Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

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

1 files changed, 1645 insertions, 0 deletions

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..e4ce5274
--- /dev/null
+++ b/src/VBox/Runtime/r3/win/localipc-win.cpp
@@ -0,0 +1,1645 @@
+/* $Id: localipc-win.cpp $ */
+/** @file
+ * IPRT - Local IPC, Windows Implementation Using Named Pipes.
+ */
+
+/*
+ * Copyright (C) 2008-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_LOCALIPC
+/*
+ * We have to force NT 5.0 here because of
+ * ConvertStringSecurityDescriptorToSecurityDescriptor. Note that because of
+ * FILE_FLAG_FIRST_PIPE_INSTANCE this code actually requires W2K SP2+.
+ */
+#ifndef _WIN32_WINNT
+# define _WIN32_WINNT 0x0500 /* for ConvertStringSecurityDescriptorToSecurityDescriptor */
+#elif _WIN32_WINNT < 0x0500
+# undef _WIN32_WINNT
+# define _WIN32_WINNT 0x0500
+#endif
+#define UNICODE    /* For the SDDL_ strings. */
+#include <iprt/win/windows.h>
+#include <sddl.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-"
+
+/** 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
+
+//        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" SDDL_GENERIC_ALL L";;;" SDDL_PERSONAL_SELF SDDL_ACE_END \
+//        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";CIOI;" SDDL_GENERIC_ALL L";;;" SDDL_CREATOR_OWNER SDDL_ACE_END
+//        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" L"0x0012019b"    L";;;" SDDL_EVERYONE SDDL_ACE_END
+//        SDDL_ACE_BEGIN SDDL_ACCESS_ALLOWED L";;" SDDL_FILE_ALL L";;;" SDDL_LOCAL_SYSTEM SDDL_ACE_END
+
+
+/*********************************************************************************************************************************
+*   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);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+static bool volatile g_fResolvedApis = false;
+/** advapi32.dll API ConvertStringSecurityDescriptorToSecurityDescriptorW. */
+static decltype(ConvertStringSecurityDescriptorToSecurityDescriptorW) *g_pfnSSDLToSecDescW = NULL;
+
+
+/**
+ * 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 rtLocalIpcServerWinAllocSecurityDescriptior(PSECURITY_DESCRIPTOR *ppDesc, bool fServer)
+{
+    /*
+     * Resolve the API the first time around.
+     */
+    if (!g_fResolvedApis)
+    {
+        g_pfnSSDLToSecDescW = (decltype(g_pfnSSDLToSecDescW))RTLdrGetSystemSymbol("advapi32.dll", "ConvertStringSecurityDescriptorToSecurityDescriptorW");
+        ASMCompilerBarrier();
+        g_fResolvedApis = true;
+    }
+
+    int rc;
+    PSECURITY_DESCRIPTOR pSecDesc = NULL;
+    if (g_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;
+        if (g_pfnSSDLToSecDescW(pwszSDDL, SDDL_REVISION_1, &pSecDesc, NULL))
+        {
+            AssertPtr(pSecDesc);
+            *ppDesc = pSecDesc;
+            return VINF_SUCCESS;
+        }
+
+        rc = RTErrConvertFromWin32(GetLastError());
+    }
+    else
+    {
+        /* Windows OSes < W2K SP2 not supported for now, bail out. */
+        /** @todo Implement me! */
+        rc = VERR_NOT_SUPPORTED;
+    }
+    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;
+
+    PSECURITY_DESCRIPTOR pSecDesc;
+    int rc = rtLocalIpcServerWinAllocSecurityDescriptior(&pSecDesc, fFirst /* Server? */);
+    if (RT_SUCCESS(rc))
+    {
+        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 */
+        LocalFree(pSecDesc);
+        if (hNmPipe != INVALID_HANDLE_VALUE)
+            *phNmPipe = hNmPipe;
+        else
+            rc = RTErrConvertFromWin32(GetLastError());
+    }
+
+    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.
+ *
+ * @returns
+ * @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) 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)
+                fRc = CancelIo(pThis->hNmPipe);
+            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 = rtLocalIpcServerWinAllocSecurityDescriptior(&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;
+
+                    HANDLE hPipe = CreateFileW(pwszFullName,
+                                               GENERIC_READ | GENERIC_WRITE,
+                                               0 /*no sharing*/,
+                                               &SecAttrs,
+                                               OPEN_EXISTING,
+                                               FILE_FLAG_OVERLAPPED,
+                                               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 CancelIo since this call cancels both read and write oriented operations.
+     */
+    if (   pThis->fZeroByteRead
+        || pThis->Read.hActiveThread != NIL_RTTHREAD
+        || pThis->Write.hActiveThread != NIL_RTTHREAD)
+        CancelIo(pThis->hNmPipe);
+
+    /*
+     * 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
+ * CancelIo 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;
+}
+