diff options
Diffstat (limited to 'src/VBox/Runtime/r3/linux/semmutex-linux.cpp')
| -rw-r--r-- | src/VBox/Runtime/r3/linux/semmutex-linux.cpp | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r3/linux/semmutex-linux.cpp b/src/VBox/Runtime/r3/linux/semmutex-linux.cpp new file mode 100644 index 00000000..69254b94 --- /dev/null +++ b/src/VBox/Runtime/r3/linux/semmutex-linux.cpp @@ -0,0 +1,465 @@ +/* $Id: semmutex-linux.cpp $ */ +/** @file + * IPRT - Mutex Semaphore, Linux (2.6.x+). + */ + +/* + * 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 * +*********************************************************************************************************************************/ +#include <iprt/semaphore.h> +#include "internal/iprt.h" + +#include <iprt/alloc.h> +#include <iprt/asm.h> +#include <iprt/assert.h> +#include <iprt/err.h> +#include <iprt/lockvalidator.h> +#include <iprt/thread.h> +#include <iprt/time.h> +#include "internal/magics.h" +#include "internal/strict.h" + +#include <errno.h> +#include <limits.h> +#include <pthread.h> +#include <unistd.h> +#include <sys/time.h> +#include <sys/syscall.h> +#if 0 /* With 2.6.17 futex.h has become C++ unfriendly. */ +# include <linux/futex.h> +#else +# define FUTEX_WAIT 0 +# define FUTEX_WAKE 1 +#endif + + +/********************************************************************************************************************************* +* Structures and Typedefs * +*********************************************************************************************************************************/ +/** + * Linux internal representation of a Mutex semaphore. + */ +struct RTSEMMUTEXINTERNAL +{ + /** The futex state variable. + * 0 means unlocked. + * 1 means locked, no waiters. + * 2 means locked, one or more waiters. + */ + int32_t volatile iState; + /** Nesting count. */ + uint32_t volatile cNestings; + /** The owner of the mutex. */ + pthread_t volatile Owner; + /** Magic value (RTSEMMUTEX_MAGIC). */ + uint32_t volatile u32Magic; +#ifdef RTSEMMUTEX_STRICT + /** Lock validator record associated with this mutex. */ + RTLOCKVALRECEXCL ValidatorRec; +#endif +}; + + + +/** + * Wrapper for the futex syscall. + */ +static long sys_futex(int32_t volatile *uaddr, int op, int val, struct timespec *utime, int32_t *uaddr2, int val3) +{ + errno = 0; + long rc = syscall(__NR_futex, uaddr, op, val, utime, uaddr2, val3); + if (rc < 0) + { + Assert(rc == -1); + rc = -errno; + } + return rc; +} + + +#undef RTSemMutexCreate +RTDECL(int) RTSemMutexCreate(PRTSEMMUTEX phMutexSem) +{ + return RTSemMutexCreateEx(phMutexSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_NONE, NULL); +} + + +RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags, + RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...) +{ + AssertReturn(!(fFlags & ~RTSEMMUTEX_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER); + + /* + * Allocate semaphore handle. + */ + struct RTSEMMUTEXINTERNAL *pThis = (struct RTSEMMUTEXINTERNAL *)RTMemAlloc(sizeof(struct RTSEMMUTEXINTERNAL)); + if (pThis) + { + pThis->u32Magic = RTSEMMUTEX_MAGIC; + pThis->iState = 0; + pThis->Owner = (pthread_t)~0; + pThis->cNestings = 0; +#ifdef RTSEMMUTEX_STRICT + if (!pszNameFmt) + { + static uint32_t volatile s_iMutexAnon = 0; + RTLockValidatorRecExclInit(&pThis->ValidatorRec, hClass, uSubClass, pThis, + !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), + "RTSemMutex-%u", ASMAtomicIncU32(&s_iMutexAnon) - 1); + } + else + { + va_list va; + va_start(va, pszNameFmt); + RTLockValidatorRecExclInitV(&pThis->ValidatorRec, hClass, uSubClass, pThis, + !(fFlags & RTSEMMUTEX_FLAGS_NO_LOCK_VAL), pszNameFmt, va); + va_end(va); + } +#else + RT_NOREF(hClass, uSubClass, pszNameFmt); +#endif + + *phMutexSem = pThis; + return VINF_SUCCESS; + } + + return VERR_NO_MEMORY; +} + + +RTDECL(int) RTSemMutexDestroy(RTSEMMUTEX hMutexSem) +{ + /* + * Validate input. + */ + if (hMutexSem == NIL_RTSEMMUTEX) + return VINF_SUCCESS; + struct RTSEMMUTEXINTERNAL *pThis = hMutexSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertMsgReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, + ("hMutexSem=%p u32Magic=%#x\n", pThis, pThis->u32Magic), + VERR_INVALID_HANDLE); + + /* + * Invalidate the semaphore and wake up anyone waiting on it. + */ + ASMAtomicWriteU32(&pThis->u32Magic, RTSEMMUTEX_MAGIC_DEAD); + if (ASMAtomicXchgS32(&pThis->iState, 0) > 0) + { + sys_futex(&pThis->iState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0); + usleep(1000); + } + pThis->Owner = (pthread_t)~0; + pThis->cNestings = 0; +#ifdef RTSEMMUTEX_STRICT + RTLockValidatorRecExclDelete(&pThis->ValidatorRec); +#endif + + /* + * Free the semaphore memory and be gone. + */ + RTMemFree(pThis); + return VINF_SUCCESS; +} + + +RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass) +{ +#ifdef RTSEMMUTEX_STRICT + /* + * Validate. + */ + RTSEMMUTEXINTERNAL *pThis = hMutexSem; + AssertPtrReturn(pThis, RTLOCKVAL_SUB_CLASS_INVALID); + AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, RTLOCKVAL_SUB_CLASS_INVALID); + + return RTLockValidatorRecExclSetSubClass(&pThis->ValidatorRec, uSubClass); +#else + RT_NOREF(hMutexSem, uSubClass); + return RTLOCKVAL_SUB_CLASS_INVALID; +#endif +} + + +DECL_FORCE_INLINE(int) rtSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, bool fAutoResume, PCRTLOCKVALSRCPOS pSrcPos) +{ + RT_NOREF(pSrcPos); + + /* + * Validate input. + */ + struct RTSEMMUTEXINTERNAL *pThis = hMutexSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE); + + /* + * Check if nested request. + */ + pthread_t Self = pthread_self(); + if ( pThis->Owner == Self + && pThis->cNestings > 0) + { +#ifdef RTSEMMUTEX_STRICT + int rc9 = RTLockValidatorRecExclRecursion(&pThis->ValidatorRec, pSrcPos); + if (RT_FAILURE(rc9)) + return rc9; +#endif + ASMAtomicIncU32(&pThis->cNestings); + return VINF_SUCCESS; + } + +#ifdef RTSEMMUTEX_STRICT + RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt(); + if (cMillies) + { + int rc9 = RTLockValidatorRecExclCheckOrder(&pThis->ValidatorRec, hThreadSelf, pSrcPos, cMillies); + if (RT_FAILURE(rc9)) + return rc9; + } +#else + RTTHREAD hThreadSelf = RTThreadSelf(); +#endif + + /* + * Convert timeout value. + */ + struct timespec ts; + struct timespec *pTimeout = NULL; + uint64_t u64End = 0; /* shut up gcc */ + if (cMillies != RT_INDEFINITE_WAIT) + { + ts.tv_sec = cMillies / 1000; + ts.tv_nsec = (cMillies % 1000) * UINT32_C(1000000); + u64End = RTTimeSystemNanoTS() + cMillies * UINT64_C(1000000); + pTimeout = &ts; + } + + /* + * Lock the mutex. + * Optimize for the uncontended case (makes 1-2 ns difference). + */ + if (RT_UNLIKELY(!ASMAtomicCmpXchgS32(&pThis->iState, 1, 0))) + { + for (;;) + { + int32_t iOld = ASMAtomicXchgS32(&pThis->iState, 2); + + /* + * Was the lock released in the meantime? This is unlikely (but possible) + */ + if (RT_UNLIKELY(iOld == 0)) + break; + + /* + * Go to sleep. + */ + if (pTimeout && ( pTimeout->tv_sec || pTimeout->tv_nsec )) + { +#ifdef RTSEMMUTEX_STRICT + int rc9 = RTLockValidatorRecExclCheckBlocking(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true, + cMillies, RTTHREADSTATE_MUTEX, true); + if (RT_FAILURE(rc9)) + return rc9; +#else + RTThreadBlocking(hThreadSelf, RTTHREADSTATE_MUTEX, true); +#endif + } + + long rc = sys_futex(&pThis->iState, FUTEX_WAIT, 2, pTimeout, NULL, 0); + + RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_MUTEX); + if (RT_UNLIKELY(pThis->u32Magic != RTSEMMUTEX_MAGIC)) + return VERR_SEM_DESTROYED; + + /* + * Act on the wakup code. + */ + if (rc == -ETIMEDOUT) + { + Assert(pTimeout); + return VERR_TIMEOUT; + } + if (rc == 0) + /* we'll leave the loop now unless another thread is faster */; + else if (rc == -EWOULDBLOCK) + /* retry with new value. */; + else if (rc == -EINTR) + { + if (!fAutoResume) + return VERR_INTERRUPTED; + } + else + { + /* this shouldn't happen! */ + AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno)); + return RTErrConvertFromErrno(rc); + } + + /* adjust the relative timeout */ + if (pTimeout) + { + int64_t i64Diff = u64End - RTTimeSystemNanoTS(); + if (i64Diff < 1000) + { + rc = VERR_TIMEOUT; + break; + } + ts.tv_sec = (uint64_t)i64Diff / UINT32_C(1000000000); + ts.tv_nsec = (uint64_t)i64Diff % UINT32_C(1000000000); + } + } + + /* + * When leaving this loop, iState is set to 2. This means that we gained the + * lock and there are _possibly_ some waiters. We don't know exactly as another + * thread might entered this loop at nearly the same time. Therefore we will + * call futex_wakeup once too often (if _no_ other thread entered this loop). + * The key problem is the simple futex_wait test for x != y (iState != 2) in + * our case). + */ + } + + /* + * Set the owner and nesting. + */ + pThis->Owner = Self; + ASMAtomicWriteU32(&pThis->cNestings, 1); +#ifdef RTSEMMUTEX_STRICT + RTLockValidatorRecExclSetOwner(&pThis->ValidatorRec, hThreadSelf, pSrcPos, true); +#endif + return VINF_SUCCESS; +} + + +#undef RTSemMutexRequest +RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies) +{ +#ifndef RTSEMMUTEX_STRICT + int rc = rtSemMutexRequest(hMutexSem, cMillies, true, NULL); +#else + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API(); + int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos); +#endif + Assert(rc != VERR_INTERRUPTED); + return rc; +} + + +RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL) +{ + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API(); + int rc = rtSemMutexRequest(hMutexSem, cMillies, true, &SrcPos); + Assert(rc != VERR_INTERRUPTED); + return rc; +} + + +#undef RTSemMutexRequestNoResume +RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies) +{ +#ifndef RTSEMMUTEX_STRICT + return rtSemMutexRequest(hMutexSem, cMillies, false, NULL); +#else + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API(); + return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos); +#endif +} + + +RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL) +{ + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API(); + return rtSemMutexRequest(hMutexSem, cMillies, false, &SrcPos); +} + + +RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMutexSem) +{ + /* + * Validate input. + */ + struct RTSEMMUTEXINTERNAL *pThis = hMutexSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, VERR_INVALID_HANDLE); + +#ifdef RTSEMMUTEX_STRICT + int rc9 = RTLockValidatorRecExclReleaseOwner(&pThis->ValidatorRec, pThis->cNestings == 1); + if (RT_FAILURE(rc9)) + return rc9; +#endif + + /* + * Check if nested. + */ + pthread_t Self = pthread_self(); + if (RT_UNLIKELY( pThis->Owner != Self + || pThis->cNestings == 0)) + { + AssertMsgFailed(("Not owner of mutex %p!! Self=%08x Owner=%08x cNestings=%d\n", + pThis, Self, pThis->Owner, pThis->cNestings)); + return VERR_NOT_OWNER; + } + + /* + * If nested we'll just pop a nesting. + */ + if (pThis->cNestings > 1) + { + ASMAtomicDecU32(&pThis->cNestings); + return VINF_SUCCESS; + } + + /* + * Clear the state. (cNestings == 1) + */ + pThis->Owner = (pthread_t)~0; + ASMAtomicWriteU32(&pThis->cNestings, 0); + + /* + * Release the mutex. + */ + int32_t iNew = ASMAtomicDecS32(&pThis->iState); + if (RT_UNLIKELY(iNew != 0)) + { + /* somebody is waiting, try wake up one of them. */ + ASMAtomicXchgS32(&pThis->iState, 0); + (void)sys_futex(&pThis->iState, FUTEX_WAKE, 1, NULL, NULL, 0); + } + return VINF_SUCCESS; +} + + +RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem) +{ + /* + * Validate. + */ + RTSEMMUTEXINTERNAL *pThis = hMutexSem; + AssertPtrReturn(pThis, false); + AssertReturn(pThis->u32Magic == RTSEMMUTEX_MAGIC, false); + + return pThis->Owner != (pthread_t)~0; +} + |