diff options
Diffstat (limited to 'src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp')
| -rw-r--r-- | src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp | 600 |
1 files changed, 600 insertions, 0 deletions
diff --git a/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp b/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp new file mode 100644 index 00000000..87554838 --- /dev/null +++ b/src/VBox/Runtime/r3/linux/semeventmulti-linux.cpp @@ -0,0 +1,600 @@ +/* $Id: semeventmulti-linux.cpp $ */ +/** @file + * IPRT - Multiple Release Event Semaphore, Linux (2.6.x+). + */ + +/* + * Copyright (C) 2006-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + + +#include <features.h> +#if __GLIBC_PREREQ(2,6) && !defined(IPRT_WITH_FUTEX_BASED_SEMS) + +/* + * glibc 2.6 fixed a serious bug in the mutex implementation. We wrote this + * linux specific event semaphores code in order to work around the bug. As it + * turns out, this code seems to have an unresolved issue (@bugref{2599}), so we'll + * fall back on the pthread based implementation if glibc is known to contain + * the bug fix. + * + * The external reference to epoll_pwait is a hack which prevents that we link + * against glibc < 2.6. + */ +#include "../posix/semeventmulti-posix.cpp" +__asm__ (".global epoll_pwait"); + +#else /* glibc < 2.6 */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include <iprt/semaphore.h> +#include "internal/iprt.h" + +#include <iprt/assert.h> +#include <iprt/asm.h> +#include <iprt/err.h> +#include <iprt/lockvalidator.h> +#include <iprt/mem.h> +#include <iprt/time.h> +#include "internal/magics.h" +#include "internal/strict.h" + + +#include <errno.h> +#include <limits.h> +#include <pthread.h> +#include <unistd.h> +#include <sys/time.h> +#include <sys/syscall.h> + +#include "semwait-linux.h" + + +/********************************************************************************************************************************* +* Structures and Typedefs * +*********************************************************************************************************************************/ +/** + * Linux multiple wakup event semaphore. + */ +struct RTSEMEVENTMULTIINTERNAL +{ + /** Magic value. */ + uint32_t volatile u32Magic; + /** The futex state variable, see RTSEMEVENTMULTI_LNX_XXX. */ + uint32_t volatile uState; +#ifdef RT_STRICT + /** Increased on every signalling call. */ + uint32_t volatile uSignalSerialNo; +#endif +#ifdef RTSEMEVENTMULTI_STRICT + /** Signallers. */ + RTLOCKVALRECSHRD Signallers; + /** Indicates that lock validation should be performed. */ + bool volatile fEverHadSignallers; +#endif +}; + + +/********************************************************************************************************************************* +* Defined Constants And Macros * +*********************************************************************************************************************************/ +/** @name RTSEMEVENTMULTI_LNX_XXX - state + * @{ */ +#define RTSEMEVENTMULTI_LNX_NOT_SIGNALED UINT32_C(0x00000000) +#define RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS UINT32_C(0x00000001) +#define RTSEMEVENTMULTI_LNX_SIGNALED UINT32_C(0x00000003) +/** @} */ + +#define ASSERT_VALID_STATE(a_uState) \ + AssertMsg( (a_uState) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED \ + || (a_uState) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS \ + || (a_uState) == RTSEMEVENTMULTI_LNX_SIGNALED, \ + (#a_uState "=%s\n", a_uState)) + + +/********************************************************************************************************************************* +* Global Variables * +*********************************************************************************************************************************/ +/** Whether we can use FUTEX_WAIT_BITSET. */ +static int volatile g_fCanUseWaitBitSet = -1; + + +RTDECL(int) RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem) +{ + return RTSemEventMultiCreateEx(phEventMultiSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL); +} + + +RTDECL(int) RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass, + const char *pszNameFmt, ...) +{ + AssertReturn(!(fFlags & ~RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER); + + /* + * Make sure we know whether FUTEX_WAIT_BITSET works. + */ + rtSemLinuxCheckForFutexWaitBitSet(&g_fCanUseWaitBitSet); +#if defined(DEBUG_bird) && !defined(IN_GUEST) + Assert(g_fCanUseWaitBitSet == true); +#endif + + /* + * Allocate semaphore handle. + */ + struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL)); + if (pThis) + { + pThis->u32Magic = RTSEMEVENTMULTI_MAGIC; + pThis->uState = RTSEMEVENTMULTI_LNX_NOT_SIGNALED; +#ifdef RT_STRICT + pThis->uSignalSerialNo = 0; +#endif +#ifdef RTSEMEVENTMULTI_STRICT + if (!pszNameFmt) + { + static uint32_t volatile s_iSemEventMultiAnon = 0; + RTLockValidatorRecSharedInit(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis, + true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), + "RTSemEventMulti-%u", ASMAtomicIncU32(&s_iSemEventMultiAnon) - 1); + } + else + { + va_list va; + va_start(va, pszNameFmt); + RTLockValidatorRecSharedInitV(&pThis->Signallers, hClass, RTLOCKVAL_SUB_CLASS_ANY, pThis, + true /*fSignaller*/, !(fFlags & RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL), + pszNameFmt, va); + va_end(va); + } + pThis->fEverHadSignallers = false; +#else + RT_NOREF(hClass, pszNameFmt); +#endif + + *phEventMultiSem = pThis; + return VINF_SUCCESS; + } + return VERR_NO_MEMORY; +} + + +RTDECL(int) RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem) +{ + /* + * Validate input. + */ + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + if (pThis == NIL_RTSEMEVENTMULTI) + return VINF_SUCCESS; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE); + + /* + * Invalidate the semaphore and wake up anyone waiting on it. + */ + ASMAtomicWriteU32(&pThis->u32Magic, RTSEMEVENTMULTI_MAGIC + 1); + if (ASMAtomicXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_SIGNALED) == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS) + { + sys_futex(&pThis->uState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0); + usleep(1000); + } + + /* + * Free the semaphore memory and be gone. + */ +#ifdef RTSEMEVENTMULTI_STRICT + RTLockValidatorRecSharedDelete(&pThis->Signallers); +#endif + RTMemFree(pThis); + return VINF_SUCCESS; +} + + +RTDECL(int) RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem) +{ + /* + * Validate input. + */ + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE); + +#ifdef RTSEMEVENTMULTI_STRICT + if (pThis->fEverHadSignallers) + { + int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD); + if (RT_FAILURE(rc9)) + return rc9; + } +#endif + + /* + * Signal it. + */ +#ifdef RT_STRICT + ASMAtomicIncU32(&pThis->uSignalSerialNo); +#endif + uint32_t uOld = ASMAtomicXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_SIGNALED); + if (uOld == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS) + { + /* wake up sleeping threads. */ + long cWoken = sys_futex(&pThis->uState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0); + AssertMsg(cWoken >= 0, ("%ld\n", cWoken)); NOREF(cWoken); + } + ASSERT_VALID_STATE(uOld); + return VINF_SUCCESS; +} + + +RTDECL(int) RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem) +{ + /* + * Validate input. + */ + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE); +#ifdef RT_STRICT + uint32_t const uState = pThis->uState; + ASSERT_VALID_STATE(uState); +#endif + + /* + * Reset it. + */ + ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED, RTSEMEVENTMULTI_LNX_SIGNALED); + return VINF_SUCCESS; +} + + +/** + * Performs an indefinite wait on the event. + */ +static int rtSemEventMultiLinuxWaitIndefinite(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos) +{ + RT_NOREF(pSrcPos); + + /* + * Quickly check whether it's signaled. + */ + uint32_t uState = ASMAtomicUoReadU32(&pThis->uState); + if (uState == RTSEMEVENTMULTI_LNX_SIGNALED) + return VINF_SUCCESS; + ASSERT_VALID_STATE(uState); + + /* + * The wait loop. + */ +#ifdef RTSEMEVENTMULTI_STRICT + RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt(); +#else + RTTHREAD hThreadSelf = RTThreadSelf(); +#endif + for (unsigned i = 0;; i++) + { + /* + * Start waiting. We only account for there being or having been + * threads waiting on the semaphore to keep things simple. + */ + uState = ASMAtomicUoReadU32(&pThis->uState); + if ( uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS + || ( uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED + && ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS, + RTSEMEVENTMULTI_LNX_NOT_SIGNALED))) + { +#ifdef RTSEMEVENTMULTI_STRICT + if (pThis->fEverHadSignallers) + { + int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false, + RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT_MULTI, true); + if (RT_FAILURE(rc9)) + return rc9; + } +#endif +#ifdef RT_STRICT + uint32_t const uPrevSignalSerialNo = ASMAtomicReadU32(&pThis->uSignalSerialNo); +#endif + RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true); + long rc = sys_futex(&pThis->uState, FUTEX_WAIT, 1, NULL /*pTimeout*/, NULL, 0); + RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI); + + /* Check that the structure is still alive before continuing. */ + if (RT_LIKELY(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC)) + { /*likely*/ } + else + return VERR_SEM_DESTROYED; + + /* + * Return if success. + */ + if (rc == 0) + { + Assert(uPrevSignalSerialNo != ASMAtomicReadU32(&pThis->uSignalSerialNo)); + return VINF_SUCCESS; + } + + /* + * Act on the wakup code. + */ + if (rc == -EWOULDBLOCK) + /* retry, the value changed. */; + else if (rc == -EINTR) + { + if (fFlags & RTSEMWAIT_FLAGS_NORESUME) + return VERR_INTERRUPTED; + } + else + { + /* this shouldn't happen! */ + AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno)); + return RTErrConvertFromErrno(rc); + } + } + else if (uState == RTSEMEVENTMULTI_LNX_SIGNALED) + return VINF_SUCCESS; + else + ASSERT_VALID_STATE(uState); + } +} + + +/** + * Handle polling (timeout already expired at the time of the call). + * + * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED. + * @param pThis The semaphore. + */ +static int rtSemEventMultiLinuxWaitPoll(struct RTSEMEVENTMULTIINTERNAL *pThis) +{ + uint32_t uState = ASMAtomicUoReadU32(&pThis->uState); + if (uState == RTSEMEVENTMULTI_LNX_SIGNALED) + return VINF_SUCCESS; + return VERR_TIMEOUT; +} + + +/** + * Performs an indefinite wait on the event. + */ +static int rtSemEventMultiLinuxWaitTimed(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout, + PCRTLOCKVALSRCPOS pSrcPos) +{ + RT_NOREF(pSrcPos); + + /* + * Quickly check whether it's signaled. + */ + uint32_t uState = ASMAtomicUoReadU32(&pThis->uState); + if (uState == RTSEMEVENTMULTI_LNX_SIGNALED) + return VINF_SUCCESS; + ASSERT_VALID_STATE(uState); + + /* + * Convert the timeout value. + */ + struct timespec TsTimeout; + int iWaitOp; + uint32_t uWaitVal3; + uint64_t nsAbsTimeout = uTimeout; /* (older gcc maybe used uninitialized) */ + uTimeout = rtSemLinuxCalcDeadline(fFlags, uTimeout, g_fCanUseWaitBitSet, &TsTimeout, &iWaitOp, &uWaitVal3, &nsAbsTimeout); + if (uTimeout == 0) + return rtSemEventMultiLinuxWaitPoll(pThis); + if (uTimeout == UINT64_MAX) + return rtSemEventMultiLinuxWaitIndefinite(pThis, fFlags, pSrcPos); + + /* + * The wait loop. + */ +#ifdef RTSEMEVENTMULTI_STRICT + RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt(); +#else + RTTHREAD hThreadSelf = RTThreadSelf(); +#endif + for (unsigned i = 0;; i++) + { + /* + * Start waiting. We only account for there being or having been + * threads waiting on the semaphore to keep things simple. + */ + uState = ASMAtomicUoReadU32(&pThis->uState); + if ( uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS + || ( uState == RTSEMEVENTMULTI_LNX_NOT_SIGNALED + && ASMAtomicCmpXchgU32(&pThis->uState, RTSEMEVENTMULTI_LNX_NOT_SIGNALED_WAITERS, + RTSEMEVENTMULTI_LNX_NOT_SIGNALED))) + { +#ifdef RTSEMEVENTMULTI_STRICT + if (pThis->fEverHadSignallers) + { + int rc9 = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false, + uTimeout / UINT32_C(1000000), RTTHREADSTATE_EVENT_MULTI, true); + if (RT_FAILURE(rc9)) + return rc9; + } +#endif +#ifdef RT_STRICT + uint32_t const uPrevSignalSerialNo = ASMAtomicReadU32(&pThis->uSignalSerialNo); +#endif + RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true); + long rc = sys_futex(&pThis->uState, iWaitOp, 1, &TsTimeout, NULL, uWaitVal3); + RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI); + + /* Check that the structure is still alive before continuing. */ + if (RT_LIKELY(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC)) + { /*likely*/ } + else + return VERR_SEM_DESTROYED; + + /* + * Return if success. + */ + if (rc == 0) + { + Assert(uPrevSignalSerialNo != ASMAtomicReadU32(&pThis->uSignalSerialNo)); + return VINF_SUCCESS; + } + + /* + * Act on the wakup code. + */ + if (rc == -ETIMEDOUT) + { + /** @todo something is broken here. shows up every now and again in the ata + * code. Should try to run the timeout against RTTimeMilliTS to + * check that it's doing the right thing... */ +#ifdef RT_STRICT + uint64_t const uNow = RTTimeNanoTS(); + AssertMsg(uNow >= nsAbsTimeout || nsAbsTimeout - uNow < RT_NS_1MS, + ("%#RX64 - %#RX64 => %#RX64 (%RI64)\n", nsAbsTimeout, uNow, nsAbsTimeout - uNow, nsAbsTimeout - uNow)); +#endif + return VERR_TIMEOUT; + } + if (rc == -EWOULDBLOCK) + { + /* retry, the value changed. */; + } + else if (rc == -EINTR) + { + if (fFlags & RTSEMWAIT_FLAGS_NORESUME) + return VERR_INTERRUPTED; + } + else + { + /* this shouldn't happen! */ + AssertMsgFailed(("rc=%ld errno=%d\n", rc, errno)); + return RTErrConvertFromErrno(rc); + } + } + else if (uState == RTSEMEVENTMULTI_LNX_SIGNALED) + return VINF_SUCCESS; + else + ASSERT_VALID_STATE(uState); + + /* adjust the relative timeout if relative */ + if (iWaitOp == FUTEX_WAIT) + { + int64_t i64Diff = nsAbsTimeout - RTTimeSystemNanoTS(); + if (i64Diff < 1000) + return VERR_TIMEOUT; + TsTimeout.tv_sec = (uint64_t)i64Diff / RT_NS_1SEC; + TsTimeout.tv_nsec = (uint64_t)i64Diff % RT_NS_1SEC; + } + } +} + +/** + * Internal wait worker function. + */ +DECLINLINE(int) rtSemEventLnxMultiWait(RTSEMEVENTMULTI hEventSem, uint32_t fFlags, uint64_t uTimeout, PCRTLOCKVALSRCPOS pSrcPos) +{ + /* + * Validate input. + */ + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventSem; + AssertPtrReturn(pThis, VERR_INVALID_HANDLE); + AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE); + AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER); + + /* + * Timed or indefinite wait? + */ + if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE) + return rtSemEventMultiLinuxWaitIndefinite(pThis, fFlags, pSrcPos); + return rtSemEventMultiLinuxWaitTimed(hEventSem, fFlags, uTimeout, pSrcPos); +} + + +#undef RTSemEventMultiWaitEx +RTDECL(int) RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout) +{ +#ifndef RTSEMEVENT_STRICT + return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, NULL); +#else + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API(); + return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, &SrcPos); +#endif +} + + +RTDECL(int) RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout, + RTHCUINTPTR uId, RT_SRC_POS_DECL) +{ + RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API(); + return rtSemEventLnxMultiWait(hEventMultiSem, fFlags, uTimeout, &SrcPos); +} + + +RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread) +{ +#ifdef RTSEMEVENTMULTI_STRICT + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + AssertPtrReturnVoid(pThis); + AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC); + + ASMAtomicWriteBool(&pThis->fEverHadSignallers, true); + RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL); +#else + RT_NOREF(hEventMultiSem, hThread); +#endif +} + + +RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread) +{ +#ifdef RTSEMEVENTMULTI_STRICT + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + AssertPtrReturnVoid(pThis); + AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC); + + ASMAtomicWriteBool(&pThis->fEverHadSignallers, true); + RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL); +#else + RT_NOREF(hEventMultiSem, hThread); +#endif +} + + +RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread) +{ +#ifdef RTSEMEVENTMULTI_STRICT + struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem; + AssertPtrReturnVoid(pThis); + AssertReturnVoid(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC); + + RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread); +#else + RT_NOREF(hEventMultiSem, hThread); +#endif +} + +#endif /* glibc < 2.6 || IPRT_WITH_FUTEX_BASED_SEMS */ + |