                    else
+                        pHead = pNext;
+                }
+                rc = VERR_INVALID_HANDLE;
+                break;
+            }
+
+            pReqInt->pCtxInt = pCtxInt;
+
+            if (pReqInt->fFlush)
+                break;
+
+            /* Link them together. */
+            pReqInt->pNext = pHead;
+            if (pHead)
+                pHead->pPrev = pReqInt;
+            pReqInt->pPrev = NULL;
+            pHead = pReqInt;
+            RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+
+            cReqsSubmit++;
+            i++;
+        }
+
+        if (cReqsSubmit)
+        {
+            rcPosix = lio_listio(LIO_NOWAIT, (struct aiocb **)pahReqs, cReqsSubmit, NULL);
+            if (RT_UNLIKELY(rcPosix < 0))
+            {
+                size_t cReqsSubmitted = cReqsSubmit;
+
+                if (errno == EAGAIN)
+                    rc = VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+
+                /* Check which ones were not submitted. */
+                for (i = 0; i < cReqsSubmit; i++)
+                {
+                    pReqInt = pahReqs[i];
+
+                    rcPosix = aio_error(&pReqInt->AioCB);
+
+                    if ((rcPosix != EINPROGRESS) && (rcPosix != 0))
+                    {
+                        cReqsSubmitted--;
+
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+                        if (errno == EINVAL)
+#else
+                        if (rcPosix == EINVAL)
+#endif
+                        {
+                            /* Was not submitted. */
+                            RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                        }
+                        else
+                        {
+                            /* An error occurred. */
+                            RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+                            /*
+                             * Looks like Apple and glibc interpret the standard in different ways.
+                             * glibc returns the error code which would be in errno but Apple returns
+                             * -1 and sets errno to the appropriate value
+                             */
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+                            Assert(rcPosix == -1);
+                            pReqInt->Rc = RTErrConvertFromErrno(errno);
+#elif defined(RT_OS_LINUX)
+                            pReqInt->Rc = RTErrConvertFromErrno(rcPosix);
+#endif
+                            pReqInt->cbTransfered = 0;
+                        }
+                        /* Unlink from the list. */
+                        PRTFILEAIOREQINTERNAL pNext, pPrev;
+                        pNext = pReqInt->pNext;
+                        pPrev = pReqInt->pPrev;
+                        if (pNext)
+                            pNext->pPrev = pPrev;
+                        if (pPrev)
+                            pPrev->pNext = pNext;
+                        else
+                            pHead = pNext;
+
+                        pReqInt->pNext = NULL;
+                        pReqInt->pPrev = NULL;
+                    }
+                }
+                ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmitted);
+                AssertMsg(pCtxInt->cRequests >= 0, ("Adding requests resulted in overflow\n"));
+                break;
+            }
+
+            ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmit);
+            AssertMsg(pCtxInt->cRequests >= 0, ("Adding requests resulted in overflow\n"));
+            cReqs   -= cReqsSubmit;
+            pahReqs += cReqsSubmit;
+        }
+
+        /*
+         * Check if we have a flush request now.
+         * If not we hit the AIO_LISTIO_MAX limit
+         * and will continue submitting requests
+         * above.
+         */
+        if (cReqs && RT_SUCCESS_NP(rc))
+        {
+            pReqInt = pahReqs[0];
+
+            if (pReqInt->fFlush)
+            {
+                /*
+                 * lio_listio does not work with flush requests so
+                 * we have to use aio_fsync directly.
+                 */
+                rcPosix = aio_fsync(O_SYNC, &pReqInt->AioCB);
+                if (RT_UNLIKELY(rcPosix < 0))
+                {
+                    if (errno == EAGAIN)
+                    {
+                        rc = VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+                        RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                    }
+                    else
+                    {
+                        rc = RTErrConvertFromErrno(errno);
+                        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                        pReqInt->Rc = rc;
+                    }
+                    pReqInt->cbTransfered = 0;
+                    break;
+                }
+
+                /* Link them together. */
+                pReqInt->pNext = pHead;
+                if (pHead)
+                    pHead->pPrev = pReqInt;
+                pReqInt->pPrev = NULL;
+                pHead = pReqInt;
+                RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+
+                ASMAtomicIncS32(&pCtxInt->cRequests);
+                AssertMsg(pCtxInt->cRequests >= 0, ("Adding requests resulted in overflow\n"));
+                cReqs--;
+                pahReqs++;
+            }
+        }
+    } while (   cReqs
+             && RT_SUCCESS_NP(rc));
+
+    if (pHead)
+    {
+        /*
+         * Forward successfully submitted requests to the thread waiting for requests.
+         * We search for a free slot first and if we don't find one
+         * we will grab the first one and append our list to the existing entries.
+         */
+        unsigned iSlot = 0;
+        while (  (iSlot < RT_ELEMENTS(pCtxInt->apReqsNewHead))
+               && !ASMAtomicCmpXchgPtr(&pCtxInt->apReqsNewHead[iSlot], pHead, NULL))
+            iSlot++;
+
+        if (iSlot == RT_ELEMENTS(pCtxInt->apReqsNewHead))
+        {
+            /* Nothing found. */
+            PRTFILEAIOREQINTERNAL pOldHead = ASMAtomicXchgPtrT(&pCtxInt->apReqsNewHead[0], NULL, PRTFILEAIOREQINTERNAL);
+
+            /* Find the end of the current head and link the old list to the current. */
+            PRTFILEAIOREQINTERNAL pTail = pHead;
+            while (pTail->pNext)
+                pTail = pTail->pNext;
+
+            pTail->pNext = pOldHead;
+
+            ASMAtomicWritePtr(&pCtxInt->apReqsNewHead[0], pHead);
+        }
+
+        /* Set the internal wakeup flag and wakeup the thread if possible. */
+        bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUpInternal, true);
+        if (!fWokenUp)
+            rtFileAioCtxWakeup(pCtxInt);
+    }
+
+    rtFileAioCtxDump(pCtxInt);
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+    PRTFILEAIOCTXINTERNAL pCtxInt = (PRTFILEAIOCTXINTERNAL)hAioCtx;
+    struct timespec Timeout;
+    struct timespec *pTimeout = NULL;
+    uint64_t         StartNanoTS = 0;
+
+    LogFlowFunc(("hAioCtx=%#p cMinReqs=%zu cMillies=%u pahReqs=%#p cReqs=%zu pcbReqs=%#p\n",
+                 hAioCtx, cMinReqs, cMillies, pahReqs, cReqs, pcReqs));
+
+    /* Check parameters. */
+    AssertPtrReturn(pCtxInt, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
+    AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
+
+    rtFileAioCtxDump(pCtxInt);
+
+    int32_t cRequestsWaiting = ASMAtomicReadS32(&pCtxInt->cRequests);
+
+    if (   RT_UNLIKELY(cRequestsWaiting <= 0)
+        && !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
+        return VERR_FILE_AIO_NO_REQUEST;
+
+    if (RT_UNLIKELY(cMinReqs > (uint32_t)cRequestsWaiting))
+        return VERR_INVALID_PARAMETER;
+
+    if (cMillies != RT_INDEFINITE_WAIT)
+    {
+        Timeout.tv_sec  = cMillies / 1000;
+        Timeout.tv_nsec = (cMillies % 1000) * 1000000;
+        pTimeout = &Timeout;
+        StartNanoTS = RTTimeNanoTS();
+    }
+
+    /* Wait for at least one. */
+    if (!cMinReqs)
+        cMinReqs = 1;
+
+    /* For the wakeup call. */
+    Assert(pCtxInt->hThreadWait == NIL_RTTHREAD);
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, RTThreadSelf());
+
+    /* Update the waiting list once before we enter the loop. */
+    rc = rtFileAioCtxProcessEvents(pCtxInt);
+
+    while (   cMinReqs
+           && RT_SUCCESS_NP(rc))
+    {
+#ifdef RT_STRICT
+        if (RT_UNLIKELY(!pCtxInt->iFirstFree))
+        {
+            for (unsigned i = 0; i < pCtxInt->cReqsWaitMax; i++)
+                RTAssertMsg2Weak("wait[%d] = %#p\n", i, pCtxInt->apReqs[i]);
+
+            AssertMsgFailed(("No request to wait for. pReqsWaitHead=%#p pReqsWaitTail=%#p\n",
+                            pCtxInt->pReqsWaitHead, pCtxInt->pReqsWaitTail));
+        }
+#endif
+
+        LogFlow(("Waiting for %d requests to complete\n", pCtxInt->iFirstFree));
+        rtFileAioCtxDump(pCtxInt);
+
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
+        int rcPosix = aio_suspend((const struct aiocb * const *)pCtxInt->apReqs,
+                                  pCtxInt->iFirstFree, pTimeout);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
+        if (rcPosix < 0)
+        {
+            LogFlow(("aio_suspend failed %d nent=%u\n", errno, pCtxInt->iFirstFree));
+            /* Check that this is an external wakeup event. */
+            if (errno == EINTR)
+                rc = rtFileAioCtxProcessEvents(pCtxInt);
+            else
+                rc = RTErrConvertFromErrno(errno);
+        }
+        else
+        {
+            /* Requests finished. */
+            unsigned iReqCurr = 0;
+            unsigned cDone = 0;
+
+            /* Remove completed requests from the waiting list. */
+            while (   (iReqCurr < pCtxInt->iFirstFree)
+                   && (cDone < cReqs))
+            {
+                PRTFILEAIOREQINTERNAL pReq = pCtxInt->apReqs[iReqCurr];
+                int rcReq = aio_error(&pReq->AioCB);
+
+                if (rcReq != EINPROGRESS)
+                {
+                    /* Completed store the return code. */
+                    if (rcReq == 0)
+                    {
+                        pReq->Rc = VINF_SUCCESS;
+                        /* Call aio_return() to free resources. */
+                        pReq->cbTransfered = aio_return(&pReq->AioCB);
+                    }
+                    else
+                    {
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+                        pReq->Rc = RTErrConvertFromErrno(errno);
+#else
+                        pReq->Rc = RTErrConvertFromErrno(rcReq);
+#endif
+                    }
+
+                    /* Mark the request as finished. */
+                    RTFILEAIOREQ_SET_STATE(pReq, COMPLETED);
+                    cDone++;
+
+                    /* If there are other entries waiting put the head into the now free entry. */
+                    if (pCtxInt->pReqsWaitHead)
+                    {
+                        PRTFILEAIOREQINTERNAL pReqInsert = pCtxInt->pReqsWaitHead;
+
+                        pCtxInt->pReqsWaitHead = pReqInsert->pNext;
+                        if (!pCtxInt->pReqsWaitHead)
+                        {
+                            /* List is empty now. Clear tail too. */
+                            pCtxInt->pReqsWaitTail = NULL;
+                        }
+
+                        pReqInsert->iWaitingList = pReq->iWaitingList;
+                        pCtxInt->apReqs[pReqInsert->iWaitingList] = pReqInsert;
+                        iReqCurr++;
+                    }
+                    else
+                    {
+                        /*
+                         * Move the last entry into the current position to avoid holes
+                         * but only if it is not the last element already.
+                         */
+                        if (pReq->iWaitingList < pCtxInt->iFirstFree - 1)
+                        {
+                            pCtxInt->apReqs[pReq->iWaitingList] = pCtxInt->apReqs[--pCtxInt->iFirstFree];
+                            pCtxInt->apReqs[pReq->iWaitingList]->iWaitingList = pReq->iWaitingList;
+                        }
+                        else
+                            pCtxInt->iFirstFree--;
+
+                        pCtxInt->apReqs[pCtxInt->iFirstFree] = NULL;
+                    }
+
+                    /* Put the request into the completed list. */
+                    pahReqs[cRequestsCompleted++] = pReq;
+                    pReq->iWaitingList = RTFILEAIOCTX_WAIT_ENTRY_INVALID;
+                }
+                else
+                    iReqCurr++;
+            }
+
+            AssertMsg((cDone <= cReqs), ("Overflow cReqs=%u cMinReqs=%u cDone=%u\n",
+                                         cReqs, cDone));
+            cReqs    -= cDone;
+            cMinReqs  = RT_MAX(cMinReqs, cDone) - cDone;
+            ASMAtomicSubS32(&pCtxInt->cRequests, cDone);
+
+            AssertMsg(pCtxInt->cRequests >= 0, ("Finished more requests than currently active\n"));
+
+            if (!cMinReqs)
+                break;
+
+            if (cMillies != RT_INDEFINITE_WAIT)
+            {
+                uint64_t TimeDiff;
+
+                /* Recalculate the timeout. */
+                TimeDiff = RTTimeSystemNanoTS() - StartNanoTS;
+                Timeout.tv_sec  = Timeout.tv_sec  - (TimeDiff / 1000000);
+                Timeout.tv_nsec = Timeout.tv_nsec - (TimeDiff % 1000000);
+            }
+
+            /* Check for new elements. */
+            rc = rtFileAioCtxProcessEvents(pCtxInt);
+        }
+    }
+
+    *pcReqs = cRequestsCompleted;
+    Assert(pCtxInt->hThreadWait == RTThreadSelf());
+    ASMAtomicWriteHandle(&pCtxInt->hThreadWait, NIL_RTTHREAD);
+
+    rtFileAioCtxDump(pCtxInt);
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /** @todo r=bird: Define the protocol for how to resume work after calling
+     *        this function. */
+
+    bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUp, true);
+    if (!fWokenUp)
+        rtFileAioCtxWakeup(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fileio-at-posix.cpp b/src/VBox/Runtime/r3/posix/fileio-at-posix.cpp
new file mode 100644
index 00000000..72d3cc05
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileio-at-posix.cpp
@@ -0,0 +1,107 @@
+/* $Id: fileio-at-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, RTFileReadAt and RTFileWriteAt, posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <errno.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/err.h>
+#include <iprt/log.h>
+
+
+
+RTDECL(int)  RTFileReadAt(RTFILE hFile, RTFOFF off, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    ssize_t cbRead = pread(RTFileToNative(hFile), pvBuf, cbToRead, off);
+    if (cbRead >= 0)
+    {
+        if (pcbRead)
+            /* caller can handle partial read. */
+            *pcbRead = cbRead;
+        else
+        {
+            /* Caller expects all to be read. */
+            while ((ssize_t)cbToRead > cbRead)
+            {
+                ssize_t cbReadPart = pread(RTFileToNative(hFile), (char*)pvBuf + cbRead, cbToRead - cbRead, off + cbRead);
+                if (cbReadPart <= 0)
+                {
+                    if (cbReadPart == 0)
+                        return VERR_EOF;
+                    return RTErrConvertFromErrno(errno);
+                }
+                cbRead += cbReadPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int)  RTFileWriteAt(RTFILE hFile, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    ssize_t cbWritten = pwrite(RTFileToNative(hFile), pvBuf, cbToWrite, off);
+    if (cbWritten >= 0)
+    {
+        if (pcbWritten)
+            /* caller can handle partial write. */
+            *pcbWritten = cbWritten;
+        else
+        {
+            /* Caller expects all to be write. */
+            while ((ssize_t)cbToWrite > cbWritten)
+            {
+                ssize_t cbWrittenPart = pwrite(RTFileToNative(hFile), (const char *)pvBuf + cbWritten, cbToWrite - cbWritten,
+                                               off + cbWritten);
+                if (cbWrittenPart < 0)
+                    return cbWrittenPart < 0 ? RTErrConvertFromErrno(errno) : VERR_TRY_AGAIN;
+                cbWritten += cbWrittenPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fileio-posix.cpp b/src/VBox/Runtime/r3/posix/fileio-posix.cpp
new file mode 100644
index 00000000..cd7d238f
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileio-posix.cpp
@@ -0,0 +1,934 @@
+/* $Id: fileio-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, POSIX, Part 1.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#ifdef _MSC_VER
+# include <io.h>
+# include <stdio.h>
+#else
+# include <unistd.h>
+# include <sys/time.h>
+#endif
+#ifdef RT_OS_LINUX
+# include <sys/file.h>
+#endif
+#if defined(RT_OS_OS2) && (!defined(__INNOTEK_LIBC__) || __INNOTEK_LIBC__ < 0x006)
+# include <io.h>
+#endif
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+# include <sys/disk.h>
+#endif
+#ifdef RT_OS_SOLARIS
+# include <stropts.h>
+# include <sys/dkio.h>
+# include <sys/vtoc.h>
+#endif /* RT_OS_SOLARIS */
+
+#include <iprt/file.h>
+#include <iprt/path.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/thread.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Default file permissions for newly created files. */
+#if defined(S_IRUSR) && defined(S_IWUSR)
+# define RT_FILE_PERMISSION  (S_IRUSR | S_IWUSR)
+#else
+# define RT_FILE_PERMISSION  (00600)
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef O_CLOEXEC
+static int volatile g_fHave_O_CLOEXEC = 0; /* {-1,0,1}; since Linux 2.6.23 */
+#endif
+
+
+
+RTDECL(bool) RTFileExists(const char *pszPath)
+{
+    bool fRc = false;
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat s;
+        fRc = !stat(pszNativePath, &s)
+            && S_ISREG(s.st_mode);
+
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTFileExists(%p={%s}): returns %RTbool\n", pszPath, pszPath, fRc));
+    return fRc;
+}
+
+
+#ifdef O_CLOEXEC
+/** Worker for RTFileOpenEx that detects whether the kernel supports
+ *  O_CLOEXEC or not, setting g_fHave_O_CLOEXEC to 1 or -1 accordingly. */
+static int rtFileOpenExDetectCloExecSupport(void)
+{
+    /*
+     * Open /dev/null with O_CLOEXEC and see if FD_CLOEXEC is set or not.
+     */
+    int fHave_O_CLOEXEC = -1;
+    int fd = open("/dev/null", O_RDONLY | O_CLOEXEC, 0);
+    if (fd >= 0)
+    {
+        int fFlags = fcntl(fd, F_GETFD, 0);
+        fHave_O_CLOEXEC = fFlags > 0 && (fFlags & FD_CLOEXEC) ? 1 : -1;
+        close(fd);
+    }
+    else
+        AssertMsg(errno == EINVAL, ("%d\n", errno));
+    g_fHave_O_CLOEXEC = fHave_O_CLOEXEC;
+    return fHave_O_CLOEXEC;
+}
+#endif
+
+
+RTR3DECL(int) RTFileOpen(PRTFILE pFile, const char *pszFilename, uint64_t fOpen)
+{
+    return RTFileOpenEx(pszFilename, fOpen, pFile, NULL);
+}
+
+
+RTDECL(int)  RTFileOpenEx(const char *pszFilename, uint64_t fOpen, PRTFILE phFile, PRTFILEACTION penmActionTaken)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phFile, VERR_INVALID_POINTER);
+    *phFile = NIL_RTFILE;
+    if (penmActionTaken)
+        *penmActionTaken = RTFILEACTION_INVALID;
+    AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
+
+    /*
+     * Merge forced open flags and validate them.
+     */
+    int rc = rtFileRecalcAndValidateFlags(&fOpen);
+    if (RT_FAILURE(rc))
+        return rc;
+#ifndef O_NONBLOCK
+    AssertReturn(!(fOpen & RTFILE_O_NON_BLOCK), VERR_INVALID_FLAGS);
+#endif
+#if defined(RT_OS_OS2) /* Cannot delete open files on OS/2. */
+    AssertReturn(!(fOpen & RTFILE_O_TEMP_AUTO_DELETE), VERR_NOT_SUPPORTED);
+#endif
+
+    /*
+     * Calculate open mode flags.
+     */
+    int fOpenMode = 0;
+#ifdef O_BINARY
+    fOpenMode |= O_BINARY;              /* (pc) */
+#endif
+#ifdef O_LARGEFILE
+    fOpenMode |= O_LARGEFILE;           /* (linux, solaris) */
+#endif
+#ifdef O_NOINHERIT
+    if (!(fOpen & RTFILE_O_INHERIT))
+        fOpenMode |= O_NOINHERIT;
+#endif
+#ifdef O_CLOEXEC
+    int fHave_O_CLOEXEC = g_fHave_O_CLOEXEC;
+    if (   !(fOpen & RTFILE_O_INHERIT)
+        && (   fHave_O_CLOEXEC > 0
+            || (   fHave_O_CLOEXEC == 0
+                && (fHave_O_CLOEXEC = rtFileOpenExDetectCloExecSupport()) > 0)))
+        fOpenMode |= O_CLOEXEC;
+#endif
+#ifdef O_NONBLOCK
+    if (fOpen & RTFILE_O_NON_BLOCK)
+        fOpenMode |= O_NONBLOCK;
+#endif
+#ifdef O_SYNC
+    if (fOpen & RTFILE_O_WRITE_THROUGH)
+        fOpenMode |= O_SYNC;
+#endif
+#if defined(O_DIRECT) && defined(RT_OS_LINUX)
+    /* O_DIRECT is mandatory to get async I/O working on Linux. */
+    if (fOpen & RTFILE_O_ASYNC_IO)
+        fOpenMode |= O_DIRECT;
+#endif
+#if defined(O_DIRECT) && (defined(RT_OS_LINUX) || defined(RT_OS_FREEBSD) || defined(RT_OS_NETBSD))
+    /* Disable the kernel cache. */
+    if (fOpen & RTFILE_O_NO_CACHE)
+        fOpenMode |= O_DIRECT;
+#endif
+
+    /* create/truncate file */
+    switch (fOpen & RTFILE_O_ACTION_MASK)
+    {
+        case RTFILE_O_OPEN:             break;
+        case RTFILE_O_OPEN_CREATE:      fOpenMode |= O_CREAT; break;
+        case RTFILE_O_CREATE:           fOpenMode |= O_CREAT | O_EXCL; break;
+        case RTFILE_O_CREATE_REPLACE:   fOpenMode |= O_CREAT | O_TRUNC; break; /** @todo replacing needs fixing, this is *not* a 1:1 mapping! */
+        default:
+            AssertMsgFailed(("fOpen=%#llx\n", fOpen));
+            fOpen = (fOpen & ~RTFILE_O_ACTION_MASK) | RTFILE_O_OPEN;
+            break;
+
+    }
+    if (   (fOpen & RTFILE_O_TRUNCATE)
+        && (fOpen & RTFILE_O_ACTION_MASK) != RTFILE_O_CREATE)
+        fOpenMode |= O_TRUNC;
+
+    switch (fOpen & RTFILE_O_ACCESS_MASK)
+    {
+        case RTFILE_O_READ:
+            fOpenMode |= O_RDONLY; /* RTFILE_O_APPEND is ignored. */
+            break;
+        case RTFILE_O_WRITE:
+            fOpenMode |= fOpen & RTFILE_O_APPEND ? O_APPEND | O_WRONLY : O_WRONLY;
+            break;
+        case RTFILE_O_READWRITE:
+            fOpenMode |= fOpen & RTFILE_O_APPEND ? O_APPEND | O_RDWR   : O_RDWR;
+            break;
+        default:
+            AssertMsgFailedReturn(("RTFileOpen received an invalid RW value, fOpen=%#llx\n", fOpen), VERR_INVALID_FLAGS);
+    }
+
+    /* File mode. */
+    int fMode = (fOpen & RTFILE_O_CREATE_MODE_MASK)
+              ? (fOpen & RTFILE_O_CREATE_MODE_MASK) >> RTFILE_O_CREATE_MODE_SHIFT
+              : RT_FILE_PERMISSION;
+
+    /** @todo sharing? */
+
+    /*
+     * Open/create the file.
+     */
+    char const *pszNativeFilename;
+    rc = rtPathToNative(&pszNativeFilename, pszFilename, NULL);
+    if (RT_FAILURE(rc))
+        return (rc);
+
+    int fh;
+    int iErr;
+    if (!penmActionTaken)
+    {
+        fh   = open(pszNativeFilename, fOpenMode, fMode);
+        iErr = errno;
+    }
+    else
+    {
+        /* We need to know exactly which action was taken by open, Windows &
+           OS/2 style.  Can be tedious and subject to races:  */
+        switch (fOpen & RTFILE_O_ACTION_MASK)
+        {
+            case RTFILE_O_OPEN:
+                Assert(!(fOpenMode & O_CREAT));
+                Assert(!(fOpenMode & O_EXCL));
+                fh   = open(pszNativeFilename, fOpenMode, fMode);
+                iErr = errno;
+                if (fh >= 0)
+                    *penmActionTaken = fOpenMode & O_TRUNC ? RTFILEACTION_TRUNCATED : RTFILEACTION_OPENED;
+                break;
+
+            case RTFILE_O_CREATE:
+                Assert(fOpenMode & O_CREAT);
+                Assert(fOpenMode & O_EXCL);
+                fh   = open(pszNativeFilename, fOpenMode, fMode);
+                iErr = errno;
+                if (fh >= 0)
+                    *penmActionTaken = RTFILEACTION_CREATED;
+                else if (iErr == EEXIST)
+                    *penmActionTaken = RTFILEACTION_ALREADY_EXISTS;
+                break;
+
+            case RTFILE_O_OPEN_CREATE:
+            case RTFILE_O_CREATE_REPLACE:
+            {
+                Assert(fOpenMode & O_CREAT);
+                Assert(!(fOpenMode & O_EXCL));
+                int iTries = 64;
+                while (iTries-- > 0)
+                {
+                    /* Yield the CPU if we've raced too long. */
+                    if (iTries < 4)
+                        RTThreadSleep(2 - (iTries & 1));
+
+                    /* Try exclusive creation first: */
+                    fh   = open(pszNativeFilename, fOpenMode | O_EXCL, fMode);
+                    iErr = errno;
+                    if (fh >= 0)
+                    {
+                        *penmActionTaken = RTFILEACTION_CREATED;
+                        break;
+                    }
+                    if (iErr != EEXIST)
+                        break;
+
+                    /* If the file exists, try open it: */
+                    fh   = open(pszNativeFilename, fOpenMode & ~O_CREAT, fMode);
+                    iErr = errno;
+                    if (fh >= 0)
+                    {
+                        if ((fOpen & RTFILE_O_ACTION_MASK) == RTFILE_O_OPEN_CREATE)
+                            *penmActionTaken = fOpenMode & O_TRUNC ? RTFILEACTION_TRUNCATED : RTFILEACTION_OPENED;
+                        else
+                            *penmActionTaken = RTFILEACTION_REPLACED;
+                        break;
+                    }
+                    if (iErr != ENOENT)
+                        break;
+                }
+                Assert(iTries >= 0);
+                if (iTries < 0)
+                {
+                    /* Thanks for the race, but we need to get on with things.  */
+                    fh   = open(pszNativeFilename, fOpenMode, fMode);
+                    iErr = errno;
+                    if (fh >= 0)
+                        *penmActionTaken = RTFILEACTION_OPENED;
+                }
+                break;
+            }
+
+            default:
+                AssertMsgFailed(("fOpen=%#llx fOpenMode=%#x\n", fOpen, fOpenMode));
+                iErr = EINVAL;
+                fh = -1;
+                break;
+        }
+    }
+
+    rtPathFreeNative(pszNativeFilename, pszFilename);
+    if (fh >= 0)
+    {
+        iErr = 0;
+
+        /*
+         * If temporary file, delete it.
+         */
+        if (fOpen & RTFILE_O_TEMP_AUTO_DELETE)
+        {
+            /** @todo Use funlinkat/funlink or similar here when available!  Or better,
+             *        use O_TMPFILE, only that may require fallback as not supported by
+             *        all file system on linux. */
+            iErr = unlink(pszNativeFilename);
+            Assert(iErr == 0);
+        }
+
+        /*
+         * Mark the file handle close on exec, unless inherit is specified.
+         */
+        if (    !(fOpen & RTFILE_O_INHERIT)
+#ifdef O_NOINHERIT
+            &&  !(fOpenMode & O_NOINHERIT)  /* Take care since it might be a zero value dummy. */
+#endif
+#ifdef O_CLOEXEC
+            &&  fHave_O_CLOEXEC <= 0
+#endif
+            )
+            iErr = fcntl(fh, F_SETFD, FD_CLOEXEC) >= 0 ? 0 : errno;
+
+        /*
+         * Switch direct I/O on now if requested and required.
+         */
+#if defined(RT_OS_DARWIN) \
+ || (defined(RT_OS_SOLARIS) && !defined(IN_GUEST))
+        if (iErr == 0 && (fOpen & RTFILE_O_NO_CACHE))
+        {
+# if defined(RT_OS_DARWIN)
+            iErr = fcntl(fh, F_NOCACHE, 1)        >= 0 ? 0 : errno;
+# else
+            iErr = directio(fh, DIRECTIO_ON)      >= 0 ? 0 : errno;
+# endif
+        }
+#endif
+
+        /*
+         * Implement / emulate file sharing.
+         *
+         * We need another mode which allows skipping this stuff completely
+         * and do things the UNIX way. So for the present this is just a debug
+         * aid that can be enabled by developers too lazy to test on Windows.
+         */
+#if 0 && defined(RT_OS_LINUX)
+        if (iErr == 0)
+        {
+            /* This approach doesn't work because only knfsd checks for these
+               buggers. :-( */
+            int iLockOp;
+            switch (fOpen & RTFILE_O_DENY_MASK)
+            {
+                default:
+                AssertFailed();
+                case RTFILE_O_DENY_NONE:
+                case RTFILE_O_DENY_NOT_DELETE:
+                    iLockOp = LOCK_MAND | LOCK_READ | LOCK_WRITE;
+                    break;
+                case RTFILE_O_DENY_READ:
+                case RTFILE_O_DENY_READ | RTFILE_O_DENY_NOT_DELETE:
+                    iLockOp = LOCK_MAND | LOCK_WRITE;
+                    break;
+                case RTFILE_O_DENY_WRITE:
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_NOT_DELETE:
+                    iLockOp = LOCK_MAND | LOCK_READ;
+                    break;
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ:
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ | RTFILE_O_DENY_NOT_DELETE:
+                    iLockOp = LOCK_MAND;
+                    break;
+            }
+            iErr = flock(fh, iLockOp | LOCK_NB);
+            if (iErr != 0)
+                iErr = errno == EAGAIN ? ETXTBSY : 0;
+        }
+#endif /* 0 && RT_OS_LINUX */
+#if defined(DEBUG_bird) && !defined(RT_OS_SOLARIS)
+        if (iErr == 0)
+        {
+            /* This emulation is incomplete but useful. */
+            switch (fOpen & RTFILE_O_DENY_MASK)
+            {
+                default:
+                AssertFailed();
+                case RTFILE_O_DENY_NONE:
+                case RTFILE_O_DENY_NOT_DELETE:
+                case RTFILE_O_DENY_READ:
+                case RTFILE_O_DENY_READ | RTFILE_O_DENY_NOT_DELETE:
+                    break;
+                case RTFILE_O_DENY_WRITE:
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_NOT_DELETE:
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ:
+                case RTFILE_O_DENY_WRITE | RTFILE_O_DENY_READ | RTFILE_O_DENY_NOT_DELETE:
+                    if (fOpen & RTFILE_O_WRITE)
+                    {
+                        iErr = flock(fh, LOCK_EX | LOCK_NB);
+                        if (iErr != 0)
+                            iErr = errno == EAGAIN ? ETXTBSY : 0;
+                    }
+                    break;
+            }
+        }
+#endif
+#ifdef RT_OS_SOLARIS
+        /** @todo Use fshare_t and associates, it's a perfect match. see sys/fcntl.h */
+#endif
+
+        /*
+         * We're done.
+         */
+        if (iErr == 0)
+        {
+            *phFile = (RTFILE)(uintptr_t)fh;
+            Assert((intptr_t)*phFile == fh);
+            LogFlow(("RTFileOpen(%p:{%RTfile}, %p:{%s}, %#llx): returns %Rrc\n",
+                     phFile, *phFile, pszFilename, pszFilename, fOpen, rc));
+            return VINF_SUCCESS;
+        }
+
+        close(fh);
+    }
+    return RTErrConvertFromErrno(iErr);
+}
+
+
+RTR3DECL(int)  RTFileOpenBitBucket(PRTFILE phFile, uint64_t fAccess)
+{
+    AssertReturn(   fAccess == RTFILE_O_READ
+                 || fAccess == RTFILE_O_WRITE
+                 || fAccess == RTFILE_O_READWRITE,
+                 VERR_INVALID_PARAMETER);
+    return RTFileOpen(phFile, "/dev/null", fAccess | RTFILE_O_DENY_NONE | RTFILE_O_OPEN);
+}
+
+
+RTR3DECL(int)  RTFileClose(RTFILE hFile)
+{
+    if (hFile == NIL_RTFILE)
+        return VINF_SUCCESS;
+    if (close(RTFileToNative(hFile)) == 0)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTFileFromNative(PRTFILE pFile, RTHCINTPTR uNative)
+{
+    AssertCompile(sizeof(uNative) == sizeof(*pFile));
+    if (uNative < 0)
+    {
+        AssertMsgFailed(("%p\n", uNative));
+        *pFile = NIL_RTFILE;
+        return VERR_INVALID_HANDLE;
+    }
+    *pFile = (RTFILE)uNative;
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(RTHCINTPTR) RTFileToNative(RTFILE hFile)
+{
+    AssertReturn(hFile != NIL_RTFILE, -1);
+    return (intptr_t)hFile;
+}
+
+
+RTFILE rtFileGetStandard(RTHANDLESTD enmStdHandle)
+{
+    int fd;
+    switch (enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:  fd = 0; break;
+        case RTHANDLESTD_OUTPUT: fd = 1; break;
+        case RTHANDLESTD_ERROR:  fd = 2; break;
+        default:
+            AssertFailedReturn(NIL_RTFILE);
+    }
+
+    struct stat st;
+    int rc = fstat(fd, &st);
+    if (rc == -1)
+        return NIL_RTFILE;
+    return (RTFILE)(intptr_t)fd;
+}
+
+
+RTR3DECL(int)  RTFileDelete(const char *pszFilename)
+{
+    char const *pszNativeFilename;
+    int rc = rtPathToNative(&pszNativeFilename, pszFilename, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (unlink(pszNativeFilename) != 0)
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeFilename, pszFilename);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int)  RTFileSeek(RTFILE hFile, int64_t offSeek, unsigned uMethod, uint64_t *poffActual)
+{
+    static const unsigned aSeekRecode[] =
+    {
+        SEEK_SET,
+        SEEK_CUR,
+        SEEK_END,
+    };
+
+    /*
+     * Validate input.
+     */
+    if (uMethod > RTFILE_SEEK_END)
+    {
+        AssertMsgFailed(("Invalid uMethod=%d\n", uMethod));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /* check that within off_t range. */
+    if (    sizeof(off_t) < sizeof(offSeek)
+        && (    (offSeek > 0 && (unsigned)(offSeek >> 32) != 0)
+            ||  (offSeek < 0 && (unsigned)(-offSeek >> 32) != 0)))
+    {
+        AssertMsgFailed(("64-bit search not supported\n"));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    off_t offCurrent = lseek(RTFileToNative(hFile), (off_t)offSeek, aSeekRecode[uMethod]);
+    if (offCurrent != ~0)
+    {
+        if (poffActual)
+            *poffActual = (uint64_t)offCurrent;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int)  RTFileRead(RTFILE hFile, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    if (cbToRead <= 0)
+    {
+        if (pcbRead)
+            *pcbRead = 0;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Attempt read.
+     */
+    ssize_t cbRead = read(RTFileToNative(hFile), pvBuf, cbToRead);
+    if (cbRead >= 0)
+    {
+        if (pcbRead)
+            /* caller can handle partial read. */
+            *pcbRead = cbRead;
+        else
+        {
+            /* Caller expects all to be read. */
+            while ((ssize_t)cbToRead > cbRead)
+            {
+                ssize_t cbReadPart = read(RTFileToNative(hFile), (char*)pvBuf + cbRead, cbToRead - cbRead);
+                if (cbReadPart <= 0)
+                {
+                    if (cbReadPart == 0)
+                        return VERR_EOF;
+                    return RTErrConvertFromErrno(errno);
+                }
+                cbRead += cbReadPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int)  RTFileWrite(RTFILE hFile, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    if (cbToWrite <= 0)
+        return VINF_SUCCESS;
+
+    /*
+     * Attempt write.
+     */
+    ssize_t cbWritten = write(RTFileToNative(hFile), pvBuf, cbToWrite);
+    if (cbWritten >= 0)
+    {
+        if (pcbWritten)
+            /* caller can handle partial write. */
+            *pcbWritten = cbWritten;
+        else
+        {
+            /* Caller expects all to be write. */
+            while ((ssize_t)cbToWrite > cbWritten)
+            {
+                ssize_t cbWrittenPart = write(RTFileToNative(hFile), (const char *)pvBuf + cbWritten, cbToWrite - cbWritten);
+                if (cbWrittenPart <= 0)
+                    return cbWrittenPart < 0 ? RTErrConvertFromErrno(errno) : VERR_TRY_AGAIN;
+                cbWritten += cbWrittenPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int)  RTFileSetSize(RTFILE hFile, uint64_t cbSize)
+{
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbSize)
+        &&  (cbSize >> 32) != 0)
+    {
+        AssertMsgFailed(("64-bit filesize not supported! cbSize=%lld\n", cbSize));
+        return VERR_NOT_SUPPORTED;
+    }
+
+#if defined(_MSC_VER) || (defined(RT_OS_OS2) && (!defined(__INNOTEK_LIBC__) || __INNOTEK_LIBC__ < 0x006))
+    if (chsize(RTFileToNative(hFile), (off_t)cbSize) == 0)
+#else
+    /* This relies on a non-standard feature of FreeBSD, Linux, and OS/2
+     * LIBC v0.6 and higher. (SuS doesn't define ftruncate() and size bigger
+     * than the file.)
+     */
+    if (ftruncate(RTFileToNative(hFile), (off_t)cbSize) == 0)
+#endif
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTFileQuerySize(RTFILE hFile, uint64_t *pcbSize)
+{
+    /*
+     * Ask fstat() first.
+     */
+    struct stat st;
+    if (!fstat(RTFileToNative(hFile), &st))
+    {
+        *pcbSize = st.st_size;
+        if (   st.st_size != 0
+#if defined(RT_OS_SOLARIS) || defined(RT_OS_DARWIN)
+            || (!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode))
+#elif defined(RT_OS_FREEBSD) || defined(RT_OS_NETBSD) || defined(RT_OS_DARWIN)
+            || !S_ISCHR(st.st_mode)
+#else
+            || !S_ISBLK(st.st_mode)
+#endif
+            )
+            return VINF_SUCCESS;
+
+        /*
+         * It could be a block device.  Try determin the size by I/O control
+         * query or seek.
+         */
+#ifdef RT_OS_DARWIN
+        uint64_t cBlocks;
+        if (!ioctl(RTFileToNative(hFile), DKIOCGETBLOCKCOUNT, &cBlocks))
+        {
+            uint32_t cbBlock;
+            if (!ioctl(RTFileToNative(hFile), DKIOCGETBLOCKSIZE, &cbBlock))
+            {
+                *pcbSize = cBlocks * cbBlock;
+                return VINF_SUCCESS;
+            }
+        }
+
+        /* Always fail block devices.  Character devices doesn't all need to be
+           /dev/rdisk* nodes, they should return ENOTTY but /dev/null returns ENODEV
+           and we include EINVAL just in case. */
+        if (!S_ISBLK(st.st_mode) && (errno == ENOTTY || errno == ENODEV || errno == EINVAL))
+            return VINF_SUCCESS;
+
+#elif defined(RT_OS_SOLARIS)
+        struct dk_minfo MediaInfo;
+        if (!ioctl(RTFileToNative(hFile), DKIOCGMEDIAINFO, &MediaInfo))
+        {
+            *pcbSize = MediaInfo.dki_capacity * MediaInfo.dki_lbsize;
+            return VINF_SUCCESS;
+        }
+        /* might not be a block device. */
+        if (errno == EINVAL || errno == ENOTTY)
+            return VINF_SUCCESS;
+
+#elif defined(RT_OS_FREEBSD)
+        off_t cbMedia = 0;
+        if (!ioctl(RTFileToNative(hFile), DIOCGMEDIASIZE, &cbMedia))
+        {
+            *pcbSize = cbMedia;
+            return VINF_SUCCESS;
+        }
+        /* might not be a block device. */
+        if (errno == EINVAL || errno == ENOTTY)
+            return VINF_SUCCESS;
+
+#else
+        /* PORTME! Avoid this path when possible. */
+        uint64_t offSaved = UINT64_MAX;
+        int rc = RTFileSeek(hFile, 0, RTFILE_SEEK_CURRENT, &offSaved);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTFileSeek(hFile, 0, RTFILE_SEEK_END, pcbSize);
+            int rc2 = RTFileSeek(hFile, offSaved, RTFILE_SEEK_BEGIN, NULL);
+            if (RT_SUCCESS(rc))
+                return rc2;
+        }
+#endif
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTFileQueryMaxSizeEx(RTFILE hFile, PRTFOFF pcbMax)
+{
+    /*
+     * Save the current location
+     */
+    uint64_t offOld = UINT64_MAX;
+    int rc = RTFileSeek(hFile, 0, RTFILE_SEEK_CURRENT, &offOld);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    uint64_t offLow  =       0;
+    uint64_t offHigh = INT64_MAX; /* we don't need bigger files */
+    /** @todo Unfortunately this does not work for certain file system types,
+     * for instance cifs mounts. Even worse, statvfs.f_fsid returns 0 for such
+     * file systems. */
+
+    /*
+     * Quickly guess the order of magnitude for offHigh and offLow.
+     */
+    {
+        uint64_t offHighPrev = offHigh;
+        while (offHigh >= INT32_MAX)
+        {
+            rc = RTFileSeek(hFile, offHigh, RTFILE_SEEK_BEGIN, NULL);
+            if (RT_SUCCESS(rc))
+            {
+                offLow = offHigh;
+                offHigh = offHighPrev;
+                break;
+            }
+            else
+            {
+                offHighPrev = offHigh;
+                offHigh >>= 8;
+            }
+        }
+    }
+
+    /*
+     * Sanity: if the seek to the initial offHigh (INT64_MAX) works, then
+     * this algorithm cannot possibly work. Declare defeat.
+     */
+    if (offLow == offHigh)
+    {
+        rc = RTFileSeek(hFile, offOld, RTFILE_SEEK_BEGIN, NULL);
+        if (RT_SUCCESS(rc))
+            rc = VERR_NOT_IMPLEMENTED;
+
+        return rc;
+    }
+
+    /*
+     * Perform a binary search for the max file size.
+     */
+    while (offLow <= offHigh)
+    {
+        uint64_t offMid = offLow + (offHigh - offLow) / 2;
+        rc = RTFileSeek(hFile, offMid, RTFILE_SEEK_BEGIN, NULL);
+        if (RT_FAILURE(rc))
+            offHigh = offMid - 1;
+        else
+            offLow  = offMid + 1;
+    }
+
+    if (pcbMax)
+        *pcbMax = RT_MIN(offLow, offHigh);
+    return RTFileSeek(hFile, offOld, RTFILE_SEEK_BEGIN, NULL);
+}
+
+
+RTR3DECL(bool) RTFileIsValid(RTFILE hFile)
+{
+    if (hFile != NIL_RTFILE)
+    {
+        int fFlags = fcntl(RTFileToNative(hFile), F_GETFD);
+        if (fFlags >= 0)
+            return true;
+    }
+    return false;
+}
+
+
+RTR3DECL(int) RTFileFlush(RTFILE hFile)
+{
+    if (!fsync(RTFileToNative(hFile)))
+        return VINF_SUCCESS;
+    /* Ignore EINVAL here as that's what returned for pseudo ttys
+       and other odd handles. */
+    if (errno == EINVAL)
+        return VINF_NOT_SUPPORTED;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTFileIoCtl(RTFILE hFile, unsigned long ulRequest, void *pvData, unsigned cbData, int *piRet)
+{
+    NOREF(cbData);
+    int rc = ioctl(RTFileToNative(hFile), ulRequest, pvData);
+    if (piRet)
+        *piRet = rc;
+    return rc >= 0 ? VINF_SUCCESS : RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTFileSetMode(RTFILE hFile, RTFMODE fMode)
+{
+    /*
+     * Normalize the mode and call the API.
+     */
+    fMode = rtFsModeNormalize(fMode, NULL, 0, RTFS_TYPE_FILE);
+    if (!rtFsModeIsValid(fMode))
+        return VERR_INVALID_PARAMETER;
+
+    if (fchmod(RTFileToNative(hFile), fMode & RTFS_UNIX_MASK))
+    {
+        int rc = RTErrConvertFromErrno(errno);
+        Log(("RTFileSetMode(%RTfile,%RTfmode): returns %Rrc\n", hFile, fMode, rc));
+        return rc;
+    }
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFileSetOwner(RTFILE hFile, uint32_t uid, uint32_t gid)
+{
+    uid_t uidNative = uid != NIL_RTUID ? (uid_t)uid : (uid_t)-1;
+    AssertReturn(uid == uidNative, VERR_INVALID_PARAMETER);
+    gid_t gidNative = gid != NIL_RTGID ? (gid_t)gid : (gid_t)-1;
+    AssertReturn(gid == gidNative, VERR_INVALID_PARAMETER);
+
+    if (fchown(RTFileToNative(hFile), uidNative, gidNative))
+        return RTErrConvertFromErrno(errno);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTFileRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(*pszSrc, ("%p\n", pszSrc), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(*pszDst, ("%p\n", pszDst), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Take common cause with RTPathRename.
+     */
+    int rc = rtPathPosixRename(pszSrc, pszDst, fRename, RTFS_TYPE_FILE);
+
+    LogFlow(("RTDirRename(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n",
+             pszSrc, pszSrc, pszDst, pszDst, fRename, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fileio-sg-at-posix.cpp b/src/VBox/Runtime/r3/posix/fileio-sg-at-posix.cpp
new file mode 100644
index 00000000..5fdea41a
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileio-sg-at-posix.cpp
@@ -0,0 +1,298 @@
+/* $Id: fileio-sg-at-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, RTFileSgReadAt & RTFileSgWriteAt, posixy.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+/*
+ * Determin whether we've got preadv and pwritev.
+ */
+#include <iprt/cdefs.h>
+#ifdef RT_OS_LINUX
+/* Linux has these since glibc 2.10 and Linux 2.6.30: */
+# include <features.h>
+# ifdef __GLIBC_PREREQ
+#  if __GLIBC_PREREQ(2,10)
+#   define HAVE_PREADV_AND_PWRITEV 1
+#else
+#  endif
+# endif
+
+#elif defined(RT_OS_FREEBSD)
+/* FreeBSD has these since 6.0: */
+# include <osreldate.h>
+# ifdef __FreeBSD_version
+#  if __FreeBSD_version >= 600000
+#   define HAVE_PREADV_AND_PWRITEV 1
+#  endif
+# endif
+
+#endif
+
+#ifndef HAVE_PREADV_AND_PWRITEV
+
+# include "../../generic/fileio-sg-at-generic.cpp"
+
+#else /* HAVE_PREADV_AND_PWRITEV - rest of the file */
+
+# include <errno.h>
+# include <sys/types.h>
+# include <sys/uio.h>
+# include <unistd.h>
+# include <limits.h>
+# if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD) || defined(RT_OS_NETBSD) || defined(RT_OS_OPENBSD)
+#  include <sys/syslimits.h>
+# endif
+
+# include "internal/iprt.h"
+# include <iprt/file.h>
+
+# include <iprt/assert.h>
+# include <iprt/err.h>
+# include <iprt/log.h>
+
+# ifndef UIO_MAXIOV
+#  ifdef IOV_MAX
+#   define UIO_MAXIOV IOV_MAX
+#  else
+#   error "UIO_MAXIOV and IOV_MAX are undefined"
+#  endif
+# endif
+
+
+/* These assumptions simplifies things a lot here. */
+AssertCompileMembersSameSizeAndOffset(struct iovec, iov_base, RTSGSEG, pvSeg);
+AssertCompileMembersSameSizeAndOffset(struct iovec, iov_len,  RTSGSEG, cbSeg);
+
+
+RTDECL(int)  RTFileSgReadAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead)
+{
+    /*
+     * Make sure we set pcbRead.
+     */
+    if (pcbRead)
+        *pcbRead = 0;
+
+    /*
+     * Special case: Zero read == seek.
+     */
+    if (cbToRead == 0)
+        return RTFileSeek(hFile, off, RTFILE_SEEK_BEGIN, NULL);
+
+    /*
+     * We can use the segment array directly if we're at the start of the
+     * current S/G segment and cbToRead matches the remainder exactly.
+     */
+    size_t cbTotalRead = 0;
+
+    size_t const cbSgBufLeft = RTSgBufCalcLengthLeft(pSgBuf);
+    AssertMsgReturn(cbSgBufLeft >= cbToRead, ("%#zx vs %#zx\n", cbSgBufLeft, cbToRead), VERR_INVALID_PARAMETER);
+
+    if (cbToRead == cbSgBufLeft)
+        while (RTSgBufIsAtStartOfSegment(pSgBuf))
+        {
+            size_t const cSegsLeft  = pSgBuf->cSegs - pSgBuf->idxSeg;
+            ssize_t      cbThisRead = preadv(RTFileToNative(hFile), (const struct iovec *)&pSgBuf->paSegs[pSgBuf->idxSeg],
+                                             RT_MIN(cSegsLeft, UIO_MAXIOV), off);
+            if (cbThisRead >= 0)
+            {
+                AssertStmt((size_t)cbThisRead <= cbToRead, cbThisRead = cbToRead);
+
+                RTSgBufAdvance(pSgBuf, cbThisRead);
+                cbTotalRead += cbThisRead;
+                cbToRead    -= cbThisRead;
+                if (cbToRead == 0)
+                {
+                    if (pcbRead)
+                        *pcbRead = cbTotalRead;
+                    return VINF_SUCCESS;
+                }
+
+                if (   pcbRead
+                    && (   cSegsLeft <= UIO_MAXIOV
+                        || cbThisRead == 0 /* typically EOF */ ))
+                {
+                    *pcbRead = cbTotalRead;
+                    return VINF_SUCCESS;
+                }
+                if (cbThisRead == 0)
+                    return VERR_EOF;
+
+                off += cbThisRead;
+            }
+            else if (cbTotalRead > 0 && pcbRead)
+            {
+                *pcbRead = cbTotalRead;
+                return VINF_SUCCESS;
+            }
+            else
+                return RTErrConvertFromErrno(errno);
+        }
+
+    /*
+     * Unaligned start or not reading the whole buffer.  For reasons of
+     * simplicity, we work the input segment by segment like the generic code.
+     */
+    int rc = VINF_SUCCESS;
+    while (cbToRead > 0)
+    {
+        size_t cbSeg;
+        void  *pvSeg = RTSgBufGetCurrentSegment(pSgBuf, cbToRead, &cbSeg);
+        size_t cbThisRead = cbSeg;
+        rc = RTFileReadAt(hFile, off, pvSeg, cbSeg, pcbRead ? &cbThisRead : NULL);
+        if (RT_SUCCESS(rc))
+        {
+            RTSgBufAdvance(pSgBuf, cbThisRead);
+            cbTotalRead += cbThisRead;
+        }
+        else
+            break;
+        if ((size_t)cbThisRead < cbSeg)
+        {
+            AssertStmt(pcbRead, rc = VERR_INTERNAL_ERROR_2);
+            break;
+        }
+
+        Assert(cbSeg == cbThisRead);
+        cbToRead -= cbSeg;
+        off      += cbSeg;
+    }
+    if (pcbRead)
+        *pcbRead = cbTotalRead;
+    return rc;
+}
+
+
+RTDECL(int)  RTFileSgWriteAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    /*
+     * Make sure we set pcbWritten.
+     */
+    if (pcbWritten)
+        *pcbWritten = 0;
+
+    /*
+     * Special case: Zero write == seek.
+     */
+    if (cbToWrite == 0)
+        return RTFileSeek(hFile, off, RTFILE_SEEK_BEGIN, NULL);
+
+    /*
+     * We can use the segment array directly if we're at the start of the
+     * current S/G segment and cbToWrite matches the remainder exactly.
+     */
+    size_t cbTotalWritten = 0;
+
+    size_t const cbSgBufLeft = RTSgBufCalcLengthLeft(pSgBuf);
+    AssertMsgReturn(cbSgBufLeft >= cbToWrite, ("%#zx vs %#zx\n", cbSgBufLeft, cbToWrite), VERR_INVALID_PARAMETER);
+
+    if (cbToWrite == cbSgBufLeft)
+        while (RTSgBufIsAtStartOfSegment(pSgBuf))
+        {
+            size_t const cSegsLeft     = pSgBuf->cSegs - pSgBuf->idxSeg;
+            ssize_t      cbThisWritten = pwritev(RTFileToNative(hFile), (const struct iovec *)&pSgBuf->paSegs[pSgBuf->idxSeg],
+                                                 RT_MIN(cSegsLeft, UIO_MAXIOV), off);
+            if (cbThisWritten >= 0)
+            {
+                AssertStmt((size_t)cbThisWritten <= cbToWrite, cbThisWritten = cbToWrite);
+
+                RTSgBufAdvance(pSgBuf, cbThisWritten);
+                cbTotalWritten += cbThisWritten;
+                cbToWrite      -= cbThisWritten;
+                if (cbToWrite == 0)
+                {
+                    if (pcbWritten)
+                        *pcbWritten = cbTotalWritten;
+                    return VINF_SUCCESS;
+                }
+
+                if (   pcbWritten
+                    && (   cSegsLeft <= UIO_MAXIOV
+                        || cbThisWritten == 0 /* non-file, full buffer/whatever */ ))
+                {
+                    *pcbWritten = cbTotalWritten;
+                    return VINF_SUCCESS;
+                }
+                if (cbThisWritten == 0)
+                    return VERR_TRY_AGAIN;
+
+                off += cbThisWritten;
+            }
+            else if (cbTotalWritten > 0 && pcbWritten)
+            {
+                *pcbWritten = cbTotalWritten;
+                return VINF_SUCCESS;
+            }
+            else
+                return RTErrConvertFromErrno(errno);
+        }
+
+    /*
+     * Unaligned start or not writing the whole buffer.  For reasons of
+     * simplicity, we work the input segment by segment like the generic code.
+     */
+    int rc = VINF_SUCCESS;
+    while (cbToWrite > 0)
+    {
+        size_t cbSeg;
+        void  *pvSeg = RTSgBufGetCurrentSegment(pSgBuf, cbToWrite, &cbSeg);
+        size_t cbThisWritten = cbSeg;
+        rc = RTFileWriteAt(hFile, off, pvSeg, cbSeg, pcbWritten ? &cbThisWritten : NULL);
+        if (RT_SUCCESS(rc))
+        {
+            RTSgBufAdvance(pSgBuf, cbThisWritten);
+            cbTotalWritten += cbThisWritten;
+        }
+        else
+            break;
+        if ((size_t)cbThisWritten < cbSeg)
+        {
+            AssertStmt(pcbWritten, rc = VERR_INTERNAL_ERROR_2);
+            break;
+        }
+
+        Assert(cbSeg == cbThisWritten);
+        cbToWrite -= cbSeg;
+        off       += cbSeg;
+    }
+    if (pcbWritten)
+        *pcbWritten = cbTotalWritten;
+    return rc;
+}
+
+#endif /* HAVE_PREADV_AND_PWRITEV */
+
diff --git a/src/VBox/Runtime/r3/posix/fileio-sg-posix.cpp b/src/VBox/Runtime/r3/posix/fileio-sg-posix.cpp
new file mode 100644
index 00000000..c8c95786
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileio-sg-posix.cpp
@@ -0,0 +1,260 @@
+/* $Id: fileio-sg-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, RTFileSgRead & RTFileSgWrite, posixy.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cdefs.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <limits.h>
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD) || defined(RT_OS_NETBSD) || defined(RT_OS_OPENBSD)
+# include <sys/syslimits.h>
+#endif
+
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+
+#ifndef UIO_MAXIOV
+# ifdef IOV_MAX
+#  define UIO_MAXIOV IOV_MAX
+# else
+#  error "UIO_MAXIOV and IOV_MAX are undefined"
+# endif
+#endif
+
+
+/* These assumptions simplifies things a lot here. */
+AssertCompileMembersSameSizeAndOffset(struct iovec, iov_base, RTSGSEG, pvSeg);
+AssertCompileMembersSameSizeAndOffset(struct iovec, iov_len,  RTSGSEG, cbSeg);
+
+
+RTDECL(int)  RTFileSgRead(RTFILE hFile, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead)
+{
+    /*
+     * Make sure we set pcbRead.
+     */
+    if (pcbRead)
+        *pcbRead = 0;
+
+    /*
+     * Special case: Zero read == nop.
+     */
+    if (cbToRead == 0)
+        return VINF_SUCCESS;
+
+    /*
+     * We can use the segment array directly if we're at the start of the
+     * current S/G segment and cbToRead matches the remainder exactly.
+     */
+    size_t cbTotalRead = 0;
+
+    size_t const cbSgBufLeft = RTSgBufCalcLengthLeft(pSgBuf);
+    AssertMsgReturn(cbSgBufLeft >= cbToRead, ("%#zx vs %#zx\n", cbSgBufLeft, cbToRead), VERR_INVALID_PARAMETER);
+
+    if (cbToRead == cbSgBufLeft)
+        while (RTSgBufIsAtStartOfSegment(pSgBuf))
+        {
+            size_t const cSegsLeft  = pSgBuf->cSegs - pSgBuf->idxSeg;
+            ssize_t      cbThisRead = readv(RTFileToNative(hFile), (const struct iovec *)&pSgBuf->paSegs[pSgBuf->idxSeg],
+                                            RT_MIN(cSegsLeft, UIO_MAXIOV));
+            if (cbThisRead >= 0)
+            {
+                AssertStmt((size_t)cbThisRead <= cbToRead, cbThisRead = cbToRead);
+
+                RTSgBufAdvance(pSgBuf, cbThisRead);
+                cbTotalRead += cbThisRead;
+                cbToRead    -= cbThisRead;
+                if (cbToRead == 0)
+                {
+                    if (pcbRead)
+                        *pcbRead = cbTotalRead;
+                    return VINF_SUCCESS;
+                }
+
+                if (   pcbRead
+                    && (   cSegsLeft <= UIO_MAXIOV
+                        || cbThisRead == 0 /* typically EOF */ ))
+                {
+                    *pcbRead = cbTotalRead;
+                    return VINF_SUCCESS;
+                }
+                if (cbThisRead == 0)
+                    return VERR_EOF;
+            }
+            else if (cbTotalRead > 0 && pcbRead)
+            {
+                *pcbRead = cbTotalRead;
+                return VINF_SUCCESS;
+            }
+            else
+                return RTErrConvertFromErrno(errno);
+        }
+
+    /*
+     * Unaligned start or not reading the whole buffer.  For reasons of
+     * simplicity, we work the input segment by segment like the generic code.
+     */
+    int rc = VINF_SUCCESS;
+    while (cbToRead > 0)
+    {
+        size_t cbSeg;
+        void  *pvSeg = RTSgBufGetCurrentSegment(pSgBuf, cbToRead, &cbSeg);
+        size_t cbThisRead = cbSeg;
+        rc = RTFileRead(hFile, pvSeg, cbSeg, pcbRead ? &cbThisRead : NULL);
+        if (RT_SUCCESS(rc))
+        {
+            RTSgBufAdvance(pSgBuf, cbThisRead);
+            cbTotalRead += cbThisRead;
+        }
+        else
+            break;
+        if ((size_t)cbThisRead < cbSeg)
+        {
+            AssertStmt(pcbRead, rc = VERR_INTERNAL_ERROR_2);
+            break;
+        }
+
+        Assert(cbSeg == cbThisRead);
+        cbToRead -= cbSeg;
+    }
+    if (pcbRead)
+        *pcbRead = cbTotalRead;
+    return rc;
+}
+
+
+RTDECL(int)  RTFileSgWrite(RTFILE hFile, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    /*
+     * Make sure we set pcbWritten.
+     */
+    if (pcbWritten)
+        *pcbWritten = 0;
+
+    /*
+     * Special case: Zero write == nop.
+     */
+    if (cbToWrite == 0)
+        return VINF_SUCCESS;
+
+    /*
+     * We can use the segment array directly if we're at the start of the
+     * current S/G segment and cbToWrite matches the remainder exactly.
+     */
+    size_t cbTotalWritten = 0;
+
+    size_t const cbSgBufLeft = RTSgBufCalcLengthLeft(pSgBuf);
+    AssertMsgReturn(cbSgBufLeft >= cbToWrite, ("%#zx vs %#zx\n", cbSgBufLeft, cbToWrite), VERR_INVALID_PARAMETER);
+
+    if (cbToWrite == cbSgBufLeft)
+        while (RTSgBufIsAtStartOfSegment(pSgBuf))
+        {
+            size_t const cSegsLeft     = pSgBuf->cSegs - pSgBuf->idxSeg;
+            ssize_t      cbThisWritten = writev(RTFileToNative(hFile), (const struct iovec *)&pSgBuf->paSegs[pSgBuf->idxSeg],
+                                                RT_MIN(cSegsLeft, UIO_MAXIOV));
+            if (cbThisWritten >= 0)
+            {
+                AssertStmt((size_t)cbThisWritten <= cbToWrite, cbThisWritten = cbToWrite);
+
+                RTSgBufAdvance(pSgBuf, cbThisWritten);
+                cbTotalWritten += cbThisWritten;
+                cbToWrite      -= cbThisWritten;
+                if (cbToWrite == 0)
+                {
+                    if (pcbWritten)
+                        *pcbWritten = cbTotalWritten;
+                    return VINF_SUCCESS;
+                }
+
+                if (   pcbWritten
+                    && (   cSegsLeft <= UIO_MAXIOV
+                        || cbThisWritten == 0 /* non-file, full buffer/whatever */ ))
+                {
+                    *pcbWritten = cbTotalWritten;
+                    return VINF_SUCCESS;
+                }
+                if (cbThisWritten == 0)
+                    return VERR_TRY_AGAIN;
+            }
+            else if (cbTotalWritten > 0 && pcbWritten)
+            {
+                *pcbWritten = cbTotalWritten;
+                return VINF_SUCCESS;
+            }
+            else
+                return RTErrConvertFromErrno(errno);
+        }
+
+    /*
+     * Unaligned start or not writing the whole buffer.  For reasons of
+     * simplicity, we work the input segment by segment like the generic code.
+     */
+    int rc = VINF_SUCCESS;
+    while (cbToWrite > 0)
+    {
+        size_t cbSeg;
+        void  *pvSeg = RTSgBufGetCurrentSegment(pSgBuf, cbToWrite, &cbSeg);
+        size_t cbThisWritten = cbSeg;
+        rc = RTFileWrite(hFile, pvSeg, cbSeg, pcbWritten ? &cbThisWritten : NULL);
+        if (RT_SUCCESS(rc))
+        {
+            RTSgBufAdvance(pSgBuf, cbThisWritten);
+            cbTotalWritten += cbThisWritten;
+        }
+        else
+            break;
+        if ((size_t)cbThisWritten < cbSeg)
+        {
+            AssertStmt(pcbWritten, rc = VERR_INTERNAL_ERROR_2);
+            break;
+        }
+
+        Assert(cbSeg == cbThisWritten);
+        cbToWrite -= cbSeg;
+    }
+    if (pcbWritten)
+        *pcbWritten = cbTotalWritten;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fileio2-posix.cpp b/src/VBox/Runtime/r3/posix/fileio2-posix.cpp
new file mode 100644
index 00000000..4879f51e
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fileio2-posix.cpp
@@ -0,0 +1,210 @@
+/* $Id: fileio2-posix.cpp $ */
+/** @file
+ * IPRT - File I/O, POSIX, Part 2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#ifdef _MSC_VER
+# include <io.h>
+# include <stdio.h>
+#else
+# include <unistd.h>
+# include <sys/time.h>
+#endif
+#ifdef RT_OS_LINUX
+# include <sys/file.h>
+#endif
+#if defined(RT_OS_OS2) && (!defined(__INNOTEK_LIBC__) || __INNOTEK_LIBC__ < 0x006)
+# include <io.h>
+#endif
+
+#ifdef RT_OS_SOLARIS
+# define futimes(filedes, timeval)   futimesat(filedes, NULL, timeval)
+#endif
+
+#ifdef RT_OS_HAIKU
+# define USE_FUTIMENS
+#endif
+
+#include <iprt/file.h>
+#include <iprt/path.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+
+RTR3DECL(int) RTFileQueryInfo(RTFILE hFile, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pObjInfo, VERR_INVALID_PARAMETER);
+    if (    enmAdditionalAttribs < RTFSOBJATTRADD_NOTHING
+        ||  enmAdditionalAttribs > RTFSOBJATTRADD_LAST)
+    {
+        AssertMsgFailed(("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Query file info.
+     */
+    struct stat Stat;
+    if (fstat(RTFileToNative(hFile), &Stat))
+    {
+        int rc = RTErrConvertFromErrno(errno);
+        Log(("RTFileQueryInfo(%RTfile,,%d): returns %Rrc\n", hFile, enmAdditionalAttribs, rc));
+        return rc;
+    }
+
+    /*
+     * Setup the returned data.
+     */
+    rtFsConvertStatToObjInfo(pObjInfo, &Stat, NULL, 0);
+
+    /*
+     * Requested attributes (we cannot provide anything actually).
+     */
+    switch (enmAdditionalAttribs)
+    {
+        case RTFSOBJATTRADD_NOTHING:
+        case RTFSOBJATTRADD_UNIX:
+            /* done */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            rtFsObjInfoAttrSetUnixOwner(pObjInfo, Stat.st_uid);
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            rtFsObjInfoAttrSetUnixGroup(pObjInfo, Stat.st_gid);
+            break;
+
+        case RTFSOBJATTRADD_EASIZE:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+            pObjInfo->Attr.u.EASize.cb            = 0;
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    LogFlow(("RTFileQueryInfo(%RTfile,,%d): returns VINF_SUCCESS\n", hFile, enmAdditionalAttribs));
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTFileSetTimes(RTFILE hFile, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                             PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
+{
+    NOREF(pChangeTime); NOREF(pBirthTime);
+
+    /*
+     * We can only set AccessTime and ModificationTime, so if neither
+     * are specified we can return immediately.
+     */
+    if (!pAccessTime && !pModificationTime)
+        return VINF_SUCCESS;
+
+#ifdef USE_FUTIMENS
+    struct timespec aTimespecs[2];
+    if (pAccessTime && pModificationTime)
+    {
+        memcpy(&aTimespecs[0], pAccessTime, sizeof(struct timespec));
+        memcpy(&aTimespecs[1], pModificationTime, sizeof(struct timespec));
+    }
+    else
+    {
+        RTFSOBJINFO ObjInfo;
+        int rc = RTFileQueryInfo(hFile, &ObjInfo, RTFSOBJATTRADD_UNIX);
+        if (RT_FAILURE(rc))
+            return rc;
+        memcpy(&aTimespecs[0], pAccessTime ? pAccessTime : &ObjInfo.AccessTime, sizeof(struct timespec));
+        memcpy(&aTimespecs[1], pModificationTime ? pModificationTime : &ObjInfo.ModificationTime, sizeof(struct timespec));
+    }
+
+    if (futimens(RTFileToNative(hFile), aTimespecs))
+    {
+        int rc = RTErrConvertFromErrno(errno);
+        Log(("RTFileSetTimes(%RTfile,%p,%p,,): returns %Rrc\n", hFile, pAccessTime, pModificationTime, rc));
+        return rc;
+    }
+#else
+    /*
+     * Convert the input to timeval, getting the missing one if necessary,
+     * and call the API which does the change.
+     */
+    struct timeval aTimevals[2];
+    if (pAccessTime && pModificationTime)
+    {
+        RTTimeSpecGetTimeval(pAccessTime,       &aTimevals[0]);
+        RTTimeSpecGetTimeval(pModificationTime, &aTimevals[1]);
+    }
+    else
+    {
+        RTFSOBJINFO ObjInfo;
+        int rc = RTFileQueryInfo(hFile, &ObjInfo, RTFSOBJATTRADD_UNIX);
+        if (RT_FAILURE(rc))
+            return rc;
+        RTTimeSpecGetTimeval(pAccessTime        ? pAccessTime       : &ObjInfo.AccessTime,       &aTimevals[0]);
+        RTTimeSpecGetTimeval(pModificationTime  ? pModificationTime : &ObjInfo.ModificationTime, &aTimevals[1]);
+    }
+
+    /* XXX this falls back to utimes("/proc/self/fd/...",...) for older kernels/glibcs and this
+     * will not work for hardened builds where this directory is owned by root.root and mode 0500 */
+    if (futimes(RTFileToNative(hFile), aTimevals))
+    {
+        int rc = RTErrConvertFromErrno(errno);
+        Log(("RTFileSetTimes(%RTfile,%p,%p,,): returns %Rrc\n", hFile, pAccessTime, pModificationTime, rc));
+        return rc;
+    }
+#endif
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/filelock-posix.cpp b/src/VBox/Runtime/r3/posix/filelock-posix.cpp
new file mode 100644
index 00000000..3a0e230f
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/filelock-posix.cpp
@@ -0,0 +1,148 @@
+/* $Id: filelock-posix.cpp $ */
+/** @file
+ * IPRT - File Locking, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include <iprt/file.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+
+
+
+
+RTR3DECL(int)  RTFileLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    Assert(RTFILE_LOCK_WRITE);
+    fl.l_type   = (fLock & RTFILE_LOCK_WRITE) ? F_WRLCK : F_RDLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    Assert(RTFILE_LOCK_WAIT);
+    if (fcntl(RTFileToNative(hFile), (fLock & RTFILE_LOCK_WAIT) ? F_SETLKW : F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+
+    int iErr = errno;
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
+
+RTR3DECL(int)  RTFileChangeLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    /** @todo We never returns VERR_FILE_NOT_LOCKED for now. */
+    return RTFileLock(hFile, fLock, offLock, cbLock);
+}
+
+
+RTR3DECL(int)  RTFileUnlock(RTFILE hFile, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /*
+     * Validate offset.
+     */
+    if (    sizeof(off_t) < sizeof(cbLock)
+        &&  (    (offLock >> 32) != 0
+             ||  (cbLock >> 32) != 0
+             ||  ((offLock + cbLock) >> 32) != 0))
+    {
+        AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /* Prepare flock structure. */
+    struct flock fl;
+    fl.l_type   = F_UNLCK;
+    fl.l_whence = SEEK_SET;
+    fl.l_start  = (off_t)offLock;
+    fl.l_len    = (off_t)cbLock;
+    fl.l_pid    = 0;
+
+    if (fcntl(RTFileToNative(hFile), F_SETLK, &fl) >= 0)
+        return VINF_SUCCESS;
+
+    /** @todo check error codes for non existing lock. */
+    int iErr = errno;
+    if (    iErr == EAGAIN
+        ||  iErr == EACCES)
+        return VERR_FILE_LOCK_VIOLATION;
+
+    return RTErrConvertFromErrno(iErr);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fs-posix.cpp b/src/VBox/Runtime/r3/posix/fs-posix.cpp
new file mode 100644
index 00000000..04b3289a
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fs-posix.cpp
@@ -0,0 +1,346 @@
+/* $Id: fs-posix.cpp $ */
+/** @file
+ * IPRT - File System, Linux.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FS
+#include <sys/statvfs.h>
+#include <errno.h>
+#include <stdio.h>
+#ifdef RT_OS_LINUX
+# include <mntent.h>
+#endif
+#if defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+# include <sys/mount.h>
+#endif
+
+#include <iprt/fs.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/string.h>
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+
+RTR3DECL(int) RTFsQuerySizes(const char *pszFsPath, RTFOFF *pcbTotal, RTFOFF *pcbFree,
+                             uint32_t *pcbBlock, uint32_t *pcbSector)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the path and query the information.
+     */
+    char const *pszNativeFsPath;
+    int rc = rtPathToNative(&pszNativeFsPath, pszFsPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /** @todo I'm not quite sure if statvfs was properly specified by SuS, I have to check my own
+         * implementation and FreeBSD before this can eventually be promoted to posix. */
+        struct statvfs StatVFS;
+        RT_ZERO(StatVFS);
+        if (!statvfs(pszNativeFsPath, &StatVFS))
+        {
+            /*
+             * Calc the returned values.
+             */
+            if (pcbTotal)
+                *pcbTotal = (RTFOFF)StatVFS.f_blocks * StatVFS.f_frsize;
+            if (pcbFree)
+                *pcbFree = (RTFOFF)StatVFS.f_bavail * StatVFS.f_frsize;
+            if (pcbBlock)
+                *pcbBlock = StatVFS.f_frsize;
+            /* no idea how to get the sector... */
+            if (pcbSector)
+                *pcbSector = 512;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeFsPath, pszFsPath);
+    }
+
+    LogFlow(("RTFsQuerySizes(%p:{%s}, %p:{%RTfoff}, %p:{%RTfoff}, %p:{%RX32}, %p:{%RX32}): returns %Rrc\n",
+             pszFsPath, pszFsPath, pcbTotal, pcbTotal ? *pcbTotal : 0, pcbFree, pcbFree ? *pcbFree : 0,
+             pcbBlock, pcbBlock ? *pcbBlock : 0, pcbSector, pcbSector ? *pcbSector : 0, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTFsQuerySerial(const char *pszFsPath, uint32_t *pu32Serial)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pu32Serial, VERR_INVALID_POINTER);
+
+    /*
+     * Convert the path and query the stats.
+     * We're simply return the device id.
+     */
+    char const *pszNativeFsPath;
+    int rc = rtPathToNative(&pszNativeFsPath, pszFsPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat Stat;
+        if (!stat(pszNativeFsPath, &Stat))
+        {
+            if (pu32Serial)
+                *pu32Serial = (uint32_t)Stat.st_dev;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeFsPath, pszFsPath);
+    }
+    LogFlow(("RTFsQuerySerial(%p:{%s}, %p:{%RX32}: returns %Rrc\n",
+             pszFsPath, pszFsPath, pu32Serial, pu32Serial ? *pu32Serial : 0, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTFsQueryProperties(const char *pszFsPath, PRTFSPROPERTIES pProperties)
+{
+    /*
+     * Validate.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pProperties, VERR_INVALID_POINTER);
+
+    /*
+     * Convert the path and query the information.
+     */
+    char const *pszNativeFsPath;
+    int rc = rtPathToNative(&pszNativeFsPath, pszFsPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct statvfs StatVFS;
+        RT_ZERO(StatVFS);
+        if (!statvfs(pszNativeFsPath, &StatVFS))
+        {
+            /*
+             * Calc/fake the returned values.
+             */
+            pProperties->cbMaxComponent = StatVFS.f_namemax;
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+            pProperties->fCaseSensitive = false;
+#else
+            pProperties->fCaseSensitive = true;
+#endif
+            pProperties->fCompressed = false;
+            pProperties->fFileCompression = false;
+            pProperties->fReadOnly = !!(StatVFS.f_flag & ST_RDONLY);
+            pProperties->fRemote = false;
+            pProperties->fSupportsUnicode = true;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeFsPath, pszFsPath);
+    }
+
+    LogFlow(("RTFsQueryProperties(%p:{%s}, %p:{.cbMaxComponent=%u, .fReadOnly=%RTbool}): returns %Rrc\n",
+             pszFsPath, pszFsPath, pProperties, pProperties->cbMaxComponent, pProperties->fReadOnly, rc));
+    return rc;
+}
+
+
+RTR3DECL(bool) RTFsIsCaseSensitive(const char *pszFsPath)
+{
+    RT_NOREF_PV(pszFsPath);
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+    return false;
+#else
+    return true;
+#endif
+}
+
+
+RTR3DECL(int) RTFsQueryType(const char *pszFsPath, PRTFSTYPE penmType)
+{
+    *penmType = RTFSTYPE_UNKNOWN;
+
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the path and query the stats.
+     * We're simply return the device id.
+     */
+    char const *pszNativeFsPath;
+    int rc = rtPathToNative(&pszNativeFsPath, pszFsPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat Stat;
+        if (!stat(pszNativeFsPath, &Stat))
+        {
+#if defined(RT_OS_LINUX)
+            FILE *mounted = setmntent("/proc/mounts", "r");
+            if (!mounted)
+                mounted = setmntent("/etc/mtab", "r");
+            if (mounted)
+            {
+                char            szBuf[1024];
+                struct stat     mntStat;
+                struct mntent   mntEnt;
+                while (getmntent_r(mounted, &mntEnt, szBuf, sizeof(szBuf)))
+                {
+                    if (!stat(mntEnt.mnt_dir, &mntStat))
+                    {
+                        if (mntStat.st_dev == Stat.st_dev)
+                        {
+                            if (!strcmp("ext4", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_EXT4;
+                            else if (!strcmp("ext3", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_EXT3;
+                            else if (!strcmp("ext2", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_EXT2;
+                            else if (!strcmp("jfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_JFS;
+                            else if (!strcmp("xfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_XFS;
+                            else if (!strcmp("btrfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_BTRFS;
+                            else if (   !strcmp("vfat", mntEnt.mnt_type)
+                                     || !strcmp("msdos", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_FAT;
+                            else if (!strcmp("ntfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_NTFS;
+                            else if (!strcmp("hpfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_HPFS;
+                            else if (!strcmp("ufs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_UFS;
+                            else if (!strcmp("tmpfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_TMPFS;
+                            else if (!strcmp("hfsplus", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_HFS;
+                            else if (!strcmp("udf", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_UDF;
+                            else if (!strcmp("iso9660", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_ISO9660;
+                            else if (!strcmp("smbfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_SMBFS;
+                            else if (!strcmp("cifs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_CIFS;
+                            else if (!strcmp("nfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_NFS;
+                            else if (!strcmp("nfs4", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_NFS;
+                            else if (!strcmp("ocfs2", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_OCFS2;
+                            else if (!strcmp("sysfs", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_SYSFS;
+                            else if (!strcmp("proc", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_PROC;
+                            else if (   !strcmp("fuse", mntEnt.mnt_type)
+                                     || !strncmp("fuse.", mntEnt.mnt_type, 5)
+                                     || !strcmp("fuseblk", mntEnt.mnt_type))
+                                *penmType = RTFSTYPE_FUSE;
+                            else
+                            {
+                                /* sometimes there are more than one entry for the same partition */
+                                continue;
+                            }
+                            break;
+                        }
+                    }
+                }
+                endmntent(mounted);
+            }
+
+#elif defined(RT_OS_SOLARIS)
+            /*
+             * Home directories are normally loopback mounted in Solaris 11 (st_fstype=="lofs")
+             * so statvfs(2) is needed to get the underlying file system information.
+             */
+            struct statvfs statvfsBuf;
+            if (!statvfs(pszNativeFsPath, &statvfsBuf))
+            {
+                if (!strcmp("zfs", statvfsBuf.f_basetype))
+                    *penmType = RTFSTYPE_ZFS;
+                else if (!strcmp("ufs", statvfsBuf.f_basetype))
+                    *penmType = RTFSTYPE_UFS;
+                else if (!strcmp("nfs", statvfsBuf.f_basetype))
+                    *penmType = RTFSTYPE_NFS;
+            }
+
+#elif defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD)
+            struct statfs statfsBuf;
+            if (!statfs(pszNativeFsPath, &statfsBuf))
+            {
+                if (!strcmp("hfs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_HFS;
+                else if (!strcmp("apfs", statfsBuf.f_fstypename)) /** @todo verify apfs signature. */
+                    *penmType = RTFSTYPE_APFS;
+                else if (   !strcmp("fat", statfsBuf.f_fstypename)
+                         || !strcmp("msdos", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_FAT;
+                else if (!strcmp("ntfs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_NTFS;
+                else if (!strcmp("autofs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_AUTOFS;
+                else if (!strcmp("devfs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_DEVFS;
+                else if (!strcmp("nfs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_NFS;
+                else if (!strcmp("ufs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_UFS;
+                else if (!strcmp("zfs", statfsBuf.f_fstypename))
+                    *penmType = RTFSTYPE_ZFS;
+            }
+            else
+                rc = RTErrConvertFromErrno(errno);
+#endif
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeFsPath, pszFsPath);
+    }
+
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/posix/fs2-posix.cpp b/src/VBox/Runtime/r3/posix/fs2-posix.cpp
new file mode 100644
index 00000000..adbdecfe
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fs2-posix.cpp
@@ -0,0 +1,165 @@
+/* $Id: fs2-posix.cpp $ */
+/** @file
+ * IPRT - File System Helpers, POSIX, Part 2.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RTTIME_INCL_TIMESPEC
+#include <sys/time.h>
+#include <sys/param.h>
+#ifndef DEV_BSIZE
+# include <sys/stat.h>
+# if defined(RT_OS_HAIKU) && !defined(S_BLKSIZE)
+#  define S_BLKSIZE 512
+# endif
+# define DEV_BSIZE S_BLKSIZE /** @todo bird: add DEV_BSIZE to sys/param.h on OS/2. */
+#endif
+
+#include <iprt/fs.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/time.h>
+#include "internal/fs.h"
+
+
+/**
+ * Internal worker function which setups RTFSOBJINFO based on a UNIX stat struct.
+ *
+ * @param   pObjInfo        The file system object info structure to setup.
+ * @param   pStat           The stat structure to use.
+ * @param   pszName         The filename which this applies to (exe/hidden check).
+ * @param   cbName          The length of that filename. (optional, set 0)
+ */
+void rtFsConvertStatToObjInfo(PRTFSOBJINFO pObjInfo, const struct stat *pStat, const char *pszName, unsigned cbName)
+{
+    pObjInfo->cbObject    = pStat->st_size;
+    pObjInfo->cbAllocated = pStat->st_blocks * DEV_BSIZE;
+
+#ifdef HAVE_STAT_NSEC
+    RTTimeSpecAddNano(RTTimeSpecSetSeconds(&pObjInfo->AccessTime,       pStat->st_atime),     pStat->st_atimensec);
+    RTTimeSpecAddNano(RTTimeSpecSetSeconds(&pObjInfo->ModificationTime, pStat->st_mtime),     pStat->st_mtimensec);
+    RTTimeSpecAddNano(RTTimeSpecSetSeconds(&pObjInfo->ChangeTime,       pStat->st_ctime),     pStat->st_ctimensec);
+# ifdef HAVE_STAT_BIRTHTIME
+    RTTimeSpecAddNano(RTTimeSpecSetSeconds(&pObjInfo->BirthTime,        pStat->st_birthtime), pStat->st_birthtimensec);
+# endif
+
+#elif defined(HAVE_STAT_TIMESPEC_BRIEF)
+    RTTimeSpecSetTimespec(&pObjInfo->AccessTime,       &pStat->st_atim);
+    RTTimeSpecSetTimespec(&pObjInfo->ModificationTime, &pStat->st_mtim);
+    RTTimeSpecSetTimespec(&pObjInfo->ChangeTime,       &pStat->st_ctim);
+# ifdef HAVE_STAT_BIRTHTIME
+    RTTimeSpecSetTimespec(&pObjInfo->BirthTime,        &pStat->st_birthtim);
+# endif
+
+#elif defined(HAVE_STAT_TIMESPEC)
+    RTTimeSpecSetTimespec(&pObjInfo->AccessTime,       pStat->st_atimespec);
+    RTTimeSpecSetTimespec(&pObjInfo->ModificationTime, pStat->st_mtimespec);
+    RTTimeSpecSetTimespec(&pObjInfo->ChangeTime,       pStat->st_ctimespec);
+# ifdef HAVE_STAT_BIRTHTIME
+    RTTimeSpecSetTimespec(&pObjInfo->BirthTime,        pStat->st_birthtimespec);
+# endif
+
+#else /* just the normal stuff */
+    RTTimeSpecSetSeconds(&pObjInfo->AccessTime,       pStat->st_atime);
+    RTTimeSpecSetSeconds(&pObjInfo->ModificationTime, pStat->st_mtime);
+    RTTimeSpecSetSeconds(&pObjInfo->ChangeTime,       pStat->st_ctime);
+# ifdef HAVE_STAT_BIRTHTIME
+    RTTimeSpecSetSeconds(&pObjInfo->BirthTime,        pStat->st_birthtime);
+# endif
+#endif
+#ifndef HAVE_STAT_BIRTHTIME
+    pObjInfo->BirthTime = pObjInfo->ChangeTime;
+#endif
+
+    /* the file mode */
+    RTFMODE fMode = pStat->st_mode & RTFS_UNIX_MASK;
+    Assert(RTFS_UNIX_ISUID == S_ISUID);
+    Assert(RTFS_UNIX_ISGID == S_ISGID);
+#ifdef S_ISTXT
+    Assert(RTFS_UNIX_ISTXT == S_ISTXT);
+#elif defined(S_ISVTX)
+    Assert(RTFS_UNIX_ISTXT == S_ISVTX);
+#else
+#error "S_ISVTX / S_ISTXT isn't defined"
+#endif
+    Assert(RTFS_UNIX_IRWXU == S_IRWXU);
+    Assert(RTFS_UNIX_IRUSR == S_IRUSR);
+    Assert(RTFS_UNIX_IWUSR == S_IWUSR);
+    Assert(RTFS_UNIX_IXUSR == S_IXUSR);
+    Assert(RTFS_UNIX_IRWXG == S_IRWXG);
+    Assert(RTFS_UNIX_IRGRP == S_IRGRP);
+    Assert(RTFS_UNIX_IWGRP == S_IWGRP);
+    Assert(RTFS_UNIX_IXGRP == S_IXGRP);
+    Assert(RTFS_UNIX_IRWXO == S_IRWXO);
+    Assert(RTFS_UNIX_IROTH == S_IROTH);
+    Assert(RTFS_UNIX_IWOTH == S_IWOTH);
+    Assert(RTFS_UNIX_IXOTH == S_IXOTH);
+    Assert(RTFS_TYPE_FIFO == S_IFIFO);
+    Assert(RTFS_TYPE_DEV_CHAR == S_IFCHR);
+    Assert(RTFS_TYPE_DIRECTORY == S_IFDIR);
+    Assert(RTFS_TYPE_DEV_BLOCK == S_IFBLK);
+    Assert(RTFS_TYPE_FILE == S_IFREG);
+    Assert(RTFS_TYPE_SYMLINK == S_IFLNK);
+    Assert(RTFS_TYPE_SOCKET == S_IFSOCK);
+#ifdef S_IFWHT
+    Assert(RTFS_TYPE_WHITEOUT == S_IFWHT);
+#endif
+    Assert(RTFS_TYPE_MASK == S_IFMT);
+
+    pObjInfo->Attr.fMode  = rtFsModeFromUnix(fMode, pszName, cbName, 0);
+
+    /* additional unix attribs */
+    pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+    pObjInfo->Attr.u.Unix.uid             = pStat->st_uid;
+    pObjInfo->Attr.u.Unix.gid             = pStat->st_gid;
+    pObjInfo->Attr.u.Unix.cHardlinks      = pStat->st_nlink;
+    pObjInfo->Attr.u.Unix.INodeIdDevice   = pStat->st_dev;
+    pObjInfo->Attr.u.Unix.INodeId         = pStat->st_ino;
+#ifdef HAVE_STAT_FLAGS
+    pObjInfo->Attr.u.Unix.fFlags          = pStat->st_flags;
+#else
+    pObjInfo->Attr.u.Unix.fFlags          = 0;
+#endif
+#ifdef HAVE_STAT_GEN
+    pObjInfo->Attr.u.Unix.GenerationId    = pStat->st_gen;
+#else
+    pObjInfo->Attr.u.Unix.GenerationId    = 0;
+#endif
+    pObjInfo->Attr.u.Unix.Device          = pStat->st_rdev;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/fs3-posix.cpp b/src/VBox/Runtime/r3/posix/fs3-posix.cpp
new file mode 100644
index 00000000..368ae8e3
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/fs3-posix.cpp
@@ -0,0 +1,94 @@
+/* $Id: fs3-posix.cpp $ */
+/** @file
+ * IPRT - File System Helpers, POSIX, Part 3.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/fs.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include "internal/fs.h"
+
+#include <sys/time.h>
+#include <grp.h>
+#include <pwd.h>
+
+
+/**
+ * Set user-owner additional attributes.
+ *
+ * @param   pObjInfo            The object info to fill add attrs for.
+ * @param   uid                 The user id.
+ */
+void    rtFsObjInfoAttrSetUnixOwner(PRTFSOBJINFO pObjInfo, RTUID uid)
+{
+    pObjInfo->Attr.enmAdditional   = RTFSOBJATTRADD_UNIX_OWNER;
+    pObjInfo->Attr.u.UnixOwner.uid = uid;
+    pObjInfo->Attr.u.UnixOwner.szName[0] = '\0';
+
+    char            achBuf[_4K];
+    struct passwd   Pwd;
+    struct passwd  *pPwd;
+    int rc = getpwuid_r(uid, &Pwd, achBuf, sizeof(achBuf), &pPwd);
+    if (!rc && pPwd)
+        RTStrCopy(pObjInfo->Attr.u.UnixOwner.szName, sizeof(pObjInfo->Attr.u.UnixOwner.szName), pPwd->pw_name);
+}
+
+
+/**
+ * Set user-group additional attributes.
+ *
+ * @param   pObjInfo            The object info to fill add attrs for.
+ * @param   gid                 The group id.
+ */
+void rtFsObjInfoAttrSetUnixGroup(PRTFSOBJINFO pObjInfo, RTUID gid)
+{
+    pObjInfo->Attr.enmAdditional   = RTFSOBJATTRADD_UNIX_GROUP;
+    pObjInfo->Attr.u.UnixGroup.gid = gid;
+    pObjInfo->Attr.u.UnixGroup.szName[0] = '\0';
+
+    char            achBuf[_4K];
+    struct group    Grp;
+    struct group   *pGrp;
+
+    int rc = getgrgid_r(gid, &Grp, achBuf, sizeof(achBuf), &pGrp);
+    if (!rc && pGrp)
+        RTStrCopy(pObjInfo->Attr.u.UnixGroup.szName, sizeof(pObjInfo->Attr.u.UnixGroup.szName), pGrp->gr_name);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/ldrNative-posix.cpp b/src/VBox/Runtime/r3/posix/ldrNative-posix.cpp
new file mode 100644
index 00000000..9b33a0ff
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/ldrNative-posix.cpp
@@ -0,0 +1,207 @@
+/* $Id: ldrNative-posix.cpp $ */
+/** @file
+ * IPRT - Binary Image Loader, POSIX native.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_LDR
+#include <dlfcn.h>
+
+#include <iprt/ldr.h>
+#include <iprt/assert.h>
+#include <iprt/path.h>
+#include <iprt/alloca.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/ldr.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+static const char g_szSuff[] = ".DLL";
+#elif defined(RT_OS_L4)
+static const char g_szSuff[] = ".s.so";
+#elif defined(RT_OS_DARWIN)
+static const char g_szSuff[] = ".dylib";
+#else
+static const char g_szSuff[] = ".so";
+#endif
+
+
+DECLHIDDEN(int) rtldrNativeLoad(const char *pszFilename, uintptr_t *phHandle, uint32_t fFlags, PRTERRINFO pErrInfo)
+{
+    /*
+     * Do we need to add an extension?
+     */
+    if (!RTPathHasSuffix(pszFilename) && !(fFlags & RTLDRLOAD_FLAGS_NO_SUFFIX))
+    {
+        size_t cch = strlen(pszFilename);
+        char *psz = (char *)alloca(cch + sizeof(g_szSuff));
+        if (!psz)
+            return RTErrInfoSet(pErrInfo, VERR_NO_MEMORY, "alloca failed");
+        memcpy(psz, pszFilename, cch);
+        memcpy(psz + cch, g_szSuff, sizeof(g_szSuff));
+        pszFilename = psz;
+    }
+
+    /*
+     * Attempt load.
+     */
+    int fFlagsNative = RTLD_NOW;
+    if (fFlags & RTLDRLOAD_FLAGS_GLOBAL)
+        fFlagsNative |= RTLD_GLOBAL;
+    else
+        fFlagsNative |= RTLD_LOCAL;
+    void *pvMod = dlopen(pszFilename, fFlagsNative);
+    if (pvMod)
+    {
+        *phHandle = (uintptr_t)pvMod;
+        return VINF_SUCCESS;
+    }
+
+    const char *pszDlError = dlerror();
+    RTErrInfoSet(pErrInfo, VERR_FILE_NOT_FOUND, pszDlError);
+    LogRel(("rtldrNativeLoad: dlopen('%s', RTLD_NOW | RTLD_LOCAL) failed: %s\n", pszFilename, pszDlError));
+    return VERR_FILE_NOT_FOUND;
+}
+
+
+DECLCALLBACK(int) rtldrNativeGetSymbol(PRTLDRMODINTERNAL pMod, const char *pszSymbol, void **ppvValue)
+{
+    PRTLDRMODNATIVE pModNative = (PRTLDRMODNATIVE)pMod;
+#ifdef RT_OS_OS2
+    /* Prefix the symbol with an underscore (assuming __cdecl/gcc-default). */
+    size_t cch = strlen(pszSymbol);
+    char *psz = (char *)alloca(cch + 2);
+    psz[0] = '_';
+    memcpy(psz + 1, pszSymbol, cch + 1);
+    pszSymbol = psz;
+#endif
+    *ppvValue = dlsym((void *)pModNative->hNative, pszSymbol);
+    if (*ppvValue)
+        return VINF_SUCCESS;
+    return VERR_SYMBOL_NOT_FOUND;
+}
+
+
+DECLCALLBACK(int) rtldrNativeClose(PRTLDRMODINTERNAL pMod)
+{
+    PRTLDRMODNATIVE pModNative = (PRTLDRMODNATIVE)pMod;
+#ifdef __SANITIZE_ADDRESS__
+    /* If we are compiled with enabled address sanitizer (gcc/llvm), don't
+     * unload the module to prevent <unknown module> in the stack trace */
+    pModNative->fFlags |= RTLDRLOAD_FLAGS_NO_UNLOAD;
+#endif
+    if (   (pModNative->fFlags & RTLDRLOAD_FLAGS_NO_UNLOAD)
+        || !dlclose((void *)pModNative->hNative))
+    {
+        pModNative->hNative = (uintptr_t)0;
+        return VINF_SUCCESS;
+    }
+    Log(("rtldrNativeFree: dlclose(%p) failed: %s\n", pModNative->hNative, dlerror()));
+    return VERR_GENERAL_FAILURE;
+}
+
+
+DECLHIDDEN(int) rtldrNativeLoadSystem(const char *pszFilename, const char *pszExt, uint32_t fFlags, PRTLDRMOD phLdrMod)
+{
+    /*
+     * For the present we ASSUME that we can trust dlopen to load what we want
+     * when not specifying a path.  There seems to be very little we can do to
+     * restrict the places dlopen will search for library without doing
+     * auditing (linux) or something like that.
+     */
+    Assert(strchr(pszFilename, '/') == NULL);
+
+    uint32_t const fFlags2 = fFlags & ~(RTLDRLOAD_FLAGS_SO_VER_BEGIN_MASK | RTLDRLOAD_FLAGS_SO_VER_END_MASK);
+
+    /*
+     * If no suffix is given and we haven't got any RTLDRLOAD_FLAGS_SO_VER_ range to work
+     * with, we can call RTLdrLoadEx directly.
+     */
+    if (!pszExt)
+    {
+#if !defined(RT_OS_DARWIN) && !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS)
+        if (    (fFlags & RTLDRLOAD_FLAGS_SO_VER_BEGIN_MASK) >> RTLDRLOAD_FLAGS_SO_VER_BEGIN_SHIFT
+             == (fFlags & RTLDRLOAD_FLAGS_SO_VER_END_MASK)   >> RTLDRLOAD_FLAGS_SO_VER_END_SHIFT)
+#endif
+            return RTLdrLoadEx(pszFilename, phLdrMod, fFlags2, NULL);
+        pszExt = "";
+    }
+
+    /*
+     * Combine filename and suffix and then do the loading.
+     */
+    size_t const cchFilename = strlen(pszFilename);
+    size_t const cchSuffix   = strlen(pszExt);
+    char *pszTmp = (char *)alloca(cchFilename + cchSuffix + 16 + 1);
+    memcpy(pszTmp, pszFilename, cchFilename);
+    memcpy(&pszTmp[cchFilename], pszExt, cchSuffix);
+    pszTmp[cchFilename + cchSuffix] = '\0';
+
+    int rc = RTLdrLoadEx(pszTmp, phLdrMod, fFlags2, NULL);
+
+#if !defined(RT_OS_DARWIN) && !defined(RT_OS_OS2) && !defined(RT_OS_WINDOWS)
+    /*
+     * If no version was given after the .so and do .so.MAJOR search according
+     * to the range in the fFlags.
+     */
+    if (RT_FAILURE(rc) && !(fFlags & RTLDRLOAD_FLAGS_NO_SUFFIX))
+    {
+        const char *pszActualSuff = RTPathSuffix(pszTmp);
+        if (pszActualSuff && strcmp(pszActualSuff, ".so") == 0)
+        {
+            int32_t const iBegin    = (fFlags & RTLDRLOAD_FLAGS_SO_VER_BEGIN_MASK) >> RTLDRLOAD_FLAGS_SO_VER_BEGIN_SHIFT;
+            int32_t const iEnd      = (fFlags & RTLDRLOAD_FLAGS_SO_VER_END_MASK)   >> RTLDRLOAD_FLAGS_SO_VER_END_SHIFT;
+            int32_t const iIncr     = iBegin <= iEnd ? 1 : -1;
+            for (int32_t  iMajorVer = iBegin; iMajorVer != iEnd; iMajorVer += iIncr)
+            {
+                RTStrPrintf(&pszTmp[cchFilename + cchSuffix], 16 + 1, ".%d", iMajorVer);
+                rc = RTLdrLoadEx(pszTmp, phLdrMod, fFlags2, NULL);
+                if (RT_SUCCESS(rc))
+                    break;
+            }
+        }
+    }
+#endif
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/localipc-posix.cpp b/src/VBox/Runtime/r3/posix/localipc-posix.cpp
new file mode 100644
index 00000000..131d78cf
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/localipc-posix.cpp
@@ -0,0 +1,1172 @@
+/* $Id: localipc-posix.cpp $ */
+/** @file
+ * IPRT - Local IPC Server & Client, Posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_LOCALIPC
+#include "internal/iprt.h"
+#include <iprt/localipc.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/log.h>
+#include <iprt/poll.h>
+#include <iprt/socket.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include <iprt/path.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#ifndef RT_OS_OS2
+# include <sys/poll.h>
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#ifndef AF_LOCAL
+# define AF_LOCAL AF_UNIX
+#endif
+
+#include "internal/magics.h"
+#include "internal/path.h"
+#include "internal/socket.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Local IPC service instance, POSIX.
+ */
+typedef struct RTLOCALIPCSERVERINT
+{
+    /** The magic (RTLOCALIPCSERVER_MAGIC). */
+    uint32_t            u32Magic;
+    /** The creation flags. */
+    uint32_t            fFlags;
+    /** Critical section protecting the structure. */
+    RTCRITSECT          CritSect;
+    /** The number of references to the instance. */
+    uint32_t volatile   cRefs;
+    /** Indicates that there is a pending cancel request. */
+    bool volatile       fCancelled;
+    /** The server socket. */
+    RTSOCKET            hSocket;
+    /** Thread currently listening for clients. */
+    RTTHREAD            hListenThread;
+    /** The name we bound the server to (native charset encoding). */
+    struct sockaddr_un  Name;
+} RTLOCALIPCSERVERINT;
+/** Pointer to a local IPC server instance (POSIX). */
+typedef RTLOCALIPCSERVERINT *PRTLOCALIPCSERVERINT;
+
+
+/**
+ * Local IPC session instance, POSIX.
+ */
+typedef struct RTLOCALIPCSESSIONINT
+{
+    /** The magic (RTLOCALIPCSESSION_MAGIC). */
+    uint32_t            u32Magic;
+    /** Critical section protecting the structure. */
+    RTCRITSECT          CritSect;
+    /** The number of references to the instance. */
+    uint32_t volatile   cRefs;
+    /** Indicates that there is a pending cancel request. */
+    bool volatile       fCancelled;
+    /** Set if this is the server side, clear if the client. */
+    bool                fServerSide;
+    /** The client socket. */
+    RTSOCKET            hSocket;
+    /** Thread currently doing read related activites. */
+    RTTHREAD            hWriteThread;
+    /** Thread currently doing write related activies. */
+    RTTHREAD            hReadThread;
+} RTLOCALIPCSESSIONINT;
+/** Pointer to a local IPC session instance (Windows). */
+typedef RTLOCALIPCSESSIONINT *PRTLOCALIPCSESSIONINT;
+
+
+/** Local IPC name prefix for portable names. */
+#define RTLOCALIPC_POSIX_NAME_PREFIX    "/tmp/.iprt-localipc-"
+
+
+/**
+ * Validates the user specified name.
+ *
+ * @returns IPRT status code.
+ * @param   pszName             The name to validate.
+ * @param   fNative             Whether it's a native name or a portable name.
+ */
+static int rtLocalIpcPosixValidateName(const char *pszName, bool fNative)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertReturn(*pszName, VERR_INVALID_NAME);
+
+    if (!fNative)
+    {
+        for (;;)
+        {
+            char ch = *pszName++;
+            if (!ch)
+                break;
+            AssertReturn(!RT_C_IS_CNTRL(ch), VERR_INVALID_NAME);
+            AssertReturn((unsigned)ch < 0x80, VERR_INVALID_NAME);
+            AssertReturn(ch != '\\', VERR_INVALID_NAME);
+            AssertReturn(ch != '/', VERR_INVALID_NAME);
+        }
+    }
+    else
+    {
+        int rc = RTStrValidateEncoding(pszName);
+        AssertRCReturn(rc, rc);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Constructs a local (unix) domain socket name.
+ *
+ * @returns IPRT status code.
+ * @param   pAddr               The address structure to construct the name in.
+ * @param   pcbAddr             Where to return the address size.
+ * @param   pszName             The user specified name (valid).
+ * @param   fNative             Whether it's a native name or a portable name.
+ */
+static int rtLocalIpcPosixConstructName(struct sockaddr_un *pAddr, uint8_t *pcbAddr, const char *pszName, bool fNative)
+{
+    const char *pszNativeName;
+    int rc = rtPathToNative(&pszNativeName, pszName, NULL /*pszBasePath not support*/);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cchNativeName = strlen(pszNativeName);
+        size_t cbFull = !fNative ? cchNativeName + sizeof(RTLOCALIPC_POSIX_NAME_PREFIX) : cchNativeName + 1;
+        if (cbFull <= sizeof(pAddr->sun_path))
+        {
+            RT_ZERO(*pAddr);
+#ifdef RT_OS_OS2 /* Size must be exactly right on OS/2. */
+            *pcbAddr = sizeof(*pAddr);
+#else
+            *pcbAddr = RT_UOFFSETOF(struct sockaddr_un, sun_path) + (uint8_t)cbFull;
+#endif
+#ifdef HAVE_SUN_LEN_MEMBER
+            pAddr->sun_len     = *pcbAddr;
+#endif
+            pAddr->sun_family  = AF_LOCAL;
+
+            if (!fNative)
+            {
+                memcpy(pAddr->sun_path, RTLOCALIPC_POSIX_NAME_PREFIX, sizeof(RTLOCALIPC_POSIX_NAME_PREFIX) - 1);
+                memcpy(&pAddr->sun_path[sizeof(RTLOCALIPC_POSIX_NAME_PREFIX) - 1], pszNativeName, cchNativeName + 1);
+            }
+            else
+                memcpy(pAddr->sun_path, pszNativeName, cchNativeName + 1);
+        }
+        else
+            rc = VERR_FILENAME_TOO_LONG;
+        rtPathFreeNative(pszNativeName, pszName);
+    }
+    return rc;
+}
+
+
+
+RTDECL(int) RTLocalIpcServerCreate(PRTLOCALIPCSERVER phServer, const char *pszName, uint32_t fFlags)
+{
+    /*
+     * Parameter validation.
+     */
+    AssertPtrReturn(phServer, VERR_INVALID_POINTER);
+    *phServer = NIL_RTLOCALIPCSERVER;
+    AssertReturn(!(fFlags & ~RTLOCALIPC_FLAGS_VALID_MASK), VERR_INVALID_FLAGS);
+    int rc = rtLocalIpcPosixValidateName(pszName, RT_BOOL(fFlags & RTLOCALIPC_FLAGS_NATIVE_NAME));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Allocate memory for the instance and initialize it.
+         */
+        PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)RTMemAllocZ(sizeof(*pThis));
+        if (pThis)
+        {
+            pThis->u32Magic      = RTLOCALIPCSERVER_MAGIC;
+            pThis->fFlags        = fFlags;
+            pThis->cRefs         = 1;
+            pThis->fCancelled    = false;
+            pThis->hListenThread = NIL_RTTHREAD;
+            rc = RTCritSectInit(&pThis->CritSect);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Create the local (unix) socket and bind to it.
+                 */
+                rc = rtSocketCreate(&pThis->hSocket, AF_LOCAL, SOCK_STREAM, 0 /*iProtocol*/, false /*fInheritable*/);
+                if (RT_SUCCESS(rc))
+                {
+                    signal(SIGPIPE, SIG_IGN); /* Required on solaris, at least. */
+
+                    uint8_t cbAddr;
+                    rc = rtLocalIpcPosixConstructName(&pThis->Name, &cbAddr, pszName,
+                                                      RT_BOOL(fFlags & RTLOCALIPC_FLAGS_NATIVE_NAME));
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = rtSocketBindRawAddr(pThis->hSocket, &pThis->Name, cbAddr);
+                        if (rc == VERR_NET_ADDRESS_IN_USE)
+                        {
+                            unlink(pThis->Name.sun_path);
+                            rc = rtSocketBindRawAddr(pThis->hSocket, &pThis->Name, cbAddr);
+                        }
+                        if (RT_SUCCESS(rc))
+                        {
+                            rc = rtSocketListen(pThis->hSocket, 16);
+                            if (RT_SUCCESS(rc))
+                            {
+                                LogFlow(("RTLocalIpcServerCreate: Created %p (%s)\n", pThis, pThis->Name.sun_path));
+                                *phServer = pThis;
+                                return VINF_SUCCESS;
+                            }
+                            unlink(pThis->Name.sun_path);
+                        }
+                    }
+                    RTSocketRelease(pThis->hSocket);
+                }
+                RTCritSectDelete(&pThis->CritSect);
+            }
+            RTMemFree(pThis);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    Log(("RTLocalIpcServerCreate: failed, rc=%Rrc\n", rc));
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcServerGrantGroupAccess(RTLOCALIPCSERVER hServer, RTGID gid)
+{
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->Name.sun_path[0] != '\0', VERR_INVALID_STATE);
+
+    if (chown(pThis->Name.sun_path, (uid_t)-1, gid) == 0)
+    {
+        if (chmod(pThis->Name.sun_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP) == 0)
+        {
+            LogRel2(("RTLocalIpcServerGrantGroupAccess: IPC socket %s access has been granted to group %RTgid\n",
+                     pThis->Name.sun_path, gid));
+            return VINF_SUCCESS;
+        }
+        LogRel(("RTLocalIpcServerGrantGroupAccess: cannot grant IPC socket %s write permission to group %RTgid: errno=%d\n",
+                pThis->Name.sun_path, gid, errno));
+    }
+    else
+        LogRel(("RTLocalIpcServerGrantGroupAccess: cannot change IPC socket %s group ownership to %RTgid: errno=%d\n",
+                pThis->Name.sun_path, gid, errno));
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTLocalIpcServerSetAccessMode(RTLOCALIPCSERVER hServer, RTFMODE fMode)
+{
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->Name.sun_path[0] != '\0', VERR_INVALID_STATE);
+
+    if (chmod(pThis->Name.sun_path, fMode & RTFS_UNIX_ALL_ACCESS_PERMS) == 0)
+        return VINF_SUCCESS;
+
+    return RTErrConvertFromErrno(errno);
+}
+
+
+/**
+ * Retains a reference to the server instance.
+ *
+ * @returns
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(void) rtLocalIpcServerRetain(PRTLOCALIPCSERVERINT pThis)
+{
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs); RT_NOREF_PV(cRefs);
+}
+
+
+/**
+ * Server instance destructor.
+ *
+ * @returns VINF_OBJECT_DESTROYED
+ * @param   pThis               The server instance.
+ */
+static int rtLocalIpcServerDtor(PRTLOCALIPCSERVERINT pThis)
+{
+    pThis->u32Magic = ~RTLOCALIPCSERVER_MAGIC;
+    if (RTSocketRelease(pThis->hSocket) == 0)
+        Log(("rtLocalIpcServerDtor: Released socket\n"));
+    else
+        Log(("rtLocalIpcServerDtor: Socket still has references (impossible?)\n"));
+    RTCritSectDelete(&pThis->CritSect);
+    unlink(pThis->Name.sun_path);
+    RTMemFree(pThis);
+    return VINF_OBJECT_DESTROYED;
+}
+
+
+/**
+ * Releases a reference to the server instance.
+ *
+ * @returns VINF_SUCCESS if only release, VINF_OBJECT_DESTROYED if destroyed.
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(int) rtLocalIpcServerRelease(PRTLOCALIPCSERVERINT pThis)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (!cRefs)
+        return rtLocalIpcServerDtor(pThis);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The core of RTLocalIpcServerCancel, used by both the destroy and cancel APIs.
+ *
+ * @returns IPRT status code
+ * @param   pThis               The server instance.
+ */
+static int rtLocalIpcServerCancel(PRTLOCALIPCSERVERINT pThis)
+{
+    RTCritSectEnter(&pThis->CritSect);
+    pThis->fCancelled = true;
+    Log(("rtLocalIpcServerCancel:\n"));
+    if (pThis->hListenThread != NIL_RTTHREAD)
+        RTThreadPoke(pThis->hListenThread);
+    RTCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+
+
+RTDECL(int) RTLocalIpcServerDestroy(RTLOCALIPCSERVER hServer)
+{
+    /*
+     * Validate input.
+     */
+    if (hServer == NIL_RTLOCALIPCSERVER)
+        return VINF_SUCCESS;
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the server, releasing the caller's reference to the instance
+     * data and making sure any other thread in the listen API will wake up.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTLOCALIPCSERVER_MAGIC, RTLOCALIPCSERVER_MAGIC), VERR_WRONG_ORDER);
+
+    rtLocalIpcServerCancel(pThis);
+    return rtLocalIpcServerRelease(pThis);
+}
+
+
+RTDECL(int) RTLocalIpcServerCancel(RTLOCALIPCSERVER hServer)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcServerRetain(pThis);
+    rtLocalIpcServerCancel(pThis);
+    rtLocalIpcServerRelease(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTLocalIpcServerListen(RTLOCALIPCSERVER hServer, PRTLOCALIPCSESSION phClientSession)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Begin listening.
+     */
+    rtLocalIpcServerRetain(pThis);
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hListenThread == NIL_RTTHREAD)
+        {
+            pThis->hListenThread = RTThreadSelf();
+
+            /*
+             * The listening retry loop.
+             */
+            for (;;)
+            {
+                if (!pThis->fCancelled)
+                {
+                    rc = RTCritSectLeave(&pThis->CritSect);
+                    AssertRCBreak(rc);
+
+                    struct sockaddr_un  Addr;
+                    size_t              cbAddr = sizeof(Addr);
+                    RTSOCKET            hClient;
+                    Log(("RTLocalIpcServerListen: Calling rtSocketAccept...\n"));
+                    rc = rtSocketAccept(pThis->hSocket, &hClient, (struct sockaddr *)&Addr, &cbAddr);
+                    Log(("RTLocalIpcServerListen: rtSocketAccept returns %Rrc.\n", rc));
+
+                    int rc2 = RTCritSectEnter(&pThis->CritSect);
+                    AssertRCBreakStmt(rc2, rc = RT_SUCCESS(rc) ? rc2 : rc);
+
+                    if (RT_SUCCESS(rc))
+                    {
+                        /*
+                         * Create a client session.
+                         */
+                        PRTLOCALIPCSESSIONINT pSession = (PRTLOCALIPCSESSIONINT)RTMemAllocZ(sizeof(*pSession));
+                        if (pSession)
+                        {
+                            pSession->u32Magic      = RTLOCALIPCSESSION_MAGIC;
+                            pSession->cRefs         = 1;
+                            pSession->fCancelled    = false;
+                            pSession->fServerSide   = true;
+                            pSession->hSocket       = hClient;
+                            pSession->hReadThread   = NIL_RTTHREAD;
+                            pSession->hWriteThread  = NIL_RTTHREAD;
+                            rc = RTCritSectInit(&pSession->CritSect);
+                            if (RT_SUCCESS(rc))
+                            {
+                                Log(("RTLocalIpcServerListen: Returning new client session: %p\n", pSession));
+                                *phClientSession = pSession;
+                                break;
+                            }
+
+                            RTMemFree(pSession);
+                        }
+                        else
+                            rc = VERR_NO_MEMORY;
+                    }
+                    else if (   rc != VERR_INTERRUPTED
+                             && rc != VERR_TRY_AGAIN)
+                        break;
+                }
+                else
+                {
+                    rc = VERR_CANCELLED;
+                    break;
+                }
+            }
+
+            pThis->hListenThread = NIL_RTTHREAD;
+        }
+        else
+        {
+            AssertFailed();
+            rc = VERR_RESOURCE_BUSY;
+        }
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+    rtLocalIpcServerRelease(pThis);
+
+    Log(("RTLocalIpcServerListen: returns %Rrc\n", rc));
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionConnect(PRTLOCALIPCSESSION phSession, const char *pszName, uint32_t fFlags)
+{
+    /*
+     * Parameter validation.
+     */
+    AssertPtrReturn(phSession, VERR_INVALID_POINTER);
+    *phSession = NIL_RTLOCALIPCSESSION;
+
+    AssertReturn(!(fFlags & ~RTLOCALIPC_C_FLAGS_VALID_MASK), VERR_INVALID_FLAGS);
+
+    int rc = rtLocalIpcPosixValidateName(pszName, RT_BOOL(fFlags & RTLOCALIPC_C_FLAGS_NATIVE_NAME));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Allocate memory for the instance and initialize it.
+         */
+        PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)RTMemAllocZ(sizeof(*pThis));
+        if (pThis)
+        {
+            pThis->u32Magic         = RTLOCALIPCSESSION_MAGIC;
+            pThis->cRefs            = 1;
+            pThis->fCancelled       = false;
+            pThis->fServerSide      = false;
+            pThis->hSocket          = NIL_RTSOCKET;
+            pThis->hReadThread      = NIL_RTTHREAD;
+            pThis->hWriteThread     = NIL_RTTHREAD;
+            rc = RTCritSectInit(&pThis->CritSect);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Create the local (unix) socket and try connect to the server.
+                 */
+                rc = rtSocketCreate(&pThis->hSocket, AF_LOCAL, SOCK_STREAM, 0 /*iProtocol*/, false /*fInheritable*/);
+                if (RT_SUCCESS(rc))
+                {
+                    signal(SIGPIPE, SIG_IGN); /* Required on solaris, at least. */
+
+                    struct sockaddr_un  Addr;
+                    uint8_t             cbAddr;
+                    rc = rtLocalIpcPosixConstructName(&Addr, &cbAddr, pszName, RT_BOOL(fFlags & RTLOCALIPC_C_FLAGS_NATIVE_NAME));
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = rtSocketConnectRaw(pThis->hSocket, &Addr, cbAddr);
+                        if (RT_SUCCESS(rc))
+                        {
+                            *phSession = pThis;
+                            Log(("RTLocalIpcSessionConnect: Returns new session %p\n", pThis));
+                            return VINF_SUCCESS;
+                        }
+                    }
+                    RTSocketRelease(pThis->hSocket);
+                }
+                RTCritSectDelete(&pThis->CritSect);
+            }
+            RTMemFree(pThis);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    Log(("RTLocalIpcSessionConnect: returns %Rrc\n", rc));
+    return rc;
+}
+
+
+/**
+ * Retains a reference to the session instance.
+ *
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(void) rtLocalIpcSessionRetain(PRTLOCALIPCSESSIONINT pThis)
+{
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs); RT_NOREF_PV(cRefs);
+}
+
+
+RTDECL(uint32_t) RTLocalIpcSessionRetain(RTLOCALIPCSESSION hSession)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs);
+    return cRefs;
+}
+
+
+/**
+ * Session instance destructor.
+ *
+ * @returns VINF_OBJECT_DESTROYED
+ * @param   pThis               The server instance.
+ */
+static int rtLocalIpcSessionDtor(PRTLOCALIPCSESSIONINT pThis)
+{
+    pThis->u32Magic = ~RTLOCALIPCSESSION_MAGIC;
+    if (RTSocketRelease(pThis->hSocket) == 0)
+        Log(("rtLocalIpcSessionDtor: Released socket\n"));
+    else
+        Log(("rtLocalIpcSessionDtor: Socket still has references (impossible?)\n"));
+    RTCritSectDelete(&pThis->CritSect);
+    RTMemFree(pThis);
+    return VINF_OBJECT_DESTROYED;
+}
+
+
+/**
+ * Releases a reference to the session instance.
+ *
+ * @returns VINF_SUCCESS or VINF_OBJECT_DESTROYED as appropriate.
+ * @param   pThis               The session instance.
+ */
+DECLINLINE(int) rtLocalIpcSessionRelease(PRTLOCALIPCSESSIONINT pThis)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (!cRefs)
+        return rtLocalIpcSessionDtor(pThis);
+    Log(("rtLocalIpcSessionRelease: %u refs left\n", cRefs));
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTLocalIpcSessionRelease(RTLOCALIPCSESSION hSession)
+{
+    if (hSession == NIL_RTLOCALIPCSESSION)
+        return 0;
+
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (cRefs)
+        Log(("RTLocalIpcSessionRelease: %u refs left\n", cRefs));
+    else
+        rtLocalIpcSessionDtor(pThis);
+    return cRefs;
+}
+
+
+/**
+ * The core of RTLocalIpcSessionCancel, used by both the destroy and cancel APIs.
+ *
+ * @returns IPRT status code
+ * @param   pThis               The session instance.
+ */
+static int rtLocalIpcSessionCancel(PRTLOCALIPCSESSIONINT pThis)
+{
+    RTCritSectEnter(&pThis->CritSect);
+    pThis->fCancelled = true;
+    Log(("rtLocalIpcSessionCancel:\n"));
+    if (pThis->hReadThread != NIL_RTTHREAD)
+        RTThreadPoke(pThis->hReadThread);
+    if (pThis->hWriteThread != NIL_RTTHREAD)
+        RTThreadPoke(pThis->hWriteThread);
+    RTCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTLocalIpcSessionClose(RTLOCALIPCSESSION hSession)
+{
+    /*
+     * Validate input.
+     */
+    if (hSession == NIL_RTLOCALIPCSESSION)
+        return VINF_SUCCESS;
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the session, releasing the caller's reference to the instance
+     * data and making sure any other thread in the listen API will wake up.
+     */
+    Log(("RTLocalIpcSessionClose:\n"));
+
+    rtLocalIpcSessionCancel(pThis);
+    return rtLocalIpcSessionRelease(pThis);
+}
+
+
+RTDECL(int) RTLocalIpcSessionCancel(RTLOCALIPCSESSION hSession)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcSessionRetain(pThis);
+    rtLocalIpcSessionCancel(pThis);
+    rtLocalIpcSessionRelease(pThis);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks if the socket has has a HUP condition after reading zero bytes.
+ *
+ * @returns true if HUP, false if no.
+ * @param   pThis       The IPC session handle.
+ */
+static bool rtLocalIpcPosixHasHup(PRTLOCALIPCSESSIONINT pThis)
+{
+    int fdNative = RTSocketToNative(pThis->hSocket);
+
+#if !defined(RT_OS_OS2) && !defined(RT_OS_SOLARIS)
+    struct pollfd PollFd;
+    RT_ZERO(PollFd);
+    PollFd.fd      = fdNative;
+    PollFd.events  = POLLHUP | POLLERR;
+    if (poll(&PollFd, 1, 0) <= 0)
+        return false;
+    if (!(PollFd.revents & (POLLHUP | POLLERR)))
+        return false;
+#else  /* RT_OS_OS2 || RT_OS_SOLARIS */
+    /*
+     * OS/2:    No native poll, do zero byte send to check for EPIPE.
+     * Solaris: We don't get POLLHUP.
+     */
+    uint8_t bDummy;
+    ssize_t rcSend = send(fdNative, &bDummy, 0, 0);
+    if (rcSend >= 0 || (errno != EPIPE && errno != ECONNRESET))
+        return false;
+#endif /* RT_OS_OS2 || RT_OS_SOLARIS */
+
+    /*
+     * We've established EPIPE.  Now make sure there aren't any last bytes to
+     * read that came in between the recv made by the caller and the disconnect.
+     */
+    uint8_t bPeek;
+    ssize_t rcRecv = recv(fdNative, &bPeek, 1, MSG_DONTWAIT | MSG_PEEK);
+    return rcRecv <= 0;
+}
+
+
+RTDECL(int) RTLocalIpcSessionRead(RTLOCALIPCSESSION hSession, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hReadThread == NIL_RTTHREAD)
+        {
+            pThis->hReadThread = RTThreadSelf();
+
+            for (;;)
+            {
+                if (!pThis->fCancelled)
+                {
+                    rc = RTCritSectLeave(&pThis->CritSect);
+                    AssertRCBreak(rc);
+
+                    rc = RTSocketRead(pThis->hSocket, pvBuf, cbToRead, pcbRead);
+
+                    /* Detect broken pipe. */
+                    if (rc == VINF_SUCCESS)
+                    {
+                        if (!pcbRead || *pcbRead)
+                        { /* likely */ }
+                        else if (rtLocalIpcPosixHasHup(pThis))
+                            rc = VERR_BROKEN_PIPE;
+                    }
+                    else if (rc == VERR_NET_CONNECTION_RESET_BY_PEER || rc == VERR_NET_SHUTDOWN)
+                        rc = VERR_BROKEN_PIPE;
+
+                    int rc2 = RTCritSectEnter(&pThis->CritSect);
+                    AssertRCBreakStmt(rc2, rc = RT_SUCCESS(rc) ? rc2 : rc);
+
+                    if (   rc == VERR_INTERRUPTED
+                        || rc == VERR_TRY_AGAIN)
+                        continue;
+                }
+                else
+                    rc = VERR_CANCELLED;
+                break;
+            }
+
+            pThis->hReadThread = NIL_RTTHREAD;
+        }
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionReadNB(RTLOCALIPCSESSION hSession, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hReadThread == NIL_RTTHREAD)
+        {
+            pThis->hReadThread = RTThreadSelf(); /* not really required, but whatever. */
+
+            for (;;)
+            {
+                if (!pThis->fCancelled)
+                {
+                    rc = RTSocketReadNB(pThis->hSocket, pvBuf, cbToRead, pcbRead);
+
+                    /* Detect broken pipe. */
+                    if (rc == VINF_SUCCESS)
+                    {
+                        if (!pcbRead || *pcbRead)
+                        { /* likely */ }
+                        else if (rtLocalIpcPosixHasHup(pThis))
+                            rc = VERR_BROKEN_PIPE;
+                    }
+                    else if (rc == VERR_NET_CONNECTION_RESET_BY_PEER || rc == VERR_NET_SHUTDOWN)
+                        rc = VERR_BROKEN_PIPE;
+
+                    if (rc == VERR_INTERRUPTED)
+                        continue;
+                }
+                else
+                    rc = VERR_CANCELLED;
+                break;
+            }
+
+            pThis->hReadThread = NIL_RTTHREAD;
+        }
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionWrite(RTLOCALIPCSESSION hSession, const void *pvBuf, size_t cbToWrite)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hWriteThread == NIL_RTTHREAD)
+        {
+            pThis->hWriteThread = RTThreadSelf();
+
+            for (;;)
+            {
+                if (!pThis->fCancelled)
+                {
+                    rc = RTCritSectLeave(&pThis->CritSect);
+                    AssertRCBreak(rc);
+
+                    rc = RTSocketWrite(pThis->hSocket, pvBuf, cbToWrite);
+
+                    int rc2 = RTCritSectEnter(&pThis->CritSect);
+                    AssertRCBreakStmt(rc2, rc = RT_SUCCESS(rc) ? rc2 : rc);
+
+                    if (   rc == VERR_INTERRUPTED
+                        || rc == VERR_TRY_AGAIN)
+                        continue;
+                }
+                else
+                    rc = VERR_CANCELLED;
+                break;
+            }
+
+            pThis->hWriteThread = NIL_RTTHREAD;
+        }
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionFlush(RTLOCALIPCSESSION hSession)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * This is a no-op because apparently write doesn't return until the
+     * result is read.  At least that's what the reply to a 2003-04-08 LKML
+     * posting title "fsync() on unix domain sockets?" indicates.
+     *
+     * For conformity, make sure there isn't any active writes concurrent to this call.
+     */
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hWriteThread == NIL_RTTHREAD)
+            rc = RTCritSectLeave(&pThis->CritSect);
+        else
+        {
+            rc = RTCritSectLeave(&pThis->CritSect);
+            if (RT_SUCCESS(rc))
+                rc = VERR_RESOURCE_BUSY;
+        }
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionWaitForData(RTLOCALIPCSESSION hSession, uint32_t cMillies)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the job.
+     */
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->hReadThread == NIL_RTTHREAD)
+        {
+            pThis->hReadThread = RTThreadSelf();
+            uint64_t const msStart = RTTimeMilliTS();
+            RTMSINTERVAL const cMsOriginalTimeout = cMillies;
+
+            for (;;)
+            {
+                if (!pThis->fCancelled)
+                {
+                    rc = RTCritSectLeave(&pThis->CritSect);
+                    AssertRCBreak(rc);
+
+                    uint32_t fEvents = 0;
+#ifdef RT_OS_OS2
+                    /* This doesn't give us any error condition on hangup, so use HUP check. */
+                    Log(("RTLocalIpcSessionWaitForData: Calling RTSocketSelectOneEx...\n"));
+                    rc = RTSocketSelectOneEx(pThis->hSocket, RTPOLL_EVT_READ | RTPOLL_EVT_ERROR, &fEvents, cMillies);
+                    Log(("RTLocalIpcSessionWaitForData: RTSocketSelectOneEx returns %Rrc, fEvents=%#x\n", rc, fEvents));
+                    if (RT_SUCCESS(rc) && fEvents == RTPOLL_EVT_READ && rtLocalIpcPosixHasHup(pThis))
+                        rc = VERR_BROKEN_PIPE;
+#else
+/** @todo RTSocketPoll? */
+                    /* POLLHUP will be set on hangup. */
+                    struct pollfd PollFd;
+                    RT_ZERO(PollFd);
+                    PollFd.fd      = RTSocketToNative(pThis->hSocket);
+                    PollFd.events  = POLLHUP | POLLERR | POLLIN;
+                    Log(("RTLocalIpcSessionWaitForData: Calling poll...\n"));
+                    int cFds = poll(&PollFd, 1, cMillies == RT_INDEFINITE_WAIT ? -1 : (int)cMillies);
+                    if (cFds >= 1)
+                    {
+                        /* Linux & Darwin sets both POLLIN and POLLHUP when the pipe is
+                           broken and but no more data to read.  Google hints at NetBSD
+                           returning more sane values (POLLIN till no more data, then
+                           POLLHUP).  Solairs OTOH, doesn't ever seem to return POLLHUP. */
+                        fEvents = RTPOLL_EVT_READ;
+                        if (   (PollFd.revents & (POLLHUP | POLLERR))
+                            && !(PollFd.revents & POLLIN))
+                            fEvents = RTPOLL_EVT_ERROR;
+# if defined(RT_OS_SOLARIS)
+                        else if (PollFd.revents & POLLIN)
+# else
+                        else if ((PollFd.revents & (POLLIN | POLLHUP)) == (POLLIN | POLLHUP))
+# endif
+                        {
+                            /* Check if there is actually data available. */
+                            uint8_t bPeek;
+                            ssize_t rcRecv = recv(PollFd.fd, &bPeek, 1, MSG_DONTWAIT | MSG_PEEK);
+                            if (rcRecv <= 0)
+                                fEvents = RTPOLL_EVT_ERROR;
+                        }
+                        rc = VINF_SUCCESS;
+                    }
+                    else if (rc == 0)
+                        rc = VERR_TIMEOUT;
+                    else
+                        rc = RTErrConvertFromErrno(errno);
+                    Log(("RTLocalIpcSessionWaitForData: poll returns %u (rc=%d), revents=%#x\n", cFds, rc, PollFd.revents));
+#endif
+
+                    int rc2 = RTCritSectEnter(&pThis->CritSect);
+                    AssertRCBreakStmt(rc2, rc = RT_SUCCESS(rc) ? rc2 : rc);
+
+                    if (RT_SUCCESS(rc))
+                    {
+                        if (pThis->fCancelled)
+                            rc = VERR_CANCELLED;
+                        else if (fEvents & RTPOLL_EVT_ERROR)
+                            rc = VERR_BROKEN_PIPE;
+                    }
+                    else if (   rc == VERR_INTERRUPTED
+                             || rc == VERR_TRY_AGAIN)
+                    {
+                        /* Recalc cMillies. */
+                        if (cMsOriginalTimeout != RT_INDEFINITE_WAIT)
+                        {
+                            uint64_t cMsElapsed = RTTimeMilliTS() - msStart;
+                            cMillies = cMsElapsed >= cMsOriginalTimeout ? 0 : cMsOriginalTimeout - (RTMSINTERVAL)cMsElapsed;
+                        }
+                        continue;
+                    }
+                }
+                else
+                    rc = VERR_CANCELLED;
+                break;
+            }
+
+            pThis->hReadThread = NIL_RTTHREAD;
+        }
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+    return rc;
+}
+
+
+/**
+ * Get IPC session socket peer credentials.
+ *
+ * @returns IPRT status code.
+ * @param   hSession    IPC session handle.
+ * @param   pProcess    Where to return the remote peer's PID (can be NULL).
+ * @param   pUid        Where to return the remote peer's UID (can be NULL).
+ * @param   pGid        Where to return the remote peer's GID (can be NULL).
+ */
+static int rtLocalIpcSessionQueryUcred(RTLOCALIPCSESSION hSession, PRTPROCESS pProcess, PRTUID pUid, PRTGID pGid)
+{
+    PRTLOCALIPCSESSIONINT pThis = hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+#if defined(RT_OS_LINUX)
+    struct ucred PeerCred   = { (pid_t)NIL_RTPROCESS, (uid_t)NIL_RTUID, (gid_t)NIL_RTGID };
+    socklen_t    cbPeerCred = sizeof(PeerCred);
+
+    rtLocalIpcSessionRetain(pThis);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);;
+    if (RT_SUCCESS(rc))
+    {
+        if (getsockopt(RTSocketToNative(pThis->hSocket), SOL_SOCKET, SO_PEERCRED, &PeerCred, &cbPeerCred) >= 0)
+        {
+            if (pProcess)
+                *pProcess = PeerCred.pid;
+            if (pUid)
+                *pUid = PeerCred.uid;
+            if (pGid)
+                *pGid = PeerCred.gid;
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+
+        int rc2 = RTCritSectLeave(&pThis->CritSect);
+        AssertStmt(RT_SUCCESS(rc2), rc = RT_SUCCESS(rc) ? rc2 : rc);
+    }
+
+    rtLocalIpcSessionRelease(pThis);
+
+    return rc;
+
+#else
+    /** @todo Implement on other platforms too (mostly platform specific this).
+     *        Solaris: getpeerucred?  Darwin: LOCALPEERCRED or getpeereid? */
+    RT_NOREF(pProcess, pUid, pGid);
+    return VERR_NOT_SUPPORTED;
+#endif
+}
+
+
+RTDECL(int) RTLocalIpcSessionQueryProcess(RTLOCALIPCSESSION hSession, PRTPROCESS pProcess)
+{
+    return rtLocalIpcSessionQueryUcred(hSession, pProcess, NULL, NULL);
+}
+
+
+RTDECL(int) RTLocalIpcSessionQueryUserId(RTLOCALIPCSESSION hSession, PRTUID pUid)
+{
+    return rtLocalIpcSessionQueryUcred(hSession, NULL, pUid, NULL);
+}
+
+RTDECL(int) RTLocalIpcSessionQueryGroupId(RTLOCALIPCSESSION hSession, PRTGID pGid)
+{
+    return rtLocalIpcSessionQueryUcred(hSession, NULL, NULL, pGid);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/path-posix.cpp b/src/VBox/Runtime/r3/posix/path-posix.cpp
new file mode 100644
index 00000000..04462315
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/path-posix.cpp
@@ -0,0 +1,418 @@
+/* $Id: path-posix.cpp $ */
+/** @file
+ * IPRT - Path Manipulation, POSIX, Part 1.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <pwd.h>
+
+#include <iprt/path.h>
+#include <iprt/env.h>
+#include <iprt/assert.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/path.h"
+#include "internal/process.h"
+#include "internal/fs.h"
+
+
+
+RTDECL(int) RTPathReal(const char *pszPath, char *pszRealPath, size_t cchRealPath)
+{
+    /*
+     * Convert input.
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * On POSIX platforms the API doesn't take a length parameter, which makes it
+         * a little bit more work.
+         */
+        char szTmpPath[PATH_MAX + 1];
+        const char *psz = realpath(pszNativePath, szTmpPath);
+        if (psz)
+            rc = rtPathFromNativeCopy(pszRealPath, cchRealPath, szTmpPath, NULL);
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTPathReal(%p:{%s}, %p:{%s}, %u): returns %Rrc\n", pszPath, pszPath,
+             pszRealPath, RT_SUCCESS(rc) ? pszRealPath : "<failed>",  cchRealPath, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathSetMode(const char *pszPath, RTFMODE fMode)
+{
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+
+    int rc;
+    fMode = rtFsModeNormalize(fMode, pszPath, 0, 0);
+    if (rtFsModeIsValidPermissions(fMode))
+    {
+        char const *pszNativePath;
+        rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            if (chmod(pszNativePath, fMode & RTFS_UNIX_MASK) != 0)
+                rc = RTErrConvertFromErrno(errno);
+            rtPathFreeNative(pszNativePath, pszPath);
+        }
+    }
+    else
+    {
+        AssertMsgFailed(("Invalid file mode! %RTfmode\n", fMode));
+        rc = VERR_INVALID_FMODE;
+    }
+    return rc;
+}
+
+
+/**
+ * Checks if two files are the one and same file.
+ */
+static bool rtPathSame(const char *pszNativeSrc, const char *pszNativeDst)
+{
+    struct stat SrcStat;
+    if (lstat(pszNativeSrc, &SrcStat))
+        return false;
+    struct stat DstStat;
+    if (lstat(pszNativeDst, &DstStat))
+        return false;
+    Assert(SrcStat.st_dev && DstStat.st_dev);
+    Assert(SrcStat.st_ino && DstStat.st_ino);
+    if (    SrcStat.st_dev == DstStat.st_dev
+        &&  SrcStat.st_ino == DstStat.st_ino
+        &&  (SrcStat.st_mode & S_IFMT) == (DstStat.st_mode & S_IFMT))
+        return true;
+    return false;
+}
+
+
+/**
+ * Worker for RTPathRename, RTDirRename, RTFileRename.
+ *
+ * @returns IPRT status code.
+ * @param   pszSrc      The source path.
+ * @param   pszDst      The destination path.
+ * @param   fRename     The rename flags.
+ * @param   fFileType   The filetype. We use the RTFMODE filetypes here. If it's 0,
+ *                      anything goes. If it's RTFS_TYPE_DIRECTORY we'll check that the
+ *                      source is a directory. If Its RTFS_TYPE_FILE we'll check that it's
+ *                      not a directory (we are NOT checking whether it's a file).
+ */
+DECLHIDDEN(int) rtPathPosixRename(const char *pszSrc, const char *pszDst, unsigned fRename, RTFMODE fFileType)
+{
+    /*
+     * Convert the paths.
+     */
+    char const *pszNativeSrc;
+    int rc = rtPathToNative(&pszNativeSrc, pszSrc, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        char const *pszNativeDst;
+        rc = rtPathToNative(&pszNativeDst, pszDst, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Check that the source exists and that any types that's specified matches.
+             * We have to check this first to avoid getting errnous VERR_ALREADY_EXISTS
+             * errors from the next step.
+             *
+             * There are race conditions here (perhaps unlikely ones, but still), but I'm
+             * afraid there is little with can do to fix that.
+             */
+            struct stat SrcStat;
+            if (lstat(pszNativeSrc, &SrcStat))
+                rc = RTErrConvertFromErrno(errno);
+            else if (!fFileType)
+                rc = VINF_SUCCESS;
+            else if (RTFS_IS_DIRECTORY(fFileType))
+                rc = S_ISDIR(SrcStat.st_mode) ? VINF_SUCCESS : VERR_NOT_A_DIRECTORY;
+            else
+                rc = S_ISDIR(SrcStat.st_mode) ? VERR_IS_A_DIRECTORY : VINF_SUCCESS;
+            if (RT_SUCCESS(rc))
+            {
+                bool fSameFile = false;
+
+                /*
+                 * Check if the target exists, rename is rather destructive.
+                 * We'll have to make sure we don't overwrite the source!
+                 * Another race condition btw.
+                 */
+                struct stat DstStat;
+                if (lstat(pszNativeDst, &DstStat))
+                    rc = errno == ENOENT ? VINF_SUCCESS : RTErrConvertFromErrno(errno);
+                else
+                {
+                    Assert(SrcStat.st_dev && DstStat.st_dev);
+                    Assert(SrcStat.st_ino && DstStat.st_ino);
+                    if (    SrcStat.st_dev == DstStat.st_dev
+                        &&  SrcStat.st_ino == DstStat.st_ino
+                        &&  (SrcStat.st_mode & S_IFMT) == (DstStat.st_mode & S_IFMT))
+                    {
+                        /*
+                         * It's likely that we're talking about the same file here.
+                         * We should probably check paths or whatever, but for now this'll have to be enough.
+                         */
+                        fSameFile = true;
+                    }
+                    if (fSameFile)
+                        rc = VINF_SUCCESS;
+                    else if (S_ISDIR(DstStat.st_mode) || !(fRename & RTPATHRENAME_FLAGS_REPLACE))
+                        rc = VERR_ALREADY_EXISTS;
+                    else
+                        rc = VINF_SUCCESS;
+
+                }
+                if (RT_SUCCESS(rc))
+                {
+                    if (!rename(pszNativeSrc, pszNativeDst))
+                        rc = VINF_SUCCESS;
+                    else if (   (fRename & RTPATHRENAME_FLAGS_REPLACE)
+                             && (errno == ENOTDIR || errno == EEXIST))
+                    {
+                        /*
+                         * Check that the destination isn't a directory.
+                         * Yet another race condition.
+                         */
+                        if (rtPathSame(pszNativeSrc, pszNativeDst))
+                        {
+                            rc = VINF_SUCCESS;
+                            Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): appears to be the same file... (errno=%d)\n",
+                                 pszSrc, pszDst, fRename, fFileType, errno));
+                        }
+                        else
+                        {
+                            if (lstat(pszNativeDst, &DstStat))
+                                rc = errno != ENOENT ? RTErrConvertFromErrno(errno) : VINF_SUCCESS;
+                            else if (S_ISDIR(DstStat.st_mode))
+                                rc = VERR_ALREADY_EXISTS;
+                            else
+                                rc = VINF_SUCCESS;
+                            if (RT_SUCCESS(rc))
+                            {
+                                if (!unlink(pszNativeDst))
+                                {
+                                    if (!rename(pszNativeSrc, pszNativeDst))
+                                        rc = VINF_SUCCESS;
+                                    else
+                                    {
+                                        rc = RTErrConvertFromErrno(errno);
+                                        Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): rename failed rc=%Rrc errno=%d\n",
+                                             pszSrc, pszDst, fRename, fFileType, rc, errno));
+                                    }
+                                }
+                                else
+                                {
+                                    rc = RTErrConvertFromErrno(errno);
+                                    Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): failed to unlink dst rc=%Rrc errno=%d\n",
+                                         pszSrc, pszDst, fRename, fFileType, rc, errno));
+                                }
+                            }
+                            else
+                                Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): dst !dir check failed rc=%Rrc\n",
+                                     pszSrc, pszDst, fRename, fFileType, rc));
+                        }
+                    }
+                    else
+                    {
+                        rc = RTErrConvertFromErrno(errno);
+                        if (errno == ENOTDIR)
+                            rc = VERR_ALREADY_EXISTS; /* unless somebody is racing us, this is the right interpretation */
+                        Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): rename failed rc=%Rrc errno=%d\n",
+                             pszSrc, pszDst, fRename, fFileType, rc, errno));
+                    }
+                }
+                else
+                    Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): destination check failed rc=%Rrc errno=%d\n",
+                         pszSrc, pszDst, fRename, fFileType, rc, errno));
+            }
+            else
+                Log(("rtPathRename('%s', '%s', %#x ,%RTfmode): source type check failed rc=%Rrc errno=%d\n",
+                     pszSrc, pszDst, fRename, fFileType, rc, errno));
+
+            rtPathFreeNative(pszNativeDst, pszDst);
+        }
+        rtPathFreeNative(pszNativeSrc, pszSrc);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(*pszSrc, ("%p\n", pszSrc), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(*pszDst, ("%p\n", pszDst), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Hand it to the worker.
+     */
+    int rc = rtPathPosixRename(pszSrc, pszDst, fRename, 0);
+
+    Log(("RTPathRename(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n", pszSrc, pszSrc, pszDst, pszDst, fRename, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathUnlink(const char *pszPath, uint32_t fUnlink)
+{
+    RT_NOREF_PV(pszPath); RT_NOREF_PV(fUnlink);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(bool) RTPathExists(const char *pszPath)
+{
+    return RTPathExistsEx(pszPath, RTPATH_F_FOLLOW_LINK);
+}
+
+
+RTDECL(bool) RTPathExistsEx(const char *pszPath, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, false);
+    AssertReturn(*pszPath, false);
+    Assert(RTPATH_F_IS_VALID(fFlags, 0));
+
+    /*
+     * Convert the path and check if it exists using stat().
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat Stat;
+        if (fFlags & RTPATH_F_FOLLOW_LINK)
+            rc = stat(pszNativePath, &Stat);
+        else
+            rc = lstat(pszNativePath, &Stat);
+        if (!rc)
+            rc = VINF_SUCCESS;
+        else
+            rc = VERR_GENERAL_FAILURE;
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+    return RT_SUCCESS(rc);
+}
+
+
+RTDECL(int)  RTPathGetCurrent(char *pszPath, size_t cchPath)
+{
+    /*
+     * Try with a reasonably sized buffer first.
+     */
+    char szNativeCurDir[RTPATH_MAX];
+    if (getcwd(szNativeCurDir, sizeof(szNativeCurDir)) != NULL)
+        return rtPathFromNativeCopy(pszPath, cchPath, szNativeCurDir, NULL);
+
+    /*
+     * Retry a few times with really big buffers if we failed because CWD is unreasonably long.
+     */
+    int iErr = errno;
+    if (iErr != ERANGE)
+        return RTErrConvertFromErrno(iErr);
+
+    size_t cbNativeTmp = RTPATH_BIG_MAX;
+    for (;;)
+    {
+        char *pszNativeTmp = (char *)RTMemTmpAlloc(cbNativeTmp);
+        if (!pszNativeTmp)
+            return VERR_NO_TMP_MEMORY;
+        if (getcwd(pszNativeTmp, cbNativeTmp) != NULL)
+        {
+            int rc = rtPathFromNativeCopy(pszPath, cchPath, pszNativeTmp, NULL);
+            RTMemTmpFree(pszNativeTmp);
+            return rc;
+        }
+        iErr = errno;
+        RTMemTmpFree(pszNativeTmp);
+        if (iErr != ERANGE)
+            return RTErrConvertFromErrno(iErr);
+
+        cbNativeTmp += RTPATH_BIG_MAX;
+        if (cbNativeTmp > RTPATH_BIG_MAX * 4)
+            return VERR_FILENAME_TOO_LONG;
+    }
+}
+
+
+RTDECL(int) RTPathSetCurrent(const char *pszPath)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * Change the directory.
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (chdir(pszNativePath))
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/path2-posix.cpp b/src/VBox/Runtime/r3/posix/path2-posix.cpp
new file mode 100644
index 00000000..9af9512f
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/path2-posix.cpp
@@ -0,0 +1,316 @@
+/* $Id: path2-posix.cpp $ */
+/** @file
+ * IPRT - Path Manipulation, POSIX, Part 2 - RTPathQueryInfo.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include <stdlib.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#include <iprt/path.h>
+#include <iprt/env.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/path.h"
+#include "internal/process.h"
+#include "internal/fs.h"
+
+
+RTR3DECL(int) RTPathQueryInfo(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    return RTPathQueryInfoEx(pszPath, pObjInfo, enmAdditionalAttribs, RTPATH_F_ON_LINK);
+}
+
+
+RTR3DECL(int) RTPathQueryInfoEx(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pObjInfo, VERR_INVALID_POINTER);
+    AssertMsgReturn(    enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING
+                    &&  enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                    ("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs),
+                    VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the filename.
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat Stat;
+        if (fFlags & RTPATH_F_FOLLOW_LINK)
+            rc = stat(pszNativePath, &Stat);
+        else
+            rc = lstat(pszNativePath, &Stat); /** @todo how doesn't have lstat again? */
+        if (!rc)
+        {
+            rtFsConvertStatToObjInfo(pObjInfo, &Stat, pszPath, 0);
+            switch (enmAdditionalAttribs)
+            {
+                case RTFSOBJATTRADD_NOTHING:
+                case RTFSOBJATTRADD_UNIX:
+                    Assert(pObjInfo->Attr.enmAdditional == RTFSOBJATTRADD_UNIX);
+                    break;
+
+                case RTFSOBJATTRADD_UNIX_OWNER:
+                    rtFsObjInfoAttrSetUnixOwner(pObjInfo, Stat.st_uid);
+                    break;
+
+                case RTFSOBJATTRADD_UNIX_GROUP:
+                    rtFsObjInfoAttrSetUnixGroup(pObjInfo, Stat.st_gid);
+                    break;
+
+                case RTFSOBJATTRADD_EASIZE:
+                    /** @todo Use SGI extended attribute interface to query EA info. */
+                    pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+                    pObjInfo->Attr.u.EASize.cb            = 0;
+                    break;
+
+                default:
+                    AssertMsgFailed(("Impossible!\n"));
+                    return VERR_INTERNAL_ERROR;
+            }
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTPathQueryInfoEx(%p:{%s}, pObjInfo=%p, %d): returns %Rrc\n",
+             pszPath, pszPath, pObjInfo, enmAdditionalAttribs, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathSetTimes(const char *pszPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                             PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
+{
+    return RTPathSetTimesEx(pszPath, pAccessTime, pModificationTime, pChangeTime, pBirthTime, RTPATH_F_ON_LINK);
+}
+
+
+RTR3DECL(int) RTPathSetTimesEx(const char *pszPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                               PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pAccessTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pModificationTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pChangeTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pBirthTime, VERR_INVALID_POINTER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the paths.
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        RTFSOBJINFO ObjInfo;
+
+        /*
+         * If it's a no-op, we'll only verify the existance of the file.
+         */
+        if (!pAccessTime && !pModificationTime)
+            rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_NOTHING, fFlags);
+        else
+        {
+            /*
+             * Convert the input to timeval, getting the missing one if necessary,
+             * and call the API which does the change.
+             */
+            struct timeval aTimevals[2];
+            if (pAccessTime && pModificationTime)
+            {
+                RTTimeSpecGetTimeval(pAccessTime,       &aTimevals[0]);
+                RTTimeSpecGetTimeval(pModificationTime, &aTimevals[1]);
+            }
+            else
+            {
+                rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_UNIX, fFlags);
+                if (RT_SUCCESS(rc))
+                {
+                    RTTimeSpecGetTimeval(pAccessTime        ? pAccessTime       : &ObjInfo.AccessTime,       &aTimevals[0]);
+                    RTTimeSpecGetTimeval(pModificationTime  ? pModificationTime : &ObjInfo.ModificationTime, &aTimevals[1]);
+                }
+                else
+                    Log(("RTPathSetTimes('%s',%p,%p,,): RTPathQueryInfo failed with %Rrc\n",
+                         pszPath, pAccessTime, pModificationTime, rc));
+            }
+            if (RT_SUCCESS(rc))
+            {
+                if (fFlags & RTPATH_F_FOLLOW_LINK)
+                {
+                    if (utimes(pszNativePath, aTimevals))
+                        rc = RTErrConvertFromErrno(errno);
+                }
+#if (defined(RT_OS_DARWIN) && MAC_OS_X_VERSION_MIN_REQUIRED >= 1050) \
+ || defined(RT_OS_FREEBSD) \
+ || defined(RT_OS_LINUX) \
+ || defined(RT_OS_OS2) /** @todo who really has lutimes? */
+                else
+                {
+                    if (lutimes(pszNativePath, aTimevals))
+                    {
+                        /* If lutimes is not supported (e.g. linux < 2.6.22), try fall back on utimes: */
+                        if (errno != ENOSYS)
+                            rc = RTErrConvertFromErrno(errno);
+                        else
+                        {
+                            if (pAccessTime && pModificationTime)
+                                rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_UNIX, fFlags);
+                            if (RT_SUCCESS(rc) && !RTFS_IS_SYMLINK(ObjInfo.Attr.fMode))
+                            {
+                                if (utimes(pszNativePath, aTimevals))
+                                    rc = RTErrConvertFromErrno(errno);
+                            }
+                            else
+                                rc = VERR_NOT_SUPPORTED;
+                        }
+                    }
+                }
+#else
+                else
+                {
+                    if (pAccessTime && pModificationTime)
+                        rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_UNIX, fFlags);
+                    if (RT_SUCCESS(rc) && RTFS_IS_SYMLINK(ObjInfo.Attr.fMode))
+                        rc = VERR_NS_SYMLINK_SET_TIME;
+                    else if (RT_SUCCESS(rc))
+                    {
+                        if (utimes(pszNativePath, aTimevals))
+                            rc = RTErrConvertFromErrno(errno);
+                    }
+                }
+#endif
+                if (RT_FAILURE(rc))
+                    Log(("RTPathSetTimes('%s',%p,%p,,): failed with %Rrc and errno=%d\n",
+                         pszPath, pAccessTime, pModificationTime, rc, errno));
+            }
+        }
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTPathSetTimes(%p:{%s}, %p:{%RDtimespec}, %p:{%RDtimespec}, %p:{%RDtimespec}, %p:{%RDtimespec}): return %Rrc\n",
+             pszPath, pszPath, pAccessTime, pAccessTime, pModificationTime, pModificationTime,
+             pChangeTime, pChangeTime, pBirthTime, pBirthTime, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathSetOwner(const char *pszPath, uint32_t uid, uint32_t gid)
+{
+    return RTPathSetOwnerEx(pszPath, uid, gid, RTPATH_F_ON_LINK);
+}
+
+
+RTR3DECL(int) RTPathSetOwnerEx(const char *pszPath, uint32_t uid, uint32_t gid, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+    uid_t uidNative = uid != NIL_RTUID ? (uid_t)uid : (uid_t)-1;
+    AssertReturn(uid == uidNative, VERR_INVALID_PARAMETER);
+    gid_t gidNative = gid != NIL_RTGID ? (gid_t)gid : (uid_t)-1;
+    AssertReturn(gid == gidNative, VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the path.
+     */
+    char const *pszNativePath;
+    int rc = rtPathToNative(&pszNativePath, pszPath, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (fFlags & RTPATH_F_FOLLOW_LINK)
+        {
+            if (chown(pszNativePath, uidNative, gidNative))
+                rc = RTErrConvertFromErrno(errno);
+        }
+#if 1
+        else
+        {
+            if (lchown(pszNativePath, uidNative, gidNative))
+                rc = RTErrConvertFromErrno(errno);
+        }
+#else
+        else
+        {
+            RTFSOBJINFO ObjInfo;
+            rc = RTPathQueryInfoEx(pszPath, &ObjInfo, RTFSOBJATTRADD_UNIX, fFlags);
+            if (RT_SUCCESS(rc) && RTFS_IS_SYMLINK(ObjInfo.Attr.fMode))
+                rc = VERR_NS_SYMLINK_CHANGE_OWNER;
+            else if (RT_SUCCESS(rc))
+            {
+                if (lchown(pszNativePath, uidNative, gidNative))
+                    rc = RTErrConvertFromErrno(errno);
+            }
+        }
+#endif
+        if (RT_FAILURE(rc))
+            Log(("RTPathSetOwnerEx('%s',%d,%d): failed with %Rrc and errno=%d\n",
+                 pszPath, uid, gid, rc, errno));
+
+        rtPathFreeNative(pszNativePath, pszPath);
+    }
+
+    LogFlow(("RTPathSetOwnerEx(%p:{%s}, uid=%d, gid=%d): return %Rrc\n",
+             pszPath, pszPath, uid, gid, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/pathhost-posix.cpp b/src/VBox/Runtime/r3/posix/pathhost-posix.cpp
new file mode 100644
index 00000000..b0c4fe46
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/pathhost-posix.cpp
@@ -0,0 +1,294 @@
+/* $Id: pathhost-posix.cpp $ */
+/** @file
+ * IPRT - Path Conversions, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include "internal/iprt.h"
+#include "internal/path.h"
+#include "internal/string.h"
+#include "internal/thread.h"
+
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include <iprt/once.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Initialize once object. */
+static RTONCE       g_OnceInitPathConv = RTONCE_INITIALIZER;
+/** If set, then we can pass UTF-8 thru directly. */
+static bool         g_fPassthruUtf8    = false;
+/** The UTF-8 to FS iconv cache entry. */
+static RTSTRICONV   g_enmUtf8ToFsIdx   = RTSTRICONV_UTF8_TO_LOCALE;
+/** The FS to UTF-8 iconv cache entry. */
+static RTSTRICONV   g_enmFsToUtf8Idx   = RTSTRICONV_LOCALE_TO_UTF8;
+/** The codeset we're using. */
+static char         g_szFsCodeset[32];
+
+
+/**
+ * Do a case insensitive compare where the 2nd string is known and can be case
+ * folded when writing the code.
+ *
+ * @returns see strcmp.
+ * @param   pszStr1             The string to compare against pszLower and
+ *                              pszUpper.
+ * @param   pszUpper            The upper case edition of the 2nd string.
+ * @param   pszLower            The lower case edition of the 2nd string.
+ */
+static int rtPathStrICmp(const char *pszStr1, const char *pszUpper, const char *pszLower)
+{
+    Assert(strlen(pszLower) == strlen(pszUpper));
+    for (;;)
+    {
+        char ch1      = *pszStr1++;
+        char ch2Upper = *pszUpper++;
+        char ch2Lower = *pszLower++;
+        if (   ch1 != ch2Upper
+            && ch1 != ch2Lower)
+            return ch1 < ch2Upper ? -1 : 1;
+        if (!ch1)
+            return 0;
+    }
+}
+
+/**
+ * Is the specified codeset something we can treat as UTF-8.
+ *
+ * @returns true if we can do UTF-8 passthru, false if not.
+ * @param   pszCodeset          The codeset in question.
+ */
+static bool rtPathConvInitIsUtf8(const char *pszCodeset)
+{
+    /* Paranoia. */
+    if (!pszCodeset)
+        return false;
+
+    /*
+     * Avoid RTStrICmp at this point.
+     */
+    static struct
+    {
+        const char *pszUpper;
+        const char *pszLower;
+    } const s_aUtf8Compatible[] =
+    {
+        /* The default locale. */
+        { "C"                   , "c"                   },
+        { "POSIX"               , "posix"               },
+        /* 7-bit ASCII. */
+        { "ANSI_X3.4-1968"      , "ansi_x3.4-1968"      },
+        { "ANSI_X3.4-1986"      , "ansi_x3.4-1986"      },
+        { "US-ASCII"            , "us-ascii"            },
+        { "ISO646-US"           , "iso646-us"           },
+        { "ISO_646.IRV:1991"    , "iso_646.irv:1991"    },
+        { "ISO-IR-6"            , "iso-ir-6"            },
+        { "IBM367"              , "ibm367"              },
+        /* UTF-8 */
+        { "UTF-8"               , "utf-8"               },
+        { "UTF8"                , "utf8"                },
+        { "ISO-10646/UTF-8"     , "iso-10646/utf-8"     },
+        { "ISO-10646/UTF8"      , "iso-10646/utf8"      }
+    };
+
+    for (size_t i = 0; i < RT_ELEMENTS(s_aUtf8Compatible); i++)
+        if (!rtPathStrICmp(pszCodeset, s_aUtf8Compatible[i].pszUpper, s_aUtf8Compatible[i].pszLower))
+            return true;
+
+    return false;
+}
+
+
+/**
+ * Init once for the path conversion code.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser1             Unused.
+ * @param   pvUser2             Unused.
+ */
+static DECLCALLBACK(int32_t) rtPathConvInitOnce(void *pvUser)
+{
+    /*
+     * Read the environment variable, no mercy on misconfigs here except that
+     * empty values are quietly ignored.  (We use a temp buffer for stripping.)
+     */
+    char *pszEnvValue = NULL;
+    char  szEnvValue[sizeof(g_szFsCodeset)];
+    int rc = RTEnvGetEx(RTENV_DEFAULT, RTPATH_CODESET_ENV_VAR, szEnvValue, sizeof(szEnvValue), NULL);
+    if (rc != VERR_ENV_VAR_NOT_FOUND && RT_FAILURE(rc))
+        return rc;
+    if (RT_SUCCESS(rc))
+        pszEnvValue = RTStrStrip(szEnvValue);
+
+    if (pszEnvValue && *pszEnvValue)
+    {
+        g_fPassthruUtf8  = rtPathConvInitIsUtf8(pszEnvValue);
+        g_enmFsToUtf8Idx = RTSTRICONV_FS_TO_UTF8;
+        g_enmUtf8ToFsIdx = RTSTRICONV_UTF8_TO_FS;
+        strcpy(g_szFsCodeset, pszEnvValue);
+    }
+    else
+    {
+        const char *pszCodeset = rtStrGetLocaleCodeset();
+        size_t      cchCodeset = pszCodeset ? strlen(pszCodeset) : sizeof(g_szFsCodeset);
+        if (cchCodeset >= sizeof(g_szFsCodeset))
+            /* This shouldn't happen, but we'll manage. */
+            g_szFsCodeset[0] = '\0';
+        else
+        {
+            memcpy(g_szFsCodeset, pszCodeset, cchCodeset + 1);
+            pszCodeset = g_szFsCodeset;
+        }
+        g_fPassthruUtf8  = rtPathConvInitIsUtf8(pszCodeset);
+        g_enmFsToUtf8Idx = RTSTRICONV_LOCALE_TO_UTF8;
+        g_enmUtf8ToFsIdx = RTSTRICONV_UTF8_TO_LOCALE;
+    }
+
+    NOREF(pvUser);
+    return VINF_SUCCESS;
+}
+
+
+int rtPathToNative(char const **ppszNativePath, const char *pszPath, const char *pszBasePath)
+{
+    *ppszNativePath = NULL;
+
+    int rc = RTOnce(&g_OnceInitPathConv, rtPathConvInitOnce, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (g_fPassthruUtf8 || !*pszPath)
+            *ppszNativePath = pszPath;
+        else
+            rc = rtStrConvert(pszPath, strlen(pszPath), "UTF-8",
+                              (char **)ppszNativePath, 0, g_szFsCodeset,
+                              2, g_enmUtf8ToFsIdx);
+    }
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
+
+void rtPathFreeNative(char const *pszNativePath, const char *pszPath)
+{
+    if (    pszNativePath != pszPath
+        &&  pszNativePath)
+        RTStrFree((char *)pszNativePath);
+}
+
+
+int rtPathFromNative(const char **ppszPath, const char *pszNativePath, const char *pszBasePath)
+{
+    *ppszPath = NULL;
+
+    int rc = RTOnce(&g_OnceInitPathConv, rtPathConvInitOnce, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (g_fPassthruUtf8 || !*pszNativePath)
+        {
+            size_t cCpsIgnored;
+            size_t cchNativePath;
+            rc = rtUtf8Length(pszNativePath, RTSTR_MAX, &cCpsIgnored, &cchNativePath);
+            if (RT_SUCCESS(rc))
+            {
+                char *pszPath;
+                *ppszPath = pszPath = RTStrAlloc(cchNativePath + 1);
+                if (pszPath)
+                    memcpy(pszPath, pszNativePath, cchNativePath + 1);
+                else
+                    rc = VERR_NO_STR_MEMORY;
+            }
+        }
+        else
+            rc = rtStrConvert(pszNativePath, strlen(pszNativePath), g_szFsCodeset,
+                              (char **)ppszPath, 0, "UTF-8",
+                              2, g_enmFsToUtf8Idx);
+    }
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
+
+void rtPathFreeIprt(const char *pszPath, const char *pszNativePath)
+{
+    if (   pszPath != pszNativePath
+        && pszPath)
+        RTStrFree((char *)pszPath);
+}
+
+
+int rtPathFromNativeCopy(char *pszPath, size_t cbPath, const char *pszNativePath, const char *pszBasePath)
+{
+    int rc = RTOnce(&g_OnceInitPathConv, rtPathConvInitOnce, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (g_fPassthruUtf8 || !*pszNativePath)
+            rc = RTStrCopy(pszPath, cbPath, pszNativePath);
+        else if (cbPath)
+            rc = rtStrConvert(pszNativePath, strlen(pszNativePath), g_szFsCodeset,
+                              &pszPath, cbPath, "UTF-8",
+                              2, g_enmFsToUtf8Idx);
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
+
+int rtPathFromNativeDup(char **ppszPath, const char *pszNativePath, const char *pszBasePath)
+{
+    int rc = RTOnce(&g_OnceInitPathConv, rtPathConvInitOnce, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (g_fPassthruUtf8 || !*pszNativePath)
+            rc = RTStrDupEx(ppszPath, pszNativePath);
+        else
+            rc = rtStrConvert(pszNativePath, strlen(pszNativePath), g_szFsCodeset,
+                              ppszPath, 0, "UTF-8",
+                              2, g_enmFsToUtf8Idx);
+    }
+
+    NOREF(pszBasePath); /* We don't query the FS for codeset preferences. */
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/pipe-posix.cpp b/src/VBox/Runtime/r3/posix/pipe-posix.cpp
new file mode 100644
index 00000000..dc673bd3
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/pipe-posix.cpp
@@ -0,0 +1,754 @@
+/* $Id: pipe-posix.cpp $ */
+/** @file
+ * IPRT - Anonymous Pipes, POSIX Implementation.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/pipe.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/poll.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include "internal/magics.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/poll.h>
+#include <sys/stat.h>
+#include <signal.h>
+#ifdef RT_OS_LINUX
+# include <sys/syscall.h>
+#endif
+#ifdef RT_OS_SOLARIS
+# include <sys/filio.h>
+#endif
+
+#include "internal/pipe.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct RTPIPEINTERNAL
+{
+    /** Magic value (RTPIPE_MAGIC). */
+    uint32_t            u32Magic;
+    /** The file descriptor. */
+    int                 fd;
+    /** Set if this is the read end, clear if it's the write end. */
+    bool                fRead;
+    /** RTPipeFromNative: Leave it open on RTPipeClose. */
+    bool                fLeaveOpen;
+    /** Atomically operated state variable.
+     *
+     *  - Bits 0 thru 29 - Users of the new mode.
+     *  - Bit 30 - The pipe mode, set indicates blocking.
+     *  - Bit 31 - Set when we're switching the mode.
+     */
+    uint32_t volatile   u32State;
+} RTPIPEINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @name RTPIPEINTERNAL::u32State defines
+ * @{ */
+#define RTPIPE_POSIX_BLOCKING           UINT32_C(0x40000000)
+#define RTPIPE_POSIX_SWITCHING          UINT32_C(0x80000000)
+#define RTPIPE_POSIX_SWITCHING_BIT      31
+#define RTPIPE_POSIX_USERS_MASK         UINT32_C(0x3fffffff)
+/** @} */
+
+
+
+/**
+ * Wrapper for calling pipe2() or pipe().
+ *
+ * When using pipe2() the returned handles are marked close-on-exec and does
+ * not risk racing process creation calls on other threads.
+ *
+ * @returns See pipe().
+ * @param   paFds               See pipe().
+ * @param   piNewPipeSyscall    Where to cache which call we should used. -1 if
+ *                              pipe(), 1 if pipe2(), 0 if not yet decided.
+ */
+static int my_pipe_wrapper(int *paFds, int *piNewPipeSyscall)
+{
+    if (*piNewPipeSyscall >= 0)
+    {
+#if defined(RT_OS_LINUX) && defined(__NR_pipe2) && defined(O_CLOEXEC)
+        long rc = syscall(__NR_pipe2, paFds, O_CLOEXEC);
+        if (rc >= 0)
+        {
+            if (*piNewPipeSyscall == 0)
+                *piNewPipeSyscall = 1;
+            return (int)rc;
+        }
+#endif
+        *piNewPipeSyscall = -1;
+    }
+
+    return pipe(paFds);
+}
+
+
+RTDECL(int)  RTPipeCreate(PRTPIPE phPipeRead, PRTPIPE phPipeWrite, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipeRead, VERR_INVALID_POINTER);
+    AssertPtrReturn(phPipeWrite, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_C_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Create the pipe and clear/set the close-on-exec flag as required.
+     */
+    int aFds[2] = {-1, -1};
+    static int s_iNewPipeSyscall = 0;
+    if (my_pipe_wrapper(aFds, &s_iNewPipeSyscall))
+        return RTErrConvertFromErrno(errno);
+
+    int rc = VINF_SUCCESS;
+    if (s_iNewPipeSyscall > 0)
+    {
+        /* created with close-on-exec set. */
+        if (fFlags & RTPIPE_C_INHERIT_READ)
+        {
+            if (fcntl(aFds[0], F_SETFD, 0))
+                rc = RTErrConvertFromErrno(errno);
+        }
+
+        if (fFlags & RTPIPE_C_INHERIT_WRITE)
+        {
+            if (fcntl(aFds[1], F_SETFD, 0))
+                rc = RTErrConvertFromErrno(errno);
+        }
+    }
+    else
+    {
+        /* created with close-on-exec cleared. */
+        if (!(fFlags & RTPIPE_C_INHERIT_READ))
+        {
+            if (fcntl(aFds[0], F_SETFD, FD_CLOEXEC))
+                rc = RTErrConvertFromErrno(errno);
+        }
+
+        if (!(fFlags & RTPIPE_C_INHERIT_WRITE))
+        {
+            if (fcntl(aFds[1], F_SETFD, FD_CLOEXEC))
+                rc = RTErrConvertFromErrno(errno);
+        }
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Create the two handles.
+         */
+        RTPIPEINTERNAL *pThisR = (RTPIPEINTERNAL *)RTMemAlloc(sizeof(RTPIPEINTERNAL));
+        if (pThisR)
+        {
+            RTPIPEINTERNAL *pThisW = (RTPIPEINTERNAL *)RTMemAlloc(sizeof(RTPIPEINTERNAL));
+            if (pThisW)
+            {
+                pThisR->u32Magic    = RTPIPE_MAGIC;
+                pThisW->u32Magic    = RTPIPE_MAGIC;
+                pThisR->fd          = aFds[0];
+                pThisW->fd          = aFds[1];
+                pThisR->fRead       = true;
+                pThisW->fRead       = false;
+                pThisR->fLeaveOpen  = false;
+                pThisW->fLeaveOpen  = false;
+                pThisR->u32State    = RTPIPE_POSIX_BLOCKING;
+                pThisW->u32State    = RTPIPE_POSIX_BLOCKING;
+
+                *phPipeRead  = pThisR;
+                *phPipeWrite = pThisW;
+
+                /*
+                 * Before we leave, make sure to shut up SIGPIPE.
+                 */
+                signal(SIGPIPE, SIG_IGN);
+                return VINF_SUCCESS;
+            }
+
+            RTMemFree(pThisR);
+            rc = VERR_NO_MEMORY;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    close(aFds[0]);
+    close(aFds[1]);
+    return rc;
+}
+
+
+RTDECL(int)  RTPipeCloseEx(RTPIPE hPipe, bool fLeaveOpen)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    if (pThis == NIL_RTPIPE)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTPIPE_MAGIC, RTPIPE_MAGIC), VERR_INVALID_HANDLE);
+
+    int fd = pThis->fd;
+    pThis->fd = -1;
+    if (!fLeaveOpen && !pThis->fLeaveOpen)
+        close(fd);
+
+    if (ASMAtomicReadU32(&pThis->u32State) & RTPIPE_POSIX_USERS_MASK)
+    {
+        AssertFailed();
+        RTThreadSleep(1);
+    }
+
+    RTMemFree(pThis);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTPipeClose(RTPIPE hPipe)
+{
+    return RTPipeCloseEx(hPipe, false /*fLeaveOpen*/);
+}
+
+
+RTDECL(int)  RTPipeFromNative(PRTPIPE phPipe, RTHCINTPTR hNativePipe, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipe, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_N_VALID_MASK_FN), VERR_INVALID_PARAMETER);
+    AssertReturn(!!(fFlags & RTPIPE_N_READ) != !!(fFlags & RTPIPE_N_WRITE), VERR_INVALID_PARAMETER);
+
+    /*
+     * Get and validate the pipe handle info.
+     */
+    int hNative = (int)hNativePipe;
+    struct stat st;
+    AssertReturn(fstat(hNative, &st) == 0, RTErrConvertFromErrno(errno));
+    AssertMsgReturn(S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode), ("%#x (%o)\n", st.st_mode, st.st_mode), VERR_INVALID_HANDLE);
+
+    int fFd = fcntl(hNative, F_GETFL, 0);
+    AssertReturn(fFd != -1, VERR_INVALID_HANDLE);
+    AssertMsgReturn(   (fFd & O_ACCMODE) == (fFlags & RTPIPE_N_READ ? O_RDONLY : O_WRONLY)
+                    || (fFd & O_ACCMODE) == O_RDWR /* Solaris creates bi-directional pipes. */
+                    , ("%#x\n", fFd), VERR_INVALID_HANDLE);
+
+    /*
+     * Create the handle.
+     */
+    RTPIPEINTERNAL *pThis = (RTPIPEINTERNAL *)RTMemAlloc(sizeof(RTPIPEINTERNAL));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+
+    pThis->u32Magic   = RTPIPE_MAGIC;
+    pThis->fd         = hNative;
+    pThis->fRead      = RT_BOOL(fFlags & RTPIPE_N_READ);
+    pThis->fLeaveOpen = RT_BOOL(fFlags & RTPIPE_N_LEAVE_OPEN);
+    pThis->u32State   = fFd & O_NONBLOCK ? 0 : RTPIPE_POSIX_BLOCKING;
+
+    /*
+     * Fix up inheritability and shut up SIGPIPE and we're done.
+     */
+    if (fcntl(hNative, F_SETFD, fFlags & RTPIPE_N_INHERIT ? 0 : FD_CLOEXEC) == 0)
+    {
+        signal(SIGPIPE, SIG_IGN);
+        *phPipe = pThis;
+        return VINF_SUCCESS;
+    }
+
+    int rc = RTErrConvertFromErrno(errno);
+    RTMemFree(pThis);
+    return rc;
+}
+
+
+RTDECL(RTHCINTPTR) RTPipeToNative(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, -1);
+
+    return pThis->fd;
+}
+
+
+/**
+ * Prepare blocking mode.
+ *
+ * @returns VINF_SUCCESS
+ * @retval  VERR_WRONG_ORDER
+ * @retval  VERR_INTERNAL_ERROR_4
+ *
+ * @param   pThis               The pipe handle.
+ */
+static int rtPipeTryBlocking(RTPIPEINTERNAL *pThis)
+{
+    /*
+     * Update the state.
+     */
+    for (;;)
+    {
+        uint32_t        u32State    = ASMAtomicReadU32(&pThis->u32State);
+        uint32_t const  u32StateOld = u32State;
+        uint32_t const  cUsers      = (u32State & RTPIPE_POSIX_USERS_MASK);
+
+        if (u32State & RTPIPE_POSIX_BLOCKING)
+        {
+            AssertReturn(cUsers < RTPIPE_POSIX_USERS_MASK / 2, VERR_INTERNAL_ERROR_4);
+            u32State &= ~RTPIPE_POSIX_USERS_MASK;
+            u32State |= cUsers + 1;
+            if (ASMAtomicCmpXchgU32(&pThis->u32State, u32State, u32StateOld))
+            {
+                if (u32State & RTPIPE_POSIX_SWITCHING)
+                    break;
+                return VINF_SUCCESS;
+            }
+        }
+        else if (cUsers == 0)
+        {
+            u32State = 1 | RTPIPE_POSIX_SWITCHING | RTPIPE_POSIX_BLOCKING;
+            if (ASMAtomicCmpXchgU32(&pThis->u32State, u32State, u32StateOld))
+                break;
+        }
+        else
+            return VERR_WRONG_ORDER;
+        ASMNopPause();
+    }
+
+    /*
+     * Do the switching.
+     */
+    int fFlags = fcntl(pThis->fd, F_GETFL, 0);
+    if (fFlags != -1)
+    {
+        if (    !(fFlags & O_NONBLOCK)
+            ||  fcntl(pThis->fd, F_SETFL, fFlags & ~O_NONBLOCK) != -1)
+        {
+            ASMAtomicBitClear(&pThis->u32State, RTPIPE_POSIX_SWITCHING_BIT);
+            return VINF_SUCCESS;
+        }
+    }
+
+    ASMAtomicDecU32(&pThis->u32State);
+    return RTErrConvertFromErrno(errno);
+}
+
+
+/**
+ * Prepare non-blocking mode.
+ *
+ * @returns VINF_SUCCESS
+ * @retval  VERR_WRONG_ORDER
+ * @retval  VERR_INTERNAL_ERROR_4
+ *
+ * @param   pThis               The pipe handle.
+ */
+static int rtPipeTryNonBlocking(RTPIPEINTERNAL *pThis)
+{
+    /*
+     * Update the state.
+     */
+    for (;;)
+    {
+        uint32_t        u32State    = ASMAtomicReadU32(&pThis->u32State);
+        uint32_t const  u32StateOld = u32State;
+        uint32_t const  cUsers      = (u32State & RTPIPE_POSIX_USERS_MASK);
+
+        if (!(u32State & RTPIPE_POSIX_BLOCKING))
+        {
+            AssertReturn(cUsers < RTPIPE_POSIX_USERS_MASK / 2, VERR_INTERNAL_ERROR_4);
+            u32State &= ~RTPIPE_POSIX_USERS_MASK;
+            u32State |= cUsers + 1;
+            if (ASMAtomicCmpXchgU32(&pThis->u32State, u32State, u32StateOld))
+            {
+                if (u32State & RTPIPE_POSIX_SWITCHING)
+                    break;
+                return VINF_SUCCESS;
+            }
+        }
+        else if (cUsers == 0)
+        {
+            u32State = 1 | RTPIPE_POSIX_SWITCHING;
+            if (ASMAtomicCmpXchgU32(&pThis->u32State, u32State, u32StateOld))
+                break;
+        }
+        else
+            return VERR_WRONG_ORDER;
+        ASMNopPause();
+    }
+
+    /*
+     * Do the switching.
+     */
+    int fFlags = fcntl(pThis->fd, F_GETFL, 0);
+    if (fFlags != -1)
+    {
+        if (    (fFlags & O_NONBLOCK)
+            ||  fcntl(pThis->fd, F_SETFL, fFlags | O_NONBLOCK) != -1)
+        {
+            ASMAtomicBitClear(&pThis->u32State, RTPIPE_POSIX_SWITCHING_BIT);
+            return VINF_SUCCESS;
+        }
+    }
+
+    ASMAtomicDecU32(&pThis->u32State);
+    return RTErrConvertFromErrno(errno);
+}
+
+
+/**
+ * Checks if the read pipe has a HUP condition.
+ *
+ * @returns true if HUP, false if no.
+ * @param   pThis               The pipe handle (read).
+ */
+static bool rtPipePosixHasHup(RTPIPEINTERNAL *pThis)
+{
+    Assert(pThis->fRead);
+
+    struct pollfd PollFd;
+    RT_ZERO(PollFd);
+    PollFd.fd      = pThis->fd;
+    PollFd.events  = POLLHUP;
+    return poll(&PollFd, 1, 0) >= 1
+       && (PollFd.revents & POLLHUP);
+}
+
+
+RTDECL(int) RTPipeRead(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbRead);
+    AssertPtr(pvBuf);
+
+    int rc = rtPipeTryNonBlocking(pThis);
+    if (RT_SUCCESS(rc))
+    {
+        ssize_t cbRead = read(pThis->fd, pvBuf, RT_MIN(cbToRead, SSIZE_MAX));
+        if (cbRead >= 0)
+        {
+            if (cbRead || !cbToRead || !rtPipePosixHasHup(pThis))
+                *pcbRead = cbRead;
+            else
+                rc = VERR_BROKEN_PIPE;
+        }
+        else if (errno == EAGAIN)
+        {
+            *pcbRead = 0;
+            rc = VINF_TRY_AGAIN;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+
+        ASMAtomicDecU32(&pThis->u32State);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeReadBlocking(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+
+    int rc = rtPipeTryBlocking(pThis);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbTotalRead = 0;
+        while (cbToRead > 0)
+        {
+            ssize_t cbRead = read(pThis->fd, pvBuf, RT_MIN(cbToRead, SSIZE_MAX));
+            if (cbRead < 0)
+            {
+                rc = RTErrConvertFromErrno(errno);
+                break;
+            }
+            if (!cbRead && rtPipePosixHasHup(pThis))
+            {
+                rc = VERR_BROKEN_PIPE;
+                break;
+            }
+
+            /* advance */
+            pvBuf        = (char *)pvBuf + cbRead;
+            cbTotalRead += cbRead;
+            cbToRead    -= cbRead;
+        }
+
+        if (pcbRead)
+        {
+            *pcbRead = cbTotalRead;
+            if (   RT_FAILURE(rc)
+                && cbTotalRead
+                && rc != VERR_INVALID_POINTER)
+                rc = VINF_SUCCESS;
+        }
+
+        ASMAtomicDecU32(&pThis->u32State);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeWrite(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbWritten);
+    AssertPtr(pvBuf);
+
+    int rc = rtPipeTryNonBlocking(pThis);
+    if (RT_SUCCESS(rc))
+    {
+        if (cbToWrite)
+        {
+            ssize_t cbWritten = write(pThis->fd, pvBuf, RT_MIN(cbToWrite, SSIZE_MAX));
+            if (cbWritten >= 0)
+                *pcbWritten = cbWritten;
+            else if (errno == EAGAIN)
+            {
+                *pcbWritten = 0;
+                rc = VINF_TRY_AGAIN;
+            }
+            else
+                rc = RTErrConvertFromErrno(errno);
+        }
+        else
+            *pcbWritten = 0;
+
+        ASMAtomicDecU32(&pThis->u32State);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeWriteBlocking(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+    AssertPtrNull(pcbWritten);
+
+    int rc = rtPipeTryBlocking(pThis);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbTotalWritten = 0;
+        while (cbToWrite > 0)
+        {
+            ssize_t cbWritten = write(pThis->fd, pvBuf, RT_MIN(cbToWrite, SSIZE_MAX));
+            if (cbWritten < 0)
+            {
+                rc = RTErrConvertFromErrno(errno);
+                break;
+            }
+
+            /* advance */
+            pvBuf           = (char const *)pvBuf + cbWritten;
+            cbTotalWritten += cbWritten;
+            cbToWrite      -= cbWritten;
+        }
+
+        if (pcbWritten)
+        {
+            *pcbWritten = cbTotalWritten;
+            if (   RT_FAILURE(rc)
+                && cbTotalWritten
+                && rc != VERR_INVALID_POINTER)
+                rc = VINF_SUCCESS;
+        }
+
+        ASMAtomicDecU32(&pThis->u32State);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeFlush(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+
+    if (fsync(pThis->fd))
+    {
+        if (errno == EINVAL || errno == ENOTSUP)
+            return VERR_NOT_SUPPORTED;
+        return RTErrConvertFromErrno(errno);
+    }
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTPipeSelectOne(RTPIPE hPipe, RTMSINTERVAL cMillies)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    struct pollfd PollFd;
+    RT_ZERO(PollFd);
+    PollFd.fd      = pThis->fd;
+    PollFd.events  = POLLHUP | POLLERR;
+    if (pThis->fRead)
+        PollFd.events |= POLLIN | POLLPRI;
+    else
+        PollFd.events |= POLLOUT;
+
+    int timeout;
+    if (   cMillies == RT_INDEFINITE_WAIT
+        || cMillies >= INT_MAX /* lazy bird */)
+        timeout = -1;
+    else
+        timeout = cMillies;
+
+    int rc = poll(&PollFd, 1, timeout);
+    if (rc == -1)
+        return RTErrConvertFromErrno(errno);
+    return rc > 0 ? VINF_SUCCESS : VERR_TIMEOUT;
+}
+
+
+RTDECL(int) RTPipeQueryReadable(RTPIPE hPipe, size_t *pcbReadable)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_PIPE_NOT_READ);
+    AssertPtrReturn(pcbReadable, VERR_INVALID_POINTER);
+
+    int cb = 0;
+    int rc = ioctl(pThis->fd, FIONREAD, &cb);
+    if (rc != -1)
+    {
+        AssertStmt(cb >= 0, cb = 0);
+        *pcbReadable = cb;
+        return VINF_SUCCESS;
+    }
+
+    rc = errno;
+    if (rc == ENOTTY)
+        rc = VERR_NOT_SUPPORTED;
+    else
+        rc = RTErrConvertFromErrno(rc);
+    return rc;
+}
+
+
+RTDECL(int) RTPipeQueryInfo(RTPIPE hPipe, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, 0);
+
+    rtPipeFakeQueryInfo(pObjInfo, enmAddAttr, pThis->fRead);
+
+    if (pThis->fRead)
+    {
+        int cb = 0;
+        int rc = ioctl(pThis->fd, FIONREAD, &cb);
+        if (rc >= 0)
+            pObjInfo->cbObject = cb;
+    }
+#ifdef FIONSPACE
+    else
+    {
+        int cb = 0;
+        int rc = ioctl(pThis->fd, FIONSPACE, &cb);
+        if (rc >= 0)
+            pObjInfo->cbObject = cb;
+    }
+#endif
+
+    /** @todo Check this out on linux, solaris and darwin... (Currently going by a
+     *        FreeBSD manpage.) */
+    struct stat St;
+    if (fstat(pThis->fd, &St))
+    {
+        pObjInfo->cbAllocated = St.st_blksize;
+        if (   enmAddAttr == RTFSOBJATTRADD_NOTHING
+            || enmAddAttr == RTFSOBJATTRADD_UNIX)
+        {
+            pObjInfo->Attr.enmAdditional = RTFSOBJATTRADD_UNIX;
+            pObjInfo->Attr.u.Unix.INodeId       = St.st_ino;
+            pObjInfo->Attr.u.Unix.INodeIdDevice = St.st_dev;
+        }
+    }
+    /** @todo error handling?  */
+
+    return VINF_SUCCESS;
+}
+
+
+int rtPipePollGetHandle(RTPIPE hPipe, uint32_t fEvents, PRTHCINTPTR phNative)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    AssertReturn(!(fEvents & RTPOLL_EVT_READ)  || pThis->fRead,  VERR_INVALID_PARAMETER);
+    AssertReturn(!(fEvents & RTPOLL_EVT_WRITE) || !pThis->fRead, VERR_INVALID_PARAMETER);
+
+    *phNative = pThis->fd;
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/process-creation-posix.cpp b/src/VBox/Runtime/r3/posix/process-creation-posix.cpp
new file mode 100644
index 00000000..6cf7be73
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/process-creation-posix.cpp
@@ -0,0 +1,2408 @@
+/* $Id: process-creation-posix.cpp $ */
+/** @file
+ * IPRT - Process Creation, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/cdefs.h>
+#ifdef RT_OS_LINUX
+# define IPRT_WITH_DYNAMIC_CRYPT_R
+#endif
+#if (defined(RT_OS_LINUX) || defined(RT_OS_OS2)) && !defined(_GNU_SOURCE)
+# define _GNU_SOURCE
+#endif
+#if defined(RT_OS_LINUX) && !defined(_XOPEN_SOURCE)
+# define _XOPEN_SOURCE 700 /* for newlocale */
+#endif
+
+#ifdef RT_OS_OS2
+# define crypt   unistd_crypt
+# define setkey  unistd_setkey
+# define encrypt unistd_encrypt
+# include <unistd.h>
+# undef  crypt
+# undef  setkey
+# undef  encrypt
+#else
+# include <unistd.h>
+#endif
+#include <stdlib.h>
+#include <errno.h>
+#include <langinfo.h>
+#include <locale.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <grp.h>
+#include <pwd.h>
+#if defined(RT_OS_LINUX) || defined(RT_OS_OS2) || defined(RT_OS_SOLARIS)
+# include <crypt.h>
+#endif
+#if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS)
+# include <shadow.h>
+#endif
+#if defined(RT_OS_DARWIN)
+# include <xlocale.h> /* for newlocale() */
+#endif
+
+#if defined(RT_OS_LINUX) || defined(RT_OS_OS2)
+/* While Solaris has posix_spawn() of course we don't want to use it as
+ * we need to have the child in a different process contract, no matter
+ * whether it is started detached or not. */
+# define HAVE_POSIX_SPAWN 1
+#endif
+#if defined(RT_OS_DARWIN) && defined(MAC_OS_X_VERSION_MIN_REQUIRED)
+# if MAC_OS_X_VERSION_MIN_REQUIRED >= 1050
+#  define HAVE_POSIX_SPAWN 1
+# endif
+#endif
+#ifdef HAVE_POSIX_SPAWN
+# include <spawn.h>
+#endif
+
+#if !defined(IPRT_USE_PAM) \
+ && !defined(IPRT_WITHOUT_PAM) \
+ && ( defined(RT_OS_DARWIN) || defined(RT_OS_FREEBSD) || defined(RT_OS_LINUX) || defined(RT_OS_NETBSD) || defined(RT_OS_OPENBSD) || defined(RT_OS_SOLARIS) )
+# define IPRT_USE_PAM
+#endif
+#ifdef IPRT_USE_PAM
+# include <security/pam_appl.h>
+# include <stdlib.h>
+# include <dlfcn.h>
+# include <iprt/asm.h>
+#endif
+
+#ifdef RT_OS_SOLARIS
+# include <limits.h>
+# include <sys/ctfs.h>
+# include <sys/contract/process.h>
+# include <libcontract.h>
+#endif
+
+#ifndef RT_OS_SOLARIS
+# include <paths.h>
+#else
+# define _PATH_MAILDIR "/var/mail"
+# define _PATH_DEFPATH "/usr/bin:/bin"
+# define _PATH_STDPATH "/sbin:/usr/sbin:/bin:/usr/bin"
+#endif
+#ifndef _PATH_BSHELL
+# define _PATH_BSHELL "/bin/sh"
+#endif
+
+
+#include <iprt/process.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#if defined(IPRT_WITH_DYNAMIC_CRYPT_R) || defined(IPRT_USE_PAM)
+# include <iprt/ldr.h>
+#endif
+#include <iprt/log.h>
+#include <iprt/path.h>
+#include <iprt/pipe.h>
+#include <iprt/socket.h>
+#include <iprt/string.h>
+#include <iprt/mem.h>
+#include "internal/process.h"
+#include "internal/path.h"
+#include "internal/string.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef IPRT_USE_PAM
+/*
+ * The PAM library names and version ranges to try.
+ */
+# ifdef RT_OS_DARWIN
+#  include <mach-o/dyld.h>
+/** @node libpam.2.dylib was introduced with 10.6.x (OpenPAM); we use
+ *        libpam.dylib as that's a symlink to the latest and greatest. */
+#  define IPRT_LIBPAM_FILE_1            "libpam.dylib"
+#  define IPRT_LIBPAM_FILE_1_FIRST_VER 0
+#  define IPRT_LIBPAM_FILE_1_END_VER   0
+#  define IPRT_LIBPAM_FILE_2            "libpam.2.dylib"
+#  define IPRT_LIBPAM_FILE_2_FIRST_VER 0
+#  define IPRT_LIBPAM_FILE_2_END_VER   0
+#  define IPRT_LIBPAM_FILE_3            "libpam.1.dylib"
+#  define IPRT_LIBPAM_FILE_3_FIRST_VER 0
+#  define IPRT_LIBPAM_FILE_3_END_VER   0
+# elif RT_OS_LINUX
+#  define IPRT_LIBPAM_FILE_1           "libpam.so.0"
+#  define IPRT_LIBPAM_FILE_1_FIRST_VER 0
+#  define IPRT_LIBPAM_FILE_1_END_VER   0
+#  define IPRT_LIBPAM_FILE_2           "libpam.so"
+#  define IPRT_LIBPAM_FILE_2_FIRST_VER 16
+#  define IPRT_LIBPAM_FILE_2_END_VER   1
+# else
+#  define IPRT_LIBPAM_FILE_1           "libpam.so"
+#  define IPRT_LIBPAM_FILE_1_FIRST_VER 16
+#  define IPRT_LIBPAM_FILE_1_END_VER   0
+# endif
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+#ifdef IPRT_USE_PAM
+/** For passing info between rtCheckCredentials and rtPamConv. */
+typedef struct RTPROCPAMARGS
+{
+    const char *pszUser;
+    const char *pszPassword;
+} RTPROCPAMARGS;
+/** Pointer to rtPamConv argument package. */
+typedef RTPROCPAMARGS *PRTPROCPAMARGS;
+#endif
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Environment dump marker used with CSH.   */
+static const char g_szEnvMarkerBegin[] = "IPRT_EnvEnvEnv_Begin_EnvEnvEnv";
+/** Environment dump marker used with CSH.   */
+static const char g_szEnvMarkerEnd[]   = "IPRT_EnvEnvEnv_End_EnvEnvEnv";
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static int rtProcPosixCreateInner(const char *pszExec, const char * const *papszArgs, RTENV hEnv, RTENV hEnvToUse,
+                                  uint32_t fFlags, const char *pszAsUser, uid_t uid, gid_t gid,
+                                  unsigned cRedirFds, int *paRedirFds, PRTPROCESS phProcess);
+
+
+#ifdef IPRT_USE_PAM
+/**
+ * Worker for rtCheckCredentials that feeds password and maybe username to PAM.
+ *
+ * @returns PAM status.
+ * @param   cMessages       Number of messages.
+ * @param   papMessages     Message vector.
+ * @param   ppaResponses    Where to put our responses.
+ * @param   pvAppData       Pointer to RTPROCPAMARGS.
+ */
+#if defined(RT_OS_SOLARIS)
+static int rtPamConv(int cMessages, struct pam_message **papMessages, struct pam_response **ppaResponses, void *pvAppData)
+#else
+static int rtPamConv(int cMessages, const struct pam_message **papMessages, struct pam_response **ppaResponses, void *pvAppData)
+#endif
+{
+    LogFlow(("rtPamConv: cMessages=%d\n", cMessages));
+    PRTPROCPAMARGS pArgs = (PRTPROCPAMARGS)pvAppData;
+    AssertPtrReturn(pArgs, PAM_CONV_ERR);
+
+    struct pam_response *paResponses = (struct pam_response *)calloc(cMessages, sizeof(paResponses[0]));
+    AssertReturn(paResponses,  PAM_CONV_ERR);
+    for (int i = 0; i < cMessages; i++)
+    {
+        LogFlow(("rtPamConv: #%d: msg_style=%d msg=%s\n", i, papMessages[i]->msg_style, papMessages[i]->msg));
+
+        paResponses[i].resp_retcode = 0;
+        if (papMessages[i]->msg_style == PAM_PROMPT_ECHO_OFF)
+            paResponses[i].resp = strdup(pArgs->pszPassword);
+        else if (papMessages[i]->msg_style == PAM_PROMPT_ECHO_ON)
+            paResponses[i].resp = strdup(pArgs->pszUser);
+        else
+        {
+            paResponses[i].resp = NULL;
+            continue;
+        }
+        if (paResponses[i].resp == NULL)
+        {
+            while (i-- > 0)
+                free(paResponses[i].resp);
+            free(paResponses);
+            LogFlow(("rtPamConv: out of memory\n"));
+            return PAM_CONV_ERR;
+        }
+    }
+
+    *ppaResponses = paResponses;
+    return PAM_SUCCESS;
+}
+
+
+/**
+ * Common PAM driver for rtCheckCredentials and the case where pszAsUser is NULL
+ * but RTPROC_FLAGS_PROFILE is set.
+ *
+ * @returns IPRT status code.
+ * @param   pszPamService   The PAM service to use for the run.
+ * @param   pszUser         The user.
+ * @param   pszPassword     The password.
+ * @param   ppapszEnv       Where to return PAM environment variables, NULL is
+ *                          fine if no variables to return. Call
+ *                          rtProcPosixFreePamEnv to free.  Optional, so NULL
+ *                          can be passed in.
+ * @param   pfMayFallBack   Where to return whether a fallback to crypt is
+ *                          acceptable or if the failure result is due to
+ *                          authentication failing.  Optional.
+ */
+static int rtProcPosixAuthenticateUsingPam(const char *pszPamService, const char *pszUser, const char *pszPassword,
+                                           char ***ppapszEnv, bool *pfMayFallBack)
+{
+    if (pfMayFallBack)
+        *pfMayFallBack = true;
+
+    /*
+     * Dynamically load pam the first time we go thru here.
+     */
+    static int     (*s_pfnPamStart)(const char *, const char *, struct pam_conv *, pam_handle_t **);
+    static int     (*s_pfnPamAuthenticate)(pam_handle_t *, int);
+    static int     (*s_pfnPamAcctMgmt)(pam_handle_t *, int);
+    static int     (*s_pfnPamSetItem)(pam_handle_t *, int, const void *);
+    static int     (*s_pfnPamSetCred)(pam_handle_t *, int);
+    static char ** (*s_pfnPamGetEnvList)(pam_handle_t *);
+    static int     (*s_pfnPamOpenSession)(pam_handle_t *, int);
+    static int     (*s_pfnPamCloseSession)(pam_handle_t *, int);
+    static int     (*s_pfnPamEnd)(pam_handle_t *, int);
+    if (   s_pfnPamStart == NULL
+        || s_pfnPamAuthenticate == NULL
+        || s_pfnPamAcctMgmt == NULL
+        || s_pfnPamSetItem == NULL
+        || s_pfnPamEnd == NULL)
+    {
+        RTLDRMOD hModPam = NIL_RTLDRMOD;
+        const char *pszLast;
+        int rc = RTLdrLoadSystemEx(pszLast = IPRT_LIBPAM_FILE_1, RTLDRLOAD_FLAGS_GLOBAL | RTLDRLOAD_FLAGS_NO_UNLOAD
+                                   | RTLDRLOAD_FLAGS_SO_VER_RANGE(IPRT_LIBPAM_FILE_1_FIRST_VER, IPRT_LIBPAM_FILE_1_END_VER),
+                                   &hModPam);
+# ifdef IPRT_LIBPAM_FILE_2
+        if (RT_FAILURE(rc))
+            rc = RTLdrLoadSystemEx(pszLast = IPRT_LIBPAM_FILE_2, RTLDRLOAD_FLAGS_GLOBAL | RTLDRLOAD_FLAGS_NO_UNLOAD
+                                   | RTLDRLOAD_FLAGS_SO_VER_RANGE(IPRT_LIBPAM_FILE_2_FIRST_VER, IPRT_LIBPAM_FILE_2_END_VER),
+                                   &hModPam);
+# endif
+# ifdef IPRT_LIBPAM_FILE_3
+        if (RT_FAILURE(rc))
+            rc = RTLdrLoadSystemEx(pszLast = IPRT_LIBPAM_FILE_3, RTLDRLOAD_FLAGS_GLOBAL | RTLDRLOAD_FLAGS_NO_UNLOAD
+                                   | RTLDRLOAD_FLAGS_SO_VER_RANGE(IPRT_LIBPAM_FILE_3_FIRST_VER, IPRT_LIBPAM_FILE_3_END_VER),
+                                   &hModPam);
+# endif
+        if (RT_FAILURE(rc))
+        {
+            LogRelMax(10, ("failed to load %s: %Rrc\n", pszLast, rc));
+            return VERR_AUTHENTICATION_FAILURE;
+        }
+
+        *(uintptr_t *)&s_pfnPamStart        = (uintptr_t)RTLdrGetFunction(hModPam, "pam_start");
+        *(uintptr_t *)&s_pfnPamAuthenticate = (uintptr_t)RTLdrGetFunction(hModPam, "pam_authenticate");
+        *(uintptr_t *)&s_pfnPamAcctMgmt     = (uintptr_t)RTLdrGetFunction(hModPam, "pam_acct_mgmt");
+        *(uintptr_t *)&s_pfnPamSetItem      = (uintptr_t)RTLdrGetFunction(hModPam, "pam_set_item");
+        *(uintptr_t *)&s_pfnPamSetCred      = (uintptr_t)RTLdrGetFunction(hModPam, "pam_setcred");
+        *(uintptr_t *)&s_pfnPamGetEnvList   = (uintptr_t)RTLdrGetFunction(hModPam, "pam_getenvlist");
+        *(uintptr_t *)&s_pfnPamOpenSession  = (uintptr_t)RTLdrGetFunction(hModPam, "pam_open_session");
+        *(uintptr_t *)&s_pfnPamCloseSession = (uintptr_t)RTLdrGetFunction(hModPam, "pam_close_session");
+        *(uintptr_t *)&s_pfnPamEnd          = (uintptr_t)RTLdrGetFunction(hModPam, "pam_end");
+        ASMCompilerBarrier();
+
+        RTLdrClose(hModPam);
+
+        if (   s_pfnPamStart == NULL
+            || s_pfnPamAuthenticate == NULL
+            || s_pfnPamAcctMgmt == NULL
+            || s_pfnPamSetItem == NULL
+            || s_pfnPamEnd == NULL)
+        {
+            LogRelMax(10, ("failed to resolve symbols: %p %p %p %p %p\n",
+                           s_pfnPamStart, s_pfnPamAuthenticate, s_pfnPamAcctMgmt, s_pfnPamSetItem, s_pfnPamEnd));
+            return VERR_AUTHENTICATION_FAILURE;
+        }
+    }
+
+# define pam_start           s_pfnPamStart
+# define pam_authenticate    s_pfnPamAuthenticate
+# define pam_acct_mgmt       s_pfnPamAcctMgmt
+# define pam_set_item        s_pfnPamSetItem
+# define pam_setcred         s_pfnPamSetCred
+# define pam_getenvlist      s_pfnPamGetEnvList
+# define pam_open_session    s_pfnPamOpenSession
+# define pam_close_session   s_pfnPamCloseSession
+# define pam_end             s_pfnPamEnd
+
+    /*
+     * Do the PAM stuff.
+     */
+    pam_handle_t   *hPam        = NULL;
+    RTPROCPAMARGS   PamConvArgs = { pszUser, pszPassword };
+    struct pam_conv PamConversation;
+    RT_ZERO(PamConversation);
+    PamConversation.appdata_ptr = &PamConvArgs;
+    PamConversation.conv        = rtPamConv;
+    int rc = pam_start(pszPamService, pszUser, &PamConversation, &hPam);
+    if (rc == PAM_SUCCESS)
+    {
+        rc = pam_set_item(hPam, PAM_RUSER, pszUser);
+        LogRel2(("rtProcPosixAuthenticateUsingPam(%s): pam_setitem/PAM_RUSER: %s\n", pszPamService, pszUser));
+        if (rc == PAM_SUCCESS)
+        {
+            /*
+             * Secure TTY fun ahead (for pam_securetty).
+             *
+             * We need to set PAM_TTY (if available) to make PAM stacks work which
+             * require a secure TTY via pam_securetty (Debian 10 + 11, for example). This
+             * is typically an issue when launching as 'root'.  See @bugref{10225}.
+             *
+             * Note! We only can try (or better: guess) to a certain amount, as it really
+             *       depends on the distribution or Administrator which has set up the
+             *       system which (and how) things are allowed (see /etc/securetty).
+             *
+             * Note! We don't acctually try or guess anything about the distro like
+             *       suggested by the above note, we just try determine the TTY of
+             *       the _parent_ process and hope for the best. (bird)
+             */
+            char szTTY[64];
+            int rc2 = RTEnvGetEx(RTENV_DEFAULT, "DISPLAY", szTTY, sizeof(szTTY), NULL);
+            if (RT_FAILURE(rc2))
+            {
+                /* Virtual terminal hint given? */
+                static char const s_szPrefix[] = "tty";
+                memcpy(szTTY, s_szPrefix, sizeof(s_szPrefix));
+                rc2 = RTEnvGetEx(RTENV_DEFAULT, "XDG_VTNR", &szTTY[sizeof(s_szPrefix) - 1], sizeof(s_szPrefix) - 1, NULL);
+            }
+
+            /** @todo Should we - distinguished from the login service - also set the hostname as PAM_TTY?
+             *        The pam_access and pam_systemd talk about this. Similarly, SSH and cron use "ssh" and "cron" for PAM_TTY
+             *        (see PAM_TTY_KLUDGE). */
+#ifdef IPRT_WITH_PAM_TTY_KLUDGE
+            if (RT_FAILURE(rc2))
+                if (!RTStrICmp(pszPamService, "access")) /* Access management needed? */
+                {
+                    int err = gethostname(szTTY, sizeof(szTTY));
+                    if (err == 0)
+                        rc2 = VINF_SUCCESS;
+                }
+#endif
+            /* As a last resort, try stdin's TTY name instead (if any). */
+            if (RT_FAILURE(rc2))
+            {
+                rc2 = ttyname_r(0 /*stdin*/, szTTY, sizeof(szTTY));
+                if (rc2 != 0)
+                    rc2 = RTErrConvertFromErrno(rc2);
+            }
+
+            LogRel2(("rtProcPosixAuthenticateUsingPam(%s): pam_setitem/PAM_TTY: %s, rc2=%Rrc\n", pszPamService, szTTY, rc2));
+            if (szTTY[0] == '\0')
+                LogRel2(("rtProcPosixAuthenticateUsingPam(%s): Hint: Looks like running as a non-interactive user (no TTY/PTY).\n"
+                         "Authentication requiring a secure terminal might fail.\n", pszPamService));
+
+            if (   RT_SUCCESS(rc2)
+                && szTTY[0] != '\0') /* Only try using PAM_TTY if we have something to set. */
+                rc = pam_set_item(hPam, PAM_TTY, szTTY);
+
+            if (rc == PAM_SUCCESS)
+            {
+                /* From this point on we don't allow falling back to other auth methods. */
+                if (pfMayFallBack)
+                    *pfMayFallBack = false;
+
+                rc = pam_authenticate(hPam, 0);
+                if (rc == PAM_SUCCESS)
+                {
+                    rc = pam_acct_mgmt(hPam, 0);
+                    if (   rc == PAM_SUCCESS
+                        || rc == PAM_AUTHINFO_UNAVAIL /*??*/)
+                    {
+                        if (   ppapszEnv
+                            && s_pfnPamGetEnvList
+                            && s_pfnPamSetCred)
+                        {
+                            /* pam_env.so creates the environment when pam_setcred is called,. */
+                            int rcSetCred = pam_setcred(hPam, PAM_ESTABLISH_CRED | PAM_SILENT);
+                            /** @todo check pam_setcred status code? */
+
+                            /* Unless it does it during session opening (Ubuntu 21.10).  This
+                               unfortunately means we might mount user dir and other crap: */
+                            /** @todo do session handling properly   */
+                            int rcOpenSession = PAM_ABORT;
+                            if (   s_pfnPamOpenSession
+                                && s_pfnPamCloseSession)
+                                rcOpenSession = pam_open_session(hPam, PAM_SILENT);
+
+                            *ppapszEnv = pam_getenvlist(hPam);
+                            LogFlowFunc(("pam_getenvlist -> %p ([0]=%p); rcSetCred=%d rcOpenSession=%d\n",
+                                         *ppapszEnv, *ppapszEnv ? **ppapszEnv : NULL, rcSetCred, rcOpenSession)); RT_NOREF(rcSetCred);
+
+                            if (rcOpenSession == PAM_SUCCESS)
+                                pam_close_session(hPam, PAM_SILENT);
+                            pam_setcred(hPam, PAM_DELETE_CRED);
+                        }
+
+                        pam_end(hPam, PAM_SUCCESS);
+                        LogFlowFunc(("pam auth (for %s) successful\n", pszPamService));
+                        return VINF_SUCCESS;
+                    }
+                    LogFunc(("pam_acct_mgmt -> %d\n", rc));
+                }
+                else
+                    LogFunc(("pam_authenticate -> %d\n", rc));
+            }
+            else
+                LogFunc(("pam_setitem/PAM_TTY -> %d\n", rc));
+        }
+        else
+            LogFunc(("pam_set_item/PAM_RUSER -> %d\n", rc));
+        pam_end(hPam, rc);
+    }
+    else
+        LogFunc(("pam_start(%s) -> %d\n", pszPamService, rc));
+
+    LogRel2(("rtProcPosixAuthenticateUsingPam(%s): Failed authenticating user '%s' with %d\n", pszPamService, pszUser, rc));
+    return VERR_AUTHENTICATION_FAILURE;
+}
+
+
+/**
+ * Checks if the given service file is present in any of the pam.d directories.
+ */
+static bool rtProcPosixPamServiceExists(const char *pszService)
+{
+    char szPath[256];
+
+    /* PAM_CONFIG_D: */
+    int rc = RTPathJoin(szPath, sizeof(szPath), "/etc/pam.d/", pszService); AssertRC(rc);
+    if (RTFileExists(szPath))
+        return true;
+
+    /* PAM_CONFIG_DIST_D: */
+    rc = RTPathJoin(szPath, sizeof(szPath), "/usr/lib/pam.d/", pszService); AssertRC(rc);
+    if (RTFileExists(szPath))
+        return true;
+
+    /* No support for PAM_CONFIG_DIST2_D. */
+    return false;
+}
+
+#endif /* IPRT_USE_PAM */
+
+
+#if defined(IPRT_WITH_DYNAMIC_CRYPT_R)
+/** Pointer to crypt_r(). */
+typedef char *(*PFNCRYPTR)(const char *, const char *, struct crypt_data *);
+
+/**
+ * Wrapper for resolving and calling crypt_r dynamically.
+ *
+ * The reason for this is that fedora 30+ wants to use libxcrypt rather than the
+ * glibc libcrypt.  The two libraries has different crypt_data sizes and layout,
+ * so we allocate a 256KB data block to be on the safe size (caller does this).
+ */
+static char *rtProcDynamicCryptR(const char *pszKey, const char *pszSalt, struct crypt_data *pData)
+{
+    static PFNCRYPTR volatile s_pfnCryptR = NULL;
+    PFNCRYPTR pfnCryptR = s_pfnCryptR;
+    if (pfnCryptR)
+        return pfnCryptR(pszKey, pszSalt, pData);
+
+    pfnCryptR = (PFNCRYPTR)(uintptr_t)RTLdrGetSystemSymbolEx("libcrypt.so", "crypt_r", RTLDRLOAD_FLAGS_SO_VER_RANGE(1, 6));
+    if (!pfnCryptR)
+        pfnCryptR = (PFNCRYPTR)(uintptr_t)RTLdrGetSystemSymbolEx("libxcrypt.so", "crypt_r", RTLDRLOAD_FLAGS_SO_VER_RANGE(1, 32));
+    if (pfnCryptR)
+    {
+        s_pfnCryptR = pfnCryptR;
+        return pfnCryptR(pszKey, pszSalt, pData);
+    }
+
+    LogRel(("IPRT/RTProc: Unable to locate crypt_r!\n"));
+    return NULL;
+}
+#endif /* IPRT_WITH_DYNAMIC_CRYPT_R */
+
+
+/** Free the environment list returned by rtCheckCredentials. */
+static void rtProcPosixFreePamEnv(char **papszEnv)
+{
+    if (papszEnv)
+    {
+        for (size_t i = 0; papszEnv[i] != NULL; i++)
+            free(papszEnv[i]);
+        free(papszEnv);
+    }
+}
+
+
+/**
+ * Check the credentials and return the gid/uid of user.
+ *
+ * @param    pszUser    The username.
+ * @param    pszPasswd  The password to authenticate with.
+ * @param    gid        Where to store the GID of the user.
+ * @param    uid        Where to store the UID of the user.
+ * @param    ppapszEnv  Where to return PAM environment variables, NULL is fine
+ *                      if no variables to return. Call rtProcPosixFreePamEnv to
+ *                      free. Optional, so NULL can be passed in.
+ * @returns IPRT status code
+ */
+static int rtCheckCredentials(const char *pszUser, const char *pszPasswd, gid_t *pGid, uid_t *pUid, char ***ppapszEnv)
+{
+    Log(("rtCheckCredentials: pszUser=%s\n", pszUser));
+    int rc;
+
+    if (ppapszEnv)
+        *ppapszEnv = NULL;
+
+    /*
+     * Resolve user to UID and GID.
+     */
+    char            achBuf[_4K];
+    struct passwd   Pw;
+    struct passwd  *pPw;
+    if (getpwnam_r(pszUser, &Pw, achBuf, sizeof(achBuf), &pPw) != 0)
+        return VERR_AUTHENTICATION_FAILURE;
+    if (!pPw)
+        return VERR_AUTHENTICATION_FAILURE;
+
+    *pUid = pPw->pw_uid;
+    *pGid = pPw->pw_gid;
+
+#ifdef IPRT_USE_PAM
+    /*
+     * Try authenticate using PAM, and falling back on crypto if allowed.
+     */
+    const char *pszService = "iprt-as-user";
+    if (!rtProcPosixPamServiceExists("iprt-as-user"))
+# ifdef IPRT_PAM_NATIVE_SERVICE_NAME_AS_USER
+        pszService = IPRT_PAM_NATIVE_SERVICE_NAME_AS_USER;
+# else
+        pszService = "login";
+# endif
+    bool fMayFallBack = false;
+    rc = rtProcPosixAuthenticateUsingPam(pszService, pszUser, pszPasswd, ppapszEnv, &fMayFallBack);
+    if (RT_SUCCESS(rc) || !fMayFallBack)
+    {
+        RTMemWipeThoroughly(achBuf, sizeof(achBuf), 3);
+        return rc;
+    }
+#endif
+
+#if !defined(IPRT_USE_PAM) || defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS) || defined(RT_OS_OS2)
+# if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS)
+    /*
+     * Ditto for /etc/shadow and replace pw_passwd from above if we can access it:
+     *
+     * Note! On FreeBSD and OS/2 the root user will open /etc/shadow above, so
+     *       this getspnam_r step is not necessary.
+     */
+    struct spwd  ShwPwd;
+    char         achBuf2[_4K];
+#  if defined(RT_OS_LINUX)
+    struct spwd *pShwPwd = NULL;
+    if (getspnam_r(pszUser, &ShwPwd, achBuf2, sizeof(achBuf2), &pShwPwd) != 0)
+        pShwPwd = NULL;
+#  else
+    struct spwd *pShwPwd = getspnam_r(pszUser, &ShwPwd, achBuf2, sizeof(achBuf2));
+#  endif
+    if (pShwPwd != NULL)
+        pPw->pw_passwd = pShwPwd->sp_pwdp;
+# endif
+
+    /*
+     * Encrypt the passed in password and see if it matches.
+     */
+# if defined(RT_OS_LINUX)
+    /* Default fCorrect=true if no password specified. In that case, pPw->pw_passwd
+       must be NULL (no password set for this user). Fail if a password is specified
+       but the user does not have one assigned. */
+    rc = !pszPasswd || !*pszPasswd ? VINF_SUCCESS : VERR_AUTHENTICATION_FAILURE;
+    if (pPw->pw_passwd && *pPw->pw_passwd)
+# endif
+    {
+# if defined(RT_OS_LINUX) || defined(RT_OS_OS2)
+#  ifdef IPRT_WITH_DYNAMIC_CRYPT_R
+        size_t const       cbCryptData = RT_MAX(sizeof(struct crypt_data) * 2, _256K);
+#  else
+        size_t const       cbCryptData = sizeof(struct crypt_data);
+#  endif
+        struct crypt_data *pCryptData  = (struct crypt_data *)RTMemTmpAllocZ(cbCryptData);
+        if (pCryptData)
+        {
+#  ifdef IPRT_WITH_DYNAMIC_CRYPT_R
+            char *pszEncPasswd = rtProcDynamicCryptR(pszPasswd, pPw->pw_passwd, pCryptData);
+#  else
+            char *pszEncPasswd = crypt_r(pszPasswd, pPw->pw_passwd, pCryptData);
+#  endif
+            rc = pszEncPasswd && !strcmp(pszEncPasswd, pPw->pw_passwd) ? VINF_SUCCESS : VERR_AUTHENTICATION_FAILURE;
+            RTMemWipeThoroughly(pCryptData, cbCryptData, 3);
+            RTMemTmpFree(pCryptData);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+# else
+        char *pszEncPasswd = crypt(pszPasswd, pPw->pw_passwd);
+        rc = strcmp(pszEncPasswd, pPw->pw_passwd) == 0 ? VINF_SUCCESS : VERR_AUTHENTICATION_FAILURE;
+# endif
+    }
+
+    /*
+     * Return GID and UID on success.  Always wipe stack buffers.
+     */
+    if (RT_SUCCESS(rc))
+    {
+        *pGid = pPw->pw_gid;
+        *pUid = pPw->pw_uid;
+    }
+# if defined(RT_OS_LINUX) || defined(RT_OS_SOLARIS)
+    RTMemWipeThoroughly(achBuf2, sizeof(achBuf2), 3);
+# endif
+#endif
+    RTMemWipeThoroughly(achBuf, sizeof(achBuf), 3);
+    return rc;
+}
+
+#ifdef RT_OS_SOLARIS
+
+/** @todo the error reporting of the Solaris process contract code could be
+ * a lot better, but essentially it is not meant to run into errors after
+ * the debugging phase. */
+static int rtSolarisContractPreFork(void)
+{
+    int templateFd = open64(CTFS_ROOT "/process/template", O_RDWR);
+    if (templateFd < 0)
+        return -1;
+
+    /* Set template parameters and event sets. */
+    if (ct_pr_tmpl_set_param(templateFd, CT_PR_PGRPONLY))
+    {
+        close(templateFd);
+        return -1;
+    }
+    if (ct_pr_tmpl_set_fatal(templateFd, CT_PR_EV_HWERR))
+    {
+        close(templateFd);
+        return -1;
+    }
+    if (ct_tmpl_set_critical(templateFd, 0))
+    {
+        close(templateFd);
+        return -1;
+    }
+    if (ct_tmpl_set_informative(templateFd, CT_PR_EV_HWERR))
+    {
+        close(templateFd);
+        return -1;
+    }
+
+    /* Make this the active template for the process. */
+    if (ct_tmpl_activate(templateFd))
+    {
+        close(templateFd);
+        return -1;
+    }
+
+    return templateFd;
+}
+
+static void rtSolarisContractPostForkChild(int templateFd)
+{
+    if (templateFd == -1)
+        return;
+
+    /* Clear the active template. */
+    ct_tmpl_clear(templateFd);
+    close(templateFd);
+}
+
+static void rtSolarisContractPostForkParent(int templateFd, pid_t pid)
+{
+    if (templateFd == -1)
+        return;
+
+    /* Clear the active template. */
+    int cleared = ct_tmpl_clear(templateFd);
+    close(templateFd);
+
+    /* If the clearing failed or the fork failed there's nothing more to do. */
+    if (cleared || pid <= 0)
+        return;
+
+    /* Look up the contract which was created by this thread. */
+    int statFd = open64(CTFS_ROOT "/process/latest", O_RDONLY);
+    if (statFd == -1)
+        return;
+    ct_stathdl_t statHdl;
+    if (ct_status_read(statFd, CTD_COMMON, &statHdl))
+    {
+        close(statFd);
+        return;
+    }
+    ctid_t ctId = ct_status_get_id(statHdl);
+    ct_status_free(statHdl);
+    close(statFd);
+    if (ctId < 0)
+        return;
+
+    /* Abandon this contract we just created. */
+    char ctlPath[PATH_MAX];
+    size_t len = snprintf(ctlPath, sizeof(ctlPath),
+                          CTFS_ROOT "/process/%ld/ctl", (long)ctId);
+    if (len >= sizeof(ctlPath))
+        return;
+    int ctlFd = open64(ctlPath, O_WRONLY);
+    if (statFd == -1)
+        return;
+    if (ct_ctl_abandon(ctlFd) < 0)
+    {
+        close(ctlFd);
+        return;
+    }
+    close(ctlFd);
+}
+
+#endif /* RT_OS_SOLARIS */
+
+
+RTR3DECL(int)   RTProcCreate(const char *pszExec, const char * const *papszArgs, RTENV Env, unsigned fFlags, PRTPROCESS pProcess)
+{
+    return RTProcCreateEx(pszExec, papszArgs, Env, fFlags,
+                          NULL, NULL, NULL,  /* standard handles */
+                          NULL /*pszAsUser*/, NULL /* pszPassword*/, NULL /*pvExtraData*/,
+                          pProcess);
+}
+
+
+/**
+ * Adjust the profile environment after forking the child process and changing
+ * the UID.
+ *
+ * @returns IRPT status code.
+ * @param   hEnvToUse       The environment we're going to use with execve.
+ * @param   fFlags          The process creation flags.
+ * @param   hEnv            The environment passed in by the user.
+ */
+static int rtProcPosixAdjustProfileEnvFromChild(RTENV hEnvToUse, uint32_t fFlags, RTENV hEnv)
+{
+    int rc = VINF_SUCCESS;
+#ifdef RT_OS_DARWIN
+    if (   RT_SUCCESS(rc)
+        && (!(fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD) || RTEnvExistEx(hEnv, "TMPDIR")) )
+    {
+        char szValue[RTPATH_MAX];
+        size_t cbNeeded = confstr(_CS_DARWIN_USER_TEMP_DIR, szValue, sizeof(szValue));
+        if (cbNeeded > 0 && cbNeeded < sizeof(szValue))
+        {
+            char *pszTmp;
+            rc = RTStrCurrentCPToUtf8(&pszTmp, szValue);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTEnvSetEx(hEnvToUse, "TMPDIR", pszTmp);
+                RTStrFree(pszTmp);
+            }
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+#else
+    RT_NOREF_PV(hEnvToUse); RT_NOREF_PV(fFlags); RT_NOREF_PV(hEnv);
+#endif
+    return rc;
+}
+
+
+/**
+ * Undos quoting and escape sequences and looks for stop characters.
+ *
+ * @returns Where to continue scanning in @a pszString.  This points to the
+ *          next character after the stop character, but for the zero terminator
+ *          it points to the terminator character.
+ * @param   pszString           The string to undo quoting and escaping for.
+ *                              This is both input and output as the work is
+ *                              done in place.
+ * @param   pfStoppedOnEqual    Where to return whether we stopped work on a
+ *                              plain equal characater or not.  If this is NULL,
+ *                              then the equal character is not a stop
+ *                              character, then only newline and the zero
+ *                              terminator are.
+ */
+static char *rtProcPosixProfileEnvUnquoteAndUnescapeString(char *pszString, bool *pfStoppedOnEqual)
+{
+    if (pfStoppedOnEqual)
+        *pfStoppedOnEqual = false;
+
+    enum { kPlain, kSingleQ, kDoubleQ } enmState = kPlain;
+    char *pszDst = pszString;
+    for (;;)
+    {
+        char ch = *pszString++;
+        switch (ch)
+        {
+            default:
+                *pszDst++ = ch;
+                break;
+
+            case '\\':
+            {
+                char ch2;
+                if (   enmState == kSingleQ
+                    || (ch2 = *pszString) == '\0'
+                    || (enmState == kDoubleQ && strchr("\\$`\"\n", ch2) == NULL) )
+                    *pszDst++ = ch;
+                else
+                {
+                    *pszDst++ = ch2;
+                    pszString++;
+                }
+                break;
+            }
+
+            case '"':
+                if (enmState == kSingleQ)
+                    *pszDst++ = ch;
+                else
+                    enmState = enmState == kPlain ? kDoubleQ : kPlain;
+                break;
+
+            case '\'':
+                if (enmState == kDoubleQ)
+                    *pszDst++ = ch;
+                else
+                    enmState = enmState == kPlain ? kSingleQ : kPlain;
+                break;
+
+            case '\n':
+                if (enmState == kPlain)
+                {
+                    *pszDst = '\0';
+                    return pszString;
+                }
+                *pszDst++ = ch;
+                break;
+
+            case '=':
+                if (enmState == kPlain && pfStoppedOnEqual)
+                {
+                    *pszDst = '\0';
+                    *pfStoppedOnEqual = true;
+                    return pszString;
+                }
+                *pszDst++ = ch;
+                break;
+
+            case '\0':
+                Assert(enmState == kPlain);
+                *pszDst = '\0';
+                return pszString - 1;
+        }
+    }
+}
+
+
+/**
+ * Worker for rtProcPosixProfileEnvRunAndHarvest that parses the environment
+ * dump and loads it into hEnvToUse.
+ *
+ * @note    This isn't entirely correct should any of the profile setup scripts
+ *          unset any of the environment variables in the basic initial
+ *          enviornment, but since that's unlikely and it's very convenient to
+ *          have something half sensible as a basis if don't don't grok the dump
+ *          entirely and would skip central stuff like PATH or HOME.
+ *
+ * @returns IPRT status code.
+ * @retval  -VERR_PARSE_ERROR (positive, e.g. warning) if we run into trouble.
+ * @retval  -VERR_INVALID_UTF8_ENCODING (positive, e.g. warning) if there are
+ *          invalid UTF-8 in the environment.  This isn't unlikely if the
+ *          profile doesn't use UTF-8.  This is unfortunately not something we
+ *          can guess to accurately up front, so we don't do any guessing and
+ *          hope everyone is sensible and use UTF-8.
+ *
+ * @param   hEnvToUse       The basic environment to extend with what we manage
+ *                          to parse here.
+ * @param   pszEnvDump      The environment dump to parse.  Nominally in Bourne
+ *                          shell 'export -p' format.
+ * @param   fWithMarkers    Whether there are markers around the dump (C shell,
+ *                          tmux) or not.
+ */
+static int rtProcPosixProfileEnvHarvest(RTENV hEnvToUse, char *pszEnvDump, bool fWithMarkers)
+{
+    LogRel3(("**** pszEnvDump start ****\n%s**** pszEnvDump end ****\n", pszEnvDump));
+    if (!LogIs3Enabled())
+        LogFunc(("**** pszEnvDump start ****\n%s**** pszEnvDump end ****\n", pszEnvDump));
+
+    /*
+     * Clip dump at markers if we're using them (C shell).
+     */
+    if (fWithMarkers)
+    {
+        char *pszStart = strstr(pszEnvDump, g_szEnvMarkerBegin);
+        AssertReturn(pszStart, -VERR_PARSE_ERROR);
+        pszStart += sizeof(g_szEnvMarkerBegin) - 1;
+        if (*pszStart == '\n')
+            pszStart++;
+        pszEnvDump = pszStart;
+
+        char *pszEnd = strstr(pszStart, g_szEnvMarkerEnd);
+        AssertReturn(pszEnd, -VERR_PARSE_ERROR);
+        *pszEnd = '\0';
+    }
+
+    /*
+     * Since we're using /bin/sh -c "export -p" for all the dumping, we should
+     * always get lines on the format:
+     *     export VAR1="Value 1"
+     *     export VAR2=Value2
+     *
+     * However, just in case something goes wrong, like bash doesn't think it
+     * needs to be posixly correct, try deal with the alternative where
+     * "declare -x " replaces the "export".
+     */
+    const char *pszPrefix;
+    if (   strncmp(pszEnvDump, RT_STR_TUPLE("export")) == 0
+        && RT_C_IS_BLANK(pszEnvDump[6]))
+        pszPrefix = "export ";
+    else if (   strncmp(pszEnvDump, RT_STR_TUPLE("declare")) == 0
+             && RT_C_IS_BLANK(pszEnvDump[7])
+             && pszEnvDump[8] == '-')
+        pszPrefix = "declare -x "; /* We only need to care about the non-array, non-function lines. */
+    else
+        AssertFailedReturn(-VERR_PARSE_ERROR);
+    size_t const cchPrefix = strlen(pszPrefix);
+
+    /*
+     * Process the lines, ignoring stuff which we don't grok.
+     * The shell should quote problematic characters. Bash double quotes stuff
+     * by default, whereas almquist's shell does it as needed and only the value
+     * side.
+     */
+    int rc = VINF_SUCCESS;
+    while (pszEnvDump && *pszEnvDump != '\0')
+    {
+        /*
+         * Skip the prefixing command.
+         */
+        if (   cchPrefix == 0
+            || strncmp(pszEnvDump, pszPrefix, cchPrefix) == 0)
+        {
+            pszEnvDump += cchPrefix;
+            while (RT_C_IS_BLANK(*pszEnvDump))
+                pszEnvDump++;
+        }
+        else
+        {
+            /* Oops, must find our bearings for some reason... */
+            pszEnvDump = strchr(pszEnvDump, '\n');
+            rc = -VERR_PARSE_ERROR;
+            continue;
+        }
+
+        /*
+         * Parse out the variable name using typical bourne shell escaping
+         * and quoting rules.
+         */
+        /** @todo We should throw away lines that aren't propertly quoted, now we
+         *        just continue and use what we found. */
+        const char *pszVar               = pszEnvDump;
+        bool        fStoppedOnPlainEqual = false;
+        pszEnvDump = rtProcPosixProfileEnvUnquoteAndUnescapeString(pszEnvDump, &fStoppedOnPlainEqual);
+        const char *pszValue             = pszEnvDump;
+        if (fStoppedOnPlainEqual)
+            pszEnvDump = rtProcPosixProfileEnvUnquoteAndUnescapeString(pszEnvDump, NULL /*pfStoppedOnPlainEqual*/);
+        else
+            pszValue = "";
+
+        /*
+         * Add them if valid UTF-8, otherwise we simply drop them for now.
+         * The whole codeset stuff goes seriously wonky here as the environment
+         * we're harvesting probably contains it's own LC_CTYPE or LANG variables,
+         * so ignore the problem for now.
+         */
+        if (   RTStrIsValidEncoding(pszVar)
+            && RTStrIsValidEncoding(pszValue))
+        {
+            int rc2 = RTEnvSetEx(hEnvToUse, pszVar, pszValue);
+            AssertRCReturn(rc2, rc2);
+        }
+        else if (rc == VINF_SUCCESS)
+            rc = -VERR_INVALID_UTF8_ENCODING;
+    }
+
+    return rc;
+}
+
+
+/**
+ * Runs the user's shell in login mode with some environment dumping logic and
+ * harvests the dump, putting it into hEnvToUse.
+ *
+ * This is a bit hairy, esp. with regards to codesets.
+ *
+ * @returns IPRT status code.  Not all error statuses will be returned and the
+ *          caller should just continue with whatever is in hEnvToUse.
+ *
+ * @param   hEnvToUse   On input this is the basic user environment, on success
+ *                      in is fleshed out with stuff from the login shell dump.
+ * @param   pszAsUser   The user name for the profile.
+ * @param   uid         The UID corrsponding to @a pszAsUser, ~0 if current user.
+ * @param   gid         The GID corrsponding to @a pszAsUser, ~0 if current user.
+ * @param   pszShell    The login shell.  This is a writable string to avoid
+ *                      needing to make a copy of it when examining the path
+ *                      part, instead we make a temporary change to it which is
+ *                      always reverted before returning.
+ */
+static int rtProcPosixProfileEnvRunAndHarvest(RTENV hEnvToUse, const char *pszAsUser, uid_t uid, gid_t gid, char *pszShell)
+{
+    LogFlowFunc(("pszAsUser=%s uid=%u gid=%u pszShell=%s; hEnvToUse contains %u variables on entry\n",
+                 pszAsUser, uid, gid, pszShell, RTEnvCountEx(hEnvToUse) ));
+
+    /*
+     * The three standard handles should be pointed to /dev/null, the 3rd handle
+     * is used to dump the environment.
+     */
+    RTPIPE hPipeR, hPipeW;
+    int rc = RTPipeCreate(&hPipeR, &hPipeW, 0);
+    if (RT_SUCCESS(rc))
+    {
+        RTFILE hFileNull;
+        rc = RTFileOpenBitBucket(&hFileNull, RTFILE_O_READWRITE);
+        if (RT_SUCCESS(rc))
+        {
+            int aRedirFds[4];
+            aRedirFds[0] = aRedirFds[1] = aRedirFds[2] = RTFileToNative(hFileNull);
+            aRedirFds[3] = RTPipeToNative(hPipeW);
+
+            /*
+             * Allocate a buffer for receiving the environment dump.
+             *
+             * This is fixed sized for simplicity and safety (creative user script
+             * shouldn't be allowed to exhaust our memory or such, after all we're
+             * most likely running with root privileges in this code path).
+             */
+            size_t const  cbEnvDump  = _64K;
+            char  * const pszEnvDump = (char *)RTMemTmpAllocZ(cbEnvDump);
+            if (pszEnvDump)
+            {
+                /*
+                 * Our default approach is using /bin/sh:
+                 */
+                const char *pszExec = _PATH_BSHELL;
+                const char *apszArgs[8];
+                apszArgs[0] = "-sh";        /* First arg must start with a dash for login shells. */
+                apszArgs[1] = "-c";
+                apszArgs[2] = "POSIXLY_CORRECT=1;export -p >&3";
+                apszArgs[3] = NULL;
+
+                /*
+                 * But see if we can trust the shell to be a real usable shell.
+                 * This would be great as different shell typically has different profile setup
+                 * files and we'll endup with the wrong enviornment if we use a different shell.
+                 */
+                char        szDashShell[32];
+                char        szExportArg[128];
+                bool        fWithMarkers = false;
+                const char *pszShellNm   = RTPathFilename(pszShell);
+                if (   pszShellNm
+                    && access(pszShellNm, X_OK))
+                {
+                    /*
+                     * First the check that it's a known bin directory:
+                     */
+                    size_t const cchShellPath = pszShellNm - pszShell;
+                    char const   chSaved = pszShell[cchShellPath - 1];
+                    pszShell[cchShellPath - 1] = '\0';
+                    if (   RTPathCompare(pszShell, "/bin") == 0
+                        || RTPathCompare(pszShell, "/usr/bin") == 0
+                        || RTPathCompare(pszShell, "/usr/local/bin") == 0)
+                    {
+                        /*
+                         * Then see if we recognize the shell name.
+                         */
+                        RTStrCopy(&szDashShell[1], sizeof(szDashShell) - 1, pszShellNm);
+                        szDashShell[0] = '-';
+                        if (   strcmp(pszShellNm, "bash") == 0
+                            || strcmp(pszShellNm, "ksh") == 0
+                            || strcmp(pszShellNm, "ksh93") == 0
+                            || strcmp(pszShellNm, "zsh") == 0
+                            || strcmp(pszShellNm, "fish") == 0)
+                        {
+                            pszExec      = pszShell;
+                            apszArgs[0]  = szDashShell;
+
+                            /* Use /bin/sh for doing the environment dumping so we get the same kind
+                               of output from everyone and can limit our parsing + testing efforts. */
+                            RTStrPrintf(szExportArg, sizeof(szExportArg),
+                                        "%s -c 'POSIXLY_CORRECT=1;export -p >&3'", _PATH_BSHELL);
+                            apszArgs[2]  = szExportArg;
+                        }
+                        /* C shell is very annoying in that it closes fd 3 without regard to what
+                           we might have put there, so we must use stdout here but with markers so
+                           we can find the dump.
+                           Seems tmux have similar issues as it doesn't work above, but works fine here. */
+                        else if (   strcmp(pszShellNm, "csh") == 0
+                                 || strcmp(pszShellNm, "tcsh") == 0
+                                 || strcmp(pszShellNm, "tmux") == 0)
+                        {
+                            pszExec      = pszShell;
+                            apszArgs[0]  = szDashShell;
+
+                            fWithMarkers = true;
+                            size_t cch = RTStrPrintf(szExportArg, sizeof(szExportArg),
+                                                     "%s -c 'set -e;POSIXLY_CORRECT=1;echo %s;export -p;echo %s'",
+                                                     _PATH_BSHELL, g_szEnvMarkerBegin, g_szEnvMarkerEnd);
+                            Assert(cch < sizeof(szExportArg) - 1); RT_NOREF(cch);
+                            apszArgs[2]  = szExportArg;
+
+                            aRedirFds[1] = aRedirFds[3];
+                            aRedirFds[3] = -1;
+                        }
+                    }
+                    pszShell[cchShellPath - 1] = chSaved;
+                }
+
+                /*
+                 * Create the process and wait for the output.
+                 */
+                LogFunc(("Executing '%s': '%s', '%s', '%s'\n", pszExec, apszArgs[0], apszArgs[1], apszArgs[2]));
+                RTPROCESS hProcess = NIL_RTPROCESS;
+                rc = rtProcPosixCreateInner(pszExec, apszArgs, hEnvToUse, hEnvToUse, 0 /*fFlags*/,
+                                            pszAsUser, uid, gid, RT_ELEMENTS(aRedirFds), aRedirFds, &hProcess);
+                if (RT_SUCCESS(rc))
+                {
+                    RTPipeClose(hPipeW);
+                    hPipeW = NIL_RTPIPE;
+
+                    size_t         offEnvDump = 0;
+                    uint64_t const msStart    = RTTimeMilliTS();
+                    for (;;)
+                    {
+                        size_t cbRead = 0;
+                        if (offEnvDump < cbEnvDump - 1)
+                        {
+                            rc = RTPipeRead(hPipeR, &pszEnvDump[offEnvDump], cbEnvDump - 1 - offEnvDump, &cbRead);
+                            if (RT_SUCCESS(rc))
+                                offEnvDump += cbRead;
+                            else
+                            {
+                                LogFlowFunc(("Breaking out of read loop: %Rrc\n", rc));
+                                if (rc == VERR_BROKEN_PIPE)
+                                    rc = VINF_SUCCESS;
+                                break;
+                            }
+                            pszEnvDump[offEnvDump] = '\0';
+                        }
+                        else
+                        {
+                            LogFunc(("Too much data in environment dump, dropping it\n"));
+                            rc = VERR_TOO_MUCH_DATA;
+                            break;
+                        }
+
+                        /* Do the timout check. */
+                        uint64_t const cMsElapsed = RTTimeMilliTS() - msStart;
+                        if (cMsElapsed >= RT_MS_15SEC)
+                        {
+                            LogFunc(("Timed out after %RU64 ms\n", cMsElapsed));
+                            rc = VERR_TIMEOUT;
+                            break;
+                        }
+
+                        /* If we got no data in above wait for more to become ready. */
+                        if (!cbRead)
+                            RTPipeSelectOne(hPipeR, RT_MS_15SEC - cMsElapsed);
+                    }
+
+                    /*
+                     * Kill the process and wait for it to avoid leaving zombies behind.
+                     */
+                    /** @todo do we check the exit code? */
+                    int rc2 = RTProcWait(hProcess, RTPROCWAIT_FLAGS_NOBLOCK, NULL);
+                    if (RT_SUCCESS(rc2))
+                        LogFlowFunc(("First RTProcWait succeeded\n"));
+                    else
+                    {
+                        LogFunc(("First RTProcWait failed (%Rrc), terminating and doing a blocking wait\n", rc2));
+                        RTProcTerminate(hProcess);
+                        RTProcWait(hProcess, RTPROCWAIT_FLAGS_BLOCK, NULL);
+                    }
+
+                    /*
+                     * Parse the result.
+                     */
+                    if (RT_SUCCESS(rc))
+                        rc = rtProcPosixProfileEnvHarvest(hEnvToUse, pszEnvDump, fWithMarkers);
+                    else
+                    {
+                        LogFunc(("Ignoring rc=%Rrc from the pipe read loop and continues with basic environment\n", rc));
+                        rc = -rc;
+                    }
+                }
+                else
+                    LogFunc(("Failed to create process '%s': %Rrc\n", pszExec, rc));
+                RTMemTmpFree(pszEnvDump);
+            }
+            else
+            {
+                LogFunc(("Failed to allocate %#zx bytes for the dump\n", cbEnvDump));
+                rc = VERR_NO_TMP_MEMORY;
+            }
+            RTFileClose(hFileNull);
+        }
+        else
+            LogFunc(("Failed to open /dev/null: %Rrc\n", rc));
+        RTPipeClose(hPipeR);
+        RTPipeClose(hPipeW);
+    }
+    else
+        LogFunc(("Failed to create pipe: %Rrc\n", rc));
+    LogFlowFunc(("returns %Rrc (hEnvToUse contains %u variables now)\n", rc, RTEnvCountEx(hEnvToUse)));
+    return rc;
+}
+
+
+/**
+ * Create an environment for the given user.
+ *
+ * This starts by creating a very basic environment and then tries to do it
+ * properly by running the user's shell in login mode with some environment
+ * dumping attached.  The latter may fail and we'll ignore that for now and move
+ * ahead with the very basic environment.
+ *
+ * @returns IPRT status code.
+ * @param   phEnvToUse  Where to return the created environment.
+ * @param   pszAsUser   The user name for the profile.  NULL if the current
+ *                      user.
+ * @param   uid         The UID corrsponding to @a pszAsUser, ~0 if NULL.
+ * @param   gid         The GID corrsponding to @a pszAsUser, ~0 if NULL.
+ * @param   fFlags      RTPROC_FLAGS_XXX
+ * @param   papszPamEnv Array of environment variables returned by PAM, if
+ *                      it was used for authentication and produced anything.
+ *                      Otherwise NULL.
+ */
+static int rtProcPosixCreateProfileEnv(PRTENV phEnvToUse, const char *pszAsUser, uid_t uid, gid_t gid,
+                                       uint32_t fFlags, char **papszPamEnv)
+{
+    /*
+     * Get the passwd entry for the user.
+     */
+    struct passwd   Pwd;
+    struct passwd  *pPwd = NULL;
+    char            achBuf[_4K];
+    int             rc;
+    errno = 0;
+    if (pszAsUser)
+        rc = getpwnam_r(pszAsUser, &Pwd, achBuf, sizeof(achBuf), &pPwd);
+    else
+        rc = getpwuid_r(getuid(), &Pwd, achBuf, sizeof(achBuf), &pPwd);
+    if (rc == 0 && pPwd)
+    {
+        /*
+         * Convert stuff to UTF-8 since the environment is UTF-8.
+         */
+        char *pszDir;
+        rc = RTStrCurrentCPToUtf8(&pszDir, pPwd->pw_dir);
+        if (RT_SUCCESS(rc))
+        {
+#if 0 /* Enable and modify this to test shells other that your login shell. */
+            pPwd->pw_shell = (char *)"/bin/tmux";
+#endif
+            char *pszShell;
+            rc = RTStrCurrentCPToUtf8(&pszShell, pPwd->pw_shell);
+            if (RT_SUCCESS(rc))
+            {
+                char *pszAsUserFree = NULL;
+                if (!pszAsUser)
+                {
+                    rc = RTStrCurrentCPToUtf8(&pszAsUserFree, pPwd->pw_name);
+                    if (RT_SUCCESS(rc))
+                        pszAsUser = pszAsUserFree;
+                }
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * Create and populate the environment.
+                     */
+                    rc = RTEnvCreate(phEnvToUse);
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTENV hEnvToUse = *phEnvToUse;
+                        rc = RTEnvSetEx(hEnvToUse, "HOME", pszDir);
+                        if (RT_SUCCESS(rc))
+                            rc = RTEnvSetEx(hEnvToUse, "SHELL", pszShell);
+                        if (RT_SUCCESS(rc))
+                            rc = RTEnvSetEx(hEnvToUse, "USER", pszAsUser);
+                        if (RT_SUCCESS(rc))
+                            rc = RTEnvSetEx(hEnvToUse, "LOGNAME", pszAsUser);
+                        if (RT_SUCCESS(rc))
+                            rc = RTEnvSetEx(hEnvToUse, "PATH", pPwd->pw_uid == 0 ? _PATH_STDPATH : _PATH_DEFPATH);
+                        char szTmpPath[RTPATH_MAX];
+                        if (RT_SUCCESS(rc))
+                        {
+                            RTStrPrintf(szTmpPath, sizeof(szTmpPath), "%s/%s", _PATH_MAILDIR, pszAsUser);
+                            rc = RTEnvSetEx(hEnvToUse, "MAIL", szTmpPath);
+                        }
+#ifdef RT_OS_DARWIN
+                        if (RT_SUCCESS(rc))
+                        {
+                            /* TMPDIR is some unique per user directory under /var/folders on darwin,
+                               so get the one for the current user.  If we're launching the process as
+                               a different user, rtProcPosixAdjustProfileEnvFromChild will update it
+                               again for the actual child process user (provided we set it here). See
+                               https://opensource.apple.com/source/Libc/Libc-997.1.1/darwin/_dirhelper.c
+                               for the implementation of this query. */
+                            size_t cbNeeded = confstr(_CS_DARWIN_USER_TEMP_DIR, szTmpPath, sizeof(szTmpPath));
+                            if (cbNeeded > 0 && cbNeeded < sizeof(szTmpPath))
+                            {
+                                char *pszTmp;
+                                rc = RTStrCurrentCPToUtf8(&pszTmp, szTmpPath);
+                                if (RT_SUCCESS(rc))
+                                {
+                                    rc = RTEnvSetEx(hEnvToUse, "TMPDIR", pszTmp);
+                                    RTStrFree(pszTmp);
+                                }
+                            }
+                            else
+                                rc = VERR_BUFFER_OVERFLOW;
+                        }
+#endif
+                        /*
+                         * Add everything from the PAM environment.
+                         */
+                        if (RT_SUCCESS(rc) && papszPamEnv != NULL)
+                            for (size_t i = 0; papszPamEnv[i] != NULL && RT_SUCCESS(rc); i++)
+                            {
+                                char *pszEnvVar;
+                                rc = RTStrCurrentCPToUtf8(&pszEnvVar, papszPamEnv[i]);
+                                if (RT_SUCCESS(rc))
+                                {
+                                    char *pszValue = strchr(pszEnvVar, '=');
+                                    if (pszValue)
+                                        *pszValue++ = '\0';
+                                    rc = RTEnvSetEx(hEnvToUse, pszEnvVar, pszValue ? pszValue : "");
+                                    RTStrFree(pszEnvVar);
+                                }
+                                /* Ignore conversion issue, though LogRel them. */
+                                else if (rc != VERR_NO_STR_MEMORY && rc != VERR_NO_MEMORY)
+                                {
+                                    LogRelMax(256, ("RTStrCurrentCPToUtf8(,%.*Rhxs) -> %Rrc\n", strlen(pszEnvVar), pszEnvVar, rc));
+                                    rc = -rc;
+                                }
+                            }
+                        if (RT_SUCCESS(rc))
+                        {
+                            /*
+                             * Now comes the fun part where we need to try run a shell in login mode
+                             * and harvest its final environment to get the proper environment for
+                             * the user.  We ignore some failures here so buggy login scrips and
+                             * other weird stuff won't trip us up too badly.
+                             */
+                            if (!(fFlags & RTPROC_FLAGS_ONLY_BASIC_PROFILE))
+                                rc = rtProcPosixProfileEnvRunAndHarvest(hEnvToUse, pszAsUser, uid, gid, pszShell);
+                        }
+
+                        if (RT_FAILURE(rc))
+                            RTEnvDestroy(hEnvToUse);
+                    }
+                    RTStrFree(pszAsUserFree);
+                }
+                RTStrFree(pszShell);
+            }
+            RTStrFree(pszDir);
+        }
+    }
+    else
+        rc = errno ? RTErrConvertFromErrno(errno) : VERR_ACCESS_DENIED;
+    return rc;
+}
+
+
+/**
+ * Converts the arguments to the child's LC_CTYPE charset if necessary.
+ *
+ * @returns IPRT status code.
+ * @param   papszArgs   The arguments (UTF-8).
+ * @param   hEnvToUse   The child process environment.
+ * @param   ppapszArgs  Where to return the converted arguments.  The array
+ *                      entries must be freed by RTStrFree and the array itself
+ *                      by RTMemFree.
+ */
+static int rtProcPosixConvertArgv(const char * const *papszArgs, RTENV hEnvToUse, char ***ppapszArgs)
+{
+    *ppapszArgs = (char **)papszArgs;
+
+    /*
+     * The first thing we need to do here is to try guess the codeset of the
+     * child process and check if it's UTF-8 or not.
+     */
+    const char *pszEncoding;
+    char        szEncoding[512];
+    if (hEnvToUse == RTENV_DEFAULT)
+    {
+        /* Same environment as us, assume setlocale is up to date: */
+        pszEncoding = rtStrGetLocaleCodeset();
+    }
+    else
+    {
+        /*
+         * LC_ALL overrides everything else.  The LC_* environment variables are often set
+         * to the empty string so move on the next variable if that is the case (that's
+         * what setlocale in glibc does).
+         */
+        const char *pszVar;
+        int rc = RTEnvGetEx(hEnvToUse, pszVar = "LC_ALL", szEncoding, sizeof(szEncoding), NULL);
+        if (rc == VERR_ENV_VAR_NOT_FOUND || (RT_SUCCESS(rc) && szEncoding[0] == '\0'))
+            rc = RTEnvGetEx(hEnvToUse, pszVar = "LC_CTYPE", szEncoding, sizeof(szEncoding), NULL);
+        if (rc == VERR_ENV_VAR_NOT_FOUND || (RT_SUCCESS(rc) && szEncoding[0] == '\0'))
+            rc = RTEnvGetEx(hEnvToUse, pszVar = "LANG", szEncoding, sizeof(szEncoding), NULL);
+        if (RT_SUCCESS(rc) && szEncoding[0] != '\0')
+        {
+            /*
+             * LC_ALL can contain a composite locale consisting of the locales of each of the
+             * categories in two different formats depending on the OS. On Solaris, macOS, and
+             * *BSD composite locale names use slash ('/') as the separator and the following
+             * order for the categories:
+             *   LC_CTYPE/LC_NUMERIC/LC_TIME/LC_COLLATE/LC_MONETARY/LC_MESSAGES
+             * e.g.:
+             *   en_US.UTF-8/POSIX/el_GR.UTF-8/el_CY.UTF-8/en_GB.UTF-8/es_ES.UTF-8
+             *
+             * On Solaris there is also a leading slash.
+             *
+             * On Linux and OS/2 the composite locale format is made up of key-value pairs
+             * of category names and locales of the form 'name=value' with each element
+             * separated by a semicolon in the same order as above with following additional
+             * categories included as well:
+             *   LC_PAPER/LC_NAME/LC_ADDRESS/LC_TELEPHONE/LC_MEASUREMENT/LC_IDENTIFICATION
+             * e.g.
+             *   LC_CTYPE=fr_BE;LC_NUMERIC=fr_BE@euro;LC_TIME=fr_BE.utf8;LC_COLLATE=fr_CA;\
+             *   LC_MONETARY=fr_CA.utf8;LC_MESSAGES=fr_CH;LC_PAPER=fr_CH.utf8;LC_NAME=fr_FR;\
+             *   LC_ADDRESS=fr_FR.utf8;LC_TELEPHONE=fr_LU;LC_MEASUREMENT=fr_LU@euro;\
+             *   LC_IDENTIFICATION=fr_LU.utf8
+             */
+            char *pszEncodingStart = szEncoding;
+#if !defined(RT_OS_LINUX) && !defined(RT_OS_OS2)
+            if (*pszEncodingStart == '/')
+                pszEncodingStart++;
+            char *pszSlash = strchr(pszEncodingStart, '/');
+            if (pszSlash)
+                *pszSlash = '\0';       /* This ASSUMES the first one is LC_CTYPE! */
+#else
+            char *pszCType = strstr(pszEncodingStart, "LC_CTYPE=");
+            if (pszCType)
+            {
+                pszEncodingStart = pszCType + sizeof("LC_CTYPE=") - 1;
+
+                char *pszSemiColon = strchr(pszEncodingStart, ';');
+                if (pszSemiColon)
+                    *pszSemiColon = '\0';
+            }
+#endif
+
+            /*
+             * Use newlocale and nl_langinfo_l to determine the default codeset for the locale
+             * specified in the child's environment.  These routines have been around since
+             * ancient days on Linux and for quite a long time on macOS, Solaris, and *BSD but
+             * to ensure their availability check that LC_CTYPE_MASK is defined.
+             *
+             * Note! The macOS nl_langinfo(3)/nl_langinfo_l(3) routines return a pointer to an
+             *       empty string for "short" locale names like en_NZ, it_IT, el_GR, etc. so use
+             *       UTF-8 in those cases as it is the default for short name locales on macOS
+             *       (see also rtStrGetLocaleCodeset).
+             */
+#ifdef LC_CTYPE_MASK
+            locale_t hLocale = newlocale(LC_CTYPE_MASK, pszEncodingStart, (locale_t)0);
+            if (hLocale != (locale_t)0)
+            {
+                const char *pszCodeset = nl_langinfo_l(CODESET, hLocale);
+                Log2Func(("nl_langinfo_l(CODESET, %s=%s) -> %s\n", pszVar, pszEncodingStart, pszCodeset));
+                if (!pszCodeset || *pszCodeset == '\0')
+# ifdef RT_OS_DARWIN
+                    pszEncoding = "UTF-8";
+# else
+                    pszEncoding = "ASCII";
+# endif
+                else
+                {
+                    rc = RTStrCopy(szEncoding, sizeof(szEncoding), pszCodeset);
+                    AssertRC(rc); /* cannot possibly overflow */
+                }
+
+                freelocale(hLocale);
+                pszEncoding = szEncoding;
+             }
+             else
+#endif
+             {
+                 /* If there is something that ought to be a character set encoding, try use it: */
+                 const char *pszDot = strchr(pszEncodingStart, '.');
+                 if (pszDot)
+                     pszDot = RTStrStripL(pszDot + 1);
+                 if (pszDot && *pszDot != '\0')
+                 {
+                     pszEncoding = pszDot;
+                     Log2Func(("%s=%s -> %s (simple)\n", pszVar, szEncoding, pszEncoding));
+                 }
+                 else
+                 {
+                     /* This is mostly wrong, but I cannot think of anything better now: */
+                     pszEncoding = rtStrGetLocaleCodeset();
+                     LogFunc(("No newlocale or it failed (on '%s=%s', errno=%d), falling back on %s that we're using...\n",
+                              pszVar, pszEncodingStart, errno, pszEncoding));
+                 }
+             }
+             RT_NOREF_PV(pszVar);
+        }
+        else
+#ifdef RT_OS_DARWIN /* @bugref{10153}: Darwin defaults to UTF-8. */
+            pszEncoding = "UTF-8";
+#else
+            pszEncoding = "ASCII";
+#endif
+    }
+
+    /*
+     * Do nothing if it's UTF-8.
+     */
+    if (rtStrIsCodesetUtf8(pszEncoding))
+    {
+        LogFlowFunc(("No conversion needed (%s)\n", pszEncoding));
+        return VINF_SUCCESS;
+    }
+
+
+    /*
+     * Do the conversion.
+     */
+    size_t cArgs = 0;
+    while (papszArgs[cArgs] != NULL)
+        cArgs++;
+    LogFunc(("Converting #%u arguments to %s...\n", cArgs, pszEncoding));
+
+    char **papszArgsConverted = (char **)RTMemAllocZ(sizeof(papszArgsConverted[0]) * (cArgs + 2));
+    AssertReturn(papszArgsConverted, VERR_NO_MEMORY);
+
+    void *pvConversionCache = NULL;
+    rtStrLocalCacheInit(&pvConversionCache);
+    for (size_t i = 0; i < cArgs; i++)
+    {
+        int rc = rtStrLocalCacheConvert(papszArgs[i], strlen(papszArgs[i]), "UTF-8",
+                                        &papszArgsConverted[i], 0, pszEncoding, &pvConversionCache);
+        if (RT_SUCCESS(rc) && rc != VWRN_NO_TRANSLATION)
+        { /* likely */ }
+        else
+        {
+            LogRelMax(100, ("Failed to convert argument #%u '%s' to '%s': %Rrc\n", i, papszArgs[i], pszEncoding, rc));
+            while (i-- > 0)
+                RTStrFree(papszArgsConverted[i]);
+            RTMemFree(papszArgsConverted);
+            rtStrLocalCacheDelete(&pvConversionCache);
+            return rc == VWRN_NO_TRANSLATION || rc == VERR_NO_TRANSLATION ? VERR_PROC_NO_ARG_TRANSLATION : rc;
+        }
+    }
+
+    rtStrLocalCacheDelete(&pvConversionCache);
+    *ppapszArgs = papszArgsConverted;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The result structure for rtPathFindExec/RTPathTraverseList.
+ * @todo move to common path code?
+ */
+typedef struct RTPATHINTSEARCH
+{
+    /** For EACCES or EPERM errors that we continued on.
+     * @note Must be initialized to VINF_SUCCESS. */
+    int  rcSticky;
+    /** Buffer containing the filename. */
+    char szFound[RTPATH_MAX];
+} RTPATHINTSEARCH;
+/** Pointer to a rtPathFindExec/RTPathTraverseList result. */
+typedef RTPATHINTSEARCH *PRTPATHINTSEARCH;
+
+
+/**
+ * RTPathTraverseList callback used by RTProcCreateEx to locate the executable.
+ */
+static DECLCALLBACK(int) rtPathFindExec(char const *pchPath, size_t cchPath, void *pvUser1, void *pvUser2)
+{
+    const char      *pszExec = (const char *)pvUser1;
+    PRTPATHINTSEARCH pResult = (PRTPATHINTSEARCH)pvUser2;
+    int rc = RTPathJoinEx(pResult->szFound, sizeof(pResult->szFound), pchPath, cchPath, pszExec, RTSTR_MAX,
+                          RTPATH_STR_F_STYLE_HOST);
+    if (RT_SUCCESS(rc))
+    {
+        const char *pszNativeExec = NULL;
+        rc = rtPathToNative(&pszNativeExec, pResult->szFound, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            if (!access(pszNativeExec, X_OK))
+                rc = VINF_SUCCESS;
+            else
+            {
+                if (   errno == EACCES
+                    || errno == EPERM)
+                    pResult->rcSticky = RTErrConvertFromErrno(errno);
+                rc = VERR_TRY_AGAIN;
+            }
+            rtPathFreeNative(pszNativeExec, pResult->szFound);
+        }
+        else
+            AssertRCStmt(rc, rc = VERR_TRY_AGAIN /* don't stop on this, whatever it is */);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int)   RTProcCreateEx(const char *pszExec, const char * const *papszArgs, RTENV hEnv, uint32_t fFlags,
+                               PCRTHANDLE phStdIn, PCRTHANDLE phStdOut, PCRTHANDLE phStdErr, const char *pszAsUser,
+                               const char *pszPassword, void *pvExtraData, PRTPROCESS phProcess)
+{
+    int rc;
+    LogFlow(("RTProcCreateEx: pszExec=%s pszAsUser=%s fFlags=%#x phStdIn=%p phStdOut=%p phStdErr=%p\n",
+             pszExec, pszAsUser, fFlags, phStdIn, phStdOut, phStdErr));
+
+    /*
+     * Input validation
+     */
+    AssertPtrReturn(pszExec, VERR_INVALID_POINTER);
+    AssertReturn(*pszExec, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTPROC_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & RTPROC_FLAGS_DETACHED) || !phProcess, VERR_INVALID_PARAMETER);
+    AssertReturn(hEnv != NIL_RTENV, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(papszArgs, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pszAsUser, VERR_INVALID_POINTER);
+    AssertReturn(!pszAsUser || *pszAsUser, VERR_INVALID_PARAMETER);
+    AssertReturn(!pszPassword || pszAsUser, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pszPassword, VERR_INVALID_POINTER);
+#if defined(RT_OS_OS2)
+    if (fFlags & RTPROC_FLAGS_DETACHED)
+        return VERR_PROC_DETACH_NOT_SUPPORTED;
+#endif
+    AssertReturn(pvExtraData == NULL || (fFlags & RTPROC_FLAGS_DESIRED_SESSION_ID), VERR_INVALID_PARAMETER);
+
+    /*
+     * Get the file descriptors for the handles we've been passed.
+     */
+    PCRTHANDLE  paHandles[3] = { phStdIn, phStdOut, phStdErr };
+    int         aStdFds[3]   = {      -1,       -1,       -1 };
+    for (int i = 0; i < 3; i++)
+    {
+        if (paHandles[i])
+        {
+            AssertPtrReturn(paHandles[i], VERR_INVALID_POINTER);
+            switch (paHandles[i]->enmType)
+            {
+                case RTHANDLETYPE_FILE:
+                    aStdFds[i] = paHandles[i]->u.hFile != NIL_RTFILE
+                               ? (int)RTFileToNative(paHandles[i]->u.hFile)
+                               : -2 /* close it */;
+                    break;
+
+                case RTHANDLETYPE_PIPE:
+                    aStdFds[i] = paHandles[i]->u.hPipe != NIL_RTPIPE
+                               ? (int)RTPipeToNative(paHandles[i]->u.hPipe)
+                               : -2 /* close it */;
+                    break;
+
+                case RTHANDLETYPE_SOCKET:
+                    aStdFds[i] = paHandles[i]->u.hSocket != NIL_RTSOCKET
+                               ? (int)RTSocketToNative(paHandles[i]->u.hSocket)
+                               : -2 /* close it */;
+                    break;
+
+                default:
+                    AssertMsgFailedReturn(("%d: %d\n", i, paHandles[i]->enmType), VERR_INVALID_PARAMETER);
+            }
+            /** @todo check the close-on-execness of these handles?  */
+        }
+    }
+
+    for (int i = 0; i < 3; i++)
+        if (aStdFds[i] == i)
+            aStdFds[i] = -1;
+    LogFlowFunc(("aStdFds={%d, %d, %d}\n", aStdFds[0], aStdFds[1], aStdFds[2]));
+
+    for (int i = 0; i < 3; i++)
+        AssertMsgReturn(aStdFds[i] < 0 || aStdFds[i] > i,
+                        ("%i := %i not possible because we're lazy\n", i, aStdFds[i]),
+                        VERR_NOT_SUPPORTED);
+
+    /*
+     * Validate the credentials if a user is specified.
+     */
+    bool const  fNeedLoginEnv = (fFlags & RTPROC_FLAGS_PROFILE)
+                             && ((fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD) || hEnv == RTENV_DEFAULT);
+    uid_t       uid           = ~(uid_t)0;
+    gid_t       gid           = ~(gid_t)0;
+    char      **papszPamEnv   = NULL;
+    if (pszAsUser)
+    {
+        rc = rtCheckCredentials(pszAsUser, pszPassword, &gid, &uid, fNeedLoginEnv ? &papszPamEnv : NULL);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+#ifdef IPRT_USE_PAM
+    /*
+     * User unchanged, but if PROFILE is request we must try get the PAM
+     * environmnet variables.
+     *
+     * For this to work, we'll need a special PAM service profile which doesn't
+     * actually do any authentication, only concerns itself with the enviornment
+     * setup.  gdm-launch-environment is such one, and we use it if we haven't
+     * got an IPRT specific one there.
+     */
+    else if (fNeedLoginEnv)
+    {
+        const char *pszService;
+        if (rtProcPosixPamServiceExists("iprt-environment"))
+            pszService = "iprt-environment";
+# ifdef IPRT_PAM_NATIVE_SERVICE_NAME_ENVIRONMENT
+        else if (rtProcPosixPamServiceExists(IPRT_PAM_NATIVE_SERVICE_NAME_ENVIRONMENT))
+            pszService = IPRT_PAM_NATIVE_SERVICE_NAME_ENVIRONMENT;
+# endif
+        else if (rtProcPosixPamServiceExists("gdm-launch-environment"))
+            pszService = "gdm-launch-environment";
+        else
+            pszService = NULL;
+        if (pszService)
+        {
+            char szLoginName[512];
+            rc = getlogin_r(szLoginName, sizeof(szLoginName));
+            if (rc == 0)
+                rc = rtProcPosixAuthenticateUsingPam(pszService, szLoginName, "xxx", &papszPamEnv, NULL);
+        }
+    }
+#endif
+
+    /*
+     * Create the child environment if either RTPROC_FLAGS_PROFILE or
+     * RTPROC_FLAGS_ENV_CHANGE_RECORD are in effect.
+     */
+    RTENV hEnvToUse = hEnv;
+    if (   (fFlags & (RTPROC_FLAGS_ENV_CHANGE_RECORD | RTPROC_FLAGS_PROFILE))
+        && (   (fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)
+            || hEnv == RTENV_DEFAULT) )
+    {
+        if (fFlags & RTPROC_FLAGS_PROFILE)
+            rc = rtProcPosixCreateProfileEnv(&hEnvToUse, pszAsUser, uid, gid, fFlags, papszPamEnv);
+        else
+            rc = RTEnvClone(&hEnvToUse, RTENV_DEFAULT);
+        rtProcPosixFreePamEnv(papszPamEnv);
+        papszPamEnv = NULL;
+        if (RT_FAILURE(rc))
+            return rc;
+
+        if ((fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD) && hEnv != RTENV_DEFAULT)
+        {
+            rc = RTEnvApplyChanges(hEnvToUse, hEnv);
+            if (RT_FAILURE(rc))
+            {
+                RTEnvDestroy(hEnvToUse);
+                return rc;
+            }
+        }
+    }
+    Assert(papszPamEnv == NULL);
+
+    /*
+     * Check for execute access to the file, searching the PATH if needed.
+     */
+    const char *pszNativeExec = NULL;
+    rc = rtPathToNative(&pszNativeExec, pszExec, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        if (access(pszNativeExec, X_OK) == 0)
+            rc = VINF_SUCCESS;
+        else
+        {
+            rc = errno;
+            rtPathFreeNative(pszNativeExec, pszExec);
+
+            if (   !(fFlags & RTPROC_FLAGS_SEARCH_PATH)
+                || rc != ENOENT
+                || RTPathHavePath(pszExec) )
+                rc = RTErrConvertFromErrno(rc);
+            else
+            {
+                /* Search the PATH for it: */
+                char *pszPath = RTEnvDupEx(hEnvToUse, "PATH");
+                if (pszPath)
+                {
+                    PRTPATHINTSEARCH pResult = (PRTPATHINTSEARCH)alloca(sizeof(*pResult));
+                    pResult->rcSticky = VINF_SUCCESS;
+                    rc = RTPathTraverseList(pszPath, ':', rtPathFindExec, (void *)pszExec, pResult);
+                    RTStrFree(pszPath);
+                    if (RT_SUCCESS(rc))
+                    {
+                        /* Found it. Now, convert to native path: */
+                        pszExec = pResult->szFound;
+                        rc = rtPathToNative(&pszNativeExec, pszExec, NULL);
+                    }
+                    else
+                        rc = rc != VERR_END_OF_STRING ? rc
+                           : pResult->rcSticky == VINF_SUCCESS ? VERR_FILE_NOT_FOUND : pResult->rcSticky;
+                }
+                else
+                    rc = VERR_NO_STR_MEMORY;
+            }
+        }
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Convert arguments to child codeset if necessary.
+             */
+            char **papszArgsConverted = (char **)papszArgs;
+            if (!(fFlags & RTPROC_FLAGS_UTF8_ARGV))
+                rc = rtProcPosixConvertArgv(papszArgs, hEnvToUse, &papszArgsConverted);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * The rest of the process creation is reused internally by rtProcPosixCreateProfileEnv.
+                 */
+                rc = rtProcPosixCreateInner(pszNativeExec, papszArgsConverted, hEnv, hEnvToUse, fFlags, pszAsUser, uid, gid,
+                                            RT_ELEMENTS(aStdFds), aStdFds, phProcess);
+
+            }
+
+            /* Free the translated argv copy, if needed. */
+            if (papszArgsConverted != (char **)papszArgs)
+            {
+                for (size_t i = 0; papszArgsConverted[i] != NULL; i++)
+                    RTStrFree(papszArgsConverted[i]);
+                RTMemFree(papszArgsConverted);
+            }
+            rtPathFreeNative(pszNativeExec, pszExec);
+        }
+    }
+    if (hEnvToUse != hEnv)
+        RTEnvDestroy(hEnvToUse);
+    return rc;
+}
+
+
+/**
+ * The inner 2nd half of RTProcCreateEx.
+ *
+ * This is also used by rtProcPosixCreateProfileEnv().
+ *
+ * @returns IPRT status code.
+ * @param   pszNativeExec   The executable to run (absolute path, X_OK).
+ *                          Native path.
+ * @param   papszArgs       The arguments.  Caller has done codeset conversions.
+ * @param   hEnv            The original enviornment request, needed for
+ *                          adjustments if starting as different user.
+ * @param   hEnvToUse       The environment we should use.
+ * @param   fFlags          The process creation flags, RTPROC_FLAGS_XXX.
+ * @param   pszAsUser       The user to start the process as, if requested.
+ * @param   uid             The UID corrsponding to @a pszAsUser, ~0 if NULL.
+ * @param   gid             The GID corrsponding to @a pszAsUser, ~0 if NULL.
+ * @param   cRedirFds       Number of redirection file descriptors.
+ * @param   paRedirFds      Pointer to redirection file descriptors.  Entries
+ *                          containing -1 are not modified (inherit from parent),
+ *                          -2 indicates that the descriptor should be closed in the
+ *                          child.
+ * @param   phProcess       Where to return the process ID on success.
+ */
+static int rtProcPosixCreateInner(const char *pszNativeExec, const char * const *papszArgs, RTENV hEnv, RTENV hEnvToUse,
+                                  uint32_t fFlags, const char *pszAsUser, uid_t uid, gid_t gid,
+                                  unsigned cRedirFds, int *paRedirFds, PRTPROCESS phProcess)
+{
+    /*
+     * Get the environment block.
+     */
+    const char * const *papszEnv = RTEnvGetExecEnvP(hEnvToUse);
+    AssertPtrReturn(papszEnv, VERR_INVALID_HANDLE);
+
+    /*
+     * Optimize the redirections.
+     */
+    while (cRedirFds > 0 && paRedirFds[cRedirFds - 1] == -1)
+        cRedirFds--;
+
+    /*
+     * Child PID.
+     */
+    pid_t pid = -1;
+
+    /*
+     * Take care of detaching the process.
+     *
+     * HACK ALERT! Put the process into a new process group with pgid = pid
+     * to make sure it differs from that of the parent process to ensure that
+     * the IPRT waitpid call doesn't race anyone (read XPCOM) doing group wide
+     * waits. setsid() includes the setpgid() functionality.
+     * 2010-10-11 XPCOM no longer waits for anything, but it cannot hurt.
+     */
+#ifndef RT_OS_OS2
+    if (fFlags & RTPROC_FLAGS_DETACHED)
+    {
+# ifdef RT_OS_SOLARIS
+        int templateFd = -1;
+        if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+        {
+            templateFd = rtSolarisContractPreFork();
+            if (templateFd == -1)
+                return VERR_OPEN_FAILED;
+        }
+# endif /* RT_OS_SOLARIS */
+        pid = fork();
+        if (!pid)
+        {
+# ifdef RT_OS_SOLARIS
+            if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+                rtSolarisContractPostForkChild(templateFd);
+# endif
+            setsid(); /* see comment above */
+
+            pid = -1;
+            /* Child falls through to the actual spawn code below. */
+        }
+        else
+        {
+# ifdef RT_OS_SOLARIS
+            if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+                rtSolarisContractPostForkParent(templateFd, pid);
+# endif
+            if (pid > 0)
+            {
+                /* Must wait for the temporary process to avoid a zombie. */
+                int status = 0;
+                pid_t pidChild = 0;
+
+                /* Restart if we get interrupted. */
+                do
+                {
+                    pidChild = waitpid(pid, &status, 0);
+                } while (   pidChild == -1
+                         && errno == EINTR);
+
+                /* Assume that something wasn't found. No detailed info. */
+                if (status)
+                    return VERR_PROCESS_NOT_FOUND;
+                if (phProcess)
+                    *phProcess = 0;
+                return VINF_SUCCESS;
+            }
+            return RTErrConvertFromErrno(errno);
+        }
+    }
+#endif
+
+    /*
+     * Spawn the child.
+     *
+     * Any spawn code MUST not execute any atexit functions if it is for a
+     * detached process. It would lead to running the atexit functions which
+     * make only sense for the parent. libORBit e.g. gets confused by multiple
+     * execution. Remember, there was only a fork() so far, and until exec()
+     * is successfully run there is nothing which would prevent doing anything
+     * silly with the (duplicated) file descriptors.
+     */
+    int rc;
+#ifdef HAVE_POSIX_SPAWN
+    /** @todo OS/2: implement DETACHED (BACKGROUND stuff), see VbglR3Daemonize.  */
+    if (   uid == ~(uid_t)0
+        && gid == ~(gid_t)0)
+    {
+        /* Spawn attributes. */
+        posix_spawnattr_t Attr;
+        rc = posix_spawnattr_init(&Attr);
+        if (!rc)
+        {
+            /* Indicate that process group and signal mask are to be changed,
+               and that the child should use default signal actions. */
+            rc = posix_spawnattr_setflags(&Attr, POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF);
+            Assert(rc == 0);
+
+            /* The child starts in its own process group. */
+            if (!rc)
+            {
+                rc = posix_spawnattr_setpgroup(&Attr, 0 /* pg == child pid */);
+                Assert(rc == 0);
+            }
+
+            /* Unmask all signals. */
+            if (!rc)
+            {
+                sigset_t SigMask;
+                sigemptyset(&SigMask);
+                rc = posix_spawnattr_setsigmask(&Attr, &SigMask); Assert(rc == 0);
+            }
+
+            /* File changes. */
+            posix_spawn_file_actions_t  FileActions;
+            posix_spawn_file_actions_t *pFileActions = NULL;
+            if (!rc && cRedirFds > 0)
+            {
+                rc = posix_spawn_file_actions_init(&FileActions);
+                if (!rc)
+                {
+                    pFileActions = &FileActions;
+                    for (unsigned i = 0; i < cRedirFds; i++)
+                    {
+                        int fd = paRedirFds[i];
+                        if (fd == -2)
+                            rc = posix_spawn_file_actions_addclose(&FileActions, i);
+                        else if (fd >= 0 && fd != (int)i)
+                        {
+                            rc = posix_spawn_file_actions_adddup2(&FileActions, fd, i);
+                            if (!rc)
+                            {
+                                for (unsigned j = i + 1; j < cRedirFds; j++)
+                                    if (paRedirFds[j] == fd)
+                                    {
+                                        fd = -1;
+                                        break;
+                                    }
+                                if (fd >= 0)
+                                    rc = posix_spawn_file_actions_addclose(&FileActions, fd);
+                            }
+                        }
+                        if (rc)
+                            break;
+                    }
+                }
+            }
+
+            if (!rc)
+                rc = posix_spawn(&pid, pszNativeExec, pFileActions, &Attr, (char * const *)papszArgs,
+                                 (char * const *)papszEnv);
+
+            /* cleanup */
+            int rc2 = posix_spawnattr_destroy(&Attr); Assert(rc2 == 0); NOREF(rc2);
+            if (pFileActions)
+            {
+                rc2 = posix_spawn_file_actions_destroy(pFileActions);
+                Assert(rc2 == 0);
+            }
+
+            /* return on success.*/
+            if (!rc)
+            {
+                /* For a detached process this happens in the temp process, so
+                 * it's not worth doing anything as this process must exit. */
+                if (fFlags & RTPROC_FLAGS_DETACHED)
+                    _Exit(0);
+                if (phProcess)
+                    *phProcess = pid;
+                return VINF_SUCCESS;
+            }
+        }
+        /* For a detached process this happens in the temp process, so
+         * it's not worth doing anything as this process must exit. */
+        if (fFlags & RTPROC_FLAGS_DETACHED)
+            _Exit(124);
+    }
+    else
+#endif
+    {
+#ifdef RT_OS_SOLARIS
+        int templateFd = -1;
+        if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+        {
+            templateFd = rtSolarisContractPreFork();
+            if (templateFd == -1)
+                return VERR_OPEN_FAILED;
+        }
+#endif /* RT_OS_SOLARIS */
+        pid = fork();
+        if (!pid)
+        {
+#ifdef RT_OS_SOLARIS
+            if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+                rtSolarisContractPostForkChild(templateFd);
+#endif /* RT_OS_SOLARIS */
+            if (!(fFlags & RTPROC_FLAGS_DETACHED))
+                setpgid(0, 0); /* see comment above */
+
+            /*
+             * Change group and user if requested.
+             */
+#if 1 /** @todo This needs more work, see suplib/hardening. */
+            if (pszAsUser)
+            {
+                int ret = initgroups(pszAsUser, gid);
+                if (ret)
+                {
+                    if (fFlags & RTPROC_FLAGS_DETACHED)
+                        _Exit(126);
+                    else
+                        exit(126);
+                }
+            }
+            if (gid != ~(gid_t)0)
+            {
+                if (setgid(gid))
+                {
+                    if (fFlags & RTPROC_FLAGS_DETACHED)
+                        _Exit(126);
+                    else
+                        exit(126);
+                }
+            }
+
+            if (uid != ~(uid_t)0)
+            {
+                if (setuid(uid))
+                {
+                    if (fFlags & RTPROC_FLAGS_DETACHED)
+                        _Exit(126);
+                    else
+                        exit(126);
+                }
+            }
+#endif
+
+            /*
+             * Some final profile environment tweaks, if running as user.
+             */
+            if (   (fFlags & RTPROC_FLAGS_PROFILE)
+                && pszAsUser
+                && (   (fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)
+                    || hEnv == RTENV_DEFAULT) )
+            {
+                rc = rtProcPosixAdjustProfileEnvFromChild(hEnvToUse, fFlags, hEnv);
+                papszEnv = RTEnvGetExecEnvP(hEnvToUse);
+                if (RT_FAILURE(rc) || !papszEnv)
+                {
+                    if (fFlags & RTPROC_FLAGS_DETACHED)
+                        _Exit(126);
+                    else
+                        exit(126);
+                }
+            }
+
+            /*
+             * Unset the signal mask.
+             */
+            sigset_t SigMask;
+            sigemptyset(&SigMask);
+            rc = sigprocmask(SIG_SETMASK, &SigMask, NULL);
+            Assert(rc == 0);
+
+            /*
+             * Apply changes to the standard file descriptor and stuff.
+             */
+            for (unsigned i = 0; i < cRedirFds; i++)
+            {
+                int fd = paRedirFds[i];
+                if (fd == -2)
+                    close(i);
+                else if (fd >= 0)
+                {
+                    int rc2 = dup2(fd, i);
+                    if (rc2 != (int)i)
+                    {
+                        if (fFlags & RTPROC_FLAGS_DETACHED)
+                            _Exit(125);
+                        else
+                            exit(125);
+                    }
+                    for (unsigned j = i + 1; j < cRedirFds; j++)
+                        if (paRedirFds[j] == fd)
+                        {
+                            fd = -1;
+                            break;
+                        }
+                    if (fd >= 0)
+                        close(fd);
+                }
+            }
+
+            /*
+             * Finally, execute the requested program.
+             */
+            rc = execve(pszNativeExec, (char * const *)papszArgs, (char * const *)papszEnv);
+            if (errno == ENOEXEC)
+            {
+                /* This can happen when trying to start a shell script without the magic #!/bin/sh */
+                RTAssertMsg2Weak("Cannot execute this binary format!\n");
+            }
+            else
+                RTAssertMsg2Weak("execve returns %d errno=%d (%s)\n", rc, errno, pszNativeExec);
+            RTAssertReleasePanic();
+            if (fFlags & RTPROC_FLAGS_DETACHED)
+                _Exit(127);
+            else
+                exit(127);
+        }
+#ifdef RT_OS_SOLARIS
+        if (!(fFlags & RTPROC_FLAGS_SAME_CONTRACT))
+            rtSolarisContractPostForkParent(templateFd, pid);
+#endif /* RT_OS_SOLARIS */
+        if (pid > 0)
+        {
+            /* For a detached process this happens in the temp process, so
+             * it's not worth doing anything as this process must exit. */
+            if (fFlags & RTPROC_FLAGS_DETACHED)
+                _Exit(0);
+            if (phProcess)
+                *phProcess = pid;
+            return VINF_SUCCESS;
+        }
+        /* For a detached process this happens in the temp process, so
+         * it's not worth doing anything as this process must exit. */
+        if (fFlags & RTPROC_FLAGS_DETACHED)
+            _Exit(124);
+        return RTErrConvertFromErrno(errno);
+    }
+
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTR3DECL(int)   RTProcDaemonizeUsingFork(bool fNoChDir, bool fNoClose, const char *pszPidfile)
+{
+    /*
+     * Fork the child process in a new session and quit the parent.
+     *
+     * - fork once and create a new session (setsid). This will detach us
+     *   from the controlling tty meaning that we won't receive the SIGHUP
+     *   (or any other signal) sent to that session.
+     * - The SIGHUP signal is ignored because the session/parent may throw
+     *   us one before we get to the setsid.
+     * - When the parent exit(0) we will become an orphan and re-parented to
+     *   the init process.
+     * - Because of the sometimes unexpected semantics of assigning the
+     *   controlling tty automagically when a session leader first opens a tty,
+     *   we will fork() once more to get rid of the session leadership role.
+     */
+
+    /* We start off by opening the pidfile, so that we can fail straight away
+     * if it already exists. */
+    int fdPidfile = -1;
+    if (pszPidfile != NULL)
+    {
+        /* @note the exclusive create is not guaranteed on all file
+         * systems (e.g. NFSv2) */
+        if ((fdPidfile = open(pszPidfile, O_RDWR | O_CREAT | O_EXCL, 0644)) == -1)
+            return RTErrConvertFromErrno(errno);
+    }
+
+    /* Ignore SIGHUP straight away. */
+    struct sigaction OldSigAct;
+    struct sigaction SigAct;
+    memset(&SigAct, 0, sizeof(SigAct));
+    SigAct.sa_handler = SIG_IGN;
+    int rcSigAct = sigaction(SIGHUP, &SigAct, &OldSigAct);
+
+    /* First fork, to become independent process. */
+    pid_t pid = fork();
+    if (pid == -1)
+    {
+        if (fdPidfile != -1)
+            close(fdPidfile);
+        return RTErrConvertFromErrno(errno);
+    }
+    if (pid != 0)
+    {
+        /* Parent exits, no longer necessary. The child gets reparented
+         * to the init process. */
+        exit(0);
+    }
+
+    /* Create new session, fix up the standard file descriptors and the
+     * current working directory. */
+    /** @todo r=klaus the webservice uses this function and assumes that the
+     * contract id of the daemon is the same as that of the original process.
+     * Whenever this code is changed this must still remain possible. */
+    pid_t newpgid = setsid();
+    int SavedErrno = errno;
+    if (rcSigAct != -1)
+        sigaction(SIGHUP, &OldSigAct, NULL);
+    if (newpgid == -1)
+    {
+        if (fdPidfile != -1)
+            close(fdPidfile);
+        return RTErrConvertFromErrno(SavedErrno);
+    }
+
+    if (!fNoClose)
+    {
+        /* Open stdin(0), stdout(1) and stderr(2) as /dev/null. */
+        int fd = open("/dev/null", O_RDWR);
+        if (fd == -1) /* paranoia */
+        {
+            close(STDIN_FILENO);
+            close(STDOUT_FILENO);
+            close(STDERR_FILENO);
+            fd = open("/dev/null", O_RDWR);
+        }
+        if (fd != -1)
+        {
+            dup2(fd, STDIN_FILENO);
+            dup2(fd, STDOUT_FILENO);
+            dup2(fd, STDERR_FILENO);
+            if (fd > 2)
+                close(fd);
+        }
+    }
+
+    if (!fNoChDir)
+    {
+        int rcIgnored = chdir("/");
+        NOREF(rcIgnored);
+    }
+
+    /* Second fork to lose session leader status. */
+    pid = fork();
+    if (pid == -1)
+    {
+        if (fdPidfile != -1)
+            close(fdPidfile);
+        return RTErrConvertFromErrno(errno);
+    }
+
+    if (pid != 0)
+    {
+        /* Write the pid file, this is done in the parent, before exiting. */
+        if (fdPidfile != -1)
+        {
+            char szBuf[256];
+            size_t cbPid = RTStrPrintf(szBuf, sizeof(szBuf), "%d\n", pid);
+            ssize_t cbIgnored = write(fdPidfile, szBuf, cbPid); NOREF(cbIgnored);
+            close(fdPidfile);
+        }
+        exit(0);
+    }
+
+    if (fdPidfile != -1)
+        close(fdPidfile);
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/process-posix.cpp b/src/VBox/Runtime/r3/posix/process-posix.cpp
new file mode 100644
index 00000000..b0074f1c
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/process-posix.cpp
@@ -0,0 +1,279 @@
+/* $Id: process-posix.cpp $ */
+/** @file
+ * IPRT - Process, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <pwd.h>
+
+#include <iprt/process.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/pipe.h>
+#include <iprt/socket.h>
+#include <iprt/string.h>
+#include <iprt/mem.h>
+#include "internal/process.h"
+
+
+RTR3DECL(int)   RTProcWait(RTPROCESS Process, unsigned fFlags, PRTPROCSTATUS pProcStatus)
+{
+    int rc;
+    do rc = RTProcWaitNoResume(Process, fFlags, pProcStatus);
+    while (rc == VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTR3DECL(int)   RTProcWaitNoResume(RTPROCESS Process, unsigned fFlags, PRTPROCSTATUS pProcStatus)
+{
+    /*
+     * Validate input.
+     */
+    if (Process <= 0)
+    {
+        AssertMsgFailed(("Invalid Process=%d\n", Process));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (fFlags & ~(RTPROCWAIT_FLAGS_NOBLOCK | RTPROCWAIT_FLAGS_BLOCK))
+    {
+        AssertMsgFailed(("Invalid flags %#x\n", fFlags));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Perform the wait.
+     */
+    int iStatus = 0;
+    int rc = waitpid(Process, &iStatus, fFlags & RTPROCWAIT_FLAGS_NOBLOCK ? WNOHANG : 0);
+    if (rc > 0)
+    {
+        /*
+         * Fill in the status structure.
+         */
+        if (pProcStatus)
+        {
+            if (WIFEXITED(iStatus))
+            {
+                pProcStatus->enmReason = RTPROCEXITREASON_NORMAL;
+                pProcStatus->iStatus = WEXITSTATUS(iStatus);
+            }
+            else if (WIFSIGNALED(iStatus))
+            {
+                pProcStatus->enmReason = RTPROCEXITREASON_SIGNAL;
+                pProcStatus->iStatus = WTERMSIG(iStatus);
+            }
+            else
+            {
+                Assert(!WIFSTOPPED(iStatus));
+                pProcStatus->enmReason = RTPROCEXITREASON_ABEND;
+                pProcStatus->iStatus = iStatus;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Child running?
+     */
+    if (!rc)
+    {
+        Assert(fFlags & RTPROCWAIT_FLAGS_NOBLOCK);
+        return VERR_PROCESS_RUNNING;
+    }
+
+    /*
+     * Figure out which error to return.
+     */
+    int iErr = errno;
+    if (iErr == ECHILD)
+        return VERR_PROCESS_NOT_FOUND;
+    return RTErrConvertFromErrno(iErr);
+}
+
+
+RTR3DECL(int) RTProcTerminate(RTPROCESS Process)
+{
+    if (Process == NIL_RTPROCESS)
+        return VINF_SUCCESS;
+
+    if (!kill(Process, SIGKILL))
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(uint64_t) RTProcGetAffinityMask(void)
+{
+    /// @todo
+    return 1;
+}
+
+
+RTR3DECL(int) RTProcQueryParent(RTPROCESS hProcess, PRTPROCESS phParent)
+{
+    if (hProcess == RTProcSelf())
+    {
+        *phParent = getppid();
+        return VINF_SUCCESS;
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTR3DECL(int) RTProcQueryUsername(RTPROCESS hProcess, char *pszUser, size_t cbUser, size_t *pcbUser)
+{
+    AssertReturn(   (pszUser && cbUser > 0)
+                 || (!pszUser && !cbUser), VERR_INVALID_PARAMETER);
+    AssertReturn(pcbUser || pszUser, VERR_INVALID_PARAMETER);
+
+    int rc;
+    if (   hProcess == NIL_RTPROCESS
+        || hProcess == RTProcSelf())
+    {
+        /*
+         * Figure a good buffer estimate.
+         */
+        int32_t cbPwdMax = sysconf(_SC_GETPW_R_SIZE_MAX);
+        if (cbPwdMax <= _1K)
+            cbPwdMax = _1K;
+        else
+            AssertStmt(cbPwdMax <= 32*_1M, cbPwdMax = 32*_1M);
+        char *pchBuf = (char *)RTMemTmpAllocZ(cbPwdMax);
+        if (pchBuf)
+        {
+            /*
+             * Get the password file entry.
+             */
+            struct passwd  Pwd;
+            struct passwd *pPwd = NULL;
+            rc = getpwuid_r(geteuid(), &Pwd, pchBuf, cbPwdMax, &pPwd);
+            if (!rc)
+            {
+                /*
+                 * Convert the name to UTF-8, assuming that we're getting it in the local codeset.
+                 */
+                /** @todo This isn't exactly optimal... the current codeset/page conversion
+                 *        stuff never was.  Should optimize that for UTF-8 and ASCII one day.
+                 *        And also optimize for avoiding heap. */
+                char *pszTmp = NULL;
+                rc = RTStrCurrentCPToUtf8(&pszTmp, pPwd->pw_name);
+                if (RT_SUCCESS(rc))
+                {
+                    size_t cbTmp = strlen(pszTmp) + 1;
+                    if (pcbUser)
+                        *pcbUser = cbTmp;
+                    if (cbTmp <= cbUser)
+                    {
+                        memcpy(pszUser, pszTmp, cbTmp);
+                        rc = VINF_SUCCESS;
+                    }
+                    else
+                        rc = VERR_BUFFER_OVERFLOW;
+                    RTStrFree(pszTmp);
+                }
+            }
+            else
+                rc = RTErrConvertFromErrno(rc);
+            RTMemFree(pchBuf);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
+
+RTR3DECL(int) RTProcQueryUsernameA(RTPROCESS hProcess, char **ppszUser)
+{
+    AssertPtrReturn(ppszUser, VERR_INVALID_POINTER);
+
+    int rc;
+    if (   hProcess == NIL_RTPROCESS
+        || hProcess == RTProcSelf())
+    {
+        /*
+         * Figure a good buffer estimate.
+         */
+        int32_t cbPwdMax = sysconf(_SC_GETPW_R_SIZE_MAX);
+        if (cbPwdMax <= _1K)
+            cbPwdMax = _1K;
+        else
+            AssertStmt(cbPwdMax <= 32*_1M, cbPwdMax = 32*_1M);
+        char *pchBuf = (char *)RTMemTmpAllocZ(cbPwdMax);
+        if (pchBuf)
+        {
+            /*
+             * Get the password file entry.
+             */
+            struct passwd  Pwd;
+            struct passwd *pPwd = NULL;
+            rc = getpwuid_r(geteuid(), &Pwd, pchBuf, cbPwdMax, &pPwd);
+            if (!rc)
+            {
+                /*
+                 * Convert the name to UTF-8, assuming that we're getting it in the local codeset.
+                 */
+                rc = RTStrCurrentCPToUtf8(ppszUser, pPwd->pw_name);
+            }
+            else
+                rc = RTErrConvertFromErrno(rc);
+            RTMemFree(pchBuf);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/rand-posix.cpp b/src/VBox/Runtime/r3/posix/rand-posix.cpp
new file mode 100644
index 00000000..191e3db8
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/rand-posix.cpp
@@ -0,0 +1,148 @@
+/* $Id: rand-posix.cpp $ */
+/** @file
+ * IPRT - Random Numbers and Byte Streams, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <fcntl.h>
+#ifdef _MSC_VER
+# include <io.h>
+# include <stdio.h>
+#else
+# include <unistd.h>
+# include <sys/time.h>
+#endif
+
+#include <iprt/rand.h>
+#include <iprt/mem.h>
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include "internal/rand.h"
+#include "internal/magics.h"
+
+
+
+/** @copydoc RTRANDINT::pfnGetBytes */
+static DECLCALLBACK(void) rtRandAdvPosixGetBytes(PRTRANDINT pThis, uint8_t *pb, size_t cb)
+{
+    ssize_t cbRead = read(pThis->u.File.hFile, pb, cb);
+    if ((size_t)cbRead != cb)
+    {
+        /* S10 has been observed returning 1040 bytes at the time from /dev/urandom.
+           Which means we need to do than 256 rounds to reach 668171 bytes if
+           that's what demanded by the caller (like tstRTMemWipe.cpp). */
+        ssize_t cTries = RT_MAX(256, cb / 64);
+        do
+        {
+            if (cbRead > 0)
+            {
+                cb -= cbRead;
+                pb += cbRead;
+            }
+            cbRead = read(pThis->u.File.hFile, pb, cb);
+        } while (   (size_t)cbRead != cb
+                 && cTries-- > 0);
+        AssertReleaseMsg((size_t)cbRead == cb, ("%zu != %zu, cTries=%zd errno=%d\n", cbRead, cb, cTries, errno));
+    }
+}
+
+
+/** @copydoc RTRANDINT::pfnDestroy */
+static DECLCALLBACK(int) rtRandAdvPosixDestroy(PRTRANDINT pThis)
+{
+    pThis->u32Magic = ~RTRANDINT_MAGIC;
+    int fd = pThis->u.File.hFile;
+    pThis->u.File.hFile = -1;
+    RTMemFree(pThis);
+    close(fd);
+    return VINF_SUCCESS;
+}
+
+
+static int rtRandAdvPosixCreateSystem(PRTRAND phRand, const char *pszDev) RT_NO_THROW_DEF
+{
+    /*
+     * Try open it first and then setup the handle structure.
+     */
+    int fd = open(pszDev, O_RDONLY);
+    if (fd < 0)
+        return RTErrConvertFromErrno(errno);
+    int rc;
+    if (fcntl(fd, F_SETFD, FD_CLOEXEC) != -1)
+    {
+        PRTRANDINT pThis = (PRTRANDINT)RTMemAlloc(sizeof(*pThis));
+        if (pThis)
+        {
+            pThis->u32Magic     = RTRANDINT_MAGIC;
+            pThis->pfnGetBytes  = rtRandAdvPosixGetBytes;
+            pThis->pfnGetU32    = rtRandAdvSynthesizeU32FromBytes;
+            pThis->pfnGetU64    = rtRandAdvSynthesizeU64FromBytes;
+            pThis->pfnSeed      = rtRandAdvStubSeed;
+            pThis->pfnSaveState = rtRandAdvStubSaveState;
+            pThis->pfnRestoreState = rtRandAdvStubRestoreState;
+            pThis->pfnDestroy   = rtRandAdvPosixDestroy;
+            pThis->u.File.hFile = fd;
+
+            *phRand = pThis;
+            return VINF_SUCCESS;
+        }
+
+        /* bail out */
+        rc = VERR_NO_MEMORY;
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+    close(fd);
+    return rc;
+}
+
+
+RTDECL(int) RTRandAdvCreateSystemFaster(PRTRAND phRand) RT_NO_THROW_DEF
+{
+    return rtRandAdvPosixCreateSystem(phRand, "/dev/urandom");
+}
+
+
+RTDECL(int) RTRandAdvCreateSystemTruer(PRTRAND phRand) RT_NO_THROW_DEF
+{
+    return rtRandAdvPosixCreateSystem(phRand, "/dev/random");
+}
+
diff --git a/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-heap-posix.cpp b/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-heap-posix.cpp
new file mode 100644
index 00000000..2bb60178
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-heap-posix.cpp
@@ -0,0 +1,797 @@
+/* $Id: rtmempage-exec-mmap-heap-posix.cpp $ */
+/** @file
+ * IPRT - RTMemPage*, POSIX with heap.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/mem.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/avl.h>
+#include <iprt/critsect.h>
+#include <iprt/errcore.h>
+#include <iprt/once.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include "internal/mem.h"
+#include "../alloc-ef.h"
+
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/mman.h>
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Threshold at which to we switch to simply calling mmap. */
+#define RTMEMPAGEPOSIX_MMAP_THRESHOLD   _128K
+/** The size of a heap block (power of two) - in bytes. */
+#define RTMEMPAGEPOSIX_BLOCK_SIZE       _2M
+AssertCompile(RTMEMPAGEPOSIX_BLOCK_SIZE == (RTMEMPAGEPOSIX_BLOCK_SIZE / PAGE_SIZE) * PAGE_SIZE);
+/** The number of pages per heap block. */
+#define RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT (RTMEMPAGEPOSIX_BLOCK_SIZE / PAGE_SIZE)
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Pointer to a page heap block. */
+typedef struct RTHEAPPAGEBLOCK *PRTHEAPPAGEBLOCK;
+
+/**
+ * A simple page heap.
+ */
+typedef struct RTHEAPPAGE
+{
+    /** Magic number (RTHEAPPAGE_MAGIC). */
+    uint32_t            u32Magic;
+    /** The number of pages in the heap (in BlockTree). */
+    uint32_t            cHeapPages;
+    /** The number of currently free pages. */
+    uint32_t            cFreePages;
+    /** Number of successful calls. */
+    uint32_t            cAllocCalls;
+    /** Number of successful free calls. */
+    uint32_t            cFreeCalls;
+    /** The free call number at which we last tried to minimize the heap. */
+    uint32_t            uLastMinimizeCall;
+    /** Tree of heap blocks. */
+    AVLRPVTREE          BlockTree;
+    /** Allocation hint no 1 (last freed). */
+    PRTHEAPPAGEBLOCK    pHint1;
+    /** Allocation hint no 2 (last alloc). */
+    PRTHEAPPAGEBLOCK    pHint2;
+    /** Critical section protecting the heap. */
+    RTCRITSECT          CritSect;
+    /** Set if the memory must allocated with execute access. */
+    bool                fExec;
+} RTHEAPPAGE;
+#define RTHEAPPAGE_MAGIC     UINT32_C(0xfeedface)
+/** Pointer to a page heap. */
+typedef RTHEAPPAGE *PRTHEAPPAGE;
+
+
+/**
+ * Describes a page heap block.
+ */
+typedef struct RTHEAPPAGEBLOCK
+{
+    /** The AVL tree node core (void pointer range). */
+    AVLRPVNODECORE      Core;
+    /** Allocation bitmap.  Set bits marks allocated pages. */
+    uint32_t            bmAlloc[RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT / 32];
+    /** Allocation boundrary bitmap.  Set bits marks the start of
+     *  allocations. */
+    uint32_t            bmFirst[RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT / 32];
+    /** The number of free pages. */
+    uint32_t            cFreePages;
+    /** Pointer back to the heap. */
+    PRTHEAPPAGE         pHeap;
+} RTHEAPPAGEBLOCK;
+
+
+/**
+ * Argument package for rtHeapPageAllocCallback.
+ */
+typedef struct RTHEAPPAGEALLOCARGS
+{
+    /** The number of pages to allocate. */
+    size_t          cPages;
+    /** Non-null on success.  */
+    void           *pvAlloc;
+    /** RTMEMPAGEALLOC_F_XXX. */
+    uint32_t        fFlags;
+} RTHEAPPAGEALLOCARGS;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Initialize once structure. */
+static RTONCE       g_MemPagePosixInitOnce = RTONCE_INITIALIZER;
+/** The page heap. */
+static RTHEAPPAGE   g_MemPagePosixHeap;
+/** The exec page heap. */
+static RTHEAPPAGE   g_MemExecPosixHeap;
+
+
+#ifdef RT_OS_OS2
+/*
+ * A quick mmap/munmap mockup for avoid duplicating lots of good code.
+ */
+# define INCL_BASE
+# include <os2.h>
+# undef  MAP_PRIVATE
+# define MAP_PRIVATE    0
+# undef  MAP_ANONYMOUS
+# define MAP_ANONYMOUS  0
+# undef  MAP_FAILED
+# define MAP_FAILED  (void *)-1
+# undef mmap
+# define mmap   iprt_mmap
+# undef munmap
+# define munmap iprt_munmap
+
+static void *mmap(void *pvWhere, size_t cb, int fProt, int fFlags, int fd, off_t off)
+{
+    NOREF(pvWhere); NOREF(fd); NOREF(off);
+    void   *pv    = NULL;
+    ULONG  fAlloc = OBJ_ANY | PAG_COMMIT;
+    if (fProt & PROT_EXEC)
+        fAlloc |= PAG_EXECUTE;
+    if (fProt & PROT_READ)
+        fAlloc |= PAG_READ;
+    if (fProt & PROT_WRITE)
+        fAlloc |= PAG_WRITE;
+    APIRET rc = DosAllocMem(&pv, cb, fAlloc);
+    if (rc == NO_ERROR)
+        return pv;
+    errno = ENOMEM;
+    return MAP_FAILED;
+}
+
+static int munmap(void *pv, size_t cb)
+{
+    APIRET rc = DosFreeMem(pv);
+    if (rc == NO_ERROR)
+        return 0;
+    errno = EINVAL;
+    return -1;
+}
+
+#endif
+
+/**
+ * Initializes the heap.
+ *
+ * @returns IPRT status code.
+ * @param   pHeap           The page heap to initialize.
+ * @param   fExec           Whether the heap memory should be marked as
+ *                          executable or not.
+ */
+int RTHeapPageInit(PRTHEAPPAGE pHeap, bool fExec)
+{
+    int rc = RTCritSectInitEx(&pHeap->CritSect,
+                              RTCRITSECT_FLAGS_NO_LOCK_VAL | RTCRITSECT_FLAGS_NO_NESTING | RTCRITSECT_FLAGS_BOOTSTRAP_HACK,
+                              NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        pHeap->cHeapPages           = 0;
+        pHeap->cFreePages           = 0;
+        pHeap->cAllocCalls          = 0;
+        pHeap->cFreeCalls           = 0;
+        pHeap->uLastMinimizeCall    = 0;
+        pHeap->BlockTree            = NULL;
+        pHeap->fExec                = fExec;
+        pHeap->u32Magic             = RTHEAPPAGE_MAGIC;
+    }
+    return rc;
+}
+
+
+/**
+ * Deletes the heap and all the memory it tracks.
+ *
+ * @returns IPRT status code.
+ * @param   pHeap           The page heap to delete.
+ */
+int RTHeapPageDelete(PRTHEAPPAGE pHeap)
+{
+    NOREF(pHeap);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+/**
+ * Applies flags to an allocation.
+ *
+ * @param   pv              The allocation.
+ * @param   cb              The size of the allocation (page aligned).
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ */
+DECLINLINE(void) rtMemPagePosixApplyFlags(void *pv, size_t cb, uint32_t fFlags)
+{
+#ifndef RT_OS_OS2
+    if (fFlags & RTMEMPAGEALLOC_F_ADVISE_LOCKED)
+    {
+        int rc = mlock(pv, cb);
+# ifndef RT_OS_SOLARIS /* mlock(3C) on Solaris requires the priv_lock_memory privilege */
+        AssertMsg(rc == 0, ("mlock %p LB %#zx -> %d errno=%d\n", pv, cb, rc, errno));
+# endif
+        NOREF(rc);
+    }
+
+# ifdef MADV_DONTDUMP
+    if (fFlags & RTMEMPAGEALLOC_F_ADVISE_NO_DUMP)
+    {
+        int rc = madvise(pv, cb, MADV_DONTDUMP);
+        AssertMsg(rc == 0, ("madvice %p LB %#zx MADV_DONTDUMP -> %d errno=%d\n", pv, cb, rc, errno));
+        NOREF(rc);
+    }
+# endif
+#endif
+
+    if (fFlags & RTMEMPAGEALLOC_F_ZERO)
+        RT_BZERO(pv, cb);
+}
+
+
+/**
+ * Avoids some gotos in rtHeapPageAllocFromBlock.
+ *
+ * @returns VINF_SUCCESS.
+ * @param   pBlock          The block.
+ * @param   iPage           The page to start allocating at.
+ * @param   cPages          The number of pages.
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ * @param   ppv             Where to return the allocation address.
+ */
+DECLINLINE(int) rtHeapPageAllocFromBlockSuccess(PRTHEAPPAGEBLOCK pBlock, uint32_t iPage, size_t cPages, uint32_t fFlags, void **ppv)
+{
+    PRTHEAPPAGE pHeap = pBlock->pHeap;
+
+    ASMBitSet(&pBlock->bmFirst[0], iPage);
+    pBlock->cFreePages -= cPages;
+    pHeap->cFreePages  -= cPages;
+    if (!pHeap->pHint2 || pHeap->pHint2->cFreePages < pBlock->cFreePages)
+        pHeap->pHint2 = pBlock;
+    pHeap->cAllocCalls++;
+
+    void *pv = (uint8_t *)pBlock->Core.Key + (iPage << PAGE_SHIFT);
+    *ppv = pv;
+
+    if (fFlags)
+        rtMemPagePosixApplyFlags(pv, cPages << PAGE_SHIFT, fFlags);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks if a page range is free in the specified block.
+ *
+ * @returns @c true if the range is free, @c false if not.
+ * @param   pBlock          The block.
+ * @param   iFirst          The first page to check.
+ * @param   cPages          The number of pages to check.
+ */
+DECLINLINE(bool) rtHeapPageIsPageRangeFree(PRTHEAPPAGEBLOCK pBlock, uint32_t iFirst, uint32_t cPages)
+{
+    uint32_t i = iFirst + cPages;
+    while (i-- > iFirst)
+    {
+        if (ASMBitTest(&pBlock->bmAlloc[0], i))
+            return false;
+        Assert(!ASMBitTest(&pBlock->bmFirst[0], i));
+    }
+    return true;
+}
+
+
+/**
+ * Tries to allocate a chunk of pages from a heap block.
+ *
+ * @retval  VINF_SUCCESS on success.
+ * @retval  VERR_NO_MEMORY if the allocation failed.
+ * @param   pBlock          The block to allocate from.
+ * @param   cPages          The size of the allocation.
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ * @param   ppv             Where to return the allocation address on success.
+ */
+DECLINLINE(int) rtHeapPageAllocFromBlock(PRTHEAPPAGEBLOCK pBlock, size_t cPages, uint32_t fFlags, void **ppv)
+{
+    if (pBlock->cFreePages >= cPages)
+    {
+        int iPage = ASMBitFirstClear(&pBlock->bmAlloc[0], RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT);
+        Assert(iPage >= 0);
+
+        /* special case: single page. */
+        if (cPages == 1)
+        {
+            ASMBitSet(&pBlock->bmAlloc[0], iPage);
+            return rtHeapPageAllocFromBlockSuccess(pBlock, iPage, cPages, fFlags, ppv);
+        }
+
+        while (   iPage >= 0
+               && (unsigned)iPage <= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT - cPages)
+        {
+            if (rtHeapPageIsPageRangeFree(pBlock, iPage + 1, cPages - 1))
+            {
+                ASMBitSetRange(&pBlock->bmAlloc[0], iPage, iPage + cPages);
+                return rtHeapPageAllocFromBlockSuccess(pBlock, iPage, cPages, fFlags, ppv);
+            }
+
+            /* next */
+            iPage = ASMBitNextSet(&pBlock->bmAlloc[0], RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT, iPage);
+            if (iPage < 0 || iPage >= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT - 1)
+                break;
+            iPage = ASMBitNextClear(&pBlock->bmAlloc[0], RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT, iPage);
+        }
+    }
+
+    return VERR_NO_MEMORY;
+}
+
+
+/**
+ * RTAvlrPVDoWithAll callback.
+ *
+ * @returns 0 to continue the enum, non-zero to quit it.
+ * @param   pNode           The node.
+ * @param   pvUser          The user argument.
+ */
+static DECLCALLBACK(int) rtHeapPageAllocCallback(PAVLRPVNODECORE pNode, void *pvUser)
+{
+    PRTHEAPPAGEBLOCK        pBlock = RT_FROM_MEMBER(pNode,  RTHEAPPAGEBLOCK, Core);
+    RTHEAPPAGEALLOCARGS    *pArgs  = (RTHEAPPAGEALLOCARGS *)pvUser;
+    int rc = rtHeapPageAllocFromBlock(pBlock, pArgs->cPages, pArgs->fFlags, &pArgs->pvAlloc);
+    return RT_SUCCESS(rc) ? 1 : 0;
+}
+
+
+/**
+ * Worker for RTHeapPageAlloc.
+ *
+ * @returns IPRT status code
+ * @param   pHeap           The heap - locked.
+ * @param   cPages          The page count.
+ * @param   pszTag          The tag.
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ * @param   ppv             Where to return the address of the allocation
+ *                          on success.
+ */
+static int rtHeapPageAllocLocked(PRTHEAPPAGE pHeap, size_t cPages, const char *pszTag, uint32_t fFlags, void **ppv)
+{
+    int rc;
+    NOREF(pszTag);
+
+    /*
+     * Use the hints first.
+     */
+    if (pHeap->pHint1)
+    {
+        rc = rtHeapPageAllocFromBlock(pHeap->pHint1, cPages, fFlags, ppv);
+        if (rc != VERR_NO_MEMORY)
+            return rc;
+    }
+    if (pHeap->pHint2)
+    {
+        rc = rtHeapPageAllocFromBlock(pHeap->pHint2, cPages, fFlags, ppv);
+        if (rc != VERR_NO_MEMORY)
+            return rc;
+    }
+
+    /*
+     * Search the heap for a block with enough free space.
+     *
+     * N.B. This search algorithm is not optimal at all. What (hopefully) saves
+     *      it are the two hints above.
+     */
+    if (pHeap->cFreePages >= cPages)
+    {
+        RTHEAPPAGEALLOCARGS Args;
+        Args.cPages  = cPages;
+        Args.pvAlloc = NULL;
+        Args.fFlags  = fFlags;
+        RTAvlrPVDoWithAll(&pHeap->BlockTree, true /*fFromLeft*/, rtHeapPageAllocCallback, &Args);
+        if (Args.pvAlloc)
+        {
+            *ppv = Args.pvAlloc;
+            return VINF_SUCCESS;
+        }
+    }
+
+    /*
+     * Didn't find anytyhing, so expand the heap with a new block.
+     */
+    RTCritSectLeave(&pHeap->CritSect);
+    void *pvPages;
+    pvPages = mmap(NULL, RTMEMPAGEPOSIX_BLOCK_SIZE,
+                   PROT_READ | PROT_WRITE | (pHeap->fExec ? PROT_EXEC : 0),
+                   MAP_PRIVATE | MAP_ANONYMOUS,
+                   -1, 0);
+    if (pvPages == MAP_FAILED)
+    {
+        RTCritSectEnter(&pHeap->CritSect);
+        return RTErrConvertFromErrno(errno);
+
+    }
+    /** @todo Eliminate this rtMemBaseAlloc dependency! */
+    PRTHEAPPAGEBLOCK pBlock;
+#ifdef RTALLOC_REPLACE_MALLOC
+    if (g_pfnOrgMalloc)
+        pBlock = (PRTHEAPPAGEBLOCK)g_pfnOrgMalloc(sizeof(*pBlock));
+    else
+#endif
+        pBlock = (PRTHEAPPAGEBLOCK)rtMemBaseAlloc(sizeof(*pBlock));
+    if (!pBlock)
+    {
+        munmap(pvPages, RTMEMPAGEPOSIX_BLOCK_SIZE);
+        RTCritSectEnter(&pHeap->CritSect);
+        return VERR_NO_MEMORY;
+    }
+
+    RT_ZERO(*pBlock);
+    pBlock->Core.Key        = pvPages;
+    pBlock->Core.KeyLast    = (uint8_t *)pvPages + RTMEMPAGEPOSIX_BLOCK_SIZE - 1;
+    pBlock->cFreePages      = RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+    pBlock->pHeap           = pHeap;
+
+    RTCritSectEnter(&pHeap->CritSect);
+
+    bool fRc = RTAvlrPVInsert(&pHeap->BlockTree, &pBlock->Core); Assert(fRc); NOREF(fRc);
+    pHeap->cFreePages      +=  RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+    pHeap->cHeapPages      +=  RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+
+    /*
+     * Grab memory from the new block (cannot fail).
+     */
+    rc = rtHeapPageAllocFromBlock(pBlock, cPages, fFlags, ppv);
+    Assert(rc == VINF_SUCCESS);
+
+    return rc;
+}
+
+
+/**
+ * Allocates one or more pages off the heap.
+ *
+ * @returns IPRT status code.
+ * @param   pHeap           The page heap.
+ * @param   cPages          The number of pages to allocate.
+ * @param   pszTag          The allocation tag.
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ * @param   ppv             Where to return the pointer to the pages.
+ */
+int RTHeapPageAlloc(PRTHEAPPAGE pHeap, size_t cPages, const char *pszTag, uint32_t fFlags, void **ppv)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtr(ppv);
+    *ppv = NULL;
+    AssertPtrReturn(pHeap, VERR_INVALID_HANDLE);
+    AssertReturn(pHeap->u32Magic == RTHEAPPAGE_MAGIC, VERR_INVALID_HANDLE);
+    AssertMsgReturn(cPages < RTMEMPAGEPOSIX_BLOCK_SIZE, ("%#zx\n", cPages), VERR_OUT_OF_RANGE);
+
+    /*
+     * Grab the lock and call a worker with many returns.
+     */
+    int rc = RTCritSectEnter(&pHeap->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtHeapPageAllocLocked(pHeap, cPages, pszTag, fFlags, ppv);
+        RTCritSectLeave(&pHeap->CritSect);
+    }
+
+    return rc;
+}
+
+
+/**
+ * RTAvlrPVDoWithAll callback.
+ *
+ * @returns 0 to continue the enum, non-zero to quit it.
+ * @param   pNode           The node.
+ * @param   pvUser          Pointer to a block pointer variable. For returning
+ *                          the address of the block to be freed.
+ */
+static DECLCALLBACK(int) rtHeapPageFindUnusedBlockCallback(PAVLRPVNODECORE pNode, void *pvUser)
+{
+    PRTHEAPPAGEBLOCK pBlock = RT_FROM_MEMBER(pNode, RTHEAPPAGEBLOCK, Core);
+    if (pBlock->cFreePages == RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT)
+    {
+        *(PRTHEAPPAGEBLOCK *)pvUser = pBlock;
+        return 1;
+    }
+    return 0;
+}
+
+
+/**
+ * Allocates one or more pages off the heap.
+ *
+ * @returns IPRT status code.
+ * @param   pHeap           The page heap.
+ * @param   pv              Pointer to what RTHeapPageAlloc returned.
+ * @param   cPages          The number of pages that was allocated.
+ */
+int RTHeapPageFree(PRTHEAPPAGE pHeap, void *pv, size_t cPages)
+{
+    /*
+     * Validate input.
+     */
+    if (!pv)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pHeap, VERR_INVALID_HANDLE);
+    AssertReturn(pHeap->u32Magic == RTHEAPPAGE_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Grab the lock and look up the page.
+     */
+    int rc = RTCritSectEnter(&pHeap->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        PRTHEAPPAGEBLOCK pBlock = (PRTHEAPPAGEBLOCK)RTAvlrPVRangeGet(&pHeap->BlockTree, pv);
+        if (pBlock)
+        {
+            /*
+             * Validate the specified address range.
+             */
+            uint32_t const iPage = (uint32_t)(((uintptr_t)pv - (uintptr_t)pBlock->Core.Key) >> PAGE_SHIFT);
+            /* Check the range is within the block. */
+            bool fOk = iPage + cPages <= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+            /* Check that it's the start of an allocation. */
+            fOk = fOk && ASMBitTest(&pBlock->bmFirst[0], iPage);
+            /* Check that the range ends at an allocation boundrary. */
+            fOk = fOk && (   iPage + cPages == RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT
+                          || ASMBitTest(&pBlock->bmFirst[0], iPage + cPages)
+                          || !ASMBitTest(&pBlock->bmAlloc[0], iPage + cPages));
+            /* Check the other pages. */
+            uint32_t const iLastPage = iPage + cPages - 1;
+            for (uint32_t i = iPage + 1; i < iLastPage && fOk; i++)
+                fOk = ASMBitTest(&pBlock->bmAlloc[0], i)
+                   && !ASMBitTest(&pBlock->bmFirst[0], i);
+            if (fOk)
+            {
+                /*
+                 * Free the memory.
+                 */
+                ASMBitClearRange(&pBlock->bmAlloc[0], iPage, iPage + cPages);
+                ASMBitClear(&pBlock->bmFirst[0], iPage);
+                pBlock->cFreePages += cPages;
+                pHeap->cFreePages  += cPages;
+                pHeap->cFreeCalls++;
+                if (!pHeap->pHint1 || pHeap->pHint1->cFreePages < pBlock->cFreePages)
+                    pHeap->pHint1 = pBlock;
+
+                /** @todo Add bitmaps for tracking madvice and mlock so we can undo those. */
+
+                /*
+                 * Shrink the heap. Not very efficient because of the AVL tree.
+                 */
+                if (   pHeap->cFreePages >= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT * 3
+                    && pHeap->cFreePages >= pHeap->cHeapPages / 2 /* 50% free */
+                    && pHeap->cFreeCalls - pHeap->uLastMinimizeCall > RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT
+                   )
+                {
+                    uint32_t cFreePageTarget = pHeap->cHeapPages / 4; /* 25% free */
+                    while (pHeap->cFreePages > cFreePageTarget)
+                    {
+                        pHeap->uLastMinimizeCall = pHeap->cFreeCalls;
+
+                        pBlock = NULL;
+                        RTAvlrPVDoWithAll(&pHeap->BlockTree, false /*fFromLeft*/,
+                                          rtHeapPageFindUnusedBlockCallback, &pBlock);
+                        if (!pBlock)
+                            break;
+
+                        void *pv2 = RTAvlrPVRemove(&pHeap->BlockTree, pBlock->Core.Key); Assert(pv2); NOREF(pv2);
+                        pHeap->cHeapPages -= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+                        pHeap->cFreePages -= RTMEMPAGEPOSIX_BLOCK_PAGE_COUNT;
+                        pHeap->pHint1      = NULL;
+                        pHeap->pHint2      = NULL;
+                        RTCritSectLeave(&pHeap->CritSect);
+
+                        munmap(pBlock->Core.Key, RTMEMPAGEPOSIX_BLOCK_SIZE);
+                        pBlock->Core.Key = pBlock->Core.KeyLast = NULL;
+                        pBlock->cFreePages = 0;
+#ifdef RTALLOC_REPLACE_MALLOC
+                        if (g_pfnOrgFree)
+                            g_pfnOrgFree(pBlock);
+                        else
+#endif
+                            rtMemBaseFree(pBlock);
+
+                        RTCritSectEnter(&pHeap->CritSect);
+                    }
+                }
+            }
+            else
+                rc = VERR_INVALID_POINTER;
+        }
+        else
+            rc = VERR_INVALID_POINTER;
+
+        RTCritSectLeave(&pHeap->CritSect);
+    }
+
+    return rc;
+}
+
+
+/**
+ * Initializes the heap.
+ *
+ * @returns IPRT status code
+ * @param   pvUser              Unused.
+ */
+static DECLCALLBACK(int) rtMemPagePosixInitOnce(void *pvUser)
+{
+    NOREF(pvUser);
+    int rc = RTHeapPageInit(&g_MemPagePosixHeap, false /*fExec*/);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTHeapPageInit(&g_MemExecPosixHeap, true /*fExec*/);
+        if (RT_SUCCESS(rc))
+            return rc;
+        RTHeapPageDelete(&g_MemPagePosixHeap);
+    }
+    return rc;
+}
+
+
+/**
+ * Allocates memory from the specified heap.
+ *
+ * @returns Address of the allocated memory.
+ * @param   cb                  The number of bytes to allocate.
+ * @param   pszTag              The tag.
+ * @param   fFlags              RTMEMPAGEALLOC_F_XXX.
+ * @param   pHeap               The heap to use.
+ */
+static void *rtMemPagePosixAlloc(size_t cb, const char *pszTag, uint32_t fFlags, PRTHEAPPAGE pHeap)
+{
+    /*
+     * Validate & adjust the input.
+     */
+    Assert(cb > 0);
+    NOREF(pszTag);
+    cb = RT_ALIGN_Z(cb, PAGE_SIZE);
+
+    /*
+     * If the allocation is relatively large, we use mmap/munmap directly.
+     */
+    void *pv;
+    if (cb >= RTMEMPAGEPOSIX_MMAP_THRESHOLD)
+    {
+
+        pv = mmap(NULL, cb,
+                  PROT_READ | PROT_WRITE | (pHeap == &g_MemExecPosixHeap ? PROT_EXEC : 0),
+                  MAP_PRIVATE | MAP_ANONYMOUS,
+                  -1, 0);
+        if (pv != MAP_FAILED)
+        {
+            AssertPtr(pv);
+
+            if (fFlags)
+                rtMemPagePosixApplyFlags(pv, cb, fFlags);
+        }
+        else
+            pv = NULL;
+    }
+    else
+    {
+        int rc = RTOnce(&g_MemPagePosixInitOnce, rtMemPagePosixInitOnce, NULL);
+        if (RT_SUCCESS(rc))
+            rc = RTHeapPageAlloc(pHeap, cb >> PAGE_SHIFT, pszTag, fFlags, &pv);
+        if (RT_FAILURE(rc))
+            pv = NULL;
+    }
+
+    return pv;
+}
+
+
+/**
+ * Free memory allocated by rtMemPagePosixAlloc.
+ *
+ * @param   pv                  The address of the memory to free.
+ * @param   cb                  The size.
+ * @param   pHeap               The heap.
+ */
+static void rtMemPagePosixFree(void *pv, size_t cb, PRTHEAPPAGE pHeap)
+{
+    /*
+     * Validate & adjust the input.
+     */
+    if (!pv)
+        return;
+    AssertPtr(pv);
+    Assert(cb > 0);
+    Assert(!((uintptr_t)pv & PAGE_OFFSET_MASK));
+    cb = RT_ALIGN_Z(cb, PAGE_SIZE);
+
+    /*
+     * If the allocation is relatively large, we use mmap/munmap directly.
+     */
+    if (cb >= RTMEMPAGEPOSIX_MMAP_THRESHOLD)
+    {
+        int rc = munmap(pv, cb);
+        AssertMsg(rc == 0, ("rc=%d pv=%p cb=%#zx\n", rc, pv, cb)); NOREF(rc);
+    }
+    else
+    {
+        int rc = RTHeapPageFree(pHeap, pv, cb >> PAGE_SHIFT);
+        AssertRC(rc);
+    }
+}
+
+
+
+
+
+RTDECL(void *) RTMemPageAllocTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixAlloc(cb, pszTag, 0, &g_MemPagePosixHeap);
+}
+
+
+RTDECL(void *) RTMemPageAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixAlloc(cb, pszTag, RTMEMPAGEALLOC_F_ZERO, &g_MemPagePosixHeap);
+}
+
+
+RTDECL(void *) RTMemPageAllocExTag(size_t cb, uint32_t fFlags, const char *pszTag) RT_NO_THROW_DEF
+{
+    AssertReturn(!(fFlags & ~RTMEMPAGEALLOC_F_VALID_MASK), NULL);
+    return rtMemPagePosixAlloc(cb, pszTag, fFlags, &g_MemPagePosixHeap);
+}
+
+
+RTDECL(void) RTMemPageFree(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixFree(pv, cb, &g_MemPagePosixHeap);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-posix.cpp b/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-posix.cpp
new file mode 100644
index 00000000..abe285a2
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/rtmempage-exec-mmap-posix.cpp
@@ -0,0 +1,182 @@
+/* $Id: rtmempage-exec-mmap-posix.cpp $ */
+/** @file
+ * IPRT - RTMemPage*, POSIX with mmap only.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/mem.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/mman.h>
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
+
+/**
+ * Applies flags to an allocation.
+ *
+ * @param   pv              The allocation.
+ * @param   cb              The size of the allocation (page aligned).
+ * @param   fFlags          RTMEMPAGEALLOC_F_XXX.
+ */
+DECLINLINE(void) rtMemPagePosixApplyFlags(void *pv, size_t cb, uint32_t fFlags)
+{
+#ifndef RT_OS_OS2
+    if (fFlags & RTMEMPAGEALLOC_F_ADVISE_LOCKED)
+    {
+        int rc = mlock(pv, cb);
+# ifndef RT_OS_SOLARIS /* mlock(3C) on Solaris requires the priv_lock_memory privilege */
+        AssertMsg(rc == 0, ("mlock %p LB %#zx -> %d errno=%d\n", pv, cb, rc, errno));
+# endif
+        NOREF(rc);
+    }
+
+# ifdef MADV_DONTDUMP
+    if (fFlags & RTMEMPAGEALLOC_F_ADVISE_NO_DUMP)
+    {
+        int rc = madvise(pv, cb, MADV_DONTDUMP);
+        AssertMsg(rc == 0, ("madvice %p LB %#zx MADV_DONTDUMP -> %d errno=%d\n", pv, cb, rc, errno));
+        NOREF(rc);
+    }
+# endif
+#endif
+
+    if (fFlags & RTMEMPAGEALLOC_F_ZERO)
+        RT_BZERO(pv, cb);
+}
+
+
+/**
+ * Allocates memory from the specified heap.
+ *
+ * @returns Address of the allocated memory.
+ * @param   cb                  The number of bytes to allocate.
+ * @param   pszTag              The tag.
+ * @param   fFlags              RTMEMPAGEALLOC_F_XXX.
+ * @param   fProtExec           PROT_EXEC or 0.
+ */
+static void *rtMemPagePosixAlloc(size_t cb, const char *pszTag, uint32_t fFlags, int fProtExec)
+{
+    /*
+     * Validate & adjust the input.
+     */
+    Assert(cb > 0);
+    NOREF(pszTag);
+    cb = RT_ALIGN_Z(cb, PAGE_SIZE);
+
+    /*
+     * Do the allocation.
+     */
+    void *pv = mmap(NULL, cb,
+                    PROT_READ | PROT_WRITE | fProtExec,
+                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+    if (pv != MAP_FAILED)
+    {
+        AssertPtr(pv);
+
+        if (fFlags)
+            rtMemPagePosixApplyFlags(pv, cb, fFlags);
+    }
+    else
+        pv = NULL;
+
+    return pv;
+}
+
+
+/**
+ * Free memory allocated by rtMemPagePosixAlloc.
+ *
+ * @param   pv                  The address of the memory to free.
+ * @param   cb                  The size.
+ */
+static void rtMemPagePosixFree(void *pv, size_t cb)
+{
+    /*
+     * Validate & adjust the input.
+     */
+    if (!pv)
+        return;
+    AssertPtr(pv);
+    Assert(cb > 0);
+    Assert(!((uintptr_t)pv & PAGE_OFFSET_MASK));
+    cb = RT_ALIGN_Z(cb, PAGE_SIZE);
+
+    /*
+     * Free the memory.
+     */
+    int rc = munmap(pv, cb);
+    AssertMsg(rc == 0, ("rc=%d pv=%p cb=%#zx\n", rc, pv, cb)); NOREF(rc);
+}
+
+
+
+
+
+RTDECL(void *) RTMemPageAllocTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixAlloc(cb, pszTag, 0, 0);
+}
+
+
+RTDECL(void *) RTMemPageAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixAlloc(cb, pszTag, RTMEMPAGEALLOC_F_ZERO, 0);
+}
+
+
+RTDECL(void *) RTMemPageAllocExTag(size_t cb, uint32_t fFlags, const char *pszTag) RT_NO_THROW_DEF
+{
+    AssertReturn(!(fFlags & ~RTMEMPAGEALLOC_F_VALID_MASK), NULL);
+    return rtMemPagePosixAlloc(cb, pszTag, fFlags, 0);
+}
+
+
+RTDECL(void) RTMemPageFree(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    return rtMemPagePosixFree(pv, cb);
+}
+
diff --git a/src/VBox/Runtime/r3/posix/sched-posix.cpp b/src/VBox/Runtime/r3/posix/sched-posix.cpp
new file mode 100644
index 00000000..b30b9c67
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/sched-posix.cpp
@@ -0,0 +1,849 @@
+/* $Id: sched-posix.cpp $ */
+/** @file
+ * IPRT - Scheduling, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/*
+ * !WARNING!
+ *
+ * When talking about lowering and raising priority, we do *NOT* refer to
+ * the common direction priority values takes on unix systems (lower means
+ * higher). So, when we raise the priority of a linux thread the nice
+ * value will decrease, and when we lower the priority the nice value
+ * will increase. Confusing, right?
+ *
+ * !WARNING!
+ */
+
+
+
+/** @def THREAD_LOGGING
+ * Be very careful with enabling this, it may cause deadlocks when combined
+ * with the 'thread' logging prefix.
+ */
+#ifdef DOXYGEN_RUNNING
+#define THREAD_LOGGING
+#endif
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <errno.h>
+#include <pthread.h>
+#include <sched.h>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#include <iprt/thread.h>
+#include <iprt/process.h>
+#include <iprt/semaphore.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/log.h>
+#include <iprt/err.h>
+#include "internal/sched.h"
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/** Array scheduler attributes corresponding to each of the thread types. */
+typedef struct PROCPRIORITYTYPE
+{
+    /** For sanity include the array index. */
+    RTTHREADTYPE    enmType;
+    /** The thread priority or nice delta - depends on which priority type. */
+    int             iPriority;
+} PROCPRIORITYTYPE;
+
+
+/**
+ * Configuration of one priority.
+ */
+typedef struct
+{
+    /** The priority. */
+    RTPROCPRIORITY  enmPriority;
+    /** The name of this priority. */
+    const char     *pszName;
+    /** The process nice value. */
+    int             iNice;
+    /** The delta applied to the iPriority value. */
+    int             iDelta;
+    /** Array scheduler attributes corresponding to each of the thread types. */
+    const PROCPRIORITYTYPE *paTypes;
+} PROCPRIORITY;
+
+
+/**
+ * Saved priority settings
+ */
+typedef struct
+{
+    /** Process priority. */
+    int                 iPriority;
+    /** Process level. */
+    struct sched_param  SchedParam;
+    /** Process level. */
+    int                 iPolicy;
+    /** pthread level. */
+    struct sched_param  PthreadSchedParam;
+    /** pthread level. */
+    int                 iPthreadPolicy;
+} SAVEDPRIORITY, *PSAVEDPRIORITY;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Thread level priorities based on a 0..31 priority range
+ * as specified as the minimum for SCHED_RR/FIFO. FreeBSD
+ * seems to be using this (needs more research to be
+ * certain).
+ */
+static const PROCPRIORITYTYPE g_aTypesThread[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,        5 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       12 },
+    { RTTHREADTYPE_EMULATION,               14 },
+    { RTTHREADTYPE_DEFAULT,                 15 },
+    { RTTHREADTYPE_GUI,                     16 },
+    { RTTHREADTYPE_MAIN_WORKER,             18 },
+    { RTTHREADTYPE_VRDP_IO,                 24 },
+    { RTTHREADTYPE_DEBUGGER,                28 },
+    { RTTHREADTYPE_MSG_PUMP,                29 },
+    { RTTHREADTYPE_IO,                      30 },
+    { RTTHREADTYPE_TIMER,                   31 }
+};
+
+static const PROCPRIORITYTYPE g_aTypesThreadFlat[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 ~0 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,       15 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       15 },
+    { RTTHREADTYPE_EMULATION,               15 },
+    { RTTHREADTYPE_DEFAULT,                 15 },
+    { RTTHREADTYPE_GUI,                     15 },
+    { RTTHREADTYPE_MAIN_WORKER,             15 },
+    { RTTHREADTYPE_VRDP_IO,                 15 },
+    { RTTHREADTYPE_DEBUGGER,                15 },
+    { RTTHREADTYPE_MSG_PUMP,                15 },
+    { RTTHREADTYPE_IO,                      15 },
+    { RTTHREADTYPE_TIMER,                   15 }
+};
+
+/**
+ * Process and thread level priority, full access at thread level.
+ */
+static const PROCPRIORITY   g_aProcessAndThread[] =
+{
+    { RTPROCPRIORITY_FLAT,      "Flat",      0, 0, g_aTypesThreadFlat },
+    { RTPROCPRIORITY_LOW,       "Low",       9, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",      11, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",      15, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",      17, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",      19, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",       7, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",       5, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",       3, 0, g_aTypesThread },
+    { RTPROCPRIORITY_LOW,       "Low",       1, 0, g_aTypesThread },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0, 0, g_aTypesThread },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0, 0, g_aTypesThreadFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -9, 0, g_aTypesThread },
+    { RTPROCPRIORITY_HIGH,      "High",     -7, 0, g_aTypesThread },
+    { RTPROCPRIORITY_HIGH,      "High",     -5, 0, g_aTypesThread },
+    { RTPROCPRIORITY_HIGH,      "High",     -3, 0, g_aTypesThread },
+    { RTPROCPRIORITY_HIGH,      "High",     -1, 0, g_aTypesThread },
+    { RTPROCPRIORITY_HIGH,      "High",     -9, 0, g_aTypesThreadFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -1, 0, g_aTypesThreadFlat }
+};
+
+/**
+ * Deltas for a process in which we are not restricted
+ * to only be lowering the priority.
+ */
+static const PROCPRIORITYTYPE g_aTypesUnixFree[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,       +3 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       +2 },
+    { RTTHREADTYPE_EMULATION,               +1 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                 -1 },
+    { RTTHREADTYPE_DEBUGGER,                -1 },
+    { RTTHREADTYPE_MSG_PUMP,                -2 },
+    { RTTHREADTYPE_IO,                      -3 },
+    { RTTHREADTYPE_TIMER,                   -4 }
+};
+
+/**
+ * Deltas for a process in which we are restricted
+ * to only be lowering the priority.
+ */
+static const PROCPRIORITYTYPE g_aTypesUnixRestricted[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,       +3 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,       +2 },
+    { RTTHREADTYPE_EMULATION,               +1 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                  0 },
+    { RTTHREADTYPE_DEBUGGER,                 0 },
+    { RTTHREADTYPE_MSG_PUMP,                 0 },
+    { RTTHREADTYPE_IO,                       0 },
+    { RTTHREADTYPE_TIMER,                    0 }
+};
+
+/**
+ * Deltas for a process in which we are restricted
+ * to only be lowering the priority.
+ */
+static const PROCPRIORITYTYPE g_aTypesUnixFlat[RTTHREADTYPE_END] =
+{
+    { RTTHREADTYPE_INVALID,                 -999999999 },
+    { RTTHREADTYPE_INFREQUENT_POLLER,        0 },
+    { RTTHREADTYPE_MAIN_HEAVY_WORKER,        0 },
+    { RTTHREADTYPE_EMULATION,                0 },
+    { RTTHREADTYPE_DEFAULT,                  0 },
+    { RTTHREADTYPE_GUI,                      0 },
+    { RTTHREADTYPE_MAIN_WORKER,              0 },
+    { RTTHREADTYPE_VRDP_IO,                  0 },
+    { RTTHREADTYPE_DEBUGGER,                 0 },
+    { RTTHREADTYPE_MSG_PUMP,                 0 },
+    { RTTHREADTYPE_IO,                       0 },
+    { RTTHREADTYPE_TIMER,                    0 }
+};
+
+/**
+ * Process and thread level priority, full access at thread level.
+ */
+static const PROCPRIORITY   g_aUnixConfigs[] =
+{
+    { RTPROCPRIORITY_FLAT,      "Flat",      0,   0, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesUnixFree },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesUnixFree },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesUnixFree },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_LOW,       "Low",      19,  19, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_LOW,       "Low",       9,   9, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_LOW,       "Low",      15,  15, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_LOW,       "Low",      17,  17, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesUnixFree },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_NORMAL,    "Normal",    0,   0, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesUnixFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesUnixFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesUnixFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesUnixFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesUnixFree },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesUnixRestricted },
+    { RTPROCPRIORITY_HIGH,      "High",     -9,  -9, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -7,  -7, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -5,  -5, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -3,  -3, g_aTypesUnixFlat },
+    { RTPROCPRIORITY_HIGH,      "High",     -1,  -1, g_aTypesUnixFlat }
+};
+
+/**
+ * The dynamic default priority configuration.
+ *
+ * This will be recalulated at runtime depending on what the
+ * system allow us to do and what the current priority is.
+ */
+static PROCPRIORITY g_aDefaultPriority =
+{
+    RTPROCPRIORITY_LOW, "Default", 0, 0, g_aTypesUnixRestricted
+};
+
+/** Pointer to the current priority configuration. */
+static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
+
+
+/** Set to what kind of scheduling priority support the host
+ * OS seems to be offering. Determined at runtime.
+ */
+static enum
+{
+    OSPRIOSUP_UNDETERMINED = 0,
+    /** An excellent combination of process and thread level
+     * I.e. setpriority() works on process level, one have to be supervisor
+     * to raise priority as is the custom in unix. While pthread_setschedparam()
+     * works on thread level and we can raise the priority just like we want.
+     *
+     * I think this is what FreeBSD offers. (It is certainly analogous to what
+     * NT offers if you wondered.) Linux on the other hand doesn't provide this
+     * for processes with SCHED_OTHER policy, and I'm not sure if we want to
+     * play around with using the real-time SCHED_RR and SCHED_FIFO which would
+     * require special privileges anyway.
+     */
+    OSPRIOSUP_PROCESS_AND_THREAD_LEVEL,
+    /** A rough thread level priority only.
+     * setpriority() is the only real game in town, and it works on thread level.
+     */
+    OSPRIOSUP_THREAD_LEVEL
+}   volatile g_enmOsPrioSup = OSPRIOSUP_UNDETERMINED;
+
+/** Set if we figure we have nice capability, meaning we can use setpriority
+ * to raise the priority. */
+static bool g_fCanNice = false;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+
+/**
+ * Saves all the scheduling attributes we can think of.
+ */
+static void rtSchedNativeSave(PSAVEDPRIORITY pSave)
+{
+    memset(pSave, 0xff, sizeof(*pSave));
+
+    errno = 0;
+    pSave->iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
+    Assert(errno == 0);
+
+    errno = 0;
+    sched_getparam(0 /* current process */, &pSave->SchedParam);
+    Assert(errno == 0);
+
+    errno = 0;
+    pSave->iPolicy = sched_getscheduler(0 /* current process */);
+    Assert(errno == 0);
+
+    int rc = pthread_getschedparam(pthread_self(), &pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
+    Assert(rc == 0); NOREF(rc);
+}
+
+
+/**
+ * Restores scheduling attributes.
+ * Most of this won't work right, but anyway...
+ */
+static void rtSchedNativeRestore(PSAVEDPRIORITY pSave)
+{
+    setpriority(PRIO_PROCESS, 0, pSave->iPriority);
+    sched_setscheduler(0, pSave->iPolicy, &pSave->SchedParam);
+    sched_setparam(0, &pSave->SchedParam);
+    pthread_setschedparam(pthread_self(), pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
+}
+
+
+/**
+ * Starts a worker thread and wait for it to complete.
+ * We cannot use RTThreadCreate since we're already owner of the RW lock.
+ */
+static int rtSchedCreateThread(void *(*pfnThread)(void *pvArg), void *pvArg)
+{
+    /*
+     * Setup thread attributes.
+     */
+    pthread_attr_t  ThreadAttr;
+    int rc = pthread_attr_init(&ThreadAttr);
+    if (!rc)
+    {
+        rc = pthread_attr_setdetachstate(&ThreadAttr, PTHREAD_CREATE_JOINABLE);
+        if (!rc)
+        {
+            rc = pthread_attr_setstacksize(&ThreadAttr, 128*1024);
+            if (!rc)
+            {
+                /*
+                 * Create the thread.
+                 */
+                pthread_t Thread;
+                rc = pthread_create(&Thread, &ThreadAttr, pfnThread, pvArg);
+                if (!rc)
+                {
+                    pthread_attr_destroy(&ThreadAttr);
+                    /*
+                     * Wait for the thread to finish.
+                     */
+                    void *pvRet = (void *)-1;
+                    do
+                    {
+                        rc = pthread_join(Thread, &pvRet);
+                    } while (rc == EINTR);
+                    if (rc)
+                        return RTErrConvertFromErrno(rc);
+                    return (int)(uintptr_t)pvRet;
+                }
+            }
+        }
+        pthread_attr_destroy(&ThreadAttr);
+    }
+    return RTErrConvertFromErrno(rc);
+}
+
+
+static void rtSchedDumpPriority(void)
+{
+#ifdef THREAD_LOGGING
+    Log(("Priority: g_fCanNice=%d g_enmOsPrioSup=%d\n", g_fCanNice, g_enmOsPrioSup));
+    Log(("Priority: enmPriority=%d \"%s\" iNice=%d iDelta=%d\n",
+         g_pProcessPriority->enmPriority,
+         g_pProcessPriority->pszName,
+         g_pProcessPriority->iNice,
+         g_pProcessPriority->iDelta));
+    Log(("Priority:  %2d INFREQUENT_POLLER = %d\n", RTTHREADTYPE_INFREQUENT_POLLER, g_pProcessPriority->paTypes[RTTHREADTYPE_INFREQUENT_POLLER].iPriority));
+    Log(("Priority:  %2d MAIN_HEAVY_WORKER = %d\n", RTTHREADTYPE_MAIN_HEAVY_WORKER, g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_HEAVY_WORKER].iPriority));
+    Log(("Priority:  %2d EMULATION         = %d\n", RTTHREADTYPE_EMULATION        , g_pProcessPriority->paTypes[RTTHREADTYPE_EMULATION        ].iPriority));
+    Log(("Priority:  %2d DEFAULT           = %d\n", RTTHREADTYPE_DEFAULT          , g_pProcessPriority->paTypes[RTTHREADTYPE_DEFAULT          ].iPriority));
+    Log(("Priority:  %2d GUI               = %d\n", RTTHREADTYPE_GUI              , g_pProcessPriority->paTypes[RTTHREADTYPE_GUI              ].iPriority));
+    Log(("Priority:  %2d MAIN_WORKER       = %d\n", RTTHREADTYPE_MAIN_WORKER      , g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_WORKER      ].iPriority));
+    Log(("Priority:  %2d VRDP_IO           = %d\n", RTTHREADTYPE_VRDP_IO          , g_pProcessPriority->paTypes[RTTHREADTYPE_VRDP_IO          ].iPriority));
+    Log(("Priority:  %2d DEBUGGER          = %d\n", RTTHREADTYPE_DEBUGGER         , g_pProcessPriority->paTypes[RTTHREADTYPE_DEBUGGER         ].iPriority));
+    Log(("Priority:  %2d MSG_PUMP          = %d\n", RTTHREADTYPE_MSG_PUMP         , g_pProcessPriority->paTypes[RTTHREADTYPE_MSG_PUMP         ].iPriority));
+    Log(("Priority:  %2d IO                = %d\n", RTTHREADTYPE_IO               , g_pProcessPriority->paTypes[RTTHREADTYPE_IO               ].iPriority));
+    Log(("Priority:  %2d TIMER             = %d\n", RTTHREADTYPE_TIMER            , g_pProcessPriority->paTypes[RTTHREADTYPE_TIMER            ].iPriority));
+#endif
+}
+
+
+/**
+ * The prober thread.
+ * We don't want to mess with the priority of the calling thread.
+ *
+ * @remark  This is pretty presumptive stuff, but if it works on Linux and
+ *          FreeBSD it does what I want.
+ */
+static void *rtSchedNativeProberThread(void *pvUser)
+{
+    SAVEDPRIORITY SavedPriority;
+    rtSchedNativeSave(&SavedPriority);
+
+    /*
+     * Let's first try and see what we get on a thread level.
+     */
+    int iMax = sched_get_priority_max(SavedPriority.iPthreadPolicy);
+    int iMin = sched_get_priority_min(SavedPriority.iPthreadPolicy);
+    if (iMax - iMin >= 32)
+    {
+        pthread_t Self = pthread_self();
+        int i = iMin;
+        while (i <= iMax)
+        {
+            struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
+            SchedParam.sched_priority = i;
+            if (pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam))
+                break;
+            i++;
+        }
+        if (i == iMax)
+            g_enmOsPrioSup = OSPRIOSUP_PROCESS_AND_THREAD_LEVEL;
+    }
+
+    /*
+     * Ok, we didn't have the good stuff, so let's fall back on the unix stuff.
+     */
+    if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
+        g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
+
+    /*
+     * Check if we can get higher priority (typically only root can do this).
+     * (Won't work right if our priority is -19 to start with, but what the heck.)
+     *
+     * We assume that the unix priority is -19 to 19. I know there are defines
+     * for this, but I don't remember which and if I'm awake enough to make sense
+     * of them from any SuS spec.
+     */
+    int iStart = getpriority(PRIO_PROCESS, 0);
+    int i = iStart;
+    while (i-- > -19)
+    {
+        if (setpriority(PRIO_PROCESS, 0, i))
+            break;
+    }
+    if (getpriority(PRIO_PROCESS, 0) != iStart)
+        g_fCanNice = true;
+    else
+        g_fCanNice = false;
+
+    /* done */
+    rtSchedNativeRestore(&SavedPriority);
+    RT_NOREF(pvUser);
+    return (void *)VINF_SUCCESS;
+}
+
+
+/**
+ * Calculate the scheduling properties for all the threads in the default
+ * process priority, assuming the current thread have the type enmType.
+ *
+ * @returns iprt status code.
+ * @param   enmType     The thread type to be assumed for the current thread.
+ */
+DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+
+    /*
+     * First figure out what's supported by the OS.
+     */
+    if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
+    {
+        int iPriority = getpriority(PRIO_PROCESS, 0);
+        int rc = rtSchedCreateThread(rtSchedNativeProberThread, NULL);
+        if (RT_FAILURE(rc))
+            return rc;
+        if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
+            g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
+        Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
+    }
+
+    /*
+     * Now let's see what we can do...
+     */
+    int iPriority = getpriority(PRIO_PROCESS, 0);
+    switch (g_enmOsPrioSup)
+    {
+        case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
+        {
+            g_aDefaultPriority.iNice = iPriority;
+            g_aDefaultPriority.iDelta = 0;
+            g_aDefaultPriority.paTypes = g_aTypesThread;
+            Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
+            break;
+        }
+
+        case OSPRIOSUP_THREAD_LEVEL:
+        {
+            if (g_fCanNice)
+                g_aDefaultPriority.paTypes = g_aTypesUnixFree;
+            else
+                g_aDefaultPriority.paTypes = g_aTypesUnixRestricted;
+            Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
+            g_aDefaultPriority.iNice = iPriority - g_aDefaultPriority.paTypes[enmType].iPriority;
+            g_aDefaultPriority.iDelta = g_aDefaultPriority.iNice;
+            break;
+        }
+
+        default:
+            AssertFailed();
+            break;
+    }
+    rtSchedDumpPriority();
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The validator thread.
+ * We don't want to mess with the priority of the calling thread.
+ *
+ * @remark  This is pretty presumptive stuff, but if it works on Linux and
+ *          FreeBSD it does what I want.
+ */
+static void *rtSchedNativeValidatorThread(void *pvUser)
+{
+    const PROCPRIORITY *pCfg = (const PROCPRIORITY *)pvUser;
+    SAVEDPRIORITY SavedPriority;
+    rtSchedNativeSave(&SavedPriority);
+
+    int rc = VINF_SUCCESS;
+    switch (g_enmOsPrioSup)
+    {
+        /*
+         * Try set the specified process priority and then try
+         * out all the thread priorities which are used.
+         */
+        case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
+        {
+            if (!setpriority(PRIO_PROCESS, 0, pCfg->iNice))
+            {
+                int iMin = sched_get_priority_min(SavedPriority.iPolicy);
+                pthread_t Self = pthread_self();
+                for (int i = RTTHREADTYPE_INVALID + 1; i < RTTHREADTYPE_END; i++)
+                {
+                    struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
+                    SchedParam.sched_priority = pCfg->paTypes[i].iPriority
+                        + pCfg->iDelta + iMin;
+                    rc = pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam);
+                    if (rc)
+                    {
+                        rc = RTErrConvertFromErrno(rc);
+                        break;
+                    }
+                }
+            }
+            else
+                rc = RTErrConvertFromErrno(errno);
+            break;
+        }
+
+        /*
+         * Try out the priorities from the top and down.
+         */
+        case OSPRIOSUP_THREAD_LEVEL:
+        {
+            int i = RTTHREADTYPE_END;
+            while (--i > RTTHREADTYPE_INVALID)
+            {
+                int iPriority = pCfg->paTypes[i].iPriority + pCfg->iDelta;
+                if (setpriority(PRIO_PROCESS, 0, iPriority))
+                {
+                    rc = RTErrConvertFromErrno(errno);
+                    break;
+                }
+            }
+            break;
+        }
+
+        default:
+            AssertFailed();
+            break;
+    }
+
+    /* done */
+    rtSchedNativeRestore(&SavedPriority);
+    return (void *)(intptr_t)rc;
+}
+
+
+DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
+{
+    Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
+
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+    /*
+     * Make sure the proxy creation thread is started so we don't 'lose' our
+     * initial priority if it's lowered.
+     */
+    rtThreadPosixPriorityProxyStart();
+#endif
+
+    /*
+     * Nothing to validate for the default priority (assuming no external renice).
+     */
+    int rc = VINF_SUCCESS;
+    if (enmPriority == RTPROCPRIORITY_DEFAULT)
+        g_pProcessPriority = &g_aDefaultPriority;
+    else
+    {
+        /*
+         * Select the array to search.
+         */
+        const PROCPRIORITY *pa;
+        unsigned            c;
+        switch (g_enmOsPrioSup)
+        {
+            case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
+                pa = g_aProcessAndThread;
+                c = RT_ELEMENTS(g_aProcessAndThread);
+                break;
+            case OSPRIOSUP_THREAD_LEVEL:
+                pa = g_aUnixConfigs;
+                c = RT_ELEMENTS(g_aUnixConfigs);
+                break;
+            default:
+                pa = NULL;
+                c = 0;
+                break;
+        }
+
+        /*
+         * Search the array.
+         */
+        rc = VERR_FILE_NOT_FOUND;
+        unsigned i;
+        for (i = 0; i < c; i++)
+        {
+            if (pa[i].enmPriority == enmPriority)
+            {
+                /*
+                 * Validate it.
+                 */
+                int iPriority = getpriority(PRIO_PROCESS, 0);
+                int rc3 = rtSchedCreateThread(rtSchedNativeValidatorThread, (void *)&pa[i]);
+                Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
+                if (RT_SUCCESS(rc))
+                    rc = rc3;
+                if (RT_SUCCESS(rc))
+                    break;
+            }
+        }
+
+        /*
+         * Did we get lucky?
+         * If so update process priority and globals.
+         */
+        if (RT_SUCCESS(rc))
+        {
+            switch (g_enmOsPrioSup)
+            {
+                case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
+                    if (setpriority(PRIO_PROCESS, 0, pa[i].iNice))
+                    {
+                        rc = RTErrConvertFromErrno(errno);
+                        AssertMsgFailed(("setpriority(,,%d) -> errno=%d rc=%Rrc\n", pa[i].iNice, errno, rc));
+                    }
+                    break;
+
+                default:
+                    break;
+            }
+
+            if (RT_SUCCESS(rc))
+                g_pProcessPriority = &pa[i];
+        }
+    }
+
+#ifdef THREAD_LOGGING
+    LogFlow(("rtProcNativeSetPriority: returns %Rrc enmPriority=%d\n", rc, enmPriority));
+    rtSchedDumpPriority();
+#endif
+    return rc;
+}
+
+
+/**
+ * Worker for rtThreadNativeSetPriority/OSPRIOSUP_PROCESS_AND_THREAD_LEVEL
+ * that's either called on the priority proxy thread or directly if no proxy.
+ */
+static DECLCALLBACK(int) rtThreadPosixSetPriorityOnProcAndThrdCallback(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    struct sched_param  SchedParam = {-9999999};
+    int                 iPolicy = -7777777;
+    int rc = pthread_getschedparam((pthread_t)pThread->Core.Key, &iPolicy, &SchedParam);
+    if (!rc)
+    {
+        SchedParam.sched_priority = g_pProcessPriority->paTypes[enmType].iPriority
+            + g_pProcessPriority->iDelta
+            + sched_get_priority_min(iPolicy);
+
+        rc = pthread_setschedparam((pthread_t)pThread->Core.Key, iPolicy, &SchedParam);
+        if (!rc)
+        {
+#ifdef THREAD_LOGGING
+            Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPolicy=%d sched_priority=%d pid=%d\n",
+                 pThread->Core.Key, enmType, iPolicy, SchedParam.sched_priority, getpid()));
+#endif
+            return VINF_SUCCESS;
+        }
+    }
+
+    int rcNative = rc;
+    rc = RTErrConvertFromErrno(rc);
+    AssertMsgFailed(("pthread_[gs]etschedparam(%p, %d, {%d}) -> rcNative=%d rc=%Rrc\n",
+                     (void *)pThread->Core.Key, iPolicy, SchedParam.sched_priority, rcNative, rc)); NOREF(rcNative);
+    return rc;
+}
+
+
+DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    Assert(enmType == g_pProcessPriority->paTypes[enmType].enmType);
+
+    int rc = VINF_SUCCESS;
+    switch (g_enmOsPrioSup)
+    {
+        case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
+        {
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+            if (rtThreadPosixPriorityProxyStart())
+                rc = rtThreadPosixPriorityProxyCall(pThread, (PFNRT)rtThreadPosixSetPriorityOnProcAndThrdCallback,
+                                                    2, pThread, enmType);
+            else
+#endif
+                rc = rtThreadPosixSetPriorityOnProcAndThrdCallback(pThread, enmType);
+            break;
+        }
+
+        case OSPRIOSUP_THREAD_LEVEL:
+        {
+            /* No cross platform way of getting the 'who' parameter value for
+               arbitrary threads, so this is restricted to the calling thread only. */
+            AssertReturn((pthread_t)pThread->Core.Key == pthread_self(), VERR_NOT_SUPPORTED);
+
+            int iPriority = g_pProcessPriority->paTypes[enmType].iPriority + g_pProcessPriority->iDelta;
+            if (!setpriority(PRIO_PROCESS, 0, iPriority))
+            {
+                AssertMsg(iPriority == getpriority(PRIO_PROCESS, 0), ("iPriority=%d getpriority()=%d\n", iPriority, getpriority(PRIO_PROCESS, 0)));
+#ifdef THREAD_LOGGING
+                Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPriority=%d pid=%d\n", pThread->Core.Key, enmType, iPriority, getpid()));
+#endif
+            }
+            else
+            {
+#if 0
+                rc = RTErrConvertFromErrno(errno);
+                AssertMsgFailed(("setpriority(,, %d) -> errno=%d rc=%Rrc\n", iPriority, errno, rc));
+#else
+                /** @todo
+                 * Just keep quiet about failures now - we'll fail here because we're not
+                 * allowed to raise our own priority. This is a problem when starting the
+                 * threads with higher priority from EMT (i.e. most threads it starts).
+                 * This is apparently inherited from the parent in some cases and not
+                 * in other cases. I guess this would come down to which kind of pthread
+                 * implementation is actually in use, and how many sensible patches which
+                 * are installed.
+                 * I need to find a system where this problem shows up in order to come up
+                 * with a proper fix. There's an pthread_create attribute for not inheriting
+                 * scheduler stuff I think...
+                 */
+                rc = VINF_SUCCESS;
+#endif
+            }
+            break;
+        }
+
+        /*
+         * Any thread created before we determine the default config, remains unchanged!
+         * The prober thread above is one of those.
+         */
+        default:
+            break;
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/semevent-posix.cpp b/src/VBox/Runtime/r3/posix/semevent-posix.cpp
new file mode 100644
index 00000000..96d01bac
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/semevent-posix.cpp
@@ -0,0 +1,654 @@
+/* $Id: semevent-posix.cpp $ */
+/** @file
+ * IPRT - Event Semaphore, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/time.h>
+
+#include "internal/mem.h"
+#include "internal/strict.h"
+
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sched.h>
+
+#include "semwait.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/** Internal representation of the POSIX implementation of an Event semaphore.
+ * The POSIX implementation uses a mutex and a condition variable to implement
+ * the automatic reset event semaphore semantics.
+ */
+struct RTSEMEVENTINTERNAL
+{
+    /** pthread condition. */
+    pthread_cond_t      Cond;
+    /** pthread mutex which protects the condition and the event state. */
+    pthread_mutex_t     Mutex;
+    /** The state of the semaphore.
+     * This is operated while owning mutex and using atomic updating. */
+    volatile uint32_t   u32State;
+    /** Number of waiters. */
+    volatile uint32_t   cWaiters;
+#ifdef RTSEMEVENT_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+    /** The creation flags. */
+    uint32_t            fFlags;
+    /** Set if we're using the monotonic clock. */
+    bool                fMonotonicClock;
+};
+
+/** The values of the u32State variable in a RTSEMEVENTINTERNAL.
+ * @{ */
+/** The object isn't initialized. */
+#define EVENT_STATE_UNINITIALIZED   0
+/** The semaphore is signaled. */
+#define EVENT_STATE_SIGNALED        0xff00ff00
+/** The semaphore is not signaled. */
+#define EVENT_STATE_NOT_SIGNALED    0x00ff00ff
+/** @} */
+
+
+RTDECL(int)  RTSemEventCreate(PRTSEMEVENT phEventSem)
+{
+    return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
+    Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
+
+    /*
+     * Allocate semaphore handle.
+     */
+    int rc;
+    struct RTSEMEVENTINTERNAL *pThis;
+    if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        pThis = (struct RTSEMEVENTINTERNAL *)RTMemAlloc(sizeof(*pThis));
+    else
+        pThis = (struct RTSEMEVENTINTERNAL *)rtMemBaseAlloc(sizeof(*pThis));
+    if (pThis)
+    {
+        /*
+         * Create the condition variable.
+         */
+        pthread_condattr_t CondAttr;
+        rc = pthread_condattr_init(&CondAttr);
+        if (!rc)
+        {
+#if defined(CLOCK_MONOTONIC) && defined(IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK)
+            /* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
+            rc = pthread_condattr_setclock(&CondAttr, CLOCK_MONOTONIC);
+            pThis->fMonotonicClock = rc == 0;
+#else
+            pThis->fMonotonicClock = false;
+#endif
+            rc = pthread_cond_init(&pThis->Cond, &CondAttr);
+            if (!rc)
+            {
+                /*
+                 * Create the semaphore.
+                 */
+                rc = pthread_mutex_init(&pThis->Mutex, NULL);
+                if (!rc)
+                {
+                    pthread_condattr_destroy(&CondAttr);
+
+                    ASMAtomicWriteU32(&pThis->u32State, EVENT_STATE_NOT_SIGNALED);
+                    ASMAtomicWriteU32(&pThis->cWaiters, 0);
+                    pThis->fFlags = fFlags;
+#ifdef RTSEMEVENT_STRICT
+                    if (!pszNameFmt)
+                    {
+                        static uint32_t volatile s_iSemEventAnon = 0;
+                        RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                                     true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                                     "RTSemEvent-%u", ASMAtomicIncU32(&s_iSemEventAnon) - 1);
+                    }
+                    else
+                    {
+                        va_list va;
+                        va_start(va, pszNameFmt);
+                        RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                                      true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                                      pszNameFmt, va);
+                        va_end(va);
+                    }
+                    pThis->fEverHadSignallers = false;
+#else
+                    RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
+#endif
+
+                    *phEventSem = pThis;
+                    return VINF_SUCCESS;
+                }
+                pthread_cond_destroy(&pThis->Cond);
+            }
+            pthread_condattr_destroy(&CondAttr);
+        }
+
+        rc = RTErrConvertFromErrno(rc);
+        if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+            RTMemFree(pThis);
+        else
+            rtMemBaseFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventDestroy(RTSEMEVENT hEventSem)
+{
+    /*
+     * Validate handle.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    if (pThis == NIL_RTSEMEVENT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t    u32 = pThis->u32State;
+    AssertReturn(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED, VERR_INVALID_HANDLE);
+
+    /*
+     * Abort all waiters forcing them to return failure.
+     */
+    int rc;
+    for (int i = 30; i > 0; i--)
+    {
+        ASMAtomicWriteU32(&pThis->u32State, EVENT_STATE_UNINITIALIZED);
+        rc = pthread_cond_destroy(&pThis->Cond);
+        if (rc != EBUSY)
+            break;
+        pthread_cond_broadcast(&pThis->Cond);
+        usleep(1000);
+    }
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d.\n", pThis, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Destroy the semaphore
+     * If it's busy we'll wait a bit to give the threads a chance to be scheduled.
+     */
+    for (int i = 30; i > 0; i--)
+    {
+        rc = pthread_mutex_destroy(&pThis->Mutex);
+        if (rc != EBUSY)
+            break;
+        usleep(1000);
+    }
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d. (mutex)\n", pThis, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Free the semaphore memory and be gone.
+     */
+#ifdef RTSEMEVENT_STRICT
+    RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+    if (!(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        RTMemFree(pThis);
+    else
+        rtMemBaseFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t    u32 = pThis->u32State;
+    AssertReturn(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENT_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    /*
+     * Lock the mutex semaphore.
+     */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to lock event sem %p, rc=%d.\n", hEventSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Check the state.
+     */
+    if (pThis->u32State == EVENT_STATE_NOT_SIGNALED)
+    {
+        ASMAtomicWriteU32(&pThis->u32State, EVENT_STATE_SIGNALED);
+        rc = pthread_cond_signal(&pThis->Cond);
+        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d.\n", hEventSem, rc));
+    }
+    else if (pThis->u32State == EVENT_STATE_SIGNALED)
+    {
+        rc = pthread_cond_signal(&pThis->Cond); /* give'm another kick... */
+        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d. (2)\n", hEventSem, rc));
+    }
+    else
+        rc = VERR_SEM_DESTROYED;
+
+    /*
+     * Release the mutex and return.
+     */
+    int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+    AssertMsg(!rc2, ("Failed to unlock event sem %p, rc=%d.\n", hEventSem, rc));
+    if (rc)
+        return RTErrConvertFromErrno(rc);
+    if (rc2)
+        return RTErrConvertFromErrno(rc2);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Handle polling (timeout already expired at the time of the call).
+ *
+ * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED.
+ * @param   pThis               The semaphore.
+ */
+DECLINLINE(int) rtSemEventPosixWaitPoll(struct RTSEMEVENTINTERNAL *pThis)
+{
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    AssertMsgReturn(!rc, ("Failed to lock event sem %p, rc=%d.\n", pThis, rc), RTErrConvertFromErrno(rc));
+
+    uint32_t u32OldState;
+    bool fSuccess = ASMAtomicCmpXchgExU32(&pThis->u32State, EVENT_STATE_NOT_SIGNALED, EVENT_STATE_SIGNALED, &u32OldState);
+
+    rc = pthread_mutex_unlock(&pThis->Mutex);
+    AssertMsg(!rc, ("Failed to unlock event sem %p, rc=%d.\n", pThis, rc)); NOREF(rc);
+
+    return fSuccess
+         ? VINF_SUCCESS
+         : u32OldState != EVENT_STATE_UNINITIALIZED
+         ? VERR_TIMEOUT
+         : VERR_SEM_DESTROYED;
+}
+
+
+/**
+ * Performs an indefinite wait on the event.
+ */
+static int rtSemEventPosixWaitIndefinite(struct RTSEMEVENTINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    RT_NOREF_PV(pSrcPos);
+
+    /* for fairness, yield before going to sleep. */
+    if (    ASMAtomicIncU32(&pThis->cWaiters) > 1
+        &&  pThis->u32State == EVENT_STATE_SIGNALED)
+        sched_yield();
+
+     /* take mutex */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    if (rc)
+    {
+        ASMAtomicDecU32(&pThis->cWaiters);
+        AssertMsgFailed(("Failed to lock event sem %p, rc=%d.\n", pThis, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    for (;;)
+    {
+        /* check state. */
+        if (pThis->u32State == EVENT_STATE_SIGNALED)
+        {
+            ASMAtomicWriteU32(&pThis->u32State, EVENT_STATE_NOT_SIGNALED);
+            ASMAtomicDecU32(&pThis->cWaiters);
+            rc = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc, ("Failed to unlock event sem %p, rc=%d.\n", pThis, rc)); NOREF(rc);
+            return VINF_SUCCESS;
+        }
+        if (pThis->u32State == EVENT_STATE_UNINITIALIZED)
+        {
+            rc = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc, ("Failed to unlock event sem %p, rc=%d.\n", pThis, rc)); NOREF(rc);
+            return VERR_SEM_DESTROYED;
+        }
+
+        /* wait */
+#ifdef RTSEMEVENT_STRICT
+        RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
+                             ? RTThreadSelfAutoAdopt()
+                             : RTThreadSelf();
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT, true);
+            if (RT_FAILURE(rc))
+            {
+                ASMAtomicDecU32(&pThis->cWaiters);
+                pthread_mutex_unlock(&pThis->Mutex);
+                return rc;
+            }
+        }
+#else
+        RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
+        RT_NOREF_PV(fFlags); /** @todo interruptible wait is not implementable... */
+        rc = pthread_cond_wait(&pThis->Cond, &pThis->Mutex);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
+        if (rc)
+        {
+            AssertMsgFailed(("Failed to wait on event sem %p, rc=%d.\n", pThis, rc));
+            ASMAtomicDecU32(&pThis->cWaiters);
+            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc2, ("Failed to unlock event sem %p, rc=%d.\n", pThis, rc2)); NOREF(rc2);
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+}
+
+
+/**
+ * Performs an timed wait on the event.
+ */
+static int rtSemEventPosixWaitTimed(struct RTSEMEVENTINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout,
+                                    PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Convert the timeout specification to absolute and relative deadlines,
+     * divierting polling and infinite waits to the appropriate workers.
+     */
+    struct timespec AbsDeadline         = { 0, 0 };
+    uint64_t const  cNsRelativeDeadline = rtSemPosixCalcDeadline(fFlags, uTimeout, pThis->fMonotonicClock, &AbsDeadline);
+    if (cNsRelativeDeadline == 0)
+        return rtSemEventPosixWaitPoll(pThis);
+    if (cNsRelativeDeadline == UINT64_MAX)
+        return rtSemEventPosixWaitIndefinite(pThis, fFlags, pSrcPos);
+
+    /*
+     * Now to the business of waiting...
+     */
+
+    /* for fairness, yield before going to sleep. */
+    if (ASMAtomicIncU32(&pThis->cWaiters) > 1)
+        sched_yield();
+
+    /* take mutex */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    if (rc)
+    {
+        ASMAtomicDecU32(&pThis->cWaiters);
+        AssertMsg(rc == ETIMEDOUT, ("Failed to lock event sem %p, rc=%d.\n", pThis, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    for (;;)
+    {
+        /* check state. */
+        uint32_t const u32State = pThis->u32State;
+        if (u32State != EVENT_STATE_NOT_SIGNALED)
+        {
+            if (u32State == EVENT_STATE_SIGNALED)
+            {
+                ASMAtomicWriteU32(&pThis->u32State, EVENT_STATE_NOT_SIGNALED);
+                ASMAtomicDecU32(&pThis->cWaiters);
+                rc = VINF_SUCCESS;
+            }
+            else
+            {
+                Assert(u32State == EVENT_STATE_UNINITIALIZED);
+                rc = VERR_SEM_DESTROYED;
+            }
+            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc2, ("Failed to unlock event sem %p, rc2=%d.\n", pThis, rc2)); RT_NOREF(rc2);
+            return rc;
+        }
+
+        /* wait */
+#ifdef RTSEMEVENT_STRICT
+        RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
+                             ? RTThreadSelfAutoAdopt()
+                             : RTThreadSelf();
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       (cNsRelativeDeadline + RT_NS_1MS - 1) / RT_NS_1MS,
+                                                       RTTHREADSTATE_EVENT, true);
+            if (RT_FAILURE(rc))
+            {
+                ASMAtomicDecU32(&pThis->cWaiters);
+                pthread_mutex_unlock(&pThis->Mutex);
+                return rc;
+            }
+        }
+#else
+        RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
+        rc = pthread_cond_timedwait(&pThis->Cond, &pThis->Mutex, &AbsDeadline);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
+
+        /* According to SuS this function shall not return EINTR, but linux man page might have said differently at some point... */
+        if (   rc != 0
+            && (   rc != EINTR
+                || !(fFlags & RTSEMWAIT_FLAGS_NORESUME)))
+        {
+            AssertMsg(rc == ETIMEDOUT, ("Failed to wait on event sem %p, rc=%d.\n", pThis, rc));
+            ASMAtomicDecU32(&pThis->cWaiters);
+            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc2, ("Failed to unlock event sem %p, rc2=%d.\n", pThis, rc2)); NOREF(rc2);
+            return RTErrConvertFromErrno(rc);
+        }
+    } /* for (;;) */
+}
+
+
+/**
+ * Internal wait worker function.
+ */
+DECLINLINE(int) rtSemEventPosixWait(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t    u32 = pThis->u32State;
+    AssertReturn(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED, VERR_INVALID_HANDLE);
+    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Timed or indefinite wait?
+     */
+    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
+        return rtSemEventPosixWaitIndefinite(pThis, fFlags, pSrcPos);
+    return rtSemEventPosixWaitTimed(hEventSem, fFlags, uTimeout, pSrcPos);
+}
+
+
+RTDECL(int) RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    int rc;
+#ifndef RTSEMEVENT_STRICT
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, NULL);
+    else
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, &SrcPos);
+    else
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_RESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, &SrcPos);
+#endif
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    int rc;
+#ifndef RTSEMEVENT_STRICT
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, NULL);
+    else
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_INDEFINITE, 0, &SrcPos);
+    else
+        rc = rtSemEventPosixWait(hEventSem, RTSEMWAIT_FLAGS_NORESUME | RTSEMWAIT_FLAGS_RELATIVE | RTSEMWAIT_FLAGS_MILLISECS,
+                                 cMillies, &SrcPos);
+#endif
+    Assert(rc != VERR_INTERRUPTED);
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+    return rtSemEventPosixWait(hEventSem, fFlags, uTimeout, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemEventPosixWait(hEventSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+
+
+RTDECL(int)  RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
+                                   RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemEventPosixWait(hEventSem, fFlags, uTimeout, &SrcPos);
+}
+
+
+RTDECL(uint32_t) RTSemEventGetResolution(void)
+{
+    /** @todo we have 1ns parameter resolution, but we need to check each host
+     *        what the actual resolution might be once the parameter makes it to the
+     *        kernel and is processed there. */
+    return 1;
+}
+
+
+RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENT_STATE_NOT_SIGNALED || u32 == EVENT_STATE_SIGNALED);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/posix/semeventmulti-posix.cpp b/src/VBox/Runtime/r3/posix/semeventmulti-posix.cpp
new file mode 100644
index 00000000..52171b4a
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/semeventmulti-posix.cpp
@@ -0,0 +1,613 @@
+/* $Id: semeventmulti-posix.cpp $ */
+/** @file
+ * IPRT - Multiple Release Event Semaphore, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/time.h>
+
+#include "internal/strict.h"
+
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include "semwait.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Posix internal representation of a Mutex Multi semaphore.
+ * The POSIX implementation uses a mutex and a condition variable to implement
+ * the automatic reset event semaphore semantics. */
+struct RTSEMEVENTMULTIINTERNAL
+{
+    /** pthread condition. */
+    pthread_cond_t      Cond;
+    /** pthread mutex which protects the condition and the event state. */
+    pthread_mutex_t     Mutex;
+    /** The state of the semaphore.
+     * This is operated while owning mutex and using atomic updating. */
+    volatile uint32_t   u32State;
+    /** Number of waiters. */
+    volatile uint32_t   cWaiters;
+#ifdef RTSEMEVENTMULTI_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+    /** Set if we're using the monotonic clock. */
+    bool                fMonotonicClock;
+};
+
+/** The values of the u32State variable in RTSEMEVENTMULTIINTERNAL.
+ * @{ */
+/** The object isn't initialized. */
+#define EVENTMULTI_STATE_UNINITIALIZED   0
+/** The semaphore is signaled. */
+#define EVENTMULTI_STATE_SIGNALED        0xff00ff00
+/** The semaphore is not signaled. */
+#define EVENTMULTI_STATE_NOT_SIGNALED    0x00ff00ff
+/** @} */
+
+
+
+RTDECL(int)  RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem)
+{
+    return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
+                                     const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate semaphore handle.
+     */
+    int rc;
+    struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL));
+    if (pThis)
+    {
+        /*
+         * Create the condition variable.
+         */
+        pthread_condattr_t CondAttr;
+        rc = pthread_condattr_init(&CondAttr);
+        if (!rc)
+        {
+#if defined(CLOCK_MONOTONIC) && defined(IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK)
+            /* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
+            rc = pthread_condattr_setclock(&CondAttr, CLOCK_MONOTONIC);
+            pThis->fMonotonicClock = rc == 0;
+#else
+            pThis->fMonotonicClock = false;
+#endif
+            rc = pthread_cond_init(&pThis->Cond, &CondAttr);
+            if (!rc)
+            {
+                /*
+                 * Create the semaphore.
+                 */
+                rc = pthread_mutex_init(&pThis->Mutex, NULL);
+                if (!rc)
+                {
+                    pthread_condattr_destroy(&CondAttr);
+
+                    ASMAtomicWriteU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
+                    ASMAtomicWriteU32(&pThis->cWaiters, 0);
+#ifdef RTSEMEVENTMULTI_STRICT
+                    if (!pszNameFmt)
+                    {
+                        static uint32_t volatile s_iSemEventMultiAnon = 0;
+                        RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                                     true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                                     "RTSemEventMulti-%u", ASMAtomicIncU32(&s_iSemEventMultiAnon) - 1);
+                    }
+                    else
+                    {
+                        va_list va;
+                        va_start(va, pszNameFmt);
+                        RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                                      true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                                      pszNameFmt, va);
+                        va_end(va);
+                    }
+                    pThis->fEverHadSignallers = false;
+#else
+                    RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
+#endif
+
+                    *phEventMultiSem = pThis;
+                    return VINF_SUCCESS;
+                }
+
+                pthread_cond_destroy(&pThis->Cond);
+            }
+            pthread_condattr_destroy(&CondAttr);
+        }
+        rc = RTErrConvertFromErrno(rc);
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+
+}
+
+
+RTDECL(int)  RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate handle.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    if (pThis == NIL_RTSEMEVENTMULTI)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t u32 = pThis->u32State;
+    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);
+
+    /*
+     * Abort all waiters forcing them to return failure.
+     */
+    int rc;
+    for (int i = 30; i > 0; i--)
+    {
+        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_UNINITIALIZED);
+        rc = pthread_cond_destroy(&pThis->Cond);
+        if (rc != EBUSY)
+            break;
+        pthread_cond_broadcast(&pThis->Cond);
+        usleep(1000);
+    }
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d.\n", hEventMultiSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Destroy the semaphore
+     * If it's busy we'll wait a bit to give the threads a chance to be scheduled.
+     */
+    for (int i = 30; i > 0; i--)
+    {
+        rc = pthread_mutex_destroy(&pThis->Mutex);
+        if (rc != EBUSY)
+            break;
+        usleep(1000);
+    }
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d. (mutex)\n", hEventMultiSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Free the semaphore memory and be gone.
+     */
+#ifdef RTSEMEVENTMULTI_STRICT
+    RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t u32 = pThis->u32State;
+    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENTMULTI_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    /*
+     * Lock the mutex semaphore.
+     */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to lock event sem %p, rc=%d.\n", hEventMultiSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Check the state.
+     */
+    if (pThis->u32State == EVENTMULTI_STATE_NOT_SIGNALED)
+    {
+        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_SIGNALED);
+        rc = pthread_cond_broadcast(&pThis->Cond);
+        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d.\n", hEventMultiSem, rc));
+    }
+    else if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
+    {
+        rc = pthread_cond_broadcast(&pThis->Cond); /* give'm another kick... */
+        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d. (2)\n", hEventMultiSem, rc));
+    }
+    else
+        rc = VERR_SEM_DESTROYED;
+
+    /*
+     * Release the mutex and return.
+     */
+    int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+    AssertMsg(!rc2, ("Failed to unlock event sem %p, rc=%d.\n", hEventMultiSem, rc));
+    if (rc)
+        return RTErrConvertFromErrno(rc);
+    if (rc2)
+        return RTErrConvertFromErrno(rc2);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    int rc = VINF_SUCCESS;
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t u32 = pThis->u32State;
+    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);
+
+    /*
+     * Lock the mutex semaphore.
+     */
+    int rcPosix = pthread_mutex_lock(&pThis->Mutex);
+    if (RT_UNLIKELY(rcPosix))
+    {
+        AssertMsgFailed(("Failed to lock event multi sem %p, rc=%d.\n", hEventMultiSem, rcPosix));
+        return RTErrConvertFromErrno(rcPosix);
+    }
+
+    /*
+     * Check the state.
+     */
+    if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
+        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
+    else if (pThis->u32State != EVENTMULTI_STATE_NOT_SIGNALED)
+        rc = VERR_SEM_DESTROYED;
+
+    /*
+     * Release the mutex and return.
+     */
+    rcPosix = pthread_mutex_unlock(&pThis->Mutex);
+    if (RT_UNLIKELY(rcPosix))
+    {
+        AssertMsgFailed(("Failed to unlock event multi sem %p, rc=%d.\n", hEventMultiSem, rcPosix));
+        return RTErrConvertFromErrno(rcPosix);
+    }
+
+    return rc;
+}
+
+
+/**
+ * Handle polling (timeout already expired at the time of the call).
+ *
+ * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED.
+ * @param   pThis               The semaphore.
+ */
+DECLINLINE(int) rtSemEventMultiPosixWaitPoll(struct RTSEMEVENTMULTIINTERNAL *pThis)
+{
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    AssertMsgReturn(!rc, ("Failed to lock event multi sem %p, rc=%d.\n", pThis, rc), RTErrConvertFromErrno(rc));
+
+    uint32_t const u32State = pThis->u32State;
+
+    rc = pthread_mutex_unlock(&pThis->Mutex);
+    AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc)); NOREF(rc);
+
+    return u32State == EVENTMULTI_STATE_SIGNALED
+         ? VINF_SUCCESS
+         : u32State != EVENTMULTI_STATE_UNINITIALIZED
+         ? VERR_TIMEOUT
+         : VERR_SEM_DESTROYED;
+}
+
+
+
+/**
+ * Implements the indefinite wait.
+ *
+ * @returns See RTSemEventMultiWaitEx.
+ * @param   pThis               The semaphore.
+ * @param   fFlags              See RTSemEventMultiWaitEx.
+ * @param   pSrcPos             The source position, can be NULL.
+ */
+static int rtSemEventMultiPosixWaitIndefinite(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /* take mutex */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    AssertMsgReturn(!rc, ("Failed to lock event multi sem %p, rc=%d.\n", pThis, rc), RTErrConvertFromErrno(rc));
+    ASMAtomicIncU32(&pThis->cWaiters);
+
+    for (;;)
+    {
+        /* check state. */
+        uint32_t const u32State = pThis->u32State;
+        if (u32State != EVENTMULTI_STATE_NOT_SIGNALED)
+        {
+            ASMAtomicDecU32(&pThis->cWaiters);
+            rc = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc));
+            return u32State == EVENTMULTI_STATE_SIGNALED
+                 ? VINF_SUCCESS
+                 : VERR_SEM_DESTROYED;
+        }
+
+        /* wait */
+#ifdef RTSEMEVENTMULTI_STRICT
+        RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT_MULTI, true);
+            if (RT_FAILURE(rc))
+            {
+                ASMAtomicDecU32(&pThis->cWaiters);
+                pthread_mutex_unlock(&pThis->Mutex);
+                return rc;
+            }
+        }
+#else
+        RTTHREAD hThreadSelf = RTThreadSelf();
+        RT_NOREF_PV(pSrcPos);
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
+        /** @todo interruptible wait is not implementable... */ NOREF(fFlags);
+        rc = pthread_cond_wait(&pThis->Cond, &pThis->Mutex);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
+        if (RT_UNLIKELY(rc))
+        {
+            AssertMsgFailed(("Failed to wait on event multi sem %p, rc=%d.\n", pThis, rc));
+            ASMAtomicDecU32(&pThis->cWaiters);
+            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc2)); NOREF(rc2);
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+}
+
+
+/**
+ * Implements the timed wait.
+ *
+ * @returns See RTSemEventMultiWaitEx
+ * @param   pThis               The semaphore.
+ * @param   fFlags              See RTSemEventMultiWaitEx.
+ * @param   uTimeout            See RTSemEventMultiWaitEx.
+ * @param   pSrcPos             The source position, can be NULL.
+ */
+static int rtSemEventMultiPosixWaitTimed(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout,
+                                         PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Convert the timeout specification to absolute and relative deadlines,
+     * divierting polling and infinite waits to the appropriate workers.
+     */
+    struct timespec AbsDeadline         = { 0, 0 };
+    uint64_t const  cNsRelativeDeadline = rtSemPosixCalcDeadline(fFlags, uTimeout, pThis->fMonotonicClock, &AbsDeadline);
+    if (cNsRelativeDeadline == 0)
+        return rtSemEventMultiPosixWaitPoll(pThis);
+    if (cNsRelativeDeadline == UINT64_MAX)
+        return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);
+
+    /*
+     * To business!
+     */
+    /* take mutex */
+    int rc = pthread_mutex_lock(&pThis->Mutex);
+    AssertMsgReturn(rc == 0, ("rc=%d pThis=%p\n", rc, pThis), RTErrConvertFromErrno(rc)); NOREF(rc);
+    ASMAtomicIncU32(&pThis->cWaiters);
+
+    for (;;)
+    {
+        /* check state. */
+        uint32_t const u32State = pThis->u32State;
+        if (u32State != EVENTMULTI_STATE_NOT_SIGNALED)
+        {
+            ASMAtomicDecU32(&pThis->cWaiters);
+            rc = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc));
+            return u32State == EVENTMULTI_STATE_SIGNALED
+                 ? VINF_SUCCESS
+                 : VERR_SEM_DESTROYED;
+        }
+
+        /* wait */
+#ifdef RTSEMEVENTMULTI_STRICT
+        RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+        if (pThis->fEverHadSignallers)
+        {
+            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                       (uTimeout + RT_NS_1MS - 1)/ RT_NS_1MS, RTTHREADSTATE_EVENT_MULTI, true);
+            if (RT_FAILURE(rc))
+            {
+                ASMAtomicDecU32(&pThis->cWaiters);
+                pthread_mutex_unlock(&pThis->Mutex);
+                return rc;
+            }
+        }
+#else
+        RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
+        rc = pthread_cond_timedwait(&pThis->Cond, &pThis->Mutex, &AbsDeadline);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
+
+        /* According to SuS this function shall not return EINTR, but linux man page might have said differently at some point... */
+        if (    rc != 0
+            && (   rc != EINTR
+                || (fFlags & RTSEMWAIT_FLAGS_NORESUME)) )
+        {
+            AssertMsg(rc == ETIMEDOUT, ("Failed to wait on event multi sem %p, rc=%d.\n", pThis, rc));
+            ASMAtomicDecU32(&pThis->cWaiters);
+            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
+            AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc2)); NOREF(rc2);
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+}
+
+
+DECLINLINE(int) rtSemEventMultiPosixWait(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
+                                         PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    uint32_t u32 = pThis->u32State;
+    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);
+    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Optimize the case where the event is signalled.
+     */
+    if (ASMAtomicUoReadU32(&pThis->u32State) == EVENTMULTI_STATE_SIGNALED)
+    {
+        int rc = rtSemEventMultiPosixWaitPoll(pThis);
+        if (RT_LIKELY(rc != VERR_TIMEOUT))
+            return rc;
+    }
+
+    /*
+     * Indefinite or timed wait?
+     */
+    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
+        return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);
+    return rtSemEventMultiPosixWaitTimed(pThis, fFlags, uTimeout, pSrcPos);
+}
+
+
+#undef RTSemEventMultiWaitEx
+RTDECL(int)  RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+    return rtSemEventMultiPosixWait(hEventMultiSem, fFlags, uTimeout, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemEventMultiPosixWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+
+
+RTDECL(int)  RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
+                                        RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemEventMultiPosixWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+}
+
+
+RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENTMULTI_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    uint32_t u32 = pThis->u32State;
+    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/posix/semmutex-posix.cpp b/src/VBox/Runtime/r3/posix/semmutex-posix.cpp
new file mode 100644
index 00000000..f0df48ef
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/semmutex-posix.cpp
@@ -0,0 +1,467 @@
+/* $Id: semmutex-posix.cpp $ */
+/** @file
+ * IPRT - Mutex Semaphore, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloc.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/thread.h>
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Posix internal representation of a Mutex semaphore. */
+struct RTSEMMUTEXINTERNAL
+{
+    /** pthread mutex. */
+    pthread_mutex_t     Mutex;
+    /** The owner of the mutex. */
+    volatile pthread_t  Owner;
+    /** Nesting count. */
+    volatile uint32_t   cNesting;
+    /** Magic value (RTSEMMUTEX_MAGIC). */
+    uint32_t            u32Magic;
+#ifdef RTSEMMUTEX_STRICT
+    /** Lock validator record associated with this mutex. */
+    RTLOCKVALRECEXCL    ValidatorRec;
+#endif
+};
+
+#if defined(RT_OS_DARWIN) || defined(RT_OS_NETBSD)
+/**
+ * This function is a crude approximation of pthread_mutex_timedlock.
+ */
+int rtSemFallbackPthreadMutexTimedlock(pthread_mutex_t *mutex, RTMSINTERVAL cMillies)
+{
+    struct timespec ts;
+    int rc;
+
+    rc = pthread_mutex_trylock(mutex);
+    if (rc != EBUSY)
+        return rc;
+
+    ts.tv_sec = cMillies / 1000;
+    ts.tv_nsec = (cMillies % 1000) * 1000000;
+
+    while (ts.tv_sec > 0 || ts.tv_nsec > 0)
+    {
+        struct timespec delta, remaining;
+
+        if (ts.tv_sec > 0)
+        {
+            delta.tv_sec = 1;
+            delta.tv_nsec = 0;
+            ts.tv_sec--;
+        }
+        else
+        {
+            delta.tv_sec = 0;
+            delta.tv_nsec = ts.tv_nsec;
+            ts.tv_nsec = 0;
+        }
+
+        nanosleep(&delta, &remaining);
+
+        rc = pthread_mutex_trylock(mutex);
+        if (rc != EBUSY)
+            return rc;
+
+        if (RT_UNLIKELY(remaining.tv_nsec > 0 || remaining.tv_sec > 0))
+        {
+            ts.tv_sec += remaining.tv_sec;
+            ts.tv_nsec += remaining.tv_nsec;
+            if (ts.tv_nsec >= 1000000000)
+            {
+                ts.tv_nsec -= 1000000000;
+                ts.tv_sec++;
+            }
+        }
+    }
+
+    return ETIMEDOUT;
+}
+#endif
+
+
+#undef RTSemMutexCreate
+RTDECL(int)  RTSemMutexCreate(PRTSEMMUTEX phMutexSem)
+{
+    return RTSemMutexCreateEx(phMutexSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+}
+
+
+RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags,
+                               RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate semaphore handle.
+     */
+    int rc;
+    struct RTSEMMUTEXINTERNAL *pThis = (struct RTSEMMUTEXINTERNAL *)RTMemAlloc(sizeof(struct RTSEMMUTEXINTERNAL));
+    if (pThis)
+    {
+        /*
+         * Create the semaphore.
+         */
+        rc = pthread_mutex_init(&pThis->Mutex, NULL);
+        if (!rc)
+        {
+            pThis->Owner    = (pthread_t)-1;
+            pThis->cNesting = 0;
+            pThis->u32Magic = RTSEMMUTEX_MAGIC;
+#ifdef RTSEMMUTEX_STRICT
+            if (!pszNameFmt)
+            {
+                static uint32_t volatile s_iMutexAnon = 0;
+                RTLockValidatorRecExclInit(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                           !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL),
+                                           "RTSemMutex-%u", ASMAtomicIncU32(&s_iMutexAnon) - 1);
+            }
+            else
+            {
+                va_list va;
+                va_start(va, pszNameFmt);
+                RTLockValidatorRecExclInitV(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                            !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), pszNameFmt, va);
+                va_end(va);
+            }
+#else
+            RT_NOREF_PV(hClass); RT_NOREF_PV(uSubClass); RT_NOREF_PV(pszNameFmt);
+#endif
+
+            *phMutexSem = pThis;
+            return VINF_SUCCESS;
+        }
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSemMutexDestroy(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate input.
+     */
+    if (hMutexSem == NIL_RTSEMMUTEX)
+        return VINF_SUCCESS;
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Try destroy it.
+     */
+    int rc = pthread_mutex_destroy(&pThis->Mutex);
+    if (rc)
+    {
+        AssertMsgFailed(("Failed to destroy mutex sem %p, rc=%d.\n", hMutexSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    /*
+     * Free the memory and be gone.
+     */
+    ASMAtomicWriteU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD);
+    pThis->Owner    = (pthread_t)-1;
+    pThis->cNesting = UINT32_MAX;
+#ifdef RTSEMMUTEX_STRICT
+    RTLockValidatorRecExclDelete(&pThis->ValidatorRec);
+#endif
+    RTMemTmpFree(pThis);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass)
+{
+#ifdef RTSEMMUTEX_STRICT
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
+
+    return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass);
+#else
+    RT_NOREF_PV(hMutexSem); RT_NOREF_PV(uSubClass);
+    return RTLOCKVAL_SUB_CLASS_INVALID;
+#endif
+}
+
+
+DECL_FORCE_INLINE(int) rtSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Check if nested request.
+     */
+    pthread_t Self = pthread_self();
+    if (    pThis->Owner == Self
+        &&  pThis->cNesting > 0)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorRec, pSrcPos);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        ASMAtomicIncU32(&pThis->cNesting);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Lock it.
+     */
+    RTTHREAD hThreadSelf = NIL_RTTHREAD;
+    if (cMillies != 0)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        hThreadSelf = RTThreadSelfAutoAdopt();
+        int rc9 = RTLockValidatorRecExclCheckOrderAndBlocking(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true,
+                                                              cMillies, RTTHREADSTATE_MUTEX, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#else
+        hThreadSelf = RTThreadSelf();
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_MUTEX, true);
+        RT_NOREF_PV(pSrcPos);
+#endif
+    }
+
+    if (cMillies == RT_INDEFINITE_WAIT)
+    {
+        /* take mutex */
+        int rc = pthread_mutex_lock(&pThis->Mutex);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX);
+        if (rc)
+        {
+            AssertMsgFailed(("Failed to lock mutex sem %p, rc=%d.\n", hMutexSem, rc)); NOREF(rc);
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+    else
+    {
+        int rc;
+#if !defined(RT_OS_DARWIN) && !defined(RT_OS_NETBSD)
+        struct timespec     ts = {0,0};
+# if defined(RT_OS_HAIKU)
+        struct timeval      tv = {0,0};
+        gettimeofday(&tv, NULL);
+        ts.tv_sec = tv.tv_sec;
+        ts.tv_nsec = tv.tv_usec * 1000;
+# else
+        clock_gettime(CLOCK_REALTIME, &ts);
+# endif
+        if (cMillies != 0)
+        {
+            ts.tv_nsec += (cMillies % 1000) * 1000000;
+            ts.tv_sec  += cMillies / 1000;
+            if (ts.tv_nsec >= 1000000000)
+            {
+                ts.tv_nsec -= 1000000000;
+                ts.tv_sec++;
+            }
+        }
+
+        /* take mutex */
+        rc = pthread_mutex_timedlock(&pThis->Mutex, &ts);
+#else
+        /*
+         * When there's no pthread_mutex_timedlock() use a crude sleep
+         * and retry approximation.  Since the sleep interval is
+         * relative, we don't need to convert to the absolute time
+         * here only to convert back to relative in the fallback
+         * function.
+         */
+        rc = rtSemFallbackPthreadMutexTimedlock(&pThis->Mutex, cMillies);
+#endif
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX);
+        if (rc)
+        {
+            AssertMsg(rc == ETIMEDOUT, ("Failed to lock mutex sem %p, rc=%d.\n", hMutexSem, rc)); NOREF(rc);
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+
+    /*
+     * Set the owner and nesting.
+     */
+    pThis->Owner = Self;
+    ASMAtomicWriteU32(&pThis->cNesting, 1);
+#ifdef RTSEMMUTEX_STRICT
+    RTLockValidatorRecExclSetOwner(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true);
+#endif
+
+    return VINF_SUCCESS;
+}
+
+
+#undef RTSemMutexRequest
+RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMMUTEX_STRICT
+    return rtSemMutexRequest(hMutexSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, &SrcPos);
+}
+
+
+#undef RTSemMutexRequestNoResume
+RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+    /* (EINTR isn't returned by the wait functions we're using.) */
+#ifndef RTSEMMUTEX_STRICT
+    return rtSemMutexRequest(hMutexSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemMutexRequest(hMutexSem, cMillies, &SrcPos);
+}
+
+
+RTDECL(int)  RTSemMutexRelease(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMMUTEX_STRICT
+    int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorRec, pThis->cNesting == 1);
+    if (RT_FAILURE(rc9))
+        return rc9;
+#endif
+
+    /*
+     * Check if nested.
+     */
+    pthread_t Self = pthread_self();
+    if (RT_UNLIKELY(    pThis->Owner != Self
+                    ||  pThis->cNesting == 0))
+    {
+        AssertMsgFailed(("Not owner of mutex %p!! Self=%08x Owner=%08x cNesting=%d\n",
+                         pThis, Self, pThis->Owner, pThis->cNesting));
+        return VERR_NOT_OWNER;
+    }
+
+    /*
+     * If nested we'll just pop a nesting.
+     */
+    if (pThis->cNesting > 1)
+    {
+        ASMAtomicDecU32(&pThis->cNesting);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Clear the state. (cNesting == 1)
+     */
+    pThis->Owner = (pthread_t)-1;
+    ASMAtomicWriteU32(&pThis->cNesting, 0);
+
+    /*
+     * Unlock mutex semaphore.
+     */
+    int rc = pthread_mutex_unlock(&pThis->Mutex);
+    if (RT_UNLIKELY(rc))
+    {
+        AssertMsgFailed(("Failed to unlock mutex sem %p, rc=%d.\n", hMutexSem, rc)); NOREF(rc);
+        return RTErrConvertFromErrno(rc);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, false);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, false);
+
+    return pThis->Owner != (pthread_t)-1;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/semrw-posix.cpp b/src/VBox/Runtime/r3/posix/semrw-posix.cpp
new file mode 100644
index 00000000..ab657566
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/semrw-posix.cpp
@@ -0,0 +1,741 @@
+/* $Id: semrw-posix.cpp $ */
+/** @file
+ * IPRT - Read-Write Semaphore, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/thread.h>
+
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @todo move this to r3/posix/something.h. */
+#ifdef RT_OS_SOLARIS
+# define ATOMIC_GET_PTHREAD_T(ppvVar, pThread) ASMAtomicReadSize(ppvVar, pThread)
+# define ATOMIC_SET_PTHREAD_T(ppvVar, pThread) ASMAtomicWriteSize(ppvVar, pThread)
+#else
+AssertCompileSize(pthread_t, sizeof(void *));
+# define ATOMIC_GET_PTHREAD_T(ppvVar, pThread) do { *(pThread) = (pthread_t)ASMAtomicReadPtr((void * volatile *)ppvVar); } while (0)
+# define ATOMIC_SET_PTHREAD_T(ppvVar, pThread) ASMAtomicWritePtr((void * volatile *)ppvVar, (void *)pThread)
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Posix internal representation of a read-write semaphore. */
+struct RTSEMRWINTERNAL
+{
+    /** The usual magic. (RTSEMRW_MAGIC) */
+    uint32_t            u32Magic;
+    /** The number of readers.
+     * (For preventing screwing up the lock on linux). */
+    uint32_t volatile   cReaders;
+    /** Number of write recursions. */
+    uint32_t            cWrites;
+    /** Number of read recursions by the writer. */
+    uint32_t            cWriterReads;
+    /** The write owner of the lock. */
+    volatile pthread_t  Writer;
+    /** pthread rwlock. */
+    pthread_rwlock_t    RWLock;
+#ifdef RTSEMRW_STRICT
+    /** The validator record for the writer. */
+    RTLOCKVALRECEXCL    ValidatorWrite;
+    /** The validator record for the readers. */
+    RTLOCKVALRECSHRD    ValidatorRead;
+#endif
+};
+
+
+
+#undef RTSemRWCreate
+RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem)
+{
+    return RTSemRWCreateEx(phRWSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW");
+}
+
+
+RTDECL(int) RTSemRWCreateEx(PRTSEMRW phRWSem, uint32_t fFlags,
+                            RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMRW_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate handle.
+     */
+    int rc;
+    struct RTSEMRWINTERNAL *pThis = (struct RTSEMRWINTERNAL *)RTMemAlloc(sizeof(struct RTSEMRWINTERNAL));
+    if (pThis)
+    {
+        /*
+         * Create the rwlock.
+         */
+        rc = pthread_rwlock_init(&pThis->RWLock, NULL);
+        if (!rc)
+        {
+            pThis->u32Magic     = RTSEMRW_MAGIC;
+            pThis->cReaders     = 0;
+            pThis->cWrites      = 0;
+            pThis->cWriterReads = 0;
+            pThis->Writer       = (pthread_t)-1;
+#ifdef RTSEMRW_STRICT
+            bool const fLVEnabled = !(fFlags & RTSEMRW_FLAGS_NO_LOCK_VAL);
+            if (!pszNameFmt)
+            {
+                static uint32_t volatile s_iSemRWAnon = 0;
+                uint32_t i = ASMAtomicIncU32(&s_iSemRWAnon) - 1;
+                RTLockValidatorRecExclInit(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
+                                           fLVEnabled, "RTSemRW-%u", i);
+                RTLockValidatorRecSharedInit(&pThis->ValidatorRead, hClass, uSubClass, pThis,
+                                             false /*fSignaller*/, fLVEnabled, "RTSemRW-%u", i);
+            }
+            else
+            {
+                va_list va;
+                va_start(va, pszNameFmt);
+                RTLockValidatorRecExclInitV(&pThis->ValidatorWrite, hClass, uSubClass, pThis,
+                                            fLVEnabled, pszNameFmt, va);
+                va_end(va);
+                va_start(va, pszNameFmt);
+                RTLockValidatorRecSharedInitV(&pThis->ValidatorRead, hClass, uSubClass, pThis,
+                                              false /*fSignaller*/, fLVEnabled, pszNameFmt, va);
+                va_end(va);
+            }
+            RTLockValidatorRecMakeSiblings(&pThis->ValidatorWrite.Core, &pThis->ValidatorRead.Core);
+#else
+            RT_NOREF_PV(hClass); RT_NOREF_PV(uSubClass); RT_NOREF_PV(pszNameFmt);
+#endif
+            *phRWSem = pThis;
+            return VINF_SUCCESS;
+        }
+
+        rc = RTErrConvertFromErrno(rc);
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input, nil handle is fine.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    if (pThis == NIL_RTSEMRW)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+    Assert(pThis->Writer == (pthread_t)-1);
+    Assert(!pThis->cReaders);
+    Assert(!pThis->cWrites);
+    Assert(!pThis->cWriterReads);
+
+    /*
+     * Try destroy it.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMRW_MAGIC, RTSEMRW_MAGIC), VERR_INVALID_HANDLE);
+    int rc = pthread_rwlock_destroy(&pThis->RWLock);
+    if (!rc)
+    {
+#ifdef RTSEMRW_STRICT
+        RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
+        RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
+#endif
+        RTMemFree(pThis);
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        ASMAtomicWriteU32(&pThis->u32Magic, RTSEMRW_MAGIC);
+        AssertMsgFailed(("Failed to destroy read-write sem %p, rc=%d.\n", hRWSem, rc));
+        rc = RTErrConvertFromErrno(rc);
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTSemRWSetSubClass(RTSEMRW hRWSem, uint32_t uSubClass)
+{
+#ifdef RTSEMRW_STRICT
+    /*
+     * Validate handle.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
+    AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
+
+    RTLockValidatorRecSharedSetSubClass(&pThis->ValidatorRead, uSubClass);
+    return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorWrite, uSubClass);
+#else
+    RT_NOREF_PV(hRWSem); RT_NOREF_PV(uSubClass);
+    return RTLOCKVAL_SUB_CLASS_INVALID;
+#endif
+}
+
+
+DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+
+    /*
+     * Check if it's the writer (implement write+read recursion).
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    if (Writer == Self)
+    {
+#ifdef RTSEMRW_STRICT
+        int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        Assert(pThis->cWriterReads < INT32_MAX);
+        pThis->cWriterReads++;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Try lock it.
+     */
+    RTTHREAD hThreadSelf = NIL_RTTHREAD;
+    if (cMillies > 0)
+    {
+#ifdef RTSEMRW_STRICT
+        hThreadSelf = RTThreadSelfAutoAdopt();
+        int rc9 = RTLockValidatorRecSharedCheckOrderAndBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
+                                                                cMillies, RTTHREADSTATE_RW_READ, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#else
+        hThreadSelf = RTThreadSelf();
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, true);
+        RT_NOREF_PV(pSrcPos);
+#endif
+    }
+
+    if (cMillies == RT_INDEFINITE_WAIT)
+    {
+        /* take rwlock */
+        int rc = pthread_rwlock_rdlock(&pThis->RWLock);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
+        if (rc)
+        {
+            AssertMsgFailed(("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+    else
+    {
+#ifdef RT_OS_DARWIN
+        AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
+        return VERR_NOT_IMPLEMENTED;
+
+#else /* !RT_OS_DARWIN */
+        /*
+         * Get current time and calc end of wait time.
+         */
+        struct timespec     ts = {0,0};
+        clock_gettime(CLOCK_REALTIME, &ts);
+        if (cMillies != 0)
+        {
+            ts.tv_nsec += (cMillies % 1000) * 1000000;
+            ts.tv_sec  += cMillies / 1000;
+            if (ts.tv_nsec >= 1000000000)
+            {
+                ts.tv_nsec -= 1000000000;
+                ts.tv_sec++;
+            }
+        }
+
+        /* take rwlock */
+        int rc = pthread_rwlock_timedrdlock(&pThis->RWLock, &ts);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
+        if (rc)
+        {
+            AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
+            return RTErrConvertFromErrno(rc);
+        }
+#endif /* !RT_OS_DARWIN */
+    }
+
+    ASMAtomicIncU32(&pThis->cReaders);
+#ifdef RTSEMRW_STRICT
+    RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
+#endif
+    return VINF_SUCCESS;
+}
+
+
+#undef RTSemRWRequestRead
+RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+    return rtSemRWRequestRead(hRWSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
+}
+
+
+#undef RTSemRWRequestReadNoResume
+RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+    /* EINTR isn't returned by the wait functions we're using. */
+#ifndef RTSEMRW_STRICT
+    return rtSemRWRequestRead(hRWSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemRWRequestRead(hRWSem, cMillies, &SrcPos);
+}
+
+
+RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+
+    /*
+     * Check if it's the writer.
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    if (Writer == Self)
+    {
+        AssertMsgReturn(pThis->cWriterReads > 0, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
+#ifdef RTSEMRW_STRICT
+        int rc9 = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        pThis->cWriterReads--;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Try unlock it.
+     */
+#ifdef RTSEMRW_STRICT
+    int rc9 = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, RTThreadSelf());
+    if (RT_FAILURE(rc9))
+        return rc9;
+#endif
+#ifdef RT_OS_LINUX /* glibc (at least 2.8) may screw up when unlocking a lock we don't own. */
+    if (ASMAtomicReadU32(&pThis->cReaders) == 0)
+    {
+        AssertMsgFailed(("Not owner of %p\n", pThis));
+        return VERR_NOT_OWNER;
+    }
+#endif
+    ASMAtomicDecU32(&pThis->cReaders);
+    int rc = pthread_rwlock_unlock(&pThis->RWLock);
+    if (rc)
+    {
+        ASMAtomicIncU32(&pThis->cReaders);
+        AssertMsgFailed(("Failed read unlock read-write sem %p, rc=%d.\n", hRWSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+    return VINF_SUCCESS;
+}
+
+
+DECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+
+    /*
+     * Recursion?
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    if (Writer == Self)
+    {
+#ifdef RTSEMRW_STRICT
+        int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorWrite, pSrcPos);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        Assert(pThis->cWrites < INT32_MAX);
+        pThis->cWrites++;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Try lock it.
+     */
+    RTTHREAD hThreadSelf = NIL_RTTHREAD;
+    if (cMillies)
+    {
+#ifdef RTSEMRW_STRICT
+        hThreadSelf = RTThreadSelfAutoAdopt();
+        int rc9 = RTLockValidatorRecExclCheckOrderAndBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
+                                                              cMillies, RTTHREADSTATE_RW_WRITE, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#else
+        hThreadSelf = RTThreadSelf();
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, true);
+        RT_NOREF_PV(pSrcPos);
+#endif
+    }
+
+    if (cMillies == RT_INDEFINITE_WAIT)
+    {
+        /* take rwlock */
+        int rc = pthread_rwlock_wrlock(&pThis->RWLock);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
+        if (rc)
+        {
+            AssertMsgFailed(("Failed write lock read-write sem %p, rc=%d.\n", hRWSem, rc));
+            return RTErrConvertFromErrno(rc);
+        }
+    }
+    else
+    {
+#ifdef RT_OS_DARWIN
+        AssertMsgFailed(("Not implemented on Darwin yet because of incomplete pthreads API."));
+        return VERR_NOT_IMPLEMENTED;
+#else /* !RT_OS_DARWIN */
+        /*
+         * Get current time and calc end of wait time.
+         */
+        struct timespec     ts = {0,0};
+        clock_gettime(CLOCK_REALTIME, &ts);
+        if (cMillies != 0)
+        {
+            ts.tv_nsec += (cMillies % 1000) * 1000000;
+            ts.tv_sec  += cMillies / 1000;
+            if (ts.tv_nsec >= 1000000000)
+            {
+                ts.tv_nsec -= 1000000000;
+                ts.tv_sec++;
+            }
+        }
+
+        /* take rwlock */
+        int rc = pthread_rwlock_timedwrlock(&pThis->RWLock, &ts);
+        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
+        if (rc)
+        {
+            AssertMsg(rc == ETIMEDOUT, ("Failed read lock read-write sem %p, rc=%d.\n", hRWSem, rc));
+            return RTErrConvertFromErrno(rc);
+        }
+#endif /* !RT_OS_DARWIN */
+    }
+
+    ATOMIC_SET_PTHREAD_T(&pThis->Writer, Self);
+    pThis->cWrites = 1;
+    Assert(!pThis->cReaders);
+#ifdef RTSEMRW_STRICT
+    RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
+#endif
+    return VINF_SUCCESS;
+}
+
+
+#undef RTSemRWRequestWrite
+RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+    return rtSemRWRequestWrite(hRWSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
+}
+
+
+#undef RTSemRWRequestWriteNoResume
+RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+    /* EINTR isn't returned by the wait functions we're using. */
+#ifndef RTSEMRW_STRICT
+    return rtSemRWRequestWrite(hRWSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    /* EINTR isn't returned by the wait functions we're using. */
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemRWRequestWrite(hRWSem, cMillies, &SrcPos);
+}
+
+
+RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    VERR_INVALID_HANDLE);
+
+    /*
+     * Verify ownership and implement recursion.
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    AssertMsgReturn(Writer == Self, ("pThis=%p\n", pThis), VERR_NOT_OWNER);
+    AssertReturn(pThis->cWriterReads == 0 || pThis->cWrites > 1, VERR_WRONG_ORDER);
+
+    if (pThis->cWrites > 1)
+    {
+#ifdef RTSEMRW_STRICT
+        int rc9 = RTLockValidatorRecExclUnwind(&pThis->ValidatorWrite);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        pThis->cWrites--;
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Try unlock it.
+     */
+#ifdef RTSEMRW_STRICT
+    int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, true);
+    if (RT_FAILURE(rc9))
+        return rc9;
+#endif
+
+    pThis->cWrites--;
+    ATOMIC_SET_PTHREAD_T(&pThis->Writer, (pthread_t)-1);
+    int rc = pthread_rwlock_unlock(&pThis->RWLock);
+    if (rc)
+    {
+        AssertMsgFailed(("Failed write unlock read-write sem %p, rc=%d.\n", hRWSem, rc));
+        return RTErrConvertFromErrno(rc);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, false);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    false);
+
+    /*
+     * Check ownership.
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    return Writer == Self;
+}
+
+
+RTDECL(bool)  RTSemRWIsReadOwner(RTSEMRW hRWSem, bool fWannaHear)
+{
+    /*
+     * Validate handle.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, false);
+    AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
+
+    /*
+     * Check write ownership.  The writer is also a valid reader.
+     */
+    pthread_t Self = pthread_self();
+    pthread_t Writer;
+    ATOMIC_GET_PTHREAD_T(&pThis->Writer, &Writer);
+    if (Writer == Self)
+        return true;
+    if (Writer != (pthread_t)-1)
+        return false;
+
+    /*
+     * If there are no readers, we cannot be one of them, can we?
+     */
+    if (ASMAtomicReadU32(&pThis->cReaders) == 0)
+        return false;
+
+#ifdef RTSEMRW_STRICT
+    /*
+     * Ask the lock validator.
+     */
+    NOREF(fWannaHear);
+    return RTLockValidatorRecSharedIsOwner(&pThis->ValidatorRead, NIL_RTTHREAD);
+#else
+    /*
+     * Just tell the caller what he want to hear.
+     */
+    return fWannaHear;
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWIsReadOwner);
+
+
+RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, 0);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    0);
+
+    /*
+     * Return the requested data.
+     */
+    return pThis->cWrites;
+}
+
+
+RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, 0);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    0);
+
+    /*
+     * Return the requested data.
+     */
+    return pThis->cWriterReads;
+}
+
+
+RTDECL(uint32_t) RTSemRWGetReadCount(RTSEMRW hRWSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMRWINTERNAL *pThis = hRWSem;
+    AssertPtrReturn(pThis, 0);
+    AssertMsgReturn(pThis->u32Magic == RTSEMRW_MAGIC,
+                    ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic),
+                    0);
+
+    /*
+     * Return the requested data.
+     */
+    return pThis->cReaders;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/semwait.h b/src/VBox/Runtime/r3/posix/semwait.h
new file mode 100644
index 00000000..ade8c4a7
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/semwait.h
@@ -0,0 +1,162 @@
+/* $Id: semwait.h $ */
+/** @file
+ * IPRT - Common semaphore wait code.
+ */
+
+/*
+ * Copyright (C) 2021-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_posix_semwait_h
+#define IPRT_INCLUDED_SRC_r3_posix_semwait_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+
+/** @def IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
+ * Set if the platform implements pthread_condattr_setclock().
+ * Enables the use of the monotonic clock for waiting on condition variables. */
+#ifndef IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
+/* Linux detection */
+# if defined(RT_OS_LINUX) && defined(__USE_XOPEN2K)
+#  include <features.h>
+#  if __GLIBC_PREREQ(2,6) /** @todo figure the exact version where this was added */
+#   define IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
+#  endif
+# endif
+/** @todo check other platforms */
+#endif
+
+
+/**
+ * Converts a extended wait timeout specification to an absolute timespec and a
+ * relative nanosecond count.
+ *
+ * @note    This does not check for RTSEMWAIT_FLAGS_INDEFINITE, caller should've
+ *          done that already.
+ *
+ * @returns The relative wait in nanoseconds.  0 for a poll call, UINT64_MAX for
+ *          an effectively indefinite wait.
+ * @param   fFlags          RTSEMWAIT_FLAGS_XXX.
+ * @param   fMonotonicClock Whether the timeout is in monotonic (true) or real
+ *                          (false) time.
+ * @param   uTimeout        The timeout.
+ * @param   pAbsDeadline    Where to return the absolute deadline.
+ */
+DECLINLINE(uint64_t) rtSemPosixCalcDeadline(uint32_t fFlags, uint64_t uTimeout, bool fMonotonicClock,
+                                            struct timespec *pAbsDeadline)
+{
+    Assert(!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE));
+
+    /*
+     * Convert uTimeout to a relative value in nanoseconds.
+     */
+    if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
+    {
+        if (uTimeout < UINT64_MAX / RT_NS_1MS)
+            uTimeout = uTimeout * RT_NS_1MS;
+        else
+            return UINT64_MAX;
+    }
+    else if (uTimeout == UINT64_MAX) /* unofficial way of indicating an indefinite wait */
+        return UINT64_MAX;
+
+    /*
+     * Make uTimeout relative and check for polling (zero timeout) calls.
+     */
+    uint64_t uAbsTimeout = uTimeout;
+    if (fFlags & RTSEMWAIT_FLAGS_ABSOLUTE)
+    {
+        uint64_t const u64Now = RTTimeSystemNanoTS();
+        if (uTimeout > u64Now)
+            uTimeout -= u64Now;
+        else
+            return 0;
+    }
+    else if (uTimeout == 0)
+        return 0;
+
+    /*
+     * Calculate the deadline according to the clock we're using.
+     */
+    if (!fMonotonicClock)
+    {
+#if defined(RT_OS_DARWIN) || defined(RT_OS_HAIKU)
+        struct timeval  tv = {0,0};
+        gettimeofday(&tv, NULL);
+        pAbsDeadline->tv_sec  = tv.tv_sec;
+        pAbsDeadline->tv_nsec = tv.tv_usec * 1000;
+#else
+        clock_gettime(CLOCK_REALTIME, pAbsDeadline);
+#endif
+        struct timespec TsAdd;
+        TsAdd.tv_nsec = uTimeout % RT_NS_1SEC;
+        TsAdd.tv_sec  = uTimeout / RT_NS_1SEC;
+
+        /* Check for 32-bit tv_sec overflows: */
+        if (   sizeof(pAbsDeadline->tv_sec) < sizeof(uint64_t)
+            && (   uTimeout >= (uint64_t)RT_NS_1SEC * UINT32_MAX
+                || (uint64_t)pAbsDeadline->tv_sec + pAbsDeadline->tv_sec >= UINT32_MAX) )
+            return UINT64_MAX;
+
+        pAbsDeadline->tv_sec  += TsAdd.tv_sec;
+        pAbsDeadline->tv_nsec += TsAdd.tv_nsec;
+        if ((uint32_t)pAbsDeadline->tv_nsec >= RT_NS_1SEC)
+        {
+            pAbsDeadline->tv_nsec -= RT_NS_1SEC;
+            pAbsDeadline->tv_sec++;
+        }
+    }
+    else
+    {
+        /* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
+        if (fFlags & RTSEMWAIT_FLAGS_RELATIVE)
+        {
+            uint64_t const nsNow = RTTimeSystemNanoTS();
+            uAbsTimeout += nsNow;
+            if (uAbsTimeout < nsNow)
+                return UINT64_MAX;
+        }
+
+        /* Check for 32-bit tv_sec overflows: */
+        if (   sizeof(pAbsDeadline->tv_sec) < sizeof(uint64_t)
+            && uAbsTimeout >= (uint64_t)RT_NS_1SEC * UINT32_MAX)
+            return UINT64_MAX;
+
+        pAbsDeadline->tv_nsec = uAbsTimeout % RT_NS_1SEC;
+        pAbsDeadline->tv_sec  = uAbsTimeout / RT_NS_1SEC;
+    }
+
+    return uTimeout;
+}
+
+#endif /* !IPRT_INCLUDED_SRC_r3_posix_semwait_h */
+
diff --git a/src/VBox/Runtime/r3/posix/serialport-posix.cpp b/src/VBox/Runtime/r3/posix/serialport-posix.cpp
new file mode 100644
index 00000000..0afbb676
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/serialport-posix.cpp
@@ -0,0 +1,1269 @@
+/* $Id: serialport-posix.cpp $ */
+/** @file
+ * IPRT - Serial Port API, POSIX Implementation.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/serialport.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+
+#include <errno.h>
+#ifdef RT_OS_SOLARIS
+# include <sys/termios.h>
+#else
+# include <termios.h>
+#endif
+#include <sys/types.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef RT_OS_DARWIN
+# include <sys/poll.h>
+#else
+# include <sys/poll.h>
+#endif
+#include <sys/ioctl.h>
+#include <pthread.h>
+
+#ifdef RT_OS_LINUX
+/*
+ * TIOCM_LOOP is not defined in the above header files for some reason but in asm/termios.h.
+ * But inclusion of this file however leads to compilation errors because of redefinition of some
+ * structs. That's why it is defined here until a better solution is found.
+ */
+# ifndef TIOCM_LOOP
+#  define TIOCM_LOOP 0x8000
+# endif
+/* For linux custom baudrate code we also need serial_struct */
+# include <linux/serial.h>
+#endif /* linux */
+
+/** Define fallback if not supported. */
+#if !defined(CMSPAR)
+# define CMSPAR 0
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Internal serial port state.
+ */
+typedef struct RTSERIALPORTINTERNAL
+{
+    /** Magic value (RTSERIALPORT_MAGIC). */
+    uint32_t            u32Magic;
+    /** Flags given while opening the serial port. */
+    uint32_t            fOpenFlags;
+    /** The file descriptor of the serial port. */
+    int                 iFd;
+    /** The status line monitor thread if enabled. */
+    RTTHREAD            hMonThrd;
+    /** Flag whether the monitoring thread should shutdown. */
+    volatile bool       fMonThrdShutdown;
+    /** Reading end of wakeup pipe. */
+    int                 iFdPipeR;
+    /** Writing end of wakeup pipe. */
+    int                 iFdPipeW;
+    /** Event pending mask. */
+    volatile uint32_t   fEvtsPending;
+    /** Flag whether we are in blocking or non blocking mode. */
+    bool                fBlocking;
+    /** The current active config (we assume no one changes this behind our back). */
+    struct termios      PortCfg;
+    /** Flag whether a custom baud rate was chosen (for hosts supporting this.). */
+    bool                fBaudrateCust;
+    /** The custom baud rate. */
+    uint32_t            uBaudRateCust;
+} RTSERIALPORTINTERNAL;
+/** Pointer to the internal serial port state. */
+typedef RTSERIALPORTINTERNAL *PRTSERIALPORTINTERNAL;
+
+
+/**
+ * Baud rate conversion table descriptor.
+ */
+typedef struct RTSERIALPORTBRATECONVDESC
+{
+    /** The platform independent baud rate used by the RTSerialPort* API. */
+    uint32_t            uBaudRateCfg;
+    /** The speed identifier used in the termios structure. */
+    speed_t             iSpeedTermios;
+} RTSERIALPORTBRATECONVDESC;
+/** Pointer to a baud rate converions table descriptor. */
+typedef RTSERIALPORTBRATECONVDESC *PRTSERIALPORTBRATECONVDESC;
+/** Pointer to a const baud rate conversion table descriptor. */
+typedef const RTSERIALPORTBRATECONVDESC *PCRTSERIALPORTBRATECONVDESC;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+
+/** The event poller was woken up due to an external interrupt. */
+#define RTSERIALPORT_WAKEUP_PIPE_REASON_INTERRUPT               0x0
+/** The event poller was woken up due to a change in the monitored status lines. */
+#define RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_CHANGED        0x1
+/** The monitor thread encoutnered repeating errors querying the status lines and terminated. */
+#define RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_MONITOR_FAILED 0x2
+
+
+/*********************************************************************************************************************************
+*   Global variables                                                                                                             *
+*********************************************************************************************************************************/
+
+/** The baud rate conversion table. */
+static const RTSERIALPORTBRATECONVDESC s_rtSerialPortBaudrateConv[] =
+{
+    { 50,     B50     },
+    { 75,     B75     },
+    { 110,    B110    },
+    { 134,    B134    },
+    { 150,    B150    },
+    { 200,    B200    },
+    { 300,    B300    },
+    { 600,    B600    },
+    { 1200,   B1200   },
+    { 1800,   B1800   },
+    { 2400,   B2400   },
+    { 4800,   B4800   },
+    { 9600,   B9600   },
+    { 19200,  B19200  },
+    { 38400,  B38400  },
+    { 57600,  B57600  },
+    { 115200, B115200 }
+};
+
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Converts the given termios speed identifier to the baud rate used in the API.
+ *
+ * @returns Baud rate or 0 if not a standard baud rate
+ */
+DECLINLINE(uint32_t) rtSerialPortGetBaudrateFromTermiosSpeed(speed_t enmSpeed)
+{
+    for (unsigned i = 0; i < RT_ELEMENTS(s_rtSerialPortBaudrateConv); i++)
+    {
+        if (s_rtSerialPortBaudrateConv[i].iSpeedTermios == enmSpeed)
+            return s_rtSerialPortBaudrateConv[i].uBaudRateCfg;
+    }
+
+    return 0;
+}
+
+
+/**
+ * Converts the given baud rate to proper termios speed identifier.
+ *
+ * @returns Speed identifier if available or B0 if no matching speed for the baud rate
+ *          could be found.
+ * @param   uBaudRate               The baud rate to convert.
+ * @param   pfBaudrateCust          Where to store the flag whether a custom baudrate was selected.
+ */
+DECLINLINE(speed_t) rtSerialPortGetTermiosSpeedFromBaudrate(uint32_t uBaudRate, bool *pfBaudrateCust)
+{
+    *pfBaudrateCust = false;
+
+    for (unsigned i = 0; i < RT_ELEMENTS(s_rtSerialPortBaudrateConv); i++)
+    {
+        if (s_rtSerialPortBaudrateConv[i].uBaudRateCfg == uBaudRate)
+            return s_rtSerialPortBaudrateConv[i].iSpeedTermios;
+    }
+
+#ifdef RT_OS_LINUX
+    *pfBaudrateCust = true;
+    return B38400;
+#else
+    return B0;
+#endif
+}
+
+
+/**
+ * Tries to set the default config on the given serial port.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ */
+static int rtSerialPortSetDefaultCfg(PRTSERIALPORTINTERNAL pThis)
+{
+    pThis->fBaudrateCust = false;
+    pThis->uBaudRateCust = 0;
+    pThis->PortCfg.c_iflag = INPCK; /* Input parity checking. */
+    cfsetispeed(&pThis->PortCfg, B9600);
+    cfsetospeed(&pThis->PortCfg, B9600);
+    pThis->PortCfg.c_cflag |= CS8 | CLOCAL; /* 8 data bits, ignore modem control lines. */
+    if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_READ)
+        pThis->PortCfg.c_cflag |= CREAD;   /* Enable receiver. */
+
+    /* Set to raw input mode. */
+    pThis->PortCfg.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHONL | ECHOK | ISIG | IEXTEN);
+    pThis->PortCfg.c_cc[VMIN]  = 0; /* Achieve non-blocking behavior. */
+    pThis->PortCfg.c_cc[VTIME] = 0;
+
+    int rc = VINF_SUCCESS;
+    int rcPsx = tcflush(pThis->iFd, TCIOFLUSH);
+    if (!rcPsx)
+    {
+        rcPsx = tcsetattr(pThis->iFd, TCSANOW, &pThis->PortCfg);
+        if (rcPsx == -1)
+            rc = RTErrConvertFromErrno(errno);
+
+        if (RT_SUCCESS(rc))
+        {
+#ifdef RT_OS_LINUX
+            if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_ENABLE_LOOPBACK)
+            {
+                int fTiocmSet = TIOCM_LOOP;
+                rcPsx = ioctl(pThis->iFd, TIOCMBIS, &fTiocmSet);
+                if (rcPsx == -1)
+                    rc = RTErrConvertFromErrno(errno);
+            }
+            else
+            {
+                /* Make sure it is clear. */
+                int fTiocmClear = TIOCM_LOOP;
+                rcPsx = ioctl(pThis->iFd, TIOCMBIC, &fTiocmClear);
+                if (rcPsx == -1 && errno != EINVAL) /* Pseudo terminals don't support loopback mode so ignore an error here. */
+                    rc = RTErrConvertFromErrno(errno);
+            }
+#else
+            if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_ENABLE_LOOPBACK)
+                return VERR_NOT_SUPPORTED;
+#endif
+        }
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+
+/**
+ * Converts the given serial port config to the appropriate termios counterpart.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   pCfg                    Pointer to the serial port config descriptor.
+ * @param   pTermios                Pointer to the termios structure to fill.
+ * @param   pfBaudrateCust          Where to store the flag whether a custom baudrate was selected.
+ * @param   pErrInfo                Additional error to be set when the conversion fails.
+ */
+static int rtSerialPortCfg2Termios(PRTSERIALPORTINTERNAL pThis, PCRTSERIALPORTCFG pCfg, struct termios *pTermios,
+                                   bool *pfBaudrateCust, PRTERRINFO pErrInfo)
+{
+    RT_NOREF(pErrInfo); /** @todo Make use of the error info. */
+    speed_t enmSpeed = rtSerialPortGetTermiosSpeedFromBaudrate(pCfg->uBaudRate, pfBaudrateCust);
+    if (enmSpeed != B0)
+    {
+        tcflag_t const fCFlagMask = (CS5 | CS6 | CS7 | CS8 | CSTOPB | PARENB | PARODD | CMSPAR);
+        tcflag_t fCFlagNew = CLOCAL;
+
+        switch (pCfg->enmDataBitCount)
+        {
+            case RTSERIALPORTDATABITS_5BITS:
+                fCFlagNew |= CS5;
+                break;
+            case RTSERIALPORTDATABITS_6BITS:
+                fCFlagNew |= CS6;
+                break;
+            case RTSERIALPORTDATABITS_7BITS:
+                fCFlagNew |= CS7;
+                break;
+            case RTSERIALPORTDATABITS_8BITS:
+                fCFlagNew |= CS8;
+                break;
+            default:
+                AssertFailed();
+                return VERR_INVALID_PARAMETER;
+        }
+
+        switch (pCfg->enmParity)
+        {
+            case RTSERIALPORTPARITY_NONE:
+                break;
+            case RTSERIALPORTPARITY_EVEN:
+                fCFlagNew |= PARENB;
+                break;
+            case RTSERIALPORTPARITY_ODD:
+                fCFlagNew |= PARENB | PARODD;
+                break;
+#if CMSPAR != 0
+            case RTSERIALPORTPARITY_MARK:
+                fCFlagNew |= PARENB | CMSPAR | PARODD;
+                break;
+            case RTSERIALPORTPARITY_SPACE:
+                fCFlagNew |= PARENB | CMSPAR;
+                break;
+#else
+            case RTSERIALPORTPARITY_MARK:
+            case RTSERIALPORTPARITY_SPACE:
+                return VERR_NOT_SUPPORTED;
+#endif
+            default:
+                AssertFailed();
+                return VERR_INVALID_PARAMETER;
+        }
+
+        switch (pCfg->enmStopBitCount)
+        {
+            case RTSERIALPORTSTOPBITS_ONE:
+                break;
+            case RTSERIALPORTSTOPBITS_ONEPOINTFIVE:
+                if (pCfg->enmDataBitCount == RTSERIALPORTDATABITS_5BITS)
+                    fCFlagNew |= CSTOPB;
+                else
+                    return VERR_NOT_SUPPORTED;
+                break;
+            case RTSERIALPORTSTOPBITS_TWO:
+                if (pCfg->enmDataBitCount != RTSERIALPORTDATABITS_5BITS)
+                    fCFlagNew |= CSTOPB;
+                else
+                    return VERR_NOT_SUPPORTED;
+                break;
+            default:
+                AssertFailed();
+                return VERR_INVALID_PARAMETER;
+        }
+
+        /* Assign new flags. */
+        if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_READ)
+            pTermios->c_cflag |= CREAD;   /* Enable receiver. */
+        pTermios->c_cflag = (pTermios->c_cflag & ~fCFlagMask) | fCFlagNew;
+        pTermios->c_lflag &= ~(ICANON | ECHO | ECHOE | ECHONL | ECHOK | ISIG | IEXTEN);
+        pTermios->c_iflag = INPCK; /* Input parity checking. */
+        pTermios->c_cc[VMIN]  = 0; /* Achieve non-blocking behavior. */
+        pTermios->c_cc[VTIME] = 0;
+        cfsetispeed(pTermios, enmSpeed);
+        cfsetospeed(pTermios, enmSpeed);
+    }
+    else
+        return VERR_SERIALPORT_INVALID_BAUDRATE;
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Converts the given termios structure to an appropriate serial port config.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   pTermios                The termios structure to convert.
+ * @param   pCfg                    The serial port config to fill in.
+ */
+static int rtSerialPortTermios2Cfg(PRTSERIALPORTINTERNAL pThis, struct termios *pTermios, PRTSERIALPORTCFG pCfg)
+{
+    int rc = VINF_SUCCESS;
+    bool f5DataBits = false;
+    speed_t enmSpeedIn = cfgetispeed(pTermios);
+    Assert(enmSpeedIn == cfgetospeed(pTermios)); /* Should always be the same. */
+
+    if (!pThis->fBaudrateCust)
+    {
+        pCfg->uBaudRate = rtSerialPortGetBaudrateFromTermiosSpeed(enmSpeedIn);
+        if (!pCfg->uBaudRate)
+            rc = VERR_SERIALPORT_INVALID_BAUDRATE;
+    }
+    else
+        pCfg->uBaudRate = pThis->uBaudRateCust;
+
+    switch (pTermios->c_cflag & CSIZE)
+    {
+        case CS5:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_5BITS;
+            f5DataBits = true;
+            break;
+        case CS6:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_6BITS;
+            break;
+        case CS7:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_7BITS;
+            break;
+        case CS8:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_8BITS;
+            break;
+        default:
+            AssertFailed(); /* Should not happen. */
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_INVALID;
+            rc = RT_FAILURE(rc) ? rc : VERR_INVALID_PARAMETER;
+    }
+
+    /* Convert parity. */
+    if (pTermios->c_cflag & PARENB)
+    {
+        /*
+         * CMSPAR is not supported on all systems, especially OS X. As configuring
+         * mark/space parity there is not supported and we start from a known config
+         * when opening the serial port it is not required to check for this here.
+         */
+#if CMSPAR == 0
+        bool fCmsParSet = RT_BOOL(pTermios->c_cflag & CMSPAR);
+#else
+        bool fCmsParSet = false;
+#endif
+        if (pTermios->c_cflag & PARODD)
+            pCfg->enmParity = fCmsParSet ? RTSERIALPORTPARITY_MARK : RTSERIALPORTPARITY_ODD;
+        else
+            pCfg->enmParity = fCmsParSet ? RTSERIALPORTPARITY_SPACE: RTSERIALPORTPARITY_EVEN;
+    }
+    else
+        pCfg->enmParity = RTSERIALPORTPARITY_NONE;
+
+    /*
+     * 1.5 stop bits are used with a data count of 5 bits when a UART derived from the 8250
+     * is used.
+     */
+    if (pTermios->c_cflag & CSTOPB)
+        pCfg->enmStopBitCount = f5DataBits ? RTSERIALPORTSTOPBITS_ONEPOINTFIVE : RTSERIALPORTSTOPBITS_TWO;
+    else
+        pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_ONE;
+
+    return rc;
+}
+
+
+/**
+ * Wakes up any thread polling for a serial port event with the given reason.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   bWakeupReason           The wakeup reason to pass to the event poller.
+ */
+DECLINLINE(int) rtSerialPortWakeupEvtPoller(PRTSERIALPORTINTERNAL pThis, uint8_t bWakeupReason)
+{
+    int rcPsx = write(pThis->iFdPipeW, &bWakeupReason, 1);
+    if (rcPsx != 1)
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * The status line monitor thread worker.
+ *
+ * @returns IPRT status code.
+ * @param   ThreadSelf  Thread handle to this thread.
+ * @param   pvUser      User argument.
+ */
+static DECLCALLBACK(int) rtSerialPortStsLineMonitorThrd(RTTHREAD hThreadSelf, void *pvUser)
+{
+    RT_NOREF(hThreadSelf);
+    PRTSERIALPORTINTERNAL pThis = (PRTSERIALPORTINTERNAL)pvUser;
+    unsigned long const fStsLinesChk = TIOCM_CAR | TIOCM_RNG | TIOCM_DSR | TIOCM_CTS;
+    int rc = VINF_SUCCESS;
+    uint32_t fStsLinesOld = 0;
+    uint32_t cStsLineGetErrors = 0;
+#ifdef RT_OS_LINUX
+    bool fPoll = false;
+#endif
+
+    RTThreadUserSignal(hThreadSelf);
+
+    int rcPsx = ioctl(pThis->iFd, TIOCMGET, &fStsLinesOld);
+    if (rcPsx == -1)
+    {
+        ASMAtomicXchgBool(&pThis->fMonThrdShutdown, true);
+        return RTErrConvertFromErrno(errno);
+    }
+
+    while (   !pThis->fMonThrdShutdown
+           && RT_SUCCESS(rc))
+    {
+# ifdef RT_OS_LINUX
+        /*
+         * Wait for status line change.
+         *
+         * XXX In Linux, if a thread calls tcsetattr while the monitor thread is
+         * waiting in ioctl for a modem status change then 8250.c wrongly disables
+         * modem irqs and so the monitor thread never gets released. The workaround
+         * is to send a signal after each tcsetattr.
+         *
+         * TIOCMIWAIT doesn't work for the DSR line with TIOCM_DSR set
+         * (see http://lxr.linux.no/#linux+v4.7/drivers/usb/class/cdc-acm.c#L949)
+         * However as it is possible to query the line state we will not just clear
+         * the TIOCM_DSR bit from the lines to check but resort to the polling
+         * approach just like on other hosts.
+         */
+        if (!fPoll)
+        {
+            rcPsx = ioctl(pThis->iFd, TIOCMIWAIT, fStsLinesChk);
+            if (!rcPsx)
+            {
+                rc = rtSerialPortWakeupEvtPoller(pThis, RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_CHANGED);
+                if (RT_FAILURE(rc))
+                    break;
+            }
+            else if (rcPsx == -1 && errno != EINTR)
+                fPoll = true;
+        }
+        else
+#endif
+        {
+            uint32_t fStsLines = 0;
+            rcPsx = ioctl(pThis->iFd, TIOCMGET, &fStsLines);
+            if (!rcPsx)
+            {
+                cStsLineGetErrors = 0; /* Reset the error counter once we had one successful query. */
+
+                if (((fStsLines ^ fStsLinesOld) & fStsLinesChk))
+                {
+                    rc = rtSerialPortWakeupEvtPoller(pThis, RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_CHANGED);
+                    if (RT_FAILURE(rc))
+                        break;
+
+                    fStsLinesOld = fStsLines;
+                }
+                else /* No change, sleep for a bit. */
+                    RTThreadSleep(100 /*ms*/);
+            }
+            else if (rcPsx == -1 && errno != EINTR)
+            {
+                /*
+                 * If querying the status line fails too often we have to shut down the
+                 * thread and notify the user of the serial port.
+                 */
+                if (cStsLineGetErrors++ >= 10)
+                {
+                    rc = RTErrConvertFromErrno(errno);
+                    rtSerialPortWakeupEvtPoller(pThis, RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_MONITOR_FAILED);
+                    break;
+                }
+
+                RTThreadSleep(100 /*ms*/);
+            }
+        }
+    }
+
+    ASMAtomicXchgBool(&pThis->fMonThrdShutdown, true);
+    return rc;
+}
+
+
+/**
+ * Creates the status line monitoring thread.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ */
+static int rtSerialPortMonitorThreadCreate(PRTSERIALPORTINTERNAL pThis)
+{
+    int rc = VINF_SUCCESS;
+
+    /*
+     * Check whether querying the status lines is supported at all, pseudo terminals
+     * don't support it so an error returned in that case.
+     */
+    uint32_t fStsLines = 0;
+    int rcPsx = ioctl(pThis->iFd, TIOCMGET, &fStsLines);
+    if (!rcPsx)
+    {
+        pThis->fMonThrdShutdown = false;
+        rc = RTThreadCreate(&pThis->hMonThrd, rtSerialPortStsLineMonitorThrd, pThis, 0 /*cbStack*/,
+                            RTTHREADTYPE_IO, RTTHREADFLAGS_WAITABLE, "IPRT-SerPortMon");
+        if (RT_SUCCESS(rc))
+        {
+            /* Wait for the thread to start up. */
+            rc = RTThreadUserWait(pThis->hMonThrd, 20*RT_MS_1SEC);
+            if (   rc == VERR_TIMEOUT
+                || pThis->fMonThrdShutdown)
+            {
+                /* Startup failed, try to reap the thread. */
+                int rcThrd;
+                rc = RTThreadWait(pThis->hMonThrd, 20*RT_MS_1SEC, &rcThrd);
+                if (RT_SUCCESS(rc))
+                    rc = rcThrd;
+                else
+                    rc = VERR_INTERNAL_ERROR;
+                /* The thread is lost otherwise. */
+            }
+        }
+    }
+    else if (errno == ENOTTY || errno == EINVAL)
+        rc = VERR_NOT_SUPPORTED;
+    else
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+
+/**
+ * Shuts down the status line monitor thread.
+ *
+ * @param   pThis                   The internal serial port instance data.
+ */
+static void rtSerialPortMonitorThreadShutdown(PRTSERIALPORTINTERNAL pThis)
+{
+    bool fShutDown = ASMAtomicXchgBool(&pThis->fMonThrdShutdown, true);
+    if (!fShutDown)
+    {
+        int rc = RTThreadPoke(pThis->hMonThrd);
+        AssertRC(rc);
+    }
+
+    int rcThrd = VINF_SUCCESS;
+    int rc = RTThreadWait(pThis->hMonThrd, 20*RT_MS_1SEC, &rcThrd);
+    AssertRC(rc);
+    AssertRC(rcThrd);
+}
+
+
+/**
+ * The slow path of rtSerialPortSwitchBlockingMode that does the actual switching.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fBlocking               The desired mode of operation.
+ * @remarks Do not call directly.
+ */
+static int rtSerialPortSwitchBlockingModeSlow(PRTSERIALPORTINTERNAL pThis, bool fBlocking)
+{
+    int fFlags = fcntl(pThis->iFd, F_GETFL, 0);
+    if (fFlags == -1)
+       return RTErrConvertFromErrno(errno);
+
+    if (fBlocking)
+        fFlags &= ~O_NONBLOCK;
+    else
+        fFlags |= O_NONBLOCK;
+    if (fcntl(pThis->iFd, F_SETFL, fFlags) == -1)
+       return RTErrConvertFromErrno(errno);
+
+    pThis->fBlocking = fBlocking;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Switches the serial port to the desired blocking mode if necessary.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fBlocking               The desired mode of operation.
+ */
+DECLINLINE(int) rtSerialPortSwitchBlockingMode(PRTSERIALPORTINTERNAL pThis, bool fBlocking)
+{
+    if (pThis->fBlocking != fBlocking)
+        return rtSerialPortSwitchBlockingModeSlow(pThis, fBlocking);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTSerialPortOpen(PRTSERIALPORT phSerialPort, const char *pszPortAddress, uint32_t fFlags)
+{
+    AssertPtrReturn(phSerialPort, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszPortAddress, VERR_INVALID_POINTER);
+    AssertReturn(*pszPortAddress != '\0', VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSERIALPORT_OPEN_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn((fFlags & RTSERIALPORT_OPEN_F_READ) || (fFlags & RTSERIALPORT_OPEN_F_WRITE),
+                 VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    PRTSERIALPORTINTERNAL pThis = (PRTSERIALPORTINTERNAL)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        int fPsxFlags = O_NOCTTY | O_NONBLOCK;
+
+        if ((fFlags & RTSERIALPORT_OPEN_F_READ) && !(fFlags & RTSERIALPORT_OPEN_F_WRITE))
+            fPsxFlags |= O_RDONLY;
+        else if (!(fFlags & RTSERIALPORT_OPEN_F_READ) && (fFlags & RTSERIALPORT_OPEN_F_WRITE))
+            fPsxFlags |= O_WRONLY;
+        else
+            fPsxFlags |= O_RDWR;
+
+        pThis->u32Magic     = RTSERIALPORT_MAGIC;
+        pThis->fOpenFlags   = fFlags;
+        pThis->fEvtsPending = 0;
+        pThis->iFd          = open(pszPortAddress, fPsxFlags);
+        pThis->fBlocking    = false;
+        if (pThis->iFd != -1)
+        {
+            /* Create wakeup pipe for the event API. */
+            int aPipeFds[2];
+            int rcPsx = pipe(&aPipeFds[0]);
+            if (!rcPsx)
+            {
+                /* Make the pipes close on exec. */
+                pThis->iFdPipeR = aPipeFds[0];
+                pThis->iFdPipeW = aPipeFds[1];
+
+                if (fcntl(pThis->iFdPipeR, F_SETFD, FD_CLOEXEC))
+                    rc = RTErrConvertFromErrno(errno);
+
+                if (   RT_SUCCESS(rc)
+                    && fcntl(pThis->iFdPipeW, F_SETFD, FD_CLOEXEC))
+                    rc = RTErrConvertFromErrno(errno);
+
+                if (RT_SUCCESS(rc))
+                {
+                    rc = rtSerialPortSetDefaultCfg(pThis);
+                    if (   RT_SUCCESS(rc)
+                        && (fFlags & RTSERIALPORT_OPEN_F_SUPPORT_STATUS_LINE_MONITORING))
+                        rc = rtSerialPortMonitorThreadCreate(pThis);
+
+                    if (RT_SUCCESS(rc))
+                    {
+                        *phSerialPort = pThis;
+                        return VINF_SUCCESS;
+                    }
+                }
+
+                close(pThis->iFdPipeR);
+                close(pThis->iFdPipeW);
+            }
+            else
+                rc = RTErrConvertFromErrno(errno);
+
+            close(pThis->iFd);
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortClose(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    if (pThis == NIL_RTSERIALPORT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSERIALPORT_MAGIC_DEAD, RTSERIALPORT_MAGIC), VERR_INVALID_HANDLE);
+
+    if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_SUPPORT_STATUS_LINE_MONITORING)
+        rtSerialPortMonitorThreadShutdown(pThis);
+
+    close(pThis->iFd);
+    close(pThis->iFdPipeR);
+    close(pThis->iFdPipeW);
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTHCINTPTR) RTSerialPortToNative(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, -1);
+
+    return pThis->iFd;
+}
+
+
+RTDECL(int) RTSerialPortRead(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, true);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Attempt read.
+         */
+        ssize_t cbRead = read(pThis->iFd, pvBuf, cbToRead);
+        if (cbRead > 0)
+        {
+            if (pcbRead)
+                /* caller can handle partial read. */
+                *pcbRead = cbRead;
+            else
+            {
+                /* Caller expects all to be read. */
+                while ((ssize_t)cbToRead > cbRead)
+                {
+                    ssize_t cbReadPart = read(pThis->iFd, (uint8_t *)pvBuf + cbRead, cbToRead - cbRead);
+                    if (cbReadPart < 0)
+                        return RTErrConvertFromErrno(errno);
+                    else if (cbReadPart == 0)
+                        return VERR_DEV_IO_ERROR;
+
+                    cbRead += cbReadPart;
+                }
+            }
+        }
+        else if (cbRead == 0)
+            rc = VERR_DEV_IO_ERROR;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortReadNB(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbRead, VERR_INVALID_POINTER);
+
+    *pcbRead = 0;
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, false);
+    if (RT_SUCCESS(rc))
+    {
+        ssize_t cbThisRead = read(pThis->iFd, pvBuf, cbToRead);
+        if (cbThisRead > 0)
+        {
+            /*
+             * The read data needs to be scanned for the BREAK condition marker encoded in the data stream,
+             * if break detection was enabled during open.
+             */
+            if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_DETECT_BREAK_CONDITION)
+            { /** @todo */ }
+
+            *pcbRead = cbThisRead;
+        }
+        else if (cbThisRead == 0)
+            rc = VERR_DEV_IO_ERROR;
+        else if (   errno == EAGAIN
+# ifdef EWOULDBLOCK
+#  if EWOULDBLOCK != EAGAIN
+                 || errno == EWOULDBLOCK
+#  endif
+# endif
+                )
+            rc = VINF_TRY_AGAIN;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWrite(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, true);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Attempt write.
+         */
+        ssize_t cbWritten = write(pThis->iFd, pvBuf, cbToWrite);
+        if (cbWritten > 0)
+        {
+            if (pcbWritten)
+                /* caller can handle partial write. */
+                *pcbWritten = cbWritten;
+            else
+            {
+                /* Caller expects all to be written. */
+                while ((ssize_t)cbToWrite > cbWritten)
+                {
+                    ssize_t cbWrittenPart = write(pThis->iFd, (const uint8_t *)pvBuf + cbWritten, cbToWrite - cbWritten);
+                    if (cbWrittenPart < 0)
+                        return RTErrConvertFromErrno(errno);
+                    else if (cbWrittenPart == 0)
+                        return VERR_DEV_IO_ERROR;
+                    cbWritten += cbWrittenPart;
+                }
+            }
+        }
+        else if (cbWritten == 0)
+            rc = VERR_DEV_IO_ERROR;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWriteNB(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_POINTER);
+
+    *pcbWritten = 0;
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, false);
+    if (RT_SUCCESS(rc))
+    {
+        ssize_t cbThisWrite = write(pThis->iFd, pvBuf, cbToWrite);
+        if (cbThisWrite > 0)
+            *pcbWritten = cbThisWrite;
+        else if (cbThisWrite == 0)
+            rc = VERR_DEV_IO_ERROR;
+        else if (   errno == EAGAIN
+# ifdef EWOULDBLOCK
+#  if EWOULDBLOCK != EAGAIN
+                 || errno == EWOULDBLOCK
+#  endif
+# endif
+                )
+            rc = VINF_TRY_AGAIN;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortCfgQueryCurrent(RTSERIALPORT hSerialPort, PRTSERIALPORTCFG pCfg)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    return rtSerialPortTermios2Cfg(pThis, &pThis->PortCfg, pCfg);
+}
+
+
+RTDECL(int) RTSerialPortCfgSet(RTSERIALPORT hSerialPort, PCRTSERIALPORTCFG pCfg, PRTERRINFO pErrInfo)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    struct termios PortCfgNew; RT_ZERO(PortCfgNew);
+    bool fBaudrateCust = false;
+    int rc = rtSerialPortCfg2Termios(pThis, pCfg, &PortCfgNew, &fBaudrateCust, pErrInfo);
+    if (RT_SUCCESS(rc))
+    {
+        int rcPsx = tcflush(pThis->iFd, TCIOFLUSH);
+        if (!rcPsx)
+        {
+#ifdef RT_OS_LINUX
+            if (fBaudrateCust)
+            {
+                struct serial_struct SerLnx;
+                rcPsx = ioctl(pThis->iFd, TIOCGSERIAL, &SerLnx);
+                if (!rcPsx)
+                {
+                    SerLnx.custom_divisor = SerLnx.baud_base / pCfg->uBaudRate;
+                    if (!SerLnx.custom_divisor)
+                        SerLnx.custom_divisor = 1;
+                    SerLnx.flags &= ~ASYNC_SPD_MASK;
+                    SerLnx.flags |= ASYNC_SPD_CUST;
+                    rcPsx = ioctl(pThis->iFd, TIOCSSERIAL, &SerLnx);
+                }
+            }
+#else /* !RT_OS_LINUX */
+            /* Hosts not supporting custom baud rates should already fail in rtSerialPortCfg2Termios(). */
+            AssertMsgFailed(("Should not get here!\n"));
+#endif /* !RT_OS_LINUX */
+            pThis->fBaudrateCust = fBaudrateCust;
+            pThis->uBaudRateCust = pCfg->uBaudRate;
+
+            if (!rcPsx)
+                rcPsx = tcsetattr(pThis->iFd, TCSANOW, &PortCfgNew);
+            if (rcPsx == -1)
+                rc = RTErrConvertFromErrno(errno);
+            else
+                memcpy(&pThis->PortCfg, &PortCfgNew, sizeof(struct termios));
+
+#ifdef RT_OS_LINUX
+            /*
+             * XXX In Linux, if a thread calls tcsetattr while the monitor thread is
+             * waiting in ioctl for a modem status change then 8250.c wrongly disables
+             * modem irqs and so the monitor thread never gets released. The workaround
+             * is to send a signal after each tcsetattr.
+             */
+            if (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_SUPPORT_STATUS_LINE_MONITORING)
+                RTThreadPoke(pThis->hMonThrd);
+#endif
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPoll(RTSERIALPORT hSerialPort, uint32_t fEvtMask, uint32_t *pfEvtsRecv,
+                                RTMSINTERVAL msTimeout)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fEvtMask & ~RTSERIALPORT_EVT_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfEvtsRecv, VERR_INVALID_POINTER);
+
+    *pfEvtsRecv = 0;
+
+    fEvtMask |= RTSERIALPORT_EVT_F_STATUS_LINE_MONITOR_FAILED; /* This will be reported always, no matter what the caller wants. */
+
+    /* Return early if there are events pending from previous calls which weren't fetched yet. */
+    for (;;)
+    {
+        uint32_t fEvtsPending = ASMAtomicReadU32(&pThis->fEvtsPending);
+        if (fEvtsPending & fEvtMask)
+        {
+            *pfEvtsRecv = fEvtsPending & fEvtMask;
+            /* Write back, repeat the whole procedure if someone else raced us. */
+            if (ASMAtomicCmpXchgU32(&pThis->fEvtsPending, fEvtsPending & ~fEvtMask, fEvtsPending))
+                return VINF_SUCCESS;
+        }
+        else
+            break;
+    }
+
+    int rc = rtSerialPortSwitchBlockingMode(pThis, false);
+    if (RT_SUCCESS(rc))
+    {
+        struct pollfd aPollFds[2]; RT_ZERO(aPollFds);
+        aPollFds[0].fd = pThis->iFd;
+        aPollFds[0].events = POLLERR | POLLHUP;
+        aPollFds[0].revents = 0;
+        if (   (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_READ)
+            && (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX))
+            aPollFds[0].events |= POLLIN;
+        if (   (pThis->fOpenFlags & RTSERIALPORT_OPEN_F_WRITE)
+            && (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX))
+            aPollFds[0].events |= POLLOUT;
+
+        aPollFds[1].fd      = pThis->iFdPipeR;
+        aPollFds[1].events  = POLLIN | POLLERR | POLLHUP;
+        aPollFds[1].revents = 0;
+
+        int rcPsx = 0;
+        int msTimeoutLeft = msTimeout == RT_INDEFINITE_WAIT ? -1 : (int)msTimeout;
+        while (msTimeoutLeft != 0)
+        {
+            uint64_t tsPollStart = RTTimeMilliTS();
+
+            rcPsx = poll(&aPollFds[0], RT_ELEMENTS(aPollFds), msTimeoutLeft);
+            if (rcPsx != -1 || errno != EINTR)
+                break;
+            /* Restart when getting interrupted. */
+            if (msTimeoutLeft > -1)
+            {
+                uint64_t tsPollEnd = RTTimeMilliTS();
+                uint64_t tsPollSpan = tsPollEnd - tsPollStart;
+                msTimeoutLeft -= RT_MIN(tsPollSpan, (uint32_t)msTimeoutLeft);
+            }
+        }
+
+        uint32_t fEvtsPending = 0;
+        if (rcPsx < 0 && errno != EINTR)
+            rc = RTErrConvertFromErrno(errno);
+        else if (rcPsx > 0)
+        {
+            if (aPollFds[0].revents != 0)
+            {
+                if (aPollFds[0].revents & POLLERR)
+                    rc = VERR_DEV_IO_ERROR;
+                else
+                {
+                    fEvtsPending |= (aPollFds[0].revents & POLLIN) ? RTSERIALPORT_EVT_F_DATA_RX : 0;
+                    fEvtsPending |= (aPollFds[0].revents & POLLOUT) ? RTSERIALPORT_EVT_F_DATA_TX : 0;
+                    /** @todo BREAK condition detection. */
+                }
+            }
+
+            if (aPollFds[1].revents != 0)
+            {
+                AssertReturn(!(aPollFds[1].revents & (POLLHUP | POLLERR | POLLNVAL)), VERR_INTERNAL_ERROR);
+                Assert(aPollFds[1].revents & POLLIN);
+
+                uint8_t bWakeupReason = 0;
+                ssize_t cbRead = read(pThis->iFdPipeR, &bWakeupReason, 1);
+                if (cbRead == 1)
+                {
+                    switch (bWakeupReason)
+                    {
+                        case RTSERIALPORT_WAKEUP_PIPE_REASON_INTERRUPT:
+                            rc = VERR_INTERRUPTED;
+                            break;
+                        case RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_CHANGED:
+                            fEvtsPending |= RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED;
+                            break;
+                        case RTSERIALPORT_WAKEUP_PIPE_REASON_STS_LINE_MONITOR_FAILED:
+                            fEvtsPending |= RTSERIALPORT_EVT_F_STATUS_LINE_MONITOR_FAILED;
+                            break;
+                        default:
+                            AssertFailed();
+                            rc = VERR_INTERNAL_ERROR;
+                    }
+                }
+                else
+                    rc = VERR_INTERNAL_ERROR;
+            }
+        }
+        else
+            rc = VERR_TIMEOUT;
+
+        *pfEvtsRecv = fEvtsPending & fEvtMask;
+        fEvtsPending &= ~fEvtMask;
+        ASMAtomicOrU32(&pThis->fEvtsPending, fEvtsPending);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPollInterrupt(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    return rtSerialPortWakeupEvtPoller(pThis, RTSERIALPORT_WAKEUP_PIPE_REASON_INTERRUPT);
+}
+
+
+RTDECL(int) RTSerialPortChgBreakCondition(RTSERIALPORT hSerialPort, bool fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    int rc = VINF_SUCCESS;
+    int rcPsx = ioctl(pThis->iFd, fSet ? TIOCSBRK : TIOCCBRK);
+    if (rcPsx == -1)
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortChgStatusLines(RTSERIALPORT hSerialPort, uint32_t fClear, uint32_t fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    int rc = VINF_SUCCESS;
+    int fTiocmSet = 0;
+    int fTiocmClear = 0;
+
+    if (fClear & RTSERIALPORT_CHG_STS_LINES_F_RTS)
+        fTiocmClear |= TIOCM_RTS;
+    if (fClear & RTSERIALPORT_CHG_STS_LINES_F_DTR)
+        fTiocmClear |= TIOCM_DTR;
+
+    if (fSet & RTSERIALPORT_CHG_STS_LINES_F_RTS)
+        fTiocmSet |= TIOCM_RTS;
+    if (fSet & RTSERIALPORT_CHG_STS_LINES_F_DTR)
+        fTiocmSet |= TIOCM_DTR;
+
+    int rcPsx = ioctl(pThis->iFd, TIOCMBIS, &fTiocmSet);
+    if (!rcPsx)
+    {
+        rcPsx = ioctl(pThis->iFd, TIOCMBIC, &fTiocmClear);
+        if (rcPsx == -1)
+            rc = RTErrConvertFromErrno(errno);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortQueryStatusLines(RTSERIALPORT hSerialPort, uint32_t *pfStsLines)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfStsLines, VERR_INVALID_POINTER);
+
+    *pfStsLines = 0;
+
+    int rc = VINF_SUCCESS;
+    int fStsLines = 0;
+    int rcPsx = ioctl(pThis->iFd, TIOCMGET, &fStsLines);
+    if (!rcPsx)
+    {
+        /* This resets the status line event pending flag. */
+        for (;;)
+        {
+            uint32_t fEvtsPending = ASMAtomicReadU32(&pThis->fEvtsPending);
+            if (ASMAtomicCmpXchgU32(&pThis->fEvtsPending, fEvtsPending & ~RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED, fEvtsPending))
+                break;
+        }
+
+        *pfStsLines |= (fStsLines & TIOCM_CAR) ? RTSERIALPORT_STS_LINE_DCD : 0;
+        *pfStsLines |= (fStsLines & TIOCM_RNG) ? RTSERIALPORT_STS_LINE_RI  : 0;
+        *pfStsLines |= (fStsLines & TIOCM_DSR) ? RTSERIALPORT_STS_LINE_DSR : 0;
+        *pfStsLines |= (fStsLines & TIOCM_CTS) ? RTSERIALPORT_STS_LINE_CTS : 0;
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/shmem-posix.cpp b/src/VBox/Runtime/r3/posix/shmem-posix.cpp
new file mode 100644
index 00000000..5e21f26b
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/shmem-posix.cpp
@@ -0,0 +1,419 @@
+/* $Id: shmem-posix.cpp $ */
+/** @file
+ * IPRT - Named shared memory object, POSIX Implementation.
+ */
+
+/*
+ * Copyright (C) 2018-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/shmem.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include "internal/magics.h"
+
+#include <errno.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+
+/* Workaround on systems which do not provide this. */
+#ifndef NAME_MAX
+# define NAME_MAX 255
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Shared memory object mapping descriptor.
+ */
+typedef struct RTSHMEMMAPPINGDESC
+{
+    /** Number of references held to this mapping, 0 if the descriptor is free. */
+    volatile uint32_t   cMappings;
+    /** Pointer to the region mapping. */
+    void               *pvMapping;
+    /** Start offset */
+    size_t              offRegion;
+    /** Size of the region. */
+    size_t              cbRegion;
+    /** Access flags for this region .*/
+    uint32_t            fFlags;
+} RTSHMEMMAPPINGDESC;
+/** Pointer to a shared memory object mapping descriptor. */
+typedef RTSHMEMMAPPINGDESC *PRTSHMEMMAPPINGDESC;
+/** Pointer to a constant shared memory object mapping descriptor. */
+typedef const RTSHMEMMAPPINGDESC *PCRTSHMEMMAPPINGDESC;
+
+
+/**
+ * Internal shared memory object state.
+ */
+typedef struct RTSHMEMINT
+{
+    /** Magic value (RTSHMEM_MAGIC). */
+    uint32_t            u32Magic;
+    /** File descriptor for the underlying shared memory object. */
+    int                 iFdShm;
+    /** Pointer to the shared memory object name. */
+    char               *pszName;
+    /** Flag whether this instance created the named shared memory object. */
+    bool                fCreate;
+    /** Overall number of mappings active for this shared memory object. */
+    volatile uint32_t   cMappings;
+    /** Maximum number of mapping descriptors allocated. */
+    uint32_t            cMappingDescsMax;
+    /** Number of mapping descriptors used. */
+    volatile uint32_t   cMappingDescsUsed;
+    /** Array of mapping descriptors - variable in size. */
+    RTSHMEMMAPPINGDESC  aMappingDescs[1];
+} RTSHMEMINT;
+/** Pointer to the internal shared memory object state. */
+typedef RTSHMEMINT *PRTSHMEMINT;
+
+
+
+/**
+ * Returns a mapping descriptor matching the given region properties or NULL if none was found.
+ *
+ * @returns Pointer to the matching mapping descriptor or NULL if not found.
+ * @param   pThis           Pointer to the shared memory object instance.
+ * @param   offRegion       Offset into the shared memory object to start mapping at.
+ * @param   cbRegion        Size of the region to map.
+ * @param   fFlags          Desired properties of the mapped region, combination of RTSHMEM_MAP_F_* defines.
+ */
+DECLINLINE(PRTSHMEMMAPPINGDESC) rtShMemMappingDescFindByProp(PRTSHMEMINT pThis, size_t offRegion, size_t cbRegion, uint32_t fFlags)
+{
+    for (uint32_t i = 0; i < pThis->cMappingDescsMax; i++)
+    {
+        if (   pThis->aMappingDescs[i].offRegion == offRegion
+            && pThis->aMappingDescs[i].cbRegion == cbRegion
+            && pThis->aMappingDescs[i].fFlags == fFlags)
+            return &pThis->aMappingDescs[i];
+    }
+
+    return NULL;
+}
+
+
+RTDECL(int) RTShMemOpen(PRTSHMEM phShMem, const char *pszName, uint32_t fFlags, size_t cbMax, uint32_t cMappingsHint)
+{
+    AssertPtrReturn(phShMem, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSHMEM_O_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(cMappingsHint < 64, VERR_OUT_OF_RANGE);
+
+    size_t cchName = strlen(pszName);
+    AssertReturn(cchName, VERR_INVALID_PARAMETER);
+    AssertReturn(cchName < NAME_MAX - 1, VERR_INVALID_PARAMETER); /* account for the / we add later on. */
+    cMappingsHint = cMappingsHint == 0 ? 5 : cMappingsHint;
+    int rc = VINF_SUCCESS;
+    PRTSHMEMINT pThis = (PRTSHMEMINT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTSHMEMINT, aMappingDescs[cMappingsHint]) + cchName + 2); /* '/' + terminator. */
+    if (RT_LIKELY(pThis))
+    {
+        pThis->u32Magic            = RTSHMEM_MAGIC;
+        pThis->pszName             = (char *)&pThis->aMappingDescs[cMappingsHint];
+        /*pThis->fCreate           = false; */
+        /*pThis->cMappings         = 0; */
+        pThis->cMappingDescsMax    = cMappingsHint;
+        /*pThis->cMappingDescsUsed = 0; */
+        pThis->pszName[0]          = '/';
+        memcpy(&pThis->pszName[1], pszName, cchName);
+        int fShmFlags = 0;
+        if (fFlags & RTSHMEM_O_F_CREATE)
+        {
+            fShmFlags |= O_CREAT;
+            pThis->fCreate = true;
+        }
+        if ((fFlags & RTSHMEM_O_F_CREATE_EXCL) == RTSHMEM_O_F_CREATE_EXCL)
+            fShmFlags |= O_EXCL;
+        if (   (fFlags & RTSHMEM_O_F_READWRITE) == RTSHMEM_O_F_READWRITE
+            || (fFlags & RTSHMEM_O_F_WRITE))
+            fShmFlags |= O_RDWR;
+        else
+            fShmFlags |= O_RDONLY;
+        if (fFlags & RTSHMEM_O_F_TRUNCATE)
+            fShmFlags |= O_TRUNC;
+        pThis->iFdShm = shm_open(pThis->pszName, fShmFlags , 0600);
+        if (pThis->iFdShm > 0)
+        {
+            if (cbMax)
+                rc = RTShMemSetSize(pThis, cbMax);
+            if (RT_SUCCESS(rc))
+            {
+                *phShMem = pThis;
+                return VINF_SUCCESS;
+            }
+
+            close(pThis->iFdShm);
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemClose(RTSHMEM hShMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->cMappings, VERR_INVALID_STATE);
+
+    int rc = VINF_SUCCESS;
+    if (!close(pThis->iFdShm))
+    {
+        if (pThis->fCreate)
+            shm_unlink(pThis->pszName); /* Ignore any error here. */
+        pThis->u32Magic = RTSHMEM_MAGIC_DEAD;
+        RTMemFree(pThis);
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemDelete(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+
+    size_t cchName = strlen(pszName);
+    AssertReturn(cchName, VERR_INVALID_PARAMETER);
+    AssertReturn(cchName < NAME_MAX - 1, VERR_INVALID_PARAMETER); /* account for the / we add later on. */
+    char *psz = NULL;
+
+    int rc = RTStrAllocEx(&psz, cchName + 2); /* '/' + terminator */
+    if (RT_SUCCESS(rc))
+    {
+        psz[0] = '/';
+        memcpy(&psz[1], pszName, cchName + 1);
+        if (shm_unlink(psz))
+            rc = RTErrConvertFromErrno(errno);
+        RTStrFree(psz);
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTShMemRefCount(RTSHMEM hShMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, 0);
+
+    return pThis->cMappings;
+}
+
+
+RTDECL(int) RTShMemSetSize(RTSHMEM hShMem, size_t cbMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->cMappings, VERR_INVALID_STATE);
+
+    int rc = VINF_SUCCESS;
+    if (ftruncate(pThis->iFdShm, (off_t)cbMem))
+        rc = RTErrConvertFromErrno(errno);
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemQuerySize(RTSHMEM hShMem, size_t *pcbMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pcbMem, VERR_INVALID_PARAMETER);
+
+    struct stat st;
+    if (!fstat(pThis->iFdShm, &st))
+    {
+        *pcbMem = st.st_size;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(int) RTShMemMapRegion(RTSHMEM hShMem, size_t offRegion, size_t cbRegion, uint32_t fFlags, void **ppv)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(ppv, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSHMEM_MAP_F_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /* Try to find a mapping with compatible parameters first. */
+    PRTSHMEMMAPPINGDESC pMappingDesc = NULL;
+    for (uint32_t iTry = 0; iTry < 10; iTry++)
+    {
+        pMappingDesc = rtShMemMappingDescFindByProp(pThis, offRegion, cbRegion, fFlags);
+        if (!pMappingDesc)
+            break;
+
+        /* Increase the mapping count and check that the region is still accessible by us. */
+        if (   ASMAtomicIncU32(&pMappingDesc->cMappings) > 1
+            && pMappingDesc->offRegion == offRegion
+            && pMappingDesc->cbRegion  == cbRegion
+            && pMappingDesc->fFlags    == fFlags)
+            break;
+        /* Mapping was freed inbetween, next round. */
+    }
+
+    int rc = VINF_SUCCESS;
+    if (!pMappingDesc)
+    {
+        /* Find an empty region descriptor and map the region. */
+        for (uint32_t i = 0; i < pThis->cMappingDescsMax && !pMappingDesc; i++)
+        {
+            if (!pThis->aMappingDescs[i].cMappings)
+            {
+                pMappingDesc = &pThis->aMappingDescs[i];
+
+                /* Try to grab this one. */
+                if (ASMAtomicIncU32(&pMappingDesc->cMappings) == 1)
+                    break;
+
+                /* Somebody raced us, drop reference and continue. */
+                ASMAtomicDecU32(&pMappingDesc->cMappings);
+                pMappingDesc = NULL;
+            }
+        }
+
+        if (RT_LIKELY(pMappingDesc))
+        {
+            /* Try to map it. */
+            int fMmapFlags = 0;
+            int fProt = 0;
+            if (fFlags & RTSHMEM_MAP_F_READ)
+                fProt |= PROT_READ;
+            if (fFlags & RTSHMEM_MAP_F_WRITE)
+                fProt |= PROT_WRITE;
+            if (fFlags & RTSHMEM_MAP_F_EXEC)
+                fProt |= PROT_EXEC;
+            if (fFlags & RTSHMEM_MAP_F_COW)
+                fMmapFlags |= MAP_PRIVATE;
+            else
+                fMmapFlags |= MAP_SHARED;
+
+            void *pv = mmap(NULL, cbRegion, fProt, fMmapFlags, pThis->iFdShm, (off_t)offRegion);
+            if (pv != MAP_FAILED)
+            {
+                pMappingDesc->pvMapping = pv;
+                pMappingDesc->offRegion = offRegion;
+                pMappingDesc->cbRegion  = cbRegion;
+                pMappingDesc->fFlags    = fFlags;
+            }
+            else
+            {
+                rc = RTErrConvertFromErrno(errno);
+                ASMAtomicDecU32(&pMappingDesc->cMappings);
+            }
+        }
+        else
+            rc = VERR_SHMEM_MAXIMUM_MAPPINGS_REACHED;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        *ppv = pMappingDesc->pvMapping;
+        ASMAtomicIncU32(&pThis->cMappings);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemUnmapRegion(RTSHMEM hShMem, void *pv)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pv, VERR_INVALID_PARAMETER);
+
+    /* Find the mapping descriptor by the given region address. */
+    PRTSHMEMMAPPINGDESC pMappingDesc = NULL;
+    for (uint32_t i = 0; i < pThis->cMappingDescsMax && !pMappingDesc; i++)
+    {
+        if (pThis->aMappingDescs[i].pvMapping == pv)
+        {
+            pMappingDesc = &pThis->aMappingDescs[i];
+            break;
+        }
+    }
+
+    AssertPtrReturn(pMappingDesc, VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    size_t cbRegion = pMappingDesc->cMappings;
+    if (!ASMAtomicDecU32(&pMappingDesc->cMappings))
+    {
+        /* Last mapping of this region was unmapped, so do the real unmapping now. */
+        if (munmap(pv, cbRegion))
+        {
+            ASMAtomicIncU32(&pMappingDesc->cMappings);
+            rc = RTErrConvertFromErrno(errno);
+        }
+        else
+        {
+            ASMAtomicDecU32(&pThis->cMappingDescsUsed);
+            ASMAtomicDecU32(&pThis->cMappings);
+        }
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/symlink-posix.cpp b/src/VBox/Runtime/r3/posix/symlink-posix.cpp
new file mode 100644
index 00000000..e43f5b36
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/symlink-posix.cpp
@@ -0,0 +1,247 @@
+/* $Id: symlink-posix.cpp $ */
+/** @file
+ * IPRT - Symbolic Links, POSIX.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYMLINK
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <iprt/symlink.h>
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include "internal/path.h"
+
+
+
+RTDECL(bool) RTSymlinkExists(const char *pszSymlink)
+{
+    bool fRc = false;
+    char const *pszNativeSymlink;
+    int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat s;
+        fRc = !lstat(pszNativeSymlink, &s)
+            && S_ISLNK(s.st_mode);
+
+        rtPathFreeNative(pszNativeSymlink, pszSymlink);
+    }
+
+    LogFlow(("RTSymlinkExists(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
+    return fRc;
+}
+
+
+RTDECL(bool) RTSymlinkIsDangling(const char *pszSymlink)
+{
+    bool fRc = false;
+    char const *pszNativeSymlink;
+    int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat s;
+        fRc = !lstat(pszNativeSymlink, &s)
+            && S_ISLNK(s.st_mode);
+        if (fRc)
+        {
+            errno = 0;
+            fRc = stat(pszNativeSymlink, &s) != 0
+               && (   errno == ENOENT
+                   || errno == ENOTDIR
+                   || errno == ELOOP);
+        }
+
+        rtPathFreeNative(pszNativeSymlink, pszSymlink);
+    }
+
+    LogFlow(("RTSymlinkIsDangling(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
+    return fRc;
+}
+
+
+RTDECL(int) RTSymlinkCreate(const char *pszSymlink, const char *pszTarget, RTSYMLINKTYPE enmType, uint32_t fCreate)
+{
+    RT_NOREF_PV(fCreate);
+
+    /*
+     * Validate the input.
+     */
+    AssertReturn(enmType > RTSYMLINKTYPE_INVALID && enmType < RTSYMLINKTYPE_END, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszSymlink, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszTarget, VERR_INVALID_POINTER);
+
+    /*
+     * Convert the paths.
+     */
+    char const *pszNativeSymlink;
+    int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        const char *pszNativeTarget;
+        rc = rtPathToNative(&pszNativeTarget, pszTarget, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Create the link.
+             */
+            if (symlink(pszNativeTarget, pszNativeSymlink) == 0)
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromErrno(errno);
+
+            rtPathFreeNative(pszNativeTarget, pszTarget);
+        }
+        rtPathFreeNative(pszNativeSymlink, pszSymlink);
+    }
+
+    LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d, %#x): returns %Rrc\n", pszSymlink, pszSymlink, pszTarget, pszTarget, enmType, fCreate, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkDelete(const char *pszSymlink, uint32_t fDelete)
+{
+    RT_NOREF_PV(fDelete);
+
+    char const *pszNativeSymlink;
+    int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        struct stat s;
+        if (!lstat(pszNativeSymlink, &s))
+        {
+            if (S_ISLNK(s.st_mode))
+            {
+                if (unlink(pszNativeSymlink) == 0)
+                    rc = VINF_SUCCESS;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+            }
+            else
+                rc = VERR_NOT_SYMLINK;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+        rtPathFreeNative(pszNativeSymlink, pszSymlink);
+    }
+
+    LogFlow(("RTSymlinkDelete(%p={%s}, #%x): returns %Rrc\n", pszSymlink, pszSymlink, fDelete, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkRead(const char *pszSymlink, char *pszTarget, size_t cbTarget, uint32_t fRead)
+{
+    RT_NOREF_PV(fRead);
+
+    char *pszMyTarget;
+    int rc = RTSymlinkReadA(pszSymlink, &pszMyTarget);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTStrCopy(pszTarget, cbTarget, pszMyTarget);
+        RTStrFree(pszMyTarget);
+    }
+    LogFlow(("RTSymlinkRead(%p={%s}): returns %Rrc\n", pszSymlink, pszSymlink, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkReadA(const char *pszSymlink, char **ppszTarget)
+{
+    AssertPtr(ppszTarget);
+    char const *pszNativeSymlink;
+    int rc = rtPathToNative(&pszNativeSymlink, pszSymlink, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        /* Guess the initial buffer size. */
+        ssize_t     cbBuf;
+        struct stat s;
+        if (!lstat(pszNativeSymlink, &s))
+            cbBuf = RT_MAX(RT_ALIGN_Z(s.st_size, 64), 64);
+        else
+            cbBuf = 1024;
+
+        /* Read loop that grows the buffer. */
+        char *pszBuf = NULL;
+        for (;;)
+        {
+            RTMemTmpFree(pszBuf);
+            pszBuf = (char *)RTMemTmpAlloc(cbBuf);
+            if (pszBuf)
+            {
+                ssize_t cbReturned = readlink(pszNativeSymlink, pszBuf, cbBuf);
+                if (cbReturned >= cbBuf)
+                {
+                    /* Increase the buffer size and try again */
+                    cbBuf *= 2;
+                    continue;
+                }
+
+                if (cbReturned > 0)
+                {
+                    pszBuf[cbReturned] = '\0';
+                    rc = rtPathFromNativeDup(ppszTarget, pszBuf, pszSymlink);
+                }
+                else if (errno == EINVAL)
+                    rc = VERR_NOT_SYMLINK;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+            }
+            else
+                rc = VERR_NO_TMP_MEMORY;
+            break;
+        } /* for loop */
+
+        RTMemTmpFree(pszBuf);
+        rtPathFreeNative(pszNativeSymlink, pszSymlink);
+    }
+
+    if (RT_SUCCESS(rc))
+        LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc *ppszTarget=%p:{%s}\n", pszSymlink, pszSymlink, ppszTarget, rc, *ppszTarget, *ppszTarget));
+    else
+        LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc\n", pszSymlink, pszSymlink, ppszTarget, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/thread-posix.cpp b/src/VBox/Runtime/r3/posix/thread-posix.cpp
new file mode 100644
index 00000000..cd621ce0
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/thread-posix.cpp
@@ -0,0 +1,780 @@
+/* $Id: thread-posix.cpp $ */
+/** @file
+ * IPRT - Threads, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+#if defined(RT_OS_LINUX)
+# include <unistd.h>
+# include <sys/syscall.h>
+#endif
+#if defined(RT_OS_SOLARIS)
+# include <sched.h>
+# include <sys/resource.h>
+#endif
+#if defined(RT_OS_DARWIN)
+# include <mach/thread_act.h>
+# include <mach/thread_info.h>
+# include <mach/host_info.h>
+# include <mach/mach_init.h>
+# include <mach/mach_host.h>
+#endif
+#if defined(RT_OS_DARWIN) /*|| defined(RT_OS_FREEBSD) - later */ \
+ || (defined(RT_OS_LINUX) && !defined(IN_RT_STATIC) /* static + dlsym = trouble */) \
+ || defined(IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP)
+# define IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP
+# include <dlfcn.h>
+#endif
+#if defined(RT_OS_HAIKU)
+# include <OS.h>
+#endif
+#if defined(RT_OS_DARWIN)
+# define sigprocmask pthread_sigmask /* On xnu sigprocmask works on the process, not the calling thread as elsewhere. */
+#endif
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/asm.h>
+#include <iprt/err.h>
+#include <iprt/initterm.h>
+#include <iprt/string.h>
+#include <iprt/semaphore.h>
+#include <iprt/list.h>
+#include <iprt/once.h>
+#include <iprt/critsect.h>
+#include <iprt/req.h>
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/*#ifndef IN_GUEST - shouldn't need to exclude this now with the non-obtrusive init option. */
+/** Includes RTThreadPoke. */
+# define RTTHREAD_POSIX_WITH_POKE
+/*#endif*/
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The pthread key in which we store the pointer to our own PRTTHREAD structure.
+ * @note There is a defined NIL value here, nor can we really assume this is an
+ *       integer.  However, zero is a valid key on Linux, so we get into trouble
+ *       if we accidentally use it uninitialized.
+ *
+ *       So, we ASSUME it's a integer value and the valid range is in approx 0
+ *       to PTHREAD_KEYS_MAX.  Solaris has at least one negative value (-1)
+ *       defined.  Thus, we go for 16 MAX values below zero and keep our fingers
+ *       cross that it will always be an invalid key value everywhere...
+ *
+ *       See also NIL_RTTLS, which is -1.
+ */
+static pthread_key_t    g_SelfKey = (pthread_key_t)(-PTHREAD_KEYS_MAX * 16);
+#ifdef RTTHREAD_POSIX_WITH_POKE
+/** The signal we use for poking threads.
+ * This is set to -1 if no available signal was found. */
+static int volatile     g_iSigPokeThread = -1;
+#endif
+
+#ifdef IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP
+# if defined(RT_OS_DARWIN)
+/**
+ * The Mac OS X (10.6 and later) variant of pthread_setname_np.
+ *
+ * @returns errno.h
+ * @param   pszName         The new thread name.
+ */
+typedef int (*PFNPTHREADSETNAME)(const char *pszName);
+# else
+/**
+ * The variant of pthread_setname_np most other unix-like systems implement.
+ *
+ * @returns errno.h
+ * @param   hThread         The thread.
+ * @param   pszName         The new thread name.
+ */
+typedef int (*PFNPTHREADSETNAME)(pthread_t hThread, const char *pszName);
+# endif
+
+/** Pointer to pthread_setname_np if found. */
+static PFNPTHREADSETNAME g_pfnThreadSetName = NULL;
+#endif /* IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP */
+
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+/** Atomic indicator of whether the priority proxy thread has been (attempted) started.
+ *
+ * The priority proxy thread is started under these circumstances:
+ *      - RTThreadCreate
+ *      - RTThreadSetType
+ *      - RTProcSetPriority
+ *
+ * Which means that we'll be single threaded when this is modified.
+ *
+ * Speical values:
+ *      - VERR_TRY_AGAIN:           Not yet started.
+ *      - VERR_WRONG_ORDER:         Starting.
+ *      - VINF_SUCCESS:             Started successfully.
+ *      - VERR_PROCESS_NOT_FOUND:   Stopping or stopped
+ *      - Other error status if failed to start.
+ *
+ * @note We could potentially optimize this by only start it when we lower the
+ *       priority of ourselves, the process, or a newly created thread.  But
+ *       that would means we would need to take multi-threading into account, so
+ *       let's not do that for now.
+ */
+static int32_t volatile g_rcPriorityProxyThreadStart            = VERR_TRY_AGAIN;
+/** The IPRT thread handle for the priority proxy. */
+static RTTHREAD         g_hRTThreadPosixPriorityProxyThread     = NIL_RTTHREAD;
+/** The priority proxy queue. */
+static RTREQQUEUE       g_hRTThreadPosixPriorityProxyQueue      = NIL_RTREQQUEUE;
+#endif /* RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY */
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static void *rtThreadNativeMain(void *pvArgs);
+static void rtThreadKeyDestruct(void *pvValue);
+#ifdef RTTHREAD_POSIX_WITH_POKE
+static void rtThreadPosixPokeSignal(int iSignal);
+#endif
+
+
+#ifdef RTTHREAD_POSIX_WITH_POKE
+/**
+ * Try register the dummy signal handler for RTThreadPoke.
+ */
+static void rtThreadPosixSelectPokeSignal(void)
+{
+    /*
+     * Note! Avoid SIGRTMIN thru SIGRTMIN+2 because of LinuxThreads.
+     */
+# if !defined(RT_OS_LINUX) && !defined(RT_OS_SOLARIS) /* glibc defines SIGRTMAX to __libc_current_sigrtmax() and Solaris libc defines it relying on _sysconf(), causing compiler to deploy serialization here. */
+    static
+# endif
+    const int s_aiSigCandidates[] =
+    {
+# ifdef SIGRTMAX
+        SIGRTMAX-3,
+        SIGRTMAX-2,
+        SIGRTMAX-1,
+# endif
+# ifndef RT_OS_SOLARIS
+        SIGUSR2,
+# endif
+        SIGWINCH
+    };
+
+    g_iSigPokeThread = -1;
+    if (!RTR3InitIsUnobtrusive())
+    {
+        for (unsigned iSig = 0; iSig < RT_ELEMENTS(s_aiSigCandidates); iSig++)
+        {
+            struct sigaction SigActOld;
+            if (!sigaction(s_aiSigCandidates[iSig], NULL, &SigActOld))
+            {
+                if (   SigActOld.sa_handler == SIG_DFL
+                    || SigActOld.sa_handler == rtThreadPosixPokeSignal)
+                {
+                    struct sigaction SigAct;
+                    RT_ZERO(SigAct);
+                    SigAct.sa_handler = rtThreadPosixPokeSignal;
+                    SigAct.sa_flags   = 0;      /* no SA_RESTART! */
+                    sigfillset(&SigAct.sa_mask);
+
+                    /* ASSUMES no sigaction race... (lazy bird) */
+                    if (!sigaction(s_aiSigCandidates[iSig], &SigAct, NULL))
+                    {
+                        g_iSigPokeThread = s_aiSigCandidates[iSig];
+                        break;
+                    }
+                    AssertMsgFailed(("rc=%Rrc errno=%d\n", RTErrConvertFromErrno(errno), errno));
+                }
+            }
+            else
+                AssertMsgFailed(("rc=%Rrc errno=%d\n", RTErrConvertFromErrno(errno), errno));
+        }
+    }
+}
+#endif /* RTTHREAD_POSIX_WITH_POKE */
+
+
+DECLHIDDEN(int) rtThreadNativeInit(void)
+{
+    /*
+     * Allocate the TLS (key in posix terms) where we store the pointer to
+     * a threads RTTHREADINT structure.
+     */
+    int rc = pthread_key_create(&g_SelfKey, rtThreadKeyDestruct);
+    if (rc)
+        return VERR_NO_TLS_FOR_SELF;
+
+#ifdef RTTHREAD_POSIX_WITH_POKE
+    rtThreadPosixSelectPokeSignal();
+#endif
+
+#ifdef IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP
+    if (RT_SUCCESS(rc))
+        g_pfnThreadSetName = (PFNPTHREADSETNAME)(uintptr_t)dlsym(RTLD_DEFAULT, "pthread_setname_np");
+#endif
+    return rc;
+}
+
+static void rtThreadPosixBlockSignals(PRTTHREADINT pThread)
+{
+    /*
+     * Mask all signals, including the poke one, if requested.
+     */
+    if (   pThread
+        && (pThread->fFlags & RTTHREADFLAGS_NO_SIGNALS))
+    {
+        sigset_t SigSet;
+        sigfillset(&SigSet);
+        sigdelset(&SigSet, SIGILL);  /* On the m1 we end up spinning on UDF ... */
+        sigdelset(&SigSet, SIGTRAP); /* ... and BRK instruction if these signals are masked. */
+        sigdelset(&SigSet, SIGFPE);  /* Just adding the rest here to be on the safe side. */
+        sigdelset(&SigSet, SIGBUS);
+        sigdelset(&SigSet, SIGSEGV);
+        int rc = sigprocmask(SIG_BLOCK, &SigSet, NULL);
+        AssertMsg(rc == 0, ("rc=%Rrc errno=%d\n", RTErrConvertFromErrno(errno), errno)); RT_NOREF(rc);
+    }
+    /*
+     * Block SIGALRM - required for timer-posix.cpp.
+     * This is done to limit harm done by OSes which doesn't do special SIGALRM scheduling.
+     * It will not help much if someone creates threads directly using pthread_create. :/
+     */
+    else if (!RTR3InitIsUnobtrusive())
+    {
+        sigset_t SigSet;
+        sigemptyset(&SigSet);
+        sigaddset(&SigSet, SIGALRM);
+        sigprocmask(SIG_BLOCK, &SigSet, NULL);
+    }
+
+#ifdef RTTHREAD_POSIX_WITH_POKE
+    /*
+     * bird 2020-10-28: Not entirely sure why we do this, but it makes sure the signal works
+     *                  on the new thread.  Probably some pre-NPTL linux reasons.
+     */
+    if (g_iSigPokeThread != -1)
+    {
+# if 1 /* siginterrupt() is typically implemented as two sigaction calls, this should be faster and w/o deprecations: */
+        struct sigaction SigActOld;
+        RT_ZERO(SigActOld);
+
+        struct sigaction SigAct;
+        RT_ZERO(SigAct);
+        SigAct.sa_handler = rtThreadPosixPokeSignal;
+        SigAct.sa_flags   = 0;          /* no SA_RESTART! */
+        sigfillset(&SigAct.sa_mask);
+
+        int rc = sigaction(g_iSigPokeThread, &SigAct, &SigActOld);
+        AssertMsg(rc == 0, ("rc=%Rrc errno=%d\n", RTErrConvertFromErrno(errno), errno)); RT_NOREF(rc);
+        AssertMsg(rc || SigActOld.sa_handler == rtThreadPosixPokeSignal, ("%p\n", SigActOld.sa_handler));
+# else
+        siginterrupt(g_iSigPokeThread, 1);
+# endif
+    }
+#endif
+}
+
+DECLHIDDEN(void) rtThreadNativeReInitObtrusive(void)
+{
+#ifdef RTTHREAD_POSIX_WITH_POKE
+    Assert(!RTR3InitIsUnobtrusive());
+    rtThreadPosixSelectPokeSignal();
+#endif
+    rtThreadPosixBlockSignals(NULL);
+}
+
+
+/**
+ * Destructor called when a thread terminates.
+ * @param   pvValue     The key value. PRTTHREAD in our case.
+ */
+static void rtThreadKeyDestruct(void *pvValue)
+{
+    /*
+     * Deal with alien threads.
+     */
+    PRTTHREADINT pThread = (PRTTHREADINT)pvValue;
+    if (pThread->fIntFlags & RTTHREADINT_FLAGS_ALIEN)
+    {
+        pthread_setspecific(g_SelfKey, pThread);
+        rtThreadTerminate(pThread, 0);
+        pthread_setspecific(g_SelfKey, NULL);
+    }
+}
+
+
+#ifdef RTTHREAD_POSIX_WITH_POKE
+/**
+ * Dummy signal handler for the poke signal.
+ *
+ * @param   iSignal     The signal number.
+ */
+static void rtThreadPosixPokeSignal(int iSignal)
+{
+    Assert(iSignal == g_iSigPokeThread);
+    NOREF(iSignal);
+}
+#endif
+
+
+/**
+ * Adopts a thread, this is called immediately after allocating the
+ * thread structure.
+ *
+ * @param   pThread     Pointer to the thread structure.
+ */
+DECLHIDDEN(int) rtThreadNativeAdopt(PRTTHREADINT pThread)
+{
+    rtThreadPosixBlockSignals(pThread);
+
+    int rc = pthread_setspecific(g_SelfKey, pThread);
+    if (!rc)
+        return VINF_SUCCESS;
+    return VERR_FAILED_TO_SET_SELF_TLS;
+}
+
+
+DECLHIDDEN(void) rtThreadNativeDestroy(PRTTHREADINT pThread)
+{
+    if (pThread == (PRTTHREADINT)pthread_getspecific(g_SelfKey))
+        pthread_setspecific(g_SelfKey, NULL);
+}
+
+
+/**
+ * Wrapper which unpacks the params and calls thread function.
+ */
+static void *rtThreadNativeMain(void *pvArgs)
+{
+    PRTTHREADINT  pThread = (PRTTHREADINT)pvArgs;
+    pthread_t     Self    = pthread_self();
+#if !defined(RT_OS_SOLARIS) /* On Solaris sizeof(pthread_t) = 4 and sizeof(NIL_RTNATIVETHREAD) = 8 */
+    Assert((uintptr_t)Self != NIL_RTNATIVETHREAD);
+#endif
+    Assert(Self == (pthread_t)(RTNATIVETHREAD)Self);
+
+#if defined(RT_OS_LINUX)
+    /*
+     * Set the TID.
+     */
+    pThread->tid = syscall(__NR_gettid);
+    ASMMemoryFence();
+#endif
+
+    rtThreadPosixBlockSignals(pThread);
+
+    /*
+     * Set the TLS entry and, if possible, the thread name.
+     */
+    int rc = pthread_setspecific(g_SelfKey, pThread);
+    AssertReleaseMsg(!rc, ("failed to set self TLS. rc=%d thread '%s'\n", rc, pThread->szName));
+
+#ifdef IPRT_MAY_HAVE_PTHREAD_SET_NAME_NP
+    if (g_pfnThreadSetName)
+# ifdef RT_OS_DARWIN
+        g_pfnThreadSetName(pThread->szName);
+# else
+        g_pfnThreadSetName(Self, pThread->szName);
+# endif
+#endif
+
+    /*
+     * Call common main.
+     */
+    rc = rtThreadMain(pThread, (uintptr_t)Self, &pThread->szName[0]);
+
+    pthread_setspecific(g_SelfKey, NULL);
+    pthread_exit((void *)(intptr_t)rc);
+    return (void *)(intptr_t)rc;
+}
+
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+
+/**
+ * @callback_method_impl{FNRTTHREAD,
+ *  Priority proxy thread that services g_hRTThreadPosixPriorityProxyQueue.}
+ */
+static DECLCALLBACK(int) rtThreadPosixPriorityProxyThread(PRTTHREADINT, void *)
+{
+    for (;;)
+    {
+        RTREQQUEUE hReqQueue = g_hRTThreadPosixPriorityProxyQueue;
+        if (hReqQueue != NIL_RTREQQUEUE)
+            RTReqQueueProcess(hReqQueue, RT_INDEFINITE_WAIT);
+        else
+            break;
+
+        int32_t rc = ASMAtomicUoReadS32(&g_rcPriorityProxyThreadStart);
+        if (rc != VINF_SUCCESS && rc != VERR_WRONG_ORDER)
+            break;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Just returns a non-success status codes to force the thread to re-evaluate
+ * the global shutdown variable.
+ */
+static DECLCALLBACK(int) rtThreadPosixPriorityProxyStopper(void)
+{
+    return VERR_CANCELLED;
+}
+
+
+/**
+ * An atexit() callback that stops the proxy creation/priority thread.
+ */
+static void rtThreadStopProxyThread(void)
+{
+    /*
+     * Signal to the thread that it's time to shut down.
+     */
+    int32_t rc = ASMAtomicXchgS32(&g_rcPriorityProxyThreadStart, VERR_PROCESS_NOT_FOUND);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Grab the associated handles.
+         */
+        RTTHREAD   hThread = g_hRTThreadPosixPriorityProxyThread;
+        RTREQQUEUE hQueue  = g_hRTThreadPosixPriorityProxyQueue;
+        g_hRTThreadPosixPriorityProxyQueue  = NIL_RTREQQUEUE;
+        g_hRTThreadPosixPriorityProxyThread = NIL_RTTHREAD;
+        ASMCompilerBarrier(); /* paranoia */
+
+        AssertReturnVoid(hThread != NIL_RTTHREAD);
+        AssertReturnVoid(hQueue != NIL_RTREQQUEUE);
+
+        /*
+         * Kick the thread so it gets out of any pending RTReqQueueProcess call ASAP.
+         */
+        rc = RTReqQueueCallEx(hQueue, NULL, 0 /*cMillies*/, RTREQFLAGS_IPRT_STATUS | RTREQFLAGS_NO_WAIT,
+                              (PFNRT)rtThreadPosixPriorityProxyStopper, 0);
+
+        /*
+         * Wait for the thread to complete.
+         */
+        rc = RTThreadWait(hThread, RT_SUCCESS(rc) ? RT_MS_1SEC * 5 : 32, NULL);
+        if (RT_SUCCESS(rc))
+            RTReqQueueDestroy(hQueue);
+        /* else: just leak the stuff, we're exitting, so nobody cares... */
+    }
+}
+
+
+/**
+ * Ensure that the proxy priority proxy thread has been started.
+ *
+ * Since we will always start a proxy thread when asked to create a thread,
+ * there is no need for serialization here.
+ *
+ * @retval  true if started
+ * @retval  false if it failed to start (caller must handle this scenario).
+ */
+DECLHIDDEN(bool) rtThreadPosixPriorityProxyStart(void)
+{
+    /*
+     * Read the result.
+     */
+    int rc = ASMAtomicUoReadS32(&g_rcPriorityProxyThreadStart);
+    if (rc != VERR_TRY_AGAIN)
+        return RT_SUCCESS(rc);
+
+    /* If this triggers then there is a very unexpected race somewhere.  It
+       should be harmless though. */
+    AssertReturn(ASMAtomicCmpXchgS32(&g_rcPriorityProxyThreadStart, VERR_WRONG_ORDER, VERR_TRY_AGAIN), false);
+
+    /*
+     * Not yet started, so do that.
+     */
+    rc = RTReqQueueCreate(&g_hRTThreadPosixPriorityProxyQueue);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTThreadCreate(&g_hRTThreadPosixPriorityProxyThread, rtThreadPosixPriorityProxyThread, NULL, 0 /*cbStack*/,
+                            RTTHREADTYPE_DEFAULT, RTTHREADFLAGS_WAITABLE, "RTThrdPP");
+        if (RT_SUCCESS(rc))
+        {
+            ASMAtomicWriteS32(&g_rcPriorityProxyThreadStart, VINF_SUCCESS);
+
+            atexit(rtThreadStopProxyThread);
+            return true;
+        }
+        RTReqQueueCreate(&g_hRTThreadPosixPriorityProxyQueue);
+    }
+    ASMAtomicWriteS32(&g_rcPriorityProxyThreadStart, rc != VERR_WRONG_ORDER ? rc : VERR_PROCESS_NOT_FOUND);
+    return false;
+}
+
+
+/**
+ * Calls @a pfnFunction from the priority proxy thread.
+ *
+ * Caller must have called rtThreadPosixStartProxy() to check that the priority
+ * proxy thread is running.
+ *
+ * @returns
+ * @param   pTargetThread   The target thread, NULL if not applicable.  This is
+ *                          so we can skip calls pertaining to the priority
+ *                          proxy thread itself.
+ * @param   pfnFunction     The function to call.  Must return IPRT status code.
+ * @param   cArgs           Number of arguments (see also RTReqQueueCall).
+ * @param   ...             Arguments (see also RTReqQueueCall).
+ */
+DECLHIDDEN(int) rtThreadPosixPriorityProxyCall(PRTTHREADINT pTargetThread, PFNRT pfnFunction, int cArgs, ...)
+{
+    int rc;
+    if (   !pTargetThread
+        || pTargetThread->pfnThread != rtThreadPosixPriorityProxyThread)
+    {
+        va_list va;
+        va_start(va, cArgs);
+        PRTREQ pReq;
+        rc = RTReqQueueCallV(g_hRTThreadPosixPriorityProxyQueue, &pReq, RT_INDEFINITE_WAIT, RTREQFLAGS_IPRT_STATUS,
+                             pfnFunction, cArgs, va);
+        va_end(va);
+        RTReqRelease(pReq);
+    }
+    else
+        rc = VINF_SUCCESS;
+    return rc;
+}
+
+#endif /* !RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY */
+
+/**
+ * Worker for rtThreadNativeCreate that's either called on the priority proxy
+ * thread or directly on the calling thread depending on the proxy state.
+ */
+static DECLCALLBACK(int) rtThreadNativeInternalCreate(PRTTHREADINT pThread, PRTNATIVETHREAD pNativeThread)
+{
+    /*
+     * Set the default stack size.
+     */
+    if (!pThread->cbStack)
+        pThread->cbStack = 512*1024;
+
+#ifdef RT_OS_LINUX
+    pThread->tid = -1;
+#endif
+
+    /*
+     * Setup thread attributes.
+     */
+    pthread_attr_t  ThreadAttr;
+    int rc = pthread_attr_init(&ThreadAttr);
+    if (!rc)
+    {
+        rc = pthread_attr_setdetachstate(&ThreadAttr, PTHREAD_CREATE_DETACHED);
+        if (!rc)
+        {
+            rc = pthread_attr_setstacksize(&ThreadAttr, pThread->cbStack);
+            if (!rc)
+            {
+                /*
+                 * Create the thread.
+                 */
+                pthread_t ThreadId;
+                rc = pthread_create(&ThreadId, &ThreadAttr, rtThreadNativeMain, pThread);
+                if (!rc)
+                {
+                    pthread_attr_destroy(&ThreadAttr);
+                    *pNativeThread = (uintptr_t)ThreadId;
+                    return VINF_SUCCESS;
+                }
+            }
+        }
+        pthread_attr_destroy(&ThreadAttr);
+    }
+    return RTErrConvertFromErrno(rc);
+}
+
+
+DECLHIDDEN(int) rtThreadNativeCreate(PRTTHREADINT pThread, PRTNATIVETHREAD pNativeThread)
+{
+#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
+    /*
+     * If we have a priority proxy thread, use it.  Make sure to ignore the
+     * staring of the proxy thread itself.
+     */
+    if (   pThread->pfnThread != rtThreadPosixPriorityProxyThread
+        && rtThreadPosixPriorityProxyStart())
+    {
+        PRTREQ pReq;
+        int rc = RTReqQueueCall(g_hRTThreadPosixPriorityProxyQueue, &pReq, RT_INDEFINITE_WAIT,
+                                (PFNRT)rtThreadNativeInternalCreate, 2, pThread, pNativeThread);
+        RTReqRelease(pReq);
+        return rc;
+    }
+
+    /*
+     * Fall back on creating it directly without regard to priority proxying.
+     */
+#endif
+    return rtThreadNativeInternalCreate(pThread, pNativeThread);
+}
+
+
+RTDECL(RTTHREAD) RTThreadSelf(void)
+{
+    /** @todo import alien threads? */
+#if defined(RT_OS_DARWIN)
+    /* On darwin, there seems to be input checking with pthread_getspecific.
+       So, we must prevent using g_SelfKey before rtThreadNativeInit has run,
+       otherwise we might crash or starting working with total garbage pointer
+       values here (see _os_tsd_get_direct in znu/libsyscall/os/tsd.h).
+
+       Now, since the init value is a "negative" one, we just have to check
+       that it's positive or zero before calling the API. */
+    if (RT_LIKELY((intptr_t)g_SelfKey >= 0))
+        return (PRTTHREADINT)pthread_getspecific(g_SelfKey);
+    return NIL_RTTHREAD;
+#else
+    return (PRTTHREADINT)pthread_getspecific(g_SelfKey);
+#endif
+}
+
+
+#ifdef RTTHREAD_POSIX_WITH_POKE
+
+RTDECL(int) RTThreadPoke(RTTHREAD hThread)
+{
+    AssertReturn(hThread != RTThreadSelf(), VERR_INVALID_PARAMETER);
+    PRTTHREADINT pThread = rtThreadGet(hThread);
+    AssertReturn(pThread, VERR_INVALID_HANDLE);
+
+    int rc;
+    if (g_iSigPokeThread != -1)
+    {
+        rc = pthread_kill((pthread_t)(uintptr_t)pThread->Core.Key, g_iSigPokeThread);
+        rc = RTErrConvertFromErrno(rc);
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+
+    rtThreadRelease(pThread);
+    return rc;
+}
+
+
+RTDECL(int) RTThreadControlPokeSignal(RTTHREAD hThread, bool fEnable)
+{
+    AssertReturn(hThread == RTThreadSelf() && hThread != NIL_RTTHREAD, VERR_INVALID_PARAMETER);
+    int rc;
+    if (g_iSigPokeThread != -1)
+    {
+        sigset_t SigSet;
+        sigemptyset(&SigSet);
+        sigaddset(&SigSet, g_iSigPokeThread);
+
+        int rc2 = sigprocmask(fEnable ? SIG_UNBLOCK : SIG_BLOCK, &SigSet, NULL);
+        if (rc2 == 0)
+            rc = VINF_SUCCESS;
+        else
+        {
+            rc = RTErrConvertFromErrno(errno);
+            AssertMsgFailed(("rc=%Rrc errno=%d (rc2=%d)\n", rc, errno, rc2));
+        }
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
+
+#endif
+
+/** @todo move this into platform specific files. */
+RTR3DECL(int) RTThreadGetExecutionTimeMilli(uint64_t *pKernelTime, uint64_t *pUserTime)
+{
+#if defined(RT_OS_SOLARIS)
+    struct rusage ts;
+    int rc = getrusage(RUSAGE_LWP, &ts);
+    if (rc)
+        return RTErrConvertFromErrno(rc);
+
+    *pKernelTime = ts.ru_stime.tv_sec * 1000 + ts.ru_stime.tv_usec / 1000;
+    *pUserTime   = ts.ru_utime.tv_sec * 1000 + ts.ru_utime.tv_usec / 1000;
+    return VINF_SUCCESS;
+
+#elif defined(RT_OS_LINUX) || defined(RT_OS_FREEBSD)
+    /* on Linux, getrusage(RUSAGE_THREAD, ...) is available since 2.6.26 */
+    struct timespec ts;
+    int rc = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
+    if (rc)
+        return RTErrConvertFromErrno(rc);
+
+    *pKernelTime = 0;
+    *pUserTime = (uint64_t)ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
+    return VINF_SUCCESS;
+
+#elif defined(RT_OS_DARWIN)
+    thread_basic_info       ThreadInfo;
+    mach_msg_type_number_t  Count = THREAD_BASIC_INFO_COUNT;
+    kern_return_t krc = thread_info(mach_thread_self(), THREAD_BASIC_INFO, (thread_info_t)&ThreadInfo, &Count);
+    AssertReturn(krc == KERN_SUCCESS, RTErrConvertFromDarwinKern(krc));
+
+    *pKernelTime = ThreadInfo.system_time.seconds * 1000 + ThreadInfo.system_time.microseconds / 1000;
+    *pUserTime   = ThreadInfo.user_time.seconds   * 1000 + ThreadInfo.user_time.microseconds   / 1000;
+
+    return VINF_SUCCESS;
+#elif defined(RT_OS_HAIKU)
+    thread_info       ThreadInfo;
+    status_t status = get_thread_info(find_thread(NULL), &ThreadInfo);
+    AssertReturn(status == B_OK, RTErrConvertFromErrno(status));
+
+    *pKernelTime = ThreadInfo.kernel_time / 1000;
+    *pUserTime   = ThreadInfo.user_time / 1000;
+
+    return VINF_SUCCESS;
+#else
+    return VERR_NOT_IMPLEMENTED;
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/posix/thread2-posix.cpp b/src/VBox/Runtime/r3/posix/thread2-posix.cpp
new file mode 100644
index 00000000..6eaee22e
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/thread2-posix.cpp
@@ -0,0 +1,133 @@
+/* $Id: thread2-posix.cpp $ */
+/** @file
+ * IPRT - Threads part 2, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <errno.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <sched.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/asm.h>
+#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+# include <iprt/asm-amd64-x86.h>
+#endif
+#include <iprt/errcore.h>
+#include "internal/thread.h"
+
+
+RTDECL(RTNATIVETHREAD) RTThreadNativeSelf(void)
+{
+    return (RTNATIVETHREAD)pthread_self();
+}
+
+
+RTDECL(int) RTThreadSleep(RTMSINTERVAL cMillies)
+{
+    LogFlow(("RTThreadSleep: cMillies=%d\n", cMillies));
+    if (!cMillies)
+    {
+        if (!sched_yield())
+        {
+            LogFlow(("RTThreadSleep: returning %Rrc (cMillies=%d)\n", VINF_SUCCESS, cMillies));
+            return VINF_SUCCESS;
+        }
+    }
+    else
+    {
+        struct timespec ts;
+        struct timespec tsrem = {0,0};
+
+        ts.tv_nsec = (cMillies % 1000) * 1000000;
+        ts.tv_sec  = cMillies / 1000;
+        if (!nanosleep(&ts, &tsrem))
+        {
+            LogFlow(("RTThreadSleep: returning %Rrc (cMillies=%d)\n", VINF_SUCCESS, cMillies));
+            return VINF_SUCCESS;
+        }
+    }
+
+    int rc = RTErrConvertFromErrno(errno);
+    LogFlow(("RTThreadSleep: returning %Rrc (cMillies=%d)\n", rc, cMillies));
+    return rc;
+}
+
+
+RTDECL(int) RTThreadSleepNoLog(RTMSINTERVAL cMillies)
+{
+    if (!cMillies)
+    {
+        if (!sched_yield())
+            return VINF_SUCCESS;
+    }
+    else
+    {
+        struct timespec ts;
+        struct timespec tsrem = {0,0};
+
+        ts.tv_nsec = (cMillies % 1000) * 1000000;
+        ts.tv_sec  = cMillies / 1000;
+        if (!nanosleep(&ts, &tsrem))
+            return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTDECL(bool) RTThreadYield(void)
+{
+#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+    uint64_t u64TS = ASMReadTSC();
+#endif
+
+    sched_yield();
+
+#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
+    u64TS = ASMReadTSC() - u64TS;
+    bool fRc = u64TS > 1500;
+    LogFlow(("RTThreadYield: returning %d (%llu ticks)\n", fRc, u64TS));
+#else
+    bool fRc = true; /* PORTME: Add heuristics for determining whether the cpus was yielded. */
+#endif
+    return fRc;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/time-posix.cpp b/src/VBox/Runtime/r3/posix/time-posix.cpp
new file mode 100644
index 00000000..3c028b73
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/time-posix.cpp
@@ -0,0 +1,99 @@
+/* $Id: time-posix.cpp $ */
+/** @file
+ * IPRT - Time, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <sys/time.h>
+#include <time.h>
+
+#include <iprt/time.h>
+#include "internal/time.h"
+
+
+DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
+{
+#if defined(CLOCK_MONOTONIC) && !defined(RT_OS_L4) && !defined(RT_OS_OS2)
+    /* check monotonic clock first. */
+    static bool s_fMonoClock = true;
+    if (s_fMonoClock)
+    {
+        struct timespec ts;
+        if (!clock_gettime(CLOCK_MONOTONIC, &ts))
+            return (uint64_t)ts.tv_sec * RT_NS_1SEC_64
+                 + ts.tv_nsec;
+        s_fMonoClock = false;
+    }
+#endif
+
+    /* fallback to gettimeofday(). */
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    return (uint64_t)tv.tv_sec  * RT_NS_1SEC_64
+         + (uint64_t)(tv.tv_usec * RT_NS_1US);
+}
+
+
+/**
+ * Gets the current nanosecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns nanosecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+/**
+ * Gets the current millisecond timestamp.
+ *
+ * This differs from RTTimeNanoTS in that it will use system APIs and not do any
+ * resolution or performance optimizations.
+ *
+ * @returns millisecond timestamp.
+ */
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/timelocal-posix.cpp b/src/VBox/Runtime/r3/posix/timelocal-posix.cpp
new file mode 100644
index 00000000..40e2fc16
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/timelocal-posix.cpp
@@ -0,0 +1,215 @@
+/* $Id $ */
+/** @file
+ * IPRT - Local Time, Posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define RTTIME_INCL_TIMEVAL
+#include <iprt/types.h>
+#include <iprt/assert.h>
+
+#include <sys/time.h>
+#include <time.h>
+
+#include <iprt/time.h>
+
+
+/**
+ * This tries to find the UTC offset for a given timespec.
+ *
+ * It does probably not take into account changes in daylight
+ * saving over the years or similar stuff.
+ *
+ * @returns UTC offset in nanoseconds.
+ * @param   pTime           The time.
+ * @param   fCurrentTime    Whether the input is current time or not.
+ *                          This is for avoid infinit recursion on errors in the fallback path.
+ */
+static int64_t rtTimeLocalUTCOffset(PCRTTIMESPEC pTime, bool fCurrentTime)
+{
+    RTTIMESPEC Fallback;
+
+    /*
+     * Convert to time_t.
+     */
+    int64_t i64UnixTime = RTTimeSpecGetSeconds(pTime);
+    time_t UnixTime = i64UnixTime;
+    if (UnixTime != i64UnixTime)
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+
+    /*
+     * Explode it as both local and UTC time.
+     */
+    struct tm TmLocal;
+    if (    !localtime_r(&UnixTime, &TmLocal)
+        ||  !TmLocal.tm_year)
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+    struct tm TmUtc;
+    if (!gmtime_r(&UnixTime, &TmUtc))
+        return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
+
+    /*
+     * Calc the difference (if any).
+     * We ASSUME that the difference is less that 24 hours.
+     */
+    if (    TmLocal.tm_hour == TmUtc.tm_hour
+        &&  TmLocal.tm_min  == TmUtc.tm_min
+        &&  TmLocal.tm_sec  == TmUtc.tm_sec
+        &&  TmLocal.tm_mday == TmUtc.tm_mday)
+        return 0;
+
+    int cLocalSecs = TmLocal.tm_hour * 3600
+                   + TmLocal.tm_min * 60
+                   + TmLocal.tm_sec;
+    int cUtcSecs   = TmUtc.tm_hour * 3600
+                   + TmUtc.tm_min * 60
+                   + TmUtc.tm_sec;
+    if (TmLocal.tm_mday != TmUtc.tm_mday)
+    {
+        /*
+         * Must add 24 hours to the value that is ahead of the other.
+         *
+         * To determine which is ahead was busted for a long long time (bugref:9078),
+         * so here are some examples and two different approaches.
+         *
+         *  TmLocal              TmUtc              => Add 24:00 to     => Diff
+         *  2007-04-02 01:00     2007-04-01 23:00   => TmLocal          => +02:00
+         *  2007-04-01 01:00     2007-03-31 23:00   => TmLocal          => +02:00
+         *  2007-03-31 01:00     2007-03-30 23:00   => TmLocal          => +02:00
+         *
+         *  2007-04-01 01:00     2007-04-02 23:00   => TmUtc            => -02:00
+         *  2007-03-31 23:00     2007-04-01 01:00   => TmUtc            => -02:00
+         *  2007-03-30 23:00     2007-03-31 01:00   => TmUtc            => -02:00
+         *
+         */
+#if 0
+        /* Using day of month turned out to be a little complicated. */
+        if (   (   TmLocal.tm_mday > TmUtc.tm_mday
+                && (TmUtc.tm_mday != 1 || TmLocal.tm_mday < 28) )
+            || (TmLocal.tm_mday == 1 && TmUtc.tm_mday >= 28) )
+        {
+            cLocalSecs += 24*60*60;
+            Assert(   TmLocal.tm_yday - TmUtc.tm_yday == 1
+                   || (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
+        }
+        else
+        {
+            cUtcSecs   += 24*60*60;
+            Assert(   TmUtc.tm_yday - TmLocal.tm_yday == 1
+                   || (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
+        }
+#else
+        /* Using day of year and year is simpler. */
+        if (   (   TmLocal.tm_year == TmUtc.tm_year
+                && TmLocal.tm_yday > TmUtc.tm_yday)
+            || TmLocal.tm_year > TmUtc.tm_year)
+        {
+            cLocalSecs += 24*60*60;
+            Assert(   TmLocal.tm_yday - TmUtc.tm_yday == 1
+                   || (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
+        }
+        else
+        {
+            cUtcSecs   += 24*60*60;
+            Assert(   TmUtc.tm_yday - TmLocal.tm_yday == 1
+                   || (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
+        }
+#endif
+    }
+
+    return (cLocalSecs - cUtcSecs) * INT64_C(1000000000);
+}
+
+
+/**
+ * Gets the current delta between UTC and local time.
+ *
+ * @code
+ *      RTTIMESPEC LocalTime;
+ *      RTTimeSpecAddNano(RTTimeNow(&LocalTime), RTTimeLocalDeltaNano());
+ * @endcode
+ *
+ * @returns Returns the nanosecond delta between UTC and local time.
+ */
+RTDECL(int64_t) RTTimeLocalDeltaNano(void)
+{
+    RTTIMESPEC Time;
+    return rtTimeLocalUTCOffset(RTTimeNow(&Time), true /* current time, skip fallback */);
+}
+
+
+/**
+ * Gets the delta between UTC and local time at the given time.
+ *
+ * @code
+ *      RTTIMESPEC LocalTime;
+ *      RTTimeNow(&LocalTime);
+ *      RTTimeSpecAddNano(&LocalTime, RTTimeLocalDeltaNanoFor(&LocalTime));
+ * @endcode
+ *
+ * @param   pTimeSpec   The time spec giving the time to get the delta for.
+ * @returns Returns the nanosecond delta between UTC and local time.
+ */
+RTDECL(int64_t) RTTimeLocalDeltaNanoFor(PCRTTIMESPEC pTimeSpec)
+{
+    AssertPtr(pTimeSpec);
+    return rtTimeLocalUTCOffset(pTimeSpec, false /* current time, skip fallback */);
+}
+
+
+/**
+ * Explodes a time spec to the localized timezone.
+ *
+ * @returns pTime.
+ * @param   pTime       Where to store the exploded time.
+ * @param   pTimeSpec   The time spec to exploded. (UTC)
+ */
+RTDECL(PRTTIME) RTTimeLocalExplode(PRTTIME pTime, PCRTTIMESPEC pTimeSpec)
+{
+    RTTIMESPEC LocalTime = *pTimeSpec;
+    int64_t cNsUtcOffset = rtTimeLocalUTCOffset(&LocalTime, true /* current time, skip fallback */);
+    RTTimeSpecAddNano(&LocalTime, cNsUtcOffset);
+    pTime = RTTimeExplode(pTime, &LocalTime);
+    if (pTime)
+    {
+        pTime->fFlags = (pTime->fFlags & ~RTTIME_FLAGS_TYPE_MASK) | RTTIME_FLAGS_TYPE_LOCAL;
+        pTime->offUTC = cNsUtcOffset / RT_NS_1MIN;
+    }
+    return pTime;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/timer-posix.cpp b/src/VBox/Runtime/r3/posix/timer-posix.cpp
new file mode 100644
index 00000000..59c905b9
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/timer-posix.cpp
@@ -0,0 +1,847 @@
+/* $Id: timer-posix.cpp $ */
+/** @file
+ * IPRT - Timer, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Enables the use of POSIX RT timers. */
+#ifndef RT_OS_SOLARIS /* Solaris 10 doesn't have SIGEV_THREAD */
+# define IPRT_WITH_POSIX_TIMERS
+#endif /* !RT_OS_SOLARIS */
+
+/** @def RT_TIMER_SIGNAL
+ * The signal number that the timers use.
+ * We currently use SIGALRM for both setitimer and posix real time timers
+ * out of simplicity, but we might want change this later for the posix ones. */
+#ifdef IPRT_WITH_POSIX_TIMERS
+# define RT_TIMER_SIGNAL    SIGALRM
+#else
+# define RT_TIMER_SIGNAL    SIGALRM
+#endif
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP   RTLOGGROUP_TIMER
+#include <iprt/timer.h>
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/asm.h>
+#include <iprt/semaphore.h>
+#include <iprt/string.h>
+#include <iprt/once.h>
+#include <iprt/err.h>
+#include <iprt/initterm.h>
+#include <iprt/critsect.h>
+#include "internal/magics.h"
+
+#include <unistd.h>
+#include <sys/fcntl.h>
+#include <sys/ioctl.h>
+#ifdef RT_OS_LINUX
+# include <linux/rtc.h>
+#endif
+#include <sys/time.h>
+#include <signal.h>
+#include <errno.h>
+#include <pthread.h>
+#if defined(RT_OS_DARWIN)
+# define sigprocmask pthread_sigmask /* On xnu sigprocmask works on the process, not the calling thread as elsewhere. */
+#endif
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#ifdef IPRT_WITH_POSIX_TIMERS
+/** Init the critsect on first call. */
+static RTONCE g_TimerOnce = RTONCE_INITIALIZER;
+/** Global critsect that serializes timer creation and destruction.
+ * This is lazily created on the first RTTimerCreateEx call and will not be
+ * freed up (I'm afraid).  */
+static RTCRITSECT g_TimerCritSect;
+/**
+ * Global counter of RTTimer instances. The signal thread is
+ * started when it changes from 0 to 1. The signal thread
+ * terminates when it becomes 0 again.
+ */
+static uint32_t volatile g_cTimerInstances;
+/** The signal handling thread. */
+static RTTHREAD g_TimerThread;
+#endif /* IPRT_WITH_POSIX_TIMERS */
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * The internal representation of a timer handle.
+ */
+typedef struct RTTIMER
+{
+    /** Magic.
+     * This is RTTIMER_MAGIC, but changes to something else before the timer
+     * is destroyed to indicate clearly that thread should exit. */
+    uint32_t volatile       u32Magic;
+    /** Flag indicating the timer is suspended. */
+    uint8_t volatile        fSuspended;
+    /** Flag indicating that the timer has been destroyed. */
+    uint8_t volatile        fDestroyed;
+#ifndef IPRT_WITH_POSIX_TIMERS /** @todo We have to take the signals on a dedicated timer thread as
+                                * we (might) have code assuming that signals doesn't screw around
+                                * on existing threads. (It would be sufficient to have one thread
+                                * per signal of course since the signal will be masked while it's
+                                * running, however, it may just cause more complications than its
+                                * worth - sigwait/sigwaitinfo work atomically anyway...)
+                                * Also, must block the signal in the thread main procedure too. */
+    /** The timer thread. */
+    RTTHREAD                Thread;
+    /** Event semaphore on which the thread is blocked. */
+    RTSEMEVENT              Event;
+#endif /* !IPRT_WITH_POSIX_TIMERS */
+    /** User argument. */
+    void                   *pvUser;
+    /** Callback. */
+    PFNRTTIMER              pfnTimer;
+    /** The timer interval. 0 if one-shot. */
+    uint64_t                u64NanoInterval;
+#ifndef IPRT_WITH_POSIX_TIMERS
+    /** The first shot interval. 0 if ASAP. */
+    uint64_t volatile       u64NanoFirst;
+#endif /* !IPRT_WITH_POSIX_TIMERS */
+    /** The current timer tick. */
+    uint64_t volatile       iTick;
+#ifndef IPRT_WITH_POSIX_TIMERS
+    /** The error/status of the timer.
+     * Initially -1, set to 0 when the timer have been successfully started, and
+     * to errno on failure in starting the timer. */
+    int volatile            iError;
+#else /* IPRT_WITH_POSIX_TIMERS */
+    timer_t                 NativeTimer;
+#endif /* IPRT_WITH_POSIX_TIMERS */
+
+} RTTIMER;
+
+
+
+#ifdef IPRT_WITH_POSIX_TIMERS
+
+/**
+ * RTOnce callback that initializes the critical section.
+ *
+ * @returns RTCritSectInit return code.
+ * @param   pvUser      NULL, ignored.
+ *
+ */
+static DECLCALLBACK(int) rtTimerOnce(void *pvUser)
+{
+    NOREF(pvUser);
+    return RTCritSectInit(&g_TimerCritSect);
+}
+#endif
+
+
+/**
+ * Signal handler which ignore everything it gets.
+ *
+ * @param   iSignal     The signal number.
+ */
+static void rttimerSignalIgnore(int iSignal)
+{
+    //AssertBreakpoint();
+    NOREF(iSignal);
+}
+
+
+/**
+ * RT_TIMER_SIGNAL wait thread.
+ */
+static DECLCALLBACK(int) rttimerThread(RTTHREAD hThreadSelf, void *pvArg)
+{
+    NOREF(hThreadSelf); NOREF(pvArg);
+#ifndef IPRT_WITH_POSIX_TIMERS
+    PRTTIMER pTimer = (PRTTIMER)pvArg;
+    RTTIMER Timer = *pTimer;
+    Assert(pTimer->u32Magic == RTTIMER_MAGIC);
+#endif /* !IPRT_WITH_POSIX_TIMERS */
+
+    /*
+     * Install signal handler.
+     */
+    struct sigaction SigAct;
+    memset(&SigAct, 0, sizeof(SigAct));
+    SigAct.sa_flags = SA_RESTART;
+    sigemptyset(&SigAct.sa_mask);
+    SigAct.sa_handler = rttimerSignalIgnore;
+    if (sigaction(RT_TIMER_SIGNAL, &SigAct, NULL))
+    {
+        SigAct.sa_flags &= ~SA_RESTART;
+        if (sigaction(RT_TIMER_SIGNAL, &SigAct, NULL))
+            AssertMsgFailed(("sigaction failed, errno=%d\n", errno));
+    }
+
+    /*
+     * Mask most signals except those which might be used by the pthread implementation (linux).
+     */
+    sigset_t SigSet;
+    sigfillset(&SigSet);
+    sigdelset(&SigSet, SIGTERM);
+    sigdelset(&SigSet, SIGHUP);
+    sigdelset(&SigSet, SIGINT);
+    sigdelset(&SigSet, SIGABRT);
+    sigdelset(&SigSet, SIGKILL);
+#ifdef SIGRTMIN
+    for (int iSig = SIGRTMIN; iSig < SIGRTMAX; iSig++)
+        sigdelset(&SigSet, iSig);
+#endif
+    if (sigprocmask(SIG_SETMASK, &SigSet, NULL))
+    {
+#ifdef IPRT_WITH_POSIX_TIMERS
+        int rc = RTErrConvertFromErrno(errno);
+#else
+        int rc = pTimer->iError = RTErrConvertFromErrno(errno);
+#endif
+        AssertMsgFailed(("sigprocmask -> errno=%d\n", errno));
+        return rc;
+    }
+
+    /*
+     * The work loop.
+     */
+    RTThreadUserSignal(hThreadSelf);
+
+#ifndef IPRT_WITH_POSIX_TIMERS
+    while (     !pTimer->fDestroyed
+           &&   pTimer->u32Magic == RTTIMER_MAGIC)
+    {
+        /*
+         * Wait for a start or destroy event.
+         */
+        if (pTimer->fSuspended)
+        {
+            int rc = RTSemEventWait(pTimer->Event, RT_INDEFINITE_WAIT);
+            if (RT_FAILURE(rc) && rc != VERR_INTERRUPTED)
+            {
+                AssertRC(rc);
+                if (pTimer->fDestroyed)
+                    continue;
+                RTThreadSleep(1000); /* Don't cause trouble! */
+            }
+            if (    pTimer->fSuspended
+                ||  pTimer->fDestroyed)
+                continue;
+        }
+
+        /*
+         * Start the timer.
+         *
+         * For some SunOS (/SysV?) threading compatibility Linux will only
+         * deliver the RT_TIMER_SIGNAL to the thread calling setitimer(). Therefore
+         * we have to call it here.
+         *
+         * It turns out this might not always be the case, see RT_TIMER_SIGNAL killing
+         * processes on RH 2.4.21.
+         */
+        struct itimerval TimerVal;
+        if (pTimer->u64NanoFirst)
+        {
+            uint64_t u64 = RT_MAX(1000, pTimer->u64NanoFirst);
+            TimerVal.it_value.tv_sec     = u64 / 1000000000;
+            TimerVal.it_value.tv_usec    = (u64 % 1000000000) / 1000;
+        }
+        else
+        {
+            TimerVal.it_value.tv_sec     = 0;
+            TimerVal.it_value.tv_usec    = 10;
+        }
+        if (pTimer->u64NanoInterval)
+        {
+            uint64_t u64 = RT_MAX(1000, pTimer->u64NanoInterval);
+            TimerVal.it_interval.tv_sec  = u64 / 1000000000;
+            TimerVal.it_interval.tv_usec = (u64 % 1000000000) / 1000;
+        }
+        else
+        {
+            TimerVal.it_interval.tv_sec  = 0;
+            TimerVal.it_interval.tv_usec = 0;
+        }
+
+        if (setitimer(ITIMER_REAL, &TimerVal, NULL))
+        {
+            ASMAtomicXchgU8(&pTimer->fSuspended, true);
+            pTimer->iError = RTErrConvertFromErrno(errno);
+            RTThreadUserSignal(hThreadSelf);
+            continue; /* back to suspended mode. */
+        }
+        pTimer->iError = 0;
+        RTThreadUserSignal(hThreadSelf);
+
+        /*
+         * Timer Service Loop.
+         */
+        sigemptyset(&SigSet);
+        sigaddset(&SigSet, RT_TIMER_SIGNAL);
+        do
+        {
+            siginfo_t SigInfo;
+            RT_ZERO(SigInfo);
+#ifdef RT_OS_DARWIN
+            if (RT_LIKELY(sigwait(&SigSet, &SigInfo.si_signo) >= 0))
+            {
+#else
+            if (RT_LIKELY(sigwaitinfo(&SigSet, &SigInfo) >= 0))
+            {
+                if (RT_LIKELY(SigInfo.si_signo == RT_TIMER_SIGNAL))
+#endif
+                {
+                    if (RT_UNLIKELY(    pTimer->fSuspended
+                                    ||  pTimer->fDestroyed
+                                    ||  pTimer->u32Magic != RTTIMER_MAGIC))
+                        break;
+
+                    pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pTimer->iTick);
+
+                    /* auto suspend one-shot timers. */
+                    if (RT_UNLIKELY(!pTimer->u64NanoInterval))
+                    {
+                        ASMAtomicWriteU8(&pTimer->fSuspended, true);
+                        break;
+                    }
+                }
+            }
+            else if (errno != EINTR)
+                AssertMsgFailed(("sigwaitinfo -> errno=%d\n", errno));
+        } while (RT_LIKELY(   !pTimer->fSuspended
+                           && !pTimer->fDestroyed
+                           &&  pTimer->u32Magic == RTTIMER_MAGIC));
+
+        /*
+         * Disable the timer.
+         */
+        struct itimerval TimerVal2 = {{0,0}, {0,0}};
+        if (setitimer(ITIMER_REAL, &TimerVal2, NULL))
+            AssertMsgFailed(("setitimer(ITIMER_REAL,&{0}, NULL) failed, errno=%d\n", errno));
+
+        /*
+         * ACK any pending suspend request.
+         */
+        if (!pTimer->fDestroyed)
+        {
+            pTimer->iError = 0;
+            RTThreadUserSignal(hThreadSelf);
+        }
+    }
+
+    /*
+     * Exit.
+     */
+    pTimer->iError = 0;
+    RTThreadUserSignal(hThreadSelf);
+
+#else /* IPRT_WITH_POSIX_TIMERS */
+
+    sigemptyset(&SigSet);
+    sigaddset(&SigSet, RT_TIMER_SIGNAL);
+    while (g_cTimerInstances)
+    {
+        siginfo_t SigInfo;
+        RT_ZERO(SigInfo);
+        if (RT_LIKELY(sigwaitinfo(&SigSet, &SigInfo) >= 0))
+        {
+            LogFlow(("rttimerThread: signo=%d pTimer=%p\n", SigInfo.si_signo, SigInfo.si_value.sival_ptr));
+            if (RT_LIKELY(   SigInfo.si_signo == RT_TIMER_SIGNAL
+                          && SigInfo.si_code == SI_TIMER)) /* The SI_TIMER check is *essential* because of the pthread_kill. */
+            {
+                PRTTIMER pTimer = (PRTTIMER)SigInfo.si_value.sival_ptr;
+                AssertPtr(pTimer);
+                if (RT_UNLIKELY(    !RT_VALID_PTR(pTimer)
+                                ||  ASMAtomicUoReadU8(&pTimer->fSuspended)
+                                ||  ASMAtomicUoReadU8(&pTimer->fDestroyed)
+                                ||  pTimer->u32Magic != RTTIMER_MAGIC))
+                    continue;
+
+                pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pTimer->iTick);
+
+                /* auto suspend one-shot timers. */
+                if (RT_UNLIKELY(!pTimer->u64NanoInterval))
+                    ASMAtomicWriteU8(&pTimer->fSuspended, true);
+            }
+        }
+    }
+#endif /* IPRT_WITH_POSIX_TIMERS */
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTTimerCreateEx(PRTTIMER *ppTimer, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMER pfnTimer, void *pvUser)
+{
+    /*
+     * We don't support the fancy MP features.
+     */
+    if (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC)
+        return VERR_NOT_SUPPORTED;
+
+    /*
+     * We need the signal masks to be set correctly, which they won't be in
+     * unobtrusive mode.
+     */
+    if (RTR3InitIsUnobtrusive())
+        return VERR_NOT_SUPPORTED;
+
+#ifndef IPRT_WITH_POSIX_TIMERS
+    /*
+     * Check if timer is busy.
+     */
+    struct itimerval TimerVal;
+    if (getitimer(ITIMER_REAL, &TimerVal))
+    {
+        AssertMsgFailed(("getitimer() -> errno=%d\n", errno));
+        return VERR_NOT_IMPLEMENTED;
+    }
+    if (    TimerVal.it_value.tv_usec
+        ||  TimerVal.it_value.tv_sec
+        ||  TimerVal.it_interval.tv_usec
+        ||  TimerVal.it_interval.tv_sec)
+    {
+        AssertMsgFailed(("A timer is running. System limit is one timer per process!\n"));
+        return VERR_TIMER_BUSY;
+    }
+#endif /* !IPRT_WITH_POSIX_TIMERS */
+
+    /*
+     * Block RT_TIMER_SIGNAL from calling thread.
+     */
+    sigset_t SigSet;
+    sigemptyset(&SigSet);
+    sigaddset(&SigSet, RT_TIMER_SIGNAL);
+    sigprocmask(SIG_BLOCK, &SigSet, NULL);
+
+#ifndef IPRT_WITH_POSIX_TIMERS /** @todo combine more of the setitimer/timer_create code. setitimer could also use the global thread. */
+    /** @todo Move this RTC hack else where... */
+    static bool fDoneRTC;
+    if (!fDoneRTC)
+    {
+        fDoneRTC = true;
+        /* check resolution. */
+        TimerVal.it_interval.tv_sec = 0;
+        TimerVal.it_interval.tv_usec = 1000;
+        TimerVal.it_value = TimerVal.it_interval;
+        if (    setitimer(ITIMER_REAL, &TimerVal, NULL)
+            ||  getitimer(ITIMER_REAL, &TimerVal)
+            ||  TimerVal.it_interval.tv_usec > 1000)
+        {
+            /*
+             * Try open /dev/rtc to set the irq rate to 1024 and
+             * turn periodic
+             */
+            Log(("RTTimerCreate: interval={%ld,%ld} trying to adjust /dev/rtc!\n", TimerVal.it_interval.tv_sec, TimerVal.it_interval.tv_usec));
+# ifdef RT_OS_LINUX
+            int fh = open("/dev/rtc", O_RDONLY);
+            if (fh >= 0)
+            {
+                if (    ioctl(fh, RTC_IRQP_SET, 1024) < 0
+                    ||  ioctl(fh, RTC_PIE_ON, 0) < 0)
+                    Log(("RTTimerCreate: couldn't configure rtc! errno=%d\n", errno));
+                ioctl(fh, F_SETFL, O_ASYNC);
+                ioctl(fh, F_SETOWN, getpid());
+                /* not so sure if closing it is a good idea... */
+                //close(fh);
+            }
+            else
+                Log(("RTTimerCreate: couldn't configure rtc! open failed with errno=%d\n", errno));
+# endif
+        }
+        /* disable it */
+        TimerVal.it_interval.tv_sec = 0;
+        TimerVal.it_interval.tv_usec = 0;
+        TimerVal.it_value = TimerVal.it_interval;
+        setitimer(ITIMER_REAL, &TimerVal, NULL);
+    }
+
+    /*
+     * Create a new timer.
+     */
+    int rc;
+    PRTTIMER pTimer = (PRTTIMER)RTMemAlloc(sizeof(*pTimer));
+    if (pTimer)
+    {
+        pTimer->u32Magic    = RTTIMER_MAGIC;
+        pTimer->fSuspended  = true;
+        pTimer->fDestroyed  = false;
+        pTimer->Thread      = NIL_RTTHREAD;
+        pTimer->Event       = NIL_RTSEMEVENT;
+        pTimer->pfnTimer    = pfnTimer;
+        pTimer->pvUser      = pvUser;
+        pTimer->u64NanoInterval = u64NanoInterval;
+        pTimer->u64NanoFirst = 0;
+        pTimer->iTick       = 0;
+        pTimer->iError      = 0;
+        rc = RTSemEventCreate(&pTimer->Event);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTThreadCreate(&pTimer->Thread, rttimerThread, pTimer, 0, RTTHREADTYPE_TIMER, RTTHREADFLAGS_WAITABLE, "Timer");
+            AssertRC(rc);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Wait for the timer thread to initialize it self.
+                 * This might take a little while...
+                 */
+                rc = RTThreadUserWait(pTimer->Thread, 45*1000);
+                AssertRC(rc);
+                if (RT_SUCCESS(rc))
+                {
+                    rc = RTThreadUserReset(pTimer->Thread); AssertRC(rc);
+                    rc = pTimer->iError;
+                    AssertRC(rc);
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTThreadYield(); /* <-- Horrible hack to make tstTimer work. (linux 2.6.12) */
+                        *ppTimer = pTimer;
+                        return VINF_SUCCESS;
+                    }
+                }
+
+                /* bail out */
+                ASMAtomicXchgU8(&pTimer->fDestroyed, true);
+                ASMAtomicXchgU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
+                RTThreadWait(pTimer->Thread, 45*1000, NULL);
+            }
+            RTSemEventDestroy(pTimer->Event);
+            pTimer->Event = NIL_RTSEMEVENT;
+        }
+        RTMemFree(pTimer);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+#else /* IPRT_WITH_POSIX_TIMERS */
+
+    /*
+     * Do the global init first.
+     */
+    int rc = RTOnce(&g_TimerOnce, rtTimerOnce, NULL);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Create a new timer structure.
+     */
+    LogFlow(("RTTimerCreateEx: u64NanoInterval=%llu fFlags=%lu\n", u64NanoInterval, fFlags));
+    PRTTIMER pTimer = (PRTTIMER)RTMemAlloc(sizeof(*pTimer));
+    if (pTimer)
+    {
+        /* Initialize timer structure. */
+        pTimer->u32Magic        = RTTIMER_MAGIC;
+        pTimer->fSuspended      = true;
+        pTimer->fDestroyed      = false;
+        pTimer->pfnTimer        = pfnTimer;
+        pTimer->pvUser          = pvUser;
+        pTimer->u64NanoInterval = u64NanoInterval;
+        pTimer->iTick           = 0;
+
+        /*
+         * Create a timer that deliver RT_TIMER_SIGNAL upon timer expiration.
+         */
+        struct sigevent SigEvt;
+        SigEvt.sigev_notify = SIGEV_SIGNAL;
+        SigEvt.sigev_signo  = RT_TIMER_SIGNAL;
+        SigEvt.sigev_value.sival_ptr = pTimer; /* sigev_value gets copied to siginfo. */
+        int err = timer_create(CLOCK_REALTIME, &SigEvt, &pTimer->NativeTimer);
+        if (!err)
+        {
+            /*
+             * Increment the timer count, do this behind the critsect to avoid races.
+             */
+            RTCritSectEnter(&g_TimerCritSect);
+
+            if (ASMAtomicIncU32(&g_cTimerInstances) != 1)
+            {
+                Assert(g_cTimerInstances > 1);
+                RTCritSectLeave(&g_TimerCritSect);
+
+                LogFlow(("RTTimerCreateEx: rc=%Rrc pTimer=%p (thread already running)\n", rc, pTimer));
+                *ppTimer = pTimer;
+                return VINF_SUCCESS;
+            }
+
+            /*
+             * Create the signal handling thread. It will wait for the signal
+             * and execute the timer functions.
+             */
+            rc = RTThreadCreate(&g_TimerThread, rttimerThread, NULL, 0, RTTHREADTYPE_TIMER, RTTHREADFLAGS_WAITABLE, "Timer");
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTThreadUserWait(g_TimerThread, 45*1000); /* this better not fail... */
+                if (RT_SUCCESS(rc))
+                {
+                    RTCritSectLeave(&g_TimerCritSect);
+
+                    LogFlow(("RTTimerCreateEx: rc=%Rrc pTimer=%p (thread already running)\n", rc, pTimer));
+                    *ppTimer = pTimer;
+                    return VINF_SUCCESS;
+                }
+                /* darn, what do we do here? */
+            }
+
+            /* bail out */
+            ASMAtomicDecU32(&g_cTimerInstances);
+            Assert(!g_cTimerInstances);
+
+            RTCritSectLeave(&g_TimerCritSect);
+
+            timer_delete(pTimer->NativeTimer);
+        }
+        else
+        {
+            rc = RTErrConvertFromErrno(err);
+            Log(("RTTimerCreateEx: err=%d (%Rrc)\n", err, rc));
+        }
+
+        RTMemFree(pTimer);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+#endif /* IPRT_WITH_POSIX_TIMERS */
+    return rc;
+}
+
+
+RTR3DECL(int) RTTimerDestroy(PRTTIMER pTimer)
+{
+    LogFlow(("RTTimerDestroy: pTimer=%p\n", pTimer));
+
+    /*
+     * Validate input.
+     */
+    /* NULL is ok. */
+    if (!pTimer)
+        return VINF_SUCCESS;
+    int rc = VINF_SUCCESS;
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+#ifdef IPRT_WITH_POSIX_TIMERS
+    AssertReturn(g_TimerThread != RTThreadSelf(), VERR_INTERNAL_ERROR);
+#else
+    AssertReturn(pTimer->Thread != RTThreadSelf(), VERR_INTERNAL_ERROR);
+#endif
+
+    /*
+     * Mark the semaphore as destroyed.
+     */
+    ASMAtomicWriteU8(&pTimer->fDestroyed, true);
+    ASMAtomicWriteU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
+
+#ifdef IPRT_WITH_POSIX_TIMERS
+    /*
+     * Suspend the timer if it's running.
+     */
+    if (!pTimer->fSuspended)
+    {
+        struct itimerspec TimerSpec;
+        TimerSpec.it_value.tv_sec     = 0;
+        TimerSpec.it_value.tv_nsec    = 0;
+        TimerSpec.it_interval.tv_sec  = 0;
+        TimerSpec.it_interval.tv_nsec = 0;
+        int err = timer_settime(pTimer->NativeTimer, 0, &TimerSpec, NULL); NOREF(err);
+        AssertMsg(!err, ("%d / %d\n", err, errno));
+    }
+#endif
+
+    /*
+     * Poke the thread and wait for it to finish.
+     * This is only done for the last timer when using posix timers.
+     */
+#ifdef IPRT_WITH_POSIX_TIMERS
+    RTTHREAD Thread = NIL_RTTHREAD;
+    RTCritSectEnter(&g_TimerCritSect);
+    if (ASMAtomicDecU32(&g_cTimerInstances) == 0)
+    {
+        Thread = g_TimerThread;
+        g_TimerThread = NIL_RTTHREAD;
+    }
+    RTCritSectLeave(&g_TimerCritSect);
+#else  /* IPRT_WITH_POSIX_TIMERS */
+    RTTHREAD Thread = pTimer->Thread;
+    rc = RTSemEventSignal(pTimer->Event);
+    AssertRC(rc);
+#endif /* IPRT_WITH_POSIX_TIMERS */
+    if (Thread != NIL_RTTHREAD)
+    {
+        /* Signal it so it gets out of the sigwait if it's stuck there... */
+        pthread_kill((pthread_t)RTThreadGetNative(Thread), RT_TIMER_SIGNAL);
+
+        /*
+         * Wait for the thread to complete.
+         */
+        rc = RTThreadWait(Thread, 30 * 1000, NULL);
+        AssertRC(rc);
+    }
+
+
+    /*
+     * Free up the resources associated with the timer.
+     */
+#ifdef IPRT_WITH_POSIX_TIMERS
+    timer_delete(pTimer->NativeTimer);
+#else
+    RTSemEventDestroy(pTimer->Event);
+    pTimer->Event = NIL_RTSEMEVENT;
+#endif /* !IPRT_WITH_POSIX_TIMERS */
+    if (RT_SUCCESS(rc))
+        RTMemFree(pTimer);
+    return rc;
+}
+
+
+RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+#ifndef IPRT_WITH_POSIX_TIMERS
+    AssertReturn(pTimer->Thread != RTThreadSelf(), VERR_INTERNAL_ERROR);
+#endif
+
+    /*
+     * Already running?
+     */
+    if (!ASMAtomicXchgU8(&pTimer->fSuspended, false))
+        return VERR_TIMER_ACTIVE;
+    LogFlow(("RTTimerStart: pTimer=%p u64First=%llu u64NanoInterval=%llu\n", pTimer, u64First, pTimer->u64NanoInterval));
+
+#ifndef IPRT_WITH_POSIX_TIMERS
+    /*
+     * Tell the thread to start servicing the timer.
+     * Wait for it to ACK the request to avoid reset races.
+     */
+    RTThreadUserReset(pTimer->Thread);
+    ASMAtomicUoWriteU64(&pTimer->u64NanoFirst, u64First);
+    ASMAtomicUoWriteU64(&pTimer->iTick, 0);
+    ASMAtomicWriteU8(&pTimer->fSuspended, false);
+    int rc = RTSemEventSignal(pTimer->Event);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTThreadUserWait(pTimer->Thread, 45*1000);
+        AssertRC(rc);
+        RTThreadUserReset(pTimer->Thread);
+    }
+    else
+        AssertRC(rc);
+
+#else /* IPRT_WITH_POSIX_TIMERS */
+    /*
+     * Start the timer.
+     */
+    struct itimerspec TimerSpec;
+    TimerSpec.it_value.tv_sec     = u64First / 1000000000; /* nanosec => sec */
+    TimerSpec.it_value.tv_nsec    = u64First ? u64First % 1000000000 : 10; /* 0 means disable, replace it with 10. */
+    TimerSpec.it_interval.tv_sec  = pTimer->u64NanoInterval / 1000000000;
+    TimerSpec.it_interval.tv_nsec = pTimer->u64NanoInterval % 1000000000;
+    int err = timer_settime(pTimer->NativeTimer, 0, &TimerSpec, NULL);
+    int rc = err == 0 ? VINF_SUCCESS : RTErrConvertFromErrno(errno);
+#endif /* IPRT_WITH_POSIX_TIMERS */
+
+    if (RT_FAILURE(rc))
+        ASMAtomicXchgU8(&pTimer->fSuspended, false);
+    return rc;
+}
+
+
+RTDECL(int) RTTimerStop(PRTTIMER pTimer)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+
+    /*
+     * Already running?
+     */
+    if (ASMAtomicXchgU8(&pTimer->fSuspended, true))
+        return VERR_TIMER_SUSPENDED;
+    LogFlow(("RTTimerStop: pTimer=%p\n", pTimer));
+
+#ifndef IPRT_WITH_POSIX_TIMERS
+    /*
+     * Tell the thread to stop servicing the timer.
+     */
+    RTThreadUserReset(pTimer->Thread);
+    ASMAtomicXchgU8(&pTimer->fSuspended, true);
+    int rc = VINF_SUCCESS;
+    if (RTThreadSelf() != pTimer->Thread)
+    {
+        pthread_kill((pthread_t)RTThreadGetNative(pTimer->Thread), RT_TIMER_SIGNAL);
+        rc = RTThreadUserWait(pTimer->Thread, 45*1000);
+        AssertRC(rc);
+        RTThreadUserReset(pTimer->Thread);
+    }
+
+#else /* IPRT_WITH_POSIX_TIMERS */
+    /*
+     * Stop the timer.
+     */
+    struct itimerspec TimerSpec;
+    TimerSpec.it_value.tv_sec     = 0;
+    TimerSpec.it_value.tv_nsec    = 0;
+    TimerSpec.it_interval.tv_sec  = 0;
+    TimerSpec.it_interval.tv_nsec = 0;
+    int err = timer_settime(pTimer->NativeTimer, 0, &TimerSpec, NULL);
+    int rc = err == 0 ? VINF_SUCCESS : RTErrConvertFromErrno(errno);
+#endif /* IPRT_WITH_POSIX_TIMERS */
+
+    return rc;
+}
+
+
+RTDECL(int) RTTimerChangeInterval(PRTTIMER pTimer, uint64_t u64NanoInterval)
+{
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+    NOREF(u64NanoInterval);
+    return VERR_NOT_SUPPORTED;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/tls-posix.cpp b/src/VBox/Runtime/r3/posix/tls-posix.cpp
new file mode 100644
index 00000000..22ef28ab
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/tls-posix.cpp
@@ -0,0 +1,119 @@
+/* $Id: tls-posix.cpp $ */
+/** @file
+ * IPRT - Thread Local Storage (TLS), POSIX.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <errno.h>
+#include <pthread.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+
+AssertCompile(sizeof(pthread_key_t) <= sizeof(RTTLS));
+
+
+RTR3DECL(RTTLS) RTTlsAlloc(void)
+{
+    pthread_key_t iTls = (pthread_key_t)NIL_RTTLS;
+    int rc = pthread_key_create(&iTls, NULL);
+    if (!rc)
+    {
+        Assert(iTls != (pthread_key_t)NIL_RTTLS);
+        return iTls;
+    }
+    return NIL_RTTLS;
+}
+
+
+RTR3DECL(int) RTTlsAllocEx(PRTTLS piTls, PFNRTTLSDTOR pfnDestructor)
+{
+    pthread_key_t iTls = (pthread_key_t)NIL_RTTLS;
+#if defined(__GNUC__) && defined(RT_ARCH_X86)
+    int rc = pthread_key_create(&iTls, (void (*)(void*))pfnDestructor);
+#else
+    int rc = pthread_key_create(&iTls, pfnDestructor);
+#endif
+    if (!rc)
+    {
+        *piTls = iTls;
+        Assert((pthread_key_t)*piTls == iTls);
+        Assert(*piTls != NIL_RTTLS);
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(rc);
+}
+
+
+RTR3DECL(int) RTTlsFree(RTTLS iTls)
+{
+    if (iTls == NIL_RTTLS)
+        return VINF_SUCCESS;
+    int rc = pthread_key_delete(iTls);
+    if (!rc)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(rc);
+}
+
+
+RTR3DECL(void *) RTTlsGet(RTTLS iTls)
+{
+    return pthread_getspecific(iTls);
+}
+
+
+RTR3DECL(int) RTTlsGetEx(RTTLS iTls, void **ppvValue)
+{
+    if (RT_UNLIKELY(iTls == NIL_RTTLS))
+        return VERR_INVALID_PARAMETER;
+    *ppvValue = pthread_getspecific(iTls);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTlsSet(RTTLS iTls, void *pvValue)
+{
+    int rc = pthread_setspecific(iTls, pvValue);
+    if (RT_UNLIKELY(rc != 0))
+        return RTErrConvertFromErrno(rc);
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/posix/utf8-posix.cpp b/src/VBox/Runtime/r3/posix/utf8-posix.cpp
new file mode 100644
index 00000000..5f4c947e
--- /dev/null
+++ b/src/VBox/Runtime/r3/posix/utf8-posix.cpp
@@ -0,0 +1,709 @@
+/* $Id: utf8-posix.cpp $ */
+/** @file
+ * IPRT - UTF-8 helpers, POSIX.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/string.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+
+#include <errno.h>
+#include <locale.h>
+#ifdef RT_OS_DARWIN
+# include <stdlib.h>
+#endif
+
+/* iconv prototype changed with 165+ (thanks to PSARC/2010/160 Bugster 7037400) */
+#if defined(RT_OS_SOLARIS)
+# if !defined(_XPG6)
+#  define IPRT_XPG6_TMP_DEF
+#  define _XPG6
+# endif
+# if defined(__USE_LEGACY_PROTOTYPES__)
+#  define IPRT_LEGACY_PROTO_TMP_DEF
+#  undef __USE_LEGACY_PROTOTYPES__
+# endif
+#endif /* RT_OS_SOLARIS */
+
+# include <iconv.h>
+
+#if defined(RT_OS_SOLARIS)
+# if defined(IPRT_XPG6_TMP_DEF)
+#  undef _XPG6
+#  undef IPRT_XPG6_TMP_DEF
+# endif
+# if defined(IPRT_LEGACY_PROTO_TMP_DEF)
+#  define __USE_LEGACY_PROTOTYPES__
+#  undef IPRT_LEGACY_PROTO_TMP_DEF
+# endif
+#endif /* RT_OS_SOLARIS */
+
+#include <wctype.h>
+
+#include <langinfo.h>
+
+#include "internal/alignmentchecks.h"
+#include "internal/string.h"
+#ifdef RT_WITH_ICONV_CACHE
+# include "internal/thread.h"
+AssertCompile(sizeof(iconv_t) <= sizeof(void *));
+#endif
+
+
+/* There are different opinions about the constness of the input buffer. */
+#if defined(RT_OS_LINUX) || defined(RT_OS_HAIKU) || defined(RT_OS_SOLARIS) \
+  || (defined(RT_OS_DARWIN) && defined(_DARWIN_FEATURE_UNIX_CONFORMANCE))
+# define NON_CONST_ICONV_INPUT
+#endif
+#ifdef RT_OS_FREEBSD
+# include <sys/param.h>
+# if __FreeBSD_version >= 1002000 /* Changed around 10.2.2 (https://svnweb.freebsd.org/base?view=revision&revision=281550) */
+#  define NON_CONST_ICONV_INPUT
+# else
+# error __FreeBSD_version__
+# endif
+#endif
+#ifdef RT_OS_NETBSD
+/* iconv constness was changed on 2019-10-24, shortly after 9.99.17 */
+# include <sys/param.h>
+# if __NetBSD_Prereq__(9,99,18)
+#  define NON_CONST_ICONV_INPUT
+# endif
+#endif
+
+
+/**
+ * Gets the codeset of the current locale (LC_CTYPE).
+ *
+ * @returns Pointer to read-only string with the codeset name.
+ */
+DECLHIDDEN(const char *) rtStrGetLocaleCodeset(void)
+{
+#ifdef RT_OS_DARWIN
+    /*
+     * @bugref{10153}: If no locale specified in the environment (typically the
+     *      case when launched via Finder, LaunchPad or similar) default to UTF-8.
+     */
+    static int8_t volatile s_fIsUtf8 = -1;
+    int8_t fIsUtf8 = s_fIsUtf8;
+    if (fIsUtf8)
+    {
+        if (fIsUtf8 == true)
+            return "UTF-8";
+
+        /* Initialize: */
+        fIsUtf8 = true;
+        static const char * const s_papszVariables[] = { "LC_ALL", "LC_CTYPE", "LANG" };
+        for (size_t i = 0; i < RT_ELEMENTS(s_papszVariables); i++)
+        {
+            const char *pszValue = getenv(s_papszVariables[i]);
+            if (pszValue && *pszValue)
+            {
+                fIsUtf8 = false;
+                break;
+            }
+        }
+        s_fIsUtf8 = fIsUtf8;
+        if (fIsUtf8 == true)
+            return "UTF-8";
+    }
+#endif
+    return nl_langinfo(CODESET);
+}
+
+
+/**
+ * Checks if the codeset specified by current locale (LC_CTYPE) is UTF-8.
+ *
+ * @returns true if UTF-8, false if not.
+ */
+DECLHIDDEN(bool) rtStrIsLocaleCodesetUtf8(void)
+{
+    return rtStrIsCodesetUtf8(rtStrGetLocaleCodeset());
+}
+
+
+/**
+ * Checks if @a pszCodeset specified UTF-8.
+ *
+ * @returns true if UTF-8, false if not.
+ * @param   pszCodeset      Codeset to test.
+ */
+DECLHIDDEN(bool) rtStrIsCodesetUtf8(const char *pszCodeset)
+{
+    if (pszCodeset)
+    {
+        /* Skip leading spaces just in case: */
+        while (RT_C_IS_SPACE(*pszCodeset))
+            pszCodeset++;
+
+        /* If prefixed by 'ISO-10646/' skip that (iconv access this, dunno about
+           LC_CTYPE et al., but play it safe): */
+        if (   strncmp(pszCodeset, RT_STR_TUPLE("ISO-10646/")) == 0
+            || strncmp(pszCodeset, RT_STR_TUPLE("iso-10646/")) == 0)
+            pszCodeset += sizeof("ISO-10646/") - 1;
+
+        /* Match 'utf': */
+        if (   (pszCodeset[0] == 'u' || pszCodeset[0] == 'U')
+            && (pszCodeset[1] == 't' || pszCodeset[1] == 'T')
+            && (pszCodeset[2] == 'f' || pszCodeset[2] == 'F'))
+        {
+            pszCodeset += 3;
+
+            /* Treat the dash as optional: */
+            if (*pszCodeset == '-')
+                pszCodeset++;
+
+            /* Match '8': */
+            if (*pszCodeset == '8')
+            {
+                do
+                    pszCodeset++;
+                while (RT_C_IS_SPACE(*pszCodeset));
+
+                /* We ignore modifiers here (e.g. "[be_BY.]utf8@latin"). */
+                if (!*pszCodeset || *pszCodeset == '@')
+                    return true;
+            }
+        }
+    }
+    return false;
+}
+
+
+
+#ifdef RT_WITH_ICONV_CACHE
+
+/**
+ * Initializes the iconv handle cache associated with a thread.
+ *
+ * @param   pThread             The thread in question.
+ */
+DECLHIDDEN(void) rtStrIconvCacheInit(PRTTHREADINT pThread)
+{
+    for (size_t i = 0; i < RT_ELEMENTS(pThread->ahIconvs); i++)
+        pThread->ahIconvs[i] = (iconv_t)-1;
+}
+
+/**
+ * Destroys the iconv handle cache associated with a thread.
+ *
+ * @param   pThread             The thread in question.
+ */
+DECLHIDDEN(void) rtStrIconvCacheDestroy(PRTTHREADINT pThread)
+{
+    for (size_t i = 0; i < RT_ELEMENTS(pThread->ahIconvs); i++)
+    {
+        iconv_t hIconv = (iconv_t)pThread->ahIconvs[i];
+        pThread->ahIconvs[i] = (iconv_t)-1;
+        if (hIconv != (iconv_t)-1)
+            iconv_close(hIconv);
+    }
+}
+
+
+/**
+ * Converts a string from one charset to another.
+ *
+ * @returns iprt status code.
+ * @param   pvInput         Pointer to intput string.
+ * @param   cbInput         Size (in bytes) of input string. Excludes any terminators.
+ * @param   pszInputCS      Codeset of the input string.
+ * @param   ppvOutput       Pointer to pointer to output buffer if cbOutput > 0.
+ *                          If cbOutput is 0 this is where the pointer to the allocated
+ *                          buffer is stored.
+ * @param   cbOutput        Size of the passed in buffer.
+ * @param   pszOutputCS     Codeset of the input string.
+ * @param   cFactor         Input vs. output size factor.
+ * @param   phIconv         Pointer to the cache entry.
+ */
+static int rtstrConvertCached(const void *pvInput, size_t cbInput, const char *pszInputCS,
+                              void **ppvOutput, size_t cbOutput, const char *pszOutputCS,
+                              unsigned cFactor, iconv_t *phIconv)
+{
+    /*
+     * Allocate buffer
+     */
+    bool    fUcs2Term;
+    void   *pvOutput;
+    size_t  cbOutput2;
+    if (!cbOutput)
+    {
+        cbOutput2 = cbInput * cFactor;
+        pvOutput = RTMemTmpAlloc(cbOutput2 + sizeof(RTUTF16));
+        if (!pvOutput)
+            return VERR_NO_TMP_MEMORY;
+        fUcs2Term = true;
+    }
+    else
+    {
+        pvOutput = *ppvOutput;
+        fUcs2Term = !strcmp(pszOutputCS, "UCS-2")
+                 || !strcmp(pszOutputCS, "UTF-16")
+                 || !strcmp(pszOutputCS, "ucs-2")
+                 || !strcmp(pszOutputCS, "utf-16");
+        cbOutput2 = cbOutput - (fUcs2Term ? sizeof(RTUTF16) : 1);
+        if (cbOutput2 > cbOutput)
+            return VERR_BUFFER_OVERFLOW;
+    }
+
+    /*
+     * Use a loop here to retry with bigger buffers.
+     */
+    for (unsigned cTries = 10; cTries > 0; cTries--)
+    {
+        /*
+         * Create conversion object if necessary.
+         */
+        iconv_t hIconv = (iconv_t)*phIconv;
+        if (hIconv == (iconv_t)-1)
+        {
+#if defined(RT_OS_SOLARIS) || defined(RT_OS_NETBSD) || /* @bugref{10153}: Default to UTF-8: */ defined(RT_OS_DARWIN)
+            /* Some systems don't grok empty codeset strings, so help them find the current codeset. */
+            if (!*pszInputCS)
+                pszInputCS = rtStrGetLocaleCodeset();
+            if (!*pszOutputCS)
+                pszOutputCS = rtStrGetLocaleCodeset();
+#endif
+            IPRT_ALIGNMENT_CHECKS_DISABLE(); /* glibc causes trouble */
+            *phIconv = hIconv = iconv_open(pszOutputCS, pszInputCS);
+            IPRT_ALIGNMENT_CHECKS_ENABLE();
+        }
+        if (hIconv != (iconv_t)-1)
+        {
+            /*
+             * Do the conversion.
+             */
+            size_t      cbInLeft = cbInput;
+            size_t      cbOutLeft = cbOutput2;
+            const void *pvInputLeft = pvInput;
+            void       *pvOutputLeft = pvOutput;
+            size_t      cchNonRev;
+#ifdef NON_CONST_ICONV_INPUT
+            cchNonRev = iconv(hIconv, (char **)&pvInputLeft, &cbInLeft, (char **)&pvOutputLeft, &cbOutLeft);
+#else
+            cchNonRev = iconv(hIconv, (const char **)&pvInputLeft, &cbInLeft, (char **)&pvOutputLeft, &cbOutLeft);
+#endif
+            if (cchNonRev != (size_t)-1)
+            {
+                if (!cbInLeft)
+                {
+                    /*
+                     * We're done, just add the terminator and return.
+                     * (Two terminators to support UCS-2 output, too.)
+                     */
+                    ((char *)pvOutputLeft)[0] = '\0';
+                    if (fUcs2Term)
+                        ((char *)pvOutputLeft)[1] = '\0';
+                    *ppvOutput = pvOutput;
+                    if (cchNonRev == 0)
+                        return VINF_SUCCESS;
+                    return VWRN_NO_TRANSLATION;
+                }
+                errno = E2BIG;
+            }
+
+            /*
+             * If we failed because of output buffer space we'll
+             * increase the output buffer size and retry.
+             */
+            if (errno == E2BIG)
+            {
+                if (!cbOutput)
+                {
+                    RTMemTmpFree(pvOutput);
+                    cbOutput2 *= 2;
+                    pvOutput = RTMemTmpAlloc(cbOutput2 + sizeof(RTUTF16));
+                    if (!pvOutput)
+                        return VERR_NO_TMP_MEMORY;
+                    continue;
+                }
+                return VERR_BUFFER_OVERFLOW;
+            }
+
+            /*
+             * Close the handle on all other errors to make sure we won't carry
+             * any bad state with us.
+             */
+            *phIconv = (iconv_t)-1;
+            iconv_close(hIconv);
+        }
+        break;
+    }
+
+    /* failure */
+    if (!cbOutput)
+        RTMemTmpFree(pvOutput);
+    return VERR_NO_TRANSLATION;
+}
+
+#endif /* RT_WITH_ICONV_CACHE */
+
+/**
+ * Converts a string from one charset to another without using the handle cache.
+ *
+ * @returns IPRT status code.
+ *
+ * @param   pvInput         Pointer to intput string.
+ * @param   cbInput         Size (in bytes) of input string. Excludes any terminators.
+ * @param   pszInputCS      Codeset of the input string.
+ * @param   ppvOutput       Pointer to pointer to output buffer if cbOutput > 0.
+ *                          If cbOutput is 0 this is where the pointer to the allocated
+ *                          buffer is stored.
+ * @param   cbOutput        Size of the passed in buffer.
+ * @param   pszOutputCS     Codeset of the input string.
+ * @param   cFactor         Input vs. output size factor.
+ */
+static int rtStrConvertUncached(const void *pvInput, size_t cbInput, const char *pszInputCS,
+                                void **ppvOutput, size_t cbOutput, const char *pszOutputCS,
+                                unsigned cFactor)
+{
+    /*
+     * Allocate buffer
+     */
+    bool    fUcs2Term;
+    void   *pvOutput;
+    size_t  cbOutput2;
+    if (!cbOutput)
+    {
+        cbOutput2 = cbInput * cFactor;
+        pvOutput = RTMemTmpAlloc(cbOutput2 + sizeof(RTUTF16));
+        if (!pvOutput)
+            return VERR_NO_TMP_MEMORY;
+        fUcs2Term = true;
+    }
+    else
+    {
+        pvOutput = *ppvOutput;
+        fUcs2Term = !strcmp(pszOutputCS, "UCS-2");
+        cbOutput2 = cbOutput - (fUcs2Term ? sizeof(RTUTF16) : 1);
+        if (cbOutput2 > cbOutput)
+            return VERR_BUFFER_OVERFLOW;
+    }
+
+    /*
+     * Use a loop here to retry with bigger buffers.
+     */
+    for (unsigned cTries = 10; cTries > 0; cTries--)
+    {
+        /*
+         * Create conversion object.
+         */
+#if defined(RT_OS_SOLARIS) || defined(RT_OS_NETBSD) || /* @bugref{10153}: Default to UTF-8: */ defined(RT_OS_DARWIN)
+        /* Some systems don't grok empty codeset strings, so help them find the current codeset. */
+        if (!*pszInputCS)
+            pszInputCS = rtStrGetLocaleCodeset();
+        if (!*pszOutputCS)
+            pszOutputCS = rtStrGetLocaleCodeset();
+#endif
+        IPRT_ALIGNMENT_CHECKS_DISABLE(); /* glibc causes trouble */
+        iconv_t icHandle = iconv_open(pszOutputCS, pszInputCS);
+        IPRT_ALIGNMENT_CHECKS_ENABLE();
+        if (icHandle != (iconv_t)-1)
+        {
+            /*
+             * Do the conversion.
+             */
+            size_t      cbInLeft = cbInput;
+            size_t      cbOutLeft = cbOutput2;
+            const void *pvInputLeft = pvInput;
+            void       *pvOutputLeft = pvOutput;
+            size_t      cchNonRev;
+#ifdef NON_CONST_ICONV_INPUT
+            cchNonRev = iconv(icHandle, (char **)&pvInputLeft, &cbInLeft, (char **)&pvOutputLeft, &cbOutLeft);
+#else
+            cchNonRev = iconv(icHandle, (const char **)&pvInputLeft, &cbInLeft, (char **)&pvOutputLeft, &cbOutLeft);
+#endif
+            if (cchNonRev != (size_t)-1)
+            {
+                if (!cbInLeft)
+                {
+                    /*
+                     * We're done, just add the terminator and return.
+                     * (Two terminators to support UCS-2 output, too.)
+                     */
+                    iconv_close(icHandle);
+                    ((char *)pvOutputLeft)[0] = '\0';
+                    if (fUcs2Term)
+                        ((char *)pvOutputLeft)[1] = '\0';
+                    *ppvOutput = pvOutput;
+                    if (cchNonRev == 0)
+                        return VINF_SUCCESS;
+                    return VWRN_NO_TRANSLATION;
+                }
+                errno = E2BIG;
+            }
+            iconv_close(icHandle);
+
+            /*
+             * If we failed because of output buffer space we'll
+             * increase the output buffer size and retry.
+             */
+            if (errno == E2BIG)
+            {
+                if (!cbOutput)
+                {
+                    RTMemTmpFree(pvOutput);
+                    cbOutput2 *= 2;
+                    pvOutput = RTMemTmpAlloc(cbOutput2 + sizeof(RTUTF16));
+                    if (!pvOutput)
+                        return VERR_NO_TMP_MEMORY;
+                    continue;
+                }
+                return VERR_BUFFER_OVERFLOW;
+            }
+        }
+        break;
+    }
+
+    /* failure */
+    if (!cbOutput)
+        RTMemTmpFree(pvOutput);
+    return VERR_NO_TRANSLATION;
+}
+
+
+/**
+ * Wrapper that selects rtStrConvertCached or rtStrConvertUncached.
+ *
+ * @returns IPRT status code.
+ *
+ * @param   pszInput        Pointer to intput string.
+ * @param   cchInput        Size (in bytes) of input string. Excludes any
+ *                          terminators.
+ * @param   pszInputCS      Codeset of the input string.
+ * @param   ppszOutput      Pointer to pointer to output buffer if cbOutput > 0.
+ *                          If cbOutput is 0 this is where the pointer to the
+ *                          allocated buffer is stored.
+ * @param   cbOutput        Size of the passed in buffer.
+ * @param   pszOutputCS     Codeset of the input string.
+ * @param   cFactor         Input vs. output size factor.
+ * @param   enmCacheIdx     The iconv cache index.
+ */
+DECLINLINE(int) rtStrConvertWrapper(const char *pchInput, size_t cchInput, const char *pszInputCS,
+                                    char **ppszOutput, size_t cbOutput, const char *pszOutputCS,
+                                    unsigned cFactor, RTSTRICONV enmCacheIdx)
+{
+#ifdef RT_WITH_ICONV_CACHE
+    RTTHREAD hSelf = RTThreadSelf();
+    if (hSelf != NIL_RTTHREAD)
+    {
+        PRTTHREADINT pThread = rtThreadGet(hSelf);
+        if (pThread)
+        {
+            if ((pThread->fIntFlags & (RTTHREADINT_FLAGS_ALIEN | RTTHREADINT_FLAGS_MAIN)) != RTTHREADINT_FLAGS_ALIEN)
+            {
+                int rc = rtstrConvertCached(pchInput, cchInput, pszInputCS,
+                                            (void **)ppszOutput, cbOutput, pszOutputCS,
+                                            cFactor, (iconv_t *)&pThread->ahIconvs[enmCacheIdx]);
+                rtThreadRelease(pThread);
+                return rc;
+            }
+            rtThreadRelease(pThread);
+        }
+    }
+#endif
+    return rtStrConvertUncached(pchInput, cchInput, pszInputCS,
+                                (void **)ppszOutput, cbOutput, pszOutputCS,
+                                cFactor);
+}
+
+
+/**
+ * Internal API for use by the path conversion code.
+ *
+ * @returns IPRT status code.
+ *
+ * @param   pszInput        Pointer to intput string.
+ * @param   cchInput        Size (in bytes) of input string. Excludes any
+ *                          terminators.
+ * @param   pszInputCS      Codeset of the input string.
+ * @param   ppszOutput      Pointer to pointer to output buffer if cbOutput > 0.
+ *                          If cbOutput is 0 this is where the pointer to the
+ *                          allocated buffer is stored.
+ * @param   cbOutput        Size of the passed in buffer.
+ * @param   pszOutputCS     Codeset of the input string.
+ * @param   cFactor         Input vs. output size factor.
+ * @param   enmCacheIdx     The iconv cache index.
+ */
+DECLHIDDEN(int) rtStrConvert(const char *pchInput, size_t cchInput, const char *pszInputCS,
+                             char **ppszOutput, size_t cbOutput, const char *pszOutputCS,
+                             unsigned cFactor, RTSTRICONV enmCacheIdx)
+{
+    Assert(enmCacheIdx >= 0 && enmCacheIdx < RTSTRICONV_END);
+    return rtStrConvertWrapper(pchInput, cchInput, pszInputCS,
+                               ppszOutput, cbOutput, pszOutputCS,
+                               cFactor, enmCacheIdx);
+}
+
+
+/**
+ * Initializes a local conversion cache for use with rtStrLocalCacheConvert.
+ *
+ * Call rtStrLocalCacheDelete when done.
+ */
+DECLHIDDEN(void) rtStrLocalCacheInit(void **ppvTmpCache)
+{
+    *ppvTmpCache = (iconv_t)-1;
+}
+
+
+/**
+ * Cleans up a local conversion cache.
+ */
+DECLHIDDEN(void) rtStrLocalCacheDelete(void **ppvTmpCache)
+{
+#ifdef RT_WITH_ICONV_CACHE
+    iconv_t icHandle = (iconv_t)*ppvTmpCache;
+    if (icHandle != (iconv_t)-1)
+        iconv_close(icHandle);
+#endif
+    *ppvTmpCache = (iconv_t)-1;
+}
+
+
+/**
+ * Internal API for use by the process creation conversion code.
+ *
+ * @returns IPRT status code.
+ *
+ * @param   pszInput        Pointer to intput string.
+ * @param   cchInput        Size (in bytes) of input string. Excludes any
+ *                          terminators.
+ * @param   pszInputCS      Codeset of the input string.
+ * @param   ppszOutput      Pointer to pointer to output buffer if cbOutput > 0.
+ *                          If cbOutput is 0 this is where the pointer to the
+ *                          allocated buffer is stored.
+ * @param   cbOutput        Size of the passed in buffer.
+ * @param   pszOutputCS     Codeset of the input string.
+ * @param   ppvTmpCache     Pointer to local temporary cache.  Must be
+ *                          initialized by calling rtStrLocalCacheInit and
+ *                          cleaned up afterwards by rtStrLocalCacheDelete.
+ *                          Optional.
+ */
+DECLHIDDEN(int) rtStrLocalCacheConvert(const char *pchInput, size_t cchInput, const char *pszInputCS,
+                                       char **ppszOutput, size_t cbOutput, const char *pszOutputCS,
+                                       void **ppvTmpCache)
+{
+#ifdef RT_WITH_ICONV_CACHE
+    if (ppvTmpCache)
+        return rtstrConvertCached(pchInput, cchInput, pszInputCS, (void **)ppszOutput, cbOutput, pszOutputCS,
+                                  1 /*cFactor*/, (iconv_t *)ppvTmpCache);
+#else
+    RT_NOREF(ppvTmpCache);
+#endif
+
+    return rtStrConvertUncached(pchInput, cchInput, pszInputCS, (void **)ppszOutput, cbOutput, pszOutputCS, 1 /*cFactor*/);
+}
+
+
+RTR3DECL(int)  RTStrUtf8ToCurrentCPTag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    Assert(ppszString);
+    Assert(pszString);
+    *ppszString = NULL;
+
+    /*
+     * Assume result string length is not longer than UTF-8 string.
+     */
+    size_t cch = strlen(pszString);
+    if (cch <= 0)
+    {
+        /* zero length string passed. */
+        *ppszString = (char *)RTMemTmpAllocZTag(sizeof(char), pszTag);
+        if (*ppszString)
+            return VINF_SUCCESS;
+        return VERR_NO_TMP_MEMORY;
+    }
+    return rtStrConvertWrapper(pszString, cch, "UTF-8", ppszString, 0, "", 1, RTSTRICONV_UTF8_TO_LOCALE);
+}
+
+
+RTR3DECL(int)  RTStrUtf8ToCurrentCPExTag(char **ppszString, const char *pszString, size_t cchString, const char *pszTag)
+{
+    Assert(ppszString);
+    Assert(pszString);
+    *ppszString = NULL;
+
+    /*
+     * Assume result string length is not longer than UTF-8 string.
+     */
+    cchString = RTStrNLen(pszString, cchString);
+    if (cchString < 1)
+    {
+        /* zero length string passed. */
+        *ppszString = (char *)RTMemTmpAllocZTag(sizeof(char), pszTag);
+        if (*ppszString)
+            return VINF_SUCCESS;
+        return VERR_NO_TMP_MEMORY;
+    }
+    return rtStrConvertWrapper(pszString, cchString, "UTF-8", ppszString, 0, "", 1, RTSTRICONV_UTF8_TO_LOCALE);
+}
+
+
+RTR3DECL(int)  RTStrCurrentCPToUtf8Tag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    Assert(ppszString);
+    Assert(pszString);
+    *ppszString = NULL;
+
+    /*
+     * Attempt with UTF-8 length of 2x the native length.
+     */
+    size_t cch = strlen(pszString);
+    if (cch <= 0)
+    {
+        /* zero length string passed. */
+        *ppszString = (char *)RTMemTmpAllocZTag(sizeof(char), pszTag);
+        if (*ppszString)
+            return VINF_SUCCESS;
+        return VERR_NO_TMP_MEMORY;
+    }
+    return rtStrConvertWrapper(pszString, cch, "", ppszString, 0, "UTF-8", 2, RTSTRICONV_LOCALE_TO_UTF8);
+}
+
+
+RTR3DECL(int)  RTStrConsoleCPToUtf8Tag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    return RTStrCurrentCPToUtf8Tag(ppszString, pszString, pszTag);
+}
diff --git a/src/VBox/Runtime/r3/process-data.cpp b/src/VBox/Runtime/r3/process-data.cpp
new file mode 100644
index 00000000..1255d781
--- /dev/null
+++ b/src/VBox/Runtime/r3/process-data.cpp
@@ -0,0 +1,67 @@
+/* $Id: process-data.cpp $ */
+/** @file
+ * IPRT - Process Data Ring-3.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include "internal/process.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * The process identifier of the running process.
+ */
+DECL_HIDDEN_DATA(RTPROCESS)         g_ProcessSelf = NIL_RTPROCESS;
+
+/**
+ * The current process priority.
+ */
+DECL_HIDDEN_DATA(RTPROCPRIORITY)    g_enmProcessPriority = RTPROCPRIORITY_DEFAULT;
+
+/** The process path.
+ * This is used by RTPathExecDir and RTProcGetExecutablePath and set by rtProcInitName. */
+DECL_HIDDEN_DATA(char)              g_szrtProcExePath[RTPATH_MAX];
+/** The length of g_szrtProcExePath. */
+DECL_HIDDEN_DATA(size_t)            g_cchrtProcExePath;
+/** The offset of the process name into g_szrtProcExePath. */
+DECL_HIDDEN_DATA(size_t)            g_offrtProcName;
+/** The length of directory path component of g_szrtProcExePath. */
+DECL_HIDDEN_DATA(size_t)            g_cchrtProcExeDir;
+
diff --git a/src/VBox/Runtime/r3/process.cpp b/src/VBox/Runtime/r3/process.cpp
new file mode 100644
index 00000000..f9d1ecf2
--- /dev/null
+++ b/src/VBox/Runtime/r3/process.cpp
@@ -0,0 +1,135 @@
+/* $Id: process.cpp $ */
+/** @file
+ * IPRT - Process, Common.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/process.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include "internal/process.h"
+#include "internal/thread.h"
+
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/windows.h>
+#else
+# include <unistd.h>
+#endif
+
+
+/**
+ * Get the identifier for the current process.
+ *
+ * @returns Process identifier.
+ */
+RTDECL(RTPROCESS) RTProcSelf(void)
+{
+    RTPROCESS Self = g_ProcessSelf;
+    if (Self != NIL_RTPROCESS)
+        return Self;
+
+    /* lazy init. */
+#ifdef _MSC_VER
+    Self = GetCurrentProcessId(); /* since NT 3.1, not 3.51+ as listed on geoffchappell.com */
+#else
+    Self = getpid();
+#endif
+    g_ProcessSelf = Self;
+    return Self;
+}
+
+
+/**
+ * Attempts to alter the priority of the current process.
+ *
+ * @returns iprt status code.
+ * @param   enmPriority     The new priority.
+ */
+RTR3DECL(int) RTProcSetPriority(RTPROCPRIORITY enmPriority)
+{
+    if (enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST)
+        return rtThreadDoSetProcPriority(enmPriority);
+    AssertMsgFailed(("enmPriority=%d\n", enmPriority));
+    return VERR_INVALID_PARAMETER;
+}
+
+
+/**
+ * Gets the current priority of this process.
+ *
+ * @returns The priority (see RTPROCPRIORITY).
+ */
+RTR3DECL(RTPROCPRIORITY) RTProcGetPriority(void)
+{
+    return g_enmProcessPriority;
+}
+
+
+RTR3DECL(char *) RTProcGetExecutablePath(char *pszExecPath, size_t cbExecPath)
+{
+    if (RT_UNLIKELY(g_szrtProcExePath[0] == '\0'))
+        return NULL;
+
+    /*
+     * Calc the length and check if there is space before copying.
+     */
+    size_t cch = g_cchrtProcExePath;
+    if (cch < cbExecPath)
+    {
+        memcpy(pszExecPath, g_szrtProcExePath, cch);
+        pszExecPath[cch] = '\0';
+        return pszExecPath;
+    }
+
+    AssertMsgFailed(("Buffer too small (%zu <= %zu)\n", cbExecPath, cch));
+    return NULL;
+}
+
+
+RTR3DECL(const char *) RTProcExecutablePath(void)
+{
+    return g_szrtProcExePath;
+}
+
+
+RTR3DECL(const char *) RTProcShortName(void)
+{
+    return &g_szrtProcExePath[g_offrtProcName];
+}
+
diff --git a/src/VBox/Runtime/r3/socket.cpp b/src/VBox/Runtime/r3/socket.cpp
new file mode 100644
index 00000000..4acfe73e
--- /dev/null
+++ b/src/VBox/Runtime/r3/socket.cpp
@@ -0,0 +1,3186 @@
+/* $Id: socket.cpp $ */
+/** @file
+ * IPRT - Network Sockets.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/winsock2.h>
+# include <iprt/win/ws2tcpip.h>
+#else /* !RT_OS_WINDOWS */
+# include <errno.h>
+# include <sys/select.h>
+# include <sys/stat.h>
+# include <sys/socket.h>
+# include <netinet/in.h>
+# include <netinet/tcp.h>
+# include <arpa/inet.h>
+# ifdef IPRT_WITH_TCPIP_V6
+#  include <netinet6/in6.h>
+# endif
+# include <sys/un.h>
+# include <netdb.h>
+# include <unistd.h>
+# include <fcntl.h>
+# include <sys/uio.h>
+# ifndef AF_LOCAL
+#   define AF_LOCAL AF_UNIX
+# endif
+#endif /* !RT_OS_WINDOWS */
+#include <limits.h>
+
+#include "internal/iprt.h"
+#include <iprt/socket.h>
+
+#include <iprt/alloca.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/mempool.h>
+#include <iprt/poll.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include <iprt/mem.h>
+#include <iprt/sg.h>
+#include <iprt/log.h>
+
+#include "internal/magics.h"
+#include "internal/socket.h"
+#include "internal/string.h"
+#ifdef RT_OS_WINDOWS
+# include "win/internal-r3-win.h"
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/* non-standard linux stuff (it seems). */
+#ifndef MSG_NOSIGNAL
+# define MSG_NOSIGNAL           0
+#endif
+
+/* Windows has different names for SHUT_XXX. */
+#ifndef SHUT_RDWR
+# ifdef SD_BOTH
+#  define SHUT_RDWR             SD_BOTH
+# else
+#  define SHUT_RDWR             2
+# endif
+#endif
+#ifndef SHUT_WR
+# ifdef SD_SEND
+#  define SHUT_WR               SD_SEND
+# else
+#  define SHUT_WR               1
+# endif
+#endif
+#ifndef SHUT_RD
+# ifdef SD_RECEIVE
+#  define SHUT_RD               SD_RECEIVE
+# else
+#  define SHUT_RD               0
+# endif
+#endif
+
+/* fixup backlevel OSes. */
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+# define socklen_t              int
+#endif
+
+/** How many pending connection. */
+#define RTTCP_SERVER_BACKLOG    10
+
+/* Limit read and write sizes on Windows and OS/2. */
+#ifdef RT_OS_WINDOWS
+# define RTSOCKET_MAX_WRITE     (INT_MAX / 2)
+# define RTSOCKET_MAX_READ      (INT_MAX / 2)
+#elif defined(RT_OS_OS2)
+# define RTSOCKET_MAX_WRITE     0x10000
+# define RTSOCKET_MAX_READ      0x10000
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Socket handle data.
+ *
+ * This is mainly required for implementing RTPollSet on Windows.
+ */
+typedef struct RTSOCKETINT
+{
+    /** Magic number (RTSOCKET_MAGIC). */
+    uint32_t            u32Magic;
+    /** Exclusive user count.
+     * This is used to prevent two threads from accessing the handle concurrently.
+     * It can be higher than 1 if this handle is reference multiple times in a
+     * polling set (Windows). */
+    uint32_t volatile   cUsers;
+    /** The native socket handle. */
+    RTSOCKETNATIVE      hNative;
+    /** Indicates whether the handle has been closed or not. */
+    bool volatile       fClosed;
+    /** Indicates whether the socket is operating in blocking or non-blocking mode
+     * currently. */
+    bool                fBlocking;
+    /** Whether to leave the native socket open rather than closing it (for
+     * RTHandleGetStandard). */
+    bool                fLeaveOpen;
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+    /** The pollset currently polling this socket.  This is NIL if no one is
+     * polling. */
+    RTPOLLSET           hPollSet;
+#endif
+#ifdef RT_OS_WINDOWS
+    /** The event semaphore we've associated with the socket handle.
+     * This is WSA_INVALID_EVENT if not done. */
+    WSAEVENT            hEvent;
+    /** The events we're polling for. */
+    uint32_t            fPollEvts;
+    /** The events we're currently subscribing to with WSAEventSelect.
+     * This is ZERO if we're currently not subscribing to anything. */
+    uint32_t            fSubscribedEvts;
+    /** Saved events which are only posted once and events harvested for
+     * sockets entered multiple times into to a poll set.   Imagine a scenario where
+     * you have a RTPOLL_EVT_READ entry and RTPOLL_EVT_ERROR entry.  The READ
+     * condition can be triggered between checking the READ entry and the ERROR
+     * entry, and we don't want to drop the READ, so we store it here and make sure
+     * the event is signalled.
+     *
+     * The RTPOLL_EVT_ERROR is inconsistenly sticky at the momemnt... */
+    uint32_t            fEventsSaved;
+    /** Set if fEventsSaved contains harvested events (used to avoid multiple
+     *  calls to rtSocketPollCheck on the same socket during rtSocketPollDone). */
+    bool                fHarvestedEvents;
+    /** Set if we're using the polling fallback. */
+    bool                fPollFallback;
+    /** Set if the fallback polling is active (event not set). */
+    bool volatile       fPollFallbackActive;
+    /** Set to shut down the fallback polling thread. */
+    bool volatile       fPollFallbackShutdown;
+    /** Socket use to wake up the select thread. */
+    RTSOCKETNATIVE      hPollFallbackNotifyW;
+    /** Socket the select thread always waits on. */
+    RTSOCKETNATIVE      hPollFallbackNotifyR;
+    /** The fallback polling thread. */
+    RTTHREAD            hPollFallbackThread;
+#endif /* RT_OS_WINDOWS */
+} RTSOCKETINT;
+
+
+/**
+ * Address union used internally for things like getpeername and getsockname.
+ */
+typedef union RTSOCKADDRUNION
+{
+    struct sockaddr     Addr;
+    struct sockaddr_in  IPv4;
+#ifdef IPRT_WITH_TCPIP_V6
+    struct sockaddr_in6 IPv6;
+#endif
+} RTSOCKADDRUNION;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#ifdef RT_OS_WINDOWS
+/** Indicates that we've successfully initialized winsock.  */
+static uint32_t volatile g_uWinSockInitedVersion = 0;
+#endif
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+#ifdef RT_OS_WINDOWS
+static void rtSocketPokePollFallbackThread(RTSOCKETINT *pThis);
+#endif
+
+
+
+#ifdef RT_OS_WINDOWS
+/**
+ * Initializes winsock for the process.
+ *
+ * @returns IPRT status code.
+ */
+static int rtSocketInitWinsock(void)
+{
+    if (g_uWinSockInitedVersion != 0)
+        return VINF_SUCCESS;
+
+    if (   !g_pfnWSAGetLastError
+        || !g_pfnWSAStartup
+        || !g_pfnsocket
+        || !g_pfnclosesocket)
+        return VERR_NET_INIT_FAILED;
+
+    /*
+     * Initialize winsock. Try with 2.2 and back down till we get something that works.
+     */
+    static const WORD s_awVersions[] =
+    {
+        MAKEWORD(2, 2),
+        MAKEWORD(2, 1),
+        MAKEWORD(2, 0),
+        MAKEWORD(1, 1),
+        MAKEWORD(1, 0),
+    };
+    for (uint32_t i = 0; i < RT_ELEMENTS(s_awVersions); i++)
+    {
+        WSADATA     wsaData;
+        RT_ZERO(wsaData);
+        int rcWsa = g_pfnWSAStartup(s_awVersions[i], &wsaData);
+        if (rcWsa == 0)
+        {
+            /* AssertMsg(wsaData.wVersion >= s_awVersions[i]); - triggers with winsock 1.1 */
+            ASMAtomicWriteU32(&g_uWinSockInitedVersion, wsaData.wVersion);
+            return VINF_SUCCESS;
+        }
+        AssertLogRelMsg(rcWsa == WSAVERNOTSUPPORTED, ("rcWsa=%d (winsock version %#x)\n", rcWsa, s_awVersions[i]));
+    }
+    LogRel(("Failed to init winsock!\n"));
+    return VERR_NET_INIT_FAILED;
+}
+#endif
+
+
+/**
+ * Get the last error as an iprt status code.
+ *
+ * @returns IPRT status code.
+ */
+DECLINLINE(int) rtSocketError(void)
+{
+#ifdef RT_OS_WINDOWS
+    if (g_pfnWSAGetLastError)
+        return RTErrConvertFromWin32(g_pfnWSAGetLastError());
+    return VERR_NET_IO_ERROR;
+#else
+    return RTErrConvertFromErrno(errno);
+#endif
+}
+
+
+/**
+ * Resets the last error.
+ */
+DECLINLINE(void) rtSocketErrorReset(void)
+{
+#ifdef RT_OS_WINDOWS
+    if (g_pfnWSASetLastError)
+        g_pfnWSASetLastError(0);
+#else
+    errno = 0;
+#endif
+}
+
+
+/**
+ * Get the last resolver error as an iprt status code.
+ *
+ * @returns iprt status code.
+ */
+DECLHIDDEN(int) rtSocketResolverError(void)
+{
+#ifdef RT_OS_WINDOWS
+    if (g_pfnWSAGetLastError)
+        return RTErrConvertFromWin32(g_pfnWSAGetLastError());
+    return VERR_UNRESOLVED_ERROR;
+#else
+    switch (h_errno)
+    {
+        case HOST_NOT_FOUND:
+            return VERR_NET_HOST_NOT_FOUND;
+        case NO_DATA:
+            return VERR_NET_ADDRESS_NOT_AVAILABLE;
+        case NO_RECOVERY:
+            return VERR_IO_GEN_FAILURE;
+        case TRY_AGAIN:
+            return VERR_TRY_AGAIN;
+
+        default:
+            AssertLogRelMsgFailed(("Unhandled error %u\n", h_errno));
+            return VERR_UNRESOLVED_ERROR;
+    }
+#endif
+}
+
+
+/**
+ * Converts from a native socket address to a generic IPRT network address.
+ *
+ * @returns IPRT status code.
+ * @param   pSrc                The source address.
+ * @param   cbSrc               The size of the source address.
+ * @param   pAddr               Where to return the generic IPRT network
+ *                              address.
+ */
+static int rtSocketNetAddrFromAddr(RTSOCKADDRUNION const *pSrc, size_t cbSrc, PRTNETADDR pAddr)
+{
+    /*
+     * Convert the address.
+     */
+    if (   cbSrc == sizeof(struct sockaddr_in)
+        && pSrc->Addr.sa_family == AF_INET)
+    {
+        RT_ZERO(*pAddr);
+        pAddr->enmType      = RTNETADDRTYPE_IPV4;
+        pAddr->uPort        = RT_N2H_U16(pSrc->IPv4.sin_port);
+        pAddr->uAddr.IPv4.u = pSrc->IPv4.sin_addr.s_addr;
+    }
+#ifdef IPRT_WITH_TCPIP_V6
+    else if (   cbSrc == sizeof(struct sockaddr_in6)
+             && pSrc->Addr.sa_family == AF_INET6)
+    {
+        RT_ZERO(*pAddr);
+        pAddr->enmType            = RTNETADDRTYPE_IPV6;
+        pAddr->uPort              = RT_N2H_U16(pSrc->IPv6.sin6_port);
+        pAddr->uAddr.IPv6.au32[0] = pSrc->IPv6.sin6_addr.s6_addr32[0];
+        pAddr->uAddr.IPv6.au32[1] = pSrc->IPv6.sin6_addr.s6_addr32[1];
+        pAddr->uAddr.IPv6.au32[2] = pSrc->IPv6.sin6_addr.s6_addr32[2];
+        pAddr->uAddr.IPv6.au32[3] = pSrc->IPv6.sin6_addr.s6_addr32[3];
+    }
+#endif
+    else
+        return VERR_NET_ADDRESS_FAMILY_NOT_SUPPORTED;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Converts from a generic IPRT network address to a native socket address.
+ *
+ * @returns IPRT status code.
+ * @param   pAddr               Pointer to the generic IPRT network address.
+ * @param   pDst                The source address.
+ * @param   cbDst               The size of the source address.
+ * @param   pcbAddr             Where to store the size of the returned address.
+ *                              Optional
+ */
+static int rtSocketAddrFromNetAddr(PCRTNETADDR pAddr, RTSOCKADDRUNION *pDst, size_t cbDst, int *pcbAddr)
+{
+    RT_BZERO(pDst, cbDst);
+    if (pAddr->enmType == RTNETADDRTYPE_IPV4)
+    {
+        if (cbDst < sizeof(struct sockaddr_in))
+            return VERR_BUFFER_OVERFLOW;
+
+        pDst->Addr.sa_family       = AF_INET;
+        pDst->IPv4.sin_port        = RT_H2N_U16(pAddr->uPort);
+        pDst->IPv4.sin_addr.s_addr = pAddr->uAddr.IPv4.u;
+        if (pcbAddr)
+            *pcbAddr = sizeof(pDst->IPv4);
+    }
+#ifdef IPRT_WITH_TCPIP_V6
+    else if (pAddr->enmType == RTNETADDRTYPE_IPV6)
+    {
+        if (cbDst < sizeof(struct sockaddr_in6))
+            return VERR_BUFFER_OVERFLOW;
+
+        pDst->Addr.sa_family              = AF_INET6;
+        pDst->IPv6.sin6_port              = RT_H2N_U16(pAddr->uPort);
+        pSrc->IPv6.sin6_addr.s6_addr32[0] = pAddr->uAddr.IPv6.au32[0];
+        pSrc->IPv6.sin6_addr.s6_addr32[1] = pAddr->uAddr.IPv6.au32[1];
+        pSrc->IPv6.sin6_addr.s6_addr32[2] = pAddr->uAddr.IPv6.au32[2];
+        pSrc->IPv6.sin6_addr.s6_addr32[3] = pAddr->uAddr.IPv6.au32[3];
+        if (pcbAddr)
+            *pcbAddr = sizeof(pDst->IPv6);
+    }
+#endif
+    else
+        return VERR_NET_ADDRESS_FAMILY_NOT_SUPPORTED;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Tries to lock the socket for exclusive usage by the calling thread.
+ *
+ * Call rtSocketUnlock() to unlock.
+ *
+ * @returns @c true if locked, @c false if not.
+ * @param   pThis               The socket structure.
+ */
+DECLINLINE(bool) rtSocketTryLock(RTSOCKETINT *pThis)
+{
+    return ASMAtomicCmpXchgU32(&pThis->cUsers, 1, 0);
+}
+
+
+/**
+ * Unlocks the socket.
+ *
+ * @param   pThis               The socket structure.
+ */
+DECLINLINE(void) rtSocketUnlock(RTSOCKETINT *pThis)
+{
+    ASMAtomicCmpXchgU32(&pThis->cUsers, 0, 1);
+}
+
+
+/**
+ * The slow path of rtSocketSwitchBlockingMode that does the actual switching.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The socket structure.
+ * @param   fBlocking           The desired mode of operation.
+ * @remarks Do not call directly.
+ */
+static int rtSocketSwitchBlockingModeSlow(RTSOCKETINT *pThis, bool fBlocking)
+{
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnioctlsocket, VERR_NET_NOT_UNSUPPORTED);
+    u_long uBlocking = fBlocking ? 0 : 1;
+    if (g_pfnioctlsocket(pThis->hNative, FIONBIO, &uBlocking))
+        return rtSocketError();
+
+#else
+    int fFlags = fcntl(pThis->hNative, F_GETFL, 0);
+    if (fFlags == -1)
+        return rtSocketError();
+
+    if (fBlocking)
+        fFlags &= ~O_NONBLOCK;
+    else
+        fFlags |= O_NONBLOCK;
+    if (fcntl(pThis->hNative, F_SETFL, fFlags) == -1)
+       return rtSocketError();
+#endif
+
+    pThis->fBlocking = fBlocking;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Switches the socket to the desired blocking mode if necessary.
+ *
+ * The socket must be locked.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The socket structure.
+ * @param   fBlocking           The desired mode of operation.
+ */
+DECLINLINE(int) rtSocketSwitchBlockingMode(RTSOCKETINT *pThis, bool fBlocking)
+{
+    if (pThis->fBlocking != fBlocking)
+        return rtSocketSwitchBlockingModeSlow(pThis, fBlocking);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Creates an IPRT socket handle for a native one.
+ *
+ * @returns IPRT status code.
+ * @param   ppSocket        Where to return the IPRT socket handle.
+ * @param   hNative         The native handle.
+ * @param   fLeaveOpen      Whether to leave the native socket handle open when
+ *                          closed.
+ */
+DECLHIDDEN(int) rtSocketCreateForNative(RTSOCKETINT **ppSocket, RTSOCKETNATIVE hNative, bool fLeaveOpen)
+{
+    RTSOCKETINT *pThis = (RTSOCKETINT *)RTMemPoolAlloc(RTMEMPOOL_DEFAULT, sizeof(*pThis));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+    pThis->u32Magic         = RTSOCKET_MAGIC;
+    pThis->cUsers           = 0;
+    pThis->hNative          = hNative;
+    pThis->fClosed          = false;
+    pThis->fLeaveOpen       = fLeaveOpen;
+    pThis->fBlocking        = true;
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+    pThis->hPollSet         = NIL_RTPOLLSET;
+#endif
+#ifdef RT_OS_WINDOWS
+    pThis->hEvent                   = WSA_INVALID_EVENT;
+    pThis->fPollEvts                = 0;
+    pThis->fSubscribedEvts          = 0;
+    pThis->fEventsSaved             = 0;
+    pThis->fHarvestedEvents         = false;
+    pThis->fPollFallback            = g_uWinSockInitedVersion < MAKEWORD(2, 0)
+                                   || g_pfnWSACreateEvent == NULL
+                                   || g_pfnWSACloseEvent == NULL
+                                   || g_pfnWSAEventSelect == NULL
+                                   || g_pfnWSAEnumNetworkEvents == NULL;
+    pThis->fPollFallbackActive      = false;
+    pThis->fPollFallbackShutdown    = false;
+    pThis->hPollFallbackNotifyR     = NIL_RTSOCKETNATIVE;
+    pThis->hPollFallbackNotifyW     = NIL_RTSOCKETNATIVE;
+    pThis->hPollFallbackThread      = NIL_RTTHREAD;
+#endif
+    *ppSocket = pThis;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSocketFromNative(PRTSOCKET phSocket, RTHCINTPTR uNative)
+{
+    AssertReturn(uNative != NIL_RTSOCKETNATIVE, VERR_INVALID_PARAMETER);
+#ifndef RT_OS_WINDOWS
+    AssertReturn(uNative >= 0, VERR_INVALID_PARAMETER);
+#endif
+    AssertPtrReturn(phSocket, VERR_INVALID_POINTER);
+    return rtSocketCreateForNative(phSocket, uNative, false /*fLeaveOpen*/);
+}
+
+
+/**
+ * Wrapper around socket().
+ *
+ * @returns IPRT status code.
+ * @param   phSocket            Where to store the handle to the socket on
+ *                              success.
+ * @param   iDomain             The protocol family (PF_XXX).
+ * @param   iType               The socket type (SOCK_XXX).
+ * @param   iProtocol           Socket parameter, usually 0.
+ * @param   fInheritable        Set to true if the socket should be inherted by
+ *                              child processes, false if not inheritable.
+ */
+DECLHIDDEN(int) rtSocketCreate(PRTSOCKET phSocket, int iDomain, int iType, int iProtocol, bool fInheritable)
+{
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsocket, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnclosesocket, VERR_NET_NOT_UNSUPPORTED);
+
+    /* Initialize WinSock. */
+    int rc2 = rtSocketInitWinsock();
+    if (RT_FAILURE(rc2))
+        return rc2;
+#endif
+
+    /*
+     * Create the socket.
+     *
+     * The RTSocketSetInheritance operation isn't necessarily reliable on windows,
+     * so try use WSA_FLAG_NO_HANDLE_INHERIT with WSASocketW when possible.
+     */
+#ifdef RT_OS_WINDOWS
+    bool           fCallSetInheritance = true;
+    RTSOCKETNATIVE hNative;
+    if (g_pfnWSASocketW)
+    {
+        DWORD fWsaFlags = WSA_FLAG_OVERLAPPED | (!fInheritable ? WSA_FLAG_NO_HANDLE_INHERIT : 0);
+        hNative = g_pfnWSASocketW(iDomain, iType, iProtocol, NULL, 0 /*Group*/, fWsaFlags);
+        if (hNative != NIL_RTSOCKETNATIVE)
+            fCallSetInheritance = false;
+        else
+        {
+            if (!fInheritable)
+                hNative = g_pfnsocket(iDomain, iType, iProtocol);
+            if (hNative == NIL_RTSOCKETNATIVE)
+                return rtSocketError();
+        }
+    }
+    else
+    {
+        hNative = g_pfnsocket(iDomain, iType, iProtocol);
+        if (hNative == NIL_RTSOCKETNATIVE)
+            return rtSocketError();
+    }
+#else
+    RTSOCKETNATIVE hNative = socket(iDomain, iType, iProtocol);
+    if (hNative == NIL_RTSOCKETNATIVE)
+        return rtSocketError();
+#endif
+
+    /*
+     * Wrap it.
+     */
+    int rc = rtSocketCreateForNative(phSocket, hNative, false /*fLeaveOpen*/);
+    if (RT_SUCCESS(rc))
+    {
+#ifdef RT_OS_WINDOWS
+        if (fCallSetInheritance)
+#endif
+            RTSocketSetInheritance(*phSocket, fInheritable);
+    }
+    else
+    {
+#ifdef RT_OS_WINDOWS
+        g_pfnclosesocket(hNative);
+#else
+        close(hNative);
+#endif
+    }
+    return rc;
+}
+
+
+/**
+ * Wrapper around socketpair() for creating a local TCP connection.
+ *
+ * @returns IPRT status code.
+ * @param   phServer            Where to return the first native socket.
+ * @param   phClient            Where to return the second native socket.
+ */
+static int rtSocketCreateNativeTcpPair(RTSOCKETNATIVE *phServer, RTSOCKETNATIVE *phClient)
+{
+#ifdef RT_OS_WINDOWS
+    /*
+     * Initialize WinSock and make sure we got the necessary APIs.
+     */
+    int rc = rtSocketInitWinsock();
+    if (RT_FAILURE(rc))
+        return rc;
+    AssertReturn(g_pfnsocket, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnclosesocket, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnsetsockopt, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnbind, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfngetsockname, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnlisten, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnaccept, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnconnect, VERR_NET_NOT_UNSUPPORTED);
+
+    /*
+     * Create the "server" listen socket and the "client" socket.
+     */
+    RTSOCKETNATIVE hListener = g_pfnsocket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    if (hListener == NIL_RTSOCKETNATIVE)
+        return rtSocketError();
+    RTSOCKETNATIVE hClient = g_pfnsocket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    if (hClient != NIL_RTSOCKETNATIVE)
+    {
+
+        /*
+         * We let WinSock choose a port number when we bind.
+         */
+        union
+        {
+            struct sockaddr_in  Ip;
+            struct sockaddr     Generic;
+        } uAddr;
+        RT_ZERO(uAddr);
+        uAddr.Ip.sin_family      = AF_INET;
+        uAddr.Ip.sin_addr.s_addr = RT_H2N_U32_C(INADDR_LOOPBACK);
+        //uAddr.Ip.sin_port      = 0;
+        int fReuse = 1;
+        rc = g_pfnsetsockopt(hListener, SOL_SOCKET, SO_REUSEADDR, (const char *)&fReuse, sizeof(fReuse));
+        if (rc == 0)
+        {
+            rc = g_pfnbind(hListener, &uAddr.Generic, sizeof(uAddr.Ip));
+            if (rc == 0)
+            {
+                /*
+                 * Get the address the client should connect to.  According to the docs,
+                 * we cannot assume that getsockname sets the IP and family.
+                 */
+                RT_ZERO(uAddr);
+                int cbAddr = sizeof(uAddr.Ip);
+                rc = g_pfngetsockname(hListener, &uAddr.Generic, &cbAddr);
+                if (rc == 0)
+                {
+                    uAddr.Ip.sin_family      = AF_INET;
+                    uAddr.Ip.sin_addr.s_addr = RT_H2N_U32_C(INADDR_LOOPBACK);
+
+                    /*
+                     * Listen, connect and accept.
+                     */
+                    rc = g_pfnlisten(hListener, 1 /*cBacklog*/);
+                    if (rc == 0)
+                    {
+                        rc = g_pfnconnect(hClient, &uAddr.Generic, sizeof(uAddr.Ip));
+                        if (rc == 0)
+                        {
+                            RTSOCKETNATIVE hServer = g_pfnaccept(hListener, NULL, NULL);
+                            if (hServer != NIL_RTSOCKETNATIVE)
+                            {
+                                g_pfnclosesocket(hListener);
+
+                                /*
+                                 * Done!
+                                 */
+                                *phServer = hServer;
+                                *phClient = hClient;
+                                return VINF_SUCCESS;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        rc = rtSocketError();
+        g_pfnclosesocket(hClient);
+    }
+    else
+        rc = rtSocketError();
+    g_pfnclosesocket(hListener);
+    return rc;
+
+#else
+    /*
+     * Got socket pair, so use it.
+     * Note! This isn't TCP per se, but it should fool the users.
+     */
+    int aSockets[2] = { -1, -1 };
+    if (socketpair(AF_LOCAL, SOCK_STREAM, 0, aSockets) == 0)
+    {
+        *phServer = aSockets[0];
+        *phClient = aSockets[1];
+        return VINF_SUCCESS;
+    }
+    return rtSocketError();
+#endif
+}
+
+
+/**
+ * Worker for RTTcpCreatePair.
+ *
+ * @returns IPRT status code.
+ * @param   phServer            Where to return the "server" side of the pair.
+ * @param   phClient            Where to return the "client" side of the pair.
+ * @note    There is no server or client side, but we gotta call it something.
+ */
+DECLHIDDEN(int) rtSocketCreateTcpPair(RTSOCKET *phServer, RTSOCKET *phClient)
+{
+    RTSOCKETNATIVE hServer = NIL_RTSOCKETNATIVE;
+    RTSOCKETNATIVE hClient = NIL_RTSOCKETNATIVE;
+    int rc = rtSocketCreateNativeTcpPair(&hServer, &hClient);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtSocketCreateForNative(phServer, hServer, false /*fLeaveOpen*/);
+        if (RT_SUCCESS(rc))
+        {
+            rc = rtSocketCreateForNative(phClient, hClient, false /*fLeaveOpen*/);
+            if (RT_SUCCESS(rc))
+                return VINF_SUCCESS;
+            RTSocketRelease(*phServer);
+        }
+        else
+        {
+#ifdef RT_OS_WINDOWS
+            g_pfnclosesocket(hServer);
+#else
+            close(hServer);
+#endif
+        }
+#ifdef RT_OS_WINDOWS
+        g_pfnclosesocket(hClient);
+#else
+        close(hClient);
+#endif
+    }
+
+    *phServer = NIL_RTSOCKET;
+    *phClient = NIL_RTSOCKET;
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTSocketRetain(RTSOCKET hSocket)
+{
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, UINT32_MAX);
+    return RTMemPoolRetain(pThis);
+}
+
+
+/**
+ * Worker for RTSocketRelease and RTSocketClose.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The socket handle instance data.
+ * @param   fDestroy            Whether we're reaching ref count zero.
+ */
+static int rtSocketCloseIt(RTSOCKETINT *pThis, bool fDestroy)
+{
+    /*
+     * Invalidate the handle structure on destroy.
+     */
+    if (fDestroy)
+    {
+        Assert(ASMAtomicReadU32(&pThis->u32Magic) == RTSOCKET_MAGIC);
+        ASMAtomicWriteU32(&pThis->u32Magic, RTSOCKET_MAGIC_DEAD);
+    }
+
+    int rc = VINF_SUCCESS;
+    if (ASMAtomicCmpXchgBool(&pThis->fClosed, true, false))
+    {
+#ifdef RT_OS_WINDOWS
+        /*
+         * Poke the polling thread if active and give it a small chance to stop.
+         */
+        if (   pThis->fPollFallback
+            && pThis->hPollFallbackThread != NIL_RTTHREAD)
+        {
+            ASMAtomicWriteBool(&pThis->fPollFallbackShutdown, true);
+            rtSocketPokePollFallbackThread(pThis);
+            int rc2 = RTThreadWait(pThis->hPollFallbackThread, RT_MS_1SEC, NULL);
+            if (RT_SUCCESS(rc2))
+                pThis->hPollFallbackThread = NIL_RTTHREAD;
+        }
+#endif
+
+        /*
+         * Close the native handle.
+         */
+        RTSOCKETNATIVE hNative = pThis->hNative;
+        if (hNative != NIL_RTSOCKETNATIVE)
+        {
+            pThis->hNative = NIL_RTSOCKETNATIVE;
+
+            if (!pThis->fLeaveOpen)
+            {
+#ifdef RT_OS_WINDOWS
+                AssertReturn(g_pfnclosesocket, VERR_NET_NOT_UNSUPPORTED);
+                if (g_pfnclosesocket(hNative))
+#else
+                if (close(hNative))
+#endif
+                {
+                    rc = rtSocketError();
+#ifdef RT_OS_WINDOWS
+                    AssertMsgFailed(("closesocket(%p) -> %Rrc\n", (uintptr_t)hNative, rc));
+#else
+                    AssertMsgFailed(("close(%d) -> %Rrc\n", hNative, rc));
+#endif
+                }
+            }
+        }
+
+#ifdef RT_OS_WINDOWS
+        /*
+         * Windows specific polling cleanup.
+         */
+        WSAEVENT hEvent = pThis->hEvent;
+        if (hEvent != WSA_INVALID_EVENT)
+        {
+            pThis->hEvent = WSA_INVALID_EVENT;
+            if (!pThis->fPollFallback)
+            {
+                Assert(g_pfnWSACloseEvent);
+                if (g_pfnWSACloseEvent)
+                    g_pfnWSACloseEvent(hEvent);
+            }
+            else
+                CloseHandle(hEvent);
+        }
+
+        if (pThis->fPollFallback)
+        {
+            if (pThis->hPollFallbackNotifyW != NIL_RTSOCKETNATIVE)
+            {
+                g_pfnclosesocket(pThis->hPollFallbackNotifyW);
+                pThis->hPollFallbackNotifyW = NIL_RTSOCKETNATIVE;
+            }
+
+            if (pThis->hPollFallbackThread != NIL_RTTHREAD)
+            {
+                int rc2 = RTThreadWait(pThis->hPollFallbackThread, RT_MS_1MIN / 2, NULL);
+                AssertRC(rc2);
+                pThis->hPollFallbackThread = NIL_RTTHREAD;
+            }
+
+            if (pThis->hPollFallbackNotifyR != NIL_RTSOCKETNATIVE)
+            {
+                g_pfnclosesocket(pThis->hPollFallbackNotifyR);
+                pThis->hPollFallbackNotifyR = NIL_RTSOCKETNATIVE;
+            }
+        }
+#endif
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTSocketRelease(RTSOCKET hSocket)
+{
+    RTSOCKETINT *pThis = hSocket;
+    if (pThis == NIL_RTSOCKET)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, UINT32_MAX);
+
+    /* get the refcount without killing it... */
+    uint32_t cRefs = RTMemPoolRefCount(pThis);
+    AssertReturn(cRefs != UINT32_MAX, UINT32_MAX);
+    if (cRefs == 1)
+        rtSocketCloseIt(pThis, true);
+
+    return RTMemPoolRelease(RTMEMPOOL_DEFAULT, pThis);
+}
+
+
+RTDECL(int) RTSocketClose(RTSOCKET hSocket)
+{
+    RTSOCKETINT *pThis = hSocket;
+    if (pThis == NIL_RTSOCKET)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+
+    uint32_t cRefs = RTMemPoolRefCount(pThis);
+    AssertReturn(cRefs != UINT32_MAX, UINT32_MAX);
+
+    int rc = rtSocketCloseIt(pThis, cRefs == 1);
+
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pThis);
+    return rc;
+}
+
+
+RTDECL(RTHCUINTPTR) RTSocketToNative(RTSOCKET hSocket)
+{
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, RTHCUINTPTR_MAX);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, RTHCUINTPTR_MAX);
+    return (RTHCUINTPTR)pThis->hNative;
+}
+
+
+RTDECL(int) RTSocketSetInheritance(RTSOCKET hSocket, bool fInheritable)
+{
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+
+#ifndef RT_OS_WINDOWS
+    if (fcntl(pThis->hNative, F_SETFD, fInheritable ? 0 : FD_CLOEXEC) < 0)
+        return RTErrConvertFromErrno(errno);
+    return VINF_SUCCESS;
+#else
+    /* Windows is more complicated as sockets are complicated wrt inheritance
+       (see stackoverflow for details).  In general, though we cannot hope to
+       make a socket really non-inheritable before vista as other layers in
+       the winsock maze may have additional handles associated with the socket. */
+    if (g_pfnGetHandleInformation)
+    {
+        /* Check if the handle is already in what seems to be the right state
+           before we try doing anything. */
+        DWORD fFlags;
+        if (g_pfnGetHandleInformation((HANDLE)pThis->hNative, &fFlags))
+        {
+            if (RT_BOOL(fFlags & HANDLE_FLAG_INHERIT) == fInheritable)
+                return VINF_SUCCESS;
+        }
+    }
+
+    if (!g_pfnSetHandleInformation)
+        return VERR_NET_NOT_UNSUPPORTED;
+
+    if (!g_pfnSetHandleInformation((HANDLE)pThis->hNative, HANDLE_FLAG_INHERIT, fInheritable ? HANDLE_FLAG_INHERIT : 0))
+        return RTErrConvertFromWin32(GetLastError());
+    /** @todo Need we do something related to WS_SIO_ASSOCIATE_HANDLE or
+     *        WS_SIO_TRANSLATE_HANDLE? Or what  other handles could be associated
+     *        with the socket? that we need to modify? */
+
+    return VINF_SUCCESS;
+#endif
+}
+
+
+static bool rtSocketIsIPv4Numerical(const char *pszAddress, PRTNETADDRIPV4 pAddr)
+{
+
+    /* Empty address resolves to the INADDR_ANY address (good for bind). */
+    if (!pszAddress || !*pszAddress)
+    {
+        pAddr->u = INADDR_ANY;
+        return true;
+    }
+
+    /* Four quads? */
+    char *psz = (char *)pszAddress;
+    for (int i = 0; i < 4; i++)
+    {
+        uint8_t u8;
+        int rc = RTStrToUInt8Ex(psz, &psz, 0, &u8);
+        if (rc != VINF_SUCCESS && rc != VWRN_TRAILING_CHARS)
+            return false;
+        if (*psz != (i < 3 ? '.' : '\0'))
+            return false;
+        psz++;
+
+        pAddr->au8[i] = u8;             /* big endian */
+    }
+
+    return true;
+}
+
+RTDECL(int) RTSocketParseInetAddress(const char *pszAddress, unsigned uPort, PRTNETADDR pAddr)
+{
+    int rc;
+
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pszAddress, VERR_INVALID_POINTER);
+
+    /*
+     * Resolve the address. Pretty crude at the moment, but we have to make
+     * sure to not ask the NT 4 gethostbyname about an IPv4 address as it may
+     * give a wrong answer.
+     */
+    /** @todo this only supports IPv4, and IPv6 support needs to be added.
+     * It probably needs to be converted to getaddrinfo(). */
+    RTNETADDRIPV4 IPv4Quad;
+    if (rtSocketIsIPv4Numerical(pszAddress, &IPv4Quad))
+    {
+        Log3(("rtSocketIsIPv4Numerical: %s -> %#x (%RTnaipv4)\n", pszAddress, IPv4Quad.u, IPv4Quad));
+        RT_ZERO(*pAddr);
+        pAddr->enmType      = RTNETADDRTYPE_IPV4;
+        pAddr->uPort        = uPort;
+        pAddr->uAddr.IPv4   = IPv4Quad;
+        return VINF_SUCCESS;
+    }
+
+#ifdef RT_OS_WINDOWS
+    /* Initialize WinSock and check version before we call gethostbyname. */
+    if (!g_pfngethostbyname)
+        return VERR_NET_NOT_UNSUPPORTED;
+
+    int rc2 = rtSocketInitWinsock();
+    if (RT_FAILURE(rc2))
+        return rc2;
+
+# define gethostbyname g_pfngethostbyname
+#endif
+
+    struct hostent *pHostEnt;
+    pHostEnt = gethostbyname(pszAddress);
+    if (!pHostEnt)
+    {
+        rc = rtSocketResolverError();
+        AssertMsg(rc == VERR_NET_HOST_NOT_FOUND,
+                  ("Could not resolve '%s', rc=%Rrc\n", pszAddress, rc));
+        return rc;
+    }
+
+    if (pHostEnt->h_addrtype == AF_INET)
+    {
+        RT_ZERO(*pAddr);
+        pAddr->enmType      = RTNETADDRTYPE_IPV4;
+        pAddr->uPort        = uPort;
+        pAddr->uAddr.IPv4.u = ((struct in_addr *)pHostEnt->h_addr)->s_addr;
+        Log3(("gethostbyname: %s -> %#x (%RTnaipv4)\n", pszAddress, pAddr->uAddr.IPv4.u, pAddr->uAddr.IPv4));
+    }
+    else
+        return VERR_NET_ADDRESS_FAMILY_NOT_SUPPORTED;
+
+#ifdef RT_OS_WINDOWS
+# undef gethostbyname
+#endif
+    return VINF_SUCCESS;
+}
+
+
+/*
+ * New function to allow both ipv4 and ipv6 addresses to be resolved.
+ * Breaks compatibility with windows before 2000.
+ */
+RTDECL(int) RTSocketQueryAddressStr(const char *pszHost, char *pszResult, size_t *pcbResult, PRTNETADDRTYPE penmAddrType)
+{
+    AssertPtrReturn(pszHost, VERR_INVALID_POINTER);
+    AssertPtrReturn(pcbResult, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(penmAddrType, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pszResult, VERR_INVALID_POINTER);
+
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS) /** @todo dynamically resolve the APIs not present in NT4! */
+    return VERR_NOT_SUPPORTED;
+
+#else
+    int rc;
+    if (*pcbResult < 16)
+        return VERR_NET_ADDRESS_NOT_AVAILABLE;
+
+    /* Setup the hint. */
+    struct addrinfo grHints;
+    RT_ZERO(grHints);
+    grHints.ai_socktype = 0;
+    grHints.ai_flags    = 0;
+    grHints.ai_protocol = 0;
+    grHints.ai_family   = AF_UNSPEC;
+    if (penmAddrType)
+    {
+        switch (*penmAddrType)
+        {
+            case RTNETADDRTYPE_INVALID:
+                /*grHints.ai_family = AF_UNSPEC;*/
+                break;
+            case RTNETADDRTYPE_IPV4:
+                grHints.ai_family = AF_INET;
+                break;
+            case RTNETADDRTYPE_IPV6:
+                grHints.ai_family = AF_INET6;
+                break;
+            default:
+                AssertFailedReturn(VERR_INVALID_PARAMETER);
+        }
+    }
+
+# ifdef RT_OS_WINDOWS
+    /*
+     * Winsock2 init
+     */
+    if (   !g_pfngetaddrinfo
+        || !g_pfnfreeaddrinfo)
+        return VERR_NET_NOT_UNSUPPORTED;
+
+    int rc2 = rtSocketInitWinsock();
+    if (RT_FAILURE(rc2))
+        return rc2;
+
+#  define getaddrinfo  g_pfngetaddrinfo
+#  define freeaddrinfo g_pfnfreeaddrinfo
+# endif
+
+    /** @todo r=bird: getaddrinfo and freeaddrinfo breaks the additions on NT4. */
+    struct addrinfo *pgrResults = NULL;
+    rc = getaddrinfo(pszHost, "", &grHints, &pgrResults);
+    if (rc != 0)
+        return VERR_NET_ADDRESS_NOT_AVAILABLE;
+
+    // return data
+    // on multiple matches return only the first one
+
+    if (!pgrResults)
+        return VERR_NET_ADDRESS_NOT_AVAILABLE;
+
+    struct addrinfo const *pgrResult = pgrResults->ai_next;
+    if (!pgrResult)
+    {
+        freeaddrinfo(pgrResults);
+        return VERR_NET_ADDRESS_NOT_AVAILABLE;
+    }
+
+    RTNETADDRTYPE   enmAddrType = RTNETADDRTYPE_INVALID;
+    size_t          cchIpAddress;
+    char            szIpAddress[48];
+    if (pgrResult->ai_family == AF_INET)
+    {
+        struct sockaddr_in const *pgrSa = (struct sockaddr_in const *)pgrResult->ai_addr;
+        cchIpAddress = RTStrPrintf(szIpAddress, sizeof(szIpAddress),
+                                   "%RTnaipv4", pgrSa->sin_addr.s_addr);
+        Assert(cchIpAddress >= 7 && cchIpAddress < sizeof(szIpAddress) - 1);
+        enmAddrType = RTNETADDRTYPE_IPV4;
+        rc = VINF_SUCCESS;
+    }
+    else if (pgrResult->ai_family == AF_INET6)
+    {
+        struct sockaddr_in6 const *pgrSa6 = (struct sockaddr_in6 const *)pgrResult->ai_addr;
+        cchIpAddress = RTStrPrintf(szIpAddress, sizeof(szIpAddress),
+                                   "%RTnaipv6", (PRTNETADDRIPV6)&pgrSa6->sin6_addr);
+        enmAddrType = RTNETADDRTYPE_IPV6;
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        rc = VERR_NET_ADDRESS_NOT_AVAILABLE;
+        szIpAddress[0] = '\0';
+        cchIpAddress = 0;
+    }
+    freeaddrinfo(pgrResults);
+
+    /*
+     * Copy out the result.
+     */
+    size_t const cbResult = *pcbResult;
+    *pcbResult = cchIpAddress + 1;
+    if (cchIpAddress < cbResult)
+        memcpy(pszResult, szIpAddress, cchIpAddress + 1);
+    else
+    {
+        RT_BZERO(pszResult, cbResult);
+        if (RT_SUCCESS(rc))
+            rc = VERR_BUFFER_OVERFLOW;
+    }
+    if (penmAddrType && RT_SUCCESS(rc))
+        *penmAddrType = enmAddrType;
+    return rc;
+
+# ifdef RT_OS_WINDOWS
+#  undef getaddrinfo
+#  undef freeaddrinfo
+# endif
+#endif /* !RT_OS_OS2 */
+}
+
+
+RTDECL(int) RTSocketRead(RTSOCKET hSocket, void *pvBuffer, size_t cbBuffer, size_t *pcbRead)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(cbBuffer > 0, VERR_INVALID_PARAMETER);
+    AssertPtr(pvBuffer);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnrecv, VERR_NET_NOT_UNSUPPORTED);
+# define recv g_pfnrecv
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Read loop.
+     * If pcbRead is NULL we have to fill the entire buffer!
+     */
+    size_t  cbRead   = 0;
+    size_t  cbToRead = cbBuffer;
+    for (;;)
+    {
+        rtSocketErrorReset();
+#ifdef RTSOCKET_MAX_READ
+        int    cbNow = cbToRead >= RTSOCKET_MAX_READ ? RTSOCKET_MAX_READ : (int)cbToRead;
+#else
+        size_t cbNow = cbToRead;
+#endif
+        ssize_t cbBytesRead = recv(pThis->hNative, (char *)pvBuffer + cbRead, cbNow, MSG_NOSIGNAL);
+        if (cbBytesRead <= 0)
+        {
+            rc = rtSocketError();
+            Assert(RT_FAILURE_NP(rc) || cbBytesRead == 0);
+            if (RT_SUCCESS_NP(rc))
+            {
+                if (!pcbRead)
+                    rc = VERR_NET_SHUTDOWN;
+                else
+                {
+                    *pcbRead = 0;
+                    rc = VINF_SUCCESS;
+                }
+            }
+            break;
+        }
+        if (pcbRead)
+        {
+            /* return partial data */
+            *pcbRead = cbBytesRead;
+            break;
+        }
+
+        /* read more? */
+        cbRead += cbBytesRead;
+        if (cbRead == cbBuffer)
+            break;
+
+        /* next */
+        cbToRead = cbBuffer - cbRead;
+    }
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef recv
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketReadFrom(RTSOCKET hSocket, void *pvBuffer, size_t cbBuffer, size_t *pcbRead, PRTNETADDR pSrcAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(cbBuffer > 0, VERR_INVALID_PARAMETER);
+    AssertPtr(pvBuffer);
+    AssertPtr(pcbRead);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnrecvfrom, VERR_NET_NOT_UNSUPPORTED);
+# define recvfrom g_pfnrecvfrom
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Read data.
+     */
+    size_t  cbRead   = 0;
+    size_t  cbToRead = cbBuffer;
+    rtSocketErrorReset();
+    RTSOCKADDRUNION u;
+#ifdef RTSOCKET_MAX_READ
+    int       cbNow  = cbToRead >= RTSOCKET_MAX_READ ? RTSOCKET_MAX_READ : (int)cbToRead;
+    int       cbAddr = sizeof(u);
+#else
+    size_t    cbNow  = cbToRead;
+    socklen_t cbAddr = sizeof(u);
+#endif
+    ssize_t cbBytesRead = recvfrom(pThis->hNative, (char *)pvBuffer + cbRead, cbNow, MSG_NOSIGNAL, &u.Addr, &cbAddr);
+    if (cbBytesRead <= 0)
+    {
+        rc = rtSocketError();
+        Assert(RT_FAILURE_NP(rc) || cbBytesRead == 0);
+        if (RT_SUCCESS_NP(rc))
+        {
+            *pcbRead = 0;
+            rc = VINF_SUCCESS;
+        }
+    }
+    else
+    {
+        if (pSrcAddr)
+            rc = rtSocketNetAddrFromAddr(&u, cbAddr, pSrcAddr);
+        *pcbRead = cbBytesRead;
+    }
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef recvfrom
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketWrite(RTSOCKET hSocket, const void *pvBuffer, size_t cbBuffer)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsend, VERR_NET_NOT_UNSUPPORTED);
+# define send g_pfnsend
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Try write all at once.
+     */
+#ifdef RTSOCKET_MAX_WRITE
+    int     cbNow     = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+#else
+    size_t  cbNow     = cbBuffer >= SSIZE_MAX   ? SSIZE_MAX   :      cbBuffer;
+#endif
+    ssize_t cbWritten = send(pThis->hNative, (const char *)pvBuffer, cbNow, MSG_NOSIGNAL);
+    if (RT_LIKELY((size_t)cbWritten == cbBuffer && cbWritten >= 0))
+        rc = VINF_SUCCESS;
+    else if (cbWritten < 0)
+        rc = rtSocketError();
+    else
+    {
+        /*
+         * Unfinished business, write the remainder of the request.  Must ignore
+         * VERR_INTERRUPTED here if we've managed to send something.
+         */
+        size_t cbSentSoFar = 0;
+        for (;;)
+        {
+            /* advance */
+            cbBuffer    -= (size_t)cbWritten;
+            if (!cbBuffer)
+                break;
+            cbSentSoFar += (size_t)cbWritten;
+            pvBuffer     = (char const *)pvBuffer + cbWritten;
+
+            /* send */
+#ifdef RTSOCKET_MAX_WRITE
+            cbNow = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+#else
+            cbNow = cbBuffer >= SSIZE_MAX   ? SSIZE_MAX   :      cbBuffer;
+#endif
+            cbWritten = send(pThis->hNative, (const char *)pvBuffer, cbNow, MSG_NOSIGNAL);
+            if (cbWritten >= 0)
+                AssertMsg(cbBuffer >= (size_t)cbWritten, ("Wrote more than we requested!!! cbWritten=%zu cbBuffer=%zu rtSocketError()=%d\n",
+                                                          cbWritten, cbBuffer, rtSocketError()));
+            else
+            {
+                rc = rtSocketError();
+                if (rc != VERR_INTERNAL_ERROR || cbSentSoFar == 0)
+                    break;
+                cbWritten = 0;
+                rc = VINF_SUCCESS;
+            }
+        }
+    }
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef send
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketWriteTo(RTSOCKET hSocket, const void *pvBuffer, size_t cbBuffer, PCRTNETADDR pAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsendto, VERR_NET_NOT_UNSUPPORTED);
+# define sendto g_pfnsendto
+#endif
+
+    /* no locking since UDP reads may be done concurrently to writes, and
+     * this is the normal use case of this code. */
+
+    int rc = rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Figure out destination address. */
+    struct sockaddr *pSA = NULL;
+#ifdef RT_OS_WINDOWS
+    int cbSA = 0;
+#else
+    socklen_t cbSA = 0;
+#endif
+    RTSOCKADDRUNION u;
+    if (pAddr)
+    {
+        rc = rtSocketAddrFromNetAddr(pAddr, &u, sizeof(u), NULL);
+        if (RT_FAILURE(rc))
+            return rc;
+        pSA = &u.Addr;
+        cbSA = sizeof(u);
+    }
+
+    /*
+     * Must write all at once, otherwise it is a failure.
+     */
+#ifdef RT_OS_WINDOWS
+    int     cbNow     = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+#else
+    size_t  cbNow     = cbBuffer >= SSIZE_MAX   ? SSIZE_MAX   :      cbBuffer;
+#endif
+    ssize_t cbWritten = sendto(pThis->hNative, (const char *)pvBuffer, cbNow, MSG_NOSIGNAL, pSA, cbSA);
+    if (RT_LIKELY((size_t)cbWritten == cbBuffer && cbWritten >= 0))
+        rc = VINF_SUCCESS;
+    else if (cbWritten < 0)
+        rc = rtSocketError();
+    else
+        rc = VERR_TOO_MUCH_DATA;
+
+    /// @todo rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef sendto
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketWriteToNB(RTSOCKET hSocket, const void *pvBuffer, size_t cbBuffer, PCRTNETADDR pAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsendto, VERR_NET_NOT_UNSUPPORTED);
+# define sendto g_pfnsendto
+#endif
+
+    /* no locking since UDP reads may be done concurrently to writes, and
+     * this is the normal use case of this code. */
+
+    int rc = rtSocketSwitchBlockingMode(pThis, false /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Figure out destination address. */
+    struct sockaddr *pSA = NULL;
+#ifdef RT_OS_WINDOWS
+    int cbSA = 0;
+#else
+    socklen_t cbSA = 0;
+#endif
+    RTSOCKADDRUNION u;
+    if (pAddr)
+    {
+        rc = rtSocketAddrFromNetAddr(pAddr, &u, sizeof(u), NULL);
+        if (RT_FAILURE(rc))
+            return rc;
+        pSA = &u.Addr;
+        cbSA = sizeof(u);
+    }
+
+    /*
+     * Must write all at once, otherwise it is a failure.
+     */
+#ifdef RT_OS_WINDOWS
+    int     cbNow     = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+#else
+    size_t  cbNow     = cbBuffer >= SSIZE_MAX   ? SSIZE_MAX   :      cbBuffer;
+#endif
+    ssize_t cbWritten = sendto(pThis->hNative, (const char *)pvBuffer, cbNow, MSG_NOSIGNAL, pSA, cbSA);
+    if (RT_LIKELY((size_t)cbWritten == cbBuffer && cbWritten >= 0))
+        rc = VINF_SUCCESS;
+    else if (cbWritten < 0)
+        rc = rtSocketError();
+    else
+        rc = VERR_TOO_MUCH_DATA;
+
+    /// @todo rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef sendto
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWrite(RTSOCKET hSocket, PCRTSGBUF pSgBuf)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pSgBuf, VERR_INVALID_PARAMETER);
+    AssertReturn(pSgBuf->cSegs > 0, VERR_INVALID_PARAMETER);
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Construct message descriptor (translate pSgBuf) and send it.
+     */
+    rc = VERR_NO_TMP_MEMORY;
+#ifdef RT_OS_WINDOWS
+    if (g_pfnWSASend)
+    {
+        AssertCompileSize(WSABUF, sizeof(RTSGSEG));
+        AssertCompileMemberSize(WSABUF, buf, RT_SIZEOFMEMB(RTSGSEG, pvSeg));
+
+        LPWSABUF paMsg = (LPWSABUF)RTMemTmpAllocZ(pSgBuf->cSegs * sizeof(WSABUF));
+        if (paMsg)
+        {
+            for (unsigned i = 0; i < pSgBuf->cSegs; i++)
+            {
+                paMsg[i].buf = (char *)pSgBuf->paSegs[i].pvSeg;
+                paMsg[i].len = (u_long)pSgBuf->paSegs[i].cbSeg;
+            }
+
+            DWORD dwSent;
+            int hrc = g_pfnWSASend(pThis->hNative, paMsg, pSgBuf->cSegs, &dwSent, MSG_NOSIGNAL, NULL, NULL);
+            if (!hrc)
+                rc = VINF_SUCCESS;
+    /** @todo check for incomplete writes */
+            else
+                rc = rtSocketError();
+
+            RTMemTmpFree(paMsg);
+        }
+    }
+    else if (g_pfnsend)
+    {
+        rc = VINF_SUCCESS;
+        for (uint32_t iSeg = 0; iSeg < pSgBuf->cSegs; iSeg++)
+        {
+            uint8_t const *pbSeg = (uint8_t const *)pSgBuf->paSegs[iSeg].pvSeg;
+            size_t         cbSeg = pSgBuf->paSegs[iSeg].cbSeg;
+            int            cbNow;
+            ssize_t        cbWritten;
+            for (;;)
+            {
+                cbNow = cbSeg >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbSeg;
+                cbWritten = g_pfnsend(pThis->hNative, (const char *)pbSeg, cbNow, MSG_NOSIGNAL);
+                if ((size_t)cbWritten >= cbSeg || cbWritten < 0)
+                    break;
+                pbSeg += cbWritten;
+                cbSeg -= cbWritten;
+            }
+            if (cbWritten < 0)
+            {
+                rc = rtSocketError();
+                break;
+            }
+        }
+    }
+    else
+        rc = VERR_NET_NOT_UNSUPPORTED;
+
+#else  /* !RT_OS_WINDOWS */
+    AssertCompileSize(struct iovec, sizeof(RTSGSEG));
+    AssertCompileMemberSize(struct iovec, iov_base, RT_SIZEOFMEMB(RTSGSEG, pvSeg));
+    AssertCompileMemberSize(struct iovec, iov_len,  RT_SIZEOFMEMB(RTSGSEG, cbSeg));
+
+    struct iovec *paMsg = (struct iovec *)RTMemTmpAllocZ(pSgBuf->cSegs * sizeof(struct iovec));
+    if (paMsg)
+    {
+        for (unsigned i = 0; i < pSgBuf->cSegs; i++)
+        {
+            paMsg[i].iov_base = pSgBuf->paSegs[i].pvSeg;
+            paMsg[i].iov_len  = pSgBuf->paSegs[i].cbSeg;
+        }
+
+        struct msghdr msgHdr;
+        RT_ZERO(msgHdr);
+        msgHdr.msg_iov    = paMsg;
+        msgHdr.msg_iovlen = pSgBuf->cSegs;
+        ssize_t cbWritten = sendmsg(pThis->hNative, &msgHdr, MSG_NOSIGNAL);
+        if (RT_LIKELY(cbWritten >= 0))
+            rc = VINF_SUCCESS;
+/** @todo check for incomplete writes */
+        else
+            rc = rtSocketError();
+
+        RTMemTmpFree(paMsg);
+    }
+#endif /* !RT_OS_WINDOWS */
+
+    rtSocketUnlock(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWriteL(RTSOCKET hSocket, size_t cSegs, ...)
+{
+    va_list va;
+    va_start(va, cSegs);
+    int rc = RTSocketSgWriteLV(hSocket, cSegs, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWriteLV(RTSOCKET hSocket, size_t cSegs, va_list va)
+{
+    /*
+     * Set up a S/G segment array + buffer on the stack and pass it
+     * on to RTSocketSgWrite.
+     */
+    Assert(cSegs <= 16);
+    PRTSGSEG paSegs = (PRTSGSEG)alloca(cSegs * sizeof(RTSGSEG));
+    AssertReturn(paSegs, VERR_NO_TMP_MEMORY);
+    for (size_t i = 0; i < cSegs; i++)
+    {
+        paSegs[i].pvSeg = va_arg(va, void *);
+        paSegs[i].cbSeg = va_arg(va, size_t);
+    }
+
+    RTSGBUF SgBuf;
+    RTSgBufInit(&SgBuf, paSegs, cSegs);
+    return RTSocketSgWrite(hSocket, &SgBuf);
+}
+
+
+RTDECL(int) RTSocketReadNB(RTSOCKET hSocket, void *pvBuffer, size_t cbBuffer, size_t *pcbRead)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(cbBuffer > 0, VERR_INVALID_PARAMETER);
+    AssertPtr(pvBuffer);
+    AssertPtrReturn(pcbRead, VERR_INVALID_PARAMETER);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnrecv, VERR_NET_NOT_UNSUPPORTED);
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, false /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rtSocketErrorReset();
+#ifdef RTSOCKET_MAX_READ
+    int    cbNow = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+#else
+    size_t cbNow = cbBuffer;
+#endif
+
+#ifdef RT_OS_WINDOWS
+    int cbRead = g_pfnrecv(pThis->hNative, (char *)pvBuffer, cbNow, MSG_NOSIGNAL);
+    if (cbRead >= 0)
+    {
+        *pcbRead = cbRead;
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        rc = rtSocketError();
+        if (rc == VERR_TRY_AGAIN)
+        {
+            *pcbRead = 0;
+            rc = VINF_TRY_AGAIN;
+        }
+    }
+
+#else
+    ssize_t cbRead = recv(pThis->hNative, pvBuffer, cbNow, MSG_NOSIGNAL);
+    if (cbRead >= 0)
+        *pcbRead = cbRead;
+    else if (   errno == EAGAIN
+# ifdef EWOULDBLOCK
+#  if EWOULDBLOCK != EAGAIN
+             || errno == EWOULDBLOCK
+#  endif
+# endif
+             )
+    {
+        *pcbRead = 0;
+        rc = VINF_TRY_AGAIN;
+    }
+    else
+        rc = rtSocketError();
+#endif
+
+    rtSocketUnlock(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketWriteNB(RTSOCKET hSocket, const void *pvBuffer, size_t cbBuffer, size_t *pcbWritten)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_PARAMETER);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsend, VERR_NET_NOT_UNSUPPORTED);
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, false /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    rtSocketErrorReset();
+#ifdef RT_OS_WINDOWS
+# ifdef RTSOCKET_MAX_WRITE
+    int    cbNow = cbBuffer >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbBuffer;
+# else
+    size_t cbNow = cbBuffer;
+# endif
+    int cbWritten = g_pfnsend(pThis->hNative, (const char *)pvBuffer, cbNow, MSG_NOSIGNAL);
+    if (cbWritten >= 0)
+    {
+        *pcbWritten = cbWritten;
+        rc = VINF_SUCCESS;
+    }
+    else
+    {
+        rc = rtSocketError();
+        if (rc == VERR_TRY_AGAIN)
+        {
+            *pcbWritten = 0;
+            rc = VINF_TRY_AGAIN;
+        }
+    }
+#else
+    ssize_t cbWritten = send(pThis->hNative, pvBuffer, cbBuffer, MSG_NOSIGNAL);
+    if (cbWritten >= 0)
+        *pcbWritten = cbWritten;
+    else if (   errno == EAGAIN
+# ifdef EWOULDBLOCK
+#  if EWOULDBLOCK != EAGAIN
+             || errno == EWOULDBLOCK
+#  endif
+# endif
+            )
+    {
+        *pcbWritten = 0;
+        rc = VINF_TRY_AGAIN;
+    }
+    else
+        rc = rtSocketError();
+#endif
+
+    rtSocketUnlock(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWriteNB(RTSOCKET hSocket, PCRTSGBUF pSgBuf, size_t *pcbWritten)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pSgBuf, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_PARAMETER);
+    AssertReturn(pSgBuf->cSegs > 0, VERR_INVALID_PARAMETER);
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = rtSocketSwitchBlockingMode(pThis, false /* fBlocking */);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    unsigned cSegsToSend = 0;
+    rc = VERR_NO_TMP_MEMORY;
+#ifdef RT_OS_WINDOWS
+    if (g_pfnWSASend)
+    {
+        LPWSABUF paMsg = NULL;
+        RTSgBufMapToNative(paMsg, pSgBuf, WSABUF, buf, char *, len, u_long, cSegsToSend);
+        if (paMsg)
+        {
+            DWORD dwSent = 0;
+            int hrc = g_pfnWSASend(pThis->hNative, paMsg, cSegsToSend, &dwSent, MSG_NOSIGNAL, NULL, NULL);
+            if (!hrc)
+                rc = VINF_SUCCESS;
+            else
+                rc = rtSocketError();
+
+            *pcbWritten = dwSent;
+
+            RTMemTmpFree(paMsg);
+        }
+    }
+    else if (g_pfnsend)
+    {
+        size_t cbWrittenTotal = 0;
+        rc = VINF_SUCCESS;
+        for (uint32_t iSeg = 0; iSeg < pSgBuf->cSegs; iSeg++)
+        {
+            uint8_t const *pbSeg = (uint8_t const *)pSgBuf->paSegs[iSeg].pvSeg;
+            size_t         cbSeg = pSgBuf->paSegs[iSeg].cbSeg;
+            int            cbNow;
+            ssize_t        cbWritten;
+            for (;;)
+            {
+                cbNow = cbSeg >= RTSOCKET_MAX_WRITE ? RTSOCKET_MAX_WRITE : (int)cbSeg;
+                cbWritten = g_pfnsend(pThis->hNative, (const char *)pbSeg, cbNow, MSG_NOSIGNAL);
+                if ((size_t)cbWritten >= cbSeg || cbWritten < 0)
+                    break;
+                cbWrittenTotal += cbWrittenTotal;
+                pbSeg += cbWritten;
+                cbSeg -= cbWritten;
+            }
+            if (cbWritten < 0)
+            {
+                rc = rtSocketError();
+                break;
+            }
+            if (cbWritten != cbNow)
+                break;
+        }
+        *pcbWritten = cbWrittenTotal;
+    }
+    else
+        rc = VERR_NET_NOT_UNSUPPORTED;
+
+#else  /* !RT_OS_WINDOWS */
+    struct iovec *paMsg = NULL;
+
+    RTSgBufMapToNative(paMsg, pSgBuf, struct iovec, iov_base, void *, iov_len, size_t, cSegsToSend);
+    if (paMsg)
+    {
+        struct msghdr msgHdr;
+        RT_ZERO(msgHdr);
+        msgHdr.msg_iov    = paMsg;
+        msgHdr.msg_iovlen = cSegsToSend;
+        ssize_t cbWritten = sendmsg(pThis->hNative, &msgHdr, MSG_NOSIGNAL);
+        if (RT_LIKELY(cbWritten >= 0))
+        {
+            rc = VINF_SUCCESS;
+            *pcbWritten = cbWritten;
+        }
+        else
+            rc = rtSocketError();
+
+        RTMemTmpFree(paMsg);
+    }
+#endif /* !RT_OS_WINDOWS */
+
+    rtSocketUnlock(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWriteLNB(RTSOCKET hSocket, size_t cSegs, size_t *pcbWritten, ...)
+{
+    va_list va;
+    va_start(va, pcbWritten);
+    int rc = RTSocketSgWriteLVNB(hSocket, cSegs, pcbWritten, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSgWriteLVNB(RTSOCKET hSocket, size_t cSegs, size_t *pcbWritten, va_list va)
+{
+    /*
+     * Set up a S/G segment array + buffer on the stack and pass it
+     * on to RTSocketSgWrite.
+     */
+    Assert(cSegs <= 16);
+    PRTSGSEG paSegs = (PRTSGSEG)alloca(cSegs * sizeof(RTSGSEG));
+    AssertReturn(paSegs, VERR_NO_TMP_MEMORY);
+    for (size_t i = 0; i < cSegs; i++)
+    {
+        paSegs[i].pvSeg = va_arg(va, void *);
+        paSegs[i].cbSeg = va_arg(va, size_t);
+    }
+
+    RTSGBUF SgBuf;
+    RTSgBufInit(&SgBuf, paSegs, cSegs);
+    return RTSocketSgWriteNB(hSocket, &SgBuf, pcbWritten);
+}
+
+
+RTDECL(int) RTSocketSelectOne(RTSOCKET hSocket, RTMSINTERVAL cMillies)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+    int const fdMax = (int)pThis->hNative + 1;
+    AssertReturn((RTSOCKETNATIVE)(fdMax - 1) == pThis->hNative, VERR_INTERNAL_ERROR_5);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnselect, VERR_NET_NOT_UNSUPPORTED);
+# define select g_pfnselect
+#endif
+
+    /*
+     * Set up the file descriptor sets and do the select.
+     */
+    fd_set fdsetR;
+    FD_ZERO(&fdsetR);
+    FD_SET(pThis->hNative, &fdsetR);
+
+    fd_set fdsetE = fdsetR;
+
+    int rc;
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = select(fdMax, &fdsetR, NULL, &fdsetE, NULL);
+    else
+    {
+        struct timeval timeout;
+        timeout.tv_sec = cMillies / 1000;
+        timeout.tv_usec = (cMillies % 1000) * 1000;
+        rc = select(fdMax, &fdsetR, NULL, &fdsetE, &timeout);
+    }
+    if (rc > 0)
+        rc = VINF_SUCCESS;
+    else if (rc == 0)
+        rc = VERR_TIMEOUT;
+    else
+        rc = rtSocketError();
+
+#ifdef RT_OS_WINDOWS
+# undef select
+#endif
+    return rc;
+}
+
+
+/**
+ * Internal worker for RTSocketSelectOneEx and rtSocketPollCheck (fallback)
+ *
+ * @returns IPRT status code
+ * @param   pThis               The socket (valid).
+ * @param   fEvents             The events to select for.
+ * @param   pfEvents            Where to return the events.
+ * @param   cMillies            How long to select for, in milliseconds.
+ */
+static int rtSocketSelectOneEx(RTSOCKET pThis, uint32_t fEvents, uint32_t *pfEvents, RTMSINTERVAL cMillies)
+{
+    RTSOCKETNATIVE hNative = pThis->hNative;
+    if (hNative == NIL_RTSOCKETNATIVE)
+    {
+        /* Socket is already closed? Possible we raced someone calling rtSocketCloseIt.
+           Should we return a different status code? */
+        *pfEvents = RTSOCKET_EVT_ERROR;
+        return VINF_SUCCESS;
+    }
+
+    int const fdMax = (int)hNative + 1;
+    AssertReturn((RTSOCKETNATIVE)(fdMax - 1) == hNative, VERR_INTERNAL_ERROR_5);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnselect, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfn__WSAFDIsSet, VERR_NET_NOT_UNSUPPORTED);
+# define select         g_pfnselect
+# define __WSAFDIsSet   g_pfn__WSAFDIsSet
+#endif
+
+    *pfEvents = 0;
+
+    /*
+     * Set up the file descriptor sets and do the select.
+     */
+    fd_set fdsetR;
+    fd_set fdsetW;
+    fd_set fdsetE;
+    FD_ZERO(&fdsetR);
+    FD_ZERO(&fdsetW);
+    FD_ZERO(&fdsetE);
+
+    if (fEvents & RTSOCKET_EVT_READ)
+        FD_SET(hNative, &fdsetR);
+    if (fEvents & RTSOCKET_EVT_WRITE)
+        FD_SET(hNative, &fdsetW);
+    if (fEvents & RTSOCKET_EVT_ERROR)
+        FD_SET(hNative, &fdsetE);
+
+    int rc;
+    if (cMillies == RT_INDEFINITE_WAIT)
+        rc = select(fdMax, &fdsetR, &fdsetW, &fdsetE, NULL);
+    else
+    {
+        struct timeval timeout;
+        timeout.tv_sec = cMillies / 1000;
+        timeout.tv_usec = (cMillies % 1000) * 1000;
+        rc = select(fdMax, &fdsetR, &fdsetW, &fdsetE, &timeout);
+    }
+    if (rc > 0)
+    {
+        if (pThis->hNative == hNative)
+        {
+            if (FD_ISSET(hNative, &fdsetR))
+                *pfEvents |= RTSOCKET_EVT_READ;
+            if (FD_ISSET(hNative, &fdsetW))
+                *pfEvents |= RTSOCKET_EVT_WRITE;
+            if (FD_ISSET(hNative, &fdsetE))
+                *pfEvents |= RTSOCKET_EVT_ERROR;
+            rc = VINF_SUCCESS;
+        }
+        else
+        {
+            /* Socket was closed while we waited (rtSocketCloseIt).  Different status code? */
+            *pfEvents = RTSOCKET_EVT_ERROR;
+            rc = VINF_SUCCESS;
+        }
+    }
+    else if (rc == 0)
+        rc = VERR_TIMEOUT;
+    else
+        rc = rtSocketError();
+
+#ifdef RT_OS_WINDOWS
+# undef select
+# undef __WSAFDIsSet
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketSelectOneEx(RTSOCKET hSocket, uint32_t fEvents, uint32_t *pfEvents, RTMSINTERVAL cMillies)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfEvents, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fEvents & ~RTSOCKET_EVT_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+
+    return rtSocketSelectOneEx(pThis, fEvents, pfEvents, cMillies);
+}
+
+
+RTDECL(int) RTSocketShutdown(RTSOCKET hSocket, bool fRead, bool fWrite)
+{
+    /*
+     * Validate input, don't lock it because we might want to interrupt a call
+     * active on a different thread.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+    AssertReturn(fRead || fWrite, VERR_INVALID_PARAMETER);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnshutdown, VERR_NET_NOT_UNSUPPORTED);
+# define shutdown g_pfnshutdown
+#endif
+
+    /*
+     * Do the job.
+     */
+    int rc = VINF_SUCCESS;
+    int fHow;
+    if (fRead && fWrite)
+        fHow = SHUT_RDWR;
+    else if (fRead)
+        fHow = SHUT_RD;
+    else
+        fHow = SHUT_WR;
+    if (shutdown(pThis->hNative, fHow) == -1)
+        rc = rtSocketError();
+
+#ifdef RT_OS_WINDOWS
+# undef shutdown
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketGetLocalAddress(RTSOCKET hSocket, PRTNETADDR pAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfngetsockname, VERR_NET_NOT_UNSUPPORTED);
+# define getsockname g_pfngetsockname
+#endif
+
+    /*
+     * Get the address and convert it.
+     */
+    int             rc;
+    RTSOCKADDRUNION u;
+#ifdef RT_OS_WINDOWS
+    int             cbAddr = sizeof(u);
+#else
+    socklen_t       cbAddr = sizeof(u);
+#endif
+    RT_ZERO(u);
+    if (getsockname(pThis->hNative, &u.Addr, &cbAddr) == 0)
+        rc = rtSocketNetAddrFromAddr(&u, cbAddr, pAddr);
+    else
+        rc = rtSocketError();
+
+#ifdef RT_OS_WINDOWS
+# undef getsockname
+#endif
+    return rc;
+}
+
+
+RTDECL(int) RTSocketGetPeerAddress(RTSOCKET hSocket, PRTNETADDR pAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRefCount(pThis) >= (pThis->cUsers ? 2U : 1U), VERR_CALLER_NO_REFERENCE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfngetpeername, VERR_NET_NOT_UNSUPPORTED);
+# define getpeername g_pfngetpeername
+#endif
+
+    /*
+     * Get the address and convert it.
+     */
+    int             rc;
+    RTSOCKADDRUNION u;
+#ifdef RT_OS_WINDOWS
+    int             cbAddr = sizeof(u);
+#else
+    socklen_t       cbAddr = sizeof(u);
+#endif
+    RT_ZERO(u);
+    if (getpeername(pThis->hNative, &u.Addr, &cbAddr) == 0)
+        rc = rtSocketNetAddrFromAddr(&u, cbAddr, pAddr);
+    else
+        rc = rtSocketError();
+
+#ifdef RT_OS_WINDOWS
+# undef getpeername
+#endif
+    return rc;
+}
+
+
+
+/**
+ * Wrapper around bind.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   pAddr               The address to bind to.
+ */
+DECLHIDDEN(int) rtSocketBind(RTSOCKET hSocket, PCRTNETADDR pAddr)
+{
+    RTSOCKADDRUNION u;
+    int             cbAddr;
+    int rc = rtSocketAddrFromNetAddr(pAddr, &u, sizeof(u), &cbAddr);
+    if (RT_SUCCESS(rc))
+        rc = rtSocketBindRawAddr(hSocket, &u.Addr, cbAddr);
+    return rc;
+}
+
+
+/**
+ * Very thin wrapper around bind.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   pvAddr              The address to bind to (struct sockaddr and
+ *                              friends).
+ * @param   cbAddr              The size of the address.
+ */
+DECLHIDDEN(int) rtSocketBindRawAddr(RTSOCKET hSocket, void const *pvAddr, size_t cbAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvAddr, VERR_INVALID_POINTER);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnbind, VERR_NET_NOT_UNSUPPORTED);
+# define bind g_pfnbind
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc;
+    if (bind(pThis->hNative, (struct sockaddr const *)pvAddr, (int)cbAddr) == 0)
+        rc = VINF_SUCCESS;
+    else
+        rc = rtSocketError();
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef bind
+#endif
+    return rc;
+}
+
+
+
+/**
+ * Wrapper around listen.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   cMaxPending         The max number of pending connections.
+ */
+DECLHIDDEN(int) rtSocketListen(RTSOCKET hSocket, int cMaxPending)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnlisten, VERR_NET_NOT_UNSUPPORTED);
+# define listen g_pfnlisten
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = VINF_SUCCESS;
+    if (listen(pThis->hNative, cMaxPending) != 0)
+        rc = rtSocketError();
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef listen
+#endif
+    return rc;
+}
+
+
+/**
+ * Wrapper around accept.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   phClient            Where to return the client socket handle on
+ *                              success.
+ * @param   pAddr               Where to return the client address.
+ * @param   pcbAddr             On input this gives the size buffer size of what
+ *                              @a pAddr point to.  On return this contains the
+ *                              size of what's stored at @a pAddr.
+ */
+DECLHIDDEN(int) rtSocketAccept(RTSOCKET hSocket, PRTSOCKET phClient, struct sockaddr *pAddr, size_t *pcbAddr)
+{
+    /*
+     * Validate input.
+     * Only lock the socket temporarily while we get the native handle, so that
+     * we can safely shutdown and destroy the socket from a different thread.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnaccept, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnclosesocket, VERR_NET_NOT_UNSUPPORTED);
+# define accept g_pfnaccept
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    /*
+     * Call accept().
+     */
+    rtSocketErrorReset();
+    int         rc      = VINF_SUCCESS;
+#ifdef RT_OS_WINDOWS
+    int         cbAddr  = (int)*pcbAddr;
+#else
+    socklen_t   cbAddr  = *pcbAddr;
+#endif
+    RTSOCKETNATIVE hNativeClient = accept(pThis->hNative, pAddr, &cbAddr);
+    if (hNativeClient != NIL_RTSOCKETNATIVE)
+    {
+        *pcbAddr = cbAddr;
+
+        /*
+         * Wrap the client socket.
+         */
+        rc = rtSocketCreateForNative(phClient, hNativeClient, false /*fLeaveOpen*/);
+        if (RT_FAILURE(rc))
+        {
+#ifdef RT_OS_WINDOWS
+            g_pfnclosesocket(hNativeClient);
+#else
+            close(hNativeClient);
+#endif
+        }
+    }
+    else
+        rc = rtSocketError();
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef accept
+#endif
+    return rc;
+}
+
+
+/**
+ * Wrapper around connect.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   pAddr               The socket address to connect to.
+ * @param   cMillies            Number of milliseconds to wait for the connect attempt to complete.
+ *                              Use RT_INDEFINITE_WAIT to wait for ever.
+ *                              Use RT_TCPCLIENTCONNECT_DEFAULT_WAIT to wait for the default time
+ *                              configured on the running system.
+ */
+DECLHIDDEN(int) rtSocketConnect(RTSOCKET hSocket, PCRTNETADDR pAddr, RTMSINTERVAL cMillies)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnconnect, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfnselect, VERR_NET_NOT_UNSUPPORTED);
+    AssertReturn(g_pfngetsockopt, VERR_NET_NOT_UNSUPPORTED);
+# define connect        g_pfnconnect
+# define select         g_pfnselect
+# define getsockopt     g_pfngetsockopt
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    RTSOCKADDRUNION u;
+    int             cbAddr;
+    int rc = rtSocketAddrFromNetAddr(pAddr, &u, sizeof(u), &cbAddr);
+    if (RT_SUCCESS(rc))
+    {
+        if (cMillies == RT_SOCKETCONNECT_DEFAULT_WAIT)
+        {
+            if (connect(pThis->hNative, &u.Addr, cbAddr) != 0)
+                rc = rtSocketError();
+        }
+        else
+        {
+            /*
+             * Switch the socket to nonblocking mode, initiate the connect
+             * and wait for the socket to become writable or until the timeout
+             * expires.
+             */
+            rc = rtSocketSwitchBlockingMode(pThis, false /* fBlocking */);
+            if (RT_SUCCESS(rc))
+            {
+                if (connect(pThis->hNative, &u.Addr, cbAddr) != 0)
+                {
+                    rc = rtSocketError();
+                    if (rc == VERR_TRY_AGAIN || rc == VERR_NET_IN_PROGRESS)
+                    {
+                        int rcSock = 0;
+                        fd_set FdSetWriteable;
+                        struct timeval TvTimeout;
+
+                        TvTimeout.tv_sec = cMillies / RT_MS_1SEC;
+                        TvTimeout.tv_usec = (cMillies % RT_MS_1SEC) * RT_US_1MS;
+
+                        FD_ZERO(&FdSetWriteable);
+                        FD_SET(pThis->hNative, &FdSetWriteable);
+                        do
+                        {
+                            rcSock = select(pThis->hNative + 1, NULL, &FdSetWriteable, NULL,
+                                              cMillies == RT_INDEFINITE_WAIT || cMillies >= INT_MAX
+                                            ? NULL
+                                            : &TvTimeout);
+                            if (rcSock > 0)
+                            {
+                                int iSockError = 0;
+                                socklen_t cbSockOpt = sizeof(iSockError);
+                                rcSock = getsockopt(pThis->hNative, SOL_SOCKET, SO_ERROR, (char *)&iSockError, &cbSockOpt);
+                                if (rcSock == 0)
+                                {
+                                    if (iSockError == 0)
+                                        rc = VINF_SUCCESS;
+                                    else
+                                    {
+#ifdef RT_OS_WINDOWS
+                                        rc = RTErrConvertFromWin32(iSockError);
+#else
+                                        rc = RTErrConvertFromErrno(iSockError);
+#endif
+                                    }
+                                }
+                                else
+                                    rc = rtSocketError();
+                            }
+                            else if (rcSock == 0)
+                                rc = VERR_TIMEOUT;
+                            else
+                                rc = rtSocketError();
+                        } while (rc == VERR_INTERRUPTED);
+                    }
+                }
+
+                rtSocketSwitchBlockingMode(pThis, true /* fBlocking */);
+            }
+        }
+    }
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef connect
+# undef select
+# undef getsockopt
+#endif
+    return rc;
+}
+
+
+/**
+ * Wrapper around connect, raw address, no timeout.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   pvAddr              The raw socket address to connect to.
+ * @param   cbAddr              The size of the raw address.
+ */
+DECLHIDDEN(int) rtSocketConnectRaw(RTSOCKET hSocket, void const *pvAddr, size_t cbAddr)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnconnect, VERR_NET_NOT_UNSUPPORTED);
+# define connect        g_pfnconnect
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc;
+    if (connect(pThis->hNative, (const struct sockaddr *)pvAddr, (int)cbAddr) == 0)
+        rc = VINF_SUCCESS;
+    else
+        rc = rtSocketError();
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef connect
+#endif
+    return rc;
+}
+
+
+/**
+ * Wrapper around setsockopt.
+ *
+ * @returns IPRT status code.
+ * @param   hSocket             The socket handle.
+ * @param   iLevel              The protocol level, e.g. IPPORTO_TCP.
+ * @param   iOption             The option, e.g. TCP_NODELAY.
+ * @param   pvValue             The value buffer.
+ * @param   cbValue             The size of the value pointed to by pvValue.
+ */
+DECLHIDDEN(int) rtSocketSetOpt(RTSOCKET hSocket, int iLevel, int iOption, void const *pvValue, int cbValue)
+{
+    /*
+     * Validate input.
+     */
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(g_pfnsetsockopt, VERR_NET_NOT_UNSUPPORTED);
+# define setsockopt g_pfnsetsockopt
+#endif
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = VINF_SUCCESS;
+    if (setsockopt(pThis->hNative, iLevel, iOption, (const char *)pvValue, cbValue) != 0)
+        rc = rtSocketError();
+
+    rtSocketUnlock(pThis);
+#ifdef RT_OS_WINDOWS
+# undef setsockopt
+#endif
+    return rc;
+}
+
+
+/**
+ * Internal RTPollSetAdd helper that returns the handle that should be added to
+ * the pollset.
+ *
+ * @returns Valid handle on success, INVALID_HANDLE_VALUE on failure.
+ * @param   hSocket             The socket handle.
+ * @param   fEvents             The events we're polling for.
+ * @param   phNative            Where to put the primary handle.
+ */
+DECLHIDDEN(int) rtSocketPollGetHandle(RTSOCKET hSocket, uint32_t fEvents, PRTHCINTPTR phNative)
+{
+    RTSOCKETINT *pThis = hSocket;
+    RT_NOREF_PV(fEvents);
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, VERR_INVALID_HANDLE);
+#ifdef RT_OS_WINDOWS
+    AssertReturn(rtSocketTryLock(pThis), VERR_CONCURRENT_ACCESS);
+
+    int rc = VINF_SUCCESS;
+    if (pThis->hEvent != WSA_INVALID_EVENT)
+        *phNative = (RTHCINTPTR)pThis->hEvent;
+    else if (g_pfnWSACreateEvent)
+    {
+        pThis->hEvent = g_pfnWSACreateEvent();
+        *phNative = (RTHCINTPTR)pThis->hEvent;
+        if (pThis->hEvent == WSA_INVALID_EVENT)
+            rc = rtSocketError();
+    }
+    else
+    {
+        AssertCompile(WSA_INVALID_EVENT == (WSAEVENT)NULL);
+        pThis->hEvent = CreateEventW(NULL, TRUE /*fManualReset*/, FALSE /*fInitialState*/,  NULL /*pwszName*/);
+        *phNative = (RTHCINTPTR)pThis->hEvent;
+        if (pThis->hEvent == WSA_INVALID_EVENT)
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+
+    rtSocketUnlock(pThis);
+    return rc;
+
+#else  /* !RT_OS_WINDOWS */
+    *phNative = (RTHCUINTPTR)pThis->hNative;
+    return VINF_SUCCESS;
+#endif /* !RT_OS_WINDOWS */
+}
+
+#ifdef RT_OS_WINDOWS
+
+/**
+ * Fallback poller thread.
+ *
+ * @returns VINF_SUCCESS.
+ * @param   hSelf               The thread handle.
+ * @param   pvUser              Socket instance data.
+ */
+static DECLCALLBACK(int) rtSocketPollFallbackThreadProc(RTTHREAD hSelf, void *pvUser)
+{
+    RTSOCKETINT *pThis = (RTSOCKETINT *)pvUser;
+    RT_NOREF(hSelf);
+# define __WSAFDIsSet g_pfn__WSAFDIsSet
+
+    /*
+     * The execution loop.
+     */
+    while (!ASMAtomicReadBool(&pThis->fPollFallbackShutdown))
+    {
+        /*
+         * Do the selecting (with a 15 second timeout because that seems like a good idea).
+         */
+        struct fd_set SetRead;
+        struct fd_set SetWrite;
+        struct fd_set SetXcpt;
+
+        FD_ZERO(&SetRead);
+        FD_ZERO(&SetWrite);
+        FD_ZERO(&SetXcpt);
+
+        FD_SET(pThis->hPollFallbackNotifyR, &SetRead);
+        FD_SET(pThis->hPollFallbackNotifyR, &SetXcpt);
+
+        bool     fActive = ASMAtomicReadBool(&pThis->fPollFallbackActive);
+        uint32_t fEvents;
+        if (!fActive)
+            fEvents = 0;
+        else
+        {
+            fEvents = ASMAtomicReadU32(&pThis->fSubscribedEvts);
+            if (fEvents & RTPOLL_EVT_READ)
+                FD_SET(pThis->hNative, &SetRead);
+            if (fEvents & RTPOLL_EVT_WRITE)
+                FD_SET(pThis->hNative, &SetWrite);
+            if (fEvents & RTPOLL_EVT_ERROR)
+                FD_SET(pThis->hNative, &SetXcpt);
+        }
+
+        struct timeval Timeout;
+        Timeout.tv_sec  = 15;
+        Timeout.tv_usec = 0;
+        int rc = g_pfnselect(INT_MAX /*ignored*/, &SetRead, &SetWrite, &SetXcpt, &Timeout);
+
+        /* Stop immediately if told to shut down. */
+        if (ASMAtomicReadBool(&pThis->fPollFallbackShutdown))
+            break;
+
+        /*
+         * Process the result.
+         */
+        if (rc > 0)
+        {
+            /* First the socket we're listening on. */
+            if (   fEvents
+                && (   FD_ISSET(pThis->hNative, &SetRead)
+                    || FD_ISSET(pThis->hNative, &SetWrite)
+                    || FD_ISSET(pThis->hNative, &SetXcpt)) )
+            {
+                ASMAtomicWriteBool(&pThis->fPollFallbackActive, false);
+                SetEvent(pThis->hEvent);
+            }
+
+            /* Then maintain the notification pipe.  (We only read one byte here
+               because we're overly paranoid wrt socket switching to blocking mode.) */
+            if (FD_ISSET(pThis->hPollFallbackNotifyR, &SetRead))
+            {
+                char chIgnored;
+                g_pfnrecv(pThis->hPollFallbackNotifyR, &chIgnored, sizeof(chIgnored), MSG_NOSIGNAL);
+            }
+        }
+        else
+            AssertMsg(rc == 0, ("%Rrc\n", rtSocketError()));
+    }
+
+# undef __WSAFDIsSet
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Pokes the fallback thread, making sure it gets out of whatever it's stuck in.
+ *
+ * @param   pThis               The socket handle.
+ */
+static void rtSocketPokePollFallbackThread(RTSOCKETINT *pThis)
+{
+    Assert(pThis->fPollFallback);
+    if (pThis->hPollFallbackThread != NIL_RTTHREAD)
+    {
+        int cbWritten = g_pfnsend(pThis->hPollFallbackNotifyW, "!", 1, MSG_NOSIGNAL);
+        AssertMsg(cbWritten == 1, ("cbWritten=%d err=%Rrc\n",  rtSocketError()));
+        RT_NOREF_PV(cbWritten);
+    }
+}
+
+
+/**
+ * Called by rtSocketPollStart to make the thread start selecting on the socket.
+ *
+ * @returns 0 on success, RTPOLL_EVT_ERROR on failure.
+ * @param   pThis               The socket handle.
+ */
+static uint32_t rtSocketPollFallbackStart(RTSOCKETINT *pThis)
+{
+    /*
+     * Reset the event and tell the thread to start selecting on the socket.
+     */
+    ResetEvent(pThis->hEvent);
+    ASMAtomicWriteBool(&pThis->fPollFallbackActive, true);
+
+    /*
+     * Wake up the thread the thread.
+     */
+    if (pThis->hPollFallbackThread != NIL_RTTHREAD)
+        rtSocketPokePollFallbackThread(pThis);
+    else
+    {
+        /*
+         * Not running, need to set it up and start it.
+         */
+        AssertLogRelReturn(pThis->hEvent != NULL && pThis->hEvent != INVALID_HANDLE_VALUE, RTPOLL_EVT_ERROR);
+
+        /* Create the notification socket pair. */
+        int rc;
+        if (pThis->hPollFallbackNotifyR == NIL_RTSOCKETNATIVE)
+        {
+            rc = rtSocketCreateNativeTcpPair(&pThis->hPollFallbackNotifyW, &pThis->hPollFallbackNotifyR);
+            AssertLogRelRCReturn(rc, RTPOLL_EVT_ERROR);
+
+            /* Make the read end non-blocking (not fatal). */
+            u_long fNonBlocking = 1;
+            rc = g_pfnioctlsocket(pThis->hPollFallbackNotifyR, FIONBIO, &fNonBlocking);
+            AssertLogRelMsg(rc == 0,  ("rc=%#x %Rrc\n", rc, rtSocketError()));
+        }
+
+        /* Finally, start the thread.  ASSUME we don't need too much stack. */
+        rc = RTThreadCreate(&pThis->hPollFallbackThread, rtSocketPollFallbackThreadProc, pThis,
+                            _128K, RTTHREADTYPE_IO, RTTHREADFLAGS_WAITABLE, "sockpoll");
+        AssertLogRelRCReturn(rc, RTPOLL_EVT_ERROR);
+    }
+    return 0;
+}
+
+
+/**
+ * Undos the harm done by WSAEventSelect.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The socket handle.
+ */
+static int rtSocketPollClearEventAndRestoreBlocking(RTSOCKETINT *pThis)
+{
+    int rc = VINF_SUCCESS;
+    if (pThis->fSubscribedEvts)
+    {
+        if (!pThis->fPollFallback)
+        {
+            Assert(g_pfnWSAEventSelect && g_pfnioctlsocket);
+            if (g_pfnWSAEventSelect && g_pfnioctlsocket)
+            {
+                if (g_pfnWSAEventSelect(pThis->hNative, WSA_INVALID_EVENT, 0) == 0)
+                {
+                    pThis->fSubscribedEvts = 0;
+
+                    /*
+                     * Switch back to blocking mode if that was the state before the
+                     * operation.
+                     */
+                    if (pThis->fBlocking)
+                    {
+                        u_long fNonBlocking = 0;
+                        int rc2 = g_pfnioctlsocket(pThis->hNative, FIONBIO, &fNonBlocking);
+                        if (rc2 != 0)
+                        {
+                            rc = rtSocketError();
+                            AssertMsgFailed(("%Rrc; rc2=%d\n", rc, rc2));
+                        }
+                    }
+                }
+                else
+                {
+                    rc = rtSocketError();
+                    AssertMsgFailed(("%Rrc\n", rc));
+                }
+            }
+            else
+            {
+                Assert(pThis->fPollFallback);
+                rc = VINF_SUCCESS;
+            }
+        }
+        /*
+         * Just clear the event mask as we never started waiting if we get here.
+         */
+        else
+            ASMAtomicWriteU32(&pThis->fSubscribedEvts, 0);
+    }
+    return rc;
+}
+
+
+/**
+ * Updates the mask of events we're subscribing to.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The socket handle.
+ * @param   fEvents             The events we want to subscribe to.
+ */
+static int rtSocketPollUpdateEvents(RTSOCKETINT *pThis, uint32_t fEvents)
+{
+    if (!pThis->fPollFallback)
+    {
+        LONG fNetworkEvents = 0;
+        if (fEvents & RTPOLL_EVT_READ)
+            fNetworkEvents |= FD_READ;
+        if (fEvents & RTPOLL_EVT_WRITE)
+            fNetworkEvents |= FD_WRITE;
+        if (fEvents & RTPOLL_EVT_ERROR)
+            fNetworkEvents |= FD_CLOSE;
+        LogFlowFunc(("fNetworkEvents=%#x\n", fNetworkEvents));
+
+        if (g_pfnWSAEventSelect(pThis->hNative, pThis->hEvent, fNetworkEvents) == 0)
+        {
+            pThis->fSubscribedEvts = fEvents;
+            return VINF_SUCCESS;
+        }
+
+        int rc = rtSocketError();
+        AssertMsgFailed(("fNetworkEvents=%#x rc=%Rrc\n", fNetworkEvents, rtSocketError()));
+        return rc;
+    }
+
+    /*
+     * Update the events we're waiting for.  Caller will poke/start the thread. later
+     */
+    ASMAtomicWriteU32(&pThis->fSubscribedEvts, fEvents);
+    return VINF_SUCCESS;
+}
+
+#endif  /* RT_OS_WINDOWS */
+
+
+#if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+
+/**
+ * Checks for pending events.
+ *
+ * @returns Event mask or 0.
+ * @param   pThis               The socket handle.
+ * @param   fEvents             The desired events.
+ */
+static uint32_t rtSocketPollCheck(RTSOCKETINT *pThis, uint32_t fEvents)
+{
+    uint32_t fRetEvents = 0;
+
+    LogFlowFunc(("pThis=%#p fEvents=%#x\n", pThis, fEvents));
+
+# ifdef RT_OS_WINDOWS
+    /* Make sure WSAEnumNetworkEvents returns what we want. */
+    int rc = VINF_SUCCESS;
+    if ((pThis->fSubscribedEvts & fEvents) != fEvents)
+        rc = rtSocketPollUpdateEvents(pThis, pThis->fSubscribedEvts | fEvents);
+
+    if (!pThis->fPollFallback)
+    {
+        /* Atomically get pending events and reset the event semaphore. */
+        Assert(g_pfnWSAEnumNetworkEvents);
+        WSANETWORKEVENTS NetEvts;
+        RT_ZERO(NetEvts);
+        if (g_pfnWSAEnumNetworkEvents(pThis->hNative, pThis->hEvent, &NetEvts) == 0)
+        {
+            if (   (NetEvts.lNetworkEvents & FD_READ)
+                && NetEvts.iErrorCode[FD_READ_BIT] == 0)
+                fRetEvents |= RTPOLL_EVT_READ;
+
+            if (   (NetEvts.lNetworkEvents & FD_WRITE)
+                && NetEvts.iErrorCode[FD_WRITE_BIT] == 0)
+                fRetEvents |= RTPOLL_EVT_WRITE;
+
+            if (NetEvts.lNetworkEvents & FD_CLOSE)
+                fRetEvents |= RTPOLL_EVT_ERROR;
+            else
+                for (uint32_t i = 0; i < FD_MAX_EVENTS; i++)
+                    if (   (NetEvts.lNetworkEvents & (1L << i))
+                        && NetEvts.iErrorCode[i] != 0)
+                        fRetEvents |= RTPOLL_EVT_ERROR;
+
+            pThis->fEventsSaved = fRetEvents |= pThis->fEventsSaved;
+            fRetEvents &= fEvents | RTPOLL_EVT_ERROR;
+        }
+        else
+            rc = rtSocketError();
+    }
+
+    /* Fall back on select if we hit an error above or is using fallback polling. */
+    if (pThis->fPollFallback || RT_FAILURE(rc))
+    {
+        rc = rtSocketSelectOneEx(pThis, fEvents & RTPOLL_EVT_ERROR ? fEvents | RTPOLL_EVT_READ : fEvents, &fRetEvents, 0);
+        if (RT_SUCCESS(rc))
+        {
+            /* rtSocketSelectOneEx may return RTPOLL_EVT_READ on disconnect.  Use
+               getpeername to fix this. */
+            if ((fRetEvents & (RTPOLL_EVT_READ | RTPOLL_EVT_ERROR)) == RTPOLL_EVT_READ)
+            {
+# if 0 /* doens't work */
+                rtSocketErrorReset();
+                char chIgn;
+                rc = g_pfnrecv(pThis->hNative, &chIgn, 0, MSG_NOSIGNAL);
+                rc = rtSocketError();
+                if (RT_FAILURE(rc))
+                    fRetEvents |= RTPOLL_EVT_ERROR;
+
+                rc = g_pfnsend(pThis->hNative, &chIgn, 0, MSG_NOSIGNAL);
+                rc = rtSocketError();
+                if (RT_FAILURE(rc))
+                    fRetEvents |= RTPOLL_EVT_ERROR;
+
+                RTSOCKADDRUNION u;
+                int cbAddr = sizeof(u);
+                if (g_pfngetpeername(pThis->hNative, &u.Addr, &cbAddr) == SOCKET_ERROR)
+                    fRetEvents |= RTPOLL_EVT_ERROR;
+# endif
+                /* If no bytes are available, assume error condition. */
+                u_long cbAvail = 0;
+                rc = g_pfnioctlsocket(pThis->hNative, FIONREAD, &cbAvail);
+                if (rc == 0 && cbAvail == 0)
+                    fRetEvents |= RTPOLL_EVT_ERROR;
+            }
+            fRetEvents &= fEvents | RTPOLL_EVT_ERROR;
+        }
+        else if (rc == VERR_TIMEOUT)
+            fRetEvents = 0;
+        else
+            fRetEvents |= RTPOLL_EVT_ERROR;
+    }
+
+# else  /* RT_OS_OS2 */
+    int aFds[4] = { pThis->hNative, pThis->hNative, pThis->hNative, -1 };
+    int rc = os2_select(aFds, 1, 1, 1, 0);
+    if (rc > 0)
+    {
+        if (aFds[0] == pThis->hNative)
+            fRetEvents |= RTPOLL_EVT_READ;
+        if (aFds[1] == pThis->hNative)
+            fRetEvents |= RTPOLL_EVT_WRITE;
+        if (aFds[2] == pThis->hNative)
+            fRetEvents |= RTPOLL_EVT_ERROR;
+        fRetEvents &= fEvents;
+    }
+# endif /* RT_OS_OS2 */
+
+    LogFlowFunc(("fRetEvents=%#x\n", fRetEvents));
+    return fRetEvents;
+}
+
+
+/**
+ * Internal RTPoll helper that polls the socket handle and, if @a fNoWait is
+ * clear, starts whatever actions we've got running during the poll call.
+ *
+ * @returns 0 if no pending events, actions initiated if @a fNoWait is clear.
+ *          Event mask (in @a fEvents) and no actions if the handle is ready
+ *          already.
+ *          UINT32_MAX (asserted) if the socket handle is busy in I/O or a
+ *          different poll set.
+ *
+ * @param   hSocket             The socket handle.
+ * @param   hPollSet            The poll set handle (for access checks).
+ * @param   fEvents             The events we're polling for.
+ * @param   fFinalEntry         Set if this is the final entry for this handle
+ *                              in this poll set.  This can be used for dealing
+ *                              with duplicate entries.
+ * @param   fNoWait             Set if it's a zero-wait poll call.  Clear if
+ *                              we'll wait for an event to occur.
+ *
+ * @remarks There is a potential race wrt duplicate handles when @a fNoWait is
+ *          @c true, we don't currently care about that oddity...
+ */
+DECLHIDDEN(uint32_t) rtSocketPollStart(RTSOCKET hSocket, RTPOLLSET hPollSet, uint32_t fEvents, bool fFinalEntry, bool fNoWait)
+{
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, UINT32_MAX);
+    /** @todo This isn't quite sane. Replace by critsect and open up concurrent
+     *        reads and writes! */
+    if (rtSocketTryLock(pThis))
+        pThis->hPollSet = hPollSet;
+    else
+    {
+        AssertReturn(pThis->hPollSet == hPollSet, UINT32_MAX);
+        ASMAtomicIncU32(&pThis->cUsers);
+    }
+
+    /* (rtSocketPollCheck will reset the event object). */
+# ifdef RT_OS_WINDOWS
+    uint32_t fRetEvents = pThis->fEventsSaved;
+    pThis->fEventsSaved = 0; /* Reset */
+    fRetEvents |= rtSocketPollCheck(pThis, fEvents);
+
+    if (   !fRetEvents
+        && !fNoWait)
+    {
+        pThis->fPollEvts |= fEvents;
+        if (fFinalEntry)
+        {
+            if (pThis->fSubscribedEvts != pThis->fPollEvts)
+            {
+                /** @todo seems like there might be a call to many here and that fPollEvts is
+                 *        totally unnecessary... (bird) */
+                int rc = rtSocketPollUpdateEvents(pThis, pThis->fPollEvts);
+                if (RT_FAILURE(rc))
+                {
+                    pThis->fPollEvts = 0;
+                    fRetEvents       = UINT32_MAX;
+                }
+            }
+
+            /* Make sure we don't block when there are events pending relevant to an earlier poll set entry. */
+            if (pThis->fEventsSaved && !pThis->fPollFallback && g_pfnWSASetEvent && fRetEvents == 0)
+                g_pfnWSASetEvent(pThis->hEvent);
+        }
+    }
+# else
+    uint32_t fRetEvents = rtSocketPollCheck(pThis, fEvents);
+# endif
+
+    if (fRetEvents || fNoWait)
+    {
+        if (pThis->cUsers == 1)
+        {
+# ifdef RT_OS_WINDOWS
+            pThis->fEventsSaved    &= RTPOLL_EVT_ERROR;
+            pThis->fHarvestedEvents = false;
+            rtSocketPollClearEventAndRestoreBlocking(pThis);
+# endif
+            pThis->hPollSet = NIL_RTPOLLSET;
+        }
+# ifdef RT_OS_WINDOWS
+        else
+            pThis->fHarvestedEvents = true;
+# endif
+        ASMAtomicDecU32(&pThis->cUsers);
+    }
+# ifdef RT_OS_WINDOWS
+    /*
+     * Kick the poller thread on if this is the final entry and we're in
+     * winsock 1.x fallback mode.
+     */
+    else if (pThis->fPollFallback && fFinalEntry)
+        fRetEvents = rtSocketPollFallbackStart(pThis);
+# endif
+
+    return fRetEvents;
+}
+
+
+/**
+ * Called after a WaitForMultipleObjects returned in order to check for pending
+ * events and stop whatever actions that rtSocketPollStart() initiated.
+ *
+ * @returns Event mask or 0.
+ *
+ * @param   hSocket             The socket handle.
+ * @param   fEvents             The events we're polling for.
+ * @param   fFinalEntry         Set if this is the final entry for this handle
+ *                              in this poll set.  This can be used for dealing
+ *                              with duplicate entries.  Only keep in mind that
+ *                              this method is called in reverse order, so the
+ *                              first call will have this set (when the entire
+ *                              set was processed).
+ * @param   fHarvestEvents      Set if we should check for pending events.
+ */
+DECLHIDDEN(uint32_t) rtSocketPollDone(RTSOCKET hSocket, uint32_t fEvents, bool fFinalEntry, bool fHarvestEvents)
+{
+    RTSOCKETINT *pThis = hSocket;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTSOCKET_MAGIC, 0);
+    Assert(pThis->cUsers > 0);
+    Assert(pThis->hPollSet != NIL_RTPOLLSET);
+    RT_NOREF_PV(fFinalEntry);
+
+# ifdef RT_OS_WINDOWS
+    /*
+     * Deactivate the poll thread if we're in winsock 1.x fallback poll mode.
+     */
+    if (   pThis->fPollFallback
+        && pThis->hPollFallbackThread != NIL_RTTHREAD)
+    {
+        ASMAtomicWriteU32(&pThis->fSubscribedEvts, 0);
+        if (ASMAtomicXchgBool(&pThis->fPollFallbackActive, false))
+            rtSocketPokePollFallbackThread(pThis);
+    }
+# endif
+
+    /*
+     * Harvest events and clear the event mask for the next round of polling.
+     */
+    uint32_t fRetEvents;
+# ifdef RT_OS_WINDOWS
+    if (!pThis->fPollFallback)
+    {
+        if (!pThis->fHarvestedEvents)
+        {
+            fRetEvents = rtSocketPollCheck(pThis, fEvents);
+            pThis->fHarvestedEvents = true;
+        }
+        else
+            fRetEvents = pThis->fEventsSaved;
+        if (fHarvestEvents)
+            fRetEvents &= fEvents;
+        else
+            fRetEvents = 0;
+        pThis->fPollEvts = 0;
+    }
+    else
+# endif
+    {
+        if (fHarvestEvents)
+            fRetEvents = rtSocketPollCheck(pThis, fEvents);
+        else
+            fRetEvents = 0;
+    }
+
+    /*
+     * Make the socket blocking again and unlock the handle.
+     */
+    if (pThis->cUsers == 1)
+    {
+# ifdef RT_OS_WINDOWS
+        pThis->fEventsSaved    &= RTPOLL_EVT_ERROR;
+        pThis->fHarvestedEvents = false;
+        rtSocketPollClearEventAndRestoreBlocking(pThis);
+# endif
+        pThis->hPollSet = NIL_RTPOLLSET;
+    }
+    ASMAtomicDecU32(&pThis->cUsers);
+    return fRetEvents;
+}
+
+#endif /* RT_OS_WINDOWS || RT_OS_OS2 */
+
diff --git a/src/VBox/Runtime/r3/solaris/Makefile.kup b/src/VBox/Runtime/r3/solaris/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/Makefile.kup
diff --git a/src/VBox/Runtime/r3/solaris/RTFileQuerySectorSize-solaris.cpp b/src/VBox/Runtime/r3/solaris/RTFileQuerySectorSize-solaris.cpp
new file mode 100644
index 00000000..4620b71c
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/RTFileQuerySectorSize-solaris.cpp
@@ -0,0 +1,90 @@
+/* $Id: RTFileQuerySectorSize-solaris.cpp $ */
+/** @file
+ * IPRT - RTFileQuerySectorSize, Solaris.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+
+#include <errno.h>
+#include <stropts.h>
+#include <sys/types.h>
+#include <sys/dkio.h>
+#include <sys/vtoc.h>
+#include <sys/stat.h>
+
+
+
+RTDECL(int) RTFileQuerySectorSize(RTFILE hFile, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pcbSector, VERR_INVALID_PARAMETER);
+
+    int rc;
+    int const fd = (int)RTFileToNative(hFile);
+    struct stat DevStat = { 0 };
+    if (!fstat(fd, &DevStat))
+    {
+        if (S_ISBLK(DevStat.st_mode) || S_ISCHR(DevStat.st_mode))
+        {
+            struct dk_minfo MediaInfo;
+            if (!ioctl(fd, DKIOCGMEDIAINFO, &MediaInfo))
+            {
+                AssertReturn(MediaInfo.dki_lbsize > 0, VERR_INVALID_FUNCTION);
+                *pcbSector = MediaInfo.dki_lbsize;
+                return VINF_SUCCESS;
+            }
+            rc = RTErrConvertFromErrno(errno);
+            AssertMsgFailed(("ioctl failed: errno=%d / %Rrc\n", errno, rc));
+        }
+        else
+        {
+            AssertMsgFailed(("not a block or character device.\n"));
+            rc = VERR_INVALID_FUNCTION;
+        }
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(errno);
+        AssertMsgFailed(("fstat failed: errno=%d / %Rrc\n", errno, rc));
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/RTSystemFirmware-solaris.cpp b/src/VBox/Runtime/r3/solaris/RTSystemFirmware-solaris.cpp
new file mode 100644
index 00000000..d986e9f2
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/RTSystemFirmware-solaris.cpp
@@ -0,0 +1,78 @@
+/* $Id: RTSystemFirmware-solaris.cpp $ */
+/** @file
+ * IPRT - System firmware information for Solaris.
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/system.h>
+#include <iprt/errcore.h>
+
+#include <libdevinfo.h>
+
+
+RTDECL(int) RTSystemQueryFirmwareType(PRTSYSFWTYPE penmFirmwareType)
+{
+    di_node_t di_node;
+    di_node = di_init("/", DINFOSUBTREE|DINFOPROP);
+    if (di_node == DI_NODE_NIL)
+    {
+        *penmFirmwareType = RTSYSFWTYPE_INVALID;
+        return VERR_NOT_SUPPORTED;
+    }
+
+    int64_t *efiprop;
+    int rc = di_prop_lookup_int64(DDI_DEV_T_ANY, di_node, "efi-systab", &efiprop);
+    if (rc == -1)
+        *penmFirmwareType = RTSYSFWTYPE_BIOS;
+    else
+        *penmFirmwareType = RTSYSFWTYPE_UEFI;
+
+    di_fini(di_node);
+
+    return VINF_SUCCESS;
+}
+RT_EXPORT_SYMBOL(RTSystemQueryFirmwareType);
+
+
+RTDECL(int) RTSystemQueryFirmwareBoolean(RTSYSFWBOOL enmBoolean, bool *pfValue)
+{
+    RT_NOREF(enmBoolean, pfValue);
+    return VERR_NOT_SUPPORTED;
+}
+RT_EXPORT_SYMBOL(RTSystemQueryFirmwareBoolean);
+
diff --git a/src/VBox/Runtime/r3/solaris/RTSystemQueryDmiString-solaris.cpp b/src/VBox/Runtime/r3/solaris/RTSystemQueryDmiString-solaris.cpp
new file mode 100644
index 00000000..8e62a7a0
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/RTSystemQueryDmiString-solaris.cpp
@@ -0,0 +1,117 @@
+/* $Id: RTSystemQueryDmiString-solaris.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryDmiString, solaris ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+#include <smbios.h>
+#include <errno.h>
+
+
+RTDECL(int) RTSystemQueryDmiString(RTSYSDMISTR enmString, char *pszBuf, size_t cbBuf)
+{
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbBuf > 0, VERR_INVALID_PARAMETER);
+    *pszBuf = '\0';
+    AssertReturn(enmString > RTSYSDMISTR_INVALID && enmString < RTSYSDMISTR_END, VERR_INVALID_PARAMETER);
+
+    int rc = VERR_NOT_SUPPORTED;
+    int err = 0;
+    smbios_hdl_t *pSMB = smbios_open(NULL /* default fd */, SMB_VERSION, 0 /* flags */, &err);
+    if (pSMB)
+    {
+        smbios_system_t hSMBSys;
+        id_t hSMBId = smbios_info_system(pSMB, &hSMBSys);
+        if (hSMBId != SMB_ERR)
+        {
+            /* Don't need the common bits for the product UUID. */
+            if (enmString == RTSYSDMISTR_PRODUCT_UUID)
+            {
+                static char const s_szHex[17] = "0123456789ABCDEF";
+                char     szData[64];
+                char    *pszData = szData;
+                unsigned cchUuid = RT_MIN(hSMBSys.smbs_uuidlen, sizeof(szData) - 1);
+                for (unsigned i = 0; i < cchUuid; i++)
+                {
+                    *pszData++ = s_szHex[hSMBSys.smbs_uuid[i] >> 4];
+                    *pszData++ = s_szHex[hSMBSys.smbs_uuid[i] & 0xf];
+                    if (i == 3 || i == 5 || i == 7 || i == 9)
+                        *pszData++ = '-';
+                }
+                *pszData = '\0';
+                rc = RTStrCopy(pszBuf, cbBuf, szData);
+                smbios_close(pSMB);
+                return rc;
+            }
+
+            smbios_info_t hSMBInfo;
+            id_t hSMBInfoId = smbios_info_common(pSMB, hSMBId, &hSMBInfo);
+            if (hSMBInfoId != SMB_ERR)
+            {
+                switch (enmString)
+                {
+                    case RTSYSDMISTR_PRODUCT_NAME:      rc = RTStrCopy(pszBuf, cbBuf, hSMBInfo.smbi_product); break;
+                    case RTSYSDMISTR_PRODUCT_VERSION:   rc = RTStrCopy(pszBuf, cbBuf, hSMBInfo.smbi_version); break;
+                    case RTSYSDMISTR_PRODUCT_SERIAL:    rc = RTStrCopy(pszBuf, cbBuf, hSMBInfo.smbi_serial);  break;
+                    case RTSYSDMISTR_MANUFACTURER:      rc = RTStrCopy(pszBuf, cbBuf, hSMBInfo.smbi_manufacturer);  break;
+
+                    default:  /* make gcc happy */
+                        rc = VERR_NOT_SUPPORTED;
+                }
+                smbios_close(pSMB);
+                return rc;
+            }
+        }
+
+        /* smbios_* error path. */
+        err = smbios_errno(pSMB);
+        smbios_close(pSMB);
+    }
+
+    /* Do some error conversion.  */
+    if (err == EPERM || err == EACCES)
+        rc = VERR_ACCESS_DENIED;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/RTSystemShutdown-solaris.cpp b/src/VBox/Runtime/r3/solaris/RTSystemShutdown-solaris.cpp
new file mode 100644
index 00000000..163b608f
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/RTSystemShutdown-solaris.cpp
@@ -0,0 +1,112 @@
+/* $Id: RTSystemShutdown-solaris.cpp $ */
+/** @file
+ * IPRT - RTSystemShutdown, linux implementation.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/process.h>
+#include <iprt/string.h>
+
+
+RTDECL(int) RTSystemShutdown(RTMSINTERVAL cMsDelay, uint32_t fFlags, const char *pszLogMsg)
+{
+    AssertPtrReturn(pszLogMsg, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTSYSTEM_SHUTDOWN_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Assemble the argument vector.
+     */
+    int         iArg = 0;
+    const char *apszArgs[8];
+
+    RT_BZERO(apszArgs, sizeof(apszArgs));
+
+    apszArgs[iArg++] = "/usr/sbin/shutdown";
+    apszArgs[iArg++] = "-y"; /* Pre-answer confirmation question. */
+    apszArgs[iArg++] = "-i"; /* Change to the following state. */
+    switch (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK)
+    {
+        case RTSYSTEM_SHUTDOWN_HALT:
+            apszArgs[iArg++] = "0";
+            break;
+        case RTSYSTEM_SHUTDOWN_REBOOT:
+            apszArgs[iArg++] = "6";
+            break;
+        case RTSYSTEM_SHUTDOWN_POWER_OFF:
+        case RTSYSTEM_SHUTDOWN_POWER_OFF_HALT:
+            apszArgs[iArg++] = "5";
+            break;
+    }
+
+    apszArgs[iArg++] = "-g"; /* Grace period. */
+
+    char szWhen[80];
+    if (cMsDelay < 500)
+        strcpy(szWhen, "0");
+    else
+        RTStrPrintf(szWhen, sizeof(szWhen), "%u", (unsigned)((cMsDelay + 499) / 1000));
+    apszArgs[iArg++] = szWhen;
+
+    apszArgs[iArg++] = pszLogMsg;
+
+
+    /*
+     * Start the shutdown process and wait for it to complete.
+     */
+    RTPROCESS hProc;
+    int rc = RTProcCreate(apszArgs[0], apszArgs, RTENV_DEFAULT, 0 /*fFlags*/, &hProc);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    RTPROCSTATUS ProcStatus;
+    rc = RTProcWait(hProc, RTPROCWAIT_FLAGS_BLOCK, &ProcStatus);
+    if (RT_SUCCESS(rc))
+    {
+        if (   ProcStatus.enmReason != RTPROCEXITREASON_NORMAL
+            || ProcStatus.iStatus   != 0)
+            rc = VERR_SYS_SHUTDOWN_FAILED;
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/coredumper-solaris.cpp b/src/VBox/Runtime/r3/solaris/coredumper-solaris.cpp
new file mode 100644
index 00000000..d1a24b2c
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/coredumper-solaris.cpp
@@ -0,0 +1,2375 @@
+/* $Id: coredumper-solaris.cpp $ */
+/** @file
+ * IPRT - Custom Core Dumper, Solaris.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/coredumper.h>
+
+#include <iprt/asm.h>
+#include <iprt/dir.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/process.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include "coredumper-solaris.h"
+
+#ifdef RT_OS_SOLARIS
+# include <syslog.h>
+# include <signal.h>
+# include <stdlib.h>
+# include <unistd.h>
+# include <errno.h>
+# include <zone.h>
+# include <sys/proc.h>
+# include <sys/sysmacros.h>
+# include <sys/systeminfo.h>
+# include <sys/mman.h>
+# include <sys/types.h>
+# include <sys/stat.h>
+# include <fcntl.h>
+# include <ucontext.h>
+#endif  /* RT_OS_SOLARIS */
+
+#include <iprt/formats/elf.h>
+#include <iprt/formats/elf64.h>
+
+
+/*********************************************************************************************************************************
+*   Globals                                                                                                                      *
+*********************************************************************************************************************************/
+static RTNATIVETHREAD volatile  g_CoreDumpThread             = NIL_RTNATIVETHREAD;
+static bool volatile            g_fCoreDumpSignalSetup       = false;
+static uint32_t volatile        g_fCoreDumpFlags             = 0;
+static char                     g_szCoreDumpDir[PATH_MAX]    = { 0 };
+static char                     g_szCoreDumpFile[PATH_MAX]   = { 0 };
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#define CORELOG_NAME        "CoreDumper: "
+#define CORELOG(a)          Log(a)
+#define CORELOGRELSYS(a)       \
+    do { \
+        rtCoreDumperSysLogWrapper a; \
+    } while (0)
+
+
+/**
+ * ELFNOTEHDR: ELF NOTE header.
+ */
+typedef struct ELFNOTEHDR
+{
+    Elf64_Nhdr                      Hdr;                        /* Header of NOTE section */
+    char                            achName[8];                 /* Name of NOTE section */
+} ELFNOTEHDR;
+typedef ELFNOTEHDR *PELFNOTEHDR;
+
+/**
+ * Wrapper function to write IPRT format style string to the syslog.
+ *
+ * @param pszFormat         Format string
+ */
+static void rtCoreDumperSysLogWrapper(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    char szBuf[1024];
+    RTStrPrintfV(szBuf, sizeof(szBuf), pszFormat, va);
+    va_end(va);
+    syslog(LOG_ERR, "%s", szBuf);
+}
+
+
+/**
+ * Determines endianness of the system. Just for completeness.
+ *
+ * @return Will return false if system is little endian, true otherwise.
+ */
+static bool IsBigEndian()
+{
+    const int i = 1;
+    char *p = (char *)&i;
+    if (p[0] == 1)
+        return false;
+    return true;
+}
+
+
+/**
+ * Reads from a file making sure an interruption doesn't cause a failure.
+ *
+ * @param fd                Handle to the file to read.
+ * @param pv                Where to store the read data.
+ * @param cbToRead          Size of data to read.
+ *
+ * @return IPRT status code.
+ */
+static int ReadFileNoIntr(int fd, void *pv, size_t cbToRead)
+{
+    for (;;)
+    {
+        ssize_t cbRead = read(fd, pv, cbToRead);
+        if (cbRead < 0)
+        {
+            if (errno == EINTR)
+                continue;
+            return RTErrConvertFromErrno(errno);
+        }
+        if ((size_t)cbRead == cbToRead)
+            return VINF_SUCCESS;
+        if ((size_t)cbRead > cbToRead)
+            return VERR_INTERNAL_ERROR_3;
+        if (cbRead == 0)
+            return VERR_EOF;
+        pv = (uint8_t *)pv + cbRead;
+        cbToRead -= cbRead;
+    }
+}
+
+
+/**
+ * Writes to a file making sure an interruption doesn't cause a failure.
+ *
+ * @param fd                Handle to the file to write to.
+ * @param pv                Pointer to what to write.
+ * @param cbToWrite         Size of data to write.
+ *
+ * @return IPRT status code.
+ */
+static int WriteFileNoIntr(int fd, const void *pv, size_t cbToWrite)
+{
+    for (;;)
+    {
+        ssize_t cbWritten = write(fd, pv, cbToWrite);
+        if (cbWritten < 0)
+        {
+            if (errno == EINTR)
+                continue;
+            return RTErrConvertFromErrno(errno);
+        }
+        if ((size_t)cbWritten == cbToWrite)
+            return VINF_SUCCESS;
+        if ((size_t)cbWritten > cbToWrite)
+            return VERR_INTERNAL_ERROR_2;
+        pv = (uint8_t const *)pv + cbWritten;
+        cbToWrite -= cbWritten;
+    }
+}
+
+
+/**
+ * Read from a given offset in the process' address space.
+ *
+ * @param pSolProc         Pointer to the solaris process.
+ * @param off              The offset to read from.
+ * @param pvBuf            Where to read the data into.
+ * @param cbToRead         Number of bytes to read.
+ *
+ * @return VINF_SUCCESS, if all the given bytes was read in, otherwise VERR_READ_ERROR.
+ */
+static ssize_t ProcReadAddrSpace(PRTSOLCOREPROCESS pSolProc, RTFOFF off, void *pvBuf, size_t cbToRead)
+{
+    for (;;)
+    {
+        ssize_t cbRead = pread(pSolProc->fdAs, pvBuf, cbToRead, off);
+        if (cbRead < 0)
+        {
+            if (errno == EINTR)
+                continue;
+            return RTErrConvertFromErrno(errno);
+        }
+        if ((size_t)cbRead == cbToRead)
+            return VINF_SUCCESS;
+        if ((size_t)cbRead > cbToRead)
+            return VERR_INTERNAL_ERROR_4;
+        if (cbRead == 0)
+            return VERR_EOF;
+
+        pvBuf     = (uint8_t *)pvBuf + cbRead;
+        cbToRead -= cbRead;
+        off      += cbRead;
+    }
+}
+
+
+/**
+ * Determines if the current process' architecture is suitable for dumping core.
+ *
+ * @param pSolProc         Pointer to the solaris process.
+ *
+ * @return true if the architecture matches the current one.
+ */
+static inline bool IsProcessArchNative(PRTSOLCOREPROCESS pSolProc)
+{
+    psinfo_t *pProcInfo = (psinfo_t *)pSolProc->pvProcInfo;
+    return pProcInfo->pr_dmodel == PR_MODEL_NATIVE;
+}
+
+
+/**
+ * Helper function to get the size_t compatible file size from a file
+ * descriptor.
+ *
+ * @return  The file size (in bytes).
+ * @param   fd              The file descriptor.
+ */
+static size_t GetFileSizeByFd(int fd)
+{
+    struct stat st;
+    if (fstat(fd, &st) == 0)
+    {
+        if (st.st_size <= 0)
+            return 0;
+        size_t cbFile = (size_t)st.st_size;
+        return (off_t)cbFile == st.st_size ? cbFile : ~(size_t)0;
+    }
+
+    CORELOGRELSYS((CORELOG_NAME "GetFileSizeByFd: fstat failed rc=%Rrc\n", RTErrConvertFromErrno(errno)));
+    return 0;
+}
+
+
+/**
+ * Helper function to get the size_t compatible size of a file given its path.
+ *
+ * @return  The file size (in bytes).
+ * @param   pszPath         Pointer to the full path of the file.
+ */
+static size_t GetFileSizeByName(const char *pszPath)
+{
+    int fd = open(pszPath, O_RDONLY);
+    if (fd < 0)
+    {
+        CORELOGRELSYS((CORELOG_NAME "GetFileSizeByName: failed to open %s rc=%Rrc\n", pszPath, RTErrConvertFromErrno(errno)));
+        return 0;
+    }
+
+    size_t cb = GetFileSizeByFd(fd);
+    close(fd);
+    return cb;
+}
+
+
+/**
+ * Pre-compute and pre-allocate sufficient memory for dumping core.
+ * This is meant to be called once, as a single-large anonymously
+ * mapped memory area which will be used during the core dumping routines.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int AllocMemoryArea(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore->pvCore == NULL, VERR_ALREADY_EXISTS);
+
+    static struct
+    {
+        const char *pszFilePath;        /* Proc based path */
+        size_t      cbHeader;           /* Size of header */
+        size_t      cbEntry;            /* Size of each entry in file */
+        size_t      cbAccounting;       /* Size of each accounting entry per entry */
+    } const s_aPreAllocTable[] =
+    {
+        { "/proc/%d/psinfo",     0,                  0,                     0 },
+        { "/proc/%d/map",        0,                  sizeof(prmap_t),       sizeof(RTSOLCOREMAPINFO) },
+        { "/proc/%d/auxv",       0,                  0,                     0 },
+        { "/proc/%d/lpsinfo",    sizeof(prheader_t), sizeof(lwpsinfo_t),    sizeof(RTSOLCORETHREADINFO) },
+        { "/proc/%d/lstatus",    0,                  0,                     0 },
+        { "/proc/%d/ldt",        0,                  0,                     0 },
+        { "/proc/%d/cred",       sizeof(prcred_t),   sizeof(gid_t),         0 },
+        { "/proc/%d/priv",       sizeof(prpriv_t),   sizeof(priv_chunk_t),  0 },
+    };
+
+    size_t cb = 0;
+    for (unsigned i = 0; i < RT_ELEMENTS(s_aPreAllocTable); i++)
+    {
+        char szPath[PATH_MAX];
+        RTStrPrintf(szPath, sizeof(szPath), s_aPreAllocTable[i].pszFilePath, (int)pSolCore->SolProc.Process);
+        size_t cbFile = GetFileSizeByName(szPath);
+        cb += cbFile;
+        if (   cbFile > 0
+            && s_aPreAllocTable[i].cbEntry > 0)
+        {
+            cb += ((cbFile - s_aPreAllocTable[i].cbHeader) / s_aPreAllocTable[i].cbEntry)
+                * (s_aPreAllocTable[i].cbAccounting > 0 ? s_aPreAllocTable[i].cbAccounting : 1);
+            cb += s_aPreAllocTable[i].cbHeader;
+        }
+    }
+
+    /*
+     * Make room for our own mapping accountant entry which will also be included in the core.
+     */
+    cb += sizeof(RTSOLCOREMAPINFO);
+
+    /*
+     * Allocate the required space, plus some extra room.
+     */
+    cb += _128K;
+    void *pv = mmap(NULL, cb, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1 /* fd */, 0 /* offset */);
+    if (pv != MAP_FAILED)
+    {
+        CORELOG((CORELOG_NAME "AllocMemoryArea: memory area of %u bytes allocated.\n", cb));
+        pSolCore->pvCore = pv;
+        pSolCore->pvFree = pv;
+        pSolCore->cbCore = cb;
+        return VINF_SUCCESS;
+    }
+    CORELOGRELSYS((CORELOG_NAME "AllocMemoryArea: failed cb=%u\n", cb));
+    return VERR_NO_MEMORY;
+}
+
+
+/**
+ * Free memory area used by the core object.
+ *
+ * @param pSolCore          Pointer to the core object.
+ */
+static void FreeMemoryArea(PRTSOLCORE pSolCore)
+{
+    AssertReturnVoid(pSolCore);
+    AssertReturnVoid(pSolCore->pvCore);
+    AssertReturnVoid(pSolCore->cbCore > 0);
+
+    munmap(pSolCore->pvCore, pSolCore->cbCore);
+    CORELOG((CORELOG_NAME "FreeMemoryArea: memory area of %u bytes freed.\n", pSolCore->cbCore));
+
+    pSolCore->pvCore = NULL;
+    pSolCore->pvFree= NULL;
+    pSolCore->cbCore = 0;
+}
+
+
+/**
+ * Get a chunk from the area of allocated memory.
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param cb                Size of requested chunk.
+ *
+ * @return Pointer to allocated memory, or NULL on failure.
+ */
+static void *GetMemoryChunk(PRTSOLCORE pSolCore, size_t cb)
+{
+    AssertReturn(pSolCore, NULL);
+    AssertReturn(pSolCore->pvCore, NULL);
+    AssertReturn(pSolCore->pvFree, NULL);
+
+    size_t cbAllocated = (char *)pSolCore->pvFree - (char *)pSolCore->pvCore;
+    if (cbAllocated < pSolCore->cbCore)
+    {
+        char *pb = (char *)pSolCore->pvFree;
+        pSolCore->pvFree = pb + cb;
+        return pb;
+    }
+
+    return NULL;
+}
+
+
+/**
+ * Reads the proc file's content into a newly allocated buffer.
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param pszProcFileName   Only the name of the file to read from
+ *                          (/proc/\<pid\> will be prepended)
+ * @param ppv               Where to store the allocated buffer.
+ * @param pcb               Where to store size of the buffer.
+ *
+ * @return IPRT status code. If the proc file is 0 bytes, VINF_SUCCESS is
+ *          returned with pointed to values of @c ppv, @c pcb set to NULL and 0
+ *          respectively.
+ */
+static int ProcReadFileInto(PRTSOLCORE pSolCore, const char *pszProcFileName, void **ppv, size_t *pcb)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    char szPath[PATH_MAX];
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/%s", (int)pSolCore->SolProc.Process, pszProcFileName);
+    int rc = VINF_SUCCESS;
+    int fd = open(szPath, O_RDONLY);
+    if (fd >= 0)
+    {
+        *pcb = GetFileSizeByFd(fd);
+        if (*pcb > 0)
+        {
+            *ppv = GetMemoryChunk(pSolCore, *pcb);
+            if (*ppv)
+                rc = ReadFileNoIntr(fd, *ppv, *pcb);
+            else
+                rc = VERR_NO_MEMORY;
+        }
+        else
+        {
+            *pcb =  0;
+            *ppv = NULL;
+            rc = VINF_SUCCESS;
+        }
+        close(fd);
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(fd);
+        CORELOGRELSYS((CORELOG_NAME "ProcReadFileInto: failed to open %s. rc=%Rrc\n", szPath, rc));
+    }
+    return rc;
+}
+
+
+/**
+ * Read process information (format psinfo_t) from /proc.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int ProcReadInfo(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    return ProcReadFileInto(pSolCore, "psinfo", &pSolProc->pvProcInfo, &pSolProc->cbProcInfo);
+}
+
+
+/**
+ * Read process status (format pstatus_t) from /proc.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int ProcReadStatus(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+
+    char szPath[PATH_MAX];
+    int rc = VINF_SUCCESS;
+
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/status", (int)pSolProc->Process);
+    int fd = open(szPath, O_RDONLY);
+    if (fd >= 0)
+    {
+        size_t cbProcStatus = sizeof(pstatus_t);
+        AssertCompile(sizeof(pstatus_t) == sizeof(pSolProc->ProcStatus));
+        rc = ReadFileNoIntr(fd, &pSolProc->ProcStatus, cbProcStatus);
+        close(fd);
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(fd);
+        CORELOGRELSYS((CORELOG_NAME "ProcReadStatus: failed to open %s. rc=%Rrc\n", szPath, rc));
+    }
+    return rc;
+}
+
+
+/**
+ * Read process credential information (format prcred_t + array of guid_t)
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadCred(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    return ProcReadFileInto(pSolCore, "cred", &pSolProc->pvCred, &pSolProc->cbCred);
+}
+
+
+/**
+ * Read process privilege information (format prpriv_t + array of priv_chunk_t)
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadPriv(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    int rc = ProcReadFileInto(pSolCore, "priv", (void **)&pSolProc->pPriv, &pSolProc->cbPriv);
+    if (RT_FAILURE(rc))
+        return rc;
+    pSolProc->pcPrivImpl = getprivimplinfo();
+    if (!pSolProc->pcPrivImpl)
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadPriv: getprivimplinfo returned NULL.\n"));
+        return VERR_INVALID_STATE;
+    }
+    return rc;
+}
+
+
+/**
+ * Read process LDT information (format array of struct ssd) from /proc.
+ *
+ * @return  IPRT status code.
+ * @param   pSolCore        Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadLdt(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    return ProcReadFileInto(pSolCore, "ldt", &pSolProc->pvLdt, &pSolProc->cbLdt);
+}
+
+
+/**
+ * Read process auxiliary vectors (format auxv_t) for the process.
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadAuxVecs(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    char szPath[PATH_MAX];
+    int rc = VINF_SUCCESS;
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/auxv", (int)pSolProc->Process);
+    int fd = open(szPath, O_RDONLY);
+    if (fd < 0)
+    {
+        rc = RTErrConvertFromErrno(fd);
+        CORELOGRELSYS((CORELOG_NAME "ProcReadAuxVecs: failed to open %s rc=%Rrc\n", szPath, rc));
+        return rc;
+    }
+
+    size_t cbAuxFile = GetFileSizeByFd(fd);
+    if (cbAuxFile >= sizeof(auxv_t))
+    {
+        pSolProc->pAuxVecs = (auxv_t*)GetMemoryChunk(pSolCore, cbAuxFile + sizeof(auxv_t));
+        if (pSolProc->pAuxVecs)
+        {
+            rc = ReadFileNoIntr(fd, pSolProc->pAuxVecs, cbAuxFile);
+            if (RT_SUCCESS(rc))
+            {
+                /* Terminate list of vectors */
+                pSolProc->cAuxVecs = cbAuxFile / sizeof(auxv_t);
+                CORELOG((CORELOG_NAME "ProcReadAuxVecs: cbAuxFile=%u auxv_t size %d cAuxVecs=%u\n", cbAuxFile, sizeof(auxv_t),
+                         pSolProc->cAuxVecs));
+                if (pSolProc->cAuxVecs > 0)
+                {
+                    pSolProc->pAuxVecs[pSolProc->cAuxVecs].a_type = AT_NULL;
+                    pSolProc->pAuxVecs[pSolProc->cAuxVecs].a_un.a_val = 0L;
+                    close(fd);
+                    return VINF_SUCCESS;
+                }
+
+                CORELOGRELSYS((CORELOG_NAME "ProcReadAuxVecs: Invalid vector count %u\n", pSolProc->cAuxVecs));
+                rc = VERR_READ_ERROR;
+            }
+            else
+                CORELOGRELSYS((CORELOG_NAME "ProcReadAuxVecs: ReadFileNoIntr failed. rc=%Rrc cbAuxFile=%u\n", rc, cbAuxFile));
+
+            pSolProc->pAuxVecs = NULL;
+            pSolProc->cAuxVecs = 0;
+        }
+        else
+        {
+            CORELOGRELSYS((CORELOG_NAME "ProcReadAuxVecs: no memory for %u bytes\n", cbAuxFile + sizeof(auxv_t)));
+            rc = VERR_NO_MEMORY;
+        }
+    }
+    else
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadAuxVecs: aux file too small %u, expecting %u or more\n", cbAuxFile, sizeof(auxv_t)));
+        rc = VERR_READ_ERROR;
+    }
+
+    close(fd);
+    return rc;
+}
+
+
+/*
+ * Find an element in the process' auxiliary vector.
+ */
+static long GetAuxVal(PRTSOLCOREPROCESS pSolProc, int Type)
+{
+    AssertReturn(pSolProc, -1);
+    if (pSolProc->pAuxVecs)
+    {
+        auxv_t *pAuxVec = pSolProc->pAuxVecs;
+        for (; pAuxVec->a_type != AT_NULL; pAuxVec++)
+        {
+            if (pAuxVec->a_type == Type)
+                return pAuxVec->a_un.a_val;
+        }
+    }
+    return -1;
+}
+
+
+/**
+ * Read the process mappings (format prmap_t array).
+ *
+ * @return IPRT status code.
+ * @param   pSolCore            Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadMappings(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    char szPath[PATH_MAX];
+    int rc = VINF_SUCCESS;
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/map", (int)pSolProc->Process);
+    int fdMap = open(szPath, O_RDONLY);
+    if (fdMap < 0)
+    {
+        rc = RTErrConvertFromErrno(errno);
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: failed to open %s. rc=%Rrc\n", szPath, rc));
+        return rc;
+    }
+
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/as", (int)pSolProc->Process);
+    pSolProc->fdAs = open(szPath, O_RDONLY);
+    if (pSolProc->fdAs >= 0)
+    {
+        /*
+         * Allocate and read all the prmap_t objects from proc.
+         */
+        size_t cbMapFile = GetFileSizeByFd(fdMap);
+        if (cbMapFile >= sizeof(prmap_t))
+        {
+            prmap_t *pMap = (prmap_t*)GetMemoryChunk(pSolCore, cbMapFile);
+            if (pMap)
+            {
+                rc = ReadFileNoIntr(fdMap, pMap, cbMapFile);
+                if (RT_SUCCESS(rc))
+                {
+                    pSolProc->cMappings = cbMapFile / sizeof(prmap_t);
+                    if (pSolProc->cMappings > 0)
+                    {
+                        /*
+                         * Allocate for each prmap_t object, a corresponding RTSOLCOREMAPINFO object.
+                         */
+                        pSolProc->pMapInfoHead = (PRTSOLCOREMAPINFO)GetMemoryChunk(pSolCore,
+                                                                                pSolProc->cMappings * sizeof(RTSOLCOREMAPINFO));
+                        if (pSolProc->pMapInfoHead)
+                        {
+                            /*
+                             * Associate the prmap_t with the mapping info object.
+                             */
+                            /*Assert(pSolProc->pMapInfoHead == NULL); - does not make sense */
+                            PRTSOLCOREMAPINFO pCur = pSolProc->pMapInfoHead;
+                            PRTSOLCOREMAPINFO pPrev = NULL;
+                            for (uint64_t i = 0; i < pSolProc->cMappings; i++, pMap++, pCur++)
+                            {
+                                memcpy(&pCur->pMap, pMap, sizeof(pCur->pMap));
+                                if (pPrev)
+                                    pPrev->pNext = pCur;
+
+                                pCur->fError = 0;
+
+                                /*
+                                 * Make sure we can read the mapping, otherwise mark them to be skipped.
+                                 */
+                                char achBuf[PAGE_SIZE];
+                                uint64_t k = 0;
+                                while (k < pCur->pMap.pr_size)
+                                {
+                                    size_t cb = RT_MIN(sizeof(achBuf), pCur->pMap.pr_size - k);
+                                    int rc2 = ProcReadAddrSpace(pSolProc, pCur->pMap.pr_vaddr + k, &achBuf, cb);
+                                    if (RT_FAILURE(rc2))
+                                    {
+                                        CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: skipping mapping. vaddr=%#x rc=%Rrc\n",
+                                                       pCur->pMap.pr_vaddr, rc2));
+
+                                        /*
+                                         * Instead of storing the actual mapping data which we failed to read, the core
+                                         * will contain an errno in place. So we adjust the prmap_t's size field too
+                                         * so the program header offsets match.
+                                         */
+                                        pCur->pMap.pr_size = RT_ALIGN_Z(sizeof(int), 8);
+                                        pCur->fError = errno;
+                                        if (pCur->fError == 0)  /* huh!? somehow errno got reset? fake one! EFAULT is nice. */
+                                            pCur->fError = EFAULT;
+                                        break;
+                                    }
+                                    k += cb;
+                                }
+
+                                pPrev = pCur;
+                            }
+                            if (pPrev)
+                                pPrev->pNext = NULL;
+
+                            close(fdMap);
+                            close(pSolProc->fdAs);
+                            pSolProc->fdAs = -1;
+                            CORELOG((CORELOG_NAME "ProcReadMappings: successfully read in %u mappings\n", pSolProc->cMappings));
+                            return VINF_SUCCESS;
+                        }
+
+                        CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: GetMemoryChunk failed %u\n",
+                                       pSolProc->cMappings * sizeof(RTSOLCOREMAPINFO)));
+                        rc = VERR_NO_MEMORY;
+                    }
+                    else
+                    {
+                        CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: Invalid mapping count %u\n", pSolProc->cMappings));
+                        rc = VERR_READ_ERROR;
+                    }
+                }
+                else
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: FileReadNoIntr failed. rc=%Rrc cbMapFile=%u\n", rc,
+                                   cbMapFile));
+                }
+            }
+            else
+            {
+                CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: GetMemoryChunk failed. cbMapFile=%u\n", cbMapFile));
+                rc = VERR_NO_MEMORY;
+            }
+        }
+
+        close(pSolProc->fdAs);
+        pSolProc->fdAs = -1;
+    }
+    else
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMappings: failed to open %s. rc=%Rrc\n", szPath, rc));
+
+    close(fdMap);
+    return rc;
+}
+
+
+/**
+ * Reads the thread information for all threads in the process.
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @remarks Should not be called before successful call to @see AllocMemoryArea()
+ */
+static int ProcReadThreads(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    AssertReturn(pSolProc->pCurThreadCtx, VERR_NO_DATA);
+
+    /*
+     * Read the information for threads.
+     * Format: prheader_t + array of lwpsinfo_t's.
+     */
+    size_t cbInfoHdrAndData;
+    void *pvInfoHdr = NULL;
+    int rc = ProcReadFileInto(pSolCore, "lpsinfo", &pvInfoHdr, &cbInfoHdrAndData);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Read the status of threads.
+         * Format: prheader_t + array of lwpstatus_t's.
+         */
+        void *pvStatusHdr = NULL;
+        size_t cbStatusHdrAndData;
+        rc = ProcReadFileInto(pSolCore, "lstatus", &pvStatusHdr, &cbStatusHdrAndData);
+        if (RT_SUCCESS(rc))
+        {
+            prheader_t *pInfoHdr   = (prheader_t *)pvInfoHdr;
+            prheader_t *pStatusHdr = (prheader_t *)pvStatusHdr;
+            lwpstatus_t *pStatus   = (lwpstatus_t *)((uintptr_t)pStatusHdr + sizeof(prheader_t));
+            lwpsinfo_t *pInfo      = (lwpsinfo_t *)((uintptr_t)pInfoHdr + sizeof(prheader_t));
+            uint64_t cStatus       = pStatusHdr->pr_nent;
+            uint64_t cInfo         = pInfoHdr->pr_nent;
+
+            CORELOG((CORELOG_NAME "ProcReadThreads: read info(%u) status(%u), threads:cInfo=%u cStatus=%u\n", cbInfoHdrAndData,
+                        cbStatusHdrAndData, cInfo, cStatus));
+
+            /*
+             * Minor sanity size check (remember sizeof lwpstatus_t & lwpsinfo_t is <= size in file per entry).
+             */
+            if (   (cbStatusHdrAndData - sizeof(prheader_t)) % pStatusHdr->pr_entsize == 0
+                && (cbInfoHdrAndData - sizeof(prheader_t)) % pInfoHdr->pr_entsize == 0)
+            {
+                /*
+                 * Make sure we have a matching lstatus entry for an lpsinfo entry unless
+                 * it is a zombie thread, in which case we will not have a matching lstatus entry.
+                 */
+                for (; cInfo != 0; cInfo--)
+                {
+                    if (pInfo->pr_sname != 'Z') /* zombie */
+                    {
+                        if (   cStatus == 0
+                            || pStatus->pr_lwpid != pInfo->pr_lwpid)
+                        {
+                            CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: cStatus = %u pStatuslwpid=%d infolwpid=%d\n", cStatus,
+                                        pStatus->pr_lwpid, pInfo->pr_lwpid));
+                            rc = VERR_INVALID_STATE;
+                            break;
+                        }
+                        pStatus = (lwpstatus_t *)((uintptr_t)pStatus + pStatusHdr->pr_entsize);
+                        cStatus--;
+                    }
+                    pInfo = (lwpsinfo_t *)((uintptr_t)pInfo + pInfoHdr->pr_entsize);
+                }
+
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * There can still be more lwpsinfo_t's than lwpstatus_t's, build the
+                     * lists accordingly.
+                     */
+                    pStatus = (lwpstatus_t *)((uintptr_t)pStatusHdr + sizeof(prheader_t));
+                    pInfo = (lwpsinfo_t *)((uintptr_t)pInfoHdr + sizeof(prheader_t));
+                    cInfo = pInfoHdr->pr_nent;
+                    cStatus = pInfoHdr->pr_nent;
+
+                    size_t cbThreadInfo = RT_MAX(cStatus, cInfo) * sizeof(RTSOLCORETHREADINFO);
+                    pSolProc->pThreadInfoHead = (PRTSOLCORETHREADINFO)GetMemoryChunk(pSolCore, cbThreadInfo);
+                    if (pSolProc->pThreadInfoHead)
+                    {
+                        PRTSOLCORETHREADINFO pCur = pSolProc->pThreadInfoHead;
+                        PRTSOLCORETHREADINFO pPrev = NULL;
+                        for (uint64_t i = 0; i < cInfo; i++, pCur++)
+                        {
+                            pCur->Info = *pInfo;
+                            if (   pInfo->pr_sname != 'Z'
+                                && pInfo->pr_lwpid == pStatus->pr_lwpid)
+                            {
+                                /*
+                                 * Adjust the context of the dumping thread to reflect the context
+                                 * when the core dump got initiated before whatever signal caused it.
+                                 */
+                                if (   pStatus          /* noid droid */
+                                    && pStatus->pr_lwpid == (id_t)pSolProc->hCurThread)
+                                {
+                                    AssertCompile(sizeof(pStatus->pr_reg) == sizeof(pSolProc->pCurThreadCtx->uc_mcontext.gregs));
+                                    AssertCompile(sizeof(pStatus->pr_fpreg) == sizeof(pSolProc->pCurThreadCtx->uc_mcontext.fpregs));
+                                    memcpy(&pStatus->pr_reg, &pSolProc->pCurThreadCtx->uc_mcontext.gregs, sizeof(pStatus->pr_reg));
+                                    memcpy(&pStatus->pr_fpreg, &pSolProc->pCurThreadCtx->uc_mcontext.fpregs, sizeof(pStatus->pr_fpreg));
+
+                                    AssertCompile(sizeof(pStatus->pr_lwphold) == sizeof(pSolProc->pCurThreadCtx->uc_sigmask));
+                                    memcpy(&pStatus->pr_lwphold, &pSolProc->pCurThreadCtx->uc_sigmask, sizeof(pStatus->pr_lwphold));
+                                    pStatus->pr_ustack = (uintptr_t)&pSolProc->pCurThreadCtx->uc_stack;
+
+                                    CORELOG((CORELOG_NAME "ProcReadThreads: patched dumper thread with pre-dump time context.\n"));
+                                }
+
+                                pCur->pStatus = pStatus;
+                                pStatus = (lwpstatus_t *)((uintptr_t)pStatus + pStatusHdr->pr_entsize);
+                            }
+                            else
+                            {
+                                CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: missing status for lwp %d\n", pInfo->pr_lwpid));
+                                pCur->pStatus = NULL;
+                            }
+
+                            if (pPrev)
+                                pPrev->pNext = pCur;
+                            pPrev = pCur;
+                            pInfo = (lwpsinfo_t *)((uintptr_t)pInfo + pInfoHdr->pr_entsize);
+                        }
+                        if (pPrev)
+                            pPrev->pNext = NULL;
+
+                        CORELOG((CORELOG_NAME "ProcReadThreads: successfully read %u threads.\n", cInfo));
+                        pSolProc->cThreads = cInfo;
+                        return VINF_SUCCESS;
+                    }
+                    else
+                    {
+                        CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: GetMemoryChunk failed for %u bytes\n", cbThreadInfo));
+                        rc = VERR_NO_MEMORY;
+                    }
+                }
+                else
+                    CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: Invalid state information for threads. rc=%Rrc\n", rc));
+            }
+            else
+            {
+                CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: huh!? cbStatusHdrAndData=%u prheader_t=%u entsize=%u\n",
+                               cbStatusHdrAndData, sizeof(prheader_t), pStatusHdr->pr_entsize));
+                CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: huh!? cbInfoHdrAndData=%u entsize=%u\n", cbInfoHdrAndData,
+                               pStatusHdr->pr_entsize));
+                rc = VERR_INVALID_STATE;
+            }
+        }
+        else
+            CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: ReadFileNoIntr failed for \"lpsinfo\" rc=%Rrc\n", rc));
+    }
+    else
+        CORELOGRELSYS((CORELOG_NAME "ProcReadThreads: ReadFileNoIntr failed for \"lstatus\" rc=%Rrc\n", rc));
+    return rc;
+}
+
+
+/**
+ * Reads miscellaneous information that is collected as part of a core file.
+ * This may include platform name, zone name and other OS-specific information.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int ProcReadMiscInfo(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+
+#ifdef RT_OS_SOLARIS
+    /*
+     * Read the platform name, uname string and zone name.
+     */
+    int rc = sysinfo(SI_PLATFORM, pSolProc->szPlatform, sizeof(pSolProc->szPlatform));
+    if (rc == -1)
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMiscInfo: sysinfo failed. rc=%d errno=%d\n", rc, errno));
+        return VERR_GENERAL_FAILURE;
+    }
+    pSolProc->szPlatform[sizeof(pSolProc->szPlatform) - 1] = '\0';
+
+    rc = uname(&pSolProc->UtsName);
+    if (rc == -1)
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMiscInfo: uname failed. rc=%d errno=%d\n", rc, errno));
+        return VERR_GENERAL_FAILURE;
+    }
+
+    /*
+     * See comment in GetOldProcessInfo() for why we need to verify the offset here.
+     * It's not perfect, but it should be fine unless they really mess up the structure
+     * layout in the future. See @bugref{8479}.
+     */
+    size_t const offZoneId = RT_UOFFSETOF(psinfo_t, pr_zoneid);
+    if (pSolProc->cbProcInfo < offZoneId)
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMiscInfo: psinfo size mismatch. cbProcInfo=%u expected >= %u\n",
+                       pSolProc->cbProcInfo, offZoneId));
+        return VERR_GENERAL_FAILURE;
+    }
+
+    psinfo_t *pProcInfo = (psinfo_t *)pSolProc->pvProcInfo;
+    rc = getzonenamebyid(pProcInfo->pr_zoneid, pSolProc->szZoneName, sizeof(pSolProc->szZoneName));
+    if (rc < 0)
+    {
+        CORELOGRELSYS((CORELOG_NAME "ProcReadMiscInfo: getzonenamebyid failed. rc=%d errno=%d zoneid=%d\n", rc, errno,
+                       pProcInfo->pr_zoneid));
+        return VERR_GENERAL_FAILURE;
+    }
+    pSolProc->szZoneName[sizeof(pSolProc->szZoneName) - 1] = '\0';
+    rc = VINF_SUCCESS;
+
+#else
+# error Port Me!
+#endif
+    return rc;
+}
+
+
+/**
+ * On Solaris use the old-style procfs interfaces but the core file still should have this
+ * info. for backward and GDB compatibility, hence the need for this ugly function.
+ *
+ * @returns IPRT status code.
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param pInfo             Pointer to the old prpsinfo_t structure to update.
+ */
+static int GetOldProcessInfo(PRTSOLCORE pSolCore, prpsinfo_t *pInfo)
+{
+    AssertReturn(pSolCore, VERR_INVALID_PARAMETER);
+    AssertReturn(pInfo,    VERR_INVALID_PARAMETER);
+
+    /*
+     * The psinfo_t and the size of /proc/<pid>/psinfo varies both within the same Solaris system
+     * and across Solaris major versions. However, manual dumping of the structure and offsets shows
+     * that they changed the size of lwpsinfo_t and the size of the lwpsinfo_t::pr_filler.
+     *
+     * The proc psinfo file will be what gets dumped ultimately in the core file but we still need
+     * to read the fields to translate to the older process info structure here.
+     *
+     * See @bugref{8479}.
+     */
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+
+    size_t offLwp         = RT_UOFFSETOF(psinfo_t, pr_lwp);
+    /* last member we care about in lwpsinfo_t is pr_bindpset which is also present on ancient Solaris version we use for
+       building the additions. Should be safe enough as we don't need/access members upto or beyond that point anyway. */
+    size_t offLastOnProc  = RT_UOFFSETOF(lwpsinfo_t, pr_bindpset);
+    if (pSolProc->cbProcInfo >= offLwp + offLastOnProc)
+    {
+        psinfo_t *pSrc = (psinfo_t *)pSolProc->pvProcInfo;
+        memset(pInfo, 0, sizeof(prpsinfo_t));
+        pInfo->pr_state    = pSrc->pr_lwp.pr_state;
+        pInfo->pr_zomb     = (pInfo->pr_state == SZOMB);
+        RTStrCopy(pInfo->pr_clname, sizeof(pInfo->pr_clname), pSrc->pr_lwp.pr_clname);
+        RTStrCopy(pInfo->pr_fname, sizeof(pInfo->pr_fname), pSrc->pr_fname);
+        memcpy(&pInfo->pr_psargs, &pSrc->pr_psargs, sizeof(pInfo->pr_psargs));
+        pInfo->pr_nice     = pSrc->pr_lwp.pr_nice;
+        pInfo->pr_flag     = pSrc->pr_lwp.pr_flag;
+        pInfo->pr_uid      = pSrc->pr_uid;
+        pInfo->pr_gid      = pSrc->pr_gid;
+        pInfo->pr_pid      = pSrc->pr_pid;
+        pInfo->pr_ppid     = pSrc->pr_ppid;
+        pInfo->pr_pgrp     = pSrc->pr_pgid;
+        pInfo->pr_sid      = pSrc->pr_sid;
+        pInfo->pr_addr     = (caddr_t)pSrc->pr_addr;
+        pInfo->pr_size     = pSrc->pr_size;
+        pInfo->pr_rssize   = pSrc->pr_rssize;
+        pInfo->pr_wchan    = (caddr_t)pSrc->pr_lwp.pr_wchan;
+        pInfo->pr_start    = pSrc->pr_start;
+        pInfo->pr_time     = pSrc->pr_time;
+        pInfo->pr_pri      = pSrc->pr_lwp.pr_pri;
+        pInfo->pr_oldpri   = pSrc->pr_lwp.pr_oldpri;
+        pInfo->pr_cpu      = pSrc->pr_lwp.pr_cpu;
+        pInfo->pr_ottydev  = cmpdev(pSrc->pr_ttydev);
+        pInfo->pr_lttydev  = pSrc->pr_ttydev;
+        pInfo->pr_syscall  = pSrc->pr_lwp.pr_syscall;
+        pInfo->pr_ctime    = pSrc->pr_ctime;
+        pInfo->pr_bysize   = pSrc->pr_size * PAGESIZE;
+        pInfo->pr_byrssize = pSrc->pr_rssize * PAGESIZE;
+        pInfo->pr_argc     = pSrc->pr_argc;
+        pInfo->pr_argv     = (char **)pSrc->pr_argv;
+        pInfo->pr_envp     = (char **)pSrc->pr_envp;
+        pInfo->pr_wstat    = pSrc->pr_wstat;
+        pInfo->pr_pctcpu   = pSrc->pr_pctcpu;
+        pInfo->pr_pctmem   = pSrc->pr_pctmem;
+        pInfo->pr_euid     = pSrc->pr_euid;
+        pInfo->pr_egid     = pSrc->pr_egid;
+        pInfo->pr_aslwpid  = 0;
+        pInfo->pr_dmodel   = pSrc->pr_dmodel;
+
+        return VINF_SUCCESS;
+    }
+
+    CORELOGRELSYS((CORELOG_NAME "GetOldProcessInfo: Size/offset mismatch. offLwp=%u offLastOnProc=%u cbProcInfo=%u\n",
+                   offLwp, offLastOnProc, pSolProc->cbProcInfo));
+    return VERR_MISMATCH;
+}
+
+
+/**
+ * On Solaris use the old-style procfs interfaces but the core file still should have this
+ * info. for backward and GDB compatibility, hence the need for this ugly function.
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param pInfo             Pointer to the thread info.
+ * @param pStatus           Pointer to the thread status.
+ * @param pDst              Pointer to the old-style status structure to update.
+ *
+ */
+static void GetOldProcessStatus(PRTSOLCORE pSolCore, lwpsinfo_t *pInfo, lwpstatus_t *pStatus, prstatus_t *pDst)
+{
+    AssertReturnVoid(pSolCore);
+    AssertReturnVoid(pInfo);
+    AssertReturnVoid(pStatus);
+    AssertReturnVoid(pDst);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    memset(pDst, 0, sizeof(prstatus_t));
+    if (pStatus->pr_flags & PR_STOPPED)
+        pDst->pr_flags = 0x0001;
+    if (pStatus->pr_flags & PR_ISTOP)
+        pDst->pr_flags = 0x0002;
+    if (pStatus->pr_flags & PR_DSTOP)
+        pDst->pr_flags = 0x0004;
+    if (pStatus->pr_flags & PR_ASLEEP)
+        pDst->pr_flags = 0x0008;
+    if (pStatus->pr_flags & PR_FORK)
+        pDst->pr_flags = 0x0010;
+    if (pStatus->pr_flags & PR_RLC)
+        pDst->pr_flags = 0x0020;
+    /* PR_PTRACE is never set */
+    if (pStatus->pr_flags & PR_PCINVAL)
+        pDst->pr_flags = 0x0080;
+    if (pStatus->pr_flags & PR_ISSYS)
+        pDst->pr_flags = 0x0100;
+    if (pStatus->pr_flags & PR_STEP)
+        pDst->pr_flags = 0x0200;
+    if (pStatus->pr_flags & PR_KLC)
+        pDst->pr_flags = 0x0400;
+    if (pStatus->pr_flags & PR_ASYNC)
+        pDst->pr_flags = 0x0800;
+    if (pStatus->pr_flags & PR_PTRACE)
+        pDst->pr_flags = 0x1000;
+    if (pStatus->pr_flags & PR_MSACCT)
+        pDst->pr_flags = 0x2000;
+    if (pStatus->pr_flags & PR_BPTADJ)
+        pDst->pr_flags = 0x4000;
+    if (pStatus->pr_flags & PR_ASLWP)
+        pDst->pr_flags = 0x8000;
+
+    pDst->pr_who        = pStatus->pr_lwpid;
+    pDst->pr_why        = pStatus->pr_why;
+    pDst->pr_what       = pStatus->pr_what;
+    pDst->pr_info       = pStatus->pr_info;
+    pDst->pr_cursig     = pStatus->pr_cursig;
+    pDst->pr_sighold    = pStatus->pr_lwphold;
+    pDst->pr_altstack   = pStatus->pr_altstack;
+    pDst->pr_action     = pStatus->pr_action;
+    pDst->pr_syscall    = pStatus->pr_syscall;
+    pDst->pr_nsysarg    = pStatus->pr_nsysarg;
+    pDst->pr_lwppend    = pStatus->pr_lwppend;
+    pDst->pr_oldcontext = (ucontext_t *)pStatus->pr_oldcontext;
+    memcpy(pDst->pr_reg, pStatus->pr_reg, sizeof(pDst->pr_reg));
+    memcpy(pDst->pr_sysarg, pStatus->pr_sysarg, sizeof(pDst->pr_sysarg));
+    RTStrCopy(pDst->pr_clname, sizeof(pDst->pr_clname), pStatus->pr_clname);
+
+    pDst->pr_nlwp       = pSolProc->ProcStatus.pr_nlwp;
+    pDst->pr_sigpend    = pSolProc->ProcStatus.pr_sigpend;
+    pDst->pr_pid        = pSolProc->ProcStatus.pr_pid;
+    pDst->pr_ppid       = pSolProc->ProcStatus.pr_ppid;
+    pDst->pr_pgrp       = pSolProc->ProcStatus.pr_pgid;
+    pDst->pr_sid        = pSolProc->ProcStatus.pr_sid;
+    pDst->pr_utime      = pSolProc->ProcStatus.pr_utime;
+    pDst->pr_stime      = pSolProc->ProcStatus.pr_stime;
+    pDst->pr_cutime     = pSolProc->ProcStatus.pr_cutime;
+    pDst->pr_cstime     = pSolProc->ProcStatus.pr_cstime;
+    pDst->pr_brkbase    = (caddr_t)pSolProc->ProcStatus.pr_brkbase;
+    pDst->pr_brksize    = pSolProc->ProcStatus.pr_brksize;
+    pDst->pr_stkbase    = (caddr_t)pSolProc->ProcStatus.pr_stkbase;
+    pDst->pr_stksize    = pSolProc->ProcStatus.pr_stksize;
+
+    pDst->pr_processor  = (short)pInfo->pr_onpro;
+    pDst->pr_bind       = (short)pInfo->pr_bindpro;
+    pDst->pr_instr      = pStatus->pr_instr;
+}
+
+
+/**
+ * Callback for rtCoreDumperForEachThread to suspend a thread.
+ *
+ * @param pSolCore              Pointer to the core object.
+ * @param pvThreadInfo          Opaque pointer to thread information.
+ *
+ * @return IPRT status code.
+ */
+static int suspendThread(PRTSOLCORE pSolCore, void *pvThreadInfo)
+{
+    AssertPtrReturn(pvThreadInfo, VERR_INVALID_POINTER);
+    NOREF(pSolCore);
+
+    lwpsinfo_t *pThreadInfo = (lwpsinfo_t *)pvThreadInfo;
+    CORELOG((CORELOG_NAME ":suspendThread %d\n", (lwpid_t)pThreadInfo->pr_lwpid));
+    if ((lwpid_t)pThreadInfo->pr_lwpid != pSolCore->SolProc.hCurThread)
+        _lwp_suspend(pThreadInfo->pr_lwpid);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Callback for rtCoreDumperForEachThread to resume a thread.
+ *
+ * @param pSolCore              Pointer to the core object.
+ * @param pvThreadInfo          Opaque pointer to thread information.
+ *
+ * @return IPRT status code.
+ */
+static int resumeThread(PRTSOLCORE pSolCore, void *pvThreadInfo)
+{
+    AssertPtrReturn(pvThreadInfo, VERR_INVALID_POINTER);
+    NOREF(pSolCore);
+
+    lwpsinfo_t *pThreadInfo = (lwpsinfo_t *)pvThreadInfo;
+    CORELOG((CORELOG_NAME ":resumeThread %d\n", (lwpid_t)pThreadInfo->pr_lwpid));
+    if ((lwpid_t)pThreadInfo->pr_lwpid != (lwpid_t)pSolCore->SolProc.hCurThread)
+        _lwp_continue(pThreadInfo->pr_lwpid);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Calls a thread worker function for all threads in the process as described by /proc
+ *
+ * @param pSolCore              Pointer to the core object.
+ * @param pcThreads             Number of threads read.
+ * @param pfnWorker             Callback function for each thread.
+ *
+ * @return IPRT status code.
+ */
+static int rtCoreDumperForEachThread(PRTSOLCORE pSolCore,  uint64_t *pcThreads, PFNRTSOLCORETHREADWORKER pfnWorker)
+{
+    AssertPtrReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+
+    /*
+     * Read the information for threads.
+     * Format: prheader_t + array of lwpsinfo_t's.
+     */
+    char szLpsInfoPath[PATH_MAX];
+    RTStrPrintf(szLpsInfoPath, sizeof(szLpsInfoPath), "/proc/%d/lpsinfo", (int)pSolProc->Process);
+
+    int rc = VINF_SUCCESS;
+    int fd = open(szLpsInfoPath, O_RDONLY);
+    if (fd >= 0)
+    {
+        size_t cbInfoHdrAndData = GetFileSizeByFd(fd);
+        void *pvInfoHdr = mmap(NULL, cbInfoHdrAndData, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+                               -1 /* fd */, 0 /* offset */);
+        if (pvInfoHdr != MAP_FAILED)
+        {
+            rc = ReadFileNoIntr(fd, pvInfoHdr, cbInfoHdrAndData);
+            if (RT_SUCCESS(rc))
+            {
+                prheader_t *pHeader = (prheader_t *)pvInfoHdr;
+                lwpsinfo_t *pThreadInfo = (lwpsinfo_t *)((uintptr_t)pvInfoHdr + sizeof(prheader_t));
+                for (long i = 0; i < pHeader->pr_nent; i++)
+                {
+                    pfnWorker(pSolCore, pThreadInfo);
+                    pThreadInfo = (lwpsinfo_t *)((uintptr_t)pThreadInfo + pHeader->pr_entsize);
+                }
+                if (pcThreads)
+                    *pcThreads = pHeader->pr_nent;
+            }
+
+            munmap(pvInfoHdr, cbInfoHdrAndData);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+        close(fd);
+    }
+    else
+        rc = RTErrConvertFromErrno(rc);
+
+    return rc;
+}
+
+
+/**
+ * Resume all threads of this process.
+ *
+ * @param pSolCore              Pointer to the core object.
+ *
+ * @return IPRT status code..
+ */
+static int rtCoreDumperResumeThreads(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    uint64_t cThreads;
+    return rtCoreDumperForEachThread(pSolCore, &cThreads, resumeThread);
+}
+
+
+/**
+ * Stop all running threads of this process except the current one.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int rtCoreDumperSuspendThreads(PRTSOLCORE pSolCore)
+{
+    AssertPtrReturn(pSolCore, VERR_INVALID_POINTER);
+
+    /*
+     * This function tries to ensures while we suspend threads, no newly spawned threads
+     * or a combination of spawning and terminating threads can cause any threads to be left running.
+     * The assumption here is that threads can only increase not decrease across iterations.
+     */
+    uint16_t cTries = 0;
+    uint64_t aThreads[4];
+    RT_ZERO(aThreads);
+    int rc = VERR_GENERAL_FAILURE;
+    void *pv = NULL;
+    size_t cb = 0;
+    for (cTries = 0; cTries < RT_ELEMENTS(aThreads); cTries++)
+    {
+        rc = rtCoreDumperForEachThread(pSolCore, &aThreads[cTries], suspendThread);
+        if (RT_FAILURE(rc))
+            break;
+    }
+    if (   RT_SUCCESS(rc)
+        && aThreads[cTries - 1] != aThreads[cTries - 2])
+    {
+        CORELOGRELSYS((CORELOG_NAME "rtCoreDumperSuspendThreads: possible thread bomb!?\n"));
+        rc = VERR_TIMEOUT;
+    }
+    return rc;
+}
+
+
+/**
+ * Returns size of an ELF NOTE header given the size of data the NOTE section will contain.
+ *
+ * @param cb                Size of the data.
+ *
+ * @return Size of data actually used for NOTE header and section.
+ */
+static inline size_t ElfNoteHeaderSize(size_t cb)
+{
+    return sizeof(ELFNOTEHDR) + RT_ALIGN_Z(cb, 4);
+}
+
+
+/**
+ * Write an ELF NOTE header into the core file.
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param Type              Type of this NOTE section.
+ * @param pcv               Opaque pointer to the data, if NULL only computes size.
+ * @param cb                Size of the data.
+ *
+ * @return IPRT status code.
+ */
+static int ElfWriteNoteHeader(PRTSOLCORE pSolCore, uint_t Type, const void *pcv, size_t cb)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+    AssertReturn(pcv, VERR_INVALID_POINTER);
+    AssertReturn(cb > 0, VERR_NO_DATA);
+    AssertReturn(pSolCore->pfnWriter, VERR_WRITE_ERROR);
+    AssertReturn(pSolCore->fdCoreFile >= 0, VERR_INVALID_HANDLE);
+
+    int rc = VERR_GENERAL_FAILURE;
+#ifdef RT_OS_SOLARIS
+    ELFNOTEHDR ElfNoteHdr;
+    RT_ZERO(ElfNoteHdr);
+    ElfNoteHdr.achName[0] = 'C';
+    ElfNoteHdr.achName[1] = 'O';
+    ElfNoteHdr.achName[2] = 'R';
+    ElfNoteHdr.achName[3] = 'E';
+
+    /*
+     * This is a known violation of the 64-bit ELF spec., see xTracker @bugref{5211}
+     * for the historic reasons as to the padding and 'namesz' anomalies.
+     */
+    static const char s_achPad[3] = { 0, 0, 0 };
+    size_t cbAlign = RT_ALIGN_Z(cb, 4);
+    ElfNoteHdr.Hdr.n_namesz = 5;
+    ElfNoteHdr.Hdr.n_type = Type;
+    ElfNoteHdr.Hdr.n_descsz = cbAlign;
+
+    /*
+     * Write note header and description.
+     */
+    rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &ElfNoteHdr, sizeof(ElfNoteHdr));
+    if (RT_SUCCESS(rc))
+    {
+       rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, pcv, cb);
+       if (RT_SUCCESS(rc))
+       {
+           if (cbAlign > cb)
+               rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, s_achPad, cbAlign - cb);
+       }
+    }
+
+    if (RT_FAILURE(rc))
+        CORELOGRELSYS((CORELOG_NAME "ElfWriteNote: pfnWriter failed. Type=%d rc=%Rrc\n", Type, rc));
+#else
+#error Port Me!
+#endif
+    return rc;
+}
+
+
+/**
+ * Computes the size of NOTE section for the given core type.
+ * Solaris has two types of program header information (new and old).
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param enmType           Type of core file information required.
+ *
+ * @return Size of NOTE section.
+ */
+static size_t ElfNoteSectionSize(PRTSOLCORE pSolCore, RTSOLCORETYPE enmType)
+{
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    size_t cb = 0;
+    switch (enmType)
+    {
+        case enmOldEra:
+        {
+            cb += ElfNoteHeaderSize(sizeof(prpsinfo_t));
+            cb += ElfNoteHeaderSize(pSolProc->cAuxVecs * sizeof(auxv_t));
+            cb += ElfNoteHeaderSize(strlen(pSolProc->szPlatform));
+
+            PRTSOLCORETHREADINFO pThreadInfo = pSolProc->pThreadInfoHead;
+            while (pThreadInfo)
+            {
+                if (pThreadInfo->pStatus)
+                {
+                    cb += ElfNoteHeaderSize(sizeof(prstatus_t));
+                    cb += ElfNoteHeaderSize(sizeof(prfpregset_t));
+                }
+                pThreadInfo = pThreadInfo->pNext;
+            }
+
+            break;
+        }
+
+        case enmNewEra:
+        {
+            cb += ElfNoteHeaderSize(sizeof(psinfo_t));
+            cb += ElfNoteHeaderSize(sizeof(pstatus_t));
+            cb += ElfNoteHeaderSize(pSolProc->cAuxVecs * sizeof(auxv_t));
+            cb += ElfNoteHeaderSize(strlen(pSolProc->szPlatform) + 1);
+            cb += ElfNoteHeaderSize(sizeof(struct utsname));
+            cb += ElfNoteHeaderSize(sizeof(core_content_t));
+            cb += ElfNoteHeaderSize(pSolProc->cbCred);
+
+            if (pSolProc->pPriv)
+                cb += ElfNoteHeaderSize(PRIV_PRPRIV_SIZE(pSolProc->pPriv));   /* Ought to be same as cbPriv!? */
+
+            if (pSolProc->pcPrivImpl)
+                cb += ElfNoteHeaderSize(PRIV_IMPL_INFO_SIZE(pSolProc->pcPrivImpl));
+
+            cb += ElfNoteHeaderSize(strlen(pSolProc->szZoneName) + 1);
+            if (pSolProc->cbLdt > 0)
+                cb += ElfNoteHeaderSize(pSolProc->cbLdt);
+
+            PRTSOLCORETHREADINFO pThreadInfo = pSolProc->pThreadInfoHead;
+            while (pThreadInfo)
+            {
+                cb += ElfNoteHeaderSize(sizeof(lwpsinfo_t));
+                if (pThreadInfo->pStatus)
+                    cb += ElfNoteHeaderSize(sizeof(lwpstatus_t));
+
+                pThreadInfo = pThreadInfo->pNext;
+            }
+
+            break;
+        }
+
+        default:
+        {
+            CORELOGRELSYS((CORELOG_NAME "ElfNoteSectionSize: Unknown segment era %d\n", enmType));
+            break;
+        }
+    }
+
+    return cb;
+}
+
+
+/**
+ * Write the note section for the given era into the core file.
+ * Solaris has two types of program  header information (new and old).
+ *
+ * @param pSolCore          Pointer to the core object.
+ * @param enmType           Type of core file information required.
+ *
+ * @return IPRT status code.
+ */
+static int ElfWriteNoteSection(PRTSOLCORE pSolCore, RTSOLCORETYPE enmType)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    int rc = VERR_GENERAL_FAILURE;
+
+#ifdef RT_OS_SOLARIS
+    typedef int (*PFNELFWRITENOTEHDR)(PRTSOLCORE pSolCore, uint_t, const void *pcv, size_t cb);
+    typedef struct
+    {
+        const char        *pszType;
+        uint_t             Type;
+        const void        *pcv;
+        size_t             cb;
+    } ELFWRITENOTE;
+
+    switch (enmType)
+    {
+        case enmOldEra:
+        {
+            ELFWRITENOTE aElfNotes[] =
+            {
+                { "NT_PRPSINFO", NT_PRPSINFO, &pSolProc->ProcInfoOld,   sizeof(prpsinfo_t) },
+                { "NT_AUXV",     NT_AUXV,      pSolProc->pAuxVecs,      pSolProc->cAuxVecs * sizeof(auxv_t) },
+                { "NT_PLATFORM", NT_PLATFORM,  pSolProc->szPlatform,    strlen(pSolProc->szPlatform) + 1 }
+            };
+
+            for (unsigned i = 0; i < RT_ELEMENTS(aElfNotes); i++)
+            {
+                rc = ElfWriteNoteHeader(pSolCore, aElfNotes[i].Type, aElfNotes[i].pcv, aElfNotes[i].cb);
+                if (RT_FAILURE(rc))
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteNoteSection: ElfWriteNoteHeader failed for %s. rc=%Rrc\n",
+                                   aElfNotes[i].pszType, rc));
+                    break;
+                }
+            }
+
+            /*
+             * Write old-style thread info., they contain nothing about zombies,
+             * so we just skip if there is no status information for them.
+             */
+            PRTSOLCORETHREADINFO pThreadInfo = pSolProc->pThreadInfoHead;
+            for (; pThreadInfo; pThreadInfo = pThreadInfo->pNext)
+            {
+                if (!pThreadInfo->pStatus)
+                    continue;
+
+                prstatus_t OldProcessStatus;
+                GetOldProcessStatus(pSolCore, &pThreadInfo->Info, pThreadInfo->pStatus, &OldProcessStatus);
+                rc = ElfWriteNoteHeader(pSolCore, NT_PRSTATUS, &OldProcessStatus, sizeof(prstatus_t));
+                if (RT_SUCCESS(rc))
+                {
+                    rc = ElfWriteNoteHeader(pSolCore, NT_PRFPREG, &pThreadInfo->pStatus->pr_fpreg, sizeof(prfpregset_t));
+                    if (RT_FAILURE(rc))
+                    {
+                        CORELOGRELSYS((CORELOG_NAME "ElfWriteSegment: ElfWriteNote failed for NT_PRFPREF. rc=%Rrc\n", rc));
+                        break;
+                    }
+                }
+                else
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteSegment: ElfWriteNote failed for NT_PRSTATUS. rc=%Rrc\n", rc));
+                    break;
+                }
+            }
+            break;
+        }
+
+        case enmNewEra:
+        {
+            ELFWRITENOTE aElfNotes[] =
+            {
+                { "NT_PSINFO",     NT_PSINFO,      pSolProc->pvProcInfo,   pSolProc->cbProcInfo },
+                { "NT_PSTATUS",    NT_PSTATUS,    &pSolProc->ProcStatus,   sizeof(pstatus_t) },
+                { "NT_AUXV",       NT_AUXV,        pSolProc->pAuxVecs,     pSolProc->cAuxVecs * sizeof(auxv_t) },
+                { "NT_PLATFORM",   NT_PLATFORM,    pSolProc->szPlatform,   strlen(pSolProc->szPlatform) + 1 },
+                { "NT_UTSNAME",    NT_UTSNAME,    &pSolProc->UtsName,      sizeof(struct utsname) },
+                { "NT_CONTENT",    NT_CONTENT,    &pSolProc->CoreContent,  sizeof(core_content_t) },
+                { "NT_PRCRED",     NT_PRCRED,      pSolProc->pvCred,       pSolProc->cbCred },
+                { "NT_PRPRIV",     NT_PRPRIV,      pSolProc->pPriv,        PRIV_PRPRIV_SIZE(pSolProc->pPriv) },
+                { "NT_PRPRIVINFO", NT_PRPRIVINFO,  pSolProc->pcPrivImpl,   PRIV_IMPL_INFO_SIZE(pSolProc->pcPrivImpl) },
+                { "NT_ZONENAME",   NT_ZONENAME,    pSolProc->szZoneName,   strlen(pSolProc->szZoneName) + 1 }
+            };
+
+            for (unsigned i = 0; i < RT_ELEMENTS(aElfNotes); i++)
+            {
+                rc = ElfWriteNoteHeader(pSolCore, aElfNotes[i].Type, aElfNotes[i].pcv, aElfNotes[i].cb);
+                if (RT_FAILURE(rc))
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteNoteSection: ElfWriteNoteHeader failed for %s. rc=%Rrc\n",
+                                   aElfNotes[i].pszType, rc));
+                    break;
+                }
+            }
+
+            /*
+             * Write new-style thread info., missing lwpstatus_t indicates it's a zombie thread
+             * we only dump the lwpsinfo_t in that case.
+             */
+            PRTSOLCORETHREADINFO pThreadInfo = pSolProc->pThreadInfoHead;
+            for (; pThreadInfo; pThreadInfo = pThreadInfo->pNext)
+            {
+                rc = ElfWriteNoteHeader(pSolCore, NT_LWPSINFO, &pThreadInfo->Info, sizeof(lwpsinfo_t));
+                if (RT_FAILURE(rc))
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteNoteSection: ElfWriteNoteHeader for NT_LWPSINFO failed. rc=%Rrc\n", rc));
+                    break;
+                }
+
+                if (pThreadInfo->pStatus)
+                {
+                    rc = ElfWriteNoteHeader(pSolCore, NT_LWPSTATUS, pThreadInfo->pStatus, sizeof(lwpstatus_t));
+                    if (RT_FAILURE(rc))
+                    {
+                        CORELOGRELSYS((CORELOG_NAME "ElfWriteNoteSection: ElfWriteNoteHeader for NT_LWPSTATUS failed. rc=%Rrc\n",
+                                       rc));
+                        break;
+                    }
+                }
+            }
+            break;
+        }
+
+        default:
+        {
+            CORELOGRELSYS((CORELOG_NAME "ElfWriteNoteSection: Invalid type %d\n", enmType));
+            rc = VERR_GENERAL_FAILURE;
+            break;
+        }
+    }
+#else
+# error Port Me!
+#endif
+    return rc;
+}
+
+
+/**
+ * Write mappings into the core file.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int ElfWriteMappings(PRTSOLCORE pSolCore)
+{
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+
+    int rc = VERR_GENERAL_FAILURE;
+    PRTSOLCOREMAPINFO pMapInfo = pSolProc->pMapInfoHead;
+    while (pMapInfo)
+    {
+        if (!pMapInfo->fError)
+        {
+            uint64_t k = 0;
+            char achBuf[PAGE_SIZE];
+            while (k < pMapInfo->pMap.pr_size)
+            {
+                size_t cb = RT_MIN(sizeof(achBuf), pMapInfo->pMap.pr_size - k);
+                int rc2 = ProcReadAddrSpace(pSolProc, pMapInfo->pMap.pr_vaddr + k, &achBuf, cb);
+                if (RT_FAILURE(rc2))
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteMappings: Failed to read mapping, can't recover. Bye. rc=%Rrc\n", rc));
+                    return VERR_INVALID_STATE;
+                }
+
+                rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, achBuf, sizeof(achBuf));
+                if (RT_FAILURE(rc))
+                {
+                    CORELOGRELSYS((CORELOG_NAME "ElfWriteMappings: pfnWriter failed. rc=%Rrc\n", rc));
+                    return rc;
+                }
+                k += cb;
+            }
+        }
+        else
+        {
+            char achBuf[RT_ALIGN_Z(sizeof(int), 8)];
+            RT_ZERO(achBuf);
+            memcpy(achBuf, &pMapInfo->fError, sizeof(pMapInfo->fError));
+            if (sizeof(achBuf) != pMapInfo->pMap.pr_size)
+                CORELOGRELSYS((CORELOG_NAME "ElfWriteMappings: Huh!? something is wrong!\n"));
+            rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &achBuf, sizeof(achBuf));
+            if (RT_FAILURE(rc))
+            {
+                CORELOGRELSYS((CORELOG_NAME "ElfWriteMappings: pfnWriter(2) failed. rc=%Rrc\n", rc));
+                return rc;
+            }
+        }
+
+        pMapInfo = pMapInfo->pNext;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Write program headers for all mappings into the core file.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int ElfWriteMappingHeaders(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    Elf_Phdr ProgHdr;
+    RT_ZERO(ProgHdr);
+    ProgHdr.p_type = PT_LOAD;
+
+    int rc = VERR_GENERAL_FAILURE;
+    PRTSOLCOREMAPINFO pMapInfo = pSolProc->pMapInfoHead;
+    while (pMapInfo)
+    {
+        ProgHdr.p_vaddr  = pMapInfo->pMap.pr_vaddr;     /* Virtual address of this mapping in the process address space */
+        ProgHdr.p_offset = pSolCore->offWrite;          /* Where this mapping is located in the core file */
+        ProgHdr.p_memsz  = pMapInfo->pMap.pr_size;      /* Size of the memory image of the mapping */
+        ProgHdr.p_filesz = pMapInfo->pMap.pr_size;      /* Size of the file image of the mapping */
+
+        ProgHdr.p_flags = 0;                            /* Reset fields in a loop when needed! */
+        if (pMapInfo->pMap.pr_mflags & MA_READ)
+            ProgHdr.p_flags |= PF_R;
+        if (pMapInfo->pMap.pr_mflags & MA_WRITE)
+            ProgHdr.p_flags |= PF_W;
+        if (pMapInfo->pMap.pr_mflags & MA_EXEC)
+            ProgHdr.p_flags |= PF_X;
+
+        if (pMapInfo->fError)
+            ProgHdr.p_flags |= PF_SUNW_FAILURE;
+
+        rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &ProgHdr, sizeof(ProgHdr));
+        if (RT_FAILURE(rc))
+        {
+            CORELOGRELSYS((CORELOG_NAME "ElfWriteMappingHeaders: pfnWriter failed. rc=%Rrc\n", rc));
+            return rc;
+        }
+
+        pSolCore->offWrite += ProgHdr.p_filesz;
+        pMapInfo = pMapInfo->pNext;
+    }
+    return rc;
+}
+
+/**
+ * Inner worker for rtCoreDumperWriteCore, which purpose is to
+ * squash cleanup gotos.
+ */
+static int rtCoreDumperWriteCoreDoIt(PRTSOLCORE pSolCore, PFNRTCOREWRITER pfnWriter,
+                                     PRTSOLCOREPROCESS pSolProc)
+{
+    pSolCore->offWrite = 0;
+    uint32_t cProgHdrs = pSolProc->cMappings + 2; /* two PT_NOTE program headers (old, new style) */
+
+    /*
+     * Write the ELF header.
+     */
+    Elf_Ehdr ElfHdr;
+    RT_ZERO(ElfHdr);
+    ElfHdr.e_ident[EI_MAG0]  = ELFMAG0;
+    ElfHdr.e_ident[EI_MAG1]  = ELFMAG1;
+    ElfHdr.e_ident[EI_MAG2]  = ELFMAG2;
+    ElfHdr.e_ident[EI_MAG3]  = ELFMAG3;
+    ElfHdr.e_ident[EI_DATA]  = IsBigEndian() ? ELFDATA2MSB : ELFDATA2LSB;
+    ElfHdr.e_type            = ET_CORE;
+    ElfHdr.e_version         = EV_CURRENT;
+#ifdef RT_ARCH_AMD64
+    ElfHdr.e_machine         = EM_AMD64;
+    ElfHdr.e_ident[EI_CLASS] = ELFCLASS64;
+#else
+    ElfHdr.e_machine         = EM_386;
+    ElfHdr.e_ident[EI_CLASS] = ELFCLASS32;
+#endif
+    if (cProgHdrs >= PN_XNUM)
+        ElfHdr.e_phnum       = PN_XNUM;
+    else
+        ElfHdr.e_phnum       = cProgHdrs;
+    ElfHdr.e_ehsize          = sizeof(ElfHdr);
+    ElfHdr.e_phoff           = sizeof(ElfHdr);
+    ElfHdr.e_phentsize       = sizeof(Elf_Phdr);
+    ElfHdr.e_shentsize       = sizeof(Elf_Shdr);
+    int rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &ElfHdr, sizeof(ElfHdr));
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: pfnWriter failed writing ELF header. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Setup program header.
+     */
+    Elf_Phdr ProgHdr;
+    RT_ZERO(ProgHdr);
+    ProgHdr.p_type = PT_NOTE;
+    ProgHdr.p_flags = PF_R;
+
+    /*
+     * Write old-style NOTE program header.
+     */
+    pSolCore->offWrite += sizeof(ElfHdr) + cProgHdrs * sizeof(ProgHdr);
+    ProgHdr.p_offset = pSolCore->offWrite;
+    ProgHdr.p_filesz = ElfNoteSectionSize(pSolCore, enmOldEra);
+    rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &ProgHdr, sizeof(ProgHdr));
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: pfnWriter failed writing old-style ELF program Header. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Write new-style NOTE program header.
+     */
+    pSolCore->offWrite += ProgHdr.p_filesz;
+    ProgHdr.p_offset = pSolCore->offWrite;
+    ProgHdr.p_filesz = ElfNoteSectionSize(pSolCore, enmNewEra);
+    rc = pSolCore->pfnWriter(pSolCore->fdCoreFile, &ProgHdr, sizeof(ProgHdr));
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: pfnWriter failed writing new-style ELF program header. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Write program headers per mapping.
+     */
+    pSolCore->offWrite += ProgHdr.p_filesz;
+    rc = ElfWriteMappingHeaders(pSolCore);
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "Write: ElfWriteMappings failed. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Write old-style note section.
+     */
+    rc = ElfWriteNoteSection(pSolCore, enmOldEra);
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: ElfWriteNoteSection old-style failed. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Write new-style section.
+     */
+    rc = ElfWriteNoteSection(pSolCore, enmNewEra);
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: ElfWriteNoteSection new-style failed. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    /*
+     * Write all mappings.
+     */
+    rc = ElfWriteMappings(pSolCore);
+    if (RT_FAILURE(rc))
+    {
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: ElfWriteMappings failed. rc=%Rrc\n", rc));
+        return rc;
+    }
+
+    return rc;
+}
+
+
+/**
+ * Write a prepared core file using a user-passed in writer function, requires all threads
+ * to be in suspended state (i.e. called after CreateCore).
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to the core object.
+ * @param pfnWriter         Pointer to the writer function to override default writer (NULL uses default).
+ *
+ * @remarks Resumes all suspended threads, unless it's an invalid core. This
+ *          function must be called only -after- rtCoreDumperCreateCore().
+ */
+static int rtCoreDumperWriteCore(PRTSOLCORE pSolCore, PFNRTCOREWRITER pfnWriter)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+
+    if (!pSolCore->fIsValid)
+        return VERR_INVALID_STATE;
+
+    if (pfnWriter)
+        pSolCore->pfnWriter = pfnWriter;
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    char szPath[PATH_MAX];
+    int  rc;
+
+    /*
+     * Open the process address space file.
+     */
+    RTStrPrintf(szPath, sizeof(szPath), "/proc/%d/as", (int)pSolProc->Process);
+    int fd = open(szPath, O_RDONLY);
+    if (fd >= 0)
+    {
+        pSolProc->fdAs = fd;
+
+        /*
+         * Create the core file.
+         */
+        fd = open(pSolCore->szCorePath, O_CREAT | O_TRUNC | O_RDWR, S_IRUSR);
+        if (fd >= 0)
+        {
+            pSolCore->fdCoreFile = fd;
+
+            /*
+             * Do the actual writing.
+             */
+            rc = rtCoreDumperWriteCoreDoIt(pSolCore, pfnWriter, pSolProc);
+
+            close(pSolCore->fdCoreFile);
+            pSolCore->fdCoreFile = -1;
+        }
+        else
+        {
+            rc = RTErrConvertFromErrno(fd);
+            CORELOGRELSYS((CORELOG_NAME "WriteCore: failed to open %s. rc=%Rrc\n", pSolCore->szCorePath, rc));
+        }
+        close(pSolProc->fdAs);
+        pSolProc->fdAs = -1;
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(fd);
+        CORELOGRELSYS((CORELOG_NAME "WriteCore: Failed to open address space, %s. rc=%Rrc\n", szPath, rc));
+    }
+
+    rtCoreDumperResumeThreads(pSolCore);
+    return rc;
+}
+
+
+/**
+ * Takes a process snapshot into a passed-in core object. It has the side-effect of halting
+ * all threads which can lead to things like spurious wakeups of threads (if and when threads
+ * are ultimately resumed en-masse) already suspended while calling this function.
+ *
+ * @return IPRT status code.
+ * @param pSolCore          Pointer to a core object.
+ * @param pContext          Pointer to the caller context thread.
+ * @param pszCoreFilePath   Path to the core file. If NULL is passed, the global
+ *                          path specified in RTCoreDumperSetup() would be used.
+ *
+ * @remarks Halts all threads.
+ */
+static int rtCoreDumperCreateCore(PRTSOLCORE pSolCore, ucontext_t *pContext, const char *pszCoreFilePath)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+    AssertReturn(pContext, VERR_INVALID_POINTER);
+
+    /*
+     * Initialize core structures.
+     */
+    memset(pSolCore, 0, sizeof(RTSOLCORE));
+    pSolCore->pfnReader = &ReadFileNoIntr;
+    pSolCore->pfnWriter = &WriteFileNoIntr;
+    pSolCore->fIsValid  = false;
+    pSolCore->fdCoreFile = -1;
+
+    PRTSOLCOREPROCESS pSolProc = &pSolCore->SolProc;
+    pSolProc->Process        = RTProcSelf();
+    pSolProc->hCurThread     = _lwp_self(); /* thr_self() */
+    pSolProc->fdAs           = -1;
+    pSolProc->pCurThreadCtx  = pContext;
+    pSolProc->CoreContent    = CC_CONTENT_DEFAULT;
+
+    RTProcGetExecutablePath(pSolProc->szExecPath, sizeof(pSolProc->szExecPath));  /* this gets full path not just name */
+    pSolProc->pszExecName = RTPathFilename(pSolProc->szExecPath);
+
+    /*
+     * If a path has been specified, use it. Otherwise use the global path.
+     */
+    if (!pszCoreFilePath)
+    {
+        /*
+         * If no output directory is specified, use current directory.
+         */
+        if (g_szCoreDumpDir[0] == '\0')
+            g_szCoreDumpDir[0] = '.';
+
+        if (g_szCoreDumpFile[0] == '\0')
+        {
+            /* We cannot call RTPathAbs*() as they call getcwd() which calls malloc. */
+            RTStrPrintf(pSolCore->szCorePath, sizeof(pSolCore->szCorePath), "%s/core.vb.%s.%d",
+                        g_szCoreDumpDir, pSolProc->pszExecName, (int)pSolProc->Process);
+        }
+        else
+            RTStrPrintf(pSolCore->szCorePath, sizeof(pSolCore->szCorePath), "%s/core.vb.%s", g_szCoreDumpDir, g_szCoreDumpFile);
+    }
+    else
+        RTStrCopy(pSolCore->szCorePath, sizeof(pSolCore->szCorePath), pszCoreFilePath);
+
+    CORELOG((CORELOG_NAME  "CreateCore: Taking Core %s from Thread %d\n", pSolCore->szCorePath, (int)pSolProc->hCurThread));
+
+    /*
+     * Quiesce the process.
+     */
+    int rc = rtCoreDumperSuspendThreads(pSolCore);
+    if (RT_SUCCESS(rc))
+    {
+        rc = AllocMemoryArea(pSolCore);
+        if (RT_SUCCESS(rc))
+        {
+            rc = ProcReadInfo(pSolCore);
+            if (RT_SUCCESS(rc))
+            {
+                rc = GetOldProcessInfo(pSolCore, &pSolProc->ProcInfoOld);
+                if (RT_SUCCESS(rc))
+                {
+                    if (IsProcessArchNative(pSolProc))
+                    {
+                        /*
+                         * Read process status, information such as number of active LWPs will be
+                         * invalid since we just quiesced the process.
+                         */
+                        rc = ProcReadStatus(pSolCore);
+                        if (RT_SUCCESS(rc))
+                        {
+                            struct COREACCUMULATOR
+                            {
+                                const char        *pszName;
+                                PFNRTSOLCOREACCUMULATOR pfnAcc;
+                                bool               fOptional;
+                            } aAccumulators[] =
+                            {
+                                { "ProcReadLdt",      &ProcReadLdt,      false },
+                                { "ProcReadCred",     &ProcReadCred,     false },
+                                { "ProcReadPriv",     &ProcReadPriv,     false },
+                                { "ProcReadAuxVecs",  &ProcReadAuxVecs,  false },
+                                { "ProcReadMappings", &ProcReadMappings, false },
+                                { "ProcReadThreads",  &ProcReadThreads,  false },
+                                { "ProcReadMiscInfo", &ProcReadMiscInfo, false }
+                            };
+
+                            for (unsigned i = 0; i < RT_ELEMENTS(aAccumulators); i++)
+                            {
+                                rc = aAccumulators[i].pfnAcc(pSolCore);
+                                if (RT_FAILURE(rc))
+                                {
+                                    CORELOGRELSYS((CORELOG_NAME "CreateCore: %s failed. rc=%Rrc\n", aAccumulators[i].pszName, rc));
+                                    if (!aAccumulators[i].fOptional)
+                                        break;
+                                }
+                            }
+
+                            if (RT_SUCCESS(rc))
+                            {
+                                pSolCore->fIsValid = true;
+                                return VINF_SUCCESS;
+                            }
+
+                            FreeMemoryArea(pSolCore);
+                        }
+                        else
+                            CORELOGRELSYS((CORELOG_NAME "CreateCore: ProcReadStatus failed. rc=%Rrc\n", rc));
+                    }
+                    else
+                    {
+                        CORELOGRELSYS((CORELOG_NAME "CreateCore: IsProcessArchNative failed.\n"));
+                        rc = VERR_BAD_EXE_FORMAT;
+                    }
+                }
+                else
+                    CORELOGRELSYS((CORELOG_NAME "CreateCore: GetOldProcessInfo failed. rc=%Rrc\n", rc));
+            }
+            else
+                CORELOGRELSYS((CORELOG_NAME "CreateCore: ProcReadInfo failed. rc=%Rrc\n", rc));
+        }
+        else
+            CORELOGRELSYS((CORELOG_NAME "CreateCore: AllocMemoryArea failed. rc=%Rrc\n", rc));
+
+        /*
+         * Resume threads on failure.
+         */
+        rtCoreDumperResumeThreads(pSolCore);
+    }
+    else
+        CORELOG((CORELOG_NAME "CreateCore: SuspendAllThreads failed. Thread bomb!?! rc=%Rrc\n", rc));
+
+    return rc;
+}
+
+
+/**
+ * Destroy an existing core object.
+ *
+ * @param pSolCore          Pointer to the core object.
+ *
+ * @return IPRT status code.
+ */
+static int rtCoreDumperDestroyCore(PRTSOLCORE pSolCore)
+{
+    AssertReturn(pSolCore, VERR_INVALID_POINTER);
+    if (!pSolCore->fIsValid)
+        return VERR_INVALID_STATE;
+
+    FreeMemoryArea(pSolCore);
+    pSolCore->fIsValid = false;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Takes a core dump.
+ *
+ * @param   pContext            The context of the caller.
+ * @param   pszOutputFile       Path of the core file. If NULL is passed, the
+ *                              global path passed in RTCoreDumperSetup will
+ *                              be used.
+ * @returns IPRT status code.
+ */
+static int rtCoreDumperTakeDump(ucontext_t *pContext, const char *pszOutputFile)
+{
+    if (!pContext)
+    {
+        CORELOGRELSYS((CORELOG_NAME "TakeDump: Missing context.\n"));
+        return VERR_INVALID_POINTER;
+    }
+
+    /*
+     * Take a snapshot, then dump core to disk, all threads except this one are halted
+     * from before taking the snapshot until writing the core is completely finished.
+     * Any errors would resume all threads if they were halted.
+     */
+    RTSOLCORE SolCore;
+    RT_ZERO(SolCore);
+    int rc = rtCoreDumperCreateCore(&SolCore, pContext, pszOutputFile);
+    if (RT_SUCCESS(rc))
+    {
+        rc = rtCoreDumperWriteCore(&SolCore, &WriteFileNoIntr);
+        if (RT_SUCCESS(rc))
+            CORELOGRELSYS((CORELOG_NAME "Core dumped in %s\n", SolCore.szCorePath));
+        else
+            CORELOGRELSYS((CORELOG_NAME "TakeDump: WriteCore failed. szCorePath=%s rc=%Rrc\n", SolCore.szCorePath, rc));
+
+        rtCoreDumperDestroyCore(&SolCore);
+    }
+    else
+        CORELOGRELSYS((CORELOG_NAME "TakeDump: CreateCore failed. rc=%Rrc\n", rc));
+
+    return rc;
+}
+
+
+/**
+ * The signal handler that will be invoked to take core dumps.
+ *
+ * @param Sig                   The signal that invoked us.
+ * @param pSigInfo              The signal information.
+ * @param pvArg                 Opaque pointer to the caller context structure,
+ *                              this cannot be NULL.
+ */
+static void rtCoreDumperSignalHandler(int Sig, siginfo_t *pSigInfo, void *pvArg)
+{
+    CORELOG((CORELOG_NAME "SignalHandler Sig=%d pvArg=%p\n", Sig, pvArg));
+
+    RTNATIVETHREAD  hCurNativeThread = RTThreadNativeSelf();
+    int             rc               = VERR_GENERAL_FAILURE;
+    bool            fCallSystemDump  = false;
+    bool            fRc;
+    ASMAtomicCmpXchgHandle(&g_CoreDumpThread, hCurNativeThread, NIL_RTNATIVETHREAD, fRc);
+    if (fRc)
+    {
+        rc = rtCoreDumperTakeDump((ucontext_t *)pvArg, NULL /* Use Global Core filepath */);
+        ASMAtomicWriteHandle(&g_CoreDumpThread, NIL_RTNATIVETHREAD);
+
+        if (RT_FAILURE(rc))
+            CORELOGRELSYS((CORELOG_NAME "TakeDump failed! rc=%Rrc\n", rc));
+    }
+    else if (Sig == SIGSEGV || Sig == SIGBUS || Sig == SIGTRAP)
+    {
+        /*
+         * Core dumping is already in progress and we've somehow ended up being
+         * signalled again.
+         */
+        rc = VERR_INTERNAL_ERROR;
+
+        /*
+         * If our dumper has crashed. No point in waiting, trigger the system one.
+         * Wait only when the dumping thread is not the one generating this signal.
+         */
+        RTNATIVETHREAD hNativeDumperThread;
+        ASMAtomicReadHandle(&g_CoreDumpThread, &hNativeDumperThread);
+        if (hNativeDumperThread == RTThreadNativeSelf())
+        {
+            CORELOGRELSYS((CORELOG_NAME "SignalHandler: Core dumper (thread %u) crashed Sig=%d. Triggering system dump\n",
+                           RTThreadSelf(), Sig));
+            fCallSystemDump = true;
+        }
+        else
+        {
+            /*
+             * Some other thread in the process is triggering a crash, wait a while
+             * to let our core dumper finish, on timeout trigger system dump.
+             */
+            CORELOGRELSYS((CORELOG_NAME "SignalHandler: Core dump already in progress! Waiting a while for completion Sig=%d.\n",
+                           Sig));
+            int64_t iTimeout = 16000;  /* timeout (ms) */
+            for (;;)
+            {
+                ASMAtomicReadHandle(&g_CoreDumpThread, &hNativeDumperThread);
+                if (hNativeDumperThread == NIL_RTNATIVETHREAD)
+                    break;
+                RTThreadSleep(200);
+                iTimeout -= 200;
+                if (iTimeout <= 0)
+                    break;
+            }
+            if (iTimeout <= 0)
+            {
+                fCallSystemDump = true;
+                CORELOGRELSYS((CORELOG_NAME "SignalHandler: Core dumper seems to be stuck. Signalling new signal %d\n", Sig));
+            }
+        }
+    }
+
+    if (Sig == SIGSEGV || Sig == SIGBUS || Sig == SIGTRAP)
+    {
+        /*
+         * Reset signal handlers, we're not a live core we will be blown away
+         * one way or another.
+         */
+        signal(SIGSEGV, SIG_DFL);
+        signal(SIGBUS, SIG_DFL);
+        signal(SIGTRAP, SIG_DFL);
+
+        /*
+         * Hard terminate the process if this is not a live dump without invoking
+         * the system core dumping behaviour.
+         */
+        if (RT_SUCCESS(rc))
+            raise(SIGKILL);
+
+        /*
+         * Something went wrong, fall back to the system core dumper.
+         */
+        if (fCallSystemDump)
+            abort();
+    }
+}
+
+
+RTDECL(int) RTCoreDumperTakeDump(const char *pszOutputFile, bool fLiveCore)
+{
+    ucontext_t Context;
+    int rc = getcontext(&Context);
+    if (!rc)
+    {
+        /*
+         * Block SIGSEGV and co. while we write the core.
+         */
+        sigset_t SigSet, OldSigSet;
+        sigemptyset(&SigSet);
+        sigaddset(&SigSet, SIGSEGV);
+        sigaddset(&SigSet, SIGBUS);
+        sigaddset(&SigSet, SIGTRAP);
+        sigaddset(&SigSet, SIGUSR2);
+        pthread_sigmask(SIG_BLOCK, &SigSet, &OldSigSet);
+        rc = rtCoreDumperTakeDump(&Context, pszOutputFile);
+        if (RT_FAILURE(rc))
+            CORELOGRELSYS(("RTCoreDumperTakeDump: rtCoreDumperTakeDump failed rc=%Rrc\n", rc));
+
+        if (!fLiveCore)
+        {
+            signal(SIGSEGV, SIG_DFL);
+            signal(SIGBUS, SIG_DFL);
+            signal(SIGTRAP, SIG_DFL);
+            if (RT_SUCCESS(rc))
+                raise(SIGKILL);
+            else
+                abort();
+        }
+        pthread_sigmask(SIG_SETMASK, &OldSigSet, NULL);
+    }
+    else
+    {
+        CORELOGRELSYS(("RTCoreDumperTakeDump: getcontext failed rc=%d.\n", rc));
+        rc = VERR_INVALID_CONTEXT;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTCoreDumperSetup(const char *pszOutputDir, uint32_t fFlags)
+{
+    /*
+     * Validate flags.
+     */
+    AssertReturn(fFlags, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~(  RTCOREDUMPER_FLAGS_REPLACE_SYSTEM_DUMP
+                              | RTCOREDUMPER_FLAGS_LIVE_CORE)),
+                 VERR_INVALID_PARAMETER);
+
+
+    /*
+     * Setup/change the core dump directory if specified.
+     */
+    RT_ZERO(g_szCoreDumpDir);
+    if (pszOutputDir)
+    {
+        if (!RTDirExists(pszOutputDir))
+            return VERR_NOT_A_DIRECTORY;
+        RTStrCopy(g_szCoreDumpDir, sizeof(g_szCoreDumpDir), pszOutputDir);
+    }
+
+    /*
+     * Install core dump signal handler only if the flags changed or if it's the first time.
+     */
+    if (   ASMAtomicReadBool(&g_fCoreDumpSignalSetup) == false
+        || ASMAtomicReadU32(&g_fCoreDumpFlags) != fFlags)
+    {
+        struct sigaction sigAct;
+        RT_ZERO(sigAct);
+        sigAct.sa_sigaction = &rtCoreDumperSignalHandler;
+
+        if (   (fFlags & RTCOREDUMPER_FLAGS_REPLACE_SYSTEM_DUMP)
+            && !(g_fCoreDumpFlags & RTCOREDUMPER_FLAGS_REPLACE_SYSTEM_DUMP))
+        {
+            sigemptyset(&sigAct.sa_mask);
+            sigAct.sa_flags = SA_RESTART | SA_SIGINFO | SA_NODEFER;
+            sigaction(SIGSEGV, &sigAct, NULL);
+            sigaction(SIGBUS, &sigAct, NULL);
+            sigaction(SIGTRAP, &sigAct, NULL);
+        }
+
+        if (   fFlags & RTCOREDUMPER_FLAGS_LIVE_CORE
+            && !(g_fCoreDumpFlags & RTCOREDUMPER_FLAGS_LIVE_CORE))
+        {
+            sigfillset(&sigAct.sa_mask);                        /* Block all signals while in it's signal handler */
+            sigAct.sa_flags = SA_RESTART | SA_SIGINFO;
+            sigaction(SIGUSR2, &sigAct, NULL);
+        }
+
+        ASMAtomicWriteU32(&g_fCoreDumpFlags, fFlags);
+        ASMAtomicWriteBool(&g_fCoreDumpSignalSetup, true);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTCoreDumperDisable(void)
+{
+    /*
+     * Remove core dump signal handler & reset variables.
+     */
+    if (ASMAtomicReadBool(&g_fCoreDumpSignalSetup) == true)
+    {
+        signal(SIGSEGV, SIG_DFL);
+        signal(SIGBUS, SIG_DFL);
+        signal(SIGTRAP, SIG_DFL);
+        signal(SIGUSR2, SIG_DFL);
+        ASMAtomicWriteBool(&g_fCoreDumpSignalSetup, false);
+    }
+
+    RT_ZERO(g_szCoreDumpDir);
+    RT_ZERO(g_szCoreDumpFile);
+    ASMAtomicWriteU32(&g_fCoreDumpFlags, 0);
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/coredumper-solaris.h b/src/VBox/Runtime/r3/solaris/coredumper-solaris.h
new file mode 100644
index 00000000..4583eb4d
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/coredumper-solaris.h
@@ -0,0 +1,177 @@
+/* $Id: coredumper-solaris.h $ */
+/** @file
+ * IPRT - Custom Core Dumper, Solaris.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_solaris_coredumper_solaris_h
+#define IPRT_INCLUDED_SRC_r3_solaris_coredumper_solaris_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#include <iprt/types.h>
+
+#ifdef RT_OS_SOLARIS
+# if defined(RT_ARCH_X86) && _FILE_OFFSET_BITS==64
+/*
+ * Solaris' procfs cannot be used with large file environment in 32-bit.
+ */
+# undef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 32
+# include <procfs.h>
+# include <sys/procfs.h>
+# include <sys/old_procfs.h>
+# undef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#else
+# include <procfs.h>
+# include <sys/procfs.h>
+# include <sys/old_procfs.h>
+#endif
+# include <limits.h>
+# include <thread.h>
+# include <sys/auxv.h>
+# include <sys/lwp.h>
+# include <sys/zone.h>
+# include <sys/utsname.h>
+
+#ifdef RT_ARCH_AMD64
+# define _ELF64
+# undef _ELF32_COMPAT
+#endif
+# include <sys/corectl.h>
+#endif
+
+
+#ifdef RT_OS_SOLARIS
+/**
+ * Memory mapping descriptor employed by the solaris core dumper.
+ */
+typedef struct RTSOLCOREMAPINFO
+{
+    prmap_t                         pMap;                       /**< Proc description of this mapping */
+    int                             fError;                     /**< Any error reading this mapping (errno) */
+    struct RTSOLCOREMAPINFO        *pNext;                      /**< Pointer to the next mapping */
+} RTSOLCOREMAPINFO;
+/** Pointer to a solaris memory mapping descriptor. */
+typedef RTSOLCOREMAPINFO *PRTSOLCOREMAPINFO;
+
+/**
+ * Whether this is an old or new style solaris core.
+ */
+typedef enum RTSOLCORETYPE
+{
+    enmOldEra = 0x01d,   /**< old */
+    enmNewEra = 0x5c1f1  /**< sci-fi */
+} RTSOLCORETYPE;
+
+/**
+ * Per-Thread information employed by the solaris core dumper.
+ */
+typedef struct RTSOLCORETHREADINFO
+{
+    lwpsinfo_t                      Info;                       /**< Proc description of this thread */
+    lwpstatus_t                    *pStatus;                    /**< Proc description of this thread's status (can be NULL, zombie lwp) */
+    struct RTSOLCORETHREADINFO     *pNext;                      /**< Pointer to the next thread */
+} RTSOLCORETHREADINFO;
+typedef RTSOLCORETHREADINFO *PRTSOLCORETHREADINFO;
+#endif
+
+
+/**
+ * Current (also the core target) process information.
+ */
+typedef struct RTSOLCOREPROCESS
+{
+    RTPROCESS                       Process;                    /**< The pid of the process */
+    char                            szExecPath[PATH_MAX];       /**< Path of the executable */
+    char                           *pszExecName;                /**< Name of the executable file */
+#ifdef RT_OS_SOLARIS
+    void                           *pvProcInfo;                 /**< Process info. */
+    size_t                          cbProcInfo;                 /**< Size of the process info. */
+    prpsinfo_t                      ProcInfoOld;                /**< Process info. Older version (for GDB compat.) */
+    pstatus_t                       ProcStatus;                 /**< Process status info. */
+    thread_t                        hCurThread;                 /**< The current thread */
+    ucontext_t                     *pCurThreadCtx;              /**< Context info. of current thread before starting to dump */
+    int                             fdAs;                       /**< proc/pid/as file handle */
+    auxv_t                         *pAuxVecs;                   /**< Aux vector of process */
+    int                             cAuxVecs;                   /**< Number of aux vector entries */
+    PRTSOLCOREMAPINFO               pMapInfoHead;               /**< Pointer to the head of list of mappings */
+    uint32_t                        cMappings;                  /**< Number of mappings (count of pMapInfoHead list) */
+    PRTSOLCORETHREADINFO            pThreadInfoHead;            /**< Pointer to the head of list of threads */
+    uint64_t                        cThreads;                   /**< Number of threads (count of pThreadInfoHead list) */
+    char                            szPlatform[SYS_NMLN];       /**< Platform name  */
+    char                            szZoneName[ZONENAME_MAX];   /**< Zone name */
+    struct utsname                  UtsName;                    /**< UTS name */
+    void                           *pvCred;                     /**< Process credential info. */
+    size_t                          cbCred;                     /**< Size of process credential info. */
+    void                           *pvLdt;                      /**< Process LDT info. */
+    size_t                          cbLdt;                      /**< Size of the LDT info. */
+    prpriv_t                       *pPriv;                      /**< Process privilege info. */
+    size_t                          cbPriv;                     /**< Size of process privilege info. */
+    const priv_impl_info_t         *pcPrivImpl;                 /**< Process privilege implementation info. (opaque handle) */
+    core_content_t                  CoreContent;                /**< What information goes in the core */
+#else
+# error Port Me!
+#endif
+
+} RTSOLCOREPROCESS;
+typedef RTSOLCOREPROCESS *PRTSOLCOREPROCESS;
+
+typedef int (*PFNRTCOREREADER)(int fdFile, void *pv, size_t cb);
+typedef int (*PFNRTCOREWRITER)(int fdhFile, const void *pcv, size_t cb);
+
+/**
+ * The solaris core file object.
+ */
+typedef struct RTSOLCORE
+{
+    char                            szCorePath[PATH_MAX];       /**< Path of the core file */
+    RTSOLCOREPROCESS                SolProc;                    /**< Current process information */
+    void                           *pvCore;                     /**< Pointer to memory area during dumping */
+    size_t                          cbCore;                     /**< Size of memory area during dumping */
+    void                           *pvFree;                     /**< Pointer to base of free range in preallocated memory area */
+    bool                            fIsValid;                   /**< Whether core information has been fully collected */
+    PFNRTCOREREADER                 pfnReader;                  /**< Reader function */
+    PFNRTCOREWRITER                 pfnWriter;                  /**< Writer function */
+    int                             fdCoreFile;                 /**< Core file (used only while writing the core) */
+    RTFOFF                          offWrite;                   /**< Segment/section offset (used only while writing the core) */
+} RTSOLCORE;
+typedef RTSOLCORE *PRTSOLCORE;
+
+typedef int (*PFNRTSOLCOREACCUMULATOR)(PRTSOLCORE pSolCore);
+typedef int (*PFNRTSOLCORETHREADWORKER)(PRTSOLCORE pSolCore, void *pvThreadInfo);
+
+#endif /* !IPRT_INCLUDED_SRC_r3_solaris_coredumper_solaris_h */
+
diff --git a/src/VBox/Runtime/r3/solaris/fileaio-solaris.cpp b/src/VBox/Runtime/r3/solaris/fileaio-solaris.cpp
new file mode 100644
index 00000000..f129d4fc
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/fileaio-solaris.cpp
@@ -0,0 +1,574 @@
+/* $Id: fileaio-solaris.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for the Solaris host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FILE
+#include <iprt/asm.h>
+#include <iprt/file.h>
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/fileaio.h"
+
+#include <port.h>
+#include <aio.h>
+#include <errno.h>
+#include <unistd.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** Handle to the port. */
+    int               iPort;
+    /** Current number of requests active on this context. */
+    volatile int32_t  cRequests;
+    /** Flags given during creation. */
+    uint32_t          fFlags;
+    /** Magic value (RTFILEAIOCTX_MAGIC). */
+    uint32_t          u32Magic;
+} RTFILEAIOCTXINTERNAL;
+/** Pointer to an internal context structure. */
+typedef RTFILEAIOCTXINTERNAL *PRTFILEAIOCTXINTERNAL;
+
+/**
+ * Async I/O request state.
+ */
+typedef struct RTFILEAIOREQINTERNAL
+{
+    /** The aio control block. Must be the FIRST
+     *  element. */
+    struct aiocb           AioCB;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE      enmState;
+    /** Flag whether this is a flush request. */
+    bool                   fFlush;
+    /** Port notifier object to associate a request to a port. */
+    port_notify_t          PortNotifier;
+    /** Opaque user data. */
+    void                  *pvUser;
+    /** Completion context we are assigned to. */
+    PRTFILEAIOCTXINTERNAL  pCtxInt;
+    /** Magic value  (RTFILEAIOREQ_MAGIC). */
+    uint32_t               u32Magic;
+} RTFILEAIOREQINTERNAL;
+/** Pointer to an internal request structure. */
+typedef RTFILEAIOREQINTERNAL *PRTFILEAIOREQINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The max number of events to get in one call. */
+#define AIO_MAXIMUM_REQUESTS_PER_CONTEXT 64
+/** Id for the wakeup event. */
+#define AIO_CONTEXT_WAKEUP_EVENT 1
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    int rcBSD = 0;
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+    /* No limits known. */
+    pAioLimits->cReqsOutstandingMax = RTFILEAIO_UNLIMITED_REQS;
+    pAioLimits->cbBufferAlignment   = 0;
+
+    return VINF_SUCCESS;
+}
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOREQINTERNAL));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    /* Ininitialize static parts. */
+    pReqInt->AioCB.aio_sigevent.sigev_notify = SIGEV_PORT;
+    pReqInt->AioCB.aio_sigevent.sigev_value.sival_ptr = &pReqInt->PortNotifier;
+    pReqInt->PortNotifier.portnfy_user = pReqInt;
+    pReqInt->pCtxInt                   = NULL;
+    pReqInt->u32Magic                  = RTFILEAIOREQ_MAGIC;
+    RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+    *phReq = (RTFILEAIOREQ)pReqInt;
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
+{
+    /*
+     * Validate the handle and ignore nil.
+     */
+    if (hReq == NIL_RTFILEAIOREQ)
+        return VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    /*
+     * Trash the magic and free it.
+     */
+    ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
+    RTMemFree(pReqInt);
+    return VINF_SUCCESS;
+}
+
+/**
+ * Worker setting up the request.
+ */
+DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
+                                            unsigned uTransferDirection,
+                                            RTFOFF off, void *pvBuf, size_t cbTransfer,
+                                            void *pvUser)
+{
+    /*
+     * Validate the input.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+    AssertPtr(pvBuf);
+    Assert(off >= 0);
+    Assert(cbTransfer > 0);
+
+    pReqInt->AioCB.aio_lio_opcode = uTransferDirection;
+    pReqInt->AioCB.aio_fildes     = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset     = off;
+    pReqInt->AioCB.aio_nbytes     = cbTransfer;
+    pReqInt->AioCB.aio_buf        = pvBuf;
+    pReqInt->fFlush               = false;
+    pReqInt->pvUser               = pvUser;
+    pReqInt->pCtxInt              = NULL;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                    void *pvBuf, size_t cbRead, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_READ,
+                                       off, pvBuf, cbRead, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                     void const *pvBuf, size_t cbWrite, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, LIO_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)hReq;
+
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+
+    pReqInt->fFlush           = true;
+    pReqInt->AioCB.aio_fildes = RTFileToNative(hFile);
+    pReqInt->AioCB.aio_offset = 0;
+    pReqInt->AioCB.aio_nbytes = 0;
+    pReqInt->AioCB.aio_buf    = NULL;
+    pReqInt->pvUser           = pvUser;
+    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->pvUser;
+}
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    int rcSolaris = aio_cancel(pReqInt->AioCB.aio_fildes, &pReqInt->AioCB);
+
+    if (rcSolaris == AIO_CANCELED)
+    {
+        /*
+         * Decrement request count because the request will never arrive at the
+         * completion port.
+         */
+        AssertMsg(RT_VALID_PTR(pReqInt->pCtxInt), ("Invalid state. Request was canceled but wasn't submitted\n"));
+
+        ASMAtomicDecS32(&pReqInt->pCtxInt->cRequests);
+        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+        return VINF_SUCCESS;
+    }
+    else if (rcSolaris == AIO_ALLDONE)
+        return VERR_FILE_AIO_COMPLETED;
+    else if (rcSolaris == AIO_NOTCANCELED)
+        return VERR_FILE_AIO_IN_PROGRESS;
+    else
+        return RTErrConvertFromErrno(errno);
+}
+
+RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
+    AssertPtrNull(pcbTransfered);
+
+    int rcSol = aio_error(&pReqInt->AioCB);
+    Assert(rcSol != EINPROGRESS); /* Handled by our own state handling. */
+
+    if (rcSol == 0)
+    {
+        if (pcbTransfered)
+            *pcbTransfered = aio_return(&pReqInt->AioCB);
+        return VINF_SUCCESS;
+    }
+
+    /* An error occurred. */
+    return RTErrConvertFromErrno(rcSol);
+}
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax,
+                               uint32_t fFlags)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
+    if (RT_UNLIKELY(!pCtxInt))
+        return VERR_NO_MEMORY;
+
+    /* Init the event handle. */
+    pCtxInt->iPort = port_create();
+    if (RT_LIKELY(pCtxInt->iPort > 0))
+    {
+        pCtxInt->fFlags   = fFlags;
+        pCtxInt->u32Magic = RTFILEAIOCTX_MAGIC;
+        *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+    }
+    else
+    {
+        RTMemFree(pCtxInt);
+        rc = RTErrConvertFromErrno(errno);
+    }
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
+{
+    /* Validate the handle and ignore nil. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /* Cannot destroy a busy context. */
+    if (RT_UNLIKELY(pCtxInt->cRequests))
+        return VERR_FILE_AIO_BUSY;
+
+    close(pCtxInt->iPort);
+    ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    return RTFILEAIO_UNLIMITED_REQS;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    /*
+     * Parameter validation.
+     */
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertReturn(cReqs > 0,  VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    size_t i = cReqs;
+
+    do
+    {
+        int rcSol = 0;
+        size_t cReqsSubmit = 0;
+        PRTFILEAIOREQINTERNAL pReqInt;
+
+        while(i-- > 0)
+        {
+            pReqInt = pahReqs[i];
+            if (RTFILEAIOREQ_IS_NOT_VALID(pReqInt))
+            {
+                /* Undo everything and stop submitting. */
+                for (size_t iUndo = 0; iUndo < i; iUndo++)
+                {
+                    pReqInt = pahReqs[iUndo];
+                    RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                    pReqInt->pCtxInt = NULL;
+                }
+                rc = VERR_INVALID_HANDLE;
+                break;
+            }
+
+            pReqInt->PortNotifier.portnfy_port = pCtxInt->iPort;
+            pReqInt->pCtxInt                   = pCtxInt;
+            RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+
+            if (pReqInt->fFlush)
+                break;
+
+            cReqsSubmit++;
+        }
+
+        if (cReqsSubmit)
+        {
+            rcSol = lio_listio(LIO_NOWAIT, (struct aiocb **)pahReqs, cReqsSubmit, NULL);
+            if (RT_UNLIKELY(rcSol < 0))
+            {
+                if (rcSol == EAGAIN)
+                    rc = VERR_FILE_AIO_INSUFFICIENT_RESSOURCES;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+
+                /* Check which requests got actually submitted and which not. */
+                for (i = 0; i < cReqs; i++)
+                {
+                    pReqInt = pahReqs[i];
+                    rcSol = aio_error(&pReqInt->AioCB);
+                    if (rcSol == EINVAL)
+                    {
+                        /* Was not submitted. */
+                        RTFILEAIOREQ_SET_STATE(pReqInt, PREPARED);
+                        pReqInt->pCtxInt = NULL;
+                    }
+                    else if (rcSol != EINPROGRESS)
+                    {
+                        /* The request encountered an error. */
+                        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                    }
+                }
+                break;
+            }
+
+            ASMAtomicAddS32(&pCtxInt->cRequests, cReqsSubmit);
+            cReqs   -= cReqsSubmit;
+            pahReqs += cReqsSubmit;
+        }
+
+        if (cReqs)
+        {
+            pReqInt = pahReqs[0];
+            RTFILEAIOREQ_VALID_RETURN(pReqInt);
+
+            /*
+             * If there are still requests left we have a flush request.
+             * lio_listio does not work with this requests so
+             * we have to use aio_fsync directly.
+             */
+            rcSol = aio_fsync(O_SYNC, &pReqInt->AioCB);
+            if (RT_UNLIKELY(rcSol < 0))
+            {
+                RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+                rc = RTErrConvertFromErrno(errno);
+                break;
+            }
+
+            ASMAtomicIncS32(&pCtxInt->cRequests);
+            cReqs--;
+            pahReqs++;
+        }
+    } while (cReqs);
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+
+    /*
+     * Validate the parameters, making sure to always set pcReqs.
+     */
+    AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
+    *pcReqs = 0; /* always set */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
+    AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
+
+    if (    RT_UNLIKELY(ASMAtomicReadS32(&pCtxInt->cRequests) == 0)
+        && !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
+        return VERR_FILE_AIO_NO_REQUEST;
+
+    /*
+     * Convert the timeout if specified.
+     */
+    struct timespec    *pTimeout = NULL;
+    struct timespec     Timeout = {0,0};
+    uint64_t            StartNanoTS = 0;
+    if (cMillies != RT_INDEFINITE_WAIT)
+    {
+        Timeout.tv_sec  = cMillies / 1000;
+        Timeout.tv_nsec = cMillies % 1000 * 1000000;
+        pTimeout = &Timeout;
+        StartNanoTS = RTTimeNanoTS();
+    }
+
+    /* Wait for at least one. */
+    if (!cMinReqs)
+        cMinReqs = 1;
+
+    while (   cMinReqs
+           && RT_SUCCESS_NP(rc))
+    {
+        port_event_t aPortEvents[AIO_MAXIMUM_REQUESTS_PER_CONTEXT];
+        uint_t cRequests    = cMinReqs;
+        int cRequestsToWait = RT_MIN(cReqs, AIO_MAXIMUM_REQUESTS_PER_CONTEXT);
+        int rcSol;
+        uint64_t StartTime;
+
+        rcSol = port_getn(pCtxInt->iPort, &aPortEvents[0], cRequestsToWait, &cRequests, pTimeout);
+
+        if (RT_UNLIKELY(rcSol < 0))
+            rc = RTErrConvertFromErrno(errno);
+
+        /* Process received events. */
+        for (uint_t i = 0; i < cRequests; i++)
+        {
+            if (aPortEvents[i].portev_source == PORT_SOURCE_ALERT)
+            {
+                Assert(aPortEvents[i].portev_events == AIO_CONTEXT_WAKEUP_EVENT);
+                rc = VERR_INTERRUPTED; /* We've got interrupted. */
+                /* Reset the port. */
+                port_alert(pCtxInt->iPort, PORT_ALERT_SET, 0, NULL);
+            }
+            else
+            {
+                PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)aPortEvents[i].portev_user;
+                AssertPtr(pReqInt);
+                Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
+
+                /* A request has finished. */
+                pahReqs[cRequestsCompleted++] = pReqInt;
+
+                /* Mark the request as finished. */
+                RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+            }
+        }
+
+        /*
+         * Done Yet? If not advance and try again.
+         */
+        if (cRequests >= cMinReqs)
+            break;
+        cMinReqs -= cRequests;
+        cReqs    -= cRequests;
+
+        if (cMillies != RT_INDEFINITE_WAIT)
+        {
+            uint64_t NanoTS = RTTimeNanoTS();
+            uint64_t cMilliesElapsed = (NanoTS - StartNanoTS) / 1000000;
+
+            /* The syscall supposedly updates it, but we're paranoid. :-) */
+            if (cMilliesElapsed < cMillies)
+            {
+                Timeout.tv_sec  = (cMillies - (RTMSINTERVAL)cMilliesElapsed) / 1000;
+                Timeout.tv_nsec = (cMillies - (RTMSINTERVAL)cMilliesElapsed) % 1000 * 1000000;
+            }
+            else
+            {
+                Timeout.tv_sec  = 0;
+                Timeout.tv_nsec = 0;
+            }
+        }
+    }
+
+    /*
+     * Update the context state and set the return value.
+     */
+    *pcReqs = cRequestsCompleted;
+    ASMAtomicSubS32(&pCtxInt->cRequests, cRequestsCompleted);
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    rc = port_alert(pCtxInt->iPort, PORT_ALERT_UPDATE, AIO_CONTEXT_WAKEUP_EVENT, NULL);
+    if (RT_UNLIKELY((rc < 0) && (errno != EBUSY)))
+        return RTErrConvertFromErrno(errno);
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/krnlmod-solaris.cpp b/src/VBox/Runtime/r3/solaris/krnlmod-solaris.cpp
new file mode 100644
index 00000000..bb02ac55
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/krnlmod-solaris.cpp
@@ -0,0 +1,358 @@
+/* $Id: krnlmod-solaris.cpp $ */
+/** @file
+ * IPRT - Kernel module, Linux.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/krnlmod.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/dir.h>
+#include <iprt/errcore.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/types.h>
+
+#include <iprt/stream.h>
+
+#include <sys/modctl.h>
+#include <errno.h>
+
+/**
+ * Internal kernel information record state.
+ */
+typedef struct RTKRNLMODINFOINT
+{
+    /** Reference counter. */
+    volatile uint32_t   cRefs;
+    /** Load address of the kernel module. */
+    RTR0UINTPTR         uLoadAddr;
+    /** Size of the kernel module. */
+    size_t              cbKrnlMod;
+    /** Size of the name in characters including the zero terminator. */
+    size_t              cchName;
+    /** Module name - variable in size. */
+    char                achName[1];
+} RTKRNLMODINFOINT;
+/** Pointer to the internal kernel module information record. */
+typedef RTKRNLMODINFOINT *PRTKRNLMODINFOINT;
+/** Pointer to a const internal kernel module information record. */
+typedef const RTKRNLMODINFOINT *PCRTKRNLMODINFOINT;
+
+
+
+/**
+ * Destroy the given kernel module information record.
+ *
+ * @param   pThis            The record to destroy.
+ */
+static void rtKrnlModInfoDestroy(PRTKRNLMODINFOINT pThis)
+{
+    RTMemFree(pThis);
+}
+
+
+/**
+ * Creates a new kernel module information record for the given module.
+ *
+ * @returns IPRT status code.
+ * @param   pModInfo         The Solaris kernel module information.
+ * @param   phKrnlModInfo    Where to store the handle to the kernel module information record
+ *                           on success.
+ */
+static int rtKrnlModSolInfoCreate(struct modinfo *pModInfo, PRTKRNLMODINFO phKrnlModInfo)
+{
+    int rc = VINF_SUCCESS;
+    size_t cchName = strlen(&pModInfo->mi_name[0]) + 1;
+    PRTKRNLMODINFOINT pThis = (PRTKRNLMODINFOINT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTKRNLMODINFOINT, achName[cchName]));
+    if (RT_LIKELY(pThis))
+    {
+        memcpy(&pThis->achName[0], &pModInfo->mi_name[0], cchName);
+        pThis->cchName     = cchName;
+        pThis->cRefs       = 1;
+        pThis->cbKrnlMod   = pModInfo->mi_size;
+        pThis->uLoadAddr   = (RTR0UINTPTR)pModInfo->mi_base;
+
+        *phKrnlModInfo = pThis;
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModQueryLoaded(const char *pszName, bool *pfLoaded)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfLoaded, VERR_INVALID_POINTER);
+
+    RTKRNLMODINFO hKrnlModInfo = NIL_RTKRNLMODINFO;
+    int rc = RTKrnlModLoadedQueryInfo(pszName, &hKrnlModInfo);
+    if (RT_SUCCESS(rc))
+    {
+        *pfLoaded = true;
+        RTKrnlModInfoRelease(hKrnlModInfo);
+    }
+    else if (rc == VERR_NOT_FOUND)
+    {
+        *pfLoaded = false;
+        rc = VINF_SUCCESS;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfo(const char *pszName, PRTKRNLMODINFO phKrnlModInfo)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(phKrnlModInfo, VERR_INVALID_POINTER);
+
+    int rc = VERR_NOT_FOUND;
+    int iId = -1;
+    struct modinfo ModInfo;
+
+    ModInfo.mi_info   = MI_INFO_ALL | MI_INFO_CNT;
+    ModInfo.mi_id     = iId;
+    ModInfo.mi_nextid = iId;
+    do
+    {
+        int rcSol = modctl(MODINFO, iId, &ModInfo);
+        if (rcSol < 0)
+        {
+            rc = RTErrConvertFromErrno(errno);
+            break;
+        }
+
+        if (ModInfo.mi_id != -1)
+        {
+            ModInfo.mi_name[MODMAXNAMELEN - 1] = '\0'; /* Paranoia. */
+            if (!RTStrCmp(pszName, &ModInfo.mi_name[0]))
+            {
+                rc = rtKrnlModSolInfoCreate(&ModInfo, phKrnlModInfo);
+                break;
+            }
+        }
+
+        iId = ModInfo.mi_id;
+    } while (iId != -1);
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModLoadedGetCount(void)
+{
+    uint32_t cKmodsLoaded = 0;
+    int iId = -1;
+    struct modinfo ModInfo;
+
+    ModInfo.mi_info   = MI_INFO_ALL | MI_INFO_CNT;
+    ModInfo.mi_id     = iId;
+    ModInfo.mi_nextid = iId;
+    do
+    {
+        int rcSol = modctl(MODINFO, iId, &ModInfo);
+        if (rcSol < 0)
+            break;
+
+        cKmodsLoaded++;
+
+        iId = ModInfo.mi_id;
+    } while (iId != -1);
+
+    return cKmodsLoaded;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfoAll(PRTKRNLMODINFO pahKrnlModInfo, uint32_t cEntriesMax,
+                                        uint32_t *pcEntries)
+{
+    if (cEntriesMax > 0)
+        AssertPtrReturn(pahKrnlModInfo, VERR_INVALID_POINTER);
+
+    uint32_t cKmodsLoaded = RTKrnlModLoadedGetCount();
+    if (cEntriesMax < cKmodsLoaded)
+    {
+        if (*pcEntries)
+            *pcEntries = cKmodsLoaded;
+        return VERR_BUFFER_OVERFLOW;
+    }
+
+    int rc = VINF_SUCCESS;
+    int iId = -1;
+    unsigned idxKrnlModInfo = 0;
+    struct modinfo ModInfo;
+
+    ModInfo.mi_info   = MI_INFO_ALL | MI_INFO_CNT;
+    ModInfo.mi_id     = iId;
+    ModInfo.mi_nextid = iId;
+    do
+    {
+        int rcSol = modctl(MODINFO, iId, &ModInfo);
+        if (rcSol < 0)
+        {
+            rc = RTErrConvertFromErrno(errno);
+            if (rc == VERR_INVALID_PARAMETER && idxKrnlModInfo > 0)
+                rc = VINF_SUCCESS;
+            break;
+        }
+
+        ModInfo.mi_name[MODMAXNAMELEN - 1] = '\0'; /* Paranoia. */
+        rc = rtKrnlModSolInfoCreate(&ModInfo, &pahKrnlModInfo[idxKrnlModInfo]);
+        if (RT_SUCCESS(rc))
+            idxKrnlModInfo++;
+
+        iId = ModInfo.mi_id;
+    } while (iId != -1);
+
+    if (RT_FAILURE(rc))
+    {
+        /* Rollback */
+        while (idxKrnlModInfo-- > 0)
+            RTKrnlModInfoRelease(pahKrnlModInfo[idxKrnlModInfo]);
+    }
+    else if (pcEntries)
+        *pcEntries = idxKrnlModInfo;
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRetain(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRelease(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    if (!pThis)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtKrnlModInfoDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoGetRefCnt(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return 0;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetName(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return &pThis->achName[0];
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetFilePath(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return NULL;
+}
+
+
+RTDECL(size_t) RTKrnlModInfoGetSize(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cbKrnlMod;
+}
+
+
+RTDECL(RTR0UINTPTR) RTKrnlModInfoGetLoadAddr(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->uLoadAddr;
+}
+
+
+RTDECL(int) RTKrnlModInfoQueryRefModInfo(RTKRNLMODINFO hKrnlModInfo, uint32_t idx,
+                                         PRTKRNLMODINFO phKrnlModInfoRef)
+{
+    RT_NOREF3(hKrnlModInfo, idx, phKrnlModInfoRef);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByPath(const char *pszPath)
+{
+    AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModUnloadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
diff --git a/src/VBox/Runtime/r3/solaris/mp-solaris.cpp b/src/VBox/Runtime/r3/solaris/mp-solaris.cpp
new file mode 100644
index 00000000..b412efae
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/mp-solaris.cpp
@@ -0,0 +1,479 @@
+/* $Id: mp-solaris.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, Solaris.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <kstat.h>
+#include <sys/processor.h>
+
+#include <iprt/mp.h>
+#include <iprt/cpuset.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/log.h>
+#include <iprt/once.h>
+#include <iprt/string.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Initialization serializing (rtMpSolarisOnce). */
+static RTONCE       g_MpSolarisOnce = RTONCE_INITIALIZER;
+/** Critical section serializing access to kstat. */
+static RTCRITSECT   g_MpSolarisCritSect;
+/** The kstat handle. */
+static kstat_ctl_t *g_pKsCtl;
+/** Array pointing to the cpu_info instances. */
+static kstat_t    **g_papCpuInfo;
+/** The number of entries in g_papCpuInfo */
+static RTCPUID      g_capCpuInfo;
+/** Array of core ids.  */
+static uint64_t    *g_pu64CoreIds;
+/** Number of entries in g_pu64CoreIds. */
+static size_t       g_cu64CoreIds;
+/** Number of cores in the system. */
+static size_t       g_cCores;
+
+
+/**
+ * Helper for getting the core ID for a given CPU/strand/hyperthread.
+ *
+ * @returns The core ID.
+ * @param   idCpu       The CPU ID instance.
+ */
+static inline uint64_t rtMpSolarisGetCoreId(RTCPUID idCpu)
+{
+    kstat_named_t *pStat = (kstat_named_t *)kstat_data_lookup(g_papCpuInfo[idCpu], (char *)"core_id");
+    Assert(pStat->data_type == KSTAT_DATA_LONG);
+    Assert(pStat->value.l >= 0);
+    AssertCompile(sizeof(uint64_t) >= sizeof(long));    /* Paranoia. */
+    return (uint64_t)pStat->value.l;
+}
+
+
+/**
+ * Populates 'g_pu64CoreIds' array with unique core identifiers in the system.
+ *
+ * @returns VBox status code.
+ */
+static int rtMpSolarisGetCoreIds(void)
+{
+    for (RTCPUID idCpu = 0; idCpu < g_capCpuInfo; idCpu++)
+    {
+        /*
+         * It is possible that the number of cores don't match the maximum number
+         * of cores possible on the system. Hence check if we have a valid cpu_info
+         * object. We don't want to break out if it's NULL, the array may be sparse
+         * in theory, see @bugref{8469}.
+         */
+        if (g_papCpuInfo[idCpu])
+        {
+            if (kstat_read(g_pKsCtl, g_papCpuInfo[idCpu], 0) != -1)
+            {
+                /* Strands/Hyperthreads share the same core ID. */
+                uint64_t u64CoreId  = rtMpSolarisGetCoreId(idCpu);
+                bool     fAddedCore = false;
+                for (RTCPUID i = 0; i < g_cCores; i++)
+                {
+                    if (g_pu64CoreIds[i] == u64CoreId)
+                    {
+                        fAddedCore = true;
+                        break;
+                    }
+                }
+
+                if (!fAddedCore)
+                {
+                    g_pu64CoreIds[g_cCores] = u64CoreId;
+                    ++g_cCores;
+                }
+            }
+            else
+                return VERR_INTERNAL_ERROR_2;
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Run once function that initializes the kstats we need here.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser      Unused.
+ */
+static DECLCALLBACK(int) rtMpSolarisOnce(void *pvUser)
+{
+    int rc = VINF_SUCCESS;
+    NOREF(pvUser);
+
+    /*
+     * Open kstat and find the cpu_info entries for each of the CPUs.
+     */
+    g_pKsCtl = kstat_open();
+    if (g_pKsCtl)
+    {
+        g_capCpuInfo = RTMpGetCount();
+        if (RT_LIKELY(g_capCpuInfo > 0))
+        {
+            g_papCpuInfo = (kstat_t **)RTMemAllocZ(g_capCpuInfo * sizeof(kstat_t *));
+            if (g_papCpuInfo)
+            {
+                g_cu64CoreIds = g_capCpuInfo;
+                g_pu64CoreIds = (uint64_t *)RTMemAllocZ(g_cu64CoreIds * sizeof(uint64_t));
+                if (g_pu64CoreIds)
+                {
+                    rc = RTCritSectInit(&g_MpSolarisCritSect);
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTCPUID i = 0;
+                        for (kstat_t *pKsp = g_pKsCtl->kc_chain; pKsp != NULL; pKsp = pKsp->ks_next)
+                        {
+                            if (!RTStrCmp(pKsp->ks_module, "cpu_info"))
+                            {
+                                AssertBreak(i < g_capCpuInfo);
+                                g_papCpuInfo[i++] = pKsp;
+                                /** @todo ks_instance == cpu_id (/usr/src/uts/common/os/cpu.c)? Check this and fix it ASAP. */
+                            }
+                        }
+
+                        rc = rtMpSolarisGetCoreIds();
+                        if (RT_SUCCESS(rc))
+                            return VINF_SUCCESS;
+                        else
+                            Log(("rtMpSolarisGetCoreIds failed. rc=%Rrc\n", rc));
+                    }
+
+                    RTMemFree(g_pu64CoreIds);
+                    g_pu64CoreIds = NULL;
+                }
+                else
+                    rc = VERR_NO_MEMORY;
+
+                /* bail out, we failed. */
+                RTMemFree(g_papCpuInfo);
+                g_papCpuInfo = NULL;
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+        else
+            rc = VERR_CPU_IPE_1;
+        kstat_close(g_pKsCtl);
+        g_pKsCtl = NULL;
+    }
+    else
+    {
+        rc = RTErrConvertFromErrno(errno);
+        if (RT_SUCCESS(rc))
+            rc = VERR_INTERNAL_ERROR;
+        Log(("kstat_open() -> %d (%Rrc)\n", errno, rc));
+    }
+
+    return rc;
+}
+
+
+/**
+ * RTOnceEx() cleanup function.
+ *
+ * @param   pvUser              Unused.
+ * @param   fLazyCleanUpOk      Whether lazy cleanup is okay or not.
+ */
+static DECLCALLBACK(void) rtMpSolarisCleanUp(void *pvUser, bool fLazyCleanUpOk)
+{
+    if (g_pKsCtl)
+        kstat_close(g_pKsCtl);
+    RTMemFree(g_pu64CoreIds);
+    RTMemFree(g_papCpuInfo);
+}
+
+
+/**
+ * Worker for RTMpGetCurFrequency and RTMpGetMaxFrequency.
+ *
+ * @returns The desired frequency on success, 0 on failure.
+ *
+ * @param   idCpu           The CPU ID.
+ * @param   pszStatName     The cpu_info stat name.
+ */
+static uint64_t rtMpSolarisGetFrequency(RTCPUID idCpu, const char *pszStatName)
+{
+    uint64_t u64 = 0;
+    int rc = RTOnceEx(&g_MpSolarisOnce, rtMpSolarisOnce, rtMpSolarisCleanUp, NULL /* pvUser */);
+    if (RT_SUCCESS(rc))
+    {
+        if (    idCpu < g_capCpuInfo
+            &&  g_papCpuInfo[idCpu])
+        {
+            rc = RTCritSectEnter(&g_MpSolarisCritSect);
+            AssertRC(rc);
+            if (RT_SUCCESS(rc))
+            {
+                if (kstat_read(g_pKsCtl, g_papCpuInfo[idCpu], 0) != -1)
+                {
+                    /* Solaris really need to fix their APIs. Explicitly cast for now. */
+                    kstat_named_t *pStat = (kstat_named_t *)kstat_data_lookup(g_papCpuInfo[idCpu], (char*)pszStatName);
+                    if (pStat)
+                    {
+                        Assert(pStat->data_type == KSTAT_DATA_UINT64 || pStat->data_type == KSTAT_DATA_LONG);
+                        switch (pStat->data_type)
+                        {
+                            case KSTAT_DATA_UINT64: u64 = pStat->value.ui64; break; /* current_clock_Hz */
+                            case KSTAT_DATA_INT32:  u64 = pStat->value.i32;  break; /* clock_MHz */
+
+                            /* just in case... */
+                            case KSTAT_DATA_UINT32: u64 = pStat->value.ui32; break;
+                            case KSTAT_DATA_INT64:  u64 = pStat->value.i64;  break;
+                            default:
+                                AssertMsgFailed(("%d\n", pStat->data_type));
+                                break;
+                        }
+                    }
+                    else
+                        Log(("kstat_data_lookup(%s) -> %d\n", pszStatName, errno));
+                }
+                else
+                    Log(("kstat_read() -> %d\n", errno));
+                RTCritSectLeave(&g_MpSolarisCritSect);
+            }
+        }
+        else
+            Log(("invalid idCpu: %d (g_capCpuInfo=%d)\n", (int)idCpu, (int)g_capCpuInfo));
+    }
+
+    return u64;
+}
+
+
+RTDECL(uint32_t) RTMpGetCurFrequency(RTCPUID idCpu)
+{
+    return rtMpSolarisGetFrequency(idCpu, "current_clock_Hz") / 1000000;
+}
+
+
+RTDECL(uint32_t) RTMpGetMaxFrequency(RTCPUID idCpu)
+{
+    return rtMpSolarisGetFrequency(idCpu, "clock_MHz");
+}
+
+
+#if defined(RT_ARCH_SPARC) || defined(RT_ARCH_SPARC64)
+RTDECL(RTCPUID) RTMpCpuId(void)
+{
+    /** @todo implement RTMpCpuId on solaris/r3! */
+    return NIL_RTCPUID;
+}
+#endif
+
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    return idCpu < RTCPUSET_MAX_CPUS ? (int)idCpu : -1;
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    return (unsigned)iCpu < RTCPUSET_MAX_CPUS ? iCpu : NIL_RTCPUID;
+}
+
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    return RTMpGetCount() - 1;
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    return idCpu != NIL_RTCPUID
+        && idCpu < (RTCPUID)RTMpGetCount();
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+    int iStatus = p_online(idCpu, P_STATUS);
+    return iStatus == P_ONLINE
+        || iStatus == P_NOINTR;
+}
+
+
+RTDECL(bool) RTMpIsCpuPresent(RTCPUID idCpu)
+{
+    int iStatus = p_online(idCpu, P_STATUS);
+    return iStatus != -1;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    /*
+     * Solaris has sysconf.
+     */
+    int cCpus = sysconf(_SC_NPROCESSORS_MAX);
+    if (cCpus < 0)
+        cCpus = sysconf(_SC_NPROCESSORS_CONF);
+    return cCpus;
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    int idCpu = RTMpGetCount();
+    while (idCpu-- > 0)
+        RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+    /*
+     * Solaris has sysconf.
+     */
+    return sysconf(_SC_NPROCESSORS_ONLN);
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    RTCpuSetEmpty(pSet);
+    RTCPUID cCpus = RTMpGetCount();
+    for (RTCPUID idCpu = 0; idCpu < cCpus; idCpu++)
+        if (RTMpIsCpuOnline(idCpu))
+            RTCpuSetAdd(pSet, idCpu);
+    return pSet;
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetPresentSet(PRTCPUSET pSet)
+{
+#ifdef RT_STRICT
+    RTCPUID cCpusPresent = 0;
+#endif
+    RTCpuSetEmpty(pSet);
+    RTCPUID cCpus = RTMpGetCount();
+    for (RTCPUID idCpu = 0; idCpu < cCpus; idCpu++)
+        if (RTMpIsCpuPresent(idCpu))
+        {
+            RTCpuSetAdd(pSet, idCpu);
+#ifdef RT_STRICT
+            cCpusPresent++;
+#endif
+        }
+    Assert(cCpusPresent == RTMpGetPresentCount());
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetPresentCount(void)
+{
+    /*
+     * Solaris has sysconf.
+     */
+    return sysconf(_SC_NPROCESSORS_CONF);
+}
+
+
+RTDECL(RTCPUID) RTMpGetPresentCoreCount(void)
+{
+    return RTMpGetCoreCount();
+}
+
+
+RTDECL(RTCPUID) RTMpGetCoreCount(void)
+{
+    int rc = RTOnceEx(&g_MpSolarisOnce, rtMpSolarisOnce, rtMpSolarisCleanUp, NULL /* pvUser */);
+    if (RT_SUCCESS(rc))
+        return g_cCores;
+
+    return 0;
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCoreCount(void)
+{
+    RTCPUID uOnlineCores = 0;
+    int rc = RTOnceEx(&g_MpSolarisOnce, rtMpSolarisOnce, rtMpSolarisCleanUp, NULL /* pvUser */);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTCritSectEnter(&g_MpSolarisCritSect);
+        AssertRC(rc);
+
+        /*
+         * For each core in the system, count how many are currently online.
+         */
+        for (RTCPUID j = 0; j < g_cCores; j++)
+        {
+            uint64_t u64CoreId = g_pu64CoreIds[j];
+            for (RTCPUID idCpu = 0; idCpu < g_capCpuInfo; idCpu++)
+            {
+                rc = kstat_read(g_pKsCtl, g_papCpuInfo[idCpu], 0);
+                AssertReturn(rc != -1, 0 /* rc */);
+                uint64_t u64ThreadCoreId = rtMpSolarisGetCoreId(idCpu);
+                if (u64ThreadCoreId == u64CoreId)
+                {
+                    kstat_named_t *pStat = (kstat_named_t *)kstat_data_lookup(g_papCpuInfo[idCpu], (char *)"state");
+                    Assert(pStat->data_type == KSTAT_DATA_CHAR);
+                    if(   !RTStrNCmp(pStat->value.c, PS_ONLINE, sizeof(PS_ONLINE) - 1)
+                       || !RTStrNCmp(pStat->value.c, PS_NOINTR, sizeof(PS_NOINTR) - 1))
+                    {
+                        uOnlineCores++;
+                        break;      /* Move to the next core. We have at least 1 hyperthread online in the current core. */
+                    }
+                }
+            }
+        }
+
+        RTCritSectLeave(&g_MpSolarisCritSect);
+    }
+
+    return uOnlineCores;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/rtProcInitExePath-solaris.cpp b/src/VBox/Runtime/r3/solaris/rtProcInitExePath-solaris.cpp
new file mode 100644
index 00000000..0cf236b0
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/rtProcInitExePath-solaris.cpp
@@ -0,0 +1,81 @@
+/* $Id: rtProcInitExePath-solaris.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, Solaris.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <unistd.h>
+#include <errno.h>
+
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include "internal/process.h"
+#include "internal/path.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Read the /proc/<pid>/path/a.out link, convert to native and return it.
+     */
+    char szProcFile[80];
+    RTStrPrintf(szProcFile, sizeof(szProcFile), "/proc/%ld/path/a.out", (long)getpid());
+    int cchLink = readlink(szProcFile, pszPath, cchPath - 1);
+    if (cchLink > 0 && (size_t)cchLink <= cchPath - 1)
+    {
+        pszPath[cchLink] = '\0';
+
+        char const *pszTmp;
+        int rc = rtPathFromNative(&pszTmp, pszPath, NULL);
+        AssertMsgRCReturn(rc, ("rc=%Rrc pszLink=\"%s\"\nhex: %.*Rhxs\n", rc, pszPath, cchLink, pszPath), rc);
+        if (pszTmp != pszPath)
+        {
+            rc = RTStrCopy(pszPath, cchPath, pszTmp);
+            rtPathFreeIprt(pszTmp, pszPath);
+        }
+        return rc;
+    }
+
+    int err = errno;
+    int rc = RTErrConvertFromErrno(err);
+    AssertMsgFailed(("rc=%Rrc err=%d cchLink=%d\n", rc, err, cchLink));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/systemmem-solaris.cpp b/src/VBox/Runtime/r3/solaris/systemmem-solaris.cpp
new file mode 100644
index 00000000..b083c4f0
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/systemmem-solaris.cpp
@@ -0,0 +1,182 @@
+/* $Id: systemmem-solaris.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, Solaris ring-3.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/once.h>
+#include <iprt/param.h>
+
+#include <errno.h>
+#include <kstat.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Initialize globals once. */
+static RTONCE           g_rtSysMemSolInitOnce = RTONCE_INITIALIZER;
+/** Critical section serializing access to g_pKStatCtl and the other handles. */
+static RTCRITSECT       g_rtSysMemSolCritSect;
+/** The kstate control handle. */
+static kstat_ctl_t     *g_pKStatCtl     = NULL;
+/** The unix.system_pages handle. */
+static kstat_t         *g_pUnixSysPages = NULL;
+/** The zfs.archstats handle. */
+static kstat_t         *g_pZfsArcStats  = NULL;
+
+
+/** @callback_method_impl{FNRTONCE} */
+static DECLCALLBACK(int) rtSysMemSolInit(void *pvUser)
+{
+    int rc = RTCritSectInit(&g_rtSysMemSolCritSect);
+    if (RT_SUCCESS(rc))
+    {
+        g_pKStatCtl = kstat_open();
+        if (g_pKStatCtl)
+        {
+            g_pUnixSysPages = kstat_lookup(g_pKStatCtl, (char *)"unix", 0, (char *)"system_pages");
+            if (g_pUnixSysPages)
+            {
+                g_pZfsArcStats = kstat_lookup(g_pKStatCtl, (char *)"zfs",  0, (char *)"arcstats"); /* allow NULL */
+                return VINF_SUCCESS;
+            }
+
+            rc = RTErrConvertFromErrno(errno);
+            kstat_close(g_pKStatCtl);
+            g_pKStatCtl = NULL;
+        }
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+    return rc;
+}
+
+
+/** @callback_method_impl{FNRTONCECLEANUP} */
+static DECLCALLBACK(void) rtSysMemSolCleanUp(void *pvUser, bool fLazyCleanUpOk)
+{
+    RTCritSectDelete(&g_rtSysMemSolCritSect);
+
+    kstat_close(g_pKStatCtl);
+    g_pKStatCtl     = NULL;
+    g_pUnixSysPages = NULL;
+    g_pZfsArcStats  = NULL;
+
+    NOREF(pvUser); NOREF(fLazyCleanUpOk);
+}
+
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int rc = RTOnceEx(&g_rtSysMemSolInitOnce, rtSysMemSolInit, rtSysMemSolCleanUp, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTCritSectEnter(&g_rtSysMemSolCritSect);
+        if (RT_SUCCESS(rc))
+        {
+            if (kstat_read(g_pKStatCtl, g_pUnixSysPages, NULL) != -1)
+            {
+                kstat_named_t *pData = (kstat_named_t *)kstat_data_lookup(g_pUnixSysPages, (char *)"physmem");
+                if (pData)
+                    *pcb = (uint64_t)pData->value.ul * PAGE_SIZE;
+                else
+                    rc = RTErrConvertFromErrno(errno);
+            }
+            else
+                rc = RTErrConvertFromErrno(errno);
+            RTCritSectLeave(&g_rtSysMemSolCritSect);
+        }
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int rc = RTOnceEx(&g_rtSysMemSolInitOnce, rtSysMemSolInit, rtSysMemSolCleanUp, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTCritSectEnter(&g_rtSysMemSolCritSect);
+        if (RT_SUCCESS(rc))
+        {
+            if (kstat_read(g_pKStatCtl, g_pUnixSysPages, NULL) != -1)
+            {
+                kstat_named_t *pData = (kstat_named_t *)kstat_data_lookup(g_pUnixSysPages, (char *)"freemem");
+                if (pData)
+                {
+                    *pcb = (uint64_t)pData->value.ul * PAGE_SIZE;
+
+                    /*
+                     * Adjust for ZFS greedyness if possible.
+                     * (c_min is the target minimum size of the cache, it is not
+                     * an absolute minimum.)
+                     */
+                    if (   g_pZfsArcStats
+                        && kstat_read(g_pKStatCtl, g_pZfsArcStats, NULL) != -1)
+                    {
+                        kstat_named_t *pCurSize = (kstat_named_t *)kstat_data_lookup(g_pZfsArcStats, (char *)"size");
+                        kstat_named_t *pMinSize = (kstat_named_t *)kstat_data_lookup(g_pZfsArcStats, (char *)"c_min");
+                        if (   pCurSize
+                            && pMinSize
+                            && pCurSize->value.ul > pMinSize->value.ul)
+                        {
+                            *pcb += pCurSize->value.ul - pMinSize->value.ul;
+                        }
+                    }
+                }
+                else
+                    rc = RTErrConvertFromErrno(errno);
+            }
+
+            RTCritSectLeave(&g_rtSysMemSolCritSect);
+        }
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/solaris/thread-affinity-solaris.cpp b/src/VBox/Runtime/r3/solaris/thread-affinity-solaris.cpp
new file mode 100644
index 00000000..0e037aad
--- /dev/null
+++ b/src/VBox/Runtime/r3/solaris/thread-affinity-solaris.cpp
@@ -0,0 +1,104 @@
+/* $Id: thread-affinity-solaris.cpp $ */
+/** @file
+ * IPRT - Thread Affinity, Solaris ring-3 implementation.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/thread.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/cpuset.h>
+#include <iprt/err.h>
+#include <iprt/mp.h>
+
+#include <sys/types.h>
+#include <sys/processor.h>
+#include <sys/procset.h>
+#include <unistd.h>
+#include <errno.h>
+
+
+/* Note! The current implementation can only bind to a single CPU. */
+
+
+RTR3DECL(int) RTThreadSetAffinity(PCRTCPUSET pCpuSet)
+{
+    int rc;
+    if (pCpuSet == NULL)
+        rc = processor_bind(P_LWPID, P_MYID, PBIND_NONE, NULL);
+    else
+    {
+        RTCPUSET PresentSet;
+        int cCpusInSet = RTCpuSetCount(pCpuSet);
+        if (cCpusInSet == 1)
+        {
+            unsigned iCpu = 0;
+            while (   iCpu < RTCPUSET_MAX_CPUS
+                   && !RTCpuSetIsMemberByIndex(pCpuSet, iCpu))
+                iCpu++;
+            rc = processor_bind(P_LWPID, P_MYID, iCpu, NULL);
+        }
+        else if (   cCpusInSet == RTCPUSET_MAX_CPUS
+                 || RTCpuSetIsEqual(pCpuSet, RTMpGetPresentSet(&PresentSet)))
+            rc = processor_bind(P_LWPID, P_MYID, PBIND_NONE, NULL);
+        else
+            return VERR_NOT_SUPPORTED;
+    }
+    if (!rc)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+}
+
+
+RTR3DECL(int) RTThreadGetAffinity(PRTCPUSET pCpuSet)
+{
+    processorid_t iOldCpu;
+    int rc = processor_bind(P_LWPID, P_MYID, PBIND_QUERY, &iOldCpu);
+    if (rc)
+        return RTErrConvertFromErrno(errno);
+    if (iOldCpu == PBIND_NONE)
+        RTMpGetPresentSet(pCpuSet);
+    else
+    {
+        RTCpuSetEmpty(pCpuSet);
+        if (RTCpuSetAdd(pCpuSet, iOldCpu) != 0)
+            return VERR_INTERNAL_ERROR_5;
+    }
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/stream.cpp b/src/VBox/Runtime/r3/stream.cpp
new file mode 100644
index 00000000..ead09e53
--- /dev/null
+++ b/src/VBox/Runtime/r3/stream.cpp
@@ -0,0 +1,2698 @@
+/* $Id: stream.cpp $ */
+/** @file
+ * IPRT - I/O Stream.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @def RTSTREAM_STANDALONE
+ * Standalone streams w/o depending on stdio.h, using our RTFile API for
+ * file/whatever access. */
+#if (defined(IPRT_NO_CRT) && defined(RT_OS_WINDOWS)) || defined(DOXYGEN_RUNNING)
+# define RTSTREAM_STANDALONE
+#endif
+
+#if defined(RT_OS_LINUX) /* PORTME: check for the _unlocked functions in stdio.h */
+# ifndef RTSTREAM_STANDALONE
+#  define HAVE_FWRITE_UNLOCKED
+# endif
+#endif
+
+/** @def RTSTREAM_WITH_TEXT_MODE
+ * Indicates whether we need to support the 'text' mode files and convert
+ * CRLF to LF while reading and writing. */
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS) || defined(DOXYGEN_RUNNING)
+# define RTSTREAM_WITH_TEXT_MODE
+#endif
+
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/stream.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#ifndef HAVE_FWRITE_UNLOCKED
+# include <iprt/critsect.h>
+#endif
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+# include <iprt/file.h>
+#ifdef RTSTREAM_STANDALONE
+# include <iprt/list.h>
+#endif
+#include <iprt/mem.h>
+#ifdef RTSTREAM_STANDALONE
+# include <iprt/once.h>
+#endif
+#include <iprt/param.h>
+#include <iprt/string.h>
+
+#include "internal/alignmentchecks.h"
+#include "internal/magics.h"
+#if defined(IPRT_NO_CRT) || defined(IN_RT_STATIC)
+# include "internal/initterm.h"
+#endif
+
+#ifdef RTSTREAM_STANDALONE
+# ifdef _MSC_VER
+#  define IPRT_COMPILER_VCC_WITH_C_INIT_TERM_SECTIONS
+#  include "internal/compiler-vcc.h"
+# endif
+#else
+# include <stdio.h>
+# include <errno.h>
+# if defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)
+#  include <io.h>
+#  include <fcntl.h>
+# endif
+#endif
+#ifdef RT_OS_WINDOWS
+# include <iprt/utf16.h>
+# include <iprt/win/windows.h>
+#elif !defined(RTSTREAM_STANDALONE)
+# include <termios.h>
+# include <unistd.h>
+# include <sys/ioctl.h>
+#endif
+
+#if defined(RT_OS_OS2) && !defined(RTSTREAM_STANDALONE)
+# define _O_TEXT   O_TEXT
+# define _O_BINARY O_BINARY
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+#ifdef RTSTREAM_STANDALONE
+/** The buffer direction. */
+typedef enum RTSTREAMBUFDIR
+{
+    RTSTREAMBUFDIR_NONE = 0,
+    RTSTREAMBUFDIR_READ,
+    RTSTREAMBUFDIR_WRITE
+} RTSTREAMBUFDIR;
+
+/** The buffer style. */
+typedef enum RTSTREAMBUFSTYLE
+{
+    RTSTREAMBUFSTYLE_UNBUFFERED = 0,
+    RTSTREAMBUFSTYLE_LINE,
+    RTSTREAMBUFSTYLE_FULL
+} RTSTREAMBUFSTYLE;
+
+#endif
+
+/**
+ * File stream.
+ */
+typedef struct RTSTREAM
+{
+    /** Magic value used to validate the stream. (RTSTREAM_MAGIC) */
+    uint32_t            u32Magic;
+    /** File stream error. */
+    int32_t volatile    i32Error;
+#ifndef RTSTREAM_STANDALONE
+    /** Pointer to the LIBC file stream. */
+    FILE               *pFile;
+#else
+    /** Indicates which standard handle this is supposed to be.
+     * Set to RTHANDLESTD_INVALID if not one of the tree standard streams. */
+    RTHANDLESTD         enmStdHandle;
+    /** The IPRT handle backing this stream.
+     * This is initialized lazily using enmStdHandle for the three standard
+     * streams. */
+    RTFILE              hFile;
+    /** Buffer. */
+    char               *pchBuf;
+    /** Buffer allocation size. */
+    size_t              cbBufAlloc;
+    /** Offset of the first valid byte in the buffer. */
+    size_t              offBufFirst;
+    /** Offset of the end of valid bytes in the buffer (exclusive). */
+    size_t              offBufEnd;
+    /** The stream buffer direction.   */
+    RTSTREAMBUFDIR      enmBufDir;
+    /** The buffering style (unbuffered, line, full).
+     * @todo replace by RTSTRMBUFMODE.  */
+    RTSTREAMBUFSTYLE    enmBufStyle;
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    /** Bitmap running parallel to each char pchBuf, indicating where a '\\r'
+     * character have been removed during buffer filling.  This is used to implement
+     * RTStrmTell in non-binary mode. */
+    uint32_t           *pbmBuf;
+    /** Indicates that we've got a CR ('\\r') beyond the end of official buffer
+     * and need to check if there is a LF following it.  This member is ignored
+     * in binary mode. */
+    bool                fPendingCr;
+# endif
+#endif
+    /** Stream is using the current process code set. */
+    bool                fCurrentCodeSet;
+    /** Whether the stream was opened in binary mode. */
+    bool                fBinary;
+    /** Whether to recheck the stream mode before writing. */
+    bool                fRecheckMode;
+#if !defined(HAVE_FWRITE_UNLOCKED) || defined(RTSTREAM_STANDALONE)
+    /** Critical section for serializing access to the stream. */
+    PRTCRITSECT         pCritSect;
+#endif
+#ifdef RTSTREAM_STANDALONE
+    /** Entry in g_StreamList (for automatic flushing and closing at
+     * exit/unload). */
+    RTLISTNODE          ListEntry;
+#endif
+} RTSTREAM;
+
+
+/**
+ * State for wrapped output (RTStrmWrappedPrintf, RTStrmWrappedPrintfV).
+ */
+typedef struct RTSTRMWRAPPEDSTATE
+{
+    PRTSTREAM   pStream;            /**< The output stream. */
+    uint32_t    cchWidth;           /**< The line width. */
+    uint32_t    cchLine;            /**< The current line length (valid chars in szLine). */
+    uint32_t    cLines;             /**< Number of lines written. */
+    uint32_t    cchIndent;          /**< The indent (determined from the first line). */
+    int         rcStatus;           /**< The output status. */
+    uint8_t     cchHangingIndent;   /**< Hanging indent (from fFlags). */
+    char        szLine[0x1000+1];   /**< We must buffer output so we can do proper word splitting. */
+} RTSTRMWRAPPEDSTATE;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The standard input stream. */
+static RTSTREAM    g_StdIn =
+{
+    /* .u32Magic = */           RTSTREAM_MAGIC,
+    /* .i32Error = */           0,
+#ifndef RTSTREAM_STANDALONE
+    /* .pFile = */              stdin,
+#else
+    /* .enmStdHandle = */       RTHANDLESTD_INPUT,
+    /* .hFile = */              NIL_RTFILE,
+    /* .pchBuf = */             NULL,
+    /* .cbBufAlloc = */         0,
+    /* .offBufFirst = */        0,
+    /* .offBufEnd = */          0,
+    /* .enmBufDir = */          RTSTREAMBUFDIR_NONE,
+    /* .enmBufStyle = */        RTSTREAMBUFSTYLE_UNBUFFERED,
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    /* .pbmBuf = */             NULL,
+    /* .fPendingCr = */         false,
+# endif
+#endif
+    /* .fCurrentCodeSet = */    true,
+    /* .fBinary = */            false,
+    /* .fRecheckMode = */       true,
+#ifndef HAVE_FWRITE_UNLOCKED
+    /* .pCritSect = */          NULL,
+#endif
+#ifdef RTSTREAM_STANDALONE
+    /* .ListEntry = */          { NULL, NULL },
+#endif
+};
+
+/** The standard error stream. */
+static RTSTREAM    g_StdErr =
+{
+    /* .u32Magic = */           RTSTREAM_MAGIC,
+    /* .i32Error = */           0,
+#ifndef RTSTREAM_STANDALONE
+    /* .pFile = */              stderr,
+#else
+    /* .enmStdHandle = */       RTHANDLESTD_ERROR,
+    /* .hFile = */              NIL_RTFILE,
+    /* .pchBuf = */             NULL,
+    /* .cbBufAlloc = */         0,
+    /* .offBufFirst = */        0,
+    /* .offBufEnd = */          0,
+    /* .enmBufDir = */          RTSTREAMBUFDIR_NONE,
+    /* .enmBufStyle = */        RTSTREAMBUFSTYLE_UNBUFFERED,
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    /* .pbmBuf = */             NULL,
+    /* .fPendingCr = */         false,
+# endif
+#endif
+    /* .fCurrentCodeSet = */    true,
+    /* .fBinary = */            false,
+    /* .fRecheckMode = */       true,
+#ifndef HAVE_FWRITE_UNLOCKED
+    /* .pCritSect = */          NULL,
+#endif
+#ifdef RTSTREAM_STANDALONE
+    /* .ListEntry = */          { NULL, NULL },
+#endif
+};
+
+/** The standard output stream. */
+static RTSTREAM    g_StdOut =
+{
+    /* .u32Magic = */           RTSTREAM_MAGIC,
+    /* .i32Error = */           0,
+#ifndef RTSTREAM_STANDALONE
+    /* .pFile = */              stdout,
+#else
+    /* .enmStdHandle = */       RTHANDLESTD_OUTPUT,
+    /* .hFile = */              NIL_RTFILE,
+    /* .pchBuf = */             NULL,
+    /* .cbBufAlloc = */         0,
+    /* .offBufFirst = */        0,
+    /* .offBufEnd = */          0,
+    /* .enmBufDir = */          RTSTREAMBUFDIR_NONE,
+    /* .enmBufStyle = */        RTSTREAMBUFSTYLE_LINE,
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    /* .pbmBuf = */             NULL,
+    /* .fPendingCr = */         false,
+# endif
+#endif
+    /* .fCurrentCodeSet = */    true,
+    /* .fBinary = */            false,
+    /* .fRecheckMode = */       true,
+#ifndef HAVE_FWRITE_UNLOCKED
+    /* .pCritSect = */          NULL,
+#endif
+#ifdef RTSTREAM_STANDALONE
+    /* .ListEntry = */          { NULL, NULL },
+#endif
+};
+
+/** Pointer to the standard input stream. */
+RTDATADECL(PRTSTREAM)   g_pStdIn  = &g_StdIn;
+
+/** Pointer to the standard output stream. */
+RTDATADECL(PRTSTREAM)   g_pStdErr = &g_StdErr;
+
+/** Pointer to the standard output stream. */
+RTDATADECL(PRTSTREAM)   g_pStdOut = &g_StdOut;
+
+#ifdef RTSTREAM_STANDALONE
+/** Run-once initializer for the stream list (g_StreamList + g_StreamListCritSect). */
+static RTONCE           g_StreamListOnce = RTONCE_INITIALIZER;
+/** List of user created streams (excludes the standard streams). */
+static RTLISTANCHOR     g_StreamList;
+/** Critical section protecting the stream list. */
+static RTCRITSECT       g_StreamListCritSect;
+
+
+/** @callback_method_impl{FNRTONCE}   */
+static DECLCALLBACK(int32_t) rtStrmListInitOnce(void *pvUser)
+{
+    RT_NOREF(pvUser);
+    RTListInit(&g_StreamList);
+    return RTCritSectInit(&g_StreamListCritSect);
+}
+
+#endif
+
+
+#ifndef HAVE_FWRITE_UNLOCKED
+/**
+ * Allocates and acquires the lock for the stream.
+ *
+ * @returns IPRT status code.
+ * @param   pStream     The stream (valid).
+ */
+static int rtStrmAllocLock(PRTSTREAM pStream)
+{
+    Assert(pStream->pCritSect == NULL);
+
+    PRTCRITSECT pCritSect = (PRTCRITSECT)RTMemAlloc(sizeof(*pCritSect));
+    if (!pCritSect)
+        return VERR_NO_MEMORY;
+
+    /* The native stream lock are normally not recursive. */
+    uint32_t fFlags = RTCRITSECT_FLAGS_NO_NESTING;
+# if defined(IPRT_NO_CRT) || defined(IN_RT_STATIC)
+    /* IPRT is often used deliberatly without initialization in no-CRT
+       binaries (for instance VBoxAddInstallNt3x.exe), so in order to avoid
+       asserting in the lock validator we add the bootstrap hack that disable
+       lock validation for the section.
+       Update: Applying this to all builds involving static linking, as it's
+               now going to be used for tests running at compile-time too.  */
+    if (!rtInitIsInitialized())
+        fFlags |= RTCRITSECT_FLAGS_BOOTSTRAP_HACK;
+# endif
+    int rc = RTCritSectInitEx(pCritSect, fFlags, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemSpinMutex");
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTCritSectEnter(pCritSect);
+        if (RT_SUCCESS(rc))
+        {
+            if (RT_LIKELY(ASMAtomicCmpXchgPtr(&pStream->pCritSect, pCritSect, NULL)))
+                return VINF_SUCCESS;
+
+            RTCritSectLeave(pCritSect);
+        }
+        RTCritSectDelete(pCritSect);
+    }
+    RTMemFree(pCritSect);
+
+    /* Handle the lost race case... */
+    pCritSect = ASMAtomicReadPtrT(&pStream->pCritSect, PRTCRITSECT);
+    if (pCritSect)
+        return RTCritSectEnter(pCritSect);
+
+    return rc;
+}
+#endif /* !HAVE_FWRITE_UNLOCKED */
+
+
+/**
+ * Locks the stream.  May have to allocate the lock as well.
+ *
+ * @param   pStream     The stream (valid).
+ */
+DECLINLINE(void) rtStrmLock(PRTSTREAM pStream)
+{
+#ifdef HAVE_FWRITE_UNLOCKED
+    flockfile(pStream->pFile);
+#else
+    if (RT_LIKELY(pStream->pCritSect))
+        RTCritSectEnter(pStream->pCritSect);
+    else
+        rtStrmAllocLock(pStream);
+#endif
+}
+
+
+/**
+ * Unlocks the stream.
+ *
+ * @param   pStream     The stream (valid).
+ */
+DECLINLINE(void) rtStrmUnlock(PRTSTREAM pStream)
+{
+#ifdef HAVE_FWRITE_UNLOCKED
+    funlockfile(pStream->pFile);
+#else
+    if (RT_LIKELY(pStream->pCritSect))
+        RTCritSectLeave(pStream->pCritSect);
+#endif
+}
+
+
+/**
+ * Opens a file stream.
+ *
+ * @returns iprt status code.
+ * @param   pszFilename     Path to the file to open, hFile must be NIL_RTFILE.
+ *                          NULL if a hFile is to be used instead.
+ * @param   hFile           File handle to use when called from
+ *                          RTStrmOpenFileHandle.  pszFilename must be NULL.
+ * @param   pszMode         See RTStrmOpen.
+ * @param   ppStream        Where to store the opened stream.
+ */
+static int rtStrmOpenComon(const char *pszFilename, RTFILE hFile, const char *pszMode, PRTSTREAM *ppStream)
+{
+    /*
+     * Validate input and look for things we care for in the pszMode string.
+     */
+    AssertReturn(pszMode && *pszMode, VERR_INVALID_FLAGS);
+
+    /*
+     * Process the mode string.
+     */
+    char    chMode     = '\0';  /* a|r|w */
+    bool    fPlus      = false; /* + */
+    bool    fBinary    = false; /* b | !t */
+    bool    fExclusive = false; /* x */
+    bool    fNoInherit = false;  /* e (linux, freebsd) | N (win) | E (our for reverse) */
+    const char *psz = pszMode;
+    char        ch;
+    while ((ch = *psz++) != '\0')
+    {
+        switch (ch)
+        {
+            case 'a':
+            case 'r':
+            case 'w':
+                chMode = ch;
+                break;
+            case '+':
+                fPlus = true;
+                break;
+            case 'b':
+                fBinary = true;
+                break;
+            case 't':
+                fBinary = false;
+                break;
+            case 'x':
+                fExclusive = true;
+                break;
+            case 'e':
+            case 'N':
+                fNoInherit = true;
+                break;
+            case 'E':
+                fNoInherit = false;
+                break;
+            default:
+                AssertMsgFailedReturn(("Invalid ch='%c' in pszMode='%s', '<a|r|w>[+][b|t][x][e|N|E]'\n", ch, pszMode),
+                                      VERR_INVALID_FLAGS);
+        }
+    }
+
+    /*
+     * Translate into to RTFILE_O_* flags:
+     */
+    uint64_t fOpen;
+    switch (chMode)
+    {
+        case 'a': fOpen = RTFILE_O_OPEN_CREATE    | RTFILE_O_WRITE | RTFILE_O_APPEND; break;
+        case 'w': fOpen = !fExclusive
+                        ? RTFILE_O_CREATE_REPLACE | RTFILE_O_WRITE
+                        : RTFILE_O_CREATE         | RTFILE_O_WRITE; break;
+        case 'r': fOpen = RTFILE_O_OPEN           | RTFILE_O_READ; break;
+        default:  AssertMsgFailedReturn(("No main mode (a|r|w) specified in '%s'!\n", pszMode), VERR_INVALID_FLAGS);
+    }
+    AssertMsgReturn(!fExclusive || chMode == 'w', ("the 'x' flag is only allowed with 'w'! (%s)\n", pszMode),
+                    VERR_INVALID_FLAGS);
+    if (fExclusive)
+        fOpen |= RTFILE_O_READ | RTFILE_O_WRITE;
+    if (fPlus)
+        fOpen |= RTFILE_O_READ | RTFILE_O_WRITE;
+    if (!fNoInherit)
+        fOpen |= RTFILE_O_INHERIT;
+    fOpen |= RTFILE_O_DENY_NONE;
+    fOpen |= 0666 << RTFILE_O_CREATE_MODE_SHIFT;
+
+#ifndef RTSTREAM_STANDALONE
+    /*
+     * Normalize mode for fdopen.
+     */
+    char szNormalizedMode[8];
+    szNormalizedMode[0] = chMode;
+    size_t off = 1;
+    if (fPlus)
+        szNormalizedMode[off++] = '+';
+    if (fBinary)
+        szNormalizedMode[off++] = 'b';
+    szNormalizedMode[off] = '\0';
+#endif
+
+#ifdef RTSTREAM_STANDALONE
+    /*
+     * Make the the stream list is initialized before we allocate anything.
+     */
+    int rc2 = RTOnce(&g_StreamListOnce, rtStrmListInitOnce, NULL);
+    AssertRCReturn(rc2, rc2);
+#endif
+
+    /*
+     * Allocate the stream handle and try open it.
+     */
+    int rc = VERR_NO_MEMORY;
+    PRTSTREAM pStream = (PRTSTREAM)RTMemAllocZ(sizeof(*pStream));
+    if (pStream)
+    {
+        pStream->u32Magic           = RTSTREAM_MAGIC;
+#ifdef RTSTREAM_STANDALONE
+        pStream->enmStdHandle       = RTHANDLESTD_INVALID;
+        pStream->hFile              = NIL_RTFILE;
+        pStream->pchBuf             = NULL;
+        pStream->cbBufAlloc         = 0;
+        pStream->offBufFirst        = 0;
+        pStream->offBufEnd          = 0;
+        pStream->enmBufDir          = RTSTREAMBUFDIR_NONE;
+        pStream->enmBufStyle        = RTSTREAMBUFSTYLE_FULL;
+# ifdef RTSTREAM_WITH_TEXT_MODE
+        pStream->pbmBuf             = NULL;
+        pStream->fPendingCr         = false,
+# endif
+#endif
+        pStream->i32Error           = VINF_SUCCESS;
+        pStream->fCurrentCodeSet    = false;
+        pStream->fBinary            = fBinary;
+        pStream->fRecheckMode       = false;
+#ifndef HAVE_FWRITE_UNLOCKED
+        pStream->pCritSect          = NULL;
+#endif
+        RTFILEACTION enmActionTaken = RTFILEACTION_INVALID;
+        if (pszFilename)
+            rc = RTFileOpenEx(pszFilename, fOpen, &hFile, &enmActionTaken);
+        else
+            rc = VINF_SUCCESS;
+        if (RT_SUCCESS(rc))
+        {
+#ifndef RTSTREAM_STANDALONE
+# ifndef _MSC_VER
+            int fd = (int)RTFileToNative(hFile);
+# else
+            int fd = _open_osfhandle(RTFileToNative(hFile),
+                                       (fPlus ? _O_RDWR : chMode == 'r' ? _O_RDONLY : _O_WRONLY)
+                                     | (chMode == 'a' ? _O_APPEND : 0)
+                                     | (fBinary ? _O_BINARY : _O_TEXT)
+                                     | (fNoInherit ? _O_NOINHERIT : 0));
+# endif
+            if (fd >= 0)
+            {
+                pStream->pFile = fdopen(fd, szNormalizedMode);
+                if (pStream->pFile)
+#endif
+                {
+#ifdef RTSTREAM_STANDALONE
+                    pStream->hFile = hFile;
+
+                    /* We keep a list of these for cleanup purposes. */
+                    RTCritSectEnter(&g_StreamListCritSect);
+                    RTListAppend(&g_StreamList, &pStream->ListEntry);
+                    RTCritSectLeave(&g_StreamListCritSect);
+#endif
+                    *ppStream = pStream;
+                    return VINF_SUCCESS;
+                }
+
+                /*
+                 * This better not happen too often as in 'w' mode we might've
+                 * truncated a file, and in 'w' and 'a' modes there is a chance
+                 * that we'll race other access to the file when deleting it.
+                 */
+#ifndef RTSTREAM_STANDALONE
+                rc = RTErrConvertFromErrno(errno);
+# ifdef _MSC_VER
+                close(fd);
+                hFile = NIL_RTFILE;
+                /** @todo we're in trouble here when called from RTStrmOpenFileHandle!   */
+# endif
+            }
+            else
+            {
+# ifdef _MSC_VER
+                rc = RTErrConvertFromErrno(errno);
+# else
+                AssertFailedStmt(rc = VERR_INVALID_HANDLE);
+# endif
+            }
+            if (pszFilename)
+            {
+                RTFileClose(hFile);
+                if (enmActionTaken == RTFILEACTION_CREATED)
+                    RTFileDelete(pszFilename);
+            }
+#endif
+        }
+        RTMemFree(pStream);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmOpen(const char *pszFilename, const char *pszMode, PRTSTREAM *ppStream)
+{
+    *ppStream = NULL;
+    AssertReturn(pszFilename, VERR_INVALID_PARAMETER);
+    return rtStrmOpenComon(pszFilename, NIL_RTFILE, pszMode, ppStream);
+}
+
+
+RTR3DECL(int) RTStrmOpenFV(const char *pszMode, PRTSTREAM *ppStream, const char *pszFilenameFmt, va_list args)
+{
+    int     rc;
+    char    szFilename[RTPATH_MAX];
+    size_t  cch = RTStrPrintfV(szFilename, sizeof(szFilename), pszFilenameFmt, args);
+    if (cch < sizeof(szFilename))
+        rc = RTStrmOpen(szFilename, pszMode, ppStream);
+    else
+    {
+        AssertMsgFailed(("The filename is too long cch=%d\n", cch));
+        rc = VERR_FILENAME_TOO_LONG;
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmOpenF(const char *pszMode, PRTSTREAM *ppStream, const char *pszFilenameFmt, ...)
+{
+    va_list args;
+    va_start(args, pszFilenameFmt);
+    int rc = RTStrmOpenFV(pszMode, ppStream, pszFilenameFmt, args);
+    va_end(args);
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmOpenFileHandle(RTFILE hFile, const char *pszMode, uint32_t fFlags, PRTSTREAM *ppStream)
+{
+    *ppStream = NULL;
+    AssertReturn(RTFileIsValid(hFile), VERR_INVALID_HANDLE);
+    AssertReturn(fFlags == 0, VERR_INVALID_FLAGS);
+    return rtStrmOpenComon(NULL, hFile, pszMode, ppStream);
+}
+
+
+RTR3DECL(int) RTStrmClose(PRTSTREAM pStream)
+{
+    /*
+     * Validate input.
+     */
+    if (!pStream)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pStream, VERR_INVALID_POINTER);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_MAGIC);
+
+    /* We don't implement closing any of the standard handles at present. */
+    AssertReturn(pStream != &g_StdIn, VERR_NOT_SUPPORTED);
+    AssertReturn(pStream != &g_StdOut, VERR_NOT_SUPPORTED);
+    AssertReturn(pStream != &g_StdErr, VERR_NOT_SUPPORTED);
+
+    /*
+     * Invalidate the stream and destroy the critical section first.
+     */
+#ifdef RTSTREAM_STANDALONE
+    RTCritSectEnter(&g_StreamListCritSect);
+    RTListNodeRemove(&pStream->ListEntry);
+    RTCritSectLeave(&g_StreamListCritSect);
+#endif
+    pStream->u32Magic = 0xdeaddead;
+#ifndef HAVE_FWRITE_UNLOCKED
+    if (pStream->pCritSect)
+    {
+        RTCritSectEnter(pStream->pCritSect);
+        RTCritSectLeave(pStream->pCritSect);
+        RTCritSectDelete(pStream->pCritSect);
+        RTMemFree(pStream->pCritSect);
+        pStream->pCritSect = NULL;
+    }
+#endif
+
+    /*
+     * Flush and close the underlying file.
+     */
+#ifdef RTSTREAM_STANDALONE
+    int const rc1 = RTStrmFlush(pStream);
+    AssertRC(rc1);
+    int const rc2 = RTFileClose(pStream->hFile);
+    AssertRC(rc2);
+    int const rc = RT_SUCCESS(rc1) ? rc2 : rc1;
+#else
+    int const rc = !fclose(pStream->pFile) ? VINF_SUCCESS : RTErrConvertFromErrno(errno);
+#endif
+
+    /*
+     * Destroy the stream.
+     */
+#ifdef RTSTREAM_STANDALONE
+    pStream->hFile          = NIL_RTFILE;
+    RTMemFree(pStream->pchBuf);
+    pStream->pchBuf         = NULL;
+    pStream->cbBufAlloc     = 0;
+    pStream->offBufFirst    = 0;
+    pStream->offBufEnd      = 0;
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    RTMemFree(pStream->pbmBuf);
+    pStream->pbmBuf         = NULL;
+# endif
+#else
+    pStream->pFile          = NULL;
+#endif
+    RTMemFree(pStream);
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmError(PRTSTREAM pStream)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_POINTER);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_MAGIC);
+    return pStream->i32Error;
+}
+
+
+RTR3DECL(int) RTStrmClearError(PRTSTREAM pStream)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_POINTER);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_MAGIC);
+
+#ifndef RTSTREAM_STANDALONE
+    clearerr(pStream->pFile);
+#endif
+    ASMAtomicWriteS32(&pStream->i32Error, VINF_SUCCESS);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTStrmSetMode(PRTSTREAM pStream, int fBinary, int fCurrentCodeSet)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn((unsigned)(fBinary + 1) <= 2, VERR_INVALID_PARAMETER);
+    AssertReturn((unsigned)(fCurrentCodeSet + 1) <= 2, VERR_INVALID_PARAMETER);
+
+    rtStrmLock(pStream);
+
+    if (fBinary != -1)
+    {
+        pStream->fBinary      = RT_BOOL(fBinary);
+        pStream->fRecheckMode = true;
+    }
+
+    if (fCurrentCodeSet != -1)
+        pStream->fCurrentCodeSet = RT_BOOL(fCurrentCodeSet);
+
+    rtStrmUnlock(pStream);
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTStrmSetBufferingMode(PRTSTREAM pStream, RTSTRMBUFMODE enmMode)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(enmMode > RTSTRMBUFMODE_INVALID && enmMode < RTSTRMBUFMODE_END, VERR_INVALID_PARAMETER);
+
+#ifndef RTSTREAM_STANDALONE
+    int iCrtMode = enmMode == RTSTRMBUFMODE_FULL ? _IOFBF : enmMode == RTSTRMBUFMODE_LINE ? _IOLBF : _IONBF;
+    int rc = setvbuf(pStream->pFile, NULL, iCrtMode, 0);
+    if (rc >= 0)
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+
+#else
+    rtStrmLock(pStream);
+    pStream->enmBufStyle = enmMode == RTSTRMBUFMODE_FULL ? RTSTREAMBUFSTYLE_FULL
+                         : enmMode == RTSTRMBUFMODE_LINE ? RTSTREAMBUFSTYLE_LINE : RTSTREAMBUFSTYLE_UNBUFFERED;
+    rtStrmUnlock(pStream);
+    return VINF_SUCCESS;
+#endif
+}
+
+
+#ifdef RTSTREAM_STANDALONE
+
+/**
+ * Deals with NIL_RTFILE in rtStrmGetFile.
+ */
+DECL_NO_INLINE(static, RTFILE) rtStrmGetFileNil(PRTSTREAM pStream)
+{
+# ifdef RT_OS_WINDOWS
+    DWORD dwStdHandle;
+    switch (pStream->enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:     dwStdHandle = STD_INPUT_HANDLE; break;
+        case RTHANDLESTD_OUTPUT:    dwStdHandle = STD_OUTPUT_HANDLE; break;
+        case RTHANDLESTD_ERROR:     dwStdHandle = STD_ERROR_HANDLE; break;
+        default:                    return NIL_RTFILE;
+    }
+    HANDLE hHandle = GetStdHandle(dwStdHandle);
+    if (hHandle != INVALID_HANDLE_VALUE && hHandle != NULL)
+    {
+        int rc = RTFileFromNative(&pStream->hFile, (uintptr_t)hHandle);
+        if (RT_SUCCESS(rc))
+        {
+            /* Switch to full buffering if not a console handle. */
+            DWORD dwMode;
+            if (!GetConsoleMode(hHandle, &dwMode))
+                pStream->enmBufStyle = RTSTREAMBUFSTYLE_FULL;
+
+            return pStream->hFile;
+        }
+    }
+
+# else
+    uintptr_t uNative;
+    switch (pStream->enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:     uNative = RTFILE_NATIVE_STDIN; break;
+        case RTHANDLESTD_OUTPUT:    uNative = RTFILE_NATIVE_STDOUT; break;
+        case RTHANDLESTD_ERROR:     uNative = RTFILE_NATIVE_STDERR; break;
+        default:                    return NIL_RTFILE;
+    }
+    int rc = RTFileFromNative(&pStream->hFile, uNative);
+    if (RT_SUCCESS(rc))
+    {
+        /* Switch to full buffering if not a console handle. */
+        if (!isatty((int)uNative))
+            pStream->enmBufStyle = RTSTREAMBUFDIR_FULL;
+
+        return pStream->hFile;
+    }
+
+# endif
+    return NIL_RTFILE;
+}
+
+
+/**
+ * For lazily resolving handles for the standard streams.
+ */
+DECLINLINE(RTFILE) rtStrmGetFile(PRTSTREAM pStream)
+{
+    RTFILE hFile = pStream->hFile;
+    if (hFile != NIL_RTFILE)
+        return hFile;
+    return rtStrmGetFileNil(pStream);
+}
+
+
+RTR3DECL(int) RTStrmQueryFileHandle(PRTSTREAM pStream, PRTFILE phFile)
+{
+    AssertPtrReturn(phFile, VERR_INVALID_POINTER);
+    *phFile = NIL_RTFILE;
+    AssertPtrReturn(pStream, VERR_INVALID_POINTER);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_MAGIC);
+
+    rtStrmLock(pStream);
+    RTFILE hFile = rtStrmGetFile(pStream);
+    rtStrmUnlock(pStream);
+    if (hFile != NIL_RTFILE)
+    {
+        *phFile = hFile;
+        return VINF_SUCCESS;
+    }
+    return VERR_NOT_AVAILABLE;
+}
+
+#endif /* RTSTREAM_STANDALONE */
+
+
+/**
+ * Wrapper around isatty, assumes caller takes care of stream locking/whatever
+ * is needed.
+ */
+DECLINLINE(bool) rtStrmIsTerminal(PRTSTREAM pStream)
+{
+#ifdef RTSTREAM_STANDALONE
+    RTFILE hFile = rtStrmGetFile(pStream);
+    if (hFile != NIL_RTFILE)
+    {
+        HANDLE hNative = (HANDLE)RTFileToNative(hFile);
+        DWORD dwType = GetFileType(hNative);
+        if (dwType == FILE_TYPE_CHAR)
+        {
+            DWORD dwMode;
+            if (GetConsoleMode(hNative, &dwMode))
+                return true;
+        }
+    }
+    return false;
+
+#else
+    if (pStream->pFile)
+    {
+        int fh = fileno(pStream->pFile);
+        if (isatty(fh) != 0)
+        {
+# ifdef RT_OS_WINDOWS
+            DWORD  dwMode;
+            HANDLE hCon = (HANDLE)_get_osfhandle(fh);
+            if (GetConsoleMode(hCon, &dwMode))
+                return true;
+# else
+            return true;
+# endif
+        }
+    }
+    return false;
+#endif
+}
+
+
+static int rtStrmInputGetEchoCharsNative(uintptr_t hNative, bool *pfEchoChars)
+{
+#ifdef RT_OS_WINDOWS
+    DWORD dwMode;
+    if (GetConsoleMode((HANDLE)hNative, &dwMode))
+        *pfEchoChars = RT_BOOL(dwMode & ENABLE_ECHO_INPUT);
+    else
+    {
+        DWORD dwErr = GetLastError();
+        if (dwErr == ERROR_INVALID_HANDLE)
+            return GetFileType((HANDLE)hNative) != FILE_TYPE_UNKNOWN ? VERR_INVALID_FUNCTION : VERR_INVALID_HANDLE;
+        return RTErrConvertFromWin32(dwErr);
+    }
+#else
+    struct termios Termios;
+    int rcPosix = tcgetattr((int)hNative, &Termios);
+    if (!rcPosix)
+        *pfEchoChars = RT_BOOL(Termios.c_lflag & ECHO);
+    else
+        return errno == ENOTTY ? VERR_INVALID_FUNCTION :  RTErrConvertFromErrno(errno);
+#endif
+    return VINF_SUCCESS;
+}
+
+
+
+RTR3DECL(int) RTStrmInputGetEchoChars(PRTSTREAM pStream, bool *pfEchoChars)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfEchoChars, VERR_INVALID_POINTER);
+
+#ifdef RTSTREAM_STANDALONE
+    return rtStrmInputGetEchoCharsNative(RTFileToNative(pStream->hFile), pfEchoChars);
+#else
+    int rc;
+    int fh = fileno(pStream->pFile);
+    if (isatty(fh))
+    {
+# ifdef RT_OS_WINDOWS
+        rc = rtStrmInputGetEchoCharsNative(_get_osfhandle(fh), pfEchoChars);
+# else
+        rc = rtStrmInputGetEchoCharsNative(fh, pfEchoChars);
+# endif
+    }
+    else
+        rc = VERR_INVALID_FUNCTION;
+    return rc;
+#endif
+}
+
+
+static int rtStrmInputSetEchoCharsNative(uintptr_t hNative, bool fEchoChars)
+{
+    int rc;
+#ifdef RT_OS_WINDOWS
+    DWORD dwMode;
+    if (GetConsoleMode((HANDLE)hNative, &dwMode))
+    {
+        if (fEchoChars)
+            dwMode |= ENABLE_ECHO_INPUT;
+        else
+            dwMode &= ~ENABLE_ECHO_INPUT;
+        if (SetConsoleMode((HANDLE)hNative, dwMode))
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        DWORD dwErr = GetLastError();
+        if (dwErr == ERROR_INVALID_HANDLE)
+            return GetFileType((HANDLE)hNative) != FILE_TYPE_UNKNOWN ? VERR_INVALID_FUNCTION : VERR_INVALID_HANDLE;
+        return RTErrConvertFromWin32(dwErr);
+    }
+#else
+    struct termios Termios;
+    int rcPosix = tcgetattr((int)hNative, &Termios);
+    if (!rcPosix)
+    {
+        if (fEchoChars)
+            Termios.c_lflag |= ECHO;
+        else
+            Termios.c_lflag &= ~ECHO;
+
+        rcPosix = tcsetattr((int)hNative, TCSAFLUSH, &Termios);
+        if (rcPosix == 0)
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromErrno(errno);
+    }
+    else
+        rc = errno == ENOTTY ? VERR_INVALID_FUNCTION : RTErrConvertFromErrno(errno);
+#endif
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmInputSetEchoChars(PRTSTREAM pStream, bool fEchoChars)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSTREAM_STANDALONE
+    return rtStrmInputSetEchoCharsNative(RTFileToNative(pStream->hFile), fEchoChars);
+#else
+    int rc;
+    int fh = fileno(pStream->pFile);
+    if (isatty(fh))
+    {
+# ifdef RT_OS_WINDOWS
+        rc = rtStrmInputSetEchoCharsNative(_get_osfhandle(fh), fEchoChars);
+# else
+        rc = rtStrmInputSetEchoCharsNative(fh, fEchoChars);
+# endif
+    }
+    else
+        rc = VERR_INVALID_FUNCTION;
+    return rc;
+#endif
+}
+
+
+RTR3DECL(bool) RTStrmIsTerminal(PRTSTREAM pStream)
+{
+    AssertPtrReturn(pStream, false);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, false);
+
+    return rtStrmIsTerminal(pStream);
+}
+
+
+RTR3DECL(int) RTStrmQueryTerminalWidth(PRTSTREAM pStream, uint32_t *pcchWidth)
+{
+    AssertPtrReturn(pcchWidth, VERR_INVALID_HANDLE);
+    *pcchWidth = 80;
+
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+
+    if (rtStrmIsTerminal(pStream))
+    {
+#ifdef RT_OS_WINDOWS
+# ifdef RTSTREAM_STANDALONE
+        HANDLE hCon = (HANDLE)RTFileToNative(pStream->hFile);
+# else
+        HANDLE hCon = (HANDLE)_get_osfhandle(fileno(pStream->pFile));
+# endif
+        CONSOLE_SCREEN_BUFFER_INFO Info;
+        RT_ZERO(Info);
+        if (GetConsoleScreenBufferInfo(hCon, &Info))
+        {
+            *pcchWidth = Info.dwSize.X ? Info.dwSize.X : 80;
+            return VINF_SUCCESS;
+        }
+        return RTErrConvertFromWin32(GetLastError());
+
+#elif defined(RT_OS_OS2) && !defined(TIOCGWINSZ) /* only OS/2 should currently miss this */
+        return VINF_SUCCESS; /* just pretend for now. */
+
+#else
+        struct winsize Info;
+        RT_ZERO(Info);
+        int rc = ioctl(fileno(pStream->pFile), TIOCGWINSZ, &Info);
+        if (rc >= 0)
+        {
+            *pcchWidth = Info.ws_col ? Info.ws_col : 80;
+            return VINF_SUCCESS;
+        }
+        return RTErrConvertFromErrno(errno);
+#endif
+    }
+    return VERR_INVALID_FUNCTION;
+}
+
+
+#ifdef RTSTREAM_STANDALONE
+
+DECLINLINE(void) rtStrmBufInvalidate(PRTSTREAM pStream)
+{
+    pStream->enmBufDir   = RTSTREAMBUFDIR_NONE;
+    pStream->offBufEnd   = 0;
+    pStream->offBufFirst = 0;
+}
+
+
+static int rtStrmBufFlushWrite(PRTSTREAM pStream, size_t cbToFlush)
+{
+    Assert(cbToFlush <= pStream->offBufEnd - pStream->offBufFirst);
+
+    RTFILE const hFile = rtStrmGetFile(pStream);
+    if (hFile != NIL_RTFILE)
+    {
+        /** @todo do nonblocking & incomplete writes?   */
+        size_t offBufFirst = pStream->offBufFirst;
+        int rc = RTFileWrite(hFile, &pStream->pchBuf[offBufFirst], cbToFlush, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            offBufFirst += cbToFlush;
+            if (offBufFirst >= pStream->offBufEnd)
+                pStream->offBufEnd = 0;
+            else
+            {
+                /* Shift up the remaining content so the next write can take full
+                   advantage of the buffer size. */
+                size_t cbLeft = pStream->offBufEnd - offBufFirst;
+                memmove(pStream->pchBuf, &pStream->pchBuf[offBufFirst], cbLeft);
+                pStream->offBufEnd = cbLeft;
+            }
+            pStream->offBufFirst = 0;
+            return VINF_SUCCESS;
+        }
+        return rc;
+    }
+    return VERR_INVALID_HANDLE;
+}
+
+
+static int rtStrmBufFlushWriteMaybe(PRTSTREAM pStream, bool fInvalidate)
+{
+    if (pStream->enmBufDir == RTSTREAMBUFDIR_WRITE)
+    {
+        size_t cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+        if (cbInBuffer > 0)
+        {
+            int rc = rtStrmBufFlushWrite(pStream, cbInBuffer);
+            if (fInvalidate)
+                pStream->enmBufDir = RTSTREAMBUFDIR_NONE;
+            return rc;
+        }
+    }
+    if (fInvalidate)
+        rtStrmBufInvalidate(pStream);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Worker for rtStrmBufCheckErrorAndSwitchToReadMode and
+ * rtStrmBufCheckErrorAndSwitchToWriteMode that allocates a buffer.
+ *
+ * Only updates cbBufAlloc and pchBuf, callers deals with error fallout.
+ */
+static int rtStrmBufAlloc(PRTSTREAM pStream)
+{
+    size_t cbBuf = pStream->enmBufStyle == RTSTREAMBUFSTYLE_FULL ? _64K : _16K;
+    do
+    {
+        pStream->pchBuf = (char *)RTMemAllocZ(cbBuf);
+        if (RT_LIKELY(pStream->pchBuf))
+        {
+# ifdef RTSTREAM_WITH_TEXT_MODE
+            Assert(RT_ALIGN_Z(cbBuf, 64 / 8) == cbBuf);
+            pStream->pbmBuf = (uint32_t *)RTMemAllocZ(cbBuf / 8);
+            if (RT_LIKELY(pStream->pbmBuf))
+# endif
+            {
+                pStream->cbBufAlloc = cbBuf;
+                return VINF_SUCCESS;
+            }
+# ifdef RTSTREAM_WITH_TEXT_MODE
+            RTMemFree(pStream->pchBuf);
+            pStream->pchBuf = NULL;
+# endif
+        }
+        cbBuf /= 2;
+    } while (cbBuf >= 256);
+    return VERR_NO_MEMORY;
+}
+
+
+/**
+ * Checks the stream error status, flushed any pending writes, ensures there is
+ * a buffer allocated and switches the stream to the read direction.
+ *
+ * @returns IPRT status code (same as i32Error).
+ * @param   pStream             The stream.
+ */
+static int rtStrmBufCheckErrorAndSwitchToReadMode(PRTSTREAM pStream)
+{
+    int rc = pStream->i32Error;
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * We're very likely already in read mode and can return without doing
+         * anything here.
+         */
+        if (pStream->enmBufDir == RTSTREAMBUFDIR_READ)
+            return VINF_SUCCESS;
+
+        /*
+         * Flush any pending writes before switching the buffer to read:
+         */
+        rc = rtStrmBufFlushWriteMaybe(pStream, false /*fInvalidate*/);
+        if (RT_SUCCESS(rc))
+        {
+            pStream->enmBufDir   = RTSTREAMBUFDIR_READ;
+            pStream->offBufEnd   = 0;
+            pStream->offBufFirst = 0;
+            pStream->fPendingCr  = false;
+
+            /*
+             * Read direction implies a buffer, so make sure we've got one and
+             * change to NONE direction if allocating one fails.
+             */
+            if (pStream->pchBuf)
+            {
+                Assert(pStream->cbBufAlloc >= 256);
+                return VINF_SUCCESS;
+            }
+
+            rc = rtStrmBufAlloc(pStream);
+            if (RT_SUCCESS(rc))
+                return VINF_SUCCESS;
+
+            pStream->enmBufDir = RTSTREAMBUFDIR_NONE;
+        }
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+    }
+    return rc;
+}
+
+
+/**
+ * Checks the stream error status, ensures there is a buffer allocated and
+ * switches the stream to the write direction.
+ *
+ * @returns IPRT status code (same as i32Error).
+ * @param   pStream             The stream.
+ */
+static int rtStrmBufCheckErrorAndSwitchToWriteMode(PRTSTREAM pStream)
+{
+    int rc = pStream->i32Error;
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * We're very likely already in write mode and can return without doing
+         * anything here.
+         */
+        if (pStream->enmBufDir == RTSTREAMBUFDIR_WRITE)
+            return VINF_SUCCESS;
+
+        /*
+         * A read buffer does not need any flushing, so we just have to make
+         * sure there is a buffer present before switching to the write direction.
+         */
+        pStream->enmBufDir   = RTSTREAMBUFDIR_WRITE;
+        pStream->offBufEnd   = 0;
+        pStream->offBufFirst = 0;
+        if (pStream->pchBuf)
+        {
+            Assert(pStream->cbBufAlloc >= 256);
+            return VINF_SUCCESS;
+        }
+
+        rc = rtStrmBufAlloc(pStream);
+        if (RT_SUCCESS(rc))
+            return VINF_SUCCESS;
+
+        pStream->enmBufDir = RTSTREAMBUFDIR_NONE;
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+    }
+    return rc;
+}
+
+
+/**
+ * Reads more bytes into the buffer.
+ *
+ * @returns IPRT status code (same as i32Error).
+ * @param   pStream             The stream.
+ */
+static int rtStrmBufFill(PRTSTREAM pStream)
+{
+    /*
+     * Check preconditions
+     */
+    Assert(pStream->i32Error    == VINF_SUCCESS);
+    Assert(pStream->enmBufDir   == RTSTREAMBUFDIR_READ);
+    AssertPtr(pStream->pchBuf);
+    Assert(pStream->cbBufAlloc  >= 256);
+    Assert(RT_ALIGN_Z(pStream->cbBufAlloc, 64) == pStream->cbBufAlloc);
+    Assert(pStream->offBufFirst <= pStream->cbBufAlloc);
+    Assert(pStream->offBufEnd   <= pStream->cbBufAlloc);
+    Assert(pStream->offBufFirst <= pStream->offBufEnd);
+# ifdef RTSTREAM_WITH_TEXT_MODE
+    AssertPtr(pStream->pbmBuf);
+# endif
+    /*
+     * If there is data in the buffer, move it up to the start.
+     */
+    size_t cbInBuffer;
+    if (!pStream->offBufFirst)
+        cbInBuffer = pStream->offBufEnd;
+    else
+    {
+        cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+        if (cbInBuffer)
+        {
+            memmove(pStream->pchBuf, &pStream->pchBuf[pStream->offBufFirst], cbInBuffer);
+# ifdef RTSTREAM_WITH_TEXT_MODE
+            if (!pStream->fBinary) /** @todo this isn't very efficient, must be a better way of shifting a bitmap. */
+                for (size_t off = 0; off < pStream->offBufFirst; off++)
+                    if (ASMBitTest(pStream->pbmBuf, (int32_t)off))
+                        ASMBitSet(pStream->pbmBuf, (int32_t)off);
+                    else
+                        ASMBitClear(pStream->pbmBuf, (int32_t)off);
+# endif
+        }
+        pStream->offBufFirst = 0;
+        pStream->offBufEnd   = cbInBuffer;
+    }
+
+    /*
+     * Add pending CR to the buffer.
+     */
+    size_t const offCrLfConvStart = cbInBuffer;
+    Assert(cbInBuffer + 2 <= pStream->cbBufAlloc);
+    if (!pStream->fPendingCr || pStream->fBinary)
+    { /* likely */ }
+    else
+    {
+        pStream->pchBuf[cbInBuffer] = '\r';
+        pStream->fPendingCr         = false;
+        pStream->offBufEnd          = ++cbInBuffer;
+    }
+
+    /*
+     * Read data till the buffer is full.
+     */
+    int          rc     = VERR_INVALID_HANDLE;
+    RTFILE const hFile  = rtStrmGetFile(pStream);
+    if (hFile != NIL_RTFILE)
+    {
+        size_t   cbRead = 0;
+        rc = RTFileRead(hFile, &pStream->pchBuf[cbInBuffer], pStream->cbBufAlloc - cbInBuffer, &cbRead);
+        if (RT_SUCCESS(rc))
+        {
+            cbInBuffer        += cbRead;
+            pStream->offBufEnd = cbInBuffer;
+
+            if (cbInBuffer != 0)
+            {
+# ifdef RTSTREAM_WITH_TEXT_MODE
+            if (pStream->fBinary)
+# endif
+                return VINF_SUCCESS;
+            }
+            else
+            {
+                /** @todo this shouldn't be sticky, should it? */
+                ASMAtomicWriteS32(&pStream->i32Error, VERR_EOF);
+                return VERR_EOF;
+            }
+
+# ifdef RTSTREAM_WITH_TEXT_MODE
+            /*
+             * Do CRLF -> LF conversion in the buffer.
+             */
+            ASMBitClearRange(pStream->pbmBuf, offCrLfConvStart, RT_ALIGN_Z(cbInBuffer, 64));
+            char  *pchCur = &pStream->pchBuf[offCrLfConvStart];
+            size_t cbLeft = cbInBuffer - offCrLfConvStart;
+            while (cbLeft > 0)
+            {
+                Assert(&pchCur[cbLeft] == &pStream->pchBuf[pStream->offBufEnd]);
+                char *pchCr = (char *)memchr(pchCur, '\r', cbLeft);
+                if (pchCr)
+                {
+                    size_t offCur = (size_t)(pchCr - pchCur);
+                    if (offCur + 1 < cbLeft)
+                    {
+                        if (pchCr[1] == '\n')
+                        {
+                            /* Found one '\r\n' sequence. Look for more before shifting the buffer content. */
+                            cbLeft -= offCur;
+                            pchCur  = pchCr;
+
+                            do
+                            {
+                                ASMBitSet(pStream->pbmBuf, (int32_t)(pchCur - pStream->pchBuf));
+                                *pchCur++  = '\n'; /* dst */
+                                cbLeft    -= 2;
+                                pchCr     += 2;    /* src */
+                            } while  (cbLeft >= 2 && pchCr[0] == '\r' && pchCr[1] == '\n');
+
+                            memmove(&pchCur, pchCr, cbLeft);
+                        }
+                        else
+                        {
+                            cbLeft -= offCur + 1;
+                            pchCur  = pchCr  + 1;
+                        }
+                    }
+                    else
+                    {
+                        Assert(pchCr == &pStream->pchBuf[pStream->offBufEnd - 1]);
+                        pStream->fPendingCr = true;
+                        pStream->offBufEnd  = --cbInBuffer;
+                        break;
+                    }
+                }
+                else
+                    break;
+            }
+
+            return VINF_SUCCESS;
+# endif
+        }
+    }
+
+    /*
+     * If there is data in the buffer, don't raise the error till it has all
+     * been consumed, ASSUMING that another fill call will follow and that the
+     * error condition will reoccur then.
+     *
+     * Note! We may currently end up not converting a CRLF pair, if it's
+     *       split over a temporary EOF condition, since we forces the caller
+     *       to read the CR before requesting more data.  However, it's not a
+     *       very likely scenario, so we'll just leave it like that for now.
+     */
+    if (cbInBuffer)
+        return VINF_SUCCESS;
+    ASMAtomicWriteS32(&pStream->i32Error, rc);
+    return rc;
+}
+
+
+/**
+ * Copies @a cbSrc bytes from @a pvSrc and into the buffer, flushing as needed
+ * to make space available.
+ *
+ *
+ * @returns IPRT status code (errors not assigned to i32Error).
+ * @param   pStream             The stream.
+ * @param   pvSrc               The source buffer.
+ * @param   cbSrc               Number of bytes to copy from @a pvSrc.
+ * @param   pcbTotal            A total counter to update with what was copied.
+ */
+static int rtStrmBufCopyTo(PRTSTREAM pStream, const void *pvSrc, size_t cbSrc, size_t *pcbTotal)
+{
+    Assert(cbSrc > 0);
+    for (;;)
+    {
+        size_t cbToCopy = RT_MIN(pStream->cbBufAlloc - pStream->offBufEnd, cbSrc);
+        if (cbToCopy)
+        {
+            memcpy(&pStream->pchBuf[pStream->offBufEnd], pvSrc, cbToCopy);
+            pStream->offBufEnd += cbToCopy;
+            pvSrc               = (const char *)pvSrc + cbToCopy;
+            *pcbTotal          += cbToCopy;
+            cbSrc              -= cbToCopy;
+            if (!cbSrc)
+                break;
+        }
+
+        int rc = rtStrmBufFlushWrite(pStream, pStream->offBufEnd - pStream->offBufFirst);
+        if (RT_FAILURE(rc))
+            return rc;
+    }
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Worker for rtStrmFlushAndCloseAll and rtStrmFlushAndClose.
+ */
+static RTFILE rtStrmFlushAndCleanup(PRTSTREAM pStream)
+{
+    if (pStream->pchBuf)
+    {
+        if (   pStream->enmBufDir == RTSTREAMBUFDIR_WRITE
+            && pStream->offBufFirst < pStream->offBufEnd
+            && RT_SUCCESS(pStream->i32Error) )
+            rtStrmBufFlushWrite(pStream, pStream->offBufEnd - pStream->offBufFirst);
+        RTMemFree(pStream->pchBuf);
+        pStream->pchBuf      = NULL;
+        pStream->offBufFirst = 0;
+        pStream->offBufEnd   = 0;
+# ifdef RTSTREAM_WITH_TEXT_MODE
+        RTMemFree(pStream->pbmBuf);
+        pStream->pbmBuf = NULL;
+# endif
+    }
+
+    PRTCRITSECT pCritSect = pStream->pCritSect;
+    if (pCritSect)
+    {
+        pStream->pCritSect = NULL;
+        RTCritSectDelete(pCritSect);
+        RTMemFree(pCritSect);
+    }
+
+    RTFILE hFile = pStream->hFile;
+    pStream->hFile = NIL_RTFILE;
+    return hFile;
+}
+
+
+/**
+ * Worker for rtStrmFlushAndCloseAll.
+ */
+static void rtStrmFlushAndClose(PRTSTREAM pStream)
+{
+    pStream->u32Magic = ~RTSTREAM_MAGIC;
+    RTFILE hFile = rtStrmFlushAndCleanup(pStream);
+    if (hFile != NIL_RTFILE)
+        RTFileClose(hFile);
+    RTMemFree(pStream);
+}
+
+
+/**
+ * Flushes and cleans up the standard streams, should flush and close all others
+ * too but doesn't yet...
+ */
+DECLCALLBACK(void) rtStrmFlushAndCloseAll(void)
+{
+    /*
+     * Flush the standard handles.
+     */
+    rtStrmFlushAndCleanup(&g_StdOut);
+    rtStrmFlushAndCleanup(&g_StdErr);
+    rtStrmFlushAndCleanup(&g_StdIn);
+
+    /*
+     * Make a list of the rest and flush+close those too.
+     */
+    if (RTOnceWasInitialized(&g_StreamListOnce))
+    {
+        RTCritSectDelete(&g_StreamListCritSect);
+
+        PRTSTREAM pStream;
+        while ((pStream = RTListRemoveFirst(&g_StreamList, RTSTREAM, ListEntry)) != NULL)
+            rtStrmFlushAndClose(pStream);
+
+        RTOnceReset(&g_StreamListOnce);
+    }
+}
+
+# ifdef IPRT_COMPILER_TERM_CALLBACK
+IPRT_COMPILER_TERM_CALLBACK(rtStrmFlushAndCloseAll);
+# endif
+
+#endif /* RTSTREAM_STANDALONE */
+
+
+RTR3DECL(int) RTStrmRewind(PRTSTREAM pStream)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSTREAM_STANDALONE
+    rtStrmLock(pStream);
+    int const rc1 = rtStrmBufFlushWriteMaybe(pStream, true /*fInvalidate*/);
+    int const rc2 = RTFileSeek(rtStrmGetFile(pStream), 0, RTFILE_SEEK_BEGIN, NULL);
+    int rc = RT_SUCCESS(rc1) ? rc2 : rc1;
+    ASMAtomicWriteS32(&pStream->i32Error, rc);
+    rtStrmUnlock(pStream);
+#else
+    clearerr(pStream->pFile);
+    errno = 0;
+    int rc;
+    if (!fseek(pStream->pFile, 0, SEEK_SET))
+        rc = VINF_SUCCESS;
+    else
+        rc = RTErrConvertFromErrno(errno);
+    ASMAtomicWriteS32(&pStream->i32Error, rc);
+#endif
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmSeek(PRTSTREAM pStream, RTFOFF off, uint32_t uMethod)
+{
+    AssertReturn(uMethod <= RTFILE_SEEK_END, VERR_INVALID_PARAMETER);
+#ifdef RTSTREAM_STANDALONE
+    rtStrmLock(pStream);
+    int rc = rtStrmBufFlushWriteMaybe(pStream, true /*fInvalidate*/);
+    if (RT_SUCCESS(rc))
+        rc = RTFileSeek(rtStrmGetFile(pStream), off, uMethod, NULL);
+    if (RT_FAILURE(rc))
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+    rtStrmUnlock(pStream);
+#else
+    int const iCrtMethod = uMethod == RTFILE_SEEK_BEGIN ? SEEK_SET : uMethod == RTFILE_SEEK_CURRENT ? SEEK_CUR : SEEK_END;
+    errno = 0;
+    int rc;
+# ifdef _MSC_VER
+    if (!_fseeki64(pStream->pFile, off, iCrtMethod))
+# else
+    if (!fseeko(pStream->pFile, off, iCrtMethod))
+# endif
+        rc = VINF_SUCCESS;
+    else
+        rc = RTErrConvertFromErrno(errno);
+    ASMAtomicWriteS32(&pStream->i32Error, rc);
+#endif
+    return rc;
+}
+
+
+RTR3DECL(RTFOFF) RTStrmTell(PRTSTREAM pStream)
+{
+#ifdef RTSTREAM_STANDALONE
+    uint64_t off = 0;
+    rtStrmLock(pStream);
+    int rc = pStream->i32Error;
+    if (RT_SUCCESS(rc))
+    {
+        RTFILE const hFile = rtStrmGetFile(pStream);
+        if (hFile != NIL_RTFILE)
+        {
+            rc = RTFileSeek(hFile, 0, RTFILE_SEEK_CURRENT, &off);
+            if (RT_SUCCESS(rc))
+            {
+                switch (pStream->enmBufDir)
+                {
+                    case RTSTREAMBUFDIR_READ:
+                        /* Subtract unconsumed chars and removed '\r' characters. */
+                        off -= pStream->offBufEnd - pStream->offBufFirst;
+                        if (!pStream->fBinary)
+                            for (size_t offBuf = pStream->offBufFirst; offBuf < pStream->offBufEnd; offBuf++)
+                                off -= ASMBitTest(pStream->pbmBuf, (int32_t)offBuf);
+                        break;
+                    case RTSTREAMBUFDIR_WRITE:
+                        /* Add unwrittend chars in the buffer. */
+                        off += pStream->offBufEnd - pStream->offBufFirst;
+                        break;
+                    default:
+                        AssertFailed();
+                    case RTSTREAMBUFDIR_NONE:
+                        break;
+                }
+            }
+        }
+        else
+            rc = VERR_INVALID_HANDLE;
+    }
+    if (RT_FAILURE(rc))
+    {
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+        off = rc;
+    }
+    rtStrmUnlock(pStream);
+#else
+# ifdef _MSC_VER
+    RTFOFF off = _ftelli64(pStream->pFile);
+# else
+    RTFOFF off = ftello(pStream->pFile);
+# endif
+    if (off < 0)
+    {
+        int rc = RTErrConvertFromErrno(errno);
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+        off = rc;
+    }
+#endif
+    return off;
+}
+
+
+/**
+ * Recheck the stream mode.
+ *
+ * @param   pStream             The stream (locked).
+ */
+static void rtStreamRecheckMode(PRTSTREAM pStream)
+{
+#if (defined(RT_OS_WINDOWS) || defined(RT_OS_OS2)) && !defined(RTSTREAM_STANDALONE)
+    int fh = fileno(pStream->pFile);
+    if (fh >= 0)
+    {
+        int fExpected = pStream->fBinary ? _O_BINARY : _O_TEXT;
+        int fActual   = _setmode(fh, fExpected);
+        if (fActual != -1 && fExpected != (fActual & (_O_BINARY | _O_TEXT)))
+        {
+            fActual = _setmode(fh, fActual & (_O_BINARY | _O_TEXT));
+            pStream->fBinary = !(fActual & _O_TEXT);
+        }
+    }
+#else
+    NOREF(pStream);
+#endif
+    pStream->fRecheckMode = false;
+}
+
+
+RTR3DECL(int) RTStrmReadEx(PRTSTREAM pStream, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSTREAM_STANDALONE
+    rtStrmLock(pStream);
+    int rc = rtStrmBufCheckErrorAndSwitchToReadMode(pStream);
+#else
+    int rc = pStream->i32Error;
+#endif
+    if (RT_SUCCESS(rc))
+    {
+        if (pStream->fRecheckMode)
+            rtStreamRecheckMode(pStream);
+
+#ifdef RTSTREAM_STANDALONE
+
+        /*
+         * Copy data thru the read buffer for now as that'll handle both binary
+         * and text modes seamlessly.  We could optimize larger reads here when
+         * in binary mode, that can wait till the basics work, I think.
+         */
+        size_t cbTotal = 0;
+        if (cbToRead > 0)
+            for (;;)
+            {
+                size_t cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+                if (cbInBuffer > 0)
+                {
+                    size_t cbToCopy = RT_MIN(cbInBuffer, cbToRead);
+                    memcpy(pvBuf, &pStream->pchBuf[pStream->offBufFirst], cbToCopy);
+                    cbTotal  += cbToRead;
+                    cbToRead -= cbToCopy;
+                    pvBuf     = (char *)pvBuf + cbToCopy;
+                    if (!cbToRead)
+                        break;
+                }
+                rc = rtStrmBufFill(pStream);
+                if (RT_SUCCESS(rc))
+                { /* likely */ }
+                else
+                {
+                    if (rc == VERR_EOF && pcbRead && cbTotal > 0)
+                        rc = VINF_EOF;
+                    break;
+                }
+            }
+        if (pcbRead)
+            *pcbRead = cbTotal;
+
+#else  /* !RTSTREAM_STANDALONE */
+        if (pcbRead)
+        {
+            /*
+             * Can do with a partial read.
+             */
+            *pcbRead = fread(pvBuf, 1, cbToRead, pStream->pFile);
+            if (    *pcbRead == cbToRead
+                || !ferror(pStream->pFile))
+                rc = VINF_SUCCESS;
+            else if (feof(pStream->pFile))
+                rc = *pcbRead ? VINF_EOF : VERR_EOF;
+            else if (ferror(pStream->pFile))
+                rc = VERR_READ_ERROR;
+            else
+            {
+                AssertMsgFailed(("This shouldn't happen\n"));
+                rc = VERR_INTERNAL_ERROR;
+            }
+        }
+        else
+        {
+            /*
+             * Must read it all!
+             */
+            if (fread(pvBuf, cbToRead, 1, pStream->pFile) == 1)
+                rc = VINF_SUCCESS;
+            /* possible error/eof. */
+            else if (feof(pStream->pFile))
+                rc = VERR_EOF;
+            else if (ferror(pStream->pFile))
+                rc = VERR_READ_ERROR;
+            else
+            {
+                AssertMsgFailed(("This shouldn't happen\n"));
+                rc = VERR_INTERNAL_ERROR;
+            }
+        }
+#endif /* !RTSTREAM_STANDALONE */
+        if (RT_FAILURE(rc))
+            ASMAtomicWriteS32(&pStream->i32Error, rc);
+    }
+#ifdef RTSTREAM_STANDALONE
+    rtStrmUnlock(pStream);
+#endif
+    return rc;
+}
+
+
+/**
+ * Check if the input text is valid UTF-8.
+ *
+ * @returns true/false.
+ * @param   pvBuf               Pointer to the buffer.
+ * @param   cbBuf               Size of the buffer.
+ */
+static bool rtStrmIsUtf8Text(const void *pvBuf, size_t cbBuf)
+{
+    NOREF(pvBuf);
+    NOREF(cbBuf);
+    /** @todo not sure this is a good idea... Better redefine RTStrmWrite. */
+    return false;
+}
+
+
+#if defined(RT_OS_WINDOWS) && !defined(RTSTREAM_STANDALONE)
+
+/**
+ * Check if the stream is for a Window console.
+ *
+ * @returns true / false.
+ * @param   pStream             The stream.
+ * @param   phCon               Where to return the console handle.
+ */
+static bool rtStrmIsConsoleUnlocked(PRTSTREAM pStream, HANDLE *phCon)
+{
+    int fh = fileno(pStream->pFile);
+    if (isatty(fh))
+    {
+        DWORD dwMode;
+        HANDLE hCon = (HANDLE)_get_osfhandle(fh);
+        if (GetConsoleMode(hCon, &dwMode))
+        {
+            *phCon = hCon;
+            return true;
+        }
+    }
+    return false;
+}
+
+
+static int rtStrmWriteWinConsoleLocked(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten, HANDLE hCon)
+{
+    int rc;
+# ifdef HAVE_FWRITE_UNLOCKED
+    if (!fflush_unlocked(pStream->pFile))
+# else
+    if (!fflush(pStream->pFile))
+# endif
+    {
+        /** @todo Consider buffering later. For now, we'd rather correct output than
+         *        fast output. */
+        DWORD    cwcWritten = 0;
+        PRTUTF16 pwszSrc = NULL;
+        size_t   cwcSrc = 0;
+        rc = RTStrToUtf16Ex((const char *)pvBuf, cbToWrite, &pwszSrc, 0, &cwcSrc);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+        {
+            if (!WriteConsoleW(hCon, pwszSrc, (DWORD)cwcSrc, &cwcWritten, NULL))
+            {
+                /* try write char-by-char to avoid heap problem. */
+                cwcWritten = 0;
+                while (cwcWritten != cwcSrc)
+                {
+                    DWORD cwcThis;
+                    if (!WriteConsoleW(hCon, &pwszSrc[cwcWritten], 1, &cwcThis, NULL))
+                    {
+                        if (!pcbWritten || cwcWritten == 0)
+                            rc = RTErrConvertFromErrno(GetLastError());
+                        break;
+                    }
+                    if (cwcThis != 1) /* Unable to write current char (amount)? */
+                        break;
+                    cwcWritten++;
+                }
+            }
+            if (RT_SUCCESS(rc))
+            {
+                if (cwcWritten == cwcSrc)
+                {
+                    if (pcbWritten)
+                        *pcbWritten = cbToWrite;
+                }
+                else if (pcbWritten)
+                {
+                    PCRTUTF16   pwszCur = pwszSrc;
+                    const char *pszCur  = (const char *)pvBuf;
+                    while ((uintptr_t)(pwszCur - pwszSrc) < cwcWritten)
+                    {
+                        RTUNICP CpIgnored;
+                        RTUtf16GetCpEx(&pwszCur, &CpIgnored);
+                        RTStrGetCpEx(&pszCur, &CpIgnored);
+                    }
+                    *pcbWritten = pszCur - (const char *)pvBuf;
+                }
+                else
+                    rc = VERR_WRITE_ERROR;
+            }
+            RTUtf16Free(pwszSrc);
+        }
+    }
+    else
+        rc = RTErrConvertFromErrno(errno);
+    return rc;
+}
+
+#endif /* RT_OS_WINDOWS */
+
+static int rtStrmWriteWorkerLocked(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten, bool fMustWriteAll)
+{
+#ifdef RTSTREAM_STANDALONE
+    /*
+     * Check preconditions.
+     */
+    Assert(pStream->enmBufDir    == RTSTREAMBUFDIR_WRITE);
+    Assert(pStream->cbBufAlloc   >= 256);
+    Assert(pStream->offBufFirst  <= pStream->cbBufAlloc);
+    Assert(pStream->offBufEnd    <= pStream->cbBufAlloc);
+    Assert(pStream->offBufFirst  <= pStream->offBufEnd);
+
+    /*
+     * We write everything via the buffer, letting the buffer flushing take
+     * care of console output hacks and similar.
+     */
+    RT_NOREF(fMustWriteAll);
+    int    rc      = VINF_SUCCESS;
+    size_t cbTotal = 0;
+    if (cbToWrite > 0)
+    {
+# ifdef RTSTREAM_WITH_TEXT_MODE
+        const char *pchLf;
+        if (   !pStream->fBinary
+            && (pchLf = (const char *)memchr(pvBuf, '\n', cbToWrite)) != NULL)
+            for (;;)
+            {
+                /* Deal with everything up to the newline. */
+                size_t const cbToLf = (size_t)(pchLf - (const char *)pvBuf);
+                if (cbToLf > 0)
+                {
+                    rc = rtStrmBufCopyTo(pStream, pvBuf, cbToLf, &cbTotal);
+                    if (RT_FAILURE(rc))
+                        break;
+                }
+
+                /* Copy the CRLF sequence into the buffer in one go to avoid complications. */
+                if (pStream->cbBufAlloc - pStream->offBufEnd < 2)
+                {
+                    rc = rtStrmBufFlushWrite(pStream, pStream->offBufEnd - pStream->offBufFirst);
+                    if (RT_FAILURE(rc))
+                        break;
+                    Assert(pStream->cbBufAlloc - pStream->offBufEnd >= 2);
+                }
+                pStream->pchBuf[pStream->offBufEnd++] = '\r';
+                pStream->pchBuf[pStream->offBufEnd++] = '\n';
+
+                /* Advance past the newline. */
+                pvBuf               = (const char *)pvBuf + 1 + cbToLf;
+                cbTotal            += 1 + cbToLf;
+                cbToWrite          -= 1 + cbToLf;
+                if (!cbToWrite)
+                    break;
+
+                /* More newlines? */
+                pchLf = (const char *)memchr(pvBuf, '\n', cbToWrite);
+                if (!pchLf)
+                {
+                    rc = rtStrmBufCopyTo(pStream, pvBuf, cbToWrite, &cbTotal);
+                    break;
+                }
+            }
+        else
+# endif
+            rc = rtStrmBufCopyTo(pStream, pvBuf, cbToWrite, &cbTotal);
+
+        /*
+         * If line buffered or unbuffered, we probably have to do some flushing now.
+         */
+        if (RT_SUCCESS(rc) && pStream->enmBufStyle != RTSTREAMBUFSTYLE_FULL)
+        {
+            Assert(pStream->enmBufStyle == RTSTREAMBUFSTYLE_LINE || pStream->enmBufStyle == RTSTREAMBUFSTYLE_UNBUFFERED);
+            size_t cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+            if (cbInBuffer > 0)
+            {
+                if (   pStream->enmBufStyle != RTSTREAMBUFSTYLE_LINE
+                    || pStream->pchBuf[pStream->offBufEnd - 1] == '\n')
+                    rc = rtStrmBufFlushWrite(pStream, cbInBuffer);
+                else
+                {
+                    const char *pchToFlush = &pStream->pchBuf[pStream->offBufFirst];
+                    const char *pchLastLf  = (const char *)memrchr(pchToFlush, '\n', cbInBuffer);
+                    if (pchLastLf)
+                        rc = rtStrmBufFlushWrite(pStream, (size_t)(&pchLastLf[1] - pchToFlush));
+                }
+            }
+        }
+    }
+    if (pcbWritten)
+        *pcbWritten = cbTotal;
+    return rc;
+
+
+#else
+    if (!fMustWriteAll)
+    {
+        IPRT_ALIGNMENT_CHECKS_DISABLE(); /* glibc / mempcpy again */
+# ifdef HAVE_FWRITE_UNLOCKED
+        *pcbWritten = fwrite_unlocked(pvBuf, 1, cbToWrite, pStream->pFile);
+# else
+        *pcbWritten = fwrite(pvBuf, 1, cbToWrite, pStream->pFile);
+# endif
+        IPRT_ALIGNMENT_CHECKS_ENABLE();
+        if (    *pcbWritten == cbToWrite
+# ifdef HAVE_FWRITE_UNLOCKED
+            ||  !ferror_unlocked(pStream->pFile))
+# else
+            ||  !ferror(pStream->pFile))
+# endif
+            return VINF_SUCCESS;
+    }
+    else
+    {
+        /* Must write it all! */
+        IPRT_ALIGNMENT_CHECKS_DISABLE(); /* glibc / mempcpy again */
+# ifdef HAVE_FWRITE_UNLOCKED
+        size_t cbWritten = fwrite_unlocked(pvBuf, cbToWrite, 1, pStream->pFile);
+# else
+        size_t cbWritten = fwrite(pvBuf, cbToWrite, 1, pStream->pFile);
+# endif
+        if (pcbWritten)
+            *pcbWritten = cbWritten;
+        IPRT_ALIGNMENT_CHECKS_ENABLE();
+        if (cbWritten == 1)
+            return VINF_SUCCESS;
+# ifdef HAVE_FWRITE_UNLOCKED
+        if (!ferror_unlocked(pStream->pFile))
+# else
+        if (!ferror(pStream->pFile))
+# endif
+            return VINF_SUCCESS; /* WEIRD! But anyway... */
+    }
+    return VERR_WRITE_ERROR;
+#endif
+}
+
+
+/**
+ * Internal write API, stream lock already held.
+ *
+ * @returns IPRT status code.
+ * @param   pStream             The stream.
+ * @param   pvBuf               What to write.
+ * @param   cbToWrite           How much to write.
+ * @param   pcbWritten          Where to optionally return the number of bytes
+ *                              written.
+ * @param   fSureIsText         Set if we're sure this is UTF-8 text already.
+ */
+static int rtStrmWriteLocked(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten, bool fSureIsText)
+{
+#ifdef RTSTREAM_STANDALONE
+    int rc = rtStrmBufCheckErrorAndSwitchToWriteMode(pStream);
+#else
+    int rc = pStream->i32Error;
+#endif
+    if (RT_FAILURE(rc))
+        return rc;
+    if (pStream->fRecheckMode)
+        rtStreamRecheckMode(pStream);
+
+#if defined(RT_OS_WINDOWS) && !defined(RTSTREAM_STANDALONE)
+    /*
+     * Use the unicode console API when possible in order to avoid stuff
+     * getting lost in unnecessary code page translations.
+     */
+    HANDLE hCon;
+    if (rtStrmIsConsoleUnlocked(pStream, &hCon))
+        rc = rtStrmWriteWinConsoleLocked(pStream, pvBuf, cbToWrite, pcbWritten, hCon);
+#else
+    if (0) { }
+#endif /* RT_OS_WINDOWS && !RTSTREAM_STANDALONE */
+
+    /*
+     * If we're sure it's text output, convert it from UTF-8 to the current
+     * code page before printing it.
+     *
+     * Note! Partial writes are not supported in this scenario because we
+     *       cannot easily report back a written length matching the input.
+     */
+    /** @todo Skip this if the current code set is UTF-8. */
+    else if (   pStream->fCurrentCodeSet
+             && !pStream->fBinary
+             && (   fSureIsText
+                 || rtStrmIsUtf8Text(pvBuf, cbToWrite))
+            )
+    {
+        char       *pszSrcFree = NULL;
+        const char *pszSrc     = (const char *)pvBuf;
+        if (pszSrc[cbToWrite - 1])
+        {
+            pszSrc = pszSrcFree = RTStrDupN(pszSrc, cbToWrite);
+            if (pszSrc == NULL)
+                rc = VERR_NO_STR_MEMORY;
+        }
+        if (RT_SUCCESS(rc))
+        {
+            char *pszSrcCurCP;
+            rc = RTStrUtf8ToCurrentCP(&pszSrcCurCP, pszSrc);
+            AssertRC(rc);
+            if (RT_SUCCESS(rc))
+            {
+                size_t  cchSrcCurCP = strlen(pszSrcCurCP);
+                size_t  cbWritten = 0;
+                rc = rtStrmWriteWorkerLocked(pStream, pszSrcCurCP, cchSrcCurCP, &cbWritten, true /*fMustWriteAll*/);
+                if (pcbWritten)
+                    *pcbWritten = cbWritten == cchSrcCurCP ? cbToWrite : 0;
+                RTStrFree(pszSrcCurCP);
+            }
+            RTStrFree(pszSrcFree);
+        }
+    }
+    /*
+     * Otherwise, just write it as-is.
+     */
+    else
+        rc = rtStrmWriteWorkerLocked(pStream, pvBuf, cbToWrite, pcbWritten, pcbWritten == NULL);
+
+    /*
+     * Update error status on failure and return.
+     *
+     * We ignore failures from RTStrUtf8ToCurrentCP and RTStrToUtf16Ex regarding
+     * invalid UTF-8 encoding, as that's an input issue and shouldn't affect the
+     * stream state.
+     */
+    if (RT_FAILURE(rc) && rc != VERR_INVALID_UTF8_ENCODING)
+        ASMAtomicWriteS32(&pStream->i32Error, rc);
+    return rc;
+}
+
+
+/**
+ * Internal write API.
+ *
+ * @returns IPRT status code.
+ * @param   pStream             The stream.
+ * @param   pvBuf               What to write.
+ * @param   cbToWrite           How much to write.
+ * @param   pcbWritten          Where to optionally return the number of bytes
+ *                              written.
+ * @param   fSureIsText         Set if we're sure this is UTF-8 text already.
+ */
+DECLINLINE(int) rtStrmWrite(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten, bool fSureIsText)
+{
+    rtStrmLock(pStream);
+    int rc = rtStrmWriteLocked(pStream, pvBuf, cbToWrite, pcbWritten, fSureIsText);
+    rtStrmUnlock(pStream);
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmWriteEx(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    AssertReturn(RT_VALID_PTR(pStream) && pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_PARAMETER);
+    return rtStrmWrite(pStream, pvBuf, cbToWrite, pcbWritten, false);
+}
+
+
+RTR3DECL(int) RTStrmGetCh(PRTSTREAM pStream)
+{
+    unsigned char ch;
+    int rc = RTStrmReadEx(pStream, &ch, 1, NULL);
+    if (RT_SUCCESS(rc))
+        return ch;
+    return -1;
+}
+
+
+RTR3DECL(int) RTStrmPutCh(PRTSTREAM pStream, int ch)
+{
+    return rtStrmWrite(pStream, &ch, 1, NULL, true /*fSureIsText*/);
+}
+
+
+RTR3DECL(int) RTStrmPutStr(PRTSTREAM pStream, const char *pszString)
+{
+    size_t cch = strlen(pszString);
+    return rtStrmWrite(pStream, pszString, cch, NULL, true /*fSureIsText*/);
+}
+
+
+RTR3DECL(int) RTStrmGetLine(PRTSTREAM pStream, char *pszString, size_t cbString)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pszString, VERR_INVALID_POINTER);
+    AssertReturn(cbString >= 2, VERR_INVALID_PARAMETER);
+
+    rtStrmLock(pStream);
+
+#ifdef RTSTREAM_STANDALONE
+    int rc = rtStrmBufCheckErrorAndSwitchToReadMode(pStream);
+#else
+    int rc = pStream->i32Error;
+#endif
+    if (RT_SUCCESS(rc))
+    {
+        cbString--;            /* Reserve space for the terminator. */
+
+#ifdef RTSTREAM_STANDALONE
+        char * const pszStringStart = pszString;
+#endif
+        for (;;)
+        {
+#ifdef RTSTREAM_STANDALONE
+            /* Make sure there is at least one character in the buffer: */
+            size_t cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+            if (cbInBuffer == 0)
+            {
+                rc = rtStrmBufFill(pStream);
+                if (RT_SUCCESS(rc))
+                    cbInBuffer = pStream->offBufEnd - pStream->offBufFirst;
+                else
+                    break;
+            }
+
+            /* Scan the buffer content terminating on a '\n', '\r\n' and '\0' sequence. */
+            const char *pchSrc     = &pStream->pchBuf[pStream->offBufFirst];
+            const char *pchNewline = (const char *)memchr(pchSrc, '\n', cbInBuffer);
+            const char *pchTerm    = (const char *)memchr(pchSrc, '\0', cbInBuffer);
+            size_t      cbCopy;
+            size_t      cbAdvance;
+            bool        fStop      = pchNewline || pchTerm;
+            if (!fStop)
+                cbAdvance = cbCopy = cbInBuffer;
+            else if (!pchTerm || (pchNewline && pchTerm && (uintptr_t)pchNewline < (uintptr_t)pchTerm))
+            {
+                cbCopy    = (size_t)(pchNewline - pchSrc);
+                cbAdvance = cbCopy + 1;
+                if (cbCopy && pchNewline[-1] == '\r')
+                    cbCopy--;
+                else if (cbCopy == 0 && (uintptr_t)pszString > (uintptr_t)pszStringStart && pszString[-1] == '\r')
+                    pszString--, cbString++; /* drop trailing '\r' that it turns out was followed by '\n' */
+            }
+            else
+            {
+                cbCopy    = (size_t)(pchTerm - pchSrc);
+                cbAdvance = cbCopy + 1;
+            }
+
+            /* Adjust for available space in the destination buffer, copy over the string
+               characters and advance the buffer position (even on overflow). */
+            if (cbCopy <= cbString)
+                pStream->offBufFirst += cbAdvance;
+            else
+            {
+                rc        = VERR_BUFFER_OVERFLOW;
+                fStop     = true;
+                cbCopy    = cbString;
+                pStream->offBufFirst += cbString;
+            }
+
+            memcpy(pszString, pchSrc, cbCopy);
+            pszString += cbCopy;
+            cbString  -= cbCopy;
+
+            if (fStop)
+                break;
+
+#else  /* !RTSTREAM_STANDALONE */
+# ifdef HAVE_FWRITE_UNLOCKED /** @todo darwin + freebsd(?) has fgetc_unlocked but not fwrite_unlocked, optimize... */
+            int ch = fgetc_unlocked(pStream->pFile);
+# else
+            int ch = fgetc(pStream->pFile);
+# endif
+
+            /* Deal with \r\n sequences here. We'll return lone CR, but
+               treat CRLF as LF. */
+            if (ch == '\r')
+            {
+# ifdef HAVE_FWRITE_UNLOCKED /** @todo darwin + freebsd(?) has fgetc_unlocked but not fwrite_unlocked, optimize... */
+                ch = fgetc_unlocked(pStream->pFile);
+# else
+                ch = fgetc(pStream->pFile);
+# endif
+                if (ch == '\n')
+                    break;
+
+                *pszString++ = '\r';
+                if (--cbString <= 0)
+                {
+                    /* yeah, this is an error, we dropped a character. */
+                    rc = VERR_BUFFER_OVERFLOW;
+                    break;
+                }
+            }
+
+            /* Deal with end of file. */
+            if (ch == EOF)
+            {
+# ifdef HAVE_FWRITE_UNLOCKED
+                if (feof_unlocked(pStream->pFile))
+# else
+                if (feof(pStream->pFile))
+# endif
+                {
+                    rc = VERR_EOF;
+                    break;
+                }
+# ifdef HAVE_FWRITE_UNLOCKED
+                if (ferror_unlocked(pStream->pFile))
+# else
+                if (ferror(pStream->pFile))
+# endif
+                    rc = VERR_READ_ERROR;
+                else
+                {
+                    AssertMsgFailed(("This shouldn't happen\n"));
+                    rc = VERR_INTERNAL_ERROR;
+                }
+                break;
+            }
+
+            /* Deal with null terminator and (lone) new line. */
+            if (ch == '\0' || ch == '\n')
+                break;
+
+            /* No special character, append it to the return string. */
+            *pszString++ = ch;
+            if (--cbString <= 0)
+            {
+                rc = VINF_BUFFER_OVERFLOW;
+                break;
+            }
+#endif /* !RTSTREAM_STANDALONE */
+        }
+
+        *pszString = '\0';
+        if (RT_FAILURE(rc))
+            ASMAtomicWriteS32(&pStream->i32Error, rc);
+    }
+
+    rtStrmUnlock(pStream);
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmFlush(PRTSTREAM pStream)
+{
+    AssertPtrReturn(pStream, VERR_INVALID_HANDLE);
+    AssertReturn(pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSTREAM_STANDALONE
+    rtStrmLock(pStream);
+    int rc = rtStrmBufFlushWriteMaybe(pStream, true /*fInvalidate*/);
+    rtStrmUnlock(pStream);
+    return rc;
+
+#else
+    if (!fflush(pStream->pFile))
+        return VINF_SUCCESS;
+    return RTErrConvertFromErrno(errno);
+#endif
+}
+
+
+/**
+ * Output callback.
+ *
+ * @returns number of bytes written.
+ * @param   pvArg       User argument.
+ * @param   pachChars   Pointer to an array of utf-8 characters.
+ * @param   cchChars    Number of bytes in the character array pointed to by pachChars.
+ */
+static DECLCALLBACK(size_t) rtstrmOutput(void *pvArg, const char *pachChars, size_t cchChars)
+{
+    if (cchChars)
+        rtStrmWriteLocked((PRTSTREAM)pvArg, pachChars, cchChars, NULL, true /*fSureIsText*/);
+    /* else: ignore termination call. */
+    return cchChars;
+}
+
+
+RTR3DECL(int) RTStrmPrintfV(PRTSTREAM pStream, const char *pszFormat, va_list args)
+{
+    AssertReturn(RT_VALID_PTR(pStream) && pStream->u32Magic == RTSTREAM_MAGIC, VERR_INVALID_PARAMETER);
+    int rc = pStream->i32Error;
+    if (RT_SUCCESS(rc))
+    {
+        rtStrmLock(pStream);
+//        pStream->fShouldFlush = true;
+        rc = (int)RTStrFormatV(rtstrmOutput, pStream, NULL, NULL, pszFormat, args);
+        rtStrmUnlock(pStream);
+        Assert(rc >= 0);
+    }
+    else
+        rc = -1;
+    return rc;
+}
+
+
+RTR3DECL(int) RTStrmPrintf(PRTSTREAM pStream, const char *pszFormat, ...)
+{
+    va_list args;
+    va_start(args, pszFormat);
+    int rc = RTStrmPrintfV(pStream, pszFormat, args);
+    va_end(args);
+    return rc;
+}
+
+
+RTDECL(void) RTStrmDumpPrintfV(void *pvUser, const char *pszFormat, va_list va)
+{
+    RTStrmPrintfV(pvUser ? (PRTSTREAM)pvUser : g_pStdOut, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTPrintfV(const char *pszFormat, va_list args)
+{
+    return RTStrmPrintfV(g_pStdOut, pszFormat, args);
+}
+
+
+RTR3DECL(int) RTPrintf(const char *pszFormat, ...)
+{
+    va_list args;
+    va_start(args, pszFormat);
+    int rc = RTStrmPrintfV(g_pStdOut, pszFormat, args);
+    va_end(args);
+    return rc;
+}
+
+
+/**
+ * Outputs @a cchIndent spaces.
+ */
+static void rtStrmWrapppedIndent(RTSTRMWRAPPEDSTATE *pState, uint32_t cchIndent)
+{
+    static const char s_szSpaces[] = "                                                ";
+    while (cchIndent)
+    {
+        uint32_t cchToWrite = RT_MIN(cchIndent, sizeof(s_szSpaces) - 1);
+        int rc = RTStrmWrite(pState->pStream, s_szSpaces, cchToWrite);
+        if (RT_SUCCESS(rc))
+            cchIndent -= cchToWrite;
+        else
+        {
+            pState->rcStatus = rc;
+            break;
+        }
+    }
+}
+
+
+/**
+ * Flushes the current line.
+ *
+ * @param   pState      The wrapped output state.
+ * @param   fPartial    Set if partial flush due to buffer overflow, clear when
+ *                      flushing due to '\n'.
+ */
+static void rtStrmWrappedFlushLine(RTSTRMWRAPPEDSTATE *pState, bool fPartial)
+{
+    /*
+     * Check indentation in case we need to split the line later.
+     */
+    uint32_t cchIndent = pState->cchIndent;
+    if (cchIndent == UINT32_MAX)
+    {
+        pState->cchIndent = 0;
+        cchIndent = pState->cchHangingIndent;
+        while (RT_C_IS_BLANK(pState->szLine[cchIndent]))
+            cchIndent++;
+    }
+
+    /*
+     * Do the flushing.
+     */
+    uint32_t cchLine = pState->cchLine;
+    Assert(cchLine < sizeof(pState->szLine));
+    while (cchLine >= pState->cchWidth || !fPartial)
+    {
+        /*
+         * Hopefully we don't need to do any wrapping ...
+         */
+        uint32_t offSplit;
+        if (pState->cchIndent + cchLine <= pState->cchWidth)
+        {
+            if (!fPartial)
+            {
+                rtStrmWrapppedIndent(pState, pState->cchIndent);
+                pState->szLine[cchLine] = '\n';
+                int rc = RTStrmWrite(pState->pStream, pState->szLine, cchLine + 1);
+                if (RT_FAILURE(rc))
+                    pState->rcStatus = rc;
+                pState->cLines   += 1;
+                pState->cchLine   = 0;
+                pState->cchIndent = UINT32_MAX;
+                return;
+            }
+
+            /*
+             * ... no such luck.
+             */
+            offSplit = cchLine;
+        }
+        else
+            offSplit = pState->cchWidth - pState->cchIndent;
+
+        /* Find the start of the current word: */
+        while (offSplit > 0 && !RT_C_IS_BLANK(pState->szLine[offSplit - 1]))
+            offSplit--;
+
+        /* Skip spaces. */
+        while (offSplit > 0 && RT_C_IS_BLANK(pState->szLine[offSplit - 1]))
+            offSplit--;
+        uint32_t offNextLine = offSplit;
+
+        /* If the first word + indent is wider than the screen width, so just output it in full. */
+        if (offSplit == 0) /** @todo Split words, look for hyphen...  This code is currently a bit crude. */
+        {
+            while (offSplit < cchLine && !RT_C_IS_BLANK(pState->szLine[offSplit]))
+                offSplit++;
+            offNextLine = offSplit;
+        }
+
+        while (offNextLine < cchLine && RT_C_IS_BLANK(pState->szLine[offNextLine]))
+            offNextLine++;
+
+        /*
+         * Output and advance.
+         */
+        rtStrmWrapppedIndent(pState, pState->cchIndent);
+        int rc = RTStrmWrite(pState->pStream, pState->szLine, offSplit);
+        if (RT_SUCCESS(rc))
+            rc = RTStrmPutCh(pState->pStream, '\n');
+        if (RT_FAILURE(rc))
+            pState->rcStatus = rc;
+
+        cchLine -= offNextLine;
+        pState->cchLine   = cchLine;
+        pState->cLines   += 1;
+        pState->cchIndent = cchIndent;
+        memmove(&pState->szLine[0], &pState->szLine[offNextLine], cchLine);
+    }
+
+    /* The indentation level is reset for each '\n' we process, so only save cchIndent if partial. */
+    pState->cchIndent = fPartial ? cchIndent : UINT32_MAX;
+}
+
+
+/**
+ * @callback_method_impl{FNRTSTROUTPUT}
+ */
+static DECLCALLBACK(size_t) rtStrmWrappedOutput(void *pvArg, const char *pachChars, size_t cbChars)
+{
+    RTSTRMWRAPPEDSTATE *pState = (RTSTRMWRAPPEDSTATE *)pvArg;
+    size_t const cchRet = cbChars;
+    while (cbChars > 0)
+    {
+        if (*pachChars == '\n')
+        {
+            rtStrmWrappedFlushLine(pState, false /*fPartial*/);
+            pachChars++;
+            cbChars--;
+        }
+        else
+        {
+            const char *pszEol      = (const char *)memchr(pachChars, '\n', cbChars);
+            size_t      cchToCopy   = pszEol ? (size_t)(pszEol - pachChars) : cbChars;
+            uint32_t    cchLine     = pState->cchLine;
+            Assert(cchLine < sizeof(pState->szLine));
+            bool const  fFlush      = cchLine + cchToCopy >= sizeof(pState->szLine);
+            if (fFlush)
+                cchToCopy = cchToCopy - sizeof(pState->szLine) - 1;
+
+            pState->cchLine = cchLine + (uint32_t)cchToCopy;
+            memcpy(&pState->szLine[cchLine], pachChars, cchToCopy);
+
+            pachChars += cchToCopy;
+            cbChars   -= cchToCopy;
+
+            if (fFlush)
+                rtStrmWrappedFlushLine(pState, true /*fPartial*/);
+        }
+    }
+    return cchRet;
+}
+
+
+RTDECL(int32_t) RTStrmWrappedPrintfV(PRTSTREAM pStream, uint32_t fFlags, const char *pszFormat, va_list va)
+{
+    /*
+     * Figure the output width and set up the rest of the output state.
+     */
+    RTSTRMWRAPPEDSTATE State;
+    State.pStream           = pStream;
+    State.cchLine           = fFlags & RTSTRMWRAPPED_F_LINE_OFFSET_MASK;
+    State.cLines            = 0;
+    State.rcStatus          = VINF_SUCCESS;
+    State.cchIndent         = UINT32_MAX;
+    State.cchHangingIndent  = 0;
+    if (fFlags & RTSTRMWRAPPED_F_HANGING_INDENT)
+    {
+        State.cchHangingIndent = (fFlags & RTSTRMWRAPPED_F_HANGING_INDENT_MASK) >> RTSTRMWRAPPED_F_HANGING_INDENT_SHIFT;
+        if (!State.cchHangingIndent)
+            State.cchHangingIndent = 4;
+    }
+
+    int rc = RTStrmQueryTerminalWidth(pStream, &State.cchWidth);
+    if (RT_SUCCESS(rc))
+        State.cchWidth = RT_MIN(State.cchWidth, RTSTRMWRAPPED_F_LINE_OFFSET_MASK + 1);
+    else
+    {
+        State.cchWidth = (uint32_t)fFlags & RTSTRMWRAPPED_F_NON_TERMINAL_WIDTH_MASK;
+        if (!State.cchWidth)
+            State.cchWidth = 80;
+    }
+    if (State.cchWidth < 32)
+        State.cchWidth = 32;
+    //State.cchWidth         -= 1; /* necessary here? */
+
+    /*
+     * Do the formatting.
+     */
+    RTStrFormatV(rtStrmWrappedOutput, &State, NULL, NULL, pszFormat, va);
+
+    /*
+     * Returning is simple if the buffer is empty.  Otherwise we'll have to
+     * perform a partial flush and write out whatever is left ourselves.
+     */
+    if (RT_SUCCESS(State.rcStatus))
+    {
+        if (State.cchLine == 0)
+            return State.cLines << 16;
+
+        rtStrmWrappedFlushLine(&State, true /*fPartial*/);
+        if (RT_SUCCESS(State.rcStatus) && State.cchLine > 0)
+        {
+            rtStrmWrapppedIndent(&State, State.cchIndent);
+            State.rcStatus = RTStrmWrite(State.pStream, State.szLine, State.cchLine);
+        }
+        if (RT_SUCCESS(State.rcStatus))
+            return RT_MIN(State.cchIndent + State.cchLine, RTSTRMWRAPPED_F_LINE_OFFSET_MASK) | (State.cLines << 16);
+    }
+    return State.rcStatus;
+}
+
+
+RTDECL(int32_t) RTStrmWrappedPrintf(PRTSTREAM pStream, uint32_t fFlags, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int32_t rcRet = RTStrmWrappedPrintfV(pStream, fFlags, pszFormat, va);
+    va_end(va);
+    return rcRet;
+}
+
diff --git a/src/VBox/Runtime/r3/tcp.cpp b/src/VBox/Runtime/r3/tcp.cpp
new file mode 100644
index 00000000..8e9988a6
--- /dev/null
+++ b/src/VBox/Runtime/r3/tcp.cpp
@@ -0,0 +1,1082 @@
+/* $Id: tcp.cpp $ */
+/** @file
+ * IPRT - TCP/IP.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/winsock2.h>
+#else
+# include <sys/types.h>
+# include <sys/socket.h>
+# include <errno.h>
+# include <netinet/in.h>
+# include <netinet/tcp.h>
+# include <arpa/inet.h>
+# include <netdb.h>
+# ifdef FIX_FOR_3_2
+#  include <fcntl.h>
+# endif
+#endif
+#include <limits.h>
+
+#include "internal/iprt.h"
+#include <iprt/tcp.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mempool.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/socket.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+
+#include "internal/magics.h"
+#include "internal/socket.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/* non-standard linux stuff (it seems). */
+#ifndef MSG_NOSIGNAL
+# define MSG_NOSIGNAL           0
+#endif
+#ifndef SHUT_RDWR
+# ifdef SD_BOTH
+#  define SHUT_RDWR             SD_BOTH
+# else
+#  define SHUT_RDWR             2
+# endif
+#endif
+#ifndef SHUT_WR
+# ifdef SD_SEND
+#  define SHUT_WR               SD_SEND
+# else
+#  define SHUT_WR               1
+# endif
+#endif
+
+/* fixup backlevel OSes. */
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+# define socklen_t              int
+#endif
+
+/** How many pending connection. */
+#define RTTCP_SERVER_BACKLOG    10
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * TCP Server state.
+ */
+typedef enum RTTCPSERVERSTATE
+{
+    /** Invalid. */
+    RTTCPSERVERSTATE_INVALID = 0,
+    /** Created. */
+    RTTCPSERVERSTATE_CREATED,
+    /** Listener thread is starting up. */
+    RTTCPSERVERSTATE_STARTING,
+    /** Accepting client connections. */
+    RTTCPSERVERSTATE_ACCEPTING,
+    /** Serving a client. */
+    RTTCPSERVERSTATE_SERVING,
+    /** Listener terminating. */
+    RTTCPSERVERSTATE_STOPPING,
+    /** Listener terminated. */
+    RTTCPSERVERSTATE_STOPPED,
+    /** Listener cleans up. */
+    RTTCPSERVERSTATE_DESTROYING
+} RTTCPSERVERSTATE;
+
+/*
+ * Internal representation of the TCP Server handle.
+ */
+typedef struct RTTCPSERVER
+{
+    /** The magic value (RTTCPSERVER_MAGIC). */
+    uint32_t volatile           u32Magic;
+    /** The server state. */
+    RTTCPSERVERSTATE volatile   enmState;
+    /** The server thread. */
+    RTTHREAD                    Thread;
+    /** The server socket. */
+    RTSOCKET volatile           hServerSocket;
+    /** The socket to the client currently being serviced.
+     * This is NIL_RTSOCKET when no client is serviced. */
+    RTSOCKET volatile           hClientSocket;
+    /** The connection function. */
+    PFNRTTCPSERVE               pfnServe;
+    /** Argument to pfnServer. */
+    void                       *pvUser;
+} RTTCPSERVER;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static DECLCALLBACK(int)  rtTcpServerThread(RTTHREAD ThreadSelf, void *pvServer);
+static int  rtTcpServerListen(PRTTCPSERVER pServer);
+static int  rtTcpServerListenCleanup(PRTTCPSERVER pServer);
+static int  rtTcpClose(RTSOCKET Sock, const char *pszMsg, bool fTryGracefulShutdown);
+
+
+/**
+ * Atomicly updates a socket variable.
+ * @returns The old handle value.
+ * @param   phSock          The socket handle variable to update.
+ * @param   hNew            The new socket handle value.
+ */
+DECLINLINE(RTSOCKET) rtTcpAtomicXchgSock(RTSOCKET volatile *phSock, const RTSOCKET hNew)
+{
+    RTSOCKET hRet;
+    ASMAtomicXchgHandle(phSock, hNew, &hRet);
+    return hRet;
+}
+
+
+/**
+ * Tries to change the TCP server state.
+ */
+DECLINLINE(bool) rtTcpServerTrySetState(PRTTCPSERVER pServer, RTTCPSERVERSTATE enmStateNew, RTTCPSERVERSTATE enmStateOld)
+{
+    bool fRc;
+    ASMAtomicCmpXchgSize(&pServer->enmState, enmStateNew, enmStateOld, fRc);
+    return fRc;
+}
+
+/**
+ * Changes the TCP server state.
+ */
+DECLINLINE(void) rtTcpServerSetState(PRTTCPSERVER pServer, RTTCPSERVERSTATE enmStateNew, RTTCPSERVERSTATE enmStateOld)
+{
+    bool fRc;
+    ASMAtomicCmpXchgSize(&pServer->enmState, enmStateNew, enmStateOld, fRc);
+    Assert(fRc); NOREF(fRc);
+}
+
+
+/**
+ * Closes the a socket (client or server).
+ *
+ * @returns IPRT status code.
+ */
+static int rtTcpServerDestroySocket(RTSOCKET volatile *pSock, const char *pszMsg, bool fTryGracefulShutdown)
+{
+    RTSOCKET hSocket = rtTcpAtomicXchgSock(pSock, NIL_RTSOCKET);
+    if (hSocket != NIL_RTSOCKET)
+    {
+        if (!fTryGracefulShutdown)
+            RTSocketShutdown(hSocket, true /*fRead*/, true /*fWrite*/);
+        return rtTcpClose(hSocket, pszMsg, fTryGracefulShutdown);
+    }
+    return VINF_TCP_SERVER_NO_CLIENT;
+}
+
+
+RTR3DECL(int)  RTTcpServerCreate(const char *pszAddress, unsigned uPort, RTTHREADTYPE enmType, const char *pszThrdName,
+                                 PFNRTTCPSERVE pfnServe, void *pvUser, PPRTTCPSERVER ppServer)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfnServe, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszThrdName, VERR_INVALID_POINTER);
+    AssertPtrReturn(ppServer, VERR_INVALID_POINTER);
+
+    /*
+     * Create the server.
+     */
+    PRTTCPSERVER pServer;
+    int rc = RTTcpServerCreateEx(pszAddress, uPort, &pServer);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Create the listener thread.
+         */
+        RTMemPoolRetain(pServer);
+        pServer->enmState   = RTTCPSERVERSTATE_STARTING;
+        pServer->pvUser     = pvUser;
+        pServer->pfnServe   = pfnServe;
+        rc = RTThreadCreate(&pServer->Thread, rtTcpServerThread, pServer, 0, enmType, /*RTTHREADFLAGS_WAITABLE*/0, pszThrdName);
+        if (RT_SUCCESS(rc))
+        {
+            /* done */
+            if (ppServer)
+                *ppServer = pServer;
+            else
+                RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            return rc;
+        }
+        RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+
+        /*
+         * Destroy the server.
+         */
+        rtTcpServerSetState(pServer, RTTCPSERVERSTATE_CREATED, RTTCPSERVERSTATE_STARTING);
+        RTTcpServerDestroy(pServer);
+    }
+
+    return rc;
+}
+
+
+/**
+ * Server thread, loops accepting connections until it's terminated.
+ *
+ * @returns iprt status code. (ignored).
+ * @param   ThreadSelf      Thread handle.
+ * @param   pvServer        Server handle.
+ */
+static DECLCALLBACK(int)  rtTcpServerThread(RTTHREAD ThreadSelf, void *pvServer)
+{
+    PRTTCPSERVER    pServer = (PRTTCPSERVER)pvServer;
+    int             rc;
+    if (rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_ACCEPTING, RTTCPSERVERSTATE_STARTING))
+        rc = rtTcpServerListen(pServer);
+    else
+        rc = rtTcpServerListenCleanup(pServer);
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    NOREF(ThreadSelf);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTcpServerCreateEx(const char *pszAddress, uint32_t uPort, PPRTTCPSERVER ppServer)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(ppServer, VERR_INVALID_PARAMETER);
+
+    /*
+     * Resolve the address.
+     */
+    RTNETADDR LocalAddr;
+    int rc = RTSocketParseInetAddress(pszAddress, uPort, &LocalAddr);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Setting up socket.
+     */
+    RTSOCKET WaitSock;
+    rc = rtSocketCreate(&WaitSock, AF_INET, SOCK_STREAM, IPPROTO_TCP, false /*fInheritable*/);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Set socket options.
+         */
+        int fFlag = 1;
+        if (!rtSocketSetOpt(WaitSock, SOL_SOCKET, SO_REUSEADDR, &fFlag, sizeof(fFlag)))
+        {
+            /*
+             * Bind a name to a socket and set it listening for connections.
+             */
+            rc = rtSocketBind(WaitSock, &LocalAddr);
+            if (RT_SUCCESS(rc))
+                rc = rtSocketListen(WaitSock, RTTCP_SERVER_BACKLOG);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Create the server handle.
+                 */
+                PRTTCPSERVER pServer = (PRTTCPSERVER)RTMemPoolAlloc(RTMEMPOOL_DEFAULT, sizeof(*pServer));
+                if (pServer)
+                {
+                    pServer->u32Magic       = RTTCPSERVER_MAGIC;
+                    pServer->enmState       = RTTCPSERVERSTATE_CREATED;
+                    pServer->Thread         = NIL_RTTHREAD;
+                    pServer->hServerSocket  = WaitSock;
+                    pServer->hClientSocket  = NIL_RTSOCKET;
+                    pServer->pfnServe       = NULL;
+                    pServer->pvUser         = NULL;
+                    *ppServer = pServer;
+                    return VINF_SUCCESS;
+                }
+
+                /* bail out */
+                rc = VERR_NO_MEMORY;
+            }
+        }
+        else
+            AssertMsgFailed(("rtSocketSetOpt: %Rrc\n", rc));
+        rtTcpClose(WaitSock, "RTServerCreateEx", false /*fTryGracefulShutdown*/);
+    }
+
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpServerListen(PRTTCPSERVER pServer, PFNRTTCPSERVE pfnServe, void *pvUser)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pfnServe, VERR_INVALID_POINTER);
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTTCPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    int rc = VERR_INVALID_STATE;
+    if (rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_ACCEPTING, RTTCPSERVERSTATE_CREATED))
+    {
+        Assert(!pServer->pfnServe);
+        Assert(!pServer->pvUser);
+        Assert(pServer->Thread == NIL_RTTHREAD);
+        Assert(pServer->hClientSocket == NIL_RTSOCKET);
+
+        pServer->pfnServe = pfnServe;
+        pServer->pvUser   = pvUser;
+        pServer->Thread   = RTThreadSelf();
+        Assert(pServer->Thread != NIL_RTTHREAD);
+        rc = rtTcpServerListen(pServer);
+    }
+    else
+    {
+        AssertMsgFailed(("enmState=%d\n", pServer->enmState));
+        rc = VERR_INVALID_STATE;
+    }
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return rc;
+}
+
+
+/**
+ * Internal worker common for RTTcpServerListen and the thread created by
+ * RTTcpServerCreate().
+ *
+ * The caller makes sure it has its own memory reference and releases it upon
+ * return.
+ */
+static int rtTcpServerListen(PRTTCPSERVER pServer)
+{
+    /*
+     * Accept connection loop.
+     */
+    for (;;)
+    {
+        /*
+         * Change state, getting an extra reference to the socket so we can
+         * allow others to close it while we're stuck in rtSocketAccept.
+         */
+        RTTCPSERVERSTATE    enmState      = pServer->enmState;
+        RTSOCKET            hServerSocket;
+        ASMAtomicXchgHandle(&pServer->hServerSocket, NIL_RTSOCKET, &hServerSocket);
+        if (hServerSocket != NIL_RTSOCKET)
+        {
+            RTSocketRetain(hServerSocket);
+            ASMAtomicWriteHandle(&pServer->hServerSocket, hServerSocket);
+        }
+        if (    enmState != RTTCPSERVERSTATE_ACCEPTING
+            &&  enmState != RTTCPSERVERSTATE_SERVING)
+        {
+            RTSocketRelease(hServerSocket);
+            return rtTcpServerListenCleanup(pServer);
+        }
+        if (!rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_ACCEPTING, enmState))
+        {
+            RTSocketRelease(hServerSocket);
+            continue;
+        }
+
+        /*
+         * Accept connection.
+         */
+        struct sockaddr_in  RemoteAddr;
+        size_t              cbRemoteAddr = sizeof(RemoteAddr);
+        RTSOCKET            hClientSocket;
+        RT_ZERO(RemoteAddr);
+        int rc = rtSocketAccept(hServerSocket, &hClientSocket, (struct sockaddr *)&RemoteAddr, &cbRemoteAddr);
+        RTSocketRelease(hServerSocket);
+        if (RT_FAILURE(rc))
+        {
+            /* These are typical for what can happen during destruction. */
+            if (   rc == VERR_INVALID_HANDLE
+                || rc == VERR_INVALID_PARAMETER
+                || rc == VERR_NET_NOT_SOCKET)
+                return rtTcpServerListenCleanup(pServer);
+            continue;
+        }
+        RTSocketSetInheritance(hClientSocket, false /*fInheritable*/);
+
+        /*
+         * Run a pfnServe callback.
+         */
+        if (!rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_SERVING, RTTCPSERVERSTATE_ACCEPTING))
+        {
+            rtTcpClose(hClientSocket, "rtTcpServerListen", true /*fTryGracefulShutdown*/);
+            return rtTcpServerListenCleanup(pServer);
+        }
+        RTSocketRetain(hClientSocket);
+        rtTcpAtomicXchgSock(&pServer->hClientSocket, hClientSocket);
+        rc = pServer->pfnServe(hClientSocket, pServer->pvUser);
+        rtTcpServerDestroySocket(&pServer->hClientSocket, "Listener: client (secondary)", true /*fTryGracefulShutdown*/);
+        RTSocketRelease(hClientSocket);
+
+        /*
+         * Stop the server?
+         */
+        if (rc == VERR_TCP_SERVER_STOP)
+        {
+            if (rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_STOPPING, RTTCPSERVERSTATE_SERVING))
+            {
+                /*
+                 * Reset the server socket and change the state to stopped. After that state change
+                 * we cannot safely access the handle so we'll have to return here.
+                 */
+                hServerSocket = rtTcpAtomicXchgSock(&pServer->hServerSocket, NIL_RTSOCKET);
+                rtTcpServerSetState(pServer, RTTCPSERVERSTATE_STOPPED, RTTCPSERVERSTATE_STOPPING);
+                rtTcpClose(hServerSocket, "Listener: server stopped", false /*fTryGracefulShutdown*/);
+            }
+            else
+                rtTcpServerListenCleanup(pServer); /* ignore rc */
+            return rc;
+        }
+    }
+}
+
+
+/**
+ * Clean up after listener.
+ */
+static int rtTcpServerListenCleanup(PRTTCPSERVER pServer)
+{
+    /*
+     * Close the server socket, the client one shouldn't be set.
+     */
+    rtTcpServerDestroySocket(&pServer->hServerSocket, "ListenCleanup", false /*fTryGracefulShutdown*/);
+    Assert(pServer->hClientSocket == NIL_RTSOCKET);
+
+    /*
+     * Figure the return code and make sure the state is OK.
+     */
+    RTTCPSERVERSTATE enmState = pServer->enmState;
+    switch (enmState)
+    {
+        case RTTCPSERVERSTATE_STOPPING:
+        case RTTCPSERVERSTATE_STOPPED:
+            return VERR_TCP_SERVER_SHUTDOWN;
+
+        case RTTCPSERVERSTATE_ACCEPTING:
+            rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_STOPPED, enmState);
+            return VERR_TCP_SERVER_DESTROYED;
+
+        case RTTCPSERVERSTATE_DESTROYING:
+            return VERR_TCP_SERVER_DESTROYED;
+
+        case RTTCPSERVERSTATE_STARTING:
+        case RTTCPSERVERSTATE_SERVING:
+        default:
+            AssertMsgFailedReturn(("pServer=%p enmState=%d\n", pServer, enmState), VERR_INTERNAL_ERROR_4);
+    }
+}
+
+
+RTR3DECL(int) RTTcpServerListen2(PRTTCPSERVER pServer, PRTSOCKET phClientSocket)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(phClientSocket, VERR_INVALID_HANDLE);
+    *phClientSocket = NIL_RTSOCKET;
+    AssertReturn(pServer->u32Magic == RTTCPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    int rc = VERR_INVALID_STATE;
+    for (;;)
+    {
+        /*
+         * Change state, getting an extra reference to the socket so we can
+         * allow others to close it while we're stuck in rtSocketAccept.
+         */
+        RTTCPSERVERSTATE    enmState      = pServer->enmState;
+        RTSOCKET            hServerSocket;
+        ASMAtomicXchgHandle(&pServer->hServerSocket, NIL_RTSOCKET, &hServerSocket);
+        if (hServerSocket != NIL_RTSOCKET)
+        {
+            RTSocketRetain(hServerSocket);
+            ASMAtomicWriteHandle(&pServer->hServerSocket, hServerSocket);
+        }
+        if (    enmState != RTTCPSERVERSTATE_SERVING
+            &&  enmState != RTTCPSERVERSTATE_CREATED)
+        {
+            RTSocketRelease(hServerSocket);
+            return rtTcpServerListenCleanup(pServer);
+        }
+        if (!rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_ACCEPTING, enmState))
+        {
+            RTSocketRelease(hServerSocket);
+            continue;
+        }
+        Assert(!pServer->pfnServe);
+        Assert(!pServer->pvUser);
+        Assert(pServer->Thread == NIL_RTTHREAD);
+        Assert(pServer->hClientSocket == NIL_RTSOCKET);
+
+        /*
+         * Accept connection.
+         */
+        struct sockaddr_in  RemoteAddr;
+        size_t              cbRemoteAddr = sizeof(RemoteAddr);
+        RTSOCKET            hClientSocket;
+        RT_ZERO(RemoteAddr);
+        rc = rtSocketAccept(hServerSocket, &hClientSocket, (struct sockaddr *)&RemoteAddr, &cbRemoteAddr);
+        RTSocketRelease(hServerSocket);
+        if (RT_FAILURE(rc))
+        {
+            if (!rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_CREATED, RTTCPSERVERSTATE_ACCEPTING))
+                rc = rtTcpServerListenCleanup(pServer);
+            if (RT_FAILURE(rc))
+                break;
+            continue;
+        }
+        RTSocketSetInheritance(hClientSocket, false /*fInheritable*/);
+
+        /*
+         * Chance to the 'serving' state and return the socket.
+         */
+        if (rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_SERVING, RTTCPSERVERSTATE_ACCEPTING))
+        {
+            *phClientSocket = hClientSocket;
+            rc = VINF_SUCCESS;
+        }
+        else
+        {
+            rtTcpClose(hClientSocket, "RTTcpServerListen2", true /*fTryGracefulShutdown*/);
+            rc = rtTcpServerListenCleanup(pServer);
+        }
+        break;
+    }
+
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpServerDisconnectClient(PRTTCPSERVER pServer)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTTCPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    int rc = rtTcpServerDestroySocket(&pServer->hClientSocket, "DisconnectClient: client", true /*fTryGracefulShutdown*/);
+
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpServerDisconnectClient2(RTSOCKET hClientSocket)
+{
+    return rtTcpClose(hClientSocket, "RTTcpServerDisconnectClient2", true /*fTryGracefulShutdown*/);
+}
+
+
+RTR3DECL(int) RTTcpServerShutdown(PRTTCPSERVER pServer)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTTCPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    /*
+     * Try change the state to stopping, then replace and destroy the server socket.
+     */
+    for (;;)
+    {
+        RTTCPSERVERSTATE enmState = pServer->enmState;
+        if (    enmState != RTTCPSERVERSTATE_ACCEPTING
+            &&  enmState != RTTCPSERVERSTATE_SERVING)
+        {
+            RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            switch (enmState)
+            {
+                case RTTCPSERVERSTATE_CREATED:
+                case RTTCPSERVERSTATE_STARTING:
+                default:
+                    AssertMsgFailed(("%d\n", enmState));
+                    return VERR_INVALID_STATE;
+
+                case RTTCPSERVERSTATE_STOPPING:
+                case RTTCPSERVERSTATE_STOPPED:
+                    return VINF_SUCCESS;
+
+                case RTTCPSERVERSTATE_DESTROYING:
+                    return VERR_TCP_SERVER_DESTROYED;
+            }
+        }
+        if (rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_STOPPING, enmState))
+        {
+            rtTcpServerDestroySocket(&pServer->hServerSocket, "RTTcpServerShutdown", false /*fTryGracefulShutdown*/);
+            rtTcpServerSetState(pServer, RTTCPSERVERSTATE_STOPPED, RTTCPSERVERSTATE_STOPPING);
+
+            RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            return VINF_SUCCESS;
+        }
+    }
+}
+
+
+RTR3DECL(int) RTTcpServerDestroy(PRTTCPSERVER pServer)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTTCPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE); /* paranoia */
+
+    /*
+     * Move the state along so the listener can figure out what's going on.
+     */
+    for (;;)
+    {
+        bool             fDestroyable;
+        RTTCPSERVERSTATE enmState = pServer->enmState;
+        switch (enmState)
+        {
+            case RTTCPSERVERSTATE_STARTING:
+            case RTTCPSERVERSTATE_ACCEPTING:
+            case RTTCPSERVERSTATE_SERVING:
+            case RTTCPSERVERSTATE_CREATED:
+            case RTTCPSERVERSTATE_STOPPED:
+                fDestroyable = rtTcpServerTrySetState(pServer, RTTCPSERVERSTATE_DESTROYING, enmState);
+                break;
+
+            /* destroyable states */
+            case RTTCPSERVERSTATE_STOPPING:
+                fDestroyable = true;
+                break;
+
+            /*
+             * Everything else means user or internal misbehavior.
+             */
+            default:
+                AssertMsgFailed(("pServer=%p enmState=%d\n", pServer, enmState));
+                RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+                return VERR_INTERNAL_ERROR;
+        }
+        if (fDestroyable)
+            break;
+    }
+
+    /*
+     * Destroy it.
+     */
+    ASMAtomicWriteU32(&pServer->u32Magic, ~RTTCPSERVER_MAGIC);
+    rtTcpServerDestroySocket(&pServer->hServerSocket, "Destroyer: server", false /*fTryGracefulShutdown*/);
+    rtTcpServerDestroySocket(&pServer->hClientSocket, "Destroyer: client", true  /*fTryGracefulShutdown*/);
+
+    /*
+     * Release it.
+     */
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTcpClientConnect(const char *pszAddress, uint32_t uPort, PRTSOCKET pSock)
+{
+    return RTTcpClientConnectEx(pszAddress, uPort, pSock, RT_SOCKETCONNECT_DEFAULT_WAIT, NULL);
+}
+
+
+RTR3DECL(int) RTTcpClientConnectEx(const char *pszAddress, uint32_t uPort, PRTSOCKET pSock,
+                                   RTMSINTERVAL cMillies, PRTTCPCLIENTCONNECTCANCEL volatile *ppCancelCookie)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszAddress, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(ppCancelCookie, VERR_INVALID_POINTER);
+
+    /*
+     * Resolve the address.
+     */
+    RTNETADDR Addr;
+    int rc = RTSocketParseInetAddress(pszAddress, uPort, &Addr);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Create the socket and connect.
+     */
+    RTSOCKET Sock;
+    rc = rtSocketCreate(&Sock, PF_INET, SOCK_STREAM, 0, false /*fInheritable*/);
+    if (RT_SUCCESS(rc))
+    {
+        if (!ppCancelCookie)
+            rc = rtSocketConnect(Sock, &Addr, cMillies);
+        else
+        {
+            RTSocketRetain(Sock);
+            if (ASMAtomicCmpXchgPtr(ppCancelCookie, (PRTTCPCLIENTCONNECTCANCEL)Sock, NULL))
+            {
+                rc = rtSocketConnect(Sock, &Addr, cMillies);
+                if (ASMAtomicCmpXchgPtr(ppCancelCookie, NULL, (PRTTCPCLIENTCONNECTCANCEL)Sock))
+                    RTSocketRelease(Sock);
+                else
+                    rc = VERR_CANCELLED;
+            }
+            else
+            {
+                RTSocketRelease(Sock);
+                rc = VERR_CANCELLED;
+            }
+        }
+        if (RT_SUCCESS(rc))
+        {
+            *pSock = Sock;
+            return VINF_SUCCESS;
+        }
+
+        rtTcpClose(Sock, "RTTcpClientConnect", false /*fTryGracefulShutdown*/);
+    }
+    if (ppCancelCookie)
+        *ppCancelCookie = NULL;
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpClientCancelConnect(PRTTCPCLIENTCONNECTCANCEL volatile *ppCancelCookie)
+{
+    AssertPtrReturn(ppCancelCookie, VERR_INVALID_POINTER);
+
+    RTSOCKET const hSockCancelled = (RTSOCKET)(uintptr_t)0xdead9999;
+
+    AssertCompile(NIL_RTSOCKET == NULL);
+    RTSOCKET hSock = (RTSOCKET)ASMAtomicXchgPtr((void * volatile *)ppCancelCookie, hSockCancelled);
+    if (hSock != NIL_RTSOCKET && hSock != hSockCancelled)
+    {
+        int rc = rtTcpClose(hSock, "RTTcpClientCancelConnect", false /*fTryGracefulShutdown*/);
+        AssertRCReturn(rc, rc);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTcpClientClose(RTSOCKET Sock)
+{
+    return rtTcpClose(Sock, "RTTcpClientClose", true /*fTryGracefulShutdown*/);
+}
+
+
+RTR3DECL(int) RTTcpClientCloseEx(RTSOCKET Sock, bool fGracefulShutdown)
+{
+    return rtTcpClose(Sock, "RTTcpClientCloseEx", fGracefulShutdown);
+}
+
+
+#ifdef FIX_FOR_3_2
+/**
+ * Changes the blocking mode of the socket.
+ *
+ * @returns 0 on success, -1 on failure.
+ * @param   hSocket             The socket to work on.
+ * @param   fBlocking           The desired mode of operation.
+ */
+static int rtTcpSetBlockingMode(RTHCUINTPTR hSocket, bool fBlocking)
+{
+    int     rc        = VINF_SUCCESS;
+#ifdef RT_OS_WINDOWS
+    u_long  uBlocking = fBlocking ? 0 : 1;
+    if (ioctlsocket(hSocket, FIONBIO, &uBlocking))
+        return -1;
+
+#else
+    int     fFlags    = fcntl(hSocket, F_GETFL, 0);
+    if (fFlags == -1)
+        return -1;
+
+    if (fBlocking)
+        fFlags &= ~O_NONBLOCK;
+    else
+        fFlags |= O_NONBLOCK;
+    if (fcntl(hSocket, F_SETFL, fFlags) == -1)
+       return -1;
+#endif
+
+    return 0;
+}
+#endif
+
+
+/**
+ * Internal close function which does all the proper bitching.
+ */
+static int rtTcpClose(RTSOCKET Sock, const char *pszMsg, bool fTryGracefulShutdown)
+{
+    NOREF(pszMsg); /** @todo drop this parameter? */
+
+    /* ignore nil handles. */
+    if (Sock == NIL_RTSOCKET)
+        return VINF_SUCCESS;
+
+    /*
+     * Try to gracefully shut it down.
+     */
+    int rc;
+    if (fTryGracefulShutdown)
+    {
+        rc = RTSocketShutdown(Sock, false /*fRead*/, true /*fWrite*/);
+#ifdef FIX_FOR_3_2
+        RTHCUINTPTR hNative = RTSocketToNative(Sock);
+        if (RT_SUCCESS(rc) && rtTcpSetBlockingMode(hNative, false /*fBlocking*/) == 0)
+#else
+        if (RT_SUCCESS(rc))
+#endif
+        {
+
+            size_t      cbReceived = 0;
+            uint64_t    u64Start   = RTTimeMilliTS();
+            while (   cbReceived < _1G
+                   && RTTimeMilliTS() - u64Start < 30000)
+            {
+#ifdef FIX_FOR_3_2
+                fd_set FdSetR;
+                FD_ZERO(&FdSetR);
+                FD_SET(hNative, &FdSetR);
+
+                fd_set FdSetE;
+                FD_ZERO(&FdSetE);
+                FD_SET(hNative, &FdSetE);
+
+                struct timeval TvTimeout;
+                TvTimeout.tv_sec  = 1;
+                TvTimeout.tv_usec = 0;
+                rc = select(hNative + 1, &FdSetR, NULL, &FdSetE, &TvTimeout);
+                if (rc == 0)
+                    continue;
+                if (rc < 0)
+                    break;
+                if (FD_ISSET(hNative, &FdSetE))
+                    break;
+#else
+                uint32_t fEvents;
+                rc = RTSocketSelectOneEx(Sock, RTSOCKET_EVT_READ | RTSOCKET_EVT_ERROR, &fEvents, 1000);
+                if (rc == VERR_TIMEOUT)
+                    continue;
+                if (RT_FAILURE(rc))
+                    break;
+                if (fEvents & RTSOCKET_EVT_ERROR)
+                    break;
+#endif
+
+                char abBitBucket[16*_1K];
+#ifdef FIX_FOR_3_2
+                ssize_t cbRead = recv(hNative, &abBitBucket[0], sizeof(abBitBucket), MSG_NOSIGNAL);
+                if (cbRead == 0)
+                    break; /* orderly shutdown in progress */
+                if (cbRead < 0 && errno != EAGAIN)
+                    break; /* some kind of error, never mind which... */
+#else
+                size_t cbRead;
+                rc = RTSocketReadNB(Sock, &abBitBucket[0], sizeof(abBitBucket), &cbRead);
+                if (RT_FAILURE(rc))
+                    break; /* some kind of error, never mind which... */
+                if (rc != VINF_TRY_AGAIN && !cbRead)
+                    break; /* orderly shutdown in progress */
+#endif
+
+                cbReceived += cbRead;
+            }
+        }
+    }
+
+    /*
+     * Close the socket handle (drops our reference to it).
+     */
+    return RTSocketClose(Sock);
+}
+
+
+RTR3DECL(int) RTTcpCreatePair(PRTSOCKET phServer, PRTSOCKET phClient, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phServer, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(phClient, VERR_INVALID_PARAMETER);
+    AssertReturn(!fFlags, VERR_INVALID_PARAMETER);
+
+    /*
+     * Do the job.
+     */
+    return rtSocketCreateTcpPair(phServer, phClient);
+}
+
+
+RTR3DECL(int) RTTcpRead(RTSOCKET Sock, void *pvBuffer, size_t cbBuffer, size_t *pcbRead)
+{
+    return RTSocketRead(Sock, pvBuffer, cbBuffer, pcbRead);
+}
+
+
+RTR3DECL(int)  RTTcpWrite(RTSOCKET Sock, const void *pvBuffer, size_t cbBuffer)
+{
+    return RTSocketWrite(Sock, pvBuffer, cbBuffer);
+}
+
+
+RTR3DECL(int)  RTTcpFlush(RTSOCKET Sock)
+{
+    int fFlag = 1;
+    int rc = rtSocketSetOpt(Sock, IPPROTO_TCP, TCP_NODELAY, &fFlag, sizeof(fFlag));
+    if (RT_SUCCESS(rc))
+    {
+        fFlag = 0;
+        rc = rtSocketSetOpt(Sock, IPPROTO_TCP, TCP_NODELAY, &fFlag, sizeof(fFlag));
+    }
+    return rc;
+}
+
+
+RTR3DECL(int)  RTTcpSetSendCoalescing(RTSOCKET Sock, bool fEnable)
+{
+    int fFlag = fEnable ? 0 : 1;
+    return rtSocketSetOpt(Sock, IPPROTO_TCP, TCP_NODELAY, &fFlag, sizeof(fFlag));
+}
+
+
+RTR3DECL(int)  RTTcpSetBufferSize(RTSOCKET hSocket, uint32_t cbSize)
+{
+    int cbIntSize = (int)cbSize;
+    AssertReturn(cbIntSize >= 0, VERR_OUT_OF_RANGE);
+    int rc = rtSocketSetOpt(hSocket, SOL_SOCKET, SO_SNDBUF, &cbIntSize, sizeof(cbIntSize));
+    if (RT_SUCCESS(rc))
+        rc = rtSocketSetOpt(hSocket, SOL_SOCKET, SO_RCVBUF, &cbIntSize, sizeof(cbIntSize));
+    return rc;
+}
+
+
+RTR3DECL(int)  RTTcpSelectOne(RTSOCKET Sock, RTMSINTERVAL cMillies)
+{
+    return RTSocketSelectOne(Sock, cMillies);
+}
+
+
+RTR3DECL(int)  RTTcpSelectOneEx(RTSOCKET Sock, uint32_t fEvents, uint32_t *pfEvents,
+                                RTMSINTERVAL cMillies)
+{
+    return RTSocketSelectOneEx(Sock, fEvents, pfEvents, cMillies);
+}
+
+
+RTR3DECL(int) RTTcpGetLocalAddress(RTSOCKET Sock, PRTNETADDR pAddr)
+{
+    return RTSocketGetLocalAddress(Sock, pAddr);
+}
+
+
+RTR3DECL(int) RTTcpGetPeerAddress(RTSOCKET Sock, PRTNETADDR pAddr)
+{
+    return RTSocketGetPeerAddress(Sock, pAddr);
+}
+
+
+RTR3DECL(int)  RTTcpSgWrite(RTSOCKET Sock, PCRTSGBUF pSgBuf)
+{
+    return RTSocketSgWrite(Sock, pSgBuf);
+}
+
+
+RTR3DECL(int) RTTcpSgWriteL(RTSOCKET hSocket, size_t cSegs, ...)
+{
+    va_list va;
+    va_start(va, cSegs);
+    int rc = RTSocketSgWriteLV(hSocket, cSegs, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpSgWriteLV(RTSOCKET hSocket, size_t cSegs, va_list va)
+{
+    return RTSocketSgWriteLV(hSocket, cSegs, va);
+}
+
+
+RTR3DECL(int) RTTcpReadNB(RTSOCKET Sock, void *pvBuffer, size_t cbBuffer, size_t *pcbRead)
+{
+    return RTSocketReadNB(Sock, pvBuffer, cbBuffer, pcbRead);
+}
+
+
+RTR3DECL(int) RTTcpWriteNB(RTSOCKET Sock, const void *pvBuffer, size_t cbBuffer, size_t *pcbWritten)
+{
+    return RTSocketWriteNB(Sock, pvBuffer, cbBuffer, pcbWritten);
+}
+
+
+RTR3DECL(int)  RTTcpSgWriteNB(RTSOCKET Sock, PCRTSGBUF pSgBuf, size_t *pcbWritten)
+{
+    return RTSocketSgWriteNB(Sock, pSgBuf, pcbWritten);
+}
+
+
+RTR3DECL(int) RTTcpSgWriteLNB(RTSOCKET hSocket, size_t cSegs, size_t *pcbWritten, ...)
+{
+    va_list va;
+    va_start(va, pcbWritten);
+    int rc = RTSocketSgWriteLVNB(hSocket, cSegs, pcbWritten, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTcpSgWriteLVNB(RTSOCKET hSocket, size_t cSegs, size_t *pcbWritten, va_list va)
+{
+    return RTSocketSgWriteLVNB(hSocket, cSegs, pcbWritten, va);
+}
+
diff --git a/src/VBox/Runtime/r3/test.cpp b/src/VBox/Runtime/r3/test.cpp
new file mode 100644
index 00000000..a0b90870
--- /dev/null
+++ b/src/VBox/Runtime/r3/test.cpp
@@ -0,0 +1,1662 @@
+/* $Id: test.cpp $ */
+/** @file
+ * IPRT - Testcase Framework.
+ */
+
+/*
+ * Copyright (C) 2009-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/test.h>
+
+#include <iprt/asm.h>
+#include <iprt/critsect.h>
+#include <iprt/env.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/initterm.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/param.h>
+#include <iprt/pipe.h>
+#include <iprt/string.h>
+#include <iprt/stream.h>
+
+#include "internal/magics.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Guarded memory allocation record.
+ */
+typedef struct RTTESTGUARDEDMEM
+{
+    /** Pointer to the next record. */
+    struct RTTESTGUARDEDMEM *pNext;
+    /** The address we return to the user. */
+    void           *pvUser;
+    /** The base address of the allocation. */
+    void           *pvAlloc;
+    /** The size of the allocation. */
+    size_t          cbAlloc;
+    /** Guards. */
+    struct
+    {
+        /** The guard address. */
+        void       *pv;
+        /** The guard size. */
+        size_t      cb;
+    }               aGuards[2];
+} RTTESTGUARDEDMEM;
+/** Pointer to an guarded memory allocation. */
+typedef RTTESTGUARDEDMEM *PRTTESTGUARDEDMEM;
+
+/**
+ * Test instance structure.
+ */
+typedef struct RTTESTINT
+{
+    /** Magic. */
+    uint32_t            u32Magic;
+    /** The number of errors. */
+    volatile uint32_t   cErrors;
+    /** The test name. */
+    const char         *pszTest;
+    /** The length of the test name.  */
+    size_t              cchTest;
+    /** The size of a guard. Multiple of PAGE_SIZE. */
+    uint32_t            cbGuard;
+    /** The verbosity level. */
+    RTTESTLVL           enmMaxLevel;
+    /** The creation flags. */
+    uint32_t            fFlags;
+
+
+    /** Critical section serializing output. */
+    RTCRITSECT          OutputLock;
+    /** The output stream. */
+    PRTSTREAM           pOutStrm;
+    /** Whether we're currently at a newline. */
+    bool                fNewLine;
+
+
+    /** Critical section serializing access to the members following it. */
+    RTCRITSECT          Lock;
+
+    /** The list of guarded memory allocations. */
+    PRTTESTGUARDEDMEM   pGuardedMem;
+
+    /** The current sub-test. */
+    const char         *pszSubTest;
+    /** The length of the sub-test name. */
+    size_t              cchSubTest;
+    /** Whether the current subtest should figure as 'SKIPPED'. */
+    bool                fSubTestSkipped;
+    /** Whether we've reported the sub-test result or not. */
+    bool                fSubTestReported;
+    /** The start error count of the current subtest. */
+    uint32_t            cSubTestAtErrors;
+
+    /** The number of sub tests. */
+    uint32_t            cSubTests;
+    /** The number of sub tests that failed. */
+    uint32_t            cSubTestsFailed;
+
+    /** Error context message. */
+    char               *pszErrCtx;
+
+    /** Set if XML output is enabled. */
+    bool                fXmlEnabled;
+    /** Set if we omit the top level test in the XML report. */
+    bool                fXmlOmitTopTest;
+    /** Set if we've reported the top test (for RTTEST_C_XML_DELAY_TOP_TEST). */
+    bool                fXmlTopTestDone;
+    enum {
+        kXmlPos_ValueStart,
+        kXmlPos_Value,
+        kXmlPos_ElementEnd
+    }                   eXmlState;
+    /** Test pipe for the XML output stream going to the server. */
+    RTPIPE              hXmlPipe;
+    /** File where the XML output stream might be directed.  */
+    RTFILE              hXmlFile;
+    /** The number of XML elements on the stack. */
+    size_t              cXmlElements;
+    /** XML element stack. */
+    const char         *apszXmlElements[10];
+
+    /** Number of times assertions has been disabled and quieted. */
+    uint32_t volatile   cAssertionsDisabledAndQuieted;
+    /** Saved RTAssertSetQuiet return code. */
+    bool                fAssertSavedQuiet;
+    /** Saved RTAssertSetMayPanic return code. */
+    bool                fAssertSavedMayPanic;
+} RTTESTINT;
+/** Pointer to a test instance. */
+typedef RTTESTINT *PRTTESTINT;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Validate a test instance. */
+#define RTTEST_VALID_RETURN(pTest)  \
+    do { \
+        AssertPtrReturn(pTest, VERR_INVALID_HANDLE); \
+        AssertReturn(pTest->u32Magic == RTTESTINT_MAGIC, VERR_INVALID_HANDLE); \
+    } while (0)
+
+/** Gets and validates a test instance.
+ * If the handle is nil, we will try retrieve it from the test TLS entry.
+ */
+#define RTTEST_GET_VALID_RETURN(pTest)  \
+    do { \
+        if (pTest == NIL_RTTEST) \
+            pTest = (PRTTESTINT)RTTlsGet(g_iTestTls); \
+        AssertPtrReturn(pTest, VERR_INVALID_HANDLE); \
+        AssertReturn(pTest->u32Magic == RTTESTINT_MAGIC, VERR_INVALID_MAGIC); \
+    } while (0)
+
+
+/** Gets and validates a test instance.
+ * If the handle is nil, we will try retrieve it from the test TLS entry.
+ */
+#define RTTEST_GET_VALID_RETURN_RC(pTest, rc)  \
+    do { \
+        if (pTest == NIL_RTTEST) \
+            pTest = (PRTTESTINT)RTTlsGet(g_iTestTls); \
+        AssertPtrReturn(pTest, (rc)); \
+        AssertReturn(pTest->u32Magic == RTTESTINT_MAGIC, (rc)); \
+    } while (0)
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static void rtTestGuardedFreeOne(PRTTESTGUARDEDMEM pMem);
+static int  rtTestPrintf(PRTTESTINT pTest, const char *pszFormat, ...);
+static void rtTestXmlStart(PRTTESTINT pTest, const char *pszTest);
+static void rtTestXmlElemV(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, va_list va);
+static void rtTestXmlElem(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, ...);
+static void rtTestXmlElemStartV(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, va_list va);
+static void rtTestXmlElemStart(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, ...);
+static void rtTestXmlElemEnd(PRTTESTINT pTest, const char *pszTag);
+static void rtTestXmlEnd(PRTTESTINT pTest);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** For serializing TLS init. */
+static RTONCE   g_TestInitOnce = RTONCE_INITIALIZER;
+/** Our TLS entry. */
+static RTTLS    g_iTestTls = NIL_RTTLS;
+
+
+
+/**
+ * Init TLS index once.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser      Ignored.
+ */
+static DECLCALLBACK(int32_t) rtTestInitOnce(void *pvUser)
+{
+    NOREF(pvUser);
+    return RTTlsAllocEx(&g_iTestTls, NULL);
+}
+
+
+RTR3DECL(int) RTTestCreateEx(const char *pszTest, uint32_t fFlags, RTTESTLVL enmMaxLevel,
+                             RTHCINTPTR iNativeTestPipe, const char *pszXmlFile, PRTTEST phTest)
+{
+    AssertReturn(!(fFlags & ~RTTEST_C_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtrNull(phTest);
+    AssertPtrNull(pszXmlFile);
+    /* RTTESTLVL_INVALID is valid! */
+    AssertReturn(enmMaxLevel >= RTTESTLVL_INVALID && enmMaxLevel < RTTESTLVL_END, VERR_INVALID_PARAMETER);
+
+    /*
+     * Global init.
+     */
+    int rc = RTOnce(&g_TestInitOnce, rtTestInitOnce, NULL);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Create the instance.
+     */
+    PRTTESTINT pTest = (PRTTESTINT)RTMemAllocZ(sizeof(*pTest));
+    if (!pTest)
+        return VERR_NO_MEMORY;
+    pTest->u32Magic         = RTTESTINT_MAGIC;
+    pTest->pszTest          = RTStrDup(pszTest);
+    pTest->cchTest          = strlen(pszTest);
+    pTest->cbGuard          = PAGE_SIZE * 7;
+    pTest->enmMaxLevel      = enmMaxLevel == RTTESTLVL_INVALID ? RTTESTLVL_INFO : enmMaxLevel;
+    pTest->fFlags           = fFlags;
+
+    pTest->pOutStrm         = g_pStdOut;
+    pTest->fNewLine         = true;
+
+    pTest->pGuardedMem      = NULL;
+
+    pTest->pszSubTest       = NULL;
+    pTest->cchSubTest       = 0;
+    pTest->fSubTestSkipped  = false;
+    pTest->fSubTestReported = true;
+    pTest->cSubTestAtErrors = 0;
+    pTest->cSubTests        = 0;
+    pTest->cSubTestsFailed  = 0;
+
+    pTest->fXmlEnabled      = false;
+    pTest->fXmlTopTestDone  = false;
+    pTest->eXmlState        = RTTESTINT::kXmlPos_ElementEnd;
+    pTest->hXmlPipe         = NIL_RTPIPE;
+    pTest->hXmlFile         = NIL_RTFILE;
+    pTest->cXmlElements     = 0;
+    pTest->cAssertionsDisabledAndQuieted = 0;
+    pTest->fAssertSavedMayPanic          = true;
+    pTest->fAssertSavedQuiet             = false;
+
+    rc = RTCritSectInit(&pTest->Lock);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTCritSectInit(&pTest->OutputLock);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Associate it with our TLS entry unless there is already
+             * an instance there.
+             */
+            if (   !(fFlags & RTTEST_C_NO_TLS)
+                && !RTTlsGet(g_iTestTls))
+                rc = RTTlsSet(g_iTestTls, pTest);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Output level override?
+                 */
+                char szEnvVal[RTPATH_MAX];
+                if ((fFlags & RTTEST_C_USE_ENV) && enmMaxLevel == RTTESTLVL_INVALID)
+                {
+                    rc = RTEnvGetEx(RTENV_DEFAULT, "IPRT_TEST_MAX_LEVEL", szEnvVal, sizeof(szEnvVal), NULL);
+                    if (RT_SUCCESS(rc))
+                    {
+                        char *pszMaxLevel = RTStrStrip(szEnvVal);
+                        if (!strcmp(pszMaxLevel, "all"))
+                            pTest->enmMaxLevel = RTTESTLVL_DEBUG;
+                        if (!strcmp(pszMaxLevel, "quiet"))
+                            pTest->enmMaxLevel = RTTESTLVL_FAILURE;
+                        else if (!strcmp(pszMaxLevel, "debug"))
+                            pTest->enmMaxLevel = RTTESTLVL_DEBUG;
+                        else if (!strcmp(pszMaxLevel, "info"))
+                            pTest->enmMaxLevel = RTTESTLVL_INFO;
+                        else if (!strcmp(pszMaxLevel, "sub_test"))
+                            pTest->enmMaxLevel = RTTESTLVL_SUB_TEST;
+                        else if (!strcmp(pszMaxLevel, "failure"))
+                            pTest->enmMaxLevel = RTTESTLVL_FAILURE;
+                    }
+                    else if (rc != VERR_ENV_VAR_NOT_FOUND)
+                        RTStrmPrintf(g_pStdErr, "%s: test pipe error: RTEnvGetEx(IPRT_TEST_MAX_LEVEL) -> %Rrc\n", pszTest, rc);
+                }
+
+                /*
+                 * Any test driver we are connected or should connect to?
+                 */
+                if (!(fFlags & RTTEST_C_NO_XML_REPORTING_PIPE))
+                {
+                    if (   (fFlags & RTTEST_C_USE_ENV)
+                        && iNativeTestPipe == -1)
+                    {
+                        rc = RTEnvGetEx(RTENV_DEFAULT, "IPRT_TEST_PIPE", szEnvVal, sizeof(szEnvVal), NULL);
+                        if (RT_SUCCESS(rc))
+                        {
+#if ARCH_BITS == 64
+                            rc = RTStrToInt64Full(szEnvVal, 0, &iNativeTestPipe);
+#else
+                            rc = RTStrToInt32Full(szEnvVal, 0, &iNativeTestPipe);
+#endif
+                            if (RT_FAILURE(rc))
+                            {
+                                RTStrmPrintf(g_pStdErr, "%s: test pipe error: RTStrToInt32Full(\"%s\") -> %Rrc\n",
+                                             pszTest, szEnvVal, rc);
+                                iNativeTestPipe = -1;
+                            }
+                        }
+                        else if (rc != VERR_ENV_VAR_NOT_FOUND)
+                            RTStrmPrintf(g_pStdErr, "%s: test pipe error: RTEnvGetEx(IPRT_TEST_PIPE) -> %Rrc\n", pszTest, rc);
+                    }
+                    if (iNativeTestPipe != -1)
+                    {
+                        rc = RTPipeFromNative(&pTest->hXmlPipe, iNativeTestPipe, RTPIPE_N_WRITE);
+                        if (RT_SUCCESS(rc))
+                            pTest->fXmlEnabled = true;
+                        else
+                        {
+                            RTStrmPrintf(g_pStdErr, "%s: test pipe error: RTPipeFromNative(,%p,WRITE) -> %Rrc\n",
+                                         pszTest, iNativeTestPipe, rc);
+                            pTest->hXmlPipe = NIL_RTPIPE;
+                        }
+                    }
+                }
+
+                /*
+                 * Any test file we should write the test report to?
+                 */
+                if (!(fFlags & RTTEST_C_NO_XML_REPORTING_FILE))
+                {
+                    if ((fFlags & RTTEST_C_USE_ENV) && pszXmlFile == NULL)
+                    {
+                        rc = RTEnvGetEx(RTENV_DEFAULT, "IPRT_TEST_FILE", szEnvVal, sizeof(szEnvVal), NULL);
+                        if (RT_SUCCESS(rc))
+                            pszXmlFile = szEnvVal;
+                        else if (rc != VERR_ENV_VAR_NOT_FOUND)
+                            RTStrmPrintf(g_pStdErr, "%s: test file error: RTEnvGetEx(IPRT_TEST_MAX_LEVEL) -> %Rrc\n", pszTest, rc);
+                    }
+                    if (pszXmlFile && *pszXmlFile)
+                    {
+                        rc = RTFileOpen(&pTest->hXmlFile, pszXmlFile,
+                                        RTFILE_O_WRITE | RTFILE_O_DENY_WRITE | RTFILE_O_OPEN_CREATE | RTFILE_O_TRUNCATE);
+                        if (RT_SUCCESS(rc))
+                            pTest->fXmlEnabled = true;
+                        else
+                        {
+                            RTStrmPrintf(g_pStdErr, "%s: test file error: RTFileOpen(,\"%s\",) -> %Rrc\n",
+                                         pszTest, pszXmlFile, rc);
+                            pTest->hXmlFile = NIL_RTFILE;
+                        }
+                    }
+                }
+
+                /*
+                 * What do we report in the XML stream/file.?
+                 */
+                pTest->fXmlOmitTopTest = (fFlags & RTTEST_C_XML_OMIT_TOP_TEST)
+                                      || (   (fFlags & RTTEST_C_USE_ENV)
+                                          && RTEnvExistEx(RTENV_DEFAULT, "IPRT_TEST_OMIT_TOP_TEST"));
+
+                /*
+                 * Tell the test driver that we're up to.
+                 */
+                rtTestXmlStart(pTest, pszTest);
+
+                *phTest = pTest;
+                return VINF_SUCCESS;
+            }
+
+            /* bail out. */
+            RTCritSectDelete(&pTest->OutputLock);
+        }
+        RTCritSectDelete(&pTest->Lock);
+    }
+    pTest->u32Magic = 0;
+    RTStrFree((char *)pTest->pszTest);
+    RTMemFree(pTest);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestCreate(const char *pszTest, PRTTEST phTest)
+{
+    return RTTestCreateEx(pszTest, RTTEST_C_USE_ENV, RTTESTLVL_INVALID, -1 /*iNativeTestPipe*/, NULL /*pszXmlFile*/, phTest);
+}
+
+
+RTR3DECL(int) RTTestCreateChild(const char *pszTest, PRTTEST phTest)
+{
+    return RTTestCreateEx(pszTest, RTTEST_C_USE_ENV | RTTEST_C_NO_XML_REPORTING,
+                          RTTESTLVL_INVALID, -1 /*iNativeTestPipe*/, NULL /*pszXmlFile*/, phTest);
+}
+
+
+RTR3DECL(RTEXITCODE) RTTestInitAndCreate(const char *pszTest, PRTTEST phTest)
+{
+    int rc = RTR3InitExeNoArguments(0);
+    if (RT_FAILURE(rc))
+    {
+        RTStrmPrintf(g_pStdErr, "%s: fatal error: RTR3InitExeNoArguments failed with rc=%Rrc\n", pszTest, rc);
+        return RTEXITCODE_INIT;
+    }
+
+    rc = RTTestCreate(pszTest, phTest);
+    if (RT_FAILURE(rc))
+    {
+        RTStrmPrintf(g_pStdErr, "%s: fatal error: RTTestCreate failed with rc=%Rrc\n", pszTest, rc);
+        return RTEXITCODE_INIT;
+    }
+    return RTEXITCODE_SUCCESS;
+}
+
+
+RTR3DECL(RTEXITCODE) RTTestInitExAndCreate(int cArgs, char ***ppapszArgs, uint32_t fRtInit, const char *pszTest, PRTTEST phTest)
+{
+    int rc;
+    if (cArgs <= 0 && ppapszArgs == NULL)
+        rc = RTR3InitExeNoArguments(fRtInit);
+    else
+        rc = RTR3InitExe(cArgs, ppapszArgs, fRtInit);
+    if (RT_FAILURE(rc))
+    {
+        RTStrmPrintf(g_pStdErr, "%s: fatal error: RTR3InitExe(,,%#x) failed with rc=%Rrc\n", pszTest, fRtInit, rc);
+        return RTEXITCODE_INIT;
+    }
+
+    rc = RTTestCreate(pszTest, phTest);
+    if (RT_FAILURE(rc))
+    {
+        RTStrmPrintf(g_pStdErr, "%s: fatal error: RTTestCreate failed with rc=%Rrc\n", pszTest, rc);
+        return RTEXITCODE_INIT;
+    }
+    return RTEXITCODE_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestDestroy(RTTEST hTest)
+{
+    /*
+     * Validate
+     */
+    if (hTest == NIL_RTTEST)
+        return VINF_SUCCESS;
+    RTTESTINT *pTest = hTest;
+    RTTEST_VALID_RETURN(pTest);
+
+    /*
+     * Make sure we end with a new line and have finished up the XML.
+     */
+    if (!pTest->fNewLine)
+        rtTestPrintf(pTest, "\n");
+    rtTestXmlEnd(pTest);
+
+    /*
+     * Clean up.
+     */
+    if ((RTTESTINT *)RTTlsGet(g_iTestTls) == pTest)
+        RTTlsSet(g_iTestTls, NULL);
+
+    ASMAtomicWriteU32(&pTest->u32Magic, ~RTTESTINT_MAGIC);
+    RTCritSectDelete(&pTest->Lock);
+    RTCritSectDelete(&pTest->OutputLock);
+
+    /* free guarded memory. */
+    PRTTESTGUARDEDMEM pMem = pTest->pGuardedMem;
+    pTest->pGuardedMem = NULL;
+    while (pMem)
+    {
+        PRTTESTGUARDEDMEM pFree = pMem;
+        pMem = pMem->pNext;
+        rtTestGuardedFreeOne(pFree);
+    }
+
+    RTStrFree((char *)pTest->pszSubTest);
+    pTest->pszSubTest = NULL;
+    RTStrFree((char *)pTest->pszTest);
+    pTest->pszTest = NULL;
+    RTStrFree(pTest->pszErrCtx);
+    pTest->pszErrCtx = NULL;
+    RTMemFree(pTest);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestSetDefault(RTTEST hNewDefaultTest, PRTTEST phOldTest)
+{
+    if (phOldTest)
+        *phOldTest = (RTTEST)RTTlsGet(g_iTestTls);
+    return RTTlsSet(g_iTestTls, hNewDefaultTest);
+}
+
+
+RTR3DECL(int) RTTestChangeName(RTTEST hTest, const char *pszName)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertReturn(*pszName, VERR_INVALID_PARAMETER);
+
+    size_t cchName = strlen(pszName);
+    AssertReturn(cchName < 128, VERR_INVALID_PARAMETER);
+    char *pszDupName = RTStrDup(pszName);
+    if (!pszDupName)
+        return VERR_NO_STR_MEMORY;
+
+    RTCritSectEnter(&pTest->Lock);
+    RTCritSectEnter(&pTest->OutputLock);
+
+    char *pszOldName = (char *)pTest->pszTest;
+    pTest->pszTest = pszDupName;
+    pTest->cchTest = cchName;
+
+    RTCritSectLeave(&pTest->OutputLock);
+    RTCritSectLeave(&pTest->Lock);
+
+    RTStrFree(pszOldName);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestGuardedAlloc(RTTEST hTest, size_t cb, uint32_t cbAlign, bool fHead, void **ppvUser)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+    if (cbAlign == 0)
+        cbAlign = 1;
+    AssertReturn(cbAlign <= PAGE_SIZE, VERR_INVALID_PARAMETER);
+    AssertReturn(cbAlign == (UINT32_C(1) << (ASMBitFirstSetU32(cbAlign) - 1)), VERR_INVALID_PARAMETER);
+
+    /*
+     * Allocate the record and block and initialize them.
+     */
+    int                 rc = VERR_NO_MEMORY;
+    PRTTESTGUARDEDMEM   pMem = (PRTTESTGUARDEDMEM)RTMemAlloc(sizeof(*pMem));
+    if (RT_LIKELY(pMem))
+    {
+        size_t const    cbAligned = RT_ALIGN_Z(cb, PAGE_SIZE);
+        pMem->aGuards[0].cb = pMem->aGuards[1].cb = pTest->cbGuard;
+        pMem->cbAlloc       = pMem->aGuards[0].cb + pMem->aGuards[1].cb + cbAligned;
+        pMem->pvAlloc       = RTMemPageAlloc(pMem->cbAlloc);
+        if (pMem->pvAlloc)
+        {
+            pMem->aGuards[0].pv = pMem->pvAlloc;
+            pMem->pvUser        = (uint8_t *)pMem->pvAlloc + pMem->aGuards[0].cb;
+            pMem->aGuards[1].pv = (uint8_t *)pMem->pvUser + cbAligned;
+            if (!fHead)
+            {
+                size_t off = cb & PAGE_OFFSET_MASK;
+                if (off)
+                {
+                    off = PAGE_SIZE - RT_ALIGN_Z(off, cbAlign);
+                    pMem->pvUser = (uint8_t *)pMem->pvUser + off;
+                }
+            }
+
+            /*
+             * Set up the guards and link the record.
+             */
+            ASMMemFill32(pMem->aGuards[0].pv, pMem->aGuards[0].cb, 0xdeadbeef);
+            ASMMemFill32(pMem->aGuards[1].pv, pMem->aGuards[1].cb, 0xdeadbeef);
+            rc = RTMemProtect(pMem->aGuards[0].pv, pMem->aGuards[0].cb, RTMEM_PROT_NONE);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTMemProtect(pMem->aGuards[1].pv, pMem->aGuards[1].cb, RTMEM_PROT_NONE);
+                if (RT_SUCCESS(rc))
+                {
+                    *ppvUser = pMem->pvUser;
+
+                    RTCritSectEnter(&pTest->Lock);
+                    pMem->pNext = pTest->pGuardedMem;
+                    pTest->pGuardedMem = pMem;
+                    RTCritSectLeave(&pTest->Lock);
+
+                    return VINF_SUCCESS;
+                }
+
+                RTMemProtect(pMem->aGuards[0].pv, pMem->aGuards[0].cb, RTMEM_PROT_WRITE | RTMEM_PROT_READ);
+            }
+
+            RTMemPageFree(pMem->pvAlloc, pMem->cbAlloc);
+        }
+        RTMemFree(pMem);
+    }
+    return rc;
+}
+
+
+RTR3DECL(void *) RTTestGuardedAllocTail(RTTEST hTest, size_t cb)
+{
+    void *pvUser;
+    int rc = RTTestGuardedAlloc(hTest, cb, 1 /* cbAlign */, false /* fHead */, &pvUser);
+    if (RT_SUCCESS(rc))
+        return pvUser;
+    return NULL;
+}
+
+
+RTR3DECL(void *) RTTestGuardedAllocHead(RTTEST hTest, size_t cb)
+{
+    void *pvUser;
+    int rc = RTTestGuardedAlloc(hTest, cb, 1 /* cbAlign */, true /* fHead */, &pvUser);
+    if (RT_SUCCESS(rc))
+        return pvUser;
+    return NULL;
+}
+
+
+/**
+ * Frees one block of guarded memory.
+ *
+ * The caller is responsible for unlinking it.
+ *
+ * @param   pMem        The memory record.
+ */
+static void rtTestGuardedFreeOne(PRTTESTGUARDEDMEM pMem)
+{
+    int rc;
+    rc = RTMemProtect(pMem->aGuards[0].pv, pMem->aGuards[0].cb, RTMEM_PROT_WRITE | RTMEM_PROT_READ); AssertRC(rc);
+    rc = RTMemProtect(pMem->aGuards[1].pv, pMem->aGuards[1].cb, RTMEM_PROT_WRITE | RTMEM_PROT_READ); AssertRC(rc);
+    RTMemPageFree(pMem->pvAlloc, pMem->cbAlloc);
+    RTMemFree(pMem);
+}
+
+
+RTR3DECL(int) RTTestGuardedFree(RTTEST hTest, void *pv)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+    if (!pv)
+        return VINF_SUCCESS;
+
+    /*
+     * Find it.
+     */
+    int                 rc = VERR_INVALID_POINTER;
+    PRTTESTGUARDEDMEM   pPrev = NULL;
+
+    RTCritSectEnter(&pTest->Lock);
+    for (PRTTESTGUARDEDMEM pMem = pTest->pGuardedMem; pMem; pMem = pMem->pNext)
+    {
+        if (pMem->pvUser == pv)
+        {
+            if (pPrev)
+                pPrev->pNext = pMem->pNext;
+            else
+                pTest->pGuardedMem = pMem->pNext;
+            rtTestGuardedFreeOne(pMem);
+            rc = VINF_SUCCESS;
+            break;
+        }
+        pPrev = pMem;
+    }
+    RTCritSectLeave(&pTest->Lock);
+
+    return rc;
+}
+
+
+/**
+ * Outputs the formatted XML.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszFormat           The format string.
+ * @param   va                  The format arguments.
+ */
+static void rtTestXmlOutputV(PRTTESTINT pTest, const char *pszFormat, va_list va)
+{
+    if (pTest->fXmlEnabled)
+    {
+        char *pszStr;
+        ssize_t cchStr = RTStrAPrintfV(&pszStr, pszFormat, va);
+        if (pszStr)
+        {
+            if (pTest->hXmlPipe != NIL_RTPIPE)
+                RTPipeWriteBlocking(pTest->hXmlPipe, pszStr, cchStr,  NULL);
+            if (pTest->hXmlFile != NIL_RTFILE)
+                RTFileWrite(pTest->hXmlFile, pszStr, cchStr, NULL);
+            RTStrFree(pszStr);
+        }
+    }
+}
+
+
+/**
+ * Outputs the formatted XML.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszFormat           The format string.
+ * @param   ...                 The format arguments.
+ */
+static void rtTestXmlOutput(PRTTESTINT pTest, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    rtTestXmlOutputV(pTest, pszFormat, va);
+    va_end(va);
+}
+
+
+/**
+ * Starts the XML stream.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszTest             The test name.
+ */
+static void rtTestXmlStart(PRTTESTINT pTest, const char *pszTest)
+{
+    pTest->cXmlElements = 0;
+    if (pTest->fXmlEnabled)
+    {
+        rtTestXmlOutput(pTest, "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n");
+        pTest->eXmlState = RTTESTINT::kXmlPos_ElementEnd;
+        pTest->fXmlTopTestDone = !(pTest->fFlags & RTTEST_C_XML_DELAY_TOP_TEST) || pTest->fXmlOmitTopTest;
+        if (pTest->fXmlTopTestDone && !pTest->fXmlOmitTopTest)
+            rtTestXmlElemStart(pTest, "Test", "name=%RMas", pszTest);
+    }
+}
+
+
+/**
+ * Emit an XML element that doesn't have any value and instead ends immediately.
+ *
+ * The caller must own the instance lock.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszTag              The element tag.
+ * @param   pszAttrFmt          The element attributes as a format string. Use
+ *                              NULL if none.
+ * @param   va                  Format string arguments.
+ */
+static void rtTestXmlElemV(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, va_list va)
+{
+    if (pTest->fXmlEnabled)
+    {
+        RTTIMESPEC  TimeSpec;
+        RTTIME      Time;
+        char        szTS[80];
+        RTTimeToString(RTTimeExplode(&Time, RTTimeNow(&TimeSpec)), szTS, sizeof(szTS));
+
+        if (pTest->eXmlState != RTTESTINT::kXmlPos_ElementEnd)
+            rtTestXmlOutput(pTest, "\n");
+
+        if (!pszAttrFmt || !*pszAttrFmt)
+            rtTestXmlOutput(pTest, "%*s<%s timestamp=%RMas/>\n",
+                            pTest->cXmlElements * 2, "", pszTag, szTS);
+        else
+        {
+            va_list va2;
+            va_copy(va2, va);
+            rtTestXmlOutput(pTest, "%*s<%s timestamp=%RMas %N/>\n",
+                            pTest->cXmlElements * 2, "", pszTag, szTS, pszAttrFmt, &va2);
+            va_end(va2);
+        }
+        pTest->eXmlState = RTTESTINT::kXmlPos_ElementEnd;
+    }
+}
+
+
+/**
+ * Wrapper around rtTestXmlElemV.
+ */
+static void rtTestXmlElem(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, ...)
+{
+    va_list va;
+    va_start(va, pszAttrFmt);
+    rtTestXmlElemV(pTest, pszTag, pszAttrFmt, va);
+    va_end(va);
+}
+
+
+/**
+ * Starts a new XML element.
+ *
+ * The caller must own the instance lock.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszTag              The element tag.
+ * @param   pszAttrFmt          The element attributes as a format string. Use
+ *                              NULL if none.
+ * @param   va                  Format string arguments.
+ */
+static void rtTestXmlElemStartV(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, va_list va)
+{
+    /* Push it onto the stack. */
+    size_t i = pTest->cXmlElements;
+    AssertReturnVoid(i < RT_ELEMENTS(pTest->apszXmlElements));
+    pTest->apszXmlElements[i] = pszTag;
+    pTest->cXmlElements       = i + 1;
+
+    if (pTest->fXmlEnabled)
+    {
+        RTTIMESPEC  TimeSpec;
+        RTTIME      Time;
+        char        szTS[80];
+        RTTimeToString(RTTimeExplode(&Time, RTTimeNow(&TimeSpec)), szTS, sizeof(szTS));
+
+        if (pTest->eXmlState != RTTESTINT::kXmlPos_ElementEnd)
+            rtTestXmlOutput(pTest, "\n");
+
+        if (!pszAttrFmt || !*pszAttrFmt)
+            rtTestXmlOutput(pTest, "%*s<%s timestamp=%RMas>",
+                            i * 2, "", pszTag, szTS);
+        else
+        {
+            va_list va2;
+            va_copy(va2, va);
+            rtTestXmlOutput(pTest, "%*s<%s timestamp=%RMas %N>",
+                            i * 2, "", pszTag, szTS, pszAttrFmt, &va2);
+            va_end(va2);
+        }
+        pTest->eXmlState = RTTESTINT::kXmlPos_ValueStart;
+    }
+}
+
+
+/**
+ * Wrapper around rtTestXmlElemStartV.
+ */
+static void rtTestXmlElemStart(PRTTESTINT pTest, const char *pszTag, const char *pszAttrFmt, ...)
+{
+    va_list va;
+    va_start(va, pszAttrFmt);
+    rtTestXmlElemStartV(pTest, pszTag, pszAttrFmt, va);
+    va_end(va);
+}
+
+
+/**
+ * Ends the current element.
+ *
+ * The caller must own the instance lock.
+ *
+ * @param   pTest               The test instance.
+ * @param   pszTag              The tag we're ending (chiefly for sanity
+ *                              checking).
+ */
+static void rtTestXmlElemEnd(PRTTESTINT pTest, const char *pszTag)
+{
+    /* pop the element */
+    size_t i = pTest->cXmlElements;
+    AssertReturnVoid(i > 0);
+    i--;
+    AssertReturnVoid(!strcmp(pszTag, pTest->apszXmlElements[i]));
+    pTest->cXmlElements = i;
+
+    /* Do the closing. */
+    if (pTest->fXmlEnabled)
+    {
+        if (pTest->eXmlState == RTTESTINT::kXmlPos_ValueStart)
+            rtTestXmlOutput(pTest, "\n%*s</%s>\n", i * 2, "", pszTag);
+        else if (pTest->eXmlState == RTTESTINT::kXmlPos_ElementEnd)
+            rtTestXmlOutput(pTest, "%*s</%s>\n", i * 2, "", pszTag);
+        else
+            rtTestXmlOutput(pTest, "</%s>\n", pszTag);
+        pTest->eXmlState = RTTESTINT::kXmlPos_ElementEnd;
+    }
+}
+
+
+/**
+ * Ends the XML stream, closing all open elements.
+ *
+ * The caller must own the instance lock.
+ *
+ * @param   pTest               The test instance.
+ */
+static void rtTestXmlEnd(PRTTESTINT pTest)
+{
+    if (pTest->fXmlEnabled)
+    {
+        /*
+         * Close all the elements and add the final TestEnd one to get a
+         * final timestamp and some certainty that the XML is valid.
+         */
+        size_t i = pTest->cXmlElements;
+        AssertReturnVoid(i > 0 || pTest->fXmlOmitTopTest || !pTest->fXmlTopTestDone);
+        while (i-- > 1)
+        {
+            const char *pszTag = pTest->apszXmlElements[pTest->cXmlElements];
+            if (pTest->eXmlState == RTTESTINT::kXmlPos_ValueStart)
+                rtTestXmlOutput(pTest, "\n%*s</%s>\n", i * 2, "", pszTag);
+            else if (pTest->eXmlState == RTTESTINT::kXmlPos_ElementEnd)
+                rtTestXmlOutput(pTest, "%*s</%s>\n", i * 2, "", pszTag);
+            else
+                rtTestXmlOutput(pTest, "</%s>\n", pszTag);
+            pTest->eXmlState = RTTESTINT::kXmlPos_ElementEnd;
+        }
+
+        if (!pTest->fXmlOmitTopTest && pTest->fXmlTopTestDone)
+        {
+            rtTestXmlElem(pTest, "End", "SubTests=\"%u\" SubTestsFailed=\"%u\" errors=\"%u\"",
+                          pTest->cSubTests, pTest->cSubTestsFailed, pTest->cErrors);
+            rtTestXmlOutput(pTest, "</Test>\n");
+        }
+
+        /*
+         * Close the XML outputs.
+         */
+        if (pTest->hXmlPipe != NIL_RTPIPE)
+        {
+            RTPipeClose(pTest->hXmlPipe);
+            pTest->hXmlPipe = NIL_RTPIPE;
+        }
+        if (pTest->hXmlFile != NIL_RTFILE)
+        {
+            RTFileClose(pTest->hXmlFile);
+            pTest->hXmlFile = NIL_RTFILE;
+        }
+        pTest->fXmlEnabled = false;
+        pTest->eXmlState = RTTESTINT::kXmlPos_ElementEnd;
+    }
+    pTest->cXmlElements = 0;
+}
+
+/**
+ * Output callback.
+ *
+ * @returns number of bytes written.
+ * @param   pvArg       User argument.
+ * @param   pachChars   Pointer to an array of utf-8 characters.
+ * @param   cbChars     Number of bytes in the character array pointed to by pachChars.
+ */
+static DECLCALLBACK(size_t) rtTestPrintfOutput(void *pvArg, const char *pachChars, size_t cbChars)
+{
+    size_t      cch   = 0;
+    PRTTESTINT  pTest = (PRTTESTINT)pvArg;
+    if (cbChars)
+    {
+        do
+        {
+            /* insert prefix if at a newline. */
+            if (pTest->fNewLine)
+            {
+                RTStrmWrite(pTest->pOutStrm, pTest->pszTest, pTest->cchTest);
+                RTStrmWrite(pTest->pOutStrm, ": ", 2);
+                cch += 2 + pTest->cchTest;
+            }
+
+            /* look for newline and write the stuff. */
+            const char *pchEnd = (const char *)memchr(pachChars, '\n', cbChars);
+            if (!pchEnd)
+            {
+                pTest->fNewLine = false;
+                RTStrmWrite(pTest->pOutStrm, pachChars, cbChars);
+                cch += cbChars;
+                break;
+            }
+
+            pTest->fNewLine = true;
+            size_t const cchPart = pchEnd - pachChars + 1;
+            RTStrmWrite(pTest->pOutStrm, pachChars, cchPart);
+            cch       += cchPart;
+            pachChars += cchPart;
+            cbChars   -= cchPart;
+        } while (cbChars);
+    }
+    else
+        RTStrmFlush(pTest->pOutStrm);
+    return cch;
+}
+
+
+/**
+ * Internal output worker.
+ *
+ * Caller takes the lock.
+ *
+ * @returns Number of chars printed.
+ * @param   pTest           The test instance.
+ * @param   pszFormat       The message.
+ * @param   va              The arguments.
+ */
+static int rtTestPrintfV(PRTTESTINT pTest, const char *pszFormat, va_list va)
+{
+    return (int)RTStrFormatV(rtTestPrintfOutput, pTest, NULL, NULL, pszFormat, va);
+}
+
+
+/**
+ * Internal output worker.
+ *
+ * Caller takes the lock.
+ *
+ * @returns Number of chars printed.
+ * @param   pTest           The test instance.
+ * @param   pszFormat       The message.
+ * @param   ...             The arguments.
+ */
+static int rtTestPrintf(PRTTESTINT pTest, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = rtTestPrintfV(pTest, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPrintfNlV(RTTEST hTest, RTTESTLVL enmLevel, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, -1);
+
+    RTCritSectEnter(&pTest->OutputLock);
+
+    int cch = 0;
+    if (enmLevel <= pTest->enmMaxLevel)
+    {
+        if (!pTest->fNewLine)
+            cch += rtTestPrintf(pTest, "\n");
+        cch += rtTestPrintfV(pTest, pszFormat, va);
+    }
+
+    RTCritSectLeave(&pTest->OutputLock);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPrintfNl(RTTEST hTest, RTTESTLVL enmLevel, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = RTTestPrintfNlV(hTest, enmLevel, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPrintfV(RTTEST hTest, RTTESTLVL enmLevel, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, -1);
+
+    RTCritSectEnter(&pTest->OutputLock);
+    int cch = 0;
+    if (enmLevel <= pTest->enmMaxLevel)
+        cch += rtTestPrintfV(pTest, pszFormat, va);
+    RTCritSectLeave(&pTest->OutputLock);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPrintf(RTTEST hTest, RTTESTLVL enmLevel, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = RTTestPrintfV(hTest, enmLevel, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestBanner(RTTEST hTest)
+{
+    return RTTestPrintfNl(hTest, RTTESTLVL_ALWAYS, "TESTING...\n");
+}
+
+
+/**
+ * Prints the result of a sub-test if necessary.
+ *
+ * @returns Number of chars printed.
+ * @param   pTest       The test instance.
+ * @remarks Caller own the test Lock.
+ */
+static int rtTestSubTestReport(PRTTESTINT pTest)
+{
+    int cch = 0;
+    if (    !pTest->fSubTestReported
+        &&  pTest->pszSubTest)
+    {
+        pTest->fSubTestReported = true;
+        uint32_t cErrors = ASMAtomicUoReadU32(&pTest->cErrors) - pTest->cSubTestAtErrors;
+        if (!cErrors)
+        {
+            if (!pTest->fSubTestSkipped)
+            {
+                rtTestXmlElem(pTest, "Passed", NULL);
+                rtTestXmlElemEnd(pTest, "Test");
+                cch += RTTestPrintfNl(pTest, RTTESTLVL_SUB_TEST, "%-60s: PASSED\n", pTest->pszSubTest);
+            }
+            else
+            {
+                rtTestXmlElem(pTest, "Skipped", NULL);
+                rtTestXmlElemEnd(pTest, "Test");
+                cch += RTTestPrintfNl(pTest, RTTESTLVL_SUB_TEST, "%-60s: SKIPPED\n", pTest->pszSubTest);
+            }
+        }
+        else
+        {
+            pTest->cSubTestsFailed++;
+            rtTestXmlElem(pTest, "Failed", "errors=\"%u\"", cErrors);
+            rtTestXmlElemEnd(pTest, "Test");
+            cch += RTTestPrintfNl(pTest, RTTESTLVL_SUB_TEST, "%-60s: FAILED (%u errors)\n",
+                                  pTest->pszSubTest, cErrors);
+        }
+    }
+    return cch;
+}
+
+
+/**
+ * RTTestSub and RTTestSubDone worker that cleans up the current (if any)
+ * sub test.
+ *
+ * @returns Number of chars printed.
+ * @param   pTest       The test instance.
+ * @remarks Caller own the test Lock.
+ */
+static int rtTestSubCleanup(PRTTESTINT pTest)
+{
+    int cch = 0;
+    if (pTest->pszSubTest)
+    {
+        cch += rtTestSubTestReport(pTest);
+
+        RTStrFree((char *)pTest->pszSubTest);
+        pTest->pszSubTest = NULL;
+        pTest->fSubTestReported = true;
+    }
+    RTStrFree(pTest->pszErrCtx);
+    pTest->pszErrCtx = NULL;
+    return cch;
+}
+
+
+RTR3DECL(RTEXITCODE) RTTestSummaryAndDestroy(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, RTEXITCODE_FAILURE);
+
+    RTCritSectEnter(&pTest->Lock);
+    rtTestSubTestReport(pTest);
+    RTCritSectLeave(&pTest->Lock);
+
+    RTEXITCODE enmExitCode;
+    if (!pTest->cErrors)
+    {
+        RTTestPrintfNl(hTest, RTTESTLVL_ALWAYS, "SUCCESS\n");
+        enmExitCode = RTEXITCODE_SUCCESS;
+    }
+    else
+    {
+        RTTestPrintfNl(hTest, RTTESTLVL_ALWAYS, "FAILURE - %u errors\n", pTest->cErrors);
+        enmExitCode = RTEXITCODE_FAILURE;
+    }
+
+    RTTestDestroy(pTest);
+    return enmExitCode;
+}
+
+
+RTR3DECL(RTEXITCODE) RTTestSkipAndDestroyV(RTTEST hTest, const char *pszReasonFmt, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, RTEXITCODE_SKIPPED);
+
+    RTCritSectEnter(&pTest->Lock);
+    rtTestSubTestReport(pTest);
+    RTCritSectLeave(&pTest->Lock);
+
+    RTEXITCODE enmExitCode;
+    if (!pTest->cErrors)
+    {
+        if (pszReasonFmt)
+            RTTestPrintfNlV(hTest, RTTESTLVL_FAILURE, pszReasonFmt, va);
+        RTTestPrintfNl(hTest, RTTESTLVL_ALWAYS, "SKIPPED\n");
+        enmExitCode = RTEXITCODE_SKIPPED;
+    }
+    else
+    {
+        RTTestPrintfNl(hTest, RTTESTLVL_ALWAYS, "FAILURE - %u errors\n", pTest->cErrors);
+        enmExitCode = RTEXITCODE_FAILURE;
+    }
+
+    RTTestDestroy(pTest);
+    return enmExitCode;
+}
+
+
+RTR3DECL(RTEXITCODE) RTTestSkipAndDestroy(RTTEST hTest, const char *pszReasonFmt, ...)
+{
+    va_list va;
+    va_start(va, pszReasonFmt);
+    RTEXITCODE enmExitCode = RTTestSkipAndDestroyV(hTest, pszReasonFmt, va);
+    va_end(va);
+    return enmExitCode;
+}
+
+
+RTR3DECL(int) RTTestSub(RTTEST hTest, const char *pszSubTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, -1);
+
+    RTCritSectEnter(&pTest->Lock);
+
+    /* Cleanup, reporting if necessary previous sub test. */
+    rtTestSubCleanup(pTest);
+
+    /* Start new sub test. */
+    pTest->cSubTests++;
+    pTest->cSubTestAtErrors = ASMAtomicUoReadU32(&pTest->cErrors);
+    pTest->pszSubTest = RTStrDup(pszSubTest);
+    pTest->cchSubTest = strlen(pszSubTest);
+    AssertMsg(pTest->cchSubTest < 64 /* See g_kcchMaxTestResultName in testmanager/config.py. */,
+              ("cchSubTest=%u: '%s'\n", pTest->cchSubTest, pTest->pszSubTest));
+    pTest->fSubTestSkipped  = false;
+    pTest->fSubTestReported = false;
+
+    int cch = 0;
+    if (pTest->enmMaxLevel >= RTTESTLVL_DEBUG)
+        cch = RTTestPrintfNl(hTest, RTTESTLVL_DEBUG, "debug: Starting sub-test '%s'\n", pszSubTest);
+
+    if (!pTest->fXmlTopTestDone)
+    {
+        pTest->fXmlTopTestDone = true;
+        rtTestXmlElemStart(pTest, "Test", "name=%RMas", pTest->pszTest);
+    }
+
+    rtTestXmlElemStart(pTest, "Test", "name=%RMas", pszSubTest);
+
+    RTCritSectLeave(&pTest->Lock);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestSubF(RTTEST hTest, const char *pszSubTestFmt, ...)
+{
+    va_list va;
+    va_start(va, pszSubTestFmt);
+    int cch = RTTestSubV(hTest, pszSubTestFmt, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestSubV(RTTEST hTest, const char *pszSubTestFmt, va_list va)
+{
+    char *pszSubTest;
+    RTStrAPrintfV(&pszSubTest, pszSubTestFmt, va);
+    if (pszSubTest)
+    {
+        int cch = RTTestSub(hTest, pszSubTest);
+        RTStrFree(pszSubTest);
+        return cch;
+    }
+    return 0;
+}
+
+
+RTR3DECL(int) RTTestSubDone(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, VERR_INVALID_HANDLE);
+
+    RTCritSectEnter(&pTest->Lock);
+    int cch = rtTestSubCleanup(pTest);
+    RTCritSectLeave(&pTest->Lock);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPassedV(RTTEST hTest, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    AssertPtr(pszFormat);
+    RTTEST_GET_VALID_RETURN_RC(pTest, VERR_INVALID_HANDLE);
+
+    int cch = 0;
+    if (pTest->enmMaxLevel >= RTTESTLVL_INFO)
+    {
+        va_list va2;
+        va_copy(va2, va);
+
+        RTCritSectEnter(&pTest->OutputLock);
+        cch += rtTestPrintf(pTest, "%N\n", pszFormat, &va2);
+        RTCritSectLeave(&pTest->OutputLock);
+
+        va_end(va2);
+    }
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestPassed(RTTEST hTest, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = RTTestPassedV(hTest, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestSkippedV(RTTEST hTest, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    AssertPtrNull(pszFormat);
+    RTTEST_GET_VALID_RETURN_RC(pTest, VERR_INVALID_HANDLE);
+
+    pTest->fSubTestSkipped = true;
+
+    int cch = 0;
+    if (pszFormat && *pszFormat && pTest->enmMaxLevel >= RTTESTLVL_INFO)
+    {
+        va_list va2;
+        va_copy(va2, va);
+
+        RTCritSectEnter(&pTest->OutputLock);
+        cch += rtTestPrintf(pTest, "%N\n", pszFormat, &va2);
+        RTCritSectLeave(&pTest->OutputLock);
+
+        va_end(va2);
+    }
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestSkipped(RTTEST hTest, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = RTTestSkippedV(hTest, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+
+/**
+ * Gets the unit name.
+ *
+ * @returns Unit name.
+ * @param   enmUnit             The unit.
+ */
+static const char *rtTestUnitName(RTTESTUNIT enmUnit)
+{
+    switch (enmUnit)
+    {
+        case RTTESTUNIT_PCT:                    return "%";
+        case RTTESTUNIT_BYTES:                  return "bytes";
+        case RTTESTUNIT_BYTES_PER_SEC:          return "bytes/s";
+        case RTTESTUNIT_KILOBYTES:              return "KB";
+        case RTTESTUNIT_KILOBYTES_PER_SEC:      return "KB/s";
+        case RTTESTUNIT_MEGABYTES:              return "MB";
+        case RTTESTUNIT_MEGABYTES_PER_SEC:      return "MB/s";
+        case RTTESTUNIT_PACKETS:                return "packets";
+        case RTTESTUNIT_PACKETS_PER_SEC:        return "packets/s";
+        case RTTESTUNIT_FRAMES:                 return "frames";
+        case RTTESTUNIT_FRAMES_PER_SEC:         return "frames/s";
+        case RTTESTUNIT_OCCURRENCES:            return "occurrences";
+        case RTTESTUNIT_OCCURRENCES_PER_SEC:    return "occurrences/s";
+        case RTTESTUNIT_ROUND_TRIP:             return "roundtrips";
+        case RTTESTUNIT_CALLS:                  return "calls";
+        case RTTESTUNIT_CALLS_PER_SEC:          return "calls/s";
+        case RTTESTUNIT_SECS:                   return "s";
+        case RTTESTUNIT_MS:                     return "ms";
+        case RTTESTUNIT_NS:                     return "ns";
+        case RTTESTUNIT_NS_PER_CALL:            return "ns/call";
+        case RTTESTUNIT_NS_PER_FRAME:           return "ns/frame";
+        case RTTESTUNIT_NS_PER_OCCURRENCE:      return "ns/occurrence";
+        case RTTESTUNIT_NS_PER_PACKET:          return "ns/packet";
+        case RTTESTUNIT_NS_PER_ROUND_TRIP:      return "ns/roundtrip";
+        case RTTESTUNIT_INSTRS:                 return "ins";
+        case RTTESTUNIT_INSTRS_PER_SEC:         return "ins/sec";
+        case RTTESTUNIT_NONE:                   return "";
+        case RTTESTUNIT_PP1K:                   return "pp1k";
+        case RTTESTUNIT_PP10K:                  return "pp10k";
+        case RTTESTUNIT_PPM:                    return "ppm";
+        case RTTESTUNIT_PPB:                    return "ppb";
+        case RTTESTUNIT_TICKS:                  return "ticks";
+        case RTTESTUNIT_TICKS_PER_CALL:         return "ticks/call";
+        case RTTESTUNIT_TICKS_PER_OCCURENCE:    return "ticks/occ";
+        case RTTESTUNIT_PAGES:                  return "pages";
+        case RTTESTUNIT_PAGES_PER_SEC:          return "pages/s";
+        case RTTESTUNIT_TICKS_PER_PAGE:         return "ticks/page";
+        case RTTESTUNIT_NS_PER_PAGE:            return "ns/page";
+        case RTTESTUNIT_PS:                     return "ps";
+        case RTTESTUNIT_PS_PER_CALL:            return "ps/call";
+        case RTTESTUNIT_PS_PER_FRAME:           return "ps/frame";
+        case RTTESTUNIT_PS_PER_OCCURRENCE:      return "ps/occurrence";
+        case RTTESTUNIT_PS_PER_PACKET:          return "ps/packet";
+        case RTTESTUNIT_PS_PER_ROUND_TRIP:      return "ps/roundtrip";
+        case RTTESTUNIT_PS_PER_PAGE:            return "ps/page";
+
+        /* No default so gcc helps us keep this up to date. */
+        case RTTESTUNIT_INVALID:
+        case RTTESTUNIT_END:
+            break;
+    }
+    AssertMsgFailed(("%d\n", enmUnit));
+    return "unknown";
+}
+
+
+RTR3DECL(int) RTTestValue(RTTEST hTest, const char *pszName, uint64_t u64Value, RTTESTUNIT enmUnit)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+
+    Assert(strlen(pszName) < 56 /* See g_kcchMaxTestValueName in testmanager/config.py. */);
+
+    const char *pszUnit = rtTestUnitName(enmUnit);
+
+    RTCritSectEnter(&pTest->Lock);
+    rtTestXmlElem(pTest, "Value", "name=%RMas unit=%RMas value=\"%llu\"", pszName, pszUnit, u64Value);
+    RTCritSectLeave(&pTest->Lock);
+
+    RTCritSectEnter(&pTest->OutputLock);
+    rtTestPrintf(pTest, "  %-58s: %'16llu %s\n", pszName, u64Value, pszUnit);
+    RTCritSectLeave(&pTest->OutputLock);
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestValueF(RTTEST hTest, uint64_t u64Value, RTTESTUNIT enmUnit, const char *pszNameFmt, ...)
+{
+    va_list va;
+    va_start(va, pszNameFmt);
+    int rc = RTTestValueV(hTest, u64Value, enmUnit, pszNameFmt, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestValueV(RTTEST hTest, uint64_t u64Value, RTTESTUNIT enmUnit, const char *pszNameFmt, va_list va)
+{
+    char *pszName;
+    RTStrAPrintfV(&pszName, pszNameFmt, va);
+    if (!pszName)
+        return VERR_NO_MEMORY;
+    int rc = RTTestValue(hTest, pszName, u64Value, enmUnit);
+    RTStrFree(pszName);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestErrorInc(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+
+    ASMAtomicIncU32(&pTest->cErrors);
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(uint32_t) RTTestErrorCount(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, UINT32_MAX);
+
+    return ASMAtomicReadU32(&pTest->cErrors);
+}
+
+
+RTR3DECL(uint32_t) RTTestSubErrorCount(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, UINT32_MAX);
+
+    return ASMAtomicReadU32(&pTest->cErrors) - pTest->cSubTestAtErrors;
+}
+
+
+RTR3DECL(int) RTTestFailedV(RTTEST hTest, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN_RC(pTest, VERR_INVALID_HANDLE);
+
+    RTTestErrorInc(pTest);
+
+    int cch = 0;
+    if (pTest->enmMaxLevel >= RTTESTLVL_FAILURE)
+    {
+        va_list va2;
+        va_copy(va2, va);
+
+        const char *pszEnd = strchr(pszFormat, '\0');
+        bool fHasNewLine = pszFormat != pszEnd
+                        && pszEnd[-1] == '\n';
+
+        RTCritSectEnter(&pTest->OutputLock);
+        cch += rtTestPrintf(pTest, fHasNewLine ? "%N" : "%N\n", pszFormat, &va2);
+        if (pTest->pszErrCtx)
+        {
+            cch += rtTestPrintf(pTest, "context: %s\n", pTest->pszErrCtx);
+            RTStrFree(pTest->pszErrCtx);
+            pTest->pszErrCtx = NULL;
+        }
+        RTCritSectLeave(&pTest->OutputLock);
+
+        va_end(va2);
+    }
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestFailed(RTTEST hTest, const char *pszFormat, ...)
+{
+    va_list va;
+
+    va_start(va, pszFormat);
+    int cch = RTTestFailedV(hTest, pszFormat, va);
+    va_end(va);
+
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestFailureDetailsV(RTTEST hTest, const char *pszFormat, va_list va)
+{
+    return RTTestPrintfV(hTest, RTTESTLVL_FAILURE, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestFailureDetails(RTTEST hTest, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int cch = RTTestFailureDetailsV(hTest, pszFormat, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestErrContextV(RTTEST hTest, const char *pszFormat, va_list va)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+
+    RTStrFree(pTest->pszErrCtx);
+    pTest->pszErrCtx = NULL;
+
+    if (pszFormat && *pszFormat)
+    {
+        pTest->pszErrCtx = RTStrAPrintf2V(pszFormat, va);
+        AssertReturn(pTest->pszErrCtx, VERR_NO_STR_MEMORY);
+        RTStrStripR(pTest->pszErrCtx);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestErrContext(RTTEST hTest, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTTestErrContextV(hTest, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestDisableAssertions(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+
+    uint32_t cTimes = ASMAtomicIncU32(&pTest->cAssertionsDisabledAndQuieted);
+    if (cTimes >= 2 && cTimes <= 8)
+        return VINF_SUCCESS;
+    if (cTimes > 8)
+    {
+        RTAssertSetMayPanic(pTest->fAssertSavedMayPanic);
+        RTAssertSetQuiet(pTest->fAssertSavedQuiet);
+        Assert(cTimes <= 8);
+    }
+    pTest->fAssertSavedMayPanic = RTAssertSetMayPanic(false);
+    pTest->fAssertSavedQuiet    = RTAssertSetQuiet(true);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTTestRestoreAssertions(RTTEST hTest)
+{
+    PRTTESTINT pTest = hTest;
+    RTTEST_GET_VALID_RETURN(pTest);
+
+    uint32_t cTimes = ASMAtomicDecU32(&pTest->cAssertionsDisabledAndQuieted);
+    if (cTimes == 0)
+    {
+        RTAssertSetMayPanic(pTest->fAssertSavedMayPanic);
+        RTAssertSetQuiet(pTest->fAssertSavedQuiet);
+    }
+    else
+        AssertStmt(cTimes < UINT32_MAX / 2, ASMAtomicIncU32(&pTest->cAssertionsDisabledAndQuieted));
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/testi.cpp b/src/VBox/Runtime/r3/testi.cpp
new file mode 100644
index 00000000..28daa7bc
--- /dev/null
+++ b/src/VBox/Runtime/r3/testi.cpp
@@ -0,0 +1,214 @@
+/* $Id: testi.cpp $ */
+/** @file
+ * IPRT - Testcase Framework, the implicit test handle API variation.
+ */
+
+/*
+ * Copyright (C) 2009-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/test.h>
+#include <iprt/stdarg.h>
+
+
+RTR3DECL(int) RTTestIPrintfV(RTTESTLVL enmLevel, const char *pszFormat, va_list va)
+{
+    return RTTestPrintfV(NIL_RTTEST, enmLevel, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestIPrintf(RTTESTLVL enmLevel, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int cch = RTTestPrintfV(NIL_RTTEST, enmLevel, pszFormat, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestISub(const char *pszSubTest)
+{
+    return RTTestSub(NIL_RTTEST, pszSubTest);
+}
+
+
+RTR3DECL(int) RTTestISubF(const char *pszSubTestFmt, ...)
+{
+    va_list va;
+    va_start(va, pszSubTestFmt);
+    int cch = RTTestSubV(NIL_RTTEST, pszSubTestFmt, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestISubV(const char *pszSubTestFmt, va_list va)
+{
+    return RTTestSubV(NIL_RTTEST, pszSubTestFmt, va);
+}
+
+
+RTR3DECL(int) RTTestISubDone(void)
+{
+    return RTTestSubDone(NIL_RTTEST);
+}
+
+
+RTR3DECL(int) RTTestIPassedV(const char *pszFormat, va_list va)
+{
+    return RTTestPassedV(NIL_RTTEST, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestIPassed(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int cch = RTTestPassedV(NIL_RTTEST, pszFormat, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestIValue(const char *pszName, uint64_t u64Value, RTTESTUNIT enmUnit)
+{
+    return RTTestValue(NIL_RTTEST, pszName, u64Value, enmUnit);
+}
+
+
+RTR3DECL(int) RTTestIValueF(uint64_t u64Value, RTTESTUNIT enmUnit, const char *pszNameFmt, ...)
+{
+    va_list va;
+    va_start(va, pszNameFmt);
+    int rc = RTTestValueV(NIL_RTTEST, u64Value, enmUnit, pszNameFmt, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestIValueV(uint64_t u64Value, RTTESTUNIT enmUnit, const char *pszNameFmt, va_list va)
+{
+    return RTTestValueV(NIL_RTTEST, u64Value, enmUnit, pszNameFmt, va);
+}
+
+
+RTR3DECL(int) RTTestIErrorInc(void)
+{
+    return RTTestErrorInc(NIL_RTTEST);
+}
+
+
+RTR3DECL(uint32_t) RTTestIErrorCount(void)
+{
+    return RTTestErrorCount(NIL_RTTEST);
+}
+
+
+RTR3DECL(int) RTTestIFailedV(const char *pszFormat, va_list va)
+{
+    return RTTestFailedV(NIL_RTTEST, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestIFailed(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int cch = RTTestFailedV(NIL_RTTEST, pszFormat, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestIFailedRcV(int rcRet, const char *pszFormat, va_list va)
+{
+    RTTestFailedV(NIL_RTTEST, pszFormat, va);
+    return rcRet;
+}
+
+
+RTR3DECL(int) RTTestIFailedRc(int rcRet, const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    RTTestFailedV(NIL_RTTEST, pszFormat, va);
+    va_end(va);
+    return rcRet;
+}
+
+
+RTR3DECL(int) RTTestIFailureDetailsV(const char *pszFormat, va_list va)
+{
+    return RTTestFailureDetails(NIL_RTTEST, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestIFailureDetails(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int cch = RTTestFailureDetailsV(NIL_RTTEST, pszFormat, va);
+    va_end(va);
+    return cch;
+}
+
+
+RTR3DECL(int) RTTestIErrContextV(const char *pszFormat, va_list va)
+{
+    return RTTestErrContextV(NIL_RTTEST, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTTestIErrContext(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTTestErrContextV(NIL_RTTEST, pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+
+RTR3DECL(int) RTTestIDisableAssertions(void)
+{
+    return RTTestDisableAssertions(NIL_RTTEST);
+}
+
+
+RTR3DECL(int) RTTestIRestoreAssertions(void)
+{
+    return RTTestRestoreAssertions(NIL_RTTEST);
+}
+
diff --git a/src/VBox/Runtime/r3/udp.cpp b/src/VBox/Runtime/r3/udp.cpp
new file mode 100644
index 00000000..2ed12047
--- /dev/null
+++ b/src/VBox/Runtime/r3/udp.cpp
@@ -0,0 +1,726 @@
+/* $Id: udp.cpp $ */
+/** @file
+ * IPRT - UDP/IP.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef RT_OS_WINDOWS
+# include <iprt/win/winsock2.h>
+#else
+# include <sys/types.h>
+# include <sys/socket.h>
+# include <errno.h>
+# include <netinet/in.h>
+# include <netinet/udp.h>
+# include <arpa/inet.h>
+# include <netdb.h>
+#endif
+#include <limits.h>
+
+#include "internal/iprt.h"
+#include <iprt/udp.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mempool.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/socket.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+
+#include "internal/magics.h"
+#include "internal/socket.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/* fixup backlevel OSes. */
+#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS)
+# define socklen_t              int
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * UDP Server state.
+ */
+typedef enum RTUDPSERVERSTATE
+{
+    /** Invalid. */
+    RTUDPSERVERSTATE_INVALID = 0,
+    /** Created. */
+    RTUDPSERVERSTATE_CREATED,
+    /** Thread for incoming datagrams is starting up. */
+    RTUDPSERVERSTATE_STARTING,
+    /** Waiting for incoming datagrams. */
+    RTUDPSERVERSTATE_WAITING,
+    /** Handling an incoming datagram. */
+    RTUDPSERVERSTATE_RECEIVING,
+    /** Thread terminating. */
+    RTUDPSERVERSTATE_STOPPING,
+    /** Thread terminated. */
+    RTUDPSERVERSTATE_STOPPED,
+    /** Final cleanup before being unusable. */
+    RTUDPSERVERSTATE_DESTROYING
+} RTUDPSERVERSTATE;
+
+/*
+ * Internal representation of the UDP Server handle.
+ */
+typedef struct RTUDPSERVER
+{
+    /** The magic value (RTUDPSERVER_MAGIC). */
+    uint32_t volatile           u32Magic;
+    /** The server state. */
+    RTUDPSERVERSTATE volatile   enmState;
+    /** The server thread. */
+    RTTHREAD                    Thread;
+    /** The server socket. */
+    RTSOCKET volatile           hSocket;
+    /** The datagram receiver function. */
+    PFNRTUDPSERVE               pfnServe;
+    /** Argument to pfnServer. */
+    void                       *pvUser;
+} RTUDPSERVER;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static DECLCALLBACK(int)  rtUdpServerThread(RTTHREAD ThreadSelf, void *pvServer);
+static int  rtUdpServerListen(PRTUDPSERVER pServer);
+static int  rtUdpServerListenCleanup(PRTUDPSERVER pServer);
+static int  rtUdpServerDestroySocket(RTSOCKET volatile *pSock, const char *pszMsg);
+static int  rtUdpClose(RTSOCKET Sock, const char *pszMsg);
+
+
+/**
+ * Atomicly updates a socket variable.
+ * @returns The old handle value.
+ * @param   phSock          The socket handle variable to update.
+ * @param   hNew            The new socket handle value.
+ */
+DECLINLINE(RTSOCKET) rtUdpAtomicXchgSock(RTSOCKET volatile *phSock, const RTSOCKET hNew)
+{
+    RTSOCKET hRet;
+    ASMAtomicXchgHandle(phSock, hNew, &hRet);
+    return hRet;
+}
+
+
+/**
+ * Tries to change the UDP server state.
+ */
+DECLINLINE(bool) rtUdpServerTrySetState(PRTUDPSERVER pServer, RTUDPSERVERSTATE enmStateNew, RTUDPSERVERSTATE enmStateOld)
+{
+    bool fRc;
+    ASMAtomicCmpXchgSize(&pServer->enmState, enmStateNew, enmStateOld, fRc);
+    return fRc;
+}
+
+/**
+ * Changes the UDP server state.
+ */
+DECLINLINE(void) rtUdpServerSetState(PRTUDPSERVER pServer, RTUDPSERVERSTATE enmStateNew, RTUDPSERVERSTATE enmStateOld)
+{
+    bool fRc;
+    ASMAtomicCmpXchgSize(&pServer->enmState, enmStateNew, enmStateOld, fRc);
+    Assert(fRc); NOREF(fRc);
+}
+
+
+/**
+ * Closes a socket.
+ *
+ * @returns IPRT status code.
+ */
+static int rtUdpServerDestroySocket(RTSOCKET volatile *pSock, const char *pszMsg)
+{
+    RTSOCKET hSocket = rtUdpAtomicXchgSock(pSock, NIL_RTSOCKET);
+    if (hSocket != NIL_RTSOCKET)
+    {
+        return rtUdpClose(hSocket, pszMsg);
+    }
+    return VINF_UDP_SERVER_NO_CLIENT;
+}
+
+
+RTR3DECL(int)  RTUdpServerCreate(const char *pszAddress, unsigned uPort, RTTHREADTYPE enmType, const char *pszThrdName,
+                                 PFNRTUDPSERVE pfnServe, void *pvUser, PPRTUDPSERVER ppServer)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfnServe, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszThrdName, VERR_INVALID_POINTER);
+    AssertPtrReturn(ppServer, VERR_INVALID_POINTER);
+
+    /*
+     * Create the server.
+     */
+    PRTUDPSERVER pServer;
+    int rc = RTUdpServerCreateEx(pszAddress, uPort, &pServer);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Create the listener thread.
+         */
+        RTMemPoolRetain(pServer);
+        pServer->enmState   = RTUDPSERVERSTATE_STARTING;
+        pServer->pvUser     = pvUser;
+        pServer->pfnServe   = pfnServe;
+        rc = RTThreadCreate(&pServer->Thread, rtUdpServerThread, pServer, 0, enmType, /*RTTHREADFLAGS_WAITABLE*/0, pszThrdName);
+        if (RT_SUCCESS(rc))
+        {
+            /* done */
+            if (ppServer)
+                *ppServer = pServer;
+            else
+                RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            return rc;
+        }
+        RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+
+        /*
+         * Destroy the server.
+         */
+        rtUdpServerSetState(pServer, RTUDPSERVERSTATE_CREATED, RTUDPSERVERSTATE_STARTING);
+        RTUdpServerDestroy(pServer);
+    }
+
+    return rc;
+}
+
+
+/**
+ * Server thread, loops waiting for datagrams until it's terminated.
+ *
+ * @returns iprt status code. (ignored).
+ * @param   ThreadSelf      Thread handle.
+ * @param   pvServer        Server handle.
+ */
+static DECLCALLBACK(int)  rtUdpServerThread(RTTHREAD ThreadSelf, void *pvServer)
+{
+    PRTUDPSERVER    pServer = (PRTUDPSERVER)pvServer;
+    int             rc;
+    if (rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_WAITING, RTUDPSERVERSTATE_STARTING))
+        rc = rtUdpServerListen(pServer);
+    else
+        rc = rtUdpServerListenCleanup(pServer);
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    NOREF(ThreadSelf);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTUdpServerCreateEx(const char *pszAddress, uint32_t uPort, PPRTUDPSERVER ppServer)
+{
+
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(ppServer, VERR_INVALID_PARAMETER);
+
+    /*
+     * Resolve the address.
+     */
+    RTNETADDR LocalAddr;
+    int rc = RTSocketParseInetAddress(pszAddress, uPort, &LocalAddr);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Setting up socket.
+     */
+    RTSOCKET Sock;
+    rc = rtSocketCreate(&Sock, AF_INET, SOCK_DGRAM, IPPROTO_UDP, false /*fInheritable*/);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Set socket options.
+         */
+        int fFlag = 1;
+        if (!rtSocketSetOpt(Sock, SOL_SOCKET, SO_REUSEADDR, &fFlag, sizeof(fFlag)))
+        {
+            /*
+             * Bind a name to the socket.
+             */
+            rc = rtSocketBind(Sock, &LocalAddr);
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Create the server handle.
+                 */
+                PRTUDPSERVER pServer = (PRTUDPSERVER)RTMemPoolAlloc(RTMEMPOOL_DEFAULT, sizeof(*pServer));
+                if (pServer)
+                {
+                    pServer->u32Magic   = RTUDPSERVER_MAGIC;
+                    pServer->enmState   = RTUDPSERVERSTATE_CREATED;
+                    pServer->Thread     = NIL_RTTHREAD;
+                    pServer->hSocket    = Sock;
+                    pServer->pfnServe   = NULL;
+                    pServer->pvUser     = NULL;
+                    *ppServer = pServer;
+                    return VINF_SUCCESS;
+                }
+
+                /* bail out */
+                rc = VERR_NO_MEMORY;
+            }
+        }
+        else
+            AssertMsgFailed(("rtSocketSetOpt: %Rrc\n", rc));
+        rtUdpClose(Sock, "RTServerCreateEx");
+    }
+
+    return rc;
+}
+
+
+RTR3DECL(int) RTUdpServerListen(PRTUDPSERVER pServer, PFNRTUDPSERVE pfnServe, void *pvUser)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pfnServe, VERR_INVALID_POINTER);
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTUDPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    int rc = VERR_INVALID_STATE;
+    if (rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_WAITING, RTUDPSERVERSTATE_CREATED))
+    {
+        Assert(!pServer->pfnServe);
+        Assert(!pServer->pvUser);
+        Assert(pServer->Thread == NIL_RTTHREAD);
+
+        pServer->pfnServe = pfnServe;
+        pServer->pvUser   = pvUser;
+        pServer->Thread   = RTThreadSelf();
+        Assert(pServer->Thread != NIL_RTTHREAD);
+        rc = rtUdpServerListen(pServer);
+    }
+    else
+    {
+        AssertMsgFailed(("enmState=%d\n", pServer->enmState));
+        rc = VERR_INVALID_STATE;
+    }
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return rc;
+}
+
+
+/**
+ * Internal worker common for RTUdpServerListen and the thread created by
+ * RTUdpServerCreate().
+ *
+ * The caller makes sure it has its own memory reference and releases it upon
+ * return.
+ */
+static int rtUdpServerListen(PRTUDPSERVER pServer)
+{
+    /*
+     * Wait for incoming datagrams loop.
+     */
+    for (;;)
+    {
+        /*
+         * Change state, getting an extra reference to the socket so we can
+         * allow others to close it while we're stuck in rtSocketAccept.
+         */
+        RTUDPSERVERSTATE    enmState      = pServer->enmState;
+        RTSOCKET            hSocket;
+        ASMAtomicReadHandle(&pServer->hSocket, &hSocket);
+        if (hSocket != NIL_RTSOCKET)
+            RTSocketRetain(hSocket);
+        if (    enmState != RTUDPSERVERSTATE_WAITING
+            &&  enmState != RTUDPSERVERSTATE_RECEIVING)
+        {
+            RTSocketRelease(hSocket);
+            return rtUdpServerListenCleanup(pServer);
+        }
+        if (!rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_WAITING, enmState))
+        {
+            RTSocketRelease(hSocket);
+            continue;
+        }
+
+        /*
+         * Wait for incoming datagrams or errors.
+         */
+        uint32_t fEvents;
+        int rc = RTSocketSelectOneEx(hSocket, RTSOCKET_EVT_READ | RTSOCKET_EVT_ERROR, &fEvents, 1000);
+        RTSocketRelease(hSocket);
+        if (rc == VERR_TIMEOUT)
+            continue;
+        if (RT_FAILURE(rc))
+        {
+            /* These are typical for what can happen during destruction. */
+            if (   rc == VERR_INVALID_HANDLE
+                || rc == VERR_INVALID_PARAMETER
+                || rc == VERR_NET_NOT_SOCKET)
+                return rtUdpServerListenCleanup(pServer);
+            continue;
+        }
+        if (fEvents & RTSOCKET_EVT_ERROR)
+            return rtUdpServerListenCleanup(pServer);
+
+        /*
+         * Run a pfnServe callback.
+         */
+        if (!rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_RECEIVING, RTUDPSERVERSTATE_WAITING))
+            return rtUdpServerListenCleanup(pServer);
+        rc = pServer->pfnServe(hSocket, pServer->pvUser);
+
+        /*
+         * Stop the server?
+         */
+        if (rc == VERR_UDP_SERVER_STOP)
+        {
+            if (rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_STOPPING, RTUDPSERVERSTATE_RECEIVING))
+            {
+                /*
+                 * Reset the server socket and change the state to stopped. After that state change
+                 * we cannot safely access the handle so we'll have to return here.
+                 */
+                hSocket = rtUdpAtomicXchgSock(&pServer->hSocket, NIL_RTSOCKET);
+                rtUdpServerSetState(pServer, RTUDPSERVERSTATE_STOPPED, RTUDPSERVERSTATE_STOPPING);
+                rtUdpClose(hSocket, "Listener: server stopped");
+            }
+            else
+                rtUdpServerListenCleanup(pServer); /* ignore rc */
+            return rc;
+        }
+    }
+}
+
+
+/**
+ * Clean up after listener.
+ */
+static int rtUdpServerListenCleanup(PRTUDPSERVER pServer)
+{
+    /*
+     * Close the server socket.
+     */
+    rtUdpServerDestroySocket(&pServer->hSocket, "ListenCleanup");
+
+    /*
+     * Figure the return code and make sure the state is OK.
+     */
+    RTUDPSERVERSTATE enmState = pServer->enmState;
+    switch (enmState)
+    {
+        case RTUDPSERVERSTATE_STOPPING:
+        case RTUDPSERVERSTATE_STOPPED:
+            return VERR_UDP_SERVER_SHUTDOWN;
+
+        case RTUDPSERVERSTATE_WAITING:
+            rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_STOPPED, enmState);
+            return VERR_UDP_SERVER_DESTROYED;
+
+        case RTUDPSERVERSTATE_DESTROYING:
+            return VERR_UDP_SERVER_DESTROYED;
+
+        case RTUDPSERVERSTATE_STARTING:
+        case RTUDPSERVERSTATE_RECEIVING:
+        default:
+            AssertMsgFailedReturn(("pServer=%p enmState=%d\n", pServer, enmState), VERR_INTERNAL_ERROR_4);
+    }
+}
+
+
+RTR3DECL(int) RTUdpServerShutdown(PRTUDPSERVER pServer)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTUDPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    /*
+     * Try change the state to stopping, then replace and destroy the server socket.
+     */
+    for (;;)
+    {
+        RTUDPSERVERSTATE enmState = pServer->enmState;
+        if (    enmState != RTUDPSERVERSTATE_WAITING
+            &&  enmState != RTUDPSERVERSTATE_RECEIVING)
+        {
+            RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            switch (enmState)
+            {
+                case RTUDPSERVERSTATE_CREATED:
+                case RTUDPSERVERSTATE_STARTING:
+                default:
+                    AssertMsgFailed(("%d\n", enmState));
+                    return VERR_INVALID_STATE;
+
+                case RTUDPSERVERSTATE_STOPPING:
+                case RTUDPSERVERSTATE_STOPPED:
+                    return VINF_SUCCESS;
+
+                case RTUDPSERVERSTATE_DESTROYING:
+                    return VERR_UDP_SERVER_DESTROYED;
+            }
+        }
+        if (rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_STOPPING, enmState))
+        {
+            rtUdpServerDestroySocket(&pServer->hSocket, "RTUdpServerShutdown");
+            rtUdpServerSetState(pServer, RTUDPSERVERSTATE_STOPPED, RTUDPSERVERSTATE_STOPPING);
+
+            RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+            return VINF_SUCCESS;
+        }
+    }
+}
+
+
+RTR3DECL(int) RTUdpServerDestroy(PRTUDPSERVER pServer)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTUDPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE); /* paranoia */
+
+    /*
+     * Move the state along so the listener can figure out what's going on.
+     */
+    for (;;)
+    {
+        bool             fDestroyable;
+        RTUDPSERVERSTATE enmState = pServer->enmState;
+        switch (enmState)
+        {
+            case RTUDPSERVERSTATE_STARTING:
+            case RTUDPSERVERSTATE_WAITING:
+            case RTUDPSERVERSTATE_RECEIVING:
+            case RTUDPSERVERSTATE_CREATED:
+            case RTUDPSERVERSTATE_STOPPED:
+                fDestroyable = rtUdpServerTrySetState(pServer, RTUDPSERVERSTATE_DESTROYING, enmState);
+                break;
+
+            /* destroyable states */
+            case RTUDPSERVERSTATE_STOPPING:
+                fDestroyable = true;
+                break;
+
+            /*
+             * Everything else means user or internal misbehavior.
+             */
+            default:
+                AssertMsgFailed(("pServer=%p enmState=%d\n", pServer, enmState));
+                RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+                return VERR_INTERNAL_ERROR;
+        }
+        if (fDestroyable)
+            break;
+    }
+
+    /*
+     * Destroy it.
+     */
+    ASMAtomicWriteU32(&pServer->u32Magic, ~RTUDPSERVER_MAGIC);
+    rtUdpServerDestroySocket(&pServer->hSocket, "Destroyer: server");
+
+    /*
+     * Release it.
+     */
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Internal close function which does all the proper bitching.
+ */
+static int rtUdpClose(RTSOCKET Sock, const char *pszMsg)
+{
+    NOREF(pszMsg); /** @todo drop this parameter? */
+
+    /* ignore nil handles. */
+    if (Sock == NIL_RTSOCKET)
+        return VINF_SUCCESS;
+
+    /*
+     * Close the socket handle (drops our reference to it).
+     */
+    return RTSocketClose(Sock);
+}
+
+
+RTR3DECL(int) RTUdpRead(RTSOCKET Sock, void *pvBuffer, size_t cbBuffer, size_t *pcbRead, PRTNETADDR pSrcAddr)
+{
+    if (!RT_VALID_PTR(pcbRead))
+        return VERR_INVALID_POINTER;
+    return RTSocketReadFrom(Sock, pvBuffer, cbBuffer, pcbRead, pSrcAddr);
+}
+
+
+RTR3DECL(int)  RTUdpWrite(PRTUDPSERVER pServer, const void *pvBuffer, size_t cbBuffer, PCRTNETADDR pDstAddr)
+{
+    /*
+     * Validate input and retain the instance.
+     */
+    AssertPtrReturn(pServer, VERR_INVALID_HANDLE);
+    AssertReturn(pServer->u32Magic == RTUDPSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTMemPoolRetain(pServer) != UINT32_MAX, VERR_INVALID_HANDLE);
+
+    RTSOCKET hSocket;
+    ASMAtomicReadHandle(&pServer->hSocket, &hSocket);
+    if (hSocket == NIL_RTSOCKET)
+    {
+        RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+        return VERR_INVALID_HANDLE;
+    }
+    RTSocketRetain(hSocket);
+
+    int rc = VINF_SUCCESS;
+    RTUDPSERVERSTATE enmState = pServer->enmState;
+    if (    enmState != RTUDPSERVERSTATE_CREATED
+        &&  enmState != RTUDPSERVERSTATE_STARTING
+        &&  enmState != RTUDPSERVERSTATE_WAITING
+        &&  enmState != RTUDPSERVERSTATE_RECEIVING
+        &&  enmState != RTUDPSERVERSTATE_STOPPING)
+        rc = VERR_INVALID_STATE;
+
+    if (RT_SUCCESS(rc))
+        rc = RTSocketWriteTo(hSocket, pvBuffer, cbBuffer, pDstAddr);
+
+    RTSocketRelease(hSocket);
+    RTMemPoolRelease(RTMEMPOOL_DEFAULT, pServer);
+
+    return rc;
+}
+
+
+RTR3DECL(int) RTUdpCreateClientSocket(const char *pszAddress, uint32_t uPort, PRTNETADDR pLocalAddr, PRTSOCKET pSock)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszAddress, VERR_INVALID_POINTER);
+    AssertPtrReturn(pSock, VERR_INVALID_POINTER);
+
+    /*
+     * Resolve the address.
+     */
+    RTNETADDR Addr;
+    int rc = RTSocketParseInetAddress(pszAddress, uPort, &Addr);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Create the socket and connect.
+     */
+    RTSOCKET Sock;
+    rc = rtSocketCreate(&Sock, AF_INET, SOCK_DGRAM, 0, false /*fInheritable*/);
+    if (RT_SUCCESS(rc))
+    {
+        if (pLocalAddr)
+            rc = rtSocketBind(Sock, pLocalAddr);
+        if (RT_SUCCESS(rc))
+        {
+            rc = rtSocketConnect(Sock, &Addr, RT_SOCKETCONNECT_DEFAULT_WAIT);
+            if (RT_SUCCESS(rc))
+            {
+                *pSock = Sock;
+                return VINF_SUCCESS;
+            }
+        }
+        RTSocketClose(Sock);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTUdpCreateServerSocket(const char *pszAddress, uint32_t uPort, PRTSOCKET pSock)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(uPort > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszAddress, VERR_INVALID_POINTER);
+    AssertPtrReturn(pSock, VERR_INVALID_POINTER);
+
+    /*
+     * Resolve the address.
+     */
+    RTNETADDR LocalAddr;
+    int rc = RTSocketParseInetAddress(pszAddress, uPort, &LocalAddr);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Setting up socket.
+     */
+    RTSOCKET Sock;
+    rc = rtSocketCreate(&Sock, AF_INET, SOCK_DGRAM, IPPROTO_UDP, false /*fInheritable*/);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Set socket options.
+         */
+        int fFlag = 1;
+        if (!rtSocketSetOpt(Sock, SOL_SOCKET, SO_REUSEADDR, &fFlag, sizeof(fFlag)))
+        {
+            /*
+             * Bind a name to the socket.
+             */
+            rc = rtSocketBind(Sock, &LocalAddr);
+            if (RT_SUCCESS(rc))
+            {
+                *pSock = Sock;
+                return VINF_SUCCESS;
+            }
+        }
+        RTSocketClose(Sock);
+    }
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/win/Makefile.kup b/src/VBox/Runtime/r3/win/Makefile.kup
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/Makefile.kup
diff --git a/src/VBox/Runtime/r3/win/RTCrStoreCreateSnapshotById-win.cpp b/src/VBox/Runtime/r3/win/RTCrStoreCreateSnapshotById-win.cpp
new file mode 100644
index 00000000..1eead2b1
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTCrStoreCreateSnapshotById-win.cpp
@@ -0,0 +1,194 @@
+/* $Id: RTCrStoreCreateSnapshotById-win.cpp $ */
+/** @file
+ * IPRT - RTCrStoreCreateSnapshotById, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/crypto/store.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/once.h>
+#include <iprt/ldr.h>
+
+#include <iprt/win/windows.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef HCERTSTORE (WINAPI *PFNCERTOPENSTORE)(PCSTR pszStoreProvider, DWORD dwEncodingType, HCRYPTPROV_LEGACY hCryptProv,
+                                              DWORD dwFlags, const void *pvParam);
+typedef BOOL (WINAPI *PFNCERTCLOSESTORE)(HCERTSTORE hCertStore, DWORD dwFlags);
+typedef PCCERT_CONTEXT (WINAPI *PFNCERTENUMCERTIFICATESINSTORE)(HCERTSTORE hCertStore, PCCERT_CONTEXT pPrevCertContext);
+
+
+
+static int rtCrStoreAddCertsFromNative(RTCRSTORE hStore, DWORD fStore, PCRTUTF16 pwszStoreName,
+                                       PFNCERTOPENSTORE pfnOpenStore, PFNCERTCLOSESTORE pfnCloseStore,
+                                       PFNCERTENUMCERTIFICATESINSTORE pfnEnumCerts, int rc, PRTERRINFO pErrInfo)
+{
+    DWORD fOpenStore = CERT_STORE_OPEN_EXISTING_FLAG | CERT_STORE_READONLY_FLAG;
+    HCERTSTORE hNativeStore = pfnOpenStore(CERT_STORE_PROV_SYSTEM_W, PKCS_7_ASN_ENCODING | X509_ASN_ENCODING,
+                                           NULL /* hCryptProv = default */, fStore | fOpenStore, pwszStoreName);
+    if (hNativeStore)
+    {
+        PCCERT_CONTEXT pCurCtx = NULL;
+        while ((pCurCtx = pfnEnumCerts(hNativeStore, pCurCtx)) != NULL)
+        {
+            if (pCurCtx->dwCertEncodingType & X509_ASN_ENCODING)
+            {
+                RTERRINFOSTATIC StaticErrInfo;
+                RTASN1CURSORPRIMARY PrimaryCursor;
+                RTAsn1CursorInitPrimary(&PrimaryCursor, pCurCtx->pbCertEncoded, pCurCtx->cbCertEncoded,
+                                        RTErrInfoInitStatic(&StaticErrInfo),
+                                        &g_RTAsn1DefaultAllocator, RTASN1CURSOR_FLAGS_DER, "CurCtx");
+                RTCRX509CERTIFICATE MyCert;
+                int rc2 = RTCrX509Certificate_DecodeAsn1(&PrimaryCursor.Cursor, 0, &MyCert, "Cert");
+                if (RT_SUCCESS(rc2))
+                {
+                    rc2 = RTCrStoreCertAddEncoded(hStore, RTCRCERTCTX_F_ENC_X509_DER | RTCRCERTCTX_F_ADD_IF_NOT_FOUND,
+                                                  pCurCtx->pbCertEncoded, pCurCtx->cbCertEncoded,
+                                                  RTErrInfoInitStatic(&StaticErrInfo));
+                    RTCrX509Certificate_Delete(&MyCert);
+                }
+                if (RT_FAILURE(rc2))
+                {
+                    if (RTErrInfoIsSet(&StaticErrInfo.Core))
+                        RTErrInfoAddF(pErrInfo, -rc2, "  %s", StaticErrInfo.Core.pszMsg);
+                    else
+                        RTErrInfoAddF(pErrInfo, -rc2, "  %Rrc adding cert", rc2);
+                    rc = -rc2;
+                }
+            }
+        }
+        pfnCloseStore(hNativeStore, CERT_CLOSE_STORE_CHECK_FLAG);
+    }
+    else
+    {
+        DWORD uLastErr = GetLastError();
+        if (uLastErr != ERROR_FILE_NOT_FOUND)
+            rc = RTErrInfoAddF(pErrInfo, -RTErrConvertFromWin32(uLastErr),
+                               " CertOpenStore(%#x,'%ls') failed: %u", fStore, pwszStoreName);
+    }
+    return rc;
+}
+
+
+
+RTDECL(int) RTCrStoreCreateSnapshotById(PRTCRSTORE phStore, RTCRSTOREID enmStoreId, PRTERRINFO pErrInfo)
+{
+    AssertReturn(enmStoreId > RTCRSTOREID_INVALID && enmStoreId < RTCRSTOREID_END, VERR_INVALID_PARAMETER);
+
+    /*
+     * Create an empty in-memory store.
+     */
+    RTCRSTORE hStore;
+    int rc = RTCrStoreCreateInMem(&hStore, 128);
+    if (RT_SUCCESS(rc))
+    {
+        *phStore = hStore;
+
+        /*
+         * Resolve the APIs we need to do this job.
+         */
+        RTLDRMOD hLdrMod;
+        int rc2 = RTLdrLoadSystem("crypt32.dll", false /*NoUnload*/, &hLdrMod);
+        if (RT_SUCCESS(rc2))
+        {
+            PFNCERTOPENSTORE                pfnOpenStore  = NULL;
+            rc2 = RTLdrGetSymbol(hLdrMod, "CertOpenStore", (void **)&pfnOpenStore);
+
+            PFNCERTCLOSESTORE               pfnCloseStore = NULL;
+            if (RT_SUCCESS(rc2))
+                rc2 = RTLdrGetSymbol(hLdrMod, "CertCloseStore", (void **)&pfnCloseStore);
+
+            PFNCERTENUMCERTIFICATESINSTORE  pfnEnumCerts  = NULL;
+            if (RT_SUCCESS(rc2))
+                rc2 = RTLdrGetSymbol(hLdrMod, "CertEnumCertificatesInStore", (void **)&pfnEnumCerts);
+            if (RT_SUCCESS(rc2))
+            {
+                /*
+                 * Do the work.
+                 */
+                DWORD fStore = CERT_SYSTEM_STORE_CURRENT_USER;
+                switch (enmStoreId)
+                {
+                    case RTCRSTOREID_SYSTEM_TRUSTED_CAS_AND_CERTIFICATES:
+                    case RTCRSTOREID_SYSTEM_INTERMEDIATE_CAS:
+                        fStore = CERT_SYSTEM_STORE_LOCAL_MACHINE;
+                        RT_FALL_THRU();
+                    case RTCRSTOREID_USER_TRUSTED_CAS_AND_CERTIFICATES:
+                    case RTCRSTOREID_USER_INTERMEDIATE_CAS:
+                    {
+                        /** @todo CA and MY in s_apwszRootStores are _very_ questionable!!! However,
+                         * curl may need them  to work correct and it doesn't seem to have any
+                         * intermediate ca file. :/ */
+                        static PCRTUTF16 const s_apwszRootStores[] = { L"AuthRoot", L"CA", L"MY", L"Root" };
+                        static PCRTUTF16 const s_apwszIntermediateStores[] = { L"CA", L"MY" };
+                        PCRTUTF16 const *papwszStores = s_apwszRootStores;
+                        uint32_t         cStores      = RT_ELEMENTS(s_apwszRootStores);
+                        if (enmStoreId == RTCRSTOREID_USER_INTERMEDIATE_CAS || enmStoreId == RTCRSTOREID_SYSTEM_INTERMEDIATE_CAS)
+                        {
+                            papwszStores = s_apwszIntermediateStores;
+                            cStores      = RT_ELEMENTS(s_apwszIntermediateStores);
+                        }
+
+                        for (uint32_t i = 0; i < cStores; i++)
+                            rc = rtCrStoreAddCertsFromNative(hStore, fStore, papwszStores[i], pfnOpenStore, pfnCloseStore,
+                                                             pfnEnumCerts, rc, pErrInfo);
+                        break;
+                    }
+
+                    default:
+                        AssertFailed(); /* implement me */
+                }
+            }
+            else
+                rc = RTErrInfoSetF(pErrInfo, -rc2, "Error resolving crypt32.dll APIs");
+            RTLdrClose(hLdrMod);
+        }
+        else
+            rc = RTErrInfoSetF(pErrInfo, -rc2, "Error loading crypt32.dll");
+    }
+    else
+        RTErrInfoSet(pErrInfo, rc, "RTCrStoreCreateInMem failed");
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTCrStoreCreateSnapshotById);
+
diff --git a/src/VBox/Runtime/r3/win/RTFileQuerySectorSize-win.cpp b/src/VBox/Runtime/r3/win/RTFileQuerySectorSize-win.cpp
new file mode 100644
index 00000000..97a38271
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTFileQuerySectorSize-win.cpp
@@ -0,0 +1,71 @@
+/* $Id: RTFileQuerySectorSize-win.cpp $ */
+/** @file
+ * IPRT - RTFileQuerySectorSize, Windows.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/file.h>
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+
+#include <iprt/win/windows.h>
+
+
+
+RTDECL(int) RTFileQuerySectorSize(RTFILE hFile, uint32_t *pcbSector)
+{
+    AssertPtrReturn(pcbSector, VERR_INVALID_PARAMETER);
+
+    DISK_GEOMETRY DriveGeo;
+    RT_ZERO(DriveGeo);
+    DWORD cbDriveGeo = 0;
+    if (DeviceIoControl((HANDLE)RTFileToNative(hFile),
+                        IOCTL_DISK_GET_DRIVE_GEOMETRY, NULL, 0,
+                        &DriveGeo, sizeof(DriveGeo), &cbDriveGeo, NULL))
+    {
+        AssertReturn(DriveGeo.BytesPerSector > 0, VERR_INVALID_PARAMETER);
+        *pcbSector = DriveGeo.BytesPerSector;
+        return VINF_SUCCESS;
+    }
+    int rc = RTErrConvertFromWin32(GetLastError());
+    AssertMsg(rc == VERR_IO_NOT_READY, ("%d / %Rrc\n", GetLastError(), rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTHandleGetStandard-win.cpp b/src/VBox/Runtime/r3/win/RTHandleGetStandard-win.cpp
new file mode 100644
index 00000000..c0b7f780
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTHandleGetStandard-win.cpp
@@ -0,0 +1,143 @@
+/* $Id: RTHandleGetStandard-win.cpp $ */
+/** @file
+ * IPRT - RTHandleGetStandard, Windows.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/handle.h>
+
+#include <iprt/file.h>
+#include <iprt/pipe.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+
+#include <iprt/win/windows.h>
+
+#include "internal/socket.h"            /* (Needs Windows.h.) */
+#include "internal-r3-win.h"            /* (Needs Windows.h.) */
+
+
+RTDECL(int) RTHandleGetStandard(RTHANDLESTD enmStdHandle, bool fLeaveOpen, PRTHANDLE ph)
+{
+    /*
+     * Validate and convert input.
+     */
+    AssertPtrReturn(ph, VERR_INVALID_POINTER);
+    DWORD dwStdHandle;
+    switch (enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:  dwStdHandle = STD_INPUT_HANDLE; break;
+        case RTHANDLESTD_OUTPUT: dwStdHandle = STD_OUTPUT_HANDLE; break;
+        case RTHANDLESTD_ERROR:  dwStdHandle = STD_ERROR_HANDLE; break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    /*
+     * Is the requested descriptor valid and which IPRT handle type does it
+     * best map on to?
+     */
+    HANDLE hNative = GetStdHandle(dwStdHandle);
+    if (hNative == INVALID_HANDLE_VALUE)
+        return RTErrConvertFromWin32(GetLastError());
+
+    DWORD dwInfo = 0;
+    if (g_pfnGetHandleInformation && !g_pfnGetHandleInformation(hNative, &dwInfo))
+        return RTErrConvertFromWin32(GetLastError());
+    bool const fInherit = RT_BOOL(dwInfo & HANDLE_FLAG_INHERIT);
+
+    SetLastError(NO_ERROR);
+    RTHANDLE h;
+    DWORD    dwType = GetFileType(hNative);
+    switch (dwType & ~FILE_TYPE_REMOTE)
+    {
+        case FILE_TYPE_UNKNOWN:
+            if (GetLastError() != NO_ERROR)
+                return RTErrConvertFromWin32(GetLastError());
+            RT_FALL_THROUGH();
+        default:
+        case FILE_TYPE_CHAR:
+        case FILE_TYPE_DISK:
+            h.enmType = RTHANDLETYPE_FILE;
+            break;
+
+        case FILE_TYPE_PIPE:
+        {
+            DWORD cMaxInstances;
+            DWORD fInfo;
+            if (!GetNamedPipeInfo(hNative, &fInfo, NULL, NULL, &cMaxInstances))
+                h.enmType = RTHANDLETYPE_SOCKET;
+            else
+                h.enmType = RTHANDLETYPE_PIPE;
+            break;
+        }
+    }
+
+    /*
+     * Create the IPRT handle.
+     */
+    int rc;
+    switch (h.enmType)
+    {
+        case RTHANDLETYPE_FILE:
+            /** @todo fLeaveOpen   */
+            rc = RTFileFromNative(&h.u.hFile, (RTHCUINTPTR)hNative);
+            break;
+
+        case RTHANDLETYPE_PIPE:
+            rc = RTPipeFromNative(&h.u.hPipe, (RTHCUINTPTR)hNative,
+                                    (enmStdHandle == RTHANDLESTD_INPUT ? RTPIPE_N_READ : RTPIPE_N_WRITE)
+                                  | (fInherit ? RTPIPE_N_INHERIT : 0)
+                                  | (fLeaveOpen ? RTPIPE_N_LEAVE_OPEN : 0));
+            break;
+
+        case RTHANDLETYPE_SOCKET:
+            rc = rtSocketCreateForNative(&h.u.hSocket, (RTHCUINTPTR)hNative, fLeaveOpen);
+            break;
+
+        default: /* shut up gcc */
+            return VERR_INTERNAL_ERROR;
+    }
+
+    if (RT_SUCCESS(rc))
+        *ph = h;
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTLocaleQueryNormalizedBaseLocaleName-win.cpp b/src/VBox/Runtime/r3/win/RTLocaleQueryNormalizedBaseLocaleName-win.cpp
new file mode 100644
index 00000000..10efd342
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTLocaleQueryNormalizedBaseLocaleName-win.cpp
@@ -0,0 +1,116 @@
+/* $Id: RTLocaleQueryNormalizedBaseLocaleName-win.cpp $ */
+/** @file
+ * IPRT - RTLocaleQueryNormalizedBaseLocaleName, ring-3, Windows.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/windows.h>
+
+#include <iprt/locale.h>
+#include "internal/iprt.h"
+
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+
+RTDECL(int) RTLocaleQueryNormalizedBaseLocaleName(char *pszName, size_t cbName)
+{
+    /*
+     * Note! This part is duplicate of r3/generic/RTLocaleQueryNormalizedBaseLocaleName-r3-generic.cpp!
+     */
+    char szLocale[_1K];
+    int rc = RTLocaleQueryLocaleName(szLocale, sizeof(szLocale));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * May return some complicated "LC_XXX=yyy;LC.." sequence if
+         * partially set (like IPRT does).  Try get xx_YY sequence first
+         * because 'C' or 'POSIX' may be LC_xxx variants that haven't been
+         * set yet.
+         *
+         * ASSUMES complicated locale mangling is done in a certain way...
+         */
+        const char *pszLocale = strchr(szLocale, '=');
+        if (!pszLocale)
+            pszLocale = szLocale;
+        else
+            pszLocale++;
+        bool fSeenC = false;
+        bool fSeenPOSIX = false;
+        do
+        {
+            const char *pszEnd = strchr(pszLocale, ';');
+
+            if (   RTLOCALE_IS_LANGUAGE2_UNDERSCORE_COUNTRY2(pszLocale)
+                && (   pszLocale[5] == '\0'
+                    || RT_C_IS_PUNCT(pszLocale[5])) )
+                return RTStrCopyEx(pszName, cbName, pszLocale, 5);
+
+            if (   pszLocale[0] == 'C'
+                && (   pszLocale[1] == '\0'
+                    || RT_C_IS_PUNCT(pszLocale[1])) )
+                fSeenC = true;
+            else if (   strncmp(pszLocale, "POSIX", 5) == 0
+                     && (   pszLocale[5] == '\0'
+                        || RT_C_IS_PUNCT(pszLocale[5])) )
+                fSeenPOSIX = true;
+
+            /* advance */
+            pszLocale = pszEnd ? strchr(pszEnd + 1, '=') : NULL;
+        } while (pszLocale++);
+
+        if (fSeenC || fSeenPOSIX)
+            return RTStrCopy(pszName, cbName, "C"); /* C and POSIX should be identical IIRC, so keep it simple. */
+
+        rc = VERR_NOT_AVAILABLE;
+    }
+
+    /*
+     * Fallback.
+     */
+    if (   GetLocaleInfoA(GetUserDefaultLCID(), LOCALE_SISO639LANGNAME, szLocale, sizeof(szLocale)) == 3
+        && GetLocaleInfoA(GetUserDefaultLCID(), LOCALE_SISO3166CTRYNAME, &szLocale[3], sizeof(szLocale) - 4) == 3)
+    {
+        szLocale[2] = '_';
+        Assert(RTLOCALE_IS_LANGUAGE2_UNDERSCORE_COUNTRY2(szLocale));
+        return RTStrCopy(pszName, cbName, szLocale);
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTLocaleQueryUserCountryCode-win.cpp b/src/VBox/Runtime/r3/win/RTLocaleQueryUserCountryCode-win.cpp
new file mode 100644
index 00000000..a95b1c22
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTLocaleQueryUserCountryCode-win.cpp
@@ -0,0 +1,129 @@
+/* $Id: RTLocaleQueryUserCountryCode-win.cpp $ */
+/** @file
+ * IPRT - RTLocaleQueryUserCountryCode, ring-3, Windows.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/windows.h>
+
+#include <iprt/locale.h>
+#include "internal/iprt.h"
+
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef GEOID (WINAPI *PFNGETUSERGEOID)(GEOCLASS);
+typedef INT   (WINAPI *PFNGETGEOINFOW)(GEOID,GEOTYPE,LPWSTR,INT,LANGID);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Pointer to GetUserGeoID. */
+static PFNGETUSERGEOID  g_pfnGetUserGeoID = NULL;
+/** Pointer to GetGeoInfoW. */
+static PFNGETGEOINFOW   g_pfnGetGeoInfoW = NULL;
+/** Set if we've tried to resolve the APIs. */
+static bool volatile    g_fResolvedApis = false;
+
+
+RTDECL(int) RTLocaleQueryUserCountryCode(char pszCountryCode[3])
+{
+    /*
+     * Get API pointers.
+     */
+    PFNGETUSERGEOID  pfnGetUserGeoID;
+    PFNGETGEOINFOW   pfnGetGeoInfoW;
+    if (g_fResolvedApis)
+    {
+        pfnGetUserGeoID = g_pfnGetUserGeoID;
+        pfnGetGeoInfoW  = g_pfnGetGeoInfoW;
+    }
+    else
+    {
+        pfnGetUserGeoID = (PFNGETUSERGEOID)GetProcAddress(g_hModKernel32, "GetUserGeoID");
+        pfnGetGeoInfoW  = (PFNGETGEOINFOW)GetProcAddress(g_hModKernel32, "GetGeoInfoW");
+        g_pfnGetUserGeoID = pfnGetUserGeoID;
+        g_pfnGetGeoInfoW  = pfnGetGeoInfoW;
+        g_fResolvedApis   = true;
+    }
+
+    int rc;
+    if (   pfnGetGeoInfoW
+        && pfnGetUserGeoID)
+    {
+        /*
+         * Call the API and retrieve the two letter ISO country code.
+         */
+        GEOID idGeo = pfnGetUserGeoID(GEOCLASS_NATION);
+        if (idGeo != GEOID_NOT_AVAILABLE)
+        {
+            RTUTF16 wszName[16];
+            RT_ZERO(wszName);
+            DWORD cwcReturned = pfnGetGeoInfoW(idGeo, GEO_ISO2, wszName, RT_ELEMENTS(wszName), LOCALE_NEUTRAL);
+            if (   cwcReturned >= 2
+                && cwcReturned <= 3
+                && wszName[2] == '\0'
+                && wszName[1] != '\0'
+                && RT_C_IS_ALPHA(wszName[1])
+                && wszName[0] != '\0'
+                && RT_C_IS_ALPHA(wszName[0]) )
+            {
+                pszCountryCode[0] = RT_C_TO_UPPER(wszName[0]);
+                pszCountryCode[1] = RT_C_TO_UPPER(wszName[1]);
+                pszCountryCode[2] = '\0';
+                return VINF_SUCCESS;
+            }
+            AssertMsgFailed(("cwcReturned=%d err=%u wszName='%.16ls'\n", cwcReturned, GetLastError(), wszName));
+        }
+        rc = VERR_NOT_AVAILABLE;
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    pszCountryCode[0] = 'Z';
+    pszCountryCode[1] = 'Z';
+    pszCountryCode[2] = '\0';
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTLogWriteDebugger-win.cpp b/src/VBox/Runtime/r3/win/RTLogWriteDebugger-win.cpp
new file mode 100644
index 00000000..27d3bc05
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTLogWriteDebugger-win.cpp
@@ -0,0 +1,54 @@
+/* $Id: RTLogWriteDebugger-win.cpp $ */
+/** @file
+ * IPRT - Log To Debugger, Win32.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/windows.h>
+
+#include <iprt/log.h>
+#include <iprt/assert.h>
+
+
+RTDECL(void) RTLogWriteDebugger(const char *pch, size_t cb)
+{
+    if (pch[cb] != '\0')
+        AssertBreakpoint();
+    OutputDebugStringA(pch);
+    return;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTSystemFirmware-win.cpp b/src/VBox/Runtime/r3/win/RTSystemFirmware-win.cpp
new file mode 100644
index 00000000..d00dacb1
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTSystemFirmware-win.cpp
@@ -0,0 +1,223 @@
+/* $Id: RTSystemFirmware-win.cpp $ */
+/** @file
+ * IPRT - System firmware information, Win32.
+ */
+
+/*
+ * Copyright (C) 2019-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/system.h>
+
+#include <iprt/nt/nt-and-windows.h>
+#include <WinSDKVer.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/ldr.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+#if _WIN32_MAXVER < 0x0602 /* Windows 7 or older, supply missing GetFirmwareType bits. */
+typedef enum _FIRMWARE_TYPE
+{
+    FirmwareTypeUnknown,
+    FirmwareTypeBios,
+    FirmwareTypeUefi,
+    FirmwareTypeMax
+} FIRMWARE_TYPE;
+typedef FIRMWARE_TYPE *PFIRMWARE_TYPE;
+WINBASEAPI BOOL WINAPI GetFirmwareType(PFIRMWARE_TYPE);
+#endif
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Defines the UEFI Globals UUID. */
+#define VBOX_UEFI_UUID_GLOBALS L"{8BE4DF61-93CA-11D2-AA0D-00E098032B8C}"
+/** Defines an UEFI dummy UUID, see MSDN docs of the API. */
+#define VBOX_UEFI_UUID_DUMMY   L"{00000000-0000-0000-0000-000000000000}"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static volatile bool                              g_fResolvedApis = false;
+static decltype(GetFirmwareType)                 *g_pfnGetFirmwareType;
+static decltype(GetFirmwareEnvironmentVariableW) *g_pfnGetFirmwareEnvironmentVariableW;
+
+
+static void rtSystemFirmwareResolveApis(void)
+{
+    FARPROC pfnTmp1 = GetProcAddress(g_hModKernel32, "GetFirmwareType");
+    FARPROC pfnTmp2 = GetProcAddress(g_hModKernel32, "GetFirmwareEnvironmentVariableW");
+    ASMCompilerBarrier(); /* paranoia^2 */
+
+    g_pfnGetFirmwareType                 = (decltype(GetFirmwareType) *)pfnTmp1;
+    g_pfnGetFirmwareEnvironmentVariableW = (decltype(GetFirmwareEnvironmentVariableW) *)pfnTmp2;
+    ASMAtomicWriteBool(&g_fResolvedApis, true);
+}
+
+
+static int rtSystemFirmwareGetPrivileges(LPCTSTR pcszPrivilege)
+{
+    HANDLE hToken;
+    BOOL fRc = OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken);
+    if (!fRc)
+        return RTErrConvertFromWin32(GetLastError());
+
+    int rc = VINF_SUCCESS;
+
+    TOKEN_PRIVILEGES tokenPriv;
+    fRc = LookupPrivilegeValue(NULL, pcszPrivilege, &tokenPriv.Privileges[0].Luid);
+    if (fRc)
+    {
+        tokenPriv.PrivilegeCount = 1;
+        tokenPriv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+        fRc = AdjustTokenPrivileges(hToken, FALSE, &tokenPriv, 0, (PTOKEN_PRIVILEGES)NULL, 0);
+        if (!fRc)
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    CloseHandle(hToken);
+
+    return rc;
+}
+
+
+RTDECL(int) RTSystemQueryFirmwareType(PRTSYSFWTYPE penmFirmwareType)
+{
+    AssertPtrReturn(penmFirmwareType, VERR_INVALID_POINTER);
+
+    if (!g_fResolvedApis)
+        rtSystemFirmwareResolveApis();
+
+    *penmFirmwareType = RTSYSFWTYPE_INVALID;
+    int rc = VERR_NOT_SUPPORTED;
+
+    /* GetFirmwareType is Windows 8 and later. */
+    if (g_pfnGetFirmwareType)
+    {
+        FIRMWARE_TYPE enmWinFwType;
+        if (g_pfnGetFirmwareType(&enmWinFwType))
+        {
+            switch (enmWinFwType)
+            {
+                case FirmwareTypeBios:
+                    *penmFirmwareType = RTSYSFWTYPE_BIOS;
+                    break;
+                case FirmwareTypeUefi:
+                    *penmFirmwareType = RTSYSFWTYPE_UEFI;
+                    break;
+                default:
+                    *penmFirmwareType = RTSYSFWTYPE_UNKNOWN;
+                    AssertMsgFailed(("%d\n", enmWinFwType));
+                    break;
+            }
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    /* GetFirmwareEnvironmentVariableW is XP and later. */
+    else if (g_pfnGetFirmwareEnvironmentVariableW)
+    {
+        rtSystemFirmwareGetPrivileges(SE_SYSTEM_ENVIRONMENT_NAME);
+
+        /* On a non-UEFI system (or such a system in legacy boot mode), we will get
+           back ERROR_INVALID_FUNCTION when querying any firmware variable.  While on a
+           UEFI system we'll typically get ERROR_ACCESS_DENIED or similar as the dummy
+           is a non-exising dummy namespace.  See the API docs. */
+        SetLastError(0);
+        uint8_t abWhatever[64];
+        DWORD cbRet = g_pfnGetFirmwareEnvironmentVariableW(L"", VBOX_UEFI_UUID_DUMMY, abWhatever, sizeof(abWhatever));
+        DWORD dwErr = GetLastError();
+        *penmFirmwareType = cbRet != 0 || dwErr != ERROR_INVALID_FUNCTION ? RTSYSFWTYPE_UEFI : RTSYSFWTYPE_BIOS;
+        rc = VINF_SUCCESS;
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTSystemQueryFirmwareBoolean(RTSYSFWBOOL enmBoolean, bool *pfValue)
+{
+    *pfValue = false;
+
+    /*
+     * Translate the enmBoolean to a name:
+     */
+    const wchar_t *pwszName = NULL;
+    switch (enmBoolean)
+    {
+        case RTSYSFWBOOL_SECURE_BOOT:
+            pwszName = L"SecureBoot";
+            break;
+
+        default:
+            AssertReturn(enmBoolean > RTSYSFWBOOL_INVALID && enmBoolean < RTSYSFWBOOL_END, VERR_INVALID_PARAMETER);
+            return VERR_SYS_UNSUPPORTED_FIRMWARE_PROPERTY;
+    }
+
+    /*
+     * Do the query.
+     * Note! This will typically fail with access denied unless we're in an elevated process.
+     */
+    if (!g_pfnGetFirmwareEnvironmentVariableW)
+        return VERR_NOT_SUPPORTED;
+    rtSystemFirmwareGetPrivileges(SE_SYSTEM_ENVIRONMENT_NAME);
+
+    uint8_t bValue = 0;
+    DWORD cbRet = g_pfnGetFirmwareEnvironmentVariableW(pwszName, VBOX_UEFI_UUID_GLOBALS, &bValue, sizeof(bValue));
+    *pfValue = cbRet != 0 && bValue != 0;
+    if (cbRet != 0)
+        return VINF_SUCCESS;
+    DWORD dwErr = GetLastError();
+    if (   dwErr == ERROR_INVALID_FUNCTION
+        || dwErr == ERROR_ENVVAR_NOT_FOUND)
+        return VINF_SUCCESS;
+    return RTErrConvertFromWin32(dwErr);
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTSystemQueryDmiString-win.cpp b/src/VBox/Runtime/r3/win/RTSystemQueryDmiString-win.cpp
new file mode 100644
index 00000000..bd9c97e5
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTSystemQueryDmiString-win.cpp
@@ -0,0 +1,269 @@
+/* $Id: RTSystemQueryDmiString-win.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryDmiString, windows ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define _WIN32_DCOM
+#include <iprt/win/windows.h>
+#include <WbemCli.h>
+
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+
+/**
+ * Initialize COM.
+ *
+ * @returns COM status code.
+ */
+static HRESULT rtSystemDmiWinInitialize(void)
+{
+    HRESULT hrc = CoInitializeEx(0, COINIT_MULTITHREADED);
+    if (SUCCEEDED(hrc))
+    {
+        hrc = CoInitializeSecurity(NULL,
+                                   -1,                          /* COM authentication. */
+                                   NULL,                        /* Which authentication services. */
+                                   NULL,                        /* Reserved. */
+                                   RPC_C_AUTHN_LEVEL_DEFAULT,   /* Default authentication. */
+                                   RPC_C_IMP_LEVEL_IMPERSONATE, /* Default impersonation. */
+                                   NULL,                        /* Authentication info. */
+                                   EOAC_NONE,                   /* Additional capabilities. */
+                                   NULL);                       /* Reserved. */
+        if (hrc == RPC_E_TOO_LATE)
+            hrc = S_OK;
+        else if (FAILED(hrc))
+            CoUninitialize();
+    }
+    return hrc;
+}
+
+
+/**
+ * Undo what rtSystemDmiWinInitialize did.
+ */
+static void rtSystemDmiWinTerminate(void)
+{
+    CoUninitialize();
+}
+
+
+/**
+ * Convert a UTF-8 string to a BSTR.
+ *
+ * @returns BSTR pointer.
+ * @param   psz                 The UTF-8 string.
+ */
+static BSTR rtSystemWinBstrFromUtf8(const char *psz)
+{
+    PRTUTF16 pwsz = NULL;
+    int rc = RTStrToUtf16(psz, &pwsz);
+    if (RT_FAILURE(rc))
+        return NULL;
+    BSTR pBStr = SysAllocString((const OLECHAR *)pwsz);
+    RTUtf16Free(pwsz);
+    return pBStr;
+}
+
+
+/**
+ * Connect to the DMI server.
+ *
+ * @returns COM status code.
+ * @param   pLocator            The locator.
+ * @param   pszServer           The server name.
+ * @param   ppServices          Where to return the services interface.
+ */
+static HRESULT rtSystemDmiWinConnectToServer(IWbemLocator *pLocator, const char *pszServer, IWbemServices **ppServices)
+{
+    AssertPtr(pLocator);
+    AssertPtrNull(pszServer);
+    AssertPtr(ppServices);
+
+    BSTR pBStrServer = rtSystemWinBstrFromUtf8(pszServer);
+    if (!pBStrServer)
+        return E_OUTOFMEMORY;
+
+    HRESULT hrc = pLocator->ConnectServer(pBStrServer,
+                                          NULL,
+                                          NULL,
+                                          0,
+                                          NULL,
+                                          0,
+                                          0,
+                                          ppServices);
+    if (SUCCEEDED(hrc))
+    {
+        hrc = CoSetProxyBlanket(*ppServices,
+                                RPC_C_AUTHN_WINNT,
+                                RPC_C_AUTHZ_NONE,
+                                NULL,
+                                RPC_C_AUTHN_LEVEL_CALL,
+                                RPC_C_IMP_LEVEL_IMPERSONATE,
+                                NULL,
+                                EOAC_NONE);
+        if (FAILED(hrc))
+            (*ppServices)->Release();
+    }
+    SysFreeString(pBStrServer);
+    return hrc;
+}
+
+
+RTDECL(int) RTSystemQueryDmiString(RTSYSDMISTR enmString, char *pszBuf, size_t cbBuf)
+{
+    AssertPtrReturn(pszBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbBuf > 0, VERR_INVALID_PARAMETER);
+    *pszBuf = '\0';
+    AssertReturn(enmString > RTSYSDMISTR_INVALID && enmString < RTSYSDMISTR_END, VERR_INVALID_PARAMETER);
+
+    /*
+     * Figure the property name before we start.
+     */
+    const char *pszPropName;
+    switch (enmString)
+    {
+        case RTSYSDMISTR_PRODUCT_NAME:      pszPropName = "Name"; break;
+        case RTSYSDMISTR_PRODUCT_VERSION:   pszPropName = "Version"; break;
+        case RTSYSDMISTR_PRODUCT_UUID:      pszPropName = "UUID"; break;
+        case RTSYSDMISTR_PRODUCT_SERIAL:    pszPropName = "IdentifyingNumber"; break;
+        case RTSYSDMISTR_MANUFACTURER:      pszPropName = "Vendor"; break;
+
+        default:
+            return VERR_NOT_SUPPORTED;
+    }
+
+    /*
+     * Before we do anything with COM, we have to initialize it.
+     */
+    bool fUninit = true;
+    HRESULT hrc = rtSystemDmiWinInitialize();
+    if (hrc == RPC_E_CHANGED_MODE)
+        fUninit = false;  /* don't fail if already initialized */
+    else if (FAILED(hrc))
+        return VERR_NOT_SUPPORTED;
+
+    int rc = VERR_NOT_SUPPORTED;
+    BSTR pBstrPropName = rtSystemWinBstrFromUtf8(pszPropName);
+    if (pBstrPropName)
+    {
+        /*
+         * Instantiate the IWbemLocator, whatever that is and connect to the
+         * DMI serve.
+         */
+        IWbemLocator *pLoc;
+        hrc = CoCreateInstance(CLSID_WbemLocator,
+                               0,
+                               CLSCTX_INPROC_SERVER,
+                               IID_IWbemLocator,
+                               (LPVOID *)&pLoc);
+        if (SUCCEEDED(hrc))
+        {
+            IWbemServices *pServices;
+            hrc = rtSystemDmiWinConnectToServer(pLoc, "ROOT\\CIMV2", &pServices);
+            if (SUCCEEDED(hrc))
+            {
+                /*
+                 * Enumerate whatever it is we're looking at and try get
+                 * the desired property.
+                 */
+                BSTR pBstrFilter = rtSystemWinBstrFromUtf8("Win32_ComputerSystemProduct");
+                if (pBstrFilter)
+                {
+                    IEnumWbemClassObject *pEnum;
+                    hrc = pServices->CreateInstanceEnum(pBstrFilter, 0, NULL, &pEnum);
+                    if (SUCCEEDED(hrc))
+                    {
+                        do
+                        {
+                            IWbemClassObject *pObj;
+                            ULONG cObjRet;
+                            hrc = pEnum->Next(WBEM_INFINITE, 1, &pObj, &cObjRet);
+                            if (   SUCCEEDED(hrc)
+                                && cObjRet >= 1)
+                            {
+                                VARIANT Var;
+                                VariantInit(&Var);
+                                hrc = pObj->Get(pBstrPropName, 0, &Var, 0, 0);
+                                if (   SUCCEEDED(hrc)
+                                    && V_VT(&Var) == VT_BSTR)
+                                {
+                                    /*
+                                     * Convert the BSTR to UTF-8 and copy it
+                                     * into the return buffer.
+                                     */
+                                    char *pszValue;
+                                    rc = RTUtf16ToUtf8(Var.bstrVal, &pszValue);
+                                    if (RT_SUCCESS(rc))
+                                    {
+                                        rc = RTStrCopy(pszBuf, cbBuf, pszValue);
+                                        RTStrFree(pszValue);
+                                        hrc = WBEM_S_FALSE;
+                                    }
+                                }
+                                VariantClear(&Var);
+                                pObj->Release();
+                            }
+                        } while (hrc != WBEM_S_FALSE);
+
+                        pEnum->Release();
+                    }
+                    SysFreeString(pBstrFilter);
+                }
+                else
+                    hrc = E_OUTOFMEMORY;
+                pServices->Release();
+            }
+            pLoc->Release();
+        }
+        SysFreeString(pBstrPropName);
+    }
+    else
+        hrc = E_OUTOFMEMORY;
+    if (fUninit)
+        rtSystemDmiWinTerminate();
+    if (FAILED(hrc) && rc == VERR_NOT_SUPPORTED)
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTSystemQueryOSInfo-win.cpp b/src/VBox/Runtime/r3/win/RTSystemQueryOSInfo-win.cpp
new file mode 100644
index 00000000..56688e42
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTSystemQueryOSInfo-win.cpp
@@ -0,0 +1,358 @@
+/* $Id: RTSystemQueryOSInfo-win.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryOSInfo, generic stub.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/win/windows.h>
+#include <WinUser.h>
+
+#include "internal-r3-win.h"
+#include <iprt/system.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * These are the PRODUCT_* defines found in the Vista Platform SDK and returned
+ * by GetProductInfo().
+ *
+ * We define them ourselves because we don't necessarily have any Vista PSDK around.
+ */
+typedef enum RTWINPRODTYPE
+{
+    kRTWinProdType_UNDEFINED                    = 0x00000000,  ///< An unknown product
+    kRTWinProdType_BUSINESS                     = 0x00000006,  ///< Business Edition
+    kRTWinProdType_BUSINESS_N                   = 0x00000010,  ///< Business Edition
+    kRTWinProdType_CLUSTER_SERVER               = 0x00000012,  ///< Cluster Server Edition
+    kRTWinProdType_DATACENTER_SERVER            = 0x00000008,  ///< Server Datacenter Edition (full installation)
+    kRTWinProdType_DATACENTER_SERVER_CORE       = 0x0000000C,  ///< Server Datacenter Edition (core installation)
+    kRTWinProdType_ENTERPRISE                   = 0x00000004,  ///< Enterprise Edition
+    kRTWinProdType_ENTERPRISE_N                 = 0x0000001B,  ///< Enterprise Edition
+    kRTWinProdType_ENTERPRISE_SERVER            = 0x0000000A,  ///< Server Enterprise Edition (full installation)
+    kRTWinProdType_ENTERPRISE_SERVER_CORE       = 0x0000000E,  ///< Server Enterprise Edition (core installation)
+    kRTWinProdType_ENTERPRISE_SERVER_IA64       = 0x0000000F,  ///< Server Enterprise Edition for Itanium-based Systems
+    kRTWinProdType_HOME_BASIC                   = 0x00000002,  ///< Home Basic Edition
+    kRTWinProdType_HOME_BASIC_N                 = 0x00000005,  ///< Home Basic Edition
+    kRTWinProdType_HOME_PREMIUM                 = 0x00000003,  ///< Home Premium Edition
+    kRTWinProdType_HOME_PREMIUM_N               = 0x0000001A,  ///< Home Premium Edition
+    kRTWinProdType_HOME_SERVER                  = 0x00000013,  ///< Home Server Edition
+    kRTWinProdType_SERVER_FOR_SMALLBUSINESS     = 0x00000018,  ///< Server for Small Business Edition
+    kRTWinProdType_SMALLBUSINESS_SERVER         = 0x00000009,  ///< Small Business Server
+    kRTWinProdType_SMALLBUSINESS_SERVER_PREMIUM = 0x00000019,  ///< Small Business Server Premium Edition
+    kRTWinProdType_STANDARD_SERVER              = 0x00000007,  ///< Server Standard Edition (full installation)
+    kRTWinProdType_STANDARD_SERVER_CORE         = 0x0000000D,  ///< Server Standard Edition (core installation)
+    kRTWinProdType_STARTER                      = 0x0000000B,  ///< Starter Edition
+    kRTWinProdType_STORAGE_ENTERPRISE_SERVER    = 0x00000017,  ///< Storage Server Enterprise Edition
+    kRTWinProdType_STORAGE_EXPRESS_SERVER       = 0x00000014,  ///< Storage Server Express Edition
+    kRTWinProdType_STORAGE_STANDARD_SERVER      = 0x00000015,  ///< Storage Server Standard Edition
+    kRTWinProdType_STORAGE_WORKGROUP_SERVER     = 0x00000016,  ///< Storage Server Workgroup Edition
+    kRTWinProdType_ULTIMATE                     = 0x00000001,  ///< Ultimate Edition
+    kRTWinProdType_ULTIMATE_N                   = 0x0000001C,  ///< Ultimate Edition
+    kRTWinProdType_WEB_SERVER                   = 0x00000011,  ///< Web Server Edition (full)
+    kRTWinProdType_WEB_SERVER_CORE              = 0x0000001D   ///< Web Server Edition (core)
+} RTWINPRODTYPE;
+
+
+/**
+ * Wrapper around the GetProductInfo API.
+ *
+ * @returns The vista type.
+ */
+static RTWINPRODTYPE rtSystemWinGetProductInfo(DWORD dwOSMajorVersion, DWORD dwOSMinorVersion, DWORD dwSpMajorVersion, DWORD dwSpMinorVersion)
+{
+    BOOL (WINAPI *pfnGetProductInfo)(DWORD, DWORD, DWORD, DWORD, PDWORD);
+    pfnGetProductInfo = (BOOL (WINAPI *)(DWORD, DWORD, DWORD, DWORD, PDWORD))GetProcAddress(GetModuleHandle("kernel32.dll"),
+                                                                                            "GetProductInfo");
+    if (pfnGetProductInfo)
+    {
+        DWORD dwProductType = kRTWinProdType_UNDEFINED;
+        if (pfnGetProductInfo(dwOSMajorVersion, dwOSMinorVersion, dwSpMajorVersion, dwSpMinorVersion, &dwProductType))
+            return (RTWINPRODTYPE)dwProductType;
+    }
+    return kRTWinProdType_UNDEFINED;
+}
+
+
+
+/**
+ * Appends the product type if available (Vista & 2003 only for some reason).
+ *
+ * @param   pszTmp      The buffer.
+ * @param   cbTmp       The buffer size.
+ */
+static void rtSystemWinAppendProductType(char *pszTmp, size_t cbTmp)
+{
+    RTWINPRODTYPE enmVistaType = rtSystemWinGetProductInfo(6, 0, 0, 0);
+    switch (enmVistaType)
+    {
+        case kRTWinProdType_BUSINESS:                       RTStrCat(pszTmp, cbTmp, " Business Edition"); break;
+        case kRTWinProdType_BUSINESS_N:                     RTStrCat(pszTmp, cbTmp, " Business Edition"); break;
+        case kRTWinProdType_CLUSTER_SERVER:                 RTStrCat(pszTmp, cbTmp, " Cluster Server Edition"); break;
+        case kRTWinProdType_DATACENTER_SERVER:              RTStrCat(pszTmp, cbTmp, " Server Datacenter Edition (full installation)"); break;
+        case kRTWinProdType_DATACENTER_SERVER_CORE:         RTStrCat(pszTmp, cbTmp, " Server Datacenter Edition (core installation)"); break;
+        case kRTWinProdType_ENTERPRISE:                     RTStrCat(pszTmp, cbTmp, " Enterprise Edition"); break;
+        case kRTWinProdType_ENTERPRISE_N:                   RTStrCat(pszTmp, cbTmp, " Enterprise Edition"); break;
+        case kRTWinProdType_ENTERPRISE_SERVER:              RTStrCat(pszTmp, cbTmp, " Server Enterprise Edition (full installation)"); break;
+        case kRTWinProdType_ENTERPRISE_SERVER_CORE:         RTStrCat(pszTmp, cbTmp, " Server Enterprise Edition (core installation)"); break;
+        case kRTWinProdType_ENTERPRISE_SERVER_IA64:         RTStrCat(pszTmp, cbTmp, " Server Enterprise Edition for Itanium-based Systems"); break;
+        case kRTWinProdType_HOME_BASIC:                     RTStrCat(pszTmp, cbTmp, " Home Basic Edition"); break;
+        case kRTWinProdType_HOME_BASIC_N:                   RTStrCat(pszTmp, cbTmp, " Home Basic Edition"); break;
+        case kRTWinProdType_HOME_PREMIUM:                   RTStrCat(pszTmp, cbTmp, " Home Premium Edition"); break;
+        case kRTWinProdType_HOME_PREMIUM_N:                 RTStrCat(pszTmp, cbTmp, " Home Premium Edition"); break;
+        case kRTWinProdType_HOME_SERVER:                    RTStrCat(pszTmp, cbTmp, " Home Server Edition"); break;
+        case kRTWinProdType_SERVER_FOR_SMALLBUSINESS:       RTStrCat(pszTmp, cbTmp, " Server for Small Business Edition"); break;
+        case kRTWinProdType_SMALLBUSINESS_SERVER:           RTStrCat(pszTmp, cbTmp, " Small Business Server"); break;
+        case kRTWinProdType_SMALLBUSINESS_SERVER_PREMIUM:   RTStrCat(pszTmp, cbTmp, " Small Business Server Premium Edition"); break;
+        case kRTWinProdType_STANDARD_SERVER:                RTStrCat(pszTmp, cbTmp, " Server Standard Edition (full installation)"); break;
+        case kRTWinProdType_STANDARD_SERVER_CORE:           RTStrCat(pszTmp, cbTmp, " Server Standard Edition (core installation)"); break;
+        case kRTWinProdType_STARTER:                        RTStrCat(pszTmp, cbTmp, " Starter Edition"); break;
+        case kRTWinProdType_STORAGE_ENTERPRISE_SERVER:      RTStrCat(pszTmp, cbTmp, " Storage Server Enterprise Edition"); break;
+        case kRTWinProdType_STORAGE_EXPRESS_SERVER:         RTStrCat(pszTmp, cbTmp, " Storage Server Express Edition"); break;
+        case kRTWinProdType_STORAGE_STANDARD_SERVER:        RTStrCat(pszTmp, cbTmp, " Storage Server Standard Edition"); break;
+        case kRTWinProdType_STORAGE_WORKGROUP_SERVER:       RTStrCat(pszTmp, cbTmp, " Storage Server Workgroup Edition"); break;
+        case kRTWinProdType_ULTIMATE:                       RTStrCat(pszTmp, cbTmp, " Ultimate Edition"); break;
+        case kRTWinProdType_ULTIMATE_N:                     RTStrCat(pszTmp, cbTmp, " Ultimate Edition"); break;
+        case kRTWinProdType_WEB_SERVER:                     RTStrCat(pszTmp, cbTmp, " Web Server Edition (full installation)"); break;
+        case kRTWinProdType_WEB_SERVER_CORE:                RTStrCat(pszTmp, cbTmp, " Web Server Edition (core installation)"); break;
+        case kRTWinProdType_UNDEFINED:                      break;
+    }
+}
+
+
+/**
+ * Services the  RTSYSOSINFO_PRODUCT, RTSYSOSINFO_RELEASE
+ * and RTSYSOSINFO_SERVICE_PACK requests.
+ *
+ * @returns See RTSystemQueryOSInfo.
+ * @param   enmInfo         See RTSystemQueryOSInfo.
+ * @param   pszInfo         See RTSystemQueryOSInfo.
+ * @param   cchInfo         See RTSystemQueryOSInfo.
+ */
+static int rtSystemWinQueryOSVersion(RTSYSOSINFO enmInfo, char *pszInfo, size_t cchInfo)
+{
+    /*
+     * Make sure it's terminated correctly in case of error.
+     */
+    *pszInfo = '\0';
+
+    /*
+     * Check that we got the windows version at init time.
+     */
+    AssertReturn(g_WinOsInfoEx.dwOSVersionInfoSize, VERR_WRONG_ORDER);
+
+    /*
+     * Service the request.
+     */
+    char szTmp[512];
+    szTmp[0] = '\0';
+    switch (enmInfo)
+    {
+        /*
+         * The product name.
+         */
+        case RTSYSOSINFO_PRODUCT:
+        {
+            switch (g_enmWinVer)
+            {
+                case kRTWinOSType_95:           strcpy(szTmp, "Windows 95"); break;
+                case kRTWinOSType_95SP1:        strcpy(szTmp, "Windows 95 (Service Pack 1)"); break;
+                case kRTWinOSType_95OSR2:       strcpy(szTmp, "Windows 95 (OSR 2)"); break;
+                case kRTWinOSType_98:           strcpy(szTmp, "Windows 98"); break;
+                case kRTWinOSType_98SP1:        strcpy(szTmp, "Windows 98 (Service Pack 1)"); break;
+                case kRTWinOSType_98SE:         strcpy(szTmp, "Windows 98 (Second Edition)"); break;
+                case kRTWinOSType_ME:           strcpy(szTmp, "Windows Me"); break;
+                case kRTWinOSType_NT310:        strcpy(szTmp, "Windows NT 3.10"); break;
+                case kRTWinOSType_NT350:        strcpy(szTmp, "Windows NT 3.50"); break;
+                case kRTWinOSType_NT351:        strcpy(szTmp, "Windows NT 3.51"); break;
+                case kRTWinOSType_NT4:          strcpy(szTmp, "Windows NT 4.0"); break;
+                case kRTWinOSType_2K:           strcpy(szTmp, "Windows 2000"); break;
+                case kRTWinOSType_XP:
+                    strcpy(szTmp, "Windows XP");
+                    if (g_WinOsInfoEx.wSuiteMask & VER_SUITE_PERSONAL)
+                        RTStrCat(szTmp, sizeof(szTmp), " Home");
+                    if (    g_WinOsInfoEx.wProductType == VER_NT_WORKSTATION
+                        && !(g_WinOsInfoEx.wSuiteMask & VER_SUITE_PERSONAL))
+                        RTStrCat(szTmp, sizeof(szTmp), " Professional");
+#if 0 /** @todo fixme */
+                    if (GetSystemMetrics(SM_MEDIACENTER))
+                        RTStrCat(szTmp, sizeof(szTmp), " Media Center");
+#endif
+                    break;
+
+                case kRTWinOSType_2003:         strcpy(szTmp, "Windows 2003"); break;
+                case kRTWinOSType_VISTA:
+                {
+                    strcpy(szTmp, "Windows Vista");
+                    rtSystemWinAppendProductType(szTmp, sizeof(szTmp));
+                    break;
+                }
+                case kRTWinOSType_2008:         strcpy(szTmp, "Windows 2008"); break;
+                case kRTWinOSType_7:            strcpy(szTmp, "Windows 7"); break;
+                case kRTWinOSType_2008R2:       strcpy(szTmp, "Windows 2008 R2"); break;
+                case kRTWinOSType_8:            strcpy(szTmp, "Windows 8"); break;
+                case kRTWinOSType_2012:         strcpy(szTmp, "Windows 2012"); break;
+                case kRTWinOSType_81:           strcpy(szTmp, "Windows 8.1"); break;
+                case kRTWinOSType_2012R2:       strcpy(szTmp, "Windows 2012 R2"); break;
+                case kRTWinOSType_10:           strcpy(szTmp, "Windows 10"); break;
+                case kRTWinOSType_2016:         strcpy(szTmp, "Windows 2016"); break;
+                case kRTWinOSType_2019:         strcpy(szTmp, "Windows 2019"); break;
+                case kRTWinOSType_2022:         strcpy(szTmp, "Windows 2022"); break;
+                case kRTWinOSType_11:           strcpy(szTmp, "Windows 11"); break;
+
+                case kRTWinOSType_NT_UNKNOWN:
+                    RTStrPrintf(szTmp, sizeof(szTmp), "Unknown NT v%u.%u",
+                                g_WinOsInfoEx.dwMajorVersion, g_WinOsInfoEx.dwMinorVersion);
+                    break;
+
+                default:
+                    AssertFailed();
+                case kRTWinOSType_UNKNOWN:
+                    RTStrPrintf(szTmp, sizeof(szTmp), "Unknown %d v%u.%u",
+                                g_WinOsInfoEx.dwPlatformId, g_WinOsInfoEx.dwMajorVersion, g_WinOsInfoEx.dwMinorVersion);
+                    break;
+            }
+            break;
+        }
+
+        /*
+         * The release.
+         */
+        case RTSYSOSINFO_RELEASE:
+        {
+            RTStrPrintf(szTmp, sizeof(szTmp), "%u.%u.%u",
+                        g_WinOsInfoEx.dwMajorVersion, g_WinOsInfoEx.dwMinorVersion, g_WinOsInfoEx.dwBuildNumber);
+            break;
+        }
+
+
+        /*
+         * Get the service pack.
+         */
+        case RTSYSOSINFO_SERVICE_PACK:
+        {
+            if (g_WinOsInfoEx.wServicePackMajor)
+            {
+                if (g_WinOsInfoEx.wServicePackMinor)
+                    RTStrPrintf(szTmp, sizeof(szTmp), "%u.%u",
+                                (unsigned)g_WinOsInfoEx.wServicePackMajor, (unsigned)g_WinOsInfoEx.wServicePackMinor);
+                else
+                    RTStrPrintf(szTmp, sizeof(szTmp), "%u",
+                                (unsigned)g_WinOsInfoEx.wServicePackMajor);
+            }
+            else if (g_WinOsInfoEx.szCSDVersion[0])
+            {
+                /* just copy the entire string. */
+                char *pszTmp = szTmp;
+                int rc = RTUtf16ToUtf8Ex(g_WinOsInfoEx.szCSDVersion, RT_ELEMENTS(g_WinOsInfoEx.szCSDVersion),
+                                         &pszTmp, sizeof(szTmp), NULL);
+                if (RT_SUCCESS(rc))
+                    RTStrStripR(szTmp);
+                else
+                    szTmp[0] = '\0';
+                AssertCompile(sizeof(szTmp) > sizeof(g_WinOsInfoEx.szCSDVersion));
+            }
+            else
+            {
+                switch (g_enmWinVer)
+                {
+                    case kRTWinOSType_95SP1:    strcpy(szTmp, "1"); break;
+                    case kRTWinOSType_98SP1:    strcpy(szTmp, "1"); break;
+                    default:
+                        break;
+                }
+            }
+            break;
+        }
+
+        default:
+            AssertFatalFailed();
+    }
+
+    /*
+     * Copy the result to the return buffer.
+     */
+    size_t cchTmp = strlen(szTmp);
+    Assert(cchTmp < sizeof(szTmp));
+    if (cchTmp < cchInfo)
+    {
+        memcpy(pszInfo, szTmp, cchTmp + 1);
+        return VINF_SUCCESS;
+    }
+    memcpy(pszInfo, szTmp, cchInfo - 1);
+    pszInfo[cchInfo - 1] = '\0';
+    return VERR_BUFFER_OVERFLOW;
+}
+
+
+RTDECL(int) RTSystemQueryOSInfo(RTSYSOSINFO enmInfo, char *pszInfo, size_t cchInfo)
+{
+    /*
+     * Quick validation.
+     */
+    AssertReturn(enmInfo > RTSYSOSINFO_INVALID && enmInfo < RTSYSOSINFO_END, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszInfo, VERR_INVALID_POINTER);
+    if (!cchInfo)
+        return VERR_BUFFER_OVERFLOW;
+
+
+    /*
+     * Handle the request.
+     */
+    switch (enmInfo)
+    {
+        case RTSYSOSINFO_PRODUCT:
+        case RTSYSOSINFO_RELEASE:
+        case RTSYSOSINFO_SERVICE_PACK:
+            return rtSystemWinQueryOSVersion(enmInfo, pszInfo, cchInfo);
+
+        case RTSYSOSINFO_VERSION:
+        default:
+            *pszInfo = '\0';
+    }
+
+    return VERR_NOT_SUPPORTED;
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTSystemQueryTotalRam-win.cpp b/src/VBox/Runtime/r3/win/RTSystemQueryTotalRam-win.cpp
new file mode 100644
index 00000000..49465166
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTSystemQueryTotalRam-win.cpp
@@ -0,0 +1,131 @@
+/* $Id: RTSystemQueryTotalRam-win.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryTotalRam, windows ring-3.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/windows.h>
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static bool volatile            g_fInitialized = false;
+typedef BOOL (WINAPI *PFNGLOBALMEMORYSTATUSEX)(LPMEMORYSTATUSEX);
+static PFNGLOBALMEMORYSTATUSEX  g_pfnGlobalMemoryStatusEx = NULL;
+
+
+/**
+ * The GlobalMemoryStatusEx API is not available on older Windows version.
+ *
+ * @returns Pointer to GlobalMemoryStatusEx or NULL if not available.
+ */
+DECLINLINE(PFNGLOBALMEMORYSTATUSEX) rtSystemWinGetExApi(void)
+{
+    PFNGLOBALMEMORYSTATUSEX pfnEx;
+    if (g_fInitialized)
+        pfnEx = g_pfnGlobalMemoryStatusEx;
+    else
+    {
+        pfnEx = (PFNGLOBALMEMORYSTATUSEX)GetProcAddress(g_hModKernel32, "GlobalMemoryStatusEx");
+        g_pfnGlobalMemoryStatusEx = pfnEx;
+        g_fInitialized = true;
+    }
+    return pfnEx;
+}
+
+
+RTDECL(int) RTSystemQueryTotalRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    PFNGLOBALMEMORYSTATUSEX pfnGlobalMemoryStatusEx = rtSystemWinGetExApi();
+    if (pfnGlobalMemoryStatusEx)
+    {
+        MEMORYSTATUSEX MemStatus;
+        MemStatus.dwLength = sizeof(MemStatus);
+        if (pfnGlobalMemoryStatusEx(&MemStatus))
+            *pcb = MemStatus.ullTotalPhys;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        MEMORYSTATUS MemStatus;
+        RT_ZERO(MemStatus);
+        MemStatus.dwLength = sizeof(MemStatus);
+        GlobalMemoryStatus(&MemStatus);
+        *pcb = MemStatus.dwTotalPhys;
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTSystemQueryAvailableRam(uint64_t *pcb)
+{
+    AssertPtrReturn(pcb, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    PFNGLOBALMEMORYSTATUSEX pfnGlobalMemoryStatusEx = rtSystemWinGetExApi();
+    if (pfnGlobalMemoryStatusEx)
+    {
+        MEMORYSTATUSEX MemStatus;
+        MemStatus.dwLength = sizeof(MemStatus);
+        if (pfnGlobalMemoryStatusEx(&MemStatus))
+            *pcb = MemStatus.ullAvailPhys;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        MEMORYSTATUS MemStatus;
+        RT_ZERO(MemStatus);
+        MemStatus.dwLength = sizeof(MemStatus);
+        GlobalMemoryStatus(&MemStatus);
+        *pcb = MemStatus.dwAvailPhys;
+    }
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/win/RTSystemShutdown-win.cpp b/src/VBox/Runtime/r3/win/RTSystemShutdown-win.cpp
new file mode 100644
index 00000000..9a19ef3c
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTSystemShutdown-win.cpp
@@ -0,0 +1,183 @@
+/* $Id: RTSystemShutdown-win.cpp $ */
+/** @file
+ * IPRT - RTSystemShutdown, Windows.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/system.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include <iprt/win/windows.h>
+
+
+RTDECL(int) RTSystemShutdown(RTMSINTERVAL cMsDelay, uint32_t fFlags, const char *pszLogMsg)
+{
+    AssertPtrReturn(pszLogMsg, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTSYSTEM_SHUTDOWN_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Before we start, try grant the necessary privileges.
+     */
+    DWORD  dwErr;
+    HANDLE hToken = NULL;
+    if (OpenThreadToken(GetCurrentThread(), TOKEN_ADJUST_PRIVILEGES, TRUE /*OpenAsSelf*/, &hToken))
+        dwErr = NO_ERROR;
+    else
+    {
+        dwErr  = GetLastError();
+        if (dwErr == ERROR_NO_TOKEN)
+        {
+            if (OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES, &hToken))
+                dwErr = NO_ERROR;
+            else
+                dwErr = GetLastError();
+        }
+    }
+    if (dwErr == NO_ERROR)
+    {
+        union
+        {
+            TOKEN_PRIVILEGES TokenPriv;
+            char ab[sizeof(TOKEN_PRIVILEGES) + sizeof(LUID_AND_ATTRIBUTES)];
+        } u;
+        u.TokenPriv.PrivilegeCount = 1;
+        u.TokenPriv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+        if (LookupPrivilegeValue(NULL /*localhost*/, SE_SHUTDOWN_NAME, &u.TokenPriv.Privileges[0].Luid))
+        {
+            if (!AdjustTokenPrivileges(hToken,
+                                       FALSE /*DisableAllPrivileges*/,
+                                       &u.TokenPriv,
+                                       RT_UOFFSETOF(TOKEN_PRIVILEGES, Privileges[1]),
+                                       NULL,
+                                       NULL) )
+                dwErr = GetLastError();
+        }
+        else
+            dwErr = GetLastError();
+        CloseHandle(hToken);
+    }
+
+    /*
+     * Do some parameter conversion.
+     */
+    PRTUTF16 pwszLogMsg;
+    int rc = RTStrToUtf16(pszLogMsg, &pwszLogMsg);
+    if (RT_FAILURE(rc))
+        return rc;
+    DWORD cSecsTimeout = (cMsDelay + 499) / 1000;
+
+    /*
+     * If we're told to power off the system, we should try use InitiateShutdownW (6.0+)
+     * or ExitWindowsEx (3.50) rather than InitiateSystemShutdownW, because these other
+     * APIs allows us to explicitly specify that we want to power off.
+     *
+     * Note! For NT version 4, 3.51, and 3.50 the system may instaed reboot since the
+     *       x86 HALs typically didn't know how to perform a power off.
+     */
+    bool fDone = false;
+    if (   (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK) == RTSYSTEM_SHUTDOWN_POWER_OFF
+        || (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK) == RTSYSTEM_SHUTDOWN_POWER_OFF_HALT)
+    {
+        /* This API has the grace period thing. */
+        decltype(InitiateShutdownW) *pfnInitiateShutdownW;
+        pfnInitiateShutdownW = (decltype(InitiateShutdownW) *)GetProcAddress(GetModuleHandleW(L"ADVAPI32.DLL"), "InitiateShutdownW");
+        if (pfnInitiateShutdownW)
+        {
+            DWORD fShutdownFlags = SHUTDOWN_POWEROFF;
+            if (fFlags & RTSYSTEM_SHUTDOWN_FORCE)
+                fShutdownFlags |= SHUTDOWN_FORCE_OTHERS | SHUTDOWN_FORCE_SELF;
+            DWORD fReason = SHTDN_REASON_MAJOR_OTHER | (fFlags & RTSYSTEM_SHUTDOWN_PLANNED ? SHTDN_REASON_FLAG_PLANNED : 0);
+            dwErr = pfnInitiateShutdownW(NULL /*pwszMachineName*/, pwszLogMsg, cSecsTimeout, fShutdownFlags, fReason);
+            if (dwErr == ERROR_INVALID_PARAMETER)
+            {
+                fReason &= ~SHTDN_REASON_FLAG_PLANNED; /* just in case... */
+                dwErr = pfnInitiateShutdownW(NULL /*pwszMachineName*/, pwszLogMsg, cSecsTimeout, fShutdownFlags, fReason);
+            }
+            if (dwErr == ERROR_SUCCESS)
+            {
+                rc = VINF_SUCCESS;
+                fDone = true;
+            }
+        }
+
+        if (!fDone)
+        {
+            /* No grace period here, too bad. */
+            decltype(ExitWindowsEx) *pfnExitWindowsEx;
+            pfnExitWindowsEx = (decltype(ExitWindowsEx) *)GetProcAddress(GetModuleHandleW(L"USER32.DLL"), "ExitWindowsEx");
+            if (pfnExitWindowsEx)
+            {
+                DWORD fExitWindows = EWX_POWEROFF | EWX_SHUTDOWN;
+                if (fFlags & RTSYSTEM_SHUTDOWN_FORCE)
+                    fExitWindows |= EWX_FORCE | EWX_FORCEIFHUNG;
+
+                if (pfnExitWindowsEx(fExitWindows, SHTDN_REASON_MAJOR_OTHER))
+                    fDone = true;
+                else if (pfnExitWindowsEx(fExitWindows & ~EWX_FORCEIFHUNG, SHTDN_REASON_MAJOR_OTHER))
+                    fDone = true;
+            }
+        }
+    }
+
+    /*
+     * Fall back on the oldest API.
+     */
+    if (!fDone)
+    {
+        BOOL fRebootAfterShutdown = (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK) == RTSYSTEM_SHUTDOWN_REBOOT
+                                   ? TRUE : FALSE;
+        BOOL fForceAppsClosed     = fFlags & RTSYSTEM_SHUTDOWN_FORCE ? TRUE : FALSE;
+        if (InitiateSystemShutdownW(NULL /*pwszMachineName = NULL = localhost*/,
+                                    pwszLogMsg,
+                                    cSecsTimeout,
+                                    fForceAppsClosed,
+                                    fRebootAfterShutdown))
+            rc = (fFlags & RTSYSTEM_SHUTDOWN_ACTION_MASK) == RTSYSTEM_SHUTDOWN_HALT ? VINF_SYS_MAY_POWER_OFF : VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromWin32(dwErr);
+    }
+
+    RTUtf16Free(pwszLogMsg);
+    return rc;
+}
+RT_EXPORT_SYMBOL(RTSystemShutdown);
+
diff --git a/src/VBox/Runtime/r3/win/RTTimeZoneGetCurrent-win.cpp b/src/VBox/Runtime/r3/win/RTTimeZoneGetCurrent-win.cpp
new file mode 100644
index 00000000..310d8507
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTTimeZoneGetCurrent-win.cpp
@@ -0,0 +1,117 @@
+/* $Id: RTTimeZoneGetCurrent-win.cpp $ */
+/** @file
+ * IPRT - RTTimeZoneGetCurrent, generic.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/errcore.h>
+#include <iprt/env.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+#include <iprt/win/windows.h>
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef DWORD (WINAPI *PFNGETDYNAMICTIMEZONEINFORMATION)(PDYNAMIC_TIME_ZONE_INFORMATION);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Pointer to the GetDynamicTimeZoneInformation API if present. */
+static PFNGETDYNAMICTIMEZONEINFORMATION g_pfnGetDynamicTimeZoneInformation = NULL;
+/** Flipped after we've tried to resolve g_pfnGetDynamicTimeZoneInformation.  */
+static bool volatile                    g_fResolvedApi = false;
+
+
+RTDECL(int) RTTimeZoneGetCurrent(char *pszName, size_t cbName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertReturn(cbName > 0, VERR_BUFFER_OVERFLOW);
+
+    /*
+     * Resolve API.
+     */
+    PFNGETDYNAMICTIMEZONEINFORMATION pfnApi;
+    if (g_fResolvedApi)
+        pfnApi = g_pfnGetDynamicTimeZoneInformation;
+    else
+    {
+        pfnApi = (PFNGETDYNAMICTIMEZONEINFORMATION)GetProcAddress(g_hModKernel32, "GetDynamicTimeZoneInformation");
+        g_pfnGetDynamicTimeZoneInformation = pfnApi;
+        g_fResolvedApi = true;
+    }
+
+    /*
+     * Call the API and convert the name we get.
+     */
+    union
+    {
+        TIME_ZONE_INFORMATION           Tzi;
+        DYNAMIC_TIME_ZONE_INFORMATION   DynTzi;
+    } uBuf;
+    RT_ZERO(uBuf);
+    DWORD     dwRc;
+    PCRTUTF16 pwszSrcName;
+    size_t    cwcSrcName;
+    if (pfnApi)
+    {
+        dwRc = pfnApi(&uBuf.DynTzi);
+        pwszSrcName = uBuf.DynTzi.TimeZoneKeyName;
+        cwcSrcName  = RT_ELEMENTS(uBuf.DynTzi.TimeZoneKeyName);
+    }
+    else
+    {
+        /* Not sure how helpful this fallback really is... */
+        dwRc = GetTimeZoneInformation(&uBuf.Tzi);
+        pwszSrcName = uBuf.Tzi.StandardName;
+        cwcSrcName  = RT_ELEMENTS(uBuf.Tzi.StandardName);
+    }
+    if (dwRc != TIME_ZONE_ID_INVALID)
+    {
+        Assert(*pwszSrcName != '\0');
+        return RTUtf16ToUtf8Ex(pwszSrcName, cwcSrcName, &pszName, cbName, &cbName);
+    }
+    return RTErrConvertFromWin32(GetLastError());
+}
+
diff --git a/src/VBox/Runtime/r3/win/RTUuidCreate-win.cpp b/src/VBox/Runtime/r3/win/RTUuidCreate-win.cpp
new file mode 100644
index 00000000..99a5692f
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/RTUuidCreate-win.cpp
@@ -0,0 +1,82 @@
+/* $Id: RTUuidCreate-win.cpp $ */
+/** @file
+ * IPRT - UUID, Windows RTUuidCreate implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_UUID
+#include <iprt/win/windows.h>
+
+#include <iprt/uuid.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/rand.h>
+
+#include "internal-r3-win.h"
+
+
+RTDECL(int)  RTUuidCreate(PRTUUID pUuid)
+{
+    /*
+     * Input validation.
+     */
+    AssertPtrReturn(pUuid, VERR_INVALID_POINTER);
+
+    /*
+     * When using the UuidCreate API shortly after boot on NT 3.1 it typcially
+     * hangs for a long long time while polling for some service to start.
+     * What then usually happens next is a failure because it couldn't figure
+     * out the MAC address of the NIC.  So, on NT 3.1 we always use the fallback.
+     */
+    if (g_enmWinVer != kRTWinOSType_NT310)
+    {
+        RPC_STATUS rc = UuidCreate((UUID *)pUuid);
+        if (   rc == RPC_S_OK
+            || rc == RPC_S_UUID_LOCAL_ONLY)
+            return VINF_SUCCESS;
+        AssertMsg(rc == RPC_S_UUID_NO_ADDRESS, ("UuidCreate -> %u (%#x)\n", rc, rc));
+    }
+
+    /*
+     * Use generic implementation as fallback (copy of RTUuidCreate-generic.cpp).
+     */
+    RTRandBytes(pUuid, sizeof(*pUuid));
+    pUuid->Gen.u8ClockSeqHiAndReserved = (pUuid->Gen.u8ClockSeqHiAndReserved & 0x3f) | 0x80;
+    pUuid->Gen.u16TimeHiAndVersion     = (pUuid->Gen.u16TimeHiAndVersion & 0x0fff) | 0x4000;
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-msvcp100-win32.def b/src/VBox/Runtime/r3/win/VBoxRT-msvcp100-win32.def
new file mode 100644
index 00000000..5395dc50
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-msvcp100-win32.def
@@ -0,0 +1,1678 @@
+
+  ??0?$_Yarn@D@std@@QAE@ABV01@@Z
+  ??0?$_Yarn@D@std@@QAE@PBD@Z
+  ??0?$_Yarn@D@std@@QAE@XZ
+  ??0?$basic_ios@DU?$char_traits@D@std@@@std@@IAE@XZ
+  ??0?$basic_ios@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@@Z
+  ??0?$basic_ios@GU?$char_traits@G@std@@@std@@IAE@XZ
+  ??0?$basic_ios@GU?$char_traits@G@std@@@std@@QAE@PAV?$basic_streambuf@GU?$char_traits@G@std@@@1@@Z
+  ??0?$basic_ios@_WU?$char_traits@_W@std@@@std@@IAE@XZ
+  ??0?$basic_ios@_WU?$char_traits@_W@std@@@std@@QAE@PAV?$basic_streambuf@_WU?$char_traits@_W@std@@@1@@Z
+  ??0?$basic_iostream@DU?$char_traits@D@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_iostream@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@@Z
+  ??0?$basic_iostream@GU?$char_traits@G@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_iostream@GU?$char_traits@G@std@@@std@@QAE@PAV?$basic_streambuf@GU?$char_traits@G@std@@@1@@Z
+  ??0?$basic_iostream@_WU?$char_traits@_W@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_iostream@_WU?$char_traits@_W@std@@@std@@QAE@PAV?$basic_streambuf@_WU?$char_traits@_W@std@@@1@@Z
+  ??0?$basic_istream@DU?$char_traits@D@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_istream@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@_N1@Z
+  ??0?$basic_istream@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@_N@Z
+  ??0?$basic_istream@DU?$char_traits@D@std@@@std@@QAE@W4_Uninitialized@1@@Z
+  ??0?$basic_istream@GU?$char_traits@G@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_istream@GU?$char_traits@G@std@@@std@@QAE@PAV?$basic_streambuf@GU?$char_traits@G@std@@@1@_N1@Z
+  ??0?$basic_istream@GU?$char_traits@G@std@@@std@@QAE@PAV?$basic_streambuf@GU?$char_traits@G@std@@@1@_N@Z
+  ??0?$basic_istream@GU?$char_traits@G@std@@@std@@QAE@W4_Uninitialized@1@@Z
+  ??0?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAE@PAV?$basic_streambuf@_WU?$char_traits@_W@std@@@1@_N1@Z
+  ??0?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAE@PAV?$basic_streambuf@_WU?$char_traits@_W@std@@@1@_N@Z
+  ??0?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAE@W4_Uninitialized@1@@Z
+  ??0?$basic_ostream@DU?$char_traits@D@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_ostream@DU?$char_traits@D@std@@@std@@QAE@PAV?$basic_streambuf@DU?$char_traits@D@std@@@1@_N@Z
+  ??0?$basic_ostream@DU?$char_traits@D@std@@@std@@QAE@W4_Uninitialized@1@_N@Z
+  ??0?$basic_ostream@GU?$char_traits@G@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_ostream@GU?$char_traits@G@std@@@std@@QAE@PAV?$basic_streambuf@GU?$char_traits@G@std@@@1@_N@Z
+  ??0?$basic_ostream@GU?$char_traits@G@std@@@std@@QAE@W4_Uninitialized@1@_N@Z
+  ??0?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAE@$$QAV01@@Z
+  ??0?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAE@PAV?$basic_streambuf@_WU?$char_traits@_W@std@@@1@_N@Z
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+  ?do_scan_is@?$ctype@G@std@@MBEPBGFPBG0@Z
+  ?do_scan_is@?$ctype@_W@std@@MBEPB_WFPB_W0@Z
+  ?do_scan_not@?$ctype@G@std@@MBEPBGFPBG0@Z
+  ?do_scan_not@?$ctype@_W@std@@MBEPB_WFPB_W0@Z
+  ?do_tolower@?$ctype@D@std@@MBEDD@Z
+  ?do_tolower@?$ctype@D@std@@MBEPBDPADPBD@Z
+  ?do_tolower@?$ctype@G@std@@MBEGG@Z
+  ?do_tolower@?$ctype@G@std@@MBEPBGPAGPBG@Z
+  ?do_tolower@?$ctype@_W@std@@MBEPB_WPA_WPB_W@Z
+  ?do_tolower@?$ctype@_W@std@@MBE_W_W@Z
+  ?do_toupper@?$ctype@D@std@@MBEDD@Z
+  ?do_toupper@?$ctype@D@std@@MBEPBDPADPBD@Z
+  ?do_toupper@?$ctype@G@std@@MBEGG@Z
+  ?do_toupper@?$ctype@G@std@@MBEPBGPAGPBG@Z
+  ?do_toupper@?$ctype@_W@std@@MBEPB_WPA_WPB_W@Z
+  ?do_toupper@?$ctype@_W@std@@MBE_W_W@Z
+  ?do_unshift@?$codecvt@DDH@std@@MBEHAAHPAD1AAPAD@Z
+  ?do_unshift@?$codecvt@GDH@std@@MBEHAAHPAD1AAPAD@Z
+  ?do_unshift@?$codecvt@_WDH@std@@MBEHAAHPAD1AAPAD@Z
+  ?do_widen@?$ctype@D@std@@MBEDD@Z
+  ?do_widen@?$ctype@D@std@@MBEPBDPBD0PAD@Z
+  ?do_widen@?$ctype@G@std@@MBEGD@Z
+  ?do_widen@?$ctype@G@std@@MBEPBDPBD0PAG@Z
+  ?do_widen@?$ctype@_W@std@@MBEPBDPBD0PA_W@Z
+  ?do_widen@?$ctype@_W@std@@MBE_WD@Z
+  ?done@agent@Concurrency@@IAE_NXZ
+  ?eback@?$basic_streambuf@DU?$char_traits@D@std@@@std@@IBEPADXZ
+  ?eback@?$basic_streambuf@GU?$char_traits@G@std@@@std@@IBEPAGXZ
+  ?eback@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@IBEPA_WXZ
+  ?egptr@?$basic_streambuf@DU?$char_traits@D@std@@@std@@IBEPADXZ
+  ?egptr@?$basic_streambuf@GU?$char_traits@G@std@@@std@@IBEPAGXZ
+  ?egptr@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@IBEPA_WXZ
+  ?empty@?$_Yarn@D@std@@QBE_NXZ
+  ?empty@locale@std@@SA?AV12@XZ
+  ?encoding@codecvt_base@std@@QBEHXZ
+  ?endl@std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@1@AAV21@@Z
+  ?endl@std@@YAAAV?$basic_ostream@GU?$char_traits@G@std@@@1@AAV21@@Z
+  ?endl@std@@YAAAV?$basic_ostream@_WU?$char_traits@_W@std@@@1@AAV21@@Z
+  ?ends@std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@1@AAV21@@Z
+  ?ends@std@@YAAAV?$basic_ostream@GU?$char_traits@G@std@@@1@AAV21@@Z
+  ?ends@std@@YAAAV?$basic_ostream@_WU?$char_traits@_W@std@@@1@AAV21@@Z
+  ?eof@ios_base@std@@QBE_NXZ
+  ?epptr@?$basic_streambuf@DU?$char_traits@D@std@@@std@@IBEPADXZ
+  ?epptr@?$basic_streambuf@GU?$char_traits@G@std@@@std@@IBEPAGXZ
+  ?epptr@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@IBEPA_WXZ
+  ?epsilon@?$numeric_limits@C@std@@SACXZ
+  ?epsilon@?$numeric_limits@D@std@@SADXZ
+  ?epsilon@?$numeric_limits@E@std@@SAEXZ
+  ?epsilon@?$numeric_limits@F@std@@SAFXZ
+  ?epsilon@?$numeric_limits@G@std@@SAGXZ
+  ?epsilon@?$numeric_limits@H@std@@SAHXZ
+  ?epsilon@?$numeric_limits@I@std@@SAIXZ
+  ?epsilon@?$numeric_limits@J@std@@SAJXZ
+  ?epsilon@?$numeric_limits@K@std@@SAKXZ
+  ?epsilon@?$numeric_limits@M@std@@SAMXZ
+  ?epsilon@?$numeric_limits@N@std@@SANXZ
+  ?epsilon@?$numeric_limits@O@std@@SAOXZ
+  ?epsilon@?$numeric_limits@_J@std@@SA_JXZ
+  ?epsilon@?$numeric_limits@_K@std@@SA_KXZ
+  ?epsilon@?$numeric_limits@_N@std@@SA_NXZ
+  ?epsilon@?$numeric_limits@_W@std@@SA_WXZ
+  ?exceptions@ios_base@std@@QAEXH@Z
+  ?exceptions@ios_base@std@@QAEXI@Z
+  ?exceptions@ios_base@std@@QBEHXZ
+  ?fail@ios_base@std@@QBE_NXZ
+  ?fill@?$basic_ios@DU?$char_traits@D@std@@@std@@QAEDD@Z
+  ?fill@?$basic_ios@DU?$char_traits@D@std@@@std@@QBEDXZ
+  ?fill@?$basic_ios@GU?$char_traits@G@std@@@std@@QAEGG@Z
+  ?fill@?$basic_ios@GU?$char_traits@G@std@@@std@@QBEGXZ
+  ?fill@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QAE_W_W@Z
+  ?fill@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QBE_WXZ
+  ?flags@ios_base@std@@QAEHH@Z
+  ?flags@ios_base@std@@QBEHXZ
+  ?flush@?$basic_ostream@DU?$char_traits@D@std@@@std@@QAEAAV12@XZ
+  ?flush@?$basic_ostream@GU?$char_traits@G@std@@@std@@QAEAAV12@XZ
+  ?flush@?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@XZ
+  ?flush@std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@1@AAV21@@Z
+  ?flush@std@@YAAAV?$basic_ostream@GU?$char_traits@G@std@@@1@AAV21@@Z
+  ?flush@std@@YAAAV?$basic_ostream@_WU?$char_traits@_W@std@@@1@AAV21@@Z
+  ?gbump@?$basic_streambuf@DU?$char_traits@D@std@@@std@@IAEXH@Z
+  ?gbump@?$basic_streambuf@GU?$char_traits@G@std@@@std@@IAEXH@Z
+  ?gbump@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@IAEXH@Z
+  ?gcount@?$basic_istream@DU?$char_traits@D@std@@@std@@QBE_JXZ
+  ?gcount@?$basic_istream@GU?$char_traits@G@std@@@std@@QBE_JXZ
+  ?gcount@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QBE_JXZ
+  ?generic_category@std@@YAABVerror_category@1@XZ
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@AAD@Z
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@AAV?$basic_streambuf@DU?$char_traits@D@std@@@2@@Z
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@AAV?$basic_streambuf@DU?$char_traits@D@std@@@2@D@Z
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@PAD_J@Z
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@PAD_JD@Z
+  ?get@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEHXZ
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@AAG@Z
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@AAV?$basic_streambuf@GU?$char_traits@G@std@@@2@@Z
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@AAV?$basic_streambuf@GU?$char_traits@G@std@@@2@G@Z
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@PAG_J@Z
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@PAG_JG@Z
+  ?get@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEGXZ
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@AAV?$basic_streambuf@_WU?$char_traits@_W@std@@@2@@Z
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@AAV?$basic_streambuf@_WU?$char_traits@_W@std@@@2@_W@Z
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@AA_W@Z
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@PA_W_J@Z
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@PA_W_J_W@Z
+  ?get@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEGXZ
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAG@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAI@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAJ@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAK@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAM@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAN@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAO@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAAPAX@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAA_J@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAA_K@Z
+  ?get@?$num_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHAA_N@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAG@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAI@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAJ@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAK@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAM@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAN@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAO@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAAPAX@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAA_J@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAA_K@Z
+  ?get@?$num_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHAA_N@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAG@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAI@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAJ@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAK@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAM@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAN@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAO@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAAPAX@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAA_J@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAA_K@Z
+  ?get@?$num_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHAA_N@Z
+  ?get@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@DD@Z
+  ?get@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@PBD4@Z
+  ?get@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@DD@Z
+  ?get@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@PBG4@Z
+  ?get@?$time_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@DD@Z
+  ?get@?$time_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@PB_W4@Z
+  ?get_date@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_date@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_date@?$time_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_monthname@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_monthname@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_monthname@?$time_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_time@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_time@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_time@?$time_get@_WV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@_WU?$char_traits@_W@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_weekday@?$time_get@DV?$istreambuf_iterator@DU?$char_traits@D@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@DU?$char_traits@D@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
+  ?get_weekday@?$time_get@GV?$istreambuf_iterator@GU?$char_traits@G@std@@@std@@@std@@QBE?AV?$istreambuf_iterator@GU?$char_traits@G@std@@@2@V32@0AAVios_base@2@AAHPAUtm@@@Z
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+  ?signaling_NaN@?$numeric_limits@G@std@@SAGXZ
+  ?signaling_NaN@?$numeric_limits@H@std@@SAHXZ
+  ?signaling_NaN@?$numeric_limits@I@std@@SAIXZ
+  ?signaling_NaN@?$numeric_limits@J@std@@SAJXZ
+  ?signaling_NaN@?$numeric_limits@K@std@@SAKXZ
+  ?signaling_NaN@?$numeric_limits@M@std@@SAMXZ
+  ?signaling_NaN@?$numeric_limits@N@std@@SANXZ
+  ?signaling_NaN@?$numeric_limits@O@std@@SAOXZ
+  ?signaling_NaN@?$numeric_limits@_J@std@@SA_JXZ
+  ?signaling_NaN@?$numeric_limits@_K@std@@SA_KXZ
+  ?signaling_NaN@?$numeric_limits@_N@std@@SA_NXZ
+  ?signaling_NaN@?$numeric_limits@_W@std@@SA_WXZ
+  ?snextc@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAEHXZ
+  ?snextc@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAEGXZ
+  ?snextc@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAEGXZ
+  ?sputbackc@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAEHD@Z
+  ?sputbackc@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAEGG@Z
+  ?sputbackc@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAEG_W@Z
+  ?sputc@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAEHD@Z
+  ?sputc@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAEGG@Z
+  ?sputc@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAEG_W@Z
+  ?sputn@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAE_JPBD_J@Z
+  ?sputn@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAE_JPBG_J@Z
+  ?sputn@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAE_JPB_W_J@Z
+  ?start@agent@Concurrency@@QAE_NXZ
+  ?status@agent@Concurrency@@QAE?AW4agent_status@2@XZ
+  ?status_port@agent@Concurrency@@QAEPAV?$ISource@W4agent_status@Concurrency@@@2@XZ
+  ?stossc@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAEXXZ
+  ?stossc@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAEXXZ
+  ?stossc@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAEXXZ
+  ?sungetc@?$basic_streambuf@DU?$char_traits@D@std@@@std@@QAEHXZ
+  ?sungetc@?$basic_streambuf@GU?$char_traits@G@std@@@std@@QAEGXZ
+  ?sungetc@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@QAEGXZ
+  ?swap@?$basic_ios@DU?$char_traits@D@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_ios@GU?$char_traits@G@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_iostream@DU?$char_traits@D@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_iostream@GU?$char_traits@G@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_iostream@_WU?$char_traits@_W@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_ostream@DU?$char_traits@D@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_ostream@GU?$char_traits@G@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAEXAAV12@@Z
+  ?swap@?$basic_streambuf@DU?$char_traits@D@std@@@std@@IAEXAAV12@@Z
+  ?swap@?$basic_streambuf@GU?$char_traits@G@std@@@std@@IAEXAAV12@@Z
+  ?swap@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@IAEXAAV12@@Z
+  ?swap@ios_base@std@@QAEXAAV12@@Z
+  ?sync@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEHXZ
+  ?sync@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEHXZ
+  ?sync@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEHXZ
+  ?sync@?$basic_streambuf@DU?$char_traits@D@std@@@std@@MAEHXZ
+  ?sync@?$basic_streambuf@GU?$char_traits@G@std@@@std@@MAEHXZ
+  ?sync@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@MAEHXZ
+  ?sync_with_stdio@ios_base@std@@SA_N_N@Z
+  ?system_category@std@@YAABVerror_category@1@XZ
+  ?table@?$ctype@D@std@@QBEPBFXZ
+  ?table_size@?$ctype@D@std@@2IB
+  ?tellg@?$basic_istream@DU?$char_traits@D@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tellg@?$basic_istream@GU?$char_traits@G@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tellg@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tellp@?$basic_ostream@DU?$char_traits@D@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tellp@?$basic_ostream@GU?$char_traits@G@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tellp@?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAE?AV?$fpos@H@2@XZ
+  ?tie@?$basic_ios@DU?$char_traits@D@std@@@std@@QAEPAV?$basic_ostream@DU?$char_traits@D@std@@@2@PAV32@@Z
+  ?tie@?$basic_ios@DU?$char_traits@D@std@@@std@@QBEPAV?$basic_ostream@DU?$char_traits@D@std@@@2@XZ
+  ?tie@?$basic_ios@GU?$char_traits@G@std@@@std@@QAEPAV?$basic_ostream@GU?$char_traits@G@std@@@2@PAV32@@Z
+  ?tie@?$basic_ios@GU?$char_traits@G@std@@@std@@QBEPAV?$basic_ostream@GU?$char_traits@G@std@@@2@XZ
+  ?tie@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QAEPAV?$basic_ostream@_WU?$char_traits@_W@std@@@2@PAV32@@Z
+  ?tie@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QBEPAV?$basic_ostream@_WU?$char_traits@_W@std@@@2@XZ
+  ?tinyness_before@_Num_base@std@@2_NB
+  ?tinyness_before@_Num_float_base@std@@2_NB
+  ?tolower@?$ctype@D@std@@QBEDD@Z
+  ?tolower@?$ctype@D@std@@QBEPBDPADPBD@Z
+  ?tolower@?$ctype@G@std@@QBEGG@Z
+  ?tolower@?$ctype@G@std@@QBEPBGPAGPBG@Z
+  ?tolower@?$ctype@_W@std@@QBEPB_WPA_WPB_W@Z
+  ?tolower@?$ctype@_W@std@@QBE_W_W@Z
+  ?toupper@?$ctype@D@std@@QBEDD@Z
+  ?toupper@?$ctype@D@std@@QBEPBDPADPBD@Z
+  ?toupper@?$ctype@G@std@@QBEGG@Z
+  ?toupper@?$ctype@G@std@@QBEPBGPAGPBG@Z
+  ?toupper@?$ctype@_W@std@@QBEPB_WPA_WPB_W@Z
+  ?toupper@?$ctype@_W@std@@QBE_W_W@Z
+  ?traps@_Num_base@std@@2_NB
+  ?traps@_Num_float_base@std@@2_NB
+  ?uflow@?$basic_streambuf@DU?$char_traits@D@std@@@std@@MAEHXZ
+  ?uflow@?$basic_streambuf@GU?$char_traits@G@std@@@std@@MAEGXZ
+  ?uflow@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@MAEGXZ
+  ?uncaught_exception@std@@YA_NXZ
+  ?underflow@?$basic_streambuf@DU?$char_traits@D@std@@@std@@MAEHXZ
+  ?underflow@?$basic_streambuf@GU?$char_traits@G@std@@@std@@MAEGXZ
+  ?underflow@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@MAEGXZ
+  ?unget@?$basic_istream@DU?$char_traits@D@std@@@std@@QAEAAV12@XZ
+  ?unget@?$basic_istream@GU?$char_traits@G@std@@@std@@QAEAAV12@XZ
+  ?unget@?$basic_istream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@XZ
+  ?unsetf@ios_base@std@@QAEXH@Z
+  ?unshift@?$codecvt@DDH@std@@QBEHAAHPAD1AAPAD@Z
+  ?unshift@?$codecvt@GDH@std@@QBEHAAHPAD1AAPAD@Z
+  ?unshift@?$codecvt@_WDH@std@@QBEHAAHPAD1AAPAD@Z
+  ?wait@agent@Concurrency@@SA?AW4agent_status@2@PAV12@I@Z
+  ?wait_for_all@agent@Concurrency@@SAXIPAPAV12@PAW4agent_status@2@I@Z
+  ?wait_for_one@agent@Concurrency@@SAXIPAPAV12@AAW4agent_status@2@AAII@Z
+  ?wcerr@std@@3V?$basic_ostream@GU?$char_traits@G@std@@@1@A
+  ?wcerr@std@@3V?$basic_ostream@_WU?$char_traits@_W@std@@@1@A
+  ?wcin@std@@3V?$basic_istream@GU?$char_traits@G@std@@@1@A
+  ?wcin@std@@3V?$basic_istream@_WU?$char_traits@_W@std@@@1@A
+  ?wclog@std@@3V?$basic_ostream@GU?$char_traits@G@std@@@1@A
+  ?wclog@std@@3V?$basic_ostream@_WU?$char_traits@_W@std@@@1@A
+  ?wcout@std@@3V?$basic_ostream@GU?$char_traits@G@std@@@1@A
+  ?wcout@std@@3V?$basic_ostream@_WU?$char_traits@_W@std@@@1@A
+  ?widen@?$basic_ios@DU?$char_traits@D@std@@@std@@QBEDD@Z
+  ?widen@?$basic_ios@GU?$char_traits@G@std@@@std@@QBEGD@Z
+  ?widen@?$basic_ios@_WU?$char_traits@_W@std@@@std@@QBE_WD@Z
+  ?widen@?$ctype@D@std@@QBEDD@Z
+  ?widen@?$ctype@D@std@@QBEPBDPBD0PAD@Z
+  ?widen@?$ctype@G@std@@QBEGD@Z
+  ?widen@?$ctype@G@std@@QBEPBDPBD0PAG@Z
+  ?widen@?$ctype@_W@std@@QBEPBDPBD0PA_W@Z
+  ?widen@?$ctype@_W@std@@QBE_WD@Z
+  ?width@ios_base@std@@QAE_J_J@Z
+  ?width@ios_base@std@@QBE_JXZ
+  ?write@?$basic_ostream@DU?$char_traits@D@std@@@std@@QAEAAV12@PBD_J@Z
+  ?write@?$basic_ostream@GU?$char_traits@G@std@@@std@@QAEAAV12@PBG_J@Z
+  ?write@?$basic_ostream@_WU?$char_traits@_W@std@@@std@@QAEAAV12@PB_W_J@Z
+  ?ws@std@@YAAAV?$basic_istream@DU?$char_traits@D@std@@@1@AAV21@@Z
+  ?ws@std@@YAAAV?$basic_istream@GU?$char_traits@G@std@@@1@AAV21@@Z
+  ?ws@std@@YAAAV?$basic_istream@_WU?$char_traits@_W@std@@@1@AAV21@@Z
+  ?xalloc@ios_base@std@@SAHXZ
+  ?xsgetn@?$basic_streambuf@DU?$char_traits@D@std@@@std@@MAE_JPAD_J@Z
+  ?xsgetn@?$basic_streambuf@GU?$char_traits@G@std@@@std@@MAE_JPAG_J@Z
+  ?xsgetn@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@MAE_JPA_W_J@Z
+  ?xsputn@?$basic_streambuf@DU?$char_traits@D@std@@@std@@MAE_JPBD_J@Z
+  ?xsputn@?$basic_streambuf@GU?$char_traits@G@std@@@std@@MAE_JPBG_J@Z
+  ?xsputn@?$basic_streambuf@_WU?$char_traits@_W@std@@@std@@MAE_JPB_W_J@Z
+  _Cosh
+  _Denorm
+  _Dnorm
+  _Dscale
+  _Dtest
+  _Eps
+  _Exp
+  _FCosh
+  _FDenorm
+  _FDnorm
+  _FDscale
+  _FDtest
+  _FEps
+  _FExp
+  _FInf
+  _FNan
+  _FRteps
+  _FSinh
+  _FSnan
+  _FXbig
+  _GetLocaleForCP
+  _Getcoll
+  _Getctype
+  _Getcvt
+  _Getdateorder
+  _Getwctype
+  _Getwctypes
+  _Hugeval
+  _Inf
+  _LCosh
+  _LDenorm
+  _LDscale
+  _LDtest
+  _LEps
+  _LExp
+  _LInf
+  _LNan
+  _LPoly
+  _LRteps
+  _LSinh
+  _LSnan
+  _LXbig
+  _LZero
+  _Mbrtowc
+  _Mtxdst
+  _Mtxinit
+  _Mtxlock
+  _Mtxunlock
+  _Nan
+  _Once
+  _Poly
+  _Rteps
+  _Sinh
+  _Snan
+  _Stod
+  _Stodx
+  _Stof
+  _Stofx
+  _Stold
+  _Stoldx
+  _Stoll
+  _Stollx
+  _Stolx
+  _Stoul
+  _Stoull
+  _Stoullx
+  _Stoulx
+  _Strcoll
+  _Strxfrm
+  _Tolower
+  _Toupper
+  _Towlower
+  _Towupper
+  _Wcrtomb
+  _Wcscoll
+  _Wcsxfrm
+  _Xbig
+  __Wcrtomb_lk
+  towctrans
+  wctrans
+  wctype
+
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-msvcr100-win32.def b/src/VBox/Runtime/r3/win/VBoxRT-msvcr100-win32.def
new file mode 100644
index 00000000..6317e658
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-msvcr100-win32.def
@@ -0,0 +1,1640 @@
+
+  ;
+  _except_handler4
+  ;_heap_init
+  ;__crtExitProcess
+  ;_NMSG_WRITE
+  ;_FF_MSGBANNER
+  ;_cinit
+  ;_setenvp
+  ;__crtGetEnvironmentStringsA
+  ;_ioinit
+  ;_mtinit
+
+  _initterm=my_initterm
+  __dllonexit=my_dllonexit
+  __getmainargs=my_getmainargs
+  __setusermatherr=my_setusermatherr
+
+  _onexit DATA ; the one is crazy. atonexit.obj in msvcrt.lib which calls the __imp___onexit directly.
+
+  ; MSVCR100.DLL exports
+  ??0?$_SpinWait@$0A@@details@Concurrency@@QAE@P6AXXZ@Z
+  ??0SchedulerPolicy@Concurrency@@QAA@IZZ
+  ??0SchedulerPolicy@Concurrency@@QAE@ABV01@@Z
+  ??0SchedulerPolicy@Concurrency@@QAE@XZ
+  ??0_NonReentrantBlockingLock@details@Concurrency@@QAE@XZ
+  ??0_NonReentrantPPLLock@details@Concurrency@@QAE@XZ
+  ??0_ReaderWriterLock@details@Concurrency@@QAE@XZ
+  ??0_ReentrantBlockingLock@details@Concurrency@@QAE@XZ
+  ??0_ReentrantLock@details@Concurrency@@QAE@XZ
+  ??0_ReentrantPPLLock@details@Concurrency@@QAE@XZ
+  ??0_Scoped_lock@_NonReentrantPPLLock@details@Concurrency@@QAE@AAV123@@Z
+  ??0_Scoped_lock@_ReentrantPPLLock@details@Concurrency@@QAE@AAV123@@Z
+  ??0_SpinLock@details@Concurrency@@QAE@ACJ@Z
+  ??0_TaskCollection@details@Concurrency@@QAE@XZ
+  ??0_Timer@details@Concurrency@@IAE@I_N@Z
+  ??0__non_rtti_object@std@@QAE@ABV01@@Z
+  ??0__non_rtti_object@std@@QAE@PBD@Z
+  ;fixme-not-in-libcmt.lib; ??0bad_cast@std@@AAE@PBQBD@Z
+  ??0bad_cast@std@@QAE@ABV01@@Z
+  ??0bad_cast@std@@QAE@PBD@Z
+  ??0bad_target@Concurrency@@QAE@PBD@Z
+  ??0bad_target@Concurrency@@QAE@XZ
+  ??0bad_typeid@std@@QAE@ABV01@@Z
+  ??0bad_typeid@std@@QAE@PBD@Z
+  ??0context_self_unblock@Concurrency@@QAE@PBD@Z
+  ??0context_self_unblock@Concurrency@@QAE@XZ
+  ??0context_unblock_unbalanced@Concurrency@@QAE@PBD@Z
+  ??0context_unblock_unbalanced@Concurrency@@QAE@XZ
+  ??0critical_section@Concurrency@@QAE@XZ
+  ??0default_scheduler_exists@Concurrency@@QAE@PBD@Z
+  ??0default_scheduler_exists@Concurrency@@QAE@XZ
+  ??0event@Concurrency@@QAE@XZ
+  ??0exception@std@@QAE@ABQBD@Z
+  ??0exception@std@@QAE@ABQBDH@Z
+  ??0exception@std@@QAE@ABV01@@Z
+  ??0exception@std@@QAE@XZ
+  ??0improper_lock@Concurrency@@QAE@PBD@Z
+  ??0improper_lock@Concurrency@@QAE@XZ
+  ??0improper_scheduler_attach@Concurrency@@QAE@PBD@Z
+  ??0improper_scheduler_attach@Concurrency@@QAE@XZ
+  ??0improper_scheduler_detach@Concurrency@@QAE@PBD@Z
+  ??0improper_scheduler_detach@Concurrency@@QAE@XZ
+  ??0improper_scheduler_reference@Concurrency@@QAE@PBD@Z
+  ??0improper_scheduler_reference@Concurrency@@QAE@XZ
+  ??0invalid_link_target@Concurrency@@QAE@PBD@Z
+  ??0invalid_link_target@Concurrency@@QAE@XZ
+  ??0invalid_multiple_scheduling@Concurrency@@QAE@PBD@Z
+  ??0invalid_multiple_scheduling@Concurrency@@QAE@XZ
+  ??0invalid_operation@Concurrency@@QAE@PBD@Z
+  ??0invalid_operation@Concurrency@@QAE@XZ
+  ??0invalid_oversubscribe_operation@Concurrency@@QAE@PBD@Z
+  ??0invalid_oversubscribe_operation@Concurrency@@QAE@XZ
+  ??0invalid_scheduler_policy_key@Concurrency@@QAE@PBD@Z
+  ??0invalid_scheduler_policy_key@Concurrency@@QAE@XZ
+  ??0invalid_scheduler_policy_thread_specification@Concurrency@@QAE@PBD@Z
+  ??0invalid_scheduler_policy_thread_specification@Concurrency@@QAE@XZ
+  ??0invalid_scheduler_policy_value@Concurrency@@QAE@PBD@Z
+  ??0invalid_scheduler_policy_value@Concurrency@@QAE@XZ
+  ??0message_not_found@Concurrency@@QAE@PBD@Z
+  ??0message_not_found@Concurrency@@QAE@XZ
+  ??0missing_wait@Concurrency@@QAE@PBD@Z
+  ??0missing_wait@Concurrency@@QAE@XZ
+  ??0nested_scheduler_missing_detach@Concurrency@@QAE@PBD@Z
+  ??0nested_scheduler_missing_detach@Concurrency@@QAE@XZ
+  ??0operation_timed_out@Concurrency@@QAE@PBD@Z
+  ??0operation_timed_out@Concurrency@@QAE@XZ
+  ??0reader_writer_lock@Concurrency@@QAE@XZ
+  ??0scheduler_not_attached@Concurrency@@QAE@PBD@Z
+  ??0scheduler_not_attached@Concurrency@@QAE@XZ
+  ??0scheduler_resource_allocation_error@Concurrency@@QAE@J@Z
+  ??0scheduler_resource_allocation_error@Concurrency@@QAE@PBDJ@Z
+  ??0scoped_lock@critical_section@Concurrency@@QAE@AAV12@@Z
+  ??0scoped_lock@reader_writer_lock@Concurrency@@QAE@AAV12@@Z
+  ??0scoped_lock_read@reader_writer_lock@Concurrency@@QAE@AAV12@@Z
+  ??0task_canceled@details@Concurrency@@QAE@PBD@Z
+  ??0task_canceled@details@Concurrency@@QAE@XZ
+  ??0unsupported_os@Concurrency@@QAE@PBD@Z
+  ??0unsupported_os@Concurrency@@QAE@XZ
+  ??1SchedulerPolicy@Concurrency@@QAE@XZ
+  ??1_NonReentrantBlockingLock@details@Concurrency@@QAE@XZ
+  ??1_ReentrantBlockingLock@details@Concurrency@@QAE@XZ
+  ??1_Scoped_lock@_NonReentrantPPLLock@details@Concurrency@@QAE@XZ
+  ??1_Scoped_lock@_ReentrantPPLLock@details@Concurrency@@QAE@XZ
+  ??1_SpinLock@details@Concurrency@@QAE@XZ
+  ??1_TaskCollection@details@Concurrency@@QAE@XZ
+  ??1_Timer@details@Concurrency@@IAE@XZ
+  ??1__non_rtti_object@std@@UAE@XZ
+  ??1bad_cast@std@@UAE@XZ
+  ??1bad_typeid@std@@UAE@XZ
+  ??1critical_section@Concurrency@@QAE@XZ
+  ??1event@Concurrency@@QAE@XZ
+  ??1exception@std@@UAE@XZ
+  ??1reader_writer_lock@Concurrency@@QAE@XZ
+  ??1scoped_lock@critical_section@Concurrency@@QAE@XZ
+  ??1scoped_lock@reader_writer_lock@Concurrency@@QAE@XZ
+  ??1scoped_lock_read@reader_writer_lock@Concurrency@@QAE@XZ
+  ??1type_info@@UAE@XZ
+  ??2@YAPAXI@Z
+  ??2@YAPAXIHPBDH@Z
+  ??3@YAXPAX@Z
+  ;fixme-not-in-libcmt.lib; ??4?$_SpinWait@$00@details@Concurrency@@QAEAAV012@ABV012@@Z
+  ;fixme-not-in-libcmt.lib; ??4?$_SpinWait@$0A@@details@Concurrency@@QAEAAV012@ABV012@@Z
+  ??4SchedulerPolicy@Concurrency@@QAEAAV01@ABV01@@Z
+  ??4__non_rtti_object@std@@QAEAAV01@ABV01@@Z
+  ??4bad_cast@std@@QAEAAV01@ABV01@@Z
+  ??4bad_typeid@std@@QAEAAV01@ABV01@@Z
+  ??4exception@std@@QAEAAV01@ABV01@@Z
+  ??8type_info@@QBE_NABV0@@Z
+  ??9type_info@@QBE_NABV0@@Z
+  ??_7__non_rtti_object@std@@6B@
+  ??_7bad_cast@std@@6B@
+  ??_7bad_typeid@std@@6B@
+  ;fixme-not-in-libcmt.lib; ??_7exception@@6B@
+  ??_7exception@std@@6B@
+  ;fixme-not-in-libcmt.lib; ??_F?$_SpinWait@$00@details@Concurrency@@QAEXXZ
+  ;fixme-not-in-libcmt.lib; ??_F?$_SpinWait@$0A@@details@Concurrency@@QAEXXZ
+  ??_Fbad_cast@std@@QAEXXZ
+  ??_Fbad_typeid@std@@QAEXXZ
+  ??_U@YAPAXI@Z
+  ??_U@YAPAXIHPBDH@Z
+  ??_V@YAXPAX@Z
+  ?Alloc@Concurrency@@YAPAXI@Z
+  ?Block@Context@Concurrency@@SAXXZ
+  ?Create@CurrentScheduler@Concurrency@@SAXABVSchedulerPolicy@2@@Z
+  ?Create@Scheduler@Concurrency@@SAPAV12@ABVSchedulerPolicy@2@@Z
+  ?CreateResourceManager@Concurrency@@YAPAUIResourceManager@1@XZ
+  ?CreateScheduleGroup@CurrentScheduler@Concurrency@@SAPAVScheduleGroup@2@XZ
+  ?CurrentContext@Context@Concurrency@@SAPAV12@XZ
+  ?Detach@CurrentScheduler@Concurrency@@SAXXZ
+  ?DisableTracing@Concurrency@@YAJXZ
+  ?EnableTracing@Concurrency@@YAJXZ
+  ?Free@Concurrency@@YAXPAX@Z
+  ?Get@CurrentScheduler@Concurrency@@SAPAVScheduler@2@XZ
+  ?GetExecutionContextId@Concurrency@@YAIXZ
+  ?GetNumberOfVirtualProcessors@CurrentScheduler@Concurrency@@SAIXZ
+  ?GetOSVersion@Concurrency@@YA?AW4OSVersion@IResourceManager@1@XZ
+  ?GetPolicy@CurrentScheduler@Concurrency@@SA?AVSchedulerPolicy@2@XZ
+  ?GetPolicyValue@SchedulerPolicy@Concurrency@@QBEIW4PolicyElementKey@2@@Z
+  ?GetProcessorCount@Concurrency@@YAIXZ
+  ?GetProcessorNodeCount@Concurrency@@YAIXZ
+  ?GetSchedulerId@Concurrency@@YAIXZ
+  ?GetSharedTimerQueue@details@Concurrency@@YAPAXXZ
+  ?Id@Context@Concurrency@@SAIXZ
+  ?Id@CurrentScheduler@Concurrency@@SAIXZ
+  ?IsCurrentTaskCollectionCanceling@Context@Concurrency@@SA_NXZ
+  ?Log2@details@Concurrency@@YAKI@Z
+  ?Oversubscribe@Context@Concurrency@@SAX_N@Z
+  ?RegisterShutdownEvent@CurrentScheduler@Concurrency@@SAXPAX@Z
+  ?ResetDefaultSchedulerPolicy@Scheduler@Concurrency@@SAXXZ
+  ?ScheduleGroupId@Context@Concurrency@@SAIXZ
+  ?ScheduleTask@CurrentScheduler@Concurrency@@SAXP6AXPAX@Z0@Z
+  ?SetConcurrencyLimits@SchedulerPolicy@Concurrency@@QAEXII@Z
+  ?SetDefaultSchedulerPolicy@Scheduler@Concurrency@@SAXABVSchedulerPolicy@2@@Z
+  ?SetPolicyValue@SchedulerPolicy@Concurrency@@QAEIW4PolicyElementKey@2@I@Z
+  ?VirtualProcessorId@Context@Concurrency@@SAIXZ
+  ?Yield@Context@Concurrency@@SAXXZ
+  ?_Abort@_StructuredTaskCollection@details@Concurrency@@AAEXXZ
+  ?_Acquire@_NonReentrantBlockingLock@details@Concurrency@@QAEXXZ
+  ?_Acquire@_NonReentrantPPLLock@details@Concurrency@@QAEXPAX@Z
+  ?_Acquire@_ReentrantBlockingLock@details@Concurrency@@QAEXXZ
+  ?_Acquire@_ReentrantLock@details@Concurrency@@QAEXXZ
+  ?_Acquire@_ReentrantPPLLock@details@Concurrency@@QAEXPAX@Z
+  ?_AcquireRead@_ReaderWriterLock@details@Concurrency@@QAEXXZ
+  ?_AcquireWrite@_ReaderWriterLock@details@Concurrency@@QAEXXZ
+  ?_Cancel@_StructuredTaskCollection@details@Concurrency@@QAEXXZ
+  ?_Cancel@_TaskCollection@details@Concurrency@@QAEXXZ
+  ?_CheckTaskCollection@_UnrealizedChore@details@Concurrency@@IAEXXZ
+  ?_ConcRT_Assert@details@Concurrency@@YAXPBD0H@Z
+  ?_ConcRT_CoreAssert@details@Concurrency@@YAXPBD0H@Z
+  ?_ConcRT_DumpMessage@details@Concurrency@@YAXPB_WZZ
+  ?_ConcRT_Trace@details@Concurrency@@YAXHPB_WZZ
+  ?_Copy_str@exception@std@@AAEXPBD@Z
+  ?_DoYield@?$_SpinWait@$00@details@Concurrency@@IAEXXZ
+  ?_DoYield@?$_SpinWait@$0A@@details@Concurrency@@IAEXXZ
+  ?_IsCanceling@_StructuredTaskCollection@details@Concurrency@@QAE_NXZ
+  ?_IsCanceling@_TaskCollection@details@Concurrency@@QAE_NXZ
+  ?_Name_base@type_info@@CAPBDPBV1@PAU__type_info_node@@@Z
+  ?_Name_base_internal@type_info@@CAPBDPBV1@PAU__type_info_node@@@Z
+  ?_NumberOfSpins@?$_SpinWait@$00@details@Concurrency@@IAEKXZ
+  ?_NumberOfSpins@?$_SpinWait@$0A@@details@Concurrency@@IAEKXZ
+  ?_Release@_NonReentrantBlockingLock@details@Concurrency@@QAEXXZ
+  ?_Release@_NonReentrantPPLLock@details@Concurrency@@QAEXXZ
+  ?_Release@_ReentrantBlockingLock@details@Concurrency@@QAEXXZ
+  ?_Release@_ReentrantLock@details@Concurrency@@QAEXXZ
+  ?_Release@_ReentrantPPLLock@details@Concurrency@@QAEXXZ
+  ?_ReleaseRead@_ReaderWriterLock@details@Concurrency@@QAEXXZ
+  ?_ReleaseWrite@_ReaderWriterLock@details@Concurrency@@QAEXXZ
+  ?_Reset@?$_SpinWait@$00@details@Concurrency@@IAEXXZ
+  ?_Reset@?$_SpinWait@$0A@@details@Concurrency@@IAEXXZ
+  ?_RunAndWait@_StructuredTaskCollection@details@Concurrency@@QAG?AW4_TaskCollectionStatus@23@PAV_UnrealizedChore@23@@Z
+  ?_RunAndWait@_TaskCollection@details@Concurrency@@QAG?AW4_TaskCollectionStatus@23@PAV_UnrealizedChore@23@@Z
+  ?_Schedule@_StructuredTaskCollection@details@Concurrency@@QAEXPAV_UnrealizedChore@23@@Z
+  ?_Schedule@_TaskCollection@details@Concurrency@@QAEXPAV_UnrealizedChore@23@@Z
+  ?_SetSpinCount@?$_SpinWait@$00@details@Concurrency@@QAEXI@Z
+  ?_SetSpinCount@?$_SpinWait@$0A@@details@Concurrency@@QAEXI@Z
+  ?_ShouldSpinAgain@?$_SpinWait@$00@details@Concurrency@@IAE_NXZ
+  ?_ShouldSpinAgain@?$_SpinWait@$0A@@details@Concurrency@@IAE_NXZ
+  ?_SpinOnce@?$_SpinWait@$00@details@Concurrency@@QAE_NXZ
+  ?_SpinOnce@?$_SpinWait@$0A@@details@Concurrency@@QAE_NXZ
+  ?_SpinYield@Context@Concurrency@@SAXXZ
+  ?_Start@_Timer@details@Concurrency@@IAEXXZ
+  ?_Stop@_Timer@details@Concurrency@@IAEXXZ
+  ?_Tidy@exception@std@@AAEXXZ
+  ?_Trace_ppl_function@Concurrency@@YAXABU_GUID@@EW4ConcRT_EventType@1@@Z
+  ?_TryAcquire@_NonReentrantBlockingLock@details@Concurrency@@QAE_NXZ
+  ?_TryAcquire@_ReentrantBlockingLock@details@Concurrency@@QAE_NXZ
+  ?_TryAcquire@_ReentrantLock@details@Concurrency@@QAE_NXZ
+  ?_TryAcquireWrite@_ReaderWriterLock@details@Concurrency@@QAE_NXZ
+  ?_Type_info_dtor@type_info@@CAXPAV1@@Z
+  ?_Type_info_dtor_internal@type_info@@CAXPAV1@@Z
+  ?_UnderlyingYield@details@Concurrency@@YAXXZ
+  ?_ValidateExecute@@YAHP6GHXZ@Z
+  ?_ValidateRead@@YAHPBXI@Z
+  ?_ValidateWrite@@YAHPAXI@Z
+  ?_Value@_SpinCount@details@Concurrency@@SAIXZ
+  ?__ExceptionPtrAssign@@YAXPAXPBX@Z
+  ?__ExceptionPtrCompare@@YA_NPBX0@Z
+  ?__ExceptionPtrCopy@@YAXPAXPBX@Z
+  ?__ExceptionPtrCopyException@@YAXPAXPBX1@Z
+  ?__ExceptionPtrCreate@@YAXPAX@Z
+  ?__ExceptionPtrCurrentException@@YAXPAX@Z
+  ?__ExceptionPtrDestroy@@YAXPAX@Z
+  ?__ExceptionPtrRethrow@@YAXPBX@Z
+  __uncaught_exception
+  ?_inconsistency@@YAXXZ
+  ?_invalid_parameter@@YAXPBG00II@Z
+  ?_is_exception_typeof@@YAHABVtype_info@@PAU_EXCEPTION_POINTERS@@@Z
+  ?_name_internal_method@type_info@@QBEPBDPAU__type_info_node@@@Z
+  ?_open@@YAHPBDHH@Z
+  ?_query_new_handler@@YAP6AHI@ZXZ
+  ?_query_new_mode@@YAHXZ
+  ?_set_new_handler@@YAP6AHI@ZH@Z
+  ?_set_new_handler@@YAP6AHI@ZP6AHI@Z@Z
+  ?_set_new_mode@@YAHH@Z
+  ?_set_se_translator@@YAP6AXIPAU_EXCEPTION_POINTERS@@@ZH@Z
+  ?_set_se_translator@@YAP6AXIPAU_EXCEPTION_POINTERS@@@ZP6AXI0@Z@Z
+  ?_sopen@@YAHPBDHHH@Z
+  ?_type_info_dtor_internal_method@type_info@@QAEXXZ
+  ?_wopen@@YAHPB_WHH@Z
+  ?_wsopen@@YAHPB_WHHH@Z
+  ?before@type_info@@QBEHABV1@@Z
+  ?get_error_code@scheduler_resource_allocation_error@Concurrency@@QBEJXZ
+  ?lock@critical_section@Concurrency@@QAEXXZ
+  ?lock@reader_writer_lock@Concurrency@@QAEXXZ
+  ?lock_read@reader_writer_lock@Concurrency@@QAEXXZ
+  ?name@type_info@@QBEPBDPAU__type_info_node@@@Z
+  ?native_handle@critical_section@Concurrency@@QAEAAV12@XZ
+  ?raw_name@type_info@@QBEPBDXZ
+  ?reset@event@Concurrency@@QAEXXZ
+  ?set@event@Concurrency@@QAEXXZ
+  ?set_new_handler@@YAP6AXXZP6AXXZ@Z
+  ?set_terminate@@YAP6AXXZH@Z
+  ?set_terminate@@YAP6AXXZP6AXXZ@Z
+  ?set_unexpected@@YAP6AXXZH@Z
+  ?set_unexpected@@YAP6AXXZP6AXXZ@Z
+  ?swprintf@@YAHPAGIPBGZZ
+  ?swprintf@@YAHPA_WIPB_WZZ
+  ?terminate@@YAXXZ ;fixme-causes-trouble-with-version-in-libcmt.lib;
+  ?try_lock@critical_section@Concurrency@@QAE_NXZ
+  ?try_lock@reader_writer_lock@Concurrency@@QAE_NXZ
+  ?try_lock_read@reader_writer_lock@Concurrency@@QAE_NXZ
+  ?unexpected@@YAXXZ
+  ?unlock@critical_section@Concurrency@@QAEXXZ
+  ?unlock@reader_writer_lock@Concurrency@@QAEXXZ
+  ?vswprintf@@YAHPA_WIPB_WPAD@Z
+  ?wait@Concurrency@@YAXI@Z
+  ?wait@event@Concurrency@@QAEII@Z
+  ?wait_for_multiple@event@Concurrency@@SAIPAPAV12@I_NI@Z
+  ?what@exception@std@@UBEPBDXZ
+  $I10_OUTPUT
+  _CIacos
+  _CIasin
+  _CIatan
+  _CIatan2
+  _CIcos
+  _CIcosh
+  _CIexp
+  _CIfmod
+  _CIlog
+  _CIlog10
+  _CIpow
+  _CIsin
+  _CIsinh
+  _CIsqrt
+  _CItan
+  _CItanh
+  _CRT_RTC_INIT
+  _CRT_RTC_INITW
+  _CreateFrameInfo
+  _CxxThrowException
+  _EH_prolog
+  _FindAndUnlinkFrame
+  _Getdays
+  _Getmonths
+  _Gettnames
+  _HUGE
+  _IsExceptionObjectToBeDestroyed
+  _NLG_Dispatch2
+  _NLG_Return
+  _NLG_Return2
+  _Strftime
+  _XcptFilter
+  __AdjustPointer
+  __BuildCatchObject
+  __BuildCatchObjectHelper
+  __CppXcptFilter
+  __CxxCallUnwindDelDtor
+  __CxxCallUnwindDtor
+  __CxxCallUnwindStdDelDtor
+  __CxxCallUnwindVecDtor
+  __CxxDetectRethrow
+  __CxxExceptionFilter
+  __CxxFrameHandler
+  __CxxFrameHandler2
+  __CxxFrameHandler3
+  __CxxLongjmpUnwind
+  __CxxQueryExceptionSize
+  __CxxRegisterExceptionObject
+  __CxxUnregisterExceptionObject
+  __DestructExceptionObject
+  __FrameUnwindFilter
+  __RTCastToVoid
+  __RTDynamicCast
+  __RTtypeid
+  __STRINGTOLD
+  __STRINGTOLD_L
+  __TypeMatch
+  ___lc_codepage_func
+  ___lc_collate_cp_func
+  ___lc_handle_func
+  ___mb_cur_max_func
+  ___mb_cur_max_l_func
+  ___setlc_active_func
+  ___unguarded_readlc_active_add_func
+  __argc
+  __argv
+  __badioinfo
+  __clean_type_info_names_internal
+  __control87_2
+  __create_locale
+  __crtCompareStringA
+  __crtCompareStringW
+  __crtLCMapStringA
+  __crtLCMapStringW
+  __daylight
+  __doserrno
+  __dstbias
+  ___fls_getvalue@4
+  ___fls_setvalue@8
+  __fpecode
+  __free_locale
+  __get_current_locale
+  __get_flsindex
+ ;fixme?; __get_tlsindex
+  __initenv
+  __iob_func
+  __isascii
+  __iscsym
+  __iscsymf
+  __iswcsym
+  __iswcsymf
+  __lconv
+  __lconv_init
+  __libm_sse2_acos
+  __libm_sse2_acosf
+  __libm_sse2_asin
+  __libm_sse2_asinf
+  __libm_sse2_atan
+  __libm_sse2_atan2
+  __libm_sse2_atanf
+  __libm_sse2_cos
+  __libm_sse2_cosf
+  __libm_sse2_exp
+  __libm_sse2_expf
+  __libm_sse2_log
+  __libm_sse2_log10
+  __libm_sse2_log10f
+  __libm_sse2_logf
+  __libm_sse2_pow
+  __libm_sse2_powf
+  __libm_sse2_sin
+  __libm_sse2_sinf
+  __libm_sse2_tan
+  __libm_sse2_tanf
+  __mb_cur_max
+ ;fixme?; __p___argc
+ ;fixme?; __p___argv
+ ;fixme?; __p___initenv
+ ;fixme?; __p___mb_cur_max
+ ;fixme?; __p___wargv
+ ;fixme?; __p___winitenv
+ ;fixme?; __p__acmdln
+ ;fixme?; __p__commode
+ ;fixme?; __p__daylight
+ ;fixme?; __p__dstbias
+ ;fixme?; __p__environ
+ ;fixme?; __p__fmode
+ ;fixme?; __p__iob
+ ;fixme?; __p__mbcasemap
+ ;fixme?; __p__mbctype
+ ;fixme?; __p__pctype
+ ;fixme?; __p__pgmptr
+ ;fixme?; __p__pwctype
+ ;fixme?; __p__timezone
+ ;fixme?; __p__tzname
+ ;fixme?; __p__wcmdln
+ ;fixme?; __p__wenviron
+ ;fixme?; __p__wpgmptr
+
+  __pctype_func
+  __pioinfo
+  __pwctype_func
+  __pxcptinfoptrs
+  __report_gsfailure
+  __set_app_type
+  __set_flsgetvalue
+  __setlc_active
+ ;fixme?; __setusermatherr
+  __strncnt
+  __swprintf_l
+  __sys_errlist
+  __sys_nerr
+  __threadhandle
+  __threadid
+  __timezone
+  __toascii
+  __tzname
+  __unDName
+  __unDNameEx
+  __unDNameHelper
+  __unguarded_readlc_active
+  __vswprintf_l
+  __wargv
+  __wcserror
+  __wcserror_s
+  __wcsncnt
+ ;fixme?; __wgetmainargs
+  __winitenv
+  _abnormal_termination
+  _abs64
+  _access
+  _access_s
+  _acmdln
+  _aligned_free
+  _aligned_malloc
+  _aligned_msize
+  _aligned_offset_malloc
+  _aligned_offset_realloc
+  _aligned_offset_recalloc
+  _aligned_realloc
+  _aligned_recalloc
+  _amsg_exit
+  _assert
+  _atodbl
+  _atodbl_l
+  _atof_l
+  _atoflt
+  _atoflt_l
+  _atoi64
+  _atoi64_l
+  _atoi_l
+  _atol_l
+  _atoldbl
+  _atoldbl_l
+  _beep
+  _beginthread
+  _beginthreadex
+  _byteswap_uint64
+  _byteswap_ulong
+  _byteswap_ushort
+  _c_exit
+  _cabs
+  _callnewh
+  _calloc_crt
+  _cexit
+  _cgets
+  _cgets_s
+  _cgetws
+  _cgetws_s
+  _chdir
+  _chdrive
+  _chgsign
+  _chkesp
+  _chmod
+  _chsize
+  _chsize_s
+  _clearfp
+  _close
+  _commit
+  ;fixme?; _commode
+  _configthreadlocale
+  _control87
+  _controlfp
+  _controlfp_s
+  _copysign
+  _cprintf
+  _cprintf_l
+  _cprintf_p
+  _cprintf_p_l
+  _cprintf_s
+  _cprintf_s_l
+  _cputs
+  _cputws
+  _creat
+  _create_locale
+  _crt_debugger_hook
+  _cscanf
+  _cscanf_l
+  _cscanf_s
+  _cscanf_s_l
+  _ctime32
+  _ctime32_s
+  _ctime64
+  _ctime64_s
+  _cwait
+  _cwprintf
+  _cwprintf_l
+  _cwprintf_p
+  _cwprintf_p_l
+  _cwprintf_s
+  _cwprintf_s_l
+  _cwscanf
+  _cwscanf_l
+  _cwscanf_s
+  _cwscanf_s_l
+  _daylight
+  _difftime32
+  _difftime64
+  _dosmaperr
+  _dstbias
+  _dup
+  _dup2
+  _dupenv_s
+  _ecvt
+  _ecvt_s
+  _encoded_null
+  _endthread
+  _endthreadex
+  _environ
+  _eof
+  _errno
+  _except_handler2
+  _except_handler3
+ ;fixme?; _except_handler4_common
+  _execl
+  _execle
+  _execlp
+  _execlpe
+  _execv
+  _execve
+  _execvp
+  _execvpe
+  _exit
+  _expand
+  _fclose_nolock
+  _fcloseall
+  _fcvt
+  _fcvt_s
+  _fdopen
+  _fflush_nolock
+  _fgetchar
+  _fgetwc_nolock
+  _fgetwchar
+  _filbuf
+  _filelength
+  _filelengthi64
+  _fileno
+  _findclose
+  _findfirst32
+  _findfirst32i64
+  _findfirst64
+  _findfirst64i32
+  _findnext32
+  _findnext32i64
+  _findnext64
+  _findnext64i32
+  _finite
+  _flsbuf
+  _flushall
+  ;fixme?; _fmode
+  _fpclass
+  _fpieee_flt
+  _fpreset
+  _fprintf_l
+  _fprintf_p
+  _fprintf_p_l
+  _fprintf_s_l
+  _fputchar
+  _fputwc_nolock
+  _fputwchar
+  _fread_nolock
+  _fread_nolock_s
+  _free_locale
+  _freea
+  _freea_s
+  _freefls
+  _fscanf_l
+  _fscanf_s_l
+  _fseek_nolock
+  _fseeki64
+  _fseeki64_nolock
+  _fsopen
+  _fstat32
+  _fstat32i64
+  _fstat64
+  _fstat64i32
+  _ftell_nolock
+  _ftelli64
+  _ftelli64_nolock
+  _ftime32
+  _ftime32_s
+  _ftime64
+  _ftime64_s
+  _ftol
+  _fullpath
+  _futime32
+  _futime64
+  _fwprintf_l
+  _fwprintf_p
+  _fwprintf_p_l
+  _fwprintf_s_l
+  _fwrite_nolock
+  _fwscanf_l
+  _fwscanf_s_l
+  _gcvt
+  _gcvt_s
+  _get_current_locale
+  _get_daylight
+  _get_doserrno
+  _get_dstbias
+  _get_errno
+  _get_fmode
+  _get_heap_handle
+  _get_invalid_parameter_handler
+  _get_osfhandle
+  _get_output_format
+  _get_pgmptr
+  _get_printf_count_output
+  _get_purecall_handler
+  _get_terminate
+  _get_timezone
+  _get_tzname
+  _get_unexpected
+  _get_wpgmptr
+  _getc_nolock
+  _getch
+  _getch_nolock
+  _getche
+  _getche_nolock
+  _getcwd
+  _getdcwd
+  _getdcwd_nolock
+  _getdiskfree
+  _getdllprocaddr
+  _getdrive
+  _getdrives
+  _getmaxstdio
+  _getmbcp
+  _getpid
+  _getptd
+  _getsystime
+  _getw
+  _getwch
+  _getwch_nolock
+  _getwche
+  _getwche_nolock
+  _getws
+  _getws_s
+  _global_unwind2
+  _gmtime32
+  _gmtime32_s
+  _gmtime64
+  _gmtime64_s
+  _heapadd
+  _heapchk
+  _heapmin
+  _heapset
+  _heapused
+  _heapwalk
+  _hypot
+  _hypotf
+  _i64toa
+  _i64toa_s
+  _i64tow
+  _i64tow_s
+  _initptd
+ ;fixme?; _initterm
+  _initterm_e
+  _inp
+  _inpd
+  _inpw
+  _invalid_parameter
+  _invalid_parameter_noinfo
+  _invalid_parameter_noinfo_noreturn
+  _invoke_watson
+  _iob
+  _isalnum_l
+  _isalpha_l
+  _isatty
+  _iscntrl_l
+  _isctype
+  _isctype_l
+  _isdigit_l
+  _isgraph_l
+  _isleadbyte_l
+  _islower_l
+  _ismbbalnum
+  _ismbbalnum_l
+  _ismbbalpha
+  _ismbbalpha_l
+  _ismbbgraph
+  _ismbbgraph_l
+  _ismbbkalnum
+  _ismbbkalnum_l
+  _ismbbkana
+  _ismbbkana_l
+  _ismbbkprint
+  _ismbbkprint_l
+  _ismbbkpunct
+  _ismbbkpunct_l
+  _ismbblead
+  _ismbblead_l
+  _ismbbprint
+  _ismbbprint_l
+  _ismbbpunct
+  _ismbbpunct_l
+  _ismbbtrail
+  _ismbbtrail_l
+  _ismbcalnum
+  _ismbcalnum_l
+  _ismbcalpha
+  _ismbcalpha_l
+  _ismbcdigit
+  _ismbcdigit_l
+  _ismbcgraph
+  _ismbcgraph_l
+  _ismbchira
+  _ismbchira_l
+  _ismbckata
+  _ismbckata_l
+  _ismbcl0
+  _ismbcl0_l
+  _ismbcl1
+  _ismbcl1_l
+  _ismbcl2
+  _ismbcl2_l
+  _ismbclegal
+  _ismbclegal_l
+  _ismbclower
+  _ismbclower_l
+  _ismbcprint
+  _ismbcprint_l
+  _ismbcpunct
+  _ismbcpunct_l
+  _ismbcspace
+  _ismbcspace_l
+  _ismbcsymbol
+  _ismbcsymbol_l
+  _ismbcupper
+  _ismbcupper_l
+  _ismbslead
+  _ismbslead_l
+  _ismbstrail
+  _ismbstrail_l
+  _isnan
+  _isprint_l
+  _ispunct_l
+  _isspace_l
+  _isupper_l
+  _iswalnum_l
+  _iswalpha_l
+  _iswcntrl_l
+  _iswcsym_l
+  _iswcsymf_l
+  _iswctype_l
+  _iswdigit_l
+  _iswgraph_l
+  _iswlower_l
+  _iswprint_l
+  _iswpunct_l
+  _iswspace_l
+  _iswupper_l
+  _iswxdigit_l
+  _isxdigit_l
+  _itoa
+  _itoa_s
+  _itow
+  _itow_s
+  _j0
+  _j1
+  _jn
+  _kbhit
+  _lfind
+  _lfind_s
+  _loaddll
+  _local_unwind2
+  _local_unwind4
+  _localtime32
+  _localtime32_s
+  _localtime64
+  _localtime64_s
+  _lock
+  _lock_file
+  _locking
+  _logb
+  _longjmpex
+  _lrotl
+  _lrotr
+  _lsearch
+  _lsearch_s
+  _lseek
+  _lseeki64
+  _ltoa
+  _ltoa_s
+  _ltow
+  _ltow_s
+  _makepath
+  _makepath_s
+  _malloc_crt
+  _mbbtombc
+  _mbbtombc_l
+  _mbbtype
+  _mbbtype_l
+  _mbcasemap
+  _mbccpy
+  _mbccpy_l
+  _mbccpy_s
+  _mbccpy_s_l
+  _mbcjistojms
+  _mbcjistojms_l
+  _mbcjmstojis
+  _mbcjmstojis_l
+  _mbclen
+  _mbclen_l
+  _mbctohira
+  _mbctohira_l
+  _mbctokata
+  _mbctokata_l
+  _mbctolower
+  _mbctolower_l
+  _mbctombb
+  _mbctombb_l
+  _mbctoupper
+  _mbctoupper_l
+  _mbctype
+  _mblen_l
+  _mbsbtype
+  _mbsbtype_l
+  _mbscat_s
+  _mbscat_s_l
+  _mbschr
+  _mbschr_l
+  _mbscmp
+  _mbscmp_l
+  _mbscoll
+  _mbscoll_l
+  _mbscpy_s
+  _mbscpy_s_l
+  _mbscspn
+  _mbscspn_l
+  _mbsdec
+  _mbsdec_l
+  _mbsicmp
+  _mbsicmp_l
+  _mbsicoll
+  _mbsicoll_l
+  _mbsinc
+  _mbsinc_l
+  _mbslen
+  _mbslen_l
+  _mbslwr
+  _mbslwr_l
+  _mbslwr_s
+  _mbslwr_s_l
+  _mbsnbcat
+  _mbsnbcat_l
+  _mbsnbcat_s
+  _mbsnbcat_s_l
+  _mbsnbcmp
+  _mbsnbcmp_l
+  _mbsnbcnt
+  _mbsnbcnt_l
+  _mbsnbcoll
+  _mbsnbcoll_l
+  _mbsnbcpy
+  _mbsnbcpy_l
+  _mbsnbcpy_s
+  _mbsnbcpy_s_l
+  _mbsnbicmp
+  _mbsnbicmp_l
+  _mbsnbicoll
+  _mbsnbicoll_l
+  _mbsnbset
+  _mbsnbset_l
+  _mbsnbset_s
+  _mbsnbset_s_l
+  _mbsncat
+  _mbsncat_l
+  _mbsncat_s
+  _mbsncat_s_l
+  _mbsnccnt
+  _mbsnccnt_l
+  _mbsncmp
+  _mbsncmp_l
+  _mbsncoll
+  _mbsncoll_l
+  _mbsncpy
+  _mbsncpy_l
+  _mbsncpy_s
+  _mbsncpy_s_l
+  _mbsnextc
+  _mbsnextc_l
+  _mbsnicmp
+  _mbsnicmp_l
+  _mbsnicoll
+  _mbsnicoll_l
+  _mbsninc
+  _mbsninc_l
+  _mbsnlen
+  _mbsnlen_l
+  _mbsnset
+  _mbsnset_l
+  _mbsnset_s
+  _mbsnset_s_l
+  _mbspbrk
+  _mbspbrk_l
+  _mbsrchr
+  _mbsrchr_l
+  _mbsrev
+  _mbsrev_l
+  _mbsset
+  _mbsset_l
+  _mbsset_s
+  _mbsset_s_l
+  _mbsspn
+  _mbsspn_l
+  _mbsspnp
+  _mbsspnp_l
+  _mbsstr
+  _mbsstr_l
+  _mbstok
+  _mbstok_l
+  _mbstok_s
+  _mbstok_s_l
+  _mbstowcs_l
+  _mbstowcs_s_l
+  _mbstrlen
+  _mbstrlen_l
+  _mbstrnlen
+  _mbstrnlen_l
+  _mbsupr
+  _mbsupr_l
+  _mbsupr_s
+  _mbsupr_s_l
+  _mbtowc_l
+  _memccpy
+  _memicmp
+  _memicmp_l
+  _mkdir
+  _mkgmtime32
+  _mkgmtime64
+  _mktemp
+  _mktemp_s
+  _mktime32
+  _mktime64
+  _msize
+  _nextafter
+  _open
+  _open_osfhandle
+  _outp
+  _outpd
+  _outpw
+  _pclose
+  _pctype
+  _pgmptr
+  _pipe
+  _popen
+  _printf_l
+  _printf_p
+  _printf_p_l
+  _printf_s_l
+  _purecall
+  _putch
+  _putch_nolock
+  _putenv
+  _putenv_s
+  _putw
+  _putwch
+  _putwch_nolock
+  _putws
+  _pwctype
+  _read
+  _realloc_crt
+  _recalloc
+  _recalloc_crt
+  _resetstkoflw
+  _rmdir
+  _rmtmp
+  _rotl
+  _rotl64
+  _rotr
+  _rotr64
+  _scalb
+  _scanf_l
+  _scanf_s_l
+  _scprintf
+  _scprintf_l
+  _scprintf_p
+  _scprintf_p_l
+  _scwprintf
+  _scwprintf_l
+  _scwprintf_p
+  _scwprintf_p_l
+  _searchenv
+  _searchenv_s
+  _seh_longjmp_unwind4
+  _seh_longjmp_unwind
+  _set_SSE2_enable
+  _set_abort_behavior
+  _set_controlfp
+  _set_doserrno
+  _set_errno
+  _set_error_mode
+  _set_fmode
+  _set_invalid_parameter_handler
+  _set_malloc_crt_max_wait
+  _set_output_format
+  _set_printf_count_output
+  _set_purecall_handler
+  _seterrormode
+  _setjmp
+  _setjmp3
+  _setmaxstdio
+  _setmbcp
+  _setmode
+  _setsystime
+  _sleep
+  _snprintf
+  _snprintf_c
+  _snprintf_c_l
+  _snprintf_l
+  _snprintf_s
+  _snprintf_s_l
+  _snscanf
+  _snscanf_l
+  _snscanf_s
+  _snscanf_s_l
+  _snwprintf
+  _snwprintf_l
+  _snwprintf_s
+  _snwprintf_s_l
+  _snwscanf
+  _snwscanf_l
+  _snwscanf_s
+  _snwscanf_s_l
+  _sopen
+  _sopen_s
+  _spawnl
+  _spawnle
+  _spawnlp
+  _spawnlpe
+  _spawnv
+  _spawnve
+  _spawnvp
+  _spawnvpe
+  _splitpath
+  _splitpath_s
+  _sprintf_l
+  _sprintf_p
+  _sprintf_p_l
+  _sprintf_s_l
+  _sscanf_l
+  _sscanf_s_l
+  _stat32
+  _stat32i64
+  _stat64
+  _stat64i32
+  _statusfp
+  _statusfp2
+  _strcoll_l
+  _strdate
+  _strdate_s
+  _strdup
+  _strerror
+  _strerror_s
+  _strftime_l
+  _stricmp
+  _stricmp_l
+  _stricoll
+  _stricoll_l
+  _strlwr
+  _strlwr_l
+  _strlwr_s
+  _strlwr_s_l
+  _strncoll
+  _strncoll_l
+  _strnicmp
+  _strnicmp_l
+  _strnicoll
+  _strnicoll_l
+  _strnset
+  _strnset_s
+  _strrev
+  _strset
+  _strset_s
+  _strtime
+  _strtime_s
+  _strtod_l
+  _strtoi64
+  _strtoi64_l
+  _strtol_l
+  _strtoui64
+  _strtoui64_l
+  _strtoul_l
+  _strupr
+  _strupr_l
+  _strupr_s
+  _strupr_s_l
+  _strxfrm_l
+  _swab
+  _swprintf
+  _swprintf_c
+  _swprintf_c_l
+  _swprintf_p
+  _swprintf_p_l
+  _swprintf_s_l
+  _swscanf_l
+  _swscanf_s_l
+  _sys_errlist
+  _sys_nerr
+  _tell
+  _telli64
+  _tempnam
+  _time32
+  _time64
+  _timezone
+  _tolower
+  _tolower_l
+  _toupper
+  _toupper_l
+  _towlower_l
+  _towupper_l
+  _tzname
+  _tzset
+  _ui64toa
+  _ui64toa_s
+  _ui64tow
+  _ui64tow_s
+  _ultoa
+  _ultoa_s
+  _ultow
+  _ultow_s
+  _umask
+  _umask_s
+  _ungetc_nolock
+  _ungetch
+  _ungetch_nolock
+  _ungetwc_nolock
+  _ungetwch
+  _ungetwch_nolock
+  _unlink
+  _unloaddll
+  _unlock
+  _unlock_file
+  _utime32
+  _utime64
+  _vcprintf
+  _vcprintf_l
+  _vcprintf_p
+  _vcprintf_p_l
+  _vcprintf_s
+  _vcprintf_s_l
+  _vcwprintf
+  _vcwprintf_l
+  _vcwprintf_p
+  _vcwprintf_p_l
+  _vcwprintf_s
+  _vcwprintf_s_l
+  _vfprintf_l
+  _vfprintf_p
+  _vfprintf_p_l
+  _vfprintf_s_l
+  _vfwprintf_l
+  _vfwprintf_p
+  _vfwprintf_p_l
+  _vfwprintf_s_l
+  _vprintf_l
+  _vprintf_p
+  _vprintf_p_l
+  _vprintf_s_l
+  _vscprintf
+  _vscprintf_l
+  _vscprintf_p
+  _vscprintf_p_l
+  _vscwprintf
+  _vscwprintf_l
+  _vscwprintf_p
+  _vscwprintf_p_l
+  _vsnprintf
+  _vsnprintf_c
+  _vsnprintf_c_l
+  _vsnprintf_l
+  _vsnprintf_s
+  _vsnprintf_s_l
+  _vsnwprintf
+  _vsnwprintf_l
+  _vsnwprintf_s
+  _vsnwprintf_s_l
+  _vsprintf_l
+  _vsprintf_p
+  _vsprintf_p_l
+  _vsprintf_s_l
+  _vswprintf
+  _vswprintf_c
+  _vswprintf_c_l
+  _vswprintf_l
+  _vswprintf_p
+  _vswprintf_p_l
+  _vswprintf_s_l
+  _vwprintf_l
+  _vwprintf_p
+  _vwprintf_p_l
+  _vwprintf_s_l
+  _waccess
+  _waccess_s
+  _wasctime
+  _wasctime_s
+  _wassert
+  _wchdir
+  _wchmod
+ ;fixme?; _wcmdln
+  _wcreat
+  _wcscoll_l
+  _wcsdup
+  _wcserror
+  _wcserror_s
+  _wcsftime_l
+  _wcsicmp
+  _wcsicmp_l
+  _wcsicoll
+  _wcsicoll_l
+  _wcslwr
+  _wcslwr_l
+  _wcslwr_s
+  _wcslwr_s_l
+  _wcsncoll
+  _wcsncoll_l
+  _wcsnicmp
+  _wcsnicmp_l
+  _wcsnicoll
+  _wcsnicoll_l
+  _wcsnset
+  _wcsnset_s
+  _wcsrev
+  _wcsset
+  _wcsset_s
+  _wcstod_l
+  _wcstoi64
+  _wcstoi64_l
+  _wcstol_l
+  _wcstombs_l
+  _wcstombs_s_l
+  _wcstoui64
+  _wcstoui64_l
+  _wcstoul_l
+  _wcsupr
+  _wcsupr_l
+  _wcsupr_s
+  _wcsupr_s_l
+  _wcsxfrm_l
+  _wctime32
+  _wctime32_s
+  _wctime64
+  _wctime64_s
+  _wctomb_l
+  _wctomb_s_l
+  _wctype
+  _wdupenv_s
+  _wenviron
+  _wexecl
+  _wexecle
+  _wexeclp
+  _wexeclpe
+  _wexecv
+  _wexecve
+  _wexecvp
+  _wexecvpe
+  _wfdopen
+  _wfindfirst32
+  _wfindfirst32i64
+  _wfindfirst64
+  _wfindfirst64i32
+  _wfindnext32
+  _wfindnext32i64
+  _wfindnext64
+  _wfindnext64i32
+  _wfopen
+  _wfopen_s
+  _wfreopen
+  _wfreopen_s
+  _wfsopen
+  _wfullpath
+  _wgetcwd
+  _wgetdcwd
+  _wgetdcwd_nolock
+  _wgetenv
+  _wgetenv_s
+  _wmakepath
+  _wmakepath_s
+  _wmkdir
+  _wmktemp
+  _wmktemp_s
+  _wopen
+  _wperror
+  _wpgmptr
+  _wpopen
+  _wprintf_l
+  _wprintf_p
+  _wprintf_p_l
+  _wprintf_s_l
+  _wputenv
+  _wputenv_s
+  _wremove
+  _wrename
+  _write
+  _wrmdir
+  _wscanf_l
+  _wscanf_s_l
+  _wsearchenv
+  _wsearchenv_s
+  _wsetlocale
+  _wsopen
+  _wsopen_s
+  _wspawnl
+  _wspawnle
+  _wspawnlp
+  _wspawnlpe
+  _wspawnv
+  _wspawnve
+  _wspawnvp
+  _wspawnvpe
+  _wsplitpath
+  _wsplitpath_s
+  _wstat32
+  _wstat32i64
+  _wstat64
+  _wstat64i32
+  _wstrdate
+  _wstrdate_s
+  _wstrtime
+  _wstrtime_s
+  _wsystem
+  _wtempnam
+  _wtmpnam
+  _wtmpnam_s
+  _wtof
+  _wtof_l
+  _wtoi
+  _wtoi64
+  _wtoi64_l
+  _wtoi_l
+  _wtol
+  _wtol_l
+  _wunlink
+  _wutime32
+  _wutime64
+  _y0
+  _y1
+  _yn
+  abort
+  abs
+  acos
+  asctime
+  asctime_s
+  asin
+  atan
+  atan2
+  atexit
+  atof
+  atoi
+  atol
+  bsearch
+  bsearch_s
+  btowc
+  calloc
+  ceil
+  clearerr
+  clearerr_s
+  clock
+  cos
+  cosh
+  div
+  exit
+  exp
+  fabs
+  fclose
+  feof
+  ferror
+  fflush
+  fgetc
+  fgetpos
+  fgets
+  fgetwc
+  fgetws
+  floor
+  fmod
+  fopen
+  fopen_s
+  fprintf
+  fprintf_s
+  fputc
+  fputs
+  fputwc
+  fputws
+  fread
+  fread_s
+  free
+  freopen
+  freopen_s
+  frexp
+  fscanf
+  fscanf_s
+  fseek
+  fsetpos
+  ftell
+  fwprintf
+  fwprintf_s
+  fwrite
+  fwscanf
+  fwscanf_s
+  getc
+  getchar
+  getenv
+  getenv_s
+  gets
+  gets_s
+  getwc
+  getwchar
+  is_wctype
+  isalnum
+  isalpha
+  iscntrl
+  isdigit
+  isgraph
+  isleadbyte
+  islower
+  isprint
+  ispunct
+  isspace
+  isupper
+  iswalnum
+  iswalpha
+  iswascii
+  iswcntrl
+  iswctype
+  iswdigit
+  iswgraph
+  iswlower
+  iswprint
+  iswpunct
+  iswspace
+  iswupper
+  iswxdigit
+  isxdigit
+  labs
+  ldexp
+  ldiv
+  llabs
+  lldiv
+  localeconv
+  log
+  log10
+  longjmp
+  malloc
+  mblen
+  mbrlen
+  mbrtowc
+  mbsrtowcs
+  mbsrtowcs_s
+  mbstowcs
+  mbstowcs_s
+  mbtowc
+  memchr
+  memcmp
+  memcpy
+  memcpy_s
+  memmove
+  memmove_s
+  memset
+  modf
+  perror
+  pow
+  printf
+  printf_s
+  putc
+  putchar
+  puts
+  putwc
+  putwchar
+  qsort
+  qsort_s
+  raise
+  rand
+  rand_s
+  realloc
+  remove
+  rename
+  rewind
+  scanf
+  scanf_s
+  setbuf
+  setlocale
+  setvbuf
+  signal
+  sin
+  sinh
+  sprintf
+  sprintf_s
+  sqrt
+  srand
+  sscanf
+  sscanf_s
+  strcat
+  strcat_s
+  strchr
+  strcmp
+  strcoll
+  strcpy
+  strcpy_s
+  strcspn
+  strerror
+  strerror_s
+  strftime
+  strlen
+  strncat
+  strncat_s
+  strncmp
+  strncpy
+  strncpy_s
+  strnlen
+  strpbrk
+  strrchr
+  strspn
+  strstr
+  strtod
+  strtok
+  strtok_s
+  strtol
+  strtoul
+  strxfrm
+  swprintf_s
+  swscanf
+  swscanf_s
+  system
+  tan
+  tanh
+  tmpfile
+  tmpfile_s
+  tmpnam
+  tmpnam_s
+  tolower
+  toupper
+  towlower
+  towupper
+  ungetc
+  ungetwc
+  vfprintf
+  vfprintf_s
+  vfwprintf
+  vfwprintf_s
+  vprintf
+  vprintf_s
+  vsprintf
+  vsprintf_s
+  vswprintf_s
+  vwprintf
+  vwprintf_s
+  wcrtomb
+  wcrtomb_s
+  wcscat
+  wcscat_s
+  wcschr
+  wcscmp
+  wcscoll
+  wcscpy
+  wcscpy_s
+  wcscspn
+  wcsftime
+  wcslen
+  wcsncat
+  wcsncat_s
+  wcsncmp
+  wcsncpy
+  wcsncpy_s
+  wcsnlen
+  wcspbrk
+  wcsrchr
+  wcsrtombs
+  wcsrtombs_s
+  wcsspn
+  wcsstr
+  wcstod
+  wcstok
+  wcstok_s
+  wcstol
+  wcstombs
+  wcstombs_s
+  wcstoul
+  wcsxfrm
+  wctob
+  wctomb
+  wctomb_s
+  wmemcpy_s
+  wmemmove_s
+  wprintf
+  wprintf_s
+  wscanf
+  wscanf_s
+
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-openssl-1.1plus.def b/src/VBox/Runtime/r3/win/VBoxRT-openssl-1.1plus.def
new file mode 100644
index 00000000..8787224f
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-openssl-1.1plus.def
@@ -0,0 +1,395 @@
+; $Id: VBoxRT-openssl-1.1plus.def $
+;; @file
+; IPRT - Windows OpenSSL exports we use outside VBoxRT (keep them few!).
+;
+; This file is appended to the architecture specific .def file.
+;
+
+;
+; Copyright (C) 2009-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+    ; ConsoleImpl.cpp uses this when VBOX_OPENSSL_FIPS is enabled.
+    FIPS_mode
+
+    ; VBoxVRDP.dll - secure.cpp
+    BIO_free
+    BIO_new_file
+    BN_bin2bn
+    BN_bn2bin
+    BN_CTX_free
+    BN_CTX_new
+    BN_free
+    BN_mod_exp
+    BN_new
+    BN_num_bits
+    BN_set_word
+    EVP_PKEY_get0_RSA
+    i2d_X509
+    MD5_Final
+    MD5_Init
+    MD5_Update
+    OBJ_obj2nid
+    PEM_read_bio_PrivateKey
+    PEM_read_bio_X509
+    RAND_bytes
+    RC4
+    RC4_set_key
+    RSA_free
+    RSA_generate_key_ex
+    RSA_get0_key
+    RSA_new
+    SHA1_Final
+    SHA1_Init
+    SHA1_Update
+    X509_free
+    X509_get_X509_PUBKEY
+    X509_PUBKEY_get0_param
+
+    ; VBoxVRDP.dll - tcp_vrdp.cpp
+    BIO_new_socket
+    BIO_test_flags
+    OPENSSL_init_ssl
+    SSL_accept
+    SSL_CTX_free
+    SSL_CTX_load_verify_locations
+    SSL_CTX_new
+    SSL_CTX_set_verify
+    SSL_CTX_use_certificate_file
+    SSL_CTX_use_PrivateKey_file
+    SSL_free
+    SSL_get_certificate
+    SSL_new
+    SSL_pending
+    SSL_read
+    SSL_set_bio
+    SSL_set_read_ahead
+    SSL_write
+    TLSv1_server_method
+    X509_get_issuer_name
+    X509_NAME_oneline
+
+    ; VDPluginCrypt.dll (if it wanted to use IPRT) - VDKeyStore.cpp:
+    EVP_aes_128_xts
+    EVP_aes_256_xts
+    EVP_CIPHER_CTX_free
+    EVP_CIPHER_CTX_new
+    EVP_DecryptFinal
+    EVP_DecryptInit
+    EVP_DecryptUpdate
+    EVP_EncryptFinal
+    EVP_EncryptInit
+    EVP_EncryptUpdate
+    EVP_MD_size
+    EVP_sha1
+    EVP_sha256
+    EVP_sha512
+    PKCS5_PBKDF2_HMAC
+    ;exported above: RAND_bytes
+
+    ; VDPluginCrypt.dll (if it wanted to use IPRT) - VDFilterCrypt.cpp:
+    ;exported above: EVP_aes_128_xts
+    ;exported above: EVP_aes_256_xts
+    ;exported above: EVP_CIPHER_CTX_free
+    ;exported above: EVP_CIPHER_CTX_new
+    ;exported above: EVP_DecryptFinal
+    ;exported above: EVP_DecryptInit
+    ;exported above: EVP_DecryptUpdate
+    ;exported above: EVP_EncryptFinal
+    ;exported above: EVP_EncryptInit
+    ;exported above: EVP_EncryptUpdate
+    ;exported above: RAND_bytes
+
+    ; vboxwebsrv needs SSL support.
+    ASN1_STRING_data
+    ASN1_STRING_get0_data
+    ASN1_STRING_to_UTF8
+    ;exported above: BIO_free
+    ;exported above: BIO_new_file
+    ;exported above: BIO_new_socket
+    BIO_read
+    BIO_write
+    CRYPTO_free
+    DH_check
+    DH_free
+    DH_generate_parameters
+    DH_generate_parameters_ex
+    DH_new
+    ERR_clear_error
+    ERR_error_string
+    ERR_error_string_n
+    ERR_get_error
+    ERR_peek_error
+    GENERAL_NAME_free
+    i2v_GENERAL_NAMES
+    OpenSSL_version_num
+    OPENSSL_init_crypto
+    ;exported above: OPENSSL_init_ssl
+    OPENSSL_sk_num
+    OPENSSL_sk_pop_free
+    OPENSSL_sk_value
+    PEM_read_bio_DHparams
+    RAND_load_file
+    RAND_pseudo_bytes
+    RAND_seed
+    RAND_status
+    ;exported above: RSA_free
+    RSA_generate_key
+    ;exported above: SSL_accept
+    SSL_clear
+    SSL_connect
+    SSL_ctrl
+    SSL_CTX_ctrl
+    ;exported above: SSL_CTX_free
+    SSL_CTX_get_cert_store
+    ;exported above: SSL_CTX_load_verify_locations
+    ;exported above: SSL_CTX_new
+    SSL_CTX_set_client_CA_list
+    SSL_CTX_set_default_passwd_cb
+    SSL_CTX_set_default_passwd_cb_userdata
+    SSL_CTX_set_default_verify_paths
+    SSL_CTX_set_options
+    SSL_CTX_set_session_id_context
+    ;exported above: SSL_CTX_set_verify
+    SSL_CTX_set_verify_depth
+    SSL_CTX_use_certificate_chain_file
+    ;exported above: SSL_CTX_use_PrivateKey_file
+    ;exported above: SSL_free
+    SSL_get_error
+    SSL_get_peer_certificate
+    SSL_get_verify_result
+    SSL_get1_session
+    SSL_is_init_finished
+    SSL_load_client_CA_file
+    ;exported above: SSL_new
+    SSL_peek
+    ;exported above: SSL_read
+    SSL_SESSION_free
+    ;exported above: SSL_set_bio
+    SSL_set_session
+    SSL_shutdown
+    SSL_want
+    ;exported above: SSL_write
+    TLS_method
+    ;exported above: X509_free
+    X509_get_ext_d2i
+    ;exported above: X509_get_issuer_name
+    X509_get_subject_name
+    X509_load_crl_file
+    X509_LOOKUP_file
+    X509_NAME_ENTRY_get_data
+    X509_NAME_get_entry
+    X509_NAME_get_index_by_NID
+    ;exported above: X509_NAME_oneline
+    X509_STORE_add_lookup
+    X509_STORE_CTX_get_current_cert
+    X509_STORE_CTX_get_error
+    X509_STORE_CTX_get_error_depth
+    X509_STORE_CTX_set_error
+    X509_STORE_set1_param
+    X509_STORE_set_flags
+    X509_verify_cert_error_string
+    X509_VERIFY_PARAM_free
+    X509_VERIFY_PARAM_new
+    X509_VERIFY_PARAM_set_flags
+    X509V3_conf_free
+
+    ; tstRTBigNum.cpp
+    BN_div
+    BN_mul
+    BN_mod_exp_simple
+    BN_ucmp
+
+    ; VBox-libtpms
+    BN_set_flags
+    BN_clear_free
+    BN_cmp
+    BN_dup
+    BN_sub
+    BN_add
+    BN_copy
+    RAND_add
+    BN_is_zero
+    BN_is_one
+    BN_value_one
+    BN_CTX_start
+    BN_CTX_get
+    BN_CTX_end
+    BN_mod_add
+    BN_mod_mul
+    BN_lshift
+    BN_mask_bits
+    BN_rshift
+    BN_mod_inverse
+    RSA_size
+    RSA_set0_key
+    RSA_get0_factors
+    RSA_public_encrypt
+    RSA_private_encrypt
+    RSA_private_decrypt
+    RSA_sign
+    RSA_verify
+    RSA_padding_add_PKCS1_type_1
+    RSA_padding_add_PKCS1_type_2
+    RSA_padding_check_PKCS1_type_1
+    RSA_padding_check_PKCS1_type_2
+    RSA_padding_add_PKCS1_OAEP
+    RSA_padding_check_PKCS1_OAEP
+    ERR_get_error_line_data
+    AES_set_encrypt_key
+    AES_set_decrypt_key
+    AES_decrypt
+    AES_encrypt
+    AES_cbc_encrypt
+    AES_ofb128_encrypt
+    SHA256_Init
+    SHA256_Update
+    SHA256_Final
+    SHA384_Init
+    SHA384_Update
+    SHA384_Final
+    SHA512_Init
+    SHA512_Update
+    SHA512_Final
+    EC_GROUP_free
+    EC_GROUP_set_generator
+    EC_GROUP_new_curve_GFp
+    EC_POINT_new
+    EC_POINT_free
+    EC_POINT_clear_free
+    EC_POINT_set_affine_coordinates
+    EC_POINT_get_affine_coordinates
+    EC_POINT_add
+    EC_POINTs_mul
+    EC_POINT_mul
+    Camellia_set_key
+    Camellia_encrypt
+    Camellia_decrypt
+    DES_ecb3_encrypt
+    DES_set_key_unchecked
+
+    ; VBox-libssh
+    BIO_ctrl
+    BIO_new
+    BIO_new_mem_buf
+    BIO_s_mem
+    BN_bn2hex
+    BN_is_bit_set
+    d2i_DSA_SIG
+    d2i_ECDSA_SIG
+    DH_compute_key
+    DH_generate_key
+    DH_get0_key
+    DH_get0_pqg
+    DH_set0_key
+    DH_set0_pqg
+    DH_size
+    DSA_free
+    DSA_generate_key
+    DSA_generate_parameters_ex
+    DSA_get0_key
+    DSA_get0_pqg
+    DSA_new
+    DSA_set0_key
+    DSA_set0_pqg
+    DSA_SIG_free
+    DSA_SIG_get0
+    DSA_SIG_new
+    DSA_SIG_set0
+    DSA_size
+    EC_GROUP_cmp
+    EC_GROUP_get_curve_name
+    EC_GROUP_get_degree
+    EC_KEY_dup
+    EC_KEY_free
+    EC_KEY_generate_key
+    EC_KEY_get0_group
+    EC_KEY_get0_private_key
+    EC_KEY_get0_public_key
+    EC_KEY_new_by_curve_name
+    EC_KEY_set_asn1_flag
+    EC_KEY_set_private_key
+    EC_KEY_set_public_key
+    EC_POINT_cmp
+    EC_POINT_oct2point
+    EC_POINT_point2oct
+    ECDH_compute_key
+    ECDSA_SIG_free
+    ECDSA_SIG_get0
+    ECDSA_SIG_new
+    ECDSA_SIG_set0
+    EVP_aes_128_cbc
+    EVP_aes_128_ctr
+    EVP_aes_128_gcm
+    EVP_aes_192_cbc
+    EVP_aes_192_ctr
+    EVP_aes_256_cbc
+    EVP_aes_256_ctr
+    EVP_aes_256_gcm
+    EVP_CIPHER_CTX_ctrl
+    EVP_CIPHER_CTX_reset
+    EVP_CIPHER_CTX_set_padding
+    EVP_DecryptInit_ex
+    EVP_DigestFinal
+    EVP_DigestInit
+    EVP_DigestInit_ex
+    EVP_DigestSignFinal
+    EVP_DigestSignInit
+    EVP_DigestUpdate
+    EVP_DigestVerifyFinal
+    EVP_DigestVerifyInit
+    EVP_EncryptInit_ex
+    EVP_MD_CTX_free
+    EVP_MD_CTX_new
+    EVP_MD_CTX_reset
+    EVP_md5
+    EVP_PKEY_base_id
+    EVP_PKEY_free
+    EVP_PKEY_get1_DSA
+    EVP_PKEY_get1_EC_KEY
+    EVP_PKEY_get1_RSA
+    EVP_PKEY_new
+    EVP_PKEY_set1_DSA
+    EVP_PKEY_set1_EC_KEY
+    EVP_PKEY_set1_RSA
+    EVP_PKEY_size
+    EVP_sha384
+    HMAC_CTX_free
+    HMAC_CTX_new
+    HMAC_Final
+    HMAC_Init_ex
+    HMAC_Update
+    i2d_DSA_SIG
+    i2d_ECDSA_SIG
+    OpenSSL_version
+    PEM_write_bio_PrivateKey
+    RSA_get0_crt_params
+    RSA_set0_crt_params
+    RSA_set0_factors
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-openssl-3.0.def b/src/VBox/Runtime/r3/win/VBoxRT-openssl-3.0.def
new file mode 100644
index 00000000..ea9407a8
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-openssl-3.0.def
@@ -0,0 +1,430 @@
+; $Id: VBoxRT-openssl-3.0.def $
+;; @file
+; IPRT - Windows OpenSSL exports we use outside VBoxRT (keep them few!).
+;
+; This file is appended to the architecture specific .def file.
+;
+
+;
+; Copyright (C) 2009-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+    ; VBoxVRDP.dll - secure.cpp
+    BIO_free
+    BIO_new_file
+    BN_bin2bn
+    BN_bn2bin
+    BN_CTX_free
+    BN_CTX_new
+    BN_free
+    BN_mod_exp
+    BN_new
+    BN_num_bits
+    BN_set_word
+    EVP_PKEY_get0_RSA
+    i2d_X509
+    MD5_Final
+    MD5_Init
+    MD5_Update
+    OBJ_obj2nid
+    PEM_read_bio_PrivateKey
+    PEM_read_bio_X509
+    RAND_bytes
+    RC4
+    RC4_set_key
+    RSA_free
+    RSA_generate_key_ex
+    RSA_get0_key
+    RSA_new
+    SHA1_Final
+    SHA1_Init
+    SHA1_Update
+    X509_free
+    X509_get_X509_PUBKEY
+    X509_PUBKEY_get0_param
+
+    ; VBoxVRDP.dll - tcp_vrdp.cpp
+    BIO_new_socket
+    BIO_test_flags
+    OPENSSL_init_ssl
+    SSL_accept
+    SSL_CTX_free
+    SSL_CTX_load_verify_locations
+    SSL_CTX_new
+    SSL_CTX_set_verify
+    SSL_CTX_use_certificate_file
+    SSL_CTX_use_PrivateKey_file
+    SSL_free
+    SSL_get_certificate
+    SSL_new
+    SSL_pending
+    SSL_read
+    SSL_set_bio
+    SSL_set_read_ahead
+    SSL_write
+    TLSv1_server_method
+    X509_get_issuer_name
+    X509_NAME_oneline
+
+    ; VDPluginCrypt.dll (if it wanted to use IPRT) - VDKeyStore.cpp:
+    EVP_aes_128_xts
+    EVP_aes_256_xts
+    EVP_CIPHER_CTX_free
+    EVP_CIPHER_CTX_new
+    EVP_DecryptFinal
+    EVP_DecryptInit
+    EVP_DecryptUpdate
+    EVP_EncryptFinal
+    EVP_EncryptInit
+    EVP_EncryptUpdate
+    EVP_MD_get_size
+    EVP_sha1
+    EVP_sha256
+    EVP_sha512
+    PKCS5_PBKDF2_HMAC
+    ;exported above: RAND_bytes
+
+    ; VDPluginCrypt.dll (if it wanted to use IPRT) - VDFilterCrypt.cpp:
+    ;exported above: EVP_aes_128_xts
+    ;exported above: EVP_aes_256_xts
+    ;exported above: EVP_CIPHER_CTX_free
+    ;exported above: EVP_CIPHER_CTX_new
+    ;exported above: EVP_DecryptFinal
+    ;exported above: EVP_DecryptInit
+    ;exported above: EVP_DecryptUpdate
+    ;exported above: EVP_EncryptFinal
+    ;exported above: EVP_EncryptInit
+    ;exported above: EVP_EncryptUpdate
+    ;exported above: RAND_bytes
+
+    ; vboxwebsrv needs SSL support.
+    ASN1_STRING_get0_data
+    ASN1_STRING_to_UTF8
+    ;exported above: BIO_free
+    ;exported above: BIO_new_file
+    ;exported above: BIO_new_socket
+    BIO_read
+    BIO_write
+    CRYPTO_free
+    DH_check
+    DH_free
+    DH_generate_parameters
+    DH_generate_parameters_ex
+    DH_new
+    ERR_clear_error
+    ERR_error_string
+    ERR_error_string_n
+    ERR_get_error
+    ERR_peek_error
+    GENERAL_NAME_free
+    i2v_GENERAL_NAMES
+    OpenSSL_version_num
+    OPENSSL_init_crypto
+    ;exported above: OPENSSL_init_ssl
+    OPENSSL_sk_num
+    OPENSSL_sk_pop_free
+    OPENSSL_sk_value
+    PEM_read_bio_DHparams
+    RAND_load_file
+    RAND_seed
+    RAND_status
+    ;exported above: RSA_free
+    RSA_generate_key
+    ;exported above: SSL_accept
+    SSL_clear
+    SSL_connect
+    SSL_ctrl
+    SSL_CTX_ctrl
+    ;exported above: SSL_CTX_free
+    SSL_CTX_get_cert_store
+    ;exported above: SSL_CTX_load_verify_locations
+    ;exported above: SSL_CTX_new
+    SSL_CTX_set_client_CA_list
+    SSL_CTX_set_default_passwd_cb
+    SSL_CTX_set_default_passwd_cb_userdata
+    SSL_CTX_set_default_verify_paths
+    SSL_CTX_set_options
+    SSL_CTX_set_session_id_context
+    ;exported above: SSL_CTX_set_verify
+    SSL_CTX_set_verify_depth
+    SSL_CTX_use_certificate_chain_file
+    ;exported above: SSL_CTX_use_PrivateKey_file
+    ;exported above: SSL_free
+    SSL_get_error
+    SSL_get1_peer_certificate
+    SSL_get_verify_result
+    SSL_get1_session
+    SSL_is_init_finished
+    SSL_load_client_CA_file
+    ;exported above: SSL_new
+    SSL_peek
+    ;exported above: SSL_read
+    SSL_SESSION_free
+    ;exported above: SSL_set_bio
+    SSL_set_session
+    SSL_shutdown
+    SSL_want
+    ;exported above: SSL_write
+    TLS_method
+    ;exported above: X509_free
+    X509_get_ext_d2i
+    ;exported above: X509_get_issuer_name
+    X509_get_subject_name
+    X509_load_crl_file
+    X509_LOOKUP_file
+    X509_NAME_ENTRY_get_data
+    X509_NAME_get_entry
+    X509_NAME_get_index_by_NID
+    ;exported above: X509_NAME_oneline
+    X509_STORE_add_lookup
+    X509_STORE_CTX_get_current_cert
+    X509_STORE_CTX_get_error
+    X509_STORE_CTX_get_error_depth
+    X509_STORE_CTX_set_error
+    X509_STORE_set1_param
+    X509_STORE_set_flags
+    X509_verify_cert_error_string
+    X509_VERIFY_PARAM_free
+    X509_VERIFY_PARAM_new
+    X509_VERIFY_PARAM_set_flags
+    X509V3_conf_free
+
+    ; tstRTBigNum.cpp
+    BN_div
+    BN_mul
+    BN_mod_exp_simple
+    BN_ucmp
+
+    ; VBox-libtpms
+    BN_set_flags
+    BN_clear_free
+    BN_cmp
+    BN_dup
+    BN_sub
+    BN_add
+    BN_copy
+    RAND_add
+    BN_is_zero
+    BN_is_one
+    BN_value_one
+    BN_CTX_start
+    BN_CTX_get
+    BN_CTX_end
+    BN_mod_add
+    BN_mod_mul
+    BN_lshift
+    BN_mask_bits
+    BN_rshift
+    BN_mod_inverse
+    RSA_size
+    RSA_set0_key
+    RSA_get0_factors
+    RSA_public_encrypt
+    RSA_private_encrypt
+    RSA_private_decrypt
+    RSA_sign
+    RSA_verify
+    RSA_padding_add_PKCS1_type_1
+    RSA_padding_add_PKCS1_type_2
+    RSA_padding_check_PKCS1_type_1
+    RSA_padding_check_PKCS1_type_2
+    RSA_padding_add_PKCS1_OAEP
+    RSA_padding_check_PKCS1_OAEP
+    ERR_get_error_line_data
+    AES_set_encrypt_key
+    AES_set_decrypt_key
+    AES_decrypt
+    AES_encrypt
+    AES_cbc_encrypt
+    AES_ofb128_encrypt
+    SHA256_Init
+    SHA256_Update
+    SHA256_Final
+    SHA384_Init
+    SHA384_Update
+    SHA384_Final
+    SHA512_Init
+    SHA512_Update
+    SHA512_Final
+    EC_GROUP_free
+    EC_GROUP_set_generator
+    EC_GROUP_new_curve_GFp
+    EC_POINT_new
+    EC_POINT_free
+    EC_POINT_clear_free
+    EC_POINT_set_affine_coordinates
+    EC_POINT_get_affine_coordinates
+    EC_POINT_add
+    EC_POINTs_mul
+    EC_POINT_mul
+    Camellia_set_key
+    Camellia_encrypt
+    Camellia_decrypt
+    DES_ecb3_encrypt
+    DES_set_key_unchecked
+
+    ; VBox-libssh
+    BIO_ctrl
+    BIO_new
+    BIO_new_mem_buf
+    BIO_s_mem
+    BN_bn2hex
+    BN_is_bit_set
+    d2i_DSA_SIG
+    d2i_ECDSA_SIG
+    DH_compute_key
+    DH_generate_key
+    DH_get0_key
+    DH_get0_pqg
+    DH_set0_key
+    DH_set0_pqg
+    DH_size
+    DSA_free
+    DSA_generate_key
+    DSA_generate_parameters_ex
+    DSA_get0_key
+    DSA_get0_pqg
+    DSA_new
+    DSA_set0_key
+    DSA_set0_pqg
+    DSA_SIG_free
+    DSA_SIG_get0
+    DSA_SIG_new
+    DSA_SIG_set0
+    DSA_size
+    EC_GROUP_cmp
+    EC_GROUP_get_curve_name
+    EC_GROUP_get_degree
+    EC_KEY_dup
+    EC_KEY_free
+    EC_KEY_generate_key
+    EC_KEY_get0_group
+    EC_KEY_get0_private_key
+    EC_KEY_get0_public_key
+    EC_KEY_new_by_curve_name
+    EC_KEY_set_asn1_flag
+    EC_KEY_set_private_key
+    EC_KEY_set_public_key
+    EC_POINT_cmp
+    EC_POINT_oct2point
+    EC_POINT_point2oct
+    ECDH_compute_key
+    ECDSA_SIG_free
+    ECDSA_SIG_get0
+    ECDSA_SIG_new
+    ECDSA_SIG_set0
+    EVP_aes_128_cbc
+    EVP_aes_128_ctr
+    EVP_aes_128_gcm
+    EVP_aes_192_cbc
+    EVP_aes_192_ctr
+    EVP_aes_256_cbc
+    EVP_aes_256_ctr
+    EVP_aes_256_gcm
+    EVP_CIPHER_CTX_ctrl
+    EVP_CIPHER_CTX_reset
+    EVP_CIPHER_CTX_set_padding
+    EVP_DecryptInit_ex
+    EVP_DigestFinal
+    EVP_DigestInit
+    EVP_DigestInit_ex
+    EVP_DigestSignFinal
+    EVP_DigestSignInit
+    EVP_DigestSignUpdate
+    EVP_DigestUpdate
+    EVP_DigestVerifyFinal
+    EVP_DigestVerifyInit
+    EVP_DigestVerifyUpdate
+    EVP_EncryptInit_ex
+    EVP_MD_CTX_free
+    EVP_MD_CTX_new
+    EVP_MD_CTX_reset
+    EVP_md5
+    EVP_PKEY_get_base_id
+    EVP_PKEY_free
+    EVP_PKEY_get1_DSA
+    EVP_PKEY_get1_EC_KEY
+    EVP_PKEY_get1_RSA
+    EVP_PKEY_new
+    EVP_PKEY_set1_DSA
+    EVP_PKEY_set1_EC_KEY
+    EVP_PKEY_set1_RSA
+    EVP_PKEY_get_size
+    EVP_sha384
+    HMAC_CTX_free
+    HMAC_CTX_new
+    HMAC_Final
+    HMAC_Init_ex
+    HMAC_Update
+    i2d_DSA_SIG
+    i2d_ECDSA_SIG
+    OpenSSL_version
+    PEM_write_bio_PrivateKey
+    RSA_get0_crt_params
+    RSA_set0_crt_params
+    RSA_set0_factors
+    ; since 0.10.5 also:
+    EC_KEY_up_ref
+    ENGINE_by_id
+    ENGINE_free
+    ENGINE_init
+    ENGINE_load_builtin_engines
+    EVP_default_properties_is_fips_enabled
+    EVP_PKEY_CTX_free
+    EVP_PKEY_CTX_new_from_name
+    EVP_PKEY_CTX_new_from_pkey
+    EVP_PKEY_CTX_set_params
+    EVP_PKEY_derive
+    EVP_PKEY_derive_init
+    EVP_PKEY_derive_set_peer
+    EVP_PKEY_eq
+    EVP_PKEY_fromdata
+    EVP_PKEY_fromdata_init
+    EVP_PKEY_generate
+    EVP_PKEY_get_bits
+    EVP_PKEY_get_bn_param
+    EVP_PKEY_keygen_init
+    EVP_PKEY_new_mac_key
+    EVP_PKEY_paramgen_init
+    EVP_PKEY_set_bn_param
+    EVP_PKEY_todata
+    EVP_PKEY_up_ref
+    OSSL_PARAM_BLD_free
+    OSSL_PARAM_BLD_new
+    OSSL_PARAM_BLD_push_BN
+    OSSL_PARAM_BLD_to_param
+    OSSL_PARAM_construct_end
+    OSSL_PARAM_construct_int
+    OSSL_PARAM_construct_uint
+    OSSL_PARAM_free
+    OSSL_PARAM_get_BN
+    OSSL_PARAM_locate_const
+    OSSL_PARAM_merge
+
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-win32.def b/src/VBox/Runtime/r3/win/VBoxRT-win32.def
new file mode 100644
index 00000000..261b3ce1
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-win32.def
@@ -0,0 +1,62 @@
+; $Id: VBoxRT-win32.def $
+;; @file
+; IPRT - Win32 ASM exports.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+EXPORTS
+    ASMMultU64ByU32DivByU32
+
+    RTTimeNanoTSLegacySyncInvarNoDelta
+    RTTimeNanoTSLFenceSyncInvarNoDelta
+    RTTimeNanoTSLegacyAsyncUseApicId
+    RTTimeNanoTSLegacyAsyncUseRdtscp
+    RTTimeNanoTSLegacyAsyncUseIdtrLim
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseApicId
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseRdtscp
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseIdtrLim
+    RTTimeNanoTSLFenceAsyncUseApicId
+    RTTimeNanoTSLFenceAsyncUseRdtscp
+    RTTimeNanoTSLFenceAsyncUseIdtrLim
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseApicId
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseRdtscp
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseIdtrLim
+
+    RTStrMemFind32
+
+    ; Export aliases for noexcept affected methods.
+    ?setConsumerCallback@RTCRestBinaryResponse@@QAEXP6AHPAV1@PBXII_K2@_EPAX@Z=?setConsumerCallback@RTCRestBinaryResponse@@QAEXP6AHPAV1@PBXII_K2@ZPAX@Z   ; before-noexcept ; (public: void __thiscall RTCRestBinaryResponse::setConsumerCallback(int (__cdecl*)(class RTCRestBinaryResponse *,void const *,unsigned int,unsigned int,unsigned __int64,unsigned __int64) noexcept,void *))
+    ?setConsumerCallback@RTCRestBinaryResponse@@QAEXP6AHPAV1@PBXII_K2@ZPAX@Z=?setConsumerCallback@RTCRestBinaryResponse@@QAEXP6AHPAV1@PBXII_K2@_EPAX@Z   ; after-noexcept  ; (public: void __thiscall RTCRestBinaryResponse::setConsumerCallback(int (__cdecl*)(class RTCRestBinaryResponse *,void const *,unsigned int,unsigned int,unsigned __int64,unsigned __int64),void *))
+    ?setProducerCallback@RTCRestBinaryParameter@@QAEXP6AHPAV1@PAXI_KPAI@_E12@Z=?setProducerCallback@RTCRestBinaryParameter@@QAEXP6AHPAV1@PAXI_KPAI@Z12@Z ; before-noexcept ; (public: void __thiscall RTCRestBinaryParameter::setProducerCallback(int (__cdecl*)(class RTCRestBinaryParameter *,void *,unsigned int,unsigned __int64,unsigned int *) noexcept,void *,unsigned __int64))
+    ?setProducerCallback@RTCRestBinaryParameter@@QAEXP6AHPAV1@PAXI_KPAI@Z12@Z=?setProducerCallback@RTCRestBinaryParameter@@QAEXP6AHPAV1@PAXI_KPAI@_E12@Z ; after-noexcept  ; (public: void __thiscall RTCRestBinaryParameter::setProducerCallback(int (__cdecl*)(class RTCRestBinaryParameter *,void *,unsigned int,unsigned __int64,unsigned int *),void *,unsigned __int64))
+
diff --git a/src/VBox/Runtime/r3/win/VBoxRT-win64.def b/src/VBox/Runtime/r3/win/VBoxRT-win64.def
new file mode 100644
index 00000000..e3a83833
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/VBoxRT-win64.def
@@ -0,0 +1,74 @@
+; $Id: VBoxRT-win64.def $
+;; @file
+; IPRT - Win64 ASM exports.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+EXPORTS
+    ASMAtomicBitClear
+    ASMAtomicBitToggle
+    ASMAtomicBitTestAndToggle
+    ASMBitFirstClear
+    ASMBitFirstSet
+    ASMAtomicReadU64
+    ASMAtomicXchgU8
+    ASMAtomicXchgU16
+    ASMGetFlags
+    ASMProbeReadByte
+    ASMSetFlags
+    ASMMultU64ByU32DivByU32
+    ASMNopPause
+
+    RTTimeNanoTSLegacySyncInvarNoDelta
+    RTTimeNanoTSLFenceSyncInvarNoDelta
+    RTTimeNanoTSLegacyAsyncUseApicId
+    RTTimeNanoTSLegacyAsyncUseRdtscp
+    RTTimeNanoTSLegacyAsyncUseIdtrLim
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseApicId
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseRdtscp
+    RTTimeNanoTSLegacySyncInvarWithDeltaUseIdtrLim
+    RTTimeNanoTSLFenceAsyncUseApicId
+    RTTimeNanoTSLFenceAsyncUseRdtscp
+    RTTimeNanoTSLFenceAsyncUseIdtrLim
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseApicId
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseRdtscp
+    RTTimeNanoTSLFenceSyncInvarWithDeltaUseIdtrLim
+
+    RTStrMemFind32
+
+    ; Export aliases for noexcept affected methods.
+    ?setConsumerCallback@RTCRestBinaryResponse@@QEAAXP6AHPEAV1@PEBX_KI22@_EPEAX@Z=?setConsumerCallback@RTCRestBinaryResponse@@QEAAXP6AHPEAV1@PEBX_KI22@ZPEAX@Z     ; before-noexcept ; (public: void __cdecl RTCRestBinaryResponse::setConsumerCallback(int (__cdecl*)(class RTCRestBinaryResponse * __ptr64,void const * __ptr64,unsigned __int64,unsigned int,unsigned __int64,unsigned __int64) noexcept,void * __ptr64) __ptr64
+    ?setConsumerCallback@RTCRestBinaryResponse@@QEAAXP6AHPEAV1@PEBX_KI22@ZPEAX@Z=?setConsumerCallback@RTCRestBinaryResponse@@QEAAXP6AHPEAV1@PEBX_KI22@_EPEAX@Z     ; after-noexcept  ; (public: void __cdecl RTCRestBinaryResponse::setConsumerCallback(int (__cdecl*)(class RTCRestBinaryResponse * __ptr64,void const * __ptr64,unsigned __int64,unsigned int,unsigned __int64,unsigned __int64),void * __ptr64) __ptr64)
+    ?setProducerCallback@RTCRestBinaryParameter@@QEAAXP6AHPEAV1@PEAX_K2PEA_K@_E12@Z=?setProducerCallback@RTCRestBinaryParameter@@QEAAXP6AHPEAV1@PEAX_K2PEA_K@Z12@Z ; before-noexcept ; (public: void __cdecl RTCRestBinaryParameter::setProducerCallback(int (__cdecl*)(class RTCRestBinaryParameter * __ptr64,void * __ptr64,unsigned __int64,unsigned __int64,unsigned __int64 * __ptr64) noexcept,void * __ptr64,unsigned __int64) __ptr64)
+    ?setProducerCallback@RTCRestBinaryParameter@@QEAAXP6AHPEAV1@PEAX_K2PEA_K@Z12@Z=?setProducerCallback@RTCRestBinaryParameter@@QEAAXP6AHPEAV1@PEAX_K2PEA_K@_E12@Z ; after-noexcept  ; (public: void __cdecl RTCRestBinaryParameter::setProducerCallback(int (__cdecl*)(class RTCRestBinaryParameter * __ptr64,void * __ptr64,unsigned __int64,unsigned __int64,unsigned __int64 * __ptr64),void * __ptr64,unsigned __int64) __ptr64)
+
diff --git a/src/VBox/Runtime/r3/win/alloc-win.cpp b/src/VBox/Runtime/r3/win/alloc-win.cpp
new file mode 100644
index 00000000..a9ebe7f0
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/alloc-win.cpp
@@ -0,0 +1,210 @@
+/* $Id: alloc-win.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#ifdef IPRT_NO_CRT
+# define USE_VIRTUAL_ALLOC
+#endif
+#define LOG_GROUP RTLOGGROUP_MEM
+#include <iprt/win/windows.h>
+
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include <iprt/errcore.h>
+
+#ifndef USE_VIRTUAL_ALLOC
+# include <malloc.h>
+#endif
+
+
+RTDECL(void *) RTMemPageAllocTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    RT_NOREF_PV(pszTag);
+
+#ifdef USE_VIRTUAL_ALLOC
+    void *pv = VirtualAlloc(NULL, RT_ALIGN_Z(cb, PAGE_SIZE), MEM_COMMIT, PAGE_READWRITE);
+#else
+    void *pv = _aligned_malloc(RT_ALIGN_Z(cb, PAGE_SIZE), PAGE_SIZE);
+#endif
+    AssertMsg(pv, ("cb=%d lasterr=%d\n", cb, GetLastError()));
+    return pv;
+}
+
+
+RTDECL(void *) RTMemPageAllocExTag(size_t cb, uint32_t fFlags, const char *pszTag) RT_NO_THROW_DEF
+{
+    size_t const cbAligned = RT_ALIGN_Z(cb, PAGE_SIZE);
+    RT_NOREF_PV(pszTag);
+    AssertReturn(!(fFlags & ~RTMEMPAGEALLOC_F_VALID_MASK), NULL);
+
+#ifdef USE_VIRTUAL_ALLOC
+    void *pv = VirtualAlloc(NULL, cbAligned, MEM_COMMIT, PAGE_READWRITE);
+#else
+    void *pv = _aligned_malloc(cbAligned, PAGE_SIZE);
+#endif
+    AssertMsgReturn(pv, ("cb=%d lasterr=%d\n", cb, GetLastError()), NULL);
+
+    if (fFlags & RTMEMPAGEALLOC_F_ADVISE_LOCKED)
+    {
+        /** @todo check why we get ERROR_WORKING_SET_QUOTA here. */
+        BOOL const fOkay = VirtualLock(pv, cbAligned);
+        AssertMsg(fOkay || GetLastError() == ERROR_WORKING_SET_QUOTA, ("pv=%p cb=%d lasterr=%d\n", pv, cb, GetLastError()));
+        NOREF(fOkay);
+    }
+
+    if (fFlags & RTMEMPAGEALLOC_F_ZERO)
+        RT_BZERO(pv, cbAligned);
+
+    return pv;
+}
+
+
+RTDECL(void *) RTMemPageAllocZTag(size_t cb, const char *pszTag) RT_NO_THROW_DEF
+{
+    RT_NOREF_PV(pszTag);
+
+#ifdef USE_VIRTUAL_ALLOC
+    void *pv = VirtualAlloc(NULL, RT_ALIGN_Z(cb, PAGE_SIZE), MEM_COMMIT, PAGE_READWRITE);
+#else
+    void *pv = _aligned_malloc(RT_ALIGN_Z(cb, PAGE_SIZE), PAGE_SIZE);
+#endif
+    if (pv)
+    {
+        memset(pv, 0, RT_ALIGN_Z(cb, PAGE_SIZE));
+        return pv;
+    }
+    AssertMsgFailed(("cb=%d lasterr=%d\n", cb, GetLastError()));
+    return NULL;
+}
+
+
+RTDECL(void) RTMemPageFree(void *pv, size_t cb) RT_NO_THROW_DEF
+{
+    RT_NOREF_PV(cb);
+
+    if (pv)
+    {
+#ifdef USE_VIRTUAL_ALLOC
+        if (!VirtualFree(pv, 0, MEM_RELEASE))
+            AssertMsgFailed(("pv=%p lasterr=%d\n", pv, GetLastError()));
+#else
+        _aligned_free(pv);
+#endif
+    }
+}
+
+
+RTDECL(int) RTMemProtect(void *pv, size_t cb, unsigned fProtect) RT_NO_THROW_DEF
+{
+    /*
+     * Validate input.
+     */
+    if (cb == 0)
+    {
+        AssertMsgFailed(("!cb\n"));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (fProtect & ~(RTMEM_PROT_NONE | RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC))
+    {
+        AssertMsgFailed(("fProtect=%#x\n", fProtect));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Convert the flags.
+     */
+    int fProt;
+    Assert(!RTMEM_PROT_NONE);
+    switch (fProtect & (RTMEM_PROT_NONE | RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC))
+    {
+        case RTMEM_PROT_NONE:
+            fProt = PAGE_NOACCESS;
+            break;
+
+        case RTMEM_PROT_READ:
+            fProt = PAGE_READONLY;
+            break;
+
+        case RTMEM_PROT_READ | RTMEM_PROT_WRITE:
+            fProt = PAGE_READWRITE;
+            break;
+
+        case RTMEM_PROT_READ | RTMEM_PROT_WRITE | RTMEM_PROT_EXEC:
+            fProt = PAGE_EXECUTE_READWRITE;
+            break;
+
+        case RTMEM_PROT_READ | RTMEM_PROT_EXEC:
+            fProt = PAGE_EXECUTE_READWRITE;
+            break;
+
+        case RTMEM_PROT_WRITE:
+            fProt = PAGE_READWRITE;
+            break;
+
+        case RTMEM_PROT_WRITE | RTMEM_PROT_EXEC:
+            fProt = PAGE_EXECUTE_READWRITE;
+            break;
+
+        case RTMEM_PROT_EXEC:
+            fProt = PAGE_EXECUTE_READWRITE;
+            break;
+
+        /* If the compiler had any brains it would warn about this case. */
+        default:
+            AssertMsgFailed(("fProtect=%#x\n", fProtect));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    /*
+     * Align the request.
+     */
+    cb += (uintptr_t)pv & PAGE_OFFSET_MASK;
+    pv = (void *)((uintptr_t)pv & ~(uintptr_t)PAGE_OFFSET_MASK);
+
+    /*
+     * Change the page attributes.
+     */
+    DWORD fFlags = 0;
+    if (VirtualProtect(pv, cb, fProt, &fFlags))
+        return VINF_SUCCESS;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
diff --git a/src/VBox/Runtime/r3/win/allocex-win.cpp b/src/VBox/Runtime/r3/win/allocex-win.cpp
new file mode 100644
index 00000000..dca6d053
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/allocex-win.cpp
@@ -0,0 +1,133 @@
+/* $Id: allocex-win.cpp $ */
+/** @file
+ * IPRT - Memory Allocation, Extended Alloc Workers, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RTMEM_NO_WRAP_TO_EF_APIS
+#include <iprt/mem.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include <iprt/param.h>
+#include "../allocex.h"
+
+#include <iprt/win/windows.h>
+
+
+static int rtMemAllocExInRange(size_t cbAlloc, uint32_t fFlags, void **ppv, uintptr_t uAddr, uintptr_t uAddrLast)
+{
+    /*
+     * Try with every possible address hint since the possible range is very limited.
+     */
+    DWORD     fPageProt = (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE);
+    while (uAddr <= uAddrLast)
+    {
+        MEMORY_BASIC_INFORMATION MemInfo;
+        SIZE_T cbRange = VirtualQuery((void *)uAddr, &MemInfo, sizeof(MemInfo));
+        AssertReturn(cbRange == sizeof(MemInfo), VERR_NOT_SUPPORTED);
+        Assert(MemInfo.RegionSize > 0);
+
+        if (   MemInfo.State == MEM_FREE
+            && MemInfo.RegionSize >= cbAlloc)
+        {
+            void *pv = VirtualAlloc((void *)uAddr, cbAlloc, MEM_RESERVE | MEM_COMMIT, fPageProt);
+            if ((uintptr_t)pv == uAddr)
+            {
+                *ppv = pv;
+                return VINF_SUCCESS;
+            }
+            AssertStmt(!pv, VirtualFree(pv, cbAlloc, MEM_RELEASE));
+        }
+
+        /* skip ahead */
+        uintptr_t uAddrNext = (uintptr_t)MemInfo.BaseAddress + MemInfo.RegionSize;
+        if (uAddrNext <= uAddr)
+            break;
+        uAddr += uAddrNext;
+    }
+
+    return VERR_NO_MEMORY;
+}
+
+
+DECLHIDDEN(int) rtMemAllocEx16BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    cbAlloc = RT_ALIGN_Z(cbAlloc, PAGE_SIZE);
+    AssertReturn(cbAlloc <= _64K - PAGE_SIZE, VERR_NO_MEMORY);
+
+    /* Seems this doesn't work on W7/64... */
+    return rtMemAllocExInRange(cbAlloc, fFlags, ppv, PAGE_SIZE, _64K - cbAlloc);
+}
+
+
+DECLHIDDEN(int) rtMemAllocEx32BitReach(size_t cbAlloc, uint32_t fFlags, void **ppv)
+{
+    cbAlloc = RT_ALIGN_Z(cbAlloc, PAGE_SIZE);
+    AssertReturn(cbAlloc <= _2G+_1G, VERR_NO_MEMORY);
+
+    /*
+     * Just try first.
+     */
+    DWORD     fPageProt = (fFlags & RTMEMALLOCEX_FLAGS_EXEC ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE);
+    void *pv = VirtualAlloc(NULL, cbAlloc, MEM_RESERVE | MEM_COMMIT, fPageProt);
+    if (!pv)
+        return VERR_NO_MEMORY;
+    if ((uintptr_t)pv + cbAlloc - 1 < _4G)
+    {
+        *ppv = pv;
+        return VINF_SUCCESS;
+    }
+    VirtualFree(pv, cbAlloc, MEM_RELEASE);
+
+    /*
+     * No luck, do address scan based allocation.
+     */
+    return rtMemAllocExInRange(cbAlloc, fFlags, ppv, _64K, _4G - cbAlloc);
+}
+
+
+DECLHIDDEN(void) rtMemFreeExYyBitReach(void *pv, size_t cb, uint32_t fFlags)
+{
+    RT_NOREF_PV(fFlags);
+
+    BOOL fRc = VirtualFree(pv, cb, MEM_RELEASE);
+    Assert(fRc); RT_NOREF_PV(fRc);
+}
+
diff --git a/src/VBox/Runtime/r3/win/dir-win.cpp b/src/VBox/Runtime/r3/win/dir-win.cpp
new file mode 100644
index 00000000..f0a193ff
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/dir-win.cpp
@@ -0,0 +1,169 @@
+/* $Id: dir-win.cpp $ */
+/** @file
+ * IPRT - Directory, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/win/windows.h>
+
+#include <iprt/dir.h>
+#include <iprt/path.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include "internal/fs.h"
+#include "internal/path.h"
+
+
+
+RTDECL(int) RTDirCreate(const char *pszPath, RTFMODE fMode, uint32_t fCreate)
+{
+    /*
+     * Validate the file mode.
+     */
+    int rc;
+    fMode = rtFsModeNormalize(fMode, pszPath, 0, RTFS_TYPE_DIRECTORY);
+    if (rtFsModeIsValidPermissions(fMode))
+    {
+        /*
+         * Convert to UTF-16.
+         */
+        PRTUTF16 pwszString;
+        rc = RTPathWinFromUtf8(&pwszString, pszPath, 0 /*fFlags*/);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Create the directory.
+             */
+            if (CreateDirectoryW((LPCWSTR)pwszString, NULL))
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            /*
+             * Turn off indexing of directory through Windows Indexing Service
+             */
+            /** @todo This FILE_ATTRIBUTE_NOT_CONTENT_INDEXED hack (for .VDI files,
+             *        really) may cause failures on samba shares.  That really sweet and
+             *        need to be addressed differently.  We shouldn't be doing this
+             *        unless the caller actually asks for it, must less returning failure,
+             *        for crying out loud!  This is only important a couple of places in
+             *        main, if important is the right way to put it... */
+            if (   RT_SUCCESS(rc)
+                && !(fCreate & RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_DONT_SET))
+            {
+                if (   SetFileAttributesW((LPCWSTR)pwszString, FILE_ATTRIBUTE_NOT_CONTENT_INDEXED)
+                    || (fCreate & RTDIRCREATE_FLAGS_NOT_CONTENT_INDEXED_NOT_CRITICAL) )
+                    rc = VINF_SUCCESS;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+
+            RTPathWinFree(pwszString);
+        }
+    }
+    else
+    {
+        AssertMsgFailed(("Invalid file mode! %RTfmode\n", fMode));
+        rc = VERR_INVALID_FMODE;
+    }
+
+    LogFlow(("RTDirCreate(%p:{%s}, %RTfmode): returns %Rrc\n", pszPath, pszPath, fMode, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTDirRemove(const char *pszPath)
+{
+    /*
+     * Convert to UTF-16.
+     */
+    PRTUTF16 pwszString;
+    int rc = RTPathWinFromUtf8(&pwszString, pszPath, 0 /*fFlags*/);
+    AssertRC(rc);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Remove the directory.
+         */
+        if (RemoveDirectoryW((LPCWSTR)pwszString))
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        RTPathWinFree(pwszString);
+    }
+
+    LogFlow(("RTDirRemove(%p:{%s}): returns %Rrc\n", pszPath, pszPath, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTDirFlush(const char *pszPath)
+{
+    RT_NOREF_PV(pszPath);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTDirRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(*pszSrc, ("%p\n", pszSrc), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(*pszDst, ("%p\n", pszDst), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Call the worker.
+     */
+    int rc = rtPathWin32MoveRename(pszSrc, pszDst,
+                                   fRename & RTPATHRENAME_FLAGS_REPLACE ? MOVEFILE_REPLACE_EXISTING : 0,
+                                   RTFS_TYPE_DIRECTORY);
+
+    LogFlow(("RTDirRename(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n", pszSrc, pszSrc, pszDst, pszDst, fRename, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/direnum-win.cpp b/src/VBox/Runtime/r3/win/direnum-win.cpp
new file mode 100644
index 00000000..80d36864
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/direnum-win.cpp
@@ -0,0 +1,404 @@
+/* $Id: direnum-win.cpp $ */
+/** @file
+ * IPRT - Directory Enumeration, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#include <iprt/win/windows.h>
+
+#include <iprt/dir.h>
+#include <iprt/path.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include "internal/fs.h"
+#include "internal/dir.h"
+
+
+size_t rtDirNativeGetStructSize(const char *pszPath)
+{
+    NOREF(pszPath);
+    return sizeof(RTDIRINTERNAL);
+}
+
+
+int rtDirNativeOpen(PRTDIRINTERNAL pDir, uintptr_t hRelativeDir, void *pvNativeRelative))
+{
+    RT_NOREF(hRelativeDir, pvNativeRelative);
+
+    /*
+     * Setup the search expression.
+     *
+     * pszPathBuf is pointing to the return 4K return buffer for the RTPathReal()
+     * call in rtDirOpenCommon(), so all we gota do is check that we don't overflow
+     * it when adding the wildcard expression.
+     */
+/** @todo the pszPathBuf argument was removed in order to support paths longer than RTPATH_MAX.  Rewrite this code. */
+    size_t cbExpr;
+    const char *pszExpr;
+    if (pDir->enmFilter == RTDIRFILTER_WINNT)
+    {
+        pszExpr = pDir->pszFilter;
+        cbExpr  = pDir->cchFilter + 1;
+    }
+    else
+    {
+        pszExpr = "*";
+        cbExpr  = sizeof("*");
+    }
+    if (pDir->cchPath + cbExpr > RTPATH_MAX)
+        return VERR_FILENAME_TOO_LONG;
+    memcpy(pszPathBuf + pDir->cchPath, pszExpr, cbExpr);
+
+
+    /*
+     * Attempt opening the search.
+     */
+    PRTUTF16 pwszName;
+    int rc = RTPathWinFromUtf8(pwszPathBuf, &pwszName, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        pDir->hDir = FindFirstFileW((LPCWSTR)pwszName, &pDir->Data);
+        if (pDir->hDir != INVALID_HANDLE_VALUE)
+            pDir->fDataUnread = true;
+        else
+        {
+            DWORD dwErr = GetLastError();
+            /* Theoretical case of an empty directory or more normal case of no matches. */
+            if (   dwErr == ERROR_FILE_NOT_FOUND
+                || dwErr == ERROR_NO_MORE_FILES /* ???*/)
+                pDir->fDataUnread = false;
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        RTPathWinFree(pwszName);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTDirClose(PRTDIRINTERNAL pDir)
+{
+    /*
+     * Validate input.
+     */
+    if (!pDir)
+        return VERR_INVALID_PARAMETER;
+    if (pDir->u32Magic != RTDIR_MAGIC)
+    {
+        AssertMsgFailed(("Invalid pDir=%p\n", pDir));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Close the handle.
+     */
+    pDir->u32Magic++;
+    if (pDir->hDir != INVALID_HANDLE_VALUE)
+    {
+        BOOL fRc = FindClose(pDir->hDir);
+        Assert(fRc);
+        pDir->hDir = INVALID_HANDLE_VALUE;
+    }
+    RTStrFree(pDir->pszName);
+    pDir->pszName = NULL;
+    RTMemFree(pDir);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTDirRead(RTDIR hDir, PRTDIRENTRY pDirEntry, size_t *pcbDirEntry)
+{
+    PPRTDIRINTERNAL pDir = hDir;
+
+    /*
+     * Validate input.
+     */
+    if (!pDir || pDir->u32Magic != RTDIR_MAGIC)
+    {
+        AssertMsgFailed(("Invalid pDir=%p\n", pDir));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (!pDirEntry)
+    {
+        AssertMsgFailed(("Invalid pDirEntry=%p\n", pDirEntry));
+        return VERR_INVALID_PARAMETER;
+    }
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        cbDirEntry = *pcbDirEntry;
+        if (cbDirEntry < RT_UOFFSETOF(RTDIRENTRY, szName[2]))
+        {
+            AssertMsgFailed(("Invalid *pcbDirEntry=%zu (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRY, szName[2])));
+            return VERR_INVALID_PARAMETER;
+        }
+    }
+
+    /*
+     * Fetch data?
+     */
+    if (!pDir->fDataUnread)
+    {
+        RTStrFree(pDir->pszName);
+        pDir->pszName = NULL;
+
+        BOOL fRc = FindNextFileW(pDir->hDir, &pDir->Data);
+        if (!fRc)
+        {
+            int iErr = GetLastError();
+            if (pDir->hDir == INVALID_HANDLE_VALUE || iErr == ERROR_NO_MORE_FILES)
+                return VERR_NO_MORE_FILES;
+            return RTErrConvertFromWin32(iErr);
+        }
+    }
+
+    /*
+     * Convert the filename to UTF-8.
+     */
+    if (!pDir->pszName)
+    {
+        int rc = RTUtf16ToUtf8((PCRTUTF16)pDir->Data.cFileName, &pDir->pszName);
+        if (RT_FAILURE(rc))
+        {
+            pDir->pszName = NULL;
+            return rc;
+        }
+        pDir->cchName = strlen(pDir->pszName);
+    }
+
+    /*
+     * Check if we've got enough space to return the data.
+     */
+    const char  *pszName    = pDir->pszName;
+    const size_t cchName    = pDir->cchName;
+    const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRY, szName[1]) + cchName;
+    if (pcbDirEntry)
+        *pcbDirEntry = cbRequired;
+    if (cbRequired > cbDirEntry)
+        return VERR_BUFFER_OVERFLOW;
+
+    /*
+     * Setup the returned data.
+     */
+    pDir->fDataUnread  = false;
+    pDirEntry->INodeId = 0; /** @todo we can use the fileid here if we must (see GetFileInformationByHandle). */
+    pDirEntry->enmType = pDir->Data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY
+                       ? RTDIRENTRYTYPE_DIRECTORY : RTDIRENTRYTYPE_FILE;
+    pDirEntry->cbName  = (uint16_t)cchName;
+    Assert(pDirEntry->cbName == cchName);
+    memcpy(pDirEntry->szName, pszName, cchName + 1);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTDirReadEx(RTDIR hDir, PRTDIRENTRYEX pDirEntry, size_t *pcbDirEntry, RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    PPRTDIRINTERNAL pDir = hDir;
+    /** @todo Symlinks: Find[First|Next]FileW will return info about
+        the link, so RTPATH_F_FOLLOW_LINK is not handled correctly. */
+    /*
+     * Validate input.
+     */
+    if (!pDir || pDir->u32Magic != RTDIR_MAGIC)
+    {
+        AssertMsgFailed(("Invalid pDir=%p\n", pDir));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (!pDirEntry)
+    {
+        AssertMsgFailed(("Invalid pDirEntry=%p\n", pDirEntry));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (    enmAdditionalAttribs < RTFSOBJATTRADD_NOTHING
+        ||  enmAdditionalAttribs > RTFSOBJATTRADD_LAST)
+    {
+        AssertMsgFailed(("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs));
+        return VERR_INVALID_PARAMETER;
+    }
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+    size_t cbDirEntry = sizeof(*pDirEntry);
+    if (pcbDirEntry)
+    {
+        cbDirEntry = *pcbDirEntry;
+        if (cbDirEntry < RT_UOFFSETOF(RTDIRENTRYEX, szName[2]))
+        {
+            AssertMsgFailed(("Invalid *pcbDirEntry=%zu (min %zu)\n", *pcbDirEntry, RT_UOFFSETOF(RTDIRENTRYEX, szName[2])));
+            return VERR_INVALID_PARAMETER;
+        }
+    }
+
+    /*
+     * Fetch data?
+     */
+    if (!pDir->fDataUnread)
+    {
+        RTStrFree(pDir->pszName);
+        pDir->pszName = NULL;
+
+        BOOL fRc = FindNextFileW(pDir->hDir, &pDir->Data);
+        if (!fRc)
+        {
+            int iErr = GetLastError();
+            if (pDir->hDir == INVALID_HANDLE_VALUE || iErr == ERROR_NO_MORE_FILES)
+                return VERR_NO_MORE_FILES;
+            return RTErrConvertFromWin32(iErr);
+        }
+    }
+
+    /*
+     * Convert the filename to UTF-8.
+     */
+    if (!pDir->pszName)
+    {
+        int rc = RTUtf16ToUtf8((PCRTUTF16)pDir->Data.cFileName, &pDir->pszName);
+        if (RT_FAILURE(rc))
+        {
+            pDir->pszName = NULL;
+            return rc;
+        }
+        pDir->cchName = strlen(pDir->pszName);
+    }
+
+    /*
+     * Check if we've got enough space to return the data.
+     */
+    const char  *pszName    = pDir->pszName;
+    const size_t cchName    = pDir->cchName;
+    const size_t cbRequired = RT_UOFFSETOF(RTDIRENTRYEX, szName[1]) + cchName;
+    if (pcbDirEntry)
+        *pcbDirEntry = cbRequired;
+    if (cbRequired > cbDirEntry)
+        return VERR_BUFFER_OVERFLOW;
+
+    /*
+     * Setup the returned data.
+     */
+    pDir->fDataUnread  = false;
+    pDirEntry->cbName  = (uint16_t)cchName;
+    Assert(pDirEntry->cbName == cchName);
+    memcpy(pDirEntry->szName, pszName, cchName + 1);
+    if (pDir->Data.cAlternateFileName[0])
+    {
+        /* copy and calc length */
+        PCRTUTF16 pwszSrc = (PCRTUTF16)pDir->Data.cAlternateFileName;
+        PRTUTF16  pwszDst = pDirEntry->wszShortName;
+        uint32_t  off = 0;
+        while (off < RT_ELEMENTS(pDirEntry->wszShortName) - 1U && pwszSrc[off])
+        {
+            pwszDst[off] = pwszSrc[off];
+            off++;
+        }
+        pDirEntry->cwcShortName = (uint16_t)off;
+
+        /* zero the rest */
+        do
+            pwszDst[off++] = '\0';
+        while (off < RT_ELEMENTS(pDirEntry->wszShortName));
+    }
+    else
+    {
+        memset(pDirEntry->wszShortName, 0, sizeof(pDirEntry->wszShortName));
+        pDirEntry->cwcShortName = 0;
+    }
+
+    pDirEntry->Info.cbObject    = ((uint64_t)pDir->Data.nFileSizeHigh << 32)
+                                |  (uint64_t)pDir->Data.nFileSizeLow;
+    pDirEntry->Info.cbAllocated = pDirEntry->Info.cbObject;
+
+    Assert(sizeof(uint64_t) == sizeof(pDir->Data.ftCreationTime));
+    RTTimeSpecSetNtTime(&pDirEntry->Info.BirthTime,         *(uint64_t *)&pDir->Data.ftCreationTime);
+    RTTimeSpecSetNtTime(&pDirEntry->Info.AccessTime,        *(uint64_t *)&pDir->Data.ftLastAccessTime);
+    RTTimeSpecSetNtTime(&pDirEntry->Info.ModificationTime,  *(uint64_t *)&pDir->Data.ftLastWriteTime);
+    pDirEntry->Info.ChangeTime  = pDirEntry->Info.ModificationTime;
+
+    pDirEntry->Info.Attr.fMode  = rtFsModeFromDos((pDir->Data.dwFileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT,
+                                                   pszName, cchName, pDir->Data.dwReserved0, 0);
+
+    /*
+     * Requested attributes (we cannot provide anything actually).
+     */
+    switch (enmAdditionalAttribs)
+    {
+        case RTFSOBJATTRADD_EASIZE:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+            pDirEntry->Info.Attr.u.EASize.cb            = 0;
+            break;
+
+        case RTFSOBJATTRADD_UNIX:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+            pDirEntry->Info.Attr.u.Unix.uid             = ~0U;
+            pDirEntry->Info.Attr.u.Unix.gid             = ~0U;
+            pDirEntry->Info.Attr.u.Unix.cHardlinks      = 1;
+            pDirEntry->Info.Attr.u.Unix.INodeIdDevice   = 0; /** @todo Use the volume serial number (see GetFileInformationByHandle). */
+            pDirEntry->Info.Attr.u.Unix.INodeId         = 0; /** @todo Use the fileid (see GetFileInformationByHandle). */
+            pDirEntry->Info.Attr.u.Unix.fFlags          = 0;
+            pDirEntry->Info.Attr.u.Unix.GenerationId    = 0;
+            pDirEntry->Info.Attr.u.Unix.Device          = 0;
+            break;
+
+        case RTFSOBJATTRADD_NOTHING:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_NOTHING;
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+            pDirEntry->Info.Attr.u.UnixOwner.uid        = ~0U;
+            pDirEntry->Info.Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            pDirEntry->Info.Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+            pDirEntry->Info.Attr.u.UnixGroup.gid        = ~0U;
+            pDirEntry->Info.Attr.u.UnixGroup.szName[0]  = '\0';
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    return VINF_SUCCESS;
+}
+
diff --git a/src/VBox/Runtime/r3/win/dllmain-win.cpp b/src/VBox/Runtime/r3/win/dllmain-win.cpp
new file mode 100644
index 00000000..b52d059b
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/dllmain-win.cpp
@@ -0,0 +1,100 @@
+/* $Id: dllmain-win.cpp $ */
+/** @file
+ * IPRT - Win32 DllMain (Ring-3).
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/windows.h>
+#include <iprt/thread.h>
+#include <iprt/param.h>
+#include "internal/thread.h"
+
+
+
+/**
+ * Increases the load count on the IPRT DLL so it won't unload.
+ *
+ * This is a separate function so as to not overflow the stack of threads with
+ * very little of it.
+ *
+ * @param   hModule     The IPRT DLL module handle.
+ */
+DECL_NO_INLINE(static, void) EnsureNoUnload(HMODULE hModule)
+{
+    WCHAR wszName[RTPATH_MAX];
+    SetLastError(NO_ERROR);
+    if (   GetModuleFileNameW(hModule, wszName, RT_ELEMENTS(wszName)) > 0
+        && GetLastError() == NO_ERROR)
+    {
+        int cExtraLoads = 32;
+        while (cExtraLoads-- > 0)
+            LoadLibraryW(wszName);
+    }
+}
+
+
+/**
+ * The Dll main entry point.
+ */
+BOOL __stdcall DllMain(HANDLE hModule, DWORD dwReason, PVOID pvReserved)
+{
+    RT_NOREF_PV(pvReserved);
+
+    switch (dwReason)
+    {
+        /*
+         * When attaching to a process, we'd like to make sure IPRT stays put
+         * and doesn't get unloaded.
+         */
+        case DLL_PROCESS_ATTACH:
+            EnsureNoUnload((HMODULE)hModule);
+            break;
+
+        case DLL_PROCESS_DETACH:
+        case DLL_THREAD_ATTACH:
+        default:
+            /* ignore */
+            break;
+
+        case DLL_THREAD_DETACH:
+            rtThreadWinTlsDestruction();
+            rtThreadNativeDetach();
+            break;
+    }
+    return TRUE;
+}
+
diff --git a/src/VBox/Runtime/r3/win/env-win.cpp b/src/VBox/Runtime/r3/win/env-win.cpp
new file mode 100644
index 00000000..89577098
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/env-win.cpp
@@ -0,0 +1,520 @@
+/* $Id: env-win.cpp $ */
+/** @file
+ * IPRT - Environment, Posix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/env.h>
+
+#ifdef IPRT_NO_CRT
+# include <iprt/asm.h>
+#endif
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/string.h>
+#include <iprt/mem.h>
+#include <iprt/utf16.h>
+
+#ifndef IPRT_NO_CRT
+# include <stdlib.h>
+# include <errno.h>
+#endif
+#include <iprt/win/windows.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#ifdef IPRT_NO_CRT
+static uint32_t volatile g_idxGetEnvBufs = 0;
+static char             *g_apszGetEnvBufs[64]; /* leak */
+#endif
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+int rtEnvSetUtf8Worker(const char *pchVar, size_t cchVar, const char *pszValue);
+
+
+#if defined(RT_ARCH_X86) && defined(RT_OS_WINDOWS)
+/**
+ * This is a workaround for NT 3.x not setting the last error.
+ */
+static DWORD rtEnvNt31CheckEmpty(PCRTUTF16 pwszVar)
+{
+    /* Check the version first: */
+    DWORD dwVersion = GetVersion();
+    if (RT_BYTE1(dwVersion) != 3)
+        return 0;
+
+    /* When called with an empty buffer, we should get 1 if empty value
+       and 0 if not found:  */
+    DWORD cwcNeeded = GetEnvironmentVariableW(pwszVar, NULL, 0);
+    return cwcNeeded == 0 ? ERROR_ENVVAR_NOT_FOUND : NO_ERROR;
+}
+#endif
+
+
+RTDECL(bool) RTEnvExistsBad(const char *pszVar)
+{
+#ifndef IPRT_NO_CRT
+    return RTEnvGetBad(pszVar) != NULL;
+#else
+    return RTEnvExistsUtf8(pszVar);
+#endif
+}
+
+
+RTDECL(bool) RTEnvExist(const char *pszVar)
+{
+#ifndef IPRT_NO_CRT
+    return RTEnvExistsBad(pszVar);
+#else
+    return RTEnvExistsUtf8(pszVar);
+#endif
+}
+
+
+RTDECL(bool) RTEnvExistsUtf8(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, false);
+
+    PRTUTF16 pwszVar;
+    int rc = RTStrToUtf16(pszVar, &pwszVar);
+    AssertRCReturn(rc, false);
+
+#ifndef IPRT_NO_CRT
+    bool fRet = _wgetenv(pwszVar) != NULL;
+#else
+    DWORD dwRet = GetEnvironmentVariableW(pwszVar, NULL, 0);
+    bool fRet = dwRet != 0;
+#endif
+
+    RTUtf16Free(pwszVar);
+    return fRet;
+}
+
+
+RTDECL(const char *) RTEnvGetBad(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, NULL);
+#ifndef IPRT_NO_CRT
+    return getenv(pszVar);
+#else
+    /*
+     * Query the value into heap buffer which we give a lifetime of 64
+     * RTEnvGetBad calls.
+     */
+    char *pszValue = RTEnvDup(pszVar);
+    if (pszValue)
+    {
+        RTMEM_MAY_LEAK(pszValue); /* Quite possible we'll leak this, but the leak is limited to 64 values. */
+
+        uint32_t idx = ASMAtomicIncU32(&g_idxGetEnvBufs) % RT_ELEMENTS(g_apszGetEnvBufs);
+        char *pszOld = (char *)ASMAtomicXchgPtr((void * volatile *)&g_apszGetEnvBufs[idx], pszValue);
+        RTStrFree(pszOld);
+    }
+    return pszValue;
+#endif
+}
+
+
+RTDECL(const char *) RTEnvGet(const char *pszVar)
+{
+    return RTEnvGetBad(pszVar);
+}
+
+RTDECL(int) RTEnvGetUtf8(const char *pszVar, char *pszValue, size_t cbValue, size_t *pcchActual)
+{
+    AssertPtrReturn(pszVar, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pszValue, VERR_INVALID_POINTER);
+    AssertReturn(pszValue || !cbValue, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pcchActual, VERR_INVALID_POINTER);
+    AssertReturn(pcchActual || (pszValue && cbValue), VERR_INVALID_PARAMETER);
+    AssertReturn(strchr(pszVar, '=') == NULL, VERR_ENV_INVALID_VAR_NAME);
+
+    if (pcchActual)
+        *pcchActual = 0;
+
+    /*
+     * Convert the name to UTF-16.
+     */
+    PRTUTF16 pwszVar;
+    int rc = RTStrToUtf16(pszVar, &pwszVar);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Query the variable.  First try with a medium sized stack buffer (too
+     * small for your typical PATH, but large enough for most other things).
+     */
+    RTUTF16  wszValue[512];
+    uint32_t cwcValueBuf   = RT_ELEMENTS(wszValue);
+    PRTUTF16 pwszValue     = wszValue;
+    PRTUTF16 pwszValueFree = NULL;
+
+    for (unsigned iTry = 0;; iTry++)
+    {
+        /* This API is weird, it didn't always set ERROR_BUFFER_OVERFLOW nor ERROR_ENVVAR_NOT_FOUND.
+           Note! Assume that the CRT transparently updates the process
+                 environment and that we don't need to use _wgetenv_s here. */
+        SetLastError(NO_ERROR);
+        DWORD const cwcValueRet = GetEnvironmentVariableW(pwszVar, pwszValue, cwcValueBuf);
+        DWORD       dwErr       = GetLastError();
+
+        if (cwcValueRet < cwcValueBuf)
+        {
+#ifdef RT_ARCH_X86
+            if (cwcValueRet == 0 && dwErr == NO_ERROR)
+                dwErr = rtEnvNt31CheckEmpty(pwszVar);
+#endif
+            if (cwcValueRet > 0 || dwErr == NO_ERROR) /* In case of empty values we have to see if last error was set or not. */
+            {
+                if (cbValue)
+                    rc = RTUtf16ToUtf8Ex(pwszValue, cwcValueRet, &pszValue, cbValue, pcchActual);
+                else
+                    rc = RTUtf16CalcUtf8LenEx(pwszValue, cwcValueRet, pcchActual);
+            }
+            else
+            {
+                Assert(cwcValueRet == 0);
+                Assert(dwErr != NO_ERROR);
+                rc = RTErrConvertFromWin32(dwErr);
+            }
+            break;
+        }
+
+        /*
+         * Insufficient buffer, so increase it.  The first re-try will use the
+         * returned size, further re-tries will max out with a multiple of the
+         * stack buffer till we reaches 32KB chars (128 loops).
+         */
+        Assert(dwErr == NO_ERROR || dwErr == ERROR_BUFFER_OVERFLOW);
+        RTMemTmpFree(pwszValueFree);
+        AssertBreakStmt(cwcValueBuf < _32K, rc = VERR_INTERNAL_ERROR_3 /* not a good one */);
+
+        cwcValueBuf = RT_MAX(cwcValueRet + iTry, RT_ELEMENTS(wszValue) * iTry);
+        pwszValueFree = pwszValue = (PRTUTF16)RTMemTmpAlloc(cwcValueBuf * sizeof(RTUTF16));
+        AssertBreakStmt(pwszValue, rc = VERR_NO_TMP_MEMORY);
+    }
+
+    RTMemTmpFree(pwszValueFree);
+    RTUtf16Free(pwszVar);
+    return rc;
+}
+
+
+RTDECL(char *) RTEnvDup(const char *pszVar)
+{
+    AssertPtrReturn(pszVar, NULL);
+
+    /*
+     * Convert the name to UTF-16.
+     */
+    PRTUTF16 pwszVar;
+    int rc = RTStrToUtf16(pszVar, &pwszVar);
+    AssertRCReturn(rc, NULL);
+
+    /*
+     * Query the variable.  First try with a medium sized stack buffer (too
+     * small for your typical PATH, but large enough for most other things).
+     */
+    char    *pszRet = NULL;
+    RTUTF16  wszValue[512];
+    uint32_t cwcValueBuf   = RT_ELEMENTS(wszValue);
+    PRTUTF16 pwszValue     = wszValue;
+    PRTUTF16 pwszValueFree = NULL;
+
+    for (unsigned iTry = 0;; iTry++)
+    {
+        /* This API is weird, it didn't always set ERROR_BUFFER_OVERFLOW nor ERROR_ENVVAR_NOT_FOUND.
+           Note! Assume that the CRT transparently updates the process
+                 environment and that we don't need to use _wgetenv_s here. */
+        SetLastError(NO_ERROR);
+        DWORD const cwcValueRet = GetEnvironmentVariableW(pwszVar, pwszValue, cwcValueBuf);
+        DWORD       dwErr       = GetLastError();
+
+        if (cwcValueRet < cwcValueBuf)
+        {
+#ifdef RT_ARCH_X86
+            if (cwcValueRet == 0 && dwErr == NO_ERROR)
+                dwErr = rtEnvNt31CheckEmpty(pwszVar);
+#endif
+            if (cwcValueRet > 0 || dwErr == NO_ERROR) /* In case of empty values we have to see if last error was set or not. */
+            {
+                rc = RTUtf16ToUtf8Ex(pwszValue, cwcValueRet, &pszRet, 0, NULL);
+                if (RT_FAILURE(rc))
+                    pszRet = NULL;
+            }
+            else
+            {
+                Assert(cwcValueRet == 0);
+                Assert(dwErr != NO_ERROR);
+            }
+            break;
+        }
+
+        /*
+         * Insufficient buffer, so increase it.  The first re-try will use the
+         * returned size, further re-tries will max out with a multiple of the
+         * stack buffer till we reaches 32KB chars (128 loops).
+         */
+        Assert(dwErr == NO_ERROR || dwErr == ERROR_BUFFER_OVERFLOW);
+        RTMemTmpFree(pwszValueFree);
+        AssertBreakStmt(cwcValueBuf < _32K, rc = VERR_INTERNAL_ERROR_3 /* not a good one */);
+
+        cwcValueBuf = RT_MAX(cwcValueRet + iTry, RT_ELEMENTS(wszValue) * iTry);
+        pwszValueFree = pwszValue = (PRTUTF16)RTMemTmpAlloc(cwcValueBuf * sizeof(RTUTF16));
+        AssertBreakStmt(pwszValue, rc = VERR_NO_TMP_MEMORY);
+    }
+
+    RTMemTmpFree(pwszValueFree);
+    RTUtf16Free(pwszVar);
+    return pszRet;
+}
+
+
+RTDECL(int) RTEnvPutBad(const char *pszVarEqualValue)
+{
+#ifndef IPRT_NO_CRT
+    /** @todo putenv is a source memory leaks. deal with this on a per system basis. */
+    if (!putenv((char *)pszVarEqualValue))
+        return 0;
+    return RTErrConvertFromErrno(errno);
+#else
+    return RTEnvPutUtf8(pszVarEqualValue);
+#endif
+}
+
+
+RTDECL(int) RTEnvPut(const char *pszVarEqualValue)
+{
+#ifndef IPRT_NO_CRT
+    return RTEnvPutBad(pszVarEqualValue);
+#else
+    return RTEnvPutUtf8(pszVarEqualValue);
+#endif
+}
+
+
+RTDECL(int) RTEnvPutUtf8(const char *pszVarEqualValue)
+{
+    PRTUTF16 pwszVarEqualValue;
+    int rc = RTStrToUtf16(pszVarEqualValue, &pwszVarEqualValue);
+    if (RT_SUCCESS(rc))
+    {
+#ifndef IPRT_NO_CRT
+        if (!_wputenv(pwszVarEqualValue))
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromErrno(errno);
+#else
+        PRTUTF16 pwszValue = RTUtf16Chr(pwszVarEqualValue, '=');
+        if (pwszValue)
+        {
+            *pwszValue++ = '\0';
+
+            SetLastError(*pwszValue ? ERROR_OUTOFMEMORY : ERROR_ENVVAR_NOT_FOUND); /* The API did not always set the last error. */
+            if (SetEnvironmentVariableW(pwszVarEqualValue, *pwszValue ? pwszValue : NULL))
+                rc = VINF_SUCCESS;
+            else
+            {
+                DWORD dwErr = GetLastError();
+                if (dwErr == ERROR_ENVVAR_NOT_FOUND)
+                {
+                    Assert(!*pwszValue);
+                    rc = VINF_SUCCESS;
+                }
+                else
+                {
+                    Assert(*pwszValue);
+                    rc = RTErrConvertFromWin32(GetLastError());
+                }
+            }
+        }
+        else
+            rc = VERR_INVALID_PARAMETER;
+#endif
+        RTUtf16Free(pwszVarEqualValue);
+    }
+    return rc;
+}
+
+
+
+RTDECL(int) RTEnvSetBad(const char *pszVar, const char *pszValue)
+{
+#ifndef IPRT_NO_CRT
+    AssertMsgReturn(strchr(pszVar, '=') == NULL, ("'%s'\n", pszVar), VERR_ENV_INVALID_VAR_NAME);
+    int rc;
+    if (!RTEnvExist(pszVar))
+        rc = VINF_ENV_VAR_NOT_FOUND;
+    else
+    {
+        errno_t rcErrno = _putenv_s(pszVar, *pszValue ? pszValue : " " /* wrong, but will be treated as unset otherwise */);
+        if (rcErrno == 0)
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromErrno(rcErrno);
+    }
+    return rc;
+#else
+    return RTEnvSetUtf8(pszVar, pszValue);
+#endif
+}
+
+
+RTDECL(int) RTEnvSet(const char *pszVar, const char *pszValue)
+{
+#ifndef IPRT_NO_CRT
+    return RTEnvSetBad(pszVar, pszValue);
+#else
+    return RTEnvSetUtf8(pszVar, pszValue);
+#endif
+}
+
+
+/**
+ * Worker common to RTEnvSetUtf8() and rtEnvSetExWorker().
+ */
+int rtEnvSetUtf8Worker(const char *pchVar, size_t cchVar, const char *pszValue)
+{
+    PRTUTF16 pwszVar;
+    int rc = RTStrToUtf16Ex(pchVar, cchVar, &pwszVar, 0, NULL);
+    if (RT_SUCCESS(rc))
+    {
+        PRTUTF16 pwszValue;
+        rc = RTStrToUtf16(pszValue, &pwszValue);
+        if (RT_SUCCESS(rc))
+        {
+#ifndef IPRT_NO_CRT
+            errno_t rcErrno = _wputenv_s(pwszVar,
+                                         *pwszValue ? pwszValue : L" " /* wrong, but will be treated as unset otherwise */);
+            if (rcErrno == 0)
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromErrno(rcErrno);
+#else
+            SetLastError(ERROR_OUTOFMEMORY); /* The API did not always set the last error. */
+            if (SetEnvironmentVariableW(pwszVar, pwszValue))
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+#endif
+            RTUtf16Free(pwszValue);
+        }
+        RTUtf16Free(pwszVar);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTEnvSetUtf8(const char *pszVar, const char *pszValue)
+{
+    size_t cchVar = strlen(pszVar);
+    AssertReturn(memchr(pszVar, '=', cchVar) == NULL, VERR_ENV_INVALID_VAR_NAME);
+    return rtEnvSetUtf8Worker(pszVar, cchVar, pszValue);
+}
+
+
+RTDECL(int) RTEnvUnsetBad(const char *pszVar)
+{
+#ifndef IPRT_NO_CRT
+    AssertReturn(strchr(pszVar, '=') == NULL, VERR_ENV_INVALID_VAR_NAME);
+    int rc;
+    if (!RTEnvExist(pszVar))
+        rc = VINF_ENV_VAR_NOT_FOUND;
+    else
+    {
+        errno_t rcErrno = _putenv_s(pszVar, NULL);
+        if (rcErrno == 0)
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromErrno(rcErrno);
+    }
+    return rc;
+#else
+    return RTEnvUnsetUtf8(pszVar);
+#endif
+}
+
+
+RTDECL(int) RTEnvUnset(const char *pszVar)
+{
+#ifndef IPRT_NO_CRT
+    return RTEnvUnsetBad(pszVar);
+#else
+    return RTEnvUnsetUtf8(pszVar);
+#endif
+}
+
+
+RTDECL(int) RTEnvUnsetUtf8(const char *pszVar)
+{
+    AssertReturn(strchr(pszVar, '=') == NULL, VERR_ENV_INVALID_VAR_NAME);
+
+    PRTUTF16 pwszVar;
+    int rc = RTStrToUtf16(pszVar, &pwszVar);
+    if (RT_SUCCESS(rc))
+    {
+#ifndef IPRT_NO_CRT
+        if (_wgetenv(pwszVar))
+        {
+            errno_t rcErrno = _wputenv_s(pwszVar, NULL);
+            if (rcErrno == 0)
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromErrno(rcErrno);
+        }
+        else
+            rc = VINF_ENV_VAR_NOT_FOUND;
+#else
+        SetLastError(ERROR_ENVVAR_NOT_FOUND); /* The API did not always set the last error. */
+        if (SetEnvironmentVariableW(pwszVar, NULL))
+            rc = VINF_SUCCESS;
+        else
+        {
+            DWORD dwErr = GetLastError();
+            rc = dwErr == ERROR_ENVVAR_NOT_FOUND ? VINF_ENV_VAR_NOT_FOUND : RTErrConvertFromWin32(dwErr);
+        }
+#endif
+        RTUtf16Free(pwszVar);
+    }
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/errvars-win.cpp b/src/VBox/Runtime/r3/win/errvars-win.cpp
new file mode 100644
index 00000000..6d8b4814
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/errvars-win.cpp
@@ -0,0 +1,108 @@
+/* $Id: errvars-win.cpp $ */
+/** @file
+ * IPRT - Save and Restore Error Variables, Windows Ring-3.
+ */
+
+/*
+ * Copyright (C) 2011-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/win/winsock2.h>
+#ifndef IPRT_NO_CRT
+# include <errno.h>
+#endif
+
+#include <iprt/errcore.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include "internal/magics.h"
+#include "internal-r3-win.h"
+
+
+
+RTDECL(PRTERRVARS) RTErrVarsSave(PRTERRVARS pVars)
+{
+    pVars->ai32Vars[0] = RTERRVARS_MAGIC;
+    pVars->ai32Vars[1] = GetLastError();
+    pVars->ai32Vars[2] = g_pfnWSAGetLastError ? g_pfnWSAGetLastError() : WSANOTINITIALISED;
+#ifndef IPRT_NO_CRT
+    pVars->ai32Vars[3] = errno;
+#endif
+    return pVars;
+}
+
+
+RTDECL(void) RTErrVarsRestore(PCRTERRVARS pVars)
+{
+    AssertReturnVoid(pVars->ai32Vars[0] == RTERRVARS_MAGIC);
+#ifndef IPRT_NO_CRT
+    errno = pVars->ai32Vars[3];
+#endif
+    if (   pVars->ai32Vars[2] != WSANOTINITIALISED
+        && g_pfnWSASetLastError)
+        g_pfnWSASetLastError(pVars->ai32Vars[2]);
+    SetLastError(pVars->ai32Vars[1]);
+}
+
+
+RTDECL(bool) RTErrVarsAreEqual(PCRTERRVARS pVars1, PCRTERRVARS pVars2)
+{
+    Assert(pVars1->ai32Vars[0] == RTERRVARS_MAGIC);
+    Assert(pVars2->ai32Vars[0] == RTERRVARS_MAGIC);
+
+    return pVars1->ai32Vars[0] == pVars2->ai32Vars[0]
+        && pVars1->ai32Vars[1] == pVars2->ai32Vars[1]
+        && pVars1->ai32Vars[2] == pVars2->ai32Vars[2]
+#ifndef IPRT_NO_CRT
+        && pVars1->ai32Vars[3] == pVars2->ai32Vars[3]
+#endif
+        ;
+}
+
+
+RTDECL(bool) RTErrVarsHaveChanged(PCRTERRVARS pVars)
+{
+    Assert(pVars->ai32Vars[0] == RTERRVARS_MAGIC);
+
+    return pVars->ai32Vars[0] != RTERRVARS_MAGIC
+        || (uint32_t)pVars->ai32Vars[1] != GetLastError()
+        || pVars->ai32Vars[2] != (g_pfnWSAGetLastError ? g_pfnWSAGetLastError() : WSANOTINITIALISED)
+#ifndef IPRT_NO_CRT
+        || pVars->ai32Vars[3] != errno
+#endif
+        ;
+
+}
+
diff --git a/src/VBox/Runtime/r3/win/fileaio-win.cpp b/src/VBox/Runtime/r3/win/fileaio-win.cpp
new file mode 100644
index 00000000..a3fb934d
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/fileaio-win.cpp
@@ -0,0 +1,554 @@
+/* $Id: fileaio-win.cpp $ */
+/** @file
+ * IPRT - File async I/O, native implementation for the Windows host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+
+#include <iprt/asm.h>
+#include <iprt/file.h>
+#include <iprt/mem.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include "internal/fileaio.h"
+
+#include <iprt/win/windows.h>
+
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Transfer direction.
+ */
+typedef enum TRANSFERDIRECTION
+{
+    TRANSFERDIRECTION_INVALID = 0,
+    /** Read. */
+    TRANSFERDIRECTION_READ,
+    /** Write. */
+    TRANSFERDIRECTION_WRITE,
+    /** The usual 32-bit hack. */
+    TRANSFERDIRECTION_32BIT_HACK = 0x7fffffff
+} TRANSFERDIRECTION;
+
+/**
+ * Async I/O completion context state.
+ */
+typedef struct RTFILEAIOCTXINTERNAL
+{
+    /** handle to I/O completion port. */
+    HANDLE            hIoCompletionPort;
+    /** Current number of requests pending. */
+    volatile int32_t  cRequests;
+    /** Flag whether the thread was woken up. */
+    volatile bool     fWokenUp;
+    /** Flag whether the thread is currently waiting. */
+    volatile bool     fWaiting;
+    /** Flags given during creation. */
+    uint32_t          fFlags;
+    /** Magic value (RTFILEAIOCTX_MAGIC). */
+    uint32_t          u32Magic;
+} RTFILEAIOCTXINTERNAL;
+/** Pointer to an internal context structure. */
+typedef RTFILEAIOCTXINTERNAL *PRTFILEAIOCTXINTERNAL;
+
+/**
+ * Async I/O request state.
+ */
+typedef struct RTFILEAIOREQINTERNAL
+{
+    /** Overlapped structure. */
+    OVERLAPPED            Overlapped;
+    /** Current state the request is in. */
+    RTFILEAIOREQSTATE     enmState;
+    /** The file handle. */
+    HANDLE                hFile;
+    /** Kind of transfer Read/Write. */
+    TRANSFERDIRECTION     enmTransferDirection;
+    /** Number of bytes to transfer. */
+    size_t                cbTransfer;
+    /** Pointer to the buffer. */
+    void                 *pvBuf;
+    /** Opaque user data. */
+    void                 *pvUser;
+    /** Flag whether the request completed. */
+    bool                  fCompleted;
+    /** Number of bytes transferred successfully. */
+    size_t                cbTransfered;
+    /** Error code of the completed request. */
+    int                   Rc;
+    /** Completion context we are assigned to. */
+    PRTFILEAIOCTXINTERNAL pCtxInt;
+    /** Magic value  (RTFILEAIOREQ_MAGIC). */
+    uint32_t              u32Magic;
+} RTFILEAIOREQINTERNAL;
+/** Pointer to an internal request structure. */
+typedef RTFILEAIOREQINTERNAL *PRTFILEAIOREQINTERNAL;
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Id for the wakeup event. */
+#define AIO_CONTEXT_WAKEUP_EVENT 1
+/** Converts a pointer to an OVERLAPPED structure to a internal request. */
+#define OVERLAPPED_2_RTFILEAIOREQINTERNAL(pOverlapped) ( (PRTFILEAIOREQINTERNAL)((uintptr_t)(pOverlapped) - RT_UOFFSETOF(RTFILEAIOREQINTERNAL, Overlapped)) )
+
+RTR3DECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits)
+{
+    AssertPtrReturn(pAioLimits, VERR_INVALID_POINTER);
+
+    /* No limits known. */
+    pAioLimits->cReqsOutstandingMax = RTFILEAIO_UNLIMITED_REQS;
+    pAioLimits->cbBufferAlignment   = 0;
+
+    return VINF_SUCCESS;
+}
+
+RTR3DECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq)
+{
+    AssertPtrReturn(phReq, VERR_INVALID_POINTER);
+
+    PRTFILEAIOREQINTERNAL pReqInt = (PRTFILEAIOREQINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOREQINTERNAL));
+    if (RT_UNLIKELY(!pReqInt))
+        return VERR_NO_MEMORY;
+
+    pReqInt->pCtxInt    = NULL;
+    pReqInt->fCompleted = false;
+    pReqInt->u32Magic   = RTFILEAIOREQ_MAGIC;
+    RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+    *phReq = (RTFILEAIOREQ)pReqInt;
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq)
+{
+    /*
+     * Validate the handle and ignore nil.
+     */
+    if (hReq == NIL_RTFILEAIOREQ)
+        return VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+
+    /*
+     * Trash the magic and free it.
+     */
+    ASMAtomicUoWriteU32(&pReqInt->u32Magic, ~RTFILEAIOREQ_MAGIC);
+    RTMemFree(pReqInt);
+    return VINF_SUCCESS;
+}
+
+/**
+ * Worker setting up the request.
+ */
+DECLINLINE(int) rtFileAioReqPrepareTransfer(RTFILEAIOREQ hReq, RTFILE hFile,
+                                            TRANSFERDIRECTION enmTransferDirection,
+                                            RTFOFF off, void *pvBuf, size_t cbTransfer,
+                                            void *pvUser)
+{
+    /*
+     * Validate the input.
+     */
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    Assert(hFile != NIL_RTFILE);
+    AssertPtr(pvBuf);
+    Assert(off >= 0);
+    Assert(cbTransfer > 0);
+
+    pReqInt->enmTransferDirection  = enmTransferDirection;
+    pReqInt->hFile                 = (HANDLE)RTFileToNative(hFile);
+    pReqInt->Overlapped.Offset     = (DWORD)(off & 0xffffffff);
+    pReqInt->Overlapped.OffsetHigh = (DWORD)(off >> 32);
+    pReqInt->cbTransfer            = cbTransfer;
+    pReqInt->pvBuf                 = pvBuf;
+    pReqInt->pvUser                = pvUser;
+    pReqInt->fCompleted            = false;
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                    void *pvBuf, size_t cbRead, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, TRANSFERDIRECTION_READ,
+                                       off, pvBuf, cbRead, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off,
+                                     void const *pvBuf, size_t cbWrite, void *pvUser)
+{
+    return rtFileAioReqPrepareTransfer(hReq, hFile, TRANSFERDIRECTION_WRITE,
+                                       off, (void *)pvBuf, cbWrite, pvUser);
+}
+
+RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    AssertReturn(hFile != NIL_RTFILE, VERR_INVALID_HANDLE);
+    RT_NOREF_PV(pvUser);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN_RC(pReqInt, NULL);
+
+    return pReqInt->pvUser;
+}
+
+RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq)
+{
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    /**
+     * @todo r=aeichner It is not possible to cancel specific
+     * requests on Windows before Vista.
+     * CancelIo cancels all requests for a file issued by the
+     * calling thread and CancelIoEx which does what we need
+     * is only available from Vista and up.
+     * The solution is to return VERR_FILE_AIO_IN_PROGRESS
+     * if the request didn't completed yet (checked above).
+     * Shouldn't be a big issue because a request is normally
+     * only canceled if it exceeds a timeout which is quite huge.
+     */
+    return VERR_FILE_AIO_COMPLETED;
+}
+
+RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransfered)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOREQINTERNAL pReqInt = hReq;
+    RTFILEAIOREQ_VALID_RETURN(pReqInt);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, SUBMITTED, VERR_FILE_AIO_IN_PROGRESS);
+    RTFILEAIOREQ_NOT_STATE_RETURN_RC(pReqInt, PREPARED, VERR_FILE_AIO_NOT_SUBMITTED);
+
+    rc = pReqInt->Rc;
+    if (pcbTransfered && RT_SUCCESS(rc))
+        *pcbTransfered = pReqInt->cbTransfered;
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax, uint32_t fFlags)
+{
+    AssertPtrReturn(phAioCtx, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTFILEAIOCTX_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+    RT_NOREF_PV(cAioReqsMax);
+
+    if (   g_pfnCreateIoCompletionPort
+        && g_pfnGetQueuedCompletionStatus
+        && g_pfnPostQueuedCompletionStatus)
+    {
+        PRTFILEAIOCTXINTERNAL pCtxInt = (PRTFILEAIOCTXINTERNAL)RTMemAllocZ(sizeof(RTFILEAIOCTXINTERNAL));
+        if (RT_UNLIKELY(!pCtxInt))
+            return VERR_NO_MEMORY;
+
+        pCtxInt->hIoCompletionPort = g_pfnCreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 0);
+        if (RT_UNLIKELY(!pCtxInt->hIoCompletionPort))
+        {
+            RTMemFree(pCtxInt);
+            return VERR_NO_MEMORY;
+        }
+
+        pCtxInt->fFlags   = fFlags;
+        pCtxInt->u32Magic = RTFILEAIOCTX_MAGIC;
+
+        *phAioCtx = (RTFILEAIOCTX)pCtxInt;
+
+        return VINF_SUCCESS;
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx)
+{
+    /* Validate the handle and ignore nil. */
+    if (hAioCtx == NIL_RTFILEAIOCTX)
+        return VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    /* Cannot destroy a busy context. */
+    if (RT_UNLIKELY(pCtxInt->cRequests))
+        return VERR_FILE_AIO_BUSY;
+
+    CloseHandle(pCtxInt->hIoCompletionPort);
+    ASMAtomicUoWriteU32(&pCtxInt->u32Magic, RTFILEAIOCTX_MAGIC_DEAD);
+    RTMemFree(pCtxInt);
+
+    return VINF_SUCCESS;
+}
+
+RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile)
+{
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    if (   g_pfnCreateIoCompletionPort
+        && g_pfnGetQueuedCompletionStatus
+        && g_pfnPostQueuedCompletionStatus)
+    {
+        int rc = VINF_SUCCESS;
+        HANDLE hTemp = g_pfnCreateIoCompletionPort((HANDLE)RTFileToNative(hFile), pCtxInt->hIoCompletionPort, 0, 1);
+        if (hTemp != pCtxInt->hIoCompletionPort)
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        return rc;
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx)
+{
+    RT_NOREF_PV(hAioCtx);
+    return RTFILEAIO_UNLIMITED_REQS;
+}
+
+RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs)
+{
+    /*
+     * Parameter validation.
+     */
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertReturn(cReqs > 0,  VERR_INVALID_PARAMETER);
+    Assert(cReqs <= INT32_MAX);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    size_t i;
+
+    for (i = 0; i < cReqs; i++)
+    {
+        PRTFILEAIOREQINTERNAL pReqInt = pahReqs[i];
+        BOOL fSucceeded;
+
+        Assert(pReqInt->cbTransfer == (DWORD)pReqInt->cbTransfer);
+        if (pReqInt->enmTransferDirection == TRANSFERDIRECTION_READ)
+        {
+            fSucceeded = ReadFile(pReqInt->hFile, pReqInt->pvBuf,
+                                  (DWORD)pReqInt->cbTransfer, NULL,
+                                  &pReqInt->Overlapped);
+        }
+        else if (pReqInt->enmTransferDirection == TRANSFERDIRECTION_WRITE)
+        {
+            fSucceeded = WriteFile(pReqInt->hFile, pReqInt->pvBuf,
+                                   (DWORD)pReqInt->cbTransfer, NULL,
+                                   &pReqInt->Overlapped);
+        }
+        else
+        {
+            fSucceeded = false;
+            AssertMsgFailed(("Invalid transfer direction\n"));
+        }
+
+        if (RT_UNLIKELY(!fSucceeded && GetLastError() != ERROR_IO_PENDING))
+        {
+            RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+            rc = RTErrConvertFromWin32(GetLastError());
+            pReqInt->Rc = rc;
+            break;
+        }
+        RTFILEAIOREQ_SET_STATE(pReqInt, SUBMITTED);
+    }
+
+    ASMAtomicAddS32(&pCtxInt->cRequests, (int32_t)i);
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies,
+                             PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs)
+{
+    /*
+     * Validate the parameters, making sure to always set pcReqs.
+     */
+    AssertPtrReturn(pcReqs, VERR_INVALID_POINTER);
+    *pcReqs = 0; /* always set */
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+    AssertPtrReturn(pahReqs, VERR_INVALID_POINTER);
+    AssertReturn(cReqs != 0, VERR_INVALID_PARAMETER);
+    AssertReturn(cReqs >= cMinReqs, VERR_OUT_OF_RANGE);
+
+    /*
+     * Can't wait if there are no requests around.
+     */
+    if (   RT_UNLIKELY(ASMAtomicUoReadS32(&pCtxInt->cRequests) == 0)
+        && !(pCtxInt->fFlags & RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS))
+        return VERR_FILE_AIO_NO_REQUEST;
+
+    /* Wait for at least one. */
+    if (!cMinReqs)
+        cMinReqs = 1;
+
+    /*
+     * Loop until we're woken up, hit an error (incl timeout), or
+     * have collected the desired number of requests.
+     */
+    int rc = VINF_SUCCESS;
+    int cRequestsCompleted = 0;
+    while (   !pCtxInt->fWokenUp
+           && cMinReqs > 0)
+    {
+        uint64_t     StartNanoTS = 0;
+        DWORD        dwTimeout = cMillies == RT_INDEFINITE_WAIT ? INFINITE : cMillies;
+        DWORD        cbTransfered;
+        LPOVERLAPPED pOverlapped;
+        ULONG_PTR    lCompletionKey;
+        BOOL         fSucceeded;
+
+        if (cMillies != RT_INDEFINITE_WAIT)
+            StartNanoTS = RTTimeNanoTS();
+
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, true);
+        fSucceeded = g_pfnGetQueuedCompletionStatus(pCtxInt->hIoCompletionPort,
+                                                    &cbTransfered,
+                                                    &lCompletionKey,
+                                                    &pOverlapped,
+                                                    dwTimeout);
+        ASMAtomicXchgBool(&pCtxInt->fWaiting, false);
+        if (   !fSucceeded
+            && !pOverlapped)
+        {
+            /* The call failed to dequeue a completion packet, includes VERR_TIMEOUT */
+            rc = RTErrConvertFromWin32(GetLastError());
+            break;
+        }
+
+        /* Check if we got woken up. */
+        if (lCompletionKey == AIO_CONTEXT_WAKEUP_EVENT)
+        {
+            Assert(fSucceeded && !pOverlapped);
+            break;
+        }
+
+        /* A request completed. */
+        PRTFILEAIOREQINTERNAL pReqInt = OVERLAPPED_2_RTFILEAIOREQINTERNAL(pOverlapped);
+        AssertPtr(pReqInt);
+        Assert(pReqInt->u32Magic == RTFILEAIOREQ_MAGIC);
+
+        /* Mark the request as finished. */
+        RTFILEAIOREQ_SET_STATE(pReqInt, COMPLETED);
+
+        pReqInt->cbTransfered = cbTransfered;
+        if (fSucceeded)
+            pReqInt->Rc = VINF_SUCCESS;
+        else
+        {
+            DWORD errCode = GetLastError();
+            pReqInt->Rc = RTErrConvertFromWin32(errCode);
+            if (pReqInt->Rc == VERR_UNRESOLVED_ERROR)
+                LogRel(("AIO/win: Request %#p returned rc=%Rrc (native %u\n)", pReqInt, pReqInt->Rc, errCode));
+        }
+
+        pahReqs[cRequestsCompleted++] = (RTFILEAIOREQ)pReqInt;
+
+        /* Update counter. */
+        cMinReqs--;
+
+        if (cMillies != RT_INDEFINITE_WAIT)
+        {
+            /* Recalculate timeout. */
+            uint64_t NanoTS = RTTimeNanoTS();
+            uint64_t cMilliesElapsed = (NanoTS - StartNanoTS) / 1000000;
+            if (cMilliesElapsed < cMillies)
+                cMillies -= cMilliesElapsed;
+            else
+                cMillies = 0;
+        }
+    }
+
+    /*
+     * Update the context state and set the return value.
+     */
+    *pcReqs = cRequestsCompleted;
+    ASMAtomicSubS32(&pCtxInt->cRequests, cRequestsCompleted);
+
+    /*
+     * Clear the wakeup flag and set rc.
+     */
+    bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUp, false);
+
+    if (    fWokenUp
+        &&  RT_SUCCESS(rc))
+        rc = VERR_INTERRUPTED;
+
+    return rc;
+}
+
+RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx)
+{
+    int rc = VINF_SUCCESS;
+    PRTFILEAIOCTXINTERNAL pCtxInt = hAioCtx;
+    RTFILEAIOCTX_VALID_RETURN(pCtxInt);
+
+    bool fWokenUp = ASMAtomicXchgBool(&pCtxInt->fWokenUp, true);
+    bool fWaiting = ASMAtomicReadBool(&pCtxInt->fWaiting);
+
+    if (   !fWokenUp
+        && fWaiting)
+    {
+        BOOL fSucceeded = g_pfnPostQueuedCompletionStatus(pCtxInt->hIoCompletionPort,
+                                                          0, AIO_CONTEXT_WAKEUP_EVENT,
+                                                          NULL);
+
+        if (!fSucceeded)
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/fileio-win.cpp b/src/VBox/Runtime/r3/win/fileio-win.cpp
new file mode 100644
index 00000000..3feba3a2
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/fileio-win.cpp
@@ -0,0 +1,1549 @@
+/* $Id: fileio-win.cpp $ */
+/** @file
+ * IPRT - File I/O, native implementation for the Windows host platform.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DIR
+#ifndef _WIN32_WINNT
+# define _WIN32_WINNT 0x0500
+#endif
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/file.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/utf16.h>
+#include "internal/file.h"
+#include "internal/fs.h"
+#include "internal/path.h"
+#include "internal-r3-win.h" /* For g_enmWinVer + kRTWinOSType_XXX */
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+typedef BOOL WINAPI FNVERIFYCONSOLEIOHANDLE(HANDLE);
+typedef FNVERIFYCONSOLEIOHANDLE *PFNVERIFYCONSOLEIOHANDLE; /* No, nobody fell on the keyboard, really! */
+
+
+/**
+ * This is wrapper around the ugly SetFilePointer api.
+ *
+ * It's equivalent to SetFilePointerEx which we so unfortunately cannot use because of
+ * it not being present in NT4 GA.
+ *
+ * @returns Success indicator. Extended error information obtainable using GetLastError().
+ * @param   hFile       Filehandle.
+ * @param   offSeek     Offset to seek.
+ * @param   poffNew     Where to store the new file offset. NULL allowed.
+ * @param   uMethod     Seek method. (The windows one!)
+ */
+DECLINLINE(bool) MySetFilePointer(RTFILE hFile, uint64_t offSeek, uint64_t *poffNew, unsigned uMethod)
+{
+    bool            fRc;
+    LARGE_INTEGER   off;
+
+    off.QuadPart = offSeek;
+#if 1
+    if (off.LowPart != INVALID_SET_FILE_POINTER)
+    {
+        off.LowPart = SetFilePointer((HANDLE)RTFileToNative(hFile), off.LowPart, &off.HighPart, uMethod);
+        fRc = off.LowPart != INVALID_SET_FILE_POINTER;
+    }
+    else
+    {
+        SetLastError(NO_ERROR);
+        off.LowPart = SetFilePointer((HANDLE)RTFileToNative(hFile), off.LowPart, &off.HighPart, uMethod);
+        fRc = GetLastError() == NO_ERROR;
+    }
+#else
+    fRc = SetFilePointerEx((HANDLE)RTFileToNative(hFile), off, &off, uMethod);
+#endif
+    if (fRc && poffNew)
+        *poffNew = off.QuadPart;
+    return fRc;
+}
+
+
+/**
+ * Helper for checking if a VERR_DISK_FULL isn't a VERR_FILE_TOO_BIG.
+ * @returns VERR_DISK_FULL or VERR_FILE_TOO_BIG.
+ */
+static int rtFileWinCheckIfDiskReallyFull(RTFILE hFile, uint64_t cbDesired)
+{
+    /*
+     * Windows doesn't appear to have a way to query the file size limit of a
+     * file system, so we have to deduce the limit from the file system driver name.
+     * This means it will only work for known file systems.
+     */
+    if (cbDesired >= _2G - 1)
+    {
+        uint64_t cbMaxFile = UINT64_MAX;
+        RTFSTYPE enmFsType;
+        int rc = rtNtQueryFsType((HANDLE)RTFileToNative(hFile), &enmFsType);
+        if (RT_SUCCESS(rc))
+            switch (enmFsType)
+            {
+                case RTFSTYPE_NTFS:
+                case RTFSTYPE_EXFAT:
+                case RTFSTYPE_UDF:
+                    cbMaxFile = UINT64_C(0xffffffffffffffff); /* (May be limited by IFS.) */
+                    break;
+
+                case RTFSTYPE_ISO9660:
+                    cbMaxFile = 8 *_1T;
+                    break;
+
+                case RTFSTYPE_FAT:
+                    cbMaxFile = _4G;
+                    break;
+
+                case RTFSTYPE_HPFS:
+                    cbMaxFile = _2G;
+                    break;
+
+                default:
+                    break;
+            }
+        if (cbDesired >= cbMaxFile)
+            return VERR_FILE_TOO_BIG;
+    }
+    return VERR_DISK_FULL;
+}
+
+
+RTR3DECL(int) RTFileFromNative(PRTFILE pFile, RTHCINTPTR uNative)
+{
+    HANDLE h = (HANDLE)uNative;
+    AssertCompile(sizeof(h) == sizeof(uNative));
+    if (h == INVALID_HANDLE_VALUE)
+    {
+        AssertMsgFailed(("%p\n", uNative));
+        *pFile = NIL_RTFILE;
+        return VERR_INVALID_HANDLE;
+    }
+    *pFile = (RTFILE)h;
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(RTHCINTPTR) RTFileToNative(RTFILE hFile)
+{
+    AssertReturn(hFile != NIL_RTFILE, (RTHCINTPTR)INVALID_HANDLE_VALUE);
+    return (RTHCINTPTR)hFile;
+}
+
+
+RTR3DECL(int) RTFileOpen(PRTFILE pFile, const char *pszFilename, uint64_t fOpen)
+{
+    return RTFileOpenEx(pszFilename, fOpen, pFile, NULL);
+}
+
+
+RTDECL(int) RTFileOpenEx(const char *pszFilename, uint64_t fOpen, PRTFILE phFile, PRTFILEACTION penmActionTaken)
+{
+    /*
+     * Validate input.
+     */
+    AssertReturn(phFile, VERR_INVALID_PARAMETER);
+    *phFile = NIL_RTFILE;
+    if (penmActionTaken)
+        *penmActionTaken = RTFILEACTION_INVALID;
+    AssertReturn(pszFilename, VERR_INVALID_PARAMETER);
+
+    /*
+     * Merge forced open flags and validate them.
+     */
+    int rc = rtFileRecalcAndValidateFlags(&fOpen);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Determine disposition, access, share mode, creation flags, and security attributes
+     * for the CreateFile API call.
+     */
+    DWORD dwCreationDisposition;
+    switch (fOpen & RTFILE_O_ACTION_MASK)
+    {
+        case RTFILE_O_OPEN:
+            dwCreationDisposition = fOpen & RTFILE_O_TRUNCATE ? TRUNCATE_EXISTING : OPEN_EXISTING;
+            break;
+        case RTFILE_O_OPEN_CREATE:
+            dwCreationDisposition = OPEN_ALWAYS;
+            break;
+        case RTFILE_O_CREATE:
+            dwCreationDisposition = CREATE_NEW;
+            break;
+        case RTFILE_O_CREATE_REPLACE:
+            dwCreationDisposition = CREATE_ALWAYS;
+            break;
+        default:
+            AssertMsgFailedReturn(("Impossible fOpen=%#llx\n", fOpen), VERR_INVALID_FLAGS);
+    }
+
+    DWORD dwDesiredAccess;
+    switch (fOpen & RTFILE_O_ACCESS_MASK)
+    {
+        case RTFILE_O_READ:
+            dwDesiredAccess = FILE_GENERIC_READ; /* RTFILE_O_APPEND is ignored. */
+            break;
+        case RTFILE_O_WRITE:
+            dwDesiredAccess = fOpen & RTFILE_O_APPEND
+                            ? FILE_GENERIC_WRITE & ~FILE_WRITE_DATA
+                            : FILE_GENERIC_WRITE;
+            break;
+        case RTFILE_O_READWRITE:
+            dwDesiredAccess = fOpen & RTFILE_O_APPEND
+                            ? FILE_GENERIC_READ | (FILE_GENERIC_WRITE & ~FILE_WRITE_DATA)
+                            : FILE_GENERIC_READ | FILE_GENERIC_WRITE;
+            break;
+        case RTFILE_O_ATTR_ONLY:
+            if (fOpen & RTFILE_O_ACCESS_ATTR_MASK)
+            {
+                dwDesiredAccess = 0;
+                break;
+            }
+            RT_FALL_THRU();
+        default:
+            AssertMsgFailedReturn(("Impossible fOpen=%#llx\n", fOpen), VERR_INVALID_FLAGS);
+    }
+    if (dwCreationDisposition == TRUNCATE_EXISTING)
+        /* Required for truncating the file (see MSDN), it is *NOT* part of FILE_GENERIC_WRITE. */
+        dwDesiredAccess |= GENERIC_WRITE;
+
+    /* RTFileSetMode needs following rights as well. */
+    switch (fOpen & RTFILE_O_ACCESS_ATTR_MASK)
+    {
+        case RTFILE_O_ACCESS_ATTR_READ:      dwDesiredAccess |= FILE_READ_ATTRIBUTES  | SYNCHRONIZE; break;
+        case RTFILE_O_ACCESS_ATTR_WRITE:     dwDesiredAccess |= FILE_WRITE_ATTRIBUTES | SYNCHRONIZE; break;
+        case RTFILE_O_ACCESS_ATTR_READWRITE: dwDesiredAccess |= FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES | SYNCHRONIZE; break;
+        default:
+            /* Attributes access is the same as the file access. */
+            switch (fOpen & RTFILE_O_ACCESS_MASK)
+            {
+                case RTFILE_O_READ:          dwDesiredAccess |= FILE_READ_ATTRIBUTES  | SYNCHRONIZE; break;
+                case RTFILE_O_WRITE:         dwDesiredAccess |= FILE_WRITE_ATTRIBUTES | SYNCHRONIZE; break;
+                case RTFILE_O_READWRITE:     dwDesiredAccess |= FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES | SYNCHRONIZE; break;
+                default:
+                    AssertMsgFailedReturn(("Impossible fOpen=%#llx\n", fOpen), VERR_INVALID_FLAGS);
+            }
+    }
+
+    DWORD dwShareMode;
+    switch (fOpen & RTFILE_O_DENY_MASK)
+    {
+        case RTFILE_O_DENY_NONE:                                dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE; break;
+        case RTFILE_O_DENY_READ:                                dwShareMode = FILE_SHARE_WRITE; break;
+        case RTFILE_O_DENY_WRITE:                               dwShareMode = FILE_SHARE_READ; break;
+        case RTFILE_O_DENY_READWRITE:                           dwShareMode = 0; break;
+
+        case RTFILE_O_DENY_NOT_DELETE:                          dwShareMode = FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE; break;
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_READ:     dwShareMode = FILE_SHARE_DELETE | FILE_SHARE_WRITE; break;
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_WRITE:    dwShareMode = FILE_SHARE_DELETE | FILE_SHARE_READ; break;
+        case RTFILE_O_DENY_NOT_DELETE | RTFILE_O_DENY_READWRITE:dwShareMode = FILE_SHARE_DELETE; break;
+        default:
+            AssertMsgFailedReturn(("Impossible fOpen=%#llx\n", fOpen), VERR_INVALID_FLAGS);
+    }
+
+    SECURITY_ATTRIBUTES  SecurityAttributes;
+    PSECURITY_ATTRIBUTES pSecurityAttributes = NULL;
+    if (fOpen & RTFILE_O_INHERIT)
+    {
+        SecurityAttributes.nLength              = sizeof(SecurityAttributes);
+        SecurityAttributes.lpSecurityDescriptor = NULL;
+        SecurityAttributes.bInheritHandle       = TRUE;
+        pSecurityAttributes = &SecurityAttributes;
+    }
+
+    DWORD dwFlagsAndAttributes;
+    dwFlagsAndAttributes = !(fOpen & RTFILE_O_TEMP_AUTO_DELETE) ? FILE_ATTRIBUTE_NORMAL : FILE_ATTRIBUTE_TEMPORARY;
+    if (fOpen & RTFILE_O_TEMP_AUTO_DELETE)
+        fOpen |= FILE_FLAG_DELETE_ON_CLOSE;
+    if (fOpen & RTFILE_O_WRITE_THROUGH)
+        dwFlagsAndAttributes |= FILE_FLAG_WRITE_THROUGH;
+    if (fOpen & RTFILE_O_ASYNC_IO)
+        dwFlagsAndAttributes |= FILE_FLAG_OVERLAPPED;
+    if (fOpen & RTFILE_O_NO_CACHE)
+    {
+        dwFlagsAndAttributes |= FILE_FLAG_NO_BUFFERING;
+        dwDesiredAccess &= ~FILE_APPEND_DATA;
+    }
+
+    /*
+     * Open/Create the file.
+     */
+    PRTUTF16 pwszFilename;
+    rc = RTPathWinFromUtf8(&pwszFilename, pszFilename, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE hFile = CreateFileW(pwszFilename,
+                                   dwDesiredAccess,
+                                   dwShareMode,
+                                   pSecurityAttributes,
+                                   dwCreationDisposition,
+                                   dwFlagsAndAttributes,
+                                   NULL);
+        DWORD const dwErr = GetLastError();
+        if (hFile != INVALID_HANDLE_VALUE)
+        {
+            /*
+             * Calculate the action taken value.
+             */
+            RTFILEACTION enmActionTaken;
+            switch (dwCreationDisposition)
+            {
+                case CREATE_NEW:
+                    enmActionTaken = RTFILEACTION_CREATED;
+                    break;
+                case CREATE_ALWAYS:
+                    AssertMsg(dwErr == ERROR_ALREADY_EXISTS || dwErr == NO_ERROR, ("%u\n", dwErr));
+                    enmActionTaken = dwErr == ERROR_ALREADY_EXISTS ? RTFILEACTION_REPLACED : RTFILEACTION_CREATED;
+                    break;
+                case OPEN_EXISTING:
+                    enmActionTaken = RTFILEACTION_OPENED;
+                    break;
+                case OPEN_ALWAYS:
+                    AssertMsg(dwErr == ERROR_ALREADY_EXISTS || dwErr == NO_ERROR, ("%u\n", dwErr));
+                    enmActionTaken = dwErr == ERROR_ALREADY_EXISTS ? RTFILEACTION_OPENED : RTFILEACTION_CREATED;
+                    break;
+                case TRUNCATE_EXISTING:
+                    enmActionTaken = RTFILEACTION_TRUNCATED;
+                    break;
+                default:
+                    AssertMsgFailed(("%d %#x\n", dwCreationDisposition, dwCreationDisposition));
+                    enmActionTaken = RTFILEACTION_INVALID;
+                    break;
+            }
+
+            /*
+             * Turn off indexing of directory through Windows Indexing Service if
+             * we created a new file or replaced an existing one.
+             */
+            if (   (fOpen & RTFILE_O_NOT_CONTENT_INDEXED)
+                && (   enmActionTaken == RTFILEACTION_CREATED
+                    || enmActionTaken == RTFILEACTION_REPLACED) )
+            {
+                /** @todo there must be a way to do this via the handle! */
+                if (!SetFileAttributesW(pwszFilename, FILE_ATTRIBUTE_NOT_CONTENT_INDEXED))
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            /*
+             * If RTFILEACTION_OPENED, we may need to truncate the file.
+             */
+            else if (  (fOpen & (RTFILE_O_TRUNCATE | RTFILE_O_ACTION_MASK)) == (RTFILE_O_TRUNCATE | RTFILE_O_OPEN_CREATE)
+                     && enmActionTaken == RTFILEACTION_OPENED)
+            {
+                if (SetEndOfFile(hFile))
+                    enmActionTaken = RTFILEACTION_TRUNCATED;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            if (penmActionTaken)
+                *penmActionTaken = enmActionTaken;
+            if (RT_SUCCESS(rc))
+            {
+                *phFile = (RTFILE)hFile;
+                Assert((HANDLE)*phFile == hFile);
+                RTPathWinFree(pwszFilename);
+                return VINF_SUCCESS;
+            }
+
+            CloseHandle(hFile);
+        }
+        else
+        {
+            if (   penmActionTaken
+                && dwCreationDisposition == CREATE_NEW
+                && dwErr == ERROR_FILE_EXISTS)
+                *penmActionTaken = RTFILEACTION_ALREADY_EXISTS;
+            rc = RTErrConvertFromWin32(dwErr);
+        }
+        RTPathWinFree(pwszFilename);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int)  RTFileOpenBitBucket(PRTFILE phFile, uint64_t fAccess)
+{
+    AssertReturn(   fAccess == RTFILE_O_READ
+                 || fAccess == RTFILE_O_WRITE
+                 || fAccess == RTFILE_O_READWRITE,
+                 VERR_INVALID_PARAMETER);
+    return RTFileOpen(phFile, "NUL", fAccess | RTFILE_O_DENY_NONE | RTFILE_O_OPEN);
+}
+
+
+RTDECL(int)  RTFileDup(RTFILE hFileSrc, uint64_t fFlags, PRTFILE phFileNew)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phFileNew, VERR_INVALID_POINTER);
+    *phFileNew = NIL_RTFILE;
+    AssertPtrReturn(phFileNew, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~(uint64_t)RTFILE_O_INHERIT), VERR_INVALID_FLAGS);
+
+    /*
+     * Do the job.
+     */
+    HANDLE hNew = INVALID_HANDLE_VALUE;
+    if (DuplicateHandle(GetCurrentProcess(), (HANDLE)RTFileToNative(hFileSrc),
+                        GetCurrentProcess(), &hNew, 0, RT_BOOL(fFlags & RTFILE_O_INHERIT), DUPLICATE_SAME_ACCESS))
+    {
+        *phFileNew = (RTFILE)hNew;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTR3DECL(int)  RTFileClose(RTFILE hFile)
+{
+    if (hFile == NIL_RTFILE)
+        return VINF_SUCCESS;
+    if (CloseHandle((HANDLE)RTFileToNative(hFile)))
+        return VINF_SUCCESS;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTFILE rtFileGetStandard(RTHANDLESTD enmStdHandle)
+{
+    DWORD dwStdHandle;
+    switch (enmStdHandle)
+    {
+        case RTHANDLESTD_INPUT:     dwStdHandle = STD_INPUT_HANDLE;  break;
+        case RTHANDLESTD_OUTPUT:    dwStdHandle = STD_OUTPUT_HANDLE; break;
+        case RTHANDLESTD_ERROR:     dwStdHandle = STD_ERROR_HANDLE;  break;
+        default:
+            AssertFailedReturn(NIL_RTFILE);
+    }
+
+    HANDLE hNative = GetStdHandle(dwStdHandle);
+    if (hNative == INVALID_HANDLE_VALUE)
+        return NIL_RTFILE;
+
+    RTFILE hFile = (RTFILE)(uintptr_t)hNative;
+    AssertReturn((HANDLE)(uintptr_t)hFile == hNative, NIL_RTFILE);
+    return hFile;
+}
+
+
+RTR3DECL(int)  RTFileSeek(RTFILE hFile, int64_t offSeek, unsigned uMethod, uint64_t *poffActual)
+{
+    static ULONG aulSeekRecode[] =
+    {
+        FILE_BEGIN,
+        FILE_CURRENT,
+        FILE_END,
+    };
+
+    /*
+     * Validate input.
+     */
+    if (uMethod > RTFILE_SEEK_END)
+    {
+        AssertMsgFailed(("Invalid uMethod=%d\n", uMethod));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Execute the seek.
+     */
+    if (MySetFilePointer(hFile, offSeek, poffActual, aulSeekRecode[uMethod]))
+        return VINF_SUCCESS;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTR3DECL(int)  RTFileRead(RTFILE hFile, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    if (cbToRead <= 0)
+    {
+        if (pcbRead)
+            *pcbRead = 0;
+        return VINF_SUCCESS;
+    }
+    ULONG cbToReadAdj = (ULONG)cbToRead;
+    AssertReturn(cbToReadAdj == cbToRead, VERR_NUMBER_TOO_BIG);
+
+    ULONG cbRead = 0;
+    if (ReadFile((HANDLE)RTFileToNative(hFile), pvBuf, cbToReadAdj, &cbRead, NULL))
+    {
+        if (pcbRead)
+            /* Caller can handle partial reads. */
+            *pcbRead = cbRead;
+        else
+        {
+            /* Caller expects everything to be read. */
+            while (cbToReadAdj > cbRead)
+            {
+                ULONG cbReadPart = 0;
+                if (!ReadFile((HANDLE)RTFileToNative(hFile), (char*)pvBuf + cbRead, cbToReadAdj - cbRead, &cbReadPart, NULL))
+                    return RTErrConvertFromWin32(GetLastError());
+                if (cbReadPart == 0)
+                    return VERR_EOF;
+                cbRead += cbReadPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * If it's a console, we might bump into out of memory conditions in the
+     * ReadConsole call.
+     */
+    DWORD dwErr = GetLastError();
+    if (dwErr == ERROR_NOT_ENOUGH_MEMORY)
+    {
+        ULONG cbChunk = cbToReadAdj / 2;
+        if (cbChunk > 16*_1K)
+            cbChunk = 16*_1K;
+        else
+            cbChunk = RT_ALIGN_32(cbChunk, 256);
+
+        cbRead = 0;
+        while (cbToReadAdj > cbRead)
+        {
+            ULONG cbToReadNow = RT_MIN(cbChunk, cbToReadAdj - cbRead);
+            ULONG cbReadPart  = 0;
+            if (!ReadFile((HANDLE)RTFileToNative(hFile), (char *)pvBuf + cbRead, cbToReadNow, &cbReadPart, NULL))
+            {
+                /* If we failed because the buffer is too big, shrink it and
+                   try again. */
+                dwErr = GetLastError();
+                if (   dwErr == ERROR_NOT_ENOUGH_MEMORY
+                    && cbChunk > 8)
+                {
+                    cbChunk /= 2;
+                    continue;
+                }
+                return RTErrConvertFromWin32(dwErr);
+            }
+            cbRead += cbReadPart;
+
+            /* Return if the caller can handle partial reads, otherwise try
+               fill the buffer all the way up. */
+            if (pcbRead)
+            {
+                *pcbRead = cbRead;
+                break;
+            }
+            if (cbReadPart == 0)
+                return VERR_EOF;
+        }
+        return VINF_SUCCESS;
+    }
+
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+RTDECL(int)  RTFileReadAt(RTFILE hFile, RTFOFF off, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    ULONG cbToReadAdj = (ULONG)cbToRead;
+    AssertReturn(cbToReadAdj == cbToRead, VERR_NUMBER_TOO_BIG);
+
+    OVERLAPPED Overlapped;
+    Overlapped.Offset       = (uint32_t)off;
+    Overlapped.OffsetHigh   = (uint32_t)(off >> 32);
+    Overlapped.hEvent       = NULL;
+    Overlapped.Internal     = 0;
+    Overlapped.InternalHigh = 0;
+
+    ULONG cbRead = 0;
+    if (ReadFile((HANDLE)RTFileToNative(hFile), pvBuf, cbToReadAdj, &cbRead, &Overlapped))
+    {
+        if (pcbRead)
+            /* Caller can handle partial reads. */
+            *pcbRead = cbRead;
+        else
+        {
+            /* Caller expects everything to be read. */
+            while (cbToReadAdj > cbRead)
+            {
+                Overlapped.Offset       = (uint32_t)(off + cbRead);
+                Overlapped.OffsetHigh   = (uint32_t)((off + cbRead) >> 32);
+                Overlapped.hEvent       = NULL;
+                Overlapped.Internal     = 0;
+                Overlapped.InternalHigh = 0;
+
+                ULONG cbReadPart = 0;
+                if (!ReadFile((HANDLE)RTFileToNative(hFile), (char *)pvBuf + cbRead, cbToReadAdj - cbRead,
+                              &cbReadPart, &Overlapped))
+                    return RTErrConvertFromWin32(GetLastError());
+                if (cbReadPart == 0)
+                    return VERR_EOF;
+                cbRead += cbReadPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    /* We will get an EOF error when using overlapped I/O.  So, make sure we don't
+       return it when pcbhRead is not NULL. */
+    DWORD dwErr = GetLastError();
+    if (pcbRead && dwErr == ERROR_HANDLE_EOF)
+    {
+        *pcbRead = 0;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+RTR3DECL(int)  RTFileWrite(RTFILE hFile, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    if (cbToWrite <= 0)
+        return VINF_SUCCESS;
+    ULONG const cbToWriteAdj = (ULONG)cbToWrite;
+    AssertReturn(cbToWriteAdj == cbToWrite, VERR_NUMBER_TOO_BIG);
+
+    ULONG cbWritten = 0;
+    if (WriteFile((HANDLE)RTFileToNative(hFile), pvBuf, cbToWriteAdj, &cbWritten, NULL))
+    {
+        if (pcbWritten)
+            /* Caller can handle partial writes. */
+            *pcbWritten = RT_MIN(cbWritten, cbToWriteAdj); /* paranoia^3 */
+        else
+        {
+            /* Caller expects everything to be written. */
+            while (cbWritten < cbToWriteAdj)
+            {
+                ULONG cbWrittenPart = 0;
+                if (!WriteFile((HANDLE)RTFileToNative(hFile), (char*)pvBuf + cbWritten,
+                               cbToWriteAdj - cbWritten, &cbWrittenPart, NULL))
+                {
+                    int rc = RTErrConvertFromWin32(GetLastError());
+                    if (rc == VERR_DISK_FULL)
+                        rc = rtFileWinCheckIfDiskReallyFull(hFile, RTFileTell(hFile) + cbToWriteAdj - cbWritten);
+                    return rc;
+                }
+                if (cbWrittenPart == 0)
+                    return VERR_WRITE_ERROR;
+                cbWritten += cbWrittenPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * If it's a console, we might bump into out of memory conditions in the
+     * WriteConsole call.
+     */
+    DWORD dwErr = GetLastError();
+    if (dwErr == ERROR_NOT_ENOUGH_MEMORY)
+    {
+        ULONG cbChunk = cbToWriteAdj / 2;
+        if (cbChunk > _32K)
+            cbChunk = _32K;
+        else
+            cbChunk = RT_ALIGN_32(cbChunk, 256);
+
+        cbWritten = 0;
+        while (cbWritten < cbToWriteAdj)
+        {
+            ULONG cbToWriteNow  = RT_MIN(cbChunk, cbToWriteAdj - cbWritten);
+            ULONG cbWrittenPart = 0;
+            if (!WriteFile((HANDLE)RTFileToNative(hFile), (const char *)pvBuf + cbWritten, cbToWriteNow, &cbWrittenPart, NULL))
+            {
+                /* If we failed because the buffer is too big, shrink it and
+                   try again. */
+                dwErr = GetLastError();
+                if (   dwErr == ERROR_NOT_ENOUGH_MEMORY
+                    && cbChunk > 8)
+                {
+                    cbChunk /= 2;
+                    continue;
+                }
+                int rc = RTErrConvertFromWin32(dwErr);
+                if (rc == VERR_DISK_FULL)
+                    rc = rtFileWinCheckIfDiskReallyFull(hFile, RTFileTell(hFile) + cbToWriteNow);
+                return rc;
+            }
+            cbWritten += cbWrittenPart;
+
+            /* Return if the caller can handle partial writes, otherwise try
+               write out everything. */
+            if (pcbWritten)
+            {
+                *pcbWritten = RT_MIN(cbWritten, cbToWriteAdj); /* paranoia^3 */
+                break;
+            }
+            if (cbWrittenPart == 0)
+                return VERR_WRITE_ERROR;
+        }
+        return VINF_SUCCESS;
+    }
+
+    int rc = RTErrConvertFromWin32(dwErr);
+    if (rc == VERR_DISK_FULL)
+        rc = rtFileWinCheckIfDiskReallyFull(hFile, RTFileTell(hFile) + cbToWriteAdj);
+    return rc;
+}
+
+
+RTDECL(int)  RTFileWriteAt(RTFILE hFile, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    ULONG const cbToWriteAdj = (ULONG)cbToWrite;
+    AssertReturn(cbToWriteAdj == cbToWrite, VERR_NUMBER_TOO_BIG);
+
+    OVERLAPPED Overlapped;
+    Overlapped.Offset       = (uint32_t)off;
+    Overlapped.OffsetHigh   = (uint32_t)(off >> 32);
+    Overlapped.hEvent       = NULL;
+    Overlapped.Internal     = 0;
+    Overlapped.InternalHigh = 0;
+
+    ULONG cbWritten = 0;
+    if (WriteFile((HANDLE)RTFileToNative(hFile), pvBuf, cbToWriteAdj, &cbWritten, &Overlapped))
+    {
+        if (pcbWritten)
+            /* Caller can handle partial writes. */
+            *pcbWritten = RT_MIN(cbWritten, cbToWriteAdj); /* paranoia^3 */
+        else
+        {
+            /* Caller expects everything to be written. */
+            while (cbWritten < cbToWriteAdj)
+            {
+                Overlapped.Offset       = (uint32_t)(off + cbWritten);
+                Overlapped.OffsetHigh   = (uint32_t)((off + cbWritten) >> 32);
+                Overlapped.hEvent       = NULL;
+                Overlapped.Internal     = 0;
+                Overlapped.InternalHigh = 0;
+
+                ULONG cbWrittenPart = 0;
+                if (!WriteFile((HANDLE)RTFileToNative(hFile), (char*)pvBuf + cbWritten,
+                               cbToWriteAdj - cbWritten, &cbWrittenPart, &Overlapped))
+                {
+                    int rc = RTErrConvertFromWin32(GetLastError());
+                    if (rc == VERR_DISK_FULL)
+                        rc = rtFileWinCheckIfDiskReallyFull(hFile, off + cbToWriteAdj);
+                    return rc;
+                }
+                if (cbWrittenPart == 0)
+                    return VERR_WRITE_ERROR;
+                cbWritten += cbWrittenPart;
+            }
+        }
+        return VINF_SUCCESS;
+    }
+
+    int rc = RTErrConvertFromWin32(GetLastError());
+    if (rc == VERR_DISK_FULL)
+        rc = rtFileWinCheckIfDiskReallyFull(hFile, off + cbToWriteAdj);
+    return rc;
+}
+
+
+RTR3DECL(int)  RTFileFlush(RTFILE hFile)
+{
+    if (!FlushFileBuffers((HANDLE)RTFileToNative(hFile)))
+    {
+        int rc = GetLastError();
+        Log(("FlushFileBuffers failed with %d\n", rc));
+        return RTErrConvertFromWin32(rc);
+    }
+    return VINF_SUCCESS;
+}
+
+#if 1
+
+/**
+ * Checks the the two handles refers to the same file.
+ *
+ * @returns true if the same file, false if different ones or invalid handles.
+ * @param   hFile1              Handle \#1.
+ * @param   hFile2              Handle \#2.
+ */
+static bool rtFileIsSame(HANDLE hFile1, HANDLE hFile2)
+{
+    /*
+     * We retry in case CreationTime or the Object ID is being modified and there
+     * aren't any IndexNumber (file ID) on this kind of file system.
+     */
+    for (uint32_t iTries = 0; iTries < 3; iTries++)
+    {
+        /*
+         * Fetch data to compare (being a little lazy here).
+         */
+        struct
+        {
+            HANDLE                      hFile;
+            NTSTATUS                    rcObjId;
+            FILE_OBJECTID_INFORMATION   ObjId;
+            FILE_ALL_INFORMATION        All;
+            FILE_FS_VOLUME_INFORMATION  Vol;
+        } auData[2];
+        auData[0].hFile = hFile1;
+        auData[1].hFile = hFile2;
+
+        for (uintptr_t i = 0; i < RT_ELEMENTS(auData); i++)
+        {
+            RT_ZERO(auData[i].ObjId);
+            IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+            auData[i].rcObjId = NtQueryInformationFile(auData[i].hFile, &Ios, &auData[i].ObjId, sizeof(auData[i].ObjId),
+                                                       FileObjectIdInformation);
+
+            RT_ZERO(auData[i].All);
+            RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+            NTSTATUS rcNt = NtQueryInformationFile(auData[i].hFile, &Ios, &auData[i].All, sizeof(auData[i].All),
+                                                   FileAllInformation);
+            AssertReturn(rcNt == STATUS_BUFFER_OVERFLOW /* insufficient space for name info */ || NT_SUCCESS(rcNt), false);
+
+            union
+            {
+                 FILE_FS_VOLUME_INFORMATION Info;
+                 uint8_t                    abBuf[sizeof(FILE_FS_VOLUME_INFORMATION) + 4096];
+            } uVol;
+            RT_ZERO(uVol.Info);
+            RTNT_IO_STATUS_BLOCK_REINIT(&Ios);
+            rcNt = NtQueryVolumeInformationFile(auData[i].hFile, &Ios, &uVol, sizeof(uVol), FileFsVolumeInformation);
+            if (NT_SUCCESS(rcNt))
+                auData[i].Vol = uVol.Info;
+            else
+                RT_ZERO(auData[i].Vol);
+        }
+
+        /*
+         * Compare it.
+         */
+        if (   auData[0].All.StandardInformation.Directory
+            == auData[1].All.StandardInformation.Directory)
+        { /* likely */ }
+        else
+            break;
+
+        if (   (auData[0].All.BasicInformation.FileAttributes & (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_DEVICE | FILE_ATTRIBUTE_REPARSE_POINT))
+            == (auData[1].All.BasicInformation.FileAttributes & (FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_DEVICE | FILE_ATTRIBUTE_REPARSE_POINT)))
+        { /* likely */ }
+        else
+            break;
+
+        if (   auData[0].Vol.VolumeSerialNumber
+            == auData[1].Vol.VolumeSerialNumber)
+        { /* likely */ }
+        else
+            break;
+
+        if (   auData[0].All.InternalInformation.IndexNumber.QuadPart
+            == auData[1].All.InternalInformation.IndexNumber.QuadPart)
+        { /* likely */ }
+        else
+            break;
+
+        if (   !NT_SUCCESS(auData[0].rcObjId)
+            || memcmp(&auData[0].ObjId, &auData[1].ObjId, RT_UOFFSETOF(FILE_OBJECTID_INFORMATION, ExtendedInfo)) == 0)
+        {
+            if (   auData[0].All.BasicInformation.CreationTime.QuadPart
+                == auData[1].All.BasicInformation.CreationTime.QuadPart)
+                return true;
+        }
+    }
+
+    return false;
+}
+
+
+/**
+ * If @a hFile is opened in append mode, try return a handle with
+ * FILE_WRITE_DATA permissions.
+ *
+ * @returns Duplicate handle.
+ * @param   hFile               The NT handle to check & duplicate.
+ *
+ * @todo    It would be much easier to implement this by not dropping the
+ *          FILE_WRITE_DATA access and instead have the RTFileWrite APIs
+ *          enforce the appending.  That will require keeping additional
+ *          information along side the handle (instance structure).  However, on
+ *          windows you can grant append permissions w/o giving people access to
+ *          overwrite existing data, so the RTFileOpenEx code would have to deal
+ *          with those kinds of STATUS_ACCESS_DENIED too then.
+ */
+static HANDLE rtFileReOpenAppendOnlyWithFullWriteAccess(HANDLE hFile)
+{
+    OBJECT_BASIC_INFORMATION BasicInfo = {0};
+    ULONG                    cbActual  = 0;
+    NTSTATUS rcNt = NtQueryObject(hFile, ObjectBasicInformation, &BasicInfo, sizeof(BasicInfo), &cbActual);
+    if (NT_SUCCESS(rcNt))
+    {
+        if ((BasicInfo.GrantedAccess & (FILE_APPEND_DATA | FILE_WRITE_DATA)) == FILE_APPEND_DATA)
+        {
+            /*
+             * We cannot use NtDuplicateObject here as it is not possible to
+             * upgrade the access on files, only making it more strict.  So,
+             * query the path and re-open it (we could do by file/object/whatever
+             * id too, but that may not work with all file systems).
+             */
+            for (uint32_t i = 0; i < 16; i++)
+            {
+                UNICODE_STRING  NtName;
+                int rc = RTNtPathFromHandle(&NtName, hFile, 0);
+                AssertRCReturn(rc, INVALID_HANDLE_VALUE);
+
+                HANDLE              hDupFile = RTNT_INVALID_HANDLE_VALUE;
+                IO_STATUS_BLOCK     Ios      = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+                OBJECT_ATTRIBUTES   ObjAttr;
+                InitializeObjectAttributes(&ObjAttr, &NtName, BasicInfo.Attributes & ~OBJ_INHERIT, NULL, NULL);
+
+                rcNt = NtCreateFile(&hDupFile,
+                                    BasicInfo.GrantedAccess | FILE_WRITE_DATA,
+                                    &ObjAttr,
+                                    &Ios,
+                                    NULL /* AllocationSize*/,
+                                    FILE_ATTRIBUTE_NORMAL,
+                                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                    FILE_OPEN,
+                                    FILE_OPEN_FOR_BACKUP_INTENT /*??*/,
+                                    NULL /*EaBuffer*/,
+                                    0 /*EaLength*/);
+                RTUtf16Free(NtName.Buffer);
+                if (NT_SUCCESS(rcNt))
+                {
+                    /*
+                     * Check that we've opened the same file.
+                     */
+                    if (rtFileIsSame(hFile, hDupFile))
+                        return hDupFile;
+                    NtClose(hDupFile);
+                }
+            }
+            AssertFailed();
+        }
+    }
+    return INVALID_HANDLE_VALUE;
+}
+
+#endif
+
+RTR3DECL(int) RTFileSetSize(RTFILE hFile, uint64_t cbSize)
+{
+#if 1
+    HANDLE hNtFile  = (HANDLE)RTFileToNative(hFile);
+    HANDLE hDupFile = INVALID_HANDLE_VALUE;
+    union
+    {
+        FILE_END_OF_FILE_INFORMATION Eof;
+        FILE_ALLOCATION_INFORMATION  Alloc;
+    } uInfo;
+
+    /*
+     * Change the EOF marker.
+     *
+     * HACK ALERT! If the file was opened in RTFILE_O_APPEND mode, we will have
+     *             to re-open it with FILE_WRITE_DATA access to get the job done.
+     *             This how ftruncate on a unixy system would work but not how
+     *             it is done on Windows where appending is a separate permission
+     *             rather than just a write modifier, making this hack totally wrong.
+     */
+    /** @todo The right way to fix this is either to add a RTFileSetSizeEx function
+     *        for specifically requesting the unixy behaviour, or add an additional
+     *        flag to RTFileOpen[Ex] to request the unixy append behaviour there.
+     *        The latter would require saving the open flags in a instance data
+     *        structure, which is a bit of a risky move, though something we should
+     *        do in 6.2 (or later).
+     *
+     *        Note! Because handle interitance, it is not realyan option to
+     *              always use FILE_WRITE_DATA and implement the RTFILE_O_APPEND
+     *              bits in RTFileWrite and friends.  Besides, it's not like
+     *              RTFILE_O_APPEND is so clearly defined anyway - see
+     *              RTFileWriteAt.
+     */
+    IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    uInfo.Eof.EndOfFile.QuadPart = cbSize;
+    NTSTATUS rcNt = NtSetInformationFile(hNtFile, &Ios, &uInfo.Eof, sizeof(uInfo.Eof), FileEndOfFileInformation);
+    if (rcNt == STATUS_ACCESS_DENIED)
+    {
+        hDupFile = rtFileReOpenAppendOnlyWithFullWriteAccess(hNtFile);
+        if (hDupFile != INVALID_HANDLE_VALUE)
+        {
+            hNtFile = hDupFile;
+            uInfo.Eof.EndOfFile.QuadPart = cbSize;
+            rcNt = NtSetInformationFile(hNtFile, &Ios, &uInfo.Eof, sizeof(uInfo.Eof), FileEndOfFileInformation);
+        }
+    }
+
+    if (NT_SUCCESS(rcNt))
+    {
+        /*
+         * Change the allocation.
+         */
+        uInfo.Alloc.AllocationSize.QuadPart = cbSize;
+        rcNt = NtSetInformationFile(hNtFile, &Ios, &uInfo.Eof, sizeof(uInfo.Alloc), FileAllocationInformation);
+    }
+
+    /*
+     * Close the temporary file handle:
+     */
+    if (hDupFile != INVALID_HANDLE_VALUE)
+        NtClose(hDupFile);
+
+    if (RT_SUCCESS(rcNt))
+        return VINF_SUCCESS;
+    return RTErrConvertFromNtStatus(rcNt);
+
+#else /* this version of the code will fail to truncate files when RTFILE_O_APPEND is in effect, which isn't what we want... */
+    /*
+     * Get current file pointer.
+     */
+    int         rc;
+    uint64_t    offCurrent;
+    if (MySetFilePointer(hFile, 0, &offCurrent, FILE_CURRENT))
+    {
+        /*
+         * Set new file pointer.
+         */
+        if (MySetFilePointer(hFile, cbSize, NULL, FILE_BEGIN))
+        {
+            /* set file pointer */
+            if (SetEndOfFile((HANDLE)RTFileToNative(hFile)))
+            {
+                /*
+                 * Restore file pointer and return.
+                 * If the old pointer was beyond the new file end, ignore failure.
+                 */
+                if (    MySetFilePointer(hFile, offCurrent, NULL, FILE_BEGIN)
+                    ||  offCurrent > cbSize)
+                    return VINF_SUCCESS;
+            }
+
+            /*
+             * Failed, try restoring the file pointer.
+             */
+            rc = GetLastError();
+            MySetFilePointer(hFile, offCurrent, NULL, FILE_BEGIN);
+
+            if (rc == ERROR_DISK_FULL)
+                return rtFileWinCheckIfDiskReallyFull(hFile, cbSize);
+        }
+        else
+            rc = GetLastError();
+    }
+    else
+        rc = GetLastError();
+
+    return RTErrConvertFromWin32(rc);
+#endif
+}
+
+
+RTR3DECL(int)  RTFileQuerySize(RTFILE hFile, uint64_t *pcbSize)
+{
+    /*
+     * GetFileSize works for most handles.
+     */
+    ULARGE_INTEGER  Size;
+    Size.LowPart = GetFileSize((HANDLE)RTFileToNative(hFile), &Size.HighPart);
+    if (Size.LowPart != INVALID_FILE_SIZE)
+    {
+        *pcbSize = Size.QuadPart;
+        return VINF_SUCCESS;
+    }
+    int rc = RTErrConvertFromWin32(GetLastError());
+
+    /*
+     * Could it be a volume or a disk?
+     */
+    DISK_GEOMETRY   DriveGeo;
+    DWORD           cbDriveGeo;
+    if (DeviceIoControl((HANDLE)RTFileToNative(hFile),
+                        IOCTL_DISK_GET_DRIVE_GEOMETRY, NULL, 0,
+                        &DriveGeo, sizeof(DriveGeo), &cbDriveGeo, NULL))
+    {
+        if (   DriveGeo.MediaType == FixedMedia
+            || DriveGeo.MediaType == RemovableMedia)
+        {
+            *pcbSize = DriveGeo.Cylinders.QuadPart
+                     * DriveGeo.TracksPerCylinder
+                     * DriveGeo.SectorsPerTrack
+                     * DriveGeo.BytesPerSector;
+
+            GET_LENGTH_INFORMATION  DiskLenInfo;
+            DWORD                   Ignored;
+            if (DeviceIoControl((HANDLE)RTFileToNative(hFile),
+                                IOCTL_DISK_GET_LENGTH_INFO, NULL, 0,
+                                &DiskLenInfo, sizeof(DiskLenInfo), &Ignored, (LPOVERLAPPED)NULL))
+            {
+                /* IOCTL_DISK_GET_LENGTH_INFO is supported -- override cbSize. */
+                *pcbSize = DiskLenInfo.Length.QuadPart;
+            }
+            return VINF_SUCCESS;
+        }
+    }
+
+    /*
+     * Return the GetFileSize result if not a volume/disk.
+     */
+    return rc;
+}
+
+
+RTR3DECL(int) RTFileQueryMaxSizeEx(RTFILE hFile, PRTFOFF pcbMax)
+{
+    /** @todo r=bird:
+     * We might have to make this code OS version specific... In the worse
+     * case, we'll have to try GetVolumeInformationByHandle on vista and fall
+     * back on NtQueryVolumeInformationFile(,,,, FileFsAttributeInformation)
+     * else where, and check for known file system names. (For LAN shares we'll
+     * have to figure out the remote file system.) */
+    RT_NOREF_PV(hFile); RT_NOREF_PV(pcbMax);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTR3DECL(bool) RTFileIsValid(RTFILE hFile)
+{
+    if (hFile != NIL_RTFILE)
+    {
+        DWORD dwType = GetFileType((HANDLE)RTFileToNative(hFile));
+        switch (dwType)
+        {
+            case FILE_TYPE_CHAR:
+            case FILE_TYPE_DISK:
+            case FILE_TYPE_PIPE:
+            case FILE_TYPE_REMOTE:
+                return true;
+
+            case FILE_TYPE_UNKNOWN:
+                if (GetLastError() == NO_ERROR)
+                    return true;
+                break;
+
+            default:
+                break;
+        }
+    }
+    return false;
+}
+
+
+#define LOW_DWORD(u64) ((DWORD)u64)
+#define HIGH_DWORD(u64) (((DWORD *)&u64)[1])
+
+RTR3DECL(int)  RTFileLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /* Prepare flags. */
+    Assert(RTFILE_LOCK_WRITE);
+    DWORD dwFlags = (fLock & RTFILE_LOCK_WRITE) ? LOCKFILE_EXCLUSIVE_LOCK : 0;
+    Assert(RTFILE_LOCK_WAIT);
+    if (!(fLock & RTFILE_LOCK_WAIT))
+        dwFlags |= LOCKFILE_FAIL_IMMEDIATELY;
+
+    /* Windows structure. */
+    OVERLAPPED Overlapped;
+    memset(&Overlapped, 0, sizeof(Overlapped));
+    Overlapped.Offset = LOW_DWORD(offLock);
+    Overlapped.OffsetHigh = HIGH_DWORD(offLock);
+
+    /* Note: according to Microsoft, LockFileEx API call is available starting from NT 3.5 */
+    if (LockFileEx((HANDLE)RTFileToNative(hFile), dwFlags, 0, LOW_DWORD(cbLock), HIGH_DWORD(cbLock), &Overlapped))
+        return VINF_SUCCESS;
+
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTR3DECL(int)  RTFileChangeLock(RTFILE hFile, unsigned fLock, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    /* Check arguments. */
+    if (fLock & ~RTFILE_LOCK_MASK)
+    {
+        AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /* Remove old lock. */
+    int rc = RTFileUnlock(hFile, offLock, cbLock);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /* Set new lock. */
+    rc = RTFileLock(hFile, fLock, offLock, cbLock);
+    if (RT_SUCCESS(rc))
+        return rc;
+
+    /* Try to restore old lock. */
+    unsigned fLockOld = (fLock & RTFILE_LOCK_WRITE) ? fLock & ~RTFILE_LOCK_WRITE : fLock | RTFILE_LOCK_WRITE;
+    rc = RTFileLock(hFile, fLockOld, offLock, cbLock);
+    if (RT_SUCCESS(rc))
+        return VERR_FILE_LOCK_VIOLATION;
+    else
+        return VERR_FILE_LOCK_LOST;
+}
+
+
+RTR3DECL(int)  RTFileUnlock(RTFILE hFile, int64_t offLock, uint64_t cbLock)
+{
+    Assert(offLock >= 0);
+
+    if (UnlockFile((HANDLE)RTFileToNative(hFile),
+                   LOW_DWORD(offLock), HIGH_DWORD(offLock),
+                   LOW_DWORD(cbLock), HIGH_DWORD(cbLock)))
+        return VINF_SUCCESS;
+
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+
+RTR3DECL(int) RTFileQueryInfo(RTFILE hFile, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    /*
+     * Validate input.
+     */
+    if (hFile == NIL_RTFILE)
+    {
+        AssertMsgFailed(("Invalid hFile=%RTfile\n", hFile));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (!pObjInfo)
+    {
+        AssertMsgFailed(("Invalid pObjInfo=%p\n", pObjInfo));
+        return VERR_INVALID_PARAMETER;
+    }
+    if (    enmAdditionalAttribs < RTFSOBJATTRADD_NOTHING
+        ||  enmAdditionalAttribs > RTFSOBJATTRADD_LAST)
+    {
+        AssertMsgFailed(("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs));
+        return VERR_INVALID_PARAMETER;
+    }
+
+    /*
+     * Query file info.
+     */
+    HANDLE hHandle = (HANDLE)RTFileToNative(hFile);
+#if 1
+    uint64_t auBuf[168 / sizeof(uint64_t)]; /* Missing FILE_ALL_INFORMATION here. */
+    int rc = rtPathNtQueryInfoFromHandle(hFile, auBuf, sizeof(auBuf), pObjInfo, enmAdditionalAttribs, NULL, 0);
+    if (RT_SUCCESS(rc))
+        return rc;
+
+    /*
+     * Console I/O handles make trouble here.  On older windows versions they
+     * end up with ERROR_INVALID_HANDLE when handed to the above API, while on
+     * more recent ones they cause different errors to appear.
+     *
+     * Thus, we must ignore the latter and doubly verify invalid handle claims.
+     * We use the undocumented VerifyConsoleIoHandle to do this, falling back on
+     * GetFileType should it not be there.
+     */
+    if (   rc == VERR_INVALID_HANDLE
+        || rc == VERR_ACCESS_DENIED
+        || rc == VERR_UNEXPECTED_FS_OBJ_TYPE)
+    {
+        static PFNVERIFYCONSOLEIOHANDLE s_pfnVerifyConsoleIoHandle = NULL;
+        static bool volatile            s_fInitialized = false;
+        PFNVERIFYCONSOLEIOHANDLE        pfnVerifyConsoleIoHandle;
+        if (s_fInitialized)
+            pfnVerifyConsoleIoHandle = s_pfnVerifyConsoleIoHandle;
+        else
+        {
+            pfnVerifyConsoleIoHandle = (PFNVERIFYCONSOLEIOHANDLE)RTLdrGetSystemSymbol("kernel32.dll", "VerifyConsoleIoHandle");
+            ASMAtomicWriteBool(&s_fInitialized, true);
+        }
+        if (   pfnVerifyConsoleIoHandle
+            ? !pfnVerifyConsoleIoHandle(hHandle)
+            : GetFileType(hHandle) == FILE_TYPE_UNKNOWN && GetLastError() != NO_ERROR)
+            return VERR_INVALID_HANDLE;
+    }
+    /*
+     * On Windows 10 and (hopefully) 8.1 we get ERROR_INVALID_FUNCTION with console
+     * I/O handles and null device handles.  We must ignore these just like the
+     * above invalid handle error.
+     */
+    else if (rc != VERR_INVALID_FUNCTION && rc != VERR_IO_BAD_COMMAND)
+        return rc;
+
+    RT_ZERO(*pObjInfo);
+    pObjInfo->Attr.enmAdditional = enmAdditionalAttribs;
+    pObjInfo->Attr.fMode = rtFsModeFromDos(RTFS_DOS_NT_DEVICE, "", 0, 0, 0);
+    return VINF_SUCCESS;
+#else
+
+    BY_HANDLE_FILE_INFORMATION Data;
+    if (!GetFileInformationByHandle(hHandle, &Data))
+    {
+        /*
+         * Console I/O handles make trouble here.  On older windows versions they
+         * end up with ERROR_INVALID_HANDLE when handed to the above API, while on
+         * more recent ones they cause different errors to appear.
+         *
+         * Thus, we must ignore the latter and doubly verify invalid handle claims.
+         * We use the undocumented VerifyConsoleIoHandle to do this, falling back on
+         * GetFileType should it not be there.
+         */
+        DWORD dwErr = GetLastError();
+        if (dwErr == ERROR_INVALID_HANDLE)
+        {
+            static PFNVERIFYCONSOLEIOHANDLE s_pfnVerifyConsoleIoHandle = NULL;
+            static bool volatile            s_fInitialized = false;
+            PFNVERIFYCONSOLEIOHANDLE        pfnVerifyConsoleIoHandle;
+            if (s_fInitialized)
+                pfnVerifyConsoleIoHandle = s_pfnVerifyConsoleIoHandle;
+            else
+            {
+                pfnVerifyConsoleIoHandle = (PFNVERIFYCONSOLEIOHANDLE)RTLdrGetSystemSymbol("kernel32.dll", "VerifyConsoleIoHandle");
+                ASMAtomicWriteBool(&s_fInitialized, true);
+            }
+            if (   pfnVerifyConsoleIoHandle
+                ? !pfnVerifyConsoleIoHandle(hHandle)
+                : GetFileType(hHandle) == FILE_TYPE_UNKNOWN && GetLastError() != NO_ERROR)
+                return VERR_INVALID_HANDLE;
+        }
+        /*
+         * On Windows 10 and (hopefully) 8.1 we get ERROR_INVALID_FUNCTION with console I/O
+         * handles.  We must ignore these just like the above invalid handle error.
+         */
+        else if (dwErr != ERROR_INVALID_FUNCTION)
+            return RTErrConvertFromWin32(dwErr);
+
+        RT_ZERO(Data);
+        Data.dwFileAttributes = RTFS_DOS_NT_DEVICE;
+    }
+
+    /*
+     * Setup the returned data.
+     */
+    pObjInfo->cbObject    = ((uint64_t)Data.nFileSizeHigh << 32)
+                          |  (uint64_t)Data.nFileSizeLow;
+    pObjInfo->cbAllocated = pObjInfo->cbObject;
+
+    Assert(sizeof(uint64_t) == sizeof(Data.ftCreationTime));
+    RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         *(uint64_t *)&Data.ftCreationTime);
+    RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        *(uint64_t *)&Data.ftLastAccessTime);
+    RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  *(uint64_t *)&Data.ftLastWriteTime);
+    pObjInfo->ChangeTime  = pObjInfo->ModificationTime;
+
+    pObjInfo->Attr.fMode  = rtFsModeFromDos((Data.dwFileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT, "", 0,
+                                            RTFSMODE_SYMLINK_REPARSE_TAG /* (symlink or not, doesn't usually matter here) */);
+
+    /*
+     * Requested attributes (we cannot provide anything actually).
+     */
+    switch (enmAdditionalAttribs)
+    {
+        case RTFSOBJATTRADD_NOTHING:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_NOTHING;
+            break;
+
+        case RTFSOBJATTRADD_UNIX:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+            pObjInfo->Attr.u.Unix.uid             = ~0U;
+            pObjInfo->Attr.u.Unix.gid             = ~0U;
+            pObjInfo->Attr.u.Unix.cHardlinks      = Data.nNumberOfLinks ? Data.nNumberOfLinks : 1;
+            pObjInfo->Attr.u.Unix.INodeIdDevice   = Data.dwVolumeSerialNumber;
+            pObjInfo->Attr.u.Unix.INodeId         = RT_MAKE_U64(Data.nFileIndexLow, Data.nFileIndexHigh);
+            pObjInfo->Attr.u.Unix.fFlags          = 0;
+            pObjInfo->Attr.u.Unix.GenerationId    = 0;
+            pObjInfo->Attr.u.Unix.Device          = 0;
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+            pObjInfo->Attr.u.UnixOwner.uid        = ~0U;
+            pObjInfo->Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+            pObjInfo->Attr.u.UnixGroup.gid        = ~0U;
+            pObjInfo->Attr.u.UnixGroup.szName[0]  = '\0';
+            break;
+
+        case RTFSOBJATTRADD_EASIZE:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+            pObjInfo->Attr.u.EASize.cb            = 0;
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    return VINF_SUCCESS;
+#endif
+}
+
+
+RTR3DECL(int) RTFileSetTimes(RTFILE hFile, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                             PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
+{
+    RT_NOREF_PV(pChangeTime); /* Not exposed thru the windows API we're using. */
+
+    if (!pAccessTime && !pModificationTime && !pBirthTime)
+        return VINF_SUCCESS;    /* NOP */
+
+    FILETIME    CreationTimeFT;
+    PFILETIME   pCreationTimeFT = NULL;
+    if (pBirthTime)
+        pCreationTimeFT = RTTimeSpecGetNtFileTime(pBirthTime, &CreationTimeFT);
+
+    FILETIME    LastAccessTimeFT;
+    PFILETIME   pLastAccessTimeFT = NULL;
+    if (pAccessTime)
+        pLastAccessTimeFT = RTTimeSpecGetNtFileTime(pAccessTime, &LastAccessTimeFT);
+
+    FILETIME    LastWriteTimeFT;
+    PFILETIME   pLastWriteTimeFT = NULL;
+    if (pModificationTime)
+        pLastWriteTimeFT = RTTimeSpecGetNtFileTime(pModificationTime, &LastWriteTimeFT);
+
+    int rc = VINF_SUCCESS;
+    if (!SetFileTime((HANDLE)RTFileToNative(hFile), pCreationTimeFT, pLastAccessTimeFT, pLastWriteTimeFT))
+    {
+        DWORD Err = GetLastError();
+        rc = RTErrConvertFromWin32(Err);
+        Log(("RTFileSetTimes(%RTfile, %p, %p, %p, %p): SetFileTime failed with lasterr %d (%Rrc)\n",
+             hFile, pAccessTime, pModificationTime, pChangeTime, pBirthTime, Err, rc));
+    }
+    return rc;
+}
+
+
+#if 0 /* RTFileSetMode is implemented by RTFileSetMode-r3-nt.cpp */
+/* This comes from a source file with a different set of system headers (DDK)
+ * so it can't be declared in a common header, like internal/file.h.
+ */
+extern int rtFileNativeSetAttributes(HANDLE FileHandle, ULONG FileAttributes);
+
+
+RTR3DECL(int) RTFileSetMode(RTFILE hFile, RTFMODE fMode)
+{
+    /*
+     * Normalize the mode and call the API.
+     */
+    fMode = rtFsModeNormalize(fMode, NULL, 0);
+    if (!rtFsModeIsValid(fMode))
+        return VERR_INVALID_PARAMETER;
+
+    ULONG FileAttributes = (fMode & RTFS_DOS_MASK) >> RTFS_DOS_SHIFT;
+    int Err = rtFileNativeSetAttributes((HANDLE)hFile, FileAttributes);
+    if (Err != ERROR_SUCCESS)
+    {
+        int rc = RTErrConvertFromWin32(Err);
+        Log(("RTFileSetMode(%RTfile, %RTfmode): rtFileNativeSetAttributes (0x%08X) failed with err %d (%Rrc)\n",
+             hFile, fMode, FileAttributes, Err, rc));
+        return rc;
+    }
+    return VINF_SUCCESS;
+}
+#endif
+
+
+/* RTFileQueryFsSizes is implemented by ../nt/RTFileQueryFsSizes-nt.cpp */
+
+
+RTR3DECL(int)  RTFileDelete(const char *pszFilename)
+{
+    PRTUTF16 pwszFilename;
+    int rc = RTPathWinFromUtf8(&pwszFilename, pszFilename, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        if (!DeleteFileW(pwszFilename))
+            rc = RTErrConvertFromWin32(GetLastError());
+        RTPathWinFree(pwszFilename);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFileRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Hand it on to the worker.
+     */
+    int rc = rtPathWin32MoveRename(pszSrc, pszDst,
+                                   fRename & RTPATHRENAME_FLAGS_REPLACE ? MOVEFILE_REPLACE_EXISTING : 0,
+                                   RTFS_TYPE_FILE);
+
+    LogFlow(("RTFileMove(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n",
+             pszSrc, pszSrc, pszDst, pszDst, fRename, rc));
+    return rc;
+
+}
+
+
+RTDECL(int) RTFileMove(const char *pszSrc, const char *pszDst, unsigned fMove)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(!(fMove & ~RTFILEMOVE_FLAGS_REPLACE), ("%#x\n", fMove), VERR_INVALID_PARAMETER);
+
+    /*
+     * Hand it on to the worker.
+     */
+    int rc = rtPathWin32MoveRename(pszSrc, pszDst,
+                                   fMove & RTFILEMOVE_FLAGS_REPLACE
+                                   ? MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING
+                                   : MOVEFILE_COPY_ALLOWED,
+                                   RTFS_TYPE_FILE);
+
+    LogFlow(("RTFileMove(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n",
+             pszSrc, pszSrc, pszDst, pszDst, fMove, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/fs-win.cpp b/src/VBox/Runtime/r3/win/fs-win.cpp
new file mode 100644
index 00000000..4210ffed
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/fs-win.cpp
@@ -0,0 +1,440 @@
+/* $Id: fs-win.cpp $ */
+/** @file
+ * IPRT - File System, Win32.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FS
+#include <iprt/win/windows.h>
+
+#include <iprt/fs.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/param.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include "internal/fs.h"
+
+/* from ntdef.h */
+typedef LONG NTSTATUS;
+
+/* from ntddk.h */
+typedef struct _IO_STATUS_BLOCK {
+    union {
+        NTSTATUS Status;
+        PVOID Pointer;
+    };
+    ULONG_PTR Information;
+} IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
+
+typedef enum _FSINFOCLASS {
+    FileFsAttributeInformation = 5,
+} FS_INFORMATION_CLASS, *PFS_INFORMATION_CLASS;
+
+/* from ntifs.h */
+
+typedef struct _FILE_FS_ATTRIBUTE_INFORMATION {
+    ULONG FileSystemAttributes;
+    LONG MaximumComponentNameLength;
+    ULONG FileSystemNameLength;
+    WCHAR FileSystemName[1];
+} FILE_FS_ATTRIBUTE_INFORMATION, *PFILE_FS_ATTRIBUTE_INFORMATION;
+
+extern "C" NTSTATUS NTAPI NtQueryVolumeInformationFile(HANDLE, PIO_STATUS_BLOCK, PVOID, ULONG, FS_INFORMATION_CLASS);
+
+/**
+ * Checks quickly if this is an correct root specification.
+ * Root specs ends with a slash of some kind.
+ *
+ * @returns indicator.
+ * @param   pszFsPath       Path to check.
+ */
+static bool rtFsIsRoot(const char *pszFsPath)
+{
+    /*
+     * UNC has exactly two slashes..
+     *
+     * Anything else starting with slashe(s) requires
+     * expansion and will have to take the long road.
+     */
+    if (RTPATH_IS_SLASH(pszFsPath[0]))
+    {
+        if (    !RTPATH_IS_SLASH(pszFsPath[1])
+            ||  RTPATH_IS_SLASH(pszFsPath[2]))
+            return false;
+
+        /* end of machine name */
+        const char *pszSlash = strpbrk(pszFsPath + 2, "\\/");
+        if (!pszSlash)
+            return false;
+
+        /* end of service name. */
+        pszSlash = strpbrk(pszSlash + 1, "\\/");
+        if (!pszSlash)
+            return false;
+
+        return pszSlash[1] == '\0';
+    }
+
+    /*
+     * Ok the other alternative is driver letter.
+     */
+    return  pszFsPath[0] >= 'A' && pszFsPath[0] <= 'Z'
+        &&  pszFsPath[1] == ':'
+        &&  RTPATH_IS_SLASH(pszFsPath[2])
+        && !pszFsPath[3];
+}
+
+
+
+/**
+ * Finds the root of the specified volume.
+ *
+ * @returns iprt status code.
+ * @param   pszFsPath       Path within the filesystem. Verified as one byte or more.
+ * @param   ppwszFsRoot     Where to store the returned string. Free with rtFsFreeRoot(),
+ */
+static int rtFsGetRoot(const char *pszFsPath, PRTUTF16 *ppwszFsRoot)
+{
+    /*
+     * Do straight forward stuff first,
+     */
+    if (rtFsIsRoot(pszFsPath))
+        return RTStrToUtf16(pszFsPath, ppwszFsRoot);
+
+    /*
+     * Expand and add slash (if required).
+     */
+    char szFullPath[RTPATH_MAX];
+    int rc = RTPathAbs(pszFsPath, szFullPath, sizeof(szFullPath));
+    if (RT_FAILURE(rc))
+        return rc;
+    size_t cb = strlen(szFullPath);
+    if (!RTPATH_IS_SLASH(szFullPath[cb - 1]))
+    {
+        AssertReturn(cb + 1 < RTPATH_MAX, VERR_FILENAME_TOO_LONG);
+        szFullPath[cb] = '\\';
+        szFullPath[++cb] = '\0';
+    }
+
+    /*
+     * Convert the path.
+     */
+    rc = RTStrToUtf16(szFullPath, ppwszFsRoot);
+    if (RT_FAILURE(rc))
+        return rc == VERR_BUFFER_OVERFLOW ? VERR_FILENAME_TOO_LONG : rc;
+
+    /*
+     * Walk the path until our proper API is happy or there is no more path left.
+     */
+    PRTUTF16 pwszStart = *ppwszFsRoot;
+    if (!GetVolumeInformationW(pwszStart, NULL, 0, NULL, NULL, 0, NULL, 0))
+    {
+        PRTUTF16 pwszEnd = pwszStart + RTUtf16Len(pwszStart);
+        PRTUTF16 pwszMin = pwszStart + 2;
+        do
+        {
+            /* Strip off the last path component. */
+            while (pwszEnd-- > pwszMin)
+                if (RTPATH_IS_SLASH(*pwszEnd))
+                    break;
+            AssertReturn(pwszEnd >= pwszMin, VERR_INTERNAL_ERROR); /* leaks, but that's irrelevant for an internal error. */
+            pwszEnd[1] = '\0';
+        } while (!GetVolumeInformationW(pwszStart, NULL, 0, NULL, NULL, 0, NULL, 0));
+    }
+
+    return VINF_SUCCESS;
+}
+
+/**
+ * Frees string returned by rtFsGetRoot().
+ */
+static void rtFsFreeRoot(PRTUTF16 pwszFsRoot)
+{
+    RTUtf16Free(pwszFsRoot);
+}
+
+
+RTR3DECL(int) RTFsQuerySizes(const char *pszFsPath, RTFOFF *pcbTotal, RTFOFF *pcbFree,
+                             uint32_t *pcbBlock, uint32_t *pcbSector)
+{
+    /*
+     * Validate & get valid root path.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+    PRTUTF16 pwszFsRoot;
+    int rc = rtFsGetRoot(pszFsPath, &pwszFsRoot);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Free and total.
+     */
+    if (pcbTotal || pcbFree)
+    {
+        ULARGE_INTEGER cbTotal;
+        ULARGE_INTEGER cbFree;
+        if (GetDiskFreeSpaceExW(pwszFsRoot, &cbFree, &cbTotal, NULL))
+        {
+            if (pcbTotal)
+                *pcbTotal = cbTotal.QuadPart;
+            if (pcbFree)
+                *pcbFree  = cbFree.QuadPart;
+        }
+        else
+        {
+            DWORD Err = GetLastError();
+            rc = RTErrConvertFromWin32(Err);
+            Log(("RTFsQuerySizes(%s,): GetDiskFreeSpaceEx failed with lasterr %d (%Rrc)\n",
+                 pszFsPath, Err, rc));
+        }
+    }
+
+    /*
+     * Block and sector size.
+     */
+    if (    RT_SUCCESS(rc)
+        &&  (pcbBlock || pcbSector))
+    {
+        DWORD dwDummy1, dwDummy2;
+        DWORD cbSector;
+        DWORD cSectorsPerCluster;
+        if (GetDiskFreeSpaceW(pwszFsRoot, &cSectorsPerCluster, &cbSector, &dwDummy1, &dwDummy2))
+        {
+            if (pcbBlock)
+                *pcbBlock = cbSector * cSectorsPerCluster;
+            if (pcbSector)
+                *pcbSector = cbSector;
+        }
+        else
+        {
+            DWORD Err = GetLastError();
+            rc = RTErrConvertFromWin32(Err);
+            Log(("RTFsQuerySizes(%s,): GetDiskFreeSpace failed with lasterr %d (%Rrc)\n",
+                 pszFsPath, Err, rc));
+        }
+    }
+
+    rtFsFreeRoot(pwszFsRoot);
+    return rc;
+}
+
+
+/**
+ * Query the serial number of a filesystem.
+ *
+ * @returns iprt status code.
+ * @param   pszFsPath       Path within the mounted filesystem.
+ * @param   pu32Serial      Where to store the serial number.
+ */
+RTR3DECL(int) RTFsQuerySerial(const char *pszFsPath, uint32_t *pu32Serial)
+{
+    /*
+     * Validate & get valid root path.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pu32Serial, VERR_INVALID_POINTER);
+    PRTUTF16 pwszFsRoot;
+    int rc = rtFsGetRoot(pszFsPath, &pwszFsRoot);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Do work.
+     */
+    DWORD   dwMaxName;
+    DWORD   dwFlags;
+    DWORD   dwSerial;
+    if (GetVolumeInformationW(pwszFsRoot, NULL, 0, &dwSerial, &dwMaxName, &dwFlags, NULL, 0))
+        *pu32Serial = dwSerial;
+    else
+    {
+        DWORD Err = GetLastError();
+        rc = RTErrConvertFromWin32(Err);
+        Log(("RTFsQuerySizes(%s,): GetDiskFreeSpaceEx failed with lasterr %d (%Rrc)\n",
+             pszFsPath, Err, rc));
+    }
+
+    rtFsFreeRoot(pwszFsRoot);
+    return rc;
+}
+
+
+/**
+ * Query the properties of a mounted filesystem.
+ *
+ * @returns iprt status code.
+ * @param   pszFsPath       Path within the mounted filesystem.
+ * @param   pProperties     Where to store the properties.
+ */
+RTR3DECL(int) RTFsQueryProperties(const char *pszFsPath, PRTFSPROPERTIES pProperties)
+{
+    /*
+     * Validate & get valid root path.
+     */
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath != '\0', VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pProperties, VERR_INVALID_POINTER);
+    PRTUTF16 pwszFsRoot;
+    int rc = rtFsGetRoot(pszFsPath, &pwszFsRoot);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * Do work.
+     */
+    DWORD   dwMaxName;
+    DWORD   dwFlags;
+    DWORD   dwSerial;
+    if (GetVolumeInformationW(pwszFsRoot, NULL, 0, &dwSerial, &dwMaxName, &dwFlags, NULL, 0))
+    {
+        memset(pProperties, 0, sizeof(*pProperties));
+        pProperties->cbMaxComponent   = dwMaxName;
+        pProperties->fFileCompression = !!(dwFlags & FILE_FILE_COMPRESSION);
+        pProperties->fCompressed      = !!(dwFlags & FILE_VOLUME_IS_COMPRESSED);
+        pProperties->fReadOnly        = !!(dwFlags & FILE_READ_ONLY_VOLUME);
+        pProperties->fSupportsUnicode = !!(dwFlags & FILE_UNICODE_ON_DISK);
+        pProperties->fCaseSensitive   = false;    /* win32 is case preserving only */
+        /** @todo r=bird: What about FILE_CASE_SENSITIVE_SEARCH ?  Is this set for NTFS
+         *        as well perchance?  If so, better mention it instead of just setting
+         *        fCaseSensitive to false. */
+        pProperties->fRemote          = false;    /* no idea yet */
+    }
+    else
+    {
+        DWORD Err = GetLastError();
+        rc = RTErrConvertFromWin32(Err);
+        Log(("RTFsQuerySizes(%s,): GetVolumeInformation failed with lasterr %d (%Rrc)\n",
+             pszFsPath, Err, rc));
+    }
+
+    rtFsFreeRoot(pwszFsRoot);
+    return rc;
+}
+
+
+RTR3DECL(bool) RTFsIsCaseSensitive(const char *pszFsPath)
+{
+    return false;
+}
+
+
+/**
+ * Internal helper for comparing a WCHAR string with a char string.
+ *
+ * @returns @c true if equal, @c false if not.
+ * @param   pwsz1               The first string.
+ * @param   cch1                The length of the first string, in bytes.
+ * @param   psz2                The second string.
+ * @param   cch2                The length of the second string.
+ */
+static bool rtFsWinAreEqual(WCHAR const *pwsz1, size_t cch1, const char *psz2, size_t cch2)
+{
+    if (cch1 != cch2 * 2)
+        return false;
+    while (cch2-- > 0)
+    {
+        unsigned ch1 = *pwsz1++;
+        unsigned ch2 = (unsigned char)*psz2++;
+        if (ch1 != ch2)
+            return false;
+    }
+    return true;
+}
+
+
+RTR3DECL(int) RTFsQueryType(const char *pszFsPath, PRTFSTYPE penmType)
+{
+    *penmType = RTFSTYPE_UNKNOWN;
+
+    AssertPtrReturn(pszFsPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszFsPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the path and try open it.
+     */
+    PRTUTF16 pwszFsPath;
+    int rc = RTPathWinFromUtf8(&pwszFsPath, pszFsPath, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE hFile = CreateFileW(pwszFsPath,
+                                   GENERIC_READ,
+                                   FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                   NULL,
+                                   OPEN_EXISTING,
+                                   FILE_FLAG_BACKUP_SEMANTICS,
+                                   NULL);
+        if (hFile != INVALID_HANDLE_VALUE)
+        {
+            /*
+             * Use the NT api directly to get the file system name.
+             */
+            char            abBuf[8192];
+            IO_STATUS_BLOCK Ios;
+            NTSTATUS        rcNt = NtQueryVolumeInformationFile(hFile, &Ios,
+                                                                abBuf, sizeof(abBuf),
+                                                                FileFsAttributeInformation);
+            if (rcNt >= 0)
+            {
+                PFILE_FS_ATTRIBUTE_INFORMATION pFsAttrInfo = (PFILE_FS_ATTRIBUTE_INFORMATION)abBuf;
+#define IS_FS(szName) \
+    rtFsWinAreEqual(pFsAttrInfo->FileSystemName, pFsAttrInfo->FileSystemNameLength, szName, sizeof(szName) - 1)
+                if (IS_FS("NTFS"))
+                    *penmType = RTFSTYPE_NTFS;
+                else if (IS_FS("FAT"))
+                    *penmType = RTFSTYPE_FAT;
+                else if (IS_FS("FAT32"))
+                    *penmType = RTFSTYPE_FAT;
+                else if (IS_FS("EXFAT"))
+                    *penmType = RTFSTYPE_EXFAT;
+                else if (IS_FS("VBoxSharedFolderFS"))
+                    *penmType = RTFSTYPE_VBOXSHF;
+#undef IS_FS
+            }
+            else
+                rc = RTErrConvertFromNtStatus(rcNt);
+            CloseHandle(hFile);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        RTPathWinFree(pwszFsPath);
+    }
+    return rc;
+}
diff --git a/src/VBox/Runtime/r3/win/init-win.cpp b/src/VBox/Runtime/r3/win/init-win.cpp
new file mode 100644
index 00000000..92cd2665
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/init-win.cpp
@@ -0,0 +1,919 @@
+/* $Id: init-win.cpp $ */
+/** @file
+ * IPRT - Init Ring-3, Windows Specific Code.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/nt/nt-and-windows.h>
+#ifndef LOAD_LIBRARY_SEARCH_APPLICATION_DIR
+# define LOAD_LIBRARY_SEARCH_APPLICATION_DIR    0x200
+# define LOAD_LIBRARY_SEARCH_SYSTEM32           0x800
+#endif
+
+#include "internal-r3-win.h"
+#include <iprt/initterm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/param.h>
+#include <iprt/process.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include "../init.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef VOID (WINAPI *PFNGETCURRENTTHREADSTACKLIMITS)(PULONG_PTR puLow, PULONG_PTR puHigh);
+typedef LPTOP_LEVEL_EXCEPTION_FILTER (WINAPI * PFNSETUNHANDLEDEXCEPTIONFILTER)(LPTOP_LEVEL_EXCEPTION_FILTER);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Windows DLL loader protection level. */
+DECL_HIDDEN_DATA(RTR3WINLDRPROT)      g_enmWinLdrProt = RTR3WINLDRPROT_NONE;
+/** Our simplified windows version.    */
+DECL_HIDDEN_DATA(RTWINOSTYPE)         g_enmWinVer = kRTWinOSType_UNKNOWN;
+/** Extended windows version information. */
+DECL_HIDDEN_DATA(OSVERSIONINFOEXW)    g_WinOsInfoEx;
+
+/** The native kernel32.dll handle. */
+DECL_HIDDEN_DATA(HMODULE)                       g_hModKernel32 = NULL;
+/** GetSystemWindowsDirectoryW or GetWindowsDirectoryW (NT4). */
+DECL_HIDDEN_DATA(PFNGETWINSYSDIR)               g_pfnGetSystemWindowsDirectoryW = NULL;
+/** The GetCurrentThreadStackLimits API. */
+static PFNGETCURRENTTHREADSTACKLIMITS           g_pfnGetCurrentThreadStackLimits = NULL;
+/** The previous unhandled exception filter. */
+static LPTOP_LEVEL_EXCEPTION_FILTER             g_pfnUnhandledXcptFilter = NULL;
+/** SystemTimeToTzSpecificLocalTime. */
+DECL_HIDDEN_DATA(decltype(SystemTimeToTzSpecificLocalTime) *)   g_pfnSystemTimeToTzSpecificLocalTime = NULL;
+/** CreateWaitableTimerEx . */
+DECL_HIDDEN_DATA(PFNCREATEWAITABLETIMEREX)                      g_pfnCreateWaitableTimerExW = NULL;
+DECL_HIDDEN_DATA(decltype(GetHandleInformation) *)              g_pfnGetHandleInformation = NULL;
+DECL_HIDDEN_DATA(decltype(SetHandleInformation) *)              g_pfnSetHandleInformation = NULL;
+DECL_HIDDEN_DATA(decltype(IsDebuggerPresent) *)                 g_pfnIsDebuggerPresent = NULL;
+DECL_HIDDEN_DATA(decltype(GetSystemTimeAsFileTime) *)           g_pfnGetSystemTimeAsFileTime = NULL;
+DECL_HIDDEN_DATA(decltype(GetProcessAffinityMask) *)            g_pfnGetProcessAffinityMask = NULL;
+DECL_HIDDEN_DATA(decltype(SetThreadAffinityMask) *)             g_pfnSetThreadAffinityMask = NULL;
+DECL_HIDDEN_DATA(decltype(CreateIoCompletionPort) *)            g_pfnCreateIoCompletionPort = NULL;
+DECL_HIDDEN_DATA(decltype(GetQueuedCompletionStatus) *)         g_pfnGetQueuedCompletionStatus = NULL;
+DECL_HIDDEN_DATA(decltype(PostQueuedCompletionStatus) *)        g_pfnPostQueuedCompletionStatus = NULL;
+DECL_HIDDEN_DATA(decltype(IsProcessorFeaturePresent) *)         g_pfnIsProcessorFeaturePresent = NULL;
+DECL_HIDDEN_DATA(decltype(SetUnhandledExceptionFilter) *)       g_pfnSetUnhandledExceptionFilter = NULL;
+DECL_HIDDEN_DATA(decltype(UnhandledExceptionFilter) *)          g_pfnUnhandledExceptionFilter = NULL;
+
+/** The native ntdll.dll handle. */
+DECL_HIDDEN_DATA(HMODULE)                       g_hModNtDll = NULL;
+/** NtQueryFullAttributesFile   */
+DECL_HIDDEN_DATA(PFNNTQUERYFULLATTRIBUTESFILE)  g_pfnNtQueryFullAttributesFile = NULL;
+/** NtDuplicateToken (NT 3.51). */
+DECL_HIDDEN_DATA(PFNNTDUPLICATETOKEN)           g_pfnNtDuplicateToken = NULL;
+/** NtAlertThread (NT 3.51). */
+DECL_HIDDEN_DATA(decltype(NtAlertThread) *)     g_pfnNtAlertThread = NULL;
+
+/** Either ws2_32.dll (NT4+) or wsock32.dll (NT3.x). */
+DECL_HIDDEN_DATA(HMODULE)                       g_hModWinSock = NULL;
+/** Set if we're dealing with old winsock.   */
+DECL_HIDDEN_DATA(bool)                          g_fOldWinSock = false;
+/** WSAStartup   */
+DECL_HIDDEN_DATA(PFNWSASTARTUP)                 g_pfnWSAStartup = NULL;
+/** WSACleanup */
+DECL_HIDDEN_DATA(PFNWSACLEANUP)                 g_pfnWSACleanup = NULL;
+/** Pointner to WSAGetLastError (for RTErrVarsSave). */
+DECL_HIDDEN_DATA(PFNWSAGETLASTERROR)            g_pfnWSAGetLastError = NULL;
+/** Pointner to WSASetLastError (for RTErrVarsRestore). */
+DECL_HIDDEN_DATA(PFNWSASETLASTERROR)            g_pfnWSASetLastError = NULL;
+/** WSACreateEvent */
+DECL_HIDDEN_DATA(PFNWSACREATEEVENT)             g_pfnWSACreateEvent = NULL;
+/** WSACloseEvent  */
+DECL_HIDDEN_DATA(PFNWSACLOSEEVENT)              g_pfnWSACloseEvent = NULL;
+/** WSASetEvent */
+DECL_HIDDEN_DATA(PFNWSASETEVENT)                g_pfnWSASetEvent = NULL;
+/** WSAEventSelect   */
+DECL_HIDDEN_DATA(PFNWSAEVENTSELECT)             g_pfnWSAEventSelect = NULL;
+/** WSAEnumNetworkEvents */
+DECL_HIDDEN_DATA(PFNWSAENUMNETWORKEVENTS)       g_pfnWSAEnumNetworkEvents = NULL;
+/** WSASocketW */
+DECL_HIDDEN_DATA(PFNWSASOCKETW)                 g_pfnWSASocketW = NULL;
+/** WSASend */
+DECL_HIDDEN_DATA(PFNWSASEND)                    g_pfnWSASend = NULL;
+/** socket */
+DECL_HIDDEN_DATA(PFNWINSOCKSOCKET)              g_pfnsocket = NULL;
+/** closesocket */
+DECL_HIDDEN_DATA(PFNWINSOCKCLOSESOCKET)         g_pfnclosesocket = NULL;
+/** recv */
+DECL_HIDDEN_DATA(PFNWINSOCKRECV)                g_pfnrecv = NULL;
+/** send */
+DECL_HIDDEN_DATA(PFNWINSOCKSEND)                g_pfnsend = NULL;
+/** recvfrom */
+DECL_HIDDEN_DATA(PFNWINSOCKRECVFROM)            g_pfnrecvfrom = NULL;
+/** sendto */
+DECL_HIDDEN_DATA(PFNWINSOCKSENDTO)              g_pfnsendto = NULL;
+/** bind */
+DECL_HIDDEN_DATA(PFNWINSOCKBIND)                g_pfnbind = NULL;
+/** listen  */
+DECL_HIDDEN_DATA(PFNWINSOCKLISTEN)              g_pfnlisten = NULL;
+/** accept */
+DECL_HIDDEN_DATA(PFNWINSOCKACCEPT)              g_pfnaccept = NULL;
+/** connect */
+DECL_HIDDEN_DATA(PFNWINSOCKCONNECT)             g_pfnconnect = NULL;
+/** shutdown */
+DECL_HIDDEN_DATA(PFNWINSOCKSHUTDOWN)            g_pfnshutdown = NULL;
+/** getsockopt */
+DECL_HIDDEN_DATA(PFNWINSOCKGETSOCKOPT)          g_pfngetsockopt = NULL;
+/** setsockopt */
+DECL_HIDDEN_DATA(PFNWINSOCKSETSOCKOPT)          g_pfnsetsockopt = NULL;
+/** ioctlsocket */
+DECL_HIDDEN_DATA(PFNWINSOCKIOCTLSOCKET)         g_pfnioctlsocket = NULL;
+/** getpeername   */
+DECL_HIDDEN_DATA(PFNWINSOCKGETPEERNAME)         g_pfngetpeername = NULL;
+/** getsockname */
+DECL_HIDDEN_DATA(PFNWINSOCKGETSOCKNAME)         g_pfngetsockname = NULL;
+/** __WSAFDIsSet */
+DECL_HIDDEN_DATA(PFNWINSOCK__WSAFDISSET)        g_pfn__WSAFDIsSet = NULL;
+/** select */
+DECL_HIDDEN_DATA(PFNWINSOCKSELECT)              g_pfnselect = NULL;
+/** gethostbyname */
+DECL_HIDDEN_DATA(PFNWINSOCKGETHOSTBYNAME)       g_pfngethostbyname = NULL;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static LONG CALLBACK rtR3WinUnhandledXcptFilter(PEXCEPTION_POINTERS);
+
+
+/**
+ * Translates OSVERSIONINOFEX into a Windows OS type.
+ *
+ * @returns The Windows OS type.
+ * @param   pOSInfoEx       The OS info returned by Windows.
+ *
+ * @remarks This table has been assembled from Usenet postings, personal
+ *          observations, and reading other people's code.  Please feel
+ *          free to add to it or correct it.
+ * <pre>
+         dwPlatFormID  dwMajorVersion  dwMinorVersion  dwBuildNumber
+95             1              4               0             950
+95 SP1         1              4               0        >950 && <=1080
+95 OSR2        1              4             <10           >1080
+98             1              4              10            1998
+98 SP1         1              4              10       >1998 && <2183
+98 SE          1              4              10          >=2183
+ME             1              4              90            3000
+
+NT 3.51        2              3              51            1057
+NT 4           2              4               0            1381
+2000           2              5               0            2195
+XP             2              5               1            2600
+2003           2              5               2            3790
+Vista          2              6               0
+
+CE 1.0         3              1               0
+CE 2.0         3              2               0
+CE 2.1         3              2               1
+CE 3.0         3              3               0
+</pre>
+ */
+static RTWINOSTYPE rtR3InitWinSimplifiedVersion(OSVERSIONINFOEXW const *pOSInfoEx)
+{
+    RTWINOSTYPE enmVer         = kRTWinOSType_UNKNOWN;
+    BYTE  const bProductType   = pOSInfoEx->wProductType;
+    DWORD const dwPlatformId   = pOSInfoEx->dwPlatformId;
+    DWORD const dwMinorVersion = pOSInfoEx->dwMinorVersion;
+    DWORD const dwMajorVersion = pOSInfoEx->dwMajorVersion;
+    DWORD const dwBuildNumber  = pOSInfoEx->dwBuildNumber & 0xFFFF;   /* Win 9x needs this. */
+
+    if (    dwPlatformId == VER_PLATFORM_WIN32_WINDOWS
+        &&  dwMajorVersion == 4)
+    {
+        if (        dwMinorVersion < 10
+                 && dwBuildNumber == 950)
+            enmVer = kRTWinOSType_95;
+        else if (   dwMinorVersion < 10
+                 && dwBuildNumber > 950
+                 && dwBuildNumber <= 1080)
+            enmVer = kRTWinOSType_95SP1;
+        else if (   dwMinorVersion < 10
+                 && dwBuildNumber > 1080)
+            enmVer = kRTWinOSType_95OSR2;
+        else if (   dwMinorVersion == 10
+                 && dwBuildNumber == 1998)
+            enmVer = kRTWinOSType_98;
+        else if (   dwMinorVersion == 10
+                 && dwBuildNumber > 1998
+                 && dwBuildNumber < 2183)
+            enmVer = kRTWinOSType_98SP1;
+        else if (   dwMinorVersion == 10
+                 && dwBuildNumber >= 2183)
+            enmVer = kRTWinOSType_98SE;
+        else if (dwMinorVersion == 90)
+            enmVer = kRTWinOSType_ME;
+    }
+    else if (dwPlatformId == VER_PLATFORM_WIN32_NT)
+    {
+        if (dwMajorVersion == 3)
+        {
+            if (     dwMinorVersion < 50)
+                enmVer = kRTWinOSType_NT310;
+            else if (dwMinorVersion == 50)
+                enmVer = kRTWinOSType_NT350;
+            else
+                enmVer = kRTWinOSType_NT351;
+        }
+        else if (dwMajorVersion == 4)
+            enmVer = kRTWinOSType_NT4;
+        else if (dwMajorVersion == 5)
+        {
+            if (dwMinorVersion == 0)
+                enmVer = kRTWinOSType_2K;
+            else if (dwMinorVersion == 1)
+                enmVer = kRTWinOSType_XP;
+            else
+                enmVer = kRTWinOSType_2003;
+        }
+        else if (dwMajorVersion == 6)
+        {
+            if (dwMinorVersion == 0)
+                enmVer = bProductType != VER_NT_WORKSTATION ? kRTWinOSType_2008   : kRTWinOSType_VISTA;
+            else if (dwMinorVersion == 1)
+                enmVer = bProductType != VER_NT_WORKSTATION ? kRTWinOSType_2008R2 : kRTWinOSType_7;
+            else if (dwMinorVersion == 2)
+                enmVer = bProductType != VER_NT_WORKSTATION ? kRTWinOSType_2012   : kRTWinOSType_8;
+            else if (dwMinorVersion == 3)
+                enmVer = bProductType != VER_NT_WORKSTATION ? kRTWinOSType_2012R2 : kRTWinOSType_81;
+            else if (dwMinorVersion == 4)
+                enmVer = bProductType != VER_NT_WORKSTATION ? kRTWinOSType_2016   : kRTWinOSType_10;
+            else
+                enmVer = kRTWinOSType_NT_UNKNOWN;
+        }
+        else if (dwMajorVersion == 10)
+        {
+            if (dwMinorVersion == 0)
+            {
+                /* The version detection for server 2019, server 2022 and windows 11
+                   are by build number.  Stupid, stupid, Microsoft. */
+                if (bProductType == VER_NT_WORKSTATION)
+                    enmVer = dwBuildNumber >= 22000 ? kRTWinOSType_11 : kRTWinOSType_10;
+                else
+                    enmVer = dwBuildNumber >= 20348 ? kRTWinOSType_2022
+                           : dwBuildNumber >= 17763 ? kRTWinOSType_2019 : kRTWinOSType_2016;
+            }
+            else
+                enmVer = kRTWinOSType_NT_UNKNOWN;
+        }
+        else
+            enmVer = kRTWinOSType_NT_UNKNOWN;
+    }
+
+    return enmVer;
+}
+
+
+/**
+ * Initializes the global variables related to windows version.
+ */
+static void rtR3InitWindowsVersion(void)
+{
+    Assert(g_hModNtDll != NULL);
+
+    /*
+     * ASSUMES OSVERSIONINFOEX starts with the exact same layout as OSVERSIONINFO (safe).
+     */
+    AssertCompileMembersSameSizeAndOffset(OSVERSIONINFOEX, szCSDVersion, OSVERSIONINFO, szCSDVersion);
+    AssertCompileMemberOffset(OSVERSIONINFOEX, wServicePackMajor, sizeof(OSVERSIONINFO));
+
+    /*
+     * Use the NT version of RtlGetVersion (since w2k) so we don't get fooled
+     * by the standard compatibility shims.  (Sandboxes may still fool us.)
+     *
+     * Note! This API was added in windows 2000 together with the extended
+     *       version info structure (OSVERSIONINFOEXW), so there is no need
+     *       to retry with the smaller version (OSVERSIONINFOW).
+     */
+    RT_ZERO(g_WinOsInfoEx);
+    g_WinOsInfoEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEXW);
+
+    LONG (__stdcall *pfnRtlGetVersion)(OSVERSIONINFOEXW *);
+    *(FARPROC *)&pfnRtlGetVersion = GetProcAddress(g_hModNtDll, "RtlGetVersion");
+    LONG rcNt = -1;
+    if (pfnRtlGetVersion)
+        rcNt = pfnRtlGetVersion(&g_WinOsInfoEx);
+    if (rcNt != 0)
+    {
+        /*
+         * Couldn't find it or it failed, try the windows version of the API.
+         * The GetVersionExW API was added in NT 3.51, however only the small
+         * structure version existed till windows 2000.  We'll try the larger
+         * structure version first, anyway, just in case.
+         */
+        RT_ZERO(g_WinOsInfoEx);
+        g_WinOsInfoEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEXW);
+
+        BOOL (__stdcall *pfnGetVersionExW)(OSVERSIONINFOW *);
+        *(FARPROC *)&pfnGetVersionExW = GetProcAddress(g_hModKernel32, "GetVersionExW");
+
+        if (!pfnGetVersionExW || !pfnGetVersionExW((POSVERSIONINFOW)&g_WinOsInfoEx))
+        {
+            /*
+             * If that didn't work either, just get the basic version bits.
+             */
+            RT_ZERO(g_WinOsInfoEx);
+            g_WinOsInfoEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFOW);
+            if (pfnGetVersionExW && pfnGetVersionExW((POSVERSIONINFOW)&g_WinOsInfoEx))
+                Assert(g_WinOsInfoEx.dwPlatformId != VER_PLATFORM_WIN32_NT || g_WinOsInfoEx.dwMajorVersion < 5);
+            else
+            {
+                /*
+                 * Okay, nothing worked, so use GetVersion.
+                 *
+                 * This should only happen if we're on NT 3.1 or NT 3.50.
+                 * It should never happen for 64-bit builds.
+                 */
+#ifdef RT_ARCH_X86
+                RT_ZERO(g_WinOsInfoEx);
+                DWORD const dwVersion = GetVersion();
+
+                /* Common fields: */
+                g_WinOsInfoEx.dwMajorVersion        = dwVersion & 0xff;
+                g_WinOsInfoEx.dwMinorVersion        = (dwVersion >> 8) & 0xff;
+                if (!(dwVersion & RT_BIT_32(31)))
+                    g_WinOsInfoEx.dwBuildNumber     = dwVersion >> 16;
+                else
+                    g_WinOsInfoEx.dwBuildNumber     = 511;
+                g_WinOsInfoEx.dwPlatformId          = VER_PLATFORM_WIN32_NT;
+                /** @todo get CSD from registry. */
+#else
+                AssertBreakpoint();
+                RT_ZERO(g_WinOsInfoEx);
+#endif
+            }
+
+#ifdef RT_ARCH_X86
+            /*
+             * Fill in some of the extended info too.
+             */
+            g_WinOsInfoEx.dwOSVersionInfoSize       = sizeof(OSVERSIONINFOEXW); /* Pretend. */
+            g_WinOsInfoEx.wProductType              = VER_NT_WORKSTATION;
+            NT_PRODUCT_TYPE enmProdType = NtProductWinNt;
+            if (RtlGetNtProductType(&enmProdType))
+                g_WinOsInfoEx.wProductType = (BYTE)enmProdType;
+            /** @todo parse the CSD string to figure that version. */
+#endif
+        }
+    }
+
+    if (g_WinOsInfoEx.dwOSVersionInfoSize)
+        g_enmWinVer = rtR3InitWinSimplifiedVersion(&g_WinOsInfoEx);
+}
+
+
+/**
+ * Resolves the winsock error APIs.
+ */
+static void rtR3InitWinSockApis(void)
+{
+    /*
+     * Try get ws2_32.dll, then try load it, then finally fall back to the old
+     * wsock32.dll.  We use RTLdrLoadSystem to the loading as it has all the fancy
+     * logic for safely doing that.
+     */
+    g_hModWinSock = GetModuleHandleW(L"ws2_32.dll");
+    if (g_hModWinSock == NULL)
+    {
+        RTLDRMOD hLdrMod;
+        int rc = RTLdrLoadSystem("ws2_32.dll", true /*fNoUnload*/, &hLdrMod);
+        if (RT_FAILURE(rc))
+        {
+            rc = RTLdrLoadSystem("wsock32.dll", true /*fNoUnload*/, &hLdrMod);
+            if (RT_FAILURE(rc))
+            {
+                AssertMsgFailed(("rc=%Rrc\n", rc));
+                return;
+            }
+            g_fOldWinSock = true;
+        }
+        g_hModWinSock = (HMODULE)RTLdrGetNativeHandle(hLdrMod);
+        RTLdrClose(hLdrMod);
+    }
+
+    g_pfnWSAStartup           = (decltype(g_pfnWSAStartup))         GetProcAddress(g_hModWinSock, "WSAStartup");
+    g_pfnWSACleanup           = (decltype(g_pfnWSACleanup))         GetProcAddress(g_hModWinSock, "WSACleanup");
+    g_pfnWSAGetLastError      = (decltype(g_pfnWSAGetLastError))    GetProcAddress(g_hModWinSock, "WSAGetLastError");
+    g_pfnWSASetLastError      = (decltype(g_pfnWSASetLastError))    GetProcAddress(g_hModWinSock, "WSASetLastError");
+    g_pfnWSACreateEvent       = (decltype(g_pfnWSACreateEvent))     GetProcAddress(g_hModWinSock, "WSACreateEvent");
+    g_pfnWSACloseEvent        = (decltype(g_pfnWSACloseEvent))      GetProcAddress(g_hModWinSock, "WSACloseEvent");
+    g_pfnWSASetEvent          = (decltype(g_pfnWSASetEvent))        GetProcAddress(g_hModWinSock, "WSASetEvent");
+    g_pfnWSAEventSelect       = (decltype(g_pfnWSAEventSelect))     GetProcAddress(g_hModWinSock, "WSAEventSelect");
+    g_pfnWSAEnumNetworkEvents = (decltype(g_pfnWSAEnumNetworkEvents))GetProcAddress(g_hModWinSock,"WSAEnumNetworkEvents");
+    g_pfnWSASocketW           = (decltype(g_pfnWSASocketW))         GetProcAddress(g_hModWinSock, "WSASocketW");
+    g_pfnWSASend              = (decltype(g_pfnWSASend))            GetProcAddress(g_hModWinSock, "WSASend");
+    g_pfnsocket               = (decltype(g_pfnsocket))             GetProcAddress(g_hModWinSock, "socket");
+    g_pfnclosesocket          = (decltype(g_pfnclosesocket))        GetProcAddress(g_hModWinSock, "closesocket");
+    g_pfnrecv                 = (decltype(g_pfnrecv))               GetProcAddress(g_hModWinSock, "recv");
+    g_pfnsend                 = (decltype(g_pfnsend))               GetProcAddress(g_hModWinSock, "send");
+    g_pfnrecvfrom             = (decltype(g_pfnrecvfrom))           GetProcAddress(g_hModWinSock, "recvfrom");
+    g_pfnsendto               = (decltype(g_pfnsendto))             GetProcAddress(g_hModWinSock, "sendto");
+    g_pfnbind                 = (decltype(g_pfnbind))               GetProcAddress(g_hModWinSock, "bind");
+    g_pfnlisten               = (decltype(g_pfnlisten))             GetProcAddress(g_hModWinSock, "listen");
+    g_pfnaccept               = (decltype(g_pfnaccept))             GetProcAddress(g_hModWinSock, "accept");
+    g_pfnconnect              = (decltype(g_pfnconnect))            GetProcAddress(g_hModWinSock, "connect");
+    g_pfnshutdown             = (decltype(g_pfnshutdown))           GetProcAddress(g_hModWinSock, "shutdown");
+    g_pfngetsockopt           = (decltype(g_pfngetsockopt))         GetProcAddress(g_hModWinSock, "getsockopt");
+    g_pfnsetsockopt           = (decltype(g_pfnsetsockopt))         GetProcAddress(g_hModWinSock, "setsockopt");
+    g_pfnioctlsocket          = (decltype(g_pfnioctlsocket))        GetProcAddress(g_hModWinSock, "ioctlsocket");
+    g_pfngetpeername          = (decltype(g_pfngetpeername))        GetProcAddress(g_hModWinSock, "getpeername");
+    g_pfngetsockname          = (decltype(g_pfngetsockname))        GetProcAddress(g_hModWinSock, "getsockname");
+    g_pfn__WSAFDIsSet         = (decltype(g_pfn__WSAFDIsSet))       GetProcAddress(g_hModWinSock, "__WSAFDIsSet");
+    g_pfnselect               = (decltype(g_pfnselect))             GetProcAddress(g_hModWinSock, "select");
+    g_pfngethostbyname        = (decltype(g_pfngethostbyname))      GetProcAddress(g_hModWinSock, "gethostbyname");
+
+    Assert(g_pfnWSAStartup);
+    Assert(g_pfnWSACleanup);
+    Assert(g_pfnWSAGetLastError);
+    Assert(g_pfnWSASetLastError);
+    Assert(g_pfnWSACreateEvent       || g_fOldWinSock);
+    Assert(g_pfnWSACloseEvent        || g_fOldWinSock);
+    Assert(g_pfnWSASetEvent          || g_fOldWinSock);
+    Assert(g_pfnWSAEventSelect       || g_fOldWinSock);
+    Assert(g_pfnWSAEnumNetworkEvents || g_fOldWinSock);
+    Assert(g_pfnWSASocketW           || g_fOldWinSock);
+    Assert(g_pfnWSASend              || g_fOldWinSock);
+    Assert(g_pfnsocket);
+    Assert(g_pfnclosesocket);
+    Assert(g_pfnrecv);
+    Assert(g_pfnsend);
+    Assert(g_pfnrecvfrom);
+    Assert(g_pfnsendto);
+    Assert(g_pfnbind);
+    Assert(g_pfnlisten);
+    Assert(g_pfnaccept);
+    Assert(g_pfnconnect);
+    Assert(g_pfnshutdown);
+    Assert(g_pfngetsockopt);
+    Assert(g_pfnsetsockopt);
+    Assert(g_pfnioctlsocket);
+    Assert(g_pfngetpeername);
+    Assert(g_pfngetsockname);
+    Assert(g_pfn__WSAFDIsSet);
+    Assert(g_pfnselect);
+    Assert(g_pfngethostbyname);
+}
+
+
+static int rtR3InitNativeObtrusiveWorker(uint32_t fFlags)
+{
+    /*
+     * Disable error popups.
+     */
+    UINT fOldErrMode = SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
+    SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX | fOldErrMode);
+
+    /*
+     * Restrict DLL searching for the process on windows versions which allow
+     * us to do so.
+     *  - The first trick works on XP SP1+ and disables the searching of the
+     *    current directory.
+     *  - The second trick is W7 w/ KB2533623 and W8+, it restrict the DLL
+     *    searching to the application directory (except when
+     *    RTR3INIT_FLAGS_STANDALONE_APP is given) and the System32 directory.
+     */
+    int rc = VINF_SUCCESS;
+
+    typedef BOOL (WINAPI *PFNSETDLLDIRECTORY)(LPCWSTR);
+    PFNSETDLLDIRECTORY pfnSetDllDir = (PFNSETDLLDIRECTORY)GetProcAddress(g_hModKernel32, "SetDllDirectoryW");
+    if (pfnSetDllDir)
+    {
+        if (pfnSetDllDir(L""))
+            g_enmWinLdrProt = RTR3WINLDRPROT_NO_CWD;
+        else
+            rc = VERR_INTERNAL_ERROR_3;
+    }
+
+    /** @bugref{6861} Observed GUI issues on Vista (32-bit and 64-bit) when using
+     *                SetDefaultDllDirectories.
+     *  @bugref{8194} Try use SetDefaultDllDirectories on Vista for standalone apps
+     *                despite potential GUI issues. */
+    if (   g_enmWinVer > kRTWinOSType_VISTA
+        || (fFlags & RTR3INIT_FLAGS_STANDALONE_APP))
+    {
+        typedef BOOL(WINAPI *PFNSETDEFAULTDLLDIRECTORIES)(DWORD);
+        PFNSETDEFAULTDLLDIRECTORIES pfnSetDefDllDirs;
+        pfnSetDefDllDirs = (PFNSETDEFAULTDLLDIRECTORIES)GetProcAddress(g_hModKernel32, "SetDefaultDllDirectories");
+        if (pfnSetDefDllDirs)
+        {
+            DWORD fDllDirs = LOAD_LIBRARY_SEARCH_SYSTEM32;
+            if (!(fFlags & RTR3INIT_FLAGS_STANDALONE_APP))
+                fDllDirs |= LOAD_LIBRARY_SEARCH_APPLICATION_DIR;
+            if (pfnSetDefDllDirs(fDllDirs))
+                g_enmWinLdrProt = fDllDirs & LOAD_LIBRARY_SEARCH_APPLICATION_DIR ? RTR3WINLDRPROT_SAFE : RTR3WINLDRPROT_SAFER;
+            else if (RT_SUCCESS(rc))
+                rc = VERR_INTERNAL_ERROR_4;
+        }
+    }
+
+    /*
+     * Register an unhandled exception callback if we can.
+     */
+    g_pfnGetCurrentThreadStackLimits = (PFNGETCURRENTTHREADSTACKLIMITS)GetProcAddress(g_hModKernel32, "GetCurrentThreadStackLimits");
+    g_pfnSetUnhandledExceptionFilter = (decltype(SetUnhandledExceptionFilter) *)GetProcAddress(g_hModKernel32, "SetUnhandledExceptionFilter");
+    g_pfnUnhandledExceptionFilter    = (decltype(UnhandledExceptionFilter) *)   GetProcAddress(g_hModKernel32, "UnhandledExceptionFilter");
+    if (g_pfnSetUnhandledExceptionFilter && !g_pfnUnhandledXcptFilter)
+    {
+        g_pfnUnhandledXcptFilter = g_pfnSetUnhandledExceptionFilter(rtR3WinUnhandledXcptFilter);
+        AssertStmt(g_pfnUnhandledXcptFilter != rtR3WinUnhandledXcptFilter, g_pfnUnhandledXcptFilter = NULL);
+    }
+
+    return rc;
+}
+
+
+DECLHIDDEN(int) rtR3InitNativeFirst(uint32_t fFlags)
+{
+    /*
+     * Make sure we've got the handles of the two main Windows NT dlls.
+     */
+    g_hModKernel32 = GetModuleHandleW(L"kernel32.dll");
+    if (g_hModKernel32 == NULL)
+        return VERR_INTERNAL_ERROR_2;
+    g_hModNtDll    = GetModuleHandleW(L"ntdll.dll");
+    if (g_hModNtDll == NULL)
+        return VERR_INTERNAL_ERROR_2;
+
+    rtR3InitWindowsVersion();
+
+    int rc = VINF_SUCCESS;
+    if (!(fFlags & RTR3INIT_FLAGS_UNOBTRUSIVE))
+        rc = rtR3InitNativeObtrusiveWorker(fFlags);
+
+    /*
+     * Resolve some kernel32.dll APIs we may need but aren't necessarily
+     * present in older windows versions.
+     */
+    g_pfnGetSystemWindowsDirectoryW      = (PFNGETWINSYSDIR)GetProcAddress(g_hModKernel32, "GetSystemWindowsDirectoryW");
+    if (g_pfnGetSystemWindowsDirectoryW)
+        g_pfnGetSystemWindowsDirectoryW  = (PFNGETWINSYSDIR)GetProcAddress(g_hModKernel32, "GetWindowsDirectoryW");
+    g_pfnSystemTimeToTzSpecificLocalTime = (decltype(SystemTimeToTzSpecificLocalTime) *)GetProcAddress(g_hModKernel32, "SystemTimeToTzSpecificLocalTime");
+    g_pfnCreateWaitableTimerExW     = (PFNCREATEWAITABLETIMEREX)              GetProcAddress(g_hModKernel32, "CreateWaitableTimerExW");
+    g_pfnGetHandleInformation       = (decltype(GetHandleInformation) *)      GetProcAddress(g_hModKernel32, "GetHandleInformation");
+    g_pfnSetHandleInformation       = (decltype(SetHandleInformation) *)      GetProcAddress(g_hModKernel32, "SetHandleInformation");
+    g_pfnIsDebuggerPresent          = (decltype(IsDebuggerPresent) *)         GetProcAddress(g_hModKernel32, "IsDebuggerPresent");
+    g_pfnGetSystemTimeAsFileTime    = (decltype(GetSystemTimeAsFileTime) *)   GetProcAddress(g_hModKernel32, "GetSystemTimeAsFileTime");
+    g_pfnGetProcessAffinityMask     = (decltype(GetProcessAffinityMask) *)    GetProcAddress(g_hModKernel32, "GetProcessAffinityMask");
+    g_pfnSetThreadAffinityMask      = (decltype(SetThreadAffinityMask) *)     GetProcAddress(g_hModKernel32, "SetThreadAffinityMask");
+    g_pfnCreateIoCompletionPort     = (decltype(CreateIoCompletionPort) *)    GetProcAddress(g_hModKernel32, "CreateIoCompletionPort");
+    g_pfnGetQueuedCompletionStatus  = (decltype(GetQueuedCompletionStatus) *) GetProcAddress(g_hModKernel32, "GetQueuedCompletionStatus");
+    g_pfnPostQueuedCompletionStatus = (decltype(PostQueuedCompletionStatus) *)GetProcAddress(g_hModKernel32, "PostQueuedCompletionStatus");
+    g_pfnIsProcessorFeaturePresent  = (decltype(IsProcessorFeaturePresent) *) GetProcAddress(g_hModKernel32, "IsProcessorFeaturePresent");
+
+    Assert(g_pfnGetHandleInformation       || g_enmWinVer < kRTWinOSType_NT351);
+    Assert(g_pfnSetHandleInformation       || g_enmWinVer < kRTWinOSType_NT351);
+    Assert(g_pfnIsDebuggerPresent          || g_enmWinVer < kRTWinOSType_NT4);
+    Assert(g_pfnGetSystemTimeAsFileTime    || g_enmWinVer < kRTWinOSType_NT4);
+    Assert(g_pfnGetProcessAffinityMask     || g_enmWinVer < kRTWinOSType_NT350);
+    Assert(g_pfnSetThreadAffinityMask      || g_enmWinVer < kRTWinOSType_NT350);
+    Assert(g_pfnCreateIoCompletionPort     || g_enmWinVer < kRTWinOSType_NT350);
+    Assert(g_pfnGetQueuedCompletionStatus  || g_enmWinVer < kRTWinOSType_NT350);
+    Assert(g_pfnPostQueuedCompletionStatus || g_enmWinVer < kRTWinOSType_NT350);
+    Assert(g_pfnIsProcessorFeaturePresent  || g_enmWinVer < kRTWinOSType_NT4);
+
+    /*
+     * Resolve some ntdll.dll APIs that weren't there in early NT versions.
+     */
+    g_pfnNtQueryFullAttributesFile  = (PFNNTQUERYFULLATTRIBUTESFILE)GetProcAddress(g_hModNtDll, "NtQueryFullAttributesFile");
+    g_pfnNtDuplicateToken           = (PFNNTDUPLICATETOKEN)GetProcAddress(         g_hModNtDll, "NtDuplicateToken");
+    g_pfnNtAlertThread              = (decltype(NtAlertThread) *)GetProcAddress(   g_hModNtDll, "NtAlertThread");
+
+    /*
+     * Resolve the winsock error getter and setter so assertions can save those too.
+     */
+    rtR3InitWinSockApis();
+
+    return rc;
+}
+
+
+DECLHIDDEN(void) rtR3InitNativeObtrusive(uint32_t fFlags)
+{
+    rtR3InitNativeObtrusiveWorker(fFlags);
+}
+
+
+DECLHIDDEN(int) rtR3InitNativeFinal(uint32_t fFlags)
+{
+    /* Nothing to do here. */
+    RT_NOREF_PV(fFlags);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Unhandled exception filter callback.
+ *
+ * Will try log stuff.
+ */
+static LONG CALLBACK rtR3WinUnhandledXcptFilter(PEXCEPTION_POINTERS pPtrs)
+{
+    /*
+     * Try get the logger and log exception details.
+     *
+     * Note! We'll be using RTLogLoggerWeak for now, though we should probably add
+     *       a less deadlock prone API here and gives up pretty fast if it
+     *       cannot get the lock...
+     */
+    PRTLOGGER pLogger = RTLogRelGetDefaultInstanceWeak();
+    if (!pLogger)
+        pLogger = RTLogGetDefaultInstanceWeak();
+    if (pLogger)
+    {
+        RTLogLoggerWeak(pLogger, NULL, "\n!!! rtR3WinUnhandledXcptFilter caught an exception on thread %p in %u !!!\n",
+                        RTThreadNativeSelf(), RTProcSelf());
+
+        /*
+         * Dump the exception record.
+         */
+        uintptr_t         uXcptPC  = 0;
+        PEXCEPTION_RECORD pXcptRec = RT_VALID_PTR(pPtrs) && RT_VALID_PTR(pPtrs->ExceptionRecord) ? pPtrs->ExceptionRecord : NULL;
+        if (pXcptRec)
+        {
+            RTLogLoggerWeak(pLogger, NULL, "\nExceptionCode=%#010x ExceptionFlags=%#010x ExceptionAddress=%p\n",
+                            pXcptRec->ExceptionCode, pXcptRec->ExceptionFlags, pXcptRec->ExceptionAddress);
+            for (uint32_t i = 0; i < RT_MIN(pXcptRec->NumberParameters, EXCEPTION_MAXIMUM_PARAMETERS); i++)
+                RTLogLoggerWeak(pLogger, NULL, "ExceptionInformation[%d]=%p\n", i, pXcptRec->ExceptionInformation[i]);
+            uXcptPC = (uintptr_t)pXcptRec->ExceptionAddress;
+
+            /* Nested? Display one level only. */
+            PEXCEPTION_RECORD pNestedRec = pXcptRec->ExceptionRecord;
+            if (RT_VALID_PTR(pNestedRec))
+            {
+                RTLogLoggerWeak(pLogger, NULL, "Nested: ExceptionCode=%#010x ExceptionFlags=%#010x ExceptionAddress=%p (nested %p)\n",
+                                pNestedRec->ExceptionCode, pNestedRec->ExceptionFlags, pNestedRec->ExceptionAddress,
+                                pNestedRec->ExceptionRecord);
+                for (uint32_t i = 0; i < RT_MIN(pNestedRec->NumberParameters, EXCEPTION_MAXIMUM_PARAMETERS); i++)
+                    RTLogLoggerWeak(pLogger, NULL, "Nested: ExceptionInformation[%d]=%p\n", i, pNestedRec->ExceptionInformation[i]);
+                uXcptPC = (uintptr_t)pNestedRec->ExceptionAddress;
+            }
+        }
+
+        /*
+         * Dump the context record.
+         */
+        volatile char   szMarker[] = "stackmarker";
+        uintptr_t       uXcptSP = (uintptr_t)&szMarker[0];
+        PCONTEXT pXcptCtx = RT_VALID_PTR(pPtrs) && RT_VALID_PTR(pPtrs->ContextRecord)   ? pPtrs->ContextRecord   : NULL;
+        if (pXcptCtx)
+        {
+#ifdef RT_ARCH_AMD64
+            RTLogLoggerWeak(pLogger, NULL, "\ncs:rip=%04x:%016RX64\n", pXcptCtx->SegCs, pXcptCtx->Rip);
+            RTLogLoggerWeak(pLogger, NULL, "ss:rsp=%04x:%016RX64 rbp=%016RX64\n", pXcptCtx->SegSs, pXcptCtx->Rsp, pXcptCtx->Rbp);
+            RTLogLoggerWeak(pLogger, NULL, "rax=%016RX64 rcx=%016RX64 rdx=%016RX64 rbx=%016RX64\n",
+                            pXcptCtx->Rax, pXcptCtx->Rcx, pXcptCtx->Rdx, pXcptCtx->Rbx);
+            RTLogLoggerWeak(pLogger, NULL, "rsi=%016RX64 rdi=%016RX64 rsp=%016RX64 rbp=%016RX64\n",
+                            pXcptCtx->Rsi, pXcptCtx->Rdi, pXcptCtx->Rsp, pXcptCtx->Rbp);
+            RTLogLoggerWeak(pLogger, NULL, "r8 =%016RX64 r9 =%016RX64 r10=%016RX64 r11=%016RX64\n",
+                            pXcptCtx->R8,  pXcptCtx->R9,  pXcptCtx->R10, pXcptCtx->R11);
+            RTLogLoggerWeak(pLogger, NULL, "r12=%016RX64 r13=%016RX64 r14=%016RX64 r15=%016RX64\n",
+                            pXcptCtx->R12,  pXcptCtx->R13,  pXcptCtx->R14, pXcptCtx->R15);
+            RTLogLoggerWeak(pLogger, NULL, "ds=%04x es=%04x fs=%04x gs=%04x eflags=%08x\n",
+                            pXcptCtx->SegDs, pXcptCtx->SegEs, pXcptCtx->SegFs, pXcptCtx->SegGs, pXcptCtx->EFlags);
+            RTLogLoggerWeak(pLogger, NULL, "p1home=%016RX64 p2home=%016RX64 pe3home=%016RX64\n",
+                            pXcptCtx->P1Home, pXcptCtx->P2Home, pXcptCtx->P3Home);
+            RTLogLoggerWeak(pLogger, NULL, "p4home=%016RX64 p5home=%016RX64 pe6home=%016RX64\n",
+                            pXcptCtx->P4Home, pXcptCtx->P5Home, pXcptCtx->P6Home);
+            RTLogLoggerWeak(pLogger, NULL, "   LastBranchToRip=%016RX64    LastBranchFromRip=%016RX64\n",
+                            pXcptCtx->LastBranchToRip, pXcptCtx->LastBranchFromRip);
+            RTLogLoggerWeak(pLogger, NULL, "LastExceptionToRip=%016RX64 LastExceptionFromRip=%016RX64\n",
+                            pXcptCtx->LastExceptionToRip, pXcptCtx->LastExceptionFromRip);
+            uXcptSP = pXcptCtx->Rsp;
+            uXcptPC = pXcptCtx->Rip;
+
+#elif defined(RT_ARCH_X86)
+            RTLogLoggerWeak(pLogger, NULL, "\ncs:eip=%04x:%08RX32\n", pXcptCtx->SegCs, pXcptCtx->Eip);
+            RTLogLoggerWeak(pLogger, NULL, "ss:esp=%04x:%08RX32 ebp=%08RX32\n", pXcptCtx->SegSs, pXcptCtx->Esp, pXcptCtx->Ebp);
+            RTLogLoggerWeak(pLogger, NULL, "eax=%08RX32 ecx=%08RX32 edx=%08RX32 ebx=%08RX32\n",
+                            pXcptCtx->Eax, pXcptCtx->Ecx,  pXcptCtx->Edx,  pXcptCtx->Ebx);
+            RTLogLoggerWeak(pLogger, NULL, "esi=%08RX32 edi=%08RX32 esp=%08RX32 ebp=%08RX32\n",
+                            pXcptCtx->Esi, pXcptCtx->Edi,  pXcptCtx->Esp,  pXcptCtx->Ebp);
+            RTLogLoggerWeak(pLogger, NULL, "ds=%04x es=%04x fs=%04x gs=%04x eflags=%08x\n",
+                            pXcptCtx->SegDs, pXcptCtx->SegEs, pXcptCtx->SegFs, pXcptCtx->SegGs, pXcptCtx->EFlags);
+            uXcptSP = pXcptCtx->Esp;
+            uXcptPC = pXcptCtx->Eip;
+#endif
+        }
+
+        /*
+         * Dump stack.
+         */
+        uintptr_t uStack = (uintptr_t)(void *)&szMarker[0];
+        uStack -= uStack & 15;
+
+        size_t cbToDump = PAGE_SIZE - (uStack & PAGE_OFFSET_MASK);
+        if (cbToDump < 512)
+            cbToDump += PAGE_SIZE;
+        size_t cbToXcpt = uXcptSP - uStack;
+        while (cbToXcpt > cbToDump && cbToXcpt <= _16K)
+            cbToDump += PAGE_SIZE;
+        ULONG_PTR uLow  = (uintptr_t)&szMarker[0];
+        ULONG_PTR uHigh = (uintptr_t)&szMarker[0];
+        if (g_pfnGetCurrentThreadStackLimits)
+        {
+            g_pfnGetCurrentThreadStackLimits(&uLow, &uHigh);
+            size_t cbToTop = RT_MAX(uLow, uHigh) - uStack;
+            if (cbToTop < _1M)
+                cbToDump = cbToTop;
+        }
+
+        RTLogLoggerWeak(pLogger, NULL, "\nStack %p, dumping %#x bytes (low=%p, high=%p)\n", uStack, cbToDump, uLow, uHigh);
+        RTLogLoggerWeak(pLogger, NULL, "%.*RhxD\n", cbToDump, uStack);
+
+        /*
+         * Try figure the thread name.
+         *
+         * Note! This involves the thread db lock, so it may deadlock, which
+         *       is why it's at the end.
+         */
+        RTLogLoggerWeak(pLogger, NULL,  "Thread ID:   %p\n", RTThreadNativeSelf());
+        RTLogLoggerWeak(pLogger, NULL,  "Thread name: %s\n", RTThreadSelfName());
+        RTLogLoggerWeak(pLogger, NULL,  "Thread IPRT: %p\n", RTThreadSelf());
+
+        /*
+         * Try dump the load information.
+         */
+        PPEB pPeb = RTNtCurrentPeb();
+        if (RT_VALID_PTR(pPeb))
+        {
+            PPEB_LDR_DATA pLdrData = pPeb->Ldr;
+            if (RT_VALID_PTR(pLdrData))
+            {
+                PLDR_DATA_TABLE_ENTRY pFound     = NULL;
+                LIST_ENTRY * const    pList      = &pLdrData->InMemoryOrderModuleList;
+                LIST_ENTRY           *pListEntry = pList->Flink;
+                uint32_t              cLoops     = 0;
+                RTLogLoggerWeak(pLogger, NULL,
+                                "\nLoaded Modules:\n"
+                                "%-*s[*] Timestamp Path\n", sizeof(void *) * 4 + 2 - 1, "Address range"
+                                );
+                while (pListEntry != pList && RT_VALID_PTR(pListEntry) && cLoops < 1024)
+                {
+                    PLDR_DATA_TABLE_ENTRY pLdrEntry = RT_FROM_MEMBER(pListEntry, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);
+                    uint32_t const        cbLength  = (uint32_t)(uintptr_t)pLdrEntry->Reserved3[1];
+                    char                  chInd     = ' ';
+                    if (uXcptPC - (uintptr_t)pLdrEntry->DllBase < cbLength)
+                    {
+                        chInd = '*';
+                        pFound = pLdrEntry;
+                    }
+
+                    if (   RT_VALID_PTR(pLdrEntry->FullDllName.Buffer)
+                        && pLdrEntry->FullDllName.Length > 0
+                        && pLdrEntry->FullDllName.Length < _8K
+                        && (pLdrEntry->FullDllName.Length & 1) == 0
+                        && pLdrEntry->FullDllName.Length <= pLdrEntry->FullDllName.MaximumLength)
+                        RTLogLoggerWeak(pLogger, NULL, "%p..%p%c  %08RX32  %.*ls\n",
+                                        pLdrEntry->DllBase, (uintptr_t)pLdrEntry->DllBase + cbLength - 1, chInd,
+                                        pLdrEntry->TimeDateStamp, pLdrEntry->FullDllName.Length / sizeof(RTUTF16),
+                                        pLdrEntry->FullDllName.Buffer);
+                    else
+                        RTLogLoggerWeak(pLogger, NULL, "%p..%p%c  %08RX32  <bad or missing: %p LB %#x max %#x\n",
+                                        pLdrEntry->DllBase, (uintptr_t)pLdrEntry->DllBase + cbLength - 1, chInd,
+                                        pLdrEntry->TimeDateStamp, pLdrEntry->FullDllName.Buffer, pLdrEntry->FullDllName.Length,
+                                        pLdrEntry->FullDllName.MaximumLength);
+
+                    /* advance */
+                    pListEntry = pListEntry->Flink;
+                    cLoops++;
+                }
+
+                /*
+                 * Use the above to pick out code addresses on the stack.
+                 */
+                if (   cLoops < 1024
+                    && uXcptSP - uStack < cbToDump)
+                {
+                    RTLogLoggerWeak(pLogger, NULL, "\nPotential code addresses on the stack:\n");
+                    if (pFound)
+                    {
+                        if (   RT_VALID_PTR(pFound->FullDllName.Buffer)
+                            && pFound->FullDllName.Length > 0
+                            && pFound->FullDllName.Length < _8K
+                            && (pFound->FullDllName.Length & 1) == 0
+                            && pFound->FullDllName.Length <= pFound->FullDllName.MaximumLength)
+                            RTLogLoggerWeak(pLogger, NULL, "%-*s: %p - %#010RX32 bytes into %.*ls\n",
+                                            sizeof(void *) * 2, "Xcpt PC", uXcptPC, (uint32_t)(uXcptPC - (uintptr_t)pFound->DllBase),
+                                            pFound->FullDllName.Length / sizeof(RTUTF16), pFound->FullDllName.Buffer);
+                        else
+                            RTLogLoggerWeak(pLogger, NULL, "%-*s: %p - %08RX32 into module at %p\n",
+                                            sizeof(void *) * 2, "Xcpt PC", uXcptPC, (uint32_t)(uXcptPC - (uintptr_t)pFound->DllBase),
+                                            pFound->DllBase);
+                    }
+
+                    uintptr_t const *puStack = (uintptr_t const *)uXcptSP;
+                    uintptr_t        cLeft   = (cbToDump - (uXcptSP - uStack)) / sizeof(uintptr_t);
+                    while (cLeft-- > 0)
+                    {
+                        uintptr_t uPtr = *puStack;
+                        if (RT_VALID_PTR(uPtr))
+                        {
+                            /* Search the module table. */
+                            pFound     = NULL;
+                            cLoops     = 0;
+                            pListEntry = pList->Flink;
+                            while (pListEntry != pList && RT_VALID_PTR(pListEntry) && cLoops < 1024)
+                            {
+                                PLDR_DATA_TABLE_ENTRY pLdrEntry = RT_FROM_MEMBER(pListEntry, LDR_DATA_TABLE_ENTRY, InMemoryOrderLinks);
+                                uint32_t const        cbLength  = (uint32_t)(uintptr_t)pLdrEntry->Reserved3[1];
+                                if (uPtr - (uintptr_t)pLdrEntry->DllBase < cbLength)
+                                {
+                                    pFound = pLdrEntry;
+                                    break;
+                                }
+
+                                /* advance */
+                                pListEntry = pListEntry->Flink;
+                                cLoops++;
+                            }
+
+                            if (pFound)
+                            {
+                                if (   RT_VALID_PTR(pFound->FullDllName.Buffer)
+                                    && pFound->FullDllName.Length > 0
+                                    && pFound->FullDllName.Length < _8K
+                                    && (pFound->FullDllName.Length & 1) == 0
+                                    && pFound->FullDllName.Length <= pFound->FullDllName.MaximumLength)
+                                    RTLogLoggerWeak(pLogger, NULL, "%p: %p - %#010RX32 bytes into %.*ls\n",
+                                                    puStack, uPtr, (uint32_t)(uPtr - (uintptr_t)pFound->DllBase),
+                                                    pFound->FullDllName.Length / sizeof(RTUTF16), pFound->FullDllName.Buffer);
+                                else
+                                    RTLogLoggerWeak(pLogger, NULL, "%p: %p - %08RX32 into module at %p\n",
+                                                    puStack, uPtr, (uint32_t)(uPtr - (uintptr_t)pFound->DllBase), pFound->DllBase);
+                            }
+                        }
+
+                        puStack++;
+                    }
+                }
+            }
+
+            /*
+             * Dump the command line if we have one. We do this last in case it crashes.
+             */
+            PRTL_USER_PROCESS_PARAMETERS pProcParams = pPeb->ProcessParameters;
+            if (RT_VALID_PTR(pProcParams))
+            {
+                if (RT_VALID_PTR(pProcParams->CommandLine.Buffer)
+                    && pProcParams->CommandLine.Length > 0
+                    && pProcParams->CommandLine.Length <= pProcParams->CommandLine.MaximumLength
+                    && !(pProcParams->CommandLine.Length & 1)
+                    && !(pProcParams->CommandLine.MaximumLength & 1))
+                    RTLogLoggerWeak(pLogger, NULL, "PEB/CommandLine: %.*ls\n",
+                                    pProcParams->CommandLine.Length / sizeof(RTUTF16), pProcParams->CommandLine.Buffer);
+            }
+        }
+    }
+
+    /*
+     * Do the default stuff, never mind us.
+     */
+    if (g_pfnUnhandledXcptFilter)
+        return g_pfnUnhandledXcptFilter(pPtrs);
+    return EXCEPTION_CONTINUE_SEARCH;
+}
+
diff --git a/src/VBox/Runtime/r3/win/internal-r3-win.h b/src/VBox/Runtime/r3/win/internal-r3-win.h
new file mode 100644
index 00000000..562ac0ed
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/internal-r3-win.h
@@ -0,0 +1,244 @@
+/* $Id: internal-r3-win.h $ */
+/** @file
+ * IPRT - some Windows OS type constants.
+ */
+
+/*
+ * Copyright (C) 2013-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_win_internal_r3_win_h
+#define IPRT_INCLUDED_SRC_r3_win_internal_r3_win_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#include "internal/iprt.h"
+#include <iprt/types.h>
+
+
+/*******************************************************************************
+*   Structures and Typedefs                                                    *
+*******************************************************************************/
+/**
+ * Windows OS type as determined by rtSystemWinOSType().
+ *
+ * @note ASSUMPTIONS are made regarding ordering. Win 9x should come first, then
+ *       NT. The Win9x and NT versions should internally be ordered in ascending
+ *       version/code-base order.
+ */
+typedef enum RTWINOSTYPE
+{
+    kRTWinOSType_UNKNOWN    = 0,
+    kRTWinOSType_9XFIRST    = 1,
+    kRTWinOSType_95         = kRTWinOSType_9XFIRST,
+    kRTWinOSType_95SP1,
+    kRTWinOSType_95OSR2,
+    kRTWinOSType_98,
+    kRTWinOSType_98SP1,
+    kRTWinOSType_98SE,
+    kRTWinOSType_ME,
+    kRTWinOSType_9XLAST     = 99,
+    kRTWinOSType_NTFIRST    = 100,
+    kRTWinOSType_NT310      = kRTWinOSType_NTFIRST,
+    kRTWinOSType_NT350,
+    kRTWinOSType_NT351,
+    kRTWinOSType_NT4,
+    kRTWinOSType_2K,                        /* 5.0 */
+    kRTWinOSType_XP,                        /* 5.1 */
+    kRTWinOSType_XP64,                      /* 5.2, workstation */
+    kRTWinOSType_2003,                      /* 5.2 */
+    kRTWinOSType_VISTA,                     /* 6.0, workstation */
+    kRTWinOSType_2008,                      /* 6.0, server */
+    kRTWinOSType_7,                         /* 6.1, workstation */
+    kRTWinOSType_2008R2,                    /* 6.1, server */
+    kRTWinOSType_8,                         /* 6.2, workstation */
+    kRTWinOSType_2012,                      /* 6.2, server */
+    kRTWinOSType_81,                        /* 6.3, workstation */
+    kRTWinOSType_2012R2,                    /* 6.3, server */
+    kRTWinOSType_10,                        /* 10.0, workstation */
+    kRTWinOSType_2016,                      /* 10.0 1607, server */
+    kRTWinOSType_2019,                      /* 10.0 1809, server */
+    kRTWinOSType_2022,                      /* 10.0 21H2, server */
+    kRTWinOSType_11,                        /* 11.0, workstation */
+    kRTWinOSType_NT_UNKNOWN = 199,
+    kRTWinOSType_NT_LAST    = kRTWinOSType_UNKNOWN
+} RTWINOSTYPE;
+
+/**
+ * Windows loader protection level.
+ */
+typedef enum RTR3WINLDRPROT
+{
+    RTR3WINLDRPROT_INVALID = 0,
+    RTR3WINLDRPROT_NONE,
+    RTR3WINLDRPROT_NO_CWD,
+    RTR3WINLDRPROT_SAFE,
+    RTR3WINLDRPROT_SAFER
+} RTR3WINLDRPROT;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+extern DECL_HIDDEN_DATA(RTR3WINLDRPROT)                 g_enmWinLdrProt;
+extern DECL_HIDDEN_DATA(RTWINOSTYPE)                    g_enmWinVer;
+#ifdef _WINDEF_
+extern DECL_HIDDEN_DATA(OSVERSIONINFOEXW)               g_WinOsInfoEx;
+
+extern DECL_HIDDEN_DATA(HMODULE)                        g_hModKernel32;
+typedef UINT (WINAPI *PFNGETWINSYSDIR)(LPWSTR,UINT);
+extern DECL_HIDDEN_DATA(PFNGETWINSYSDIR)                                g_pfnGetSystemWindowsDirectoryW;
+typedef HANDLE (WINAPI *PFNCREATEWAITABLETIMEREX)(LPSECURITY_ATTRIBUTES, LPCWSTR, DWORD, DWORD);
+extern DECL_HIDDEN_DATA(PFNCREATEWAITABLETIMEREX)                       g_pfnCreateWaitableTimerExW;
+extern DECL_HIDDEN_DATA(decltype(SystemTimeToTzSpecificLocalTime) *)    g_pfnSystemTimeToTzSpecificLocalTime;
+extern DECL_HIDDEN_DATA(decltype(GetHandleInformation) *)               g_pfnGetHandleInformation;
+extern DECL_HIDDEN_DATA(decltype(SetHandleInformation) *)               g_pfnSetHandleInformation;
+extern DECL_HIDDEN_DATA(decltype(IsDebuggerPresent) *)                  g_pfnIsDebuggerPresent;
+extern DECL_HIDDEN_DATA(decltype(GetSystemTimeAsFileTime) *)            g_pfnGetSystemTimeAsFileTime;
+extern DECL_HIDDEN_DATA(decltype(GetProcessAffinityMask) *)             g_pfnGetProcessAffinityMask;
+extern DECL_HIDDEN_DATA(decltype(SetThreadAffinityMask) *)              g_pfnSetThreadAffinityMask;
+extern DECL_HIDDEN_DATA(decltype(CreateIoCompletionPort) *)             g_pfnCreateIoCompletionPort;
+extern DECL_HIDDEN_DATA(decltype(GetQueuedCompletionStatus) *)          g_pfnGetQueuedCompletionStatus;
+extern DECL_HIDDEN_DATA(decltype(PostQueuedCompletionStatus) *)         g_pfnPostQueuedCompletionStatus;
+extern DECL_HIDDEN_DATA(decltype(SetUnhandledExceptionFilter) *)        g_pfnSetUnhandledExceptionFilter;
+extern DECL_HIDDEN_DATA(decltype(UnhandledExceptionFilter) *)           g_pfnUnhandledExceptionFilter;
+extern DECL_HIDDEN_DATA(decltype(IsProcessorFeaturePresent) *)          g_pfnIsProcessorFeaturePresent;
+
+
+extern DECL_HIDDEN_DATA(HMODULE)                        g_hModNtDll;
+typedef NTSTATUS (NTAPI *PFNNTQUERYFULLATTRIBUTESFILE)(struct _OBJECT_ATTRIBUTES *, struct _FILE_NETWORK_OPEN_INFORMATION *);
+extern DECL_HIDDEN_DATA(PFNNTQUERYFULLATTRIBUTESFILE)   g_pfnNtQueryFullAttributesFile;
+typedef NTSTATUS (NTAPI *PFNNTDUPLICATETOKEN)(HANDLE, ACCESS_MASK, struct _OBJECT_ATTRIBUTES *, BOOLEAN, TOKEN_TYPE, PHANDLE);
+extern DECL_HIDDEN_DATA(PFNNTDUPLICATETOKEN)            g_pfnNtDuplicateToken;
+#ifdef IPRT_INCLUDED_nt_nt_h
+extern DECL_HIDDEN_DATA(decltype(NtAlertThread) *)      g_pfnNtAlertThread;
+#endif
+
+extern DECL_HIDDEN_DATA(HMODULE)                        g_hModWinSock;
+
+/** WSAStartup */
+typedef int             (WINAPI *PFNWSASTARTUP)(WORD, struct WSAData *);
+/** WSACleanup */
+typedef int             (WINAPI *PFNWSACLEANUP)(void);
+/** WSAGetLastError */
+typedef int             (WINAPI *PFNWSAGETLASTERROR)(void);
+/** WSASetLastError */
+typedef int             (WINAPI *PFNWSASETLASTERROR)(int);
+/** WSACreateEvent */
+typedef HANDLE          (WINAPI *PFNWSACREATEEVENT)(void);
+/** WSASetEvent */
+typedef BOOL            (WINAPI *PFNWSASETEVENT)(HANDLE);
+/** WSACloseEvent */
+typedef BOOL            (WINAPI *PFNWSACLOSEEVENT)(HANDLE);
+/** WSAEventSelect */
+typedef BOOL            (WINAPI *PFNWSAEVENTSELECT)(UINT_PTR, HANDLE, LONG);
+/** WSAEnumNetworkEvents */
+typedef int             (WINAPI *PFNWSAENUMNETWORKEVENTS)(UINT_PTR, HANDLE, struct _WSANETWORKEVENTS *);
+/** WSASocketW */
+typedef UINT_PTR        (WINAPI *PFNWSASOCKETW)(int, int, int, struct _WSAPROTOCOL_INFOW *, unsigned, DWORD);
+/** WSASend */
+typedef int             (WINAPI *PFNWSASEND)(UINT_PTR, struct _WSABUF *, DWORD, LPDWORD, DWORD dwFlags,
+                                             struct _OVERLAPPED *, uintptr_t /*LPWSAOVERLAPPED_COMPLETION_ROUTINE*/);
+
+/** socket */
+typedef UINT_PTR        (WINAPI *PFNWINSOCKSOCKET)(int, int, int);
+/** closesocket */
+typedef int             (WINAPI *PFNWINSOCKCLOSESOCKET)(UINT_PTR);
+/** recv */
+typedef int             (WINAPI *PFNWINSOCKRECV)(UINT_PTR, char *, int, int);
+/** send */
+typedef int             (WINAPI *PFNWINSOCKSEND)(UINT_PTR, const char *, int, int);
+/** recvfrom */
+typedef int             (WINAPI *PFNWINSOCKRECVFROM)(UINT_PTR, char *, int, int, struct sockaddr *, int *);
+/** sendto */
+typedef int             (WINAPI *PFNWINSOCKSENDTO)(UINT_PTR, const char *, int, int, const struct sockaddr *, int);
+/** bind */
+typedef int             (WINAPI *PFNWINSOCKBIND)(UINT_PTR, const struct sockaddr *, int);
+/** listen  */
+typedef int             (WINAPI *PFNWINSOCKLISTEN)(UINT_PTR, int);
+/** accept */
+typedef UINT_PTR        (WINAPI *PFNWINSOCKACCEPT)(UINT_PTR, struct sockaddr *, int *);
+/** connect */
+typedef int             (WINAPI *PFNWINSOCKCONNECT)(UINT_PTR, const struct sockaddr *, int);
+/** shutdown */
+typedef int             (WINAPI *PFNWINSOCKSHUTDOWN)(UINT_PTR, int);
+/** getsockopt */
+typedef int             (WINAPI *PFNWINSOCKGETSOCKOPT)(UINT_PTR, int, int, char *, int *);
+/** setsockopt */
+typedef int             (WINAPI *PFNWINSOCKSETSOCKOPT)(UINT_PTR, int, int, const char *, int);
+/** ioctlsocket */
+typedef int             (WINAPI *PFNWINSOCKIOCTLSOCKET)(UINT_PTR, long, unsigned long *);
+/** getpeername   */
+typedef int             (WINAPI *PFNWINSOCKGETPEERNAME)(UINT_PTR, struct sockaddr *, int *);
+/** getsockname */
+typedef int             (WINAPI *PFNWINSOCKGETSOCKNAME)(UINT_PTR, struct sockaddr *, int *);
+/** __WSAFDIsSet */
+typedef int             (WINAPI *PFNWINSOCK__WSAFDISSET)(UINT_PTR, struct fd_set *);
+/** select */
+typedef int             (WINAPI *PFNWINSOCKSELECT)(int, struct fd_set *, struct fd_set *, struct fd_set *, const struct timeval *);
+/** gethostbyname */
+typedef struct hostent *(WINAPI *PFNWINSOCKGETHOSTBYNAME)(const char *);
+
+extern DECL_HIDDEN_DATA(PFNWSASTARTUP)                   g_pfnWSAStartup;
+extern DECL_HIDDEN_DATA(PFNWSACLEANUP)                   g_pfnWSACleanup;
+extern DECL_HIDDEN_DATA(PFNWSAGETLASTERROR)              g_pfnWSAGetLastError;
+extern DECL_HIDDEN_DATA(PFNWSASETLASTERROR)              g_pfnWSASetLastError;
+extern DECL_HIDDEN_DATA(PFNWSACREATEEVENT)               g_pfnWSACreateEvent;
+extern DECL_HIDDEN_DATA(PFNWSACLOSEEVENT)                g_pfnWSACloseEvent;
+extern DECL_HIDDEN_DATA(PFNWSASETEVENT)                  g_pfnWSASetEvent;
+extern DECL_HIDDEN_DATA(PFNWSAEVENTSELECT)               g_pfnWSAEventSelect;
+extern DECL_HIDDEN_DATA(PFNWSAENUMNETWORKEVENTS)         g_pfnWSAEnumNetworkEvents;
+extern DECL_HIDDEN_DATA(PFNWSASOCKETW)                   g_pfnWSASocketW;
+extern DECL_HIDDEN_DATA(PFNWSASEND)                      g_pfnWSASend;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSOCKET)                g_pfnsocket;
+extern DECL_HIDDEN_DATA(PFNWINSOCKCLOSESOCKET)           g_pfnclosesocket;
+extern DECL_HIDDEN_DATA(PFNWINSOCKRECV)                  g_pfnrecv;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSEND)                  g_pfnsend;
+extern DECL_HIDDEN_DATA(PFNWINSOCKRECVFROM)              g_pfnrecvfrom;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSENDTO)                g_pfnsendto;
+extern DECL_HIDDEN_DATA(PFNWINSOCKBIND)                  g_pfnbind;
+extern DECL_HIDDEN_DATA(PFNWINSOCKLISTEN)                g_pfnlisten;
+extern DECL_HIDDEN_DATA(PFNWINSOCKACCEPT)                g_pfnaccept;
+extern DECL_HIDDEN_DATA(PFNWINSOCKCONNECT)               g_pfnconnect;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSHUTDOWN)              g_pfnshutdown;
+extern DECL_HIDDEN_DATA(PFNWINSOCKGETSOCKOPT)            g_pfngetsockopt;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSETSOCKOPT)            g_pfnsetsockopt;
+extern DECL_HIDDEN_DATA(PFNWINSOCKIOCTLSOCKET)           g_pfnioctlsocket;
+extern DECL_HIDDEN_DATA(PFNWINSOCKGETPEERNAME)           g_pfngetpeername;
+extern DECL_HIDDEN_DATA(PFNWINSOCKGETSOCKNAME)           g_pfngetsockname;
+extern DECL_HIDDEN_DATA(PFNWINSOCK__WSAFDISSET)          g_pfn__WSAFDIsSet;
+extern DECL_HIDDEN_DATA(PFNWINSOCKSELECT)                g_pfnselect;
+extern DECL_HIDDEN_DATA(PFNWINSOCKGETHOSTBYNAME)         g_pfngethostbyname;
+#endif
+
+
+#endif /* !IPRT_INCLUDED_SRC_r3_win_internal_r3_win_h */
+
diff --git a/src/VBox/Runtime/r3/win/krnlmod-win.cpp b/src/VBox/Runtime/r3/win/krnlmod-win.cpp
new file mode 100644
index 00000000..255cc2cf
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/krnlmod-win.cpp
@@ -0,0 +1,331 @@
+/* $Id: krnlmod-win.cpp $ */
+/** @file
+ * IPRT - Kernel module, Windows.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/nt/nt.h>
+
+#include <iprt/krnlmod.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/dir.h>
+#include <iprt/errcore.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/types.h>
+
+
+/**
+ * Internal kernel information record state.
+ */
+typedef struct RTKRNLMODINFOINT
+{
+    /** Reference counter. */
+    volatile uint32_t   cRefs;
+    /** Reference count for the kernel module. */
+    uint32_t            cRefKrnlMod;
+    /** Load address of the kernel module. */
+    RTR0UINTPTR         uLoadAddr;
+    /** Size of the kernel module. */
+    size_t              cbKrnlMod;
+    /** Pointer to the driver name. */
+    const char          *pszName;
+    /** Size of the name in characters including the zero terminator. */
+    size_t              cchFilePath;
+    /** Module name - variable in size. */
+    char                achFilePath[1];
+} RTKRNLMODINFOINT;
+/** Pointer to the internal kernel module information record. */
+typedef RTKRNLMODINFOINT *PRTKRNLMODINFOINT;
+/** Pointer to a const internal kernel module information record. */
+typedef const RTKRNLMODINFOINT *PCRTKRNLMODINFOINT;
+
+
+/**
+ * Destroy the given kernel module information record.
+ *
+ * @param   pThis            The record to destroy.
+ */
+static void rtKrnlModInfoDestroy(PRTKRNLMODINFOINT pThis)
+{
+    RTMemFree(pThis);
+}
+
+
+/**
+ * Queries the complete kernel modules structure and returns a pointer to it.
+ *
+ * @returns IPRT status code.
+ * @param   ppKrnlMods       Where to store the pointer to the kernel module list on success.
+ *                           Free with RTMemFree().
+ */
+static int rtKrnlModWinQueryKrnlMods(PRTL_PROCESS_MODULES *ppKrnlMods)
+{
+    int rc = VINF_SUCCESS;
+    RTL_PROCESS_MODULES KrnlModsSize;
+
+    NTSTATUS rcNt = NtQuerySystemInformation(SystemModuleInformation, &KrnlModsSize, sizeof(KrnlModsSize), NULL);
+    if (NT_SUCCESS(rcNt) || rcNt == STATUS_INFO_LENGTH_MISMATCH)
+    {
+        ULONG cbKrnlMods = RT_UOFFSETOF_DYN(RTL_PROCESS_MODULES, Modules[KrnlModsSize.NumberOfModules]);
+        PRTL_PROCESS_MODULES pKrnlMods = (PRTL_PROCESS_MODULES)RTMemAllocZ(cbKrnlMods);
+        if (RT_LIKELY(pKrnlMods))
+        {
+            rcNt = NtQuerySystemInformation(SystemModuleInformation, pKrnlMods, cbKrnlMods, NULL);
+            if (NT_SUCCESS(rcNt))
+                *ppKrnlMods = pKrnlMods;
+            else
+                rc = RTErrConvertFromNtStatus(rcNt);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    else
+        rc = RTErrConvertFromNtStatus(rcNt);
+
+    return rc;
+}
+
+/**
+ * Creates a new kernel module information record for the given module.
+ *
+ * @returns IPRT status code.
+ * @param   pModInfo         The kernel module information.
+ * @param   phKrnlModInfo    Where to store the handle to the kernel module information record
+ *                           on success.
+ */
+static int rtKrnlModWinInfoCreate(PRTL_PROCESS_MODULE_INFORMATION pModInfo, PRTKRNLMODINFO phKrnlModInfo)
+{
+    int rc = VINF_SUCCESS;
+    RT_NOREF2(pModInfo, phKrnlModInfo);
+    size_t cchFilePath = strlen((const char *)&pModInfo->FullPathName[0]) + 1;
+    PRTKRNLMODINFOINT pThis = (PRTKRNLMODINFOINT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTKRNLMODINFOINT, achFilePath[cchFilePath]));
+    if (RT_LIKELY(pThis))
+    {
+        memcpy(&pThis->achFilePath[0], &pModInfo->FullPathName[0], cchFilePath);
+        pThis->cchFilePath = cchFilePath;
+        pThis->cRefs       = 1;
+        pThis->cbKrnlMod   = pModInfo->ImageSize;
+        pThis->uLoadAddr   = (RTR0UINTPTR)pModInfo->ImageBase;
+        pThis->pszName     =   pModInfo->OffsetToFileName >= cchFilePath
+                             ? NULL
+                             : pThis->achFilePath + pModInfo->OffsetToFileName;
+
+        *phKrnlModInfo = pThis;
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModQueryLoaded(const char *pszName, bool *pfLoaded)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfLoaded, VERR_INVALID_POINTER);
+
+    int rc = VERR_NOT_IMPLEMENTED;
+
+    return rc;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfo(const char *pszName, PRTKRNLMODINFO phKrnlModInfo)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertPtrReturn(phKrnlModInfo, VERR_INVALID_POINTER);
+
+    int rc = VERR_NOT_IMPLEMENTED;
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModLoadedGetCount(void)
+{
+    uint32_t cKrnlMods = 0;
+    RTL_PROCESS_MODULES ProcMods;
+
+    NTSTATUS rcNt = NtQuerySystemInformation(SystemModuleInformation, &ProcMods, sizeof(ProcMods), NULL);
+    if (NT_SUCCESS(rcNt) || rcNt == STATUS_INFO_LENGTH_MISMATCH)
+        cKrnlMods = ProcMods.NumberOfModules;
+
+    return cKrnlMods;
+}
+
+
+RTDECL(int) RTKrnlModLoadedQueryInfoAll(PRTKRNLMODINFO pahKrnlModInfo, uint32_t cEntriesMax,
+                                        uint32_t *pcEntries)
+{
+    if (cEntriesMax > 0)
+        AssertPtrReturn(pahKrnlModInfo, VERR_INVALID_POINTER);
+
+    PRTL_PROCESS_MODULES pKrnlMods = NULL;
+    int rc = rtKrnlModWinQueryKrnlMods(&pKrnlMods);
+    if (RT_SUCCESS(rc))
+    {
+        if (pKrnlMods->NumberOfModules <= cEntriesMax)
+        {
+            for (unsigned i = 0; i < pKrnlMods->NumberOfModules; i++)
+            {
+                pKrnlMods->Modules[i].FullPathName[255] = '\0'; /* Paranoia */
+                rc = rtKrnlModWinInfoCreate(&pKrnlMods->Modules[i], &pahKrnlModInfo[i]);
+                if (RT_FAILURE(rc))
+                {
+                    while (i-- > 0)
+                        RTKrnlModInfoRelease(pahKrnlModInfo[i]);
+                    break;
+                }
+            }
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+
+        if (pcEntries)
+            *pcEntries = pKrnlMods->NumberOfModules;
+
+        RTMemFree(pKrnlMods);
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRetain(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoRelease(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    if (!pThis)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtKrnlModInfoDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTKrnlModInfoGetRefCnt(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cRefKrnlMod;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetName(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return pThis->pszName;
+}
+
+
+RTDECL(const char *) RTKrnlModInfoGetFilePath(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, NULL);
+
+    return &pThis->achFilePath[0];
+}
+
+
+RTDECL(size_t) RTKrnlModInfoGetSize(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cbKrnlMod;
+}
+
+
+RTDECL(RTR0UINTPTR) RTKrnlModInfoGetLoadAddr(RTKRNLMODINFO hKrnlModInfo)
+{
+    PRTKRNLMODINFOINT pThis = hKrnlModInfo;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->uLoadAddr;
+}
+
+
+RTDECL(int) RTKrnlModInfoQueryRefModInfo(RTKRNLMODINFO hKrnlModInfo, uint32_t idx,
+                                         PRTKRNLMODINFO phKrnlModInfoRef)
+{
+    RT_NOREF3(hKrnlModInfo, idx, phKrnlModInfoRef);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModLoadByPath(const char *pszPath)
+{
+    AssertPtrReturn(pszPath, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTKrnlModUnloadByName(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
diff --git a/src/VBox/Runtime/r3/win/ldrNative-win.cpp b/src/VBox/Runtime/r3/win/ldrNative-win.cpp
new file mode 100644
index 00000000..2ff98a4c
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/ldrNative-win.cpp
@@ -0,0 +1,326 @@
+/* $Id: ldrNative-win.cpp $ */
+/** @file
+ * IPRT - Binary Image Loader, Win32 native.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_LDR
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/ldr.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/log.h>
+#include <iprt/once.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include "internal/ldr.h"
+#include "internal-r3-win.h"
+
+#ifndef LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR
+# define LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR       UINT32_C(0x100)
+# define LOAD_LIBRARY_SEARCH_APPLICATION_DIR    UINT32_C(0x200)
+# define LOAD_LIBRARY_SEARCH_SYSTEM32           UINT32_C(0x800)
+#endif
+
+
+DECLHIDDEN(int) rtldrNativeLoad(const char *pszFilename, uintptr_t *phHandle, uint32_t fFlags, PRTERRINFO pErrInfo)
+{
+    Assert(sizeof(*phHandle) >= sizeof(HMODULE));
+    AssertReturn(!(fFlags & RTLDRLOAD_FLAGS_GLOBAL), VERR_INVALID_FLAGS);
+    AssertLogRelMsgReturn(RTPathStartsWithRoot(pszFilename),  /* Relative names will still be applied to the search path. */
+                          ("pszFilename='%s'\n", pszFilename),
+                          VERR_INTERNAL_ERROR_2);
+    AssertReleaseMsg(g_hModKernel32,
+                     ("rtldrNativeLoad(%s,,) is called before IPRT has configured the windows loader!\n", pszFilename));
+
+    /*
+     * Convert to UTF-16 and make sure it got a .DLL suffix.
+     */
+    /** @todo Implement long path support for native DLL loading on windows. @bugref{9248} */
+    int rc;
+    RTUTF16 *pwszNative = NULL;
+    if (RTPathHasSuffix(pszFilename) || (fFlags & RTLDRLOAD_FLAGS_NO_SUFFIX))
+        rc = RTStrToUtf16(pszFilename, &pwszNative);
+    else
+    {
+        size_t cwcAlloc;
+        rc = RTStrCalcUtf16LenEx(pszFilename, RTSTR_MAX, &cwcAlloc);
+        if (RT_SUCCESS(rc))
+        {
+            cwcAlloc += sizeof(".DLL");
+            pwszNative = RTUtf16Alloc(cwcAlloc * sizeof(RTUTF16));
+            if (pwszNative)
+            {
+                size_t cwcNative;
+                rc = RTStrToUtf16Ex(pszFilename, RTSTR_MAX, &pwszNative, cwcAlloc, &cwcNative);
+                if (RT_SUCCESS(rc))
+                    rc = RTUtf16CopyAscii(&pwszNative[cwcNative], cwcAlloc - cwcNative, ".DLL");
+            }
+            else
+                rc = VERR_NO_UTF16_MEMORY;
+        }
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /* Convert slashes just to be on the safe side. */
+        for (size_t off = 0;; off++)
+        {
+            RTUTF16 wc = pwszNative[off];
+            if (wc == '/')
+                pwszNative[off] = '\\';
+            else if (!wc)
+                break;
+        }
+
+        /*
+         * Attempt load.
+         */
+        HMODULE     hmod;
+        static int  s_iSearchDllLoadDirSupported = 0;
+        if (   !(fFlags & RTLDRLOAD_FLAGS_NT_SEARCH_DLL_LOAD_DIR)
+            || s_iSearchDllLoadDirSupported < 0)
+            hmod = LoadLibraryExW(pwszNative, NULL, 0);
+        else
+        {
+            hmod = LoadLibraryExW(pwszNative, NULL, LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32
+                                  | LOAD_LIBRARY_SEARCH_APPLICATION_DIR);
+            if (s_iSearchDllLoadDirSupported == 0)
+            {
+                if (hmod != NULL || GetLastError() != ERROR_INVALID_PARAMETER)
+                    s_iSearchDllLoadDirSupported = 1;
+                else
+                {
+                    s_iSearchDllLoadDirSupported = -1;
+                    hmod = LoadLibraryExW(pwszNative, NULL, 0);
+                }
+            }
+        }
+        if (hmod)
+        {
+            *phHandle = (uintptr_t)hmod;
+            RTUtf16Free(pwszNative);
+            return VINF_SUCCESS;
+        }
+
+        /*
+         * Try figure why it failed to load.
+         */
+        DWORD dwErr = GetLastError();
+        rc = RTErrConvertFromWin32(dwErr);
+        rc = RTErrInfoSetF(pErrInfo, rc, "GetLastError=%u", dwErr);
+    }
+    else
+        rc = RTErrInfoSetF(pErrInfo, rc, "Error converting UTF-8 to UTF-16 string.");
+    RTUtf16Free(pwszNative);
+    return rc;
+}
+
+
+DECLCALLBACK(int) rtldrNativeGetSymbol(PRTLDRMODINTERNAL pMod, const char *pszSymbol, void **ppvValue)
+{
+    PRTLDRMODNATIVE pModNative = (PRTLDRMODNATIVE)pMod;
+    FARPROC pfn = GetProcAddress((HMODULE)pModNative->hNative, pszSymbol);
+    if (pfn)
+    {
+        *ppvValue = (void *)pfn;
+        return VINF_SUCCESS;
+    }
+    *ppvValue = NULL;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+DECLCALLBACK(int) rtldrNativeClose(PRTLDRMODINTERNAL pMod)
+{
+    PRTLDRMODNATIVE pModNative = (PRTLDRMODNATIVE)pMod;
+    if (   (pModNative->fFlags & RTLDRLOAD_FLAGS_NO_UNLOAD)
+        || FreeLibrary((HMODULE)pModNative->hNative))
+    {
+        pModNative->hNative = (uintptr_t)INVALID_HANDLE_VALUE;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+DECLHIDDEN(int) rtldrNativeLoadSystem(const char *pszFilename, const char *pszExt, uint32_t fFlags, PRTLDRMOD phLdrMod)
+{
+    AssertReleaseMsg(g_hModKernel32,
+                     ("rtldrNativeLoadSystem(%s,,) is called before IPRT has configured the windows loader!\n", pszFilename));
+
+    /*
+     * Resolve side-by-side resolver API.
+     */
+    static bool volatile s_fInitialized = false;
+    static decltype(RtlDosApplyFileIsolationRedirection_Ustr) *s_pfnApplyRedir = NULL;
+    if (!s_fInitialized)
+    {
+        s_pfnApplyRedir = (decltype(s_pfnApplyRedir))GetProcAddress(g_hModNtDll,
+                                                                    "RtlDosApplyFileIsolationRedirection_Ustr");
+        ASMCompilerBarrier();
+        s_fInitialized = true;
+    }
+
+    /*
+     * We try WinSxS via undocumented NTDLL API and flal back on the System32
+     * directory. No other locations are supported.
+     */
+    int rc = VERR_TRY_AGAIN;
+    char  szPath[RTPATH_MAX];
+    char *pszPath = szPath;
+
+    /* Get the windows system32 directory so we can sanity check the WinSxS result. */
+    WCHAR wszSysDir[MAX_PATH];
+    UINT cwcSysDir = GetSystemDirectoryW(wszSysDir, MAX_PATH);
+    if (cwcSysDir >= MAX_PATH)
+        return VERR_FILENAME_TOO_LONG;
+
+    /* Try side-by-side first (see COMCTL32.DLL). */
+    if (s_pfnApplyRedir)
+    {
+        size_t   cwcName = 0;
+        RTUTF16  wszName[MAX_PATH];
+        PRTUTF16 pwszName = wszName;
+        int rc2 = RTStrToUtf16Ex(pszFilename, RTSTR_MAX, &pwszName, RT_ELEMENTS(wszName), &cwcName);
+        if (RT_SUCCESS(rc2))
+        {
+            static UNICODE_STRING const s_DefaultSuffix = RTNT_CONSTANT_UNISTR(L".dll");
+            WCHAR           wszPath[MAX_PATH];
+            UNICODE_STRING  UniStrStatic   = { 0, (USHORT)sizeof(wszPath) - sizeof(WCHAR), wszPath };
+            UNICODE_STRING  UniStrDynamic  = { 0, 0, NULL };
+            PUNICODE_STRING pUniStrResult  = NULL;
+            UNICODE_STRING  UniStrName     =
+            { (USHORT)(cwcName * sizeof(RTUTF16)), (USHORT)((cwcName + 1) * sizeof(RTUTF16)), wszName };
+
+            NTSTATUS rcNt = s_pfnApplyRedir(1 /*fFlags*/,
+                                            &UniStrName,
+                                            (PUNICODE_STRING)&s_DefaultSuffix,
+                                            &UniStrStatic,
+                                            &UniStrDynamic,
+                                            &pUniStrResult,
+                                            NULL /*pNewFlags*/,
+                                            NULL /*pcbFilename*/,
+                                            NULL /*pcbNeeded*/);
+            if (NT_SUCCESS(rcNt))
+            {
+                /*
+                 * Check that the resolved path has similarities to the
+                 * system directory.
+                 *
+                 * ASSUMES the windows directory is a root directory and
+                 * that both System32 and are on the same level.  So, we'll
+                 * have 2 matching components (or more if the resolver
+                 * returns a system32 path for some reason).
+                 */
+                unsigned cMatchingComponents = 0;
+                size_t   off = 0;
+                while (off < pUniStrResult->Length)
+                {
+                    RTUTF16 wc1 = wszSysDir[off];
+                    RTUTF16 wc2 = pUniStrResult->Buffer[off];
+                    if (!RTPATH_IS_SLASH(wc1))
+                    {
+                        if (wc1 == wc2)
+                            off++;
+                        else if (   wc1 < 127
+                                 && wc2 < 127
+                                 && RT_C_TO_LOWER(wc1) == RT_C_TO_LOWER(wc2) )
+                            off++;
+                        else
+                            break;
+                    }
+                    else if (RTPATH_IS_SLASH(wc2))
+                    {
+                        cMatchingComponents += off > 0;
+                        do
+                            off++;
+                        while (   off < pUniStrResult->Length
+                               && RTPATH_IS_SLASH(wszSysDir[off])
+                               && RTPATH_IS_SLASH(pUniStrResult->Buffer[off]));
+                    }
+                    else
+                        break;
+                }
+                if (cMatchingComponents >= 2)
+                {
+                    pszPath = szPath;
+                    rc2 = RTUtf16ToUtf8Ex(pUniStrResult->Buffer, pUniStrResult->Length / sizeof(RTUTF16),
+                                          &pszPath, sizeof(szPath), NULL);
+                    if (RT_SUCCESS(rc2))
+                        rc = VINF_SUCCESS;
+                }
+                else
+                    AssertMsgFailed(("%s -> '%*.ls'\n", pszFilename, pUniStrResult->Length, pUniStrResult->Buffer));
+                RtlFreeUnicodeString(&UniStrDynamic);
+            }
+        }
+        else
+            AssertMsgFailed(("%Rrc\n", rc));
+    }
+
+    /* If the above didn't succeed, create a system32 path. */
+    if (RT_FAILURE(rc))
+    {
+        rc = RTUtf16ToUtf8Ex(wszSysDir, RTSTR_MAX, &pszPath, sizeof(szPath), NULL);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTPathAppend(szPath, sizeof(szPath), pszFilename);
+            if (pszExt && RT_SUCCESS(rc))
+                rc = RTStrCat(szPath, sizeof(szPath), pszExt);
+        }
+    }
+
+    /* Do the actual loading, if we were successful constructing a name. */
+    if (RT_SUCCESS(rc))
+    {
+        if (RTFileExists(szPath))
+            rc = RTLdrLoadEx(szPath, phLdrMod, fFlags, NULL);
+        else
+            rc = VERR_MODULE_NOT_FOUND;
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/localipc-win.cpp b/src/VBox/Runtime/r3/win/localipc-win.cpp
new file mode 100644
index 00000000..6d56ab91
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/localipc-win.cpp
@@ -0,0 +1,1778 @@
+/* $Id: localipc-win.cpp $ */
+/** @file
+ * IPRT - Local IPC, Windows Implementation Using Named Pipes.
+ *
+ * @note This code only works on W2K because of the dependency on
+ *       ConvertStringSecurityDescriptorToSecurityDescriptor.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_LOCALIPC
+#include <iprt/nt/nt-and-windows.h> /* Need NtCancelIoFile and a few Rtl functions. */
+#include <sddl.h>
+#include <aclapi.h>
+
+#include "internal/iprt.h"
+#include <iprt/localipc.h>
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include <iprt/utf16.h>
+
+#include "internal/magics.h"
+#include "internal-r3-win.h"
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Pipe prefix string. */
+#define RTLOCALIPC_WIN_PREFIX   L"\\\\.\\pipe\\IPRT-"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Local IPC service instance, Windows.
+ */
+typedef struct RTLOCALIPCSERVERINT
+{
+    /** The magic (RTLOCALIPCSERVER_MAGIC). */
+    uint32_t u32Magic;
+    /** The creation flags. */
+    uint32_t fFlags;
+    /** Critical section protecting the structure. */
+    RTCRITSECT CritSect;
+    /** The number of references to the instance.
+     * @remarks The reference counting isn't race proof. */
+    uint32_t volatile cRefs;
+    /** Indicates that there is a pending cancel request. */
+    bool volatile fCancelled;
+    /** The named pipe handle. */
+    HANDLE hNmPipe;
+    /** The handle to the event object we're using for overlapped I/O. */
+    HANDLE hEvent;
+    /** The overlapped I/O structure. */
+    OVERLAPPED OverlappedIO;
+    /** The full pipe name (variable length). */
+    RTUTF16 wszName[1];
+} RTLOCALIPCSERVERINT;
+/** Pointer to a local IPC server instance (Windows). */
+typedef RTLOCALIPCSERVERINT *PRTLOCALIPCSERVERINT;
+
+
+/**
+ * Local IPC session instance, Windows.
+ *
+ * This is a named pipe and we should probably merge the pipe code with this to
+ * save work and code duplication.
+ */
+typedef struct RTLOCALIPCSESSIONINT
+{
+    /** The magic (RTLOCALIPCSESSION_MAGIC). */
+    uint32_t            u32Magic;
+    /** Critical section protecting the structure. */
+    RTCRITSECT          CritSect;
+    /** The number of references to the instance.
+     * @remarks The reference counting isn't race proof. */
+    uint32_t volatile   cRefs;
+    /** Set if the zero byte read that the poll code using is pending. */
+    bool                fZeroByteRead;
+    /** Indicates that there is a pending cancel request. */
+    bool volatile       fCancelled;
+    /** Set if this is the server side, clear if the client. */
+    bool                fServerSide;
+    /** The named pipe handle. */
+    HANDLE              hNmPipe;
+    struct
+    {
+        RTTHREAD        hActiveThread;
+        /** The handle to the event object we're using for overlapped I/O. */
+        HANDLE          hEvent;
+        /** The overlapped I/O structure. */
+        OVERLAPPED      OverlappedIO;
+    }
+    /** Overlapped reads. */
+                        Read,
+    /** Overlapped writes. */
+                        Write;
+#if 0 /* Non-blocking writes are not yet supported. */
+    /** Bounce buffer for writes. */
+    uint8_t            *pbBounceBuf;
+    /** Amount of used buffer space. */
+    size_t              cbBounceBufUsed;
+    /** Amount of allocated buffer space. */
+    size_t              cbBounceBufAlloc;
+#endif
+    /** Buffer for the zero byte read.
+     * Used in RTLocalIpcSessionWaitForData(). */
+    uint8_t             abBuf[8];
+} RTLOCALIPCSESSIONINT;
+/** Pointer to a local IPC session instance (Windows). */
+typedef RTLOCALIPCSESSIONINT *PRTLOCALIPCSESSIONINT;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static int rtLocalIpcWinCreateSession(PRTLOCALIPCSESSIONINT *ppSession, HANDLE hNmPipeSession);
+
+
+/**
+ * DACL for block all network access and local users other than the creator/owner.
+ *
+ * ACE format: (ace_type;ace_flags;rights;object_guid;inherit_object_guid;account_sid)
+ *
+ * Note! FILE_GENERIC_WRITE (SDDL_FILE_WRITE) is evil here because it includes
+ *       the FILE_CREATE_PIPE_INSTANCE(=FILE_APPEND_DATA) flag. Thus the hardcoded
+ *       value 0x0012019b in the client ACE. The server-side still needs
+ *       setting FILE_CREATE_PIPE_INSTANCE although.
+ *       It expands to:
+ *          0x00000001 - FILE_READ_DATA
+ *          0x00000008 - FILE_READ_EA
+ *          0x00000080 - FILE_READ_ATTRIBUTES
+ *          0x00020000 - READ_CONTROL
+ *          0x00100000 - SYNCHRONIZE
+ *          0x00000002 - FILE_WRITE_DATA
+ *          0x00000010 - FILE_WRITE_EA
+ *          0x00000100 - FILE_WRITE_ATTRIBUTES
+ *       =  0x0012019b (client)
+ *       + (only for server):
+ *          0x00000004 - FILE_CREATE_PIPE_INSTANCE
+ *       =  0x0012019f
+ *
+ * @todo Triple check this!
+ * @todo EVERYONE -> AUTHENTICATED USERS or something more appropriate?
+ * @todo Have trouble allowing the owner FILE_CREATE_PIPE_INSTANCE access, so for now I'm hacking
+ *       it just to get progress - the service runs as local system.
+ *       The CREATOR OWNER and PERSONAL SELF works (the former is only involved in inheriting
+ *       it seems, which is why it won't work. The latter I've no idea about. Perhaps the solution
+ *       is to go the annoying route of OpenProcessToken, QueryTokenInformation,
+ *          ConvertSidToStringSid and then use the result... Suggestions are very welcome
+ */
+#define RTLOCALIPC_WIN_SDDL_BASE \
+        SDDL_DACL SDDL_DELIMINATOR \
+        SDDL_ACE_BEGIN SDDL_ACCESS_DENIED L";;" SDDL_GENERIC_ALL L";;;" SDDL_NETWORK SDDL_ACE_END \
+        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" SDDL_FILE_ALL   L";;;" SDDL_LOCAL_SYSTEM SDDL_ACE_END
+#define RTLOCALIPC_WIN_SDDL_SERVER \
+        RTLOCALIPC_WIN_SDDL_BASE \
+        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" L"0x0012019f"   L";;;" SDDL_EVERYONE SDDL_ACE_END
+#define RTLOCALIPC_WIN_SDDL_CLIENT \
+        RTLOCALIPC_WIN_SDDL_BASE \
+        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" L"0x0012019b"   L";;;" SDDL_EVERYONE SDDL_ACE_END
+static NTSTATUS rtLocalIpcBuildDacl(PACL pDacl, bool fServer)
+{
+    static SID_IDENTIFIER_AUTHORITY s_NtAuth    = SECURITY_NT_AUTHORITY;
+    static SID_IDENTIFIER_AUTHORITY s_WorldAuth = SECURITY_WORLD_SID_AUTHORITY;
+    union
+    {
+        SID     Sid;
+        uint8_t abPadding[SECURITY_MAX_SID_SIZE];
+    } Network, LocalSystem, Everyone;
+
+
+    /* 1. SDDL_ACCESS_DENIED L";;" SDDL_GENERIC_ALL L";;;" SDDL_NETWORK */
+    NTSTATUS rcNt = RtlInitializeSid(&Network.Sid, &s_NtAuth, 1);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+    *RtlSubAuthoritySid(&Network.Sid, 0) = SECURITY_NETWORK_RID;
+
+    rcNt = RtlAddAccessDeniedAce(pDacl, ACL_REVISION, GENERIC_ALL, &Network.Sid);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+
+    /* 2. SDDL_ACCESS_ALLOWED L";;" SDDL_FILE_ALL   L";;;" SDDL_LOCAL_SYSTEM */
+    rcNt = RtlInitializeSid(&LocalSystem.Sid, &s_NtAuth, 1);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+    *RtlSubAuthoritySid(&LocalSystem.Sid, 0) = SECURITY_LOCAL_SYSTEM_RID;
+
+    rcNt = RtlAddAccessAllowedAce(pDacl, ACL_REVISION, FILE_ALL_ACCESS, &Network.Sid);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+
+
+    /* 3. server: SDDL_ACCESS_ALLOWED L";;" L"0x0012019f"   L";;;" SDDL_EVERYONE
+          client: SDDL_ACCESS_ALLOWED L";;" L"0x0012019b"   L";;;" SDDL_EVERYONE */
+    rcNt = RtlInitializeSid(&Everyone.Sid, &s_NtAuth, 1);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+    *RtlSubAuthoritySid(&Everyone.Sid, 0) = SECURITY_WORLD_RID;
+
+    DWORD const fAccess = FILE_READ_DATA                       /* 0x00000001 */
+                        | FILE_WRITE_DATA                      /* 0x00000002 */
+                        | FILE_CREATE_PIPE_INSTANCE * fServer  /* 0x00000004 */
+                        | FILE_READ_EA                         /* 0x00000008 */
+                        | FILE_WRITE_EA                        /* 0x00000010 */
+                        | FILE_READ_ATTRIBUTES                 /* 0x00000080 */
+                        | FILE_WRITE_ATTRIBUTES                /* 0x00000100 */
+                        | READ_CONTROL                         /* 0x00020000 */
+                        | SYNCHRONIZE;                         /* 0x00100000*/
+    Assert(fAccess == (fServer ? 0x0012019fU : 0x0012019bU));
+
+    rcNt = RtlAddAccessAllowedAce(pDacl, ACL_REVISION, fAccess, &Network.Sid);
+    AssertReturn(NT_SUCCESS(rcNt), rcNt);
+
+    return true;
+}
+
+
+/**
+ * Builds and allocates the security descriptor required for securing the local pipe.
+ *
+ * @return  IPRT status code.
+ * @param   ppDesc              Where to store the allocated security descriptor on success.
+ *                              Must be free'd using LocalFree().
+ * @param   fServer             Whether it's for a server or client instance.
+ */
+static int rtLocalIpcServerWinAllocSecurityDescriptor(PSECURITY_DESCRIPTOR *ppDesc, bool fServer)
+{
+    int rc;
+    PSECURITY_DESCRIPTOR pSecDesc = NULL;
+
+#if 0
+    /*
+     * Resolve the API the first time around.
+     */
+    static bool volatile s_fResolvedApis = false;
+    /** advapi32.dll API ConvertStringSecurityDescriptorToSecurityDescriptorW. */
+    static decltype(ConvertStringSecurityDescriptorToSecurityDescriptorW) *s_pfnSSDLToSecDescW = NULL;
+
+    if (!s_fResolvedApis)
+    {
+        s_pfnSSDLToSecDescW
+            = (decltype(s_pfnSSDLToSecDescW))RTLdrGetSystemSymbol("advapi32.dll",
+                                                                  "ConvertStringSecurityDescriptorToSecurityDescriptorW");
+        ASMCompilerBarrier();
+        s_fResolvedApis = true;
+    }
+    if (s_pfnSSDLToSecDescW)
+    {
+        /*
+         * We'll create a security descriptor from a SDDL that denies
+         * access to network clients (this is local IPC after all), it
+         * makes some further restrictions to prevent non-authenticated
+         * users from screwing around.
+         */
+        PCRTUTF16 pwszSDDL  = fServer ? RTLOCALIPC_WIN_SDDL_SERVER : RTLOCALIPC_WIN_SDDL_CLIENT;
+        ULONG     cbSecDesc = 0;
+        SetLastError(0);
+        if (s_pfnSSDLToSecDescW(pwszSDDL, SDDL_REVISION_1, &pSecDesc, &cbSecDesc))
+        {
+            DWORD dwErr = GetLastError(); RT_NOREF(dwErr);
+            AssertPtr(pSecDesc);
+            *ppDesc = pSecDesc;
+            return VINF_SUCCESS;
+        }
+
+        rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+#endif
+    {
+        /*
+         * Manually construct the descriptor.
+         *
+         * This is a bit crude. The 8KB is probably 50+ times more than what we need.
+         */
+        uint32_t const cbAlloc = SECURITY_DESCRIPTOR_MIN_LENGTH * 2 + _8K;
+        pSecDesc = LocalAlloc(LMEM_FIXED, cbAlloc);
+        if (!pSecDesc)
+            return VERR_NO_MEMORY;
+        RT_BZERO(pSecDesc, cbAlloc);
+
+        uint32_t const cbDacl = cbAlloc - SECURITY_DESCRIPTOR_MIN_LENGTH * 2;
+        PACL const     pDacl  = (PACL)((uint8_t *)pSecDesc + SECURITY_DESCRIPTOR_MIN_LENGTH * 2);
+
+        if (   InitializeSecurityDescriptor(pSecDesc, SECURITY_DESCRIPTOR_REVISION)
+            && InitializeAcl(pDacl, cbDacl, ACL_REVISION))
+        {
+            if (rtLocalIpcBuildDacl(pDacl, fServer))
+            {
+                *ppDesc = pSecDesc;
+                return VINF_SUCCESS;
+            }
+            rc = VERR_GENERAL_FAILURE;
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        LocalFree(pSecDesc);
+    }
+    return rc;
+}
+
+
+/**
+ * Creates a named pipe instance.
+ *
+ * This is used by both RTLocalIpcServerCreate and RTLocalIpcServerListen.
+ *
+ * @return  IPRT status code.
+ * @param   phNmPipe        Where to store the named pipe handle on success.
+ *                          This will be set to INVALID_HANDLE_VALUE on failure.
+ * @param   pwszPipeName    The named pipe name, full, UTF-16 encoded.
+ * @param   fFirst          Set on the first call (from RTLocalIpcServerCreate),
+ *                          otherwise clear. Governs the
+ *                          FILE_FLAG_FIRST_PIPE_INSTANCE flag.
+ */
+static int rtLocalIpcServerWinCreatePipeInstance(PHANDLE phNmPipe, PCRTUTF16 pwszPipeName, bool fFirst)
+{
+    *phNmPipe = INVALID_HANDLE_VALUE;
+
+    /*
+     * Create a security descriptor blocking access to the pipe via network.
+     */
+    PSECURITY_DESCRIPTOR pSecDesc;
+    int rc = rtLocalIpcServerWinAllocSecurityDescriptor(&pSecDesc, fFirst /* Server? */);
+    if (RT_SUCCESS(rc))
+    {
+#if 0
+        { /* Just for checking the security descriptor out in the debugger (!sd <addr> doesn't work): */
+            DWORD dwRet = LookupSecurityDescriptorPartsW(NULL, NULL, NULL, NULL, NULL, NULL, pSecDesc);
+            __debugbreak(); RT_NOREF(dwRet);
+
+            PTRUSTEE_W          pOwner = NULL;
+            PTRUSTEE_W          pGroup = NULL;
+            ULONG               cAces  = 0;
+            PEXPLICIT_ACCESS_W  paAces = NULL;
+            ULONG               cAuditEntries = 0;
+            PEXPLICIT_ACCESS_W  paAuditEntries = NULL;
+            dwRet = LookupSecurityDescriptorPartsW(&pOwner, NULL, NULL, NULL, NULL, NULL, pSecDesc);
+            dwRet = LookupSecurityDescriptorPartsW(NULL, &pGroup, NULL, NULL, NULL, NULL, pSecDesc);
+            dwRet = LookupSecurityDescriptorPartsW(NULL, NULL, &cAces, &paAces, NULL, NULL, pSecDesc);
+            dwRet = LookupSecurityDescriptorPartsW(NULL, NULL, NULL, NULL, &cAuditEntries, &paAuditEntries, pSecDesc);
+            __debugbreak(); RT_NOREF(dwRet);
+        }
+#endif
+
+        /*
+         * Now, create the pipe.
+         */
+        SECURITY_ATTRIBUTES SecAttrs;
+        SecAttrs.nLength              = sizeof(SECURITY_ATTRIBUTES);
+        SecAttrs.lpSecurityDescriptor = pSecDesc;
+        SecAttrs.bInheritHandle       = FALSE;
+
+        DWORD fOpenMode = PIPE_ACCESS_DUPLEX
+                        | PIPE_WAIT
+                        | FILE_FLAG_OVERLAPPED;
+        if (   fFirst
+            && (   g_enmWinVer >= kRTWinOSType_XP
+                || (   g_enmWinVer == kRTWinOSType_2K
+                    && g_WinOsInfoEx.wServicePackMajor >= 2) ) )
+            fOpenMode |= FILE_FLAG_FIRST_PIPE_INSTANCE; /* Introduced with W2K SP2 */
+
+        HANDLE hNmPipe = CreateNamedPipeW(pwszPipeName,                  /* lpName */
+                                          fOpenMode,                     /* dwOpenMode */
+                                          PIPE_TYPE_BYTE,                /* dwPipeMode */
+                                          PIPE_UNLIMITED_INSTANCES,      /* nMaxInstances */
+                                          PAGE_SIZE,                     /* nOutBufferSize (advisory) */
+                                          PAGE_SIZE,                     /* nInBufferSize (ditto) */
+                                          30*1000,                       /* nDefaultTimeOut = 30 sec */
+                                          &SecAttrs);                    /* lpSecurityAttributes */
+        if (hNmPipe != INVALID_HANDLE_VALUE)
+        {
+#if 0 /* For checking access control stuff in windbg (doesn't work): */
+            PSECURITY_DESCRIPTOR pSecDesc2 = NULL;
+            PACL pDacl = NULL;
+            DWORD dwRet;
+            dwRet = GetSecurityInfo(hNmPipe, SE_FILE_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, &pDacl, NULL, &pSecDesc2);
+            PACL pSacl = NULL;
+            dwRet = GetSecurityInfo(hNmPipe, SE_FILE_OBJECT, SACL_SECURITY_INFORMATION, NULL, NULL, NULL, &pSacl, &pSecDesc2);
+            dwRet = GetSecurityInfo(hNmPipe, SE_FILE_OBJECT, DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION, NULL, NULL, &pDacl, &pSacl, &pSecDesc2);
+            PSID pSidOwner = NULL;
+            dwRet = GetSecurityInfo(hNmPipe, SE_FILE_OBJECT, OWNER_SECURITY_INFORMATION, &pSidOwner, NULL, NULL, NULL, &pSecDesc2);
+            PSID pSidGroup = NULL;
+            dwRet = GetSecurityInfo(hNmPipe, SE_FILE_OBJECT, OWNER_SECURITY_INFORMATION, NULL, &pSidGroup, NULL, NULL, &pSecDesc2);
+            __debugbreak();
+            RT_NOREF(dwRet);
+#endif
+            *phNmPipe = hNmPipe;
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        LocalFree(pSecDesc);
+    }
+    return rc;
+}
+
+
+/**
+ * Validates the user specified name.
+ *
+ * @returns IPRT status code.
+ * @param   pszName         The name to validate.
+ * @param   pcwcFullName    Where to return the UTF-16 length of the full name.
+ * @param   fNative         Whether it's a native name or a portable name.
+ */
+static int rtLocalIpcWinValidateName(const char *pszName, size_t *pcwcFullName, bool fNative)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertReturn(*pszName, VERR_INVALID_NAME);
+
+    if (!fNative)
+    {
+        size_t cwcName = RT_ELEMENTS(RTLOCALIPC_WIN_PREFIX) - 1;
+        for (;;)
+        {
+            char ch = *pszName++;
+            if (!ch)
+                break;
+            AssertReturn(!RT_C_IS_CNTRL(ch), VERR_INVALID_NAME);
+            AssertReturn((unsigned)ch < 0x80, VERR_INVALID_NAME);
+            AssertReturn(ch != '\\', VERR_INVALID_NAME);
+            AssertReturn(ch != '/', VERR_INVALID_NAME);
+            cwcName++;
+        }
+        *pcwcFullName = cwcName;
+    }
+    else
+    {
+        int rc = RTStrCalcUtf16LenEx(pszName, RTSTR_MAX, pcwcFullName);
+        AssertRCReturn(rc, rc);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Constructs the full pipe name as UTF-16.
+ *
+ * @returns IPRT status code.
+ * @param   pszName         The user supplied name.  ASSUMES reasonable length
+ *                          for now, so no long path prefixing needed.
+ * @param   pwszFullName    The output buffer.
+ * @param   cwcFullName     The output buffer size excluding the terminator.
+ * @param   fNative         Whether the user supplied name is a native or
+ *                          portable one.
+ */
+static int rtLocalIpcWinConstructName(const char *pszName, PRTUTF16 pwszFullName, size_t cwcFullName, bool fNative)
+{
+    if (!fNative)
+    {
+        static RTUTF16 const s_wszPrefix[] = RTLOCALIPC_WIN_PREFIX;
+        Assert(cwcFullName * sizeof(RTUTF16) > sizeof(s_wszPrefix));
+        memcpy(pwszFullName, s_wszPrefix, sizeof(s_wszPrefix));
+        cwcFullName  -= RT_ELEMENTS(s_wszPrefix) - 1;
+        pwszFullName += RT_ELEMENTS(s_wszPrefix) - 1;
+    }
+    return RTStrToUtf16Ex(pszName, RTSTR_MAX, &pwszFullName, cwcFullName + 1, NULL);
+}
+
+
+RTDECL(int) RTLocalIpcServerCreate(PRTLOCALIPCSERVER phServer, const char *pszName, uint32_t fFlags)
+{
+    /*
+     * Validate parameters.
+     */
+    AssertPtrReturn(phServer, VERR_INVALID_POINTER);
+    *phServer = NIL_RTLOCALIPCSERVER;
+    AssertReturn(!(fFlags & ~RTLOCALIPC_FLAGS_VALID_MASK), VERR_INVALID_FLAGS);
+    size_t cwcFullName;
+    int rc = rtLocalIpcWinValidateName(pszName, &cwcFullName, RT_BOOL(fFlags & RTLOCALIPC_FLAGS_NATIVE_NAME));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Allocate and initialize the instance data.
+         */
+        size_t cbThis = RT_UOFFSETOF_DYN(RTLOCALIPCSERVERINT, wszName[cwcFullName + 1]);
+        PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)RTMemAllocVar(cbThis);
+        AssertReturn(pThis, VERR_NO_MEMORY);
+
+        pThis->u32Magic   = RTLOCALIPCSERVER_MAGIC;
+        pThis->cRefs      = 1; /* the one we return */
+        pThis->fCancelled = false;
+
+        rc = rtLocalIpcWinConstructName(pszName, pThis->wszName, cwcFullName, RT_BOOL(fFlags & RTLOCALIPC_FLAGS_NATIVE_NAME));
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTCritSectInit(&pThis->CritSect);
+            if (RT_SUCCESS(rc))
+            {
+                pThis->hEvent = CreateEvent(NULL /*lpEventAttributes*/, TRUE /*bManualReset*/,
+                                            FALSE /*bInitialState*/, NULL /*lpName*/);
+                if (pThis->hEvent != NULL)
+                {
+                    RT_ZERO(pThis->OverlappedIO);
+                    pThis->OverlappedIO.Internal = STATUS_PENDING;
+                    pThis->OverlappedIO.hEvent   = pThis->hEvent;
+
+                    rc = rtLocalIpcServerWinCreatePipeInstance(&pThis->hNmPipe, pThis->wszName, true /* fFirst */);
+                    if (RT_SUCCESS(rc))
+                    {
+                        *phServer = pThis;
+                        return VINF_SUCCESS;
+                    }
+
+                    BOOL fRc = CloseHandle(pThis->hEvent);
+                    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+
+                int rc2 = RTCritSectDelete(&pThis->CritSect);
+                AssertRC(rc2);
+            }
+        }
+        RTMemFree(pThis);
+    }
+    return rc;
+}
+
+
+/**
+ * Retains a reference to the server instance.
+ *
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(void) rtLocalIpcServerRetain(PRTLOCALIPCSERVERINT pThis)
+{
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs); NOREF(cRefs);
+}
+
+
+/**
+ * Call when the reference count reaches 0.
+ *
+ * Caller owns the critsect.
+ *
+ * @returns VINF_OBJECT_DESTROYED
+ * @param   pThis       The instance to destroy.
+ */
+DECL_NO_INLINE(static, int) rtLocalIpcServerWinDestroy(PRTLOCALIPCSERVERINT pThis)
+{
+    Assert(pThis->u32Magic == ~RTLOCALIPCSERVER_MAGIC);
+    pThis->u32Magic = ~RTLOCALIPCSERVER_MAGIC;
+
+    BOOL fRc = CloseHandle(pThis->hNmPipe);
+    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    pThis->hNmPipe = INVALID_HANDLE_VALUE;
+
+    fRc = CloseHandle(pThis->hEvent);
+    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    pThis->hEvent = NULL;
+
+    RTCritSectLeave(&pThis->CritSect);
+    RTCritSectDelete(&pThis->CritSect);
+
+    RTMemFree(pThis);
+    return VINF_OBJECT_DESTROYED;
+}
+
+
+/**
+ * Server instance destructor.
+ *
+ * @returns VINF_OBJECT_DESTROYED
+ * @param   pThis               The server instance.
+ */
+DECL_NO_INLINE(static, int) rtLocalIpcServerDtor(PRTLOCALIPCSERVERINT pThis)
+{
+    RTCritSectEnter(&pThis->CritSect);
+    return rtLocalIpcServerWinDestroy(pThis);
+}
+
+
+/**
+ * Releases a reference to the server instance.
+ *
+ * @returns VINF_SUCCESS if only release, VINF_OBJECT_DESTROYED if destroyed.
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(int) rtLocalIpcServerRelease(PRTLOCALIPCSERVERINT pThis)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (!cRefs)
+        return rtLocalIpcServerDtor(pThis);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Releases a reference to the server instance and leaves the critsect.
+ *
+ * @returns VINF_SUCCESS if only release, VINF_OBJECT_DESTROYED if destroyed.
+ * @param   pThis               The server instance.
+ */
+DECLINLINE(int) rtLocalIpcServerReleaseAndUnlock(PRTLOCALIPCSERVERINT pThis)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (!cRefs)
+        return rtLocalIpcServerWinDestroy(pThis);
+    return RTCritSectLeave(&pThis->CritSect);
+}
+
+
+
+RTDECL(int) RTLocalIpcServerDestroy(RTLOCALIPCSERVER hServer)
+{
+    /*
+     * Validate input.
+     */
+    if (hServer == NIL_RTLOCALIPCSERVER)
+        return VINF_SUCCESS;
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Cancel any thread currently busy using the server,
+     * leaving the cleanup to it.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTLOCALIPCSERVER_MAGIC, RTLOCALIPCSERVER_MAGIC), VERR_WRONG_ORDER);
+
+    RTCritSectEnter(&pThis->CritSect);
+
+    /* Cancel everything. */
+    ASMAtomicUoWriteBool(&pThis->fCancelled, true);
+    if (pThis->cRefs > 1)
+    {
+        BOOL fRc = SetEvent(pThis->hEvent);
+        AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    }
+
+    return rtLocalIpcServerReleaseAndUnlock(pThis);
+}
+
+
+RTDECL(int) RTLocalIpcServerGrantGroupAccess(RTLOCALIPCSERVER hServer, RTGID gid)
+{
+    RT_NOREF_PV(hServer); RT_NOREF(gid);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTLocalIpcServerListen(RTLOCALIPCSERVER hServer, PRTLOCALIPCSESSION phClientSession)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(phClientSession, VERR_INVALID_POINTER);
+
+    /*
+     * Enter the critsect before inspecting the object further.
+     */
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, rc);
+
+    rtLocalIpcServerRetain(pThis);
+    if (!pThis->fCancelled)
+    {
+        ResetEvent(pThis->hEvent);
+
+        RTCritSectLeave(&pThis->CritSect);
+
+        /*
+         * Try connect a client. We need to use overlapped I/O here because
+         * of the cancellation done by RTLocalIpcServerCancel and RTLocalIpcServerDestroy.
+         */
+        SetLastError(NO_ERROR);
+        BOOL fRc = ConnectNamedPipe(pThis->hNmPipe, &pThis->OverlappedIO);
+        DWORD dwErr = fRc ? NO_ERROR : GetLastError();
+        if (    !fRc
+            &&  dwErr == ERROR_IO_PENDING)
+        {
+            WaitForSingleObject(pThis->hEvent, INFINITE);
+            DWORD dwIgnored;
+            fRc = GetOverlappedResult(pThis->hNmPipe, &pThis->OverlappedIO, &dwIgnored, FALSE /* bWait*/);
+            dwErr = fRc ? NO_ERROR : GetLastError();
+        }
+
+        RTCritSectEnter(&pThis->CritSect);
+        if (   !pThis->fCancelled /* Event signalled but not cancelled? */
+            && pThis->u32Magic == RTLOCALIPCSERVER_MAGIC)
+        {
+            /*
+             * Still alive, some error or an actual client.
+             *
+             * If it's the latter we'll have to create a new pipe instance that
+             * replaces the current one for the server. The current pipe instance
+             * will be assigned to the client session.
+             */
+            if (   fRc
+                || dwErr == ERROR_PIPE_CONNECTED)
+            {
+                HANDLE hNmPipe;
+                rc = rtLocalIpcServerWinCreatePipeInstance(&hNmPipe, pThis->wszName, false /* fFirst */);
+                if (RT_SUCCESS(rc))
+                {
+                    HANDLE hNmPipeSession = pThis->hNmPipe; /* consumed */
+                    pThis->hNmPipe = hNmPipe;
+                    rc = rtLocalIpcWinCreateSession(phClientSession, hNmPipeSession);
+                }
+                else
+                {
+                    /*
+                     * We failed to create a new instance for the server, disconnect
+                     * the client and fail. Don't try service the client here.
+                     */
+                    fRc = DisconnectNamedPipe(pThis->hNmPipe);
+                    AssertMsg(fRc, ("%d\n", GetLastError()));
+                }
+            }
+            else
+                rc = RTErrConvertFromWin32(dwErr);
+        }
+        else
+        {
+            /*
+             * Cancelled.
+             *
+             * Cancel the overlapped io if it didn't complete (must be done
+             * in the this thread) or disconnect the client.
+             */
+            Assert(pThis->fCancelled);
+            if (    fRc
+                ||  dwErr == ERROR_PIPE_CONNECTED)
+                fRc = DisconnectNamedPipe(pThis->hNmPipe);
+            else if (dwErr == ERROR_IO_PENDING)
+            {
+                IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+                NTSTATUS rcNt = NtCancelIoFile(pThis->hNmPipe, &Ios);
+                fRc = NT_SUCCESS(rcNt);
+            }
+            else
+                fRc = TRUE;
+            AssertMsg(fRc, ("%d\n", GetLastError()));
+            rc = VERR_CANCELLED;
+        }
+    }
+    else
+    {
+        /*pThis->fCancelled = false; - Terrible interface idea. Add API to clear fCancelled if ever required. */
+        rc = VERR_CANCELLED;
+    }
+    rtLocalIpcServerReleaseAndUnlock(pThis);
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcServerCancel(RTLOCALIPCSERVER hServer)
+{
+    /*
+     * Validate input.
+     */
+    PRTLOCALIPCSERVERINT pThis = (PRTLOCALIPCSERVERINT)hServer;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSERVER_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Enter the critical section, then set the cancellation flag
+     * and signal the event (to wake up anyone in/at WaitForSingleObject).
+     */
+    rtLocalIpcServerRetain(pThis);
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        ASMAtomicUoWriteBool(&pThis->fCancelled, true);
+
+        BOOL fRc = SetEvent(pThis->hEvent);
+        if (fRc)
+            rc = VINF_SUCCESS;
+        else
+        {
+            DWORD dwErr = GetLastError();
+            AssertMsgFailed(("dwErr=%u\n", dwErr));
+            rc = RTErrConvertFromWin32(dwErr);
+        }
+
+        rtLocalIpcServerReleaseAndUnlock(pThis);
+    }
+    else
+        rtLocalIpcServerRelease(pThis);
+    return rc;
+}
+
+
+/**
+ * Create a session instance for a new server client or a client connect.
+ *
+ * @returns IPRT status code.
+ *
+ * @param   ppSession       Where to store the session handle on success.
+ * @param   hNmPipeSession  The named pipe handle if server calling,
+ *                          INVALID_HANDLE_VALUE if client connect.  This will
+ *                          be consumed by this session, meaning on failure to
+ *                          create the session it will be closed.
+ */
+static int rtLocalIpcWinCreateSession(PRTLOCALIPCSESSIONINT *ppSession, HANDLE hNmPipeSession)
+{
+    AssertPtr(ppSession);
+
+    /*
+     * Allocate and initialize the session instance data.
+     */
+    int rc;
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        pThis->u32Magic         = RTLOCALIPCSESSION_MAGIC;
+        pThis->cRefs            = 1; /* our ref */
+        pThis->fCancelled       = false;
+        pThis->fZeroByteRead    = false;
+        pThis->fServerSide      = hNmPipeSession != INVALID_HANDLE_VALUE;
+        pThis->hNmPipe          = hNmPipeSession;
+#if 0 /* Non-blocking writes are not yet supported. */
+        pThis->pbBounceBuf      = NULL;
+        pThis->cbBounceBufAlloc = 0;
+        pThis->cbBounceBufUsed  = 0;
+#endif
+        rc = RTCritSectInit(&pThis->CritSect);
+        if (RT_SUCCESS(rc))
+        {
+            pThis->Read.hEvent = CreateEvent(NULL /*lpEventAttributes*/, TRUE /*bManualReset*/,
+                                             FALSE /*bInitialState*/, NULL /*lpName*/);
+            if (pThis->Read.hEvent != NULL)
+            {
+                pThis->Read.OverlappedIO.Internal = STATUS_PENDING;
+                pThis->Read.OverlappedIO.hEvent   = pThis->Read.hEvent;
+                pThis->Read.hActiveThread         = NIL_RTTHREAD;
+
+                pThis->Write.hEvent = CreateEvent(NULL /*lpEventAttributes*/, TRUE /*bManualReset*/,
+                                                  FALSE /*bInitialState*/, NULL /*lpName*/);
+                if (pThis->Write.hEvent != NULL)
+                {
+                    pThis->Write.OverlappedIO.Internal = STATUS_PENDING;
+                    pThis->Write.OverlappedIO.hEvent   = pThis->Write.hEvent;
+                    pThis->Write.hActiveThread         = NIL_RTTHREAD;
+
+                    *ppSession = pThis;
+                    return VINF_SUCCESS;
+                }
+
+                CloseHandle(pThis->Read.hEvent);
+            }
+
+            /* bail out */
+            rc = RTErrConvertFromWin32(GetLastError());
+            RTCritSectDelete(&pThis->CritSect);
+        }
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    if (hNmPipeSession != INVALID_HANDLE_VALUE)
+    {
+        BOOL fRc = CloseHandle(hNmPipeSession);
+        AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionConnect(PRTLOCALIPCSESSION phSession, const char *pszName, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(phSession, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTLOCALIPC_C_FLAGS_VALID_MASK), VERR_INVALID_FLAGS);
+
+    size_t cwcFullName;
+    int rc = rtLocalIpcWinValidateName(pszName, &cwcFullName, RT_BOOL(fFlags & RTLOCALIPC_C_FLAGS_NATIVE_NAME));
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Create a session (shared with server client session creation).
+         */
+        PRTLOCALIPCSESSIONINT pThis;
+        rc = rtLocalIpcWinCreateSession(&pThis, INVALID_HANDLE_VALUE);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Try open the pipe.
+             */
+            PSECURITY_DESCRIPTOR pSecDesc;
+            rc = rtLocalIpcServerWinAllocSecurityDescriptor(&pSecDesc, false /*fServer*/);
+            if (RT_SUCCESS(rc))
+            {
+                PRTUTF16 pwszFullName = RTUtf16Alloc((cwcFullName + 1) * sizeof(RTUTF16));
+                if (pwszFullName)
+                    rc = rtLocalIpcWinConstructName(pszName, pwszFullName, cwcFullName,
+                                                    RT_BOOL(fFlags & RTLOCALIPC_C_FLAGS_NATIVE_NAME));
+                else
+                    rc = VERR_NO_UTF16_MEMORY;
+                if (RT_SUCCESS(rc))
+                {
+                    SECURITY_ATTRIBUTES SecAttrs;
+                    SecAttrs.nLength              = sizeof(SECURITY_ATTRIBUTES);
+                    SecAttrs.lpSecurityDescriptor = pSecDesc;
+                    SecAttrs.bInheritHandle       = FALSE;
+
+                    /* The SECURITY_XXX flags are needed in order to prevent the server from impersonating with
+                       this thread's security context (supported at least back to NT 3.51). See @bugref{9773}. */
+                    HANDLE hPipe = CreateFileW(pwszFullName,
+                                               GENERIC_READ | GENERIC_WRITE,
+                                               0 /*no sharing*/,
+                                               &SecAttrs,
+                                               OPEN_EXISTING,
+                                               FILE_FLAG_OVERLAPPED | SECURITY_SQOS_PRESENT | SECURITY_ANONYMOUS,
+                                               NULL /*no template handle*/);
+                    if (hPipe != INVALID_HANDLE_VALUE)
+                    {
+                        pThis->hNmPipe = hPipe;
+
+                        LocalFree(pSecDesc);
+                        RTUtf16Free(pwszFullName);
+
+                        /*
+                         * We're done!
+                         */
+                        *phSession = pThis;
+                        return VINF_SUCCESS;
+                    }
+
+                    rc = RTErrConvertFromWin32(GetLastError());
+                }
+
+                RTUtf16Free(pwszFullName);
+                LocalFree(pSecDesc);
+            }
+
+            /* destroy the session handle. */
+            CloseHandle(pThis->Read.hEvent);
+            CloseHandle(pThis->Write.hEvent);
+            RTCritSectDelete(&pThis->CritSect);
+
+            RTMemFree(pThis);
+        }
+    }
+    return rc;
+}
+
+
+/**
+ * Cancells all pending I/O operations, forcing the methods to return with
+ * VERR_CANCELLED (unless they've got actual data to return).
+ *
+ * Used by RTLocalIpcSessionCancel and RTLocalIpcSessionClose.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The client session instance.
+ */
+static int rtLocalIpcWinCancel(PRTLOCALIPCSESSIONINT pThis)
+{
+    ASMAtomicUoWriteBool(&pThis->fCancelled, true);
+
+    /*
+     * Call NtCancelIoFile since this call cancels both read and write
+     * oriented operations.
+     */
+    if (   pThis->fZeroByteRead
+        || pThis->Read.hActiveThread != NIL_RTTHREAD
+        || pThis->Write.hActiveThread != NIL_RTTHREAD)
+    {
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NtCancelIoFile(pThis->hNmPipe, &Ios);
+    }
+
+    /*
+     * Set both event semaphores.
+     */
+    BOOL fRc = SetEvent(pThis->Read.hEvent);
+    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    fRc = SetEvent(pThis->Write.hEvent);
+    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Retains a reference to the session instance.
+ *
+ * @param   pThis               The client session instance.
+ */
+DECLINLINE(void) rtLocalIpcSessionRetain(PRTLOCALIPCSESSIONINT pThis)
+{
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs); NOREF(cRefs);
+}
+
+
+RTDECL(uint32_t) RTLocalIpcSessionRetain(RTLOCALIPCSESSION hSession)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2 && cRefs);
+    return cRefs;
+}
+
+
+/**
+ * Call when the reference count reaches 0.
+ *
+ * Caller owns the critsect.
+ *
+ * @returns VINF_OBJECT_DESTROYED
+ * @param   pThis       The instance to destroy.
+ */
+DECL_NO_INLINE(static, int) rtLocalIpcSessionWinDestroy(PRTLOCALIPCSESSIONINT pThis)
+{
+    BOOL fRc = CloseHandle(pThis->hNmPipe);
+    AssertMsg(fRc, ("%d\n", GetLastError())); NOREF(fRc);
+    pThis->hNmPipe = INVALID_HANDLE_VALUE;
+
+    fRc = CloseHandle(pThis->Write.hEvent);
+    AssertMsg(fRc, ("%d\n", GetLastError()));
+    pThis->Write.hEvent = NULL;
+
+    fRc = CloseHandle(pThis->Read.hEvent);
+    AssertMsg(fRc, ("%d\n", GetLastError()));
+    pThis->Read.hEvent = NULL;
+
+    int rc2 = RTCritSectLeave(&pThis->CritSect); AssertRC(rc2);
+    RTCritSectDelete(&pThis->CritSect);
+
+    RTMemFree(pThis);
+    return VINF_OBJECT_DESTROYED;
+}
+
+
+/**
+ * Releases a reference to the session instance and unlock it.
+ *
+ * @returns VINF_SUCCESS or VINF_OBJECT_DESTROYED as appropriate.
+ * @param   pThis               The session instance.
+ */
+DECLINLINE(int) rtLocalIpcSessionReleaseAndUnlock(PRTLOCALIPCSESSIONINT pThis)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (!cRefs)
+        return rtLocalIpcSessionWinDestroy(pThis);
+
+    int rc2 = RTCritSectLeave(&pThis->CritSect); AssertRC(rc2);
+    Log(("rtLocalIpcSessionReleaseAndUnlock: %u refs left\n", cRefs));
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTLocalIpcSessionRelease(RTLOCALIPCSESSION hSession)
+{
+    if (hSession == NIL_RTLOCALIPCSESSION)
+        return 0;
+
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    Assert(cRefs < UINT32_MAX / 2);
+    if (cRefs)
+        Log(("RTLocalIpcSessionRelease: %u refs left\n", cRefs));
+    else
+    {
+        RTCritSectEnter(&pThis->CritSect);
+        rtLocalIpcSessionWinDestroy(pThis);
+    }
+    return cRefs;
+}
+
+
+RTDECL(int) RTLocalIpcSessionClose(RTLOCALIPCSESSION hSession)
+{
+    /*
+     * Validate input.
+     */
+    if (hSession == NIL_RTLOCALIPCSESSION)
+        return VINF_SUCCESS;
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the instance, cancel all outstanding I/O and drop our reference.
+     */
+    RTCritSectEnter(&pThis->CritSect);
+    rtLocalIpcWinCancel(pThis);
+    return rtLocalIpcSessionReleaseAndUnlock(pThis);
+}
+
+
+/**
+ * Handles WaitForSingleObject return value when waiting for a zero byte read.
+ *
+ * The zero byte read is started by the RTLocalIpcSessionWaitForData method and
+ * left pending when the function times out.  This saves us the problem of
+ * NtCancelIoFile messing with all active I/O operations and the trouble of
+ * restarting the zero byte read the next time the method is called.  However
+ * should RTLocalIpcSessionRead be called after a failed
+ * RTLocalIpcSessionWaitForData call, the zero byte read will still be pending
+ * and it must wait for it to complete before the OVERLAPPEDIO structure can be
+ * reused.
+ *
+ * Thus, both functions will do WaitForSingleObject and share this routine to
+ * handle the outcome.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The session instance.
+ * @param   rcWait              The WaitForSingleObject return code.
+ */
+static int rtLocalIpcWinGetZeroReadResult(PRTLOCALIPCSESSIONINT pThis, DWORD rcWait)
+{
+    int rc;
+    DWORD cbRead = 42;
+    if (rcWait == WAIT_OBJECT_0)
+    {
+        if (GetOverlappedResult(pThis->hNmPipe, &pThis->Read.OverlappedIO, &cbRead, !pThis->fCancelled /*fWait*/))
+        {
+            Assert(cbRead == 0);
+            rc = VINF_SUCCESS;
+            pThis->fZeroByteRead = false;
+        }
+        else if (pThis->fCancelled)
+            rc = VERR_CANCELLED;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        /* We try get the result here too, just in case we're lucky, but no waiting. */
+        DWORD dwErr = GetLastError();
+        if (GetOverlappedResult(pThis->hNmPipe, &pThis->Read.OverlappedIO, &cbRead, FALSE /*fWait*/))
+        {
+            Assert(cbRead == 0);
+            rc = VINF_SUCCESS;
+            pThis->fZeroByteRead = false;
+        }
+        else if (rcWait == WAIT_TIMEOUT)
+            rc = VERR_TIMEOUT;
+        else if (rcWait == WAIT_ABANDONED)
+            rc = VERR_INVALID_HANDLE;
+        else
+            rc = RTErrConvertFromWin32(dwErr);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionRead(RTLOCALIPCSESSION hSession, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    /* pcbRead is optional. */
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rtLocalIpcSessionRetain(pThis);
+        if (pThis->Read.hActiveThread == NIL_RTTHREAD)
+        {
+            pThis->Read.hActiveThread = RTThreadSelf();
+
+            size_t cbTotalRead = 0;
+            while (cbToRead > 0)
+            {
+                DWORD cbRead = 0;
+                if (!pThis->fCancelled)
+                {
+                    /*
+                     * Wait for pending zero byte read, if necessary.
+                     * Note! It cannot easily be cancelled due to concurrent current writes.
+                     */
+                    if (!pThis->fZeroByteRead)
+                    { /* likely */ }
+                    else
+                    {
+                        RTCritSectLeave(&pThis->CritSect);
+                        DWORD rcWait = WaitForSingleObject(pThis->Read.OverlappedIO.hEvent, RT_MS_1MIN);
+                        RTCritSectEnter(&pThis->CritSect);
+
+                        rc = rtLocalIpcWinGetZeroReadResult(pThis, rcWait);
+                        if (RT_SUCCESS(rc) || rc == VERR_TIMEOUT)
+                            continue;
+                        break;
+                    }
+
+                    /*
+                     * Kick of a an overlapped read.  It should return immediately if
+                     * there is bytes in the buffer.  If not, we'll cancel it and see
+                     * what we get back.
+                     */
+                    rc = ResetEvent(pThis->Read.OverlappedIO.hEvent); Assert(rc == TRUE);
+                    RTCritSectLeave(&pThis->CritSect);
+
+                    if (ReadFile(pThis->hNmPipe, pvBuf,
+                                 cbToRead <= ~(DWORD)0 ? (DWORD)cbToRead : ~(DWORD)0,
+                                 &cbRead, &pThis->Read.OverlappedIO))
+                    {
+                        RTCritSectEnter(&pThis->CritSect);
+                        rc = VINF_SUCCESS;
+                    }
+                    else if (GetLastError() == ERROR_IO_PENDING)
+                    {
+                        WaitForSingleObject(pThis->Read.OverlappedIO.hEvent, INFINITE);
+
+                        RTCritSectEnter(&pThis->CritSect);
+                        if (GetOverlappedResult(pThis->hNmPipe, &pThis->Read.OverlappedIO, &cbRead, TRUE /*fWait*/))
+                            rc = VINF_SUCCESS;
+                        else
+                        {
+                            if (pThis->fCancelled)
+                                rc = VERR_CANCELLED;
+                            else
+                                rc = RTErrConvertFromWin32(GetLastError());
+                            break;
+                        }
+                    }
+                    else
+                    {
+                        rc = RTErrConvertFromWin32(GetLastError());
+                        AssertMsgFailedBreak(("%Rrc\n", rc));
+                    }
+                }
+                else
+                {
+                    rc = VERR_CANCELLED;
+                    break;
+                }
+
+                /* Advance. */
+                cbToRead    -= cbRead;
+                cbTotalRead += cbRead;
+                pvBuf     = (uint8_t *)pvBuf + cbRead;
+            }
+
+            if (pcbRead)
+            {
+                *pcbRead = cbTotalRead;
+                if (   RT_FAILURE(rc)
+                    && cbTotalRead
+                    && rc != VERR_INVALID_POINTER)
+                    rc = VINF_SUCCESS;
+            }
+
+            pThis->Read.hActiveThread = NIL_RTTHREAD;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        rtLocalIpcSessionReleaseAndUnlock(pThis);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionReadNB(RTLOCALIPCSESSION hSession, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertPtrReturn(pcbRead, VERR_INVALID_POINTER);
+    *pcbRead = 0;
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rtLocalIpcSessionRetain(pThis);
+        if (pThis->Read.hActiveThread == NIL_RTTHREAD)
+        {
+            pThis->Read.hActiveThread = RTThreadSelf();
+
+            for (;;)
+            {
+                DWORD cbRead = 0;
+                if (!pThis->fCancelled)
+                {
+                    /*
+                     * Wait for pending zero byte read, if necessary.
+                     * Note! It cannot easily be cancelled due to concurrent current writes.
+                     */
+                    if (!pThis->fZeroByteRead)
+                    { /* likely */ }
+                    else
+                    {
+                        RTCritSectLeave(&pThis->CritSect);
+                        DWORD rcWait = WaitForSingleObject(pThis->Read.OverlappedIO.hEvent, 0);
+                        RTCritSectEnter(&pThis->CritSect);
+
+                        rc = rtLocalIpcWinGetZeroReadResult(pThis, rcWait);
+                        if (RT_SUCCESS(rc))
+                            continue;
+
+                        if (rc == VERR_TIMEOUT)
+                            rc = VINF_TRY_AGAIN;
+                        break;
+                    }
+
+                    /*
+                     * Figure out how much we can read (cannot try and cancel here
+                     * like in the anonymous pipe code).
+                     */
+                    DWORD cbAvailable;
+                    if (PeekNamedPipe(pThis->hNmPipe, NULL, 0, NULL, &cbAvailable, NULL))
+                    {
+                        if (cbAvailable == 0 || cbToRead == 0)
+                        {
+                            *pcbRead = 0;
+                            rc = VINF_TRY_AGAIN;
+                            break;
+                        }
+                    }
+                    else
+                    {
+                        rc = RTErrConvertFromWin32(GetLastError());
+                        break;
+                    }
+                    if (cbAvailable > cbToRead)
+                        cbAvailable = (DWORD)cbToRead;
+
+                    /*
+                     * Kick of a an overlapped read.  It should return immediately, so we
+                     * don't really need to leave the critsect here.
+                     */
+                    rc = ResetEvent(pThis->Read.OverlappedIO.hEvent); Assert(rc == TRUE);
+                    if (ReadFile(pThis->hNmPipe, pvBuf, cbAvailable, &cbRead, &pThis->Read.OverlappedIO))
+                    {
+                        *pcbRead = cbRead;
+                        rc = VINF_SUCCESS;
+                    }
+                    else if (GetLastError() == ERROR_IO_PENDING)
+                    {
+                        DWORD rcWait = WaitForSingleObject(pThis->Read.OverlappedIO.hEvent, 0);
+                        if (rcWait == WAIT_TIMEOUT)
+                        {
+                            RTCritSectLeave(&pThis->CritSect);
+                            rcWait = WaitForSingleObject(pThis->Read.OverlappedIO.hEvent, INFINITE);
+                            RTCritSectEnter(&pThis->CritSect);
+                        }
+                        if (GetOverlappedResult(pThis->hNmPipe, &pThis->Read.OverlappedIO, &cbRead, TRUE /*fWait*/))
+                        {
+                            *pcbRead = cbRead;
+                            rc = VINF_SUCCESS;
+                        }
+                        else
+                        {
+                            if (pThis->fCancelled)
+                                rc = VERR_CANCELLED;
+                            else
+                                rc = RTErrConvertFromWin32(GetLastError());
+                        }
+                    }
+                    else
+                    {
+                        rc = RTErrConvertFromWin32(GetLastError());
+                        AssertMsgFailedBreak(("%Rrc\n", rc));
+                    }
+                }
+                else
+                    rc = VERR_CANCELLED;
+                break;
+            }
+
+            pThis->Read.hActiveThread = NIL_RTTHREAD;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        rtLocalIpcSessionReleaseAndUnlock(pThis);
+    }
+
+    return rc;
+}
+
+
+#if 0 /* Non-blocking writes are not yet supported. */
+/**
+ * Common worker for handling I/O completion.
+ *
+ * This is used by RTLocalIpcSessionClose and RTLocalIpcSessionWrite.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ */
+static int rtLocalIpcSessionWriteCheckCompletion(PRTLOCALIPCSESSIONINT pThis)
+{
+    int rc;
+    DWORD rcWait = WaitForSingleObject(pThis->OverlappedIO.hEvent, 0);
+    if (rcWait == WAIT_OBJECT_0)
+    {
+        DWORD cbWritten = 0;
+        if (GetOverlappedResult(pThis->hNmPipe, &pThis->OverlappedIO, &cbWritten, TRUE))
+        {
+            for (;;)
+            {
+                if (cbWritten >= pThis->cbBounceBufUsed)
+                {
+                    pThis->fIOPending = false;
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+
+                /* resubmit the remainder of the buffer - can this actually happen? */
+                memmove(&pThis->pbBounceBuf[0], &pThis->pbBounceBuf[cbWritten], pThis->cbBounceBufUsed - cbWritten);
+                rc = ResetEvent(pThis->OverlappedIO.hEvent); Assert(rc == TRUE);
+                if (!WriteFile(pThis->hNmPipe, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                               &cbWritten, &pThis->OverlappedIO))
+                {
+                    DWORD dwErr = GetLastError();
+                    if (dwErr == ERROR_IO_PENDING)
+                        rc = VINF_TRY_AGAIN;
+                    else
+                    {
+                        pThis->fIOPending = false;
+                        if (dwErr == ERROR_NO_DATA)
+                            rc = VERR_BROKEN_PIPE;
+                        else
+                            rc = RTErrConvertFromWin32(dwErr);
+                    }
+                    break;
+                }
+                Assert(cbWritten > 0);
+            }
+        }
+        else
+        {
+            pThis->fIOPending = false;
+            rc = RTErrConvertFromWin32(GetLastError());
+        }
+    }
+    else if (rcWait == WAIT_TIMEOUT)
+        rc = VINF_TRY_AGAIN;
+    else
+    {
+        pThis->fIOPending = false;
+        if (rcWait == WAIT_ABANDONED)
+            rc = VERR_INVALID_HANDLE;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    return rc;
+}
+#endif
+
+
+RTDECL(int) RTLocalIpcSessionWrite(RTLOCALIPCSESSION hSession, const void *pvBuf, size_t cbToWrite)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite, VERR_INVALID_PARAMETER);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rtLocalIpcSessionRetain(pThis);
+        if (pThis->Write.hActiveThread == NIL_RTTHREAD)
+        {
+            pThis->Write.hActiveThread = RTThreadSelf();
+
+            /*
+             * Try write everything. No bounce buffering necessary.
+             */
+            size_t cbTotalWritten = 0;
+            while (cbToWrite > 0)
+            {
+                DWORD cbWritten = 0;
+                if (!pThis->fCancelled)
+                {
+                    BOOL fRc = ResetEvent(pThis->Write.OverlappedIO.hEvent); Assert(fRc == TRUE);
+                    RTCritSectLeave(&pThis->CritSect);
+
+                    DWORD const cbToWriteInThisIteration = cbToWrite <= ~(DWORD)0 ? (DWORD)cbToWrite : ~(DWORD)0;
+                    fRc = WriteFile(pThis->hNmPipe, pvBuf, cbToWriteInThisIteration, &cbWritten, &pThis->Write.OverlappedIO);
+                    if (fRc)
+                        rc = VINF_SUCCESS;
+                    else
+                    {
+                        DWORD dwErr = GetLastError();
+                        if (dwErr == ERROR_IO_PENDING)
+                        {
+                            DWORD rcWait = WaitForSingleObject(pThis->Write.OverlappedIO.hEvent, INFINITE);
+                            if (rcWait == WAIT_OBJECT_0)
+                            {
+                                if (GetOverlappedResult(pThis->hNmPipe, &pThis->Write.OverlappedIO, &cbWritten, TRUE /*fWait*/))
+                                    rc = VINF_SUCCESS;
+                                else
+                                    rc = RTErrConvertFromWin32(GetLastError());
+                            }
+                            else if (rcWait == WAIT_TIMEOUT)
+                                rc = VERR_TIMEOUT;
+                            else if (rcWait == WAIT_ABANDONED)
+                                rc = VERR_INVALID_HANDLE;
+                            else
+                                rc = RTErrConvertFromWin32(GetLastError());
+                        }
+                        else if (dwErr == ERROR_NO_DATA)
+                            rc = VERR_BROKEN_PIPE;
+                        else
+                            rc = RTErrConvertFromWin32(dwErr);
+                    }
+
+                    if (cbWritten > cbToWriteInThisIteration) /* paranoia^3 */
+                        cbWritten = cbToWriteInThisIteration;
+
+                    RTCritSectEnter(&pThis->CritSect);
+                    if (RT_FAILURE(rc))
+                        break;
+                }
+                else
+                {
+                    rc = VERR_CANCELLED;
+                    break;
+                }
+
+                /* Advance. */
+                pvBuf           = (char const *)pvBuf + cbWritten;
+                cbTotalWritten += cbWritten;
+                cbToWrite      -= cbWritten;
+            }
+
+            pThis->Write.hActiveThread = NIL_RTTHREAD;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        rtLocalIpcSessionReleaseAndUnlock(pThis);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionFlush(RTLOCALIPCSESSION hSession)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        if (pThis->Write.hActiveThread == NIL_RTTHREAD)
+        {
+            /* No flushing on Windows needed since RTLocalIpcSessionWrite will block until
+             * all data was written (or an error occurred). */
+            /** @todo r=bird: above comment is misinformed.
+             *        Implement this as soon as we want an explicit asynchronous version of
+             *        RTLocalIpcSessionWrite on Windows. */
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionWaitForData(RTLOCALIPCSESSION hSession, uint32_t cMillies)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    uint64_t const msStart = RTTimeMilliTS();
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rtLocalIpcSessionRetain(pThis);
+        if (pThis->Read.hActiveThread == NIL_RTTHREAD)
+        {
+            pThis->Read.hActiveThread = RTThreadSelf();
+
+            /*
+             * Wait loop.
+             */
+            for (unsigned iLoop = 0;; iLoop++)
+            {
+                /*
+                 * Check for cancellation before we continue.
+                 */
+                if (!pThis->fCancelled)
+                { /* likely */ }
+                else
+                {
+                    rc = VERR_CANCELLED;
+                    break;
+                }
+
+                /*
+                 * Prep something we can wait on.
+                 */
+                HANDLE hWait = INVALID_HANDLE_VALUE;
+                if (pThis->fZeroByteRead)
+                    hWait = pThis->Read.OverlappedIO.hEvent;
+                else
+                {
+                    /* Peek at the pipe buffer and see how many bytes it contains. */
+                    DWORD cbAvailable;
+                    if (   PeekNamedPipe(pThis->hNmPipe, NULL, 0, NULL, &cbAvailable, NULL)
+                        && cbAvailable)
+                    {
+                        rc = VINF_SUCCESS;
+                        break;
+                    }
+
+                    /* Start a zero byte read operation that we can wait on. */
+                    if (cMillies == 0)
+                    {
+                        rc = VERR_TIMEOUT;
+                        break;
+                    }
+                    BOOL fRc = ResetEvent(pThis->Read.OverlappedIO.hEvent); Assert(fRc == TRUE); NOREF(fRc);
+                    DWORD cbRead = 0;
+                    if (ReadFile(pThis->hNmPipe, pThis->abBuf, 0 /*cbToRead*/, &cbRead, &pThis->Read.OverlappedIO))
+                    {
+                        rc = VINF_SUCCESS;
+                        if (iLoop > 10)
+                            RTThreadYield();
+                    }
+                    else if (GetLastError() == ERROR_IO_PENDING)
+                    {
+                        pThis->fZeroByteRead = true;
+                        hWait = pThis->Read.OverlappedIO.hEvent;
+                    }
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                    if (RT_FAILURE(rc))
+                        break;
+                }
+
+                /*
+                 * Check for timeout.
+                 */
+                DWORD cMsMaxWait = INFINITE; /* (MSC maybe used uninitialized) */
+                if (cMillies == RT_INDEFINITE_WAIT)
+                    cMsMaxWait = INFINITE;
+                else if (   hWait != INVALID_HANDLE_VALUE
+                         || iLoop > 10)
+                {
+                    uint64_t cMsElapsed = RTTimeMilliTS() - msStart;
+                    if (cMsElapsed <= cMillies)
+                        cMsMaxWait = cMillies - (uint32_t)cMsElapsed;
+                    else if (iLoop == 0)
+                        cMsMaxWait = cMillies ? 1 : 0;
+                    else
+                    {
+                        rc = VERR_TIMEOUT;
+                        break;
+                    }
+                }
+
+                /*
+                 * Wait and collect the result.
+                 */
+                if (hWait != INVALID_HANDLE_VALUE)
+                {
+                    RTCritSectLeave(&pThis->CritSect);
+
+                    DWORD rcWait = WaitForSingleObject(hWait, cMsMaxWait);
+
+                    int rc2 = RTCritSectEnter(&pThis->CritSect);
+                    AssertRC(rc2);
+
+                    rc = rtLocalIpcWinGetZeroReadResult(pThis, rcWait);
+                    break;
+                }
+            }
+
+            pThis->Read.hActiveThread = NIL_RTTHREAD;
+        }
+
+        rtLocalIpcSessionReleaseAndUnlock(pThis);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionCancel(RTLOCALIPCSESSION hSession)
+{
+    PRTLOCALIPCSESSIONINT pThis = (PRTLOCALIPCSESSIONINT)hSession;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTLOCALIPCSESSION_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Enter the critical section, then set the cancellation flag
+     * and signal the event (to wake up anyone in/at WaitForSingleObject).
+     */
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        rtLocalIpcSessionRetain(pThis);
+        rc = rtLocalIpcWinCancel(pThis);
+        rtLocalIpcSessionReleaseAndUnlock(pThis);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTLocalIpcSessionQueryProcess(RTLOCALIPCSESSION hSession, PRTPROCESS pProcess)
+{
+    RT_NOREF_PV(hSession); RT_NOREF_PV(pProcess);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTLocalIpcSessionQueryUserId(RTLOCALIPCSESSION hSession, PRTUID pUid)
+{
+    RT_NOREF_PV(hSession); RT_NOREF_PV(pUid);
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTLocalIpcSessionQueryGroupId(RTLOCALIPCSESSION hSession, PRTGID pGid)
+{
+    RT_NOREF_PV(hSession); RT_NOREF_PV(pGid);
+    return VERR_NOT_SUPPORTED;
+}
+
diff --git a/src/VBox/Runtime/r3/win/mp-win.cpp b/src/VBox/Runtime/r3/win/mp-win.cpp
new file mode 100644
index 00000000..b76ab254
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/mp-win.cpp
@@ -0,0 +1,822 @@
+/* $Id: mp-win.cpp $ */
+/** @file
+ * IPRT - Multiprocessor, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYSTEM
+#include <iprt/win/windows.h>
+
+#include <iprt/mp.h>
+#include "internal/iprt.h"
+
+#include <iprt/alloca.h>
+#include <iprt/assert.h>
+#include <iprt/cpuset.h>
+#include <iprt/ldr.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/param.h>
+#if defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
+# include <iprt/asm-amd64-x86.h>
+#endif
+#if defined(VBOX) && !defined(IN_GUEST) && !defined(IN_RT_STATIC)
+# include <VBox/sup.h>
+# define IPRT_WITH_GIP_MP_INFO
+#else
+# undef  IPRT_WITH_GIP_MP_INFO
+#endif
+
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** @def RTMPWIN_UPDATE_GIP_GLOBALS
+ * Does lazy (re-)initialization using information provieded by GIP. */
+#ifdef IPRT_WITH_GIP_MP_INFO
+# define RTMPWIN_UPDATE_GIP_GLOBALS() \
+    do { RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP(); } while (0)
+#else
+# define RTMPWIN_UPDATE_GIP_GLOBALS() do { } while (0)
+#endif
+
+/** @def RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP
+ * Does lazy (re-)initialization using information provieded by GIP and
+ * declare and initalize a pGip local variable. */
+#ifdef IPRT_WITH_GIP_MP_INFO
+#define RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP() \
+    PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage; \
+    if (pGip) \
+    { \
+        if (   pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC \
+            && RTOnce(&g_MpInitOnceGip, rtMpWinInitOnceGip, NULL) == VINF_SUCCESS) \
+        { \
+            if (g_cRtMpWinActiveCpus >= pGip->cOnlineCpus) \
+            { /* likely */ } \
+            else \
+                rtMpWinRefreshGip(); \
+        } \
+        else \
+            pGip = NULL; \
+    } else do { } while (0)
+#else
+# define RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP() do { } while (0)
+#endif
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Initialize once. */
+static RTONCE                                       g_MpInitOnce = RTONCE_INITIALIZER;
+#ifdef IPRT_WITH_GIP_MP_INFO
+/** Initialize once using GIP. */
+static RTONCE                                       g_MpInitOnceGip = RTONCE_INITIALIZER;
+#endif
+
+static decltype(GetMaximumProcessorCount)          *g_pfnGetMaximumProcessorCount;
+//static decltype(GetActiveProcessorCount)           *g_pfnGetActiveProcessorCount;
+static decltype(GetCurrentProcessorNumber)         *g_pfnGetCurrentProcessorNumber;
+static decltype(GetCurrentProcessorNumberEx)       *g_pfnGetCurrentProcessorNumberEx;
+static decltype(GetLogicalProcessorInformation)    *g_pfnGetLogicalProcessorInformation;
+static decltype(GetLogicalProcessorInformationEx)  *g_pfnGetLogicalProcessorInformationEx;
+
+
+/** The required buffer size for getting group relations. */
+static uint32_t     g_cbRtMpWinGrpRelBuf;
+/** The max number of CPUs (RTMpGetCount). */
+static uint32_t     g_cRtMpWinMaxCpus;
+/** The max number of CPU cores (RTMpGetCoreCount). */
+static uint32_t     g_cRtMpWinMaxCpuCores;
+/** The max number of groups. */
+static uint32_t     g_cRtMpWinMaxCpuGroups;
+/** The number of active CPUs the last time we checked. */
+static uint32_t volatile g_cRtMpWinActiveCpus;
+/** Static per group info.
+ * @remarks  With 256 entries this takes up 33KB.
+ * @sa g_aRtMpNtCpuGroups */
+static struct
+{
+    /** The max CPUs in the group. */
+    uint16_t    cMaxCpus;
+    /** The number of active CPUs at the time of initialization. */
+    uint16_t    cActiveCpus;
+    /** CPU set indexes for each CPU in the group. */
+    int16_t     aidxCpuSetMembers[64];
+}                   g_aRtMpWinCpuGroups[256];
+/** Maps CPU set indexes to RTCPUID.
+ * @sa g_aidRtMpNtByCpuSetIdx  */
+RTCPUID             g_aidRtMpWinByCpuSetIdx[RTCPUSET_MAX_CPUS];
+
+
+/**
+ * @callback_method_impl{FNRTONCE,
+ *      Resolves dynamic imports and initializes globals.}
+ */
+static DECLCALLBACK(int32_t) rtMpWinInitOnce(void *pvUser)
+{
+    RT_NOREF(pvUser);
+
+    Assert(g_WinOsInfoEx.dwOSVersionInfoSize != 0);
+    Assert(g_hModKernel32 != NULL);
+
+    /*
+     * Resolve dynamic APIs.
+     */
+#define RESOLVE_API(a_szMod, a_FnName) \
+        do { \
+            RT_CONCAT(g_pfn,a_FnName) = (decltype(a_FnName) *)GetProcAddress(g_hModKernel32, #a_FnName); \
+        } while (0)
+    RESOLVE_API("kernel32.dll", GetMaximumProcessorCount);
+    //RESOLVE_API("kernel32.dll", GetActiveProcessorCount); - slow :/
+    RESOLVE_API("kernel32.dll", GetCurrentProcessorNumber);
+    RESOLVE_API("kernel32.dll", GetCurrentProcessorNumberEx);
+    RESOLVE_API("kernel32.dll", GetLogicalProcessorInformation);
+    RESOLVE_API("kernel32.dll", GetLogicalProcessorInformationEx);
+
+    /*
+     * Reset globals.
+     */
+    for (unsigned i = 0; i < RT_ELEMENTS(g_aidRtMpWinByCpuSetIdx); i++)
+        g_aidRtMpWinByCpuSetIdx[i] = NIL_RTCPUID;
+    for (unsigned idxGroup = 0; idxGroup < RT_ELEMENTS(g_aRtMpWinCpuGroups); idxGroup++)
+    {
+        g_aRtMpWinCpuGroups[idxGroup].cMaxCpus    = 0;
+        g_aRtMpWinCpuGroups[idxGroup].cActiveCpus = 0;
+        for (unsigned idxMember = 0; idxMember < RT_ELEMENTS(g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers); idxMember++)
+            g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = -1;
+    }
+
+    /*
+     * Query group information, partitioning CPU IDs and CPU set indexes.
+     *
+     * We ASSUME the GroupInfo index is the same as the group number.
+     *
+     * We CANNOT ASSUME that the kernel CPU indexes are assigned in any given
+     * way, though they usually are in group order by active processor.  So,
+     * we do that to avoid trouble.  We must use information provided thru GIP
+     * if we want the kernel CPU set indexes.  Even there, the inactive CPUs
+     * wont have sensible indexes.  Sigh.
+     *
+     * We try to assign IDs to inactive CPUs in the same manner as mp-r0drv-nt.cpp
+     *
+     * Note! We will die (AssertFatal) if there are too many processors!
+     */
+    union
+    {
+        SYSTEM_INFO                                 SysInfo;
+        SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX     Info;
+        uint8_t                                     abPaddingG[  sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX)
+                                                               + sizeof(PROCESSOR_GROUP_INFO) * 256];
+        uint8_t                                     abPaddingC[  sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX)
+                                                               +   (sizeof(PROCESSOR_RELATIONSHIP) + sizeof(GROUP_AFFINITY))
+                                                                 * RTCPUSET_MAX_CPUS];
+    } uBuf;
+    if (g_pfnGetLogicalProcessorInformationEx)
+    {
+        /* Query the information. */
+        DWORD cbData = sizeof(uBuf);
+        AssertFatalMsg(g_pfnGetLogicalProcessorInformationEx(RelationGroup, &uBuf.Info, &cbData) != FALSE,
+                       ("last error = %u, cbData = %u (in %u)\n", GetLastError(), cbData, sizeof(uBuf)));
+        AssertFatalMsg(uBuf.Info.Relationship == RelationGroup,
+                       ("Relationship = %u, expected %u!\n", uBuf.Info.Relationship, RelationGroup));
+        AssertFatalMsg(uBuf.Info.Group.MaximumGroupCount <= RT_ELEMENTS(g_aRtMpWinCpuGroups),
+                       ("MaximumGroupCount is %u, we only support up to %u!\n",
+                        uBuf.Info.Group.MaximumGroupCount, RT_ELEMENTS(g_aRtMpWinCpuGroups)));
+
+        AssertMsg(uBuf.Info.Group.MaximumGroupCount == uBuf.Info.Group.ActiveGroupCount, /* 2nd assumption mentioned above. */
+                  ("%u vs %u\n", uBuf.Info.Group.MaximumGroupCount, uBuf.Info.Group.ActiveGroupCount));
+        AssertFatal(uBuf.Info.Group.MaximumGroupCount >= uBuf.Info.Group.ActiveGroupCount);
+
+        g_cRtMpWinMaxCpuGroups = uBuf.Info.Group.MaximumGroupCount;
+
+        /* Count max cpus (see mp-r0drv0-nt.cpp) why we don't use GetMaximumProcessorCount(ALL). */
+        uint32_t idxGroup;
+        g_cRtMpWinMaxCpus = 0;
+        for (idxGroup = 0; idxGroup < uBuf.Info.Group.ActiveGroupCount; idxGroup++)
+            g_cRtMpWinMaxCpus += uBuf.Info.Group.GroupInfo[idxGroup].MaximumProcessorCount;
+
+        /* Process the active groups. */
+        uint32_t cActive   = 0;
+        uint32_t cInactive = 0;
+        uint32_t idxCpu    = 0;
+        uint32_t idxCpuSetNextInactive = g_cRtMpWinMaxCpus - 1;
+        for (idxGroup = 0; idxGroup < uBuf.Info.Group.ActiveGroupCount; idxGroup++)
+        {
+            PROCESSOR_GROUP_INFO const *pGroupInfo = &uBuf.Info.Group.GroupInfo[idxGroup];
+            g_aRtMpWinCpuGroups[idxGroup].cMaxCpus    = pGroupInfo->MaximumProcessorCount;
+            g_aRtMpWinCpuGroups[idxGroup].cActiveCpus = pGroupInfo->ActiveProcessorCount;
+            for (uint32_t idxMember = 0; idxMember < pGroupInfo->MaximumProcessorCount; idxMember++)
+            {
+                if (pGroupInfo->ActiveProcessorMask & RT_BIT_64(idxMember))
+                {
+                    g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = idxCpu;
+                    g_aidRtMpWinByCpuSetIdx[idxCpu] = idxCpu;
+                    idxCpu++;
+                    cActive++;
+                }
+                else
+                {
+                    if (idxCpuSetNextInactive >= idxCpu)
+                    {
+                        g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = idxCpuSetNextInactive;
+                        g_aidRtMpWinByCpuSetIdx[idxCpuSetNextInactive] = idxCpuSetNextInactive;
+                        idxCpuSetNextInactive--;
+                    }
+                    cInactive++;
+                }
+            }
+        }
+        g_cRtMpWinActiveCpus = cActive;
+        Assert(cActive + cInactive <= g_cRtMpWinMaxCpus);
+        Assert(idxCpu <= idxCpuSetNextInactive + 1);
+        Assert(idxCpu <= g_cRtMpWinMaxCpus);
+
+        /* Just in case the 2nd assumption doesn't hold true and there are inactive groups. */
+        for (; idxGroup < uBuf.Info.Group.MaximumGroupCount; idxGroup++)
+        {
+            DWORD cMaxMembers = g_pfnGetMaximumProcessorCount(idxGroup);
+            g_aRtMpWinCpuGroups[idxGroup].cMaxCpus    = cMaxMembers;
+            g_aRtMpWinCpuGroups[idxGroup].cActiveCpus = 0;
+            for (uint32_t idxMember = 0; idxMember < cMaxMembers; idxMember++)
+            {
+                if (idxCpuSetNextInactive >= idxCpu)
+                {
+                    g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = idxCpuSetNextInactive;
+                    g_aidRtMpWinByCpuSetIdx[idxCpuSetNextInactive] = idxCpuSetNextInactive;
+                    idxCpuSetNextInactive--;
+                }
+                cInactive++;
+            }
+        }
+        Assert(cActive + cInactive <= g_cRtMpWinMaxCpus);
+        Assert(idxCpu <= idxCpuSetNextInactive + 1);
+    }
+    else
+    {
+        /* Legacy: */
+        GetSystemInfo(&uBuf.SysInfo);
+        g_cRtMpWinMaxCpuGroups              = 1;
+        g_cRtMpWinMaxCpus                   = uBuf.SysInfo.dwNumberOfProcessors;
+        g_aRtMpWinCpuGroups[0].cMaxCpus     = uBuf.SysInfo.dwNumberOfProcessors;
+        g_aRtMpWinCpuGroups[0].cActiveCpus  = uBuf.SysInfo.dwNumberOfProcessors;
+
+        for (uint32_t idxMember = 0; idxMember < uBuf.SysInfo.dwNumberOfProcessors; idxMember++)
+        {
+            g_aRtMpWinCpuGroups[0].aidxCpuSetMembers[idxMember] = idxMember;
+            g_aidRtMpWinByCpuSetIdx[idxMember] = idxMember;
+        }
+    }
+
+    AssertFatalMsg(g_cRtMpWinMaxCpus <= RTCPUSET_MAX_CPUS,
+                   ("g_cRtMpWinMaxCpus=%u (%#x); RTCPUSET_MAX_CPUS=%u\n", g_cRtMpWinMaxCpus, g_cRtMpWinMaxCpus, RTCPUSET_MAX_CPUS));
+
+    g_cbRtMpWinGrpRelBuf = sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX)
+                         + (g_cRtMpWinMaxCpuGroups + 2) * sizeof(PROCESSOR_GROUP_INFO);
+
+    /*
+     * Get information about cores.
+     *
+     * Note! This will only give us info about active processors according to
+     *       MSDN, we'll just have to hope that CPUs aren't hotplugged after we
+     *       initialize here (or that the API consumers doesn't care too much).
+     */
+    /** @todo A hot CPU plug event would be nice. */
+    g_cRtMpWinMaxCpuCores = g_cRtMpWinMaxCpus;
+    if (g_pfnGetLogicalProcessorInformationEx)
+    {
+        /* Query the information. */
+        DWORD cbData = sizeof(uBuf);
+        AssertFatalMsg(g_pfnGetLogicalProcessorInformationEx(RelationProcessorCore, &uBuf.Info, &cbData) != FALSE,
+                       ("last error = %u, cbData = %u (in %u)\n", GetLastError(), cbData, sizeof(uBuf)));
+        g_cRtMpWinMaxCpuCores = 0;
+        for (uint32_t off = 0; off < cbData; )
+        {
+            SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *pCur = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *)&uBuf.abPaddingG[off];
+            AssertFatalMsg(pCur->Relationship == RelationProcessorCore,
+                           ("off = %#x, Relationship = %u, expected %u!\n", off, pCur->Relationship, RelationProcessorCore));
+            g_cRtMpWinMaxCpuCores++;
+            off += pCur->Size;
+        }
+
+#if ARCH_BITS == 32
+        if (g_cRtMpWinMaxCpuCores > g_cRtMpWinMaxCpus)
+        {
+            /** @todo WOW64 trouble where the emulation environment has folded the high
+             *        processor masks (63..32) into the low (31..0), hiding some
+             *        processors from us.  Currently we don't deal with that. */
+            g_cRtMpWinMaxCpuCores = g_cRtMpWinMaxCpus;
+        }
+        else
+            AssertStmt(g_cRtMpWinMaxCpuCores > 0, g_cRtMpWinMaxCpuCores = g_cRtMpWinMaxCpus);
+#else
+        AssertStmt(g_cRtMpWinMaxCpuCores > 0 && g_cRtMpWinMaxCpuCores <= g_cRtMpWinMaxCpus,
+                   g_cRtMpWinMaxCpuCores = g_cRtMpWinMaxCpus);
+#endif
+    }
+    else
+    {
+        /*
+         * Sadly, on XP and Server 2003, even if the API is present, it does not tell us
+         * how many physical cores there are (any package will look like a single core).
+         * That is worse than not using the API at all, so just skip it unless it's Vista+.
+         */
+        if (   g_pfnGetLogicalProcessorInformation
+            && g_WinOsInfoEx.dwPlatformId == VER_PLATFORM_WIN32_NT
+            && g_WinOsInfoEx.dwMajorVersion >= 6)
+        {
+            /* Query the info. */
+            DWORD                                   cbSysProcInfo = _4K;
+            PSYSTEM_LOGICAL_PROCESSOR_INFORMATION   paSysInfo = NULL;
+            BOOL                                    fRc = FALSE;
+            do
+            {
+                cbSysProcInfo = RT_ALIGN_32(cbSysProcInfo, 256);
+                void *pv = RTMemRealloc(paSysInfo, cbSysProcInfo);
+                if (!pv)
+                    break;
+                paSysInfo = (PSYSTEM_LOGICAL_PROCESSOR_INFORMATION)pv;
+                fRc = g_pfnGetLogicalProcessorInformation(paSysInfo, &cbSysProcInfo);
+            } while (!fRc && GetLastError() == ERROR_INSUFFICIENT_BUFFER);
+            if (fRc)
+            {
+                /* Count the cores in the result. */
+                g_cRtMpWinMaxCpuCores = 0;
+                uint32_t i = cbSysProcInfo / sizeof(paSysInfo[0]);
+                while (i-- > 0)
+                    if (paSysInfo[i].Relationship == RelationProcessorCore)
+                        g_cRtMpWinMaxCpuCores++;
+
+                AssertStmt(g_cRtMpWinMaxCpuCores > 0 && g_cRtMpWinMaxCpuCores <= g_cRtMpWinMaxCpus,
+                           g_cRtMpWinMaxCpuCores = g_cRtMpWinMaxCpus);
+            }
+            RTMemFree(paSysInfo);
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+#ifdef IPRT_WITH_GIP_MP_INFO
+/**
+ * @callback_method_impl{FNRTONCE, Updates globals with information from GIP.}
+ */
+static DECLCALLBACK(int32_t) rtMpWinInitOnceGip(void *pvUser)
+{
+    RT_NOREF(pvUser);
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+
+    PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
+    if (   pGip
+        && pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC)
+    {
+        /*
+         * Update globals.
+         */
+        if (g_cRtMpWinMaxCpus != pGip->cPossibleCpus)
+            g_cRtMpWinMaxCpus = pGip->cPossibleCpus;
+        if (g_cRtMpWinActiveCpus != pGip->cOnlineCpus)
+            g_cRtMpWinActiveCpus = pGip->cOnlineCpus;
+        Assert(g_cRtMpWinMaxCpuGroups == pGip->cPossibleCpuGroups);
+        if (g_cRtMpWinMaxCpuGroups != pGip->cPossibleCpuGroups)
+        {
+            g_cRtMpWinMaxCpuGroups = pGip->cPossibleCpuGroups;
+            g_cbRtMpWinGrpRelBuf   = sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX)
+                                   + (g_cRtMpWinMaxCpuGroups + 2) * sizeof(PROCESSOR_GROUP_INFO);
+        }
+
+        /*
+         * Update CPU set IDs.
+         */
+        for (unsigned i = g_cRtMpWinMaxCpus; i < RT_ELEMENTS(g_aidRtMpWinByCpuSetIdx); i++)
+            g_aidRtMpWinByCpuSetIdx[i] = NIL_RTCPUID;
+
+        unsigned const cbGip = pGip->cPages * PAGE_SIZE;
+        for (uint32_t idxGroup = 0; idxGroup < g_cRtMpWinMaxCpuGroups; idxGroup++)
+        {
+            uint32_t idxMember;
+            uint32_t offCpuGroup = pGip->aoffCpuGroup[idxGroup];
+            if (offCpuGroup < cbGip)
+            {
+                PSUPGIPCPUGROUP pGipCpuGrp  = (PSUPGIPCPUGROUP)((uintptr_t)pGip + offCpuGroup);
+                uint32_t        cMaxMembers = pGipCpuGrp->cMaxMembers;
+                AssertStmt(cMaxMembers <= RT_ELEMENTS(g_aRtMpWinCpuGroups[0].aidxCpuSetMembers),
+                           cMaxMembers  = RT_ELEMENTS(g_aRtMpWinCpuGroups[0].aidxCpuSetMembers));
+                g_aRtMpWinCpuGroups[idxGroup].cMaxCpus     = cMaxMembers;
+                g_aRtMpWinCpuGroups[idxGroup].cActiveCpus  = RT_MIN(pGipCpuGrp->cMembers, cMaxMembers);
+
+                for (idxMember = 0; idxMember < cMaxMembers; idxMember++)
+                {
+                    int16_t idxSet = pGipCpuGrp->aiCpuSetIdxs[idxMember];
+                    g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = idxSet;
+                    if ((unsigned)idxSet < RT_ELEMENTS(g_aidRtMpWinByCpuSetIdx))
+# ifdef IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER
+                        g_aidRtMpWinByCpuSetIdx[idxSet] = RTMPCPUID_FROM_GROUP_AND_NUMBER(idxGroup, idxMember);
+# else
+                        g_aidRtMpWinByCpuSetIdx[idxSet] = idxSet;
+# endif
+                }
+            }
+            else
+                idxMember = 0;
+            for (; idxMember < RT_ELEMENTS(g_aRtMpWinCpuGroups[0].aidxCpuSetMembers); idxMember++)
+                g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = -1;
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Refreshes globals from GIP after one or more CPUs were added.
+ *
+ * There are potential races here.  We might race other threads and we may race
+ * more CPUs being added.
+ */
+static void rtMpWinRefreshGip(void)
+{
+    PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
+    if (   pGip
+        && pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC)
+    {
+        /*
+         * Since CPUs cannot be removed, we only have to update the IDs and
+         * indexes of CPUs that we think are inactive and the group member counts.
+         */
+        for (;;)
+        {
+            unsigned const cbGip          = pGip->cPages * PAGE_SIZE;
+            uint32_t const cGipActiveCpus = pGip->cOnlineCpus;
+            uint32_t const cMyActiveCpus  = ASMAtomicReadU32(&g_cRtMpWinActiveCpus);
+            ASMCompilerBarrier();
+
+            for (uint32_t idxGroup = 0; idxGroup < g_cRtMpWinMaxCpuGroups; idxGroup++)
+            {
+                uint32_t offCpuGroup = pGip->aoffCpuGroup[idxGroup];
+                if (offCpuGroup < cbGip)
+                {
+                    PSUPGIPCPUGROUP pGipCpuGrp  = (PSUPGIPCPUGROUP)((uintptr_t)pGip + offCpuGroup);
+                    uint32_t        cMaxMembers = pGipCpuGrp->cMaxMembers;
+                    AssertStmt(cMaxMembers <= RT_ELEMENTS(g_aRtMpWinCpuGroups[0].aidxCpuSetMembers),
+                               cMaxMembers  = RT_ELEMENTS(g_aRtMpWinCpuGroups[0].aidxCpuSetMembers));
+                    for (uint32_t idxMember = g_aRtMpWinCpuGroups[idxGroup].cActiveCpus; idxMember < cMaxMembers; idxMember++)
+                    {
+                        int16_t idxSet = pGipCpuGrp->aiCpuSetIdxs[idxMember];
+                        g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember] = idxSet;
+                        if ((unsigned)idxSet < RT_ELEMENTS(g_aidRtMpWinByCpuSetIdx))
+# ifdef IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER
+                            g_aidRtMpWinByCpuSetIdx[idxSet] = RTMPCPUID_FROM_GROUP_AND_NUMBER(idxGroup, idxMember);
+# else
+                            g_aidRtMpWinByCpuSetIdx[idxSet] = idxSet;
+# endif
+                    }
+                    g_aRtMpWinCpuGroups[idxGroup].cMaxCpus    = RT_MIN(pGipCpuGrp->cMembers, cMaxMembers);
+                    g_aRtMpWinCpuGroups[idxGroup].cActiveCpus = RT_MIN(pGipCpuGrp->cMembers, cMaxMembers);
+                }
+                else
+                    Assert(g_aRtMpWinCpuGroups[idxGroup].cActiveCpus == 0);
+            }
+
+            ASMCompilerBarrier();
+            if (cGipActiveCpus == pGip->cOnlineCpus)
+                if (ASMAtomicCmpXchgU32(&g_cRtMpWinActiveCpus, cGipActiveCpus, cMyActiveCpus))
+                    break;
+        }
+    }
+}
+
+#endif /* IPRT_WITH_GIP_MP_INFO */
+
+
+/*
+ * Conversion between CPU ID and set index.
+ */
+
+RTDECL(int) RTMpCpuIdToSetIndex(RTCPUID idCpu)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+#ifdef IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER
+    if (idCpu != NIL_RTCPUID)
+        return RTMpSetIndexFromCpuGroupMember(rtMpCpuIdGetGroup(idCpu), rtMpCpuIdGetGroupMember(idCpu));
+    return -1;
+
+#else
+    /* 1:1 mapping, just do range checking. */
+    return idCpu < g_cRtMpWinMaxCpus ? idCpu : -1;
+#endif
+}
+
+
+RTDECL(RTCPUID) RTMpCpuIdFromSetIndex(int iCpu)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    if ((unsigned)iCpu < RT_ELEMENTS(g_aidRtMpWinByCpuSetIdx))
+    {
+        RTCPUID idCpu = g_aidRtMpWinByCpuSetIdx[iCpu];
+
+#if defined(IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER) && defined(RT_STRICT)
+        /* Check the correctness of the mapping table. */
+        RTCPUID idCpuGip = NIL_RTCPUID;
+        if (   pGip
+            && (unsigned)iCpu < RT_ELEMENTS(pGip->aiCpuFromCpuSetIdx))
+        {
+            unsigned idxSupCpu = pGip->aiCpuFromCpuSetIdx[idxGuess];
+            if (idxSupCpu < pGip->cCpus)
+                if (pGip->aCPUs[idxSupCpu].enmState != SUPGIPCPUSTATE_INVALID)
+                    idCpuGip = pGip->aCPUs[idxSupCpu].idCpu;
+        }
+        AssertMsg(idCpu == idCpuGip, ("table:%#x  gip:%#x\n", idCpu, idCpuGip));
+#endif
+
+        return idCpu;
+    }
+    return NIL_RTCPUID;
+}
+
+
+RTDECL(int) RTMpSetIndexFromCpuGroupMember(uint32_t idxGroup, uint32_t idxMember)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    if (idxGroup < g_cRtMpWinMaxCpuGroups)
+        if (idxMember < g_aRtMpWinCpuGroups[idxGroup].cMaxCpus)
+            return g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember];
+    return -1;
+}
+
+
+RTDECL(uint32_t) RTMpGetCpuGroupCounts(uint32_t idxGroup, uint32_t *pcActive)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    if (idxGroup < g_cRtMpWinMaxCpuGroups)
+    {
+        if (pcActive)
+            *pcActive = g_aRtMpWinCpuGroups[idxGroup].cActiveCpus;
+        return g_aRtMpWinCpuGroups[idxGroup].cMaxCpus;
+    }
+    if (pcActive)
+        *pcActive = 0;
+    return 0;
+}
+
+
+RTDECL(uint32_t) RTMpGetMaxCpuGroupCount(void)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    return g_cRtMpWinMaxCpuGroups;
+}
+
+
+
+/*
+ * Get current CPU.
+ */
+
+RTDECL(RTCPUID) RTMpCpuId(void)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    PROCESSOR_NUMBER ProcNum;
+    ProcNum.Group = 0;
+    ProcNum.Number = 0xff;
+    if (g_pfnGetCurrentProcessorNumberEx)
+        g_pfnGetCurrentProcessorNumberEx(&ProcNum);
+    else if (g_pfnGetCurrentProcessorNumber)
+    {
+        DWORD iCpu = g_pfnGetCurrentProcessorNumber();
+        Assert(iCpu < g_cRtMpWinMaxCpus);
+        ProcNum.Number = iCpu;
+    }
+    else
+    {
+#if defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
+        ProcNum.Number = ASMGetApicId();
+#else
+# error "Not ported to this architecture."
+        return NIL_RTCPUID;
+#endif
+    }
+
+#ifdef IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER
+    return RTMPCPUID_FROM_GROUP_AND_NUMBER(ProcNum.Group, ProcNum.Number);
+#else
+    return RTMpSetIndexFromCpuGroupMember(ProcNum.Group, ProcNum.Number);
+#endif
+}
+
+
+/*
+ * Possible CPUs and cores.
+ */
+
+RTDECL(RTCPUID) RTMpGetMaxCpuId(void)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+#ifdef IPRT_WITH_RTCPUID_AS_GROUP_AND_NUMBER
+    return RTMPCPUID_FROM_GROUP_AND_NUMBER(g_cRtMpWinMaxCpuGroups - 1,
+                                           g_aRtMpWinCpuGroups[g_cRtMpWinMaxCpuGroups - 1].cMaxCpus - 1);
+#else
+    return g_cRtMpWinMaxCpus - 1;
+#endif
+}
+
+
+RTDECL(bool) RTMpIsCpuPossible(RTCPUID idCpu)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    /* Any CPU between 0 and g_cRtMpWinMaxCpus are possible. */
+    return idCpu < g_cRtMpWinMaxCpus;
+}
+
+
+RTDECL(PRTCPUSET) RTMpGetSet(PRTCPUSET pSet)
+{
+    RTCPUID iCpu = RTMpGetCount();
+    RTCpuSetEmpty(pSet);
+    while (iCpu-- > 0)
+        RTCpuSetAddByIndex(pSet, iCpu);
+    return pSet;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCount(void)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    return g_cRtMpWinMaxCpus;
+}
+
+
+RTDECL(RTCPUID) RTMpGetCoreCount(void)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+    RTMPWIN_UPDATE_GIP_GLOBALS();
+
+    return g_cRtMpWinMaxCpuCores;
+}
+
+
+/*
+ * Online CPUs and cores.
+ */
+
+RTDECL(PRTCPUSET) RTMpGetOnlineSet(PRTCPUSET pSet)
+{
+    RTOnce(&g_MpInitOnce, rtMpWinInitOnce, NULL);
+
+#ifdef IPRT_WITH_GIP_MP_INFO
+    RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP();
+    if (pGip)
+    {
+        *pSet = pGip->OnlineCpuSet;
+        return pSet;
+    }
+#endif
+
+    if (g_pfnGetLogicalProcessorInformationEx)
+    {
+        /*
+         * Get the group relation info.
+         *
+         * In addition to the ASSUMPTIONS that are documented in rtMpWinInitOnce,
+         * we ASSUME that PROCESSOR_GROUP_INFO::MaximumProcessorCount gives the
+         * active processor mask width.
+         */
+        /** @todo this is not correct for WOW64   */
+        DWORD                                    cbInfo = g_cbRtMpWinGrpRelBuf;
+        SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *pInfo = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *)alloca(cbInfo);
+        AssertFatalMsg(g_pfnGetLogicalProcessorInformationEx(RelationGroup, pInfo, &cbInfo) != FALSE,
+                       ("last error = %u, cbInfo = %u (in %u)\n", GetLastError(), cbInfo, g_cbRtMpWinGrpRelBuf));
+        AssertFatalMsg(pInfo->Relationship == RelationGroup,
+                       ("Relationship = %u, expected %u!\n", pInfo->Relationship, RelationGroup));
+        AssertFatalMsg(pInfo->Group.MaximumGroupCount == g_cRtMpWinMaxCpuGroups,
+                       ("MaximumGroupCount is %u, expected %u!\n", pInfo->Group.MaximumGroupCount, g_cRtMpWinMaxCpuGroups));
+
+        RTCpuSetEmpty(pSet);
+        for (uint32_t idxGroup = 0; idxGroup < pInfo->Group.MaximumGroupCount; idxGroup++)
+        {
+            Assert(pInfo->Group.GroupInfo[idxGroup].MaximumProcessorCount == g_aRtMpWinCpuGroups[idxGroup].cMaxCpus);
+            Assert(pInfo->Group.GroupInfo[idxGroup].ActiveProcessorCount  <= g_aRtMpWinCpuGroups[idxGroup].cMaxCpus);
+
+            KAFFINITY fActive = pInfo->Group.GroupInfo[idxGroup].ActiveProcessorMask;
+            if (fActive != 0)
+            {
+#ifdef RT_STRICT
+                uint32_t    cMembersLeft = pInfo->Group.GroupInfo[idxGroup].ActiveProcessorCount;
+#endif
+                int const   cMembers  = g_aRtMpWinCpuGroups[idxGroup].cMaxCpus;
+                for (int idxMember = 0; idxMember < cMembers; idxMember++)
+                {
+                    if (fActive & 1)
+                    {
+#ifdef RT_STRICT
+                        cMembersLeft--;
+#endif
+                        RTCpuSetAddByIndex(pSet, g_aRtMpWinCpuGroups[idxGroup].aidxCpuSetMembers[idxMember]);
+                        fActive >>= 1;
+                        if (!fActive)
+                            break;
+                    }
+                    else
+                    {
+                        fActive >>= 1;
+                    }
+                }
+                Assert(cMembersLeft == 0);
+            }
+            else
+                Assert(pInfo->Group.GroupInfo[idxGroup].ActiveProcessorCount == 0);
+        }
+
+        return pSet;
+    }
+
+    /*
+     * Legacy fallback code.
+     */
+    SYSTEM_INFO SysInfo;
+    GetSystemInfo(&SysInfo);
+    return RTCpuSetFromU64(pSet, SysInfo.dwActiveProcessorMask);
+}
+
+
+RTDECL(bool) RTMpIsCpuOnline(RTCPUID idCpu)
+{
+    RTCPUSET Set;
+    return RTCpuSetIsMember(RTMpGetOnlineSet(&Set), idCpu);
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCount(void)
+{
+#ifdef IPRT_WITH_GIP_MP_INFO
+    RTMPWIN_UPDATE_GIP_GLOBALS_AND_GET_PGIP();
+    if (pGip)
+        return pGip->cOnlineCpus;
+#endif
+
+    RTCPUSET Set;
+    RTMpGetOnlineSet(&Set);
+    return RTCpuSetCount(&Set);
+}
+
+
+RTDECL(RTCPUID) RTMpGetOnlineCoreCount(void)
+{
+    /** @todo this isn't entirely correct, but whatever. */
+    return RTMpGetCoreCount();
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdErr-win.cpp b/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdErr-win.cpp
new file mode 100644
index 00000000..5f74b4f5
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdErr-win.cpp
@@ -0,0 +1,57 @@
+/* $Id: nocrt-RTLogWriteStdErr-win.cpp $ */
+/** @file
+ * IPRT - Log To StdErr, Windows no-CRT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/log.h>
+#include "internal/iprt.h"
+
+#include <iprt/win/windows.h>
+
+
+RTDECL(void) RTLogWriteStdErr(const char *pch, size_t cb)
+{
+    HANDLE hStdErr = GetStdHandle(STD_ERROR_HANDLE);
+    if (hStdErr != NULL && hStdErr != INVALID_HANDLE_VALUE)
+    {
+        DWORD cbIgn; /* NT3.1 requires the return size parameter. */
+        WriteFile(hStdErr, pch, (DWORD)cb, &cbIgn, NULL); /** @todo do we need to translate \\n to \\r\\n? */
+    }
+}
+RT_EXPORT_SYMBOL(RTLogWriteStdErr);
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdOut-win.cpp b/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdOut-win.cpp
new file mode 100644
index 00000000..56e29134
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-RTLogWriteStdOut-win.cpp
@@ -0,0 +1,58 @@
+/* $Id: nocrt-RTLogWriteStdOut-win.cpp $ */
+/** @file
+ * IPRT - Log To StdOut, Windows no-CRT.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/log.h>
+#include "internal/iprt.h"
+
+#include <iprt/win/windows.h>
+
+
+RTDECL(void) RTLogWriteStdOut(const char *pch, size_t cb)
+{
+    /** @todo should flush the stdout stream first... */
+    HANDLE hStdErr = GetStdHandle(STD_OUTPUT_HANDLE);
+    if (hStdErr != NULL && hStdErr != INVALID_HANDLE_VALUE)
+    {
+        DWORD cbIgn; /* NT3.1 requires the return size parameter. */
+        WriteFile(hStdErr, pch, (DWORD)cb, &cbIgn, NULL); /** @todo do we need to translate \\n to \\r\\n? */
+    }
+}
+RT_EXPORT_SYMBOL(RTLogWriteStdOut);
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-WinMainCRTStartup-win.asm b/src/VBox/Runtime/r3/win/nocrt-WinMainCRTStartup-win.asm
new file mode 100644
index 00000000..1943ad69
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-WinMainCRTStartup-win.asm
@@ -0,0 +1,44 @@
+; $Id: nocrt-WinMainCRTStartup-win.asm $
+;; @file
+; IPRT - Alias WinMainCRTStartup to CustomMainEntrypoint in nocrt-startup-exe-win.cpp.
+;
+
+;
+; Copyright (C) 2022-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "iprt/asmdefs.mac"
+
+extern  NAME(CustomMainEntrypoint)
+BEGINPROC WinMainCRTStartup
+        jmp     NAME(CustomMainEntrypoint)
+ENDPROC   WinMainCRTStartup
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-alloc-win.cpp b/src/VBox/Runtime/r3/win/nocrt-alloc-win.cpp
new file mode 100644
index 00000000..128b58df
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-alloc-win.cpp
@@ -0,0 +1,115 @@
+/* $Id: nocrt-alloc-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - Basic allocators, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/mem.h>
+
+#include <iprt/nt/nt-and-windows.h>
+
+
+#undef RTMemTmpFree
+RTDECL(void) RTMemTmpFree(void *pv)
+{
+    HeapFree(GetProcessHeap(), 0, pv);
+}
+
+
+#undef RTMemFree
+RTDECL(void) RTMemFree(void *pv)
+{
+    HeapFree(GetProcessHeap(), 0, pv);
+}
+
+
+#undef RTMemTmpAllocTag
+RTDECL(void *) RTMemTmpAllocTag(size_t cb, const char *pszTag)
+{
+    RT_NOREF(pszTag);
+    return HeapAlloc(GetProcessHeap(), 0, cb);
+}
+
+
+#undef RTMemTmpAllocZTag
+RTDECL(void *) RTMemTmpAllocZTag(size_t cb, const char *pszTag)
+{
+    RT_NOREF(pszTag);
+    return HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cb);
+}
+
+
+#undef RTMemAllocTag
+RTDECL(void *) RTMemAllocTag(size_t cb, const char *pszTag)
+{
+    RT_NOREF(pszTag);
+    return HeapAlloc(GetProcessHeap(), 0, cb);
+}
+
+
+#undef RTMemAllocZTag
+RTDECL(void *) RTMemAllocZTag(size_t cb, const char *pszTag)
+{
+    RT_NOREF(pszTag);
+    return HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cb);
+}
+
+
+#undef RTMemAllocVarTag
+RTDECL(void *) RTMemAllocVarTag(size_t cbUnaligned, const char *pszTag)
+{
+    return RTMemAllocTag(cbUnaligned, pszTag);
+}
+
+
+#undef RTMemAllocZVarTag
+RTDECL(void *) RTMemAllocZVarTag(size_t cbUnaligned, const char *pszTag)
+{
+    return RTMemAllocZTag(cbUnaligned, pszTag);
+}
+
+
+#undef RTMemReallocTag
+RTDECL(void *) RTMemReallocTag(void *pvOld, size_t cbNew, const char *pszTag)
+{
+    RT_NOREF(pszTag);
+    if (pvOld)
+        return HeapReAlloc(GetProcessHeap(), 0, pvOld, cbNew);
+    return HeapAlloc(GetProcessHeap(), 0, cbNew);
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-atexit-win.asm b/src/VBox/Runtime/r3/win/nocrt-atexit-win.asm
new file mode 100644
index 00000000..881463ec
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-atexit-win.asm
@@ -0,0 +1,44 @@
+; $Id: nocrt-atexit-win.asm $
+;; @file
+; IPRT - Alias atexit to rtnocrt_atexit in nocrt-startup-exe-win.cpp.
+;
+
+;
+; Copyright (C) 2022-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "iprt/asmdefs.mac"
+
+extern  NAME(nocrt_atexit)
+BEGINPROC atexit
+        jmp     NAME(nocrt_atexit)
+ENDPROC   atexit
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-fatal-write-win.cpp b/src/VBox/Runtime/r3/win/nocrt-fatal-write-win.cpp
new file mode 100644
index 00000000..c9bfa1b4
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-fatal-write-win.cpp
@@ -0,0 +1,150 @@
+/* $Id: nocrt-fatal-write-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - Fatal Message Writing Primitives, Windows.
+ */
+
+/*
+ * Copyright (C) 2022-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+
+#include <iprt/win/windows.h>
+#include <iprt/string.h>
+
+
+/** @todo invent some kind of weak linking with the debug and release
+ *        loggers, e.g. theset some innocent function we can call to do
+ *        logging and we'll call it if it isn't NULL. */
+
+void rtNoCrtFatalWrite(const char *pchMsg, size_t cchMsg)
+{
+    DWORD cbIgn;
+    WriteFile(GetStdHandle(STD_ERROR_HANDLE), pchMsg, (DWORD)cchMsg, &cbIgn, NULL);
+}
+
+
+void rtNoCrtFatalWriteBegin(const char *pchMsg, size_t cchMsg)
+{
+    rtNoCrtFatalWrite(pchMsg, cchMsg);
+}
+
+
+void rtNoCrtFatalWriteEnd(const char *pchMsg, size_t cchMsg)
+{
+    rtNoCrtFatalWrite(pchMsg, cchMsg);
+}
+
+
+void rtNoCrtFatalWritePtr(void const *pv)
+{
+    char    szValue[128];
+#if ARCH_BITS == 64
+    ssize_t cchValue = RTStrFormatU64(szValue, sizeof(szValue), (uintptr_t)pv, 16, 16, 16, RTSTR_F_WIDTH | RTSTR_F_64BIT);
+#elif ARCH_BITS == 32
+    ssize_t cchValue = RTStrFormatU32(szValue, sizeof(szValue), (uintptr_t)pv, 16,  8,  8, RTSTR_F_WIDTH | RTSTR_F_32BIT);
+#else
+# error ARCH_BITS
+#endif
+    rtNoCrtFatalWrite(szValue, (size_t)cchValue);
+}
+
+
+void rtNoCrtFatalWriteX64(uint64_t uValue)
+{
+    char    szValue[128];
+    ssize_t cchValue = RTStrFormatU64(szValue, sizeof(szValue), uValue, 16, 0, 0, RTSTR_F_SPECIAL | RTSTR_F_64BIT);
+    rtNoCrtFatalWrite(szValue, (size_t)cchValue);
+}
+
+
+void rtNoCrtFatalWriteX32(uint32_t uValue)
+{
+    char    szValue[128];
+    ssize_t cchValue = RTStrFormatU32(szValue, sizeof(szValue), uValue, 16, 0, 0, RTSTR_F_SPECIAL | RTSTR_F_32BIT);
+    rtNoCrtFatalWrite(szValue, (size_t)cchValue);
+}
+
+
+void rtNoCrtFatalWriteRc(int rc)
+{
+    char    szValue[128];
+    ssize_t cchValue = RTStrFormatU32(szValue, sizeof(szValue), rc, 10, 0, 0, RTSTR_F_32BIT | RTSTR_F_VALSIGNED);
+    rtNoCrtFatalWrite(szValue, (size_t)cchValue);
+}
+
+void rtNoCrtFatalWriteWinRc(uint32_t rc)
+{
+    char    szValue[168];
+    ssize_t cchValue = RTStrFormatU32(szValue, sizeof(szValue), rc, 10, 0, 0, RTSTR_F_32BIT);
+    szValue[cchValue++] = ' ';
+    szValue[cchValue++] = '(';
+    cchValue += RTStrFormatU32(&szValue[cchValue], sizeof(szValue) - cchValue, rc, 16, 0, 0, RTSTR_F_32BIT | RTSTR_F_SPECIAL);
+    szValue[cchValue++] = ')';
+    rtNoCrtFatalWrite(szValue, (size_t)cchValue);
+}
+
+
+void rtNoCrtFatalWriteStr(const char *pszString)
+{
+    if (RT_VALID_PTR(pszString))
+    {
+        size_t cch = 0;
+        while (pszString[cch] != '\0')
+            cch++;
+        rtNoCrtFatalWrite(pszString, cch);
+    }
+    else
+    {
+        rtNoCrtFatalWrite(RT_STR_TUPLE("<pszString="));
+        rtNoCrtFatalWritePtr(pszString);
+        rtNoCrtFatalWrite(RT_STR_TUPLE(">"));
+    }
+}
+
+
+void rtNoCrtFatalMsg(const char *pchMsg, size_t cchMsg)
+{
+    rtNoCrtFatalWriteBegin(pchMsg, cchMsg);
+    rtNoCrtFatalWriteEnd(RT_STR_TUPLE(""));
+}
+
+
+void rtNoCrtFatalMsgWithRc(const char *pchMsg, size_t cchMsg, int rc)
+{
+    rtNoCrtFatalWriteBegin(pchMsg, cchMsg);
+    rtNoCrtFatalWriteRc(rc);
+    rtNoCrtFatalWriteEnd(RT_STR_TUPLE("\r\n"));
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-mainCRTStartup-win.asm b/src/VBox/Runtime/r3/win/nocrt-mainCRTStartup-win.asm
new file mode 100644
index 00000000..54651dd1
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-mainCRTStartup-win.asm
@@ -0,0 +1,44 @@
+; $Id: nocrt-mainCRTStartup-win.asm $
+;; @file
+; IPRT - Alias mainCRTStartup to CustomMainEntrypoint in nocrt-startup-exe-win.cpp.
+;
+
+;
+; Copyright (C) 2022-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "iprt/asmdefs.mac"
+
+extern  NAME(CustomMainEntrypoint)
+BEGINPROC mainCRTStartup
+        jmp     NAME(CustomMainEntrypoint)
+ENDPROC   mainCRTStartup
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-startup-common-win.cpp b/src/VBox/Runtime/r3/win/nocrt-startup-common-win.cpp
new file mode 100644
index 00000000..598339db
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-startup-common-win.cpp
@@ -0,0 +1,211 @@
+/* $Id: nocrt-startup-common-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - Common Windows startup code.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+#include "internal/process.h"
+
+#include <iprt/nt/nt-and-windows.h>
+#ifndef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+# include <iprt/assert.h>
+#endif
+#include <iprt/getopt.h>
+#include <iprt/message.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include "internal/compiler-vcc.h"
+#include "internal/process.h"
+
+
+#ifdef RT_ARCH_X86
+/**
+ * NT 3.1 does not know about the IMAGE_SECTION_HEADER::Misc.VirtualSize field
+ * and will therefore not handle merging initialized and uninitialized data into
+ * the same section.
+ *
+ * We work around this by manually zeroing the uninitialized data before any
+ * other code has been executed.
+ */
+void rtVccWinInitBssOnNt3(void *pvImageBase)
+{
+    /* We are called really early on, so we must figure out the NT version
+       on our own.  It doesn't have to be all that accurate, though, as only
+       NT 3.10 is affected (3.50 isn't). */
+    DWORD const dwRawVer  = GetVersion();
+    DWORD const uMajorVer = RT_BYTE1(dwRawVer);
+    DWORD const uMinorVer = RT_BYTE2(dwRawVer);
+    if (uMajorVer != 3 || uMinorVer >= 50)
+        return;
+
+    /*
+     * Locate the NT headers.
+     */
+    PIMAGE_NT_HEADERS   pNtHdrs;
+    PIMAGE_DOS_HEADER   pDosHdr = (PIMAGE_DOS_HEADER)pvImageBase;
+    if (pDosHdr->e_magic == IMAGE_DOS_SIGNATURE)
+        pNtHdrs = (PIMAGE_NT_HEADERS)((uintptr_t)pvImageBase + pDosHdr->e_lfanew);
+    else
+        pNtHdrs = (PIMAGE_NT_HEADERS)pvImageBase;
+    if (pNtHdrs->Signature == IMAGE_NT_SIGNATURE)
+    {
+        /*
+         * Locate the section table and walk thru it, memsetting anything that
+         * wasn't loaded from the file.
+         */
+        PIMAGE_SECTION_HEADER paSHdrs = (PIMAGE_SECTION_HEADER)(  (uintptr_t)&pNtHdrs->OptionalHeader
+                                                                + pNtHdrs->FileHeader.SizeOfOptionalHeader);
+        uint32_t const        cSections = pNtHdrs->FileHeader.NumberOfSections;
+        for (uint32_t i = 0; i < cSections; i++)
+        {
+            if (paSHdrs[i].Misc.VirtualSize > paSHdrs[i].SizeOfRawData)
+            {
+                /* ASSUMES VirtualAddress is still an RVAs */
+                uint8_t       *pbToZero = (uint8_t *)pvImageBase + paSHdrs[i].VirtualAddress + paSHdrs[i].SizeOfRawData;
+                uint32_t const cbToZero = paSHdrs[i].Misc.VirtualSize - paSHdrs[i].SizeOfRawData;
+
+# if 0 /* very very crude debugging */
+                const char *pszHex = "0123456789abcdef";
+                char szMsg[128];
+                char *psz = szMsg;
+                *psz++ = 'd'; *psz++ = 'b'; *psz++ = 'g'; *psz++ = ':'; *psz++ = ' ';
+                for (uint32_t q = 0, u = i; q < 8; q++, u >>= 4)
+                    psz[7 - q] = pszHex[u & 0xf];
+                psz += 8;
+                *psz++ = ':';
+                *psz++ = ' ';
+                for (uint32_t q = 0, u = (uint32_t)pbToZero; q < 8; q++, u >>= 4)
+                    psz[7 - q] = pszHex[u & 0xf];
+                psz += 8;
+                *psz++ = ' ';
+                *psz++ = 'L';
+                *psz++ = 'B';
+                *psz++ = ' ';
+                for (uint32_t q = 0, u = cbToZero; q < 8; q++, u >>= 4)
+                    psz[7 - q] = pszHex[u & 0xf];
+                psz += 8;
+                *psz++ = ' ';
+                for (uint32_t q = 0; q < 8; q++)
+                    *psz++ = paSHdrs[i].Name[q] ? paSHdrs[i].Name[q] : ' ';
+                *psz++ = ' '; *psz++ = '/'; *psz++ = ' '; *psz++ = 'v'; *psz++ = 'e'; *psz++ = 'r'; *psz++ = ' ';
+                *psz++ = pszHex[(uMajorVer >> 4) & 0xf];
+                *psz++ = pszHex[uMajorVer & 0xf];
+                *psz++ = '.';
+                *psz++ = pszHex[(uMinorVer >> 4) & 0xf];
+                *psz++ = pszHex[uMinorVer & 0xf];
+                *psz++ = '\r'; *psz++ = '\n';
+                *psz   = '\0';
+                DWORD cbIgn;
+                HANDLE hOut = RTNtCurrentPeb()->ProcessParameters->StandardOutput;
+                if (hOut == NULL || hOut == INVALID_HANDLE_VALUE)
+                    hOut = RTNtCurrentPeb()->ProcessParameters->StandardError;
+                if (hOut == NULL || hOut == INVALID_HANDLE_VALUE)
+                    hOut = RTNtCurrentPeb()->ProcessParameters->ConsoleHandle;
+                if (hOut == NULL || hOut == INVALID_HANDLE_VALUE)
+                    hOut = GetStdHandle(STD_OUTPUT_HANDLE);
+                WriteFile(hOut, szMsg, psz - szMsg, &cbIgn, NULL);
+# endif
+
+                if (paSHdrs[i].Characteristics & IMAGE_SCN_MEM_WRITE)
+                    memset(pbToZero, 0, cbToZero);
+                else
+                {
+                    /* The section is not writable, so temporarily make it writable. */
+                    PVOID pvAligned = pbToZero - ((uintptr_t)pbToZero & PAGE_OFFSET_MASK);
+                    ULONG cbAligned = RT_ALIGN_32(cbToZero + ((uintptr_t)pbToZero & PAGE_OFFSET_MASK), PAGE_SIZE);
+                    ULONG fNewProt  = paSHdrs[i].Characteristics & IMAGE_SCN_MEM_EXECUTE
+                                    ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
+                    ULONG fOldProt  = fNewProt;
+                    NTSTATUS rcNt = NtProtectVirtualMemory(NtCurrentProcess(), &pvAligned, &cbAligned, fNewProt, &fOldProt);
+                    if (NT_SUCCESS(rcNt))
+                    {
+                        memset(pbToZero, 0, cbToZero);
+
+                        rcNt = NtProtectVirtualMemory(NtCurrentProcess(), &pvAligned, &cbAligned, fOldProt, &fNewProt);
+                    }
+                    else
+                        RT_BREAKPOINT();
+                }
+            }
+        }
+    }
+    else
+        RT_BREAKPOINT();
+}
+#endif
+
+
+void rtVccWinInitProcExecPath(void)
+{
+    WCHAR wszPath[RTPATH_MAX];
+    UINT cwcPath = GetModuleFileNameW(NULL, wszPath, RT_ELEMENTS(wszPath));
+    if (cwcPath)
+    {
+        char *pszDst = g_szrtProcExePath;
+        int rc = RTUtf16ToUtf8Ex(wszPath, cwcPath, &pszDst, sizeof(g_szrtProcExePath), &g_cchrtProcExePath);
+        if (RT_SUCCESS(rc))
+        {
+            g_cchrtProcExeDir = g_offrtProcName = RTPathFilename(pszDst) - g_szrtProcExePath;
+            while (   g_cchrtProcExeDir >= 2
+                   && RTPATH_IS_SLASH(g_szrtProcExePath[g_cchrtProcExeDir - 1])
+                   && g_szrtProcExePath[g_cchrtProcExeDir - 2] != ':')
+                g_cchrtProcExeDir--;
+        }
+        else
+        {
+#ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+            RTMsgError("initProcExecPath: RTUtf16ToUtf8Ex failed: %Rrc\n", rc);
+#else
+            rtNoCrtFatalMsgWithRc(RT_STR_TUPLE("initProcExecPath: RTUtf16ToUtf8Ex failed: "), rc);
+#endif
+        }
+    }
+    else
+    {
+#ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+        RTMsgError("initProcExecPath: GetModuleFileNameW failed: %Rhrc\n", GetLastError());
+#else
+        rtNoCrtFatalWriteBegin(RT_STR_TUPLE("initProcExecPath: GetModuleFileNameW failed: "));
+        rtNoCrtFatalWriteWinRc(GetLastError());
+        rtNoCrtFatalWrite(RT_STR_TUPLE("\r\n"));
+#endif
+    }
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-startup-dll-win.cpp b/src/VBox/Runtime/r3/win/nocrt-startup-dll-win.cpp
new file mode 100644
index 00000000..77bf0951
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-startup-dll-win.cpp
@@ -0,0 +1,162 @@
+/* $Id: nocrt-startup-dll-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - Windows EXE startup code.
+ *
+ * @note Does not run static constructors and destructors!
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include "internal/process.h"
+
+#include <iprt/nt/nt-and-windows.h>
+#include <iprt/getopt.h>
+#include <iprt/message.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#ifdef IPRT_NO_CRT
+# include <iprt/asm.h>
+# include <iprt/nocrt/stdlib.h>
+#endif
+
+#include "internal/compiler-vcc.h"
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static volatile int32_t g_cAttached = 0;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+extern "C" BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID pvReserved);
+
+
+DECL_NO_INLINE(static, BOOL) rtVccDllMainForward(HINSTANCE hInstance, DWORD dwReason, LPVOID pvReserved)
+{
+    return DllMain(hInstance, dwReason, pvReserved);
+}
+
+
+
+DECL_NO_INLINE(static, BOOL) rtVccDllMainProcessAttach(HINSTANCE hInstance, LPVOID pvReserved)
+{
+    /*
+     * Initialize the CRT the first time thru.
+     */
+    if (g_cAttached == 0)
+    {
+        rtVccWinInitProcExecPath();
+
+        int rc = rtVccInitializersRunInit();
+        if (RT_FAILURE(rc))
+            return FALSE;
+    }
+    g_cAttached++;
+
+    /*
+     * Call the DllMain function.
+     */
+    BOOL fRet = rtVccDllMainForward(hInstance, DLL_PROCESS_ATTACH, pvReserved);
+
+    /*
+     * On failure, we call the DllMain function again, decrement the init counter
+     * and probably run termination callbacks.
+     */
+    if (!fRet)
+    {
+        rtVccDllMainForward(hInstance, DLL_PROCESS_DETACH, pvReserved);
+        if (--g_cAttached == 0)
+        {
+            rtVccTermRunAtExit();
+            rtVccInitializersRunTerm();
+        }
+    }
+    return fRet;
+}
+
+
+DECL_NO_INLINE(static, BOOL) rtVccDllMainProcessDetach(HINSTANCE hInstance, LPVOID pvReserved)
+{
+    /*
+     * Make sure there isn't an imbalance before calling DllMain and shutting
+     * down our own internals.
+     */
+    if (g_cAttached <= 0)
+        return FALSE;
+
+    /*
+     * Call DllMain.
+     */
+    BOOL fRet = rtVccDllMainForward(hInstance, DLL_PROCESS_DETACH, pvReserved);
+
+    /*
+     * Work g_cAttached and probably do uninitialization.  We'll do this regardless
+     * of what DllMain returned.
+     */
+    if (--g_cAttached == 0)
+    {
+        rtVccTermRunAtExit();
+        rtVccInitializersRunTerm();
+    }
+    return fRet;
+}
+
+
+extern "C" BOOL WINAPI _DllMainCRTStartup(HINSTANCE hInstance, DWORD dwReason, LPVOID pvReserved)
+{
+    switch (dwReason)
+    {
+        case DLL_PROCESS_ATTACH:
+#ifdef RT_ARCH_X86
+            rtVccWinInitBssOnNt3((PVOID)hInstance);
+#endif
+            rtVccInitSecurityCookie(); /* This function must be minimal because of this! */
+            return rtVccDllMainProcessAttach(hInstance, pvReserved);
+
+        case DLL_PROCESS_DETACH:
+            return rtVccDllMainProcessDetach(hInstance, pvReserved);
+
+        default:
+            return rtVccDllMainForward(hInstance, dwReason, pvReserved);
+    }
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-startup-exe-win.cpp b/src/VBox/Runtime/r3/win/nocrt-startup-exe-win.cpp
new file mode 100644
index 00000000..543ea05c
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-startup-exe-win.cpp
@@ -0,0 +1,174 @@
+/* $Id: nocrt-startup-exe-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - Windows EXE startup code.
+ *
+ * @note Does not run static constructors and destructors!
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/nocrt.h"
+#include "internal/process.h"
+
+#include <iprt/nt/nt-and-windows.h>
+#include <iprt/getopt.h>
+#include <iprt/message.h>
+#include <iprt/path.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include "internal/compiler-vcc.h"
+
+
+/*********************************************************************************************************************************
+*   External Symbols                                                                                                             *
+*********************************************************************************************************************************/
+extern int main(int argc, char **argv, char **envp);    /* in program */
+#ifndef IPRT_NO_CRT
+extern DECLHIDDEN(void) InitStdHandles(PRTL_USER_PROCESS_PARAMETERS pParams); /* nocrt-streams-win.cpp */ /** @todo put in header */
+#endif
+
+
+static int rtTerminateProcess(int32_t rcExit, bool fDoAtExit)
+{
+#ifdef IPRT_NO_CRT
+    /*
+     * Run atexit callback in reverse order.
+     */
+    if (fDoAtExit)
+    {
+        rtVccTermRunAtExit();
+        rtVccInitializersRunTerm();
+    }
+#else
+    RT_NOREF(fDoAtExit);
+#endif
+
+    /*
+     * Terminate.
+     */
+    for (;;)
+        NtTerminateProcess(NtCurrentProcess(), rcExit);
+}
+
+
+DECLASM(void) CustomMainEntrypoint(void)
+{
+    /* Looks like might have gotten the PPEB as parameter here before NT4,
+       however, there the EXE entry function clearly takes no parameters.
+       So, we have to retrieve the PEB our selves here. */
+    PPEB_COMMON const pPeb = RTNtCurrentPeb();
+
+    /*
+     * Initialize stuff.
+     */
+#ifdef IPRT_NO_CRT
+# ifdef RT_ARCH_X86
+    rtVccWinInitBssOnNt3(pPeb->ImageBaseAddress);
+# endif
+    rtVccInitSecurityCookie();
+#else
+    InitStdHandles(pPeb->ProcessParameters);
+#endif
+    rtVccWinInitProcExecPath();
+
+    RTEXITCODE rcExit;
+#ifdef IPRT_NO_CRT
+    AssertCompile(sizeof(rcExit) == sizeof(int));
+    rcExit = (RTEXITCODE)rtVccInitializersRunInit();
+    if (rcExit == RTEXITCODE_SUCCESS)
+#endif
+    {
+        /*
+         * Get and convert the command line to argc/argv format.
+         */
+        rcExit = RTEXITCODE_INIT;
+        UNICODE_STRING const *pCmdLine = pPeb->ProcessParameters ? &pPeb->ProcessParameters->CommandLine : NULL;
+        if (pCmdLine)
+        {
+            char *pszCmdLine = NULL;
+            int rc = RTUtf16ToUtf8Ex(pCmdLine->Buffer, pCmdLine->Length / sizeof(WCHAR), &pszCmdLine, 0, NULL);
+            if (RT_SUCCESS(rc))
+            {
+                char **papszArgv;
+                int    cArgs = 0;
+                rc = RTGetOptArgvFromString(&papszArgv, &cArgs, pszCmdLine,
+                                            RTGETOPTARGV_CNV_MODIFY_INPUT | RTGETOPTARGV_CNV_QUOTE_MS_CRT,  NULL);
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * Call the main function.
+                     */
+                    AssertCompile(sizeof(rcExit) == sizeof(int));
+                    rcExit = (RTEXITCODE)main(cArgs, papszArgv, NULL /*envp*/);
+                }
+                else
+#ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+                    RTMsgError("Error parsing command line: %Rrc\n", rc);
+#else
+                    rtNoCrtFatalMsgWithRc(RT_STR_TUPLE("Error parsing command line: "), rc);
+#endif
+            }
+            else
+#ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+                RTMsgError("Failed to convert command line to UTF-8: %Rrc\n", rc);
+#else
+                rtNoCrtFatalMsgWithRc(RT_STR_TUPLE("Failed to convert command line to UTF-8: "), rc);
+#endif
+        }
+        else
+#ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+            RTMsgError("No command line\n");
+#else
+            rtNoCrtFatalMsg(RT_STR_TUPLE("No command line\r\n"));
+#endif
+        rtTerminateProcess(rcExit, true /*fDoAtExit*/);
+    }
+#ifdef IPRT_NO_CRT
+    else
+    {
+# ifdef IPRT_NOCRT_WITHOUT_FATAL_WRITE
+        RTMsgError("A C static initializor failed (%d)\n", rcExit);
+# else
+        rtNoCrtFatalWriteBegin(RT_STR_TUPLE("A C static initializor failed ("));
+        rtNoCrtFatalWriteWinRc(rcExit);
+        rtNoCrtFatalWriteEnd(RT_STR_TUPLE("\r\n"));
+# endif
+        rtTerminateProcess(rcExit, false /*fDoAtExit*/);
+    }
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/win/nocrt-streams-win.cpp b/src/VBox/Runtime/r3/win/nocrt-streams-win.cpp
new file mode 100644
index 00000000..269c9bd2
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/nocrt-streams-win.cpp
@@ -0,0 +1,223 @@
+/* $Id: nocrt-streams-win.cpp $ */
+/** @file
+ * IPRT - No-CRT - minimal stream implementation
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/stream.h>
+
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/ctype.h>
+#include <iprt/file.h>
+#include <iprt/string.h>
+
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct PRINTFBUF
+{
+    HANDLE  hNative;
+    size_t  offBuf;
+    char    szBuf[128];
+} PRINTFBUF;
+
+struct RTSTREAM
+{
+    int     iStream;
+    HANDLE  hNative;
+    RTFILE  hFile;
+};
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#define MAKE_SURE_WE_HAVE_HFILE_RETURN(a_pStream) do { \
+        if ((a_pStream)->hFile != NIL_RTFILE) \
+            break; \
+        int rc = RTFileFromNative(&(a_pStream)->hFile, (uintptr_t)(a_pStream)->hNative); \
+        AssertRCReturn(rc, rc); \
+    } while (0)
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+RTSTREAM g_aStdStreams[3] =
+{
+    { 0, NULL, NIL_RTFILE },
+    { 1, NULL, NIL_RTFILE },
+    { 2, NULL, NIL_RTFILE },
+};
+
+RTSTREAM *g_pStdIn  = &g_aStdStreams[0];
+RTSTREAM *g_pStdOut = &g_aStdStreams[1];
+RTSTREAM *g_pStdErr = &g_aStdStreams[2];
+
+
+
+DECLHIDDEN(void) InitStdHandles(PRTL_USER_PROCESS_PARAMETERS pParams)
+{
+    if (pParams)
+    {
+        g_pStdIn->hNative  = pParams->StandardInput;
+        g_pStdOut->hNative = pParams->StandardOutput;
+        g_pStdErr->hNative = pParams->StandardError;
+    }
+}
+
+
+static void FlushPrintfBuffer(PRINTFBUF *pBuf)
+{
+    if (pBuf->offBuf)
+    {
+        DWORD cbWritten = 0;
+        WriteFile(pBuf->hNative, pBuf->szBuf, (DWORD)pBuf->offBuf, &cbWritten, NULL);
+        pBuf->offBuf   = 0;
+        pBuf->szBuf[0] = '\0';
+    }
+}
+
+
+/** @callback_method_impl{FNRTSTROUTPUT} */
+static DECLCALLBACK(size_t) MyPrintfOutputter(void *pvArg, const char *pachChars, size_t cbChars)
+{
+    PRINTFBUF *pBuf = (PRINTFBUF *)pvArg;
+    if (cbChars != 0)
+    {
+        size_t offSrc = 0;
+        while  (offSrc < cbChars)
+        {
+            size_t cbLeft = sizeof(pBuf->szBuf) - pBuf->offBuf - 1;
+            if (cbLeft > 0)
+            {
+                size_t cbToCopy = RT_MIN(cbChars - offSrc, cbLeft);
+                memcpy(&pBuf->szBuf[pBuf->offBuf], &pachChars[offSrc], cbToCopy);
+                pBuf->offBuf += cbToCopy;
+                pBuf->szBuf[pBuf->offBuf] = '\0';
+                if (cbLeft > cbToCopy)
+                    break;
+                offSrc += cbToCopy;
+            }
+            FlushPrintfBuffer(pBuf);
+        }
+    }
+    else /* Special zero byte write at the end of the formatting. */
+        FlushPrintfBuffer(pBuf);
+    return cbChars;
+}
+
+
+RTR3DECL(int) RTStrmPrintfV(PRTSTREAM pStream, const char *pszFormat, va_list args)
+{
+    PRINTFBUF Buf;
+    Buf.hNative  = pStream->hNative;
+    Buf.offBuf   = 0;
+    Buf.szBuf[0] = '\0';
+
+    return (int)RTStrFormatV(MyPrintfOutputter, &Buf, NULL, NULL, pszFormat, args);
+}
+
+
+RTR3DECL(int) RTStrmPrintf(PRTSTREAM pStream, const char *pszFormat, ...)
+{
+    va_list args;
+    va_start(args, pszFormat);
+    int rc = RTStrmPrintfV(pStream, pszFormat, args);
+    va_end(args);
+    return rc;
+}
+
+
+RTR3DECL(int) RTPrintfV(const char *pszFormat, va_list va)
+{
+    PRINTFBUF Buf;
+    Buf.hNative  = g_pStdOut->hNative;
+    Buf.offBuf   = 0;
+    Buf.szBuf[0] = '\0';
+
+    return (int)RTStrFormatV(MyPrintfOutputter, &Buf, NULL, NULL, pszFormat, va);
+}
+
+
+RTR3DECL(int) RTPrintf(const char *pszFormat, ...)
+{
+    va_list va;
+    va_start(va, pszFormat);
+    int rc = RTPrintfV(pszFormat, va);
+    va_end(va);
+    return rc;
+}
+
+#ifndef IPRT_MINIMAL_STREAM
+
+# if 0
+RTR3DECL(int) RTStrmReadEx(PRTSTREAM pStream, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    MAKE_SURE_WE_HAVE_HFILE_RETURN(pStream);
+    return RTFileRead(pStream->hFile, pvBuf, cbToRead, pcbRead);
+}
+# endif
+
+
+RTR3DECL(int) RTStrmWriteEx(PRTSTREAM pStream, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    MAKE_SURE_WE_HAVE_HFILE_RETURN(pStream);
+    return RTFileWrite(pStream->hFile, pvBuf, cbToWrite, pcbWritten);
+}
+
+
+RTR3DECL(int) RTStrmFlush(PRTSTREAM pStream)
+{
+    MAKE_SURE_WE_HAVE_HFILE_RETURN(pStream);
+    return RTFileFlush(pStream->hFile);
+}
+
+
+RTR3DECL(int) RTStrmSetMode(PRTSTREAM pStream, int fBinary, int fCurrentCodeSet)
+{
+    AssertReturn(fBinary != (int)false, VERR_NOT_IMPLEMENTED);
+    AssertReturn(fCurrentCodeSet <= (int)false, VERR_NOT_IMPLEMENTED);
+    RT_NOREF(pStream);
+    return VINF_SUCCESS;
+}
+
+#endif
diff --git a/src/VBox/Runtime/r3/win/ntdll-mini-implib.def b/src/VBox/Runtime/r3/win/ntdll-mini-implib.def
new file mode 100644
index 00000000..c382847e
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/ntdll-mini-implib.def
@@ -0,0 +1,163 @@
+; $Id: ntdll-mini-implib.def $
+;; @file
+; IPRT - Minimal NTDLL import library defintion file.
+;
+
+;
+; Copyright (C) 2010-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+LIBRARY ntdll.dll
+EXPORTS
+  ; Exported name                           - The name x86 name sought by the linker.
+  ;                                         - This needs to be defined as a symbol, we generate assembly.
+
+    CsrClientCallServer                   ;;= _CsrClientCallServer@16
+
+    NtAlertThread                         ;;= _NtAlertThread@4
+    NtAllocateVirtualMemory               ;;= _NtAllocateVirtualMemory@24
+    NtCancelIoFile                        ;;= _NtCancelIoFile@8
+    NtClearEvent                          ;;= _NtClearEvent@4
+    NtClose                               ;;= _NtClose@4
+    NtCreateEvent                         ;;= _NtCreateEvent@20
+    NtCreateFile                          ;;= _NtCreateFile@44
+    NtCreateSection                       ;;= _NtCreateSection@28
+    NtCreateSymbolicLinkObject            ;;= _NtCreateSymbolicLinkObject@16
+    NtDelayExecution                      ;;= _NtDelayExecution@8
+    NtDeviceIoControlFile                 ;;= _NtDeviceIoControlFile@40
+    NtDuplicateObject                     ;;= _NtDuplicateObject@28
+    NtEnumerateKey                        ;;= _NtEnumerateKey@24
+    NtFlushBuffersFile                    ;;= _NtFlushBuffersFile@8
+    NtFlushVirtualMemory                  ;;= _NtFlushVirtualMemory@16
+    NtFreeVirtualMemory                   ;;= _NtFreeVirtualMemory@16
+    NtGetContextThread                    ;;= _NtGetContextThread@8
+    NtMapViewOfSection                    ;;= _NtMapViewOfSection@40
+    NtOpenDirectoryObject                 ;;= _NtOpenDirectoryObject@12
+    NtOpenEvent                           ;;= _NtOpenEvent@12
+    NtOpenKey                             ;;= _NtOpenKey@12
+    NtOpenProcess                         ;;= _NtOpenProcess@16
+    NtOpenProcessToken                    ;;= _NtOpenProcessToken@12
+    NtOpenSymbolicLinkObject              ;;= _NtOpenSymbolicLinkObject@12
+    NtOpenThread                          ;;= _NtOpenThread@16
+    NtOpenThreadToken                     ;;= _NtOpenThreadToken@16
+    NtProtectVirtualMemory                ;;= _NtProtectVirtualMemory@20
+    NtQueryAttributesFile                 ;;= _NtQueryAttributesFile@8
+    NtQueryDirectoryFile                  ;;= _NtQueryDirectoryFile@44
+    NtQueryDirectoryObject                ;;= _NtQueryDirectoryObject@28
+    NtQueryFullAttributesFile             ;;= _NtQueryFullAttributesFile@8
+    NtQueryEvent                          ;;= _NtQueryEvent@20
+    NtQueryInformationFile                ;;= _NtQueryInformationFile@20
+    NtQueryInformationProcess             ;;= _NtQueryInformationProcess@20
+    NtQueryInformationThread              ;;= _NtQueryInformationThread@20
+    NtQueryInformationToken               ;;= _NtQueryInformationToken@20
+    NtQueryKey                            ;;= _NtQueryKey@20
+    NtQueryObject                         ;;= _NtQueryObject@20
+    NtQuerySection                        ;;= _NtQuerySection@20
+    NtQuerySecurityObject                 ;;= _NtQuerySecurityObject@20
+    NtQuerySymbolicLinkObject             ;;= _NtQuerySymbolicLinkObject@12
+    NtQuerySystemInformation              ;;= _NtQuerySystemInformation@16
+    NtQueryTimerResolution                ;;= _NtQueryTimerResolution@12
+    NtQueryValueKey                       ;;= _NtQueryValueKey@24
+    NtQueryVirtualMemory                  ;;= _NtQueryVirtualMemory@24
+    NtQueryVolumeInformationFile          ;;= _NtQueryVolumeInformationFile@20
+    NtReadFile                            ;;= _NtReadFile@36
+    NtReadVirtualMemory                   ;;= _NtReadVirtualMemory@20
+    NtResetEvent                          ;;= _NtResetEvent@8
+    NtResumeProcess                       ;;= _NtResumeProcess@4
+    NtResumeThread                        ;;= _NtResumeThread@8
+    NtSetContextThread                    ;;= _NtSetContextThread@8
+    NtSetEvent                            ;;= _NtSetEvent@8
+    NtSetInformationFile                  ;;= _NtSetInformationFile@20
+    NtSetInformationObject                ;;= _NtSetInformationObject@16
+    NtSetInformationProcess               ;;= _NtSetInformationProcess@16
+    NtSetInformationThread                ;;= _NtSetInformationThread@16
+    NtSetTimerResolution                  ;;= _NtSetTimerResolution@12
+    NtSuspendProcess                      ;;= _NtSuspendProcess@4
+    NtSuspendThread                       ;;= _NtSuspendThread@8
+    NtTerminateProcess                    ;;= _NtTerminateProcess@8
+    NtTerminateThread                     ;;= _NtTerminateThread@8
+    NtUnmapViewOfSection                  ;;= _NtUnmapViewOfSection@8
+    NtWaitForMultipleObjects              ;;= _NtWaitForMultipleObjects@20
+    NtWaitForSingleObject                 ;;= _NtWaitForSingleObject@12
+    NtWriteFile                           ;;= _NtWriteFile@36
+    NtWriteVirtualMemory                  ;;= _NtWriteVirtualMemory@20
+    NtYieldExecution                      ;;= _NtYieldExecution@0
+
+    LdrInitializeThunk                    ;;= _LdrInitializeThunk@12
+    LdrRegisterDllNotification            ;;= _LdrRegisterDllNotification@16
+    LdrLoadDll                            ;;= _LdrLoadDll@16
+    LdrUnloadDll                          ;;= _LdrUnloadDll@4
+    LdrGetDllHandle                       ;;= _LdrGetDllHandle@16
+    LdrGetDllHandleEx                     ;;= _LdrGetDllHandleEx@20
+    LdrGetDllHandleByMapping              ;;= _LdrGetDllHandleByMapping@8
+    LdrGetDllHandleByName                 ;;= _LdrGetDllHandleByName@12
+    LdrAddRefDll                          ;;= _LdrAddRefDll@8
+    LdrGetProcedureAddress                ;;= _LdrGetProcedureAddress@12
+    LdrGetProcedureAddressEx              ;;= _LdrGetProcedureAddressEx@16
+    LdrLockLoaderLock                     ;;= _LdrLockLoaderLock@12
+    LdrUnlockLoaderLock                   ;;= _LdrUnlockLoaderLock@8
+
+    RtlAcquirePebLock                     ;;= _RtlAcquirePebLock@0
+    RtlAddAccessAllowedAce                ;;= _RtlAddAccessAllowedAce@16
+    RtlAddAccessDeniedAce                 ;;= _RtlAddAccessDeniedAce@16
+    RtlAllocateHeap                       ;;= _RtlAllocateHeap@12
+    RtlCompactHeap                        ;;= _RtlCompactHeap@8
+    RtlCopySid                            ;;= _RtlCopySid@12
+    RtlCreateAcl                          ;;= _RtlCreateAcl@12
+    RtlCreateHeap                         ;;= _RtlCreateHeap@24
+    RtlCreateProcessParameters            ;;= _RtlCreateProcessParameters@40
+    RtlCreateSecurityDescriptor           ;;= _RtlCreateSecurityDescriptor@8
+    RtlCreateUserProcess                  ;;= _RtlCreateUserProcess@40
+    RtlCreateUserThread                   ;;= _RtlCreateUserThread@40
+    RtlDestroyProcessParameters           ;;= _RtlDestroyProcessParameters@4
+    RtlDosApplyFileIsolationRedirection_Ustr ;;= _RtlDosApplyFileIsolationRedirection_Ustr@36
+    RtlEqualSid                           ;;= _RtlEqualSid@8
+    RtlExitUserProcess                    ;;= _RtlExitUserProcess@4
+    RtlExitUserThread                     ;;= _RtlExitUserThread@4
+    RtlExpandEnvironmentStrings_U         ;;= _RtlExpandEnvironmentStrings_U@16
+    RtlFreeHeap                           ;;= _RtlFreeHeap@12
+    RtlFreeUnicodeString                  ;;= _RtlFreeUnicodeString@4
+    RtlGetLastNtStatus                    ;;= _RtlGetLastNtStatus@0
+    RtlGetLastWin32Error                  ;;= _RtlGetLastWin32Error@0
+    RtlGetVersion                         ;;= _RtlGetVersion@4
+    RtlGetNtProductType                   ;;= _RtlGetNtProductType@4
+    RtlInitializeSid                      ;;= _RtlInitializeSid@12
+    RtlNtStatusToDosError                 ;;= _RtlNtStatusToDosError@4
+    RtlReAllocateHeap                     ;;= _RtlReAllocateHeap@16
+    RtlReleasePebLock                     ;;= _RtlReleasePebLock@0
+    RtlRestoreLastWin32Error              ;;= _RtlRestoreLastWin32Error@4
+    RtlSetDaclSecurityDescriptor          ;;= _RtlSetDaclSecurityDescriptor@16
+    RtlSetLastWin32Error                  ;;= _RtlSetLastWin32Error@4
+    RtlSetLastWin32ErrorAndNtStatusFromNtStatus ;;= _RtlSetLastWin32ErrorAndNtStatusFromNtStatus@4
+    RtlSizeHeap                           ;;= _RtlSizeHeap@12
+    RtlSubAuthoritySid                    ;;= _RtlSubAuthoritySid@8
+    RtlQueryPerformanceCounter            ;;= _RtlQueryPerformanceCounter@4
+    RtlGetSystemTimePrecise               ;;= _RtlGetSystemTimePrecise@0
+
diff --git a/src/VBox/Runtime/r3/win/path-win.cpp b/src/VBox/Runtime/r3/win/path-win.cpp
new file mode 100644
index 00000000..587de0f6
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/path-win.cpp
@@ -0,0 +1,743 @@
+/* $Id: path-win.cpp $ */
+/** @file
+ * IPRT - Path manipulation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PATH
+#include <iprt/win/windows.h>
+#include <iprt/win/shlobj.h>
+
+#include <iprt/path.h>
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include <iprt/utf16.h>
+#include "internal/path.h"
+#include "internal/fs.h"
+
+/* Needed for lazy loading SHGetFolderPathW in RTPathUserDocuments(). */
+typedef HRESULT WINAPI FNSHGETFOLDERPATHW(HWND, int, HANDLE, DWORD, LPWSTR);
+typedef FNSHGETFOLDERPATHW *PFNSHGETFOLDERPATHW;
+
+
+RTDECL(int) RTPathReal(const char *pszPath, char *pszRealPath, size_t cchRealPath)
+{
+    /*
+     * Convert to UTF-16, call Win32 APIs, convert back.
+     */
+    PRTUTF16 pwszPath;
+    int rc = RTPathWinFromUtf8(&pwszPath, pszPath, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        LPWSTR lpFile;
+        WCHAR  wsz[RTPATH_MAX];
+        rc = GetFullPathNameW((LPCWSTR)pwszPath, RT_ELEMENTS(wsz), &wsz[0], &lpFile);
+        if (rc > 0 && rc < RT_ELEMENTS(wsz))
+        {
+            /* Check that it exists. (Use RTPathAbs() to just resolve the name.) */
+            DWORD dwAttr = GetFileAttributesW(wsz);
+            if (dwAttr != INVALID_FILE_ATTRIBUTES)
+                rc = RTUtf16ToUtf8Ex((PRTUTF16)&wsz[0], RTSTR_MAX, &pszRealPath, cchRealPath, NULL);
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else if (rc <= 0)
+            rc = RTErrConvertFromWin32(GetLastError());
+        else
+            rc = VERR_FILENAME_TOO_LONG;
+
+        RTPathWinFree(pwszPath);
+    }
+    return rc;
+}
+
+#if 0
+RTDECL(int) RTPathAbs(const char *pszPath, char *pszAbsPath, size_t cchAbsPath)
+{
+    /*
+     * Validation.
+     */
+    AssertPtr(pszAbsPath);
+    AssertPtr(pszPath);
+    if (RT_UNLIKELY(!*pszPath))
+        return VERR_INVALID_PARAMETER;
+
+    /*
+     * Convert to UTF-16, call Win32 API, convert back.
+     */
+    LPWSTR pwszPath;
+    int rc = RTStrToUtf16(pszPath, &pwszPath);
+    if (!RT_SUCCESS(rc))
+        return (rc);
+
+    LPWSTR pwszFile; /* Ignored */
+    RTUTF16 wsz[RTPATH_MAX];
+    rc = GetFullPathNameW(pwszPath, RT_ELEMENTS(wsz), &wsz[0], &pwszFile);
+    if (rc > 0 && rc < RT_ELEMENTS(wsz))
+    {
+        size_t cch;
+        rc = RTUtf16ToUtf8Ex(&wsz[0], RTSTR_MAX, &pszAbsPath, cchAbsPath, &cch);
+        if (RT_SUCCESS(rc))
+        {
+# if 1 /** @todo This code is completely bonkers. */
+            /*
+             * Remove trailing slash if the path may be pointing to a directory.
+             * (See posix variant.)
+             */
+            if (    cch > 1
+                &&  RTPATH_IS_SLASH(pszAbsPath[cch - 1])
+                &&  !RTPATH_IS_VOLSEP(pszAbsPath[cch - 2])
+                &&  !RTPATH_IS_SLASH(pszAbsPath[cch - 2]))
+                pszAbsPath[cch - 1] = '\0';
+# endif
+        }
+    }
+    else if (rc <= 0)
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+        rc = VERR_FILENAME_TOO_LONG;
+
+    RTUtf16Free(pwszPath);
+    return rc;
+}
+#endif
+
+
+RTDECL(int) RTPathUserHome(char *pszPath, size_t cchPath)
+{
+    /*
+     * Validate input
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(cchPath, VERR_INVALID_PARAMETER);
+
+    RTUTF16 wszPath[RTPATH_MAX];
+    bool    fValidFolderPath = false;
+
+    /*
+     * Try with Windows XP+ functionality first.
+     */
+    RTLDRMOD hShell32;
+    int rc = RTLdrLoadSystem("Shell32.dll", true /*fNoUnload*/, &hShell32);
+    if (RT_SUCCESS(rc))
+    {
+        PFNSHGETFOLDERPATHW pfnSHGetFolderPathW;
+        rc = RTLdrGetSymbol(hShell32, "SHGetFolderPathW", (void**)&pfnSHGetFolderPathW);
+        if (RT_SUCCESS(rc))
+        {
+            HRESULT hrc = pfnSHGetFolderPathW(0, CSIDL_PROFILE, NULL, SHGFP_TYPE_CURRENT, wszPath);
+            fValidFolderPath = (hrc == S_OK);
+        }
+        RTLdrClose(hShell32);
+    }
+
+    DWORD   dwAttr;
+    if (    !fValidFolderPath
+        ||  (dwAttr = GetFileAttributesW(&wszPath[0])) == INVALID_FILE_ATTRIBUTES
+        ||  !(dwAttr & FILE_ATTRIBUTE_DIRECTORY))
+    {
+        /*
+         * Fall back to Windows specific environment variables. HOME is not used.
+         */
+        if (    !GetEnvironmentVariableW(L"USERPROFILE", &wszPath[0], RTPATH_MAX)
+            ||  (dwAttr = GetFileAttributesW(&wszPath[0])) == INVALID_FILE_ATTRIBUTES
+            ||  !(dwAttr & FILE_ATTRIBUTE_DIRECTORY))
+        {
+            /* %HOMEDRIVE%%HOMEPATH% */
+            if (!GetEnvironmentVariableW(L"HOMEDRIVE", &wszPath[0], RTPATH_MAX))
+                return VERR_PATH_NOT_FOUND;
+            size_t const cwc = RTUtf16Len(&wszPath[0]);
+            if (    !GetEnvironmentVariableW(L"HOMEPATH", &wszPath[cwc], RTPATH_MAX - (DWORD)cwc)
+                ||  (dwAttr = GetFileAttributesW(&wszPath[0])) == INVALID_FILE_ATTRIBUTES
+                ||  !(dwAttr & FILE_ATTRIBUTE_DIRECTORY))
+                return VERR_PATH_NOT_FOUND;
+        }
+    }
+
+    /*
+     * Convert and return.
+     */
+    return RTUtf16ToUtf8Ex(&wszPath[0], RTSTR_MAX, &pszPath, cchPath, NULL);
+}
+
+
+RTDECL(int) RTPathUserDocuments(char *pszPath, size_t cchPath)
+{
+    /*
+     * Validate input
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(cchPath, VERR_INVALID_PARAMETER);
+
+    RTLDRMOD hShell32;
+    int rc = RTLdrLoadSystem("Shell32.dll", true /*fNoUnload*/, &hShell32);
+    if (RT_SUCCESS(rc))
+    {
+        PFNSHGETFOLDERPATHW pfnSHGetFolderPathW;
+        rc = RTLdrGetSymbol(hShell32, "SHGetFolderPathW", (void**)&pfnSHGetFolderPathW);
+        if (RT_SUCCESS(rc))
+        {
+            RTUTF16 wszPath[RTPATH_MAX];
+            HRESULT hrc = pfnSHGetFolderPathW(0, CSIDL_PERSONAL, NULL, SHGFP_TYPE_CURRENT, wszPath);
+            if (   hrc == S_OK     /* Found */
+                || hrc == S_FALSE) /* Found, but doesn't exist */
+            {
+                /*
+                 * Convert and return.
+                 */
+                RTLdrClose(hShell32);
+                return RTUtf16ToUtf8Ex(&wszPath[0], RTSTR_MAX, &pszPath, cchPath, NULL);
+            }
+        }
+        RTLdrClose(hShell32);
+    }
+    return VERR_PATH_NOT_FOUND;
+}
+
+
+#if 0 /* use nt version of this */
+
+RTR3DECL(int) RTPathQueryInfo(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs)
+{
+    return RTPathQueryInfoEx(pszPath, pObjInfo, enmAdditionalAttribs, RTPATH_F_ON_LINK);
+}
+#endif
+#if 0
+
+
+RTR3DECL(int) RTPathQueryInfoEx(const char *pszPath, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pObjInfo, VERR_INVALID_POINTER);
+    AssertMsgReturn(    enmAdditionalAttribs >= RTFSOBJATTRADD_NOTHING
+                    &&  enmAdditionalAttribs <= RTFSOBJATTRADD_LAST,
+                    ("Invalid enmAdditionalAttribs=%p\n", enmAdditionalAttribs),
+                    VERR_INVALID_PARAMETER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Query file info.
+     */
+    uint32_t uReparseTag = RTFSMODE_SYMLINK_REPARSE_TAG;
+    WIN32_FILE_ATTRIBUTE_DATA Data;
+    PRTUTF16 pwszPath;
+    int rc = RTStrToUtf16(pszPath, &pwszPath);
+    if (RT_FAILURE(rc))
+        return rc;
+    if (!GetFileAttributesExW(pwszPath, GetFileExInfoStandard, &Data))
+    {
+        /* Fallback to FindFileFirst in case of sharing violation. */
+        if (GetLastError() == ERROR_SHARING_VIOLATION)
+        {
+            WIN32_FIND_DATAW FindData;
+            HANDLE hDir = FindFirstFileW(pwszPath, &FindData);
+            if (hDir == INVALID_HANDLE_VALUE)
+            {
+                rc = RTErrConvertFromWin32(GetLastError());
+                RTUtf16Free(pwszPath);
+                return rc;
+            }
+            FindClose(hDir);
+
+            Data.dwFileAttributes   = FindData.dwFileAttributes;
+            Data.ftCreationTime     = FindData.ftCreationTime;
+            Data.ftLastAccessTime   = FindData.ftLastAccessTime;
+            Data.ftLastWriteTime    = FindData.ftLastWriteTime;
+            Data.nFileSizeHigh      = FindData.nFileSizeHigh;
+            Data.nFileSizeLow       = FindData.nFileSizeLow;
+            uReparseTag             = FindData.dwReserved0;
+        }
+        else
+        {
+            rc = RTErrConvertFromWin32(GetLastError());
+            RTUtf16Free(pwszPath);
+            return rc;
+        }
+    }
+
+    /*
+     * Getting the information for the link target is a bit annoying and
+     * subject to the same access violation mess as above.. :/
+     */
+    /** @todo we're too lazy wrt to error paths here... */
+    if (   (Data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
+        && ((fFlags & RTPATH_F_FOLLOW_LINK) || uReparseTag != RTFSMODE_SYMLINK_REPARSE_TAG))
+    {
+        HANDLE hFinal = CreateFileW(pwszPath,
+                                    GENERIC_READ,
+                                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                    NULL,
+                                    OPEN_EXISTING,
+                                    FILE_FLAG_BACKUP_SEMANTICS,
+                                    NULL);
+        if (hFinal != INVALID_HANDLE_VALUE)
+        {
+            BY_HANDLE_FILE_INFORMATION FileData;
+            if (GetFileInformationByHandle(hFinal, &FileData))
+            {
+                Data.dwFileAttributes   = FileData.dwFileAttributes;
+                Data.ftCreationTime     = FileData.ftCreationTime;
+                Data.ftLastAccessTime   = FileData.ftLastAccessTime;
+                Data.ftLastWriteTime    = FileData.ftLastWriteTime;
+                Data.nFileSizeHigh      = FileData.nFileSizeHigh;
+                Data.nFileSizeLow       = FileData.nFileSizeLow;
+                uReparseTag             = 0;
+            }
+            CloseHandle(hFinal);
+        }
+        else if (GetLastError() != ERROR_SHARING_VIOLATION)
+        {
+            rc = RTErrConvertFromWin32(GetLastError());
+            RTUtf16Free(pwszPath);
+            return rc;
+        }
+    }
+
+    RTUtf16Free(pwszPath);
+
+    /*
+     * Setup the returned data.
+     */
+    pObjInfo->cbObject    = ((uint64_t)Data.nFileSizeHigh << 32)
+                          |  (uint64_t)Data.nFileSizeLow;
+    pObjInfo->cbAllocated = pObjInfo->cbObject;
+
+    Assert(sizeof(uint64_t) == sizeof(Data.ftCreationTime));
+    RTTimeSpecSetNtTime(&pObjInfo->BirthTime,         *(uint64_t *)&Data.ftCreationTime);
+    RTTimeSpecSetNtTime(&pObjInfo->AccessTime,        *(uint64_t *)&Data.ftLastAccessTime);
+    RTTimeSpecSetNtTime(&pObjInfo->ModificationTime,  *(uint64_t *)&Data.ftLastWriteTime);
+    pObjInfo->ChangeTime  = pObjInfo->ModificationTime;
+
+    pObjInfo->Attr.fMode  = rtFsModeFromDos((Data.dwFileAttributes << RTFS_DOS_SHIFT) & RTFS_DOS_MASK_NT,
+                                            pszPath, strlen(pszPath), uReparseTag);
+
+    /*
+     * Requested attributes (we cannot provide anything actually).
+     */
+    switch (enmAdditionalAttribs)
+    {
+        case RTFSOBJATTRADD_NOTHING:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_NOTHING;
+            break;
+
+        case RTFSOBJATTRADD_UNIX:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX;
+            pObjInfo->Attr.u.Unix.uid             = ~0U;
+            pObjInfo->Attr.u.Unix.gid             = ~0U;
+            pObjInfo->Attr.u.Unix.cHardlinks      = 1;
+            pObjInfo->Attr.u.Unix.INodeIdDevice   = 0; /** @todo use volume serial number */
+            pObjInfo->Attr.u.Unix.INodeId         = 0; /** @todo use fileid (see GetFileInformationByHandle). */
+            pObjInfo->Attr.u.Unix.fFlags          = 0;
+            pObjInfo->Attr.u.Unix.GenerationId    = 0;
+            pObjInfo->Attr.u.Unix.Device          = 0;
+            break;
+
+        case RTFSOBJATTRADD_UNIX_OWNER:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_OWNER;
+            pObjInfo->Attr.u.UnixOwner.uid        = ~0U;
+            pObjInfo->Attr.u.UnixOwner.szName[0]  = '\0'; /** @todo return something sensible here. */
+            break;
+
+        case RTFSOBJATTRADD_UNIX_GROUP:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_UNIX_GROUP;
+            pObjInfo->Attr.u.UnixGroup.gid        = ~0U;
+            pObjInfo->Attr.u.UnixGroup.szName[0]  = '\0';
+            break;
+
+        case RTFSOBJATTRADD_EASIZE:
+            pObjInfo->Attr.enmAdditional          = RTFSOBJATTRADD_EASIZE;
+            pObjInfo->Attr.u.EASize.cb            = 0;
+            break;
+
+        default:
+            AssertMsgFailed(("Impossible!\n"));
+            return VERR_INTERNAL_ERROR;
+    }
+
+    return VINF_SUCCESS;
+}
+
+#endif /* using NT version*/
+
+
+RTR3DECL(int) RTPathSetTimes(const char *pszPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                             PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
+{
+    return RTPathSetTimesEx(pszPath, pAccessTime, pModificationTime, pChangeTime, pBirthTime, RTPATH_F_ON_LINK);
+}
+
+
+RTR3DECL(int) RTPathSetTimesEx(const char *pszPath, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+                               PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pAccessTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pModificationTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pChangeTime, VERR_INVALID_POINTER);
+    AssertPtrNullReturn(pBirthTime, VERR_INVALID_POINTER);
+    AssertMsgReturn(RTPATH_F_IS_VALID(fFlags, 0), ("%#x\n", fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the path.
+     */
+    PRTUTF16 pwszPath;
+    int rc = RTPathWinFromUtf8(&pwszPath, pszPath, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE hFile;
+        if (fFlags & RTPATH_F_FOLLOW_LINK)
+            hFile = CreateFileW(pwszPath,
+                                FILE_WRITE_ATTRIBUTES,   /* dwDesiredAccess */
+                                FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE, /* dwShareMode */
+                                NULL,                    /* security attribs */
+                                OPEN_EXISTING,           /* dwCreationDisposition */
+                                FILE_FLAG_BACKUP_SEMANTICS | FILE_ATTRIBUTE_NORMAL,
+                                NULL);
+        else
+        {
+/** @todo Symlink: Test RTPathSetTimesEx on Windows. (The code is disabled
+ *        because it's not tested yet.) */
+#if 0 //def FILE_FLAG_OPEN_REPARSE_POINT
+            hFile = CreateFileW(pwszPath,
+                                FILE_WRITE_ATTRIBUTES,   /* dwDesiredAccess */
+                                FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE, /* dwShareMode */
+                                NULL,                    /* security attribs */
+                                OPEN_EXISTING,           /* dwCreationDisposition */
+                                FILE_FLAG_BACKUP_SEMANTICS | FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OPEN_REPARSE_POINT,
+                                NULL);
+
+            if (hFile == INVALID_HANDLE_VALUE && GetLastError() == ERROR_INVALID_PARAMETER)
+#endif
+                hFile = CreateFileW(pwszPath,
+                                    FILE_WRITE_ATTRIBUTES,   /* dwDesiredAccess */
+                                    FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE, /* dwShareMode */
+                                    NULL,                    /* security attribs */
+                                    OPEN_EXISTING,           /* dwCreationDisposition */
+                                    FILE_FLAG_BACKUP_SEMANTICS | FILE_ATTRIBUTE_NORMAL,
+                                    NULL);
+        }
+        if (hFile != INVALID_HANDLE_VALUE)
+        {
+            /*
+             * Check if it's a no-op.
+             */
+            if (!pAccessTime && !pModificationTime && !pBirthTime)
+                rc = VINF_SUCCESS;    /* NOP */
+            else
+            {
+                /*
+                 * Convert the input and call the API.
+                 */
+                FILETIME    CreationTimeFT;
+                PFILETIME   pCreationTimeFT = NULL;
+                if (pBirthTime)
+                    pCreationTimeFT = RTTimeSpecGetNtFileTime(pBirthTime, &CreationTimeFT);
+
+                FILETIME    LastAccessTimeFT;
+                PFILETIME   pLastAccessTimeFT = NULL;
+                if (pAccessTime)
+                    pLastAccessTimeFT = RTTimeSpecGetNtFileTime(pAccessTime, &LastAccessTimeFT);
+
+                FILETIME    LastWriteTimeFT;
+                PFILETIME   pLastWriteTimeFT = NULL;
+                if (pModificationTime)
+                    pLastWriteTimeFT = RTTimeSpecGetNtFileTime(pModificationTime, &LastWriteTimeFT);
+
+                if (SetFileTime(hFile, pCreationTimeFT, pLastAccessTimeFT, pLastWriteTimeFT))
+                    rc = VINF_SUCCESS;
+                else
+                {
+                    DWORD Err = GetLastError();
+                    rc = RTErrConvertFromWin32(Err);
+                    Log(("RTPathSetTimes('%s', %p, %p, %p, %p): SetFileTime failed with lasterr %d (%Rrc)\n",
+                         pszPath, pAccessTime, pModificationTime, pChangeTime, pBirthTime, Err, rc));
+                }
+            }
+            BOOL fRc = CloseHandle(hFile); Assert(fRc); NOREF(fRc);
+        }
+        else
+        {
+            DWORD Err = GetLastError();
+            rc = RTErrConvertFromWin32(Err);
+            Log(("RTPathSetTimes('%s',,,,): failed with %Rrc and lasterr=%u\n", pszPath, rc, Err));
+        }
+
+        RTPathWinFree(pwszPath);
+    }
+
+    LogFlow(("RTPathSetTimes(%p:{%s}, %p:{%RDtimespec}, %p:{%RDtimespec}, %p:{%RDtimespec}, %p:{%RDtimespec}): return %Rrc\n",
+             pszPath, pszPath, pAccessTime, pAccessTime, pModificationTime, pModificationTime,
+             pChangeTime, pChangeTime, pBirthTime, pBirthTime));
+    return rc;
+}
+
+
+
+
+/**
+ * Internal worker for RTFileRename and RTFileMove.
+ *
+ * @returns iprt status code.
+ * @param   pszSrc      The source filename.
+ * @param   pszDst      The destination filename.
+ * @param   fFlags      The windows MoveFileEx flags.
+ * @param   fFileType   The filetype. We use the RTFMODE filetypes here. If it's 0,
+ *                      anything goes. If it's RTFS_TYPE_DIRECTORY we'll check that the
+ *                      source is a directory. If Its RTFS_TYPE_FILE we'll check that it's
+ *                      not a directory (we are NOT checking whether it's a file).
+ */
+DECLHIDDEN(int) rtPathWin32MoveRename(const char *pszSrc, const char *pszDst, uint32_t fFlags, RTFMODE fFileType)
+{
+    /*
+     * Convert the strings.
+     */
+    PRTUTF16 pwszSrc;
+    int rc = RTPathWinFromUtf8(&pwszSrc, pszSrc, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        PRTUTF16 pwszDst;
+        rc = RTPathWinFromUtf8(&pwszDst, pszDst, 0 /*fFlags*/);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Check object type if requested.
+             * This is open to race conditions.
+             */
+            if (fFileType)
+            {
+                DWORD dwAttr = GetFileAttributesW(pwszSrc);
+                if (dwAttr == INVALID_FILE_ATTRIBUTES)
+                    rc = RTErrConvertFromWin32(GetLastError());
+                else if (RTFS_IS_DIRECTORY(fFileType))
+                    rc = dwAttr & FILE_ATTRIBUTE_DIRECTORY ? VINF_SUCCESS : VERR_NOT_A_DIRECTORY;
+                else
+                    rc = dwAttr & FILE_ATTRIBUTE_DIRECTORY ? VERR_IS_A_DIRECTORY : VINF_SUCCESS;
+            }
+            if (RT_SUCCESS(rc))
+            {
+                if (MoveFileExW(pwszSrc, pwszDst, fFlags))
+                    rc = VINF_SUCCESS;
+                else
+                {
+                    DWORD Err = GetLastError();
+                    rc = RTErrConvertFromWin32(Err);
+                    Log(("MoveFileExW('%s', '%s', %#x, %RTfmode): fails with rc=%Rrc & lasterr=%d\n",
+                         pszSrc, pszDst, fFlags, fFileType, rc, Err));
+                }
+            }
+            RTPathWinFree(pwszDst);
+        }
+        RTPathWinFree(pwszSrc);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathRename(const char *pszSrc, const char *pszDst, unsigned fRename)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszSrc, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDst, VERR_INVALID_POINTER);
+    AssertMsgReturn(*pszSrc, ("%p\n", pszSrc), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(*pszDst, ("%p\n", pszDst), VERR_INVALID_PARAMETER);
+    AssertMsgReturn(!(fRename & ~RTPATHRENAME_FLAGS_REPLACE), ("%#x\n", fRename), VERR_INVALID_PARAMETER);
+
+    /*
+     * Call the worker.
+     */
+    int rc = rtPathWin32MoveRename(pszSrc, pszDst, fRename & RTPATHRENAME_FLAGS_REPLACE ? MOVEFILE_REPLACE_EXISTING : 0, 0);
+
+    LogFlow(("RTPathRename(%p:{%s}, %p:{%s}, %#x): returns %Rrc\n", pszSrc, pszSrc, pszDst, pszDst, fRename, rc));
+    return rc;
+}
+
+
+RTR3DECL(int) RTPathUnlink(const char *pszPath, uint32_t fUnlink)
+{
+    RT_NOREF_PV(pszPath); RT_NOREF_PV(fUnlink);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(bool) RTPathExists(const char *pszPath)
+{
+    return RTPathExistsEx(pszPath, RTPATH_F_FOLLOW_LINK);
+}
+
+
+RTDECL(bool) RTPathExistsEx(const char *pszPath, uint32_t fFlags)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, false);
+    AssertReturn(*pszPath, false);
+    Assert(RTPATH_F_IS_VALID(fFlags, 0));
+
+    /*
+     * Try query file info.
+     */
+    DWORD dwAttr;
+    PRTUTF16 pwszPath;
+    int rc = RTPathWinFromUtf8(&pwszPath, pszPath, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        dwAttr = GetFileAttributesW(pwszPath);
+        RTPathWinFree(pwszPath);
+    }
+    else
+        dwAttr = INVALID_FILE_ATTRIBUTES;
+    if (dwAttr == INVALID_FILE_ATTRIBUTES)
+        return false;
+
+#ifdef FILE_ATTRIBUTE_REPARSE_POINT
+    if (   (fFlags & RTPATH_F_FOLLOW_LINK)
+        && (dwAttr & FILE_ATTRIBUTE_REPARSE_POINT))
+    {
+        AssertFailed();
+        /** @todo Symlinks: RTPathExists+RTPathExistsEx is misbehaving on symbolic
+         *        links on Windows. */
+    }
+#endif
+
+    return true;
+}
+
+
+RTDECL(int) RTPathGetCurrent(char *pszPath, size_t cchPath)
+{
+    int rc;
+
+    if (cchPath > 0)
+    {
+        /*
+         * GetCurrentDirectory may in some cases omit the drive letter, according
+         * to MSDN, thus the GetFullPathName call.
+         */
+        RTUTF16 wszCurPath[RTPATH_MAX];
+        if (GetCurrentDirectoryW(RTPATH_MAX, wszCurPath))
+        {
+            RTUTF16 wszFullPath[RTPATH_MAX];
+            if (GetFullPathNameW(wszCurPath, RTPATH_MAX, wszFullPath, NULL))
+            {
+                if (   wszFullPath[1] == ':'
+                    && RT_C_IS_LOWER(wszFullPath[0]))
+                    wszFullPath[0] = RT_C_TO_UPPER(wszFullPath[0]);
+
+                rc = RTUtf16ToUtf8Ex(&wszFullPath[0], RTSTR_MAX, &pszPath, cchPath, NULL);
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+        rc = VERR_BUFFER_OVERFLOW;
+    return rc;
+}
+
+
+RTDECL(int) RTPathSetCurrent(const char *pszPath)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pszPath, VERR_INVALID_POINTER);
+    AssertReturn(*pszPath, VERR_INVALID_PARAMETER);
+
+    /*
+     * This interface is almost identical to the Windows API.
+     */
+    PRTUTF16 pwszPath;
+    int rc = RTPathWinFromUtf8(&pwszPath, pszPath, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        /** @todo improve the slash stripping a bit? */
+        size_t cwc = RTUtf16Len(pwszPath);
+        if (    cwc >= 2
+            &&  (   pwszPath[cwc - 1] == L'/'
+                 || pwszPath[cwc - 1] == L'\\')
+            &&  pwszPath[cwc - 2] != ':')
+            pwszPath[cwc - 1] = L'\0';
+
+        if (!SetCurrentDirectoryW(pwszPath))
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        RTPathWinFree(pwszPath);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPathGetCurrentOnDrive(char chDrive, char *pszPath, size_t cbPath)
+{
+    int rc;
+    if (cbPath > 0)
+    {
+        WCHAR wszInput[4];
+        wszInput[0] = chDrive;
+        wszInput[1] = ':';
+        wszInput[2] = '\0';
+        RTUTF16 wszFullPath[RTPATH_MAX];
+        if (GetFullPathNameW(wszInput, RTPATH_MAX, wszFullPath, NULL))
+            rc = RTUtf16ToUtf8Ex(&wszFullPath[0], RTSTR_MAX, &pszPath, cbPath, NULL);
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+        rc = VERR_BUFFER_OVERFLOW;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/pathint-win.cpp b/src/VBox/Runtime/r3/win/pathint-win.cpp
new file mode 100644
index 00000000..81799cc5
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/pathint-win.cpp
@@ -0,0 +1,204 @@
+/* $Id: pathint-win.cpp $ */
+/** @file
+ * IPRT - Windows, Internal Path stuff.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_FS
+#include <iprt/path.h>
+
+#include <iprt/assert.h>
+#include <iprt/ctype.h>
+#include <iprt/errcore.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+
+#include <iprt/nt/nt-and-windows.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The max number of non-null characters we pass to an Win32 API.
+ * You would think that MAX_PATH gives this length, however CreateDirectoryW was
+ * found to fail on Windows 10 (1803++) if given a perfectly formed path argument
+ * of 248 or more characters.  Same when going thru UNC.
+ *
+ * So, to be conservative, we put the max number of characters in a non-\\?\
+ * path to 243, not counting the terminator.
+ */
+#define ACTUAL_MAX_PATH     243
+
+
+DECL_NO_INLINE(static, bool) rtPathWinTryConvertToAbs(PRTUTF16 *ppwszPath)
+{
+    RTUTF16 wszFullPath[MAX_PATH + 1];
+    DWORD cwcFull = GetFullPathNameW(*ppwszPath, MAX_PATH + 1, wszFullPath, NULL);
+    if (cwcFull <= ACTUAL_MAX_PATH)
+    {
+        RTUtf16Free(*ppwszPath);
+        PRTUTF16 const pwszCopy = RTUtf16Dup(wszFullPath);
+        *ppwszPath = pwszCopy;
+        if (pwszCopy)
+            return true;
+    }
+    return false;
+}
+
+
+RTDECL(int)  RTPathWinFromUtf8(PRTUTF16 *ppwszPath, const char *pszPath, uint32_t fFlags)
+{
+    Assert(fFlags == 0);
+    RT_NOREF(fFlags);
+
+    /*
+     * Do a straight conversion first.
+     */
+    *ppwszPath = NULL;
+    size_t cwcResult = 0;
+    int rc = RTStrToUtf16Ex(pszPath, RTSTR_MAX, ppwszPath, 0, &cwcResult);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Check the resulting length.  This is straight forward for absolute
+         * paths, but gets complicated for relative ones.
+         */
+        if (cwcResult <= ACTUAL_MAX_PATH)
+        {
+            if (RT_C_IS_ALPHA(pszPath[0]) && pszPath[1] == ':')
+            {
+                if (RTPATH_IS_SLASH(pszPath[2]))
+                    return VINF_SUCCESS;
+
+                /* Drive relative path.  Found no simple way of getting the current
+                   path of a drive, so we try convert it to an absolute path and see
+                   how that works out.  It is what the API we're calling will have to
+                   do anyway, so this should perform just as well. */
+                if (rtPathWinTryConvertToAbs(ppwszPath))
+                    return VINF_SUCCESS;
+            }
+            else if (RTPATH_IS_SLASH(pszPath[0]))
+            {
+                if (   RTPATH_IS_SLASH(pszPath[1])
+                    && !RTPATH_IS_SLASH(pszPath[2])
+                    && pszPath[2] != '\0')
+                {
+                    /* Passthru prefix '\\?\' is fine. */
+                    if (   pszPath[2] == '?'
+                        && !RTPATH_IS_SLASH(pszPath[3]))
+                        return VINF_SUCCESS;
+
+                    /* UNC requires a longer prefix ('\??\UNC\' instead of '\??\'), so
+                       subtract 3 chars from the max limit to be on the safe side.  */
+                    if (cwcResult <= ACTUAL_MAX_PATH - 3)
+                        return VINF_SUCCESS;
+                }
+                else
+                {
+                    /* Drive relative. Win32 will prepend a two letter drive specification. */
+                    if (cwcResult <= ACTUAL_MAX_PATH - 2)
+                        return VINF_SUCCESS;
+                }
+            }
+            else
+            {
+                /* Relative to CWD.  We can use the API to get it's current length.
+                   Any race conditions here is entirely  the caller's problem. */
+                size_t cwcCwd = GetCurrentDirectoryW(0, NULL);
+                if (cwcCwd + cwcResult <= ACTUAL_MAX_PATH - 1)
+                    return VINF_SUCCESS;
+            }
+        }
+        /*
+         * We're good if the caller already supplied the passthru/length prefix: '\\?\'
+         */
+        else if (   pszPath[1] == '?'
+                 && RTPATH_IS_SLASH(pszPath[3])
+                 && RTPATH_IS_SLASH(pszPath[1])
+                 && RTPATH_IS_SLASH(pszPath[0]))
+                 return VINF_SUCCESS;
+
+        /*
+         * Long path requiring \\?\ prefixing.
+         *
+         * We piggy back on the NT conversion here and ASSUME RTUtf16Free is the right
+         * way to free the result.
+         */
+        RTUtf16Free(*ppwszPath);
+        *ppwszPath = NULL;
+
+        struct _UNICODE_STRING  NtName   = { 0, 0, NULL };
+        HANDLE                  hRootDir = NULL;
+        rc = RTNtPathFromWinUtf8(&NtName, &hRootDir, pszPath);
+        if (RT_SUCCESS(rc))
+        {
+            /* No root dir handle. */
+            if (hRootDir == NULL)
+            {
+                /* Convert the NT '\??\' prefix to a win32 passthru prefix '\\?\' */
+                if (   NtName.Buffer[0] == '\\'
+                    && NtName.Buffer[1] == '?'
+                    && NtName.Buffer[2] == '?'
+                    && NtName.Buffer[3] == '\\')
+                {
+                    NtName.Buffer[1] = '\\';
+
+                    /* Zero termination paranoia. */
+                    if (NtName.Buffer[NtName.Length / sizeof(RTUTF16)] == '\0')
+                    {
+                        *ppwszPath = NtName.Buffer;
+                        return VINF_SUCCESS;
+                    }
+                    AssertMsgFailed(("Length=%u %.*ls\n", NtName.Length, NtName.Length / sizeof(RTUTF16), NtName.Buffer));
+                }
+                else
+                    AssertMsgFailed(("%ls\n", NtName.Buffer));
+            }
+            else
+                AssertMsgFailed(("%s\n", pszPath));
+            RTNtPathFree(&NtName, &hRootDir);
+        }
+    }
+    return rc;
+}
+
+
+RTDECL(void) RTPathWinFree(PRTUTF16 pwszPath)
+{
+    RTUtf16Free(pwszPath);
+}
+
diff --git a/src/VBox/Runtime/r3/win/pipe-win.cpp b/src/VBox/Runtime/r3/win/pipe-win.cpp
new file mode 100644
index 00000000..93bf9afc
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/pipe-win.cpp
@@ -0,0 +1,1537 @@
+/* $Id: pipe-win.cpp $ */
+/** @file
+ * IPRT - Anonymous Pipes, Windows Implementation.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/pipe.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/poll.h>
+#include <iprt/process.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/pipe.h"
+#include "internal/magics.h"
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The pipe buffer size we prefer. */
+#define RTPIPE_NT_SIZE      _64K
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct RTPIPEINTERNAL
+{
+    /** Magic value (RTPIPE_MAGIC). */
+    uint32_t            u32Magic;
+    /** The pipe handle. */
+    HANDLE              hPipe;
+    /** Set if this is the read end, clear if it's the write end. */
+    bool                fRead;
+    /** RTPipeFromNative: Leave native handle open on RTPipeClose. */
+    bool                fLeaveOpen;
+    /** Set if there is already pending I/O. */
+    bool                fIOPending;
+    /** Set if the zero byte read that the poll code using is pending. */
+    bool                fZeroByteRead;
+    /** Set if the pipe is broken. */
+    bool                fBrokenPipe;
+    /** Set if we've promised that the handle is writable. */
+    bool                fPromisedWritable;
+    /** Set if created inheritable. */
+    bool                fCreatedInheritable;
+    /** Usage counter. */
+    uint32_t            cUsers;
+    /** The overlapped I/O structure we use. */
+    OVERLAPPED          Overlapped;
+    /** Bounce buffer for writes. */
+    uint8_t            *pbBounceBuf;
+    /** Amount of used buffer space. */
+    size_t              cbBounceBufUsed;
+    /** Amount of allocated buffer space. */
+    size_t              cbBounceBufAlloc;
+    /** The handle of the poll set currently polling on this pipe.
+     *  We can only have one poller at the time (lazy bird). */
+    RTPOLLSET           hPollSet;
+    /** Critical section protecting the above members.
+     * (Taking the lazy/simple approach.) */
+    RTCRITSECT          CritSect;
+    /** Buffer for the zero byte read. */
+    uint8_t             abBuf[8];
+} RTPIPEINTERNAL;
+
+
+
+/**
+ * Wrapper for getting FILE_PIPE_LOCAL_INFORMATION via the NT API.
+ *
+ * @returns Success indicator (true/false).
+ * @param   pThis               The pipe.
+ * @param   pInfo               The info structure.
+ */
+static bool rtPipeQueryNtInfo(RTPIPEINTERNAL *pThis, FILE_PIPE_LOCAL_INFORMATION *pInfo)
+{
+    IO_STATUS_BLOCK Ios;
+    RT_ZERO(Ios);
+    RT_ZERO(*pInfo);
+    NTSTATUS rcNt = NtQueryInformationFile(pThis->hPipe, &Ios, pInfo, sizeof(*pInfo), FilePipeLocalInformation);
+    return rcNt >= 0;
+}
+
+
+RTDECL(int)  RTPipeCreate(PRTPIPE phPipeRead, PRTPIPE phPipeWrite, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipeRead, VERR_INVALID_POINTER);
+    AssertPtrReturn(phPipeWrite, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_C_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /*
+     * Create the read end of the pipe.
+     */
+    DWORD   dwErr;
+    HANDLE  hPipeR;
+    HANDLE  hPipeW;
+    int     rc;
+    for (;;)
+    {
+        static volatile uint32_t    g_iNextPipe = 0;
+        char                        szName[128];
+        RTStrPrintf(szName, sizeof(szName), "\\\\.\\pipe\\iprt-pipe-%u-%u", RTProcSelf(), ASMAtomicIncU32(&g_iNextPipe));
+
+        SECURITY_ATTRIBUTES  SecurityAttributes;
+        PSECURITY_ATTRIBUTES pSecurityAttributes = NULL;
+        if (fFlags & RTPIPE_C_INHERIT_READ)
+        {
+            SecurityAttributes.nLength              = sizeof(SecurityAttributes);
+            SecurityAttributes.lpSecurityDescriptor = NULL;
+            SecurityAttributes.bInheritHandle       = TRUE;
+            pSecurityAttributes = &SecurityAttributes;
+        }
+
+        DWORD dwOpenMode = PIPE_ACCESS_INBOUND | FILE_FLAG_OVERLAPPED;
+#ifdef FILE_FLAG_FIRST_PIPE_INSTANCE
+        dwOpenMode |= FILE_FLAG_FIRST_PIPE_INSTANCE;
+#endif
+
+        DWORD dwPipeMode = PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT;
+#ifdef PIPE_REJECT_REMOTE_CLIENTS
+        dwPipeMode |= PIPE_REJECT_REMOTE_CLIENTS;
+#endif
+
+        hPipeR = CreateNamedPipeA(szName, dwOpenMode, dwPipeMode, 1 /*nMaxInstances*/, RTPIPE_NT_SIZE, RTPIPE_NT_SIZE,
+                                  NMPWAIT_USE_DEFAULT_WAIT, pSecurityAttributes);
+#ifdef PIPE_REJECT_REMOTE_CLIENTS
+        if (hPipeR == INVALID_HANDLE_VALUE && GetLastError() == ERROR_INVALID_PARAMETER)
+        {
+            dwPipeMode &= ~PIPE_REJECT_REMOTE_CLIENTS;
+            hPipeR = CreateNamedPipeA(szName, dwOpenMode, dwPipeMode, 1 /*nMaxInstances*/, RTPIPE_NT_SIZE, RTPIPE_NT_SIZE,
+                                      NMPWAIT_USE_DEFAULT_WAIT, pSecurityAttributes);
+        }
+#endif
+#ifdef FILE_FLAG_FIRST_PIPE_INSTANCE
+        if (hPipeR == INVALID_HANDLE_VALUE && GetLastError() == ERROR_INVALID_PARAMETER)
+        {
+            dwOpenMode &= ~FILE_FLAG_FIRST_PIPE_INSTANCE;
+            hPipeR = CreateNamedPipeA(szName, dwOpenMode, dwPipeMode, 1 /*nMaxInstances*/, RTPIPE_NT_SIZE, RTPIPE_NT_SIZE,
+                                      NMPWAIT_USE_DEFAULT_WAIT, pSecurityAttributes);
+        }
+#endif
+        if (hPipeR != INVALID_HANDLE_VALUE)
+        {
+            /*
+             * Connect to the pipe (the write end).
+             * We add FILE_READ_ATTRIBUTES here to make sure we can query the
+             * pipe state later on.
+             */
+            pSecurityAttributes = NULL;
+            if (fFlags & RTPIPE_C_INHERIT_WRITE)
+            {
+                SecurityAttributes.nLength              = sizeof(SecurityAttributes);
+                SecurityAttributes.lpSecurityDescriptor = NULL;
+                SecurityAttributes.bInheritHandle       = TRUE;
+                pSecurityAttributes = &SecurityAttributes;
+            }
+
+            hPipeW = CreateFileA(szName,
+                                 GENERIC_WRITE | FILE_READ_ATTRIBUTES /*dwDesiredAccess*/,
+                                 0 /*dwShareMode*/,
+                                 pSecurityAttributes,
+                                 OPEN_EXISTING /* dwCreationDisposition */,
+                                 FILE_FLAG_OVERLAPPED /*dwFlagsAndAttributes*/,
+                                 NULL /*hTemplateFile*/);
+            if (hPipeW != INVALID_HANDLE_VALUE)
+                break;
+            dwErr = GetLastError();
+            CloseHandle(hPipeR);
+        }
+        else
+            dwErr = GetLastError();
+        if (   dwErr != ERROR_PIPE_BUSY     /* already exist - compatible */
+            && dwErr != ERROR_ACCESS_DENIED /* already exist - incompatible */)
+            return RTErrConvertFromWin32(dwErr);
+        /* else: try again with a new name */
+    }
+
+    /*
+     * Create the two handles.
+     */
+    RTPIPEINTERNAL *pThisR = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+    if (pThisR)
+    {
+        RTPIPEINTERNAL *pThisW = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+        if (pThisW)
+        {
+            rc = RTCritSectInit(&pThisR->CritSect);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTCritSectInit(&pThisW->CritSect);
+                if (RT_SUCCESS(rc))
+                {
+                    pThisR->Overlapped.hEvent = CreateEvent(NULL, TRUE /*fManualReset*/,
+                                                            TRUE /*fInitialState*/, NULL /*pName*/);
+                    if (pThisR->Overlapped.hEvent != NULL)
+                    {
+                        pThisW->Overlapped.hEvent = CreateEvent(NULL, TRUE /*fManualReset*/,
+                                                                TRUE /*fInitialState*/, NULL /*pName*/);
+                        if (pThisW->Overlapped.hEvent != NULL)
+                        {
+                            pThisR->u32Magic            = RTPIPE_MAGIC;
+                            pThisW->u32Magic            = RTPIPE_MAGIC;
+                            pThisR->hPipe               = hPipeR;
+                            pThisW->hPipe               = hPipeW;
+                            pThisR->fRead               = true;
+                            pThisW->fRead               = false;
+                            pThisR->fLeaveOpen          = false;
+                            pThisW->fLeaveOpen          = false;
+                            //pThisR->fIOPending        = false;
+                            //pThisW->fIOPending        = false;
+                            //pThisR->fZeroByteRead     = false;
+                            //pThisW->fZeroByteRead     = false;
+                            //pThisR->fBrokenPipe       = false;
+                            //pThisW->fBrokenPipe       = false;
+                            //pThisW->fPromisedWritable = false;
+                            //pThisR->fPromisedWritable = false;
+                            pThisW->fCreatedInheritable = RT_BOOL(fFlags & RTPIPE_C_INHERIT_WRITE);
+                            pThisR->fCreatedInheritable = RT_BOOL(fFlags & RTPIPE_C_INHERIT_READ);
+                            //pThisR->cUsers            = 0;
+                            //pThisW->cUsers            = 0;
+                            //pThisR->pbBounceBuf       = NULL;
+                            //pThisW->pbBounceBuf       = NULL;
+                            //pThisR->cbBounceBufUsed   = 0;
+                            //pThisW->cbBounceBufUsed   = 0;
+                            //pThisR->cbBounceBufAlloc  = 0;
+                            //pThisW->cbBounceBufAlloc  = 0;
+                            pThisR->hPollSet            = NIL_RTPOLLSET;
+                            pThisW->hPollSet            = NIL_RTPOLLSET;
+
+                            *phPipeRead  = pThisR;
+                            *phPipeWrite = pThisW;
+                            return VINF_SUCCESS;
+                        }
+                        CloseHandle(pThisR->Overlapped.hEvent);
+                    }
+                    RTCritSectDelete(&pThisW->CritSect);
+                }
+                RTCritSectDelete(&pThisR->CritSect);
+            }
+            RTMemFree(pThisW);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+        RTMemFree(pThisR);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    CloseHandle(hPipeR);
+    CloseHandle(hPipeW);
+    return rc;
+}
+
+
+/**
+ * Common worker for handling I/O completion.
+ *
+ * This is used by RTPipeClose, RTPipeWrite and RTPipeWriteBlocking.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ */
+static int rtPipeWriteCheckCompletion(RTPIPEINTERNAL *pThis)
+{
+    int rc;
+    DWORD dwRc = WaitForSingleObject(pThis->Overlapped.hEvent, 0);
+    if (dwRc == WAIT_OBJECT_0)
+    {
+        DWORD cbWritten = 0;
+        if (GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbWritten, TRUE))
+        {
+            for (;;)
+            {
+                if (cbWritten >= pThis->cbBounceBufUsed)
+                {
+                    pThis->fIOPending = false;
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+
+                /* resubmit the remainder of the buffer - can this actually happen? */
+                pThis->cbBounceBufUsed -= cbWritten;
+                memmove(&pThis->pbBounceBuf[0], &pThis->pbBounceBuf[cbWritten], pThis->cbBounceBufUsed);
+                rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+                if (!WriteFile(pThis->hPipe, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed, &cbWritten, &pThis->Overlapped))
+                {
+                    DWORD const dwErr = GetLastError();
+                    if (dwErr == ERROR_IO_PENDING)
+                        rc = VINF_TRY_AGAIN;
+                    else
+                    {
+                        pThis->fIOPending = false;
+                        if (dwErr == ERROR_NO_DATA)
+                            rc = VERR_BROKEN_PIPE;
+                        else
+                            rc = RTErrConvertFromWin32(GetLastError());
+                        if (rc == VERR_BROKEN_PIPE)
+                            pThis->fBrokenPipe = true;
+                    }
+                    break;
+                }
+                Assert(cbWritten > 0);
+            }
+        }
+        else
+        {
+            pThis->fIOPending = false;
+            rc = RTErrConvertFromWin32(GetLastError());
+        }
+    }
+    else if (dwRc == WAIT_TIMEOUT)
+        rc = VINF_TRY_AGAIN;
+    else
+    {
+        pThis->fIOPending = false;
+        if (dwRc == WAIT_ABANDONED)
+            rc = VERR_INVALID_HANDLE;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    return rc;
+}
+
+
+
+RTDECL(int)  RTPipeCloseEx(RTPIPE hPipe, bool fLeaveOpen)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    if (pThis == NIL_RTPIPE)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTPIPE_MAGIC, RTPIPE_MAGIC), VERR_INVALID_HANDLE);
+    RTCritSectEnter(&pThis->CritSect);
+    Assert(pThis->cUsers == 0);
+
+    if (!pThis->fRead && pThis->fIOPending)
+        rtPipeWriteCheckCompletion(pThis);
+
+    if (!fLeaveOpen && !pThis->fLeaveOpen)
+        CloseHandle(pThis->hPipe);
+    pThis->hPipe = INVALID_HANDLE_VALUE;
+
+    CloseHandle(pThis->Overlapped.hEvent);
+    pThis->Overlapped.hEvent = NULL;
+
+    RTMemFree(pThis->pbBounceBuf);
+    pThis->pbBounceBuf = NULL;
+
+    RTCritSectLeave(&pThis->CritSect);
+    RTCritSectDelete(&pThis->CritSect);
+
+    RTMemFree(pThis);
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int)  RTPipeClose(RTPIPE hPipe)
+{
+    return RTPipeCloseEx(hPipe, false /*fLeaveOpen*/);
+}
+
+
+RTDECL(int)  RTPipeFromNative(PRTPIPE phPipe, RTHCINTPTR hNativePipe, uint32_t fFlags)
+{
+    AssertPtrReturn(phPipe, VERR_INVALID_POINTER);
+    AssertReturn(!(fFlags & ~RTPIPE_N_VALID_MASK_FN), VERR_INVALID_PARAMETER);
+    AssertReturn(!!(fFlags & RTPIPE_N_READ) != !!(fFlags & RTPIPE_N_WRITE), VERR_INVALID_PARAMETER);
+
+    /*
+     * Get and validate the pipe handle info.
+     */
+    HANDLE hNative = (HANDLE)hNativePipe;
+    AssertReturn(GetFileType(hNative) == FILE_TYPE_PIPE, VERR_INVALID_HANDLE);
+
+    DWORD cMaxInstances;
+    DWORD fInfo;
+    if (!GetNamedPipeInfo(hNative, &fInfo, NULL, NULL, &cMaxInstances))
+        return RTErrConvertFromWin32(GetLastError());
+    /* Doesn't seem to matter to much if the pipe is message or byte type. Cygwin
+       seems to hand us such pipes when capturing output (@bugref{9397}), so just
+       ignore skip this check:
+    AssertReturn(!(fInfo & PIPE_TYPE_MESSAGE), VERR_INVALID_HANDLE); */
+    AssertReturn(cMaxInstances == 1, VERR_INVALID_HANDLE);
+
+    DWORD cInstances;
+    DWORD fState;
+    if (!GetNamedPipeHandleState(hNative, &fState, &cInstances, NULL, NULL, NULL, 0))
+        return RTErrConvertFromWin32(GetLastError());
+    AssertReturn(!(fState & PIPE_NOWAIT), VERR_INVALID_HANDLE);
+    AssertReturn(!(fState & PIPE_READMODE_MESSAGE), VERR_INVALID_HANDLE);
+    AssertReturn(cInstances <= 1, VERR_INVALID_HANDLE);
+
+    /*
+     * Looks kind of OK, create a handle so we can try rtPipeQueryNtInfo on it
+     * and see if we need to duplicate it to make that call work.
+     */
+    RTPIPEINTERNAL *pThis = (RTPIPEINTERNAL *)RTMemAllocZ(sizeof(RTPIPEINTERNAL));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+    int rc = RTCritSectInit(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        pThis->Overlapped.hEvent = CreateEvent(NULL, TRUE /*fManualReset*/,
+                                               TRUE /*fInitialState*/, NULL /*pName*/);
+        if (pThis->Overlapped.hEvent != NULL)
+        {
+            pThis->u32Magic             = RTPIPE_MAGIC;
+            pThis->hPipe                = hNative;
+            pThis->fRead                = RT_BOOL(fFlags & RTPIPE_N_READ);
+            pThis->fLeaveOpen           = RT_BOOL(fFlags & RTPIPE_N_LEAVE_OPEN);
+            //pThis->fIOPending         = false;
+            //pThis->fZeroByteRead      = false;
+            //pThis->fBrokenPipe        = false;
+            //pThis->fPromisedWritable  = false;
+            pThis->fCreatedInheritable  = RT_BOOL(fFlags & RTPIPE_N_INHERIT);
+            //pThis->cUsers             = 0;
+            //pThis->pbBounceBuf        = NULL;
+            //pThis->cbBounceBufUsed    = 0;
+            //pThis->cbBounceBufAlloc   = 0;
+            pThis->hPollSet             = NIL_RTPOLLSET;
+
+            HANDLE                      hNative2 = INVALID_HANDLE_VALUE;
+            FILE_PIPE_LOCAL_INFORMATION Info;
+            RT_ZERO(Info);
+            if (   g_pfnSetHandleInformation
+                && rtPipeQueryNtInfo(pThis, &Info))
+                rc = VINF_SUCCESS;
+            else
+            {
+                if (DuplicateHandle(GetCurrentProcess() /*hSrcProcess*/, hNative /*hSrcHandle*/,
+                                    GetCurrentProcess() /*hDstProcess*/, &hNative2 /*phDstHandle*/,
+                                    pThis->fRead ? GENERIC_READ : GENERIC_WRITE | FILE_READ_ATTRIBUTES /*dwDesiredAccess*/,
+                                    !!(fFlags & RTPIPE_N_INHERIT) /*fInheritHandle*/,
+                                    0 /*dwOptions*/))
+                {
+                    pThis->hPipe = hNative2;
+                    if (rtPipeQueryNtInfo(pThis, &Info))
+                    {
+                        pThis->fLeaveOpen = false;
+                        rc = VINF_SUCCESS;
+                    }
+                    else
+                    {
+                        rc = VERR_ACCESS_DENIED;
+                        CloseHandle(hNative2);
+                    }
+                }
+                else
+                    hNative2 = INVALID_HANDLE_VALUE;
+            }
+            if (RT_SUCCESS(rc))
+            {
+                /*
+                 * Verify the pipe state and correct the inheritability.
+                 */
+                AssertStmt(   Info.NamedPipeState == FILE_PIPE_CONNECTED_STATE
+                           || Info.NamedPipeState == FILE_PIPE_CLOSING_STATE
+                           || Info.NamedPipeState == FILE_PIPE_DISCONNECTED_STATE,
+                           VERR_INVALID_HANDLE);
+                AssertStmt(      Info.NamedPipeConfiguration
+                              == (   Info.NamedPipeEnd == FILE_PIPE_SERVER_END
+                                  ? (pThis->fRead ? FILE_PIPE_INBOUND  : FILE_PIPE_OUTBOUND)
+                                  : (pThis->fRead ? FILE_PIPE_OUTBOUND : FILE_PIPE_INBOUND) )
+                           || Info.NamedPipeConfiguration == FILE_PIPE_FULL_DUPLEX,
+                           VERR_INVALID_HANDLE);
+                if (   RT_SUCCESS(rc)
+                    && hNative2 == INVALID_HANDLE_VALUE
+                    && !g_pfnSetHandleInformation(hNative,
+                                                  HANDLE_FLAG_INHERIT /*dwMask*/,
+                                                  fFlags & RTPIPE_N_INHERIT ? HANDLE_FLAG_INHERIT : 0))
+                {
+                    rc = RTErrConvertFromWin32(GetLastError());
+                    AssertMsgFailed(("%Rrc\n", rc));
+                }
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * Ok, we're good!  If we replaced the handle, make sure it's not a standard
+                     * handle if we think we need to close it.
+                     */
+                    if (hNative2 != INVALID_HANDLE_VALUE)
+                    {
+                        if (   !(fFlags & RTPIPE_N_LEAVE_OPEN)
+                            && hNative != GetStdHandle(STD_INPUT_HANDLE)
+                            && hNative != GetStdHandle(STD_OUTPUT_HANDLE)
+                            && hNative != GetStdHandle(STD_ERROR_HANDLE) )
+                            CloseHandle(hNative);
+                    }
+                    *phPipe = pThis;
+                    return VINF_SUCCESS;
+                }
+            }
+
+            /* Bail out. */
+            if (hNative2 != INVALID_HANDLE_VALUE)
+                CloseHandle(hNative2);
+            CloseHandle(pThis->Overlapped.hEvent);
+        }
+        RTCritSectDelete(&pThis->CritSect);
+    }
+    RTMemFree(pThis);
+    return rc;
+}
+
+
+RTDECL(RTHCINTPTR) RTPipeToNative(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, -1);
+
+    return (RTHCINTPTR)pThis->hPipe;
+}
+
+
+RTDECL(int) RTPipeGetCreationInheritability(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, false);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, false);
+
+    return pThis->fCreatedInheritable;
+}
+
+
+RTDECL(int) RTPipeRead(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbRead);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /* No concurrent readers, sorry. */
+        if (pThis->cUsers == 0)
+        {
+            pThis->cUsers++;
+
+            /*
+             * Kick off a an overlapped read.  It should return immediately if
+             * there are bytes in the buffer.  If not, we'll cancel it and see
+             * what we get back.
+             */
+            rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+            DWORD cbRead = 0;
+            if (   cbToRead == 0
+                || ReadFile(pThis->hPipe, pvBuf,
+                            cbToRead <= ~(DWORD)0 ? (DWORD)cbToRead : ~(DWORD)0,
+                            &cbRead, &pThis->Overlapped))
+            {
+                *pcbRead = cbRead;
+                rc = VINF_SUCCESS;
+            }
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                pThis->fIOPending = true;
+                RTCritSectLeave(&pThis->CritSect);
+
+                /* We use NtCancelIoFile here because the CancelIo API
+                   providing access to it wasn't available till NT4.  This
+                   code needs to work (or at least load) with NT 3.1 */
+                IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+                NTSTATUS rcNt = NtCancelIoFile(pThis->hPipe, &Ios);
+                if (!NT_SUCCESS(rcNt))
+                    WaitForSingleObject(pThis->Overlapped.hEvent, INFINITE);
+
+                if (GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbRead, TRUE /*fWait*/))
+                {
+                    *pcbRead = cbRead;
+                    rc = VINF_SUCCESS;
+                }
+                else if (GetLastError() == ERROR_OPERATION_ABORTED)
+                {
+                    *pcbRead = 0;
+                    rc = VINF_TRY_AGAIN;
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+
+                RTCritSectEnter(&pThis->CritSect);
+                pThis->fIOPending = false;
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeReadBlocking(RTPIPE hPipe, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /* No concurrent readers, sorry. */
+        if (pThis->cUsers == 0)
+        {
+            pThis->cUsers++;
+
+            size_t cbTotalRead = 0;
+            while (cbToRead > 0)
+            {
+                /*
+                 * Kick of a an overlapped read.  It should return immediately if
+                 * there is bytes in the buffer.  If not, we'll cancel it and see
+                 * what we get back.
+                 */
+                rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+                DWORD cbRead = 0;
+                pThis->fIOPending = true;
+                RTCritSectLeave(&pThis->CritSect);
+
+                if (ReadFile(pThis->hPipe, pvBuf,
+                             cbToRead <= ~(DWORD)0 ? (DWORD)cbToRead : ~(DWORD)0,
+                             &cbRead, &pThis->Overlapped))
+                    rc = VINF_SUCCESS;
+                else if (GetLastError() == ERROR_IO_PENDING)
+                {
+                    WaitForSingleObject(pThis->Overlapped.hEvent, INFINITE);
+                    if (GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbRead, TRUE /*fWait*/))
+                        rc = VINF_SUCCESS;
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+
+                RTCritSectEnter(&pThis->CritSect);
+                pThis->fIOPending = false;
+                if (RT_FAILURE(rc))
+                    break;
+
+                /* advance */
+                cbToRead    -= cbRead;
+                cbTotalRead += cbRead;
+                pvBuf        = (uint8_t *)pvBuf + cbRead;
+            }
+
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+
+            if (pcbRead)
+            {
+                *pcbRead = cbTotalRead;
+                if (   RT_FAILURE(rc)
+                    && cbTotalRead
+                    && rc != VERR_INVALID_POINTER)
+                    rc = VINF_SUCCESS;
+            }
+
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeWrite(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pcbWritten);
+    AssertPtr(pvBuf);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /* No concurrent writers, sorry. */
+        if (pThis->cUsers == 0)
+        {
+            pThis->cUsers++;
+
+            /* If I/O is pending, check if it has completed. */
+            if (pThis->fIOPending)
+                rc = rtPipeWriteCheckCompletion(pThis);
+            else
+                rc = VINF_SUCCESS;
+            if (rc == VINF_SUCCESS)
+            {
+                Assert(!pThis->fIOPending);
+
+                /* Adjust the number of bytes to write to fit into the current
+                   buffer quota, unless we've promised stuff in RTPipeSelectOne.
+                   WriteQuotaAvailable better not be zero when it shouldn't!! */
+                FILE_PIPE_LOCAL_INFORMATION Info;
+                if (   !pThis->fPromisedWritable
+                    && cbToWrite > 0
+                    && rtPipeQueryNtInfo(pThis, &Info))
+                {
+                    if (Info.NamedPipeState == FILE_PIPE_CLOSING_STATE)
+                        rc = VERR_BROKEN_PIPE;
+                    /** @todo fixme: To get the pipe writing support to work the
+                     *               block below needs to be commented out until a
+                     *               way is found to address the problem of the incorrectly
+                     *               set field Info.WriteQuotaAvailable.
+                     * Update: We now just write up to RTPIPE_NT_SIZE more.  This is quite
+                     *         possibely what lead to the misunderstanding here wrt to
+                     *         WriteQuotaAvailable updating. */
+#if 0
+                    else if (   cbToWrite >= Info.WriteQuotaAvailable
+                             && Info.OutboundQuota != 0
+                             && (Info.WriteQuotaAvailable || pThis->cbBounceBufAlloc)
+                            )
+                    {
+                        cbToWrite = Info.WriteQuotaAvailable;
+                        if (!cbToWrite)
+                            rc = VINF_TRY_AGAIN;
+                    }
+#endif
+                }
+                pThis->fPromisedWritable = false;
+
+                /* Do the bounce buffering. */
+                if (    pThis->cbBounceBufAlloc < cbToWrite
+                    &&  pThis->cbBounceBufAlloc < RTPIPE_NT_SIZE)
+                {
+                    if (cbToWrite > RTPIPE_NT_SIZE)
+                        cbToWrite = RTPIPE_NT_SIZE;
+                    void *pv = RTMemRealloc(pThis->pbBounceBuf, RT_ALIGN_Z(cbToWrite, _1K));
+                    if (pv)
+                    {
+                        pThis->pbBounceBuf = (uint8_t *)pv;
+                        pThis->cbBounceBufAlloc = RT_ALIGN_Z(cbToWrite, _1K);
+                    }
+                    else
+                        rc = VERR_NO_MEMORY;
+                }
+                else if (cbToWrite > RTPIPE_NT_SIZE)
+                    cbToWrite = RTPIPE_NT_SIZE;
+                if (RT_SUCCESS(rc) && cbToWrite)
+                {
+                    memcpy(pThis->pbBounceBuf, pvBuf, cbToWrite);
+                    pThis->cbBounceBufUsed = (uint32_t)cbToWrite;
+
+                    /* Submit the write. */
+                    rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+                    DWORD cbWritten = 0;
+                    if (WriteFile(pThis->hPipe, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                                  &cbWritten, &pThis->Overlapped))
+                    {
+                        *pcbWritten = RT_MIN(cbWritten, cbToWrite); /* paranoia^3 */
+                        rc = VINF_SUCCESS;
+                    }
+                    else if (GetLastError() == ERROR_IO_PENDING)
+                    {
+                        *pcbWritten = cbToWrite;
+                        pThis->fIOPending = true;
+                        rc = VINF_SUCCESS;
+                    }
+                    else if (GetLastError() == ERROR_NO_DATA)
+                        rc = VERR_BROKEN_PIPE;
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                }
+                else if (RT_SUCCESS(rc))
+                    *pcbWritten = 0;
+            }
+            else if (RT_SUCCESS(rc))
+                *pcbWritten = 0;
+
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+}
+
+
+RTDECL(int) RTPipeWriteBlocking(RTPIPE hPipe, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+    AssertPtr(pvBuf);
+    AssertPtrNull(pcbWritten);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /* No concurrent writers, sorry. */
+        if (pThis->cUsers == 0)
+        {
+            pThis->cUsers++;
+
+            /*
+             * If I/O is pending, wait for it to complete.
+             */
+            if (pThis->fIOPending)
+            {
+                rc = rtPipeWriteCheckCompletion(pThis);
+                while (rc == VINF_TRY_AGAIN)
+                {
+                    Assert(pThis->fIOPending);
+                    HANDLE hEvent = pThis->Overlapped.hEvent;
+                    RTCritSectLeave(&pThis->CritSect);
+                    WaitForSingleObject(hEvent, INFINITE);
+                    RTCritSectEnter(&pThis->CritSect);
+                }
+            }
+            if (RT_SUCCESS(rc))
+            {
+                Assert(!pThis->fIOPending);
+                pThis->fPromisedWritable = false;
+
+                /*
+                 * Try write everything.
+                 * No bounce buffering, cUsers protects us.
+                 */
+                size_t cbTotalWritten = 0;
+                while (cbToWrite > 0)
+                {
+                    rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+                    pThis->fIOPending = true;
+                    RTCritSectLeave(&pThis->CritSect);
+
+                    DWORD cbWritten = 0;
+                    DWORD const cbToWriteInThisIteration = cbToWrite <= ~(DWORD)0 ? (DWORD)cbToWrite : ~(DWORD)0;
+                    if (WriteFile(pThis->hPipe, pvBuf, cbToWriteInThisIteration, &cbWritten, &pThis->Overlapped))
+                        rc = VINF_SUCCESS;
+                    else if (GetLastError() == ERROR_IO_PENDING)
+                    {
+                        WaitForSingleObject(pThis->Overlapped.hEvent, INFINITE);
+                        if (GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbWritten, TRUE /*fWait*/))
+                            rc = VINF_SUCCESS;
+                        else
+                            rc = RTErrConvertFromWin32(GetLastError());
+                    }
+                    else if (GetLastError() == ERROR_NO_DATA)
+                        rc = VERR_BROKEN_PIPE;
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+
+                    RTCritSectEnter(&pThis->CritSect);
+                    pThis->fIOPending = false;
+                    if (RT_FAILURE(rc))
+                        break;
+
+                    /* advance */
+                    if (cbWritten > cbToWriteInThisIteration) /* paranoia^3 */
+                        cbWritten = cbToWriteInThisIteration;
+                    pvBuf           = (char const *)pvBuf + cbWritten;
+                    cbTotalWritten += cbWritten;
+                    cbToWrite      -= cbWritten;
+                }
+
+                if (pcbWritten)
+                {
+                    *pcbWritten = cbTotalWritten;
+                    if (   RT_FAILURE(rc)
+                        && cbTotalWritten
+                        && rc != VERR_INVALID_POINTER)
+                        rc = VINF_SUCCESS;
+                }
+            }
+
+            if (rc == VERR_BROKEN_PIPE)
+                pThis->fBrokenPipe = true;
+
+            pThis->cUsers--;
+        }
+        else
+            rc = VERR_WRONG_ORDER;
+        RTCritSectLeave(&pThis->CritSect);
+    }
+    return rc;
+
+#if 0 /** @todo r=bird: What's this? */
+    int rc = rtPipeTryBlocking(pThis);
+    if (RT_SUCCESS(rc))
+    {
+        size_t cbTotalWritten = 0;
+        while (cbToWrite > 0)
+        {
+            ssize_t cbWritten = write(pThis->fd, pvBuf, RT_MIN(cbToWrite, SSIZE_MAX));
+            if (cbWritten < 0)
+            {
+                rc = RTErrConvertFromErrno(errno);
+                break;
+            }
+
+            /* advance */
+            pvBuf           = (char const *)pvBuf + cbWritten;
+            cbTotalWritten += cbWritten;
+            cbToWrite      -= cbWritten;
+        }
+
+        if (pcbWritten)
+        {
+            *pcbWritten = cbTotalWritten;
+            if (   RT_FAILURE(rc)
+                && cbTotalWritten
+                && rc != VERR_INVALID_POINTER)
+                rc = VINF_SUCCESS;
+        }
+
+        ASMAtomicDecU32(&pThis->u32State);
+    }
+    return rc;
+#endif
+}
+
+
+RTDECL(int) RTPipeFlush(RTPIPE hPipe)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->fRead, VERR_ACCESS_DENIED);
+
+    if (!FlushFileBuffers(pThis->hPipe))
+    {
+        int rc = RTErrConvertFromWin32(GetLastError());
+        if (rc == VERR_BROKEN_PIPE)
+            pThis->fBrokenPipe = true;
+        return rc;
+    }
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTPipeSelectOne(RTPIPE hPipe, RTMSINTERVAL cMillies)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    uint64_t const StartMsTS = RTTimeMilliTS();
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_FAILURE(rc))
+        return rc;
+    for (unsigned iLoop = 0;; iLoop++)
+    {
+        HANDLE  hWait = INVALID_HANDLE_VALUE;
+        if (pThis->fRead)
+        {
+            if (pThis->fIOPending)
+                hWait = pThis->Overlapped.hEvent;
+            else
+            {
+                /* Peek at the pipe buffer and see how many bytes it contains. */
+                DWORD cbAvailable;
+                if (   PeekNamedPipe(pThis->hPipe, NULL, 0, NULL, &cbAvailable, NULL)
+                    && cbAvailable > 0)
+                {
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+
+                /* Start a zero byte read operation that we can wait on. */
+                if (cMillies == 0)
+                {
+                    rc = VERR_TIMEOUT;
+                    break;
+                }
+                AssertBreakStmt(pThis->cUsers == 0, rc = VERR_INTERNAL_ERROR_5);
+                rc = ResetEvent(pThis->Overlapped.hEvent); Assert(rc == TRUE);
+                DWORD cbRead = 0;
+                if (ReadFile(pThis->hPipe, pThis->abBuf, 0, &cbRead, &pThis->Overlapped))
+                {
+                    rc = VINF_SUCCESS;
+                    if (iLoop > 10)
+                        RTThreadYield();
+                }
+                else if (GetLastError() == ERROR_IO_PENDING)
+                {
+                    pThis->cUsers++;
+                    pThis->fIOPending = true;
+                    pThis->fZeroByteRead = true;
+                    hWait = pThis->Overlapped.hEvent;
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+        }
+        else
+        {
+            if (pThis->fIOPending)
+            {
+                rc = rtPipeWriteCheckCompletion(pThis);
+                if (RT_FAILURE(rc))
+                    break;
+            }
+            if (pThis->fIOPending)
+                hWait = pThis->Overlapped.hEvent;
+            else
+            {
+                FILE_PIPE_LOCAL_INFORMATION Info;
+#if 1
+                /* We can always write one bounce buffer full of data regardless of
+                   the pipe buffer state.  We must of course take this into account,
+                   or code like "Full write buffer" test in tstRTPipe gets confused. */
+                rc = VINF_SUCCESS;
+                if (rtPipeQueryNtInfo(pThis, &Info))
+                {
+                    /* Check for broken pipe. */
+                    if (Info.NamedPipeState != FILE_PIPE_CLOSING_STATE)
+                        pThis->fPromisedWritable = true;
+                    else
+                        rc = VERR_BROKEN_PIPE;
+                }
+                else
+                    pThis->fPromisedWritable = true;
+                break;
+
+#else /* old code: */
+                if (rtPipeQueryNtInfo(pThis, &Info))
+                {
+                    /* Check for broken pipe. */
+                    if (Info.NamedPipeState == FILE_PIPE_CLOSING_STATE)
+                    {
+                        rc = VERR_BROKEN_PIPE;
+                        break;
+                    }
+
+                    /* Check for available write buffer space. */
+                    if (Info.WriteQuotaAvailable > 0)
+                    {
+                        pThis->fPromisedWritable = false;
+                        rc = VINF_SUCCESS;
+                        break;
+                    }
+
+                    /* delayed buffer alloc or timeout: phony promise
+                       later: See if we still can associate a semaphore with
+                              the pipe, like on OS/2. */
+                    if (Info.OutboundQuota == 0 || cMillies)
+                    {
+                        pThis->fPromisedWritable = true;
+                        rc = VINF_SUCCESS;
+                        break;
+                    }
+                }
+                else
+                {
+                    pThis->fPromisedWritable = true;
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+#endif
+            }
+        }
+        if (RT_FAILURE(rc))
+            break;
+
+        /*
+         * Check for timeout.
+         */
+        DWORD cMsMaxWait = INFINITE;
+        if (   cMillies != RT_INDEFINITE_WAIT
+            && (   hWait != INVALID_HANDLE_VALUE
+                || iLoop > 10)
+           )
+        {
+            uint64_t cElapsed = RTTimeMilliTS() - StartMsTS;
+            if (cElapsed >= cMillies)
+            {
+                rc = VERR_TIMEOUT;
+                break;
+            }
+            cMsMaxWait = cMillies - (uint32_t)cElapsed;
+        }
+
+        /*
+         * Wait.
+         */
+        if (hWait != INVALID_HANDLE_VALUE)
+        {
+            RTCritSectLeave(&pThis->CritSect);
+
+            DWORD dwRc = WaitForSingleObject(hWait, cMsMaxWait);
+            if (dwRc == WAIT_OBJECT_0)
+                rc = VINF_SUCCESS;
+            else if (dwRc == WAIT_TIMEOUT)
+                rc = VERR_TIMEOUT;
+            else if (dwRc == WAIT_ABANDONED)
+                rc = VERR_INVALID_HANDLE;
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+            if (   RT_FAILURE(rc)
+                && pThis->u32Magic != RTPIPE_MAGIC)
+                return rc;
+
+            RTCritSectEnter(&pThis->CritSect);
+            if (pThis->fZeroByteRead)
+            {
+                pThis->cUsers--;
+                pThis->fIOPending = false;
+                if (rc != VINF_SUCCESS)
+                {
+                    IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+                    NtCancelIoFile(pThis->hPipe, &Ios);
+                }
+                DWORD cbRead = 0;
+                GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbRead, TRUE /*fWait*/);
+            }
+            if (RT_FAILURE(rc))
+                break;
+        }
+    }
+
+    if (rc == VERR_BROKEN_PIPE)
+        pThis->fBrokenPipe = true;
+
+    RTCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+
+RTDECL(int) RTPipeQueryReadable(RTPIPE hPipe, size_t *pcbReadable)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->fRead, VERR_PIPE_NOT_READ);
+    AssertPtrReturn(pcbReadable, VERR_INVALID_POINTER);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /** @todo The file size should give the same info and be slightly faster... */
+    DWORD cbAvailable = 0;
+    if (PeekNamedPipe(pThis->hPipe, NULL, 0, NULL, &cbAvailable, NULL))
+    {
+#if ARCH_BITS == 32
+        /*
+         * Kludge!
+         *
+         * Prior to XP SP1 (?), the returned cbAvailable value was not adjusted
+         * by the read position in the current message/buffer, so it could
+         * potentially be too high.  This may cause the caller to try read more
+         * data than what's actually available, which may cause the read to
+         * block when the caller thought it wouldn't.
+         *
+         * To get an accurate readable size, we have to provide an output
+         * buffer and see how much we actually get back in it, as the data
+         * peeking works correctly (as you would expect).
+         */
+        if (cbAvailable == 0 || g_enmWinVer >= kRTWinOSType_XP64)
+        { /* No data available or kernel shouldn't be affected. */ }
+        else
+        {
+            for (unsigned i = 0; ; i++)
+            {
+                uint8_t abBufStack[_16K];
+                void   *pvBufFree = NULL;
+                void   *pvBuf;
+                DWORD   cbBuf     = RT_ALIGN_32(cbAvailable + i * 256, 64);
+                if (cbBuf <= sizeof(abBufStack))
+                {
+                    pvBuf = abBufStack;
+                    /* No cbBuf = sizeof(abBufStack) here! PeekNamedPipe bounce buffers the request on the heap. */
+                }
+                else
+                {
+                    pvBufFree = pvBuf = RTMemTmpAlloc(cbBuf);
+                    if (!pvBuf)
+                    {
+                        rc = VERR_NO_TMP_MEMORY;
+                        cbAvailable = 1;
+                        break;
+                    }
+                }
+
+                DWORD cbAvailable2 = 0;
+                DWORD cbRead       = 0;
+                BOOL fRc = PeekNamedPipe(pThis->hPipe, pvBuf, cbBuf, &cbRead, &cbAvailable2, NULL);
+                Log(("RTPipeQueryReadable: #%u: cbAvailable=%#x cbRead=%#x cbAvailable2=%#x (cbBuf=%#x)\n",
+                     i, cbAvailable, cbRead, cbAvailable2, cbBuf));
+
+                RTMemTmpFree(pvBufFree);
+
+                if (fRc)
+                {
+                    if (cbAvailable2 <= cbBuf || i >= 10)
+                        cbAvailable = cbRead;
+                    else
+                    {
+                        cbAvailable = cbAvailable2;
+                        continue;
+                    }
+                }
+                else
+                {
+                    rc = RTErrConvertFromWin32(GetLastError());
+                    cbAvailable = 1;
+                }
+                break;
+            }
+        }
+#endif
+        *pcbReadable = cbAvailable;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    RTCritSectLeave(&pThis->CritSect);
+    return rc;
+}
+
+
+RTDECL(int) RTPipeQueryInfo(RTPIPE hPipe, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, 0);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, 0);
+
+    rtPipeFakeQueryInfo(pObjInfo, enmAddAttr, pThis->fRead);
+
+    FILE_PIPE_LOCAL_INFORMATION Info;
+    if (rtPipeQueryNtInfo(pThis, &Info))
+    {
+        pObjInfo->cbAllocated = pThis->fRead ? Info.InboundQuota : Info.OutboundQuota;
+        pObjInfo->cbObject    = pThis->fRead ? Info.ReadDataAvailable : Info.WriteQuotaAvailable;
+    }
+
+    RTCritSectLeave(&pThis->CritSect);
+    return VINF_SUCCESS;
+}
+
+
+int rtPipePollGetHandle(RTPIPE hPipe, uint32_t fEvents, PRTHCINTPTR phNative)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, VERR_INVALID_HANDLE);
+
+    AssertReturn(!(fEvents & RTPOLL_EVT_READ)  || pThis->fRead,  VERR_INVALID_PARAMETER);
+    AssertReturn(!(fEvents & RTPOLL_EVT_WRITE) || !pThis->fRead, VERR_INVALID_PARAMETER);
+
+    /* Later: Try register an event handle with the pipe like on OS/2, there is
+       a file control for doing this obviously intended for the OS/2 subsys.
+       The question is whether this still exists on Vista and W7. */
+    *phNative = (RTHCINTPTR)pThis->Overlapped.hEvent;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Checks for pending events.
+ *
+ * @returns Event mask or 0.
+ * @param   pThis               The pipe handle.
+ * @param   fEvents             The desired events.
+ */
+static uint32_t rtPipePollCheck(RTPIPEINTERNAL *pThis, uint32_t fEvents)
+{
+    uint32_t fRetEvents = 0;
+    if (pThis->fBrokenPipe)
+        fRetEvents |= RTPOLL_EVT_ERROR;
+    else if (pThis->fRead)
+    {
+        if (!pThis->fIOPending)
+        {
+            DWORD cbAvailable;
+            if (PeekNamedPipe(pThis->hPipe, NULL, 0, NULL, &cbAvailable, NULL))
+            {
+                if (   (fEvents & RTPOLL_EVT_READ)
+                    && cbAvailable > 0)
+                    fRetEvents |= RTPOLL_EVT_READ;
+            }
+            else
+            {
+                if (GetLastError() == ERROR_BROKEN_PIPE)
+                    pThis->fBrokenPipe = true;
+                fRetEvents |= RTPOLL_EVT_ERROR;
+            }
+        }
+    }
+    else
+    {
+        if (pThis->fIOPending)
+        {
+            rtPipeWriteCheckCompletion(pThis);
+            if (pThis->fBrokenPipe)
+                fRetEvents |= RTPOLL_EVT_ERROR;
+        }
+        if (   !pThis->fIOPending
+            && !fRetEvents)
+        {
+            FILE_PIPE_LOCAL_INFORMATION Info;
+            if (rtPipeQueryNtInfo(pThis, &Info))
+            {
+                /* Check for broken pipe. */
+                if (Info.NamedPipeState == FILE_PIPE_CLOSING_STATE)
+                {
+                    fRetEvents = RTPOLL_EVT_ERROR;
+                    pThis->fBrokenPipe = true;
+                }
+
+                /* Check if there is available buffer space. */
+                if (   !fRetEvents
+                    && (fEvents & RTPOLL_EVT_WRITE)
+                    && (   Info.WriteQuotaAvailable > 0
+                        || Info.OutboundQuota == 0)
+                    )
+                    fRetEvents |= RTPOLL_EVT_WRITE;
+            }
+            else if (fEvents & RTPOLL_EVT_WRITE)
+                fRetEvents |= RTPOLL_EVT_WRITE;
+        }
+    }
+
+    return fRetEvents;
+}
+
+
+/**
+ * Internal RTPoll helper that polls the pipe handle and, if @a fNoWait is
+ * clear, starts whatever actions we've got running during the poll call.
+ *
+ * @returns 0 if no pending events, actions initiated if @a fNoWait is clear.
+ *          Event mask (in @a fEvents) and no actions if the handle is ready
+ *          already.
+ *          UINT32_MAX (asserted) if the pipe handle is busy in I/O or a
+ *          different poll set.
+ *
+ * @param   hPipe               The pipe handle.
+ * @param   hPollSet            The poll set handle (for access checks).
+ * @param   fEvents             The events we're polling for.
+ * @param   fFinalEntry         Set if this is the final entry for this handle
+ *                              in this poll set.  This can be used for dealing
+ *                              with duplicate entries.
+ * @param   fNoWait             Set if it's a zero-wait poll call.  Clear if
+ *                              we'll wait for an event to occur.
+ */
+uint32_t rtPipePollStart(RTPIPE hPipe, RTPOLLSET hPollSet, uint32_t fEvents, bool fFinalEntry, bool fNoWait)
+{
+    /** @todo All this polling code could be optimized to make fewer system
+     *        calls; like for instance the ResetEvent calls. */
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, UINT32_MAX);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, UINT32_MAX);
+    RT_NOREF_PV(fFinalEntry);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, UINT32_MAX);
+
+    /* Check that this is the only current use of this pipe. */
+    uint32_t fRetEvents;
+    if (   pThis->cUsers   == 0
+        || pThis->hPollSet == hPollSet)
+    {
+        /* Check what the current events are. */
+        fRetEvents = rtPipePollCheck(pThis, fEvents);
+        if (   !fRetEvents
+            && !fNoWait)
+        {
+            /* Make sure the event semaphore has been reset. */
+            if (!pThis->fIOPending)
+            {
+                rc = ResetEvent(pThis->Overlapped.hEvent);
+                Assert(rc == TRUE);
+            }
+
+            /* Kick off the zero byte read thing if applicable. */
+            if (   !pThis->fIOPending
+                && pThis->fRead
+                && (fEvents & RTPOLL_EVT_READ)
+               )
+            {
+                DWORD cbRead = 0;
+                if (ReadFile(pThis->hPipe, pThis->abBuf, 0, &cbRead, &pThis->Overlapped))
+                    fRetEvents = rtPipePollCheck(pThis, fEvents);
+                else if (GetLastError() == ERROR_IO_PENDING)
+                {
+                    pThis->fIOPending    = true;
+                    pThis->fZeroByteRead = true;
+                }
+                else
+                    fRetEvents = RTPOLL_EVT_ERROR;
+            }
+
+            /* If we're still set for the waiting, record the poll set and
+               mark the pipe used. */
+            if (!fRetEvents)
+            {
+                pThis->cUsers++;
+                pThis->hPollSet = hPollSet;
+            }
+        }
+    }
+    else
+    {
+        AssertFailed();
+        fRetEvents = UINT32_MAX;
+    }
+
+    RTCritSectLeave(&pThis->CritSect);
+    return fRetEvents;
+}
+
+
+/**
+ * Called after a WaitForMultipleObjects returned in order to check for pending
+ * events and stop whatever actions that rtPipePollStart() initiated.
+ *
+ * @returns Event mask or 0.
+ *
+ * @param   hPipe               The pipe handle.
+ * @param   fEvents             The events we're polling for.
+ * @param   fFinalEntry         Set if this is the final entry for this handle
+ *                              in this poll set.  This can be used for dealing
+ *                              with duplicate entries.  Only keep in mind that
+ *                              this method is called in reverse order, so the
+ *                              first call will have this set (when the entire
+ *                              set was processed).
+ * @param   fHarvestEvents      Set if we should check for pending events.
+ */
+uint32_t rtPipePollDone(RTPIPE hPipe, uint32_t fEvents, bool fFinalEntry, bool fHarvestEvents)
+{
+    RTPIPEINTERNAL *pThis = hPipe;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTPIPE_MAGIC, 0);
+    RT_NOREF_PV(fFinalEntry);
+    RT_NOREF_PV(fHarvestEvents);
+
+    int rc = RTCritSectEnter(&pThis->CritSect);
+    AssertRCReturn(rc, 0);
+
+    Assert(pThis->cUsers > 0);
+
+
+    /* Cancel the zero byte read. */
+    uint32_t fRetEvents = 0;
+    if (pThis->fZeroByteRead)
+    {
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NtCancelIoFile(pThis->hPipe, &Ios);
+
+        DWORD cbRead = 0;
+        if (   !GetOverlappedResult(pThis->hPipe, &pThis->Overlapped, &cbRead, TRUE /*fWait*/)
+            && GetLastError() != ERROR_OPERATION_ABORTED)
+            fRetEvents = RTPOLL_EVT_ERROR;
+
+        pThis->fIOPending    = false;
+        pThis->fZeroByteRead = false;
+    }
+
+    /* harvest events. */
+    fRetEvents |= rtPipePollCheck(pThis, fEvents);
+
+    /* update counters. */
+    pThis->cUsers--;
+    /** @todo This isn't sane, or is it? See OS/2 impl. */
+    if (!pThis->cUsers)
+        pThis->hPollSet = NIL_RTPOLLSET;
+
+    RTCritSectLeave(&pThis->CritSect);
+    return fRetEvents;
+}
+
diff --git a/src/VBox/Runtime/r3/win/process-win.cpp b/src/VBox/Runtime/r3/win/process-win.cpp
new file mode 100644
index 00000000..18ed9ab0
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/process-win.cpp
@@ -0,0 +1,2750 @@
+/* $Id: process-win.cpp $ */
+/** @file
+ * IPRT - Process, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/asm.h> /* hack */
+
+#include <iprt/nt/nt-and-windows.h>
+#include <Userenv.h>
+#include <tlhelp32.h>
+#ifndef IPRT_NO_CRT
+# include <process.h>
+# include <errno.h>
+# include <Strsafe.h>
+#endif
+#include <LsaLookup.h>
+#include <Lmcons.h>
+
+#define _NTDEF_ /* Prevents redefining (P)UNICODE_STRING. */
+#include <Ntsecapi.h>
+
+#include <iprt/process.h>
+#include "internal-r3-win.h"
+
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/env.h>
+#include <iprt/getopt.h>
+#include <iprt/initterm.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include <iprt/path.h>
+#include <iprt/pipe.h>
+#include <iprt/string.h>
+#include <iprt/socket.h>
+#include <iprt/utf16.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/* kernel32.dll: */
+//typedef DWORD   (WINAPI *PFNWTSGETACTIVECONSOLESESSIONID)(VOID);
+typedef HANDLE  (WINAPI *PFNCREATETOOLHELP32SNAPSHOT)(DWORD, DWORD);
+typedef BOOL    (WINAPI *PFNPROCESS32FIRSTW)(HANDLE, LPPROCESSENTRY32W);
+typedef BOOL    (WINAPI *PFNPROCESS32NEXTW)(HANDLE, LPPROCESSENTRY32W);
+
+/* psapi.dll: */
+typedef BOOL    (WINAPI *PFNENUMPROCESSES)(LPDWORD, DWORD, LPDWORD);
+typedef DWORD   (WINAPI *PFNGETMODULEBASENAMEW)(HANDLE, HMODULE, LPWSTR, DWORD);
+
+/* advapi32.dll: */
+typedef BOOL    (WINAPI *PFNCREATEPROCESSWITHLOGON)(LPCWSTR, LPCWSTR, LPCWSTR, DWORD, LPCWSTR, LPWSTR, DWORD,
+                                                    LPVOID, LPCWSTR, LPSTARTUPINFOW, LPPROCESS_INFORMATION);
+typedef NTSTATUS (NTAPI *PFNLSALOOKUPNAMES2)(LSA_HANDLE, ULONG, ULONG, PLSA_UNICODE_STRING,
+                                             PLSA_REFERENCED_DOMAIN_LIST*, PLSA_TRANSLATED_SID2*);
+
+/* userenv.dll: */
+typedef BOOL    (WINAPI *PFNCREATEENVIRONMENTBLOCK)(LPVOID *, HANDLE, BOOL);
+typedef BOOL    (WINAPI *PFNPFNDESTROYENVIRONMENTBLOCK)(LPVOID);
+typedef BOOL    (WINAPI *PFNLOADUSERPROFILEW)(HANDLE, LPPROFILEINFOW);
+typedef BOOL    (WINAPI *PFNUNLOADUSERPROFILE)(HANDLE, HANDLE);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Init once structure. */
+static RTONCE       g_rtProcWinInitOnce = RTONCE_INITIALIZER;
+/** Critical section protecting the process array. */
+static RTCRITSECT   g_CritSect;
+/** The number of processes in the array. */
+static uint32_t     g_cProcesses;
+/** The current allocation size. */
+static uint32_t     g_cProcessesAlloc;
+/** Array containing the live or non-reaped child processes. */
+static struct RTPROCWINENTRY
+{
+    /** The process ID. */
+    ULONG_PTR       pid;
+    /** The process handle. */
+    HANDLE          hProcess;
+}                  *g_paProcesses;
+
+/** Structure for storing a user's account info.
+ *  Must be free'd with rtProcWinFreeAccountInfo(). */
+typedef struct RTPROCWINACCOUNTINFO
+{
+    /** User name. */
+    PRTUTF16        pwszUserName;
+    /** Domain this account is tied to. Can be NULL if no domain is being used. */
+    PRTUTF16        pwszDomain;
+} RTPROCWINACCOUNTINFO, *PRTPROCWINACCOUNTINFO;
+
+/** @name userenv.dll imports (we don't unload it).
+ * They're all optional. So in addition to using g_rtProcWinResolveOnce, the
+ * caller must also check if any of the necessary APIs are NULL pointers.
+ * @{ */
+/** Init once structure for run-as-user functions we need. */
+static RTONCE                           g_rtProcWinResolveOnce          = RTONCE_INITIALIZER;
+/* kernel32.dll: */
+static PFNCREATETOOLHELP32SNAPSHOT      g_pfnCreateToolhelp32Snapshot   = NULL;
+static PFNPROCESS32FIRSTW               g_pfnProcess32FirstW            = NULL;
+static PFNPROCESS32NEXTW                g_pfnProcess32NextW             = NULL;
+/* psapi.dll: */
+static PFNGETMODULEBASENAMEW            g_pfnGetModuleBaseNameW         = NULL;
+static PFNENUMPROCESSES                 g_pfnEnumProcesses              = NULL;
+/* advapi32.dll: */
+static PFNCREATEPROCESSWITHLOGON        g_pfnCreateProcessWithLogonW    = NULL;
+static decltype(LogonUserW)            *g_pfnLogonUserW                 = NULL;
+static decltype(CreateProcessAsUserW)  *g_pfnCreateProcessAsUserW       = NULL;
+/* user32.dll: */
+static decltype(OpenWindowStationW)    *g_pfnOpenWindowStationW         = NULL;
+static decltype(CloseWindowStation)    *g_pfnCloseWindowStation        = NULL;
+/* userenv.dll: */
+static PFNCREATEENVIRONMENTBLOCK        g_pfnCreateEnvironmentBlock     = NULL;
+static PFNPFNDESTROYENVIRONMENTBLOCK    g_pfnDestroyEnvironmentBlock    = NULL;
+static PFNLOADUSERPROFILEW              g_pfnLoadUserProfileW           = NULL;
+static PFNUNLOADUSERPROFILE             g_pfnUnloadUserProfile          = NULL;
+/** @} */
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static int rtProcWinFindExe(uint32_t fFlags, RTENV hEnv, const char *pszExec, PRTUTF16 *ppwszExec);
+static int rtProcWinCreateEnvBlockAndFindExe(uint32_t fFlags, RTENV hEnv, const char *pszExec,
+                                             PRTUTF16 *ppwszzBlock, PRTUTF16 *ppwszExec);
+
+
+/**
+ * Clean up the globals.
+ *
+ * @param   enmReason           Ignored.
+ * @param   iStatus             Ignored.
+ * @param   pvUser              Ignored.
+ */
+static DECLCALLBACK(void) rtProcWinTerm(RTTERMREASON enmReason, int32_t iStatus, void *pvUser)
+{
+    NOREF(pvUser); NOREF(iStatus); NOREF(enmReason);
+
+    RTCritSectDelete(&g_CritSect);
+
+    size_t i = g_cProcesses;
+    while (i-- > 0)
+    {
+        CloseHandle(g_paProcesses[i].hProcess);
+        g_paProcesses[i].hProcess = NULL;
+    }
+    RTMemFree(g_paProcesses);
+
+    g_paProcesses     = NULL;
+    g_cProcesses      = 0;
+    g_cProcessesAlloc = 0;
+}
+
+
+/**
+ * Initialize the globals.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser              Ignored.
+ */
+static DECLCALLBACK(int32_t) rtProcWinInitOnce(void *pvUser)
+{
+    NOREF(pvUser);
+
+    g_cProcesses        = 0;
+    g_cProcessesAlloc   = 0;
+    g_paProcesses       = NULL;
+    int rc = RTCritSectInit(&g_CritSect);
+    if (RT_SUCCESS(rc))
+    {
+        /** @todo init once, terminate once - this is a generic thing which should
+         *        have some kind of static and simpler setup!  */
+        rc = RTTermRegisterCallback(rtProcWinTerm, NULL);
+        if (RT_SUCCESS(rc))
+            return rc;
+        RTCritSectDelete(&g_CritSect);
+    }
+    return rc;
+}
+
+
+/**
+ * Gets the process handle for a process from g_paProcesses.
+ *
+ * @returns Process handle if found, NULL if not.
+ * @param   pid                 The process to remove (pid).
+ */
+static HANDLE rtProcWinFindPid(RTPROCESS pid)
+{
+    HANDLE hProcess = NULL;
+
+    RTCritSectEnter(&g_CritSect);
+    uint32_t i = g_cProcesses;
+    while (i-- > 0)
+        if (g_paProcesses[i].pid == pid)
+        {
+            hProcess = g_paProcesses[i].hProcess;
+            break;
+        }
+    RTCritSectLeave(&g_CritSect);
+
+    return hProcess;
+}
+
+
+/**
+ * Removes a process from g_paProcesses and closes the process handle.
+ *
+ * @param   pid                 The process to remove (pid).
+ */
+static void rtProcWinRemovePid(RTPROCESS pid)
+{
+    RTCritSectEnter(&g_CritSect);
+    uint32_t i = g_cProcesses;
+    while (i-- > 0)
+        if (g_paProcesses[i].pid == pid)
+        {
+            HANDLE hProcess = g_paProcesses[i].hProcess;
+
+            g_cProcesses--;
+            uint32_t cToMove = g_cProcesses - i;
+            if (cToMove)
+                memmove(&g_paProcesses[i], &g_paProcesses[i + 1], cToMove * sizeof(g_paProcesses[0]));
+
+            RTCritSectLeave(&g_CritSect);
+            CloseHandle(hProcess);
+            return;
+        }
+    RTCritSectLeave(&g_CritSect);
+}
+
+
+/**
+ * Adds a process to g_paProcesses.
+ *
+ * @returns IPRT status code.
+ * @param   pid                 The process id.
+ * @param   hProcess            The process handle.
+ */
+static int rtProcWinAddPid(RTPROCESS pid, HANDLE hProcess)
+{
+    RTCritSectEnter(&g_CritSect);
+
+    uint32_t i = g_cProcesses;
+    if (i >= g_cProcessesAlloc)
+    {
+        void *pvNew = RTMemRealloc(g_paProcesses, (i + 16) * sizeof(g_paProcesses[0]));
+        if (RT_UNLIKELY(!pvNew))
+        {
+            RTCritSectLeave(&g_CritSect);
+            return VERR_NO_MEMORY;
+        }
+        g_paProcesses     = (struct RTPROCWINENTRY *)pvNew;
+        g_cProcessesAlloc = i + 16;
+    }
+
+    g_paProcesses[i].pid      = pid;
+    g_paProcesses[i].hProcess = hProcess;
+    g_cProcesses = i + 1;
+
+    RTCritSectLeave(&g_CritSect);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Initialize the import APIs for run-as-user and special environment support.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser              Ignored.
+ */
+static DECLCALLBACK(int) rtProcWinResolveOnce(void *pvUser)
+{
+    int      rc;
+    RTLDRMOD hMod;
+    RT_NOREF_PV(pvUser);
+
+    /*
+     * kernel32.dll APIs introduced after NT4.
+     */
+    g_pfnCreateToolhelp32Snapshot   = (PFNCREATETOOLHELP32SNAPSHOT)GetProcAddress(g_hModKernel32, "CreateToolhelp32Snapshot");
+    g_pfnProcess32FirstW            = (PFNPROCESS32FIRSTW         )GetProcAddress(g_hModKernel32, "Process32FirstW");
+    g_pfnProcess32NextW             = (PFNPROCESS32NEXTW          )GetProcAddress(g_hModKernel32, "Process32NextW");
+
+    /*
+     * psapi.dll APIs, if none of the above are available.
+     */
+    if (   !g_pfnCreateToolhelp32Snapshot
+        || !g_pfnProcess32FirstW
+        || !g_pfnProcess32NextW)
+    {
+        Assert(!g_pfnCreateToolhelp32Snapshot && !g_pfnProcess32FirstW && !g_pfnProcess32NextW);
+
+        rc = RTLdrLoadSystem("psapi.dll", true /*fNoUnload*/, &hMod);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTLdrGetSymbol(hMod, "GetModuleBaseNameW", (void **)&g_pfnGetModuleBaseNameW);
+            AssertStmt(RT_SUCCESS(rc), g_pfnGetModuleBaseNameW = NULL);
+
+            rc = RTLdrGetSymbol(hMod, "EnumProcesses", (void **)&g_pfnEnumProcesses);
+            AssertStmt(RT_SUCCESS(rc), g_pfnEnumProcesses = NULL);
+
+            RTLdrClose(hMod);
+        }
+    }
+
+    /*
+     * advapi32.dll APIs.
+     */
+    rc = RTLdrLoadSystem("advapi32.dll", true /*fNoUnload*/, &hMod);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTLdrGetSymbol(hMod, "CreateProcessWithLogonW", (void **)&g_pfnCreateProcessWithLogonW);
+        if (RT_FAILURE(rc)) { g_pfnCreateProcessWithLogonW = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT4); }
+
+        rc = RTLdrGetSymbol(hMod, "LogonUserW", (void **)&g_pfnLogonUserW);
+        if (RT_FAILURE(rc)) { g_pfnLogonUserW = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT350); }
+
+        rc = RTLdrGetSymbol(hMod, "CreateProcessAsUserW", (void **)&g_pfnCreateProcessAsUserW);
+        if (RT_FAILURE(rc)) { g_pfnCreateProcessAsUserW = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT350); }
+
+        RTLdrClose(hMod);
+    }
+
+    /*
+     * user32.dll APIs.
+     */
+    rc = RTLdrLoadSystem("user32.dll", true /*fNoUnload*/, &hMod);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTLdrGetSymbol(hMod, "OpenWindowStationW", (void **)&g_pfnOpenWindowStationW);
+        if (RT_FAILURE(rc)) { g_pfnOpenWindowStationW = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT310); }
+
+        rc = RTLdrGetSymbol(hMod, "CloseWindowStation", (void **)&g_pfnCloseWindowStation);
+        if (RT_FAILURE(rc)) { g_pfnCloseWindowStation = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT310); }
+
+        RTLdrClose(hMod);
+    }
+
+    /*
+     * userenv.dll APIs.
+     */
+    rc = RTLdrLoadSystem("userenv.dll", true /*fNoUnload*/, &hMod);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTLdrGetSymbol(hMod, "LoadUserProfileW", (void **)&g_pfnLoadUserProfileW);
+        if (RT_FAILURE(rc)) { g_pfnLoadUserProfileW = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT4); }
+
+        rc = RTLdrGetSymbol(hMod, "UnloadUserProfile", (void **)&g_pfnUnloadUserProfile);
+        if (RT_FAILURE(rc)) { g_pfnUnloadUserProfile = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT4); }
+
+        rc = RTLdrGetSymbol(hMod, "CreateEnvironmentBlock", (void **)&g_pfnCreateEnvironmentBlock);
+        if (RT_FAILURE(rc)) { g_pfnCreateEnvironmentBlock = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT4); }
+
+        rc = RTLdrGetSymbol(hMod, "DestroyEnvironmentBlock", (void **)&g_pfnDestroyEnvironmentBlock);
+        if (RT_FAILURE(rc)) { g_pfnDestroyEnvironmentBlock = NULL; Assert(g_enmWinVer <= kRTWinOSType_NT4); }
+
+        RTLdrClose(hMod);
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int) RTProcCreate(const char *pszExec, const char * const *papszArgs, RTENV Env, unsigned fFlags, PRTPROCESS pProcess)
+{
+    return RTProcCreateEx(pszExec, papszArgs, Env, fFlags,
+                          NULL, NULL, NULL,  /* standard handles */
+                          NULL /*pszAsUser*/, NULL /* pszPassword*/,
+                          NULL /*pvExtraData*/, pProcess);
+}
+
+
+/**
+ * The following NT call is for v3.51 and does the equivalent of:
+ *      DuplicateTokenEx(hSrcToken, MAXIMUM_ALLOWED, NULL,
+ *                       SecurityIdentification, TokenPrimary, phToken);
+ */
+static int rtProcWinDuplicateToken(HANDLE hSrcToken, PHANDLE phToken)
+{
+    int rc;
+    if (g_pfnNtDuplicateToken)
+    {
+        SECURITY_QUALITY_OF_SERVICE SecQoS;
+        SecQoS.Length              = sizeof(SecQoS);
+        SecQoS.ImpersonationLevel  = SecurityIdentification;
+        SecQoS.ContextTrackingMode = SECURITY_DYNAMIC_TRACKING;
+        SecQoS.EffectiveOnly       = FALSE;
+
+        OBJECT_ATTRIBUTES ObjAttr;
+        InitializeObjectAttributes(&ObjAttr, NULL /*Name*/, 0 /*OBJ_XXX*/, NULL /*Root*/, NULL /*SecDesc*/);
+        ObjAttr.SecurityQualityOfService = &SecQoS;
+
+        NTSTATUS rcNt = g_pfnNtDuplicateToken(hSrcToken, MAXIMUM_ALLOWED, &ObjAttr, FALSE, TokenPrimary, phToken);
+        if (NT_SUCCESS(rcNt))
+            rc = VINF_SUCCESS;
+        else
+            rc = RTErrConvertFromNtStatus(rcNt);
+    }
+    else
+        rc = VERR_SYMBOL_NOT_FOUND; /** @todo do we really need to duplicate the token? */
+    return rc;
+}
+
+
+/**
+ * Get the token assigned to the thread indicated by @a hThread.
+ *
+ * Only used when RTPROC_FLAGS_AS_IMPERSONATED_TOKEN is in effect and the
+ * purpose is to get a duplicate the impersonated token of the current thread.
+ *
+ * @returns IPRT status code.
+ * @param   hThread         The thread handle (current thread).
+ * @param   phToken         Where to return the a duplicate of the thread token
+ *                          handle on success. (The caller closes it.)
+ */
+static int rtProcWinGetThreadTokenHandle(HANDLE hThread, PHANDLE phToken)
+{
+    AssertPtr(phToken);
+
+    int     rc;
+    HANDLE hTokenThread;
+    if (OpenThreadToken(hThread,
+                        TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY | TOKEN_DUPLICATE
+                        | TOKEN_ASSIGN_PRIMARY | TOKEN_ADJUST_SESSIONID | TOKEN_READ | TOKEN_WRITE,
+                        TRUE /* OpenAsSelf - for impersonation at SecurityIdentification level */,
+                        &hTokenThread))
+    {
+        rc = rtProcWinDuplicateToken(hTokenThread, phToken);
+        CloseHandle(hTokenThread);
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+    return rc;
+}
+
+
+/**
+ * Get the token assigned the process indicated by @a hProcess.
+ *
+ * Only used when pwszUser is NULL and RTPROC_FLAGS_AS_IMPERSONATED_TOKEN isn't
+ * set.
+ *
+ * @returns IPRT status code.
+ * @param   hProcess        The process handle (current process).
+ * @param   phToken         Where to return the a duplicate of the thread token
+ *                          handle on success. (The caller closes it.)
+ */
+static int rtProcWinGetProcessTokenHandle(HANDLE hProcess, PHANDLE phToken)
+{
+    AssertPtr(phToken);
+
+    int     rc;
+    HANDLE hTokenProcess;
+    if (OpenProcessToken(hProcess,
+                         TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY | TOKEN_DUPLICATE
+                         | TOKEN_ASSIGN_PRIMARY | TOKEN_ADJUST_SESSIONID | TOKEN_READ | TOKEN_WRITE,
+                         &hTokenProcess))
+    {
+        rc = rtProcWinDuplicateToken(hTokenProcess, phToken); /* not sure if this is strictly necessary */
+        CloseHandle(hTokenProcess);
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+    return rc;
+}
+
+
+/**
+ * Get the process token of the process indicated by @a dwPID if the @a pSid and
+ * @a idSessionDesired matches.
+ *
+ * @returns IPRT status code.
+ * @param   dwPid               The process identifier.
+ * @param   pSid                The secure identifier of the user.
+ * @param   idDesiredSession    The session the process candidate should
+ *                              preferably belong to, UINT32_MAX if anything
+ *                              goes.
+ * @param   phToken             Where to return the a duplicate of the process token
+ *                              handle on success. (The caller closes it.)
+ */
+static int rtProcWinGetProcessTokenHandle(DWORD dwPid, PSID pSid, DWORD idDesiredSession, PHANDLE phToken)
+{
+    AssertPtr(pSid);
+    AssertPtr(phToken);
+
+    int     rc;
+    HANDLE  hProc = OpenProcess(MAXIMUM_ALLOWED, TRUE, dwPid);
+    if (hProc != NULL)
+    {
+        HANDLE hTokenProc;
+        if (OpenProcessToken(hProc,
+                             TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY | TOKEN_DUPLICATE | TOKEN_IMPERSONATE
+                             | TOKEN_ASSIGN_PRIMARY | TOKEN_ADJUST_SESSIONID | TOKEN_READ | TOKEN_WRITE,
+                             &hTokenProc))
+        {
+            /*
+             * Query the user SID from the token.
+             */
+            SetLastError(NO_ERROR);
+            DWORD   dwSize = 0;
+            BOOL    fRc    = GetTokenInformation(hTokenProc, TokenUser, NULL, 0, &dwSize);
+            DWORD   dwErr  = GetLastError();
+            if (   !fRc
+                && dwErr == ERROR_INSUFFICIENT_BUFFER
+                && dwSize > 0)
+            {
+                PTOKEN_USER pTokenUser = (PTOKEN_USER)RTMemTmpAllocZ(dwSize);
+                if (pTokenUser)
+                {
+                    if (GetTokenInformation(hTokenProc, TokenUser, pTokenUser, dwSize, &dwSize))
+                    {
+                        /*
+                         * Match token user with the user we're want to create a process as.
+                         */
+                        if (   IsValidSid(pTokenUser->User.Sid)
+                            && EqualSid(pTokenUser->User.Sid, pSid))
+                        {
+                            /*
+                             * Do we need to match the session ID?
+                             */
+                            rc = VINF_SUCCESS;
+                            if (idDesiredSession != UINT32_MAX)
+                            {
+                                DWORD idCurSession = UINT32_MAX;
+                                if (GetTokenInformation(hTokenProc, TokenSessionId, &idCurSession, sizeof(DWORD), &dwSize))
+                                    rc = idDesiredSession == idCurSession ? VINF_SUCCESS : VERR_NOT_FOUND;
+                                else
+                                    rc = RTErrConvertFromWin32(GetLastError());
+                            }
+                            if (RT_SUCCESS(rc))
+                            {
+                                /*
+                                 * Got a match.  Duplicate the token.  This duplicated token will
+                                 * be used for the actual CreateProcessAsUserW() call then.
+                                 */
+                                rc = rtProcWinDuplicateToken(hTokenProc, phToken);
+                            }
+                        }
+                        else
+                            rc = VERR_NOT_FOUND;
+                    }
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                    RTMemTmpFree(pTokenUser);
+                }
+                else
+                    rc = VERR_NO_MEMORY;
+            }
+            else if (fRc || dwErr == NO_ERROR)
+                rc = VERR_IPE_UNEXPECTED_STATUS;
+            else
+                rc = RTErrConvertFromWin32(dwErr);
+            CloseHandle(hTokenProc);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        CloseHandle(hProc);
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+    return rc;
+}
+
+
+/**
+ * Fallback method for rtProcWinFindTokenByProcess that uses the older NT4
+ * PSAPI.DLL API.
+ *
+ * @returns Success indicator.
+ * @param   papszNames      The process candidates, in prioritized order.
+ * @param   pSid            The secure identifier of the user.
+ * @param   phToken         Where to return the token handle - duplicate,
+ *                          caller closes it on success.
+ *
+ * @remarks NT4 needs a copy of "PSAPI.dll" (redistributed by Microsoft and not
+ *          part of the OS) in order to get a lookup.  If we don't have this DLL
+ *          we are not able to get a token and therefore no UI will be visible.
+ */
+static bool rtProcWinFindTokenByProcessAndPsApi(const char * const *papszNames, PSID pSid, PHANDLE phToken)
+{
+    /*
+     * Load PSAPI.DLL and resolve the two symbols we need.
+     */
+    if (   !g_pfnGetModuleBaseNameW
+        || !g_pfnEnumProcesses)
+        return false;
+
+    /*
+     * Get a list of PID.  We retry if it looks like there are more PIDs
+     * to be returned than what we supplied buffer space for.
+     */
+    bool   fFound          = false;
+    int    rc              = VINF_SUCCESS;
+    DWORD  cbPidsAllocated = 4096;
+    DWORD  cbPidsReturned  = 0; /* (MSC maybe used uninitialized) */
+    DWORD *paPids;
+    for (;;)
+    {
+        paPids = (DWORD *)RTMemTmpAlloc(cbPidsAllocated);
+        AssertBreakStmt(paPids, rc = VERR_NO_TMP_MEMORY);
+        cbPidsReturned = 0;
+        if (!g_pfnEnumProcesses(paPids, cbPidsAllocated, &cbPidsReturned))
+        {
+            rc = RTErrConvertFromWin32(GetLastError());
+            AssertMsgFailedBreak(("%Rrc\n", rc));
+        }
+        if (   cbPidsReturned < cbPidsAllocated
+            || cbPidsAllocated >= _512K)
+            break;
+        RTMemTmpFree(paPids);
+        cbPidsAllocated *= 2;
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Search for the process.
+         *
+         * We ASSUME that the caller won't be specifying any names longer
+         * than RTPATH_MAX.
+         */
+        PRTUTF16 pwszProcName = (PRTUTF16)RTMemTmpAllocZ(RTPATH_MAX * sizeof(pwszProcName[0]));
+        if (pwszProcName)
+        {
+            for (size_t i = 0; papszNames[i] && !fFound; i++)
+            {
+                const DWORD cPids = cbPidsReturned / sizeof(DWORD);
+                for (DWORD iPid = 0; iPid < cPids && !fFound; iPid++)
+                {
+                    HANDLE hProc = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, paPids[iPid]);
+                    if (hProc)
+                    {
+                        *pwszProcName = '\0';
+                        DWORD cbRet = g_pfnGetModuleBaseNameW(hProc, 0 /*hModule = exe */, pwszProcName, RTPATH_MAX);
+                        if (   cbRet > 0
+                            && RTUtf16ICmpAscii(pwszProcName, papszNames[i]) == 0
+                            && RT_SUCCESS(rtProcWinGetProcessTokenHandle(paPids[iPid], pSid, UINT32_MAX, phToken)))
+                            fFound = true;
+                        CloseHandle(hProc);
+                    }
+                }
+            }
+            RTMemTmpFree(pwszProcName);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+    }
+    RTMemTmpFree(paPids);
+
+    return fFound;
+}
+
+
+/**
+ * Finds a one of the processes in @a papszNames running with user @a pSid and possibly
+ * in the required windows session. Returns a duplicate handle to its token.
+ *
+ * @returns Success indicator.
+ * @param   papszNames          The process candidates, in prioritized order.
+ * @param   pSid                The secure identifier of the user.
+ * @param   idDesiredSession    The session the process candidate should
+ *                              belong to if possible, UINT32_MAX if anything
+ *                              goes.
+ * @param   phToken             Where to return the token handle - duplicate,
+ *                              caller closes it on success.
+ */
+static bool rtProcWinFindTokenByProcess(const char * const *papszNames, PSID pSid, uint32_t idDesiredSession, PHANDLE phToken)
+{
+    AssertPtr(papszNames);
+    AssertPtr(pSid);
+    AssertPtr(phToken);
+
+    bool fFound = false;
+
+    /*
+     * On modern systems (W2K+) try the Toolhelp32 API first; this is more stable
+     * and reliable.  Fallback to EnumProcess on NT4.
+     */
+    bool fFallback = true;
+    if (g_pfnProcess32NextW && g_pfnProcess32FirstW && g_pfnCreateToolhelp32Snapshot)
+    {
+        HANDLE hSnap = g_pfnCreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+        Assert(hSnap != INVALID_HANDLE_VALUE);
+        if (hSnap != INVALID_HANDLE_VALUE)
+        {
+            fFallback = false;
+            for (size_t i = 0; papszNames[i] && !fFound; i++)
+            {
+                PROCESSENTRY32W ProcEntry;
+                ProcEntry.dwSize = sizeof(PROCESSENTRY32);
+                ProcEntry.szExeFile[0] = '\0';
+                if (g_pfnProcess32FirstW(hSnap, &ProcEntry))
+                {
+                    do
+                    {
+                        if (RTUtf16ICmpAscii(ProcEntry.szExeFile, papszNames[i]) == 0)
+                        {
+                            int rc = rtProcWinGetProcessTokenHandle(ProcEntry.th32ProcessID, pSid, idDesiredSession, phToken);
+                            if (RT_SUCCESS(rc))
+                            {
+                                fFound = true;
+                                break;
+                            }
+                        }
+                    } while (g_pfnProcess32NextW(hSnap, &ProcEntry));
+                }
+                else
+                    AssertMsgFailed(("dwErr=%u (%x)\n", GetLastError(), GetLastError()));
+            }
+            CloseHandle(hSnap);
+        }
+    }
+
+    /* If we couldn't take a process snapshot for some reason or another, fall
+       back on the NT4 compatible API. */
+    if (fFallback)
+        fFound = rtProcWinFindTokenByProcessAndPsApi(papszNames, pSid, phToken);
+    return fFound;
+}
+
+
+/**
+ * Logs on a specified user and returns its primary token.
+ *
+ * @returns IPRT status code.
+ * @param   pwszUser            User name. A domain name can be specified (as part of a UPN, User Principal Name),
+ *                              e.g. "joedoe@example.com".
+ * @param   pwszPassword        Password.
+ * @param   phToken             Pointer to store the logon token.
+ */
+static int rtProcWinUserLogon(PRTUTF16 pwszUser, PRTUTF16 pwszPassword, HANDLE *phToken)
+{
+    AssertPtrReturn(pwszUser,     VERR_INVALID_POINTER);
+    AssertPtrReturn(pwszPassword, VERR_INVALID_POINTER);
+    AssertPtrReturn(phToken,      VERR_INVALID_POINTER);
+    if (!g_pfnLogonUserW)
+        return VERR_NOT_SUPPORTED;
+
+    /*
+     * Because we have to deal with http://support.microsoft.com/kb/245683
+     * for NULL domain names when running on NT4 here, pass an empty string if so.
+     * However, passing FQDNs should work!
+     *
+     * The SE_TCB_NAME (Policy: Act as part of the operating system) right
+     * is required on older windows versions (NT4, W2K, possibly XP).
+     */
+    PCRTUTF16 pwszDomainNone = g_enmWinVer < kRTWinOSType_2K ? L"" /* NT4 and older */ : NULL /* Windows 2000 and up */;
+    BOOL fRc = g_pfnLogonUserW(pwszUser,
+                               /* The domain always is passed as part of the UPN (user name). */
+                               pwszDomainNone,
+                               pwszPassword,
+                               LOGON32_LOGON_INTERACTIVE,
+                               LOGON32_PROVIDER_DEFAULT,
+                               phToken);
+    if (fRc)
+        return VINF_SUCCESS;
+
+    DWORD dwErr = GetLastError();
+    int rc = dwErr == ERROR_PRIVILEGE_NOT_HELD ? VERR_PROC_TCB_PRIV_NOT_HELD : RTErrConvertFromWin32(dwErr);
+    if (rc == VERR_UNRESOLVED_ERROR)
+        LogRelFunc(("dwErr=%u (%#x), rc=%Rrc\n", dwErr, dwErr, rc));
+    return rc;
+}
+
+
+/**
+ * Returns the environment to use for the child process.
+ *
+ * This implements the RTPROC_FLAGS_ENV_CHANGE_RECORD and environment related
+ * parts of RTPROC_FLAGS_PROFILE.
+ *
+ * @returns IPRT status code.
+ * @param   hToken      The user token to use if RTPROC_FLAGS_PROFILE is given.
+ *                      The caller must have loaded profile for this.
+ * @param   hEnv        The environment passed in by the RTProcCreateEx caller.
+ * @param   fFlags      The process creation flags passed in by the
+ *                      RTProcCreateEx caller (RTPROC_FLAGS_XXX).
+ * @param   phEnv       Where to return the environment to use.  This can either
+ *                      be a newly created environment block or @a hEnv.  In the
+ *                      former case, the caller must destroy it.
+ */
+static int rtProcWinCreateEnvFromToken(HANDLE hToken, RTENV hEnv, uint32_t fFlags, PRTENV phEnv)
+{
+    int rc;
+
+    /*
+     * Query the environment from the user profile associated with the token if
+     * the caller has specified it directly or indirectly.
+     */
+    if (   (fFlags & RTPROC_FLAGS_PROFILE)
+        && (   hEnv == RTENV_DEFAULT
+            || (fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)) )
+    {
+        if (g_pfnCreateEnvironmentBlock && g_pfnDestroyEnvironmentBlock)
+        {
+            LPVOID pvEnvBlockProfile = NULL;
+            if (g_pfnCreateEnvironmentBlock(&pvEnvBlockProfile, hToken, FALSE /* Don't inherit from parent. */))
+            {
+                rc = RTEnvCloneUtf16Block(phEnv, (PCRTUTF16)pvEnvBlockProfile, 0 /*fFlags*/);
+                if (   (fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)
+                    && RT_SUCCESS(rc)
+                    && hEnv != RTENV_DEFAULT)
+                {
+                    rc = RTEnvApplyChanges(*phEnv, hEnv);
+                    if (RT_FAILURE(rc))
+                        RTEnvDestroy(*phEnv);
+                }
+                g_pfnDestroyEnvironmentBlock(pvEnvBlockProfile);
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else
+            rc = VERR_SYMBOL_NOT_FOUND;
+    }
+    /*
+     * We we've got an incoming change record, combine it with the default environment.
+     */
+    else if (hEnv != RTENV_DEFAULT && (fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD))
+    {
+        rc = RTEnvClone(phEnv, RTENV_DEFAULT);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTEnvApplyChanges(*phEnv, hEnv);
+            if (RT_FAILURE(rc))
+                RTEnvDestroy(*phEnv);
+        }
+    }
+    /*
+     * Otherwise we can return the incoming environment directly.
+     */
+    else
+    {
+        *phEnv = hEnv;
+        rc = VINF_SUCCESS;
+    }
+
+    return rc;
+}
+
+
+/**
+ * Figures which privilege we're missing for success application of
+ * CreateProcessAsUserW.
+ *
+ * @returns IPRT error status.
+ */
+static int rtProcWinFigureWhichPrivilegeNotHeld2(void)
+{
+    HANDLE hToken;
+    if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES, &hToken))
+    {
+        static struct
+        {
+            const char *pszName;
+            int         rc;
+        } const s_aPrivileges[] =
+        {
+            { SE_TCB_NAME,                      VERR_PROC_TCB_PRIV_NOT_HELD },
+            { SE_ASSIGNPRIMARYTOKEN_NAME,       VERR_PROC_APT_PRIV_NOT_HELD },
+            { SE_INCREASE_QUOTA_NAME,           VERR_PROC_IQ_PRIV_NOT_HELD  },
+        };
+        for (uint32_t i = 0; i < RT_ELEMENTS(s_aPrivileges); i++)
+        {
+            union
+            {
+                TOKEN_PRIVILEGES TokPriv;
+                char abAlloced[sizeof(TOKEN_PRIVILEGES) + sizeof(LUID_AND_ATTRIBUTES)];
+            } uNew, uOld;
+            uNew.TokPriv.PrivilegeCount = 1;
+            uNew.TokPriv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+            AssertContinue(LookupPrivilegeValue(NULL, s_aPrivileges[i].pszName, &uNew.TokPriv.Privileges[0].Luid));
+            uOld = uNew;
+            SetLastError(NO_ERROR);
+            DWORD cbActual = RT_UOFFSETOF(TOKEN_PRIVILEGES, Privileges[1]);
+            AdjustTokenPrivileges(hToken, FALSE /*fDisableAllPrivileges*/, &uNew.TokPriv, cbActual, &uOld.TokPriv, &cbActual);
+            if (GetLastError() != NO_ERROR)
+            {
+                CloseHandle(hToken);
+                return s_aPrivileges[i].rc;
+            }
+            if (uOld.TokPriv.Privileges[0].Attributes == 0)
+                AdjustTokenPrivileges(hToken, FALSE /*fDisableAllPrivileges*/, &uOld.TokPriv, 0, NULL, NULL);
+        }
+        AssertFailed();
+        CloseHandle(hToken);
+    }
+    else
+        AssertFailed();
+    return VERR_PRIVILEGE_NOT_HELD;
+}
+
+#if 0 /* debug code */
+
+static char *rtProcWinSidToString(char *psz, PSID pSid)
+{
+     char *pszRet = psz;
+
+     *psz++ = 'S';
+     *psz++ = '-';
+     *psz++ = '1';
+     *psz++ = '-';
+
+     PISID pISid = (PISID)pSid;
+
+     psz += RTStrFormatU32(psz, 32, RT_MAKE_U32_FROM_U8(pISid->IdentifierAuthority.Value[5],
+                                                        pISid->IdentifierAuthority.Value[4],
+                                                        pISid->IdentifierAuthority.Value[3],
+                                                        pISid->IdentifierAuthority.Value[2]),
+                           10, 0, 0, 0);
+     for (unsigned i = 0; i < pISid->SubAuthorityCount; i++)
+     {
+          *psz++ = '-';
+          psz += RTStrFormatU32(psz, 32, pISid->SubAuthority[i], 10, 0, 0, 0);
+     }
+     *psz++ = '\0';
+     return pszRet;
+}
+
+static void rtProcWinLogAcl(PACL pAcl)
+{
+    if (!pAcl)
+        RTAssertMsg2("ACL is NULL\n");
+    else
+    {
+        RTAssertMsg2("AceCount=%d AclSize=%#x AclRevision=%d\n", pAcl->AceCount, pAcl->AclSize, pAcl->AclRevision);
+        for (uint32_t i = 0; i < pAcl->AceCount; i++)
+        {
+            PACE_HEADER pAceHdr = NULL;
+            if (GetAce(pAcl, i, (PVOID *)&pAceHdr))
+            {
+                RTAssertMsg2(" ACE[%u]: Flags=%#x Type=%#x Size=%#x", i, pAceHdr->AceFlags, pAceHdr->AceType, pAceHdr->AceSize);
+                char szTmp[256];
+                if (pAceHdr->AceType == ACCESS_ALLOWED_ACE_TYPE)
+                    RTAssertMsg2(" Mask=%#x %s\n", ((ACCESS_ALLOWED_ACE *)pAceHdr)->Mask,
+                                 rtProcWinSidToString(szTmp, &((ACCESS_ALLOWED_ACE *)pAceHdr)->SidStart));
+                else
+                    RTAssertMsg2(" ACE[%u]: Flags=%#x Type=%#x Size=%#x\n", i, pAceHdr->AceFlags, pAceHdr->AceType, pAceHdr->AceSize);
+            }
+        }
+    }
+}
+
+static bool rtProcWinLogSecAttr(HANDLE hUserObj)
+{
+    /*
+     * Get the security descriptor for the user interface object.
+     */
+    uint32_t             cbSecDesc = _64K;
+    PSECURITY_DESCRIPTOR pSecDesc  = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+    SECURITY_INFORMATION SecInfo   = DACL_SECURITY_INFORMATION;
+    DWORD                cbNeeded;
+    AssertReturn(pSecDesc, false);
+    if (!GetUserObjectSecurity(hUserObj, &SecInfo, pSecDesc, cbSecDesc, &cbNeeded))
+    {
+        RTMemTmpFree(pSecDesc);
+        AssertReturn(GetLastError() == ERROR_INSUFFICIENT_BUFFER, false);
+        cbSecDesc = cbNeeded + 128;
+        pSecDesc  = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+        AssertReturn(pSecDesc, false);
+        if (!GetUserObjectSecurity(hUserObj, &SecInfo, pSecDesc, cbSecDesc, &cbNeeded))
+        {
+            RTMemTmpFree(pSecDesc);
+            AssertFailedReturn(false);
+        }
+    }
+
+    /*
+     * Get the discretionary access control list (if we have one).
+     */
+    BOOL fDaclDefaulted;
+    BOOL fDaclPresent;
+    PACL pDacl;
+    if (GetSecurityDescriptorDacl(pSecDesc, &fDaclPresent, &pDacl, &fDaclDefaulted))
+        rtProcWinLogAcl(pDacl);
+    else
+        RTAssertMsg2("GetSecurityDescriptorDacl failed\n");
+
+    RTMemFree(pSecDesc);
+    return true;
+}
+
+#endif /* debug */
+
+/**
+ * Get the user SID from a token.
+ *
+ * @returns Pointer to the SID on success. Free by calling RTMemFree.
+ * @param   hToken              The token..
+ * @param   prc                 Optional return code.
+ */
+static PSID rtProcWinGetTokenUserSid(HANDLE hToken, int *prc)
+{
+    int rcIgn;
+    if (!prc)
+        prc = &rcIgn;
+    *prc = VERR_NO_MEMORY;
+
+    /*
+     * Get the groups associated with the token.  We just try a size first then
+     * reallocates if it's insufficient.
+     */
+    DWORD       cbUser = _1K;
+    PTOKEN_USER pUser  = (PTOKEN_USER)RTMemTmpAlloc(cbUser);
+    AssertReturn(pUser, NULL);
+    DWORD cbNeeded = 0;
+    if (!GetTokenInformation(hToken, TokenUser, pUser, cbUser, &cbNeeded))
+    {
+        DWORD dwErr = GetLastError();
+        RTMemTmpFree(pUser);
+        AssertLogRelMsgReturnStmt(dwErr == ERROR_INSUFFICIENT_BUFFER,
+                                  ("rtProcWinGetTokenUserSid: GetTokenInformation failed with %u\n", dwErr),
+                                  *prc = RTErrConvertFromWin32(dwErr), NULL);
+        cbUser = cbNeeded + 128;
+        pUser = (PTOKEN_USER)RTMemTmpAlloc(cbUser);
+        AssertReturn(pUser, NULL);
+        if (!GetTokenInformation(hToken, TokenUser, pUser, cbUser, &cbNeeded))
+        {
+            dwErr = GetLastError();
+            *prc = RTErrConvertFromWin32(dwErr);
+            RTMemTmpFree(pUser);
+            AssertLogRelMsgFailedReturn(("rtProcWinGetTokenUserSid: GetTokenInformation failed with %u\n", dwErr), NULL);
+        }
+    }
+
+    DWORD cbSid = GetLengthSid(pUser->User.Sid);
+    PSID pSidRet = RTMemDup(pUser->User.Sid, cbSid);
+    Assert(pSidRet);
+    RTMemTmpFree(pUser);
+    *prc = VINF_SUCCESS;
+    return pSidRet;
+}
+
+
+#if 0 /* not used */
+/**
+ * Get the login SID from a token.
+ *
+ * @returns Pointer to the SID on success. Free by calling RTMemFree.
+ * @param   hToken              The token..
+ */
+static PSID rtProcWinGetTokenLogonSid(HANDLE hToken)
+{
+    /*
+     * Get the groups associated with the token.  We just try a size first then
+     * reallocates if it's insufficient.
+     */
+    DWORD         cbGroups = _1K;
+    PTOKEN_GROUPS pGroups = (PTOKEN_GROUPS)RTMemTmpAlloc(cbGroups);
+    AssertReturn(pGroups, NULL);
+    DWORD cbNeeded = 0;
+    if (!GetTokenInformation(hToken, TokenGroups, pGroups, cbGroups, &cbNeeded))
+    {
+        RTMemTmpFree(pGroups);
+        AssertReturn(GetLastError() == ERROR_INSUFFICIENT_BUFFER, NULL);
+        cbGroups = cbNeeded + 128;
+        pGroups = (PTOKEN_GROUPS)RTMemTmpAlloc(cbGroups);
+        AssertReturn(pGroups, NULL);
+        if (!GetTokenInformation(hToken, TokenGroups, pGroups, cbGroups, &cbNeeded))
+        {
+            RTMemTmpFree(pGroups);
+            AssertFailedReturn(NULL);
+        }
+    }
+
+    /*
+     * Locate the logon sid.
+     */
+    PSID     pSidRet = NULL;
+    uint32_t i = pGroups->GroupCount;
+    while (i-- > 0)
+        if ((pGroups->Groups[i].Attributes & SE_GROUP_LOGON_ID) == SE_GROUP_LOGON_ID)
+        {
+            DWORD cbSid = GetLengthSid(pGroups->Groups[i].Sid);
+            pSidRet = RTMemDup(pGroups->Groups[i].Sid, cbSid);
+            break;
+        }
+
+    RTMemTmpFree(pGroups);
+    Assert(pSidRet);
+    return pSidRet;
+}
+#endif /* unused */
+
+
+/**
+ * Retrieves the DACL security descriptor of the give GUI object.
+ *
+ * @returns Pointer to the security descriptor.
+ * @param   hUserObj        The GUI object handle.
+ * @param   pcbSecDesc      Where to return the size of the security descriptor.
+ * @param   ppDacl          Where to return the DACL pointer.
+ * @param   pfDaclPresent   Where to return the DACL-present indicator.
+ * @param   pDaclSizeInfo   Where to return the DACL size information.
+ */
+static PSECURITY_DESCRIPTOR rtProcWinGetUserObjDacl(HANDLE hUserObj, uint32_t *pcbSecDesc, PACL *ppDacl,
+                                                    BOOL *pfDaclPresent, ACL_SIZE_INFORMATION *pDaclSizeInfo)
+{
+    /*
+     * Get the security descriptor for the user interface object.
+     */
+    uint32_t             cbSecDesc = _1K;
+    PSECURITY_DESCRIPTOR pSecDesc  = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+    SECURITY_INFORMATION SecInfo   = DACL_SECURITY_INFORMATION;
+    DWORD                cbNeeded;
+    AssertReturn(pSecDesc, NULL);
+    if (!GetUserObjectSecurity(hUserObj, &SecInfo, pSecDesc, cbSecDesc, &cbNeeded))
+    {
+        RTMemTmpFree(pSecDesc);
+        AssertReturn(GetLastError() == ERROR_INSUFFICIENT_BUFFER, NULL);
+        cbSecDesc = cbNeeded + 128;
+        pSecDesc  = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+        AssertReturn(pSecDesc, NULL);
+        if (!GetUserObjectSecurity(hUserObj, &SecInfo, pSecDesc, cbSecDesc, &cbNeeded))
+        {
+            RTMemTmpFree(pSecDesc);
+            AssertFailedReturn(NULL);
+        }
+    }
+    *pcbSecDesc = cbNeeded;
+
+    /*
+     * Get the discretionary access control list (if we have one).
+     */
+    BOOL fDaclDefaulted;
+    if (GetSecurityDescriptorDacl(pSecDesc, pfDaclPresent, ppDacl, &fDaclDefaulted))
+    {
+        RT_ZERO(*pDaclSizeInfo);
+        pDaclSizeInfo->AclBytesInUse = sizeof(ACL);
+        if (   !*ppDacl
+            || GetAclInformation(*ppDacl, pDaclSizeInfo, sizeof(*pDaclSizeInfo), AclSizeInformation))
+            return pSecDesc;
+        AssertFailed();
+    }
+    else
+        AssertFailed();
+    RTMemTmpFree(pSecDesc);
+    return NULL;
+}
+
+
+/**
+ * Copy ACEs from one ACL to another.
+ *
+ * @returns true on success, false on failure.
+ * @param   pDst                The destination ACL.
+ * @param   pSrc                The source ACL.
+ * @param   cAces               The number of ACEs to copy.
+ */
+static bool rtProcWinCopyAces(PACL pDst, PACL pSrc, uint32_t cAces)
+{
+    for (uint32_t i = 0; i < cAces; i++)
+    {
+        PACE_HEADER pAceHdr;
+        AssertReturn(GetAce(pSrc, i, (PVOID *)&pAceHdr), false);
+        AssertReturn(AddAce(pDst, ACL_REVISION, MAXDWORD, pAceHdr, pAceHdr->AceSize), false);
+    }
+    return true;
+}
+
+
+/**
+ * Adds an access-allowed access control entry to an ACL.
+ *
+ * @returns true on success, false on failure.
+ * @param   pDstAcl             The ACL.
+ * @param   fAceFlags           The ACE flags.
+ * @param   fMask               The ACE access mask.
+ * @param   pSid                The SID to go with the ACE.
+ * @param   cbSid               The size of the SID.
+ */
+static bool rtProcWinAddAccessAllowedAce(PACL pDstAcl, uint32_t fAceFlags, uint32_t fMask, PSID pSid, uint32_t cbSid)
+{
+    struct
+    {
+        ACCESS_ALLOWED_ACE  Core;
+        DWORD               abPadding[128]; /* More than enough, AFAIK. */
+    } AceBuf;
+    RT_ZERO(AceBuf);
+    uint32_t const cbAllowedAce = RT_UOFFSETOF(ACCESS_ALLOWED_ACE, SidStart) + cbSid;
+    AssertReturn(cbAllowedAce <= sizeof(AceBuf), false);
+
+    AceBuf.Core.Header.AceSize     = cbAllowedAce;
+    AceBuf.Core.Header.AceType     = ACCESS_ALLOWED_ACE_TYPE;
+    AceBuf.Core.Header.AceFlags    = fAceFlags;
+    AceBuf.Core.Mask               = fMask;
+    AssertReturn(CopySid(cbSid, &AceBuf.Core.SidStart, pSid), false);
+
+    uint32_t i = pDstAcl->AceCount;
+    while (i-- > 0)
+    {
+        PACE_HEADER pAceHdr;
+        AssertContinue(GetAce(pDstAcl, i, (PVOID *)&pAceHdr));
+        if (   pAceHdr->AceSize == cbAllowedAce
+            && memcmp(pAceHdr, &AceBuf.Core, cbAllowedAce) == 0)
+            return true;
+
+    }
+    AssertMsgReturn(AddAce(pDstAcl, ACL_REVISION, MAXDWORD, &AceBuf.Core, cbAllowedAce), ("%u\n", GetLastError()), false);
+    return true;
+}
+
+
+/** All window station rights we know about   */
+#define MY_WINSTATION_ALL_RIGHTS (  WINSTA_ACCESSCLIPBOARD | WINSTA_ACCESSGLOBALATOMS | WINSTA_CREATEDESKTOP \
+                                  | WINSTA_ENUMDESKTOPS | WINSTA_ENUMERATE | WINSTA_EXITWINDOWS | WINSTA_READATTRIBUTES \
+                                  | WINSTA_READSCREEN | WINSTA_WRITEATTRIBUTES | DELETE | READ_CONTROL | WRITE_DAC | WRITE_OWNER )
+/** All desktop rights we know about   */
+#define MY_DESKTOP_ALL_RIGHTS    (  DESKTOP_CREATEMENU | DESKTOP_CREATEWINDOW | DESKTOP_ENUMERATE | DESKTOP_HOOKCONTROL \
+                                  | DESKTOP_JOURNALPLAYBACK | DESKTOP_JOURNALRECORD | DESKTOP_READOBJECTS \
+                                  | DESKTOP_SWITCHDESKTOP | DESKTOP_WRITEOBJECTS | DELETE | READ_CONTROL | WRITE_DAC \
+                                  | WRITE_OWNER )
+/** Generic rights. */
+#define MY_GENERIC_ALL_RIGHTS    ( GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL )
+
+
+/**
+ * Grants the given SID full access to the given window station.
+ *
+ * @returns true on success, false on failure.
+ * @param   hWinStation         The window station.
+ * @param   pSid                The SID.
+ */
+static bool rtProcWinAddSidToWinStation(HWINSTA hWinStation, PSID pSid)
+{
+    bool fRet = false;
+
+    /*
+     * Get the current DACL.
+     */
+    uint32_t                cbSecDesc;
+    PACL                    pDacl;
+    ACL_SIZE_INFORMATION    DaclSizeInfo;
+    BOOL                    fDaclPresent;
+    PSECURITY_DESCRIPTOR    pSecDesc = rtProcWinGetUserObjDacl(hWinStation, &cbSecDesc, &pDacl, &fDaclPresent, &DaclSizeInfo);
+    if (pSecDesc)
+    {
+        /*
+         * Create a new DACL. This will contain two extra ACEs.
+         */
+        PSECURITY_DESCRIPTOR pNewSecDesc = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+        if (   pNewSecDesc
+            && InitializeSecurityDescriptor(pNewSecDesc, SECURITY_DESCRIPTOR_REVISION))
+        {
+            uint32_t const cbSid     = GetLengthSid(pSid);
+            uint32_t const cbNewDacl = DaclSizeInfo.AclBytesInUse + (sizeof(ACCESS_ALLOWED_ACE) + cbSid) * 2;
+            PACL pNewDacl = (PACL)RTMemTmpAlloc(cbNewDacl);
+            if (   pNewDacl
+                && InitializeAcl(pNewDacl, cbNewDacl, ACL_REVISION)
+                && rtProcWinCopyAces(pNewDacl, pDacl, fDaclPresent ? DaclSizeInfo.AceCount : 0))
+            {
+                /*
+                 * Add the two new SID ACEs.
+                 */
+                if (   rtProcWinAddAccessAllowedAce(pNewDacl, CONTAINER_INHERIT_ACE | INHERIT_ONLY_ACE | OBJECT_INHERIT_ACE,
+                                                    MY_GENERIC_ALL_RIGHTS, pSid, cbSid)
+                    && rtProcWinAddAccessAllowedAce(pNewDacl, NO_PROPAGATE_INHERIT_ACE, MY_WINSTATION_ALL_RIGHTS, pSid, cbSid))
+                {
+                    /*
+                     * Now mate the new DECL with the security descriptor and set it.
+                     */
+                    if (SetSecurityDescriptorDacl(pNewSecDesc, TRUE /*fDaclPresent*/, pNewDacl, FALSE /*fDaclDefaulted*/))
+                    {
+                        SECURITY_INFORMATION SecInfo = DACL_SECURITY_INFORMATION;
+                        if (SetUserObjectSecurity(hWinStation, &SecInfo, pNewSecDesc))
+                            fRet = true;
+                        else
+                            AssertFailed();
+                    }
+                    else
+                        AssertFailed();
+                }
+                else
+                    AssertFailed();
+            }
+            else
+                AssertFailed();
+            RTMemTmpFree(pNewDacl);
+        }
+        else
+            AssertFailed();
+        RTMemTmpFree(pNewSecDesc);
+        RTMemTmpFree(pSecDesc);
+    }
+    return fRet;
+}
+
+
+/**
+ * Grants the given SID full access to the given desktop.
+ *
+ * @returns true on success, false on failure.
+ * @param   hDesktop            The desktop handle.
+ * @param   pSid                The SID.
+ */
+static bool rtProcWinAddSidToDesktop(HDESK hDesktop, PSID pSid)
+{
+    bool fRet = false;
+
+    /*
+     * Get the current DACL.
+     */
+    uint32_t                cbSecDesc;
+    PACL                    pDacl;
+    ACL_SIZE_INFORMATION    DaclSizeInfo;
+    BOOL                    fDaclPresent;
+    PSECURITY_DESCRIPTOR    pSecDesc = rtProcWinGetUserObjDacl(hDesktop, &cbSecDesc, &pDacl, &fDaclPresent, &DaclSizeInfo);
+    if (pSecDesc)
+    {
+        /*
+         * Create a new DACL. This will contain one extra ACE.
+         */
+        PSECURITY_DESCRIPTOR pNewSecDesc = (PSECURITY_DESCRIPTOR)RTMemTmpAlloc(cbSecDesc);
+        if (   pNewSecDesc
+            && InitializeSecurityDescriptor(pNewSecDesc, SECURITY_DESCRIPTOR_REVISION))
+        {
+            uint32_t const cbSid     = GetLengthSid(pSid);
+            uint32_t const cbNewDacl = DaclSizeInfo.AclBytesInUse + (sizeof(ACCESS_ALLOWED_ACE) + cbSid) * 1;
+            PACL pNewDacl = (PACL)RTMemTmpAlloc(cbNewDacl);
+            if (   pNewDacl
+                && InitializeAcl(pNewDacl, cbNewDacl, ACL_REVISION)
+                && rtProcWinCopyAces(pNewDacl, pDacl, fDaclPresent ? DaclSizeInfo.AceCount : 0))
+            {
+                /*
+                 * Add the new SID ACE.
+                 */
+                if (rtProcWinAddAccessAllowedAce(pNewDacl, 0 /*fAceFlags*/, MY_DESKTOP_ALL_RIGHTS, pSid, cbSid))
+                {
+                    /*
+                     * Now mate the new DECL with the security descriptor and set it.
+                     */
+                    if (SetSecurityDescriptorDacl(pNewSecDesc, TRUE /*fDaclPresent*/, pNewDacl, FALSE /*fDaclDefaulted*/))
+                    {
+                        SECURITY_INFORMATION SecInfo = DACL_SECURITY_INFORMATION;
+                        if (SetUserObjectSecurity(hDesktop, &SecInfo, pNewSecDesc))
+                            fRet = true;
+                        else
+                            AssertFailed();
+                    }
+                    else
+                        AssertFailed();
+                }
+                else
+                    AssertFailed();
+            }
+            else
+                AssertFailed();
+            RTMemTmpFree(pNewDacl);
+        }
+        else
+            AssertFailed();
+        RTMemTmpFree(pNewSecDesc);
+        RTMemTmpFree(pSecDesc);
+    }
+    return fRet;
+}
+
+
+/**
+ * Preps the window station and desktop for the new app.
+ *
+ * EXPERIMENTAL. Thus no return code.
+ *
+ * @param   hTokenToUse     The access token of the new process.
+ * @param   pStartupInfo    The startup info (we'll change lpDesktop, maybe).
+ * @param   phWinStationOld Where to return an window station handle to restore.
+ *                          Pass this to SetProcessWindowStation if not NULL.
+ */
+static void rtProcWinStationPrep(HANDLE hTokenToUse, STARTUPINFOW *pStartupInfo, HWINSTA *phWinStationOld)
+{
+    /** @todo Always mess with the interactive one? Maybe it's not there...  */
+    *phWinStationOld = GetProcessWindowStation();
+    HWINSTA hWinStation0;
+    if (g_pfnOpenWindowStationW)
+        hWinStation0 = g_pfnOpenWindowStationW(L"winsta0", FALSE /*fInherit*/, READ_CONTROL | WRITE_DAC);
+    else
+        hWinStation0 = OpenWindowStationA("winsta0", FALSE /*fInherit*/, READ_CONTROL | WRITE_DAC); /* (for NT3.1) */
+    if (hWinStation0)
+    {
+        if (SetProcessWindowStation(hWinStation0))
+        {
+            HDESK hDesktop = OpenDesktop("default", 0 /*fFlags*/, FALSE /*fInherit*/,
+                                         READ_CONTROL | WRITE_DAC | DESKTOP_WRITEOBJECTS | DESKTOP_READOBJECTS);
+            if (hDesktop)
+            {
+                /*PSID pSid = rtProcWinGetTokenLogonSid(hTokenToUse); - Better to use the user SID. Avoid overflowing the ACL. */
+                PSID pSid = rtProcWinGetTokenUserSid(hTokenToUse, NULL /*prc*/);
+                if (pSid)
+                {
+                    if (   rtProcWinAddSidToWinStation(hWinStation0, pSid)
+                        && rtProcWinAddSidToDesktop(hDesktop, pSid))
+                    {
+                        pStartupInfo->lpDesktop = L"winsta0\\default";
+                    }
+                    RTMemFree(pSid);
+                }
+                CloseDesktop(hDesktop);
+            }
+            else
+                AssertFailed();
+        }
+        else
+            AssertFailed();
+        if (g_pfnCloseWindowStation)
+            g_pfnCloseWindowStation(hWinStation0);
+    }
+    else
+        AssertFailed();
+}
+
+
+/**
+ * Extracts the user name + domain from a given UPN (User Principal Name, "joedoe@example.com") or
+ * Down-Level Logon Name format ("example.com\\joedoe") string.
+ *
+ * @return  IPRT status code.
+ * @param   pwszString      Pointer to string to extract the account info from.
+ * @param   pAccountInfo    Where to store the parsed account info.
+ *                          Must be free'd with rtProcWinFreeAccountInfo().
+ */
+static int rtProcWinParseAccountInfo(PRTUTF16 pwszString, PRTPROCWINACCOUNTINFO pAccountInfo)
+{
+    AssertPtrReturn(pwszString,   VERR_INVALID_POINTER);
+    AssertPtrReturn(pAccountInfo, VERR_INVALID_POINTER);
+
+    /*
+     * Note: UPN handling is defined in RFC 822. We only implement very rudimentary parsing for the user
+     *       name and domain fields though.
+     */
+    char *pszString;
+    int rc = RTUtf16ToUtf8(pwszString, &pszString);
+    if (RT_SUCCESS(rc))
+    {
+        do
+        {
+            /* UPN or FQDN handling needed? */
+            /** @todo Add more validation here as needed. Regular expressions would be nice. */
+            char *pszDelim = strchr(pszString, '@');
+            if (pszDelim) /* UPN name? */
+            {
+                rc = RTStrToUtf16Ex(pszString, pszDelim - pszString, &pAccountInfo->pwszUserName, 0, NULL);
+                if (RT_FAILURE(rc))
+                    break;
+
+                rc = RTStrToUtf16Ex(pszDelim + 1, RTSTR_MAX, &pAccountInfo->pwszDomain, 0, NULL);
+                if (RT_FAILURE(rc))
+                    break;
+            }
+            else if (pszDelim = strchr(pszString, '\\')) /* FQDN name? */
+            {
+                rc = RTStrToUtf16Ex(pszString, pszDelim - pszString, &pAccountInfo->pwszDomain, 0, NULL);
+                if (RT_FAILURE(rc))
+                    break;
+
+                rc = RTStrToUtf16Ex(pszDelim + 1, RTSTR_MAX, &pAccountInfo->pwszUserName, 0, NULL);
+                if (RT_FAILURE(rc))
+                    break;
+            }
+            else
+                rc = VERR_NOT_SUPPORTED;
+
+        } while (0);
+
+        RTStrFree(pszString);
+    }
+
+#ifdef DEBUG
+    LogRelFunc(("Name  : %ls\n", pAccountInfo->pwszUserName));
+    LogRelFunc(("Domain: %ls\n", pAccountInfo->pwszDomain));
+#endif
+
+    if (RT_FAILURE(rc))
+        LogRelFunc(("Parsing \"%ls\" failed with rc=%Rrc\n", pwszString, rc));
+    return rc;
+}
+
+
+static void rtProcWinFreeAccountInfo(PRTPROCWINACCOUNTINFO pAccountInfo)
+{
+    if (!pAccountInfo)
+        return;
+
+    if (pAccountInfo->pwszUserName)
+    {
+        RTUtf16Free(pAccountInfo->pwszUserName);
+        pAccountInfo->pwszUserName = NULL;
+    }
+
+    if (pAccountInfo->pwszDomain)
+    {
+        RTUtf16Free(pAccountInfo->pwszDomain);
+        pAccountInfo->pwszDomain = NULL;
+    }
+}
+
+
+/**
+ * Tries to resolve the name of the SID.
+ *
+ * @returns IPRT status code.
+ * @param   pSid        The SID to resolve.
+ * @param   ppwszName   Where to return the name. Use RTUtf16Free to free.
+ */
+static int rtProcWinSidToName(PSID pSid, PRTUTF16 *ppwszName)
+{
+    *ppwszName = NULL;
+
+    /*
+     * Use large initial buffers here to try avoid having to repeat the call.
+     */
+    DWORD cwcAllocated = 512;
+    while (cwcAllocated < _32K)
+    {
+        PRTUTF16 pwszName = RTUtf16Alloc(cwcAllocated * sizeof(RTUTF16));
+        AssertReturn(pwszName, VERR_NO_UTF16_MEMORY);
+        PRTUTF16 pwszDomain = RTUtf16Alloc(cwcAllocated * sizeof(RTUTF16));
+        AssertReturnStmt(pwszDomain, RTUtf16Free(pwszName), VERR_NO_UTF16_MEMORY);
+
+        DWORD cwcName   = cwcAllocated;
+        DWORD cwcDomain = cwcAllocated;
+        SID_NAME_USE SidNameUse = SidTypeUser;
+        if (LookupAccountSidW(NULL /*lpSystemName*/, pSid, pwszName, &cwcName, pwszDomain, &cwcDomain, &SidNameUse))
+        {
+            *ppwszName = pwszName;
+            RTUtf16Free(pwszDomain); /* may need this later. */
+            return VINF_SUCCESS;
+        }
+
+        DWORD const dwErr = GetLastError();
+        RTUtf16Free(pwszName);
+        RTUtf16Free(pwszDomain);
+        if (dwErr != ERROR_INSUFFICIENT_BUFFER)
+            return RTErrConvertFromWin32(dwErr);
+        cwcAllocated = RT_MAX(cwcName, cwcDomain) + 1;
+    }
+
+    return RTErrConvertFromWin32(ERROR_INSUFFICIENT_BUFFER);
+}
+
+
+/**
+ * Tries to resolve the user name for the token.
+ *
+ * @returns IPRT status code.
+ * @param   hToken      The token.
+ * @param   ppwszUser   Where to return the username. Use RTUtf16Free to free.
+ */
+static int rtProcWinTokenToUsername(HANDLE hToken, PRTUTF16 *ppwszUser)
+{
+    int rc = VINF_SUCCESS;
+    PSID pSid = rtProcWinGetTokenUserSid(hToken, &rc);
+    if (pSid)
+    {
+        rc = rtProcWinSidToName(pSid, ppwszUser);
+        RTMemFree(pSid);
+    }
+    else
+        *ppwszUser = NULL;
+    return rc;
+}
+
+
+/**
+ * Method \#2.
+ *
+ * @note pwszUser can be NULL when RTPROC_FLAGS_AS_IMPERSONATED_TOKEN is set.
+ */
+static int rtProcWinCreateAsUser2(PRTUTF16 pwszUser, PRTUTF16 pwszPassword, PRTUTF16 *ppwszExec, PRTUTF16 pwszCmdLine,
+                                  RTENV hEnv, DWORD dwCreationFlags,
+                                  STARTUPINFOW *pStartupInfo, PROCESS_INFORMATION *pProcInfo,
+                                  uint32_t fFlags, const char *pszExec, uint32_t idDesiredSession,
+                                  HANDLE hUserToken)
+{
+    /*
+     * So if we want to start a process from a service (RTPROC_FLAGS_SERVICE),
+     * we have to do the following:
+     * - Check the credentials supplied and get the user SID.
+     * - If valid get the correct Explorer/VBoxTray instance corresponding to that
+     *   user. This of course is only possible if that user is logged in (over
+     *   physical console or terminal services).
+     * - If we found the user's Explorer/VBoxTray app, use and modify the token to
+     *   use it in order to allow the newly started process to access the user's
+     *   desktop. If there's no Explorer/VBoxTray app we cannot display the started
+     *   process (but run it without UI).
+     *
+     * The following restrictions apply:
+     * - A process only can show its UI when the user the process should run
+     *   under is logged in (has a desktop).
+     * - We do not want to display a process of user A run on the desktop
+     *   of user B on multi session systems.
+     *
+     * The following rights are needed in order to use LogonUserW and
+     * CreateProcessAsUserW, so the local policy has to be modified to:
+     *  - SE_TCB_NAME                = Act as part of the operating system
+     *  - SE_ASSIGNPRIMARYTOKEN_NAME = Create/replace a (process) token object
+     *  - SE_INCREASE_QUOTA_NAME     = Increase quotas
+     *
+     * We may fail here with ERROR_PRIVILEGE_NOT_HELD.
+     */
+    DWORD   dwErr       = NO_ERROR;
+    HANDLE  hTokenLogon = INVALID_HANDLE_VALUE;
+    int rc = VINF_SUCCESS;
+    if (fFlags & RTPROC_FLAGS_TOKEN_SUPPLIED)
+        hTokenLogon = hUserToken;
+    else if (fFlags & RTPROC_FLAGS_AS_IMPERSONATED_TOKEN)
+        rc = rtProcWinGetThreadTokenHandle(GetCurrentThread(), &hTokenLogon);
+    else if (pwszUser == NULL)
+        rc = rtProcWinGetProcessTokenHandle(GetCurrentProcess(), &hTokenLogon);
+    else
+        rc = rtProcWinUserLogon(pwszUser, pwszPassword, &hTokenLogon);
+    if (RT_SUCCESS(rc))
+    {
+        BOOL   fRc;
+        bool   fFound = false;
+        HANDLE hTokenUserDesktop = INVALID_HANDLE_VALUE;
+
+        /*
+         * If the SERVICE flag is specified, we do something rather ugly to
+         * make things work at all.  We search for a known desktop process
+         * belonging to the user, grab its token and use it for launching
+         * the new process.  That way the process will have desktop access.
+         */
+        if (fFlags & RTPROC_FLAGS_SERVICE)
+        {
+            /*
+             * For the token search we need a SID.
+             */
+            PSID pSid = rtProcWinGetTokenUserSid(hTokenLogon, &rc);
+
+            /*
+             * If we got a valid SID, search the running processes.
+             */
+            /*
+             * If we got a valid SID, search the running processes.
+             */
+            if (pSid)
+            {
+                if (IsValidSid(pSid))
+                {
+                    /* Array of process names we want to look for. */
+                    static const char * const s_papszProcNames[] =
+                    {
+#ifdef VBOX             /* The explorer entry is a fallback in case GA aren't installed. */
+                        { "VBoxTray.exe" },
+# ifndef IN_GUEST
+                        { "VirtualBox.exe" },
+# endif
+#endif
+                        { "explorer.exe" },
+                        NULL
+                    };
+                    fFound = rtProcWinFindTokenByProcess(s_papszProcNames, pSid, idDesiredSession, &hTokenUserDesktop);
+                    dwErr  = 0;
+                }
+                else
+                {
+                    dwErr = GetLastError();
+                    LogRelFunc(("SID is invalid: %ld\n", dwErr));
+                    rc = dwErr != NO_ERROR ? RTErrConvertFromWin32(dwErr) : VERR_INTERNAL_ERROR_3;
+                }
+
+                RTMemFree(pSid);
+            }
+        }
+        /* else: !RTPROC_FLAGS_SERVICE: Nothing to do here right now. */
+
+#if 0
+        /*
+         * If we make LogonUserW to return an impersonation token, enable this
+         * to convert it into a primary token.
+         */
+        if (!fFound && detect-impersonation-token)
+        {
+            HANDLE hNewToken;
+            if (DuplicateTokenEx(hTokenLogon, MAXIMUM_ALLOWED, NULL /*SecurityAttribs*/,
+                                 SecurityIdentification, TokenPrimary, &hNewToken))
+            {
+                CloseHandle(hTokenLogon);
+                hTokenLogon = hNewToken;
+            }
+            else
+                AssertMsgFailed(("%d\n", GetLastError()));
+        }
+#endif
+
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * If we didn't find a matching VBoxTray, just use the token we got
+             * above from LogonUserW().  This enables us to at least run processes
+             * with desktop interaction without UI.
+             */
+            HANDLE hTokenToUse = fFound ? hTokenUserDesktop : hTokenLogon;
+            if (   !(fFlags & RTPROC_FLAGS_PROFILE)
+                || (g_pfnUnloadUserProfile && g_pfnLoadUserProfileW) )
+            {
+                /*
+                 * Load the profile, if requested.  (Must be done prior to creating the enviornment.)
+                 *
+                 * Note! We don't have sufficient rights when impersonating a user, but we can
+                 *       ASSUME the user is logged on and has its profile loaded into HKEY_USERS already.
+                 */
+                PROFILEINFOW ProfileInfo;
+                PRTUTF16     pwszUserFree = NULL;
+                RT_ZERO(ProfileInfo);
+                /** @todo r=bird: We probably don't need to load anything if pwszUser is NULL... */
+                if ((fFlags & (RTPROC_FLAGS_PROFILE | RTPROC_FLAGS_AS_IMPERSONATED_TOKEN)) == RTPROC_FLAGS_PROFILE)
+                {
+                    if (!pwszUser)
+                    {
+                        Assert(fFlags & RTPROC_FLAGS_AS_IMPERSONATED_TOKEN);
+                        rc = rtProcWinTokenToUsername(hTokenToUse, &pwszUserFree);
+                        pwszUser = pwszUserFree;
+                    }
+                    if (RT_SUCCESS(rc))
+                    {
+                        ProfileInfo.dwSize     = sizeof(ProfileInfo);
+                        ProfileInfo.dwFlags    = PI_NOUI; /* Prevents the display of profile error messages. */
+                        ProfileInfo.lpUserName = pwszUser;
+                        if (!g_pfnLoadUserProfileW(hTokenToUse, &ProfileInfo))
+                            rc = RTErrConvertFromWin32(GetLastError());
+                    }
+                }
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * Create the environment.
+                     */
+                    RTENV hEnvFinal;
+                    rc = rtProcWinCreateEnvFromToken(hTokenToUse, hEnv, fFlags, &hEnvFinal);
+                    if (RT_SUCCESS(rc))
+                    {
+                        PRTUTF16 pwszzBlock;
+                        rc = RTEnvQueryUtf16Block(hEnvFinal, &pwszzBlock);
+                        if (RT_SUCCESS(rc))
+                        {
+                            rc = rtProcWinFindExe(fFlags, hEnv, pszExec, ppwszExec);
+                            if (RT_SUCCESS(rc))
+                            {
+                                HWINSTA hOldWinStation = NULL;
+                                if (   !fFound
+                                    && g_enmWinVer <= kRTWinOSType_NT4) /** @todo test newer versions... */
+                                    rtProcWinStationPrep(hTokenToUse, pStartupInfo, &hOldWinStation);
+
+                                /*
+                                 * Useful KB articles:
+                                 *      http://support.microsoft.com/kb/165194/
+                                 *      http://support.microsoft.com/kb/184802/
+                                 *      http://support.microsoft.com/kb/327618/
+                                 */
+                                if (g_pfnCreateProcessAsUserW)
+                                {
+                                    fRc = g_pfnCreateProcessAsUserW(hTokenToUse,
+                                                                    *ppwszExec,
+                                                                    pwszCmdLine,
+                                                                    NULL,         /* pProcessAttributes */
+                                                                    NULL,         /* pThreadAttributes */
+                                                                    TRUE,         /* fInheritHandles */
+                                                                    dwCreationFlags,
+                                                                    /** @todo Warn about exceeding 8192 bytes
+                                                                     *        on XP and up. */
+                                                                    pwszzBlock,   /* lpEnvironment */
+                                                                    NULL,         /* pCurrentDirectory */
+                                                                    pStartupInfo,
+                                                                    pProcInfo);
+                                    if (fRc)
+                                        rc = VINF_SUCCESS;
+                                    else
+                                    {
+                                        dwErr = GetLastError();
+                                        if (dwErr == ERROR_PRIVILEGE_NOT_HELD)
+                                            rc = rtProcWinFigureWhichPrivilegeNotHeld2();
+                                        else
+                                            rc = RTErrConvertFromWin32(dwErr);
+                                    }
+                                }
+                                else
+                                    rc = VERR_NOT_SUPPORTED;
+
+                                if (hOldWinStation)
+                                    SetProcessWindowStation(hOldWinStation);
+                            }
+                            RTEnvFreeUtf16Block(pwszzBlock);
+                        }
+
+                        if (hEnvFinal != hEnv)
+                            RTEnvDestroy(hEnvFinal);
+                    }
+
+                    if ((fFlags & RTPROC_FLAGS_PROFILE) && ProfileInfo.hProfile)
+                    {
+                        fRc = g_pfnUnloadUserProfile(hTokenToUse, ProfileInfo.hProfile);
+#ifdef RT_STRICT
+                        if (!fRc)
+                        {
+                            DWORD dwErr2 = GetLastError();
+                            AssertMsgFailed(("Unloading user profile failed with error %u (%#x) - Are all handles closed? (dwErr=%u)",
+                                             dwErr2, dwErr2, dwErr));
+                        }
+#endif
+                    }
+                    if (pwszUserFree)
+                        RTUtf16Free(pwszUserFree);
+                }
+            }
+            else
+                rc = VERR_SYMBOL_NOT_FOUND;
+        } /* Account lookup succeeded? */
+
+        if (hTokenUserDesktop != INVALID_HANDLE_VALUE)
+            CloseHandle(hTokenUserDesktop);
+        if (   !(fFlags & RTPROC_FLAGS_TOKEN_SUPPLIED)
+            && hTokenLogon != INVALID_HANDLE_VALUE)
+            CloseHandle(hTokenLogon);
+
+        if (rc == VERR_UNRESOLVED_ERROR)
+            LogRelFunc(("dwErr=%u (%#x), rc=%Rrc\n", dwErr, dwErr, rc));
+    }
+
+    return rc;
+}
+
+
+/**
+ * Plants a standard handle into a child process on older windows versions.
+ *
+ * This is only needed when using CreateProcessWithLogonW on older windows
+ * versions.  It would appear that newer versions of windows does this for us.
+ *
+ * @param   hSrcHandle              The source handle.
+ * @param   hDstProcess             The child process handle.
+ * @param   offProcParamMember      The offset to RTL_USER_PROCESS_PARAMETERS.
+ * @param   ppvDstProcParamCache    Where where cached the address of
+ *                                  RTL_USER_PROCESS_PARAMETERS in the child.
+ */
+static void rtProcWinDupStdHandleIntoChild(HANDLE hSrcHandle, HANDLE hDstProcess, uint32_t offProcParamMember,
+                                           PVOID *ppvDstProcParamCache)
+{
+    if (hSrcHandle != NULL && hSrcHandle != INVALID_HANDLE_VALUE)
+    {
+        HANDLE hDstHandle;
+        if (DuplicateHandle(GetCurrentProcess(), hSrcHandle, hDstProcess, &hDstHandle,
+                            0 /*IgnoredDesiredAccess*/, FALSE /*fInherit*/, DUPLICATE_SAME_ACCESS))
+        {
+            if (hSrcHandle == hDstHandle)
+                return;
+
+            if (!*ppvDstProcParamCache)
+            {
+                PROCESS_BASIC_INFORMATION BasicInfo;
+                ULONG cbIgn;
+                NTSTATUS rcNt = NtQueryInformationProcess(hDstProcess, ProcessBasicInformation,
+                                                          &BasicInfo, sizeof(BasicInfo), &cbIgn);
+                if (NT_SUCCESS(rcNt))
+                {
+                    SIZE_T cbCopied = 0;
+                    if (!ReadProcessMemory(hDstProcess,
+                                           (char *)BasicInfo.PebBaseAddress + RT_UOFFSETOF(PEB_COMMON, ProcessParameters),
+                                           ppvDstProcParamCache, sizeof(*ppvDstProcParamCache), &cbCopied))
+                    {
+                        AssertMsgFailed(("PebBaseAddress=%p %d\n", BasicInfo.PebBaseAddress, GetLastError()));
+                        *ppvDstProcParamCache = NULL;
+                    }
+                }
+                else
+                    AssertMsgFailed(("rcNt=%#x\n", rcNt));
+            }
+            if (*ppvDstProcParamCache)
+            {
+                if (WriteProcessMemory(hDstProcess, (char *)*ppvDstProcParamCache + offProcParamMember,
+                                       &hDstHandle, sizeof(hDstHandle), NULL))
+                    return;
+            }
+
+            /*
+             * Close the handle.
+             */
+            HANDLE hSrcHandle2;
+            if (DuplicateHandle(hDstProcess, hDstHandle, GetCurrentProcess(), &hSrcHandle2,
+                                0 /*IgnoredDesiredAccess*/, FALSE /*fInherit*/, DUPLICATE_SAME_ACCESS | DUPLICATE_CLOSE_SOURCE))
+                CloseHandle(hSrcHandle2);
+            else
+                AssertMsgFailed(("hDstHandle=%p %u\n", hDstHandle, GetLastError()));
+        }
+        else
+            AssertMsg(GetLastError() == ERROR_INVALID_PARAMETER, ("%u\n", GetLastError()));
+    }
+}
+
+
+/**
+ * Method \#1.
+ *
+ * This method requires Windows 2000 or later.  It may fail if the process is
+ * running under the SYSTEM account (like a service, ERROR_ACCESS_DENIED) on
+ * newer platforms (however, this works on W2K!).
+ */
+static int rtProcWinCreateAsUser1(PRTUTF16 pwszUser, PRTUTF16 pwszPassword, PRTUTF16 *ppwszExec, PRTUTF16 pwszCmdLine,
+                                  RTENV hEnv, DWORD dwCreationFlags,
+                                  STARTUPINFOW *pStartupInfo, PROCESS_INFORMATION *pProcInfo,
+                                  uint32_t fFlags, const char *pszExec)
+{
+    /* The CreateProcessWithLogonW API was introduced with W2K and later.  It uses a service
+       for launching the process. */
+    if (!g_pfnCreateProcessWithLogonW)
+        return VERR_SYMBOL_NOT_FOUND;
+
+    /*
+     * Create the environment block and find the executable first.
+     *
+     * We try to skip this when RTPROC_FLAGS_PROFILE is set so we can sidestep
+     * potential missing TCB privilege issues when calling UserLogonW.  At least
+     * NT4 and W2K requires the trusted code base (TCB) privilege for logon use.
+     * Passing pwszzBlock=NULL and LOGON_WITH_PROFILE means the child process
+     * gets the environment specified by the user profile.
+     */
+    int      rc;
+    PRTUTF16 pwszzBlock = NULL;
+
+    /* Eliminating the path search flags simplifies things a little. */
+    if (   (fFlags & RTPROC_FLAGS_SEARCH_PATH)
+        && (RTPathHasPath(pszExec) || RTPathExists(pszExec)))
+        fFlags &= ~RTPROC_FLAGS_SEARCH_PATH;
+
+    /*
+     * No profile is simple, as is a user specified environment (no change record).
+     */
+    if (   !(fFlags & RTPROC_FLAGS_PROFILE)
+        || (   !(fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)
+            && hEnv != RTENV_DEFAULT))
+        rc = rtProcWinCreateEnvBlockAndFindExe(fFlags, hEnv, pszExec, &pwszzBlock, ppwszExec);
+    /*
+     * Default profile environment without changes or path searching we leave
+     * to the service that implements the API.
+     */
+    else if (   hEnv == RTENV_DEFAULT
+             && !(fFlags & (RTPROC_FLAGS_ENV_CHANGE_RECORD | RTPROC_FLAGS_SEARCH_PATH)))
+    {
+        pwszzBlock = NULL;
+        rc = VINF_SUCCESS;
+    }
+    /*
+     * Otherwise, we need to get the user profile environment.
+     */
+    else
+    {
+        RTENV  hEnvToUse   = NIL_RTENV;
+        HANDLE hTokenLogon = INVALID_HANDLE_VALUE;
+        rc = rtProcWinUserLogon(pwszUser, pwszPassword, &hTokenLogon);
+        if (RT_SUCCESS(rc))
+        {
+            /* CreateEnvFromToken docs says we should load the profile, though
+               we haven't observed any difference when not doing it.  Maybe it's
+               only an issue with roaming profiles or something similar... */
+            PROFILEINFOW ProfileInfo;
+            RT_ZERO(ProfileInfo);
+            ProfileInfo.dwSize     = sizeof(ProfileInfo);
+            ProfileInfo.lpUserName = pwszUser;
+            ProfileInfo.dwFlags    = PI_NOUI; /* Prevents the display of profile error messages. */
+
+            if (g_pfnLoadUserProfileW(hTokenLogon, &ProfileInfo))
+            {
+                /*
+                 * Do what we need to do.  Don't keep any temp environment object.
+                 */
+                rc = rtProcWinCreateEnvFromToken(hTokenLogon, hEnv, fFlags, &hEnvToUse);
+                if (RT_SUCCESS(rc))
+                {
+                    rc = rtProcWinFindExe(fFlags, hEnv, pszExec, ppwszExec);
+                    if (RT_SUCCESS(rc))
+                        rc = RTEnvQueryUtf16Block(hEnvToUse, &pwszzBlock);
+                    if (hEnvToUse != hEnv)
+                        RTEnvDestroy(hEnvToUse);
+                }
+
+                if (!g_pfnUnloadUserProfile(hTokenLogon, ProfileInfo.hProfile))
+                    AssertFailed();
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            if (hTokenLogon != INVALID_HANDLE_VALUE)
+                CloseHandle(hTokenLogon);
+        }
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Create the process.
+         */
+        Assert(!(dwCreationFlags & CREATE_SUSPENDED));
+        bool const fCreatedSuspended = g_enmWinVer < kRTWinOSType_XP;
+        BOOL fRc = g_pfnCreateProcessWithLogonW(pwszUser,
+                                                NULL,                       /* lpDomain*/
+                                                pwszPassword,
+                                                fFlags & RTPROC_FLAGS_PROFILE ? 1 /*LOGON_WITH_PROFILE*/ : 0,
+                                                *ppwszExec,
+                                                pwszCmdLine,
+                                                dwCreationFlags | (fCreatedSuspended ? CREATE_SUSPENDED : 0),
+                                                pwszzBlock,
+                                                NULL,                       /* pCurrentDirectory */
+                                                pStartupInfo,
+                                                pProcInfo);
+        if (fRc)
+        {
+            if (!fCreatedSuspended)
+                rc = VINF_SUCCESS;
+            else
+            {
+                /*
+                 * Duplicate standard handles into the child process, we ignore failures here as it's
+                 * legal to have bad standard handle values and we cannot dup console I/O handles.*
+                 */
+                PVOID pvDstProcParamCache = NULL;
+                rtProcWinDupStdHandleIntoChild(pStartupInfo->hStdInput, pProcInfo->hProcess,
+                                               RT_UOFFSETOF(RTL_USER_PROCESS_PARAMETERS, StandardInput), &pvDstProcParamCache);
+                rtProcWinDupStdHandleIntoChild(pStartupInfo->hStdOutput, pProcInfo->hProcess,
+                                               RT_UOFFSETOF(RTL_USER_PROCESS_PARAMETERS, StandardOutput), &pvDstProcParamCache);
+                rtProcWinDupStdHandleIntoChild(pStartupInfo->hStdError,  pProcInfo->hProcess,
+                                               RT_UOFFSETOF(RTL_USER_PROCESS_PARAMETERS, StandardError), &pvDstProcParamCache);
+
+                if (ResumeThread(pProcInfo->hThread) != ~(DWORD)0)
+                    rc = VINF_SUCCESS;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+                if (RT_FAILURE(rc))
+                {
+                    TerminateProcess(pProcInfo->hProcess, 127);
+                    CloseHandle(pProcInfo->hThread);
+                    CloseHandle(pProcInfo->hProcess);
+                }
+            }
+        }
+        else
+        {
+            DWORD dwErr = GetLastError();
+            rc = RTErrConvertFromWin32(dwErr);
+            if (rc == VERR_UNRESOLVED_ERROR)
+                LogRelFunc(("CreateProcessWithLogonW failed: dwErr=%u (%#x), rc=%Rrc\n", dwErr, dwErr, rc));
+        }
+        if (pwszzBlock)
+            RTEnvFreeUtf16Block(pwszzBlock);
+    }
+    return rc;
+}
+
+
+static int rtProcWinCreateAsUser(PRTUTF16 pwszUser, PRTUTF16 pwszPassword, PRTUTF16 *ppwszExec, PRTUTF16 pwszCmdLine,
+                                 RTENV hEnv, DWORD dwCreationFlags,
+                                 STARTUPINFOW *pStartupInfo, PROCESS_INFORMATION *pProcInfo,
+                                 uint32_t fFlags, const char *pszExec, uint32_t idDesiredSession,
+                                 HANDLE hUserToken)
+{
+    /*
+     * If we run as a service CreateProcessWithLogon will fail, so don't even
+     * try it (because of Local System context).  If we got an impersonated token
+     * we should use, we also have to have to skip over this approach.
+     * Note! This method is very slow on W2K.
+     */
+    if (!(fFlags & (RTPROC_FLAGS_SERVICE | RTPROC_FLAGS_AS_IMPERSONATED_TOKEN | RTPROC_FLAGS_TOKEN_SUPPLIED)))
+    {
+        AssertPtr(pwszUser);
+        int rc = rtProcWinCreateAsUser1(pwszUser, pwszPassword, ppwszExec, pwszCmdLine,
+                                        hEnv, dwCreationFlags, pStartupInfo, pProcInfo, fFlags, pszExec);
+        if (RT_SUCCESS(rc))
+            return rc;
+    }
+    return rtProcWinCreateAsUser2(pwszUser, pwszPassword, ppwszExec, pwszCmdLine, hEnv, dwCreationFlags,
+                                  pStartupInfo, pProcInfo, fFlags, pszExec, idDesiredSession, hUserToken);
+}
+
+
+/**
+ * RTPathTraverseList callback used by rtProcWinFindExe to locate the
+ * executable.
+ */
+static DECLCALLBACK(int) rtPathFindExec(char const *pchPath, size_t cchPath, void *pvUser1, void *pvUser2)
+{
+    const char *pszExec     = (const char *)pvUser1;
+    char       *pszRealExec = (char *)pvUser2;
+    int rc = RTPathJoinEx(pszRealExec, RTPATH_MAX, pchPath, cchPath, pszExec, RTSTR_MAX, RTPATH_STR_F_STYLE_HOST);
+    if (RT_FAILURE(rc))
+        return rc;
+    if (RTFileExists(pszRealExec))
+        return VINF_SUCCESS;
+    return VERR_TRY_AGAIN;
+}
+
+
+/**
+ * Locate the executable file if necessary.
+ *
+ * @returns IPRT status code.
+ * @param   pszExec         The UTF-8 executable string passed in by the user.
+ * @param   fFlags          The process creation flags pass in by the user.
+ * @param   hEnv            The environment to get the path variabel from.
+ * @param   ppwszExec       Pointer to the variable pointing to the UTF-16
+ *                          converted string.  If we find something, the current
+ *                          pointer will be free (RTUtf16Free) and
+ *                          replaced by a new one.
+ */
+static int rtProcWinFindExe(uint32_t fFlags, RTENV hEnv, const char *pszExec, PRTUTF16 *ppwszExec)
+{
+    /*
+     * Return immediately if we're not asked to search, or if the file has a
+     * path already or if it actually exists in the current directory.
+     */
+    if (   !(fFlags & RTPROC_FLAGS_SEARCH_PATH)
+        || RTPathHavePath(pszExec)
+        || RTPathExists(pszExec) )
+        return VINF_SUCCESS;
+
+    /*
+     * Search the Path or PATH variable for the file.
+     */
+    char *pszPath;
+    if (RTEnvExistEx(hEnv, "PATH"))
+        pszPath = RTEnvDupEx(hEnv, "PATH");
+    else if (RTEnvExistEx(hEnv, "Path"))
+        pszPath = RTEnvDupEx(hEnv, "Path");
+    else
+        return VERR_FILE_NOT_FOUND;
+
+    char szRealExec[RTPATH_MAX];
+    int rc = RTPathTraverseList(pszPath, ';', rtPathFindExec, (void *)pszExec, &szRealExec[0]);
+    RTStrFree(pszPath);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Replace the executable string.
+         */
+        RTPathWinFree(*ppwszExec);
+        *ppwszExec = NULL;
+        rc = RTPathWinFromUtf8(ppwszExec, szRealExec, 0 /*fFlags*/);
+    }
+    else if (rc == VERR_END_OF_STRING)
+        rc = VERR_FILE_NOT_FOUND;
+    return rc;
+}
+
+
+/**
+ * Creates the UTF-16 environment block and, if necessary, find the executable.
+ *
+ * @returns IPRT status code.
+ * @param   fFlags          The process creation flags pass in by the user.
+ * @param   hEnv            The environment handle passed by the user.
+ * @param   pszExec         See rtProcWinFindExe.
+ * @param   ppwszzBlock     Where RTEnvQueryUtf16Block returns the block.
+ * @param   ppwszExec       See rtProcWinFindExe.
+ */
+static int rtProcWinCreateEnvBlockAndFindExe(uint32_t fFlags, RTENV hEnv, const char *pszExec,
+                                             PRTUTF16 *ppwszzBlock, PRTUTF16 *ppwszExec)
+{
+    int rc;
+
+    /*
+     * In most cases, we just need to convert the incoming enviornment to a
+     * UTF-16 environment block.
+     */
+    RTENV hEnvToUse = NIL_RTENV; /* (MSC maybe used uninitialized) */
+    if (   !(fFlags & (RTPROC_FLAGS_PROFILE | RTPROC_FLAGS_ENV_CHANGE_RECORD))
+        || (hEnv == RTENV_DEFAULT && !(fFlags & RTPROC_FLAGS_PROFILE))
+        || (hEnv != RTENV_DEFAULT && !(fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD)) )
+    {
+        hEnvToUse = hEnv;
+        rc = VINF_SUCCESS;
+    }
+    else if (fFlags & RTPROC_FLAGS_PROFILE)
+    {
+        /*
+         * We need to get the profile environment for the current user.
+         */
+        Assert((fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD) || hEnv == RTENV_DEFAULT);
+        AssertReturn(g_pfnCreateEnvironmentBlock && g_pfnDestroyEnvironmentBlock, VERR_SYMBOL_NOT_FOUND);
+        AssertReturn(g_pfnLoadUserProfileW && g_pfnUnloadUserProfile, VERR_SYMBOL_NOT_FOUND);
+        HANDLE hToken;
+        if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY | TOKEN_DUPLICATE | TOKEN_IMPERSONATE, &hToken))
+        {
+            rc = rtProcWinCreateEnvFromToken(hToken, hEnv, fFlags, &hEnvToUse);
+            CloseHandle(hToken);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        /*
+         * Apply hEnv as a change record on top of the default environment.
+         */
+        Assert(fFlags & RTPROC_FLAGS_ENV_CHANGE_RECORD);
+        rc = RTEnvClone(&hEnvToUse, RTENV_DEFAULT);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTEnvApplyChanges(hEnvToUse, hEnv);
+            if (RT_FAILURE(rc))
+                RTEnvDestroy(hEnvToUse);
+        }
+    }
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Query the UTF-16 environment block and locate the executable (if needed).
+         */
+        rc = RTEnvQueryUtf16Block(hEnvToUse, ppwszzBlock);
+        if (RT_SUCCESS(rc))
+            rc = rtProcWinFindExe(fFlags, hEnvToUse, pszExec, ppwszExec);
+
+        if (hEnvToUse != hEnv)
+            RTEnvDestroy(hEnvToUse);
+    }
+
+    return rc;
+}
+
+
+RTR3DECL(int)   RTProcCreateEx(const char *pszExec, const char * const *papszArgs, RTENV hEnv, uint32_t fFlags,
+                               PCRTHANDLE phStdIn, PCRTHANDLE phStdOut, PCRTHANDLE phStdErr, const char *pszAsUser,
+                               const char *pszPassword, void *pvExtraData, PRTPROCESS phProcess)
+{
+    /*
+     * Input validation
+     */
+    AssertPtrReturn(pszExec, VERR_INVALID_POINTER);
+    AssertReturn(*pszExec, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTPROC_FLAGS_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & RTPROC_FLAGS_DETACHED) || !phProcess, VERR_INVALID_PARAMETER);
+    AssertReturn(hEnv != NIL_RTENV, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(papszArgs, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pszAsUser, VERR_INVALID_POINTER);
+    AssertReturn(!pszAsUser || *pszAsUser, VERR_INVALID_PARAMETER);
+    AssertReturn(!pszPassword || pszAsUser, VERR_INVALID_PARAMETER);
+    AssertPtrNullReturn(pszPassword, VERR_INVALID_POINTER);
+
+    /* Extra data: */
+    uint32_t idDesiredSession = UINT32_MAX;
+    if (   (fFlags & (RTPROC_FLAGS_DESIRED_SESSION_ID | RTPROC_FLAGS_SERVICE))
+        ==           (RTPROC_FLAGS_DESIRED_SESSION_ID | RTPROC_FLAGS_SERVICE))
+    {
+        AssertPtrReturn(pvExtraData, VERR_INVALID_POINTER);
+        idDesiredSession = *(uint32_t *)pvExtraData;
+    }
+    else
+        AssertReturn(!(fFlags & RTPROC_FLAGS_DESIRED_SESSION_ID), VERR_INVALID_FLAGS);
+
+    HANDLE hUserToken = NULL;
+    if (fFlags & RTPROC_FLAGS_TOKEN_SUPPLIED)
+        hUserToken = *(HANDLE *)pvExtraData;
+
+    /*
+     * Initialize the globals.
+     */
+    int rc = RTOnce(&g_rtProcWinInitOnce, rtProcWinInitOnce, NULL);
+    AssertRCReturn(rc, rc);
+    if (   pszAsUser
+        || (fFlags & (RTPROC_FLAGS_PROFILE | RTPROC_FLAGS_SERVICE | RTPROC_FLAGS_AS_IMPERSONATED_TOKEN
+                      | RTPROC_FLAGS_TOKEN_SUPPLIED)))
+    {
+        rc = RTOnce(&g_rtProcWinResolveOnce, rtProcWinResolveOnce, NULL);
+        AssertRCReturn(rc, rc);
+    }
+
+    /*
+     * Get the file descriptors for the handles we've been passed.
+     *
+     * It seems there is no point in trying to convince a child process's CRT
+     * that any of the standard file handles is non-TEXT.  So, we don't...
+     */
+    STARTUPINFOW StartupInfo;
+    RT_ZERO(StartupInfo);
+    StartupInfo.cb = sizeof(StartupInfo);
+    StartupInfo.dwFlags   = STARTF_USESTDHANDLES;
+#if 1 /* The CRT should keep the standard handles up to date. */
+    StartupInfo.hStdInput  = GetStdHandle(STD_INPUT_HANDLE);
+    StartupInfo.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
+    StartupInfo.hStdError  = GetStdHandle(STD_ERROR_HANDLE);
+#else
+    StartupInfo.hStdInput  = _get_osfhandle(0);
+    StartupInfo.hStdOutput = _get_osfhandle(1);
+    StartupInfo.hStdError  = _get_osfhandle(2);
+#endif
+    /* If we want to have a hidden process (e.g. not visible to
+     * to the user) use the STARTUPINFO flags. */
+    if (fFlags & RTPROC_FLAGS_HIDDEN)
+    {
+        StartupInfo.dwFlags |= STARTF_USESHOWWINDOW;
+        StartupInfo.wShowWindow = SW_HIDE;
+    }
+
+    PCRTHANDLE  paHandles[3] = { phStdIn,                   phStdOut,                   phStdErr };
+    HANDLE     *aphStds[3]   = { &StartupInfo.hStdInput,    &StartupInfo.hStdOutput,    &StartupInfo.hStdError };
+    DWORD       afInhStds[3] = { 0xffffffff,                0xffffffff,                 0xffffffff };
+    HANDLE      ahStdDups[3] = { INVALID_HANDLE_VALUE,      INVALID_HANDLE_VALUE,       INVALID_HANDLE_VALUE };
+    for (int i = 0; i < 3; i++)
+    {
+        if (paHandles[i])
+        {
+            AssertPtrReturn(paHandles[i], VERR_INVALID_POINTER);
+            switch (paHandles[i]->enmType)
+            {
+                case RTHANDLETYPE_FILE:
+                {
+                    HANDLE hNativeFile = paHandles[i]->u.hFile != NIL_RTFILE
+                                       ? (HANDLE)RTFileToNative(paHandles[i]->u.hFile)
+                                       : INVALID_HANDLE_VALUE;
+                    if (   hNativeFile == *aphStds[i]
+                        && g_enmWinVer == kRTWinOSType_NT310)
+                        continue;
+                    *aphStds[i] = hNativeFile;
+                    break;
+                }
+
+                case RTHANDLETYPE_PIPE:
+                    *aphStds[i] = paHandles[i]->u.hPipe != NIL_RTPIPE
+                                ? (HANDLE)RTPipeToNative(paHandles[i]->u.hPipe)
+                                : INVALID_HANDLE_VALUE;
+                    if (   g_enmWinVer == kRTWinOSType_NT310
+                        && *aphStds[i] == INVALID_HANDLE_VALUE)
+                    {
+                        AssertMsgReturn(RTPipeGetCreationInheritability(paHandles[i]->u.hPipe), ("%Rrc %p\n", rc, *aphStds[i]),
+                                        VERR_INVALID_STATE);
+                        continue;
+                    }
+                    break;
+
+                case RTHANDLETYPE_SOCKET:
+                    *aphStds[i] = paHandles[i]->u.hSocket != NIL_RTSOCKET
+                                ? (HANDLE)RTSocketToNative(paHandles[i]->u.hSocket)
+                                : INVALID_HANDLE_VALUE;
+                    break;
+
+                default:
+                    AssertMsgFailedReturn(("%d: %d\n", i, paHandles[i]->enmType), VERR_INVALID_PARAMETER);
+            }
+
+            /* Get the inheritability of the handle. */
+            if (*aphStds[i] != INVALID_HANDLE_VALUE)
+            {
+                if (!g_pfnGetHandleInformation)
+                    afInhStds[i] = 0; /* No handle info on NT 3.1, so ASSUME it is not inheritable. */
+                else if (!g_pfnGetHandleInformation(*aphStds[i], &afInhStds[i]))
+                {
+                    rc = RTErrConvertFromWin32(GetLastError());
+                    AssertMsgFailedReturn(("%Rrc aphStds[%d] => %p paHandles[%d]={%d,%p}\n",
+                                           rc, i, *aphStds[i], i, paHandles[i]->enmType, paHandles[i]->u.uInt),
+                                          rc);
+                }
+            }
+        }
+    }
+
+    /*
+     * Set the inheritability any handles we're handing the child.
+     *
+     * Note! On NT 3.1 there is no SetHandleInformation, so we have to duplicate
+     *       the handles to make sure they are inherited by the child.
+     */
+    rc = VINF_SUCCESS;
+    for (int i = 0; i < 3; i++)
+        if (   (afInhStds[i] != 0xffffffff)
+            && !(afInhStds[i] & HANDLE_FLAG_INHERIT))
+        {
+            if (!g_pfnSetHandleInformation)
+            {
+                if (DuplicateHandle(GetCurrentProcess(), *aphStds[i], GetCurrentProcess(), &ahStdDups[i],
+                                    i == 0 ? GENERIC_READ : GENERIC_WRITE, TRUE /*fInheritHandle*/, DUPLICATE_SAME_ACCESS))
+                    *aphStds[i] = ahStdDups[i];
+                else
+                {
+                    rc = RTErrConvertFromWin32(GetLastError());
+                    AssertMsgFailedBreak(("%Rrc aphStds[%u] => %p\n", rc, i, *aphStds[i]));
+                }
+            }
+            else if (!g_pfnSetHandleInformation(*aphStds[i], HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT))
+            {
+                rc = RTErrConvertFromWin32(GetLastError());
+                if (rc == VERR_INVALID_FUNCTION && g_enmWinVer == kRTWinOSType_NT310)
+                    rc = VINF_SUCCESS;
+                else
+                    AssertMsgFailedBreak(("%Rrc aphStds[%u] => %p\n", rc, i, *aphStds[i]));
+            }
+        }
+
+    /*
+     * Create the command line and convert the executable name.
+     */
+    PRTUTF16 pwszCmdLine = NULL; /* Shut up, MSC! */
+    if (RT_SUCCESS(rc))
+        rc = RTGetOptArgvToUtf16String(&pwszCmdLine, papszArgs,
+                                       !(fFlags & RTPROC_FLAGS_UNQUOTED_ARGS)
+                                       ? RTGETOPTARGV_CNV_QUOTE_MS_CRT : RTGETOPTARGV_CNV_UNQUOTED);
+    if (RT_SUCCESS(rc))
+    {
+        PRTUTF16 pwszExec;
+        rc = RTPathWinFromUtf8(&pwszExec, pszExec, 0 /*fFlags*/);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Get going...
+             */
+            PROCESS_INFORMATION ProcInfo;
+            RT_ZERO(ProcInfo);
+            DWORD dwCreationFlags = CREATE_UNICODE_ENVIRONMENT;
+            if (fFlags & RTPROC_FLAGS_DETACHED)
+                dwCreationFlags |= DETACHED_PROCESS;
+            if (fFlags & RTPROC_FLAGS_NO_WINDOW)
+                dwCreationFlags |= CREATE_NO_WINDOW;
+
+            /*
+             * Only use the normal CreateProcess stuff if we have no user name
+             * and we are not running from a (Windows) service. Otherwise use
+             * the more advanced version in rtProcWinCreateAsUser().
+             */
+            if (   pszAsUser == NULL
+                && !(fFlags & (RTPROC_FLAGS_SERVICE | RTPROC_FLAGS_AS_IMPERSONATED_TOKEN | RTPROC_FLAGS_TOKEN_SUPPLIED)))
+            {
+                /* Create the environment block first. */
+                PRTUTF16 pwszzBlock;
+                rc = rtProcWinCreateEnvBlockAndFindExe(fFlags, hEnv, pszExec, &pwszzBlock, &pwszExec);
+                if (RT_SUCCESS(rc))
+                {
+                    if (CreateProcessW(pwszExec,
+                                       pwszCmdLine,
+                                       NULL,         /* pProcessAttributes */
+                                       NULL,         /* pThreadAttributes */
+                                       TRUE,         /* fInheritHandles */
+                                       dwCreationFlags,
+                                       pwszzBlock,
+                                       NULL,         /* pCurrentDirectory */
+                                       &StartupInfo,
+                                       &ProcInfo))
+                        rc = VINF_SUCCESS;
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                    RTEnvFreeUtf16Block(pwszzBlock);
+                }
+            }
+            else
+            {
+                /*
+                 * Convert the additional parameters and use a helper
+                 * function to do the actual work.
+                 */
+                PRTUTF16 pwszUser = NULL;
+                if (pszAsUser)
+                    rc = RTStrToUtf16(pszAsUser, &pwszUser);
+                if (RT_SUCCESS(rc))
+                {
+                    PRTUTF16 pwszPassword;
+                    rc = RTStrToUtf16(pszPassword ? pszPassword : "", &pwszPassword);
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = rtProcWinCreateAsUser(pwszUser, pwszPassword, &pwszExec, pwszCmdLine, hEnv, dwCreationFlags,
+                                                   &StartupInfo, &ProcInfo, fFlags, pszExec, idDesiredSession,
+                                                   hUserToken);
+
+                        if (pwszPassword && *pwszPassword)
+                            RTMemWipeThoroughly(pwszPassword, RTUtf16Len(pwszPassword), 5);
+                        RTUtf16Free(pwszPassword);
+                    }
+                    RTUtf16Free(pwszUser);
+                }
+            }
+            if (RT_SUCCESS(rc))
+            {
+                CloseHandle(ProcInfo.hThread);
+                if (phProcess)
+                {
+                    /*
+                     * Add the process to the child process list so RTProcWait can reuse and close
+                     * the process handle, unless, of course, the caller has no intention waiting.
+                     */
+                    if (!(fFlags & RTPROC_FLAGS_NO_WAIT))
+                        rtProcWinAddPid(ProcInfo.dwProcessId, ProcInfo.hProcess);
+                    else
+                        CloseHandle(ProcInfo.hProcess);
+                    *phProcess = ProcInfo.dwProcessId;
+                }
+                else
+                    CloseHandle(ProcInfo.hProcess);
+                rc = VINF_SUCCESS;
+            }
+            RTPathWinFree(pwszExec);
+        }
+        RTUtf16Free(pwszCmdLine);
+    }
+
+    if (g_pfnSetHandleInformation)
+    {
+        /* Undo any handle inherit changes. */
+        for (int i = 0; i < 3; i++)
+            if (   (afInhStds[i] != 0xffffffff)
+                && !(afInhStds[i] & HANDLE_FLAG_INHERIT))
+            {
+                if (   !g_pfnSetHandleInformation(*aphStds[i], HANDLE_FLAG_INHERIT, 0)
+                    && (   GetLastError() != ERROR_INVALID_FUNCTION
+                        || g_enmWinVer != kRTWinOSType_NT310) )
+                    AssertMsgFailed(("%Rrc %p\n", RTErrConvertFromWin32(GetLastError()), *aphStds[i]));
+            }
+    }
+    else
+    {
+        /* Close handles duplicated for correct inheritance. */
+        for (int i = 0; i < 3; i++)
+            if (ahStdDups[i] != INVALID_HANDLE_VALUE)
+                CloseHandle(ahStdDups[i]);
+    }
+
+    return rc;
+}
+
+
+
+RTR3DECL(int) RTProcWait(RTPROCESS Process, unsigned fFlags, PRTPROCSTATUS pProcStatus)
+{
+    AssertReturn(!(fFlags & ~(RTPROCWAIT_FLAGS_BLOCK | RTPROCWAIT_FLAGS_NOBLOCK)), VERR_INVALID_PARAMETER);
+    int rc = RTOnce(&g_rtProcWinInitOnce, rtProcWinInitOnce, NULL);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Try find the process among the ones we've spawned, otherwise, attempt
+     * opening the specified process.
+     */
+    HANDLE hOpenedProc = NULL;
+    HANDLE hProcess = rtProcWinFindPid(Process);
+    if (hProcess == NULL)
+    {
+        hProcess = hOpenedProc = OpenProcess(PROCESS_QUERY_INFORMATION | SYNCHRONIZE, FALSE, Process);
+        if (hProcess == NULL)
+        {
+            DWORD dwErr = GetLastError();
+            if (dwErr == ERROR_INVALID_PARAMETER)
+                return VERR_PROCESS_NOT_FOUND;
+            return RTErrConvertFromWin32(dwErr);
+        }
+    }
+
+    /*
+     * Wait for it to terminate.
+     */
+    DWORD Millies = fFlags == RTPROCWAIT_FLAGS_BLOCK ? INFINITE : 0;
+    DWORD WaitRc = WaitForSingleObjectEx(hProcess, Millies, TRUE);
+    while (WaitRc == WAIT_IO_COMPLETION)
+        WaitRc = WaitForSingleObjectEx(hProcess, Millies, TRUE);
+    switch (WaitRc)
+    {
+        /*
+         * It has terminated.
+         */
+        case WAIT_OBJECT_0:
+        {
+            DWORD dwExitCode;
+            if (GetExitCodeProcess(hProcess, &dwExitCode))
+            {
+                /** @todo the exit code can be special statuses. */
+                if (pProcStatus)
+                {
+                    pProcStatus->enmReason = RTPROCEXITREASON_NORMAL;
+                    pProcStatus->iStatus = (int)dwExitCode;
+                }
+                if (hOpenedProc == NULL)
+                    rtProcWinRemovePid(Process);
+                rc = VINF_SUCCESS;
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+            break;
+        }
+
+        /*
+         * It hasn't terminated just yet.
+         */
+        case WAIT_TIMEOUT:
+            rc = VERR_PROCESS_RUNNING;
+            break;
+
+        /*
+         * Something went wrong...
+         */
+        case WAIT_FAILED:
+            rc = RTErrConvertFromWin32(GetLastError());
+            break;
+
+        case WAIT_ABANDONED:
+            AssertFailed();
+            rc = VERR_GENERAL_FAILURE;
+            break;
+
+        default:
+            AssertMsgFailed(("WaitRc=%RU32\n", WaitRc));
+            rc = VERR_GENERAL_FAILURE;
+            break;
+    }
+
+    if (hOpenedProc != NULL)
+        CloseHandle(hOpenedProc);
+    return rc;
+}
+
+
+RTR3DECL(int) RTProcWaitNoResume(RTPROCESS Process, unsigned fFlags, PRTPROCSTATUS pProcStatus)
+{
+    /** @todo this isn't quite right. */
+    return RTProcWait(Process, fFlags, pProcStatus);
+}
+
+
+RTR3DECL(int) RTProcTerminate(RTPROCESS Process)
+{
+    if (Process == NIL_RTPROCESS)
+        return VINF_SUCCESS;
+
+    int rc = RTOnce(&g_rtProcWinInitOnce, rtProcWinInitOnce, NULL);
+    AssertRCReturn(rc, rc);
+
+    /*
+     * Try find the process among the ones we've spawned, otherwise, attempt
+     * opening the specified process.
+     */
+    HANDLE hProcess = rtProcWinFindPid(Process);
+    if (hProcess != NULL)
+    {
+        if (!TerminateProcess(hProcess, 127))
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        hProcess = OpenProcess(PROCESS_TERMINATE, FALSE, Process);
+        if (hProcess != NULL)
+        {
+            BOOL  fRc   = TerminateProcess(hProcess, 127);
+            DWORD dwErr = GetLastError();
+            CloseHandle(hProcess);
+            if (!fRc)
+                rc = RTErrConvertFromWin32(dwErr);
+        }
+    }
+    return rc;
+}
+
+
+RTR3DECL(uint64_t) RTProcGetAffinityMask(void)
+{
+    DWORD_PTR dwProcessAffinityMask = 0xffffffff;
+    DWORD_PTR dwSystemAffinityMask;
+
+    BOOL fRc = GetProcessAffinityMask(GetCurrentProcess(), &dwProcessAffinityMask, &dwSystemAffinityMask);
+    Assert(fRc); NOREF(fRc);
+
+    return dwProcessAffinityMask;
+}
+
+
+RTR3DECL(int) RTProcQueryUsername(RTPROCESS hProcess, char *pszUser, size_t cbUser, size_t *pcbUser)
+{
+    AssertReturn(   (pszUser && cbUser > 0)
+                 || (!pszUser && !cbUser), VERR_INVALID_PARAMETER);
+    AssertReturn(pcbUser || pszUser, VERR_INVALID_PARAMETER);
+
+    int rc;
+    if (   hProcess == NIL_RTPROCESS
+        || hProcess == RTProcSelf())
+    {
+        RTUTF16 wszUsername[UNLEN + 1];
+        DWORD   cwcUsername = RT_ELEMENTS(wszUsername);
+        if (GetUserNameW(&wszUsername[0], &cwcUsername))
+        {
+            if (pszUser)
+            {
+                rc = RTUtf16ToUtf8Ex(wszUsername, cwcUsername, &pszUser, cbUser, pcbUser);
+                if (pcbUser)
+                    *pcbUser += 1;
+            }
+            else
+            {
+                *pcbUser = RTUtf16CalcUtf8Len(wszUsername) + 1;
+                rc = VERR_BUFFER_OVERFLOW;
+            }
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
+
+RTR3DECL(int) RTProcQueryUsernameA(RTPROCESS hProcess, char **ppszUser)
+{
+    AssertPtrReturn(ppszUser, VERR_INVALID_POINTER);
+    int rc;
+    if (   hProcess == NIL_RTPROCESS
+        || hProcess == RTProcSelf())
+    {
+        RTUTF16 wszUsername[UNLEN + 1];
+        DWORD   cwcUsername = RT_ELEMENTS(wszUsername);
+        if (GetUserNameW(&wszUsername[0], &cwcUsername))
+            rc = RTUtf16ToUtf8(wszUsername, ppszUser);
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+        rc = VERR_NOT_SUPPORTED;
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/rtProcInitExePath-win.cpp b/src/VBox/Runtime/r3/win/rtProcInitExePath-win.cpp
new file mode 100644
index 00000000..f0f478f6
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/rtProcInitExePath-win.cpp
@@ -0,0 +1,72 @@
+/* $Id: rtProcInitExePath-win.cpp $ */
+/** @file
+ * IPRT - rtProcInitName, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_PROCESS
+#include <iprt/win/windows.h>
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include <iprt/path.h>
+#include <iprt/param.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+#include "internal/process.h"
+
+
+DECLHIDDEN(int) rtProcInitExePath(char *pszPath, size_t cchPath)
+{
+    /*
+     * Query the image name from the dynamic linker, convert and return it.
+     */
+    WCHAR  wsz[RTPATH_MAX];
+    HMODULE hExe = GetModuleHandle(NULL);
+    if (GetModuleFileNameW(hExe, wsz, RTPATH_MAX))
+    {
+        int rc = RTUtf16ToUtf8Ex(wsz, RTSTR_MAX, &pszPath, cchPath, NULL);
+        AssertRCReturn(rc, rc);
+        return VINF_SUCCESS;
+    }
+
+    DWORD err = GetLastError();
+    int rc = RTErrConvertFromWin32(err);
+    AssertMsgFailed(("%Rrc %d\n", rc, err));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/sched-win.cpp b/src/VBox/Runtime/r3/win/sched-win.cpp
new file mode 100644
index 00000000..7b8397e0
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/sched-win.cpp
@@ -0,0 +1,333 @@
+/* $Id: sched-win.cpp $ */
+/** @file
+ * IPRT - Scheduling, Win32.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+/** @def WIN32_SCHED_ENABLED
+ * Enables the priority scheme. */
+#define WIN32_SCHED_ENABLED
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <iprt/win/windows.h>
+
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include "internal/sched.h"
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * Configuration of one priority.
+ */
+typedef struct
+{
+    /** The priority. */
+    RTPROCPRIORITY  enmPriority;
+    /** The name of this priority. */
+    const char     *pszName;
+    /** The Win32 process priority class. If ANY_PROCESS_PRIORITY_CLASS the
+     * process priority class is left unchanged. */
+    DWORD dwProcessPriorityClass;
+    /** Array scheduler attributes corresponding to each of the thread types. */
+    struct
+    {
+        /** For sanity include the array index. */
+        RTTHREADTYPE    enmType;
+        /** The Win32 thread priority. */
+        int             iThreadPriority;
+    } aTypes[RTTHREADTYPE_END];
+} PROCPRIORITY;
+
+/** Matches any process priority class. */
+#define ANY_PROCESS_PRIORITY_CLASS  (~0U)
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Array of static priority configurations.
+ */
+static const PROCPRIORITY g_aPriorities[] =
+{
+    {
+        RTPROCPRIORITY_FLAT, "Flat", ANY_PROCESS_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_NORMAL }
+        }
+    },
+    {
+        RTPROCPRIORITY_LOW, "Low - Below Normal", BELOW_NORMAL_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    },
+    {
+        RTPROCPRIORITY_LOW, "Low", ANY_PROCESS_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_NORMAL }
+        }
+    },
+    {
+        RTPROCPRIORITY_NORMAL, "Normal - Normal", NORMAL_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    },
+    {
+        RTPROCPRIORITY_NORMAL, "Normal", ANY_PROCESS_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    },
+    {
+        RTPROCPRIORITY_HIGH, "High - High", HIGH_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    },
+    {
+        RTPROCPRIORITY_HIGH, "High - Above Normal", ABOVE_NORMAL_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_LOWEST },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    },
+    {
+        RTPROCPRIORITY_HIGH, "High", ANY_PROCESS_PRIORITY_CLASS,
+        {
+            { RTTHREADTYPE_INVALID,                 ~0 },
+            { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_BELOW_NORMAL },
+            { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_NORMAL },
+            { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_ABOVE_NORMAL },
+            { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_IO,                      THREAD_PRIORITY_HIGHEST },
+            { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+        }
+    }
+};
+
+/**
+ * The dynamic default priority configuration.
+ *
+ * This can be recalulated at runtime depending on what the
+ * system allow us to do. Presently we don't do this as it's
+ * generally not a bit issue on Win32 hosts.
+ */
+static PROCPRIORITY g_aDefaultPriority =
+{
+    RTPROCPRIORITY_LOW, "Default", ANY_PROCESS_PRIORITY_CLASS,
+    {
+        { RTTHREADTYPE_INVALID,                 ~0 },
+        { RTTHREADTYPE_INFREQUENT_POLLER,       THREAD_PRIORITY_LOWEST },
+        { RTTHREADTYPE_MAIN_HEAVY_WORKER,       THREAD_PRIORITY_BELOW_NORMAL },
+        { RTTHREADTYPE_EMULATION,               THREAD_PRIORITY_NORMAL },
+        { RTTHREADTYPE_DEFAULT,                 THREAD_PRIORITY_NORMAL },
+        { RTTHREADTYPE_GUI,                     THREAD_PRIORITY_NORMAL },
+        { RTTHREADTYPE_MAIN_WORKER,             THREAD_PRIORITY_NORMAL },
+        { RTTHREADTYPE_VRDP_IO,                 THREAD_PRIORITY_NORMAL },
+        { RTTHREADTYPE_DEBUGGER,                THREAD_PRIORITY_ABOVE_NORMAL },
+        { RTTHREADTYPE_MSG_PUMP,                THREAD_PRIORITY_ABOVE_NORMAL },
+        { RTTHREADTYPE_IO,                      THREAD_PRIORITY_HIGHEST },
+        { RTTHREADTYPE_TIMER,                   THREAD_PRIORITY_HIGHEST }
+    }
+};
+
+
+/** Pointer to the current priority configuration. */
+static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
+
+
+/**
+ * Calculate the scheduling properties for all the threads in the default
+ * process priority, assuming the current thread have the type enmType.
+ *
+ * @returns iprt status code.
+ * @param   enmType     The thread type to be assumed for the current thread.
+ */
+DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END); RT_NOREF_PV(enmType);
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
+{
+    Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST); RT_NOREF_PV(enmPriority);
+
+    if (enmPriority == RTPROCPRIORITY_DEFAULT)
+    {
+        g_pProcessPriority = &g_aDefaultPriority;
+        return VINF_SUCCESS;
+    }
+
+    for (size_t i = 0; i < RT_ELEMENTS(g_aPriorities); i++)
+        if (   g_aPriorities[i].enmPriority == enmPriority
+            && g_aPriorities[i].dwProcessPriorityClass == ANY_PROCESS_PRIORITY_CLASS)
+        {
+            g_pProcessPriority = &g_aPriorities[i];
+            return VINF_SUCCESS;
+        }
+
+    AssertFailedReturn(VERR_INTERNAL_ERROR);
+}
+
+
+/**
+ * Gets the win32 thread handle.
+ *
+ * @returns Valid win32 handle for the specified thread.
+ * @param   pThread     The thread.
+ */
+DECLINLINE(HANDLE) rtThreadNativeGetHandle(PRTTHREADINT pThread)
+{
+    if ((uintptr_t)pThread->Core.Key == GetCurrentThreadId())
+        return GetCurrentThread();
+    return (HANDLE)pThread->hThread;
+}
+
+
+DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
+{
+    Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
+    AssertMsg(g_pProcessPriority && g_pProcessPriority->aTypes[enmType].enmType == enmType,
+              ("enmType=%d entry=%d\n", enmType, g_pProcessPriority->aTypes[enmType].enmType));
+
+#ifdef WIN32_SCHED_ENABLED
+    HANDLE hThread = rtThreadNativeGetHandle(pThread);
+    if (   hThread == NULL /* No handle for alien threads. */
+        || SetThreadPriority(hThread, g_pProcessPriority->aTypes[enmType].iThreadPriority))
+        return VINF_SUCCESS;
+
+    DWORD dwLastError = GetLastError();
+    int rc = RTErrConvertFromWin32(dwLastError);
+    AssertMsgFailed(("SetThreadPriority(%p, %d) failed, dwLastError=%d rc=%Rrc\n",
+                     rtThreadNativeGetHandle(pThread), g_pProcessPriority->aTypes[enmType].iThreadPriority, dwLastError, rc));
+    return rc;
+#else
+    return VINF_SUCCESS;
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/win/semevent-win.cpp b/src/VBox/Runtime/r3/win/semevent-win.cpp
new file mode 100644
index 00000000..be086941
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/semevent-win.cpp
@@ -0,0 +1,315 @@
+/* $Id: semevent-win.cpp $ */
+/** @file
+ * IPRT - Event Semaphore, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SEMAPHORE
+#include <iprt/win/windows.h>
+
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/thread.h>
+#include "internal/magics.h"
+#include "internal/mem.h"
+#include "internal/strict.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+struct RTSEMEVENTINTERNAL
+{
+    /** Magic value (RTSEMEVENT_MAGIC). */
+    uint32_t            u32Magic;
+    /** The event handle. */
+    HANDLE              hev;
+#ifdef RTSEMEVENT_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+    /** The creation flags. */
+    uint32_t            fFlags;
+};
+
+
+
+RTDECL(int)  RTSemEventCreate(PRTSEMEVENT phEventSem)
+{
+    return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
+    Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
+
+    struct RTSEMEVENTINTERNAL *pThis;
+    if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        pThis = (struct RTSEMEVENTINTERNAL *)RTMemAlloc(sizeof(*pThis));
+    else
+        pThis = (struct RTSEMEVENTINTERNAL *)rtMemBaseAlloc(sizeof(*pThis));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+
+    /*
+     * Create the semaphore.
+     * (Auto reset, not signaled, private event object.)
+     */
+    pThis->hev = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (pThis->hev != NULL) /* not INVALID_HANDLE_VALUE */
+    {
+        pThis->u32Magic = RTSEMEVENT_MAGIC;
+        pThis->fFlags   = fFlags;
+#ifdef RTSEMEVENT_STRICT
+        if (!pszNameFmt)
+        {
+            static uint32_t volatile s_iSemEventAnon = 0;
+            RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                         true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                         "RTSemEvent-%u", ASMAtomicIncU32(&s_iSemEventAnon) - 1);
+        }
+        else
+        {
+            va_list va;
+            va_start(va, pszNameFmt);
+            RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                          true /*fSignaller*/, !(fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL),
+                                          pszNameFmt, va);
+            va_end(va);
+        }
+        pThis->fEverHadSignallers = false;
+#else
+        RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
+#endif
+
+        *phEventSem = pThis;
+        return VINF_SUCCESS;
+    }
+
+    DWORD dwErr = GetLastError();
+    if (!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+        RTMemFree(pThis);
+    else
+        rtMemBaseFree(pThis);
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+RTDECL(int)  RTSemEventDestroy(RTSEMEVENT hEventSem)
+{
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    if (pThis == NIL_RTSEMEVENT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the handle and close the semaphore.
+     */
+    int rc = VINF_SUCCESS;
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMEVENT_MAGIC, RTSEMEVENT_MAGIC), VERR_INVALID_HANDLE);
+    if (CloseHandle(pThis->hev))
+    {
+#ifdef RTSEMEVENT_STRICT
+        RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+        if (!(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK))
+            RTMemFree(pThis);
+        else
+            rtMemBaseFree(pThis);
+    }
+    else
+    {
+        DWORD dwErr = GetLastError();
+        rc = RTErrConvertFromWin32(dwErr);
+        AssertMsgFailed(("Destroy hEventSem %p failed, lasterr=%u (%Rrc)\n", pThis, dwErr, rc));
+        /* Leak it. */
+    }
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENT_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    /*
+     * Signal the object.
+     */
+    if (SetEvent(pThis->hev))
+        return VINF_SUCCESS;
+    DWORD dwErr = GetLastError();
+    AssertMsgFailed(("Signaling hEventSem %p failed, lasterr=%d\n", pThis, dwErr));
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+/** Goto avoidance. */
+DECL_FORCE_INLINE(int) rtSemEventWaitHandleStatus(struct RTSEMEVENTINTERNAL *pThis, DWORD rc)
+{
+    switch (rc)
+    {
+        case WAIT_OBJECT_0:         return VINF_SUCCESS;
+        case WAIT_TIMEOUT:          return VERR_TIMEOUT;
+        case WAIT_IO_COMPLETION:    return VERR_INTERRUPTED;
+        case WAIT_ABANDONED:        return VERR_SEM_OWNER_DIED;
+        default:
+            AssertMsgFailed(("%u\n", rc));
+        case WAIT_FAILED:
+        {
+            int rc2 = RTErrConvertFromWin32(GetLastError());
+            AssertMsgFailed(("Wait on hEventSem %p failed, rc=%d lasterr=%d\n", pThis, rc, GetLastError()));
+            if (rc2)
+                return rc2;
+
+            AssertMsgFailed(("WaitForSingleObject(event) -> rc=%d while converted lasterr=%d\n", rc, rc2));
+            RT_NOREF_PV(pThis);
+            return VERR_INTERNAL_ERROR;
+        }
+    }
+}
+
+
+#undef RTSemEventWaitNoResume
+RTDECL(int)   RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Wait for condition.
+     */
+#ifdef RTSEMEVENT_STRICT
+    RTTHREAD hThreadSelf = !(pThis->fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)
+                         ? RTThreadSelfAutoAdopt()
+                         : RTThreadSelf();
+    if (pThis->fEverHadSignallers)
+    {
+        DWORD rc = WaitForSingleObjectEx(pThis->hev,
+                                         0 /*Timeout*/,
+                                         TRUE /*fAlertable*/);
+        if (rc != WAIT_TIMEOUT || cMillies == 0)
+            return rtSemEventWaitHandleStatus(pThis, rc);
+        int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, NULL /*pSrcPos*/, false,
+                                                        cMillies, RTTHREADSTATE_EVENT, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+    RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT, true);
+    DWORD rc = WaitForSingleObjectEx(pThis->hev,
+                                     cMillies == RT_INDEFINITE_WAIT ? INFINITE : cMillies,
+                                     TRUE /*fAlertable*/);
+    RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT);
+    return rtSemEventWaitHandleStatus(pThis, rc);
+}
+
+
+RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENT_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENT_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTINTERNAL *pThis = hEventSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENT_MAGIC);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF_PV(hEventSem); RT_NOREF_PV(hThread);
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/win/semeventmulti-win.cpp b/src/VBox/Runtime/r3/win/semeventmulti-win.cpp
new file mode 100644
index 00000000..ed37f656
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/semeventmulti-win.cpp
@@ -0,0 +1,389 @@
+/* $Id: semeventmulti-win.cpp $ */
+/** @file
+ * IPRT - Multiple Release Event Semaphore, Windows.
+ *
+ * @remarks This file is identical to semevent-win.cpp except for the 2nd
+ *          CreateEvent parameter, the reset function and the "Multi" infix.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SEMAPHORE
+#include <iprt/win/windows.h>
+
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+struct RTSEMEVENTMULTIINTERNAL
+{
+    /** Magic value (RTSEMEVENTMULTI_MAGIC). */
+    uint32_t            u32Magic;
+    /** The event handle. */
+    HANDLE              hev;
+#ifdef RTSEMEVENT_STRICT
+    /** Signallers. */
+    RTLOCKVALRECSHRD    Signallers;
+    /** Indicates that lock validation should be performed. */
+    bool volatile       fEverHadSignallers;
+#endif
+};
+
+
+
+RTDECL(int)  RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem)
+{
+    return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
+}
+
+
+RTDECL(int)  RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
+                                     const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(*pThis));
+    if (!pThis)
+        return VERR_NO_MEMORY;
+
+    /*
+     * Create the semaphore.
+     * (Manual reset, not signaled, private event object.)
+     */
+    pThis->hev = CreateEvent(NULL, TRUE, FALSE, NULL);
+    if (pThis->hev != NULL) /* not INVALID_HANDLE_VALUE */
+    {
+        pThis->u32Magic = RTSEMEVENTMULTI_MAGIC;
+#ifdef RTSEMEVENT_STRICT
+        if (!pszNameFmt)
+        {
+            static uint32_t volatile s_iSemEventMultiAnon = 0;
+            RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                         true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                         "RTSemEventMulti-%u", ASMAtomicIncU32(&s_iSemEventMultiAnon) - 1);
+        }
+        else
+        {
+            va_list va;
+            va_start(va, pszNameFmt);
+            RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis,
+                                          true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL),
+                                          pszNameFmt, va);
+            va_end(va);
+        }
+        pThis->fEverHadSignallers = false;
+#else
+        RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
+#endif
+
+        *phEventMultiSem = pThis;
+        return VINF_SUCCESS;
+    }
+
+    DWORD dwErr = GetLastError();
+    RTMemFree(pThis);
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+RTDECL(int)  RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
+{
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    if (pThis == NIL_RTSEMEVENT)        /* don't bitch */
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Invalidate the handle and close the semaphore.
+     */
+    int rc = VINF_SUCCESS;
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, ~RTSEMEVENTMULTI_MAGIC, RTSEMEVENTMULTI_MAGIC), VERR_INVALID_HANDLE);
+    if (CloseHandle(pThis->hev))
+    {
+#ifdef RTSEMEVENT_STRICT
+        RTLockValidatorRecSharedDelete(&pThis->Signallers);
+#endif
+        RTMemFree(pThis);
+    }
+    else
+    {
+        DWORD dwErr = GetLastError();
+        rc = RTErrConvertFromWin32(dwErr);
+        AssertMsgFailed(("Destroy hEventMultiSem %p failed, lasterr=%u (%Rrc)\n", pThis, dwErr, rc));
+        /* Leak it. */
+    }
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+
+#ifdef RTSEMEVENT_STRICT
+    if (pThis->fEverHadSignallers)
+    {
+        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#endif
+
+    /*
+     * Signal the object.
+     */
+    if (SetEvent(pThis->hev))
+        return VINF_SUCCESS;
+    DWORD dwErr = GetLastError();
+    AssertMsgFailed(("Signaling hEventMultiSem %p failed, lasterr=%d\n", pThis, dwErr));
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+RTDECL(int)  RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Reset the object.
+     */
+    if (ResetEvent(pThis->hev))
+        return VINF_SUCCESS;
+    DWORD dwErr = GetLastError();
+    AssertMsgFailed(("Resetting hEventMultiSem %p failed, lasterr=%d\n", pThis, dwErr));
+    return RTErrConvertFromWin32(dwErr);
+}
+
+
+/** Goto avoidance. */
+DECL_FORCE_INLINE(int)
+rtSemEventWaitHandleStatus(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, DWORD rc)
+{
+    switch (rc)
+    {
+        case WAIT_OBJECT_0:         return VINF_SUCCESS;
+        case WAIT_TIMEOUT:          return VERR_TIMEOUT;
+        case WAIT_IO_COMPLETION:    return fFlags & RTSEMWAIT_FLAGS_RESUME ? VERR_TIMEOUT : VERR_INTERRUPTED;
+        case WAIT_ABANDONED:        return VERR_SEM_OWNER_DIED;
+        default:
+            AssertMsgFailed(("%u\n", rc));
+        case WAIT_FAILED:
+        {
+            int rc2 = RTErrConvertFromWin32(GetLastError());
+            AssertMsgFailed(("Wait on hEventMultiSem %p failed, rc=%d lasterr=%d\n", pThis, rc, GetLastError()));
+            if (rc2)
+                return rc2;
+
+            AssertMsgFailed(("WaitForSingleObject(event) -> rc=%d while converted lasterr=%d\n", rc, rc2));
+            RT_NOREF_PV(pThis);
+            return VERR_INTERNAL_ERROR;
+        }
+    }
+}
+
+
+DECLINLINE(int) rtSemEventMultiWinWait(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
+                                       PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate input.
+     */
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
+
+    /*
+     * Convert the timeout to a millisecond count.
+     */
+    uint64_t uAbsDeadline;
+    DWORD    dwMsTimeout;
+    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
+    {
+        dwMsTimeout  = INFINITE;
+        uAbsDeadline = UINT64_MAX;
+    }
+    else
+    {
+        if (fFlags & RTSEMWAIT_FLAGS_NANOSECS)
+            uTimeout = uTimeout < UINT64_MAX - UINT32_C(1000000) / 2
+                     ? (uTimeout + UINT32_C(1000000) / 2) / UINT32_C(1000000)
+                     : UINT64_MAX / UINT32_C(1000000);
+        if (fFlags & RTSEMWAIT_FLAGS_ABSOLUTE)
+        {
+            uAbsDeadline = uTimeout;
+            uint64_t u64Now = RTTimeSystemMilliTS();
+            if (u64Now < uTimeout)
+                uTimeout -= u64Now;
+            else
+                uTimeout = 0;
+        }
+        else if (fFlags & RTSEMWAIT_FLAGS_RESUME)
+            uAbsDeadline = RTTimeSystemMilliTS() + uTimeout;
+        else
+            uAbsDeadline = UINT64_MAX;
+
+        dwMsTimeout = uTimeout < UINT32_MAX
+                    ? (DWORD)uTimeout
+                    : INFINITE;
+    }
+
+    /*
+     * Do the wait.
+     */
+    DWORD rc;
+#ifdef RTSEMEVENT_STRICT
+    RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+    if (pThis->fEverHadSignallers)
+    {
+        do
+            rc = WaitForSingleObjectEx(pThis->hev, 0 /*Timeout*/, TRUE /*fAlertable*/);
+        while (rc == WAIT_IO_COMPLETION && (fFlags & RTSEMWAIT_FLAGS_RESUME));
+        if (rc != WAIT_TIMEOUT || dwMsTimeout == 0)
+            return rtSemEventWaitHandleStatus(pThis, fFlags, rc);
+        int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
+                                                        dwMsTimeout, RTTHREADSTATE_EVENT_MULTI, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+    }
+#else
+    RTTHREAD hThreadSelf = RTThreadSelf();
+    RT_NOREF_PV(pSrcPos);
+#endif
+    RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
+    rc = WaitForSingleObjectEx(pThis->hev, dwMsTimeout, TRUE /*fAlertable*/);
+    if (rc == WAIT_IO_COMPLETION && (fFlags & RTSEMWAIT_FLAGS_RESUME))
+    {
+        while (   rc == WAIT_IO_COMPLETION
+               && RTTimeSystemMilliTS() < uAbsDeadline)
+            rc = WaitForSingleObjectEx(pThis->hev, dwMsTimeout, TRUE /*fAlertable*/);
+
+    }
+    RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
+    return rtSemEventWaitHandleStatus(pThis, fFlags, rc);
+}
+
+
+
+#undef RTSemEventMultiWaitEx
+RTDECL(int)  RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout)
+{
+#ifndef RTSEMEVENT_STRICT
+    return rtSemEventMultiWinWait(hEventMultiSem, fFlags, uTimeout, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemEventMultiWinWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+#endif
+}
+
+
+RTDECL(int)  RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
+                                        RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemEventMultiWinWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
+}
+
+
+
+RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
+    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
+
+RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
+{
+#ifdef RTSEMEVENT_STRICT
+    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
+    AssertPtrReturnVoid(pThis);
+    AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC);
+
+    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
+#else
+    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
+#endif
+}
+
diff --git a/src/VBox/Runtime/r3/win/semmutex-win.cpp b/src/VBox/Runtime/r3/win/semmutex-win.cpp
new file mode 100644
index 00000000..34aa8bc5
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/semmutex-win.cpp
@@ -0,0 +1,356 @@
+/* $Id: semmutex-win.cpp $ */
+/** @file
+ * IPRT - Mutex Semaphores, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SEMAPHORE
+#include <iprt/win/windows.h>
+
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/thread.h>
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Posix internal representation of a Mutex semaphore. */
+struct RTSEMMUTEXINTERNAL
+{
+    /** Magic value (RTSEMMUTEX_MAGIC). */
+    uint32_t                u32Magic;
+    /** Recursion count. */
+    uint32_t volatile       cRecursions;
+    /** The owner thread. */
+    RTNATIVETHREAD volatile hNativeOwner;
+    /** The mutex handle. */
+    HANDLE                  hMtx;
+#ifdef RTSEMMUTEX_STRICT
+    /** Lock validator record associated with this mutex. */
+    RTLOCKVALRECEXCL        ValidatorRec;
+#endif
+};
+
+
+
+#undef RTSemMutexCreate
+RTDECL(int)  RTSemMutexCreate(PRTSEMMUTEX phMutexSem)
+{
+    return RTSemMutexCreateEx(phMutexSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+}
+
+
+RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags,
+                               RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...)
+{
+    AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER);
+
+    /*
+     * Create the semaphore.
+     */
+    int rc;
+    HANDLE hMtx = CreateMutex(NULL, FALSE, NULL);
+    if (hMtx)
+    {
+        RTSEMMUTEXINTERNAL *pThis = (RTSEMMUTEXINTERNAL *)RTMemAlloc(sizeof(*pThis));
+        if (pThis)
+        {
+            pThis->u32Magic     = RTSEMMUTEX_MAGIC;
+            pThis->hMtx         = hMtx;
+            pThis->hNativeOwner = NIL_RTNATIVETHREAD;
+            pThis->cRecursions  = 0;
+#ifdef RTSEMMUTEX_STRICT
+            if (!pszNameFmt)
+            {
+                static uint32_t volatile s_iMutexAnon = 0;
+                RTLockValidatorRecExclInit(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                           !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL),
+                                           "RTSemMutex-%u", ASMAtomicIncU32(&s_iMutexAnon) - 1);
+            }
+            else
+            {
+                va_list va;
+                va_start(va, pszNameFmt);
+                RTLockValidatorRecExclInitV(&pThis->ValidatorRec, hClass, uSubClass, pThis,
+                                            !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), pszNameFmt, va);
+                va_end(va);
+            }
+#else
+            RT_NOREF_PV(hClass); RT_NOREF_PV(uSubClass); RT_NOREF_PV(pszNameFmt);
+#endif
+            *phMutexSem = pThis;
+            return VINF_SUCCESS;
+        }
+
+        rc = VERR_NO_MEMORY;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+    return rc;
+}
+
+
+RTDECL(int)  RTSemMutexDestroy(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    if (pThis == NIL_RTSEMMUTEX)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Close semaphore handle.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD, RTSEMMUTEX_MAGIC), VERR_INVALID_HANDLE);
+    HANDLE hMtx = pThis->hMtx;
+    ASMAtomicWritePtr(&pThis->hMtx, INVALID_HANDLE_VALUE);
+
+    int rc = VINF_SUCCESS;
+    if (!CloseHandle(hMtx))
+    {
+        rc = RTErrConvertFromWin32(GetLastError());
+        AssertMsgFailed(("%p rc=%d lasterr=%d\n", pThis->hMtx, rc, GetLastError()));
+    }
+
+#ifdef RTSEMMUTEX_STRICT
+    RTLockValidatorRecExclDelete(&pThis->ValidatorRec);
+#endif
+    RTMemFree(pThis);
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass)
+{
+#ifdef RTSEMMUTEX_STRICT
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID);
+
+    return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass);
+#else
+    RT_NOREF_PV(hMutexSem); RT_NOREF_PV(uSubClass);
+    return RTLOCKVAL_SUB_CLASS_INVALID;
+#endif
+}
+
+
+/**
+ * Internal worker for RTSemMutexRequestNoResume and it's debug companion.
+ *
+ * @returns Same as RTSEmMutexRequestNoResume
+ * @param   hMutexSem            The mutex handle.
+ * @param   cMillies            The number of milliseconds to wait.
+ * @param   pSrcPos             The source position of the caller.
+ */
+DECL_FORCE_INLINE(int) rtSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Check for recursive entry.
+     */
+    RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
+    RTNATIVETHREAD hNativeOwner;
+    ASMAtomicReadHandle(&pThis->hNativeOwner, &hNativeOwner);
+    if (hNativeOwner == hNativeSelf)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorRec, pSrcPos);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        ASMAtomicIncU32(&pThis->cRecursions);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Lock mutex semaphore.
+     */
+    RTTHREAD        hThreadSelf = NIL_RTTHREAD;
+    if (cMillies > 0)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        hThreadSelf = RTThreadSelfAutoAdopt();
+        int rc9 = RTLockValidatorRecExclCheckOrderAndBlocking(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true,
+                                                              cMillies, RTTHREADSTATE_MUTEX, true);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#else
+        hThreadSelf = RTThreadSelf();
+        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_MUTEX, true);
+        RT_NOREF_PV(pSrcPos);
+#endif
+    }
+    DWORD rc = WaitForSingleObjectEx(pThis->hMtx,
+                                     cMillies == RT_INDEFINITE_WAIT ? INFINITE : cMillies,
+                                     TRUE /*fAlertable*/);
+    RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX);
+    switch (rc)
+    {
+        case WAIT_OBJECT_0:
+#ifdef RTSEMMUTEX_STRICT
+            RTLockValidatorRecExclSetOwner(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true);
+#endif
+            ASMAtomicWriteHandle(&pThis->hNativeOwner, hNativeSelf);
+            ASMAtomicWriteU32(&pThis->cRecursions, 1);
+            return VINF_SUCCESS;
+
+        case WAIT_TIMEOUT:          return VERR_TIMEOUT;
+        case WAIT_IO_COMPLETION:    return VERR_INTERRUPTED;
+        case WAIT_ABANDONED:        return VERR_SEM_OWNER_DIED;
+        default:
+            AssertMsgFailed(("%u\n",  rc));
+        case WAIT_FAILED:
+        {
+            int rc2 = RTErrConvertFromWin32(GetLastError());
+            AssertMsgFailed(("Wait on hMutexSem %p failed, rc=%d lasterr=%d\n", hMutexSem, rc, GetLastError()));
+            if (rc2 != VINF_SUCCESS)
+                return rc2;
+
+            AssertMsgFailed(("WaitForSingleObject(event) -> rc=%d while converted lasterr=%d\n", rc, rc2));
+            return VERR_INTERNAL_ERROR;
+        }
+    }
+}
+
+
+#undef RTSemMutexRequestNoResume
+RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMMUTEX_STRICT
+    return rtSemMutexRequestNoResume(hMutexSem, cMillies, NULL);
+#else
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+    return rtSemMutexRequestNoResume(hMutexSem, cMillies, &SrcPos);
+#endif
+}
+
+
+RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+    return rtSemMutexRequestNoResume(hMutexSem, cMillies, &SrcPos);
+}
+
+
+RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Check ownership and recursions.
+     */
+    RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
+    RTNATIVETHREAD hNativeOwner;
+    ASMAtomicReadHandle(&pThis->hNativeOwner, &hNativeOwner);
+    if (RT_UNLIKELY(hNativeOwner != hNativeSelf))
+    {
+        AssertMsgFailed(("Not owner of mutex %p!! hNativeSelf=%RTntrd Owner=%RTntrd cRecursions=%d\n",
+                         pThis, hNativeSelf, hNativeOwner, pThis->cRecursions));
+        return VERR_NOT_OWNER;
+    }
+    if (pThis->cRecursions > 1)
+    {
+#ifdef RTSEMMUTEX_STRICT
+        int rc9 = RTLockValidatorRecExclUnwind(&pThis->ValidatorRec);
+        if (RT_FAILURE(rc9))
+            return rc9;
+#endif
+        ASMAtomicDecU32(&pThis->cRecursions);
+        return VINF_SUCCESS;
+    }
+
+    /*
+     * Unlock mutex semaphore.
+     */
+#ifdef RTSEMMUTEX_STRICT
+    int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorRec, false);
+    if (RT_FAILURE(rc9))
+        return rc9;
+#endif
+    ASMAtomicWriteU32(&pThis->cRecursions, 0);
+    ASMAtomicWriteHandle(&pThis->hNativeOwner, NIL_RTNATIVETHREAD);
+
+    if (ReleaseMutex(pThis->hMtx))
+        return VINF_SUCCESS;
+
+    int rc = RTErrConvertFromWin32(GetLastError());
+    AssertMsgFailed(("%p/%p, rc=%Rrc lasterr=%d\n", pThis, pThis->hMtx, rc, GetLastError()));
+    return rc;
+}
+
+
+RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem)
+{
+    /*
+     * Validate.
+     */
+    RTSEMMUTEXINTERNAL *pThis = hMutexSem;
+    AssertPtrReturn(pThis, false);
+    AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, false);
+
+    RTNATIVETHREAD hNativeOwner;
+    ASMAtomicReadHandle(&pThis->hNativeOwner, &hNativeOwner);
+    return hNativeOwner != NIL_RTNATIVETHREAD;
+}
+
diff --git a/src/VBox/Runtime/r3/win/serialport-win.cpp b/src/VBox/Runtime/r3/win/serialport-win.cpp
new file mode 100644
index 00000000..0f6f04c2
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/serialport-win.cpp
@@ -0,0 +1,1056 @@
+/* $Id: serialport-win.cpp $ */
+/** @file
+ * IPRT - Serial Port API, Windows Implementation.
+ */
+
+/*
+ * Copyright (C) 2017-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/serialport.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/errcore.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/thread.h>
+#include <iprt/time.h>
+#include "internal/magics.h"
+
+#include <iprt/win/windows.h>
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Internal serial port state.
+ */
+typedef struct RTSERIALPORTINTERNAL
+{
+    /** Magic value (RTSERIALPORT_MAGIC). */
+    uint32_t            u32Magic;
+    /** Flags given while opening the serial port. */
+    uint32_t            fOpenFlags;
+    /** The device handle. */
+    HANDLE              hDev;
+    /** The overlapped write structure. */
+    OVERLAPPED          OverlappedWrite;
+    /** The overlapped read structure. */
+    OVERLAPPED          OverlappedRead;
+    /** The overlapped I/O structure when waiting on events. */
+    OVERLAPPED          OverlappedEvt;
+    /** The event handle to wait on for the overlapped event operations of the device. */
+    HANDLE              hEvtDev;
+    /** The event handle to wait on for the overlapped write operations of the device. */
+    HANDLE              hEvtWrite;
+    /** The event handle to wait on for the overlapped read operations of the device. */
+    HANDLE              hEvtRead;
+    /** The event handle to wait on for waking up waiting threads externally. */
+    HANDLE              hEvtIntr;
+    /** Events currently waited for. */
+    uint32_t            fEvtMask;
+    /** Event mask as received by WaitCommEvent(). */
+    DWORD               dwEventMask;
+    /** Flag whether a write is currently pending. */
+    bool                fWritePending;
+    /** Event query pending. */
+    bool                fEvtQueryPending;
+    /** Bounce buffer for writes. */
+    uint8_t            *pbBounceBuf;
+    /** Amount of used buffer space. */
+    size_t              cbBounceBufUsed;
+    /** Amount of allocated buffer space. */
+    size_t              cbBounceBufAlloc;
+    /** The current active port config. */
+    DCB                 PortCfg;
+} RTSERIALPORTINTERNAL;
+/** Pointer to the internal serial port state. */
+typedef RTSERIALPORTINTERNAL *PRTSERIALPORTINTERNAL;
+
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** The pipe buffer size we prefer. */
+#define RTSERIALPORT_NT_SIZE      _32K
+
+
+
+/*********************************************************************************************************************************
+*   Global variables                                                                                                             *
+*********************************************************************************************************************************/
+
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Updatest the current event mask to wait for.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ * @param   fEvtMask                The new event mask to change to.
+ */
+static int rtSerialPortWinUpdateEvtMask(PRTSERIALPORTINTERNAL pThis, uint32_t fEvtMask)
+{
+    DWORD dwEvtMask = EV_ERR;
+
+    if (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX)
+        dwEvtMask |= EV_RXCHAR;
+    if (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX)
+        dwEvtMask |= EV_TXEMPTY;
+    if (fEvtMask & RTSERIALPORT_EVT_F_BREAK_DETECTED)
+        dwEvtMask |= EV_BREAK;
+    if (fEvtMask & RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED)
+        dwEvtMask |= EV_CTS | EV_DSR | EV_RING | EV_RLSD;
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommMask(pThis->hDev, dwEvtMask))
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+        pThis->fEvtMask = fEvtMask;
+
+    return rc;
+}
+
+
+/**
+ * Tries to set the default config on the given serial port.
+ *
+ * @returns IPRT status code.
+ * @param   pThis                   The internal serial port instance data.
+ */
+static int rtSerialPortSetDefaultCfg(PRTSERIALPORTINTERNAL pThis)
+{
+    if (!PurgeComm(pThis->hDev, PURGE_RXABORT | PURGE_RXCLEAR | PURGE_TXABORT | PURGE_TXCLEAR))
+        return RTErrConvertFromWin32(GetLastError());
+
+    pThis->PortCfg.DCBlength = sizeof(pThis->PortCfg);
+    if (!GetCommState(pThis->hDev, &pThis->PortCfg))
+        return RTErrConvertFromWin32(GetLastError());
+
+    pThis->PortCfg.BaudRate          = CBR_9600;
+    pThis->PortCfg.fBinary           = TRUE;
+    pThis->PortCfg.fParity           = TRUE;
+    pThis->PortCfg.fDtrControl       = DTR_CONTROL_DISABLE;
+    pThis->PortCfg.ByteSize          = 8;
+    pThis->PortCfg.Parity            = NOPARITY;
+    pThis->PortCfg.fOutxCtsFlow      = FALSE;
+    pThis->PortCfg.fOutxDsrFlow      = FALSE;
+    pThis->PortCfg.fDsrSensitivity   = FALSE;
+    pThis->PortCfg.fTXContinueOnXoff = TRUE;
+    pThis->PortCfg.fOutX             = FALSE;
+    pThis->PortCfg.fInX              = FALSE;
+    pThis->PortCfg.fErrorChar        = FALSE;
+    pThis->PortCfg.fNull             = FALSE;
+    pThis->PortCfg.fRtsControl       = RTS_CONTROL_DISABLE;
+    pThis->PortCfg.fAbortOnError     = FALSE;
+    pThis->PortCfg.wReserved         = 0;
+    pThis->PortCfg.XonLim            = 5;
+    pThis->PortCfg.XoffLim           = 5;
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommState(pThis->hDev, &pThis->PortCfg))
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Set timeouts for non blocking mode.
+         * See https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_commtimeouts .
+         */
+        COMMTIMEOUTS ComTimeouts;
+        RT_ZERO(ComTimeouts);
+        ComTimeouts.ReadIntervalTimeout = MAXDWORD;
+        if (!SetCommTimeouts(pThis->hDev, &ComTimeouts))
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+
+    return rc;
+}
+
+
+/**
+ * Common worker for handling I/O completion.
+ *
+ * This is used by RTSerialPortClose, RTSerialPortWrite and RTPipeSerialPortNB.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ */
+static int rtSerialPortWriteCheckCompletion(PRTSERIALPORTINTERNAL pThis)
+{
+    int rc = VINF_SUCCESS;
+    DWORD dwRc = WaitForSingleObject(pThis->OverlappedWrite.hEvent, 0);
+    if (dwRc == WAIT_OBJECT_0)
+    {
+        DWORD cbWritten = 0;
+        if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedWrite, &cbWritten, TRUE))
+        {
+            for (;;)
+            {
+                if (cbWritten >= pThis->cbBounceBufUsed)
+                {
+                    pThis->fWritePending = false;
+                    rc = VINF_SUCCESS;
+                    break;
+                }
+
+                /* resubmit the remainder of the buffer - can this actually happen? */
+                memmove(&pThis->pbBounceBuf[0], &pThis->pbBounceBuf[cbWritten], pThis->cbBounceBufUsed - cbWritten);
+                rc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(rc == TRUE);
+                if (!WriteFile(pThis->hDev, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                               &cbWritten, &pThis->OverlappedWrite))
+                {
+                    if (GetLastError() == ERROR_IO_PENDING)
+                        rc = VINF_TRY_AGAIN;
+                    else
+                    {
+                        pThis->fWritePending = false;
+                        rc = RTErrConvertFromWin32(GetLastError());
+                    }
+                    break;
+                }
+                Assert(cbWritten > 0);
+            }
+        }
+        else
+        {
+            pThis->fWritePending = false;
+            rc = RTErrConvertFromWin32(GetLastError());
+        }
+    }
+    else if (dwRc == WAIT_TIMEOUT)
+        rc = VINF_TRY_AGAIN;
+    else
+    {
+        pThis->fWritePending = false;
+        if (dwRc == WAIT_ABANDONED)
+            rc = VERR_INVALID_HANDLE;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+    return rc;
+}
+
+
+/**
+ * Processes the received Windows comm events and converts them to our format.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ * @param   dwEventMask         Event mask received.
+ * @param   pfEvtsRecv          Where to store the converted events.
+ */
+static int rtSerialPortEvtFlagsProcess(PRTSERIALPORTINTERNAL pThis, DWORD dwEventMask, uint32_t *pfEvtsRecv)
+{
+    int rc = VINF_SUCCESS;
+
+    if (dwEventMask & EV_RXCHAR)
+        *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_RX;
+    if (dwEventMask & EV_TXEMPTY)
+    {
+        if (pThis->fWritePending)
+        {
+            rc = rtSerialPortWriteCheckCompletion(pThis);
+            if (rc == VINF_SUCCESS)
+                *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+            else
+                rc = VINF_SUCCESS;
+        }
+        else
+            *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+    }
+    if (dwEventMask & EV_BREAK)
+        *pfEvtsRecv |= RTSERIALPORT_EVT_F_BREAK_DETECTED;
+    if (dwEventMask & (EV_CTS | EV_DSR | EV_RING | EV_RLSD))
+        *pfEvtsRecv |= RTSERIALPORT_EVT_F_STATUS_LINE_CHANGED;
+
+    return rc;
+}
+
+
+/**
+ * The internal comm event wait worker.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The pipe instance handle.
+ * @param   msTimeout           The timeout to wait for.
+ */
+static int rtSerialPortEvtWaitWorker(PRTSERIALPORTINTERNAL pThis, RTMSINTERVAL msTimeout)
+{
+    int rc = VINF_SUCCESS;
+    HANDLE ahWait[2];
+    ahWait[0] = pThis->hEvtDev;
+    ahWait[1] = pThis->hEvtIntr;
+
+    DWORD dwRet = WaitForMultipleObjects(2, ahWait, FALSE, msTimeout == RT_INDEFINITE_WAIT ? INFINITE : msTimeout);
+    if (dwRet == WAIT_TIMEOUT)
+        rc = VERR_TIMEOUT;
+    else if (dwRet == WAIT_FAILED)
+        rc = RTErrConvertFromWin32(GetLastError());
+    else if (dwRet == WAIT_OBJECT_0)
+        rc = VINF_SUCCESS;
+    else
+    {
+        Assert(dwRet == WAIT_OBJECT_0 + 1);
+        rc = VERR_INTERRUPTED;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortOpen(PRTSERIALPORT phSerialPort, const char *pszPortAddress, uint32_t fFlags)
+{
+    AssertPtrReturn(phSerialPort, VERR_INVALID_POINTER);
+    AssertReturn(RT_VALID_PTR(pszPortAddress) && *pszPortAddress != '\0', VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSERIALPORT_OPEN_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn((fFlags & RTSERIALPORT_OPEN_F_READ) || (fFlags & RTSERIALPORT_OPEN_F_WRITE),
+                 VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    PRTSERIALPORTINTERNAL pThis = (PRTSERIALPORTINTERNAL)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        pThis->u32Magic         = RTSERIALPORT_MAGIC;
+        pThis->fOpenFlags       = fFlags;
+        pThis->fEvtMask         = 0;
+        pThis->fWritePending    = false;
+        pThis->fEvtQueryPending = false;
+        pThis->pbBounceBuf      = NULL;
+        pThis->cbBounceBufUsed  = 0;
+        pThis->cbBounceBufAlloc = 0;
+        RT_ZERO(pThis->OverlappedEvt);
+        RT_ZERO(pThis->OverlappedWrite);
+        RT_ZERO(pThis->OverlappedRead);
+        pThis->hEvtDev          = CreateEvent(NULL, TRUE, FALSE, NULL);
+        if (pThis->hEvtDev)
+        {
+            pThis->OverlappedEvt.hEvent = pThis->hEvtDev,
+            pThis->hEvtIntr = CreateEvent(NULL, FALSE, FALSE, NULL);
+            if (pThis->hEvtIntr)
+            {
+                pThis->hEvtWrite = CreateEvent(NULL, TRUE, TRUE, NULL);
+                if (pThis->hEvtWrite)
+                {
+                    pThis->OverlappedWrite.hEvent = pThis->hEvtWrite;
+                    pThis->hEvtRead = CreateEvent(NULL, TRUE, TRUE, NULL);
+                    if (pThis->hEvtRead)
+                    {
+                        pThis->OverlappedRead.hEvent = pThis->hEvtRead;
+                        DWORD fWinFlags = 0;
+
+                        if (fFlags & RTSERIALPORT_OPEN_F_WRITE)
+                            fWinFlags |= GENERIC_WRITE;
+                        if (fFlags & RTSERIALPORT_OPEN_F_READ)
+                            fWinFlags |= GENERIC_READ;
+
+                        pThis->hDev = CreateFile(pszPortAddress,
+                                                 fWinFlags,
+                                                 0, /* Must be opened with exclusive access. */
+                                                 NULL, /* No SECURITY_ATTRIBUTES structure. */
+                                                 OPEN_EXISTING, /* Must use OPEN_EXISTING. */
+                                                 FILE_FLAG_OVERLAPPED, /* Overlapped I/O. */
+                                                 NULL);
+                        if (pThis->hDev)
+                        {
+                            rc = rtSerialPortSetDefaultCfg(pThis);
+                            if (RT_SUCCESS(rc))
+                            {
+                                *phSerialPort = pThis;
+                                return rc;
+                            }
+                        }
+                        else
+                            rc = RTErrConvertFromWin32(GetLastError());
+
+                        CloseHandle(pThis->hEvtRead);
+                    }
+
+                    CloseHandle(pThis->hEvtWrite);
+                }
+
+                CloseHandle(pThis->hEvtIntr);
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            CloseHandle(pThis->hEvtDev);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int)  RTSerialPortClose(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    if (pThis == NIL_RTSERIALPORT)
+        return VINF_SUCCESS;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    /*
+     * Do the cleanup.
+     */
+    AssertReturn(ASMAtomicCmpXchgU32(&pThis->u32Magic, RTSERIALPORT_MAGIC_DEAD, RTSERIALPORT_MAGIC), VERR_INVALID_HANDLE);
+
+    if (pThis->fWritePending)
+        rtSerialPortWriteCheckCompletion(pThis);
+
+    CloseHandle(pThis->hDev);
+    CloseHandle(pThis->hEvtDev);
+    CloseHandle(pThis->hEvtWrite);
+    CloseHandle(pThis->hEvtRead);
+    CloseHandle(pThis->hEvtIntr);
+    pThis->hDev      = NULL;
+    pThis->hEvtDev   = NULL;
+    pThis->hEvtWrite = NULL;
+    pThis->hEvtRead  = NULL;
+    pThis->hEvtIntr  = NULL;
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTHCINTPTR) RTSerialPortToNative(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, -1);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, -1);
+
+    return (RTHCINTPTR)pThis->hDev;
+}
+
+
+RTDECL(int) RTSerialPortRead(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+
+    /*
+     * Kick of an overlapped read.
+     */
+    int rc = VINF_SUCCESS;
+    uint8_t *pbBuf = (uint8_t *)pvBuf;
+
+    while (   cbToRead > 0
+           && RT_SUCCESS(rc))
+    {
+        BOOL fSucc = ResetEvent(pThis->OverlappedRead.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+        DWORD cbRead = 0;
+        if (ReadFile(pThis->hDev, pbBuf,
+                     cbToRead <= ~(DWORD)0 ? (DWORD)cbToRead : ~(DWORD)0,
+                     &cbRead, &pThis->OverlappedRead))
+        {
+            if (pcbRead)
+            {
+                *pcbRead = cbRead;
+                break;
+            }
+            rc = VINF_SUCCESS;
+        }
+        else if (GetLastError() == ERROR_IO_PENDING)
+        {
+            DWORD dwWait = WaitForSingleObject(pThis->OverlappedRead.hEvent, INFINITE);
+            if (dwWait == WAIT_OBJECT_0)
+            {
+                if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedRead, &cbRead, TRUE /*fWait*/))
+                {
+                    if (pcbRead)
+                    {
+                        *pcbRead = cbRead;
+                        break;
+                    }
+                    rc = VINF_SUCCESS;
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            else
+            {
+                Assert(dwWait == WAIT_FAILED);
+                rc = RTErrConvertFromWin32(GetLastError());
+            }
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+
+        if (RT_SUCCESS(rc))
+        {
+            cbToRead -= cbRead;
+            pbBuf    += cbRead;
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortReadNB(RTSERIALPORT hSerialPort, void *pvBuf, size_t cbToRead, size_t *pcbRead)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToRead > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbRead, VERR_INVALID_POINTER);
+
+    *pcbRead = 0;
+
+    /* Check whether there is data waiting in the input queue. */
+    int rc = VINF_SUCCESS;
+    COMSTAT ComStat; RT_ZERO(ComStat);
+    if (ClearCommError(pThis->hDev, NULL, &ComStat))
+    {
+        if (ComStat.cbInQue > 0)
+        {
+            DWORD dwToRead = RT_MIN(ComStat.cbInQue, (DWORD)cbToRead);
+            /* Kick of an overlapped read.  It should return immediately */
+            BOOL fSucc = ResetEvent(pThis->OverlappedRead.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+            DWORD cbRead = 0;
+            if (   cbToRead == 0
+                || ReadFile(pThis->hDev, pvBuf, dwToRead,
+                            &cbRead, &pThis->OverlappedRead))
+                *pcbRead = cbRead;
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                /* This shouldn't actually happen, so turn this into a synchronous read. */
+                if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedRead, &cbRead, TRUE /*fWait*/))
+                    *pcbRead = cbRead;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else
+            rc = VINF_TRY_AGAIN;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWrite(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+
+    /* If I/O is pending, check if it has completed. */
+    int rc = VINF_SUCCESS;
+    if (pThis->fWritePending)
+        rc = rtSerialPortWriteCheckCompletion(pThis);
+    if (rc == VINF_SUCCESS)
+    {
+        const uint8_t *pbBuf = (const uint8_t *)pvBuf;
+
+        while (   cbToWrite > 0
+               && RT_SUCCESS(rc))
+        {
+            BOOL fSucc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(fSucc == TRUE); RT_NOREF(fSucc);
+            DWORD cbWritten = 0;
+            if (WriteFile(pThis->hDev, pbBuf,
+                          cbToWrite <= ~(DWORD)0 ? (DWORD)cbToWrite : ~(DWORD)0,
+                          &cbWritten, &pThis->OverlappedWrite))
+            {
+                if (pcbWritten)
+                {
+                    *pcbWritten = cbWritten;
+                    break;
+                }
+                rc = VINF_SUCCESS;
+            }
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                DWORD dwWait = WaitForSingleObject(pThis->OverlappedWrite.hEvent, INFINITE);
+                if (dwWait == WAIT_OBJECT_0)
+                {
+                    if (GetOverlappedResult(pThis->hDev, &pThis->OverlappedWrite, &cbWritten, TRUE /*fWait*/))
+                    {
+                        if (pcbWritten)
+                        {
+                            *pcbWritten = cbWritten;
+                            break;
+                        }
+                        rc = VINF_SUCCESS;
+                    }
+                    else
+                        rc = RTErrConvertFromWin32(GetLastError());
+                }
+                else
+                {
+                    Assert(dwWait == WAIT_FAILED);
+                    rc = RTErrConvertFromWin32(GetLastError());
+                }
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            if (RT_SUCCESS(rc))
+            {
+                cbToWrite -= cbWritten;
+                pbBuf     += cbWritten;
+            }
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortWriteNB(RTSERIALPORT hSerialPort, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvBuf, VERR_INVALID_POINTER);
+    AssertReturn(cbToWrite > 0, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pcbWritten, VERR_INVALID_POINTER);
+
+    /* If I/O is pending, check if it has completed. */
+    int rc = VINF_SUCCESS;
+    if (pThis->fWritePending)
+        rc = rtSerialPortWriteCheckCompletion(pThis);
+    if (rc == VINF_SUCCESS)
+    {
+        Assert(!pThis->fWritePending);
+
+        /* Do the bounce buffering. */
+        if (    pThis->cbBounceBufAlloc < cbToWrite
+            &&  pThis->cbBounceBufAlloc < RTSERIALPORT_NT_SIZE)
+        {
+            if (cbToWrite > RTSERIALPORT_NT_SIZE)
+                cbToWrite = RTSERIALPORT_NT_SIZE;
+            void *pv = RTMemRealloc(pThis->pbBounceBuf, RT_ALIGN_Z(cbToWrite, _1K));
+            if (pv)
+            {
+                pThis->pbBounceBuf = (uint8_t *)pv;
+                pThis->cbBounceBufAlloc = RT_ALIGN_Z(cbToWrite, _1K);
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+        else if (cbToWrite > RTSERIALPORT_NT_SIZE)
+            cbToWrite = RTSERIALPORT_NT_SIZE;
+        if (RT_SUCCESS(rc) && cbToWrite)
+        {
+            memcpy(pThis->pbBounceBuf, pvBuf, cbToWrite);
+            pThis->cbBounceBufUsed = (uint32_t)cbToWrite;
+
+            /* Submit the write. */
+            rc = ResetEvent(pThis->OverlappedWrite.hEvent); Assert(rc == TRUE);
+            DWORD cbWritten = 0;
+            if (WriteFile(pThis->hDev, pThis->pbBounceBuf, (DWORD)pThis->cbBounceBufUsed,
+                          &cbWritten, &pThis->OverlappedWrite))
+            {
+                *pcbWritten = RT_MIN(cbWritten, cbToWrite); /* paranoia^3 */
+                rc = VINF_SUCCESS;
+            }
+            else if (GetLastError() == ERROR_IO_PENDING)
+            {
+                *pcbWritten = cbToWrite;
+                pThis->fWritePending = true;
+                rc = VINF_SUCCESS;
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+        }
+        else if (RT_SUCCESS(rc))
+            *pcbWritten = 0;
+    }
+    else if (RT_SUCCESS(rc))
+        *pcbWritten = 0;
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortCfgQueryCurrent(RTSERIALPORT hSerialPort, PRTSERIALPORTCFG pCfg)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    pCfg->uBaudRate = pThis->PortCfg.BaudRate;
+    switch (pThis->PortCfg.Parity)
+    {
+        case NOPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_NONE;
+            break;
+        case EVENPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_EVEN;
+            break;
+        case ODDPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_ODD;
+            break;
+        case MARKPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_MARK;
+            break;
+        case SPACEPARITY:
+            pCfg->enmParity = RTSERIALPORTPARITY_SPACE;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    switch (pThis->PortCfg.ByteSize)
+    {
+        case 5:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_5BITS;
+            break;
+        case 6:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_6BITS;
+            break;
+        case 7:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_7BITS;
+            break;
+        case 8:
+            pCfg->enmDataBitCount = RTSERIALPORTDATABITS_8BITS;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    switch (pThis->PortCfg.StopBits)
+    {
+        case ONESTOPBIT:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_ONE;
+            break;
+        case ONE5STOPBITS:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_ONEPOINTFIVE;
+            break;
+        case TWOSTOPBITS:
+            pCfg->enmStopBitCount = RTSERIALPORTSTOPBITS_TWO;
+            break;
+        default:
+            AssertFailed();
+            return VERR_INTERNAL_ERROR;
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSerialPortCfgSet(RTSERIALPORT hSerialPort, PCRTSERIALPORTCFG pCfg, PRTERRINFO pErrInfo)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    RT_NOREF(pErrInfo);
+
+    DCB DcbNew;
+    memcpy(&DcbNew, &pThis->PortCfg, sizeof(DcbNew));
+    DcbNew.BaudRate = pCfg->uBaudRate;
+
+    switch (pCfg->enmParity)
+    {
+        case RTSERIALPORTPARITY_NONE:
+            DcbNew.Parity = NOPARITY;
+            break;
+        case RTSERIALPORTPARITY_EVEN:
+            DcbNew.Parity = EVENPARITY;
+            break;
+        case RTSERIALPORTPARITY_ODD:
+            DcbNew.Parity = ODDPARITY;
+            break;
+        case RTSERIALPORTPARITY_MARK:
+            DcbNew.Parity = MARKPARITY;
+            break;
+        case RTSERIALPORTPARITY_SPACE:
+            DcbNew.Parity = SPACEPARITY;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    switch (pCfg->enmDataBitCount)
+    {
+        case RTSERIALPORTDATABITS_5BITS:
+            DcbNew.ByteSize = 5;
+            break;
+        case RTSERIALPORTDATABITS_6BITS:
+            DcbNew.ByteSize = 6;
+            break;
+        case RTSERIALPORTDATABITS_7BITS:
+            DcbNew.ByteSize = 7;
+            break;
+        case RTSERIALPORTDATABITS_8BITS:
+            DcbNew.ByteSize = 8;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    switch (pCfg->enmStopBitCount)
+    {
+        case RTSERIALPORTSTOPBITS_ONE:
+            DcbNew.StopBits = ONESTOPBIT;
+            break;
+        case RTSERIALPORTSTOPBITS_ONEPOINTFIVE:
+            AssertReturn(pCfg->enmDataBitCount == RTSERIALPORTDATABITS_5BITS, VERR_INVALID_PARAMETER);
+            DcbNew.StopBits = ONE5STOPBITS;
+            break;
+        case RTSERIALPORTSTOPBITS_TWO:
+            AssertReturn(pCfg->enmDataBitCount != RTSERIALPORTDATABITS_5BITS, VERR_INVALID_PARAMETER);
+            DcbNew.StopBits = TWOSTOPBITS;
+            break;
+        default:
+            AssertFailedReturn(VERR_INVALID_PARAMETER);
+    }
+
+    int rc = VINF_SUCCESS;
+    if (!SetCommState(pThis->hDev, &DcbNew))
+        rc = RTErrConvertFromWin32(GetLastError());
+    else
+        memcpy(&pThis->PortCfg, &DcbNew, sizeof(DcbNew));
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPoll(RTSERIALPORT hSerialPort, uint32_t fEvtMask, uint32_t *pfEvtsRecv,
+                                RTMSINTERVAL msTimeout)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!(fEvtMask & ~RTSERIALPORT_EVT_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pfEvtsRecv, VERR_INVALID_POINTER);
+
+    *pfEvtsRecv = 0;
+
+    int rc = VINF_SUCCESS;
+    if (fEvtMask != pThis->fEvtMask)
+    {
+        rc = rtSerialPortWinUpdateEvtMask(pThis, fEvtMask);
+        if (   RT_SUCCESS(rc)
+            && pThis->fEvtQueryPending)
+        {
+            /*
+             * Setting a new event mask lets the WaitCommEvent() call finish immediately,
+             * so clean up and process any events here.
+             */
+            rc = rtSerialPortEvtWaitWorker(pThis, 1);
+            AssertRC(rc);
+
+            if (pThis->dwEventMask != 0)
+            {
+                pThis->fEvtQueryPending = false;
+                return rtSerialPortEvtFlagsProcess(pThis, pThis->dwEventMask, pfEvtsRecv);
+            }
+        }
+    }
+
+    /*
+     * EV_RXCHAR is triggered only if a byte is received after the event mask is set,
+     * not if there is already something in the input buffer. Thatswhy we check the input
+     * buffer for any stored data and the output buffer whether it is empty and return
+     * the appropriate flags.
+     */
+    if (RT_SUCCESS(rc))
+    {
+        COMSTAT ComStat; RT_ZERO(ComStat);
+        if (!ClearCommError(pThis->hDev, NULL, &ComStat))
+            return RTErrConvertFromWin32(GetLastError());
+
+        /* Check whether data is already waiting in the input buffer. */
+        if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_RX)
+            && ComStat.cbInQue > 0)
+            *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_RX;
+
+        /* Check whether the output buffer is empty. */
+        if (   (fEvtMask & RTSERIALPORT_EVT_F_DATA_TX)
+            && ComStat.cbOutQue == 0)
+            *pfEvtsRecv |= RTSERIALPORT_EVT_F_DATA_TX;
+
+        /* Return if there is at least one event. */
+        if (*pfEvtsRecv != 0)
+            return VINF_SUCCESS;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        /* Set up a new event wait if there is none pending. */
+        if (!pThis->fEvtQueryPending)
+        {
+            RT_ZERO(pThis->OverlappedEvt);
+            pThis->OverlappedEvt.hEvent = pThis->hEvtDev;
+
+            pThis->dwEventMask = 0;
+            pThis->fEvtQueryPending = true;
+            if (!WaitCommEvent(pThis->hDev, &pThis->dwEventMask, &pThis->OverlappedEvt))
+            {
+                DWORD dwRet = GetLastError();
+                if (dwRet == ERROR_IO_PENDING)
+                    rc = VINF_SUCCESS;
+                else
+                {
+                    rc = RTErrConvertFromWin32(GetLastError());
+                    pThis->fEvtQueryPending = false;
+                }
+            }
+            else
+                pThis->fEvtQueryPending = false;
+        }
+
+        if (   RT_SUCCESS(rc)
+            && pThis->fEvtQueryPending)
+            rc = rtSerialPortEvtWaitWorker(pThis, msTimeout);
+
+        if (RT_SUCCESS(rc))
+        {
+            pThis->fEvtQueryPending = false;
+            rc = rtSerialPortEvtFlagsProcess(pThis, pThis->dwEventMask, pfEvtsRecv);
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortEvtPollInterrupt(RTSERIALPORT hSerialPort)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    if (!SetEvent(pThis->hEvtIntr))
+        return RTErrConvertFromWin32(GetLastError());
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTSerialPortChgBreakCondition(RTSERIALPORT hSerialPort, bool fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    BOOL fSucc = FALSE;
+    if (fSet)
+        fSucc = SetCommBreak(pThis->hDev);
+    else
+        fSucc = ClearCommBreak(pThis->hDev);
+
+    int rc = VINF_SUCCESS;
+    if (!fSucc)
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortChgStatusLines(RTSERIALPORT hSerialPort, uint32_t fClear, uint32_t fSet)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+
+    BOOL fSucc = TRUE;
+    if (fSet & RTSERIALPORT_CHG_STS_LINES_F_DTR)
+        fSucc = EscapeCommFunction(pThis->hDev, SETDTR);
+    if (   fSucc
+        && (fSet & RTSERIALPORT_CHG_STS_LINES_F_RTS))
+        fSucc = EscapeCommFunction(pThis->hDev, SETRTS);
+
+    if (   fSucc
+        && (fClear & RTSERIALPORT_CHG_STS_LINES_F_DTR))
+        fSucc = EscapeCommFunction(pThis->hDev, CLRDTR);
+    if (   fSucc
+        && (fClear & RTSERIALPORT_CHG_STS_LINES_F_RTS))
+        fSucc = EscapeCommFunction(pThis->hDev, CLRRTS);
+
+    int rc = VINF_SUCCESS;
+    if (!fSucc)
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTSerialPortQueryStatusLines(RTSERIALPORT hSerialPort, uint32_t *pfStsLines)
+{
+    PRTSERIALPORTINTERNAL pThis = hSerialPort;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSERIALPORT_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pfStsLines, VERR_INVALID_POINTER);
+
+    *pfStsLines = 0;
+
+    int rc = VINF_SUCCESS;
+    DWORD fStsLinesQueried = 0;
+
+    /* Get the new state */
+    if (GetCommModemStatus(pThis->hDev, &fStsLinesQueried))
+    {
+        *pfStsLines |= (fStsLinesQueried & MS_RLSD_ON) ? RTSERIALPORT_STS_LINE_DCD : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_RING_ON) ? RTSERIALPORT_STS_LINE_RI  : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_DSR_ON) ? RTSERIALPORT_STS_LINE_DSR : 0;
+        *pfStsLines |= (fStsLinesQueried & MS_CTS_ON) ? RTSERIALPORT_STS_LINE_CTS : 0;
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/shmem-win.cpp b/src/VBox/Runtime/r3/win/shmem-win.cpp
new file mode 100644
index 00000000..b97fc796
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/shmem-win.cpp
@@ -0,0 +1,473 @@
+/* $Id: shmem-win.cpp $ */
+/** @file
+ * IPRT - Named shared memory object, Windows Implementation.
+ */
+
+/*
+ * Copyright (C) 2018-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/shmem.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/cdefs.h>
+#include <iprt/err.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+#include "internal/magics.h"
+#include "internal/path.h"
+#include "internal-r3-win.h" /* For g_enmWinVer + kRTWinOSType_XXX */
+
+/*
+ * Define values ourselves in case the compiling host is too old.
+ * See https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-createfilemappinga
+ * for when these were introduced.
+ */
+#ifndef PAGE_EXECUTE_READ
+# define PAGE_EXECUTE_READ 0x20
+#endif
+#ifndef PAGE_EXECUTE_READWRITE
+# define PAGE_EXECUTE_READWRITE 0x40
+#endif
+#ifndef PAGE_EXECUTE_WRITECOPY
+# define PAGE_EXECUTE_WRITECOPY 0x80
+#endif
+#ifndef FILE_MAP_EXECUTE
+# define FILE_MAP_EXECUTE 0x20
+#endif
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Shared memory object mapping descriptor.
+ */
+typedef struct RTSHMEMMAPPINGDESC
+{
+    /** Number of references held to this mapping, 0 if the descriptor is free. */
+    volatile uint32_t   cMappings;
+    /** Pointer to the region mapping. */
+    void               *pvMapping;
+    /** Start offset */
+    size_t              offRegion;
+    /** Size of the region. */
+    size_t              cbRegion;
+    /** Access flags for this region .*/
+    uint32_t            fFlags;
+} RTSHMEMMAPPINGDESC;
+/** Pointer to a shared memory object mapping descriptor. */
+typedef RTSHMEMMAPPINGDESC *PRTSHMEMMAPPINGDESC;
+/** Pointer to a constant shared memory object mapping descriptor. */
+typedef const RTSHMEMMAPPINGDESC *PCRTSHMEMMAPPINGDESC;
+
+
+/**
+ * Internal shared memory object state.
+ */
+typedef struct RTSHMEMINT
+{
+    /** Magic value (RTSHMEM_MAGIC). */
+    uint32_t            u32Magic;
+    /** Flag whether this instance created the named shared memory object. */
+    bool                fCreate;
+    /** Handle to the underlying mapping object. */
+    HANDLE              hShmObj;
+    /** Size of the mapping object in bytes. */
+    size_t              cbMax;
+    /** Overall number of mappings active for this shared memory object. */
+    volatile uint32_t   cMappings;
+    /** Maximum number of mapping descriptors allocated. */
+    uint32_t            cMappingDescsMax;
+    /** Number of mapping descriptors used. */
+    volatile uint32_t   cMappingDescsUsed;
+    /** Array of mapping descriptors - variable in size. */
+    RTSHMEMMAPPINGDESC  aMappingDescs[1];
+} RTSHMEMINT;
+/** Pointer to the internal shared memory object state. */
+typedef RTSHMEMINT *PRTSHMEMINT;
+
+
+
+
+/**
+ * Returns a mapping descriptor matching the given region properties or NULL if none was found.
+ *
+ * @returns Pointer to the matching mapping descriptor or NULL if not found.
+ * @param   pThis           Pointer to the shared memory object instance.
+ * @param   offRegion       Offset into the shared memory object to start mapping at.
+ * @param   cbRegion        Size of the region to map.
+ * @param   fFlags          Desired properties of the mapped region, combination of RTSHMEM_MAP_F_* defines.
+ */
+DECLINLINE(PRTSHMEMMAPPINGDESC) rtShMemMappingDescFindByProp(PRTSHMEMINT pThis, size_t offRegion, size_t cbRegion, uint32_t fFlags)
+{
+    for (uint32_t i = 0; i < pThis->cMappingDescsMax; i++)
+    {
+        if (   pThis->aMappingDescs[i].offRegion == offRegion
+            && pThis->aMappingDescs[i].cbRegion == cbRegion
+            && pThis->aMappingDescs[i].fFlags == fFlags)
+            return &pThis->aMappingDescs[i];
+    }
+
+    return NULL;
+}
+
+
+RTDECL(int) RTShMemOpen(PRTSHMEM phShMem, const char *pszName, uint32_t fFlags, size_t cbMax, uint32_t cMappingsHint)
+{
+    AssertPtrReturn(phShMem, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszName, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSHMEM_O_F_VALID_MASK), VERR_INVALID_PARAMETER);
+    AssertReturn(cMappingsHint < 64, VERR_OUT_OF_RANGE);
+    AssertReturn(cbMax > 0 || !(fFlags & RTSHMEM_O_F_CREATE), VERR_NOT_SUPPORTED);
+
+    if (fFlags & RTSHMEM_O_F_TRUNCATE)
+        return VERR_NOT_SUPPORTED;
+
+    /*
+     * The executable access was introduced with Windows XP SP2 and Windows Server 2003 SP1,
+     * PAGE_EXECUTE_WRITECOPY was not available until Windows Vista SP1.
+     * Allow execute mappings only starting from Windows 7 to keep the checks simple here (lazy coder).
+     */
+    if (   (fFlags & RTSHMEM_O_F_MAYBE_EXEC)
+        && g_enmWinVer < kRTWinOSType_7)
+        return VERR_NOT_SUPPORTED;
+
+    cMappingsHint = cMappingsHint == 0 ? 5 : cMappingsHint;
+    int rc = VINF_SUCCESS;
+    PRTSHMEMINT pThis = (PRTSHMEMINT)RTMemAllocZ(RT_UOFFSETOF_DYN(RTSHMEMINT, aMappingDescs[cMappingsHint]));
+    if (RT_LIKELY(pThis))
+    {
+        pThis->u32Magic            = RTSHMEM_MAGIC;
+        /*pThis->fCreate           = false; */
+        /*pThis->cMappings         = 0; */
+        pThis->cMappingDescsMax    = cMappingsHint;
+        /*pThis->cMappingDescsUsed = 0; */
+        /* Construct the filename, always use the local namespace, global requires special privileges. */
+        char szName[RTPATH_MAX];
+        ssize_t cch = RTStrPrintf2(&szName[0], sizeof(szName), "Local\\%s", pszName);
+        if (cch > 0)
+        {
+            PRTUTF16 pwszName = NULL;
+            rc = RTStrToUtf16Ex(&szName[0], RTSTR_MAX, &pwszName, 0, NULL);
+            if (RT_SUCCESS(rc))
+            {
+                if (fFlags & RTSHMEM_O_F_CREATE)
+                {
+#if HC_ARCH_BITS == 64
+                    DWORD dwSzMaxHigh = cbMax >> 32;
+#elif HC_ARCH_BITS == 32
+                    DWORD dwSzMaxHigh = 0;
+#else
+# error "Port me"
+#endif
+                    DWORD dwSzMaxLow = cbMax & UINT32_C(0xffffffff);
+                    DWORD fProt = 0;
+
+                    if (fFlags & RTSHMEM_O_F_MAYBE_EXEC)
+                    {
+                        if ((fFlags & RTSHMEM_O_F_READWRITE) == RTSHMEM_O_F_READ)
+                            fProt |= PAGE_EXECUTE_READ;
+                        else
+                            fProt |= PAGE_EXECUTE_READWRITE;
+                    }
+                    else
+                    {
+                        if ((fFlags & RTSHMEM_O_F_READWRITE) == RTSHMEM_O_F_READ)
+                            fProt |= PAGE_READONLY;
+                        else
+                            fProt |= PAGE_READWRITE;
+                    }
+                    pThis->hShmObj = CreateFileMappingW(INVALID_HANDLE_VALUE, NULL, fProt,
+                                                        dwSzMaxHigh, dwSzMaxLow, pwszName);
+                }
+                else
+                {
+                    DWORD fProt = SECTION_QUERY;
+                    if (fFlags & RTSHMEM_O_F_MAYBE_EXEC)
+                        fProt |= FILE_MAP_EXECUTE;
+                    if (fFlags & RTSHMEM_O_F_READ)
+                        fProt |= FILE_MAP_READ;
+                    if (fFlags & RTSHMEM_O_F_WRITE)
+                        fProt |= FILE_MAP_WRITE;
+
+                    pThis->hShmObj = OpenFileMappingW(fProt, FALSE, pwszName);
+                }
+                RTUtf16Free(pwszName);
+                if (pThis->hShmObj != NULL)
+                {
+                    *phShMem = pThis;
+                    return VINF_SUCCESS;
+                }
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+        }
+        else
+            rc = VERR_BUFFER_OVERFLOW;
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemClose(RTSHMEM hShMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->cMappings, VERR_INVALID_STATE);
+
+    int rc = VINF_SUCCESS;
+    if (CloseHandle(pThis->hShmObj))
+    {
+        pThis->u32Magic = RTSHMEM_MAGIC_DEAD;
+        RTMemFree(pThis);
+    }
+    else
+        rc = RTErrConvertFromWin32(GetLastError());
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemDelete(const char *pszName)
+{
+    AssertPtrReturn(pszName, VERR_INVALID_POINTER);
+    AssertReturn(*pszName != '\0', VERR_INVALID_PARAMETER);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(uint32_t) RTShMemRefCount(RTSHMEM hShMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, 0);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, 0);
+
+    return pThis->cMappings;
+}
+
+
+RTDECL(int) RTShMemSetSize(RTSHMEM hShMem, size_t cbMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertReturn(!pThis->cMappings, VERR_INVALID_STATE);
+    AssertReturn(cbMem, VERR_NOT_SUPPORTED);
+
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTDECL(int) RTShMemQuerySize(RTSHMEM hShMem, size_t *pcbMem)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pcbMem, VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    SECTION_BASIC_INFORMATION SecInf;
+    SIZE_T cbRet;
+    NTSTATUS rcNt = NtQuerySection(pThis->hShmObj, SectionBasicInformation, &SecInf, sizeof(SecInf), &cbRet);
+    if (NT_SUCCESS(rcNt))
+    {
+        AssertReturn(cbRet == sizeof(SecInf), VERR_INTERNAL_ERROR);
+#if HC_ARCH_BITS == 32
+        AssertReturn(SecInf.MaximumSize.HighPart == 0, VERR_INTERNAL_ERROR_2);
+        *pcbMem = SecInf.MaximumSize.LowPart;
+#elif HC_ARCH_BITS == 64
+        *pcbMem = SecInf.MaximumSize.QuadPart;
+#else
+# error "Port me"
+#endif
+    }
+    else
+        rc = RTErrConvertFromNtStatus(rcNt);
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemMapRegion(RTSHMEM hShMem, size_t offRegion, size_t cbRegion, uint32_t fFlags, void **ppv)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(ppv, VERR_INVALID_PARAMETER);
+    AssertReturn(!(fFlags & ~RTSHMEM_MAP_F_VALID_MASK), VERR_INVALID_PARAMETER);
+
+    /* See comment in RTShMemOpen(). */
+    if (   (fFlags & RTSHMEM_MAP_F_EXEC)
+        && g_enmWinVer < kRTWinOSType_7)
+        return VERR_NOT_SUPPORTED;
+
+    /* Try to find a mapping with compatible parameters first. */
+    PRTSHMEMMAPPINGDESC pMappingDesc = NULL;
+    for (uint32_t iTry = 0; iTry < 10; iTry++)
+    {
+        pMappingDesc = rtShMemMappingDescFindByProp(pThis, offRegion, cbRegion, fFlags);
+        if (!pMappingDesc)
+            break;
+
+        /* Increase the mapping count and check that the region is still accessible by us. */
+        if (   ASMAtomicIncU32(&pMappingDesc->cMappings) > 1
+            && pMappingDesc->offRegion == offRegion
+            && pMappingDesc->cbRegion  == cbRegion
+            && pMappingDesc->fFlags    == fFlags)
+            break;
+        /* Mapping was freed inbetween, next round. */
+    }
+
+    int rc = VINF_SUCCESS;
+    if (!pMappingDesc)
+    {
+        /* Find an empty region descriptor and map the region. */
+        for (uint32_t i = 0; i < pThis->cMappingDescsMax && !pMappingDesc; i++)
+        {
+            if (!pThis->aMappingDescs[i].cMappings)
+            {
+                pMappingDesc = &pThis->aMappingDescs[i];
+
+                /* Try to grab this one. */
+                if (ASMAtomicIncU32(&pMappingDesc->cMappings) == 1)
+                    break;
+
+                /* Somebody raced us, drop reference and continue. */
+                ASMAtomicDecU32(&pMappingDesc->cMappings);
+                pMappingDesc = NULL;
+            }
+        }
+
+        if (RT_LIKELY(pMappingDesc))
+        {
+            /* Try to map it. */
+            DWORD fProt = 0;
+            DWORD offLow = offRegion & UINT32_C(0xffffffff);
+#if HC_ARCH_BITS == 64
+            DWORD offHigh = offRegion >> 32;
+#elif HC_ARCH_BITS == 32
+            DWORD offHigh = 0;
+#else
+# error "Port me"
+#endif
+            if (fFlags & RTSHMEM_MAP_F_READ)
+                fProt |= FILE_MAP_READ;
+            if (fFlags & RTSHMEM_MAP_F_WRITE)
+                fProt |= FILE_MAP_WRITE;
+            if (fFlags & RTSHMEM_MAP_F_EXEC)
+                fProt |= FILE_MAP_EXECUTE;
+            if (fFlags & RTSHMEM_MAP_F_COW)
+                fProt |= FILE_MAP_COPY;
+
+            void *pv = MapViewOfFile(pThis->hShmObj, fProt, offHigh, offLow, cbRegion);
+            if (pv != NULL)
+            {
+                pMappingDesc->pvMapping = pv;
+                pMappingDesc->offRegion = offRegion;
+                pMappingDesc->cbRegion  = cbRegion;
+                pMappingDesc->fFlags    = fFlags;
+            }
+            else
+            {
+                rc = RTErrConvertFromWin32(GetLastError());
+                ASMAtomicDecU32(&pMappingDesc->cMappings);
+            }
+        }
+        else
+            rc = VERR_SHMEM_MAXIMUM_MAPPINGS_REACHED;
+    }
+
+    if (RT_SUCCESS(rc))
+    {
+        *ppv = pMappingDesc->pvMapping;
+        ASMAtomicIncU32(&pThis->cMappings);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTShMemUnmapRegion(RTSHMEM hShMem, void *pv)
+{
+    PRTSHMEMINT pThis = hShMem;
+    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
+    AssertReturn(pThis->u32Magic == RTSHMEM_MAGIC, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pv, VERR_INVALID_PARAMETER);
+
+    /* Find the mapping descriptor by the given region address. */
+    PRTSHMEMMAPPINGDESC pMappingDesc = NULL;
+    for (uint32_t i = 0; i < pThis->cMappingDescsMax && !pMappingDesc; i++)
+    {
+        if (pThis->aMappingDescs[i].pvMapping == pv)
+        {
+            pMappingDesc = &pThis->aMappingDescs[i];
+            break;
+        }
+    }
+
+    AssertPtrReturn(pMappingDesc, VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    if (!ASMAtomicDecU32(&pMappingDesc->cMappings))
+    {
+        /* Last mapping of this region was unmapped, so do the real unmapping now. */
+        if (UnmapViewOfFile(pv))
+        {
+            ASMAtomicDecU32(&pThis->cMappingDescsUsed);
+            ASMAtomicDecU32(&pThis->cMappings);
+        }
+        else
+        {
+            ASMAtomicIncU32(&pMappingDesc->cMappings);
+            rc = RTErrConvertFromWin32(GetLastError());
+        }
+    }
+
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/symlink-win.cpp b/src/VBox/Runtime/r3/win/symlink-win.cpp
new file mode 100644
index 00000000..a0c5f1e2
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/symlink-win.cpp
@@ -0,0 +1,367 @@
+/* $Id: symlink-win.cpp $ */
+/** @file
+ * IPRT - Symbolic Links, Windows.
+ */
+
+/*
+ * Copyright (C) 2010-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_SYMLINK
+#include <iprt/win/windows.h>
+
+#include <iprt/symlink.h>
+#include "internal-r3-win.h"
+
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/path.h>
+#include <iprt/mem.h>
+#include <iprt/string.h>
+#include <iprt/utf16.h>
+#include "internal/path.h"
+
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct MY_REPARSE_DATA_BUFFER
+{
+    ULONG           ReparseTag;
+#define MY_IO_REPARSE_TAG_SYMLINK       0xa000000c
+#define MY_IO_REPARSE_TAG_MOUNT_POINT   0xa0000003
+
+    USHORT          ReparseDataLength;
+    USHORT          Reserved;
+    union
+    {
+        struct
+        {
+            USHORT  SubstituteNameOffset;
+            USHORT  SubstituteNameLength;
+            USHORT  PrintNameOffset;
+            USHORT  PrintNameLength;
+            ULONG   Flags;
+#define MY_SYMLINK_FLAG_RELATIVE 1
+            WCHAR   PathBuffer[1];
+        } SymbolicLinkReparseBuffer;
+        struct
+        {
+            USHORT  SubstituteNameOffset;
+            USHORT  SubstituteNameLength;
+            USHORT  PrintNameOffset;
+            USHORT  PrintNameLength;
+            WCHAR   PathBuffer[1];
+        } MountPointReparseBuffer;
+        struct
+        {
+            UCHAR   DataBuffer[1];
+        } GenericReparseBuffer;
+    };
+} MY_REPARSE_DATA_BUFFER;
+#define MY_FSCTL_GET_REPARSE_POINT CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 42, METHOD_BUFFERED, FILE_ANY_ACCESS)
+
+
+RTDECL(bool) RTSymlinkExists(const char *pszSymlink)
+{
+    bool        fRc = false;
+    RTFSOBJINFO ObjInfo;
+    int rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
+    if (RT_SUCCESS(rc))
+        fRc = RTFS_IS_SYMLINK(ObjInfo.Attr.fMode);
+
+    LogFlow(("RTSymlinkExists(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
+    return fRc;
+}
+
+
+RTDECL(bool) RTSymlinkIsDangling(const char *pszSymlink)
+{
+    bool        fRc = false;
+    RTFSOBJINFO ObjInfo;
+    int rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_ON_LINK);
+    if (RT_SUCCESS(rc))
+    {
+        fRc = RTFS_IS_SYMLINK(ObjInfo.Attr.fMode);
+        if (fRc)
+        {
+            rc = RTPathQueryInfoEx(pszSymlink, &ObjInfo, RTFSOBJATTRADD_NOTHING, RTPATH_F_FOLLOW_LINK);
+            fRc = !RT_SUCCESS_NP(rc);
+        }
+    }
+
+    LogFlow(("RTSymlinkIsDangling(%p={%s}): returns %RTbool\n", pszSymlink, pszSymlink, fRc));
+    return fRc;
+}
+
+
+RTDECL(int) RTSymlinkCreate(const char *pszSymlink, const char *pszTarget, RTSYMLINKTYPE enmType, uint32_t fCreate)
+{
+    /*
+     * Validate the input.
+     */
+    AssertReturn(enmType > RTSYMLINKTYPE_INVALID && enmType < RTSYMLINKTYPE_END, VERR_INVALID_PARAMETER);
+    AssertPtrReturn(pszSymlink, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszTarget, VERR_INVALID_POINTER);
+    RT_NOREF_PV(fCreate);
+
+    /*
+     * Resolve the API.
+     */
+    typedef BOOLEAN (WINAPI *PFNCREATESYMBOLICLINKW)(LPCWSTR, LPCWSTR, DWORD);
+    static PFNCREATESYMBOLICLINKW   s_pfnCreateSymbolicLinkW = NULL;
+    static bool                     s_fTried = FALSE;
+    if (!s_fTried)
+    {
+        PFNCREATESYMBOLICLINKW pfn = (PFNCREATESYMBOLICLINKW)GetProcAddress(g_hModKernel32, "CreateSymbolicLinkW");
+        if (pfn)
+            s_pfnCreateSymbolicLinkW = pfn;
+        s_fTried = true;
+    }
+    if (!s_pfnCreateSymbolicLinkW)
+    {
+        LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d, %#x): returns VERR_NOT_SUPPORTED - Windows API not found\n",
+                 pszSymlink, pszSymlink, pszTarget, pszTarget, enmType, fCreate));
+        return VERR_NOT_SUPPORTED;
+    }
+
+    /*
+     * Convert the paths.
+     */
+    PRTUTF16 pwszNativeSymlink;
+    int rc = RTPathWinFromUtf8(&pwszNativeSymlink, pszSymlink, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        PRTUTF16 pwszNativeTarget;
+        rc = RTPathWinFromUtf8(&pwszNativeTarget, pszTarget, 0 /*fFlags*/);
+        if (RT_SUCCESS(rc))
+        {
+            /* The link target path must use backslashes to work reliably. */
+            RTUTF16  wc;
+            PRTUTF16 pwsz = pwszNativeTarget;
+            while ((wc = *pwsz) != '\0')
+            {
+                if (wc == '/')
+                    *pwsz = '\\';
+                pwsz++;
+            }
+
+            /*
+             * Massage the target path, determin the link type.
+             */
+            size_t cchTarget        = strlen(pszTarget);
+            size_t cchVolSpecTarget = rtPathVolumeSpecLen(pszTarget);
+#if 0 /* looks like this isn't needed after all. That makes everything much simper :-) */
+            if (   cchTarget > RT_MIN(cchVolSpecTarget, 1)
+                && RTPATH_IS_SLASH(pszTarget[cchTarget - 1]))
+            {
+                size_t cwcNativeTarget = RTUtf16Len(pwszNativeTarget);
+                size_t offFromEnd = 1;
+                while (   offFromEnd < cchTarget
+                       && cchTarget - offFromEnd >= cchVolSpecTarget
+                       && RTPATH_IS_SLASH(pszTarget[cchTarget - offFromEnd]))
+                {
+                    Assert(offFromEnd < cwcNativeTarget);
+                    pwszNativeTarget[cwcNativeTarget - offFromEnd] = 0;
+                    offFromEnd++;
+                }
+            }
+#endif
+
+            if (enmType == RTSYMLINKTYPE_UNKNOWN)
+            {
+                if (   cchTarget > cchVolSpecTarget
+                    && RTPATH_IS_SLASH(pszTarget[cchTarget - 1]))
+                    enmType = RTSYMLINKTYPE_DIR;
+                else if (cchVolSpecTarget)
+                {
+                    /** @todo this is subject to sharing violations. */
+                    DWORD dwAttr = GetFileAttributesW(pwszNativeTarget);
+                    if (   dwAttr != INVALID_FILE_ATTRIBUTES
+                        && (dwAttr & FILE_ATTRIBUTE_DIRECTORY))
+                        enmType = RTSYMLINKTYPE_DIR;
+                }
+                else
+                {
+                    /** @todo Join the symlink directory with the target and
+                     *        look up the attributes on that. -lazy bird. */
+                }
+            }
+
+            /*
+             * Create the link.
+             */
+            if (s_pfnCreateSymbolicLinkW(pwszNativeSymlink, pwszNativeTarget, enmType == RTSYMLINKTYPE_DIR))
+                rc = VINF_SUCCESS;
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+
+            RTPathWinFree(pwszNativeTarget);
+        }
+        RTPathWinFree(pwszNativeSymlink);
+    }
+
+    LogFlow(("RTSymlinkCreate(%p={%s}, %p={%s}, %d, %#x): returns %Rrc\n", pszSymlink, pszSymlink, pszTarget, pszTarget, enmType, fCreate, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkDelete(const char *pszSymlink, uint32_t fDelete)
+{
+    RT_NOREF_PV(fDelete);
+
+    /*
+     * Convert the path.
+     */
+    PRTUTF16 pwszNativeSymlink;
+    int rc = RTPathWinFromUtf8(&pwszNativeSymlink, pszSymlink, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * We have to use different APIs depending on whether this is a
+         * directory or file link.  This means we're subject to one more race
+         * than on posix at the moment.  We could probably avoid this though,
+         * if we wanted to go talk with the native API layer below Win32...
+         */
+        DWORD dwAttr = GetFileAttributesW(pwszNativeSymlink);
+        if (dwAttr != INVALID_FILE_ATTRIBUTES)
+        {
+            if (dwAttr & FILE_ATTRIBUTE_REPARSE_POINT)
+            {
+                BOOL fRc;
+                if (dwAttr & FILE_ATTRIBUTE_DIRECTORY)
+                    fRc = RemoveDirectoryW(pwszNativeSymlink);
+                else
+                    fRc = DeleteFileW(pwszNativeSymlink);
+                if (fRc)
+                    rc = VINF_SUCCESS;
+                else
+                    rc = RTErrConvertFromWin32(GetLastError());
+            }
+            else
+                rc = VERR_NOT_SYMLINK;
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        RTPathWinFree(pwszNativeSymlink);
+    }
+
+    LogFlow(("RTSymlinkDelete(%p={%s}, %#x): returns %Rrc\n", pszSymlink, pszSymlink, fDelete, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkRead(const char *pszSymlink, char *pszTarget, size_t cbTarget, uint32_t fRead)
+{
+    RT_NOREF_PV(fRead);
+
+    char *pszMyTarget;
+    int rc = RTSymlinkReadA(pszSymlink, &pszMyTarget);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTStrCopy(pszTarget, cbTarget, pszMyTarget);
+        RTStrFree(pszMyTarget);
+    }
+    LogFlow(("RTSymlinkRead(%p={%s}): returns %Rrc\n", pszSymlink, pszSymlink, rc));
+    return rc;
+}
+
+
+RTDECL(int) RTSymlinkReadA(const char *pszSymlink, char **ppszTarget)
+{
+    AssertPtr(ppszTarget);
+    PRTUTF16 pwszNativeSymlink;
+    int rc = RTPathWinFromUtf8(&pwszNativeSymlink, pszSymlink, 0 /*fFlags*/);
+    if (RT_SUCCESS(rc))
+    {
+        HANDLE hSymlink = CreateFileW(pwszNativeSymlink,
+                                      GENERIC_READ,
+                                      FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                                      NULL,
+                                      OPEN_EXISTING,
+                                      FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS,
+                                      NULL);
+        if (hSymlink != INVALID_HANDLE_VALUE)
+        {
+            DWORD cbReturned = 0;
+            union
+            {
+                MY_REPARSE_DATA_BUFFER  Buf;
+                uint8_t                 abBuf[16*_1K + sizeof(WCHAR)];
+            } u;
+            if (DeviceIoControl(hSymlink,
+                                MY_FSCTL_GET_REPARSE_POINT,
+                                NULL /*pInBuffer */,
+                                0 /*cbInBuffer */,
+                                &u.Buf,
+                                sizeof(u) - sizeof(WCHAR),
+                                &cbReturned,
+                                NULL /*pOverlapped*/))
+            {
+                if (u.Buf.ReparseTag == MY_IO_REPARSE_TAG_SYMLINK)
+                {
+                    PWCHAR pwszTarget = &u.Buf.SymbolicLinkReparseBuffer.PathBuffer[0];
+                    pwszTarget += u.Buf.SymbolicLinkReparseBuffer.SubstituteNameOffset / 2;
+                    pwszTarget[u.Buf.SymbolicLinkReparseBuffer.SubstituteNameLength / 2] = 0;
+                    if (   !(u.Buf.SymbolicLinkReparseBuffer.Flags & MY_SYMLINK_FLAG_RELATIVE)
+                        && pwszTarget[0] == '\\'
+                        && pwszTarget[1] == '?'
+                        && pwszTarget[2] == '?'
+                        && pwszTarget[3] == '\\'
+                        && pwszTarget[4] != 0
+                       )
+                        pwszTarget += 4;
+                    rc = RTUtf16ToUtf8(pwszTarget, ppszTarget);
+                }
+                else
+                    rc = VERR_NOT_SYMLINK;
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+            CloseHandle(hSymlink);
+        }
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+        RTPathWinFree(pwszNativeSymlink);
+    }
+
+    if (RT_SUCCESS(rc))
+        LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc *ppszTarget=%p:{%s}\n", pszSymlink, pszSymlink, ppszTarget, rc, *ppszTarget, *ppszTarget));
+    else
+        LogFlow(("RTSymlinkReadA(%p={%s},%p): returns %Rrc\n", pszSymlink, pszSymlink, ppszTarget, rc));
+    return rc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/system-get-nt-xxx-win.cpp b/src/VBox/Runtime/r3/win/system-get-nt-xxx-win.cpp
new file mode 100644
index 00000000..30088667
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/system-get-nt-xxx-win.cpp
@@ -0,0 +1,68 @@
+/* $Id: system-get-nt-xxx-win.cpp $ */
+/** @file
+ * IPRT - RTSystemQueryOSInfo, generic stub.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/win/windows.h>
+
+#include "internal-r3-win.h"
+#include <iprt/system.h>
+#include <iprt/assert.h>
+
+
+RTDECL(uint32_t) RTSystemGetNtBuildNo(void)
+{
+    Assert(g_WinOsInfoEx.dwOSVersionInfoSize > 0);
+    return g_WinOsInfoEx.dwBuildNumber;
+}
+
+
+RTDECL(uint64_t) RTSystemGetNtVersion(void)
+{
+    Assert(g_WinOsInfoEx.dwOSVersionInfoSize > 0);
+    return RTSYSTEM_MAKE_NT_VERSION(g_WinOsInfoEx.dwMajorVersion, g_WinOsInfoEx.dwMinorVersion, g_WinOsInfoEx.dwBuildNumber);
+}
+
+
+RTDECL(uint8_t) RTSystemGetNtProductType(void)
+{
+    Assert(g_WinOsInfoEx.dwOSVersionInfoSize > 0);
+    return g_WinOsInfoEx.wProductType; /* It's a byte, not a word as 'w' normally indicates. (Baka Maikurosofuto!) */
+}
+
diff --git a/src/VBox/Runtime/r3/win/thread-win.cpp b/src/VBox/Runtime/r3/win/thread-win.cpp
new file mode 100644
index 00000000..80bd3879
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/thread-win.cpp
@@ -0,0 +1,588 @@
+/* $Id: thread-win.cpp $ */
+/** @file
+ * IPRT - Threads, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <iprt/nt/nt-and-windows.h>
+
+#ifndef IPRT_NO_CRT
+# include <errno.h>
+# include <process.h>
+#endif
+
+#include <iprt/thread.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm-amd64-x86.h>
+#include <iprt/assert.h>
+#include <iprt/cpuset.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/param.h>
+#include "internal/thread.h"
+#include "internal-r3-win.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** SetThreadDescription */
+typedef HRESULT (WINAPI *PFNSETTHREADDESCRIPTION)(HANDLE hThread, WCHAR *pwszName); /* Since W10 1607 */
+
+/** CoInitializeEx */
+typedef HRESULT (WINAPI *PFNCOINITIALIZEEX)(LPVOID, DWORD);
+/** CoUninitialize */
+typedef void (WINAPI *PFNCOUNINITIALIZE)(void);
+/** OleUninitialize */
+typedef void (WINAPI *PFNOLEUNINITIALIZE)(void);
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** The TLS index allocated for storing the RTTHREADINT pointer. */
+static DWORD                    g_dwSelfTLS = TLS_OUT_OF_INDEXES;
+/** Pointer to SetThreadDescription (KERNEL32.DLL) if available. */
+static PFNSETTHREADDESCRIPTION  g_pfnSetThreadDescription = NULL;
+
+/** Pointer to CoInitializeEx (OLE32.DLL / combase.dll) if available. */
+static PFNCOINITIALIZEEX volatile   g_pfnCoInitializeEx  = NULL;
+/** Pointer to CoUninitialize (OLE32.DLL / combase.dll) if available. */
+static PFNCOUNINITIALIZE volatile   g_pfnCoUninitialize  = NULL;
+/** Pointer to OleUninitialize (OLE32.DLL / combase.dll) if available. */
+static PFNOLEUNINITIALIZE volatile  g_pfnOleUninitialize = NULL;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static void rtThreadWinTellDebuggerThreadName(uint32_t idThread, const char *pszName);
+DECLINLINE(void) rtThreadWinSetThreadName(PRTTHREADINT pThread, DWORD idThread);
+
+
+DECLHIDDEN(int) rtThreadNativeInit(void)
+{
+    g_dwSelfTLS = TlsAlloc();
+    if (g_dwSelfTLS == TLS_OUT_OF_INDEXES)
+        return VERR_NO_TLS_FOR_SELF;
+
+    g_pfnSetThreadDescription = (PFNSETTHREADDESCRIPTION)GetProcAddress(g_hModKernel32, "SetThreadDescription");
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(void) rtThreadNativeReInitObtrusive(void)
+{
+    /* nothing to do here. */
+}
+
+
+DECLHIDDEN(void) rtThreadNativeDetach(void)
+{
+    /*
+     * Deal with alien threads.
+     */
+    PRTTHREADINT pThread = (PRTTHREADINT)TlsGetValue(g_dwSelfTLS);
+    if (    pThread
+        &&  (pThread->fIntFlags & RTTHREADINT_FLAGS_ALIEN))
+    {
+        rtThreadTerminate(pThread, 0);
+        TlsSetValue(g_dwSelfTLS, NULL);
+    }
+}
+
+
+DECLHIDDEN(void) rtThreadNativeDestroy(PRTTHREADINT pThread)
+{
+    if (pThread == (PRTTHREADINT)TlsGetValue(g_dwSelfTLS))
+        TlsSetValue(g_dwSelfTLS, NULL);
+
+    if ((HANDLE)pThread->hThread != INVALID_HANDLE_VALUE)
+    {
+        CloseHandle((HANDLE)pThread->hThread);
+        pThread->hThread = (uintptr_t)INVALID_HANDLE_VALUE;
+    }
+}
+
+
+DECLHIDDEN(int) rtThreadNativeAdopt(PRTTHREADINT pThread)
+{
+    if (!TlsSetValue(g_dwSelfTLS, pThread))
+        return VERR_FAILED_TO_SET_SELF_TLS;
+    rtThreadWinSetThreadName(pThread, GetCurrentThreadId());
+    return VINF_SUCCESS;
+}
+
+
+DECLHIDDEN(void) rtThreadNativeInformDebugger(PRTTHREADINT pThread)
+{
+    rtThreadWinTellDebuggerThreadName((uint32_t)(uintptr_t)pThread->Core.Key, pThread->szName);
+}
+
+
+/**
+ * Communicates the thread name to the debugger, if we're begin debugged that
+ * is.
+ *
+ * See http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx for debugger
+ * interface details.
+ *
+ * @param   idThread        The thread ID. UINT32_MAX for current thread.
+ * @param   pszName         The name.
+ */
+static void rtThreadWinTellDebuggerThreadName(uint32_t idThread, const char *pszName)
+{
+    struct
+    {
+        uint32_t    uType;
+        const char *pszName;
+        uint32_t    idThread;
+        uint32_t    fFlags;
+    } Pkg = { 0x1000, pszName, idThread, 0 };
+    __try
+    {
+        RaiseException(0x406d1388, 0, sizeof(Pkg)/sizeof(ULONG_PTR), (ULONG_PTR *)&Pkg);
+    }
+    __except(EXCEPTION_CONTINUE_EXECUTION)
+    {
+
+    }
+}
+
+
+/**
+ * Sets the thread name as best as we can.
+ */
+DECLINLINE(void) rtThreadWinSetThreadName(PRTTHREADINT pThread, DWORD idThread)
+{
+    if (g_pfnIsDebuggerPresent && g_pfnIsDebuggerPresent())
+        rtThreadWinTellDebuggerThreadName(idThread, &pThread->szName[0]);
+
+    /* The SetThreadDescription API introduced in windows 10 1607 / server 2016
+       allows setting the thread name while the debugger isn't attached.  Works
+       with WinDbgX, VisualStudio 2017 v15.6+, and presumeably some recent windbg
+       version. */
+    if (g_pfnSetThreadDescription)
+    {
+        /* The name should be ASCII, so we just need to expand 'char' to 'WCHAR'. */
+        WCHAR wszName[RTTHREAD_NAME_LEN];
+        for (size_t i = 0; i < RTTHREAD_NAME_LEN; i++)
+            wszName[i] = pThread->szName[i];
+
+        HRESULT hrc = g_pfnSetThreadDescription(GetCurrentThread(), wszName);
+        Assert(SUCCEEDED(hrc)); RT_NOREF(hrc);
+    }
+}
+
+
+/**
+ * Bitch about dangling COM and OLE references, dispose of them
+ * afterwards so we don't end up deadlocked somewhere below
+ * OLE32!DllMain.
+ */
+static void rtThreadNativeUninitComAndOle(void)
+{
+#if 1 /* experimental code */
+    /*
+     * Read the counters.
+     */
+    struct MySOleTlsData
+    {
+        void       *apvReserved0[2];    /**< x86=0x00  W7/64=0x00 */
+        DWORD       adwReserved0[3];    /**< x86=0x08  W7/64=0x10 */
+        void       *apvReserved1[1];    /**< x86=0x14  W7/64=0x20 */
+        DWORD       cComInits;          /**< x86=0x18  W7/64=0x28 */
+        DWORD       cOleInits;          /**< x86=0x1c  W7/64=0x2c */
+        DWORD       dwReserved1;        /**< x86=0x20  W7/64=0x30 */
+        void       *apvReserved2[4];    /**< x86=0x24  W7/64=0x38 */
+        DWORD       adwReserved2[1];    /**< x86=0x34  W7/64=0x58 */
+        void       *pvCurrentCtx;       /**< x86=0x38  W7/64=0x60 */
+        IUnknown   *pCallState;         /**< x86=0x3c  W7/64=0x68 */
+    }      *pOleTlsData = NULL;         /* outside the try/except for debugging */
+    DWORD   cComInits   = 0;
+    DWORD   cOleInits   = 0;
+    __try
+    {
+        void *pvTeb = NtCurrentTeb();
+# ifdef RT_ARCH_AMD64
+        pOleTlsData = *(struct MySOleTlsData **)((uintptr_t)pvTeb + 0x1758); /*TEB.ReservedForOle*/
+# elif RT_ARCH_X86
+        pOleTlsData = *(struct MySOleTlsData **)((uintptr_t)pvTeb + 0x0f80); /*TEB.ReservedForOle*/
+# else
+#  error "Port me!"
+# endif
+        if (pOleTlsData)
+        {
+            cComInits = pOleTlsData->cComInits;
+            cOleInits = pOleTlsData->cOleInits;
+        }
+    }
+    __except(EXCEPTION_EXECUTE_HANDLER)
+    {
+        AssertFailedReturnVoid();
+    }
+
+    /*
+     * Assert sanity. If any of these breaks, the structure layout above is
+     * probably not correct any longer.
+     */
+    AssertMsgReturnVoid(cComInits < 1000, ("%u (%#x)\n", cComInits, cComInits));
+    AssertMsgReturnVoid(cOleInits < 1000, ("%u (%#x)\n", cOleInits, cOleInits));
+    AssertMsgReturnVoid(cComInits >= cOleInits, ("cComInits=%#x cOleInits=%#x\n", cComInits, cOleInits));
+
+    /*
+     * Do the uninitializing.
+     */
+    if (cComInits)
+    {
+        AssertMsgFailed(("cComInits=%u (%#x) cOleInits=%u (%#x) - dangling COM/OLE inits!\n",
+                         cComInits, cComInits, cOleInits, cOleInits));
+
+        PFNOLEUNINITIALIZE  pfnOleUninitialize = g_pfnOleUninitialize;
+        PFNCOUNINITIALIZE   pfnCoUninitialize  = g_pfnCoUninitialize;
+        if (pfnCoUninitialize && pfnOleUninitialize)
+        { /* likely */ }
+        else
+        {
+            HMODULE hOle32 = GetModuleHandle("ole32.dll");
+            AssertReturnVoid(hOle32 != NULL);
+
+            pfnOleUninitialize = (PFNOLEUNINITIALIZE)GetProcAddress(hOle32, "OleUninitialize");
+            AssertReturnVoid(pfnOleUninitialize);
+
+            pfnCoUninitialize  = (PFNCOUNINITIALIZE)GetProcAddress(hOle32, "CoUninitialize");
+            AssertReturnVoid(pfnCoUninitialize);
+        }
+
+        while (cOleInits-- > 0)
+        {
+            pfnOleUninitialize();
+            cComInits--;
+        }
+
+        while (cComInits-- > 0)
+            pfnCoUninitialize();
+    }
+#endif
+}
+
+
+/**
+ * Implements the RTTHREADFLAGS_COM_MTA and RTTHREADFLAGS_COM_STA flags.
+ *
+ * @returns true if COM uninitialization should be done, false if not.
+ * @param   fFlags      The thread flags.
+ */
+static bool rtThreadNativeWinCoInitialize(unsigned fFlags)
+{
+    /*
+     * Resolve the ole32 init and uninit functions dynamically.
+     */
+    PFNCOINITIALIZEEX pfnCoInitializeEx = g_pfnCoInitializeEx;
+    PFNCOUNINITIALIZE pfnCoUninitialize = g_pfnCoUninitialize;
+    if (pfnCoInitializeEx && pfnCoUninitialize)
+    { /* likely */ }
+    else
+    {
+        RTLDRMOD hModOle32 = NIL_RTLDRMOD;
+        int rc = RTLdrLoadSystem("ole32.dll", true /*fNoUnload*/, &hModOle32);
+        AssertRCReturn(rc, false);
+
+        PFNOLEUNINITIALIZE pfnOleUninitialize;
+        pfnOleUninitialize = (PFNOLEUNINITIALIZE)RTLdrGetFunction(hModOle32, "OleUninitialize");
+        pfnCoUninitialize  = (PFNCOUNINITIALIZE )RTLdrGetFunction(hModOle32, "CoUninitialize");
+        pfnCoInitializeEx  = (PFNCOINITIALIZEEX )RTLdrGetFunction(hModOle32, "CoInitializeEx");
+
+        RTLdrClose(hModOle32);
+        AssertReturn(pfnCoInitializeEx && pfnCoUninitialize, false);
+
+        if (pfnOleUninitialize && !g_pfnOleUninitialize)
+            g_pfnOleUninitialize = pfnOleUninitialize;
+        g_pfnCoInitializeEx = pfnCoInitializeEx;
+        g_pfnCoUninitialize = pfnCoUninitialize;
+    }
+
+    /*
+     * Do the initializating.
+     */
+    DWORD fComInit;
+    if (fFlags & RTTHREADFLAGS_COM_MTA)
+        fComInit = COINIT_MULTITHREADED     | COINIT_SPEED_OVER_MEMORY | COINIT_DISABLE_OLE1DDE;
+    else
+        fComInit = COINIT_APARTMENTTHREADED | COINIT_SPEED_OVER_MEMORY;
+    HRESULT hrc = pfnCoInitializeEx(NULL, fComInit);
+    AssertMsg(SUCCEEDED(hrc), ("%Rhrc fComInit=%#x\n", hrc, fComInit));
+    return SUCCEEDED(hrc);
+}
+
+
+/**
+ * Wrapper which unpacks the param stuff and calls thread function.
+ */
+#ifndef IPRT_NO_CRT
+static unsigned __stdcall rtThreadNativeMain(void *pvArgs) RT_NOTHROW_DEF
+#else
+static DWORD __stdcall rtThreadNativeMain(void *pvArgs) RT_NOTHROW_DEF
+#endif
+{
+    DWORD           dwThreadId = GetCurrentThreadId();
+    PRTTHREADINT    pThread = (PRTTHREADINT)pvArgs;
+
+    if (!TlsSetValue(g_dwSelfTLS, pThread))
+        AssertReleaseMsgFailed(("failed to set self TLS. lasterr=%d thread '%s'\n", GetLastError(), pThread->szName));
+    rtThreadWinSetThreadName(pThread, dwThreadId);
+
+    bool fUninitCom = (pThread->fFlags & (RTTHREADFLAGS_COM_MTA | RTTHREADFLAGS_COM_STA)) != 0;
+    if (fUninitCom)
+        fUninitCom = rtThreadNativeWinCoInitialize(pThread->fFlags);
+
+    int rc = rtThreadMain(pThread, dwThreadId, &pThread->szName[0]);
+
+    TlsSetValue(g_dwSelfTLS, NULL); /* rtThreadMain already released the structure. */
+
+    if (fUninitCom && g_pfnCoUninitialize)
+        g_pfnCoUninitialize();
+
+    rtThreadNativeUninitComAndOle();
+#ifndef IPRT_NO_CRT
+    _endthreadex(rc);
+    return rc; /* not reached */
+#else
+    for (;;)
+        ExitThread(rc);
+#endif
+}
+
+
+DECLHIDDEN(int) rtThreadNativeCreate(PRTTHREADINT pThread, PRTNATIVETHREAD pNativeThread)
+{
+    AssertReturn(pThread->cbStack < ~(unsigned)0, VERR_INVALID_PARAMETER);
+
+    /*
+     * If a stack size is given, make sure it's not a multiple of 64KB so that we
+     * get one or more pages for overflow protection.  (ASSUMES 64KB alloc align.)
+     */
+    unsigned cbStack = (unsigned)pThread->cbStack;
+    if (cbStack > 0 && RT_ALIGN_T(cbStack, _64K, unsigned) == cbStack)
+        cbStack += PAGE_SIZE;
+
+    /*
+     * Create the thread.
+     */
+    pThread->hThread = (uintptr_t)INVALID_HANDLE_VALUE;
+#ifndef IPRT_NO_CRT
+    unsigned    uThreadId = 0;
+    uintptr_t   hThread   = _beginthreadex(NULL /*pSecAttrs*/, cbStack, rtThreadNativeMain, pThread, 0 /*fFlags*/, &uThreadId);
+    if (hThread != 0 && hThread != ~0U)
+    {
+        pThread->hThread = hThread;
+        *pNativeThread = uThreadId;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromErrno(errno);
+#else
+    DWORD  idThread = 0;
+    HANDLE hThread = CreateThread(NULL /*pSecAttrs*/, cbStack, rtThreadNativeMain, pThread, 0 /*fFlags*/, &idThread);
+    if (hThread != NULL)
+    {
+        pThread->hThread = (uintptr_t)hThread;
+        *pNativeThread = idThread;
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(GetLastError());
+#endif
+}
+
+
+DECLHIDDEN(bool) rtThreadNativeIsAliveKludge(PRTTHREADINT pThread)
+{
+    PPEB_COMMON pPeb = NtCurrentPeb();
+    if (!pPeb || !pPeb->Ldr || !pPeb->Ldr->ShutdownInProgress)
+        return true;
+    DWORD rcWait = WaitForSingleObject((HANDLE)pThread->hThread, 0);
+    return rcWait != WAIT_OBJECT_0;
+}
+
+
+RTDECL(RTTHREAD) RTThreadSelf(void)
+{
+    PRTTHREADINT pThread = (PRTTHREADINT)TlsGetValue(g_dwSelfTLS);
+    /** @todo import alien threads ? */
+    return pThread;
+}
+
+
+#if 0 /* noone is using this ... */
+/**
+ * Returns the processor number the current thread was running on during this call
+ *
+ * @returns processor nr
+ */
+static int rtThreadGetCurrentProcessorNumber(void)
+{
+    static bool           fInitialized = false;
+    static DWORD (WINAPI *pfnGetCurrentProcessorNumber)(void) = NULL;
+    if (!fInitialized)
+    {
+        HMODULE hmodKernel32 = GetModuleHandle("kernel32.dll");
+        if (hmodKernel32)
+            pfnGetCurrentProcessorNumber = (DWORD (WINAPI*)(void))GetProcAddress(hmodKernel32, "GetCurrentProcessorNumber");
+        fInitialized = true;
+    }
+    if (pfnGetCurrentProcessorNumber)
+        return pfnGetCurrentProcessorNumber();
+    return -1;
+}
+#endif
+
+
+RTR3DECL(int) RTThreadSetAffinity(PCRTCPUSET pCpuSet)
+{
+    /* The affinity functionality was added in NT 3.50, so we resolve the APIs
+       dynamically to be able to run on NT 3.1. */
+    if (g_pfnSetThreadAffinityMask)
+    {
+        DWORD_PTR fNewMask = pCpuSet ? RTCpuSetToU64(pCpuSet) : ~(DWORD_PTR)0;
+        DWORD_PTR dwRet = g_pfnSetThreadAffinityMask(GetCurrentThread(), fNewMask);
+        if (dwRet)
+            return VINF_SUCCESS;
+
+        int iLastError = GetLastError();
+        AssertMsgFailed(("SetThreadAffinityMask failed, LastError=%d\n", iLastError));
+        return RTErrConvertFromWin32(iLastError);
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTR3DECL(int) RTThreadGetAffinity(PRTCPUSET pCpuSet)
+{
+    /* The affinity functionality was added in NT 3.50, so we resolve the APIs
+       dynamically to be able to run on NT 3.1. */
+    if (   g_pfnSetThreadAffinityMask
+        && g_pfnGetProcessAffinityMask)
+    {
+        /*
+         * Haven't found no query api, but the set api returns the old mask, so let's use that.
+         */
+        DWORD_PTR dwIgnored;
+        DWORD_PTR dwProcAff = 0;
+        if (g_pfnGetProcessAffinityMask(GetCurrentProcess(), &dwProcAff, &dwIgnored))
+        {
+            HANDLE hThread = GetCurrentThread();
+            DWORD_PTR dwRet = g_pfnSetThreadAffinityMask(hThread, dwProcAff);
+            if (dwRet)
+            {
+                DWORD_PTR dwSet = g_pfnSetThreadAffinityMask(hThread, dwRet);
+                Assert(dwSet == dwProcAff); NOREF(dwRet);
+
+                RTCpuSetFromU64(pCpuSet, (uint64_t)dwSet);
+                return VINF_SUCCESS;
+            }
+        }
+
+        int iLastError = GetLastError();
+        AssertMsgFailed(("SetThreadAffinityMask or GetProcessAffinityMask failed, LastError=%d\n", iLastError));
+        return RTErrConvertFromWin32(iLastError);
+    }
+    return VERR_NOT_SUPPORTED;
+}
+
+
+RTR3DECL(int) RTThreadGetExecutionTimeMilli(uint64_t *pKernelTime, uint64_t *pUserTime)
+{
+    uint64_t u64CreationTime, u64ExitTime, u64KernelTime, u64UserTime;
+
+    if (GetThreadTimes(GetCurrentThread(), (LPFILETIME)&u64CreationTime, (LPFILETIME)&u64ExitTime, (LPFILETIME)&u64KernelTime, (LPFILETIME)&u64UserTime))
+    {
+        *pKernelTime = u64KernelTime / 10000;    /* GetThreadTimes returns time in 100 ns units */
+        *pUserTime   = u64UserTime / 10000;    /* GetThreadTimes returns time in 100 ns units */
+        return VINF_SUCCESS;
+    }
+
+    int iLastError = GetLastError();
+    AssertMsgFailed(("GetThreadTimes failed, LastError=%d\n", iLastError));
+    return RTErrConvertFromWin32(iLastError);
+}
+
+
+/**
+ * Gets the native thread handle for a IPRT thread.
+ *
+ * @returns The thread handle. INVALID_HANDLE_VALUE on failure.
+ * @param   hThread     The IPRT thread handle.
+ *
+ * @note    Windows only.
+ * @note    Only valid after parent returns from the thread creation call.
+ */
+RTDECL(uintptr_t) RTThreadGetNativeHandle(RTTHREAD hThread)
+{
+    PRTTHREADINT pThread = rtThreadGet(hThread);
+    if (pThread)
+    {
+        uintptr_t hHandle = pThread->hThread;
+        rtThreadRelease(pThread);
+        return hHandle;
+    }
+    return (uintptr_t)INVALID_HANDLE_VALUE;
+}
+RT_EXPORT_SYMBOL(RTThreadGetNativeHandle);
+
+
+RTDECL(int) RTThreadPoke(RTTHREAD hThread)
+{
+    AssertReturn(hThread != RTThreadSelf(), VERR_INVALID_PARAMETER);
+    if (g_pfnNtAlertThread)
+    {
+        PRTTHREADINT pThread = rtThreadGet(hThread);
+        AssertReturn(pThread, VERR_INVALID_HANDLE);
+
+        NTSTATUS rcNt = g_pfnNtAlertThread((HANDLE)pThread->hThread);
+
+        rtThreadRelease(pThread);
+        if (NT_SUCCESS(rcNt))
+            return VINF_SUCCESS;
+        return RTErrConvertFromNtStatus(rcNt);
+    }
+    return VERR_NOT_IMPLEMENTED;
+}
+
diff --git a/src/VBox/Runtime/r3/win/thread2-win.cpp b/src/VBox/Runtime/r3/win/thread2-win.cpp
new file mode 100644
index 00000000..f9874c96
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/thread2-win.cpp
@@ -0,0 +1,84 @@
+/* $Id: thread2-win.cpp $ */
+/** @file
+ * IPRT - Threads part 2, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <iprt/win/windows.h>
+
+#include <iprt/thread.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm-amd64-x86.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include "internal/thread.h"
+
+
+RTDECL(RTNATIVETHREAD) RTThreadNativeSelf(void)
+{
+    return (RTNATIVETHREAD)GetCurrentThreadId();
+}
+
+
+RTR3DECL(int)   RTThreadSleep(RTMSINTERVAL cMillies)
+{
+    LogFlow(("RTThreadSleep: cMillies=%d\n", cMillies));
+    Sleep(cMillies);
+    LogFlow(("RTThreadSleep: returning %Rrc (cMillies=%d)\n", VINF_SUCCESS, cMillies));
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(int)   RTThreadSleepNoLog(RTMSINTERVAL cMillies)
+{
+    Sleep(cMillies);
+    return VINF_SUCCESS;
+}
+
+
+RTR3DECL(bool) RTThreadYield(void)
+{
+    uint64_t u64TS = ASMReadTSC();
+    Sleep(0);
+    u64TS = ASMReadTSC() - u64TS;
+    bool fRc = u64TS > 1500;
+    LogFlow(("RTThreadYield: returning %d (%llu ticks)\n", fRc, u64TS));
+    return fRc;
+}
+
diff --git a/src/VBox/Runtime/r3/win/time-win.cpp b/src/VBox/Runtime/r3/win/time-win.cpp
new file mode 100644
index 00000000..09e42d8e
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/time-win.cpp
@@ -0,0 +1,228 @@
+/* $Id: time-win.cpp $ */
+/** @file
+ * IPRT - Time, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#include <iprt/nt/nt-and-windows.h>
+
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include "internal/time.h"
+#include "internal-r3-win.h"
+
+/*
+ * Note! The selected time source be the exact same one as we use in kernel land!
+ */
+//#define USE_TICK_COUNT
+//#define USE_PERFORMANCE_COUNTER
+//# define USE_FILE_TIME
+//#if defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
+# define USE_INTERRUPT_TIME
+//#else
+//# define USE_TICK_COUNT
+//#endif
+
+
+
+DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
+{
+#if defined USE_TICK_COUNT
+    /*
+     * This would work if it didn't flip over every 49 (or so) days.
+     */
+    return (uint64_t)GetTickCount() * RT_NS_1MS_64;
+
+#elif defined USE_PERFORMANCE_COUNTER
+    /*
+     * Slow and not derived from InterruptTime.
+     */
+    static LARGE_INTEGER    llFreq;
+    static unsigned         uMult;
+    if (!llFreq.QuadPart)
+    {
+        if (!QueryPerformanceFrequency(&llFreq))
+            return (uint64_t)GetTickCount() * RT_NS_1MS_64;
+        llFreq.QuadPart /=    1000;
+        uMult            = 1000000;     /* no math genius, but this seemed to help avoiding floating point. */
+    }
+
+    LARGE_INTEGER   ll;
+    if (QueryPerformanceCounter(&ll))
+        return (ll.QuadPart * uMult) / llFreq.QuadPart;
+    return (uint64_t)GetTickCount() * RT_NS_1MS_64;
+
+#elif defined USE_FILE_TIME
+    /*
+     * This is SystemTime not InterruptTime.
+     */
+    uint64_t u64; /* manual say larger integer, should be safe to assume it's the same. */
+    GetSystemTimeAsFileTime((LPFILETIME)&u64);
+    return u64 * 100;
+
+#elif defined USE_INTERRUPT_TIME
+    /*
+     * Use interrupt time if we can (not possible on NT 3.1).
+     * Note! We cannot entirely depend on g_enmWinVer here as we're likely to
+     *       get called before IPRT is initialized.  Ditto g_hModNtDll.
+     */
+    static PFNRTLGETINTERRUPTTIMEPRECISE    s_pfnRtlGetInterruptTimePrecise = NULL;
+    static int volatile                     s_iCanUseUserSharedData         = -1;
+    int                                     iCanUseUserSharedData           = s_iCanUseUserSharedData;
+    if (iCanUseUserSharedData != -1)
+    { /* likely */ }
+    else
+    {
+        /* We may be called before g_enmWinVer has been initialized. */
+        if (g_enmWinVer != kRTWinOSType_UNKNOWN)
+            iCanUseUserSharedData = g_enmWinVer > kRTWinOSType_NT310;
+        else
+        {
+            DWORD dwVer = GetVersion();
+            iCanUseUserSharedData = (dwVer & 0xff) != 3 || ((dwVer >> 8) & 0xff) >= 50;
+        }
+        if (iCanUseUserSharedData != 0)
+        {
+            FARPROC pfn = GetProcAddress(g_hModNtDll ? g_hModNtDll : GetModuleHandleW(L"ntdll"), "RtlGetInterruptTimePrecise");
+            if (pfn != NULL)
+            {
+                ASMAtomicWritePtr(&s_pfnRtlGetInterruptTimePrecise, pfn);
+                iCanUseUserSharedData = 42;
+            }
+        }
+        s_iCanUseUserSharedData = iCanUseUserSharedData;
+    }
+
+    if (iCanUseUserSharedData != 0)
+    {
+        LARGE_INTEGER Time;
+        if (iCanUseUserSharedData == 42)
+        {
+            uint64_t iIgnored;
+            Time.QuadPart = s_pfnRtlGetInterruptTimePrecise(&iIgnored);
+        }
+        else
+        {
+            PKUSER_SHARED_DATA pUserSharedData = (PKUSER_SHARED_DATA)MM_SHARED_USER_DATA_VA;
+            do
+            {
+                Time.HighPart = pUserSharedData->InterruptTime.High1Time;
+                Time.LowPart  = pUserSharedData->InterruptTime.LowPart;
+            } while (pUserSharedData->InterruptTime.High2Time != Time.HighPart);
+        }
+
+        return (uint64_t)Time.QuadPart * 100;
+    }
+
+    return (uint64_t)GetTickCount() * RT_NS_1MS_64;
+
+#else
+# error "Must select a method bright guy!"
+#endif
+}
+
+
+RTDECL(uint64_t) RTTimeSystemNanoTS(void)
+{
+    return rtTimeGetSystemNanoTS();
+}
+
+
+RTDECL(uint64_t) RTTimeSystemMilliTS(void)
+{
+    return rtTimeGetSystemNanoTS() / RT_NS_1MS;
+}
+
+
+RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
+{
+    uint64_t u64;
+    AssertCompile(sizeof(u64) == sizeof(FILETIME));
+    if (g_pfnGetSystemTimeAsFileTime)
+        g_pfnGetSystemTimeAsFileTime((LPFILETIME)&u64);
+    else
+    {
+        SYSTEMTIME SysTime = {0};
+        GetSystemTime(&SysTime);
+        BOOL fRet = SystemTimeToFileTime(&SysTime, (LPFILETIME)&u64);
+        Assert(fRet); RT_NOREF(fRet);
+    }
+    return RTTimeSpecSetNtTime(pTime, u64);
+
+}
+
+
+RTDECL(PRTTIMESPEC) RTTimeLocalNow(PRTTIMESPEC pTime)
+{
+    uint64_t u64Local;
+    if (g_pfnGetSystemTimeAsFileTime)
+    {
+        uint64_t u64;
+        AssertCompile(sizeof(u64) == sizeof(FILETIME));
+        g_pfnGetSystemTimeAsFileTime((LPFILETIME)&u64);
+        if (!FileTimeToLocalFileTime((FILETIME const *)&u64, (LPFILETIME)&u64Local))
+            u64Local = u64;
+    }
+    else
+    {
+        SYSTEMTIME SysTime = {0};
+        GetLocalTime(&SysTime);
+        BOOL fRet = SystemTimeToFileTime(&SysTime, (LPFILETIME)&u64Local);
+        Assert(fRet); RT_NOREF(fRet);
+    }
+    return RTTimeSpecSetNtTime(pTime, u64Local);
+}
+
+
+RTDECL(int64_t) RTTimeLocalDeltaNano(void)
+{
+    /*
+     * UTC = local + Tzi.Bias;
+     * The bias is given in minutes.
+     */
+    TIME_ZONE_INFORMATION Tzi;
+    Tzi.Bias = 0;
+    if (GetTimeZoneInformation(&Tzi) != TIME_ZONE_ID_INVALID)
+        return -(int64_t)Tzi.Bias * 60 * RT_NS_1SEC_64;
+    return 0;
+}
+
diff --git a/src/VBox/Runtime/r3/win/time2-win.cpp b/src/VBox/Runtime/r3/win/time2-win.cpp
new file mode 100644
index 00000000..d4f0db06
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/time2-win.cpp
@@ -0,0 +1,164 @@
+/* $Id: time2-win.cpp $ */
+/** @file
+ * IPRT - Time, Windows.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#include <iprt/win/windows.h>
+
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/assert.h>
+#include <iprt/errcore.h>
+#include "internal/time.h"
+
+#include "internal-r3-win.h"
+
+
+RTDECL(int) RTTimeSet(PCRTTIMESPEC pTime)
+{
+    FILETIME    FileTime;
+    SYSTEMTIME  SysTime;
+    if (FileTimeToSystemTime(RTTimeSpecGetNtFileTime(pTime, &FileTime), &SysTime))
+    {
+        if (SetSystemTime(&SysTime))
+            return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTDECL(PRTTIME) RTTimeLocalExplode(PRTTIME pTime, PCRTTIMESPEC pTimeSpec)
+{
+    RTTIMESPEC LocalTime;
+    if (g_pfnSystemTimeToTzSpecificLocalTime)
+    {
+        /*
+         * FileTimeToLocalFileTime does not do the right thing, so we'll have
+         * to convert to system time and SystemTimeToTzSpecificLocalTime instead.
+         *
+         * Note! FileTimeToSystemTime drops resoultion down to milliseconds, thus
+         *       we have to do the offUTC calculation using milliseconds and adjust
+         *       u32Nanosecons by sub milliseconds digits.
+         */
+        SYSTEMTIME SystemTimeIn;
+        FILETIME FileTime;
+        if (FileTimeToSystemTime(RTTimeSpecGetNtFileTime(pTimeSpec, &FileTime), &SystemTimeIn))
+        {
+            SYSTEMTIME SystemTimeOut;
+            if (g_pfnSystemTimeToTzSpecificLocalTime(NULL /* use current TZI */, &SystemTimeIn, &SystemTimeOut))
+            {
+                if (SystemTimeToFileTime(&SystemTimeOut, &FileTime))
+                {
+                    RTTimeSpecSetNtFileTime(&LocalTime, &FileTime);
+                    pTime = RTTimeExplode(pTime, &LocalTime);
+                    if (pTime)
+                    {
+                        pTime->fFlags = (pTime->fFlags & ~RTTIME_FLAGS_TYPE_MASK) | RTTIME_FLAGS_TYPE_LOCAL;
+                        pTime->offUTC = (RTTimeSpecGetMilli(&LocalTime) - RTTimeSpecGetMilli(pTimeSpec)) / RT_MS_1MIN;
+                        pTime->u32Nanosecond += RTTimeSpecGetNano(pTimeSpec) % RT_NS_1MS;
+                    }
+                    return pTime;
+                }
+            }
+        }
+    }
+
+    /*
+     * The fallback is to use the current offset.
+     * (A better fallback would be to use the offset of the same time of the year.)
+     */
+    LocalTime = *pTimeSpec;
+    int64_t cNsUtcOffset = RTTimeLocalDeltaNano();
+    RTTimeSpecAddNano(&LocalTime, cNsUtcOffset);
+    pTime = RTTimeExplode(pTime, &LocalTime);
+    if (pTime)
+    {
+        pTime->fFlags = (pTime->fFlags & ~RTTIME_FLAGS_TYPE_MASK) | RTTIME_FLAGS_TYPE_LOCAL;
+        pTime->offUTC = cNsUtcOffset / RT_NS_1MIN;
+    }
+    return pTime;
+}
+
+
+/**
+ * Gets the delta between UTC and local time at the given time.
+ *
+ * @code
+ *      RTTIMESPEC LocalTime;
+ *      RTTimeNow(&LocalTime);
+ *      RTTimeSpecAddNano(&LocalTime, RTTimeLocalDeltaNanoFor(&LocalTime));
+ * @endcode
+ *
+ * @param   pTimeSpec   The time spec giving the time to get the delta for.
+ * @returns Returns the nanosecond delta between UTC and local time.
+ */
+RTDECL(int64_t) RTTimeLocalDeltaNanoFor(PCRTTIMESPEC pTimeSpec)
+{
+    RTTIMESPEC LocalTime;
+    if (g_pfnSystemTimeToTzSpecificLocalTime)
+    {
+        /*
+         * FileTimeToLocalFileTime does not do the right thing, so we'll have
+         * to convert to system time and SystemTimeToTzSpecificLocalTime instead.
+         *
+         * Note! FileTimeToSystemTime drops resoultion down to milliseconds, thus
+         *       we have to do the offUTC calculation using milliseconds and adjust
+         *       u32Nanosecons by sub milliseconds digits.
+         */
+        SYSTEMTIME SystemTimeIn;
+        FILETIME FileTime;
+        if (FileTimeToSystemTime(RTTimeSpecGetNtFileTime(pTimeSpec, &FileTime), &SystemTimeIn))
+        {
+            SYSTEMTIME SystemTimeOut;
+            if (g_pfnSystemTimeToTzSpecificLocalTime(NULL /* use current TZI */, &SystemTimeIn, &SystemTimeOut))
+            {
+                if (SystemTimeToFileTime(&SystemTimeOut, &FileTime))
+                {
+                    RTTimeSpecSetNtFileTime(&LocalTime, &FileTime);
+
+                    return (RTTimeSpecGetMilli(&LocalTime) - RTTimeSpecGetMilli(pTimeSpec)) * RT_NS_1MS;
+                }
+            }
+        }
+    }
+
+    return RTTimeLocalDeltaNano();
+}
+
diff --git a/src/VBox/Runtime/r3/win/timer-win.cpp b/src/VBox/Runtime/r3/win/timer-win.cpp
new file mode 100644
index 00000000..f8d4a520
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/timer-win.cpp
@@ -0,0 +1,520 @@
+/* $Id: timer-win.cpp $ */
+/** @file
+ * IPRT - Timer.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIMER
+#define _WIN32_WINNT 0x0500
+#include <iprt/win/windows.h>
+
+#include <iprt/timer.h>
+#ifdef USE_CATCH_UP
+# include <iprt/time.h>
+#endif
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/thread.h>
+#include <iprt/log.h>
+#include <iprt/asm.h>
+#include <iprt/semaphore.h>
+#include <iprt/err.h>
+#include "internal/magics.h"
+#include "internal-r3-win.h"
+
+
+/** Define the flag for creating a manual reset timer if not available in the SDK we are compiling with. */
+#ifndef CREATE_WAITABLE_TIMER_MANUAL_RESET
+# define CREATE_WAITABLE_TIMER_MANUAL_RESET    0x00000001
+#endif
+/** Define the flag for high resolution timers, available since Windows 10 RS4 if not available. */
+#ifndef CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
+# define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION 0x00000002
+#endif
+
+
+RT_C_DECLS_BEGIN
+/* from sysinternals. */
+NTSYSAPI LONG NTAPI NtSetTimerResolution(IN ULONG DesiredResolution, IN BOOLEAN SetResolution, OUT PULONG CurrentResolution);
+NTSYSAPI LONG NTAPI NtQueryTimerResolution(OUT PULONG MaximumResolution, OUT PULONG MinimumResolution, OUT PULONG CurrentResolution);
+RT_C_DECLS_END
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/**
+ * The internal representation of a timer handle.
+ */
+typedef struct RTTIMER
+{
+    /** Magic.
+     * This is RTTIMER_MAGIC, but changes to something else before the timer
+     * is destroyed to indicate clearly that thread should exit. */
+    uint32_t volatile       u32Magic;
+    /** Flag indicating the timer is suspended. */
+    bool    volatile        fSuspended;
+    /** Flag indicating that the timer has been destroyed. */
+    bool    volatile        fDestroyed;
+    /** User argument. */
+    void                   *pvUser;
+    /** Callback. */
+    PFNRTTIMER              pfnTimer;
+    /** The current tick. */
+    uint64_t                iTick;
+    /** The timer interval. 0 if one-shot. */
+    uint64_t                u64NanoInterval;
+    /** The first shot interval. 0 if ASAP. */
+    uint64_t volatile       u64NanoFirst;
+    /** Time handle. */
+    HANDLE                  hTimer;
+    /** USE_CATCH_UP: ns time of the next tick.
+     * !USE_CATCH_UP: -uMilliesInterval * 10000 */
+    LARGE_INTEGER           llNext;
+    /** The thread handle of the timer thread. */
+    RTTHREAD                Thread;
+    /** Event semaphore on which the thread is blocked. */
+    RTSEMEVENT              Event;
+    /** The error/status of the timer.
+     * Initially -1, set to 0 when the timer have been successfully started, and
+     * to errno on failure in starting the timer. */
+    volatile int            iError;
+} RTTIMER;
+
+
+
+/**
+ * Timer thread.
+ */
+static DECLCALLBACK(int) rttimerCallback(RTTHREAD hThreadSelf, void *pvArg)
+{
+    PRTTIMER pTimer = (PRTTIMER)(void *)pvArg;
+    Assert(pTimer->u32Magic == RTTIMER_MAGIC);
+
+    /*
+     * Bounce our priority up quite a bit.
+     */
+    if (!SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL))
+    {
+        int rc = GetLastError();
+        AssertMsgFailed(("Failed to set priority class lasterror %d.\n", rc));
+        pTimer->iError = RTErrConvertFromWin32(rc);
+        RTThreadUserSignal(hThreadSelf);
+        return rc;
+    }
+
+    /*
+     * The work loop.
+     */
+    RTThreadUserSignal(hThreadSelf);
+
+    while (     !pTimer->fDestroyed
+           &&   pTimer->u32Magic == RTTIMER_MAGIC)
+    {
+        /*
+         * Wait for a start or destroy event.
+         */
+        if (pTimer->fSuspended)
+        {
+            int rc = RTSemEventWait(pTimer->Event, RT_INDEFINITE_WAIT);
+            if (RT_FAILURE(rc) && rc != VERR_INTERRUPTED)
+            {
+                AssertRC(rc);
+                if (pTimer->fDestroyed)
+                    continue;
+                RTThreadSleep(1000); /* Don't cause trouble! */
+            }
+            if (    pTimer->fSuspended
+                ||  pTimer->fDestroyed)
+                continue;
+        }
+
+        /*
+         * Start the waitable timer.
+         */
+        pTimer->llNext.QuadPart = -(int64_t)pTimer->u64NanoInterval / 100;
+        LARGE_INTEGER ll;
+        if (pTimer->u64NanoFirst)
+        {
+            GetSystemTimeAsFileTime((LPFILETIME)&ll);
+            ll.QuadPart += pTimer->u64NanoFirst / 100;
+            pTimer->u64NanoFirst = 0;
+        }
+        else
+            ll.QuadPart = -(int64_t)pTimer->u64NanoInterval / 100;
+        if (!SetWaitableTimer(pTimer->hTimer, &ll, 0, NULL, NULL, FALSE))
+        {
+            ASMAtomicXchgBool(&pTimer->fSuspended, true);
+            int rc = GetLastError();
+            AssertMsgFailed(("Failed to set timer, lasterr %d.\n", rc));
+            pTimer->iError = RTErrConvertFromWin32(rc);
+            RTThreadUserSignal(hThreadSelf);
+            continue; /* back to suspended mode. */
+        }
+        pTimer->iError = 0;
+        RTThreadUserSignal(hThreadSelf);
+
+        /*
+         * Timer Service Loop.
+         */
+        do
+        {
+            int rc = WaitForSingleObjectEx(pTimer->hTimer, INFINITE, FALSE);
+            if (pTimer->u32Magic != RTTIMER_MAGIC)
+                break;
+            if (rc == WAIT_OBJECT_0)
+            {
+                /*
+                 * Callback the handler.
+                 */
+                pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pTimer->iTick);
+
+                /*
+                 * Rearm the timer handler.
+                 */
+                ll = pTimer->llNext;
+                BOOL fRc = SetWaitableTimer(pTimer->hTimer, &ll, 0, NULL, NULL, FALSE);
+                AssertMsg(fRc || pTimer->u32Magic != RTTIMER_MAGIC, ("last error %d\n", GetLastError())); NOREF(fRc);
+            }
+            else
+            {
+                /*
+                 * We failed during wait, so just signal the destructor and exit.
+                 */
+                int rc2 = GetLastError();
+                RTThreadUserSignal(hThreadSelf);
+                AssertMsgFailed(("Wait on hTimer failed, rc=%d lasterr=%d\n", rc, rc2)); NOREF(rc2);
+                return -1;
+            }
+        } while (RT_LIKELY(   !pTimer->fSuspended
+                           && !pTimer->fDestroyed
+                           &&  pTimer->u32Magic == RTTIMER_MAGIC));
+
+        /*
+         * Disable the timer.
+         */
+        int rc = CancelWaitableTimer (pTimer->hTimer); RT_NOREF(rc);
+        AssertMsg(rc, ("CancelWaitableTimer lasterr=%d\n", GetLastError()));
+
+        /*
+         * ACK any pending suspend request.
+         */
+        if (!pTimer->fDestroyed)
+        {
+            pTimer->iError = 0;
+            RTThreadUserSignal(hThreadSelf);
+        }
+    }
+
+    /*
+     * Exit.
+     */
+    pTimer->iError = 0;
+    RTThreadUserSignal(hThreadSelf);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Tries to set the NT timer resolution to a value matching the given timer interval.
+ *
+ * @returns IPRT status code.
+ * @param   u64NanoInterval             The timer interval in nano seconds.
+ */
+static int rtTimerNtSetTimerResolution(uint64_t u64NanoInterval)
+{
+    /*
+     * On windows we'll have to set the timer resolution before
+     * we start the timer.
+     */
+    ULONG ulMax = UINT32_MAX;
+    ULONG ulMin = UINT32_MAX;
+    ULONG ulCur = UINT32_MAX;
+    ULONG ulReq = (ULONG)(u64NanoInterval / 100);
+    NtQueryTimerResolution(&ulMax, &ulMin, &ulCur);
+    Log(("NtQueryTimerResolution -> ulMax=%lu00ns ulMin=%lu00ns ulCur=%lu00ns\n", ulMax, ulMin, ulCur));
+    if (ulCur > ulMin && ulCur > ulReq)
+    {
+        ulReq = RT_MIN(ulMin, ulReq);
+        if (NtSetTimerResolution(ulReq, TRUE, &ulCur) >= 0)
+            Log(("Changed timer resolution to %lu*100ns.\n", ulReq));
+        else if (NtSetTimerResolution(10000, TRUE, &ulCur) >= 0)
+            Log(("Changed timer resolution to 1ms.\n"));
+        else if (NtSetTimerResolution(20000, TRUE, &ulCur) >= 0)
+            Log(("Changed timer resolution to 2ms.\n"));
+        else if (NtSetTimerResolution(40000, TRUE, &ulCur) >= 0)
+            Log(("Changed timer resolution to 4ms.\n"));
+        else if (ulMin <= 50000 && NtSetTimerResolution(ulMin, TRUE, &ulCur) >= 0)
+            Log(("Changed timer resolution to %lu *100ns.\n", ulMin));
+        else
+        {
+            AssertMsgFailed(("Failed to configure timer resolution!\n"));
+            return VERR_INTERNAL_ERROR;
+        }
+    }
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTTimerCreateEx(PRTTIMER *ppTimer, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMER pfnTimer, void *pvUser)
+{
+    /*
+     * We don't support the fancy MP features.
+     */
+    if (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC)
+        return VERR_NOT_SUPPORTED;
+
+    /*
+     * Create new timer.
+     */
+    int rc = VERR_IPE_UNINITIALIZED_STATUS;
+    PRTTIMER pTimer = (PRTTIMER)RTMemAlloc(sizeof(*pTimer));
+    if (pTimer)
+    {
+        pTimer->u32Magic        = RTTIMER_MAGIC;
+        pTimer->fSuspended      = true;
+        pTimer->fDestroyed      = false;
+        pTimer->Thread          = NIL_RTTHREAD;
+        pTimer->pfnTimer        = pfnTimer;
+        pTimer->pvUser          = pvUser;
+        pTimer->u64NanoInterval = u64NanoInterval;
+
+        rc = RTSemEventCreate(&pTimer->Event);
+        AssertRC(rc);
+        if (RT_SUCCESS(rc))
+        {
+            /*
+             * Create Win32 waitable timer.
+             * We will first try the undocumented CREATE_WAITABLE_TIMER_HIGH_RESOLUTION which
+             * exists since some Windows 10 version (RS4). If this fails we resort to the old
+             * method of setting the timer resolution before creating a timer which will probably
+             * not give us the accuracy for intervals below the system tick resolution.
+             */
+            pTimer->iError = 0;
+            if (g_pfnCreateWaitableTimerExW)
+                pTimer->hTimer = g_pfnCreateWaitableTimerExW(NULL, NULL,
+                                                             CREATE_WAITABLE_TIMER_MANUAL_RESET | CREATE_WAITABLE_TIMER_HIGH_RESOLUTION,
+                                                             TIMER_ALL_ACCESS);
+            if (!pTimer->hTimer)
+            {
+                rc = rtTimerNtSetTimerResolution(u64NanoInterval);
+                if (RT_SUCCESS(rc))
+                    pTimer->hTimer = CreateWaitableTimer(NULL, TRUE, NULL);
+            }
+
+            if (pTimer->hTimer)
+            {
+                /*
+                 * Kick off the timer thread.
+                 */
+                rc = RTThreadCreate(&pTimer->Thread, rttimerCallback, pTimer, 0, RTTHREADTYPE_TIMER, RTTHREADFLAGS_WAITABLE, "Timer");
+                if (RT_SUCCESS(rc))
+                {
+                    /*
+                     * Wait for the timer to successfully create the timer
+                     * If we don't get a response in 10 secs, then we assume we're screwed.
+                     */
+                    rc = RTThreadUserWait(pTimer->Thread, 10000);
+                    if (RT_SUCCESS(rc))
+                    {
+                        rc = pTimer->iError;
+                        if (RT_SUCCESS(rc))
+                        {
+                            *ppTimer = pTimer;
+                            return VINF_SUCCESS;
+                        }
+                    }
+
+                    /* bail out */
+                    ASMAtomicXchgBool(&pTimer->fDestroyed, true);
+                    ASMAtomicXchgU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
+                    RTThreadWait(pTimer->Thread, 45*1000, NULL);
+                    CancelWaitableTimer(pTimer->hTimer);
+                }
+                CloseHandle(pTimer->hTimer);
+            }
+            else
+                rc = RTErrConvertFromWin32(GetLastError());
+            RTSemEventDestroy(pTimer->Event);
+            pTimer->Event = NIL_RTSEMEVENT;
+        }
+
+        RTMemFree(pTimer);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+    return rc;
+}
+
+
+RTR3DECL(int)     RTTimerDestroy(PRTTIMER pTimer)
+{
+    /* NULL is ok. */
+    if (!pTimer)
+        return VINF_SUCCESS;
+
+    int rc = VINF_SUCCESS;
+    AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+    AssertReturn(pTimer->Thread != RTThreadSelf(), VERR_INTERNAL_ERROR);
+
+    /*
+     * Signal that we want the thread to exit.
+     */
+    ASMAtomicWriteBool(&pTimer->fDestroyed, true);
+    ASMAtomicWriteU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
+
+    /*
+     * Suspend the timer if it's running.
+     */
+    if (!pTimer->fSuspended)
+    {
+        LARGE_INTEGER ll = {0};
+        ll.LowPart = 100;
+        rc = SetWaitableTimer(pTimer->hTimer, &ll, 0, NULL, NULL, FALSE);
+        AssertMsg(rc, ("CancelWaitableTimer lasterr=%d\n", GetLastError()));
+    }
+
+    rc = RTSemEventSignal(pTimer->Event);
+    AssertRC(rc);
+
+    /*
+     * Wait for the thread to exit.
+     * And if it don't wanna exit, we'll get kill it.
+     */
+    rc = RTThreadWait(pTimer->Thread, 30 * 1000, NULL);
+    if (RT_FAILURE(rc))
+        TerminateThread((HANDLE)RTThreadGetNative(pTimer->Thread), UINT32_MAX);
+
+    /*
+     * Free resource.
+     */
+    rc = CloseHandle(pTimer->hTimer);
+    AssertMsg(rc, ("CloseHandle lasterr=%d\n", GetLastError()));
+
+    RTSemEventDestroy(pTimer->Event);
+    pTimer->Event = NIL_RTSEMEVENT;
+
+    RTMemFree(pTimer);
+    return rc;
+}
+
+
+RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+    AssertReturn(pTimer->Thread != RTThreadSelf(), VERR_INTERNAL_ERROR);
+
+    RTThreadUserReset(pTimer->Thread);
+
+    /*
+     * Already running?
+     */
+    if (!ASMAtomicXchgBool(&pTimer->fSuspended, false))
+        return VERR_TIMER_ACTIVE;
+    LogFlow(("RTTimerStart: pTimer=%p u64First=%llu u64NanoInterval=%llu\n", pTimer, u64First, pTimer->u64NanoInterval));
+
+    /*
+     * Tell the thread to start servicing the timer.
+     * Wait for it to ACK the request to avoid reset races.
+     */
+    ASMAtomicUoWriteU64(&pTimer->u64NanoFirst, u64First);
+    ASMAtomicUoWriteU64(&pTimer->iTick, 0);
+    int rc = RTSemEventSignal(pTimer->Event);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTThreadUserWait(pTimer->Thread, 45*1000);
+        AssertRC(rc);
+        RTThreadUserReset(pTimer->Thread);
+    }
+    else
+        AssertRC(rc);
+
+    if (RT_FAILURE(rc))
+        ASMAtomicXchgBool(&pTimer->fSuspended, true);
+    return rc;
+}
+
+
+RTDECL(int) RTTimerStop(PRTTIMER pTimer)
+{
+    /*
+     * Validate input.
+     */
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+
+    RTThreadUserReset(pTimer->Thread);
+
+    /*
+     * Already running?
+     */
+    if (ASMAtomicXchgBool(&pTimer->fSuspended, true))
+        return VERR_TIMER_SUSPENDED;
+    LogFlow(("RTTimerStop: pTimer=%p\n", pTimer));
+
+    /*
+     * Tell the thread to stop servicing the timer.
+     */
+    int rc = VINF_SUCCESS;
+    if (RTThreadSelf() != pTimer->Thread)
+    {
+        LARGE_INTEGER ll = {0};
+        ll.LowPart = 100;
+        rc = SetWaitableTimer(pTimer->hTimer, &ll, 0, NULL, NULL, FALSE);
+        AssertMsg(rc, ("SetWaitableTimer lasterr=%d\n", GetLastError()));
+        rc = RTThreadUserWait(pTimer->Thread, 45*1000);
+        AssertRC(rc);
+        RTThreadUserReset(pTimer->Thread);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTTimerChangeInterval(PRTTIMER pTimer, uint64_t u64NanoInterval)
+{
+    AssertPtrReturn(pTimer, VERR_INVALID_POINTER);
+    AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_MAGIC);
+    NOREF(u64NanoInterval);
+    return VERR_NOT_SUPPORTED;
+}
diff --git a/src/VBox/Runtime/r3/win/tls-win.cpp b/src/VBox/Runtime/r3/win/tls-win.cpp
new file mode 100644
index 00000000..5145a266
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/tls-win.cpp
@@ -0,0 +1,230 @@
+/* $Id: tls-win.cpp $ */
+/** @file
+ * IPRT - Thread Local Storage (TLS), Win32.
+ */
+
+/*
+ * Copyright (C) 2008-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_THREAD
+#include <iprt/win/windows.h>
+
+#include <iprt/thread.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/errcore.h>
+#include <iprt/log.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+#include "internal/thread.h"
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct RTTLSWINDTOR
+{
+    RTLISTNODE      ListEntry;
+    DWORD           iTls;
+    PFNRTTLSDTOR    pfnDestructor;
+} RTTLSWINDTOR;
+typedef RTTLSWINDTOR *PRTTLSWINDTOR;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Init once for the list and critical section. */
+static RTONCE               g_Once = RTONCE_INITIALIZER;
+/** Critical section protecting the TLS destructor list. */
+static RTCRITSECTRW         g_CritSect;
+/** List of TLS destrictors (RTTLSWINDTOR).  */
+static RTLISTANCHOR         g_TlsDtorHead;
+/** Number of desturctors in the list (helps putting of initialization). */
+static uint32_t volatile    g_cTlsDtors = 0;
+
+
+/**
+ * @callback_method_impl{FNRTONCE}
+ */
+static DECLCALLBACK(int32_t) rtTlsWinInitLock(void *pvUser)
+{
+    RT_NOREF(pvUser);
+    RTListInit(&g_TlsDtorHead);
+    return RTCritSectRwInit(&g_CritSect);
+}
+
+
+RTR3DECL(RTTLS) RTTlsAlloc(void)
+{
+    AssertCompile(sizeof(RTTLS) >= sizeof(DWORD));
+    DWORD iTls = TlsAlloc();
+    return iTls != TLS_OUT_OF_INDEXES ? (RTTLS)iTls : NIL_RTTLS;
+}
+
+
+RTR3DECL(int) RTTlsAllocEx(PRTTLS piTls, PFNRTTLSDTOR pfnDestructor)
+{
+    int rc;
+    if (!pfnDestructor)
+    {
+        DWORD iTls = TlsAlloc();
+        if (iTls != TLS_OUT_OF_INDEXES)
+        {
+            Assert((RTTLS)iTls != NIL_RTTLS);
+            *piTls = (RTTLS)iTls;
+            Assert((DWORD)*piTls == iTls);
+            rc = VINF_SUCCESS;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+    else
+    {
+        rc = RTOnce(&g_Once, rtTlsWinInitLock, NULL);
+        if (RT_SUCCESS(rc))
+        {
+            PRTTLSWINDTOR pDtor = (PRTTLSWINDTOR)RTMemAlloc(sizeof(*pDtor));
+            if (pDtor)
+            {
+                DWORD iTls = TlsAlloc();
+                if (iTls != TLS_OUT_OF_INDEXES)
+                {
+                    Assert((RTTLS)iTls != NIL_RTTLS);
+                    *piTls = (RTTLS)iTls;
+                    Assert((DWORD)*piTls == iTls);
+
+                    /*
+                     * Add the destructor to the list.  We keep it sorted.
+                     */
+                    pDtor->iTls = iTls;
+                    pDtor->pfnDestructor = pfnDestructor;
+                    RTCritSectRwEnterExcl(&g_CritSect);
+                    RTListAppend(&g_TlsDtorHead, &pDtor->ListEntry);
+                    ASMAtomicIncU32(&g_cTlsDtors);
+                    RTCritSectRwLeaveExcl(&g_CritSect);
+
+                    rc = VINF_SUCCESS;
+                }
+                else
+                    rc = VERR_NO_MEMORY;
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+    }
+    return rc;
+}
+
+
+RTR3DECL(int) RTTlsFree(RTTLS iTls)
+{
+    if (iTls == NIL_RTTLS)
+        return VINF_SUCCESS;
+    if (TlsFree((DWORD)iTls))
+    {
+        if (ASMAtomicReadU32(&g_cTlsDtors) > 0)
+        {
+            RTCritSectRwEnterExcl(&g_CritSect);
+            PRTTLSWINDTOR pDtor;
+            RTListForEach(&g_TlsDtorHead, pDtor, RTTLSWINDTOR, ListEntry)
+            {
+                if (pDtor->iTls == (DWORD)iTls)
+                {
+                    RTListNodeRemove(&pDtor->ListEntry);
+                    ASMAtomicDecU32(&g_cTlsDtors);
+                    RTMemFree(pDtor);
+                    break;
+                }
+            }
+            RTCritSectRwLeaveExcl(&g_CritSect);
+        }
+        return VINF_SUCCESS;
+    }
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTR3DECL(void *) RTTlsGet(RTTLS iTls)
+{
+    return TlsGetValue((DWORD)iTls);
+}
+
+
+RTR3DECL(int) RTTlsGetEx(RTTLS iTls, void **ppvValue)
+{
+    void *pv = TlsGetValue((DWORD)iTls);
+    if (pv)
+    {
+        *ppvValue = pv;
+        return VINF_SUCCESS;
+    }
+
+    /* TlsGetValue always updates last error */
+    *ppvValue = NULL;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+RTR3DECL(int) RTTlsSet(RTTLS iTls, void *pvValue)
+{
+    if (TlsSetValue((DWORD)iTls, pvValue))
+        return VINF_SUCCESS;
+    return RTErrConvertFromWin32(GetLastError());
+}
+
+
+/**
+ * Called by dllmain-win.cpp when a thread detaches.
+ */
+DECLHIDDEN(void) rtThreadWinTlsDestruction(void)
+{
+    if (ASMAtomicReadU32(&g_cTlsDtors) > 0)
+    {
+        RTCritSectRwEnterShared(&g_CritSect);
+        PRTTLSWINDTOR pDtor;
+        RTListForEach(&g_TlsDtorHead, pDtor, RTTLSWINDTOR, ListEntry)
+        {
+            void *pvValue = TlsGetValue(pDtor->iTls);
+            if (pvValue != NULL)
+            {
+                pDtor->pfnDestructor(pvValue);
+                TlsSetValue(pDtor->iTls, NULL);
+            }
+        }
+        RTCritSectRwLeaveShared(&g_CritSect);
+    }
+}
+
diff --git a/src/VBox/Runtime/r3/win/tpm-win.cpp b/src/VBox/Runtime/r3/win/tpm-win.cpp
new file mode 100644
index 00000000..3ee0e46b
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/tpm-win.cpp
@@ -0,0 +1,307 @@
+/* $Id: tpm-win.cpp $ */
+/** @file
+ * IPRT - Trusted Platform Module (TPM) access, Windows variant.
+ */
+
+/*
+ * Copyright (C) 2021-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_DEFAULT
+#include <iprt/tpm.h>
+
+#include <iprt/assertcompile.h>
+#include <iprt/asm.h>
+#include <iprt/err.h>
+#include <iprt/ldr.h>
+#include <iprt/mem.h>
+#include <iprt/once.h>
+
+#include "internal-r3-win.h"
+
+#include <iprt/win/windows.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/* tbs.dll: */
+typedef struct TBS_CONTEXT_PARAMS2
+{
+    UINT32 version;
+    union
+    {
+        struct
+        {
+            UINT32 requestRaw:   1;
+            UINT32 includeTpm12: 1;
+            UINT32 includeTpm20: 1;
+        } Fields;
+
+        UINT32 asUINT32;
+    } u;
+} TBS_CONTEXT_PARAMS2;
+
+typedef struct TBS_DEVICE_INFO
+{
+    UINT32 structVersion;
+    UINT32 tpmVersion;
+    UINT32 tpmInterfaceType;
+    UINT32 tpmImpRevision;
+} TBS_DEVICE_INFO;
+
+#define TPM_VERSION_12 1
+#define TPM_VERSION_20 2
+
+#define TBS_SUCCESS                 S_OK
+#define TBS_COMMAND_PRIORITY_NORMAL 200
+
+typedef UINT32 TBS_RESULT;
+typedef void *TBS_HCONTEXT;
+typedef TBS_RESULT  (WINAPI *PFNTBSI_CONTEXT_CREATE)(const TBS_CONTEXT_PARAMS2 *, TBS_HCONTEXT *);
+typedef TBS_RESULT  (WINAPI *PFNTBSI_CONTEXT_CLOSE)(TBS_HCONTEXT);
+typedef TBS_RESULT  (WINAPI *PFNTBSI_GET_DEVICE_INFO)(UINT32, TBS_DEVICE_INFO *);
+typedef TBS_RESULT  (WINAPI *PFNTBSI_CANCEL_COMMANDS)(TBS_HCONTEXT);
+typedef TBS_RESULT  (WINAPI *PFNTBSI_SUBMIT_COMMANDS)(TBS_HCONTEXT, UINT32, UINT32, const BYTE *, UINT32, PBYTE, PUINT32);
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+
+/**
+ * Internal TPM instance data.
+ */
+typedef struct RTTPMINT
+{
+    /** Handle to the TPM context. */
+    TBS_HCONTEXT                hCtx;
+    /** The deduced TPM version. */
+    RTTPMVERSION                enmTpmVers;
+} RTTPMINT;
+/** Pointer to the internal TPM instance data. */
+typedef RTTPMINT *PRTTPMINT;
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Init once structure. */
+static RTONCE                   g_rtTpmWinInitOnce              = RTONCE_INITIALIZER;
+/* tbs.dll: */
+static PFNTBSI_CONTEXT_CREATE   g_pfnTbsiContextCreate  = NULL;
+static PFNTBSI_CONTEXT_CLOSE    g_pfnTbsiContextClose   = NULL;
+static PFNTBSI_GET_DEVICE_INFO  g_pfnTbsiGetDeviceInfo  = NULL;
+static PFNTBSI_CANCEL_COMMANDS  g_pfnTbsiCancelCommands = NULL;
+static PFNTBSI_SUBMIT_COMMANDS  g_pfnTbsiSubmitCommands = NULL;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+/**
+ * Initialize the globals.
+ *
+ * @returns IPRT status code.
+ * @param   pvUser              Ignored.
+ */
+static DECLCALLBACK(int32_t) rtTpmWinInitOnce(void *pvUser)
+{
+    RT_NOREF(pvUser);
+    RTLDRMOD hMod;
+
+    int rc = RTLdrLoadSystem("tbs.dll", true /*fNoUnload*/, &hMod);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTLdrGetSymbol(hMod, "Tbsi_Context_Create", (void **)&g_pfnTbsiContextCreate);
+        if (RT_FAILURE(rc)) return rc;
+
+        rc = RTLdrGetSymbol(hMod, "Tbsip_Context_Close", (void **)&g_pfnTbsiContextClose);
+        if (RT_FAILURE(rc)) return rc;
+
+        rc = RTLdrGetSymbol(hMod, "Tbsip_Cancel_Commands", (void **)&g_pfnTbsiCancelCommands);
+        if (RT_FAILURE(rc)) return rc;
+
+        rc = RTLdrGetSymbol(hMod, "Tbsip_Submit_Command", (void **)&g_pfnTbsiSubmitCommands);
+        if (RT_FAILURE(rc)) return rc;
+
+        rc = RTLdrGetSymbol(hMod, "Tbsi_GetDeviceInfo", (void **)&g_pfnTbsiGetDeviceInfo);
+        if (RT_FAILURE(rc)) { g_pfnTbsiGetDeviceInfo = NULL; Assert(g_enmWinVer < kRTWinOSType_8); }
+
+        RTLdrClose(hMod);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTTpmOpen(PRTTPM phTpm, uint32_t idTpm)
+{
+    AssertPtrReturn(phTpm, VERR_INVALID_POINTER);
+    if (idTpm == RTTPM_ID_DEFAULT)
+        idTpm = 0;
+
+    AssertReturn(idTpm == 0, VERR_NOT_SUPPORTED);
+
+    /*
+     * Initialize the globals.
+     */
+    int rc = RTOnce(&g_rtTpmWinInitOnce, rtTpmWinInitOnce, NULL);
+    AssertRCReturn(rc, rc);
+
+    PRTTPMINT pThis = (PRTTPMINT)RTMemAllocZ(sizeof(*pThis));
+    if (pThis)
+    {
+        TBS_CONTEXT_PARAMS2 CtxParams; RT_ZERO(CtxParams);
+
+        CtxParams.version = TPM_VERSION_12;
+        if (g_pfnTbsiGetDeviceInfo)
+        {
+            /* TPM2 support is available starting with Win8 which has Tbsi_GetDeviceInfo available. */
+            TBS_DEVICE_INFO DevInfo; RT_ZERO(DevInfo);
+
+            DevInfo.structVersion = TPM_VERSION_20;
+            TBS_RESULT rcTbs = g_pfnTbsiGetDeviceInfo(sizeof(DevInfo), &DevInfo);
+            if (rcTbs == TBS_SUCCESS)
+            {
+                CtxParams.version = TPM_VERSION_20;
+                if (DevInfo.tpmVersion == TPM_VERSION_20)
+                {
+                    pThis->enmTpmVers = RTTPMVERSION_2_0;
+                    CtxParams.u.Fields.includeTpm20 = 1;
+                }
+                else
+                {
+                    Assert(DevInfo.tpmVersion == TPM_VERSION_12);
+                    pThis->enmTpmVers = RTTPMVERSION_1_2;
+                    CtxParams.u.Fields.includeTpm12 = 1;
+                }
+            }
+            else
+                rc = VERR_NOT_FOUND;
+        }
+        else
+            pThis->enmTpmVers = RTTPMVERSION_1_2;
+
+        if (RT_SUCCESS(rc))
+        {
+            TBS_RESULT rcTbs = g_pfnTbsiContextCreate(&CtxParams, &pThis->hCtx);
+            if (rcTbs == TBS_SUCCESS)
+            {
+                *phTpm = pThis;
+                return VINF_SUCCESS;
+            }
+            else
+                rc = VERR_NOT_FOUND;
+        }
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTTpmClose(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+
+    TBS_RESULT rcTbs = g_pfnTbsiContextClose(pThis->hCtx);
+    Assert(rcTbs == TBS_SUCCESS); RT_NOREF(rcTbs);
+
+    RTMemFree(pThis);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(RTTPMVERSION) RTTpmGetVersion(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, RTTPMVERSION_INVALID);
+    return pThis->enmTpmVers;
+}
+
+
+RTDECL(uint32_t) RTTpmGetLocalityMax(RTTPM hTpm)
+{
+    RT_NOREF(hTpm);
+    return 0; /* Only TPM locality 0 is supported. */
+}
+
+
+RTDECL(int) RTTpmReqCancel(RTTPM hTpm)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+
+    TBS_RESULT rcTbs = g_pfnTbsiCancelCommands(pThis->hCtx);
+    if (rcTbs != TBS_SUCCESS)
+        return VERR_DEV_IO_ERROR;
+
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTTpmReqExec(RTTPM hTpm, uint8_t bLoc, const void *pvReq, size_t cbReq,
+                         void *pvResp, size_t cbRespMax, size_t *pcbResp)
+{
+    PRTTPMINT pThis = hTpm;
+
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pvReq, VERR_INVALID_POINTER);
+    AssertPtrReturn(pvResp, VERR_INVALID_POINTER);
+    AssertReturn(cbReq && cbRespMax, VERR_INVALID_PARAMETER);
+    AssertReturn(cbReq == (UINT32)cbReq && cbRespMax == (UINT32)cbRespMax, VERR_BUFFER_OVERFLOW);
+    AssertReturn(bLoc == 0, VERR_NOT_SUPPORTED); /* TBS doesn't support another locality than 0. */
+
+    UINT32 cbResult = (UINT32)cbRespMax;
+    TBS_RESULT rcTbs = g_pfnTbsiSubmitCommands(pThis->hCtx, 0 /*Locality*/, TBS_COMMAND_PRIORITY_NORMAL,
+                                               (const BYTE *)pvReq, (UINT32)cbReq, (BYTE *)pvResp, &cbResult);
+    if (rcTbs == TBS_SUCCESS)
+    {
+        if (pcbResp)
+            *pcbResp = cbResult;
+        return VINF_SUCCESS;
+    }
+
+    return VERR_DEV_IO_ERROR;
+}
+
diff --git a/src/VBox/Runtime/r3/win/utf16locale-win.cpp b/src/VBox/Runtime/r3/win/utf16locale-win.cpp
new file mode 100644
index 00000000..d282572a
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/utf16locale-win.cpp
@@ -0,0 +1,58 @@
+/* $Id: utf16locale-win.cpp $ */
+/** @file
+ * IPRT - UTF-16 Locale Specific Manipulation, Win32.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_UTF16
+#include <iprt/win/windows.h>
+
+#include <iprt/utf16.h>
+
+
+RTDECL(int) RTUtf16LocaleICmp(PCRTUTF16 pusz1, PCRTUTF16 pusz2)
+{
+    if (pusz1 == pusz2)
+        return 0;
+    if (pusz1 == NULL)
+        return -1;
+    if (pusz2 == NULL)
+        return 1;
+
+    return CompareStringW(LOCALE_USER_DEFAULT, NORM_IGNORECASE, pusz1, -1, pusz2, -1) - 2;
+}
+
diff --git a/src/VBox/Runtime/r3/win/utf8-win.cpp b/src/VBox/Runtime/r3/win/utf8-win.cpp
new file mode 100644
index 00000000..7defa137
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/utf8-win.cpp
@@ -0,0 +1,204 @@
+/* $Id: utf8-win.cpp $ */
+/** @file
+ * IPRT - UTF8 helpers.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_UTF8
+#include <iprt/win/windows.h>
+
+#include <iprt/string.h>
+#include <iprt/alloc.h>
+#include <iprt/assert.h>
+#include <iprt/err.h>
+#include <iprt/utf16.h>
+
+
+
+RTR3DECL(int)  RTStrUtf8ToCurrentCPTag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    return RTStrUtf8ToCurrentCPExTag(ppszString, pszString, RTSTR_MAX, pszTag);
+}
+
+
+RTR3DECL(int)  RTStrUtf8ToCurrentCPExTag(char **ppszString, const char *pszString, size_t cchString, const char *pszTag)
+{
+    Assert(ppszString);
+    Assert(pszString);
+    *ppszString = NULL;
+
+    /*
+     * If the ANSI codepage (CP_ACP) is UTF-8, no translation is needed.
+     * Same goes for empty strings.
+     */
+    if (   cchString == 0
+        || *pszString == '\0')
+        return RTStrDupNExTag(ppszString, pszString, 0, pszTag);
+    if (GetACP() == CP_UTF8)
+    {
+        int rc = RTStrValidateEncodingEx(pszString, cchString, 0);
+        AssertRCReturn(rc, rc);
+        return RTStrDupNExTag(ppszString, pszString, cchString, pszTag);
+    }
+
+    /*
+     * Convert to wide char first.
+     */
+    PRTUTF16 pwszString = NULL;
+    int rc = RTStrToUtf16Ex(pszString, cchString, &pwszString, 0, NULL);
+    if (RT_FAILURE(rc))
+        return rc;
+
+    /*
+     * First calc result string length.
+     */
+    int cbResult = WideCharToMultiByte(CP_ACP, 0, pwszString, -1, NULL, 0, NULL, NULL);
+    if (cbResult > 0)
+    {
+        /*
+         * Alloc space for result buffer.
+         */
+        LPSTR lpString = (LPSTR)RTMemTmpAllocTag(cbResult, pszTag);
+        if (lpString)
+        {
+            /*
+             * Do the translation.
+             */
+            if (WideCharToMultiByte(CP_ACP, 0, pwszString, -1, lpString, cbResult, NULL, NULL) > 0)
+            {
+                /* ok */
+                *ppszString = lpString;
+                RTMemTmpFree(pwszString);
+                return VINF_SUCCESS;
+            }
+
+            /* translation error */
+            int iLastErr = GetLastError();
+            AssertMsgFailed(("Unicode to ACP translation failed. lasterr=%d\n", iLastErr));
+            rc = RTErrConvertFromWin32(iLastErr);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+        RTMemTmpFree(lpString);
+    }
+    else
+    {
+        /* translation error */
+        int iLastErr = GetLastError();
+        AssertMsgFailed(("Unicode to ACP translation failed lasterr=%d\n", iLastErr));
+        rc = RTErrConvertFromWin32(iLastErr);
+    }
+    RTMemTmpFree(pwszString);
+    return rc;
+}
+
+static int rtStrCPToUtf8Tag(char **ppszString, const char *pszString, uint32_t uCodePage, const char *pszTag)
+{
+    Assert(ppszString);
+    Assert(pszString);
+    *ppszString = NULL;
+
+    /*
+     * If the ANSI codepage (CP_ACP) is UTF-8, no translation is needed.
+     * Same goes for empty strings.
+     */
+    if (*pszString == '\0')
+        return RTStrDupExTag(ppszString, pszString, pszTag);
+    if (GetACP() == CP_UTF8)
+    {
+        int rc = RTStrValidateEncoding(pszString);
+        AssertRCReturn(rc, rc);
+        return RTStrDupExTag(ppszString, pszString, pszTag);
+    }
+
+    /** @todo is there a quicker way? Currently: ACP -> UTF-16 -> UTF-8 */
+
+    /*
+     * First calc result string length.
+     */
+    int rc;
+    int cwc = MultiByteToWideChar((UINT)uCodePage, 0, pszString, -1, NULL, 0);
+    if (cwc > 0)
+    {
+        /*
+         * Alloc space for result buffer.
+         */
+        PRTUTF16 pwszString = (PRTUTF16)RTMemTmpAlloc(cwc * sizeof(RTUTF16));
+        if (pwszString)
+        {
+            /*
+             * Do the translation.
+             */
+            if (MultiByteToWideChar((UINT)uCodePage, 0, pszString, -1, pwszString, cwc) > 0)
+            {
+                /*
+                 * Now we got UTF-16, convert it to UTF-8
+                 */
+                rc = RTUtf16ToUtf8(pwszString, ppszString);
+                RTMemTmpFree(pwszString);
+                return rc;
+            }
+            RTMemTmpFree(pwszString);
+            /* translation error */
+            int iLastErr = GetLastError();
+            AssertMsgFailed(("ACP to Unicode translation failed. lasterr=%d\n", iLastErr));
+            rc = RTErrConvertFromWin32(iLastErr);
+        }
+        else
+            rc = VERR_NO_TMP_MEMORY;
+    }
+    else
+    {
+        /* translation error */
+        int iLastErr = GetLastError();
+        AssertMsgFailed(("Unicode to ACP translation failed lasterr=%d\n", iLastErr));
+        rc = RTErrConvertFromWin32(iLastErr);
+    }
+    return rc;
+}
+
+
+RTR3DECL(int)  RTStrCurrentCPToUtf8Tag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    return rtStrCPToUtf8Tag(ppszString, pszString, CP_ACP, pszTag);
+}
+
+
+RTR3DECL(int)  RTStrConsoleCPToUtf8Tag(char **ppszString, const char *pszString, const char *pszTag)
+{
+    return rtStrCPToUtf8Tag(ppszString, pszString, GetConsoleCP(), pszTag);
+}
diff --git a/src/VBox/Runtime/r3/win/uuid-win.cpp b/src/VBox/Runtime/r3/win/uuid-win.cpp
new file mode 100644
index 00000000..eebeb0c0
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/uuid-win.cpp
@@ -0,0 +1,195 @@
+/* $Id: uuid-win.cpp $ */
+/** @file
+ * IPRT - UUID, Windows implementation.
+ */
+
+/*
+ * Copyright (C) 2006-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_UUID
+#include <iprt/win/windows.h>
+
+#include <iprt/uuid.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#include <iprt/errcore.h>
+
+
+RTDECL(int)  RTUuidClear(PRTUUID pUuid)
+{
+    /* check params */
+    AssertPtrReturn(pUuid, VERR_INVALID_POINTER);
+
+    return RTErrConvertFromWin32(UuidCreateNil((UUID *)pUuid));
+}
+
+
+RTDECL(bool)  RTUuidIsNull(PCRTUUID pUuid)
+{
+    /* check params */
+    AssertPtrReturn(pUuid, true);
+
+    RPC_STATUS status;
+    return !!UuidIsNil((UUID *)pUuid, &status);
+}
+
+
+RTDECL(int)  RTUuidCompare(PCRTUUID pUuid1, PCRTUUID pUuid2)
+{
+    /*
+     * Special cases.
+     */
+    if (pUuid1 == pUuid2)
+        return 0;
+    if (!pUuid1)
+        return RTUuidIsNull(pUuid2) ? 0 : -1;
+    if (!pUuid2)
+        return RTUuidIsNull(pUuid1) ? 0 : 1;
+    AssertPtrReturn(pUuid1, -1);
+    AssertPtrReturn(pUuid2, 1);
+
+    /*
+     * Hand the rest to the Windows API.
+     */
+    RPC_STATUS status;
+    return UuidCompare((UUID *)pUuid1, (UUID *)pUuid2, &status);
+}
+
+
+RTDECL(int)  RTUuidCompareStr(PCRTUUID pUuid1, const char *pszString2)
+{
+    /* check params */
+    AssertPtrReturn(pUuid1, -1);
+    AssertPtrReturn(pszString2, 1);
+
+    /*
+     * Try convert the string to a UUID and then compare the two.
+     */
+    RTUUID Uuid2;
+    int rc = RTUuidFromStr(&Uuid2, pszString2);
+    AssertRCReturn(rc, 1);
+
+    return RTUuidCompare(pUuid1, &Uuid2);
+}
+
+
+RTDECL(int)  RTUuidCompare2Strs(const char *pszString1, const char *pszString2)
+{
+    RTUUID Uuid1;
+    RTUUID Uuid2;
+    int rc;
+
+    /* check params */
+    AssertPtrReturn(pszString1, -1);
+    AssertPtrReturn(pszString2, 1);
+
+    /*
+     * Try convert the strings to UUIDs and then compare them.
+     */
+    rc = RTUuidFromStr(&Uuid1, pszString1);
+    AssertRCReturn(rc, -1);
+
+    rc = RTUuidFromStr(&Uuid2, pszString2);
+    AssertRCReturn(rc, 1);
+
+    return RTUuidCompare(&Uuid1, &Uuid2);
+}
+
+
+RTDECL(int)  RTUuidToStr(PCRTUUID pUuid, char *pszString, size_t cchString)
+{
+    /* check params */
+    AssertPtrReturn(pUuid, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszString, VERR_INVALID_POINTER);
+    AssertReturn(cchString >= RTUUID_STR_LENGTH, VERR_INVALID_PARAMETER);
+
+    /*
+     * Try convert it.
+     *
+     * The API allocates a new string buffer for us, so we can do our own
+     * buffer overflow handling.
+     */
+    RPC_STATUS Status;
+    unsigned char *pszTmpStr = NULL;
+#ifdef RPC_UNICODE_SUPPORTED
+    /* always use ASCII version! */
+    Status = UuidToStringA((UUID *)pUuid, &pszTmpStr);
+#else
+    Status = UuidToString((UUID *)pUuid, &pszTmpStr);
+#endif
+    if (Status != RPC_S_OK)
+        return RTErrConvertFromWin32(Status);
+
+    /* copy it. */
+    int rc = VINF_SUCCESS;
+    size_t cchTmpStr = strlen((char *)pszTmpStr);
+    if (cchTmpStr < cchString)
+        memcpy(pszString, pszTmpStr, cchTmpStr + 1);
+    else
+    {
+        AssertFailed();
+        rc = ERROR_BUFFER_OVERFLOW;
+    }
+
+    /* free buffer */
+#ifdef RPC_UNICODE_SUPPORTED
+    /* always use ASCII version! */
+    RpcStringFreeA(&pszTmpStr);
+#else
+    RpcStringFree(&pszTmpStr);
+#endif
+
+    /* all done */
+    return rc;
+}
+
+
+RTDECL(int)  RTUuidFromStr(PRTUUID pUuid, const char *pszString)
+{
+    /* check params */
+    AssertPtrReturn(pUuid, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszString, VERR_INVALID_POINTER);
+
+    RPC_STATUS rc;
+#ifdef RPC_UNICODE_SUPPORTED
+    /* always use ASCII version! */
+    rc = UuidFromStringA((unsigned char *)pszString, (UUID *)pUuid);
+#else
+    rc = UuidFromString((unsigned char *)pszString, (UUID *)pUuid);
+#endif
+
+    return RTErrConvertFromWin32(rc);
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-100.h b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-100.h
new file mode 100644
index 00000000..1708ee52
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-100.h
@@ -0,0 +1,43 @@
+
+COMMENT("XP SP2 / W2K3 SP1 / VISTA")
+MAKE_IMPORT_ENTRY(6,0, DecodePointer, 4)
+MAKE_IMPORT_ENTRY(6,0, EncodePointer, 4)
+COMMENT("XP")
+MAKE_IMPORT_ENTRY(5,1, CreateIoCompletionPort, 16)
+MAKE_IMPORT_ENTRY(5,1, GetQueuedCompletionStatus, 20)
+MAKE_IMPORT_ENTRY(5,1, HeapSetInformation, 16)
+MAKE_IMPORT_ENTRY(5,1, HeapQueryInformation, 20)
+MAKE_IMPORT_ENTRY(5,1, InitializeSListHead, 4)
+MAKE_IMPORT_ENTRY(5,1, InterlockedFlushSList, 4)
+MAKE_IMPORT_ENTRY(5,1, InterlockedPopEntrySList, 4)
+MAKE_IMPORT_ENTRY(5,1, InterlockedPushEntrySList, 8)
+MAKE_IMPORT_ENTRY(5,1, PostQueuedCompletionStatus, 16)
+MAKE_IMPORT_ENTRY(5,1, QueryDepthSList, 4)
+COMMENT("W2K")
+MAKE_IMPORT_ENTRY(5,0, CreateTimerQueue, 0)
+MAKE_IMPORT_ENTRY(5,0, CreateTimerQueueTimer, 28)
+MAKE_IMPORT_ENTRY(5,0, DeleteTimerQueueTimer, 12)
+MAKE_IMPORT_ENTRY(5,0, VerSetConditionMask, 16)
+COMMENT("NT 4 SP4+")
+MAKE_IMPORT_ENTRY(5,0, VerifyVersionInfoA, 16)
+COMMENT("NT 4 SP3+")
+MAKE_IMPORT_ENTRY(5,0, InitializeCriticalSectionAndSpinCount, 8)
+COMMENT("NT 4")
+MAKE_IMPORT_ENTRY(4,0, IsProcessorFeaturePresent, 4)
+MAKE_IMPORT_ENTRY(4,0, CancelIo, 4)
+COMMENT("NT 3.51")
+MAKE_IMPORT_ENTRY(3,51, IsDebuggerPresent, 0)
+MAKE_IMPORT_ENTRY(3,51, GetSystemTimeAsFileTime, 4)
+COMMENT("NT 3.50")
+MAKE_IMPORT_ENTRY(3,50, GetVersionExA, 4)
+MAKE_IMPORT_ENTRY(3,50, GetVersionExW, 4)
+MAKE_IMPORT_ENTRY(3,50, GetEnvironmentStringsW, 0)
+MAKE_IMPORT_ENTRY(3,50, FreeEnvironmentStringsW, 4)
+MAKE_IMPORT_ENTRY(3,50, GetLocaleInfoA, 16)
+MAKE_IMPORT_ENTRY(3,50, EnumSystemLocalesA, 8)
+MAKE_IMPORT_ENTRY(3,50, IsValidLocale, 8)
+MAKE_IMPORT_ENTRY(3,50, SetThreadAffinityMask, 8)
+MAKE_IMPORT_ENTRY(3,50, GetProcessAffinityMask, 12)
+MAKE_IMPORT_ENTRY(3,50, GetHandleInformation, 8)
+MAKE_IMPORT_ENTRY(3,50, SetHandleInformation, 12)
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-141.h b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-141.h
new file mode 100644
index 00000000..a65e6392
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-141.h
@@ -0,0 +1,42 @@
+MAKE_IMPORT_ENTRY(6,0, DecodePointer, 4)
+MAKE_IMPORT_ENTRY(6,0, EncodePointer, 4)
+MAKE_IMPORT_ENTRY(5,1, InitializeSListHead, 4)
+MAKE_IMPORT_ENTRY(5,1, GetModuleHandleExW, 12)
+MAKE_IMPORT_ENTRY(5,0, VerifyVersionInfoA, 16)
+MAKE_IMPORT_ENTRY(5,0, SetFilePointerEx, 20)
+MAKE_IMPORT_ENTRY(5,0, GetFileSizeEx, 8)
+MAKE_IMPORT_ENTRY(5,0, InitializeCriticalSectionAndSpinCount, 8)
+MAKE_IMPORT_ENTRY(4,0, FindFirstFileExW, 24)
+MAKE_IMPORT_ENTRY(4,0, IsProcessorFeaturePresent, 4)
+MAKE_IMPORT_ENTRY(4,0, CancelIo, 4)
+MAKE_IMPORT_ENTRY(3,51, FreeLibraryAndExitThread, 8)
+MAKE_IMPORT_ENTRY(3,51, IsDebuggerPresent, 0)
+MAKE_IMPORT_ENTRY(3,51, GetSystemTimeAsFileTime, 4)
+MAKE_IMPORT_ENTRY(3,50, EnumSystemLocalesW, 8)
+MAKE_IMPORT_ENTRY(3,50, GetVersionExA, 4)
+MAKE_IMPORT_ENTRY(3,50, GetVersionExW, 4)
+MAKE_IMPORT_ENTRY(3,50, GetEnvironmentStringsW, 0)
+MAKE_IMPORT_ENTRY(3,50, FreeEnvironmentStringsW, 4)
+MAKE_IMPORT_ENTRY(3,50, IsValidLocale, 8)
+MAKE_IMPORT_ENTRY(3,50, SetThreadAffinityMask, 8)
+MAKE_IMPORT_ENTRY(3,50, GetProcessAffinityMask, 12)
+MAKE_IMPORT_ENTRY(3,50, GetHandleInformation, 8)
+MAKE_IMPORT_ENTRY(3,50, SetHandleInformation, 12)
+
+COMMENT("Not needed (usually)")
+MAKE_IMPORT_ENTRY(5,1, HeapSetInformation, 16)
+MAKE_IMPORT_ENTRY(5,1, HeapQueryInformation, 20)
+MAKE_IMPORT_ENTRY(5,1, InterlockedFlushSList, 4)
+MAKE_IMPORT_ENTRY(5,1, InterlockedPopEntrySList, 4)
+MAKE_IMPORT_ENTRY(5,1, InterlockedPushEntrySList, 8)
+MAKE_IMPORT_ENTRY(5,1, QueryDepthSList, 4)
+MAKE_IMPORT_ENTRY(5,0, CreateTimerQueue, 0)
+MAKE_IMPORT_ENTRY(5,0, CreateTimerQueueTimer, 28)
+MAKE_IMPORT_ENTRY(5,0, DeleteTimerQueueTimer, 12)
+MAKE_IMPORT_ENTRY(5,0, VerSetConditionMask, 16)
+MAKE_IMPORT_ENTRY(3,51, PostQueuedCompletionStatus, 16)
+MAKE_IMPORT_ENTRY(3,51, CreateIoCompletionPort, 16)
+MAKE_IMPORT_ENTRY(3,51, GetQueuedCompletionStatus, 20)
+MAKE_IMPORT_ENTRY(3,50, GetLocaleInfoA, 16)
+MAKE_IMPORT_ENTRY(3,50, EnumSystemLocalesA, 8)
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-A.asm b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-A.asm
new file mode 100644
index 00000000..eb1449c3
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32-A.asm
@@ -0,0 +1,56 @@
+; $Id: vcc-fakes-kernel32-A.asm $
+;; @file
+; IPRT - Wrappers for kernel32 APIs missing in NT4 and earlier.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "vcc-fakes.mac"
+
+%define FAKE_MODULE_NAME kernel32
+
+BEGINDATA
+GLOBALNAME vcc100_kernel32_fakes_asm
+
+%ifdef VCC_FAKES_TARGET_VCC100
+ %include "vcc-fakes-kernel32-100.h"
+%elifdef VCC_FAKES_TARGET_VCC140
+ %include "vcc-fakes-kernel32-141.h"
+%elifdef VCC_FAKES_TARGET_VCC141
+ %include "vcc-fakes-kernel32-141.h"
+%elifdef VCC_FAKES_TARGET_VCC142
+ %include "vcc-fakes-kernel32-141.h"
+%else
+ %error "PORT ME!"
+%endif
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-kernel32.cpp b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32.cpp
new file mode 100644
index 00000000..697f22ca
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-kernel32.cpp
@@ -0,0 +1,891 @@
+/* $Id: vcc-fakes-kernel32.cpp $ */
+/** @file
+ * IPRT - Tricks to make the Visual C++ 2010 CRT work on NT4, W2K and XP.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cdefs.h>
+#include <iprt/types.h>
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+#ifdef DEBUG
+# include <stdio.h> /* _snprintf */
+#endif
+
+#ifndef RT_ARCH_X86
+# error "This code is X86 only"
+#endif
+
+#include <iprt/nt/nt-and-windows.h>
+
+#include "vcc-fakes.h"
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#ifndef HEAP_STANDARD
+# define HEAP_STANDARD 0
+#endif
+
+
+/** Declare a kernel32 API.
+ * @note We are not exporting them as that causes duplicate symbol troubles in
+ *       the OpenGL bits. */
+#define DECL_KERNEL32(a_Type) extern "C" a_Type WINAPI
+
+#if defined(WDK_NTDDI_VERSION) && defined(NTDDI_WIN10)
+# if WDK_NTDDI_VERSION >= NTDDI_WIN10 /* In Windows 10 SDK the 'Sequence' field has been renamed to 'CpuId'. */
+#  define SLIST_HEADER_SEQUENCE_NOW_CALLED_CPUID
+# endif
+#endif
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static volatile bool g_fInitialized = false;
+#define MAKE_IMPORT_ENTRY(a_uMajorVer, a_uMinorVer, a_Name, a_cb) DECLARE_FUNCTION_POINTER(a_Name, a_cb)
+#ifdef VCC_FAKES_TARGET_VCC100
+# include "vcc-fakes-kernel32-100.h"
+#elif defined(VCC_FAKES_TARGET_VCC140)
+# include "vcc-fakes-kernel32-141.h"
+#elif defined(VCC_FAKES_TARGET_VCC141)
+# include "vcc-fakes-kernel32-141.h"
+#elif defined(VCC_FAKES_TARGET_VCC142)
+# include "vcc-fakes-kernel32-141.h"
+#else
+# error "Port me!"
+#endif
+
+
+static BOOL FakeSetLastErrorFromNtStatus(NTSTATUS rcNt)
+{
+    DWORD dwErr;
+    switch (rcNt)
+    {
+        case STATUS_INVALID_PARAMETER:
+        case STATUS_INVALID_PARAMETER_1:
+        case STATUS_INVALID_PARAMETER_2:
+        case STATUS_INVALID_PARAMETER_3:
+        case STATUS_INVALID_PARAMETER_4:
+        case STATUS_INVALID_PARAMETER_5:
+        case STATUS_INVALID_PARAMETER_6:
+        case STATUS_INVALID_PARAMETER_7:
+        case STATUS_INVALID_PARAMETER_8:
+        case STATUS_INVALID_PARAMETER_9:
+        case STATUS_INVALID_PARAMETER_10:
+        case STATUS_INVALID_PARAMETER_11:
+        case STATUS_INVALID_PARAMETER_12:
+            dwErr = ERROR_INVALID_PARAMETER;
+            break;
+
+        case STATUS_INVALID_HANDLE:
+            dwErr = ERROR_INVALID_HANDLE;
+            break;
+
+        case STATUS_ACCESS_DENIED:
+            dwErr = ERROR_ACCESS_DENIED;
+            break;
+
+        default:
+            dwErr = ERROR_INVALID_PARAMETER;
+            break;
+    }
+    SetLastError(dwErr);
+    return FALSE;
+}
+
+
+
+DECL_KERNEL32(PVOID) Fake_DecodePointer(PVOID pvEncoded)
+{
+    return pvEncoded;
+}
+
+
+DECL_KERNEL32(PVOID) Fake_EncodePointer(PVOID pvNative)
+{
+    return pvNative;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_InitializeCriticalSectionAndSpinCount(LPCRITICAL_SECTION pCritSect, DWORD cSpin)
+{
+    RT_NOREF(cSpin);
+    InitializeCriticalSection(pCritSect);
+    return TRUE;
+}
+
+
+DECL_KERNEL32(HANDLE) Fake_CreateIoCompletionPort(HANDLE hFile, HANDLE hExistingCompletionPort, ULONG_PTR uCompletionKey,
+                                                  DWORD cConcurrentThreads)
+{
+    RT_NOREF(hFile, hExistingCompletionPort, uCompletionKey, cConcurrentThreads);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return NULL;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_GetQueuedCompletionStatus(HANDLE hCompletionPort, PDWORD_PTR pcbTransfered, PULONG_PTR puCompletionKey,
+                                                   LPOVERLAPPED *ppOverlapped, DWORD cMs)
+{
+    RT_NOREF(hCompletionPort, pcbTransfered, puCompletionKey, ppOverlapped, cMs);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_PostQueuedCompletionStatus(HANDLE hCompletionPort, DWORD cbTransfered, ULONG_PTR uCompletionKey,
+                                                    LPOVERLAPPED pOverlapped)
+{
+    RT_NOREF(hCompletionPort, cbTransfered, uCompletionKey, pOverlapped);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_HeapSetInformation(HANDLE hHeap, HEAP_INFORMATION_CLASS enmInfoClass, PVOID pvBuf, SIZE_T cbBuf)
+{
+    RT_NOREF(hHeap);
+    if (enmInfoClass == HeapCompatibilityInformation)
+    {
+        if (   cbBuf != sizeof(ULONG)
+            || !pvBuf
+            || *(PULONG)pvBuf == HEAP_STANDARD
+           )
+        {
+            SetLastError(ERROR_INVALID_PARAMETER);
+            return FALSE;
+        }
+        return TRUE;
+    }
+
+    SetLastError(ERROR_INVALID_PARAMETER);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_HeapQueryInformation(HANDLE hHeap, HEAP_INFORMATION_CLASS enmInfoClass,
+                                              PVOID pvBuf, SIZE_T cbBuf, PSIZE_T pcbRet)
+{
+    RT_NOREF(hHeap);
+    if (enmInfoClass == HeapCompatibilityInformation)
+    {
+        *pcbRet = sizeof(ULONG);
+        if (cbBuf < sizeof(ULONG) || !pvBuf)
+        {
+            SetLastError(ERROR_INSUFFICIENT_BUFFER);
+            return FALSE;
+        }
+        *(PULONG)pvBuf = HEAP_STANDARD;
+        return TRUE;
+    }
+
+    SetLastError(ERROR_INVALID_PARAMETER);
+    return FALSE;
+}
+
+
+/* These are used by INTEL\mt_obj\Timer.obj: */
+
+DECL_KERNEL32(HANDLE) Fake_CreateTimerQueue(void)
+{
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return NULL;
+}
+
+DECL_KERNEL32(BOOL) Fake_CreateTimerQueueTimer(PHANDLE phTimer, HANDLE hTimerQueue, WAITORTIMERCALLBACK pfnCallback, PVOID pvUser,
+                                               DWORD msDueTime, DWORD msPeriod, ULONG fFlags)
+{
+    NOREF(phTimer); NOREF(hTimerQueue); NOREF(pfnCallback); NOREF(pvUser); NOREF(msDueTime); NOREF(msPeriod); NOREF(fFlags);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+DECL_KERNEL32(BOOL) Fake_DeleteTimerQueueTimer(HANDLE hTimerQueue, HANDLE hTimer, HANDLE hEvtCompletion)
+{
+    NOREF(hTimerQueue); NOREF(hTimer); NOREF(hEvtCompletion);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+/* This is used by several APIs. */
+
+DECL_KERNEL32(VOID) Fake_InitializeSListHead(PSLIST_HEADER pHead)
+{
+    pHead->Alignment = 0;
+}
+
+
+DECL_KERNEL32(PSLIST_ENTRY) Fake_InterlockedFlushSList(PSLIST_HEADER pHead)
+{
+    PSLIST_ENTRY pRet = NULL;
+    if (pHead->Next.Next)
+    {
+        for (;;)
+        {
+            SLIST_HEADER OldHead = *pHead;
+            SLIST_HEADER NewHead;
+            NewHead.Alignment = 0;
+#ifdef SLIST_HEADER_SEQUENCE_NOW_CALLED_CPUID
+            NewHead.CpuId  = OldHead.CpuId + 1;
+#else
+            NewHead.Sequence  = OldHead.Sequence + 1;
+#endif
+            if (ASMAtomicCmpXchgU64(&pHead->Alignment, NewHead.Alignment, OldHead.Alignment))
+            {
+                pRet = OldHead.Next.Next;
+                break;
+            }
+        }
+    }
+    return pRet;
+}
+
+DECL_KERNEL32(PSLIST_ENTRY) Fake_InterlockedPopEntrySList(PSLIST_HEADER pHead)
+{
+    PSLIST_ENTRY pRet = NULL;
+    for (;;)
+    {
+        SLIST_HEADER OldHead = *pHead;
+        pRet = OldHead.Next.Next;
+        if (pRet)
+        {
+            SLIST_HEADER NewHead;
+            __try
+            {
+                NewHead.Next.Next = pRet->Next;
+            }
+            __except(EXCEPTION_EXECUTE_HANDLER)
+            {
+                continue;
+            }
+            NewHead.Depth     = OldHead.Depth - 1;
+#ifdef SLIST_HEADER_SEQUENCE_NOW_CALLED_CPUID
+            NewHead.CpuId  = OldHead.CpuId + 1;
+#else
+            NewHead.Sequence  = OldHead.Sequence + 1;
+#endif
+            if (ASMAtomicCmpXchgU64(&pHead->Alignment, NewHead.Alignment, OldHead.Alignment))
+                break;
+        }
+        else
+            break;
+    }
+    return pRet;
+}
+
+DECL_KERNEL32(PSLIST_ENTRY) Fake_InterlockedPushEntrySList(PSLIST_HEADER pHead, PSLIST_ENTRY pEntry)
+{
+    PSLIST_ENTRY pRet = NULL;
+    for (;;)
+    {
+        SLIST_HEADER OldHead = *pHead;
+        pRet = OldHead.Next.Next;
+        pEntry->Next = pRet;
+        SLIST_HEADER NewHead;
+        NewHead.Next.Next = pEntry;
+        NewHead.Depth     = OldHead.Depth + 1;
+#ifdef SLIST_HEADER_SEQUENCE_NOW_CALLED_CPUID
+        NewHead.CpuId  = OldHead.CpuId + 1;
+#else
+        NewHead.Sequence  = OldHead.Sequence + 1;
+#endif
+        if (ASMAtomicCmpXchgU64(&pHead->Alignment, NewHead.Alignment, OldHead.Alignment))
+            break;
+    }
+    return pRet;
+}
+
+DECL_KERNEL32(WORD) Fake_QueryDepthSList(PSLIST_HEADER pHead)
+{
+    return pHead->Depth;
+}
+
+
+/* curl drags these in: */
+DECL_KERNEL32(BOOL) Fake_VerifyVersionInfoA(LPOSVERSIONINFOEXA pInfo, DWORD fTypeMask, DWORDLONG fConditionMask)
+{
+    OSVERSIONINFOEXA VerInfo;
+    RT_ZERO(VerInfo);
+    VerInfo.dwOSVersionInfoSize = sizeof(VerInfo);
+    if (!GetVersionExA((OSVERSIONINFO *)&VerInfo))
+    {
+        RT_ZERO(VerInfo);
+        VerInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+        BOOL fRet = GetVersionExA((OSVERSIONINFO *)&VerInfo);
+        if (fRet)
+        { /* likely */ }
+        else
+        {
+            MY_ASSERT(false, "VerifyVersionInfoA: #1");
+            return FALSE;
+        }
+    }
+
+    BOOL fRet = TRUE;
+    for (unsigned i = 0; i < 8 && fRet; i++)
+        if (fTypeMask & RT_BIT_32(i))
+        {
+            uint32_t uLeft, uRight;
+            switch (RT_BIT_32(i))
+            {
+#define MY_CASE(a_Num, a_Member) case a_Num: uLeft = VerInfo.a_Member; uRight = pInfo->a_Member; break
+                MY_CASE(VER_MINORVERSION,       dwMinorVersion);
+                MY_CASE(VER_MAJORVERSION,       dwMajorVersion);
+                MY_CASE(VER_BUILDNUMBER,        dwBuildNumber);
+                MY_CASE(VER_PLATFORMID,         dwPlatformId);
+                MY_CASE(VER_SERVICEPACKMINOR,   wServicePackMinor);
+                MY_CASE(VER_SERVICEPACKMAJOR,   wServicePackMinor);
+                MY_CASE(VER_SUITENAME,          wSuiteMask);
+                MY_CASE(VER_PRODUCT_TYPE,       wProductType);
+#undef  MY_CASE
+                default: uLeft = uRight = 0; MY_ASSERT(false, "VerifyVersionInfoA: #2");
+            }
+            switch ((uint8_t)(fConditionMask >> (i*8)))
+            {
+                case VER_EQUAL:             fRet = uLeft == uRight; break;
+                case VER_GREATER:           fRet = uLeft >  uRight; break;
+                case VER_GREATER_EQUAL:     fRet = uLeft >= uRight; break;
+                case VER_LESS:              fRet = uLeft <  uRight; break;
+                case VER_LESS_EQUAL:        fRet = uLeft <= uRight; break;
+                case VER_AND:               fRet = (uLeft & uRight) == uRight; break;
+                case VER_OR:                fRet = (uLeft & uRight) != 0; break;
+                default:                    fRet = FALSE; MY_ASSERT(false, "VerifyVersionInfoA: #3"); break;
+            }
+        }
+
+    return fRet;
+}
+
+
+DECL_KERNEL32(ULONGLONG) Fake_VerSetConditionMask(ULONGLONG fConditionMask, DWORD fTypeMask, BYTE bOperator)
+{
+    for (unsigned i = 0; i < 8; i++)
+        if (fTypeMask & RT_BIT_32(i))
+        {
+            uint64_t fMask  = UINT64_C(0xff) << (i*8);
+            fConditionMask &= ~fMask;
+            fConditionMask |= (uint64_t)bOperator << (i*8);
+
+        }
+    return fConditionMask;
+}
+
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 5.0 (windows 2000) */
+DECL_KERNEL32(BOOL) Fake_GetModuleHandleExW(DWORD dwFlags, LPCWSTR pwszModuleName, HMODULE *phModule)
+{
+    HMODULE hmod;
+    if (dwFlags & GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS)
+    {
+        /** @todo search the loader list. */
+        SetLastError(ERROR_NOT_SUPPORTED);
+        return FALSE;
+    }
+    else
+    {
+        hmod = GetModuleHandleW(pwszModuleName);
+        if (!hmod)
+            return FALSE;
+    }
+
+    /*
+     * Get references to the module.
+     */
+    if (   !(dwFlags & (GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT | GET_MODULE_HANDLE_EX_FLAG_PIN))
+        && GetModuleHandleW(NULL) != hmod)
+    {
+        WCHAR wszModule[MAX_PATH];
+        if (GetModuleFileNameW(hmod, wszModule, RT_ELEMENTS(wszModule)) > 0)
+        {
+            if (dwFlags & GET_MODULE_HANDLE_EX_FLAG_PIN)
+            {
+                uint32_t cRefs = 32;
+                while (cRefs-- > 0)
+                    LoadLibraryW(wszModule);
+            }
+            else if (!LoadLibraryW(wszModule))
+                return FALSE;
+        }
+    }
+
+    *phModule = hmod;
+    return TRUE;
+}
+#endif /* VCC_FAKES_TARGET >= 141 */
+
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 5.0 (windows 2000) */
+DECL_KERNEL32(BOOL) Fake_SetFilePointerEx(HANDLE hFile, LARGE_INTEGER offDistanceToMove,
+                                          PLARGE_INTEGER pNewFilePointer, DWORD dwMoveMethod)
+{
+    NTSTATUS                    rcNt;
+    IO_STATUS_BLOCK             Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+
+    FILE_POSITION_INFORMATION   PosInfo;
+    switch (dwMoveMethod)
+    {
+        case FILE_BEGIN:
+            PosInfo.CurrentByteOffset = offDistanceToMove;
+            break;
+
+        case FILE_CURRENT:
+            PosInfo.CurrentByteOffset.QuadPart = INT64_MAX;
+            rcNt = NtQueryInformationFile(hFile, &Ios, &PosInfo, sizeof(PosInfo), FilePositionInformation);
+            if (NT_SUCCESS(rcNt))
+            {
+                PosInfo.CurrentByteOffset.QuadPart += offDistanceToMove.QuadPart;
+                break;
+            }
+            return FakeSetLastErrorFromNtStatus(rcNt);
+
+        case FILE_END:
+        {
+            FILE_STANDARD_INFO StdInfo = {{0}};
+            rcNt = NtQueryInformationFile(hFile, &Ios, &StdInfo, sizeof(StdInfo), FileStandardInformation);
+            if (NT_SUCCESS(rcNt))
+            {
+                PosInfo.CurrentByteOffset.QuadPart = offDistanceToMove.QuadPart + StdInfo.EndOfFile.QuadPart;
+                break;
+            }
+            return FakeSetLastErrorFromNtStatus(rcNt);
+        }
+
+        default:
+            SetLastError(ERROR_INVALID_PARAMETER);
+            return FALSE;
+    }
+
+    rcNt = NtSetInformationFile(hFile, &Ios, &PosInfo, sizeof(PosInfo), FilePositionInformation);
+    if (NT_SUCCESS(rcNt))
+    {
+        if (pNewFilePointer)
+            *pNewFilePointer = PosInfo.CurrentByteOffset;
+        return TRUE;
+    }
+    return FakeSetLastErrorFromNtStatus(rcNt);
+}
+#endif /* VCC_FAKES_TARGET >= 140 */
+
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 5.0 (windows 2000) */
+DECL_KERNEL32(BOOL) Fake_GetFileSizeEx(HANDLE hFile, PLARGE_INTEGER pcbFile)
+{
+    IO_STATUS_BLOCK    Ios     = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+    FILE_STANDARD_INFO StdInfo = {{0}};
+    NTSTATUS rcNt = NtQueryInformationFile(hFile, &Ios, &StdInfo, sizeof(StdInfo), FileStandardInformation);
+    if (NT_SUCCESS(rcNt))
+    {
+        *pcbFile = StdInfo.EndOfFile;
+        return TRUE;
+    }
+    return FakeSetLastErrorFromNtStatus(rcNt);
+}
+#endif /* VCC_FAKES_TARGET >= 140 */
+
+
+
+
+/*
+ * NT 3.51 stuff.
+ */
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 4.0 */
+DECL_KERNEL32(HANDLE) Fake_FindFirstFileExW(LPCWSTR pwszFileName, FINDEX_INFO_LEVELS enmInfoLevel, LPVOID pvFindFileData,
+                                            FINDEX_SEARCH_OPS enmSearchOp, LPVOID pvSearchFilter, DWORD dwAdditionalFlags)
+{
+    // STL:                FindFirstFileExW(, FindExInfoBasic,    , FindExSearchNameMatch, NULL, 0);
+    // CRT/_findfile:      FindFirstFileExW(, FindExInfoStandard, , FindExSearchNameMatch, NULL, 0);
+    // CRT/argv_wildcards: FindFirstFileExW(, FindExInfoStandard, , FindExSearchNameMatch, NULL, 0);
+    MY_ASSERT_STMT_RETURN(dwAdditionalFlags == 0, SetLastError(ERROR_INVALID_PARAMETER), INVALID_HANDLE_VALUE);
+    MY_ASSERT_STMT_RETURN(pvSearchFilter == NULL, SetLastError(ERROR_INVALID_PARAMETER), INVALID_HANDLE_VALUE);
+    MY_ASSERT_STMT_RETURN(enmSearchOp == FindExSearchNameMatch, SetLastError(ERROR_INVALID_PARAMETER), INVALID_HANDLE_VALUE);
+    MY_ASSERT_STMT_RETURN(enmInfoLevel == FindExInfoStandard || enmInfoLevel == FindExInfoBasic,
+                          SetLastError(ERROR_INVALID_PARAMETER), INVALID_HANDLE_VALUE);
+
+    return FindFirstFileW(pwszFileName, (WIN32_FIND_DATAW *)pvFindFileData);
+}
+#endif /* VCC_FAKES_TARGET >= 140 */
+
+
+DECL_KERNEL32(BOOL) Fake_IsProcessorFeaturePresent(DWORD enmProcessorFeature)
+{
+    /* Could make more of an effort here... */
+    RT_NOREF(enmProcessorFeature);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_CancelIo(HANDLE hHandle)
+{
+    /* All NT versions the NTDLL API this corresponds to. */
+    RESOLVE_NTDLL_API(NtCancelIoFile);
+    if (pfnNtCancelIoFile)
+    {
+        IO_STATUS_BLOCK Ios = RTNT_IO_STATUS_BLOCK_INITIALIZER;
+        NTSTATUS rcNt = pfnNtCancelIoFile(hHandle, &Ios);
+        if (RT_SUCCESS(rcNt))
+            return TRUE;
+        if (rcNt == STATUS_INVALID_HANDLE)
+            SetLastError(ERROR_INVALID_HANDLE);
+        else
+            SetLastError(ERROR_INVALID_FUNCTION);
+    }
+    else
+        SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+
+/*
+ * NT 3.50 stuff.
+ */
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 3.51 */
+DECL_KERNEL32(VOID) Fake_FreeLibraryAndExitThread(HMODULE hLibModule, DWORD dwExitCode)
+{
+    if (hLibModule)
+        FreeModule(hLibModule);
+    ExitThread(dwExitCode);
+}
+#endif /* VCC_FAKES_TARGET >= 140 */
+
+
+DECL_KERNEL32(BOOL) Fake_IsDebuggerPresent(VOID)
+{
+    /* Fallback: */
+    return FALSE;
+}
+
+
+DECL_KERNEL32(VOID) Fake_GetSystemTimeAsFileTime(LPFILETIME pTime)
+{
+    DWORD dwVersion = GetVersion();
+    if (   (dwVersion & 0xff) > 3
+        || (   (dwVersion & 0xff) == 3
+            && ((dwVersion >> 8) & 0xff) >= 50) )
+    {
+        PKUSER_SHARED_DATA pUsd = (PKUSER_SHARED_DATA)MM_SHARED_USER_DATA_VA;
+
+        /* use interrupt time */
+        LARGE_INTEGER Time;
+        do
+        {
+            Time.HighPart = pUsd->SystemTime.High1Time;
+            Time.LowPart  = pUsd->SystemTime.LowPart;
+        } while (pUsd->SystemTime.High2Time != Time.HighPart);
+
+        pTime->dwHighDateTime = Time.HighPart;
+        pTime->dwLowDateTime  = Time.LowPart;
+    }
+    else
+    {
+        /* NT 3.1 didn't have a KUSER_SHARED_DATA nor a GetSystemTimeAsFileTime export. */
+        SYSTEMTIME SystemTime;
+        GetSystemTime(&SystemTime);
+        BOOL fRet = SystemTimeToFileTime(&SystemTime, pTime);
+        if (fRet)
+        { /* likely */ }
+        else
+        {
+            MY_ASSERT(false, "GetSystemTimeAsFileTime: #2");
+            pTime->dwHighDateTime = 0;
+            pTime->dwLowDateTime  = 0;
+        }
+    }
+}
+
+
+/*
+ * NT 3.1 stuff.
+ */
+
+DECL_KERNEL32(BOOL) Fake_GetVersionExA(LPOSVERSIONINFOA pInfo)
+{
+    DWORD dwVersion = GetVersion();
+
+    /* Common fields: */
+    pInfo->dwMajorVersion = dwVersion & 0xff;
+    pInfo->dwMinorVersion = (dwVersion >> 8) & 0xff;
+    if (!(dwVersion & RT_BIT_32(31)))
+        pInfo->dwBuildNumber = dwVersion >> 16;
+    else
+        pInfo->dwBuildNumber = 511;
+    pInfo->dwPlatformId = VER_PLATFORM_WIN32_NT;
+/** @todo get CSD from registry. */
+    pInfo->szCSDVersion[0] = '\0';
+
+    /* OSVERSIONINFOEX fields: */
+    if (pInfo->dwOSVersionInfoSize > sizeof((*pInfo)))
+    {
+        LPOSVERSIONINFOEXA pInfoEx = (LPOSVERSIONINFOEXA)pInfo;
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXA, wServicePackMinor))
+        {
+            pInfoEx->wServicePackMajor = 0;
+            pInfoEx->wServicePackMinor = 0;
+        }
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXA, wSuiteMask))
+            pInfoEx->wSuiteMask = 0;
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXA, wProductType))
+            pInfoEx->wProductType = VER_NT_WORKSTATION;
+        if (pInfoEx->wReserved > RT_UOFFSETOF(OSVERSIONINFOEXA, wProductType))
+            pInfoEx->wReserved = 0;
+    }
+
+    return TRUE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_GetVersionExW(LPOSVERSIONINFOW pInfo)
+{
+    DWORD dwVersion = GetVersion();
+
+    /* Common fields: */
+    pInfo->dwMajorVersion = dwVersion & 0xff;
+    pInfo->dwMinorVersion = (dwVersion >> 8) & 0xff;
+    if (!(dwVersion & RT_BIT_32(31)))
+        pInfo->dwBuildNumber = dwVersion >> 16;
+    else
+        pInfo->dwBuildNumber = 511;
+    pInfo->dwPlatformId = VER_PLATFORM_WIN32_NT;
+/** @todo get CSD from registry. */
+    pInfo->szCSDVersion[0] = '\0';
+
+    /* OSVERSIONINFOEX fields: */
+    if (pInfo->dwOSVersionInfoSize > sizeof((*pInfo)))
+    {
+        LPOSVERSIONINFOEXW pInfoEx = (LPOSVERSIONINFOEXW)pInfo;
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXW, wServicePackMinor))
+        {
+            pInfoEx->wServicePackMajor = 0;
+            pInfoEx->wServicePackMinor = 0;
+        }
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXW, wSuiteMask))
+            pInfoEx->wSuiteMask = 0;
+        if (pInfoEx->dwOSVersionInfoSize > RT_UOFFSETOF(OSVERSIONINFOEXW, wProductType))
+            pInfoEx->wProductType = VER_NT_WORKSTATION;
+        if (pInfoEx->wReserved > RT_UOFFSETOF(OSVERSIONINFOEXW, wProductType))
+            pInfoEx->wReserved = 0;
+    }
+
+    return TRUE;
+}
+
+
+DECL_KERNEL32(LPWCH) Fake_GetEnvironmentStringsW(void)
+{
+    /*
+     * Environment is ANSI in NT 3.1. We should only be here for NT 3.1.
+     * For now, don't try do a perfect job converting it, just do it.
+     */
+    char    *pszzEnv = (char *)RTNtCurrentPeb()->ProcessParameters->Environment;
+    size_t   offEnv  = 0;
+    while (pszzEnv[offEnv] != '\0')
+    {
+        size_t cchLen = strlen(&pszzEnv[offEnv]);
+        offEnv += cchLen + 1;
+    }
+    size_t const cchEnv = offEnv + 1;
+
+    PRTUTF16 pwszzEnv = (PRTUTF16)HeapAlloc(GetProcessHeap(), 0, cchEnv * sizeof(RTUTF16));
+    if (!pwszzEnv)
+        return NULL;
+    for (offEnv = 0; offEnv < cchEnv; offEnv++)
+    {
+        unsigned char ch = pwszzEnv[offEnv];
+        if (!(ch & 0x80))
+            pwszzEnv[offEnv] = ch;
+        else
+            pwszzEnv[offEnv] = '_';
+    }
+    return pwszzEnv;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_FreeEnvironmentStringsW(LPWCH pwszzEnv)
+{
+    if (pwszzEnv)
+        HeapFree(GetProcessHeap(), 0, pwszzEnv);
+    return TRUE;
+}
+
+
+DECL_KERNEL32(int) Fake_GetLocaleInfoA(LCID idLocale, LCTYPE enmType, LPSTR pData, int cchData)
+{
+    NOREF(idLocale); NOREF(enmType); NOREF(pData); NOREF(cchData);
+    //MY_ASSERT(false, "GetLocaleInfoA: idLocale=%#x enmType=%#x cchData=%#x", idLocale, enmType, cchData);
+    MY_ASSERT(false, "GetLocaleInfoA");
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return 0;
+}
+
+
+#if VCC_FAKES_TARGET >= 140
+/** @since 3.51 */
+DECL_KERNEL32(BOOL) Fake_EnumSystemLocalesW(LOCALE_ENUMPROCW pfnLocaleEnum, DWORD dwFlags)
+{
+    RT_NOREF(pfnLocaleEnum, dwFlags);
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+#endif /* VCC_FAKES_TARGET >= 140 */
+
+
+DECL_KERNEL32(BOOL) Fake_EnumSystemLocalesA(LOCALE_ENUMPROCA pfnCallback, DWORD fFlags)
+{
+    NOREF(pfnCallback); NOREF(fFlags);
+    //MY_ASSERT(false, "EnumSystemLocalesA: pfnCallback=%p fFlags=%#x", pfnCallback, fFlags);
+    MY_ASSERT(false, "EnumSystemLocalesA");
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_IsValidLocale(LCID idLocale, DWORD fFlags)
+{
+    NOREF(idLocale); NOREF(fFlags);
+    //MY_ASSERT(false, "IsValidLocale: idLocale fFlags=%#x", idLocale, fFlags);
+    MY_ASSERT(false, "IsValidLocale");
+    SetLastError(ERROR_NOT_SUPPORTED);
+    return FALSE;
+}
+
+
+DECL_KERNEL32(DWORD_PTR) Fake_SetThreadAffinityMask(HANDLE hThread, DWORD_PTR fAffinityMask)
+{
+    SYSTEM_INFO SysInfo;
+    GetSystemInfo(&SysInfo);
+    //MY_ASSERT(false, "SetThreadAffinityMask: hThread=%p fAffinityMask=%p SysInfo.dwActiveProcessorMask=%p",
+    //          hThread, fAffinityMask, SysInfo.dwActiveProcessorMask);
+    MY_ASSERT(false, "SetThreadAffinityMask");
+    if (   SysInfo.dwActiveProcessorMask == fAffinityMask
+        || fAffinityMask                 == ~(DWORD_PTR)0)
+        return fAffinityMask;
+
+    SetLastError(ERROR_NOT_SUPPORTED);
+    RT_NOREF(hThread);
+    return 0;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_GetProcessAffinityMask(HANDLE hProcess, PDWORD_PTR pfProcessAffinityMask, PDWORD_PTR pfSystemAffinityMask)
+{
+    SYSTEM_INFO SysInfo;
+    GetSystemInfo(&SysInfo);
+    //MY_ASSERT(false, "GetProcessAffinityMask: SysInfo.dwActiveProcessorMask=%p", SysInfo.dwActiveProcessorMask);
+    MY_ASSERT(false, "GetProcessAffinityMask");
+    if (pfProcessAffinityMask)
+        *pfProcessAffinityMask = SysInfo.dwActiveProcessorMask;
+    if (pfSystemAffinityMask)
+        *pfSystemAffinityMask  = SysInfo.dwActiveProcessorMask;
+    RT_NOREF(hProcess);
+    return TRUE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_GetHandleInformation(HANDLE hObject, DWORD *pfFlags)
+{
+    OBJECT_HANDLE_FLAG_INFORMATION  Info  = { 0, 0 };
+    DWORD                           cbRet = sizeof(Info);
+    NTSTATUS rcNt = NtQueryObject(hObject, ObjectHandleFlagInformation, &Info, sizeof(Info), &cbRet);
+    if (NT_SUCCESS(rcNt))
+    {
+        *pfFlags = (Info.Inherit          ? HANDLE_FLAG_INHERIT : 0)
+                 | (Info.ProtectFromClose ? HANDLE_FLAG_PROTECT_FROM_CLOSE : 0);
+        return TRUE;
+    }
+    *pfFlags = 0;
+    //MY_ASSERT(rcNt == STATUS_INVALID_HANDLE, "rcNt=%#x", rcNt);
+    MY_ASSERT(rcNt == STATUS_INVALID_HANDLE || rcNt == STATUS_INVALID_INFO_CLASS, "GetHandleInformation");
+    SetLastError(rcNt == STATUS_INVALID_HANDLE ? ERROR_INVALID_HANDLE : ERROR_INVALID_FUNCTION); /* see also process-win.cpp */
+    return FALSE;
+}
+
+
+DECL_KERNEL32(BOOL) Fake_SetHandleInformation(HANDLE hObject, DWORD fMask, DWORD fFlags)
+{
+    NOREF(hObject); NOREF(fMask); NOREF(fFlags);
+    SetLastError(ERROR_INVALID_FUNCTION);
+    return FALSE;
+}
+
+
+
+/**
+ * Resolves all the APIs ones and for all, updating the fake IAT entries.
+ */
+DECLASM(void) FakeResolve_kernel32(void)
+{
+    CURRENT_VERSION_VARIABLE();
+
+    HMODULE hmod = GetModuleHandleW(L"kernel32");
+    MY_ASSERT(hmod != NULL, "kernel32");
+
+#undef MAKE_IMPORT_ENTRY
+#define MAKE_IMPORT_ENTRY(a_uMajorVer, a_uMinorVer, a_Name, a_cb) RESOLVE_IMPORT(a_uMajorVer, a_uMinorVer, a_Name, a_cb)
+#ifdef VCC_FAKES_TARGET_VCC100
+# include "vcc-fakes-kernel32-100.h"
+#elif defined(VCC_FAKES_TARGET_VCC140)
+# include "vcc-fakes-kernel32-141.h"
+#elif defined(VCC_FAKES_TARGET_VCC141)
+# include "vcc-fakes-kernel32-141.h"
+#elif defined(VCC_FAKES_TARGET_VCC142)
+# include "vcc-fakes-kernel32-141.h"
+#else
+# error "Port me!"
+#endif
+
+    g_fInitialized = true;
+}
+
+
+/* Dummy to force dragging in this object in the link, so the linker
+   won't accidentally use the symbols from kernel32. */
+extern "C" int vcc100_kernel32_fakes_cpp(void)
+{
+    return 42;
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-msvcrt.cpp b/src/VBox/Runtime/r3/win/vcc-fakes-msvcrt.cpp
new file mode 100644
index 00000000..9aaf2d4d
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-msvcrt.cpp
@@ -0,0 +1,93 @@
+/* $Id: vcc-fakes-msvcrt.cpp $ */
+/** @file
+ * IPRT - Tricks to make the Visual C++ 2010 CRT work on NT4, W2K and XP.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/assert.h>
+#include <stdlib.h>
+
+
+#ifndef RT_ARCH_X86
+# error "This code is X86 only"
+#endif
+
+
+
+/* This one is static in libcmt, fortunately no rocket science.  */
+extern "C" void __cdecl my_initterm(PFNRT *papfnStart, PFNRT *papfnEnd)
+{
+    for (; (uintptr_t)papfnStart < (uintptr_t)papfnEnd; papfnStart++)
+        if (*papfnStart)
+            (*papfnStart)();
+}
+
+extern "C" PFNRT __cdecl my_dllonexit(PFNRT pfnToAdd, PFNRT **ppapfnStart, PFNRT **ppapfnEnd)
+{
+    /* This is _very_ crude, but it'll probably do for our purposes... */
+    size_t cItems = *ppapfnEnd - *ppapfnStart;
+    *ppapfnStart = (PFNRT *)realloc(*ppapfnStart, (cItems + 1) * sizeof(**ppapfnStart));
+    (*ppapfnStart)[cItems] = pfnToAdd;
+    *ppapfnEnd = &(*ppapfnStart)[cItems + 1];
+    return pfnToAdd;
+}
+
+extern "C" int _newmode;
+extern "C" int __cdecl __setargv(void);
+extern "C" int __cdecl _setargv(void);
+
+extern "C" int __cdecl my_getmainargs(int *pcArgs, char ***ppapszArgs, char ***ppapszEnv, int fDoWildcardExp, int *pfNewMode)
+{
+    _newmode = *pfNewMode;
+
+    Assert(!fDoWildcardExp);
+    int rc = _setargv();
+    if (rc >= 0)
+    {
+        *pcArgs     = __argc;
+        *ppapszArgs = __argv;
+        *ppapszEnv  = _environ;
+    }
+    return rc;
+}
+
+extern "C" void __cdecl my_setusermatherr(PFNRT pfnIgnore)
+{
+    RT_NOREF(pfnIgnore);
+    /* pure stub. */
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-ntdll-A.asm b/src/VBox/Runtime/r3/win/vcc-fakes-ntdll-A.asm
new file mode 100644
index 00000000..4eb482b2
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-ntdll-A.asm
@@ -0,0 +1,57 @@
+; $Id: vcc-fakes-ntdll-A.asm $
+;; @file
+; IPRT - Wrappers for ntdll APIs misisng NT4.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+%include "iprt/asmdefs.mac"
+
+%ifndef RT_ARCH_X86
+ %error "This is x86 only code.
+%endif
+
+
+%macro MAKE_IMPORT_ENTRY 2
+extern _ %+ %1 %+ @ %+ %2
+global __imp__ %+ %1 %+ @ %+ %2
+__imp__ %+ %1 %+ @ %+ %2:
+    dd _ %+ %1 %+ @ %+ %2
+
+%endmacro
+
+
+BEGINDATA
+GLOBALNAME vcc100_ntdll_fakes_asm
+
+MAKE_IMPORT_ENTRY RtlGetLastWin32Error, 0
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-ntdll.cpp b/src/VBox/Runtime/r3/win/vcc-fakes-ntdll.cpp
new file mode 100644
index 00000000..9aa5dd01
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-ntdll.cpp
@@ -0,0 +1,84 @@
+/* $Id: vcc-fakes-ntdll.cpp $ */
+/** @file
+ * IPRT - Tricks to make the Visual C++ 2010 CRT work on NT4, W2K and XP - NTDLL.DLL.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cdefs.h>
+#include <iprt/types.h>
+
+#ifndef RT_ARCH_X86
+# error "This code is X86 only"
+#endif
+
+#include <iprt/win/windows.h>
+
+
+
+/** Dynamically resolves an kernel32 API.   */
+#define RESOLVE_ME(ApiNm) \
+    static bool volatile    s_fInitialized = false; \
+    static decltype(ApiNm) *s_pfnApi = NULL; \
+    decltype(ApiNm)        *pfnApi; \
+    if (s_fInitialized) \
+        pfnApi = s_pfnApi; \
+    else \
+    { \
+        pfnApi = (decltype(pfnApi))GetProcAddress(GetModuleHandleW(L"ntdll.dll"), #ApiNm); \
+        s_pfnApi = pfnApi; \
+        s_fInitialized = true; \
+    } do {} while (0) \
+
+
+extern "C"
+__declspec(dllexport)
+ULONG WINAPI RtlGetLastWin32Error(VOID)
+{
+    RESOLVE_ME(RtlGetLastWin32Error);
+    if (pfnApi)
+        return pfnApi();
+    return GetLastError();
+}
+
+
+/* Dummy to force dragging in this object in the link, so the linker
+   won't accidentally use the symbols from kernel32. */
+extern "C" int vcc100_ntdll_fakes_cpp(void)
+{
+    return 42;
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-shell32-A.asm b/src/VBox/Runtime/r3/win/vcc-fakes-shell32-A.asm
new file mode 100644
index 00000000..ddf7491b
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-shell32-A.asm
@@ -0,0 +1,59 @@
+; $Id: vcc-fakes-shell32-A.asm $
+;; @file
+; IPRT - Wrappers for shell32 APIs missing in NT 4 and earlier.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "iprt/asmdefs.mac"
+
+%ifndef RT_ARCH_X86
+ %error "This is x86 only code.
+%endif
+
+
+%macro MAKE_IMPORT_ENTRY 2
+extern _ %+ %1 %+ @ %+ %2
+global __imp__ %+ %1 %+ @ %+ %2
+__imp__ %+ %1 %+ @ %+ %2:
+    dd _ %+ %1 %+ @ %+ %2
+
+%endmacro
+
+
+BEGINDATA
+GLOBALNAME vcc100_shell32_fakes_asm
+
+; NT 3.1
+MAKE_IMPORT_ENTRY CommandLineToArgvW, 8
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-shell32.cpp b/src/VBox/Runtime/r3/win/vcc-fakes-shell32.cpp
new file mode 100644
index 00000000..bd82befa
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-shell32.cpp
@@ -0,0 +1,103 @@
+/* $Id: vcc-fakes-shell32.cpp $ */
+/** @file
+ * IPRT - Tricks to make the Visual C++ 2010 CRT work on NT4, W2K and XP.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define RT_NO_STRICT /* Minimal deps so that it works on NT 3.51 too. */
+#include <iprt/types.h>
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+#ifndef RT_ARCH_X86
+# error "This code is X86 only"
+#endif
+
+#define CommandLineToArgvW                      Ignore_CommandLineToArgvW
+
+#include <iprt/nt/nt-and-windows.h>
+
+#undef CommandLineToArgvW
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+/** Dynamically resolves an kernel32 API.   */
+#define RESOLVE_ME(ApiNm) \
+    static decltype(ShellExecuteW) * volatile s_pfnInitialized = NULL; \
+    static decltype(ApiNm) *s_pfnApi = NULL; \
+    decltype(ApiNm)        *pfnApi; \
+    if (s_pfnInitialized) \
+        pfnApi = s_pfnApi; \
+    else \
+    { \
+        pfnApi = (decltype(pfnApi))GetProcAddress(GetModuleHandleW(L"shell32"), #ApiNm); \
+        s_pfnApi = pfnApi; \
+        s_pfnInitialized = ShellExecuteW; /* ensures shell32 is loaded */ \
+    } do {} while (0)
+
+
+/** Declare a shell32 API.
+ * @note We are not exporting them as that causes duplicate symbol troubles in
+ *       the OpenGL bits. */
+#define DECL_SHELL32(a_Type) extern "C" a_Type WINAPI
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+
+
+DECL_SHELL32(LPWSTR *) CommandLineToArgvW(LPCWSTR pwszCmdLine, int *pcArgs)
+{
+    RESOLVE_ME(CommandLineToArgvW);
+    if (pfnApi)
+        return pfnApi(pwszCmdLine, pcArgs);
+
+    *pcArgs = 0;
+    return NULL;
+}
+
+
+/* Dummy to force dragging in this object in the link, so the linker
+   won't accidentally use the symbols from shell32. */
+extern "C" int vcc100_shell32_fakes_cpp(void)
+{
+    return 42;
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32-A.asm b/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32-A.asm
new file mode 100644
index 00000000..2158917a
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32-A.asm
@@ -0,0 +1,58 @@
+; $Id: vcc-fakes-ws2_32-A.asm $
+;; @file
+; IPRT - Wrappers for ws2_32 APIs misisng NT4.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+%include "iprt/asmdefs.mac"
+
+%ifndef RT_ARCH_X86
+ %error "This is x86 only code.
+%endif
+
+
+%macro MAKE_IMPORT_ENTRY 2
+extern _ %+ %1 %+ @ %+ %2
+global __imp__ %+ %1 %+ @ %+ %2
+__imp__ %+ %1 %+ @ %+ %2:
+    dd _ %+ %1 %+ @ %+ %2
+
+%endmacro
+
+
+BEGINDATA
+GLOBALNAME vcc100_ws2_32_fakes_asm
+
+MAKE_IMPORT_ENTRY getaddrinfo, 16
+MAKE_IMPORT_ENTRY freeaddrinfo, 4
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32.cpp b/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32.cpp
new file mode 100644
index 00000000..b12f253e
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes-ws2_32.cpp
@@ -0,0 +1,113 @@
+/* $Id: vcc-fakes-ws2_32.cpp $ */
+/** @file
+ * IPRT - Tricks to make the Visual C++ 2010 CRT work on NT4, W2K and XP - WS2_32.DLL.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cdefs.h>
+#include <iprt/types.h>
+#include <iprt/asm.h>
+#include <iprt/string.h>
+
+#ifndef RT_ARCH_X86
+# error "This code is X86 only"
+#endif
+
+#define getaddrinfo                             Ignore_getaddrinfo
+#define freeaddrinfo                            Ignore_freeaddrinfo
+
+#include <iprt/win/winsock2.h>
+#include <iprt/win/ws2tcpip.h>
+
+#undef getaddrinfo
+#undef freeaddrinfo
+
+
+/** Dynamically resolves an kernel32 API.   */
+#define RESOLVE_ME(ApiNm) \
+    static bool volatile    s_fInitialized = false; \
+    static decltype(ApiNm) *s_pfnApi = NULL; \
+    decltype(ApiNm)        *pfnApi; \
+    if (s_fInitialized) \
+        pfnApi = s_pfnApi; \
+    else \
+    { \
+        pfnApi = (decltype(pfnApi))GetProcAddress(GetModuleHandleW(L"wc2_32.dll"), #ApiNm); \
+        s_pfnApi = pfnApi; \
+        s_fInitialized = true; \
+    } do {} while (0) \
+
+
+extern "C"
+__declspec(dllexport)
+int WINAPI getaddrinfo(const char *pszNodeName, const char *pszServiceName, const struct addrinfo *pHints,
+                       struct addrinfo **ppResults)
+{
+    RESOLVE_ME(getaddrinfo);
+    if (pfnApi)
+        return pfnApi(pszNodeName, pszServiceName, pHints, ppResults);
+
+    /** @todo  fallback */
+    WSASetLastError(WSAEAFNOSUPPORT);
+    return WSAEAFNOSUPPORT;
+}
+
+
+
+extern "C"
+__declspec(dllexport)
+void WINAPI freeaddrinfo(struct addrinfo *pResults)
+{
+    RESOLVE_ME(freeaddrinfo);
+    if (pfnApi)
+        pfnApi(pResults);
+    else
+    {
+        Assert(!pResults);
+        /** @todo  fallback */
+    }
+}
+
+
+
+/* Dummy to force dragging in this object in the link, so the linker
+   won't accidentally use the symbols from kernel32. */
+extern "C" int vcc100_ws2_32_fakes_cpp(void)
+{
+    return 42;
+}
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes.h b/src/VBox/Runtime/r3/win/vcc-fakes.h
new file mode 100644
index 00000000..6e72e2b8
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes.h
@@ -0,0 +1,155 @@
+/* $Id: vcc-fakes.h $ */
+/** @file
+ * IPRT - Common macros for the Visual C++ 2010+ CRT import fakes.
+ */
+
+/*
+ * Copyright (C) 2012-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+#ifndef IPRT_INCLUDED_SRC_r3_win_vcc_fakes_h
+#define IPRT_INCLUDED_SRC_r3_win_vcc_fakes_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#ifdef RT_STRICT
+# include <stdio.h> /* _snprintf */
+#endif
+
+
+/** @def MY_ASSERT
+ * We use a special assertion macro here to avoid dragging in IPRT bits in
+ * places which cannot handle it (direct GA 3D bits or something like that).
+ *
+ * Turns out snprintf is off limits too.  Needs Locale info and runs out of
+ * stack
+ */
+#ifdef RT_STRICT
+# if 1
+#  define MY_ASSERT(a_Expr, g_szMsg) \
+    do { \
+        if ((a_Expr)) \
+        { /*likely*/ } \
+        else \
+        { \
+            OutputDebugStringA("Assertion failed on line " RT_XSTR(__LINE__) ": " RT_XSTR(a_Expr) "\n"); \
+            OutputDebugStringA("Assertion message: " g_szMsg "\n"); \
+            RT_BREAKPOINT(); \
+        } \
+    } while (0)
+# define MY_ASSERT_STMT_RETURN(a_Expr, a_Stmt, a_rc) \
+    do { \
+        if (a_Expr) \
+        { /* likely */ } \
+        else \
+        { \
+            OutputDebugStringA("Assertion failed on line " RT_XSTR(__LINE__) ": " RT_XSTR(a_Expr) "\n"); \
+            RT_BREAKPOINT(); \
+            a_Stmt; \
+            return (a_rc); \
+        } \
+    } while (0)
+# else
+#  define MY_ASSERT(a_Expr, ...) \
+    do { \
+        if ((a_Expr)) \
+        { /*likely*/ } \
+        else \
+        { \
+            char szTmp[256]; \
+            _snprintf(szTmp, sizeof(szTmp), "Assertion failed on line %u in '%s': %s", __LINE__, __PRETTY_FUNCTION__, #a_Expr); \
+            OutputDebugStringA(szTmp); \
+            _snprintf(szTmp, sizeof(szTmp), __VA_ARGS__); \
+            OutputDebugStringA(szTmp); \
+            RT_BREAKPOINT(); \
+        } \
+    } while (0)
+# endif
+#else
+# define MY_ASSERT(a_Expr, ...) do { } while (0)
+# define MY_ASSERT_STMT_RETURN(a_Expr, a_Stmt, a_rc) \
+    do { if (a_Expr) { /* likely */ } else { a_Stmt; return (a_rc); }} while (0)
+#endif
+
+
+/** Dynamically resolves an NTDLL API we need.   */
+#define RESOLVE_NTDLL_API(ApiNm) \
+    static bool volatile    s_fInitialized##ApiNm = false; \
+    static decltype(ApiNm) *s_pfn##ApiNm = NULL; \
+    decltype(ApiNm)        *pfn##ApiNm; \
+    if (s_fInitialized##ApiNm) \
+        pfn##ApiNm = s_pfn##ApiNm; \
+    else \
+    { \
+        pfn##ApiNm = (decltype(pfn##ApiNm))GetProcAddress(GetModuleHandleW(L"ntdll"), #ApiNm); \
+        s_pfn##ApiNm = pfn##ApiNm; \
+        s_fInitialized##ApiNm = true; \
+    } do {} while (0)
+
+
+/** Declare a kernel32 API.
+ * @note We are not exporting them as that causes duplicate symbol troubles in
+ *       the OpenGL bits. */
+#define DECL_KERNEL32(a_Type) extern "C" a_Type WINAPI
+
+
+/** Ignore comments. */
+#define COMMENT(a_Text)
+
+/** Used for MAKE_IMPORT_ENTRY when declaring external g_pfnXxxx variables. */
+#define DECLARE_FUNCTION_POINTER(a_Name, a_cb) extern "C" decltype(a_Name) *RT_CONCAT(g_pfn, a_Name);
+
+/** Used in the InitFakes method to decl are uCurVersion used by assertion. */
+#ifdef RT_STRICT
+# define CURRENT_VERSION_VARIABLE() \
+    unsigned uCurVersion = GetVersion(); \
+    uCurVersion = ((uCurVersion & 0xff) << 8) | ((uCurVersion >> 8) & 0xff)
+#else
+# define CURRENT_VERSION_VARIABLE() (void)0
+#endif
+
+
+/** Used for MAKE_IMPORT_ENTRY when resolving an import. */
+#define RESOLVE_IMPORT(a_uMajorVer, a_uMinorVer, a_Name, a_cb) \
+    do { \
+        FARPROC pfnApi = GetProcAddress(hmod, #a_Name); \
+        if (pfnApi) \
+            RT_CONCAT(g_pfn, a_Name) = (decltype(a_Name) *)pfnApi; \
+        else \
+        { \
+            MY_ASSERT(uCurVersion < (((a_uMajorVer) << 8) | (a_uMinorVer)), #a_Name); \
+            RT_CONCAT(g_pfn, a_Name) = RT_CONCAT(Fake_,a_Name); \
+        } \
+    } while (0);
+
+
+#endif /* !IPRT_INCLUDED_SRC_r3_win_vcc_fakes_h */
+
diff --git a/src/VBox/Runtime/r3/win/vcc-fakes.mac b/src/VBox/Runtime/r3/win/vcc-fakes.mac
new file mode 100644
index 00000000..37c51543
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/vcc-fakes.mac
@@ -0,0 +1,76 @@
+; $Id: vcc-fakes.mac $
+;; @file
+; IPRT - Common macros for the Visual C++ 2010+ CRT import fakes.
+;
+
+;
+; Copyright (C) 2006-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;
+
+
+%include "iprt/asmdefs.mac"
+
+%ifndef RT_ARCH_X86
+ %error "This is x86 only code.
+%endif
+
+
+;;
+; Fakes an API import table entry.
+;
+; @param 1  The function name
+; @param 2  Number of bytes of parameters for x86.
+%macro MAKE_IMPORT_ENTRY_INTERNAL 2
+
+BEGINDATA
+extern _FakeResolve_ %+ FAKE_MODULE_NAME
+
+extern _Fake_ %+ %1 %+ @ %+ %2
+global __imp__ %+ %1 %+ @ %+ %2         ; The import address table (IAT) entry name.
+__imp__ %+ %1 %+ @ %+ %2:
+global _g_pfn %+ %1                     ; C accessible label.
+_g_pfn %+ %1:
+        dd      FakeLazyInit_ %+ %1
+
+BEGINCODE
+FakeLazyInit_ %+ %1:
+        pusha
+        call    _FakeResolve_ %+ FAKE_MODULE_NAME
+        popa
+global _ %+ %1 %+ @ %+ %2               ; The imported function stub.
+_ %+ %1 %+ @ %+ %2:
+        jmp     [_g_pfn %+ %1]
+
+
+%endmacro
+
+%define MAKE_IMPORT_ENTRY(a_uMajorVer, a_uMinorVer, a_Name, a_cbParams) MAKE_IMPORT_ENTRY_INTERNAL a_Name, a_cbParams
+%define COMMENT(a_Text)
+
diff --git a/src/VBox/Runtime/r3/xml.cpp b/src/VBox/Runtime/r3/xml.cpp
new file mode 100644
index 00000000..a6661760
--- /dev/null
+++ b/src/VBox/Runtime/r3/xml.cpp
@@ -0,0 +1,2357 @@
+/* $Id: xml.cpp $ */
+/** @file
+ * IPRT - XML Manipulation API.
+ *
+ * @note Not available in no-CRT mode because it relies too heavily on
+ *       exceptions, as well as using std::list and std::map.
+ */
+
+/*
+ * Copyright (C) 2007-2023 Oracle and/or its affiliates.
+ *
+ * This file is part of VirtualBox base platform packages, as
+ * available from https://www.virtualbox.org.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, in version 3 of the
+ * License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses>.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+ * in the VirtualBox distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ *
+ * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/cpp/xml.h>
+
+#include <iprt/dir.h>
+#include <iprt/file.h>
+#include <iprt/err.h>
+#include <iprt/log.h>
+#include <iprt/param.h>
+#include <iprt/path.h>
+#include <iprt/cpp/lock.h>
+
+#include <libxml/tree.h>
+#include <libxml/parser.h>
+#include <libxml/globals.h>
+#include <libxml/xmlIO.h>
+#include <libxml/xmlsave.h>
+#include <libxml/uri.h>
+
+#include <libxml/xmlschemas.h>
+
+#include <map>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/**
+ * Global module initialization structure. This is to wrap non-reentrant bits
+ * of libxml, among other things.
+ *
+ * The constructor and destructor of this structure are used to perform global
+ * module initialization and cleanup. There must be only one global variable of
+ * this structure.
+ */
+static class Global
+{
+public:
+
+    Global()
+    {
+        /* Check the parser version. The docs say it will kill the app if
+         * there is a serious version mismatch, but I couldn't find it in the
+         * source code (it only prints the error/warning message to the console) so
+         * let's leave it as is for informational purposes. */
+        LIBXML_TEST_VERSION
+
+        /* Init libxml */
+        xmlInitParser();
+
+        /* Save the default entity resolver before someone has replaced it */
+        sxml.defaultEntityLoader = xmlGetExternalEntityLoader();
+    }
+
+    ~Global()
+    {
+        /* Shutdown libxml */
+        xmlCleanupParser();
+    }
+
+    struct
+    {
+        xmlExternalEntityLoader defaultEntityLoader;
+
+        /** Used to provide some thread safety missing in libxml2 (see e.g.
+         *  XmlTreeBackend::read()) */
+        RTCLockMtx lock;
+    }
+    sxml;  /* XXX naming this xml will break with gcc-3.3 */
+} gGlobal;
+
+
+
+namespace xml
+{
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// Exceptions
+//
+////////////////////////////////////////////////////////////////////////////////
+
+LogicError::LogicError(RT_SRC_POS_DECL)
+    : RTCError(NULL)
+{
+    char *msg = NULL;
+    RTStrAPrintf(&msg, "In '%s', '%s' at #%d",
+                 pszFunction, pszFile, iLine);
+    setWhat(msg);
+    RTStrFree(msg);
+}
+
+XmlError::XmlError(xmlErrorPtr aErr)
+{
+    if (!aErr)
+        throw EInvalidArg(RT_SRC_POS);
+
+    char *msg = Format(aErr);
+    setWhat(msg);
+    RTStrFree(msg);
+}
+
+/**
+ * Composes a single message for the given error. The caller must free the
+ * returned string using RTStrFree() when no more necessary.
+ */
+/* static */ char *XmlError::Format(xmlErrorPtr aErr)
+{
+    const char *msg = aErr->message ? aErr->message : "<none>";
+    size_t msgLen = strlen(msg);
+    /* strip spaces, trailing EOLs and dot-like char */
+    while (msgLen && strchr(" \n.?!", msg [msgLen - 1]))
+        --msgLen;
+
+    char *finalMsg = NULL;
+    RTStrAPrintf(&finalMsg, "%.*s.\nLocation: '%s', line %d (%d), column %d",
+                 msgLen, msg, aErr->file, aErr->line, aErr->int1, aErr->int2);
+
+    return finalMsg;
+}
+
+EIPRTFailure::EIPRTFailure(int aRC, const char *pszContextFmt, ...)
+    : RuntimeError(NULL)
+    , mRC(aRC)
+{
+    va_list va;
+    va_start(va, pszContextFmt);
+    m_strMsg.printfVNoThrow(pszContextFmt, va);
+    va_end(va);
+    m_strMsg.appendPrintfNoThrow(" %Rrc (%Rrs)", aRC, aRC);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// File Class
+//
+//////////////////////////////////////////////////////////////////////////////
+
+struct File::Data
+{
+    Data(RTFILE a_hHandle, const char *a_pszFilename, bool a_fFlushOnClose)
+        : strFileName(a_pszFilename)
+        , handle(a_hHandle)
+        , opened(a_hHandle != NIL_RTFILE)
+        , flushOnClose(a_fFlushOnClose)
+    { }
+
+    ~Data()
+    {
+        if (flushOnClose)
+        {
+            RTFileFlush(handle);
+            if (!strFileName.isEmpty())
+                RTDirFlushParent(strFileName.c_str());
+        }
+
+        if (opened)
+        {
+            RTFileClose(handle);
+            handle = NIL_RTFILE;
+            opened = false;
+        }
+    }
+
+    RTCString strFileName;
+    RTFILE handle;
+    bool opened : 1;
+    bool flushOnClose : 1;
+};
+
+File::File(Mode aMode, const char *aFileName, bool aFlushIt /* = false */)
+    : m(NULL)
+{
+    /* Try open the file first, as the destructor will not be invoked if we throw anything from here. For details see:
+       https://stackoverflow.com/questions/9971782/destructor-not-invoked-when-an-exception-is-thrown-in-the-constructor */
+    uint32_t flags = 0;
+    const char *pcszMode = "???";
+    switch (aMode)
+    {
+        /** @todo change to RTFILE_O_DENY_WRITE where appropriate. */
+        case Mode_Read:
+            flags = RTFILE_O_READ      | RTFILE_O_OPEN           | RTFILE_O_DENY_NONE;
+            pcszMode = "reading";
+            break;
+        case Mode_WriteCreate:      // fail if file exists
+            flags = RTFILE_O_WRITE     | RTFILE_O_CREATE         | RTFILE_O_DENY_NONE;
+            pcszMode = "writing";
+            break;
+        case Mode_Overwrite:        // overwrite if file exists
+            flags = RTFILE_O_WRITE     | RTFILE_O_CREATE_REPLACE | RTFILE_O_DENY_NONE;
+            pcszMode = "overwriting";
+            break;
+        case Mode_ReadWrite:
+            flags = RTFILE_O_READWRITE | RTFILE_O_OPEN           | RTFILE_O_DENY_NONE;
+            pcszMode = "reading/writing";
+            break;
+    }
+    RTFILE hFile = NIL_RTFILE;
+    int vrc = RTFileOpen(&hFile, aFileName, flags);
+    if (RT_FAILURE(vrc))
+        throw EIPRTFailure(vrc, "Runtime error opening '%s' for %s", aFileName, pcszMode);
+
+    /* Now we can create the data and stuff: */
+    try
+    {
+        m = new Data(hFile, aFileName, aFlushIt && (flags & RTFILE_O_ACCESS_MASK) != RTFILE_O_READ);
+    }
+    catch (std::bad_alloc &)
+    {
+        RTFileClose(hFile);
+        throw;
+    }
+}
+
+File::File(RTFILE aHandle, const char *aFileName /* = NULL */, bool aFlushIt /* = false */)
+    : m(NULL)
+{
+    if (aHandle == NIL_RTFILE)
+        throw EInvalidArg(RT_SRC_POS);
+
+    m = new Data(aHandle, aFileName, aFlushIt);
+
+    setPos(0);
+}
+
+File::~File()
+{
+    if (m)
+    {
+        delete m;
+        m = NULL;
+    }
+}
+
+const char *File::uri() const
+{
+    return m->strFileName.c_str();
+}
+
+uint64_t File::pos() const
+{
+    uint64_t p = 0;
+    int vrc = RTFileSeek(m->handle, 0, RTFILE_SEEK_CURRENT, &p);
+    if (RT_SUCCESS(vrc))
+        return p;
+
+    throw EIPRTFailure(vrc, "Runtime error seeking in file '%s'", m->strFileName.c_str());
+}
+
+void File::setPos(uint64_t aPos)
+{
+    uint64_t p = 0;
+    unsigned method = RTFILE_SEEK_BEGIN;
+    int vrc = VINF_SUCCESS;
+
+    /* check if we overflow int64_t and move to INT64_MAX first */
+    if ((int64_t)aPos < 0)
+    {
+        vrc = RTFileSeek(m->handle, INT64_MAX, method, &p);
+        aPos -= (uint64_t)INT64_MAX;
+        method = RTFILE_SEEK_CURRENT;
+    }
+    /* seek the rest */
+    if (RT_SUCCESS(vrc))
+        vrc = RTFileSeek(m->handle, (int64_t) aPos, method, &p);
+    if (RT_SUCCESS(vrc))
+        return;
+
+    throw EIPRTFailure(vrc, "Runtime error seeking in file '%s'", m->strFileName.c_str());
+}
+
+int File::read(char *aBuf, int aLen)
+{
+    size_t len = aLen;
+    int vrc = RTFileRead(m->handle, aBuf, len, &len);
+    if (RT_SUCCESS(vrc))
+        return (int)len;
+
+    throw EIPRTFailure(vrc, "Runtime error reading from file '%s'", m->strFileName.c_str());
+}
+
+int File::write(const char *aBuf, int aLen)
+{
+    size_t len = aLen;
+    int vrc = RTFileWrite(m->handle, aBuf, len, &len);
+    if (RT_SUCCESS(vrc))
+        return (int)len;
+
+    throw EIPRTFailure(vrc, "Runtime error writing to file '%s'", m->strFileName.c_str());
+}
+
+void File::truncate()
+{
+    int vrc = RTFileSetSize(m->handle, pos());
+    if (RT_SUCCESS(vrc))
+        return;
+
+    throw EIPRTFailure(vrc, "Runtime error truncating file '%s'", m->strFileName.c_str());
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// MemoryBuf Class
+//
+//////////////////////////////////////////////////////////////////////////////
+
+struct MemoryBuf::Data
+{
+    Data()
+        : buf(NULL), len(0), uri(NULL), pos(0) {}
+
+    const char *buf;
+    size_t len;
+    char *uri;
+
+    size_t pos;
+};
+
+MemoryBuf::MemoryBuf(const char *aBuf, size_t aLen, const char *aURI /* = NULL */)
+    : m(new Data())
+{
+    if (aBuf == NULL)
+        throw EInvalidArg(RT_SRC_POS);
+
+    m->buf = aBuf;
+    m->len = aLen;
+    m->uri = RTStrDup(aURI);
+}
+
+MemoryBuf::~MemoryBuf()
+{
+    RTStrFree(m->uri);
+}
+
+const char *MemoryBuf::uri() const
+{
+    return m->uri;
+}
+
+uint64_t MemoryBuf::pos() const
+{
+    return m->pos;
+}
+
+void MemoryBuf::setPos(uint64_t aPos)
+{
+    size_t off = (size_t)aPos;
+    if ((uint64_t) off != aPos)
+        throw EInvalidArg();
+
+    if (off > m->len)
+        throw EInvalidArg();
+
+    m->pos = off;
+}
+
+int MemoryBuf::read(char *aBuf, int aLen)
+{
+    if (m->pos >= m->len)
+        return 0 /* nothing to read */;
+
+    size_t len = m->pos + aLen < m->len ? aLen : m->len - m->pos;
+    memcpy(aBuf, m->buf + m->pos, len);
+    m->pos += len;
+
+    return (int)len;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// GlobalLock class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+struct GlobalLock::Data
+{
+    PFNEXTERNALENTITYLOADER pfnOldLoader;
+    RTCLock lock;
+
+    Data()
+        : pfnOldLoader(NULL)
+        , lock(gGlobal.sxml.lock)
+    {
+    }
+};
+
+GlobalLock::GlobalLock()
+    : m(new Data())
+{
+}
+
+GlobalLock::~GlobalLock()
+{
+    if (m->pfnOldLoader)
+        xmlSetExternalEntityLoader(m->pfnOldLoader);
+    delete m;
+    m = NULL;
+}
+
+void GlobalLock::setExternalEntityLoader(PFNEXTERNALENTITYLOADER pfnLoader)
+{
+    m->pfnOldLoader = (PFNEXTERNALENTITYLOADER)xmlGetExternalEntityLoader();
+    xmlSetExternalEntityLoader(pfnLoader);
+}
+
+// static
+xmlParserInput* GlobalLock::callDefaultLoader(const char *aURI,
+                                              const char *aID,
+                                              xmlParserCtxt *aCtxt)
+{
+    return gGlobal.sxml.defaultEntityLoader(aURI, aID, aCtxt);
+}
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// Node class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+Node::Node(EnumType type,
+           Node *pParent,
+           PRTLISTANCHOR pListAnchor,
+           xmlNode *pLibNode,
+           xmlAttr *pLibAttr)
+    : m_Type(type)
+    , m_pParent(pParent)
+    , m_pLibNode(pLibNode)
+    , m_pLibAttr(pLibAttr)
+    , m_pcszNamespacePrefix(NULL)
+    , m_pcszNamespaceHref(NULL)
+    , m_pcszName(NULL)
+    , m_pParentListAnchor(pListAnchor)
+{
+    RTListInit(&m_listEntry);
+}
+
+Node::~Node()
+{
+}
+
+/**
+ * Returns the name of the node, which is either the element name or
+ * the attribute name. For other node types it probably returns NULL.
+ * @return
+ */
+const char *Node::getName() const
+{
+    return m_pcszName;
+}
+
+/**
+ * Returns the name of the node, which is either the element name or
+ * the attribute name. For other node types it probably returns NULL.
+ * @return
+ */
+const char *Node::getPrefix() const
+{
+    return m_pcszNamespacePrefix;
+}
+
+/**
+ * Returns the XML namespace URI, which is the attribute name. For other node types it probably
+ * returns NULL.
+ * @return
+ */
+const char *Node::getNamespaceURI() const
+{
+    return m_pcszNamespaceHref;
+}
+
+/**
+ * Variant of nameEquals that checks the namespace as well.
+ * @param pcszNamespace
+ * @param pcsz
+ * @return
+ */
+bool Node::nameEqualsNS(const char *pcszNamespace, const char *pcsz) const
+{
+    if (m_pcszName == pcsz)
+        return true;
+    if (m_pcszName == NULL)
+        return false;
+    if (pcsz == NULL)
+        return false;
+    if (strcmp(m_pcszName, pcsz))
+        return false;
+
+    // name matches: then check namespaces as well
+    if (!pcszNamespace)
+        return true;
+    // caller wants namespace:
+    if (!m_pcszNamespacePrefix)
+        // but node has no namespace:
+        return false;
+    return !strcmp(m_pcszNamespacePrefix, pcszNamespace);
+}
+
+/**
+ * Variant of nameEquals that checks the namespace as well.
+ *
+ * @returns true if equal, false if not.
+ * @param   pcsz            The element name.
+ * @param   cchMax          The maximum number of character from @a pcsz to
+ *                          match.
+ * @param   pcszNamespace   The name space prefix or NULL (default).
+ */
+bool Node::nameEqualsN(const char *pcsz, size_t cchMax, const char *pcszNamespace /* = NULL*/) const
+{
+    /* Match the name. */
+    if (!m_pcszName)
+        return false;
+    if (!pcsz || cchMax == 0)
+        return false;
+    if (strncmp(m_pcszName, pcsz, cchMax))
+        return false;
+    if (strlen(m_pcszName) > cchMax)
+        return false;
+
+    /* Match name space. */
+    if (!pcszNamespace)
+        return true;    /* NULL, anything goes. */
+    if (!m_pcszNamespacePrefix)
+        return false;   /* Element has no namespace. */
+    return !strcmp(m_pcszNamespacePrefix, pcszNamespace);
+}
+
+/**
+ * Returns the value of a node. If this node is an attribute, returns
+ * the attribute value; if this node is an element, then this returns
+ * the element text content.
+ * @return
+ */
+const char *Node::getValue() const
+{
+    if (   m_pLibAttr
+        && m_pLibAttr->children
+        )
+        // libxml hides attribute values in another node created as a
+        // single child of the attribute node, and it's in the content field
+        return (const char *)m_pLibAttr->children->content;
+
+    if (   m_pLibNode
+        && m_pLibNode->children)
+        return (const char *)m_pLibNode->children->content;
+
+    return NULL;
+}
+
+/**
+ * Returns the value of a node. If this node is an attribute, returns
+ * the attribute value; if this node is an element, then this returns
+ * the element text content.
+ * @return
+ * @param   cchValueLimit   If the length of the returned value exceeds this
+ *                          limit a EIPRTFailure exception will be thrown.
+ */
+const char *Node::getValueN(size_t cchValueLimit) const
+{
+    if (   m_pLibAttr
+        && m_pLibAttr->children
+        )
+    {
+        // libxml hides attribute values in another node created as a
+        // single child of the attribute node, and it's in the content field
+        AssertStmt(strlen((const char *)m_pLibAttr->children->content) <= cchValueLimit, throw EIPRTFailure(VERR_BUFFER_OVERFLOW, "Attribute '%s' exceeds limit of %zu bytes", m_pcszName, cchValueLimit));
+        return (const char *)m_pLibAttr->children->content;
+    }
+
+    if (   m_pLibNode
+        && m_pLibNode->children)
+    {
+        AssertStmt(strlen((const char *)m_pLibNode->children->content) <= cchValueLimit, throw EIPRTFailure(VERR_BUFFER_OVERFLOW, "Element '%s' exceeds limit of %zu bytes", m_pcszName, cchValueLimit));
+        return (const char *)m_pLibNode->children->content;
+    }
+
+    return NULL;
+}
+
+/**
+ * Copies the value of a node into the given integer variable.
+ * Returns TRUE only if a value was found and was actually an
+ * integer of the given type.
+ * @return
+ */
+bool Node::copyValue(int32_t &i) const
+{
+    const char *pcsz;
+    if (    ((pcsz = getValue()))
+         && (VINF_SUCCESS == RTStrToInt32Ex(pcsz, NULL, 10, &i))
+       )
+        return true;
+
+    return false;
+}
+
+/**
+ * Copies the value of a node into the given integer variable.
+ * Returns TRUE only if a value was found and was actually an
+ * integer of the given type.
+ * @return
+ */
+bool Node::copyValue(uint32_t &i) const
+{
+    const char *pcsz;
+    if (    ((pcsz = getValue()))
+         && (VINF_SUCCESS == RTStrToUInt32Ex(pcsz, NULL, 10, &i))
+       )
+        return true;
+
+    return false;
+}
+
+/**
+ * Copies the value of a node into the given integer variable.
+ * Returns TRUE only if a value was found and was actually an
+ * integer of the given type.
+ * @return
+ */
+bool Node::copyValue(int64_t &i) const
+{
+    const char *pcsz;
+    if (    ((pcsz = getValue()))
+         && (VINF_SUCCESS == RTStrToInt64Ex(pcsz, NULL, 10, &i))
+       )
+        return true;
+
+    return false;
+}
+
+/**
+ * Copies the value of a node into the given integer variable.
+ * Returns TRUE only if a value was found and was actually an
+ * integer of the given type.
+ * @return
+ */
+bool Node::copyValue(uint64_t &i) const
+{
+    const char *pcsz;
+    if (    ((pcsz = getValue()))
+         && (VINF_SUCCESS == RTStrToUInt64Ex(pcsz, NULL, 10, &i))
+       )
+        return true;
+
+    return false;
+}
+
+/**
+ * Returns the line number of the current node in the source XML file.
+ * Useful for error messages.
+ * @return
+ */
+int Node::getLineNumber() const
+{
+    if (m_pLibAttr)
+        return m_pParent->m_pLibNode->line;
+
+    return m_pLibNode->line;
+}
+
+/**
+ * Private element constructor.
+ *
+ * @param   pElmRoot    Pointer to the root element.
+ * @param   pParent     Pointer to the parent element (always an ElementNode,
+ *                      despite the type).  NULL for the root node.
+ * @param   pListAnchor Pointer to the m_children member of the parent.  NULL
+ *                      for the root node.
+ * @param   pLibNode    Pointer to the libxml2 node structure.
+ */
+ElementNode::ElementNode(const ElementNode *pElmRoot,
+                         Node *pParent,
+                         PRTLISTANCHOR pListAnchor,
+                         xmlNode *pLibNode)
+    : Node(IsElement,
+           pParent,
+           pListAnchor,
+           pLibNode,
+           NULL)
+{
+    m_pElmRoot = pElmRoot ? pElmRoot : this; // If NULL is passed, then this is the root element.
+    m_pcszName = (const char *)pLibNode->name;
+
+    if (pLibNode->ns)
+    {
+        m_pcszNamespacePrefix = (const char *)m_pLibNode->ns->prefix;
+        m_pcszNamespaceHref = (const char *)m_pLibNode->ns->href;
+    }
+
+    RTListInit(&m_children);
+    RTListInit(&m_attributes);
+}
+
+ElementNode::~ElementNode()
+{
+    Node *pCur, *pNext;
+    RTListForEachSafeCpp(&m_children, pCur, pNext, Node, m_listEntry)
+    {
+        delete pCur;
+    }
+    RTListInit(&m_children);
+
+    RTListForEachSafeCpp(&m_attributes, pCur, pNext, Node, m_listEntry)
+    {
+        delete pCur;
+    }
+    RTListInit(&m_attributes);
+}
+
+
+ElementNode const *ElementNode::getNextTreeElement(ElementNode const *pElmRoot /*= NULL */) const
+{
+    /*
+     * Consider children first.
+     */
+    ElementNode const *pChild = getFirstChildElement();
+    if (pChild)
+        return pChild;
+
+    /*
+     * Then siblings, aunts and uncles.
+     */
+    ElementNode const *pCur = this;
+    do
+    {
+        ElementNode const *pSibling = pCur->getNextSibilingElement();
+        if (pSibling != NULL)
+            return pSibling;
+
+        pCur = static_cast<const xml::ElementNode *>(pCur->m_pParent);
+        Assert(pCur || pCur == pElmRoot);
+    } while (pCur != pElmRoot);
+
+    return NULL;
+}
+
+
+/**
+ * Private implementation.
+ *
+ * @param   pElmRoot        The root element.
+ */
+/*static*/ void ElementNode::buildChildren(ElementNode *pElmRoot)       // protected
+{
+    for (ElementNode *pCur = pElmRoot; pCur; pCur = pCur->getNextTreeElement(pElmRoot))
+    {
+        /*
+         * Go thru this element's attributes creating AttributeNodes for them.
+         */
+        for (xmlAttr *pLibAttr = pCur->m_pLibNode->properties; pLibAttr; pLibAttr = pLibAttr->next)
+        {
+            AttributeNode *pNew = new AttributeNode(pElmRoot, pCur, &pCur->m_attributes, pLibAttr);
+            RTListAppend(&pCur->m_attributes, &pNew->m_listEntry);
+        }
+
+        /*
+         * Go thru this element's child elements (element and text nodes).
+         */
+        for (xmlNodePtr pLibNode = pCur->m_pLibNode->children; pLibNode; pLibNode = pLibNode->next)
+        {
+            Node *pNew;
+            if (pLibNode->type == XML_ELEMENT_NODE)
+                pNew = new ElementNode(pElmRoot, pCur, &pCur->m_children, pLibNode);
+            else if (pLibNode->type == XML_TEXT_NODE)
+                pNew = new ContentNode(pCur, &pCur->m_children, pLibNode);
+            else
+                continue;
+            RTListAppend(&pCur->m_children, &pNew->m_listEntry);
+        }
+    }
+}
+
+
+/**
+ * Builds a list of direct child elements of the current element that
+ * match the given string; if pcszMatch is NULL, all direct child
+ * elements are returned.
+ * @param children out: list of nodes to which children will be appended.
+ * @param pcszMatch in: match string, or NULL to return all children.
+ * @return Number of items appended to the list (0 if none).
+ */
+int ElementNode::getChildElements(ElementNodesList &children,
+                                  const char *pcszMatch /*= NULL*/)
+    const
+{
+    int i = 0;
+    Node *p;
+    RTListForEachCpp(&m_children, p, Node, m_listEntry)
+    {
+        // export this child node if ...
+        if (p->isElement())
+            if (   !pcszMatch                       // ... the caller wants all nodes or ...
+                || !strcmp(pcszMatch, p->getName()) // ... the element name matches.
+               )
+            {
+                children.push_back(static_cast<ElementNode *>(p));
+                ++i;
+            }
+    }
+    return i;
+}
+
+/**
+ * Returns the first child element whose name matches pcszMatch.
+ *
+ * @param pcszNamespace Namespace prefix (e.g. "vbox") or NULL to match any namespace.
+ * @param pcszMatch Element name to match.
+ * @return
+ */
+const ElementNode *ElementNode::findChildElementNS(const char *pcszNamespace, const char *pcszMatch) const
+{
+    Node *p;
+    RTListForEachCpp(&m_children, p, Node, m_listEntry)
+    {
+        if (p->isElement())
+        {
+            ElementNode *pelm = static_cast<ElementNode*>(p);
+            if (pelm->nameEqualsNS(pcszNamespace, pcszMatch))
+                return pelm;
+        }
+    }
+    return NULL;
+}
+
+/**
+ * Returns the first child element whose "id" attribute matches pcszId.
+ * @param pcszId identifier to look for.
+ * @return child element or NULL if not found.
+ */
+const ElementNode *ElementNode::findChildElementFromId(const char *pcszId) const
+{
+    const Node *p;
+    RTListForEachCpp(&m_children, p, Node, m_listEntry)
+    {
+        if (p->isElement())
+        {
+            const ElementNode   *pElm  = static_cast<const ElementNode *>(p);
+            const AttributeNode *pAttr = pElm->findAttribute("id");
+            if (pAttr && !strcmp(pAttr->getValue(), pcszId))
+                return pElm;
+        }
+    }
+    return NULL;
+}
+
+
+const ElementNode *ElementNode::findChildElementP(const char *pcszPath, const char *pcszNamespace /*= NULL*/) const
+{
+    size_t cchThis = strchr(pcszPath, '/') - pcszPath;
+    if (cchThis == (size_t)((const char *)0 - pcszPath))
+        return findChildElementNS(pcszNamespace, pcszPath);
+
+    /** @todo Can be done without recursion as we have both sibling lists and parent
+     *        pointers in this variant.  */
+    const Node *p;
+    RTListForEachCpp(&m_children, p, Node, m_listEntry)
+    {
+        if (p->isElement())
+        {
+            const ElementNode *pElm = static_cast<const ElementNode *>(p);
+            if (pElm->nameEqualsN(pcszPath, cchThis, pcszNamespace))
+            {
+                pElm = findChildElementP(pcszPath + cchThis, pcszNamespace);
+                if (pElm)
+                    return pElm;
+            }
+        }
+    }
+
+    return NULL;
+}
+
+const ElementNode *ElementNode::getFirstChildElement() const
+{
+    const Node *p;
+    RTListForEachCpp(&m_children, p, Node, m_listEntry)
+    {
+        if (p->isElement())
+            return static_cast<const ElementNode *>(p);
+    }
+    return NULL;
+}
+
+const ElementNode *ElementNode::getLastChildElement() const
+{
+    const Node *p;
+    RTListForEachReverseCpp(&m_children, p, Node, m_listEntry)
+    {
+        if (p->isElement())
+            return static_cast<const ElementNode *>(p);
+    }
+    return NULL;
+}
+
+const ElementNode *ElementNode::getPrevSibilingElement() const
+{
+    if (!m_pParent)
+        return NULL;
+    const Node *pSibling = this;
+    for (;;)
+    {
+        pSibling = RTListGetPrevCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
+        if (!pSibling)
+            return NULL;
+        if (pSibling->isElement())
+            return static_cast<const ElementNode *>(pSibling);
+    }
+}
+
+const ElementNode *ElementNode::getNextSibilingElement() const
+{
+    if (!m_pParent)
+        return NULL;
+    const Node *pSibling = this;
+    for (;;)
+    {
+        pSibling = RTListGetNextCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
+        if (!pSibling)
+            return NULL;
+        if (pSibling->isElement())
+            return static_cast<const ElementNode *>(pSibling);
+    }
+}
+
+const ElementNode *ElementNode::findPrevSibilingElement(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
+{
+    if (!m_pParent)
+        return NULL;
+    const Node *pSibling = this;
+    for (;;)
+    {
+        pSibling = RTListGetPrevCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
+        if (!pSibling)
+            return NULL;
+        if (pSibling->isElement())
+        {
+            const ElementNode *pElem = static_cast<const ElementNode *>(pSibling);
+            if (pElem->nameEqualsNS(pcszNamespace, pcszMatch))
+                return pElem;
+        }
+    }
+}
+
+const ElementNode *ElementNode::findNextSibilingElement(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
+{
+    if (!m_pParent)
+        return NULL;
+    const Node *pSibling = this;
+    for (;;)
+    {
+        pSibling = RTListGetNextCpp(m_pParentListAnchor, pSibling, const Node, m_listEntry);
+        if (!pSibling)
+            return NULL;
+        if (pSibling->isElement())
+        {
+            const ElementNode *pElem = static_cast<const ElementNode *>(pSibling);
+            if (pElem->nameEqualsNS(pcszNamespace, pcszMatch))
+                return pElem;
+        }
+    }
+}
+
+
+/**
+ * Looks up the given attribute node in this element's attribute map.
+ *
+ * @param   pcszMatch       The name of the attribute to find.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ */
+const AttributeNode *ElementNode::findAttribute(const char *pcszMatch, const char *pcszNamespace /*= NULL*/) const
+{
+    AttributeNode *p;
+    RTListForEachCpp(&m_attributes, p, AttributeNode, m_listEntry)
+    {
+        if (p->nameEqualsNS(pcszNamespace, pcszMatch))
+            return p;
+    }
+    return NULL;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a string.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   ppcsz           Where to return the attribute.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, const char **ppcsz, const char *pcszNamespace /*= NULL*/) const
+{
+    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
+    if (pAttr)
+    {
+        *ppcsz = pAttr->getValue();
+        return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a string.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   pStr            Pointer to the string object that should receive the
+ *                          attribute value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ *
+ * @throws  Whatever the string class may throw on assignment.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, RTCString *pStr, const char *pcszNamespace /*= NULL*/) const
+{
+    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
+    if (pAttr)
+    {
+        *pStr = pAttr->getValue();
+        return true;
+    }
+
+    return false;
+}
+
+/**
+ * Like getAttributeValue (ministring variant), but makes sure that all backslashes
+ * are converted to forward slashes.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   pStr            Pointer to the string object that should
+ *                          receive the attribute path value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValuePath(const char *pcszMatch, RTCString *pStr, const char *pcszNamespace /*= NULL*/) const
+{
+    if (getAttributeValue(pcszMatch, pStr, pcszNamespace))
+    {
+        pStr->findReplace('\\', '/');
+        return true;
+    }
+
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a signed 32-bit integer.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   piValue         Where to return the value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, int32_t *piValue, const char *pcszNamespace /*= NULL*/) const
+{
+    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
+    if (pcsz)
+    {
+        int rc = RTStrToInt32Ex(pcsz, NULL, 0, piValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as an unsigned 32-bit integer.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   puValue         Where to return the value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, uint32_t *puValue, const char *pcszNamespace /*= NULL*/) const
+{
+    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
+    if (pcsz)
+    {
+        int rc = RTStrToUInt32Ex(pcsz, NULL, 0, puValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a signed 64-bit integer.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   piValue         Where to return the value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, int64_t *piValue, const char *pcszNamespace /*= NULL*/) const
+{
+    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
+    if (pcsz)
+    {
+        int rc = RTStrToInt64Ex(pcsz, NULL, 0, piValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as an unsigned 64-bit integer.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   puValue         Where to return the value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, uint64_t *puValue, const char *pcszNamespace /*= NULL*/) const
+{
+    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
+    if (pcsz)
+    {
+        int rc = RTStrToUInt64Ex(pcsz, NULL, 0, puValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a boolean. This accepts "true", "false",
+ * "yes", "no", "1" or "0" as valid values.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   pfValue         Where to return the value.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValue(const char *pcszMatch, bool *pfValue, const char *pcszNamespace /*= NULL*/) const
+{
+    const char *pcsz = findAttributeValue(pcszMatch, pcszNamespace);
+    if (pcsz)
+    {
+        if (   !strcmp(pcsz, "true")
+            || !strcmp(pcsz, "yes")
+            || !strcmp(pcsz, "1")
+           )
+        {
+            *pfValue = true;
+            return true;
+        }
+        if (   !strcmp(pcsz, "false")
+            || !strcmp(pcsz, "no")
+            || !strcmp(pcsz, "0")
+           )
+        {
+            *pfValue = false;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a string.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   ppcsz           Where to return the attribute.
+ * @param   cchValueLimit   If the length of the returned value exceeds this
+ *                          limit a EIPRTFailure exception will be thrown.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValueN(const char *pcszMatch, const char **ppcsz, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
+{
+    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
+    if (pAttr)
+    {
+        *ppcsz = pAttr->getValueN(cchValueLimit);
+        return true;
+    }
+    return false;
+}
+
+/**
+ * Convenience method which attempts to find the attribute with the given
+ * name and returns its value as a string.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   pStr            Pointer to the string object that should receive the
+ *                          attribute value.
+ * @param   cchValueLimit   If the length of the returned value exceeds this
+ *                          limit a EIPRTFailure exception will be thrown.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ *
+ * @throws  Whatever the string class may throw on assignment.
+ */
+bool ElementNode::getAttributeValueN(const char *pcszMatch, RTCString *pStr, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
+{
+    const AttributeNode *pAttr = findAttribute(pcszMatch, pcszNamespace);
+    if (pAttr)
+    {
+        *pStr = pAttr->getValueN(cchValueLimit);
+        return true;
+    }
+
+    return false;
+}
+
+/**
+ * Like getAttributeValue (ministring variant), but makes sure that all backslashes
+ * are converted to forward slashes.
+ *
+ * @param   pcszMatch       Name of attribute to find.
+ * @param   pStr            Pointer to the string object that should
+ *                          receive the attribute path value.
+ * @param   cchValueLimit   If the length of the returned value exceeds this
+ *                          limit a EIPRTFailure exception will be thrown.
+ * @param   pcszNamespace   The attribute name space prefix or NULL.
+ * @returns Boolean success indicator.
+ */
+bool ElementNode::getAttributeValuePathN(const char *pcszMatch, RTCString *pStr, size_t cchValueLimit, const char *pcszNamespace /*= NULL*/) const
+{
+    if (getAttributeValueN(pcszMatch, pStr, cchValueLimit, pcszNamespace))
+    {
+        pStr->findReplace('\\', '/');
+        return true;
+    }
+
+    return false;
+}
+
+
+bool ElementNode::getElementValue(int32_t *piValue) const
+{
+    const char *pszValue = getValue();
+    if (pszValue)
+    {
+        int rc = RTStrToInt32Ex(pszValue, NULL, 0, piValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+bool ElementNode::getElementValue(uint32_t *puValue) const
+{
+    const char *pszValue = getValue();
+    if (pszValue)
+    {
+        int rc = RTStrToUInt32Ex(pszValue, NULL, 0, puValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+bool ElementNode::getElementValue(int64_t *piValue) const
+{
+    const char *pszValue = getValue();
+    if (pszValue)
+    {
+        int rc = RTStrToInt64Ex(pszValue, NULL, 0, piValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+bool ElementNode::getElementValue(uint64_t *puValue) const
+{
+    const char *pszValue = getValue();
+    if (pszValue)
+    {
+        int rc = RTStrToUInt64Ex(pszValue, NULL, 0, puValue);
+        if (rc == VINF_SUCCESS)
+            return true;
+    }
+    return false;
+}
+
+bool ElementNode::getElementValue(bool *pfValue) const
+{
+    const char *pszValue = getValue();
+    if (pszValue)
+    {
+        if (   !strcmp(pszValue, "true")
+            || !strcmp(pszValue, "yes")
+            || !strcmp(pszValue, "1")
+           )
+        {
+            *pfValue = true;
+            return true;
+        }
+        if (   !strcmp(pszValue, "false")
+            || !strcmp(pszValue, "no")
+            || !strcmp(pszValue, "0")
+           )
+        {
+            *pfValue = true;
+            return true;
+        }
+    }
+    return false;
+}
+
+
+/**
+ * Creates a new child element node and appends it to the list
+ * of children in "this".
+ *
+ * @param pcszElementName
+ * @return
+ */
+ElementNode *ElementNode::createChild(const char *pcszElementName)
+{
+    // we must be an element, not an attribute
+    if (!m_pLibNode)
+        throw ENodeIsNotElement(RT_SRC_POS);
+
+    // libxml side: create new node
+    xmlNode *pLibNode;
+    if (!(pLibNode = xmlNewNode(NULL,        // namespace
+                                (const xmlChar*)pcszElementName)))
+        throw std::bad_alloc();
+    xmlAddChild(m_pLibNode, pLibNode);
+
+    // now wrap this in C++
+    ElementNode *p = new ElementNode(m_pElmRoot, this, &m_children, pLibNode);
+    RTListAppend(&m_children, &p->m_listEntry);
+
+    return p;
+}
+
+
+/**
+ * Creates a content node and appends it to the list of children
+ * in "this".
+ *
+ * @param pcszContent
+ * @return
+ */
+ContentNode *ElementNode::addContent(const char *pcszContent)
+{
+    // libxml side: create new node
+    xmlNode *pLibNode = xmlNewText((const xmlChar*)pcszContent);
+    if (!pLibNode)
+        throw std::bad_alloc();
+    xmlAddChild(m_pLibNode, pLibNode);
+
+    // now wrap this in C++
+    ContentNode *p = new ContentNode(this, &m_children, pLibNode);
+    RTListAppend(&m_children, &p->m_listEntry);
+
+    return p;
+}
+
+/**
+ * Changes the contents of node and appends it to the list of
+ * children
+ *
+ * @param pcszContent
+ * @return
+ */
+ContentNode *ElementNode::setContent(const char *pcszContent)
+{
+//  1. Update content
+    xmlNodeSetContent(m_pLibNode, (const xmlChar*)pcszContent);
+
+//  2. Remove Content node from the list
+    /* Check that the order is right. */
+    xml::Node * pNode;
+    RTListForEachCpp(&m_children, pNode, xml::Node, m_listEntry)
+    {
+        bool fLast = RTListNodeIsLast(&m_children, &pNode->m_listEntry);
+
+        if (pNode->isContent())
+        {
+            RTListNodeRemove(&pNode->m_listEntry);
+        }
+
+        if (fLast)
+            break;
+    }
+
+//  3. Create a new node and append to the list
+    // now wrap this in C++
+    ContentNode *pCNode = new ContentNode(this, &m_children, m_pLibNode);
+    RTListAppend(&m_children, &pCNode->m_listEntry);
+
+    return pCNode;
+}
+
+/**
+ * Sets the given attribute; overloaded version for const char *.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param   pcszName        The attribute name.
+ * @param   pcszValue       The attribute value.
+ * @return  Pointer to the attribute node that was created or modified.
+ */
+AttributeNode *ElementNode::setAttribute(const char *pcszName, const char *pcszValue)
+{
+    /*
+     * Do we already have an attribute and should we just update it?
+     */
+    AttributeNode *pAttr;
+    RTListForEachCpp(&m_attributes, pAttr, AttributeNode, m_listEntry)
+    {
+        if (pAttr->nameEquals(pcszName))
+        {
+            /* Overwrite existing libxml attribute node ... */
+            xmlAttrPtr pLibAttr = xmlSetProp(m_pLibNode, (xmlChar *)pcszName, (xmlChar *)pcszValue);
+
+            /* ... and update our C++ wrapper in case the attrib pointer changed. */
+            pAttr->m_pLibAttr = pLibAttr;
+            return pAttr;
+        }
+    }
+
+    /*
+     * No existing attribute, create a new one.
+     */
+    /* libxml side: xmlNewProp creates an attribute. */
+    xmlAttr *pLibAttr = xmlNewProp(m_pLibNode, (xmlChar *)pcszName, (xmlChar *)pcszValue);
+
+    /* C++ side: Create an attribute node around it. */
+    pAttr = new AttributeNode(m_pElmRoot, this, &m_attributes, pLibAttr);
+    RTListAppend(&m_attributes, &pAttr->m_listEntry);
+
+    return pAttr;
+}
+
+/**
+ * Like setAttribute (ministring variant), but replaces all backslashes with forward slashes
+ * before calling that one.
+ * @param pcszName
+ * @param strValue
+ * @return
+ */
+AttributeNode* ElementNode::setAttributePath(const char *pcszName, const RTCString &strValue)
+{
+    RTCString strTemp(strValue);
+    strTemp.findReplace('\\', '/');
+    return setAttribute(pcszName, strTemp.c_str());
+}
+
+/**
+ * Sets the given attribute; overloaded version for int32_t.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param pcszName
+ * @param i
+ * @return
+ */
+AttributeNode* ElementNode::setAttribute(const char *pcszName, int32_t i)
+{
+    char szValue[12];  // negative sign + 10 digits + \0
+    RTStrPrintf(szValue, sizeof(szValue), "%RI32", i);
+    AttributeNode *p = setAttribute(pcszName, szValue);
+    return p;
+}
+
+/**
+ * Sets the given attribute; overloaded version for uint32_t.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param pcszName
+ * @param u
+ * @return
+ */
+AttributeNode* ElementNode::setAttribute(const char *pcszName, uint32_t u)
+{
+    char szValue[11];  // 10 digits + \0
+    RTStrPrintf(szValue, sizeof(szValue), "%RU32", u);
+    AttributeNode *p = setAttribute(pcszName, szValue);
+    return p;
+}
+
+/**
+ * Sets the given attribute; overloaded version for int64_t.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param pcszName
+ * @param i
+ * @return
+ */
+AttributeNode* ElementNode::setAttribute(const char *pcszName, int64_t i)
+{
+    char szValue[21];  // negative sign + 19 digits + \0
+    RTStrPrintf(szValue, sizeof(szValue), "%RI64", i);
+    AttributeNode *p = setAttribute(pcszName, szValue);
+    return p;
+}
+
+/**
+ * Sets the given attribute; overloaded version for uint64_t.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param pcszName
+ * @param u
+ * @return
+ */
+AttributeNode* ElementNode::setAttribute(const char *pcszName, uint64_t u)
+{
+    char szValue[21];  // 20 digits + \0
+    RTStrPrintf(szValue, sizeof(szValue), "%RU64", u);
+    AttributeNode *p = setAttribute(pcszName, szValue);
+    return p;
+}
+
+/**
+ * Sets the given attribute to the given uint32_t, outputs a hexadecimal string.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param pcszName
+ * @param u
+ * @return
+ */
+AttributeNode* ElementNode::setAttributeHex(const char *pcszName, uint32_t u)
+{
+    char szValue[11];  // "0x" + 8 digits + \0
+    RTStrPrintf(szValue, sizeof(szValue), "0x%RX32", u);
+    AttributeNode *p = setAttribute(pcszName, szValue);
+    return p;
+}
+
+/**
+ * Sets the given attribute; overloaded version for bool.
+ *
+ * If an attribute with the given name exists, it is overwritten,
+ * otherwise a new attribute is created. Returns the attribute node
+ * that was either created or changed.
+ *
+ * @param   pcszName    The attribute name.
+ * @param   f           The attribute value.
+ * @return
+ */
+AttributeNode* ElementNode::setAttribute(const char *pcszName, bool f)
+{
+    return setAttribute(pcszName, (f) ? "true" : "false");
+}
+
+/**
+ * Private constructor for a new attribute node.
+ *
+ * @param   pElmRoot    Pointer to the root element.  Needed for getting the
+ *                      default name space.
+ * @param   pParent     Pointer to the parent element (always an ElementNode,
+ *                      despite the type).  NULL for the root node.
+ * @param   pListAnchor Pointer to the m_children member of the parent.  NULL
+ *                      for the root node.
+ * @param   pLibAttr    Pointer to the libxml2 attribute structure.
+ */
+AttributeNode::AttributeNode(const ElementNode *pElmRoot,
+                             Node *pParent,
+                             PRTLISTANCHOR pListAnchor,
+                             xmlAttr *pLibAttr)
+    : Node(IsAttribute,
+           pParent,
+           pListAnchor,
+           NULL,
+           pLibAttr)
+{
+    m_pcszName = (const char *)pLibAttr->name;
+    RT_NOREF_PV(pElmRoot);
+
+    if (   pLibAttr->ns
+        && pLibAttr->ns->prefix)
+    {
+        m_pcszNamespacePrefix = (const char *)pLibAttr->ns->prefix;
+        m_pcszNamespaceHref   = (const char *)pLibAttr->ns->href;
+    }
+}
+
+ContentNode::ContentNode(Node *pParent, PRTLISTANCHOR pListAnchor, xmlNode *pLibNode)
+    : Node(IsContent,
+           pParent,
+           pListAnchor,
+           pLibNode,
+           NULL)
+{
+}
+
+/*
+ * NodesLoop
+ *
+ */
+
+struct NodesLoop::Data
+{
+    ElementNodesList listElements;
+    ElementNodesList::const_iterator it;
+};
+
+NodesLoop::NodesLoop(const ElementNode &node, const char *pcszMatch /* = NULL */)
+{
+    m = new Data;
+    node.getChildElements(m->listElements, pcszMatch);
+    m->it = m->listElements.begin();
+}
+
+NodesLoop::~NodesLoop()
+{
+    delete m;
+}
+
+
+/**
+ * Handy convenience helper for looping over all child elements. Create an
+ * instance of NodesLoop on the stack and call this method until it returns
+ * NULL, like this:
+ * <code>
+ *      xml::ElementNode node;               // should point to an element
+ *      xml::NodesLoop loop(node, "child");  // find all "child" elements under node
+ *      const xml::ElementNode *pChild = NULL;
+ *      while (pChild = loop.forAllNodes())
+ *          ...;
+ * </code>
+ * @return
+ */
+const ElementNode* NodesLoop::forAllNodes() const
+{
+    const ElementNode *pNode = NULL;
+
+    if (m->it != m->listElements.end())
+    {
+        pNode = *(m->it);
+        ++(m->it);
+    }
+
+    return pNode;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// Document class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+struct Document::Data
+{
+    xmlDocPtr   plibDocument;
+    ElementNode *pRootElement;
+    ElementNode *pComment;
+
+    Data()
+    {
+        plibDocument = NULL;
+        pRootElement = NULL;
+        pComment = NULL;
+    }
+
+    ~Data()
+    {
+        reset();
+    }
+
+    void reset()
+    {
+        if (plibDocument)
+        {
+            xmlFreeDoc(plibDocument);
+            plibDocument = NULL;
+        }
+        if (pRootElement)
+        {
+            delete pRootElement;
+            pRootElement = NULL;
+        }
+        if (pComment)
+        {
+            delete pComment;
+            pComment = NULL;
+        }
+    }
+
+    void copyFrom(const Document::Data *p)
+    {
+        if (p->plibDocument)
+        {
+            plibDocument = xmlCopyDoc(p->plibDocument,
+                                      1);      // recursive == copy all
+        }
+    }
+};
+
+Document::Document()
+    : m(new Data)
+{
+}
+
+Document::Document(const Document &x)
+    : m(new Data)
+{
+    m->copyFrom(x.m);
+}
+
+Document& Document::operator=(const Document &x)
+{
+    m->reset();
+    m->copyFrom(x.m);
+    return *this;
+}
+
+Document::~Document()
+{
+    delete m;
+}
+
+/**
+ * private method to refresh all internal structures after the internal pDocument
+ * has changed. Called from XmlFileParser::read(). m->reset() must have been
+ * called before to make sure all members except the internal pDocument are clean.
+ */
+void Document::refreshInternals() // private
+{
+    m->pRootElement = new ElementNode(NULL, NULL, NULL, xmlDocGetRootElement(m->plibDocument));
+
+    ElementNode::buildChildren(m->pRootElement);
+}
+
+/**
+ * Returns the root element of the document, or NULL if the document is empty.
+ * Const variant.
+ * @return
+ */
+const ElementNode *Document::getRootElement() const
+{
+    return m->pRootElement;
+}
+
+/**
+ * Returns the root element of the document, or NULL if the document is empty.
+ * Non-const variant.
+ * @return
+ */
+ElementNode *Document::getRootElement()
+{
+    return m->pRootElement;
+}
+
+/**
+ * Creates a new element node and sets it as the root element.
+ *
+ * This will only work if the document is empty; otherwise EDocumentNotEmpty is
+ * thrown.
+ */
+ElementNode *Document::createRootElement(const char *pcszRootElementName,
+                                         const char *pcszComment /* = NULL */)
+{
+    if (m->pRootElement || m->plibDocument)
+        throw EDocumentNotEmpty(RT_SRC_POS);
+
+    // libxml side: create document, create root node
+    m->plibDocument = xmlNewDoc((const xmlChar *)"1.0");
+    xmlNode *plibRootNode = xmlNewNode(NULL /*namespace*/ , (const xmlChar *)pcszRootElementName);
+    if (!plibRootNode)
+        throw std::bad_alloc();
+    xmlDocSetRootElement(m->plibDocument, plibRootNode);
+
+    // now wrap this in C++
+    m->pRootElement = new ElementNode(NULL, NULL, NULL, plibRootNode);
+
+    // add document global comment if specified
+    if (pcszComment != NULL)
+    {
+        xmlNode *pComment = xmlNewDocComment(m->plibDocument, (const xmlChar *)pcszComment);
+        if (!pComment)
+            throw std::bad_alloc();
+        xmlAddPrevSibling(plibRootNode, pComment);
+
+        // now wrap this in C++
+        m->pComment = new ElementNode(NULL, NULL, NULL, pComment);
+    }
+
+    return m->pRootElement;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlParserBase class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+static void xmlParserBaseGenericError(void *pCtx, const char *pszMsg, ...) RT_NOTHROW_DEF
+{
+    NOREF(pCtx);
+    va_list args;
+    va_start(args, pszMsg);
+    RTLogRelPrintfV(pszMsg, args);
+    va_end(args);
+}
+
+static void xmlParserBaseStructuredError(void *pCtx, xmlErrorPtr error) RT_NOTHROW_DEF
+{
+    NOREF(pCtx);
+    /* we expect that there is always a trailing NL */
+    LogRel(("XML error at '%s' line %d: %s", error->file, error->line, error->message));
+}
+
+XmlParserBase::XmlParserBase()
+{
+    m_ctxt = xmlNewParserCtxt();
+    if (m_ctxt == NULL)
+        throw std::bad_alloc();
+    /* per-thread so it must be here */
+    xmlSetGenericErrorFunc(NULL, xmlParserBaseGenericError);
+    xmlSetStructuredErrorFunc(NULL, xmlParserBaseStructuredError);
+}
+
+XmlParserBase::~XmlParserBase()
+{
+    xmlSetStructuredErrorFunc(NULL, NULL);
+    xmlSetGenericErrorFunc(NULL, NULL);
+    xmlFreeParserCtxt (m_ctxt);
+    m_ctxt = NULL;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlMemParser class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+XmlMemParser::XmlMemParser()
+    : XmlParserBase()
+{
+}
+
+XmlMemParser::~XmlMemParser()
+{
+}
+
+/**
+ * Parse the given buffer and fills the given Document object with its contents.
+ * Throws XmlError on parsing errors.
+ *
+ * The document that is passed in will be reset before being filled if not empty.
+ *
+ * @param pvBuf         Memory buffer to parse.
+ * @param cbSize        Size of the memory buffer.
+ * @param strFilename   Refernece to the name of the file we're parsing.
+ * @param doc           Reference to the output document.  This will be reset
+ *                      and filled with data according to file contents.
+ */
+void XmlMemParser::read(const void *pvBuf, size_t cbSize,
+                        const RTCString &strFilename,
+                        Document &doc)
+{
+    GlobalLock lock;
+//     global.setExternalEntityLoader(ExternalEntityLoader);
+
+    const char *pcszFilename = strFilename.c_str();
+
+    doc.m->reset();
+    const int options = XML_PARSE_NOBLANKS /* remove blank nodes */
+                      | XML_PARSE_NONET    /* forbit any network access */
+#if LIBXML_VERSION >= 20700
+                      | XML_PARSE_HUGE     /* don't restrict the node depth
+                                              to 256 (bad for snapshots!) */
+#endif
+                ;
+    if (!(doc.m->plibDocument = xmlCtxtReadMemory(m_ctxt,
+                                                  (const char*)pvBuf,
+                                                  (int)cbSize,
+                                                  pcszFilename,
+                                                  NULL,       // encoding = auto
+                                                  options)))
+        throw XmlError(xmlCtxtGetLastError(m_ctxt));
+
+    doc.refreshInternals();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlMemWriter class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+XmlMemWriter::XmlMemWriter()
+  : m_pBuf(0)
+{
+}
+
+XmlMemWriter::~XmlMemWriter()
+{
+    if (m_pBuf)
+        xmlFree(m_pBuf);
+}
+
+void XmlMemWriter::write(const Document &doc, void **ppvBuf, size_t *pcbSize)
+{
+    if (m_pBuf)
+    {
+        xmlFree(m_pBuf);
+        m_pBuf = 0;
+    }
+    int size;
+    xmlDocDumpFormatMemory(doc.m->plibDocument, (xmlChar**)&m_pBuf, &size, 1);
+    *ppvBuf = m_pBuf;
+    *pcbSize = size;
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlStringWriter class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+XmlStringWriter::XmlStringWriter()
+  : m_pStrDst(NULL), m_fOutOfMemory(false)
+{
+}
+
+int XmlStringWriter::write(const Document &rDoc, RTCString *pStrDst)
+{
+    /*
+     * Clear the output string and take the global libxml2 lock so we can
+     * safely configure the output formatting.
+     */
+    pStrDst->setNull();
+
+    GlobalLock lock;
+
+    xmlIndentTreeOutput = 1;
+    xmlTreeIndentString = "  ";
+    xmlSaveNoEmptyTags  = 0;
+
+    /*
+     * Do a pass to calculate the size.
+     */
+    size_t cbOutput = 1; /* zero term */
+
+    xmlSaveCtxtPtr pSaveCtx= xmlSaveToIO(WriteCallbackForSize, CloseCallback, &cbOutput, NULL /*pszEncoding*/, XML_SAVE_FORMAT);
+    if (!pSaveCtx)
+        return VERR_NO_MEMORY;
+
+    long rcXml = xmlSaveDoc(pSaveCtx, rDoc.m->plibDocument);
+    xmlSaveClose(pSaveCtx);
+    if (rcXml == -1)
+        return VERR_GENERAL_FAILURE;
+
+    /*
+     * Try resize the string.
+     */
+    int rc = pStrDst->reserveNoThrow(cbOutput);
+    if (RT_SUCCESS(rc))
+    {
+        /*
+         * Do the real run where we feed output to the string.
+         */
+        m_pStrDst      = pStrDst;
+        m_fOutOfMemory = false;
+        pSaveCtx = xmlSaveToIO(WriteCallbackForReal, CloseCallback, this, NULL /*pszEncoding*/, XML_SAVE_FORMAT);
+        if (pSaveCtx)
+        {
+            rcXml = xmlSaveDoc(pSaveCtx, rDoc.m->plibDocument);
+            xmlSaveClose(pSaveCtx);
+            m_pStrDst = NULL;
+            if (rcXml != -1)
+            {
+                if (!m_fOutOfMemory)
+                    return VINF_SUCCESS;
+
+                rc = VERR_NO_STR_MEMORY;
+            }
+            else
+                rc = VERR_GENERAL_FAILURE;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+        pStrDst->setNull();
+        m_pStrDst = NULL;
+    }
+    return rc;
+}
+
+/*static*/ int XmlStringWriter::WriteCallbackForSize(void *pvUser, const char *pachBuf, int cbToWrite) RT_NOTHROW_DEF
+{
+    if (cbToWrite > 0)
+        *(size_t *)pvUser += (unsigned)cbToWrite;
+    RT_NOREF(pachBuf);
+    return cbToWrite;
+}
+
+/*static*/ int XmlStringWriter::WriteCallbackForReal(void *pvUser, const char *pachBuf, int cbToWrite) RT_NOTHROW_DEF
+{
+    XmlStringWriter *pThis = static_cast<XmlStringWriter*>(pvUser);
+    if (!pThis->m_fOutOfMemory)
+    {
+        if (cbToWrite > 0)
+        {
+            try
+            {
+                pThis->m_pStrDst->append(pachBuf, (size_t)cbToWrite);
+            }
+            catch (std::bad_alloc &)
+            {
+                pThis->m_fOutOfMemory = true;
+                return -1;
+            }
+        }
+        return cbToWrite;
+    }
+    return -1; /* failure */
+}
+
+/*static*/ int XmlStringWriter::CloseCallback(void *pvUser) RT_NOTHROW_DEF
+{
+    /* Nothing to do here. */
+    RT_NOREF(pvUser);
+    return 0;
+}
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlFileParser class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+struct XmlFileParser::Data
+{
+    RTCString strXmlFilename;
+
+    Data()
+    {
+    }
+
+    ~Data()
+    {
+    }
+};
+
+XmlFileParser::XmlFileParser()
+    : XmlParserBase(),
+      m(new Data())
+{
+}
+
+XmlFileParser::~XmlFileParser()
+{
+    delete m;
+    m = NULL;
+}
+
+struct IOContext
+{
+    File file;
+    RTCString error;
+
+    IOContext(const char *pcszFilename, File::Mode mode, bool fFlush = false)
+        : file(mode, pcszFilename, fFlush)
+    {
+    }
+
+    void setError(const RTCError &x)
+    {
+        error = x.what();
+    }
+
+    void setError(const std::exception &x)
+    {
+        error = x.what();
+    }
+
+private:
+    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(IOContext); /* (shuts up C4626 and C4625 MSC warnings) */
+};
+
+struct ReadContext : IOContext
+{
+    ReadContext(const char *pcszFilename)
+        : IOContext(pcszFilename, File::Mode_Read)
+    {
+    }
+
+private:
+    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(ReadContext); /* (shuts up C4626 and C4625 MSC warnings) */
+};
+
+struct WriteContext : IOContext
+{
+    WriteContext(const char *pcszFilename, bool fFlush)
+        : IOContext(pcszFilename, File::Mode_Overwrite, fFlush)
+    {
+    }
+
+private:
+    DECLARE_CLS_COPY_CTOR_ASSIGN_NOOP(WriteContext); /* (shuts up C4626 and C4625 MSC warnings) */
+};
+
+/**
+ * Reads the given file and fills the given Document object with its contents.
+ * Throws XmlError on parsing errors.
+ *
+ * The document that is passed in will be reset before being filled if not empty.
+ *
+ * @param strFilename in: name fo file to parse.
+ * @param doc out: document to be reset and filled with data according to file contents.
+ */
+void XmlFileParser::read(const RTCString &strFilename,
+                         Document &doc)
+{
+    GlobalLock lock;
+//     global.setExternalEntityLoader(ExternalEntityLoader);
+
+    m->strXmlFilename = strFilename;
+    const char *pcszFilename = strFilename.c_str();
+
+    ReadContext context(pcszFilename);
+    doc.m->reset();
+    const int options = XML_PARSE_NOBLANKS /* remove blank nodes */
+                      | XML_PARSE_NONET    /* forbit any network access */
+#if LIBXML_VERSION >= 20700
+                      | XML_PARSE_HUGE     /* don't restrict the node depth
+                                              to 256 (bad for snapshots!) */
+#endif
+                ;
+    if (!(doc.m->plibDocument = xmlCtxtReadIO(m_ctxt,
+                                              ReadCallback,
+                                              CloseCallback,
+                                              &context,
+                                              pcszFilename,
+                                              NULL,       // encoding = auto
+                                              options)))
+        throw XmlError(xmlCtxtGetLastError(m_ctxt));
+
+    doc.refreshInternals();
+}
+
+/*static*/ int XmlFileParser::ReadCallback(void *aCtxt, char *aBuf, int aLen) RT_NOTHROW_DEF
+{
+    ReadContext *pContext = static_cast<ReadContext*>(aCtxt);
+
+    /* To prevent throwing exceptions while inside libxml2 code, we catch
+     * them and forward to our level using a couple of variables. */
+
+    try
+    {
+        return pContext->file.read(aBuf, aLen);
+    }
+    catch (const xml::EIPRTFailure &err) { pContext->setError(err); }
+    catch (const RTCError &err) { pContext->setError(err); }
+    catch (const std::exception &err) { pContext->setError(err); }
+    catch (...) { pContext->setError(xml::LogicError(RT_SRC_POS)); }
+
+    return -1 /* failure */;
+}
+
+/*static*/ int XmlFileParser::CloseCallback(void *aCtxt) RT_NOTHROW_DEF
+{
+    /// @todo to be written
+    NOREF(aCtxt);
+
+    return -1;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// XmlFileWriter class
+//
+////////////////////////////////////////////////////////////////////////////////
+
+struct XmlFileWriter::Data
+{
+    Document *pDoc;
+};
+
+XmlFileWriter::XmlFileWriter(Document &doc)
+{
+    m = new Data();
+    m->pDoc = &doc;
+}
+
+XmlFileWriter::~XmlFileWriter()
+{
+    delete m;
+}
+
+void XmlFileWriter::writeInternal(const char *pcszFilename, bool fSafe)
+{
+    WriteContext context(pcszFilename, fSafe);
+
+    GlobalLock lock;
+
+    /* serialize to the stream */
+    xmlIndentTreeOutput = 1;
+    xmlTreeIndentString = "  ";
+    xmlSaveNoEmptyTags = 0;
+
+    xmlSaveCtxtPtr saveCtxt;
+    if (!(saveCtxt = xmlSaveToIO(WriteCallback,
+                                 CloseCallback,
+                                 &context,
+                                 NULL,
+                                 XML_SAVE_FORMAT)))
+        throw xml::LogicError(RT_SRC_POS);
+
+    long rc = xmlSaveDoc(saveCtxt, m->pDoc->m->plibDocument);
+    if (rc == -1)
+    {
+        /* look if there was a forwarded exception from the lower level */
+//         if (m->trappedErr.get() != NULL)
+//             m->trappedErr->rethrow();
+
+        /* there must be an exception from the Output implementation,
+         * otherwise the save operation must always succeed. */
+        throw xml::LogicError(RT_SRC_POS);
+    }
+
+    xmlSaveClose(saveCtxt);
+}
+
+void XmlFileWriter::write(const char *pcszFilename, bool fSafe)
+{
+    if (!fSafe)
+        writeInternal(pcszFilename, fSafe);
+    else
+    {
+        /* Empty string and directory spec must be avoid. */
+        if (RTPathFilename(pcszFilename) == NULL)
+            throw xml::LogicError(RT_SRC_POS);
+
+        /* Construct both filenames first to ease error handling.  */
+        char szTmpFilename[RTPATH_MAX];
+        int rc = RTStrCopy(szTmpFilename, sizeof(szTmpFilename) - strlen(s_pszTmpSuff), pcszFilename);
+        if (RT_FAILURE(rc))
+            throw EIPRTFailure(rc, "RTStrCopy");
+        strcat(szTmpFilename, s_pszTmpSuff);
+
+        char szPrevFilename[RTPATH_MAX];
+        rc = RTStrCopy(szPrevFilename, sizeof(szPrevFilename) - strlen(s_pszPrevSuff), pcszFilename);
+        if (RT_FAILURE(rc))
+            throw EIPRTFailure(rc, "RTStrCopy");
+        strcat(szPrevFilename, s_pszPrevSuff);
+
+        /* Write the XML document to the temporary file.  */
+        writeInternal(szTmpFilename, fSafe);
+
+        /* Make a backup of any existing file (ignore failure). */
+        uint64_t cbPrevFile;
+        rc = RTFileQuerySizeByPath(pcszFilename, &cbPrevFile);
+        if (RT_SUCCESS(rc) && cbPrevFile >= 16)
+            RTFileRename(pcszFilename, szPrevFilename, RTPATHRENAME_FLAGS_REPLACE);
+
+        /* Commit the temporary file. Just leave the tmp file behind on failure. */
+        rc = RTFileRename(szTmpFilename, pcszFilename, RTPATHRENAME_FLAGS_REPLACE);
+        if (RT_FAILURE(rc))
+            throw EIPRTFailure(rc, "Failed to replace '%s' with '%s'", pcszFilename, szTmpFilename);
+
+        /* Flush the directory changes (required on linux at least). */
+        RTPathStripFilename(szTmpFilename);
+        rc = RTDirFlush(szTmpFilename);
+        AssertMsg(RT_SUCCESS(rc) || rc == VERR_NOT_SUPPORTED || rc == VERR_NOT_IMPLEMENTED, ("%Rrc\n", rc));
+    }
+}
+
+/*static*/ int XmlFileWriter::WriteCallback(void *aCtxt, const char *aBuf, int aLen) RT_NOTHROW_DEF
+{
+    WriteContext *pContext = static_cast<WriteContext*>(aCtxt);
+
+    /* To prevent throwing exceptions while inside libxml2 code, we catch
+     * them and forward to our level using a couple of variables. */
+    try
+    {
+        return pContext->file.write(aBuf, aLen);
+    }
+    catch (const xml::EIPRTFailure &err) { pContext->setError(err); }
+    catch (const RTCError &err) { pContext->setError(err); }
+    catch (const std::exception &err) { pContext->setError(err); }
+    catch (...) { pContext->setError(xml::LogicError(RT_SRC_POS)); }
+
+    return -1 /* failure */;
+}
+
+/*static*/ int XmlFileWriter::CloseCallback(void *aCtxt) RT_NOTHROW_DEF
+{
+    /// @todo to be written
+    NOREF(aCtxt);
+
+    return -1;
+}
+
+/*static*/ const char * const XmlFileWriter::s_pszTmpSuff  = "-tmp";
+/*static*/ const char * const XmlFileWriter::s_pszPrevSuff = "-prev";
+
+
+} // end namespace xml
+