Re-base to trunk, and get latest code from here: [https://github.com/lalbornoz/tcl/tree/tip458]. Untested.

1 files changed, 810 insertions, 0 deletions

diff --git a/unix/tclEpollNotfy.c b/unix/tclEpollNotfy.c
new file mode 100644
index 0000000..7355564
--- /dev/null
+++ b/unix/tclEpollNotfy.c
@@ -0,0 +1,810 @@
+/*
+ * tclEpollNotfy.c --
+ *
+ *	This file contains the implementation of the epoll()-based
+ *	Linux-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.
+ */
+
+#ifdef NOTIFIER_EPOLL
+
+#define _GNU_SOURCE		/* For pipe2(2) */
+#include "tclInt.h"
+#ifndef HAVE_COREFOUNDATION	/* Darwin/Mac OS X CoreFoundation notifier is
+				 * in tclMacOSXNotify.c */
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <sys/queue.h>
+#include <unistd.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 epoll(7) 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 epoll_ctl(2)
+ * and their corresponding event(s) returned by epoll_wait(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
+ * epoll 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. */
+#ifdef HAVE_EVENTFD
+    int triggerEventFd;		/* eventfd(2) used by other threads to wake
+				 * up this thread for inter-thread IPC. */
+#else
+    int triggerPipe[2];		/* pipe(2) used by other threads to wake
+				 * up this thread for inter-thread IPC. */
+#endif /* HAVE_EVENTFD */
+    int eventsFd;		/* epoll(7) file descriptor used to wait for fds */
+    struct epoll_event *readyEvents;
+				/* Pointer to at most maxReadyEvents events
+				 * returned by epoll_wait(2). */
+    size_t maxReadyEvents;	/* Count of epoll_events in readyEvents. */
+} ThreadSpecificData;
+
+static Tcl_ThreadDataKey dataKey;
+
+void PlatformEventsControl(FileHandler *filePtr, ThreadSpecificData *tsdPtr, int op, int isNew);
+static void PlatformEventsFinalize(void);
+void PlatformEventsInit(void);
+static int PlatformEventsTranslate(struct epoll_event *event);
+static int PlatformEventsWait(struct epoll_event *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 epoll file descriptor
+ *	associated with tsdPtr.
+ *	Future calls to epoll_wait 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.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+PlatformEventsControl(
+	FileHandler *filePtr,
+	ThreadSpecificData *tsdPtr,
+	int op,
+	int isNew)
+{
+    struct epoll_event newEvent;
+    struct PlatformEventData *newPedPtr;
+    struct stat fdStat;
+
+    newEvent.events = 0;
+    if (filePtr->mask & (TCL_READABLE | TCL_EXCEPTION)) {
+	newEvent.events |= EPOLLIN;
+    }
+    if (filePtr->mask & TCL_WRITABLE) {
+	newEvent.events |= EPOLLOUT;
+    }
+    if (isNew) {
+        newPedPtr = ckalloc(sizeof(*newPedPtr));
+        newPedPtr->filePtr = filePtr;
+        newPedPtr->tsdPtr = tsdPtr;
+	filePtr->pedPtr = newPedPtr;
+    }
+    newEvent.data.ptr = filePtr->pedPtr;
+
+    /*
+     * N.B.	As discussed in Tcl_WaitForEvent(), epoll(7) does not sup-
+     *		port regular files (S_IFREG.) 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 EPOLL_CTL_ADD:
+	    if (isNew) {
+		LIST_INSERT_HEAD(&tsdPtr->firstReadyFileHandlerPtr, filePtr, readyNode);
+	    }
+	    break;
+	case EPOLL_CTL_DEL:
+	    LIST_REMOVE(filePtr, readyNode);
+	    break;
+	}
+	return;
+   } else if (epoll_ctl(tsdPtr->eventsFd, op, filePtr->fd, &newEvent) == -1) {
+	Tcl_Panic("epoll_ctl: %s", strerror(errno));
+   }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PlatformEventsFinalize --
+ *
+ *	This function closes the eventfd and the epoll file descriptor and
+ *	frees the epoll_event 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 eventfd(2) is closed, if non-zero, and set to -1.
+ *	The per-thread epoll(7) fd is closed, if non-zero, and set to 0.
+ *	The per-thread epoll_event 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);
+#ifdef HAVE_EVENTFD
+    if (tsdPtr->triggerEventFd) {
+	close(tsdPtr->triggerEventFd);
+	tsdPtr->triggerEventFd = -1;
+    }
+#else
+    if (tsdPtr->triggerPipe[0]) {
+	close(tsdPtr->triggerPipe[0]);
+	tsdPtr->triggerPipe[0] = -1;
+    }
+    if (tsdPtr->triggerPipe[1]) {
+	close(tsdPtr->triggerPipe[1]);
+	tsdPtr->triggerPipe[1] = -1;
+    }
+#endif /* HAVE_EVENTFD */
+    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 epoll_create
+ *	system call and allocating memory for the epoll_event structs in
+ *	tsdPtr for the thread of the caller.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The following per-thread entities are initialised:
+ *	notifierMutex is initialised.
+ *	The eventfd(2) is created w/ EFD_CLOEXEC and EFD_NONBLOCK.
+ *	The epoll(7) fd is created w/ EPOLL_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 epoll_events.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+PlatformEventsInit(
+	void)
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+    FileHandler *filePtr;
+
+    errno = pthread_mutex_init(&tsdPtr->notifierMutex, NULL);
+    if (errno) {
+	Tcl_Panic("Tcl_InitNotifier: %s", "could not create mutex");
+    }
+#ifdef HAVE_EVENTFD
+    if ((tsdPtr->triggerEventFd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK)) <= 0) {
+	Tcl_Panic("Tcl_InitNotifier: %s", "could not create trigger eventfd");
+    }
+#else
+    if (pipe2(tsdPtr->triggerPipe, O_CLOEXEC | O_NONBLOCK) != 0) {
+	Tcl_Panic("Tcl_InitNotifier: %s", "could not create trigger pipe");
+    }
+#endif
+    if ((tsdPtr->eventsFd = epoll_create1(EPOLL_CLOEXEC)) == -1) {
+	Tcl_Panic("epoll_create1: %s", strerror(errno));
+    }
+    filePtr = ckalloc(sizeof(*filePtr));
+#ifdef HAVE_EVENTFD
+    filePtr->fd = tsdPtr->triggerEventFd;
+#else
+    filePtr->fd = tsdPtr->triggerPipe[0];
+#endif
+    filePtr->mask = TCL_READABLE;
+    PlatformEventsControl(filePtr, tsdPtr, EPOLL_CTL_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 epoll_event *eventPtr)
+{
+    int mask;
+
+    mask = 0;
+    if (eventPtr->events & (EPOLLIN | EPOLLHUP)) {
+	mask |= TCL_READABLE;
+    }
+    if (eventPtr->events & EPOLLOUT) {
+	mask |= TCL_WRITABLE;
+    }
+    if (eventPtr->events & EPOLLERR) {
+	mask |= TCL_EXCEPTION;
+    }
+    return mask;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * PlatformEventsWait --
+ *
+ *	This function abstracts waiting for I/O events via epoll_wait.
+ *
+ * Results:
+ *	Returns -1 if epoll_wait 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), epoll_wait(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 epoll_event *events,
+    size_t numEvents,
+    struct timeval *timePtr)
+{
+    int numFound;
+    struct timeval tv0, tv1, tv_delta;
+    int timeout;
+
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    /*
+     * If timePtr is NULL, epoll_wait(2) will wait indefinitely. If it
+     * specifies a timeout of {0,0}, epoll_wait(2) will poll. Otherwise,
+     * the timeout will simply be converted to milliseconds.
+     */
+
+    if (!timePtr) {
+	timeout = -1;
+    } else if (!timePtr->tv_sec && !timePtr->tv_usec) {
+	timeout = 0;
+    } else {
+	timeout = (int)timePtr->tv_sec;
+    }
+
+    /*
+     * Call (and possibly block on) epoll_wait(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 epoll_wait(2).
+     */
+
+    gettimeofday(&tv0, NULL);
+    numFound = epoll_wait(tsdPtr->eventsFd, events, (int)numEvents, timeout);
+    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 epoll 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, isNew ?
+	    EPOLL_CTL_ADD : EPOLL_CTL_MOD, isNew);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_DeleteFileHandler --
+ *
+ *	Cancel a previously-arranged callback arrangement for a file on
+ *	the epoll file descriptor 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, EPOLL_CTL_DEL, 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;
+#ifdef HAVE_EVENTFD
+	uint64_t eventFdVal;
+#else
+	char triggerPipeVal;
+#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.
+	 */
+
+	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.
+	 * As epoll(7) does not support regular files, 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 eventfd(2)/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 eventfd(2)/trigger 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 = tsdPtr->readyEvents[numEvent].data.ptr;
+	    filePtr = pedPtr->filePtr;
+	    mask = PlatformEventsTranslate(&tsdPtr->readyEvents[numEvent]);
+#ifdef HAVE_EVENTFD
+	    if (filePtr->fd == tsdPtr->triggerEventFd) {
+		i = read(tsdPtr->triggerEventFd, &eventFdVal, sizeof(eventFdVal));
+		if ((i != sizeof(eventFdVal)) && (errno != EAGAIN)) {
+#else
+	    if (filePtr->fd == tsdPtr->triggerPipe[0]) {
+		i = read(tsdPtr->triggerPipe[0], &triggerPipeVal, sizeof(triggerPipeVal));
+		if ((i != sizeof(triggerPipeVal)) && (errno != EAGAIN)) {
+#endif
+			Tcl_Panic("Tcl_WaitForEvent: "
+				"read from %p->triggerEventFd: %s",
+				(void *)tsdPtr, strerror(errno));
+		} else {
+		    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 /* !HAVE_COREFOUNDATION */
+
+#endif /* NOTIFIER_EPOLL */
+
+/*
+ * Local Variables:
+ * mode: c
+ * c-basic-offset: 4
+ * fill-column: 78
+ * End:
+ */