/* $Id$ */
/** @file
* IPRT - Multiple Release Event Semaphore, Linux (2.6.x+).
*/
/*
* Copyright (C) 2006-2012 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.
*/
#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 volatile (".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>
#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 multiple wakup event semaphore.
*/
struct RTSEMEVENTMULTIINTERNAL
{
/** Magic value. */
uint32_t volatile u32Magic;
/** The futex state variable.
* -1 means signaled.
* 0 means not signaled, no waiters.
* 1 means not signaled and that someone is waiting.
*/
int32_t volatile iState;
#ifdef RTSEMEVENTMULTI_STRICT
/** Signallers. */
RTLOCKVALRECSHRD Signallers;
/** Indicates that lock validation should be performed. */
bool volatile fEverHadSignallers;
#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;
}
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);
/*
* Allocate semaphore handle.
*/
struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL));
if (pThis)
{
pThis->u32Magic = RTSEMEVENTMULTI_MAGIC;
pThis->iState = 0;
#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;
#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 (ASMAtomicXchgS32(&pThis->iState, -1) == 1)
{
sys_futex(&pThis->iState, 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;
AssertReturn(VALID_PTR(pThis) && 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.
*/
int32_t iOld = ASMAtomicXchgS32(&pThis->iState, -1);
if (iOld > 0)
{
/* wake up sleeping threads. */
long cWoken = sys_futex(&pThis->iState, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
AssertMsg(cWoken >= 0, ("%ld\n", cWoken)); NOREF(cWoken);
}
Assert(iOld == 0 || iOld == -1 || iOld == 1);
return VINF_SUCCESS;
}
RTDECL(int) RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
{
/*
* Validate input.
*/
struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
AssertReturn(VALID_PTR(pThis) && pThis->u32Magic == RTSEMEVENTMULTI_MAGIC,
VERR_INVALID_HANDLE);
#ifdef RT_STRICT
int32_t i = pThis->iState;
Assert(i == 0 || i == -1 || i == 1);
#endif
/*
* Reset it.
*/
ASMAtomicCmpXchgS32(&pThis->iState, 0, -1);
return VINF_SUCCESS;
}
DECLINLINE(int) rtSemEventLnxMultiWait(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout,
PCRTLOCKVALSRCPOS pSrcPos)
{
/*
* Validate input.
*/
AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
AssertReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, VERR_INVALID_HANDLE);
AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
/*
* Quickly check whether it's signaled.
*/
int32_t iCur = ASMAtomicUoReadS32(&pThis->iState);
Assert(iCur == 0 || iCur == -1 || iCur == 1);
if (iCur == -1)
return VINF_SUCCESS;
/*
* Check and convert the timeout value.
*/
struct timespec ts;
struct timespec *pTimeout = NULL;
uint64_t u64Deadline = 0; /* shut up gcc */
if (!(fFlags & RTSEMWAIT_FLAGS_INDEFINITE))
{
/* If the timeout is zero, then we're done. */
if (!uTimeout)
return VERR_TIMEOUT;
/* Convert it to a deadline + interval timespec. */
if (fFlags & RTSEMWAIT_FLAGS_MILLISECS)
uTimeout = uTimeout < UINT64_MAX / UINT32_C(1000000) * UINT32_C(1000000)
? uTimeout * UINT32_C(1000000)
: UINT64_MAX;
if (uTimeout != UINT64_MAX) /* unofficial way of indicating an indefinite wait */
{
if (fFlags & RTSEMWAIT_FLAGS_RELATIVE)
u64Deadline = RTTimeSystemNanoTS() + uTimeout;
else
{
uint64_t u64Now = RTTimeSystemNanoTS();
if (uTimeout <= u64Now)
return VERR_TIMEOUT;
u64Deadline = uTimeout;
uTimeout -= u64Now;
}
if ( sizeof(ts.tv_sec) >= sizeof(uint64_t)
|| uTimeout <= UINT64_C(1000000000) * UINT32_MAX)
{
ts.tv_nsec = uTimeout % UINT32_C(1000000000);
ts.tv_sec = uTimeout / UINT32_C(1000000000);
pTimeout = &ts;
}
}
}
/*
* 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.
*/
iCur = ASMAtomicUoReadS32(&pThis->iState);
Assert(iCur == 0 || iCur == -1 || iCur == 1);
if ( iCur == 1
|| ASMAtomicCmpXchgS32(&pThis->iState, 1, 0))
{
/* adjust the relative timeout */
if (pTimeout)
{
int64_t i64Diff = u64Deadline - RTTimeSystemNanoTS();
if (i64Diff < 1000)
return VERR_TIMEOUT;
ts.tv_sec = (uint64_t)i64Diff / UINT32_C(1000000000);
ts.tv_nsec = (uint64_t)i64Diff % UINT32_C(1000000000);
}
#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
RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
long rc = sys_futex(&pThis->iState, FUTEX_WAIT, 1, pTimeout, NULL, 0);
RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENTMULTI_MAGIC))
return VERR_SEM_DESTROYED;
if (rc == 0)
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... */
Assert(pTimeout);
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 (iCur == -1)
return VINF_SUCCESS;
}
}
#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);
#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);
#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);
#endif
}
#endif /* glibc < 2.6 || IPRT_WITH_FUTEX_BASED_SEMS */