diff options
Diffstat (limited to 'unix/tclUnixNotfy.c')
| -rw-r--r-- | unix/tclUnixNotfy.c | 323 |
1 files changed, 216 insertions, 107 deletions
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c index 17fdc95..398e13a 100644 --- a/unix/tclUnixNotfy.c +++ b/unix/tclUnixNotfy.c @@ -1,3 +1,5 @@ +#define AT_FORK_INIT_VALUE 0 +#define RESET_ATFORK_MUTEX 1 /* * tclUnixNotify.c -- * @@ -15,6 +17,7 @@ #ifndef HAVE_COREFOUNDATION /* Darwin/Mac OS X CoreFoundation notifier is * in tclMacOSXNotify.c */ #include <signal.h> +#include <assert.h> /* * This structure is used to keep track of the notifier info for a registered @@ -97,9 +100,10 @@ typedef struct ThreadSpecificData { * by sending this event. */ void *hwnd; /* Messaging window. */ #else /* !__CYGWIN__ */ - Tcl_Condition waitCV; /* Any other thread alerts a notifier that an + pthread_cond_t waitCV; /* Any other thread alerts a notifier that an * event is ready to be processed by signaling * this condition variable. */ + int waitCVinitialized; /* Variable to flag initialization of the structure */ #endif /* __CYGWIN__ */ int eventReady; /* True if an event is ready to be processed. * Used as condition flag together with waitCV @@ -120,15 +124,6 @@ static Tcl_ThreadDataKey dataKey; static int notifierCount = 0; /* - * The following static stores the process ID of the initialized notifier - * thread. If it changes, we have passed a fork and we should start a new - * notifier thread. - * - * You must hold the notifierMutex lock before accessing this variable. - */ -static pid_t processIDInitialized = 0; - -/* * The following variable points to the head of a doubly-linked list of * ThreadSpecificData structures for all threads that are currently waiting on * an event. @@ -158,7 +153,15 @@ static int triggerPipe = -1; * The notifierMutex locks access to all of the global notifier state. */ -TCL_DECLARE_MUTEX(notifierMutex) +pthread_mutex_t notifierInitMutex = PTHREAD_MUTEX_INITIALIZER; +pthread_mutex_t notifierMutex = PTHREAD_MUTEX_INITIALIZER; +/* + * The following static indicates if the notifier thread is running. + * + * You must hold the notifierInitMutex before accessing this variable. + */ + +static int notifierThreadRunning = 0; /* * The notifier thread signals the notifierCV when it has finished @@ -166,7 +169,7 @@ TCL_DECLARE_MUTEX(notifierMutex) * terminates. */ -static Tcl_Condition notifierCV; +static pthread_cond_t notifierCV = PTHREAD_COND_INITIALIZER; /* * The pollState bits @@ -195,7 +198,7 @@ static Tcl_ThreadId notifierThread; #ifdef TCL_THREADS static void NotifierThreadProc(ClientData clientData); #if defined(HAVE_PTHREAD_ATFORK) && !defined(__APPLE__) && !defined(__hpux) -static int atForkInit = 0; +static int atForkInit = AT_FORK_INIT_VALUE; static void AtForkPrepare(void); static void AtForkParent(void); static void AtForkChild(void); @@ -258,6 +261,50 @@ static DWORD __stdcall NotifierProc(void *hwnd, unsigned int message, void *wParam, void *lParam); #endif /* TCL_THREADS && __CYGWIN__ */ +#if TCL_THREADS +/* + *---------------------------------------------------------------------- + * + * StartNotifierThread -- + * + * Start a notfier thread and wait for the notifier pipe to be created. + * + * Results: + * None. + * + * Side effects: + * Running Thread. + * + *---------------------------------------------------------------------- + */ +static void +StartNotifierThread(void) +{ + + pthread_mutex_lock(¬ifierInitMutex); + if (!notifierThreadRunning) { + fprintf(stderr, "=== StartNotifierThread()\n"); + if (TclpThreadCreate(¬ifierThread, NotifierThreadProc, NULL, + TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) { + Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread"); + } + + pthread_mutex_lock(¬ifierMutex); + /* + * Wait for the notifier pipe to be created. + */ + + while (triggerPipe < 0) { + pthread_cond_wait(¬ifierCV, ¬ifierMutex); + } + pthread_mutex_unlock(¬ifierMutex); + + notifierThreadRunning = 1; + } + pthread_mutex_unlock(¬ifierInitMutex); +} +#endif /* TCL_THREADS */ + /* *---------------------------------------------------------------------- * @@ -285,14 +332,20 @@ Tcl_InitNotifier(void) #ifdef TCL_THREADS tsdPtr->eventReady = 0; +#ifndef __CYGWIN__ /* - * Start the Notifier thread if necessary. + * Initialize thread specific condition variable for this thread. */ + if (tsdPtr->waitCVinitialized == 0) { + pthread_cond_init(&tsdPtr->waitCV, NULL); + tsdPtr->waitCVinitialized = 1; + } +#endif - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierInitMutex); #if defined(HAVE_PTHREAD_ATFORK) && !defined(__APPLE__) && !defined(__hpux) /* - * Install pthread_atfork handlers to reinitialize the notifier in the + * Install pthread_atfork handlers to clean up the notifier in the * child of a fork. */ @@ -305,36 +358,11 @@ Tcl_InitNotifier(void) atForkInit = 1; } #endif /* HAVE_PTHREAD_ATFORK */ - /* - * Check if my process id changed, e.g. I was forked - * In this case, restart the notifier thread and close the - * pipe to the original notifier thread - */ - if (notifierCount > 0 && processIDInitialized != getpid()) { - Tcl_ConditionFinalize(¬ifierCV); - notifierCount = 0; - processIDInitialized = 0; - close(triggerPipe); - triggerPipe = -1; - } - if (notifierCount == 0) { - if (TclpThreadCreate(¬ifierThread, NotifierThreadProc, NULL, - TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) { - Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread"); - } - processIDInitialized = getpid(); - } + notifierCount++; - /* - * Wait for the notifier pipe to be created. - */ + pthread_mutex_unlock(¬ifierInitMutex); - while (triggerPipe < 0) { - Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); - } - - Tcl_MutexUnlock(¬ifierMutex); #endif /* TCL_THREADS */ return tsdPtr; } @@ -369,46 +397,42 @@ Tcl_FinalizeNotifier( #ifdef TCL_THREADS ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierInitMutex); notifierCount--; /* + * Check if FinializeNotifier was called without a prior InitNotifier + * in this thread. + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); +#endif + + /* * If this is the last thread to use the notifier, close the notifier * pipe and wait for the background thread to terminate. */ if (notifierCount == 0) { - int result; - if (triggerPipe < 0) { - Tcl_Panic("Tcl_FinalizeNotifier: %s", - "notifier pipe not initialized"); - } - - /* - * Send "q" message to the notifier thread so that it will - * terminate. The notifier will return from its call to select() - * and notice that a "q" message has arrived, it will then close - * its side of the pipe and terminate its thread. Note the we can - * not just close the pipe and check for EOF in the notifier thread - * because if a background child process was created with exec, - * select() would not register the EOF on the pipe until the child - * processes had terminated. [Bug: 4139] [Bug: 1222872] - */ - - if (write(triggerPipe, "q", 1) != 1) { - Tcl_Panic("Tcl_FinalizeNotifier: %s", - "unable to write q to triggerPipe"); - } - close(triggerPipe); - while(triggerPipe >= 0) { - Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); - } + if (triggerPipe != -1) { + if (write(triggerPipe, "q", 1) != 1) { + Tcl_Panic("Tcl_FinalizeNotifier: %s", + "unable to write q to triggerPipe"); + } + close(triggerPipe); + while(triggerPipe != -1) { + pthread_cond_wait(¬ifierCV, ¬ifierMutex); + } + if (notifierThreadRunning) { + int result = pthread_join((pthread_t) notifierThread, NULL); - result = Tcl_JoinThread(notifierThread, NULL); - if (result) { - Tcl_Panic("Tcl_FinalizeNotifier: %s", - "unable to join notifier thread"); + if (result) { + Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier " + "thread"); + } + notifierThreadRunning = 0; + } } } @@ -419,10 +443,10 @@ Tcl_FinalizeNotifier( #ifdef __CYGWIN__ CloseHandle(tsdPtr->event); #else /* __CYGWIN__ */ - Tcl_ConditionFinalize(&(tsdPtr->waitCV)); + pthread_cond_destroy(&tsdPtr->waitCV); #endif /* __CYGWIN__ */ - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierInitMutex); #endif /* TCL_THREADS */ } } @@ -457,14 +481,15 @@ Tcl_AlertNotifier( #ifdef TCL_THREADS ThreadSpecificData *tsdPtr = clientData; - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); tsdPtr->eventReady = 1; + # ifdef __CYGWIN__ PostMessageW(tsdPtr->hwnd, 1024, 0, 0); # else - Tcl_ConditionNotify(&tsdPtr->waitCV); + pthread_cond_broadcast(&tsdPtr->waitCV); # endif /* __CYGWIN__ */ - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierMutex); #endif /* TCL_THREADS */ } } @@ -527,8 +552,10 @@ Tcl_ServiceModeHook( if (tclNotifierHooks.serviceModeHookProc) { tclNotifierHooks.serviceModeHookProc(mode); return; - } else { - /* Does nothing in this implementation. */ + } else if (mode == TCL_SERVICE_ALL) { +#if TCL_THREADS + StartNotifierThread(); +#endif } } @@ -566,6 +593,12 @@ Tcl_CreateFileHandler( ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); FileHandler *filePtr; + /* + * Check if InitNotifier was called before in this thread + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); +#endif for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; filePtr = filePtr->nextPtr) { if (filePtr->fd == fd) { @@ -638,6 +671,13 @@ Tcl_DeleteFileHandler( ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); /* + * Check if InitNotifier was called before in this thread + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); +#endif + + /* * Find the entry for the given file (and return if there isn't one). */ @@ -741,6 +781,14 @@ FileHandlerEventProc( */ tsdPtr = TCL_TSD_INIT(&dataKey); + + /* + * Check if InitNotifier was called before in this thread + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); +#endif + for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; filePtr = filePtr->nextPtr) { if (filePtr->fd != fileEvPtr->fd) { @@ -840,6 +888,13 @@ Tcl_WaitForEvent( ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); /* + * Check if InitNotifier was called before in this thread + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); +#endif + + /* * Set up the timeout structure. Note that if there are no events to * check for, we return with a negative result rather than blocking * forever. @@ -878,9 +933,11 @@ Tcl_WaitForEvent( #ifdef TCL_THREADS /* - * Place this thread on the list of interested threads, signal the - * notifier thread, and wait for a response or a timeout. + * Start notifier thread and place this thread on the list of + * interested threads, signal the notifier thread, and wait for a + * response or a timeout. */ + StartNotifierThread(); #ifdef __CYGWIN__ if (!tsdPtr->hwnd) { @@ -906,7 +963,7 @@ Tcl_WaitForEvent( } #endif /* __CYGWIN */ - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierInitMutex); if (timePtr != NULL && timePtr->sec == 0 && (timePtr->usec == 0 #if defined(__APPLE__) && defined(__LP64__) @@ -971,12 +1028,12 @@ Tcl_WaitForEvent( } else { timeout = 0xFFFFFFFF; } - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierMutex); MsgWaitForMultipleObjects(1, &tsdPtr->event, 0, timeout, 1279); - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); } #else - Tcl_ConditionWait(&tsdPtr->waitCV, ¬ifierMutex, timePtr); + pthread_cond_wait(&tsdPtr->waitCV, ¬ifierMutex); #endif /* __CYGWIN__ */ } tsdPtr->eventReady = 0; @@ -1079,7 +1136,7 @@ Tcl_WaitForEvent( filePtr->readyMask = mask; } #ifdef TCL_THREADS - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierInitMutex); #endif /* TCL_THREADS */ return 0; } @@ -1151,15 +1208,15 @@ NotifierThreadProc( * Install the write end of the pipe into the global variable. */ - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); triggerPipe = fds[1]; /* * Signal any threads that are waiting. */ - Tcl_ConditionNotify(¬ifierCV); - Tcl_MutexUnlock(¬ifierMutex); + pthread_cond_broadcast(¬ifierCV); + pthread_mutex_unlock(¬ifierMutex); /* * Look for file events and report them to interested threads. @@ -1175,7 +1232,7 @@ NotifierThreadProc( * notifiers. */ - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); timePtr = NULL; for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { for (i = tsdPtr->numFdBits-1; i >= 0; --i) { @@ -1202,7 +1259,7 @@ NotifierThreadProc( timePtr = &poll; } } - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierMutex); /* * Set up the select mask to include the receive pipe. @@ -1226,7 +1283,7 @@ NotifierThreadProc( * Alert any threads that are waiting on a ready file descriptor. */ - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { found = 0; @@ -1273,11 +1330,11 @@ NotifierThreadProc( #ifdef __CYGWIN__ PostMessageW(tsdPtr->hwnd, 1024, 0, 0); #else - Tcl_ConditionNotify(&tsdPtr->waitCV); + pthread_cond_broadcast(&tsdPtr->waitCV); #endif /* __CYGWIN__ */ } } - Tcl_MutexUnlock(¬ifierMutex); + pthread_mutex_unlock(¬ifierMutex); /* * Consume the next byte from the notifier pipe if the pipe was @@ -1306,10 +1363,10 @@ NotifierThreadProc( */ close(receivePipe); - Tcl_MutexLock(¬ifierMutex); + pthread_mutex_lock(¬ifierMutex); triggerPipe = -1; - Tcl_ConditionNotify(¬ifierCV); - Tcl_MutexUnlock(¬ifierMutex); + pthread_cond_broadcast(¬ifierCV); + pthread_mutex_unlock(¬ifierMutex); TclpThreadExit(0); } @@ -1334,9 +1391,9 @@ NotifierThreadProc( static void AtForkPrepare(void) { - Tcl_MutexLock(¬ifierMutex); - TclpMasterLock(); - TclpMutexLock(); +#if RESET_ATFORK_MUTEX == 0 + pthread_mutex_lock(¬ifierInitMutex); +#endif } /* @@ -1358,9 +1415,9 @@ AtForkPrepare(void) static void AtForkParent(void) { - TclpMutexUnlock(); - TclpMasterUnlock(); - Tcl_MutexUnlock(¬ifierMutex); +#if RESET_ATFORK_MUTEX == 0 + pthread_mutex_unlock(¬ifierInitMutex); +#endif } /* @@ -1382,9 +1439,61 @@ AtForkParent(void) static void AtForkChild(void) { - TclpMutexUnlock(); - TclpMasterUnlock(); - TclMutexUnlockAndFinalize(¬ifierMutex); + if (notifierThreadRunning == 1) { + pthread_cond_destroy(¬ifierCV); + } +#if RESET_ATFORK_MUTEX == 0 + pthread_mutex_unlock(¬ifierInitMutex); +#else + pthread_mutex_init(¬ifierInitMutex, NULL); + pthread_mutex_init(¬ifierMutex, NULL); +#endif + pthread_cond_init(¬ifierCV, NULL); + + /* + * notifierThreadRunning == 1: thread is running, (there might be data in notifier lists) + * atForkInit == 0: InitNotifier was never called + * notifierCount != 0: unbalanced InitNotifier() / FinalizeNotifier calls + * waitingListPtr != 0: there are threads currently waiting for events. + */ + + if (atForkInit == 1) { + + notifierCount = 0; + if (notifierThreadRunning == 1) { +#ifndef __CYGWIN__ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); +#endif + notifierThreadRunning = 0; + + close(triggerPipe); + triggerPipe = -1; + /* + * The waitingListPtr might contain event info from multiple + * threads, which are invalid here, so setting it to NULL is not + * unreasonable. + */ + waitingListPtr = NULL; + + /* + * The tsdPtr from before the fork is copied as well. But since + * we are paranoic, we don't trust its condvar and reset it. + */ +#ifndef __CYGWIN__ + assert(tsdPtr->waitCVinitialized == 1); + pthread_cond_destroy(&tsdPtr->waitCV); + pthread_cond_init(&tsdPtr->waitCV, NULL); +#endif + /* + * The list of registered event handlers at fork time is in + * tsdPtr->firstFileHandlerPtr; + */ + } + } + assert(notifierCount == 0); + assert(triggerPipe == -1); + assert(waitingListPtr == NULL); + Tcl_InitNotifier(); } #endif /* HAVE_PTHREAD_ATFORK */ |