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Diffstat (limited to '')
| -rw-r--r-- | src/VBox/Runtime/generic/semrw-generic.cpp | 978 |
1 files changed, 978 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..a8062673 --- /dev/null +++ b/src/VBox/Runtime/generic/semrw-generic.cpp @@ -0,0 +1,978 @@ +/* $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) 2006-2019 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 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); + |