path: root/src/VBox/Runtime/r3/posix/semeventmulti-posix.cpp

/* $Id: semeventmulti-posix.cpp $ */
/** @file
 * IPRT - Multiple Release Event Semaphore, POSIX.
 */

/*
 * 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/asm.h>
#include <iprt/assert.h>
#include <iprt/err.h>
#include <iprt/lockvalidator.h>
#include <iprt/mem.h>
#include <iprt/time.h>

#include "internal/strict.h"

#include <errno.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/time.h>


/*********************************************************************************************************************************
*   Defined Constants And Macros                                                                                                 *
*********************************************************************************************************************************/
/** @def IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
 * Set if the platform implements pthread_condattr_setclock().
 * Enables the use of the monotonic clock for waiting on condition variables. */
#ifndef IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
/* Linux detection */
# if defined(RT_OS_LINUX) && defined(__USE_XOPEN2K)
#  include <features.h>
#  if __GLIBC_PREREQ(2,6) /** @todo figure the exact version where this was added */
#   define IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK
#  endif
# endif
/** @todo check other platforms */
#endif


/*********************************************************************************************************************************
*   Structures and Typedefs                                                                                                      *
*********************************************************************************************************************************/
/** Posix internal representation of a Mutex Multi semaphore.
 * The POSIX implementation uses a mutex and a condition variable to implement
 * the automatic reset event semaphore semantics. */
struct RTSEMEVENTMULTIINTERNAL
{
    /** pthread condition. */
    pthread_cond_t      Cond;
    /** pthread mutex which protects the condition and the event state. */
    pthread_mutex_t     Mutex;
    /** The state of the semaphore.
     * This is operated while owning mutex and using atomic updating. */
    volatile uint32_t   u32State;
    /** Number of waiters. */
    volatile uint32_t   cWaiters;
#ifdef RTSEMEVENTMULTI_STRICT
    /** Signallers. */
    RTLOCKVALRECSHRD    Signallers;
    /** Indicates that lock validation should be performed. */
    bool volatile       fEverHadSignallers;
#endif
    /** Set if we're using the monotonic clock. */
    bool                fMonotonicClock;
};

/** The values of the u32State variable in RTSEMEVENTMULTIINTERNAL.
 * @{ */
/** The object isn't initialized. */
#define EVENTMULTI_STATE_UNINITIALIZED   0
/** The semaphore is signaled. */
#define EVENTMULTI_STATE_SIGNALED        0xff00ff00
/** The semaphore is not signaled. */
#define EVENTMULTI_STATE_NOT_SIGNALED    0x00ff00ff
/** @} */



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.
     */
    int rc;
    struct RTSEMEVENTMULTIINTERNAL *pThis = (struct RTSEMEVENTMULTIINTERNAL *)RTMemAlloc(sizeof(struct RTSEMEVENTMULTIINTERNAL));
    if (pThis)
    {
        /*
         * Create the condition variable.
         */
        pthread_condattr_t CondAttr;
        rc = pthread_condattr_init(&CondAttr);
        if (!rc)
        {
#if defined(CLOCK_MONOTONIC) && defined(IPRT_HAVE_PTHREAD_CONDATTR_SETCLOCK)
            /* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
            rc = pthread_condattr_setclock(&CondAttr, CLOCK_MONOTONIC);
            pThis->fMonotonicClock = rc == 0;
#else
            pThis->fMonotonicClock = false;
#endif
            rc = pthread_cond_init(&pThis->Cond, &CondAttr);
            if (!rc)
            {
                /*
                 * Create the semaphore.
                 */
                rc = pthread_mutex_init(&pThis->Mutex, NULL);
                if (!rc)
                {
                    pthread_condattr_destroy(&CondAttr);

                    ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
                    ASMAtomicXchgU32(&pThis->cWaiters, 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;
#else
                    RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
#endif

                    *phEventMultiSem = pThis;
                    return VINF_SUCCESS;
                }

                pthread_cond_destroy(&pThis->Cond);
            }
            pthread_condattr_destroy(&CondAttr);
        }

        rc = RTErrConvertFromErrno(rc);
        RTMemFree(pThis);
    }
    else
        rc = VERR_NO_MEMORY;

    return rc;

}


RTDECL(int)  RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem)
{
    /*
     * Validate handle.
     */
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    if (pThis == NIL_RTSEMEVENTMULTI)
        return VINF_SUCCESS;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    uint32_t u32 = pThis->u32State;
    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);

    /*
     * Abort all waiters forcing them to return failure.
     */
    int rc;
    for (int i = 30; i > 0; i--)
    {
        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_UNINITIALIZED);
        rc = pthread_cond_destroy(&pThis->Cond);
        if (rc != EBUSY)
            break;
        pthread_cond_broadcast(&pThis->Cond);
        usleep(1000);
    }
    if (rc)
    {
        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d.\n", hEventMultiSem, rc));
        return RTErrConvertFromErrno(rc);
    }

    /*
     * Destroy the semaphore
     * If it's busy we'll wait a bit to give the threads a chance to be scheduled.
     */
    for (int i = 30; i > 0; i--)
    {
        rc = pthread_mutex_destroy(&pThis->Mutex);
        if (rc != EBUSY)
            break;
        usleep(1000);
    }
    if (rc)
    {
        AssertMsgFailed(("Failed to destroy event sem %p, rc=%d. (mutex)\n", hEventMultiSem, rc));
        return RTErrConvertFromErrno(rc);
    }

    /*
     * 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);
    uint32_t u32 = pThis->u32State;
    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);

#ifdef RTSEMEVENTMULTI_STRICT
    if (pThis->fEverHadSignallers)
    {
        int rc9 = RTLockValidatorRecSharedCheckSignaller(&pThis->Signallers, NIL_RTTHREAD);
        if (RT_FAILURE(rc9))
            return rc9;
    }
#endif

    /*
     * Lock the mutex semaphore.
     */
    int rc = pthread_mutex_lock(&pThis->Mutex);
    if (rc)
    {
        AssertMsgFailed(("Failed to lock event sem %p, rc=%d.\n", hEventMultiSem, rc));
        return RTErrConvertFromErrno(rc);
    }

    /*
     * Check the state.
     */
    if (pThis->u32State == EVENTMULTI_STATE_NOT_SIGNALED)
    {
        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_SIGNALED);
        rc = pthread_cond_broadcast(&pThis->Cond);
        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d.\n", hEventMultiSem, rc));
    }
    else if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
    {
        rc = pthread_cond_broadcast(&pThis->Cond); /* give'm another kick... */
        AssertMsg(!rc, ("Failed to signal event sem %p, rc=%d. (2)\n", hEventMultiSem, rc));
    }
    else
        rc = VERR_SEM_DESTROYED;

    /*
     * Release the mutex and return.
     */
    int rc2 = pthread_mutex_unlock(&pThis->Mutex);
    AssertMsg(!rc2, ("Failed to unlock event sem %p, rc=%d.\n", hEventMultiSem, rc));
    if (rc)
        return RTErrConvertFromErrno(rc);
    if (rc2)
        return RTErrConvertFromErrno(rc2);

    return VINF_SUCCESS;
}


RTDECL(int)  RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem)
{
    /*
     * Validate input.
     */
    int rc = VINF_SUCCESS;
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    uint32_t u32 = pThis->u32State;
    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);

    /*
     * Lock the mutex semaphore.
     */
    int rcPosix = pthread_mutex_lock(&pThis->Mutex);
    if (RT_UNLIKELY(rcPosix))
    {
        AssertMsgFailed(("Failed to lock event multi sem %p, rc=%d.\n", hEventMultiSem, rcPosix));
        return RTErrConvertFromErrno(rcPosix);
    }

    /*
     * Check the state.
     */
    if (pThis->u32State == EVENTMULTI_STATE_SIGNALED)
        ASMAtomicXchgU32(&pThis->u32State, EVENTMULTI_STATE_NOT_SIGNALED);
    else if (pThis->u32State != EVENTMULTI_STATE_NOT_SIGNALED)
        rc = VERR_SEM_DESTROYED;

    /*
     * Release the mutex and return.
     */
    rcPosix = pthread_mutex_unlock(&pThis->Mutex);
    if (RT_UNLIKELY(rcPosix))
    {
        AssertMsgFailed(("Failed to unlock event multi sem %p, rc=%d.\n", hEventMultiSem, rcPosix));
        return RTErrConvertFromErrno(rcPosix);
    }

    return rc;
}


/**
 * Handle polling (timeout already expired at the time of the call).
 *
 * @returns VINF_SUCCESS, VERR_TIMEOUT, VERR_SEM_DESTROYED.
 * @param   pThis               The semaphore.
 */
DECLINLINE(int) rtSemEventMultiPosixWaitPoll(struct RTSEMEVENTMULTIINTERNAL *pThis)
{
    int rc = pthread_mutex_lock(&pThis->Mutex);
    AssertMsgReturn(!rc, ("Failed to lock event multi sem %p, rc=%d.\n", pThis, rc), RTErrConvertFromErrno(rc));

    uint32_t const u32State = pThis->u32State;

    rc = pthread_mutex_unlock(&pThis->Mutex);
    AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc)); NOREF(rc);

    return u32State == EVENTMULTI_STATE_SIGNALED
         ? VINF_SUCCESS
         : u32State != EVENTMULTI_STATE_UNINITIALIZED
         ? VERR_TIMEOUT
         : VERR_SEM_DESTROYED;
}



/**
 * Implements the indefinite wait.
 *
 * @returns See RTSemEventMultiWaitEx.
 * @param   pThis               The semaphore.
 * @param   fFlags              See RTSemEventMultiWaitEx.
 * @param   pSrcPos             The source position, can be NULL.
 */
static int rtSemEventMultiPosixWaitIndefinite(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, PCRTLOCKVALSRCPOS pSrcPos)
{
    /* take mutex */
    int rc = pthread_mutex_lock(&pThis->Mutex);
    AssertMsgReturn(!rc, ("Failed to lock event multi sem %p, rc=%d.\n", pThis, rc), RTErrConvertFromErrno(rc));
    ASMAtomicIncU32(&pThis->cWaiters);

    for (;;)
    {
        /* check state. */
        uint32_t const u32State = pThis->u32State;
        if (u32State != EVENTMULTI_STATE_NOT_SIGNALED)
        {
            ASMAtomicDecU32(&pThis->cWaiters);
            rc = pthread_mutex_unlock(&pThis->Mutex);
            AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc));
            return u32State == EVENTMULTI_STATE_SIGNALED
                 ? VINF_SUCCESS
                 : VERR_SEM_DESTROYED;
        }

        /* wait */
#ifdef RTSEMEVENTMULTI_STRICT
        RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
        if (pThis->fEverHadSignallers)
        {
            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
                                                       RT_INDEFINITE_WAIT, RTTHREADSTATE_EVENT_MULTI, true);
            if (RT_FAILURE(rc))
            {
                ASMAtomicDecU32(&pThis->cWaiters);
                pthread_mutex_unlock(&pThis->Mutex);
                return rc;
            }
        }
#else
        RTTHREAD hThreadSelf = RTThreadSelf();
        RT_NOREF_PV(pSrcPos);
#endif
        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
        /** @todo interruptible wait is not implementable... */ NOREF(fFlags);
        rc = pthread_cond_wait(&pThis->Cond, &pThis->Mutex);
        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
        if (RT_UNLIKELY(rc))
        {
            AssertMsgFailed(("Failed to wait on event multi sem %p, rc=%d.\n", pThis, rc));
            ASMAtomicDecU32(&pThis->cWaiters);
            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
            AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc2)); NOREF(rc2);
            return RTErrConvertFromErrno(rc);
        }
    }
}


/**
 * Implements the timed wait.
 *
 * @returns See RTSemEventMultiWaitEx
 * @param   pThis               The semaphore.
 * @param   fFlags              See RTSemEventMultiWaitEx.
 * @param   uTimeout            See RTSemEventMultiWaitEx.
 * @param   pSrcPos             The source position, can be NULL.
 */
static int rtSemEventMultiPosixWaitTimed(struct RTSEMEVENTMULTIINTERNAL *pThis, uint32_t fFlags, uint64_t uTimeout,
                                         PCRTLOCKVALSRCPOS pSrcPos)
{
    /*
     * Convert uTimeout to a relative value in nano seconds.
     */
    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 */
        return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);

    uint64_t uAbsTimeout = uTimeout;
    if (fFlags & RTSEMWAIT_FLAGS_ABSOLUTE)
    {
        uint64_t u64Now = RTTimeSystemNanoTS();
        uTimeout = uTimeout > u64Now ? uTimeout - u64Now : 0;
    }

    if (uTimeout == 0)
        return rtSemEventMultiPosixWaitPoll(pThis);

    /*
     * Get current time and calc end of deadline relative to real time.
     */
    struct timespec     ts = {0,0};
    if (!pThis->fMonotonicClock)
    {
#if defined(RT_OS_DARWIN) || defined(RT_OS_HAIKU)
        struct timeval  tv = {0,0};
        gettimeofday(&tv, NULL);
        ts.tv_sec = tv.tv_sec;
        ts.tv_nsec = tv.tv_usec * 1000;
#else
        clock_gettime(CLOCK_REALTIME, &ts);
#endif
        struct timespec tsAdd;
        tsAdd.tv_nsec = uTimeout % UINT32_C(1000000000);
        tsAdd.tv_sec  = uTimeout / UINT32_C(1000000000);
        if (   sizeof(ts.tv_sec) < sizeof(uint64_t)
            && (   uTimeout > UINT64_C(1000000000) * UINT32_MAX
                || (uint64_t)ts.tv_sec + tsAdd.tv_sec >= UINT32_MAX) )
            return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);

        ts.tv_sec  += tsAdd.tv_sec;
        ts.tv_nsec += tsAdd.tv_nsec;
        if (ts.tv_nsec >= 1000000000)
        {
            ts.tv_nsec -= 1000000000;
            ts.tv_sec++;
        }
        /* Note! No need to complete uAbsTimeout for RTSEMWAIT_FLAGS_RELATIVE in this path. */
    }
    else
    {
        /* ASSUMES RTTimeSystemNanoTS() == RTTimeNanoTS() == clock_gettime(CLOCK_MONOTONIC). */
        if (fFlags & RTSEMWAIT_FLAGS_RELATIVE)
            uAbsTimeout += RTTimeSystemNanoTS();
        if (   sizeof(ts.tv_sec) < sizeof(uint64_t)
            && uAbsTimeout > UINT64_C(1000000000) * UINT32_MAX)
            return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);
        ts.tv_nsec = uAbsTimeout % UINT32_C(1000000000);
        ts.tv_sec  = uAbsTimeout / UINT32_C(1000000000);
    }

    /*
     * To business!
     */
    /* take mutex */
    int rc = pthread_mutex_lock(&pThis->Mutex);
    AssertMsgReturn(rc == 0, ("rc=%d pThis=%p\n", rc, pThis), RTErrConvertFromErrno(rc)); NOREF(rc);
    ASMAtomicIncU32(&pThis->cWaiters);

    for (;;)
    {
        /* check state. */
        uint32_t const u32State = pThis->u32State;
        if (u32State != EVENTMULTI_STATE_NOT_SIGNALED)
        {
            ASMAtomicDecU32(&pThis->cWaiters);
            rc = pthread_mutex_unlock(&pThis->Mutex);
            AssertMsg(!rc, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc));
            return u32State == EVENTMULTI_STATE_SIGNALED
                 ? VINF_SUCCESS
                 : VERR_SEM_DESTROYED;
        }

        /* wait */
#ifdef RTSEMEVENTMULTI_STRICT
        RTTHREAD hThreadSelf = RTThreadSelfAutoAdopt();
        if (pThis->fEverHadSignallers)
        {
            rc = RTLockValidatorRecSharedCheckBlocking(&pThis->Signallers, hThreadSelf, pSrcPos, false,
                                                       uTimeout / UINT32_C(1000000), RTTHREADSTATE_EVENT_MULTI, true);
            if (RT_FAILURE(rc))
            {
                ASMAtomicDecU32(&pThis->cWaiters);
                pthread_mutex_unlock(&pThis->Mutex);
                return rc;
            }
        }
#else
        RTTHREAD hThreadSelf = RTThreadSelf();
#endif
        RTThreadBlocking(hThreadSelf, RTTHREADSTATE_EVENT_MULTI, true);
        rc = pthread_cond_timedwait(&pThis->Cond, &pThis->Mutex, &ts);
        RTThreadUnblocked(hThreadSelf, RTTHREADSTATE_EVENT_MULTI);
        if (    rc
            && (   rc != EINTR  /* according to SuS this function shall not return EINTR, but linux man page says differently. */
                || (fFlags & RTSEMWAIT_FLAGS_NORESUME)) )
        {
            AssertMsg(rc == ETIMEDOUT, ("Failed to wait on event multi sem %p, rc=%d.\n", pThis, rc));
            ASMAtomicDecU32(&pThis->cWaiters);
            int rc2 = pthread_mutex_unlock(&pThis->Mutex);
            AssertMsg(!rc2, ("Failed to unlock event multi sem %p, rc=%d.\n", pThis, rc2)); NOREF(rc2);
            return RTErrConvertFromErrno(rc);
        }

        /* check the absolute deadline. */
    }
}


DECLINLINE(int) rtSemEventMultiPosixWait(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
                                         PCRTLOCKVALSRCPOS pSrcPos)
{
    /*
     * Validate input.
     */
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
    uint32_t u32 = pThis->u32State;
    AssertReturn(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED, VERR_INVALID_HANDLE);
    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);

    /*
     * Optimize the case where the event is signalled.
     */
    if (ASMAtomicUoReadU32(&pThis->u32State) == EVENTMULTI_STATE_SIGNALED)
    {
        int rc = rtSemEventMultiPosixWaitPoll(pThis);
        if (RT_LIKELY(rc != VERR_TIMEOUT))
            return rc;
    }

    /*
     * Indefinite or timed wait?
     */
    if (fFlags & RTSEMWAIT_FLAGS_INDEFINITE)
        return rtSemEventMultiPosixWaitIndefinite(pThis, fFlags, pSrcPos);
    return rtSemEventMultiPosixWaitTimed(pThis, fFlags, uTimeout, pSrcPos);
}


#undef RTSemEventMultiWaitEx
RTDECL(int)  RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout)
{
#ifndef RTSEMEVENT_STRICT
    return rtSemEventMultiPosixWait(hEventMultiSem, fFlags, uTimeout, NULL);
#else
    RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
    return rtSemEventMultiPosixWait(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 rtSemEventMultiPosixWait(hEventMultiSem, fFlags, uTimeout, &SrcPos);
}


RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
{
#ifdef RTSEMEVENTMULTI_STRICT
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    AssertPtrReturnVoid(pThis);
    uint32_t u32 = pThis->u32State;
    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);

    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
    RTLockValidatorRecSharedResetOwner(&pThis->Signallers, hThread, NULL);
#else
    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
#endif
}


RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
{
#ifdef RTSEMEVENTMULTI_STRICT
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    AssertPtrReturnVoid(pThis);
    uint32_t u32 = pThis->u32State;
    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);

    ASMAtomicWriteBool(&pThis->fEverHadSignallers, true);
    RTLockValidatorRecSharedAddOwner(&pThis->Signallers, hThread, NULL);
#else
    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
#endif
}


RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread)
{
#ifdef RTSEMEVENTMULTI_STRICT
    struct RTSEMEVENTMULTIINTERNAL *pThis = hEventMultiSem;
    AssertPtrReturnVoid(pThis);
    uint32_t u32 = pThis->u32State;
    AssertReturnVoid(u32 == EVENTMULTI_STATE_NOT_SIGNALED || u32 == EVENTMULTI_STATE_SIGNALED);

    RTLockValidatorRecSharedRemoveOwner(&pThis->Signallers, hThread);
#else
    RT_NOREF_PV(hEventMultiSem); RT_NOREF_PV(hThread);
#endif
}