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Diffstat (limited to 'unix/tclKqueueNotfy.c')
| -rw-r--r-- | unix/tclKqueueNotfy.c | 853 |
1 files changed, 853 insertions, 0 deletions
diff --git a/unix/tclKqueueNotfy.c b/unix/tclKqueueNotfy.c new file mode 100644 index 0000000..99d794e --- /dev/null +++ b/unix/tclKqueueNotfy.c @@ -0,0 +1,853 @@ +/* + * tclKqueueNotfy.c -- + * + * This file contains the implementation of the kqueue()-based + * DragonFly/Free/Net/OpenBSD-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. + * Copyright (c) 2016 Lucio Andrés 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 "tclInt.h" +#ifndef HAVE_COREFOUNDATION /* Darwin/Mac OS X CoreFoundation notifier is + * in tclMacOSXNotify.c */ +#if defined(NOTIFIER_KQUEUE) && TCL_THREADS + +#include <signal.h> +#include <sys/types.h> +#include <sys/event.h> +#include <sys/queue.h> +#include <sys/time.h> + +/* + * This structure is used to keep track of the notifier info for a registered + * file. + */ + +struct PlatformEventData; +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; /* Function 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. */ + LIST_ENTRY(FileHandler) readyNode; + /* Next/previous in list of FileHandlers asso- + * ciated with regular files (S_IFREG) that are + * ready for I/O. */ + struct PlatformEventData *pedPtr; + /* Pointer to PlatformEventData associating this + * FileHandler with kevent(2) events. */ +} FileHandler; + +/* + * The following structure associates a FileHandler and the thread that owns + * it with the file descriptors of interest and their event masks passed to + * kevent(2) and their corresponding event(s) returned by kevent(2). + */ + +struct ThreadSpecificData; +struct PlatformEventData { + FileHandler *filePtr; + struct ThreadSpecificData *tsdPtr; +}; + +/* + * The following structure is what is added to the Tcl event queue when file + * handlers are ready to fire. + */ + +typedef struct { + 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 + * kqueue based implementation of the Tcl notifier. One of these structures is + * created for each thread that is using the notifier. + */ + +LIST_HEAD(PlatformReadyFileHandlerList, FileHandler); +typedef struct ThreadSpecificData { + FileHandler *firstFileHandlerPtr; + /* Pointer to head of file handler list. */ + struct PlatformReadyFileHandlerList firstReadyFileHandlerPtr; + /* Pointer to head of list of FileHandlers + * associated with regular files (S_IFREG) + * that are ready for I/O. */ + pthread_mutex_t notifierMutex; + /* Mutex protecting notifier termination in + * PlatformEventsFinalize. */ + int triggerPipe[2]; /* pipe(2) used by other threads to wake + * up this thread for inter-thread IPC. */ + int eventsFd; /* kqueue(2) file descriptor used to wait for + * fds. */ + struct kevent *readyEvents; /* Pointer to at most maxReadyEvents events + * returned by kevent(2). */ + size_t maxReadyEvents; /* Count of kevents in readyEvents. */ +} ThreadSpecificData; + +static Tcl_ThreadDataKey dataKey; + +/* + * Forward declarations of internal functions. + */ + +static void PlatformEventsControl(FileHandler *filePtr, + ThreadSpecificData *tsdPtr, int op, int isNew); +static void PlatformEventsFinalize(void); +static void PlatformEventsInit(void); +static int PlatformEventsTranslate(struct kevent *eventPtr); +static int PlatformEventsWait(struct kevent *events, + size_t numEvents, struct timeval *timePtr); + +#include "tclUnixNotfy.c" + +/* + *---------------------------------------------------------------------- + * + * Tcl_InitNotifier -- + * + * Initializes the platform specific notifier state. + * + * Results: + * Returns a handle to the notifier state for this thread. + * + * Side effects: + * If no initNotifierProc notifier hook exists, PlatformEventsInit + * is called. + * + *---------------------------------------------------------------------- + */ + +ClientData +Tcl_InitNotifier(void) +{ + if (tclNotifierHooks.initNotifierProc) { + return tclNotifierHooks.initNotifierProc(); + } else { + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + PlatformEventsInit(); + return tsdPtr; + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_FinalizeNotifier -- + * + * This function is called to cleanup the notifier state before a thread + * is terminated. + * + * Results: + * None. + * + * Side effects: + * If no finalizeNotifierProc notifier hook exists, PlatformEvents- + * Finalize is called. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_FinalizeNotifier( + ClientData clientData) /* Not used. */ +{ + if (tclNotifierHooks.finalizeNotifierProc) { + tclNotifierHooks.finalizeNotifierProc(clientData); + return; + } else { + PlatformEventsFinalize(); + } +} + +/* + *---------------------------------------------------------------------- + * + * PlatformEventsControl -- + * + * This function registers interest for the file descriptor and the mask + * of TCL_* bits associated with filePtr on the kqueue file descriptor + * associated with tsdPtr. + * + * Future calls to kevent will return filePtr and tsdPtr alongside with + * the event registered here via the PlatformEventData struct. + * + * Results: + * None. + * + * Side effects: + * - If adding a new file descriptor, a PlatformEventData struct will be + * allocated and associated with filePtr. + * - fstat is called on the file descriptor; if it is associated with + * a regular file (S_IFREG,) filePtr is considered to be ready for I/O + * and added to or deleted from the corresponding list in tsdPtr. + * - If it is not associated with a regular file, the file descriptor is + * added, modified concerning its mask of events of interest, or + * deleted from the epoll file descriptor of the calling thread. + * - If deleting a file descriptor, kevent(2) is called twice specifying + * EVFILT_READ first and then EVFILT_WRITE (see note below.) + * + *---------------------------------------------------------------------- + */ + +void +PlatformEventsControl( + FileHandler *filePtr, + ThreadSpecificData *tsdPtr, + int op, + int isNew) +{ + int numChanges; + struct kevent changeList[2]; + struct PlatformEventData *newPedPtr; + struct stat fdStat; + + if (isNew) { + newPedPtr = ckalloc(sizeof(*newPedPtr)); + newPedPtr->filePtr = filePtr; + newPedPtr->tsdPtr = tsdPtr; + filePtr->pedPtr = newPedPtr; + } + + /* + * N.B. As discussed in Tcl_WaitForEvent(), kqueue(2) does not reproduce + * the `always ready' {select,poll}(2) behaviour for regular files + * (S_IFREG) prior to FreeBSD 11.0-RELEASE. Therefore, filePtr is in these + * cases simply added or deleted from the list of FileHandlers associated + * with regular files belonging to tsdPtr. + */ + + if (fstat(filePtr->fd, &fdStat) == -1) { + Tcl_Panic("fstat: %s", strerror(errno)); + } else if ((fdStat.st_mode & S_IFMT) == S_IFREG) { + switch (op) { + case EV_ADD: + if (isNew) { + LIST_INSERT_HEAD(&tsdPtr->firstReadyFileHandlerPtr, filePtr, + readyNode); + } + break; + case EV_DELETE: + LIST_REMOVE(filePtr, readyNode); + break; + } + return; + } + + numChanges = 0; + switch (op) { + case EV_ADD: + if (filePtr->mask & (TCL_READABLE | TCL_EXCEPTION)) { + EV_SET(&changeList[numChanges], (uintptr_t)filePtr->fd, + EVFILT_READ, op, 0, 0, filePtr->pedPtr); + numChanges++; + } + if (filePtr->mask & TCL_WRITABLE) { + EV_SET(&changeList[numChanges], (uintptr_t)filePtr->fd, + EVFILT_WRITE, op, 0, 0, filePtr->pedPtr); + numChanges++; + } + if (numChanges) { + if (kevent(tsdPtr->eventsFd, changeList, numChanges, NULL, 0, + NULL) == -1) { + Tcl_Panic("kevent: %s", strerror(errno)); + } + } + break; + case EV_DELETE: + /* + * N.B. kqueue(2) has separate filters for readability and writability + * fd events. We therefore need to ensure that fds are ompletely + * removed from the kqueue(2) fd when deleting. This is exacerbated + * by changes to filePtr->mask w/o calls to PlatforEventsControl() + * after e.g. an exec(3) in a child process. + * + * As one of these calls can fail, two separate kevent(2) calls are + * made for EVFILT_{READ,WRITE}. + */ + EV_SET(&changeList[0], (uintptr_t)filePtr->fd, EVFILT_READ, op, 0, 0, + NULL); + if ((kevent(tsdPtr->eventsFd, changeList, 1, NULL, 0, NULL) == -1) + && (errno != ENOENT)) { + Tcl_Panic("kevent: %s", strerror(errno)); + } + EV_SET(&changeList[0], (uintptr_t)filePtr->fd, EVFILT_WRITE, op, 0, 0, + NULL); + if ((kevent(tsdPtr->eventsFd, changeList, 1, NULL, 0, NULL) == -1) + && (errno != ENOENT)) { + Tcl_Panic("kevent: %s", strerror(errno)); + } + break; + } +} + +/* + *---------------------------------------------------------------------- + * + * PlatformEventsFinalize -- + * + * This function closes the pipe and the kqueue file descriptors and + * frees the kevent structs owned by the thread of the caller. The above + * operations are protected by tsdPtr->notifierMutex, which is destroyed + * thereafter. + * + * Results: + * None. + * + * Side effects: + * While tsdPtr->notifierMutex is held: + * The per-thread pipe(2) fds are closed, if non-zero, and set to -1. + * The per-thread kqueue(2) fd is closed, if non-zero, and set to 0. + * The per-thread kevent structs are freed, if any, and set to 0. + * + * tsdPtr->notifierMutex is destroyed. + * + *---------------------------------------------------------------------- + */ + +void +PlatformEventsFinalize( + void) +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + pthread_mutex_lock(&tsdPtr->notifierMutex); + if (tsdPtr->triggerPipe[0]) { + close(tsdPtr->triggerPipe[0]); + tsdPtr->triggerPipe[0] = -1; + } + if (tsdPtr->triggerPipe[1]) { + close(tsdPtr->triggerPipe[1]); + tsdPtr->triggerPipe[1] = -1; + } + if (tsdPtr->eventsFd > 0) { + close(tsdPtr->eventsFd); + tsdPtr->eventsFd = 0; + } + if (tsdPtr->readyEvents) { + ckfree(tsdPtr->readyEvents); + tsdPtr->maxReadyEvents = 0; + } + pthread_mutex_unlock(&tsdPtr->notifierMutex); + if ((errno = pthread_mutex_destroy(&tsdPtr->notifierMutex))) { + Tcl_Panic("pthread_mutex_destroy: %s", strerror(errno)); + } +} + +/* + *---------------------------------------------------------------------- + * + * PlatformEventsInit -- + * + * This function abstracts creating a kqueue fd via the kqueue system + * call and allocating memory for the kevents structs in tsdPtr for the + * thread of the caller. + * + * Results: + * None. + * + * Side effects: + * The following per-thread entities are initialised: + * - notifierMutex is initialised. + * - The pipe(2) is created; fcntl(2) is called on both fds to set + * FD_CLOEXEC and O_NONBLOCK. + * - The kqueue(2) fd is created; fcntl(2) is called on it to set + * FD_CLOEXEC. + * - A FileHandler struct is allocated and initialised for the event- + * fd(2), registering interest for TCL_READABLE on it via Platform- + * EventsControl(). + * - readyEvents and maxReadyEvents are initialised with 512 kevents. + * + *---------------------------------------------------------------------- + */ + +void +PlatformEventsInit(void) +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + int i, fdFl; + FileHandler *filePtr; + + errno = pthread_mutex_init(&tsdPtr->notifierMutex, NULL); + if (errno) { + Tcl_Panic("Tcl_InitNotifier: %s", "could not create mutex"); + } + if (pipe(tsdPtr->triggerPipe) != 0) { + Tcl_Panic("Tcl_InitNotifier: %s", "could not create trigger pipe"); + } else for (i = 0; i < 2; i++) { + if (fcntl(tsdPtr->triggerPipe[i], F_SETFD, FD_CLOEXEC) == -1) { + Tcl_Panic("fcntl: %s", strerror(errno)); + } else { + fdFl = fcntl(tsdPtr->triggerPipe[i], F_GETFL); + fdFl |= O_NONBLOCK; + } + if (fcntl(tsdPtr->triggerPipe[i], F_SETFL, fdFl) == -1) { + Tcl_Panic("fcntl: %s", strerror(errno)); + } + } + if ((tsdPtr->eventsFd = kqueue()) == -1) { + Tcl_Panic("kqueue: %s", strerror(errno)); + } else if (fcntl(tsdPtr->eventsFd, F_SETFD, FD_CLOEXEC) == -1) { + Tcl_Panic("fcntl: %s", strerror(errno)); + } + filePtr = ckalloc(sizeof(*filePtr)); + filePtr->fd = tsdPtr->triggerPipe[0]; + filePtr->mask = TCL_READABLE; + PlatformEventsControl(filePtr, tsdPtr, EV_ADD, 1); + if (!tsdPtr->readyEvents) { + tsdPtr->maxReadyEvents = 512; + tsdPtr->readyEvents = ckalloc( + tsdPtr->maxReadyEvents * sizeof(tsdPtr->readyEvents[0])); + } + LIST_INIT(&tsdPtr->firstReadyFileHandlerPtr); +} + +/* + *---------------------------------------------------------------------- + * + * PlatformEventsTranslate -- + * + * This function translates the platform-specific mask of returned + * events in eventPtr to a mask of TCL_* bits. + * + * Results: + * Returns the translated mask. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +int +PlatformEventsTranslate( + struct kevent *eventPtr) +{ + int mask; + + mask = 0; + if (eventPtr->filter == EVFILT_READ) { + mask |= TCL_READABLE; + if (eventPtr->flags & EV_ERROR) { + mask |= TCL_EXCEPTION; + } + } + if (eventPtr->filter == EVFILT_WRITE) { + mask |= TCL_WRITABLE; + if (eventPtr->flags & EV_ERROR) { + mask |= TCL_EXCEPTION; + } + } + return mask; +} + +/* + *---------------------------------------------------------------------- + * + * PlatformEventsWait -- + * + * This function abstracts waiting for I/O events via the kevent system + * call. + * + * Results: + * Returns -1 if kevent failed. Returns 0 if polling and if no events + * became available whilst polling. Returns a pointer to and the count of + * all returned events in all other cases. + * + * Side effects: + * gettimeofday(2), kevent(2), and gettimeofday(2) are called, in the + * specified order. + * If timePtr specifies a positive value, it is updated to reflect the + * amount of time that has passed; if its value would {under, over}flow, + * it is set to zero. + * + *---------------------------------------------------------------------- + */ + +int +PlatformEventsWait( + struct kevent *events, + size_t numEvents, + struct timeval *timePtr) +{ + int numFound; + struct timeval tv0, tv1, tv_delta; + struct timespec timeout, *timeoutPtr; + + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + /* + * If timePtr is NULL, kevent(2) will wait indefinitely. If it specifies a + * timeout of {0,0}, kevent(2) will poll. Otherwise, the timeout will + * simply be converted to a timespec. + */ + + if (!timePtr) { + timeoutPtr = NULL; + } else if (!timePtr->tv_sec && !timePtr->tv_usec) { + timeout.tv_sec = 0; + timeout.tv_nsec = 0; + timeoutPtr = &timeout; + } else { + timeout.tv_sec = timePtr->tv_sec; + timeout.tv_nsec = timePtr->tv_usec * 1000; + timeoutPtr = &timeout; + } + + /* + * Call (and possibly block on) kevent(2) and substract the delta of + * gettimeofday(2) before and after the call from timePtr if the latter is + * not NULL. Return the number of events returned by kevent(2). + */ + + gettimeofday(&tv0, NULL); + numFound = kevent(tsdPtr->eventsFd, NULL, 0, events, (int) numEvents, + timeoutPtr); + gettimeofday(&tv1, NULL); + if (timePtr && (timePtr->tv_sec && timePtr->tv_usec)) { + timersub(&tv1, &tv0, &tv_delta); + if (!timercmp(&tv_delta, timePtr, >)) { + timersub(timePtr, &tv_delta, timePtr); + } else { + timePtr->tv_sec = 0; + timePtr->tv_usec = 0; + } + } + return numFound; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_CreateFileHandler -- + * + * This function registers a file handler with the kqueue notifier + * of the thread of the caller. + * + * Results: + * None. + * + * Side effects: + * Creates a new file handler structure. + * PlatformEventsControl() is called for the new file handler structure. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_CreateFileHandler( + 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, /* Function to call for each selected + * event. */ + ClientData clientData) /* Arbitrary data to pass to proc. */ +{ + int isNew; + + if (tclNotifierHooks.createFileHandlerProc) { + tclNotifierHooks.createFileHandlerProc(fd, mask, proc, clientData); + return; + } else { + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + FileHandler *filePtr; + + for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; + filePtr = filePtr->nextPtr) { + if (filePtr->fd == fd) { + break; + } + } + if (filePtr == NULL) { + filePtr = ckalloc(sizeof(FileHandler)); + filePtr->fd = fd; + filePtr->readyMask = 0; + filePtr->nextPtr = tsdPtr->firstFileHandlerPtr; + tsdPtr->firstFileHandlerPtr = filePtr; + isNew = 1; + } else { + isNew = 0; + } + filePtr->proc = proc; + filePtr->clientData = clientData; + filePtr->mask = mask; + + PlatformEventsControl(filePtr, tsdPtr, EV_ADD, isNew); + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteFileHandler -- + * + * Cancel a previously-arranged callback arrangement for a file on the + * kqueue of the thread of the caller. + * + * Results: + * None. + * + * Side effects: + * If a callback was previously registered on file, remove it. + * PlatformEventsControl() is called for the file handler structure. + * The PlatformEventData struct associated with the new file handler + * structure is freed. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_DeleteFileHandler( + int fd) /* Stream id for which to remove callback + * function. */ +{ + if (tclNotifierHooks.deleteFileHandlerProc) { + tclNotifierHooks.deleteFileHandlerProc(fd); + return; + } else { + FileHandler *filePtr, *prevPtr; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + /* + * 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. + */ + + PlatformEventsControl(filePtr, tsdPtr, EV_DELETE, 0); + if (filePtr->pedPtr) { + ckfree(filePtr->pedPtr); + } + + /* + * Clean up information in the callback record. + */ + + if (prevPtr == NULL) { + tsdPtr->firstFileHandlerPtr = filePtr->nextPtr; + } else { + prevPtr->nextPtr = filePtr->nextPtr; + } + ckfree(filePtr); + } +} + +/* + *---------------------------------------------------------------------- + * + * 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. + * + * The waiting logic is implemented in PlatformEventsWait. + * + * Results: + * Returns -1 if PlatformEventsWait() would block forever, otherwise + * returns 0. + * + * Side effects: + * Queues file events that are detected by PlatformEventsWait(). + * + *---------------------------------------------------------------------- + */ + +int +Tcl_WaitForEvent( + const Tcl_Time *timePtr) /* Maximum block time, or NULL. */ +{ + if (tclNotifierHooks.waitForEventProc) { + return tclNotifierHooks.waitForEventProc(timePtr); + } else { + FileHandler *filePtr; + int mask; + Tcl_Time vTime; + /* + * Impl. notes: timeout & timeoutPtr are used if, and only if threads + * are not enabled. They are the arguments for the regular epoll_wait() + * used when the core is not thread-enabled. + */ + + struct timeval timeout, *timeoutPtr; + int numFound, numEvent; + struct PlatformEventData *pedPtr; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + int numQueued; + ssize_t i; + char buf[1]; + + /* + * 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 != NULL) { + /* + * TIP #233 (Virtualized Time). Is virtual time in effect? And do + * we actually have something to scale? If yes to both then we + * call the handler to do this scaling. + */ + + if (timePtr->sec != 0 || timePtr->usec != 0) { + vTime = *timePtr; + tclScaleTimeProcPtr(&vTime, tclTimeClientData); + timePtr = &vTime; + } + timeout.tv_sec = timePtr->sec; + timeout.tv_usec = timePtr->usec; + timeoutPtr = &timeout; + } else { + timeoutPtr = NULL; + } + + /* + * Walk the list of FileHandlers associated with regular files + * (S_IFREG) belonging to tsdPtr, queue Tcl events for them, and + * update their mask of events of interest. + * + * kqueue(2), unlike epoll(7), does support regular files, but + * EVFILT_READ only `[r]eturns when the file pointer is not at the end + * of file' as opposed to unconditionally. While FreeBSD 11.0-RELEASE + * adds support for this mode (NOTE_FILE_POLL,) this is not used for + * reasons of compatibility. + * + * Therefore, the behaviour of {select,poll}(2) is simply simulated + * here: fds associated with regular files are added to this list by + * PlatformEventsControl() and processed here before calling (and + * possibly blocking) on PlatformEventsWait(). + */ + + numQueued = 0; + LIST_FOREACH(filePtr, &tsdPtr->firstReadyFileHandlerPtr, readyNode) { + mask = 0; + if (filePtr->mask & TCL_READABLE) { + mask |= TCL_READABLE; + } + if (filePtr->mask & TCL_WRITABLE) { + mask |= TCL_WRITABLE; + } + + /* + * 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) { + FileHandlerEvent *fileEvPtr = + ckalloc(sizeof(FileHandlerEvent)); + + fileEvPtr->header.proc = FileHandlerEventProc; + fileEvPtr->fd = filePtr->fd; + Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); + numQueued++; + } + filePtr->readyMask = mask; + } + + /* + * If any events were queued in the above loop, force PlatformEvents- + * Wait() to poll as there already are events that need to be processed + * at this point. + */ + + if (numQueued) { + timeout.tv_sec = 0; + timeout.tv_usec = 0; + timeoutPtr = &timeout; + } + + /* + * Wait or poll for new events, queue Tcl events for the FileHandlers + * corresponding to them, and update the FileHandlers' mask of events + * of interest registered by the last call to Tcl_CreateFileHandler(). + * + * Events for the trigger pipe are processed here in order to facilitate + * inter-thread IPC. If another thread intends to wake up this thread + * whilst it's blocking on PlatformEventsWait(), it write(2)s to the + * other end of the pipe (see Tcl_AlertNotifier(),) which in turn will + * cause PlatformEventsWait() to return immediately. + */ + + numFound = PlatformEventsWait(tsdPtr->readyEvents, + tsdPtr->maxReadyEvents, timeoutPtr); + for (numEvent = 0; numEvent < numFound; numEvent++) { + pedPtr = (struct PlatformEventData *) + tsdPtr->readyEvents[numEvent].udata; + filePtr = pedPtr->filePtr; + mask = PlatformEventsTranslate(&tsdPtr->readyEvents[numEvent]); + if (filePtr->fd == tsdPtr->triggerPipe[0]) { + i = read(tsdPtr->triggerPipe[0], buf, 1); + if ((i == -1) && (errno != EAGAIN)) { + Tcl_Panic("Tcl_WaitForEvent: read from %p->triggerPipe: %s", + (void *) tsdPtr, strerror(errno)); + } + continue; + } + 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) { + FileHandlerEvent *fileEvPtr = + ckalloc(sizeof(FileHandlerEvent)); + + fileEvPtr->header.proc = FileHandlerEventProc; + fileEvPtr->fd = filePtr->fd; + Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); + } + filePtr->readyMask |= mask; + } + return 0; + } +} + +#endif /* NOTIFIER_KQUEUE && TCL_THREADS */ +#endif /* !HAVE_COREFOUNDATION */ + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |