/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* * The contents of this file are subject to the Netscape Public License * Version 1.0 (the "NPL"); you may not use this file except in * compliance with the NPL. You may obtain a copy of the NPL at * http://www.mozilla.org/NPL/ * * Software distributed under the NPL is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL * for the specific language governing rights and limitations under the * NPL. * * The Initial Developer of this code under the NPL is Netscape * Communications Corporation. Portions created by Netscape are * Copyright (C) 1998 Netscape Communications Corporation. All Rights * Reserved. */ /* ** File: ptsynch.c ** Descritpion: Implemenation for thread synchronization using pthreads ** Exports: prlock.h, prcvar.h, prmon.h, prcmon.h */ #if defined(_PR_PTHREADS) #include "primpl.h" #include "obsolete/prsem.h" #include #include #include static pthread_mutexattr_t _pt_mattr; static pthread_condattr_t _pt_cvar_attr; #if defined(DEBUG) extern PTDebug pt_debug; /* this is shared between several modules */ #if defined(_PR_DCETHREADS) static pthread_t pt_zero_tid; /* a null pthread_t (pthread_t is a struct * in DCE threads) to compare with */ #endif /* defined(_PR_DCETHREADS) */ #endif /* defined(DEBUG) */ /**************************************************************/ /**************************************************************/ /*****************************LOCKS****************************/ /**************************************************************/ /**************************************************************/ void _PR_InitLocks(void) { int rv; rv = PTHREAD_MUTEXATTR_INIT(&_pt_mattr); PR_ASSERT(0 == rv); #if defined(AIX) rv = pthread_mutexattr_setkind_np(&_pt_mattr, MUTEX_FAST_NP); PR_ASSERT(0 == rv); #endif rv = PTHREAD_CONDATTR_INIT(&_pt_cvar_attr); PR_ASSERT(0 == rv); _PR_MD_INIT_LOCKS(); } static void pt_PostNotifies(PRLock *lock, PRBool unlock) { PRIntn index, rv; _PT_Notified post; _PT_Notified *notified, *prev = NULL; /* * Time to actually notify any conditions that were affected * while the lock was held. Get a copy of the list that's in * the lock structure and then zero the original. If it's * linked to other such structures, we own that storage. */ post = lock->notified; /* a safe copy; we own the lock */ #if defined(DEBUG) memset(&lock->notified, 0, sizeof(_PT_Notified)); /* reset */ #else lock->notified.length = 0; /* these are really sufficient */ lock->notified.link = NULL; #endif /* should (may) we release lock before notifying? */ if (unlock) { rv = pthread_mutex_unlock(&lock->mutex); PR_ASSERT(0 == rv); } notified = &post; /* this is where we start */ do { for (index = 0; index < notified->length; ++index) { PRCondVar *cv = notified->cv[index].cv; PR_ASSERT(NULL != cv); PR_ASSERT(0 != notified->cv[index].times); if (-1 == notified->cv[index].times) { rv = pthread_cond_broadcast(&cv->cv); PR_ASSERT(0 == rv); } else { while (notified->cv[index].times-- > 0) { rv = pthread_cond_signal(&cv->cv); PR_ASSERT((0 == rv) || (EINVAL == rv)); } } #if defined(DEBUG) pt_debug.cvars_notified += 1; if (0 > PR_AtomicDecrement(&cv->notify_pending)) { pt_debug.delayed_cv_deletes += 1; PR_DestroyCondVar(cv); } #else /* defined(DEBUG) */ if (0 > PR_AtomicDecrement(&cv->notify_pending)) PR_DestroyCondVar(cv); #endif /* defined(DEBUG) */ } prev = notified; notified = notified->link; if (&post != prev) PR_DELETE(prev); } while (NULL != notified); } /* pt_PostNotifies */ PR_IMPLEMENT(PRLock*) PR_NewLock(void) { PRIntn rv; PRLock *lock; if (!_pr_initialized) _PR_ImplicitInitialization(); lock = PR_NEWZAP(PRLock); if (lock != NULL) { rv = PTHREAD_MUTEX_INIT(lock->mutex, _pt_mattr); PR_ASSERT(0 == rv); } #if defined(DEBUG) pt_debug.locks_created += 1; #endif return lock; } /* PR_NewLock */ PR_IMPLEMENT(void) PR_DestroyLock(PRLock *lock) { PRIntn rv; PR_ASSERT(NULL != lock); PR_ASSERT(PTHREAD_THR_HANDLE_IS_ZERO(lock->owner)); PR_ASSERT(0 == lock->notified.length); PR_ASSERT(NULL == lock->notified.link); rv = pthread_mutex_destroy(&lock->mutex); PR_ASSERT(0 == rv); #if defined(DEBUG) memset(lock, 0xaf, sizeof(PRLock)); pt_debug.locks_destroyed += 1; #endif PR_DELETE(lock); } /* PR_DestroyLock */ PR_IMPLEMENT(void) PR_Lock(PRLock *lock) { PRIntn rv; PR_ASSERT(lock != NULL); rv = pthread_mutex_lock(&lock->mutex); PR_ASSERT(0 == rv); PR_ASSERT(0 == lock->notified.length); PR_ASSERT(NULL == lock->notified.link); PR_ASSERT(PTHREAD_THR_HANDLE_IS_ZERO(lock->owner)); PTHREAD_COPY_THR_HANDLE(pthread_self(), lock->owner); #if defined(DEBUG) pt_debug.locks_acquired += 1; #endif } /* PR_Lock */ PR_IMPLEMENT(PRStatus) PR_Unlock(PRLock *lock) { PRIntn rv; PR_ASSERT(lock != NULL); PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(lock->mutex)); PR_ASSERT(pthread_equal(lock->owner, pthread_self())); if (!pthread_equal(lock->owner, pthread_self())) return PR_FAILURE; PTHREAD_ZERO_THR_HANDLE(lock->owner); if (0 == lock->notified.length) /* shortcut */ { rv = pthread_mutex_unlock(&lock->mutex); PR_ASSERT(0 == rv); } else pt_PostNotifies(lock, PR_TRUE); #if defined(DEBUG) pt_debug.locks_released += 1; #endif return PR_SUCCESS; } /* PR_Unlock */ /**************************************************************/ /**************************************************************/ /***************************CONDITIONS*************************/ /**************************************************************/ /**************************************************************/ /* * This code is used to compute the absolute time for the wakeup. * It's moderately ugly, so it's defined here and called in a * couple of places. */ #define PT_NANOPERMICRO 1000UL #define PT_BILLION 1000000000UL static PRIntn pt_TimedWait( pthread_cond_t *cv, pthread_mutex_t *ml, PRIntervalTime timeout) { int rv; struct timeval now; struct timespec tmo; PRUint32 ticks = PR_TicksPerSecond(); tmo.tv_sec = (PRInt32)(timeout / ticks); tmo.tv_nsec = (PRInt32)(timeout - (tmo.tv_sec * ticks)); tmo.tv_nsec = (PRInt32)PR_IntervalToMicroseconds(PT_NANOPERMICRO * tmo.tv_nsec); /* pthreads wants this in absolute time, off we go ... */ (void)GETTIMEOFDAY(&now); /* that one's usecs, this one's nsecs - grrrr! */ tmo.tv_sec += now.tv_sec; tmo.tv_nsec += (PT_NANOPERMICRO * now.tv_usec); tmo.tv_sec += tmo.tv_nsec / PT_BILLION; tmo.tv_nsec %= PT_BILLION; rv = pthread_cond_timedwait(cv, ml, &tmo); /* NSPR doesn't report timeouts */ #ifdef _PR_DCETHREADS return (rv == -1 && errno == EAGAIN) ? 0 : rv; #else return (rv == ETIMEDOUT) ? 0 : rv; #endif } /* pt_TimedWait */ /* * Notifies just get posted to the to the protecting mutex. The * actual notification is done when the lock is released so that * MP systems don't contend for a lock that they can't have. */ static void pt_PostNotifyToCvar(PRCondVar *cvar, PRBool broadcast) { PRIntn index = 0; _PT_Notified *notified = &cvar->lock->notified; PR_ASSERT(pthread_equal(cvar->lock->owner, pthread_self())); PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(cvar->lock->mutex)); while (1) { for (index = 0; index < notified->length; ++index) { if (notified->cv[index].cv == cvar) { if (broadcast) notified->cv[index].times = -1; else if (-1 != notified->cv[index].times) notified->cv[index].times += 1; goto finished; /* we're finished */ } } /* if not full, enter new CV in this array */ if (notified->length < PT_CV_NOTIFIED_LENGTH) break; /* if there's no link, create an empty array and link it */ if (NULL == notified->link) notified->link = PR_NEWZAP(_PT_Notified); notified = notified->link; } /* A brand new entry in the array */ (void)PR_AtomicIncrement(&cvar->notify_pending); notified->cv[index].times = (broadcast) ? -1 : 1; notified->cv[index].cv = cvar; notified->length += 1; finished: PR_ASSERT(pthread_equal(cvar->lock->owner, pthread_self())); } /* pt_PostNotifyToCvar */ PR_IMPLEMENT(PRCondVar*) PR_NewCondVar(PRLock *lock) { PRCondVar *cv = PR_NEW(PRCondVar); PR_ASSERT(lock != NULL); if (cv != NULL) { int rv = PTHREAD_COND_INIT(cv->cv, _pt_cvar_attr); PR_ASSERT(0 == rv); cv->lock = lock; cv->notify_pending = 0; #if defined(DEBUG) pt_debug.cvars_created += 1; #endif } return cv; } /* PR_NewCondVar */ PR_IMPLEMENT(void) PR_DestroyCondVar(PRCondVar *cvar) { if (0 > PR_AtomicDecrement(&cvar->notify_pending)) { PRIntn rv = pthread_cond_destroy(&cvar->cv); PR_ASSERT(0 == rv); #if defined(DEBUG) memset(cvar, 0xaf, sizeof(PRCondVar)); pt_debug.cvars_destroyed += 1; #endif PR_DELETE(cvar); } } /* PR_DestroyCondVar */ PR_IMPLEMENT(PRStatus) PR_WaitCondVar(PRCondVar *cvar, PRIntervalTime timeout) { PRIntn rv; PRThread *thred = PR_CurrentThread(); PR_ASSERT(cvar != NULL); /* We'd better be locked */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(cvar->lock->mutex)); /* and it better be by us */ PR_ASSERT(pthread_equal(cvar->lock->owner, pthread_self())); if (thred->state & PT_THREAD_ABORTED) goto aborted; /* * The thread waiting is used for PR_Interrupt */ thred->waiting = cvar; /* this is where we're waiting */ /* * If we have pending notifies, post them now. * * This is not optimal. We're going to post these notifies * while we're holding the lock. That means on MP systems * that they are going to collide for the lock that we will * hold until we actually wait. */ if (0 != cvar->lock->notified.length) pt_PostNotifies(cvar->lock, PR_FALSE); /* * We're surrendering the lock, so clear out the owner field. */ PTHREAD_ZERO_THR_HANDLE(cvar->lock->owner); if (timeout == PR_INTERVAL_NO_TIMEOUT) rv = pthread_cond_wait(&cvar->cv, &cvar->lock->mutex); else rv = pt_TimedWait(&cvar->cv, &cvar->lock->mutex, timeout); /* We just got the lock back - this better be empty */ PR_ASSERT(PTHREAD_THR_HANDLE_IS_ZERO(cvar->lock->owner)); PTHREAD_COPY_THR_HANDLE(pthread_self(), cvar->lock->owner); PR_ASSERT(0 == cvar->lock->notified.length); thred->waiting = NULL; /* and now we're not */ if (thred->state & PT_THREAD_ABORTED) goto aborted; return (rv == 0) ? PR_SUCCESS : PR_FAILURE; aborted: PR_SetError(PR_PENDING_INTERRUPT_ERROR, 0); thred->state &= ~PT_THREAD_ABORTED; return PR_FAILURE; } /* PR_WaitCondVar */ PR_IMPLEMENT(PRStatus) PR_NotifyCondVar(PRCondVar *cvar) { PR_ASSERT(cvar != NULL); pt_PostNotifyToCvar(cvar, PR_FALSE); return PR_SUCCESS; } /* PR_NotifyCondVar */ PR_IMPLEMENT(PRStatus) PR_NotifyAllCondVar(PRCondVar *cvar) { PR_ASSERT(cvar != NULL); pt_PostNotifyToCvar(cvar, PR_TRUE); return PR_SUCCESS; } /* PR_NotifyAllCondVar */ /**************************************************************/ /**************************************************************/ /***************************MONITORS***************************/ /**************************************************************/ /**************************************************************/ PR_IMPLEMENT(PRMonitor*) PR_NewMonitor(void) { PRMonitor *mon; PRCondVar *cvar; if (!_pr_initialized) _PR_ImplicitInitialization(); cvar = PR_NEWZAP(PRCondVar); if (NULL == cvar) { PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); return NULL; } mon = PR_NEWZAP(PRMonitor); if (mon != NULL) { int rv; rv = PTHREAD_MUTEX_INIT(mon->lock.mutex, _pt_mattr); PR_ASSERT(0 == rv); mon->cvar = cvar; rv = PTHREAD_COND_INIT(mon->cvar->cv, _pt_cvar_attr); PR_ASSERT(0 == rv); mon->entryCount = 0; mon->cvar->lock = &mon->lock; if (0 != rv) { PR_DELETE(mon); PR_DELETE(cvar); mon = NULL; } } return mon; } /* PR_NewMonitor */ PR_IMPLEMENT(PRMonitor*) PR_NewNamedMonitor(const char* name) { PRMonitor* mon = PR_NewMonitor(); mon->name = name; return mon; } PR_IMPLEMENT(void) PR_DestroyMonitor(PRMonitor *mon) { int rv; PR_ASSERT(mon != NULL); PR_DestroyCondVar(mon->cvar); rv = pthread_mutex_destroy(&mon->lock.mutex); PR_ASSERT(0 == rv); #if defined(DEBUG) memset(mon, 0xaf, sizeof(PRMonitor)); #endif PR_DELETE(mon); } /* PR_DestroyMonitor */ /* The GC uses this; it is quite arguably a bad interface. I'm just * duplicating it for now - XXXMB */ PR_IMPLEMENT(PRInt32) PR_GetMonitorEntryCount(PRMonitor *mon) { pthread_t self = pthread_self(); if (pthread_equal(mon->owner, self)) return mon->entryCount; return 0; } PR_IMPLEMENT(void) PR_EnterMonitor(PRMonitor *mon) { int rv; pthread_t self = pthread_self(); PR_ASSERT(mon != NULL); rv = pthread_mutex_trylock(&mon->lock.mutex); #ifdef _PR_DCETHREADS if (1 == rv) #else if (0 == rv) #endif { /* I now have the lock - I can play in the sandbox */ /* could/should/would not have gotten lock if entries != 0 */ PR_ASSERT(0 == mon->entryCount); PR_ASSERT(PTHREAD_THR_HANDLE_IS_ZERO(mon->lock.owner)); PTHREAD_COPY_THR_HANDLE(pthread_self(), mon->lock.owner); PTHREAD_COPY_THR_HANDLE(self, mon->owner); } else { PR_ASSERT(PT_TRYLOCK_BUSY == rv); /* and if it isn't? */ /* somebody has it locked - is it me? */ if (!pthread_equal(mon->owner, self)) { /* it's not me - this should block */ PR_Lock(&mon->lock); /* and now I have the lock */ PR_ASSERT(0 == mon->entryCount); PTHREAD_COPY_THR_HANDLE(self, mon->owner); } } mon->entryCount += 1; } /* PR_EnterMonitor */ PR_IMPLEMENT(PRStatus) PR_ExitMonitor(PRMonitor *mon) { pthread_t self = pthread_self(); PR_ASSERT(mon != NULL); /* The lock better be that - locked */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(mon->lock.mutex)); /* we'd better be the owner */ PR_ASSERT(pthread_equal(mon->owner, self)); if (!pthread_equal(mon->owner, self)) return PR_FAILURE; /* if it's locked and we have it, then the entries should be > 0 */ PR_ASSERT(mon->entryCount > 0); mon->entryCount -= 1; /* reduce by one */ if (mon->entryCount == 0) { /* and if it transitioned to zero - unlock */ PTHREAD_ZERO_THR_HANDLE(mon->owner); /* make the owner unknown */ PR_Unlock(&mon->lock); } return PR_SUCCESS; } /* PR_ExitMonitor */ PR_IMPLEMENT(PRStatus) PR_Wait(PRMonitor *mon, PRIntervalTime timeout) { PRStatus rv; PRInt16 saved_entries; pthread_t saved_owner; PR_ASSERT(mon != NULL); /* we'd better be locked */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(mon->lock.mutex)); /* and the entries better be positive */ PR_ASSERT(mon->entryCount > 0); /* and it better be by us */ PR_ASSERT(pthread_equal(mon->owner, pthread_self())); /* tuck these away 'till later */ saved_entries = mon->entryCount; mon->entryCount = 0; PTHREAD_COPY_THR_HANDLE(mon->owner, saved_owner); PTHREAD_ZERO_THR_HANDLE(mon->owner); rv = PR_WaitCondVar(mon->cvar, timeout); /* reinstate the intresting information */ mon->entryCount = saved_entries; PTHREAD_COPY_THR_HANDLE(saved_owner, mon->owner); return rv; } /* PR_Wait */ PR_IMPLEMENT(PRStatus) PR_Notify(PRMonitor *mon) { PR_ASSERT(NULL != mon); /* we'd better be locked */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(mon->lock.mutex)); /* and the entries better be positive */ PR_ASSERT(mon->entryCount > 0); /* and it better be by us */ PR_ASSERT(pthread_equal(mon->owner, pthread_self())); pt_PostNotifyToCvar(mon->cvar, PR_FALSE); return PR_SUCCESS; } /* PR_Notify */ PR_IMPLEMENT(PRStatus) PR_NotifyAll(PRMonitor *mon) { PR_ASSERT(mon != NULL); /* we'd better be locked */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(mon->lock.mutex)); /* and the entries better be positive */ PR_ASSERT(mon->entryCount > 0); /* and it better be by us */ PR_ASSERT(pthread_equal(mon->owner, pthread_self())); pt_PostNotifyToCvar(mon->cvar, PR_TRUE); return PR_SUCCESS; } /* PR_NotifyAll */ /**************************************************************/ /**************************************************************/ /**************************SEMAPHORES**************************/ /**************************************************************/ /**************************************************************/ PR_IMPLEMENT(void) PR_PostSem(PRSemaphore *semaphore) { static PRBool unwarned = PR_TRUE; if (unwarned) unwarned = _PR_Obsolete( "PR_PostSem", "locks & condition variables"); PR_Lock(semaphore->cvar->lock); PR_NotifyCondVar(semaphore->cvar); semaphore->count += 1; PR_Unlock(semaphore->cvar->lock); } /* PR_PostSem */ PR_IMPLEMENT(PRStatus) PR_WaitSem(PRSemaphore *semaphore) { PRStatus status = PR_SUCCESS; static PRBool unwarned = PR_TRUE; if (unwarned) unwarned = _PR_Obsolete( "PR_WaitSem", "locks & condition variables"); PR_Lock(semaphore->cvar->lock); while ((semaphore->count == 0) && (PR_SUCCESS == status)) status = PR_WaitCondVar(semaphore->cvar, PR_INTERVAL_NO_TIMEOUT); if (PR_SUCCESS == status) semaphore->count -= 1; PR_Unlock(semaphore->cvar->lock); return status; } /* PR_WaitSem */ PR_IMPLEMENT(void) PR_DestroySem(PRSemaphore *semaphore) { static PRBool unwarned = PR_TRUE; if (unwarned) unwarned = _PR_Obsolete( "PR_DestroySem", "locks & condition variables"); PR_DestroyLock(semaphore->cvar->lock); PR_DestroyCondVar(semaphore->cvar); PR_DELETE(semaphore); } /* PR_DestroySem */ PR_IMPLEMENT(PRSemaphore*) PR_NewSem(PRUintn value) { PRSemaphore *semaphore; static PRBool unwarned = PR_TRUE; if (!_pr_initialized) _PR_ImplicitInitialization(); if (unwarned) unwarned = _PR_Obsolete( "PR_NewSem", "locks & condition variables"); semaphore = PR_NEWZAP(PRSemaphore); if (NULL != semaphore) { PRLock *lock = PR_NewLock(); if (NULL != lock) { semaphore->cvar = PR_NewCondVar(lock); if (NULL != semaphore->cvar) { semaphore->count = value; return semaphore; } PR_DestroyLock(lock); } PR_DELETE(semaphore); } return NULL; } /**************************************************************/ /**************************************************************/ /******************ROUTINES FOR DCE EMULATION******************/ /**************************************************************/ /**************************************************************/ #include "prpdce.h" PR_IMPLEMENT(PRStatus) PRP_TryLock(PRLock *lock) { PRIntn rv = pthread_mutex_trylock(&lock->mutex); if (rv == PT_TRYLOCK_SUCCESS) { PR_ASSERT(PTHREAD_THR_HANDLE_IS_ZERO(lock->owner)); PTHREAD_COPY_THR_HANDLE(pthread_self(), lock->owner); } else PR_ASSERT(!PTHREAD_THR_HANDLE_IS_ZERO(lock->owner)); /* XXX set error code? */ return (PT_TRYLOCK_SUCCESS == rv) ? PR_SUCCESS : PR_FAILURE; } /* PRP_TryLock */ PR_IMPLEMENT(PRCondVar*) PRP_NewNakedCondVar() { PRCondVar *cv; if (!_pr_initialized) _PR_ImplicitInitialization(); cv = PR_NEW(PRCondVar); if (cv != NULL) { int rv; rv = PTHREAD_COND_INIT(cv->cv, _pt_cvar_attr); PR_ASSERT(0 == rv); cv->lock = _PR_NAKED_CV_LOCK; } return cv; } /* PRP_NewNakedCondVar */ PR_IMPLEMENT(void) PRP_DestroyNakedCondVar(PRCondVar *cvar) { int rv; rv = pthread_cond_destroy(&cvar->cv); PR_ASSERT(0 == rv); #if defined(DEBUG) memset(cvar, 0xaf, sizeof(PRCondVar)); #endif PR_DELETE(cvar); } /* PRP_DestroyNakedCondVar */ PR_IMPLEMENT(PRStatus) PRP_NakedWait( PRCondVar *cvar, PRLock *ml, PRIntervalTime timeout) { PRIntn rv; PR_ASSERT(cvar != NULL); /* XXX do we really want to assert this in a naked wait? */ PR_ASSERT(PTHREAD_MUTEX_IS_LOCKED(ml->mutex)); if (timeout == PR_INTERVAL_NO_TIMEOUT) rv = pthread_cond_wait(&cvar->cv, &ml->mutex); else rv = pt_TimedWait(&cvar->cv, &ml->mutex, timeout); return (rv == 0) ? PR_SUCCESS : PR_FAILURE; } /* PRP_NakedWait */ PR_IMPLEMENT(PRStatus) PRP_NakedNotify(PRCondVar *cvar) { int rv; PR_ASSERT(cvar != NULL); rv = pthread_cond_signal(&cvar->cv); PR_ASSERT(0 == rv); return PR_SUCCESS; } /* PRP_NakedNotify */ PR_IMPLEMENT(PRStatus) PRP_NakedBroadcast(PRCondVar *cvar) { int rv; PR_ASSERT(cvar != NULL); rv = pthread_cond_broadcast(&cvar->cv); PR_ASSERT(0 == rv); return PR_SUCCESS; } /* PRP_NakedBroadcast */ #endif /* defined(_PR_PTHREADS) */ /* ptsynch.c */