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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
commitf215e02bf85f68d3a6106c2a1f4f7f063f819064 (patch)
tree6bb5b92c046312c4e95ac2620b10ddf482d3fa8b /src/VBox/Runtime/generic/semrw-generic.cpp
parentInitial commit. (diff)
downloadvirtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.tar.xz
virtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.zip
Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/VBox/Runtime/generic/semrw-generic.cpp')
-rw-r--r--src/VBox/Runtime/generic/semrw-generic.cpp988
1 files changed, 988 insertions, 0 deletions
diff --git a/src/VBox/Runtime/generic/semrw-generic.cpp b/src/VBox/Runtime/generic/semrw-generic.cpp
new file mode 100644
index 00000000..3cde84bf
--- /dev/null
+++ b/src/VBox/Runtime/generic/semrw-generic.cpp
@@ -0,0 +1,988 @@
+/* $Id: semrw-generic.cpp $ */
+/** @file
+ * IPRT - Read-Write Semaphore, Generic.
+ *
+ * This is a generic implementation for OSes which don't have
+ * native RW semaphores.
+ */
+
+/*
+ * 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 RTSEMRW_WITHOUT_REMAPPING
+#include <iprt/semaphore.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/critsect.h>
+#include <iprt/err.h>
+#include <iprt/lockvalidator.h>
+#include <iprt/mem.h>
+#include <iprt/time.h>
+#include <iprt/thread.h>
+
+#include "internal/magics.h"
+#include "internal/strict.h"
+
+
+/*********************************************************************************************************************************
+* Structures and Typedefs *
+*********************************************************************************************************************************/
+
+/** Internal representation of a Read-Write semaphore for the
+ * Generic implementation. */
+struct RTSEMRWINTERNAL
+{
+ /** The usual magic. (RTSEMRW_MAGIC) */
+ uint32_t u32Magic;
+ /* Alignment padding. */
+ uint32_t u32Padding;
+ /** This critical section serializes the access to and updating of the structure members. */
+ RTCRITSECT CritSect;
+ /** The current number of reads. (pure read recursion counts too) */
+ uint32_t cReads;
+ /** The current number of writes. (recursion counts too) */
+ uint32_t cWrites;
+ /** Number of read recursions by the writer. */
+ uint32_t cWriterReads;
+ /** Number of writers waiting. */
+ uint32_t cWritesWaiting;
+ /** The write owner of the lock. */
+ RTNATIVETHREAD hWriter;
+ /** The handle of the event object on which the waiting readers block. (manual reset). */
+ RTSEMEVENTMULTI ReadEvent;
+ /** The handle of the event object on which the waiting writers block. (automatic reset). */
+ RTSEMEVENT WriteEvent;
+ /** Need to reset ReadEvent. */
+ bool fNeedResetReadEvent;
+#ifdef RTSEMRW_STRICT
+ /** The validator record for the writer. */
+ RTLOCKVALRECEXCL ValidatorWrite;
+ /** The validator record for the readers. */
+ RTLOCKVALRECSHRD ValidatorRead;
+#endif
+};
+
+
+
+RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem)
+{
+ return RTSemRWCreateEx(phRWSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, "RTSemRW");
+}
+RT_EXPORT_SYMBOL(RTSemRWCreate);
+
+
+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 memory.
+ */
+ int rc;
+ struct RTSEMRWINTERNAL *pThis = (struct RTSEMRWINTERNAL *)RTMemAlloc(sizeof(struct RTSEMRWINTERNAL));
+ if (pThis)
+ {
+ /*
+ * Create the semaphores.
+ */
+ rc = RTSemEventCreateEx(&pThis->WriteEvent, RTSEMEVENT_FLAGS_NO_LOCK_VAL, NIL_RTLOCKVALCLASS, NULL);
+ if (RT_SUCCESS(rc))
+ {
+ rc = RTSemEventMultiCreateEx(&pThis->ReadEvent, RTSEMEVENT_FLAGS_NO_LOCK_VAL, NIL_RTLOCKVALCLASS, NULL);
+ if (RT_SUCCESS(rc))
+ {
+ rc = RTCritSectInitEx(&pThis->CritSect, RTCRITSECT_FLAGS_NO_LOCK_VAL,
+ NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL);
+ if (RT_SUCCESS(rc))
+ {
+ /*
+ * Signal the read semaphore and initialize other variables.
+ */
+ rc = RTSemEventMultiSignal(pThis->ReadEvent);
+ if (RT_SUCCESS(rc))
+ {
+ pThis->u32Padding = UINT32_C(0xa5a55a5a);
+ pThis->cReads = 0;
+ pThis->cWrites = 0;
+ pThis->cWriterReads = 0;
+ pThis->cWritesWaiting = 0;
+ pThis->hWriter = NIL_RTNATIVETHREAD;
+ pThis->fNeedResetReadEvent = true;
+ pThis->u32Magic = RTSEMRW_MAGIC;
+#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;
+ }
+ RTCritSectDelete(&pThis->CritSect);
+ }
+ RTSemEventMultiDestroy(pThis->ReadEvent);
+ }
+ RTSemEventDestroy(pThis->WriteEvent);
+ }
+ RTMemFree(pThis);
+ }
+ else
+ rc = VERR_NO_MEMORY;
+
+ return rc;
+}
+RT_EXPORT_SYMBOL(RTSemRWCreate);
+
+
+RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem)
+{
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+
+ /*
+ * Validate handle.
+ */
+ if (pThis == NIL_RTSEMRW)
+ return VINF_SUCCESS;
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
+
+ /*
+ * Check if busy.
+ */
+ int rc = RTCritSectTryEnter(&pThis->CritSect);
+ if (RT_SUCCESS(rc))
+ {
+ if (!pThis->cReads && !pThis->cWrites)
+ {
+ /*
+ * Make it invalid and unusable.
+ */
+ ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMRW_MAGIC);
+ pThis->cReads = UINT32_MAX;
+
+ /*
+ * Do actual cleanup. None of these can now fail.
+ */
+ rc = RTSemEventMultiDestroy(pThis->ReadEvent);
+ AssertMsgRC(rc, ("RTSemEventMultiDestroy failed! rc=%Rrc\n", rc));
+ pThis->ReadEvent = NIL_RTSEMEVENTMULTI;
+
+ rc = RTSemEventDestroy(pThis->WriteEvent);
+ AssertMsgRC(rc, ("RTSemEventDestroy failed! rc=%Rrc\n", rc));
+ pThis->WriteEvent = NIL_RTSEMEVENT;
+
+ RTCritSectLeave(&pThis->CritSect);
+ rc = RTCritSectDelete(&pThis->CritSect);
+ AssertMsgRC(rc, ("RTCritSectDelete failed! rc=%Rrc\n", rc));
+
+#ifdef RTSEMRW_STRICT
+ RTLockValidatorRecSharedDelete(&pThis->ValidatorRead);
+ RTLockValidatorRecExclDelete(&pThis->ValidatorWrite);
+#endif
+ RTMemFree(pThis);
+ rc = VINF_SUCCESS;
+ }
+ else
+ {
+ rc = VERR_SEM_BUSY;
+ RTCritSectLeave(&pThis->CritSect);
+ }
+ }
+ else
+ {
+ AssertMsgRC(rc, ("RTCritSectTryEnter failed! rc=%Rrc\n", rc));
+ rc = VERR_SEM_BUSY;
+ }
+
+ return rc;
+}
+RT_EXPORT_SYMBOL(RTSemRWDestroy);
+
+
+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
+}
+RT_EXPORT_SYMBOL(RTSemRWSetSubClass);
+
+
+DECL_FORCE_INLINE(int) rtSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
+{
+ /*
+ * Validate handle.
+ */
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
+
+ RTMSINTERVAL cMilliesInitial = cMillies;
+ uint64_t tsStart = 0;
+ if (cMillies != RT_INDEFINITE_WAIT && cMillies != 0)
+ tsStart = RTTimeNanoTS();
+
+#ifdef RTSEMRW_STRICT
+ RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
+ if (cMillies > 0)
+ {
+ int rc9;
+ if (pThis->hWriter != NIL_RTTHREAD && pThis->hWriter == RTThreadNativeSelf())
+ rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
+ else
+ rc9 = RTLockValidatorRecSharedCheckOrder(&pThis->ValidatorRead, hThreadSelf, pSrcPos, cMillies);
+ if (RT_FAILURE(rc9))
+ return rc9;
+ }
+#endif
+
+ /*
+ * Take critsect.
+ */
+ int rc = RTCritSectEnter(&pThis->CritSect);
+ if (RT_FAILURE(rc))
+ {
+ AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ return rc;
+ }
+
+ /*
+ * Check if the state of affairs allows read access.
+ * Do not block further readers if there is a writer waiting, as
+ * that will break/deadlock reader recursion.
+ */
+ if ( pThis->hWriter == NIL_RTNATIVETHREAD
+#if 0
+ && ( !pThis->cWritesWaiting
+ || pThis->cReads)
+#endif
+ )
+ {
+ pThis->cReads++;
+ Assert(pThis->cReads > 0);
+#ifdef RTSEMRW_STRICT
+ RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
+#endif
+
+ RTCritSectLeave(&pThis->CritSect);
+ return VINF_SUCCESS;
+ }
+
+ RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
+ if (pThis->hWriter == hNativeSelf)
+ {
+#ifdef RTSEMRW_STRICT
+ int rc9 = RTLockValidatorRecExclRecursionMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core, pSrcPos);
+ if (RT_FAILURE(rc9))
+ {
+ RTCritSectLeave(&pThis->CritSect);
+ return rc9;
+ }
+#endif
+
+ pThis->cWriterReads++;
+ Assert(pThis->cWriterReads > 0);
+
+ RTCritSectLeave(&pThis->CritSect);
+ return VINF_SUCCESS;
+ }
+
+ RTCritSectLeave(&pThis->CritSect);
+
+ /*
+ * Wait till it's ready for reading.
+ */
+ if (cMillies == 0)
+ return VERR_TIMEOUT;
+
+#ifndef RTSEMRW_STRICT
+ RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+ for (;;)
+ {
+ if (cMillies != RT_INDEFINITE_WAIT)
+ {
+ int64_t tsDelta = RTTimeNanoTS() - tsStart;
+ if (tsDelta >= 1000000)
+ {
+ tsDelta /= 1000000;
+ if ((uint64_t)tsDelta < cMilliesInitial)
+ cMilliesInitial = (RTMSINTERVAL)tsDelta;
+ else
+ cMilliesInitial = 1;
+ }
+ }
+#ifdef RTSEMRW_STRICT
+ rc = RTLockValidatorRecSharedCheckBlocking(&pThis->ValidatorRead, hThreadSelf, pSrcPos, true,
+ cMillies, RTTHREADSTATE_RW_READ, false);
+ if (RT_FAILURE(rc))
+ break;
+#else
+ RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_READ, false);
+ RT_NOREF_PV(pSrcPos);
+#endif
+ int rcWait;
+ if (fInterruptible)
+ rcWait = rc = RTSemEventMultiWaitNoResume(pThis->ReadEvent, cMillies);
+ else
+ rcWait = rc = RTSemEventMultiWait(pThis->ReadEvent, cMillies);
+ RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_READ);
+ if (RT_FAILURE(rc) && rc != VERR_TIMEOUT) /* handle timeout below */
+ {
+ AssertMsgRC(rc, ("RTSemEventMultiWait failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ break;
+ }
+
+ if (pThis->u32Magic != RTSEMRW_MAGIC)
+ {
+ rc = VERR_SEM_DESTROYED;
+ break;
+ }
+
+ /*
+ * Re-take critsect and repeat the check we did before the loop.
+ */
+ rc = RTCritSectEnter(&pThis->CritSect);
+ if (RT_FAILURE(rc))
+ {
+ AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ break;
+ }
+
+ if ( pThis->hWriter == NIL_RTNATIVETHREAD
+#if 0
+ && ( !pThis->cWritesWaiting
+ || pThis->cReads)
+#endif
+ )
+ {
+ pThis->cReads++;
+ Assert(pThis->cReads > 0);
+#ifdef RTSEMRW_STRICT
+ RTLockValidatorRecSharedAddOwner(&pThis->ValidatorRead, hThreadSelf, pSrcPos);
+#endif
+
+ RTCritSectLeave(&pThis->CritSect);
+ return VINF_SUCCESS;
+ }
+
+ RTCritSectLeave(&pThis->CritSect);
+
+ /*
+ * Quit if the wait already timed out.
+ */
+ if (rcWait == VERR_TIMEOUT)
+ {
+ rc = VERR_TIMEOUT;
+ break;
+ }
+ }
+
+ /* failed */
+ return rc;
+}
+
+
+RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+ return rtSemRWRequestRead(hRWSem, cMillies, false, NULL);
+#else
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+ return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestRead);
+
+
+RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+ return rtSemRWRequestRead(hRWSem, cMillies, false, &SrcPos);
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestReadDebug);
+
+
+RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+ return rtSemRWRequestRead(hRWSem, cMillies, true, NULL);
+#else
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+ return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResume);
+
+
+RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+ return rtSemRWRequestRead(hRWSem, cMillies, true, &SrcPos);
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestReadNoResumeDebug);
+
+
+RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem)
+{
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+
+ /*
+ * Validate handle.
+ */
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
+
+ /*
+ * Take critsect.
+ */
+ int rc = RTCritSectEnter(&pThis->CritSect);
+ if (RT_SUCCESS(rc))
+ {
+ if (pThis->hWriter == NIL_RTNATIVETHREAD)
+ {
+#ifdef RTSEMRW_STRICT
+ rc = RTLockValidatorRecSharedCheckAndRelease(&pThis->ValidatorRead, NIL_RTTHREAD);
+ if (RT_SUCCESS(rc))
+#endif
+ {
+ if (RT_LIKELY(pThis->cReads > 0))
+ {
+ pThis->cReads--;
+
+ /* Kick off a writer if appropriate. */
+ if ( pThis->cWritesWaiting > 0
+ && !pThis->cReads)
+ {
+ rc = RTSemEventSignal(pThis->WriteEvent);
+ AssertMsgRC(rc, ("Failed to signal writers on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ }
+ }
+ else
+ {
+ AssertFailed();
+ rc = VERR_NOT_OWNER;
+ }
+ }
+ }
+ else
+ {
+ RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
+ if (pThis->hWriter == hNativeSelf)
+ {
+ if (pThis->cWriterReads > 0)
+ {
+#ifdef RTSEMRW_STRICT
+ rc = RTLockValidatorRecExclUnwindMixed(&pThis->ValidatorWrite, &pThis->ValidatorRead.Core);
+ if (RT_SUCCESS(rc))
+#endif
+ {
+ pThis->cWriterReads--;
+ }
+ }
+ else
+ {
+ AssertFailed();
+ rc = VERR_NOT_OWNER;
+ }
+ }
+ else
+ {
+ AssertFailed();
+ rc = VERR_NOT_OWNER;
+ }
+ }
+
+ RTCritSectLeave(&pThis->CritSect);
+ }
+ else
+ AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+
+ return rc;
+}
+RT_EXPORT_SYMBOL(RTSemRWReleaseRead);
+
+
+DECL_FORCE_INLINE(int) rtSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies, bool fInterruptible, PCRTLOCKVALSRCPOS pSrcPos)
+{
+ /*
+ * Validate handle.
+ */
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
+
+ RTMSINTERVAL cMilliesInitial = cMillies;
+ uint64_t tsStart = 0;
+ if (cMillies != RT_INDEFINITE_WAIT && cMillies != 0)
+ tsStart = RTTimeNanoTS();
+
+#ifdef RTSEMRW_STRICT
+ RTTHREAD hThreadSelf = NIL_RTTHREAD;
+ if (cMillies)
+ {
+ hThreadSelf = RTThreadSelfAutoAdopt();
+ int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, cMillies);
+ if (RT_FAILURE(rc9))
+ return rc9;
+ }
+#endif
+
+ /*
+ * Take critsect.
+ */
+ int rc = RTCritSectEnter(&pThis->CritSect);
+ if (RT_FAILURE(rc))
+ {
+ AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ return rc;
+ }
+
+ /*
+ * Check if the state of affairs allows write access.
+ */
+ RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
+ if ( !pThis->cReads
+ && ( ( !pThis->cWrites
+ && ( !pThis->cWritesWaiting /* play fair if we can wait */
+ || !cMillies)
+ )
+ || pThis->hWriter == hNativeSelf
+ )
+ )
+ {
+ /*
+ * Reset the reader event semaphore if necessary.
+ */
+ if (pThis->fNeedResetReadEvent)
+ {
+ pThis->fNeedResetReadEvent = false;
+ rc = RTSemEventMultiReset(pThis->ReadEvent);
+ AssertMsgRC(rc, ("Failed to reset readers, rwsem %p, rc=%Rrc.\n", hRWSem, rc));
+ }
+
+ pThis->cWrites++;
+ pThis->hWriter = hNativeSelf;
+#ifdef RTSEMRW_STRICT
+ RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, pThis->cWrites == 1);
+#endif
+ RTCritSectLeave(&pThis->CritSect);
+ return VINF_SUCCESS;
+ }
+
+ /*
+ * Signal writer presence.
+ */
+ if (cMillies != 0)
+ pThis->cWritesWaiting++;
+
+ RTCritSectLeave(&pThis->CritSect);
+
+ /*
+ * Wait till it's ready for writing.
+ */
+ if (cMillies == 0)
+ return VERR_TIMEOUT;
+
+#ifndef RTSEMRW_STRICT
+ RTTHREAD hThreadSelf = RTThreadSelf();
+#endif
+ for (;;)
+ {
+ if (cMillies != RT_INDEFINITE_WAIT)
+ {
+ int64_t tsDelta = RTTimeNanoTS() - tsStart;
+ if (tsDelta >= 1000000)
+ {
+ tsDelta /= 1000000;
+ if ((uint64_t)tsDelta < cMilliesInitial)
+ cMilliesInitial = (RTMSINTERVAL)tsDelta;
+ else
+ cMilliesInitial = 1;
+ }
+ }
+
+#ifdef RTSEMRW_STRICT
+ rc = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true,
+ cMillies, RTTHREADSTATE_RW_WRITE, false);
+ if (RT_FAILURE(rc))
+ break;
+#else
+ RTThreadBlocking(hThreadSelf, RTTHREADSTATE_RW_WRITE, false);
+ RT_NOREF_PV(pSrcPos);
+#endif
+ int rcWait;
+ if (fInterruptible)
+ rcWait = rc = RTSemEventWaitNoResume(pThis->WriteEvent, cMillies);
+ else
+ rcWait = rc = RTSemEventWait(pThis->WriteEvent, cMillies);
+ RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_RW_WRITE);
+ if (RT_UNLIKELY(RT_FAILURE_NP(rc) && rc != VERR_TIMEOUT)) /* timeouts are handled below */
+ {
+ AssertMsgRC(rc, ("RTSemEventWait failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ break;
+ }
+
+ if (RT_UNLIKELY(pThis->u32Magic != RTSEMRW_MAGIC))
+ {
+ rc = VERR_SEM_DESTROYED;
+ break;
+ }
+
+ /*
+ * Re-take critsect and repeat the check we did prior to this loop.
+ */
+ rc = RTCritSectEnter(&pThis->CritSect);
+ if (RT_FAILURE(rc))
+ {
+ AssertMsgFailed(("RTCritSectEnter failed on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ break;
+ }
+
+ if (!pThis->cReads && (!pThis->cWrites || pThis->hWriter == hNativeSelf))
+ {
+ /*
+ * Reset the reader event semaphore if necessary.
+ */
+ if (pThis->fNeedResetReadEvent)
+ {
+ pThis->fNeedResetReadEvent = false;
+ rc = RTSemEventMultiReset(pThis->ReadEvent);
+ AssertMsgRC(rc, ("Failed to reset readers, rwsem %p, rc=%Rrc.\n", hRWSem, rc));
+ }
+
+ pThis->cWrites++;
+ pThis->hWriter = hNativeSelf;
+ pThis->cWritesWaiting--;
+#ifdef RTSEMRW_STRICT
+ RTLockValidatorRecExclSetOwner(&pThis->ValidatorWrite, hThreadSelf, pSrcPos, true);
+#endif
+
+ RTCritSectLeave(&pThis->CritSect);
+ return VINF_SUCCESS;
+ }
+
+ RTCritSectLeave(&pThis->CritSect);
+
+ /*
+ * Quit if the wait already timed out.
+ */
+ if (rcWait == VERR_TIMEOUT)
+ {
+ rc = VERR_TIMEOUT;
+ break;
+ }
+ }
+
+ /*
+ * Timeout/error case, clean up.
+ */
+ if (pThis->u32Magic == RTSEMRW_MAGIC)
+ {
+ RTCritSectEnter(&pThis->CritSect);
+ /* Adjust this counter, whether we got the critsect or not. */
+ pThis->cWritesWaiting--;
+ RTCritSectLeave(&pThis->CritSect);
+ }
+ return rc;
+}
+
+
+RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+ return rtSemRWRequestWrite(hRWSem, cMillies, false, NULL);
+#else
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+ return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestWrite);
+
+
+RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+ return rtSemRWRequestWrite(hRWSem, cMillies, false, &SrcPos);
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestWriteDebug);
+
+
+RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies)
+{
+#ifndef RTSEMRW_STRICT
+ return rtSemRWRequestWrite(hRWSem, cMillies, true, NULL);
+#else
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
+ return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResume);
+
+
+RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL)
+{
+ RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
+ return rtSemRWRequestWrite(hRWSem, cMillies, true, &SrcPos);
+}
+RT_EXPORT_SYMBOL(RTSemRWRequestWriteNoResumeDebug);
+
+
+RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem)
+{
+
+ /*
+ * Validate handle.
+ */
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+ AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, VERR_INVALID_HANDLE);
+
+ /*
+ * Take critsect.
+ */
+ int rc = RTCritSectEnter(&pThis->CritSect);
+ AssertRCReturn(rc, rc);
+
+ /*
+ * Check if owner.
+ */
+ RTNATIVETHREAD hNativeSelf = pThis->CritSect.NativeThreadOwner;
+ if (pThis->hWriter != hNativeSelf)
+ {
+ RTCritSectLeave(&pThis->CritSect);
+ AssertMsgFailed(("Not read-write owner of rwsem %p.\n", hRWSem));
+ return VERR_NOT_OWNER;
+ }
+
+#ifdef RTSEMRW_STRICT
+ if (pThis->cWrites > 1 || !pThis->cWriterReads) /* don't check+release if VERR_WRONG_ORDER */
+ {
+ int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorWrite, pThis->cWrites == 1);
+ if (RT_FAILURE(rc9))
+ {
+ RTCritSectLeave(&pThis->CritSect);
+ return rc9;
+ }
+ }
+#endif
+
+ /*
+ * Release ownership and remove ourselves from the writers count.
+ */
+ Assert(pThis->cWrites > 0);
+ pThis->cWrites--;
+ if (!pThis->cWrites)
+ {
+ if (RT_UNLIKELY(pThis->cWriterReads > 0))
+ {
+ pThis->cWrites++;
+ RTCritSectLeave(&pThis->CritSect);
+ AssertMsgFailed(("All recursive read locks need to be released prior to the final write lock! (%p)n\n", pThis));
+ return VERR_WRONG_ORDER;
+ }
+
+ pThis->hWriter = NIL_RTNATIVETHREAD;
+ }
+
+ /*
+ * Release the readers if no more writers waiting, otherwise the writers.
+ */
+ if (!pThis->cWritesWaiting)
+ {
+ rc = RTSemEventMultiSignal(pThis->ReadEvent);
+ AssertMsgRC(rc, ("RTSemEventMultiSignal failed for rwsem %p, rc=%Rrc.\n", hRWSem, rc));
+ pThis->fNeedResetReadEvent = true;
+ }
+ else
+ {
+ rc = RTSemEventSignal(pThis->WriteEvent);
+ AssertMsgRC(rc, ("Failed to signal writers on rwsem %p, rc=%Rrc\n", hRWSem, rc));
+ }
+ RTCritSectLeave(&pThis->CritSect);
+
+ return rc;
+}
+RT_EXPORT_SYMBOL(RTSemRWReleaseWrite);
+
+
+RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem)
+{
+ /*
+ * Validate handle.
+ */
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+ AssertPtrReturn(pThis, false);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, false);
+
+ /*
+ * Check ownership.
+ */
+ RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
+ RTNATIVETHREAD hWriter;
+ ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
+ return hWriter == hNativeSelf;
+}
+RT_EXPORT_SYMBOL(RTSemRWIsWriteOwner);
+
+
+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.
+ */
+ RTNATIVETHREAD hNativeSelf = RTThreadNativeSelf();
+ RTNATIVETHREAD hWriter;
+ ASMAtomicUoReadHandle(&pThis->hWriter, &hWriter);
+ if (hWriter == hNativeSelf)
+ return true;
+ if (hWriter != NIL_RTNATIVETHREAD)
+ return false;
+
+#ifdef RTSEMRW_STRICT
+ /*
+ * Ask the lock validator.
+ */
+ NOREF(fWannaHear);
+ return RTLockValidatorRecSharedIsOwner(&pThis->ValidatorRead, NIL_RTTHREAD);
+#else
+ /*
+ * If there are no reads we cannot be one of them... But if there are we
+ * cannot know and can only return what the caller want to hear.
+ */
+ if (pThis->cReads == 0)
+ return false;
+ return fWannaHear;
+#endif
+}
+RT_EXPORT_SYMBOL(RTSemRWIsReadOwner);
+
+
+RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem)
+{
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+
+ /*
+ * Validate handle.
+ */
+ AssertPtrReturn(pThis, 0);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
+
+ /*
+ * Return the requested data.
+ */
+ return pThis->cWrites;
+}
+RT_EXPORT_SYMBOL(RTSemRWGetWriteRecursion);
+
+
+RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem)
+{
+ struct RTSEMRWINTERNAL *pThis = hRWSem;
+
+ /*
+ * Validate handle.
+ */
+ AssertPtrReturn(pThis, 0);
+ AssertReturn(pThis->u32Magic == RTSEMRW_MAGIC, 0);
+
+ /*
+ * Return the requested data.
+ */
+ return pThis->cWriterReads;
+}
+RT_EXPORT_SYMBOL(RTSemRWGetWriterReadRecursion);
+
+
+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->cReads;
+}
+RT_EXPORT_SYMBOL(RTSemRWGetReadCount);
+