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Diffstat (limited to 'unix/tclUnixNotfy.c')
| -rw-r--r-- | unix/tclUnixNotfy.c | 1033 |
1 files changed, 0 insertions, 1033 deletions
diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c deleted file mode 100644 index f376746..0000000 --- a/unix/tclUnixNotfy.c +++ /dev/null @@ -1,1033 +0,0 @@ -/* - * tclUnixNotify.c -- - * - * This file contains the implementation of the select-based - * Unix-specific notifier, which is the lowest-level part of the - * Tcl event loop. This file works together with - * ../generic/tclNotify.c. - * - * Copyright (c) 1995-1997 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: tclUnixNotfy.c,v 1.10 2000/04/24 23:32:13 hobbs Exp $ - */ - -#include "tclInt.h" -#include "tclPort.h" -#include <signal.h> - -extern TclStubs tclStubs; - -/* - * This structure is used to keep track of the notifier info for a - * a registered file. - */ - -typedef struct FileHandler { - int fd; - int mask; /* Mask of desired events: TCL_READABLE, - * etc. */ - int readyMask; /* Mask of events that have been seen since the - * last time file handlers were invoked for - * this file. */ - Tcl_FileProc *proc; /* Procedure to call, in the style of - * Tcl_CreateFileHandler. */ - ClientData clientData; /* Argument to pass to proc. */ - struct FileHandler *nextPtr;/* Next in list of all files we care about. */ -} FileHandler; - -/* - * The following structure is what is added to the Tcl event queue when - * file handlers are ready to fire. - */ - -typedef struct FileHandlerEvent { - Tcl_Event header; /* Information that is standard for - * all events. */ - int fd; /* File descriptor that is ready. Used - * to find the FileHandler structure for - * the file (can't point directly to the - * FileHandler structure because it could - * go away while the event is queued). */ -} FileHandlerEvent; - -/* - * The following static structure contains the state information for the - * select based implementation of the Tcl notifier. One of these structures - * is created for each thread that is using the notifier. - */ - -typedef struct ThreadSpecificData { - FileHandler *firstFileHandlerPtr; - /* Pointer to head of file handler list. */ - fd_mask checkMasks[3*MASK_SIZE]; - /* This array is used to build up the masks - * to be used in the next call to select. - * Bits are set in response to calls to - * Tcl_CreateFileHandler. */ - fd_mask readyMasks[3*MASK_SIZE]; - /* This array reflects the readable/writable - * conditions that were found to exist by the - * last call to select. */ - int numFdBits; /* Number of valid bits in checkMasks - * (one more than highest fd for which - * Tcl_WatchFile has been called). */ -#ifdef TCL_THREADS - int onList; /* True if it is in this list */ - unsigned int pollState; /* pollState is used to implement a polling - * handshake between each thread and the - * notifier thread. Bits defined below. */ - struct ThreadSpecificData *nextPtr, *prevPtr; - /* All threads that are currently waiting on - * an event have their ThreadSpecificData - * structure on a doubly-linked listed formed - * from these pointers. You must hold the - * notifierMutex lock before accessing these - * fields. */ - Tcl_Condition waitCV; /* Any other thread alerts a notifier - * that an event is ready to be processed - * by signaling this condition variable. */ - int eventReady; /* True if an event is ready to be processed. - * Used as condition flag together with - * waitCV above. */ -#endif -} ThreadSpecificData; - -static Tcl_ThreadDataKey dataKey; - -#ifdef TCL_THREADS -/* - * The following static indicates the number of threads that have - * initialized notifiers. - * - * You must hold the notifierMutex lock before accessing this variable. - */ - -static int notifierCount = 0; - -/* - * The following variable points to the head of a doubly-linked list of - * of ThreadSpecificData structures for all threads that are currently - * waiting on an event. - * - * You must hold the notifierMutex lock before accessing this list. - */ - -static ThreadSpecificData *waitingListPtr = NULL; - -/* - * The notifier thread spends all its time in select() waiting for a - * file descriptor associated with one of the threads on the waitingListPtr - * list to do something interesting. But if the contents of the - * waitingListPtr list ever changes, we need to wake up and restart - * the select() system call. You can wake up the notifier thread by - * writing a single byte to the file descriptor defined below. This - * file descriptor is the input-end of a pipe and the notifier thread is - * listening for data on the output-end of the same pipe. Hence writing - * to this file descriptor will cause the select() system call to return - * and wake up the notifier thread. - * - * You must hold the notifierMutex lock before accessing this list. - */ - -static int triggerPipe = -1; - -/* - * The notifierMutex locks access to all of the global notifier state. - */ - -TCL_DECLARE_MUTEX(notifierMutex) - -/* - * The notifier thread signals the notifierCV when it has finished - * initializing the triggerPipe and right before the notifier - * thread terminates. - */ - -static Tcl_Condition notifierCV; - -/* - * The pollState bits - * POLL_WANT is set by each thread before it waits on its condition - * variable. It is checked by the notifier before it does - * select. - * POLL_DONE is set by the notifier if it goes into select after - * seeing POLL_WANT. The idea is to ensure it tries a select - * with the same bits the initial thread had set. - */ -#define POLL_WANT 0x1 -#define POLL_DONE 0x2 - -/* - * This is the thread ID of the notifier thread that does select. - */ -static Tcl_ThreadId notifierThread; - -#endif - -/* - * Static routines defined in this file. - */ - -#ifdef TCL_THREADS -static void NotifierThreadProc _ANSI_ARGS_((ClientData clientData)); -#endif -static int FileHandlerEventProc _ANSI_ARGS_((Tcl_Event *evPtr, - int flags)); - -/* - *---------------------------------------------------------------------- - * - * Tcl_InitNotifier -- - * - * Initializes the platform specific notifier state. - * - * Results: - * Returns a handle to the notifier state for this thread.. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -ClientData -Tcl_InitNotifier() -{ - ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - -#ifdef TCL_THREADS - tsdPtr->eventReady = 0; - - /* - * Start the Notifier thread if necessary. - */ - - Tcl_MutexLock(¬ifierMutex); - if (notifierCount == 0) { - if (Tcl_CreateThread(¬ifierThread, NotifierThreadProc, NULL, - TCL_THREAD_STACK_DEFAULT, TCL_THREAD_NOFLAGS) != TCL_OK) { - panic("Tcl_InitNotifier: unable to start notifier thread"); - } - } - notifierCount++; - - /* - * Wait for the notifier pipe to be created. - */ - - while (triggerPipe < 0) { - Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); - } - - Tcl_MutexUnlock(¬ifierMutex); -#endif - return (ClientData) tsdPtr; -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_FinalizeNotifier -- - * - * This function is called to cleanup the notifier state before - * a thread is terminated. - * - * Results: - * None. - * - * Side effects: - * May terminate the background notifier thread if this is the - * last notifier instance. - * - *---------------------------------------------------------------------- - */ - -void -Tcl_FinalizeNotifier(clientData) - ClientData clientData; /* Not used. */ -{ -#ifdef TCL_THREADS - ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - - Tcl_MutexLock(¬ifierMutex); - notifierCount--; - - /* - * 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) { - if (triggerPipe < 0) { - panic("Tcl_FinalizeNotifier: 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] - */ - write(triggerPipe, "q", 1); - close(triggerPipe); - - Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); - } - - /* - * Clean up any synchronization objects in the thread local storage. - */ - - Tcl_ConditionFinalize(&(tsdPtr->waitCV)); - - Tcl_MutexUnlock(¬ifierMutex); -#endif -} - -/* - *---------------------------------------------------------------------- - * - * 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: - * Signals the notifier condition variable for the specified - * notifier. - * - *---------------------------------------------------------------------- - */ - -void -Tcl_AlertNotifier(clientData) - ClientData clientData; -{ -#ifdef TCL_THREADS - ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData; - Tcl_MutexLock(¬ifierMutex); - tsdPtr->eventReady = 1; - Tcl_ConditionNotify(&tsdPtr->waitCV); - Tcl_MutexUnlock(¬ifierMutex); -#endif -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_SetTimer -- - * - * This procedure 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(timePtr) - Tcl_Time *timePtr; /* Timeout value, may be NULL. */ -{ - /* - * 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. - */ - - if (tclStubs.tcl_SetTimer != Tcl_SetTimer) { - tclStubs.tcl_SetTimer(timePtr); - } -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_ServiceModeHook -- - * - * This function is invoked whenever the service mode changes. - * - * Results: - * None. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -void -Tcl_ServiceModeHook(mode) - int mode; /* Either TCL_SERVICE_ALL, or - * TCL_SERVICE_NONE. */ -{ -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_CreateFileHandler -- - * - * This procedure registers a file handler with the select notifier. - * - * Results: - * None. - * - * Side effects: - * Creates a new file handler structure. - * - *---------------------------------------------------------------------- - */ - -void -Tcl_CreateFileHandler(fd, mask, proc, clientData) - int fd; /* Handle of stream to watch. */ - int mask; /* OR'ed combination of TCL_READABLE, - * TCL_WRITABLE, and TCL_EXCEPTION: - * indicates conditions under which - * proc should be called. */ - Tcl_FileProc *proc; /* Procedure to call for each - * selected event. */ - ClientData clientData; /* Arbitrary data to pass to proc. */ -{ - ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - FileHandler *filePtr; - int index, bit; - - if (tclStubs.tcl_CreateFileHandler != Tcl_CreateFileHandler) { - tclStubs.tcl_CreateFileHandler(fd, mask, proc, clientData); - return; - } - - for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; - filePtr = filePtr->nextPtr) { - if (filePtr->fd == fd) { - break; - } - } - if (filePtr == NULL) { - filePtr = (FileHandler*) ckalloc(sizeof(FileHandler)); - filePtr->fd = fd; - filePtr->readyMask = 0; - filePtr->nextPtr = tsdPtr->firstFileHandlerPtr; - tsdPtr->firstFileHandlerPtr = filePtr; - } - filePtr->proc = proc; - filePtr->clientData = clientData; - filePtr->mask = mask; - - /* - * Update the check masks for this file. - */ - - index = fd/(NBBY*sizeof(fd_mask)); - bit = 1 << (fd%(NBBY*sizeof(fd_mask))); - if (mask & TCL_READABLE) { - tsdPtr->checkMasks[index] |= bit; - } else { - tsdPtr->checkMasks[index] &= ~bit; - } - if (mask & TCL_WRITABLE) { - (tsdPtr->checkMasks+MASK_SIZE)[index] |= bit; - } else { - (tsdPtr->checkMasks+MASK_SIZE)[index] &= ~bit; - } - if (mask & TCL_EXCEPTION) { - (tsdPtr->checkMasks+2*(MASK_SIZE))[index] |= bit; - } else { - (tsdPtr->checkMasks+2*(MASK_SIZE))[index] &= ~bit; - } - if (tsdPtr->numFdBits <= fd) { - tsdPtr->numFdBits = fd+1; - } -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_DeleteFileHandler -- - * - * Cancel a previously-arranged callback arrangement for - * a file. - * - * Results: - * None. - * - * Side effects: - * If a callback was previously registered on file, remove it. - * - *---------------------------------------------------------------------- - */ - -void -Tcl_DeleteFileHandler(fd) - int fd; /* Stream id for which to remove callback procedure. */ -{ - FileHandler *filePtr, *prevPtr; - int index, bit, i; - unsigned long flags; - ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - - if (tclStubs.tcl_DeleteFileHandler != Tcl_DeleteFileHandler) { - tclStubs.tcl_DeleteFileHandler(fd); - return; - } - - /* - * Find the entry for the given file (and return if there isn't one). - */ - - for (prevPtr = NULL, filePtr = tsdPtr->firstFileHandlerPtr; ; - prevPtr = filePtr, filePtr = filePtr->nextPtr) { - if (filePtr == NULL) { - return; - } - if (filePtr->fd == fd) { - break; - } - } - - /* - * Update the check masks for this file. - */ - - index = fd/(NBBY*sizeof(fd_mask)); - bit = 1 << (fd%(NBBY*sizeof(fd_mask))); - - if (filePtr->mask & TCL_READABLE) { - tsdPtr->checkMasks[index] &= ~bit; - } - if (filePtr->mask & TCL_WRITABLE) { - (tsdPtr->checkMasks+MASK_SIZE)[index] &= ~bit; - } - if (filePtr->mask & TCL_EXCEPTION) { - (tsdPtr->checkMasks+2*(MASK_SIZE))[index] &= ~bit; - } - - /* - * Find current max fd. - */ - - if (fd+1 == tsdPtr->numFdBits) { - for (tsdPtr->numFdBits = 0; index >= 0; index--) { - flags = tsdPtr->checkMasks[index] - | (tsdPtr->checkMasks+MASK_SIZE)[index] - | (tsdPtr->checkMasks+2*(MASK_SIZE))[index]; - if (flags) { - for (i = (NBBY*sizeof(fd_mask)); i > 0; i--) { - if (flags & (((unsigned long)1) << (i-1))) { - break; - } - } - tsdPtr->numFdBits = index * (NBBY*sizeof(fd_mask)) + i; - break; - } - } - } - - /* - * Clean up information in the callback record. - */ - - if (prevPtr == NULL) { - tsdPtr->firstFileHandlerPtr = filePtr->nextPtr; - } else { - prevPtr->nextPtr = filePtr->nextPtr; - } - ckfree((char *) filePtr); -} - -/* - *---------------------------------------------------------------------- - * - * FileHandlerEventProc -- - * - * This procedure is called by Tcl_ServiceEvent when a file event - * reaches the front of the event queue. This procedure 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 procedure does. - * - *---------------------------------------------------------------------- - */ - -static int -FileHandlerEventProc(evPtr, flags) - 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; -} - -/* - *---------------------------------------------------------------------- - * - * Tcl_WaitForEvent -- - * - * This function is called by Tcl_DoOneEvent to wait for new - * events on the message queue. If the block time is 0, then - * Tcl_WaitForEvent just polls without blocking. - * - * Results: - * Returns -1 if the select would block forever, otherwise - * returns 0. - * - * Side effects: - * Queues file events that are detected by the select. - * - *---------------------------------------------------------------------- - */ - -int -Tcl_WaitForEvent(timePtr) - Tcl_Time *timePtr; /* Maximum block time, or NULL. */ -{ - FileHandler *filePtr; - FileHandlerEvent *fileEvPtr; - struct timeval timeout, *timeoutPtr; - int bit, index, mask; -#ifdef TCL_THREADS - int waitForFiles; -#else - int numFound; -#endif - ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); - - if (tclStubs.tcl_WaitForEvent != Tcl_WaitForEvent) { - return tclStubs.tcl_WaitForEvent(timePtr); - } - - /* - * 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. - */ - - if (timePtr) { - timeout.tv_sec = timePtr->sec; - timeout.tv_usec = timePtr->usec; - timeoutPtr = &timeout; -#ifndef TCL_THREADS - } else if (tsdPtr->numFdBits == 0) { - /* - * If there are no threads, no timeout, and no fds registered, - * then there are no events possible and we must avoid deadlock. - * Note that this is not entirely correct because there might - * be a signal that could interrupt the select call, but we - * don't handle that case if we aren't using threads. - */ - - return -1; -#endif - } else { - timeoutPtr = NULL; - } - -#ifdef TCL_THREADS - /* - * Place this thread on the list of interested threads, signal the - * notifier thread, and wait for a response or a timeout. - */ - - Tcl_MutexLock(¬ifierMutex); - - waitForFiles = (tsdPtr->numFdBits > 0); - if (timePtr != NULL && timePtr->sec == 0 && timePtr->usec == 0) { - /* - * Cannot emulate a polling select with a polling condition variable. - * Instead, pretend to wait for files and tell the notifier - * thread what we are doing. The notifier thread makes sure - * it goes through select with its select mask in the same state - * as ours currently is. We block until that happens. - */ - - waitForFiles = 1; - tsdPtr->pollState = POLL_WANT; - timePtr = NULL; - } else { - tsdPtr->pollState = 0; - } - - if (waitForFiles) { - /* - * Add the ThreadSpecificData structure of this thread to the list - * of ThreadSpecificData structures of all threads that are waiting - * on file events. - */ - - - tsdPtr->nextPtr = waitingListPtr; - if (waitingListPtr) { - waitingListPtr->prevPtr = tsdPtr; - } - tsdPtr->prevPtr = 0; - waitingListPtr = tsdPtr; - tsdPtr->onList = 1; - - write(triggerPipe, "", 1); - } - - memset((VOID *) tsdPtr->readyMasks, 0, 3*MASK_SIZE*sizeof(fd_mask)); - - if (!tsdPtr->eventReady) { - Tcl_ConditionWait(&tsdPtr->waitCV, ¬ifierMutex, timePtr); - } - tsdPtr->eventReady = 0; - - if (waitForFiles && tsdPtr->onList) { - /* - * Remove the ThreadSpecificData structure of this thread from the - * waiting list. Alert the notifier thread to recompute its select - * masks - skipping this caused a hang when trying to close a pipe - * which the notifier thread was still doing a select on. - */ - - 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; - write(triggerPipe, "", 1); - } - - -#else - memcpy((VOID *) tsdPtr->readyMasks, (VOID *) tsdPtr->checkMasks, - 3*MASK_SIZE*sizeof(fd_mask)); - numFound = select(tsdPtr->numFdBits, - (SELECT_MASK *) &tsdPtr->readyMasks[0], - (SELECT_MASK *) &tsdPtr->readyMasks[MASK_SIZE], - (SELECT_MASK *) &tsdPtr->readyMasks[2*MASK_SIZE], timeoutPtr); - - /* - * Some systems don't clear the masks after an error, so - * we have to do it here. - */ - - if (numFound == -1) { - memset((VOID *) tsdPtr->readyMasks, 0, 3*MASK_SIZE*sizeof(fd_mask)); - } -#endif - - /* - * Queue all detected file events before returning. - */ - - for (filePtr = tsdPtr->firstFileHandlerPtr; (filePtr != NULL); - filePtr = filePtr->nextPtr) { - index = filePtr->fd / (NBBY*sizeof(fd_mask)); - bit = 1 << (filePtr->fd % (NBBY*sizeof(fd_mask))); - mask = 0; - - if (tsdPtr->readyMasks[index] & bit) { - mask |= TCL_READABLE; - } - if ((tsdPtr->readyMasks+MASK_SIZE)[index] & bit) { - mask |= TCL_WRITABLE; - } - if ((tsdPtr->readyMasks+2*(MASK_SIZE))[index] & bit) { - mask |= TCL_EXCEPTION; - } - - if (!mask) { - continue; - } - - /* - * Don't bother to queue an event if the mask was previously - * non-zero since an event must still be on the queue. - */ - - if (filePtr->readyMask == 0) { - fileEvPtr = (FileHandlerEvent *) ckalloc( - sizeof(FileHandlerEvent)); - fileEvPtr->header.proc = FileHandlerEventProc; - fileEvPtr->fd = filePtr->fd; - Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); - } - filePtr->readyMask = mask; - } -#ifdef TCL_THREADS - Tcl_MutexUnlock(¬ifierMutex); -#endif - return 0; -} - -#ifdef TCL_THREADS -/* - *---------------------------------------------------------------------- - * - * NotifierThreadProc -- - * - * This routine is the initial (and only) function executed by the - * special notifier thread. Its job is to wait for file descriptors - * to become readable or writable or to have an exception condition - * and then to notify other threads who are interested in this - * information by signalling a condition variable. Other threads - * can signal this notifier thread of a change in their interests - * by writing a single byte to a special pipe that the notifier - * thread is monitoring. - * - * Result: - * None. Once started, this routine never exits. It dies with - * the overall process. - * - * Side effects: - * The trigger pipe used to signal the notifier thread is created - * when the notifier thread first starts. - * - *---------------------------------------------------------------------- - */ - -static void -NotifierThreadProc(clientData) - ClientData clientData; /* Not used. */ -{ - ThreadSpecificData *tsdPtr; - fd_mask masks[3*MASK_SIZE]; - long *maskPtr = (long *)masks; /* masks[] cast to type long[] */ - int fds[2]; - int i, status, index, bit, numFdBits, found, receivePipe, word; - struct timeval poll = {0., 0.}, *timePtr; - int maskSize = 3 * ((MASK_SIZE) / sizeof(long)) * sizeof(fd_mask); - char buf[2]; - - if (pipe(fds) != 0) { - panic("NotifierThreadProc: could not create trigger pipe."); - } - - receivePipe = fds[0]; - -#ifndef USE_FIONBIO - status = fcntl(receivePipe, F_GETFL); - status |= O_NONBLOCK; - if (fcntl(receivePipe, F_SETFL, status) < 0) { - panic("NotifierThreadProc: could not make receive pipe non blocking."); - } - status = fcntl(fds[1], F_GETFL); - status |= O_NONBLOCK; - if (fcntl(fds[1], F_SETFL, status) < 0) { - panic("NotifierThreadProc: could not make trigger pipe non blocking."); - } -#else - if (ioctl(receivePipe, (int) FIONBIO, &status) < 0) { - panic("NotifierThreadProc: could not make receive pipe non blocking."); - } - if (ioctl(fds[1], (int) FIONBIO, &status) < 0) { - panic("NotifierThreadProc: could not make trigger pipe non blocking."); - } -#endif - - /* - * Install the write end of the pipe into the global variable. - */ - - Tcl_MutexLock(¬ifierMutex); - triggerPipe = fds[1]; - - /* - * Signal any threads that are waiting. - */ - - Tcl_ConditionNotify(¬ifierCV); - Tcl_MutexUnlock(¬ifierMutex); - - /* - * Look for file events and report them to interested threads. - */ - - while (1) { - /* - * Set up the select mask to include the receive pipe. - */ - - memset((VOID *)masks, 0, 3*MASK_SIZE*sizeof(fd_mask)); - numFdBits = receivePipe + 1; - index = receivePipe / (NBBY*sizeof(fd_mask)); - bit = 1 << (receivePipe % (NBBY*sizeof(fd_mask))); - masks[index] |= bit; - - /* - * Add in the check masks from all of the waiting notifiers. - */ - - Tcl_MutexLock(¬ifierMutex); - timePtr = NULL; - for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { - for (i = 0; i < maskSize; i++) { - maskPtr[i] |= ((long*)tsdPtr->checkMasks)[i]; - } - if (tsdPtr->numFdBits > numFdBits) { - numFdBits = tsdPtr->numFdBits; - } - if (tsdPtr->pollState & POLL_WANT) { - /* - * Here we make sure we go through select() with the same - * mask bits that were present when the thread tried to poll. - */ - - tsdPtr->pollState |= POLL_DONE; - timePtr = &poll; - } - } - Tcl_MutexUnlock(¬ifierMutex); - - maskSize = 3 * ((MASK_SIZE) / sizeof(long)) * sizeof(fd_mask); - - if (select(numFdBits, (SELECT_MASK *) &masks[0], - (SELECT_MASK *) &masks[MASK_SIZE], - (SELECT_MASK *) &masks[2*MASK_SIZE], timePtr) == -1) { - /* - * Try again immediately on an error. - */ - - continue; - } - - /* - * Alert any threads that are waiting on a ready file descriptor. - */ - - Tcl_MutexLock(¬ifierMutex); - for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { - found = 0; - - for (i = 0; i < maskSize; i++) { - word = maskPtr[i] & ((long*)tsdPtr->checkMasks)[i]; - found |= word; - (((long*)(tsdPtr->readyMasks))[i]) = word; - } - if (found || (tsdPtr->pollState & POLL_DONE)) { - tsdPtr->eventReady = 1; - Tcl_ConditionNotify(&tsdPtr->waitCV); - if (tsdPtr->onList) { - /* - * Remove the ThreadSpecificData structure of this - * thread from the waiting list. This prevents us from - * continuously spining on select 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; - } - } - } - Tcl_MutexUnlock(¬ifierMutex); - - /* - * Consume the next byte from the notifier pipe if the pipe was - * readable. Note that there may be multiple bytes pending, but - * to avoid a race condition we only read one at a time. - */ - - if (masks[index] & bit) { - i = read(receivePipe, buf, 1); - - if ((i == 0) || ((i == 1) && (buf[0] == 'q'))) { - /* - * Someone closed the write end of the pipe or sent us a - * Quit message [Bug: 4139] and then closed the write end - * of the pipe so we need to shut down the notifier thread. - */ - - break; - } - } - } - - /* - * Clean up the read end of the pipe and signal any threads waiting on - * termination of the notifier thread. - */ - - close(receivePipe); - Tcl_MutexLock(¬ifierMutex); - triggerPipe = -1; - Tcl_ConditionNotify(¬ifierCV); - Tcl_MutexUnlock(¬ifierMutex); -} -#endif |