/* * tclUnixThrd.c -- * * This file implements the UNIX-specific thread support. * * Copyright © 1991-1994 The Regents of the University of California. * Copyright © 1994-1997 Sun Microsystems, Inc. * Copyright © 2008 George Peter Staplin * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. */ #include "tclInt.h" #if TCL_THREADS /* * TIP #509. Ensures that Tcl's mutexes are reentrant. * *---------------------------------------------------------------------- * * PMutexInit -- * * Sets up the memory pointed to by its argument so that it contains the * implementation of a recursive lock. Caller supplies the space. * *---------------------------------------------------------------------- * * PMutexDestroy -- * * Tears down the implementation of a recursive lock (but does not * deallocate the space holding the lock). * *---------------------------------------------------------------------- * * PMutexLock -- * * Locks a recursive lock. (Similar to pthread_mutex_lock) * *---------------------------------------------------------------------- * * PMutexUnlock -- * * Unlocks a recursive lock. (Similar to pthread_mutex_unlock) * *---------------------------------------------------------------------- * * PCondWait -- * * Waits on a condition variable linked a recursive lock. (Similar to * pthread_cond_wait) * *---------------------------------------------------------------------- * * PCondTimedWait -- * * Waits for a limited amount of time on a condition variable linked to a * recursive lock. (Similar to pthread_cond_timedwait) * *---------------------------------------------------------------------- */ #ifndef HAVE_DECL_PTHREAD_MUTEX_RECURSIVE #define HAVE_DECL_PTHREAD_MUTEX_RECURSIVE 0 #endif #if HAVE_DECL_PTHREAD_MUTEX_RECURSIVE /* * Pthread has native reentrant (AKA recursive) mutexes. Use them for * Tcl_Mutex. */ typedef pthread_mutex_t PMutex; static void PMutexInit( PMutex *pmutexPtr) { pthread_mutexattr_t attr; pthread_mutexattr_init(&attr); pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); pthread_mutex_init(pmutexPtr, &attr); } #define PMutexDestroy pthread_mutex_destroy #define PMutexLock pthread_mutex_lock #define PMutexUnlock pthread_mutex_unlock #define PCondWait pthread_cond_wait #define PCondTimedWait pthread_cond_timedwait #else /* !HAVE_PTHREAD_MUTEX_RECURSIVE */ /* * No native support for reentrant mutexes. Emulate them with regular mutexes * and thread-local counters. */ typedef struct PMutex { pthread_mutex_t mutex; pthread_t thread; int counter; } PMutex; static void PMutexInit( PMutex *pmutexPtr) { pthread_mutex_init(&pmutexPtr->mutex, NULL); pmutexPtr->thread = 0; pmutexPtr->counter = 0; } static void PMutexDestroy( PMutex *pmutexPtr) { pthread_mutex_destroy(&pmutexPtr->mutex); } static void PMutexLock( PMutex *pmutexPtr) { if (pmutexPtr->thread != pthread_self() || pmutexPtr->counter == 0) { pthread_mutex_lock(&pmutexPtr->mutex); pmutexPtr->thread = pthread_self(); pmutexPtr->counter = 0; } pmutexPtr->counter++; } static void PMutexUnlock( PMutex *pmutexPtr) { pmutexPtr->counter--; if (pmutexPtr->counter == 0) { pmutexPtr->thread = 0; pthread_mutex_unlock(&pmutexPtr->mutex); } } static void PCondWait( pthread_cond_t *pcondPtr, PMutex *pmutexPtr) { pthread_cond_wait(pcondPtr, &pmutexPtr->mutex); } static void PCondTimedWait( pthread_cond_t *pcondPtr, PMutex *pmutexPtr, struct timespec *ptime) { pthread_cond_timedwait(pcondPtr, &pmutexPtr->mutex, ptime); } #endif /* HAVE_PTHREAD_MUTEX_RECURSIVE */ #ifndef TCL_NO_DEPRECATED typedef struct { char nabuf[16]; } ThreadSpecificData; static Tcl_ThreadDataKey dataKey; #endif /* TCL_NO_DEPRECATED */ /* * globalLock is used to serialize creation of mutexes, condition variables, * and thread local storage. This is the only place that can count on the * ability to statically initialize the mutex. */ static pthread_mutex_t globalLock = PTHREAD_MUTEX_INITIALIZER; /* * initLock is used to serialize initialization and finalization of Tcl. It * cannot use any dynamically allocated storage. */ static pthread_mutex_t initLock = PTHREAD_MUTEX_INITIALIZER; /* * allocLock is used by Tcl's version of malloc for synchronization. For * obvious reasons, cannot use any dynamically allocated storage. */ static PMutex allocLock; static pthread_once_t allocLockInitOnce = PTHREAD_ONCE_INIT; static void allocLockInit(void) { PMutexInit(&allocLock); } static PMutex *allocLockPtr = &allocLock; #endif /* TCL_THREADS */ /* *---------------------------------------------------------------------- * * TclpThreadCreate -- * * This procedure creates a new thread. * * Results: * TCL_OK if the thread could be created. The thread ID is returned in a * parameter. * * Side effects: * A new thread is created. * *---------------------------------------------------------------------- */ int TclpThreadCreate( Tcl_ThreadId *idPtr, /* Return, the ID of the thread */ Tcl_ThreadCreateProc *proc, /* Main() function of the thread */ void *clientData, /* The one argument to Main() */ TCL_HASH_TYPE stackSize, /* Size of stack for the new thread */ int flags) /* Flags controlling behaviour of the new * thread. */ { #if TCL_THREADS pthread_attr_t attr; pthread_t theThread; int result; pthread_attr_init(&attr); pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM); #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE if (stackSize != TCL_THREAD_STACK_DEFAULT) { pthread_attr_setstacksize(&attr, (size_t)stackSize); #ifdef TCL_THREAD_STACK_MIN } else { /* * Certain systems define a thread stack size that by default is too * small for many operations. The user has the option of defining * TCL_THREAD_STACK_MIN to a value large enough to work for their * needs. This would look like (for 128K min stack): * make MEM_DEBUG_FLAGS=-DTCL_THREAD_STACK_MIN=131072L * * This solution is not optimal, as we should allow the user to * specify a size at runtime, but we don't want to slow this function * down, and that would still leave the main thread at the default. */ size_t size; result = pthread_attr_getstacksize(&attr, &size); if (!result && (size < TCL_THREAD_STACK_MIN)) { pthread_attr_setstacksize(&attr, (size_t)TCL_THREAD_STACK_MIN); } #endif /* TCL_THREAD_STACK_MIN */ } #endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */ if (!(flags & TCL_THREAD_JOINABLE)) { pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); } if (pthread_create(&theThread, &attr, (void * (*)(void *))(void *)proc, (void *)clientData) && pthread_create(&theThread, NULL, (void * (*)(void *))(void *)proc, (void *)clientData)) { result = TCL_ERROR; } else { *idPtr = (Tcl_ThreadId)theThread; result = TCL_OK; } pthread_attr_destroy(&attr); return result; #else (void)idPtr; (void)proc; (void)clientData; (void)stackSize; (void)flags; return TCL_ERROR; #endif /* TCL_THREADS */ } /* *---------------------------------------------------------------------- * * Tcl_JoinThread -- * * This procedure waits upon the exit of the specified thread. * * Results: * TCL_OK if the wait was successful, TCL_ERROR else. * * Side effects: * The result area is set to the exit code of the thread we waited upon. * *---------------------------------------------------------------------- */ int Tcl_JoinThread( Tcl_ThreadId threadId, /* Id of the thread to wait upon. */ int *state) /* Reference to the storage the result of the * thread we wait upon will be written into. * May be NULL. */ { #if TCL_THREADS int result; unsigned long retcode, *retcodePtr = &retcode; result = pthread_join((pthread_t) threadId, (void**) retcodePtr); if (state) { *state = (int) retcode; } return (result == 0) ? TCL_OK : TCL_ERROR; #else (void)threadId; (void)state; return TCL_ERROR; #endif } /* *---------------------------------------------------------------------- * * TclpThreadExit -- * * This procedure terminates the current thread. * * Results: * None. * * Side effects: * This procedure terminates the current thread. * *---------------------------------------------------------------------- */ TCL_NORETURN void TclpThreadExit( int status) { #if TCL_THREADS pthread_exit(INT2PTR(status)); #else /* TCL_THREADS */ exit(status); #endif /* TCL_THREADS */ } /* *---------------------------------------------------------------------- * * Tcl_GetCurrentThread -- * * This procedure returns the ID of the currently running thread. * * Results: * A thread ID. * * Side effects: * None. * *---------------------------------------------------------------------- */ Tcl_ThreadId Tcl_GetCurrentThread(void) { #if TCL_THREADS return (Tcl_ThreadId) pthread_self(); #else return (Tcl_ThreadId) 0; #endif } /* *---------------------------------------------------------------------- * * TclpInitLock * * This procedure is used to grab a lock that serializes initialization * and finalization of Tcl. On some platforms this may also initialize * the mutex used to serialize creation of more mutexes and thread local * storage keys. * * Results: * None. * * Side effects: * Acquire the initialization mutex. * *---------------------------------------------------------------------- */ void TclpInitLock(void) { #if TCL_THREADS pthread_mutex_lock(&initLock); #endif } /* *---------------------------------------------------------------------- * * TclFinalizeLock * * This procedure is used to destroy all private resources used in this * file. * * Results: * None. * * Side effects: * Destroys everything private. TclpInitLock must be held entering this * function. * *---------------------------------------------------------------------- */ void TclFinalizeLock(void) { #if TCL_THREADS /* * You do not need to destroy mutexes that were created with the * PTHREAD_MUTEX_INITIALIZER macro. These mutexes do not need any * destruction: globalLock, allocLock, and initLock. */ pthread_mutex_unlock(&initLock); #endif } /* *---------------------------------------------------------------------- * * TclpInitUnlock * * This procedure is used to release a lock that serializes * initialization and finalization of Tcl. * * Results: * None. * * Side effects: * Release the initialization mutex. * *---------------------------------------------------------------------- */ void TclpInitUnlock(void) { #if TCL_THREADS pthread_mutex_unlock(&initLock); #endif } /* *---------------------------------------------------------------------- * * TclpGlobalLock * * This procedure is used to grab a lock that serializes creation and * finalization of serialization objects. This interface is only needed * in finalization; it is hidden during creation of the objects. * * This lock must be different than the initLock because the initLock is * held during creation of synchronization objects. * * Results: * None. * * Side effects: * Acquire the global mutex. * *---------------------------------------------------------------------- */ void TclpGlobalLock(void) { #if TCL_THREADS pthread_mutex_lock(&globalLock); #endif } /* *---------------------------------------------------------------------- * * TclpGlobalUnlock * * This procedure is used to release a lock that serializes creation and * finalization of synchronization objects. * * Results: * None. * * Side effects: * Release the global mutex. * *---------------------------------------------------------------------- */ void TclpGlobalUnlock(void) { #if TCL_THREADS pthread_mutex_unlock(&globalLock); #endif } /* *---------------------------------------------------------------------- * * Tcl_GetAllocMutex * * This procedure returns a pointer to a statically initialized mutex for * use by the memory allocator. The allocator must use this lock, because * all other locks are allocated... * * Results: * A pointer to a mutex that is suitable for passing to Tcl_MutexLock and * Tcl_MutexUnlock. * * Side effects: * None. * *---------------------------------------------------------------------- */ Tcl_Mutex * Tcl_GetAllocMutex(void) { #if TCL_THREADS PMutex **allocLockPtrPtr = &allocLockPtr; pthread_once(&allocLockInitOnce, allocLockInit); return (Tcl_Mutex *) allocLockPtrPtr; #else return NULL; #endif } #if TCL_THREADS /* *---------------------------------------------------------------------- * * Tcl_MutexLock -- * * This procedure is invoked to lock a mutex. This procedure handles * initializing the mutex, if necessary. The caller can rely on the fact * that Tcl_Mutex is an opaque pointer. This routine will change that * pointer from NULL after first use. * * Results: * None. * * Side effects: * May block the current thread. The mutex is acquired when this returns. * Will allocate memory for a pthread_mutex_t and initialize this the * first time this Tcl_Mutex is used. * *---------------------------------------------------------------------- */ void Tcl_MutexLock( Tcl_Mutex *mutexPtr) /* Really (PMutex **) */ { PMutex *pmutexPtr; if (*mutexPtr == NULL) { pthread_mutex_lock(&globalLock); if (*mutexPtr == NULL) { /* * Double inside global lock check to avoid a race condition. */ pmutexPtr = (PMutex *)ckalloc(sizeof(PMutex)); PMutexInit(pmutexPtr); *mutexPtr = (Tcl_Mutex) pmutexPtr; TclRememberMutex(mutexPtr); } pthread_mutex_unlock(&globalLock); } pmutexPtr = *((PMutex **) mutexPtr); PMutexLock(pmutexPtr); } /* *---------------------------------------------------------------------- * * Tcl_MutexUnlock -- * * This procedure is invoked to unlock a mutex. The mutex must have been * locked by Tcl_MutexLock. * * Results: * None. * * Side effects: * The mutex is released when this returns. * *---------------------------------------------------------------------- */ void Tcl_MutexUnlock( Tcl_Mutex *mutexPtr) /* Really (PMutex **) */ { PMutex *pmutexPtr = *(PMutex **) mutexPtr; PMutexUnlock(pmutexPtr); } /* *---------------------------------------------------------------------- * * TclpFinalizeMutex -- * * This procedure is invoked to clean up one mutex. This is only safe to * call at the end of time. * * This assumes the Global Lock is held. * * Results: * None. * * Side effects: * The mutex list is deallocated. * *---------------------------------------------------------------------- */ void TclpFinalizeMutex( Tcl_Mutex *mutexPtr) { PMutex *pmutexPtr = *(PMutex **) mutexPtr; if (pmutexPtr != NULL) { PMutexDestroy(pmutexPtr); ckfree(pmutexPtr); *mutexPtr = NULL; } } /* *---------------------------------------------------------------------- * * Tcl_ConditionWait -- * * This procedure is invoked to wait on a condition variable. The mutex * is automically released as part of the wait, and automatically grabbed * when the condition is signaled. * * The mutex must be held when this procedure is called. * * Results: * None. * * Side effects: * May block the current thread. The mutex is acquired when this returns. * Will allocate memory for a pthread_mutex_t and initialize this the * first time this Tcl_Mutex is used. * *---------------------------------------------------------------------- */ void Tcl_ConditionWait( Tcl_Condition *condPtr, /* Really (pthread_cond_t **) */ Tcl_Mutex *mutexPtr, /* Really (PMutex **) */ const Tcl_Time *timePtr) /* Timeout on waiting period */ { pthread_cond_t *pcondPtr; PMutex *pmutexPtr; struct timespec ptime; if (*condPtr == NULL) { pthread_mutex_lock(&globalLock); /* * Double check inside mutex to avoid race, then initialize condition * variable if necessary. */ if (*condPtr == NULL) { pcondPtr = (pthread_cond_t *)ckalloc(sizeof(pthread_cond_t)); pthread_cond_init(pcondPtr, NULL); *condPtr = (Tcl_Condition) pcondPtr; TclRememberCondition(condPtr); } pthread_mutex_unlock(&globalLock); } pmutexPtr = *((PMutex **)mutexPtr); pcondPtr = *((pthread_cond_t **)condPtr); if (timePtr == NULL) { PCondWait(pcondPtr, pmutexPtr); } else { Tcl_Time now; /* * Make sure to take into account the microsecond component of the * current time, including possible overflow situations. [Bug #411603] */ Tcl_GetTime(&now); ptime.tv_sec = timePtr->sec + now.sec + (timePtr->usec + now.usec) / 1000000; ptime.tv_nsec = 1000 * ((timePtr->usec + now.usec) % 1000000); PCondTimedWait(pcondPtr, pmutexPtr, &ptime); } } /* *---------------------------------------------------------------------- * * Tcl_ConditionNotify -- * * This procedure is invoked to signal a condition variable. * * The mutex must be held during this call to avoid races, but this * interface does not enforce that. * * Results: * None. * * Side effects: * May unblock another thread. * *---------------------------------------------------------------------- */ void Tcl_ConditionNotify( Tcl_Condition *condPtr) { pthread_cond_t *pcondPtr = *((pthread_cond_t **)condPtr); if (pcondPtr != NULL) { pthread_cond_broadcast(pcondPtr); } else { /* * No-one has used the condition variable, so there are no waiters. */ } } /* *---------------------------------------------------------------------- * * TclpFinalizeCondition -- * * This procedure is invoked to clean up a condition variable. This is * only safe to call at the end of time. * * This assumes the Global Lock is held. * * Results: * None. * * Side effects: * The condition variable is deallocated. * *---------------------------------------------------------------------- */ void TclpFinalizeCondition( Tcl_Condition *condPtr) { pthread_cond_t *pcondPtr = *(pthread_cond_t **)condPtr; if (pcondPtr != NULL) { pthread_cond_destroy(pcondPtr); ckfree(pcondPtr); *condPtr = NULL; } } #endif /* TCL_THREADS */ /* *---------------------------------------------------------------------- * * TclpReaddir, TclpInetNtoa -- * * These procedures replace core C versions to be used in a threaded * environment. * * Results: * See documentation of C functions. * * Side effects: * See documentation of C functions. * * Notes: * TclpReaddir is no longer used by the core (see 1095909), but it * appears in the internal stubs table (see #589526). * *---------------------------------------------------------------------- */ #ifndef TCL_NO_DEPRECATED Tcl_DirEntry * TclpReaddir( TclDIR * dir) { return TclOSreaddir(dir); } #undef TclpInetNtoa char * TclpInetNtoa( struct in_addr addr) { #if TCL_THREADS ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); unsigned char *b = (unsigned char*) &addr.s_addr; snprintf(tsdPtr->nabuf, sizeof(tsdPtr->nabuf), "%u.%u.%u.%u", b[0], b[1], b[2], b[3]); return tsdPtr->nabuf; #else return inet_ntoa(addr); #endif } #endif /* TCL_NO_DEPRECATED */ #if TCL_THREADS /* * Additions by AOL for specialized thread memory allocator. */ #ifdef USE_THREAD_ALLOC static pthread_key_t key; typedef struct { Tcl_Mutex tlock; PMutex plock; } AllocMutex; Tcl_Mutex * TclpNewAllocMutex(void) { AllocMutex *lockPtr; PMutex *plockPtr; lockPtr = (AllocMutex *)malloc(sizeof(AllocMutex)); if (lockPtr == NULL) { Tcl_Panic("could not allocate lock"); } plockPtr = &lockPtr->plock; lockPtr->tlock = (Tcl_Mutex) plockPtr; PMutexInit(&lockPtr->plock); return &lockPtr->tlock; } void TclpFreeAllocMutex( Tcl_Mutex *mutex) /* The alloc mutex to free. */ { AllocMutex *lockPtr = (AllocMutex *)mutex; if (!lockPtr) { return; } PMutexDestroy(&lockPtr->plock); free(lockPtr); } void TclpInitAllocCache(void) { pthread_key_create(&key, NULL); } void TclpFreeAllocCache( void *ptr) { if (ptr != NULL) { /* * Called by TclFinalizeThreadAllocThread() during the thread * finalization initiated from Tcl_FinalizeThread() */ TclFreeAllocCache(ptr); pthread_setspecific(key, NULL); } else { /* * Called by TclFinalizeThreadAlloc() during the process * finalization initiated from Tcl_Finalize() */ pthread_key_delete(key); } } void * TclpGetAllocCache(void) { return pthread_getspecific(key); } void TclpSetAllocCache( void *arg) { pthread_setspecific(key, arg); } #endif /* USE_THREAD_ALLOC */ void * TclpThreadCreateKey(void) { pthread_key_t *ptkeyPtr; ptkeyPtr = (pthread_key_t *)TclpSysAlloc(sizeof(pthread_key_t), 0); if (NULL == ptkeyPtr) { Tcl_Panic("unable to allocate thread key!"); } if (pthread_key_create(ptkeyPtr, NULL)) { Tcl_Panic("unable to create pthread key!"); } return ptkeyPtr; } void TclpThreadDeleteKey( void *keyPtr) { pthread_key_t *ptkeyPtr = (pthread_key_t *)keyPtr; if (pthread_key_delete(*ptkeyPtr)) { Tcl_Panic("unable to delete key!"); } TclpSysFree(keyPtr); } void TclpThreadSetGlobalTSD( void *tsdKeyPtr, void *ptr) { pthread_key_t *ptkeyPtr = (pthread_key_t *)tsdKeyPtr; if (pthread_setspecific(*ptkeyPtr, ptr)) { Tcl_Panic("unable to set global TSD value"); } } void * TclpThreadGetGlobalTSD( void *tsdKeyPtr) { pthread_key_t *ptkeyPtr = (pthread_key_t *)tsdKeyPtr; return pthread_getspecific(*ptkeyPtr); } #endif /* TCL_THREADS */ /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */