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Diffstat (limited to 'unix/tclUnixNotfy.c')
| -rw-r--r-- | unix/tclUnixNotfy.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c new file mode 100644 index 0000000..5bc753a --- /dev/null +++ b/unix/tclUnixNotfy.c @@ -0,0 +1,575 @@ +/* + * tclUnixNotfy.c -- + * + * This file contains subroutines shared by all notifier backend + * implementations on *nix platforms. + * + * Copyright (c) 1995-1997 Sun Microsystems, Inc. + * Copyright (c) 2016 Lucio AndrĂ©s Illanes Albornoz <l.illanes@gmx.de> + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + */ + +#include <poll.h> + +/* + * Static routines defined in this file. + */ + +#ifdef NOTIFIER_SELECT +#ifdef TCL_THREADS +static TCL_NORETURN void NotifierThreadProc(ClientData clientData); +#if defined(HAVE_PTHREAD_ATFORK) +static void AtForkChild(void); +#endif /* HAVE_PTHREAD_ATFORK */ +#endif /* TCL_THREADS */ +#endif /* NOTIFIER_SELECT */ +static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); + +#ifdef NOTIFIER_SELECT +#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(const char *proc) +{ + if (!notifierThreadRunning) { + pthread_mutex_lock(¬ifierInitMutex); + if (!notifierThreadRunning) { + if (TclpThreadCreate(¬ifierThread, NotifierThreadProc, NULL, + TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) { + Tcl_Panic("%s: unable to start notifier thread", proc); + } + + 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 */ +#endif /* NOTIFIER_SELECT */ + +/* + *---------------------------------------------------------------------- + * + * Tcl_AlertNotifier -- + * + * Wake up the specified notifier from any thread. This routine is called + * by the platform independent notifier code whenever the Tcl_ThreadAlert + * routine is called. This routine is guaranteed not to be called on a + * given notifier after Tcl_FinalizeNotifier is called for that notifier. + * + * Results: + * None. + * + * Side effects: + * select(2) notifier: + * signals the notifier condition variable for the specified + * notifier. + * epoll(7) notifier: + * write(2)s to the eventfd(2) of the specified thread. + * kqueue(2) notifier: + * write(2)s to the trigger pipe(2) of the specified thread. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_AlertNotifier( + ClientData clientData) +{ + if (tclNotifierHooks.alertNotifierProc) { + tclNotifierHooks.alertNotifierProc(clientData); + return; + } else { +#ifdef NOTIFIER_SELECT +#ifdef TCL_THREADS + ThreadSpecificData *tsdPtr = clientData; + + pthread_mutex_lock(¬ifierMutex); + tsdPtr->eventReady = 1; + +# ifdef __CYGWIN__ + PostMessageW(tsdPtr->hwnd, 1024, 0, 0); +# else + pthread_cond_broadcast(&tsdPtr->waitCV); +# endif /* __CYGWIN__ */ + pthread_mutex_unlock(¬ifierMutex); +#endif /* TCL_THREADS */ +#else + ThreadSpecificData *tsdPtr = clientData; +#if defined(NOTIFIER_EPOLL) && defined(HAVE_EVENTFD) + uint64_t eventFdVal = 1; + if (write(tsdPtr->triggerEventFd, &eventFdVal, + sizeof(eventFdVal)) != sizeof(eventFdVal)) { + Tcl_Panic("Tcl_AlertNotifier: unable to write to %p->triggerEventFd", + (void *)tsdPtr); +#else + if (write(tsdPtr->triggerPipe[1], "", 1) != 1) { + Tcl_Panic("Tcl_AlertNotifier: unable to write to %p->triggerPipe", + (void *)tsdPtr); +#endif /* NOTIFIER_EPOLL && HAVE_EVENTFD */ + } +#endif /* NOTIFIER_SELECT */ + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetTimer -- + * + * This function sets the current notifier timer value. This interface is + * not implemented in this notifier because we are always running inside + * of Tcl_DoOneEvent. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_SetTimer( + const Tcl_Time *timePtr) /* Timeout value, may be NULL. */ +{ + if (tclNotifierHooks.setTimerProc) { + tclNotifierHooks.setTimerProc(timePtr); + return; + } else { + /* + * The interval timer doesn't do anything in this implementation, + * because the only event loop is via Tcl_DoOneEvent, which passes + * timeout values to Tcl_WaitForEvent. + */ + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_ServiceModeHook -- + * + * This function is invoked whenever the service mode changes. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_ServiceModeHook( + int mode) /* Either TCL_SERVICE_ALL, or + * TCL_SERVICE_NONE. */ +{ + if (tclNotifierHooks.serviceModeHookProc) { + tclNotifierHooks.serviceModeHookProc(mode); + return; + } else if (mode == TCL_SERVICE_ALL) { +#ifdef NOTIFIER_SELECT +#if TCL_THREADS + StartNotifierThread("Tcl_ServiceModeHook"); +#endif +#endif /* NOTIFIER_SELECT */ + } +} + +/* + *---------------------------------------------------------------------- + * + * FileHandlerEventProc -- + * + * This function is called by Tcl_ServiceEvent when a file event reaches + * the front of the event queue. This function is responsible for + * actually handling the event by invoking the callback for the file + * handler. + * + * Results: + * Returns 1 if the event was handled, meaning it should be removed from + * the queue. Returns 0 if the event was not handled, meaning it should + * stay on the queue. The only time the event isn't handled is if the + * TCL_FILE_EVENTS flag bit isn't set. + * + * Side effects: + * Whatever the file handler's callback function does. + * + *---------------------------------------------------------------------- + */ + +static int +FileHandlerEventProc( + Tcl_Event *evPtr, /* Event to service. */ + int flags) /* Flags that indicate what events to handle, + * such as TCL_FILE_EVENTS. */ +{ + int mask; + FileHandler *filePtr; + FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr; + ThreadSpecificData *tsdPtr; + + if (!(flags & TCL_FILE_EVENTS)) { + return 0; + } + + /* + * Search through the file handlers to find the one whose handle matches + * the event. We do this rather than keeping a pointer to the file handler + * directly in the event, so that the handler can be deleted while the + * event is queued without leaving a dangling pointer. + */ + + tsdPtr = TCL_TSD_INIT(&dataKey); + + for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; + filePtr = filePtr->nextPtr) { + if (filePtr->fd != fileEvPtr->fd) { + continue; + } + + /* + * The code is tricky for two reasons: + * 1. The file handler's desired events could have changed since the + * time when the event was queued, so AND the ready mask with the + * desired mask. + * 2. The file could have been closed and re-opened since the time + * when the event was queued. This is why the ready mask is stored + * in the file handler rather than the queued event: it will be + * zeroed when a new file handler is created for the newly opened + * file. + */ + + mask = filePtr->readyMask & filePtr->mask; + filePtr->readyMask = 0; + if (mask != 0) { + filePtr->proc(filePtr->clientData, mask); + } + break; + } + return 1; +} + +#ifdef NOTIFIER_SELECT +#ifdef TCL_THREADS +/* + *---------------------------------------------------------------------- + * + * AlertSingleThread -- + * + * Notify a single thread that is waiting on a file descriptor to become + * readable or writable or to have an exception condition. + * notifierMutex must be held. + * + * Result: + * None. + * + * Side effects: + * The condition variable associated with the thread is broadcasted. + * + *---------------------------------------------------------------------- + */ + +static void +AlertSingleThread( + ThreadSpecificData *tsdPtr) +{ + tsdPtr->eventReady = 1; + if (tsdPtr->onList) { + /* + * Remove the ThreadSpecificData structure of this thread + * from the waiting list. This prevents us from + * continuously spinning on epoll_wait until the other + * threads runs and services the file event. + */ + + if (tsdPtr->prevPtr) { + tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr; + } else { + waitingListPtr = tsdPtr->nextPtr; + } + if (tsdPtr->nextPtr) { + tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr; + } + tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; + tsdPtr->onList = 0; + tsdPtr->pollState = 0; + } +#ifdef __CYGWIN__ + PostMessageW(tsdPtr->hwnd, 1024, 0, 0); +#else /* __CYGWIN__ */ + pthread_cond_broadcast(&tsdPtr->waitCV); +#endif /* __CYGWIN__ */ +} + +#if defined(HAVE_PTHREAD_ATFORK) +/* + *---------------------------------------------------------------------- + * + * AtForkChild -- + * + * Unlock and reinstall the notifier in the child after a fork. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +AtForkChild(void) +{ + if (notifierThreadRunning == 1) { + pthread_cond_destroy(¬ifierCV); + } + pthread_mutex_init(¬ifierInitMutex, NULL); + pthread_mutex_init(¬ifierMutex, NULL); + 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) { + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + 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. + */ +#ifdef __CYGWIN__ + DestroyWindow(tsdPtr->hwnd); + tsdPtr->hwnd = CreateWindowExW(NULL, className, + className, 0, 0, 0, 0, 0, NULL, NULL, + TclWinGetTclInstance(), NULL); + ResetEvent(tsdPtr->event); +#else + pthread_cond_destroy(&tsdPtr->waitCV); + pthread_cond_init(&tsdPtr->waitCV, NULL); +#endif + + /* + * In case, we had multiple threads running before the fork, + * make sure, we don't try to reach out to their thread local data. + */ + tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; + + /* + * The list of registered event handlers at fork time is in + * tsdPtr->firstFileHandlerPtr; + */ + } + } + + Tcl_InitNotifier(); +} +#endif /* HAVE_PTHREAD_ATFORK */ + +#endif /* TCL_THREADS */ + +#endif /* NOTIFIER_SELECT */ +#ifndef HAVE_COREFOUNDATION /* Darwin/Mac OS X CoreFoundation notifier is + * in tclMacOSXNotify.c */ +/* + *---------------------------------------------------------------------- + * + * TclUnixWaitForFile -- + * + * This function waits synchronously for a file to become readable or + * writable, with an optional timeout. + * + * Results: + * The return value is an OR'ed combination of TCL_READABLE, + * TCL_WRITABLE, and TCL_EXCEPTION, indicating the conditions that are + * present on file at the time of the return. This function will not + * return until either "timeout" milliseconds have elapsed or at least + * one of the conditions given by mask has occurred for file (a return + * value of 0 means that a timeout occurred). No normal events will be + * serviced during the execution of this function. + * + * Side effects: + * Time passes. + * + *---------------------------------------------------------------------- + */ + +int +TclUnixWaitForFile( + int fd, /* Handle for file on which to wait. */ + int mask, /* What to wait for: OR'ed combination of + * TCL_READABLE, TCL_WRITABLE, and + * TCL_EXCEPTION. */ + int timeout) /* Maximum amount of time to wait for one of + * the conditions in mask to occur, in + * milliseconds. A value of 0 means don't wait + * at all, and a value of -1 means wait + * forever. */ +{ + Tcl_Time abortTime = {0, 0}, now; /* silence gcc 4 warning */ + struct timeval blockTime, *timeoutPtr; + struct pollfd pollFds[1]; + int numFound, result = 0, pollTimeout; + + /* + * If there is a non-zero finite timeout, compute the time when we give + * up. + */ + + if (timeout > 0) { + Tcl_GetTime(&now); + abortTime.sec = now.sec + timeout/1000; + abortTime.usec = now.usec + (timeout%1000)*1000; + if (abortTime.usec >= 1000000) { + abortTime.usec -= 1000000; + abortTime.sec += 1; + } + timeoutPtr = &blockTime; + } else if (timeout == 0) { + timeoutPtr = &blockTime; + blockTime.tv_sec = 0; + blockTime.tv_usec = 0; + } else { + timeoutPtr = NULL; + } + + /* + * Setup the pollfd structure for the fd. + */ + + pollFds[0].fd = fd; + pollFds[0].events = pollFds[0].revents = 0; + if (mask & TCL_READABLE) { + pollFds[0].events |= (POLLIN | POLLHUP); + } + if (mask & TCL_WRITABLE) { + pollFds[0].events |= POLLOUT; + } + if (mask & TCL_EXCEPTION) { + pollFds[0].events |= POLLERR; + } + + /* + * Loop in a mini-event loop of our own, waiting for either the file to + * become ready or a timeout to occur. + */ + + while (1) { + if (timeout > 0) { + blockTime.tv_sec = abortTime.sec - now.sec; + blockTime.tv_usec = abortTime.usec - now.usec; + if (blockTime.tv_usec < 0) { + blockTime.tv_sec -= 1; + blockTime.tv_usec += 1000000; + } + if (blockTime.tv_sec < 0) { + blockTime.tv_sec = 0; + blockTime.tv_usec = 0; + } + } + + /* + * Wait for the event or a timeout. + */ + + if (!timeoutPtr) { + pollTimeout = -1; + } else if (!timeoutPtr->tv_sec && !timeoutPtr->tv_usec) { + pollTimeout = 0; + } else { + pollTimeout = (int)timeoutPtr->tv_sec * 1000; + if (timeoutPtr->tv_usec) { + pollTimeout += ((int)timeoutPtr->tv_usec / 1000); + } + } + numFound = poll(pollFds, 1, pollTimeout); + if (numFound == 1) { + result = 0; + if (pollFds[0].events & (POLLIN | POLLHUP)) { + result |= TCL_READABLE; + } + if (pollFds[0].events & POLLOUT) { + result |= TCL_WRITABLE; + } + if (pollFds[0].events & POLLERR) { + result |= TCL_EXCEPTION; + } + if (result) { + break; + } + } + if (timeout == 0) { + break; + } + if (timeout < 0) { + continue; + } + + /* + * The select returned early, so we need to recompute the timeout. + */ + + Tcl_GetTime(&now); + if ((abortTime.sec < now.sec) + || (abortTime.sec==now.sec && abortTime.usec<=now.usec)) { + break; + } + } + return result; +} +#endif /* !HAVE_COREFOUNDATION */ + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |