tclUnixThrd.c Go to the documentation of this file. /* * tclUnixThrd.c -- * * This file implements the UNIX-specific thread support. * * Copyright (c) 1991-1994 The Regents of the University of California. * Copyright (c) 1994-1997 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * * RCS: @(#) $Id: tclUnixThrd.c,v 1.57 2008/01/11 11:53:02 msofer Exp $ */ #include "tclInt.h" #ifdef TCL_THREADS #include "pthread.h" typedef struct ThreadSpecificData { char nabuf[16]; } ThreadSpecificData; static Tcl_ThreadDataKey dataKey; /* * masterLock 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 masterLock = PTHREAD_MUTEX_INITIALIZER; /* * initLock is used to serialize initialization and finalization of Tcl. It * cannot use any dyamically 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 dyamically allocated storage. */ static pthread_mutex_t allocLock = PTHREAD_MUTEX_INITIALIZER; static pthread_mutex_t *allocLockPtr = &allocLock; /* * These are for the critical sections inside this file. */ #define MASTER_LOCK pthread_mutex_lock(&masterLock) #define MASTER_UNLOCK pthread_mutex_unlock(&masterLock) #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 */ ClientData clientData, /* The one argument to Main() */ int stackSize, /* Size of stack for the new thread */ int flags) /* Flags controlling behaviour of the new * thread. */ { #ifdef 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 } #endif if (! (flags & TCL_THREAD_JOINABLE)) { pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); } if (pthread_create(&theThread, &attr, (void * (*)(void *))proc, (void *)clientData) && pthread_create(&theThread, NULL, (void * (*)(void *))proc, (void *)clientData)) { result = TCL_ERROR; } else { *idPtr = (Tcl_ThreadId)theThread; result = TCL_OK; } pthread_attr_destroy(&attr); return result; #else 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. */ { #ifdef 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 return TCL_ERROR; #endif }  #ifdef TCL_THREADS /* *---------------------------------------------------------------------- * * TclpThreadExit -- * * This procedure terminates the current thread. * * Results: * None. * * Side effects: * This procedure terminates the current thread. * *---------------------------------------------------------------------- */ void TclpThreadExit( int status) { pthread_exit(INT2PTR(status)); } #endif /* TCL_THREADS */  #ifdef TCL_THREADS /* *---------------------------------------------------------------------- * * TclpThreadGetStackSize -- * * This procedure returns the size of the current thread's stack. * * Results: * Stack size (in bytes?) or -1 for error or 0 for undeterminable. * * Side effects: * None. * *---------------------------------------------------------------------- */ size_t TclpThreadGetStackSize(void) { size_t stackSize = 0; #if defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE) && defined(TclpPthreadGetAttrs) pthread_attr_t threadAttr; /* This will hold the thread attributes for * the current thread. */ #ifdef __GLIBC__ /* * Fix for [Bug 1815573] * * DESCRIPTION: * On linux TclpPthreadGetAttrs (which is pthread_attr_get_np) may return * bogus values on the initial thread. * * ASSUMPTIONS: * There seems to be no api to determine if we are on the initial * thread. The simple scheme implemented here assumes: * 1. The first Tcl interp to be created lives in the initial thread. If * this assumption is not true, the fix is to call * TclpThreadGetStackSize from the initial thread previous to * creating any Tcl interpreter. In this case, especially if another * Tcl interpreter may be created in the initial thread, it might be * better to enable the second branch in the #if below * 2. There will be no races in creating the first Tcl interp - ie, the * second Tcl interp will be created only after the first call to * Tcl_CreateInterp returns. * * These assumptions are satisfied by tclsh. Embedders on linux may want * to check their validity, and possibly adapt the code on failing to meet * them. */ static int initialized = 0; if (!initialized) { initialized = 1; return 0; } else { #else { #endif if (pthread_attr_init(&threadAttr) != 0) { return -1; } if (TclpPthreadGetAttrs(pthread_self(), &threadAttr) != 0) { pthread_attr_destroy(&threadAttr); return (size_t)-1; } } if (pthread_attr_getstacksize(&threadAttr, &stackSize) != 0) { pthread_attr_destroy(&threadAttr); return (size_t)-1; } pthread_attr_destroy(&threadAttr); #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) #ifdef __APPLE__ /* * On Darwin, the API below does not return the correct stack size for the * main thread (which is not a real pthread), so fallback to getrlimit(). */ if (!pthread_main_np()) #endif stackSize = pthread_get_stacksize_np(pthread_self()); #else /* * Cannot determine the real stack size of this thread. The caller might * want to try looking at the process accounting limits instead. */ #endif return stackSize; } #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) { #ifdef 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) { #ifdef TCL_THREADS pthread_mutex_lock(&initLock); #endif }  /* *---------------------------------------------------------------------- * * TclpFinalizeLock * * 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) { #ifdef 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: masterLock, 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) { #ifdef TCL_THREADS pthread_mutex_unlock(&initLock); #endif }  /* *---------------------------------------------------------------------- * * TclpMasterLock * * 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 syncronization objects. * * Results: * None. * * Side effects: * Acquire the master mutex. * *---------------------------------------------------------------------- */ void TclpMasterLock(void) { #ifdef TCL_THREADS pthread_mutex_lock(&masterLock); #endif }  /* *---------------------------------------------------------------------- * * TclpMasterUnlock * * This procedure is used to release a lock that serializes creation and * finalization of synchronization objects. * * Results: * None. * * Side effects: * Release the master mutex. * *---------------------------------------------------------------------- */ void TclpMasterUnlock(void) { #ifdef TCL_THREADS pthread_mutex_unlock(&masterLock); #endif }  /* *---------------------------------------------------------------------- * * Tcl_GetAllocMutex * * This procedure returns a pointer to a statically initialized mutex for * use by the memory allocator. The alloctor 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) { #ifdef TCL_THREADS pthread_mutex_t **allocLockPtrPtr = &allocLockPtr; return (Tcl_Mutex *) allocLockPtrPtr; #else return NULL; #endif } #ifdef 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 aquired 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 (pthread_mutex_t **) */ { pthread_mutex_t *pmutexPtr; if (*mutexPtr == NULL) { MASTER_LOCK; if (*mutexPtr == NULL) { /* * Double inside master lock check to avoid a race condition. */ pmutexPtr = (pthread_mutex_t *)ckalloc(sizeof(pthread_mutex_t)); pthread_mutex_init(pmutexPtr, NULL); *mutexPtr = (Tcl_Mutex)pmutexPtr; TclRememberMutex(mutexPtr); } MASTER_UNLOCK; } pmutexPtr = *((pthread_mutex_t **)mutexPtr); pthread_mutex_lock(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 (pthread_mutex_t **) */ { pthread_mutex_t *pmutexPtr = *(pthread_mutex_t **)mutexPtr; pthread_mutex_unlock(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 Master Lock is held. * * Results: * None. * * Side effects: * The mutex list is deallocated. * *---------------------------------------------------------------------- */ void TclpFinalizeMutex( Tcl_Mutex *mutexPtr) { pthread_mutex_t *pmutexPtr = *(pthread_mutex_t **)mutexPtr; if (pmutexPtr != NULL) { pthread_mutex_destroy(pmutexPtr); ckfree((char *) 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 aquired 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 (pthread_mutex_t **) */ Tcl_Time *timePtr) /* Timeout on waiting period */ { pthread_cond_t *pcondPtr; pthread_mutex_t *pmutexPtr; struct timespec ptime; if (*condPtr == NULL) { MASTER_LOCK; /* * 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); } MASTER_UNLOCK; } pmutexPtr = *((pthread_mutex_t **)mutexPtr); pcondPtr = *((pthread_cond_t **)condPtr); if (timePtr == NULL) { pthread_cond_wait(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); pthread_cond_timedwait(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 { /* * Noone 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 Master 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((char *) pcondPtr); *condPtr = NULL; } } #endif /* TCL_THREADS */  /* *---------------------------------------------------------------------- * * TclpReaddir, TclpLocaltime, TclpGmtime, 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). * *---------------------------------------------------------------------- */ Tcl_DirEntry * TclpReaddir( DIR * dir) { return TclOSreaddir(dir); } char * TclpInetNtoa( struct in_addr addr) { #ifdef TCL_THREADS ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); unsigned char *b = (unsigned char*) &addr.s_addr; sprintf(tsdPtr->nabuf, "%u.%u.%u.%u", b[0], b[1], b[2], b[3]); return tsdPtr->nabuf; #else return inet_ntoa(addr); #endif }  #ifdef TCL_THREADS /* * Additions by AOL for specialized thread memory allocator. */ #ifdef USE_THREAD_ALLOC static volatile int initialized = 0; static pthread_key_t key; typedef struct allocMutex { Tcl_Mutex tlock; pthread_mutex_t plock; } allocMutex; Tcl_Mutex * TclpNewAllocMutex(void) { struct allocMutex *lockPtr; register pthread_mutex_t *plockPtr; lockPtr = malloc(sizeof(struct allocMutex)); if (lockPtr == NULL) { Tcl_Panic("could not allocate lock"); } plockPtr = &lockPtr->plock; lockPtr->tlock = (Tcl_Mutex) plockPtr; pthread_mutex_init(&lockPtr->plock, NULL); return &lockPtr->tlock; } void TclpFreeAllocMutex( Tcl_Mutex *mutex) /* The alloc mutex to free. */ { allocMutex* lockPtr = (allocMutex*) mutex; if (!lockPtr) { return; } pthread_mutex_destroy(&lockPtr->plock); free(lockPtr); } void TclpFreeAllocCache( void *ptr) { if (ptr != NULL) { /* * Called by the pthread lib when a thread exits */ TclFreeAllocCache(ptr); } else if (initialized) { /* * Called by us in TclFinalizeThreadAlloc() during the library * finalization initiated from Tcl_Finalize() */ pthread_key_delete(key); initialized = 0; } } void * TclpGetAllocCache(void) { if (!initialized) { pthread_mutex_lock(allocLockPtr); if (!initialized) { pthread_key_create(&key, TclpFreeAllocCache); initialized = 1; } pthread_mutex_unlock(allocLockPtr); } return pthread_getspecific(key); } void TclpSetAllocCache( void *arg) { pthread_setspecific(key, arg); } #endif /* USE_THREAD_ALLOC */ #endif /* TCL_THREADS */  /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */

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