[libvirt] [PATCH 09/28] Rename event_poll.{c, h} to vireventpoll.{c, h}

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; --- po/POTFILES.in | 2 +- src/Makefile.am | 2 +- src/rpc/virnetservermdns.c | 2 +- src/util/event_poll.c | 761 --------------------------------------------- src/util/event_poll.h | 132 -------- src/util/virevent.c | 2 +- src/util/vireventpoll.c | 761 +++++++++++++++++++++++++++++++++++++++++++++ src/util/vireventpoll.h | 132 ++++++++ tests/eventtest.c | 2 +- tools/virsh.c | 1 - 10 files changed, 898 insertions(+), 899 deletions(-) delete mode 100644 src/util/event_poll.c delete mode 100644 src/util/event_poll.h create mode 100644 src/util/vireventpoll.c create mode 100644 src/util/vireventpoll.h diff --git a/po/POTFILES.in b/po/POTFILES.in index 3214ebe..818bb4e 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -137,7 +137,6 @@ src/storage/storage_driver.c src/test/test_driver.c src/uml/uml_conf.c src/uml/uml_driver.c -src/util/event_poll.c src/util/hooks.c src/util/hostusb.c src/util/iohelper.c @@ -158,6 +157,7 @@ src/util/vircommand.c src/util/virconf.c src/util/virdbus.c src/util/virdnsmasq.c +src/util/vireventpoll.c src/util/virfile.c src/util/virhash.c src/util/virinitctl.c diff --git a/src/Makefile.am b/src/Makefile.am index 5c0d668..f803de0 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -53,7 +53,6 @@ augeastest_DATA = # These files are not related to driver APIs. Simply generic # helper APIs for various purposes UTIL_SOURCES = \ - util/event_poll.c util/event_poll.h \ util/hooks.c util/hooks.h \ util/iptables.c util/iptables.h \ util/json.c util/json.h \ @@ -83,6 +82,7 @@ UTIL_SOURCES = \ util/virdnsmasq.c util/virdnsmasq.h \ util/virebtables.c util/virebtables.h \ util/virevent.c util/virevent.h \ + util/vireventpoll.c util/vireventpoll.h \ util/virfile.c util/virfile.h \ util/virnodesuspend.c util/virnodesuspend.h \ util/virobject.c util/virobject.h \ diff --git a/src/rpc/virnetservermdns.c b/src/rpc/virnetservermdns.c index 0ddb9d8..166b4eb 100644 --- a/src/rpc/virnetservermdns.c +++ b/src/rpc/virnetservermdns.c @@ -41,7 +41,7 @@ #endif #include "virnetservermdns.h" -#include "event_poll.h" +#include "vireventpoll.h" #include "memory.h" #include "virterror_internal.h" #include "logging.h" diff --git a/src/util/event_poll.c b/src/util/event_poll.c deleted file mode 100644 index 7a83a37..0000000 --- a/src/util/event_poll.c +++ /dev/null @@ -1,761 +0,0 @@ -/* - * event.c: event loop for monitoring file handles - * - * Copyright (C) 2007, 2010-2012 Red Hat, Inc. - * Copyright (C) 2007 Daniel P. Berrange - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library. If not, see - * <http://www.gnu.org/licenses/>;. - * - * Author: Daniel P. Berrange <berrange(a)redhat.com&gt; - */ - -#include <config.h> - -#include <stdlib.h> -#include <string.h> -#include <poll.h> -#include <sys/time.h> -#include <errno.h> -#include <unistd.h> -#include <fcntl.h> - -#include "threads.h" -#include "logging.h" -#include "event_poll.h" -#include "memory.h" -#include "util.h" -#include "virfile.h" -#include "virterror_internal.h" -#include "virtime.h" - -#define EVENT_DEBUG(fmt, ...) VIR_DEBUG(fmt, __VA_ARGS__) - -#define VIR_FROM_THIS VIR_FROM_EVENT - -static int virEventPollInterruptLocked(void); - -/* State for a single file handle being monitored */ -struct virEventPollHandle { - int watch; - int fd; - int events; - virEventHandleCallback cb; - virFreeCallback ff; - void *opaque; - int deleted; -}; - -/* State for a single timer being generated */ -struct virEventPollTimeout { - int timer; - int frequency; - unsigned long long expiresAt; - virEventTimeoutCallback cb; - virFreeCallback ff; - void *opaque; - int deleted; -}; - -/* Allocate extra slots for virEventPollHandle/virEventPollTimeout - records in this multiple */ -#define EVENT_ALLOC_EXTENT 10 - -/* State for the main event loop */ -struct virEventPollLoop { - virMutex lock; - int running; - virThread leader; - int wakeupfd[2]; - size_t handlesCount; - size_t handlesAlloc; - struct virEventPollHandle *handles; - size_t timeoutsCount; - size_t timeoutsAlloc; - struct virEventPollTimeout *timeouts; -}; - -/* Only have one event loop */ -static struct virEventPollLoop eventLoop; - -/* Unique ID for the next FD watch to be registered */ -static int nextWatch = 1; - -/* Unique ID for the next timer to be registered */ -static int nextTimer = 1; - -/* - * Register a callback for monitoring file handle events. - * NB, it *must* be safe to call this from within a callback - * For this reason we only ever append to existing list. - */ -int virEventPollAddHandle(int fd, int events, - virEventHandleCallback cb, - void *opaque, - virFreeCallback ff) { - int watch; - virMutexLock(&eventLoop.lock); - if (eventLoop.handlesCount == eventLoop.handlesAlloc) { - EVENT_DEBUG("Used %zu handle slots, adding at least %d more", - eventLoop.handlesAlloc, EVENT_ALLOC_EXTENT); - if (VIR_RESIZE_N(eventLoop.handles, eventLoop.handlesAlloc, - eventLoop.handlesCount, EVENT_ALLOC_EXTENT) < 0) { - virMutexUnlock(&eventLoop.lock); - return -1; - } - } - - watch = nextWatch++; - - eventLoop.handles[eventLoop.handlesCount].watch = watch; - eventLoop.handles[eventLoop.handlesCount].fd = fd; - eventLoop.handles[eventLoop.handlesCount].events = - virEventPollToNativeEvents(events); - eventLoop.handles[eventLoop.handlesCount].cb = cb; - eventLoop.handles[eventLoop.handlesCount].ff = ff; - eventLoop.handles[eventLoop.handlesCount].opaque = opaque; - eventLoop.handles[eventLoop.handlesCount].deleted = 0; - - eventLoop.handlesCount++; - - virEventPollInterruptLocked(); - - PROBE(EVENT_POLL_ADD_HANDLE, - "watch=%d fd=%d events=%d cb=%p opaque=%p ff=%p", - watch, fd, events, cb, opaque, ff); - virMutexUnlock(&eventLoop.lock); - - return watch; -} - -void virEventPollUpdateHandle(int watch, int events) { - int i; - bool found = false; - PROBE(EVENT_POLL_UPDATE_HANDLE, - "watch=%d events=%d", - watch, events); - - if (watch <= 0) { - VIR_WARN("Ignoring invalid update watch %d", watch); - return; - } - - virMutexLock(&eventLoop.lock); - for (i = 0 ; i < eventLoop.handlesCount ; i++) { - if (eventLoop.handles[i].watch == watch) { - eventLoop.handles[i].events = - virEventPollToNativeEvents(events); - virEventPollInterruptLocked(); - found = true; - break; - } - } - virMutexUnlock(&eventLoop.lock); - - if (!found) - VIR_WARN("Got update for non-existent handle watch %d", watch); -} - -/* - * Unregister a callback from a file handle - * NB, it *must* be safe to call this from within a callback - * For this reason we only ever set a flag in the existing list. - * Actual deletion will be done out-of-band - */ -int virEventPollRemoveHandle(int watch) { - int i; - PROBE(EVENT_POLL_REMOVE_HANDLE, - "watch=%d", - watch); - - if (watch <= 0) { - VIR_WARN("Ignoring invalid remove watch %d", watch); - return -1; - } - - virMutexLock(&eventLoop.lock); - for (i = 0 ; i < eventLoop.handlesCount ; i++) { - if (eventLoop.handles[i].deleted) - continue; - - if (eventLoop.handles[i].watch == watch) { - EVENT_DEBUG("mark delete %d %d", i, eventLoop.handles[i].fd); - eventLoop.handles[i].deleted = 1; - virEventPollInterruptLocked(); - virMutexUnlock(&eventLoop.lock); - return 0; - } - } - virMutexUnlock(&eventLoop.lock); - return -1; -} - - -/* - * Register a callback for a timer event - * NB, it *must* be safe to call this from within a callback - * For this reason we only ever append to existing list. - */ -int virEventPollAddTimeout(int frequency, - virEventTimeoutCallback cb, - void *opaque, - virFreeCallback ff) -{ - unsigned long long now; - int ret; - - if (virTimeMillisNow(&now) < 0) { - return -1; - } - - virMutexLock(&eventLoop.lock); - if (eventLoop.timeoutsCount == eventLoop.timeoutsAlloc) { - EVENT_DEBUG("Used %zu timeout slots, adding at least %d more", - eventLoop.timeoutsAlloc, EVENT_ALLOC_EXTENT); - if (VIR_RESIZE_N(eventLoop.timeouts, eventLoop.timeoutsAlloc, - eventLoop.timeoutsCount, EVENT_ALLOC_EXTENT) < 0) { - virMutexUnlock(&eventLoop.lock); - return -1; - } - } - - eventLoop.timeouts[eventLoop.timeoutsCount].timer = nextTimer++; - eventLoop.timeouts[eventLoop.timeoutsCount].frequency = frequency; - eventLoop.timeouts[eventLoop.timeoutsCount].cb = cb; - eventLoop.timeouts[eventLoop.timeoutsCount].ff = ff; - eventLoop.timeouts[eventLoop.timeoutsCount].opaque = opaque; - eventLoop.timeouts[eventLoop.timeoutsCount].deleted = 0; - eventLoop.timeouts[eventLoop.timeoutsCount].expiresAt = - frequency >= 0 ? frequency + now : 0; - - eventLoop.timeoutsCount++; - ret = nextTimer-1; - virEventPollInterruptLocked(); - - PROBE(EVENT_POLL_ADD_TIMEOUT, - "timer=%d frequency=%d cb=%p opaque=%p ff=%p", - ret, frequency, cb, opaque, ff); - virMutexUnlock(&eventLoop.lock); - return ret; -} - -void virEventPollUpdateTimeout(int timer, int frequency) -{ - unsigned long long now; - int i; - bool found = false; - PROBE(EVENT_POLL_UPDATE_TIMEOUT, - "timer=%d frequency=%d", - timer, frequency); - - if (timer <= 0) { - VIR_WARN("Ignoring invalid update timer %d", timer); - return; - } - - if (virTimeMillisNow(&now) < 0) { - return; - } - - virMutexLock(&eventLoop.lock); - for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { - if (eventLoop.timeouts[i].timer == timer) { - eventLoop.timeouts[i].frequency = frequency; - eventLoop.timeouts[i].expiresAt = - frequency >= 0 ? frequency + now : 0; - VIR_DEBUG("Set timer freq=%d expires=%llu", frequency, - eventLoop.timeouts[i].expiresAt); - virEventPollInterruptLocked(); - found = true; - break; - } - } - virMutexUnlock(&eventLoop.lock); - - if (!found) - VIR_WARN("Got update for non-existent timer %d", timer); -} - -/* - * Unregister a callback for a timer - * NB, it *must* be safe to call this from within a callback - * For this reason we only ever set a flag in the existing list. - * Actual deletion will be done out-of-band - */ -int virEventPollRemoveTimeout(int timer) { - int i; - PROBE(EVENT_POLL_REMOVE_TIMEOUT, - "timer=%d", - timer); - - if (timer <= 0) { - VIR_WARN("Ignoring invalid remove timer %d", timer); - return -1; - } - - virMutexLock(&eventLoop.lock); - for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { - if (eventLoop.timeouts[i].deleted) - continue; - - if (eventLoop.timeouts[i].timer == timer) { - eventLoop.timeouts[i].deleted = 1; - virEventPollInterruptLocked(); - virMutexUnlock(&eventLoop.lock); - return 0; - } - } - virMutexUnlock(&eventLoop.lock); - return -1; -} - -/* Iterates over all registered timeouts and determine which - * will be the first to expire. - * @timeout: filled with expiry time of soonest timer, or -1 if - * no timeout is pending - * returns: 0 on success, -1 on error - */ -static int virEventPollCalculateTimeout(int *timeout) { - unsigned long long then = 0; - int i; - EVENT_DEBUG("Calculate expiry of %zu timers", eventLoop.timeoutsCount); - /* Figure out if we need a timeout */ - for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { - if (eventLoop.timeouts[i].deleted) - continue; - if (eventLoop.timeouts[i].frequency < 0) - continue; - - EVENT_DEBUG("Got a timeout scheduled for %llu", eventLoop.timeouts[i].expiresAt); - if (then == 0 || - eventLoop.timeouts[i].expiresAt < then) - then = eventLoop.timeouts[i].expiresAt; - } - - /* Calculate how long we should wait for a timeout if needed */ - if (then > 0) { - unsigned long long now; - - if (virTimeMillisNow(&now) < 0) - return -1; - - EVENT_DEBUG("Schedule timeout then=%llu now=%llu", then, now); - *timeout = then - now; - if (*timeout < 0) - *timeout = 0; - } else { - *timeout = -1; - } - - EVENT_DEBUG("Timeout at %llu due in %d ms", then, *timeout); - - return 0; -} - -/* - * Allocate a pollfd array containing data for all registered - * file handles. The caller must free the returned data struct - * returns: the pollfd array, or NULL on error - */ -static struct pollfd *virEventPollMakePollFDs(int *nfds) { - struct pollfd *fds; - int i; - - *nfds = 0; - for (i = 0 ; i < eventLoop.handlesCount ; i++) { - if (eventLoop.handles[i].events && !eventLoop.handles[i].deleted) - (*nfds)++; - } - - /* Setup the poll file handle data structs */ - if (VIR_ALLOC_N(fds, *nfds) < 0) { - virReportOOMError(); - return NULL; - } - - *nfds = 0; - for (i = 0 ; i < eventLoop.handlesCount ; i++) { - EVENT_DEBUG("Prepare n=%d w=%d, f=%d e=%d d=%d", i, - eventLoop.handles[i].watch, - eventLoop.handles[i].fd, - eventLoop.handles[i].events, - eventLoop.handles[i].deleted); - if (!eventLoop.handles[i].events || eventLoop.handles[i].deleted) - continue; - fds[*nfds].fd = eventLoop.handles[i].fd; - fds[*nfds].events = eventLoop.handles[i].events; - fds[*nfds].revents = 0; - (*nfds)++; - //EVENT_DEBUG("Wait for %d %d", eventLoop.handles[i].fd, eventLoop.handles[i].events); - } - - return fds; -} - - -/* - * Iterate over all timers and determine if any have expired. - * Invoke the user supplied callback for each timer whose - * expiry time is met, and schedule the next timeout. Does - * not try to 'catch up' on time if the actual expiry time - * was later than the requested time. - * - * This method must cope with new timers being registered - * by a callback, and must skip any timers marked as deleted. - * - * Returns 0 upon success, -1 if an error occurred - */ -static int virEventPollDispatchTimeouts(void) -{ - unsigned long long now; - int i; - /* Save this now - it may be changed during dispatch */ - int ntimeouts = eventLoop.timeoutsCount; - VIR_DEBUG("Dispatch %d", ntimeouts); - - if (virTimeMillisNow(&now) < 0) - return -1; - - for (i = 0 ; i < ntimeouts ; i++) { - if (eventLoop.timeouts[i].deleted || eventLoop.timeouts[i].frequency < 0) - continue; - - /* Add 20ms fuzz so we don't pointlessly spin doing - * <10ms sleeps, particularly on kernels with low HZ - * it is fine that a timer expires 20ms earlier than - * requested - */ - if (eventLoop.timeouts[i].expiresAt <= (now+20)) { - virEventTimeoutCallback cb = eventLoop.timeouts[i].cb; - int timer = eventLoop.timeouts[i].timer; - void *opaque = eventLoop.timeouts[i].opaque; - eventLoop.timeouts[i].expiresAt = - now + eventLoop.timeouts[i].frequency; - - PROBE(EVENT_POLL_DISPATCH_TIMEOUT, - "timer=%d", - timer); - virMutexUnlock(&eventLoop.lock); - (cb)(timer, opaque); - virMutexLock(&eventLoop.lock); - } - } - return 0; -} - - -/* Iterate over all file handles and dispatch any which - * have pending events listed in the poll() data. Invoke - * the user supplied callback for each handle which has - * pending events - * - * This method must cope with new handles being registered - * by a callback, and must skip any handles marked as deleted. - * - * Returns 0 upon success, -1 if an error occurred - */ -static int virEventPollDispatchHandles(int nfds, struct pollfd *fds) { - int i, n; - VIR_DEBUG("Dispatch %d", nfds); - - /* NB, use nfds not eventLoop.handlesCount, because new - * fds might be added on end of list, and they're not - * in the fds array we've got */ - for (i = 0, n = 0 ; n < nfds && i < eventLoop.handlesCount ; n++) { - while ((eventLoop.handles[i].fd != fds[n].fd || - eventLoop.handles[i].events == 0) && - i < eventLoop.handlesCount) { - i++; - } - if (i == eventLoop.handlesCount) - break; - - VIR_DEBUG("i=%d w=%d", i, eventLoop.handles[i].watch); - if (eventLoop.handles[i].deleted) { - EVENT_DEBUG("Skip deleted n=%d w=%d f=%d", i, - eventLoop.handles[i].watch, eventLoop.handles[i].fd); - continue; - } - - if (fds[n].revents) { - virEventHandleCallback cb = eventLoop.handles[i].cb; - int watch = eventLoop.handles[i].watch; - void *opaque = eventLoop.handles[i].opaque; - int hEvents = virEventPollFromNativeEvents(fds[n].revents); - PROBE(EVENT_POLL_DISPATCH_HANDLE, - "watch=%d events=%d", - watch, hEvents); - virMutexUnlock(&eventLoop.lock); - (cb)(watch, fds[n].fd, hEvents, opaque); - virMutexLock(&eventLoop.lock); - } - } - - return 0; -} - - -/* Used post dispatch to actually remove any timers that - * were previously marked as deleted. This asynchronous - * cleanup is needed to make dispatch re-entrant safe. - */ -static void virEventPollCleanupTimeouts(void) { - int i; - size_t gap; - VIR_DEBUG("Cleanup %zu", eventLoop.timeoutsCount); - - /* Remove deleted entries, shuffling down remaining - * entries as needed to form contiguous series - */ - for (i = 0 ; i < eventLoop.timeoutsCount ;) { - if (!eventLoop.timeouts[i].deleted) { - i++; - continue; - } - - PROBE(EVENT_POLL_PURGE_TIMEOUT, - "timer=%d", - eventLoop.timeouts[i].timer); - if (eventLoop.timeouts[i].ff) { - virFreeCallback ff = eventLoop.timeouts[i].ff; - void *opaque = eventLoop.timeouts[i].opaque; - virMutexUnlock(&eventLoop.lock); - ff(opaque); - virMutexLock(&eventLoop.lock); - } - - if ((i+1) < eventLoop.timeoutsCount) { - memmove(eventLoop.timeouts+i, - eventLoop.timeouts+i+1, - sizeof(struct virEventPollTimeout)*(eventLoop.timeoutsCount - -(i+1))); - } - eventLoop.timeoutsCount--; - } - - /* Release some memory if we've got a big chunk free */ - gap = eventLoop.timeoutsAlloc - eventLoop.timeoutsCount; - if (eventLoop.timeoutsCount == 0 || - (gap > eventLoop.timeoutsCount && gap > EVENT_ALLOC_EXTENT)) { - EVENT_DEBUG("Found %zu out of %zu timeout slots used, releasing %zu", - eventLoop.timeoutsCount, eventLoop.timeoutsAlloc, gap); - VIR_SHRINK_N(eventLoop.timeouts, eventLoop.timeoutsAlloc, gap); - } -} - -/* Used post dispatch to actually remove any handles that - * were previously marked as deleted. This asynchronous - * cleanup is needed to make dispatch re-entrant safe. - */ -static void virEventPollCleanupHandles(void) { - int i; - size_t gap; - VIR_DEBUG("Cleanup %zu", eventLoop.handlesCount); - - /* Remove deleted entries, shuffling down remaining - * entries as needed to form contiguous series - */ - for (i = 0 ; i < eventLoop.handlesCount ;) { - if (!eventLoop.handles[i].deleted) { - i++; - continue; - } - - PROBE(EVENT_POLL_PURGE_HANDLE, - "watch=%d", - eventLoop.handles[i].watch); - if (eventLoop.handles[i].ff) { - virFreeCallback ff = eventLoop.handles[i].ff; - void *opaque = eventLoop.handles[i].opaque; - virMutexUnlock(&eventLoop.lock); - ff(opaque); - virMutexLock(&eventLoop.lock); - } - - if ((i+1) < eventLoop.handlesCount) { - memmove(eventLoop.handles+i, - eventLoop.handles+i+1, - sizeof(struct virEventPollHandle)*(eventLoop.handlesCount - -(i+1))); - } - eventLoop.handlesCount--; - } - - /* Release some memory if we've got a big chunk free */ - gap = eventLoop.handlesAlloc - eventLoop.handlesCount; - if (eventLoop.handlesCount == 0 || - (gap > eventLoop.handlesCount && gap > EVENT_ALLOC_EXTENT)) { - EVENT_DEBUG("Found %zu out of %zu handles slots used, releasing %zu", - eventLoop.handlesCount, eventLoop.handlesAlloc, gap); - VIR_SHRINK_N(eventLoop.handles, eventLoop.handlesAlloc, gap); - } -} - -/* - * Run a single iteration of the event loop, blocking until - * at least one file handle has an event, or a timer expires - */ -int virEventPollRunOnce(void) { - struct pollfd *fds = NULL; - int ret, timeout, nfds; - - virMutexLock(&eventLoop.lock); - eventLoop.running = 1; - virThreadSelf(&eventLoop.leader); - - virEventPollCleanupTimeouts(); - virEventPollCleanupHandles(); - - if (!(fds = virEventPollMakePollFDs(&nfds)) || - virEventPollCalculateTimeout(&timeout) < 0) - goto error; - - virMutexUnlock(&eventLoop.lock); - - retry: - PROBE(EVENT_POLL_RUN, - "nhandles=%d timeout=%d", - nfds, timeout); - ret = poll(fds, nfds, timeout); - if (ret < 0) { - EVENT_DEBUG("Poll got error event %d", errno); - if (errno == EINTR || errno == EAGAIN) { - goto retry; - } - virReportSystemError(errno, "%s", - _("Unable to poll on file handles")); - goto error_unlocked; - } - EVENT_DEBUG("Poll got %d event(s)", ret); - - virMutexLock(&eventLoop.lock); - if (virEventPollDispatchTimeouts() < 0) - goto error; - - if (ret > 0 && - virEventPollDispatchHandles(nfds, fds) < 0) - goto error; - - virEventPollCleanupTimeouts(); - virEventPollCleanupHandles(); - - eventLoop.running = 0; - virMutexUnlock(&eventLoop.lock); - VIR_FREE(fds); - return 0; - -error: - virMutexUnlock(&eventLoop.lock); -error_unlocked: - VIR_FREE(fds); - return -1; -} - - -static void virEventPollHandleWakeup(int watch ATTRIBUTE_UNUSED, - int fd, - int events ATTRIBUTE_UNUSED, - void *opaque ATTRIBUTE_UNUSED) -{ - char c; - virMutexLock(&eventLoop.lock); - ignore_value(saferead(fd, &c, sizeof(c))); - virMutexUnlock(&eventLoop.lock); -} - -int virEventPollInit(void) -{ - if (virMutexInit(&eventLoop.lock) < 0) { - virReportSystemError(errno, "%s", - _("Unable to initialize mutex")); - return -1; - } - - if (pipe2(eventLoop.wakeupfd, O_CLOEXEC | O_NONBLOCK) < 0) { - virReportSystemError(errno, "%s", - _("Unable to setup wakeup pipe")); - return -1; - } - - if (virEventPollAddHandle(eventLoop.wakeupfd[0], - VIR_EVENT_HANDLE_READABLE, - virEventPollHandleWakeup, NULL, NULL) < 0) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("Unable to add handle %d to event loop"), - eventLoop.wakeupfd[0]); - VIR_FORCE_CLOSE(eventLoop.wakeupfd[0]); - VIR_FORCE_CLOSE(eventLoop.wakeupfd[1]); - return -1; - } - - return 0; -} - -static int virEventPollInterruptLocked(void) -{ - char c = '\0'; - - if (!eventLoop.running || - virThreadIsSelf(&eventLoop.leader)) { - VIR_DEBUG("Skip interrupt, %d %d", eventLoop.running, - virThreadID(&eventLoop.leader)); - return 0; - } - - VIR_DEBUG("Interrupting"); - if (safewrite(eventLoop.wakeupfd[1], &c, sizeof(c)) != sizeof(c)) - return -1; - return 0; -} - -int virEventPollInterrupt(void) -{ - int ret; - virMutexLock(&eventLoop.lock); - ret = virEventPollInterruptLocked(); - virMutexUnlock(&eventLoop.lock); - return ret; -} - -int -virEventPollToNativeEvents(int events) -{ - int ret = 0; - if (events & VIR_EVENT_HANDLE_READABLE) - ret |= POLLIN; - if (events & VIR_EVENT_HANDLE_WRITABLE) - ret |= POLLOUT; - if (events & VIR_EVENT_HANDLE_ERROR) - ret |= POLLERR; - if (events & VIR_EVENT_HANDLE_HANGUP) - ret |= POLLHUP; - return ret; -} - -int -virEventPollFromNativeEvents(int events) -{ - int ret = 0; - if (events & POLLIN) - ret |= VIR_EVENT_HANDLE_READABLE; - if (events & POLLOUT) - ret |= VIR_EVENT_HANDLE_WRITABLE; - if (events & POLLERR) - ret |= VIR_EVENT_HANDLE_ERROR; - if (events & POLLNVAL) /* Treat NVAL as error, since libvirt doesn't distinguish */ - ret |= VIR_EVENT_HANDLE_ERROR; - if (events & POLLHUP) - ret |= VIR_EVENT_HANDLE_HANGUP; - return ret; -} diff --git a/src/util/event_poll.h b/src/util/event_poll.h deleted file mode 100644 index 64b2e96..0000000 --- a/src/util/event_poll.h +++ /dev/null @@ -1,132 +0,0 @@ -/* - * event.h: event loop for monitoring file handles - * - * Copyright (C) 2007 Daniel P. Berrange - * Copyright (C) 2007 Red Hat, Inc. - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library. If not, see - * <http://www.gnu.org/licenses/>;. - * - * Author: Daniel P. Berrange <berrange(a)redhat.com&gt; - */ - -#ifndef __VIR_EVENT_POLL_H__ -# define __VIR_EVENT_POLL_H__ - -# include "internal.h" - -/** - * virEventPollAddHandle: register a callback for monitoring file handle events - * - * @fd: file handle to monitor for events - * @events: bitset of events to watch from POLLnnn constants - * @cb: callback to invoke when an event occurs - * @opaque: user data to pass to callback - * - * returns -1 if the file handle cannot be registered, 0 upon success - */ -int virEventPollAddHandle(int fd, int events, - virEventHandleCallback cb, - void *opaque, - virFreeCallback ff); - -/** - * virEventPollUpdateHandle: change event set for a monitored file handle - * - * @watch: watch whose handle to update - * @events: bitset of events to watch from POLLnnn constants - * - * Will not fail if fd exists - */ -void virEventPollUpdateHandle(int watch, int events); - -/** - * virEventPollRemoveHandle: unregister a callback from a file handle - * - * @watch: watch whose handle to remove - * - * returns -1 if the file handle was not registered, 0 upon success - */ -int virEventPollRemoveHandle(int watch); - -/** - * virEventPollAddTimeout: register a callback for a timer event - * - * @frequency: time between events in milliseconds - * @cb: callback to invoke when an event occurs - * @opaque: user data to pass to callback - * - * Setting frequency to -1 will disable the timer. Setting the frequency - * to zero will cause it to fire on every event loop iteration. - * - * returns -1 if the file handle cannot be registered, a positive - * integer timer id upon success - */ -int virEventPollAddTimeout(int frequency, - virEventTimeoutCallback cb, - void *opaque, - virFreeCallback ff); - -/** - * virEventPollUpdateTimeout: change frequency for a timer - * - * @timer: timer id to change - * @frequency: time between events in milliseconds - * - * Setting frequency to -1 will disable the timer. Setting the frequency - * to zero will cause it to fire on every event loop iteration. - * - * Will not fail if timer exists - */ -void virEventPollUpdateTimeout(int timer, int frequency); - -/** - * virEventPollRemoveTimeout: unregister a callback for a timer - * - * @timer: the timer id to remove - * - * returns -1 if the timer was not registered, 0 upon success - */ -int virEventPollRemoveTimeout(int timer); - -/** - * virEventPollInit: Initialize the event loop - * - * returns -1 if initialization failed - */ -int virEventPollInit(void); - -/** - * virEventPollRunOnce: run a single iteration of the event loop. - * - * Blocks the caller until at least one file handle has an - * event or the first timer expires. - * - * returns -1 if the event monitoring failed - */ -int virEventPollRunOnce(void); - -int virEventPollFromNativeEvents(int events); -int virEventPollToNativeEvents(int events); - - -/** - * virEventPollInterrupt: wakeup any thread waiting in poll() - * - * return -1 if wakup failed - */ -int virEventPollInterrupt(void); - - -#endif /* __VIRTD_EVENT_H__ */ diff --git a/src/util/virevent.c b/src/util/virevent.c index 08b7006..7d11f85 100644 --- a/src/util/virevent.c +++ b/src/util/virevent.c @@ -24,7 +24,7 @@ #include <config.h> #include "virevent.h" -#include "event_poll.h" +#include "vireventpoll.h" #include "logging.h" #include "virterror_internal.h" diff --git a/src/util/vireventpoll.c b/src/util/vireventpoll.c new file mode 100644 index 0000000..9fd196d --- /dev/null +++ b/src/util/vireventpoll.c @@ -0,0 +1,761 @@ +/* + * event.c: event loop for monitoring file handles + * + * Copyright (C) 2007, 2010-2012 Red Hat, Inc. + * Copyright (C) 2007 Daniel P. Berrange + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>;. + * + * Author: Daniel P. Berrange <berrange(a)redhat.com&gt; + */ + +#include <config.h> + +#include <stdlib.h> +#include <string.h> +#include <poll.h> +#include <sys/time.h> +#include <errno.h> +#include <unistd.h> +#include <fcntl.h> + +#include "threads.h" +#include "logging.h" +#include "vireventpoll.h" +#include "memory.h" +#include "util.h" +#include "virfile.h" +#include "virterror_internal.h" +#include "virtime.h" + +#define EVENT_DEBUG(fmt, ...) VIR_DEBUG(fmt, __VA_ARGS__) + +#define VIR_FROM_THIS VIR_FROM_EVENT + +static int virEventPollInterruptLocked(void); + +/* State for a single file handle being monitored */ +struct virEventPollHandle { + int watch; + int fd; + int events; + virEventHandleCallback cb; + virFreeCallback ff; + void *opaque; + int deleted; +}; + +/* State for a single timer being generated */ +struct virEventPollTimeout { + int timer; + int frequency; + unsigned long long expiresAt; + virEventTimeoutCallback cb; + virFreeCallback ff; + void *opaque; + int deleted; +}; + +/* Allocate extra slots for virEventPollHandle/virEventPollTimeout + records in this multiple */ +#define EVENT_ALLOC_EXTENT 10 + +/* State for the main event loop */ +struct virEventPollLoop { + virMutex lock; + int running; + virThread leader; + int wakeupfd[2]; + size_t handlesCount; + size_t handlesAlloc; + struct virEventPollHandle *handles; + size_t timeoutsCount; + size_t timeoutsAlloc; + struct virEventPollTimeout *timeouts; +}; + +/* Only have one event loop */ +static struct virEventPollLoop eventLoop; + +/* Unique ID for the next FD watch to be registered */ +static int nextWatch = 1; + +/* Unique ID for the next timer to be registered */ +static int nextTimer = 1; + +/* + * Register a callback for monitoring file handle events. + * NB, it *must* be safe to call this from within a callback + * For this reason we only ever append to existing list. + */ +int virEventPollAddHandle(int fd, int events, + virEventHandleCallback cb, + void *opaque, + virFreeCallback ff) { + int watch; + virMutexLock(&eventLoop.lock); + if (eventLoop.handlesCount == eventLoop.handlesAlloc) { + EVENT_DEBUG("Used %zu handle slots, adding at least %d more", + eventLoop.handlesAlloc, EVENT_ALLOC_EXTENT); + if (VIR_RESIZE_N(eventLoop.handles, eventLoop.handlesAlloc, + eventLoop.handlesCount, EVENT_ALLOC_EXTENT) < 0) { + virMutexUnlock(&eventLoop.lock); + return -1; + } + } + + watch = nextWatch++; + + eventLoop.handles[eventLoop.handlesCount].watch = watch; + eventLoop.handles[eventLoop.handlesCount].fd = fd; + eventLoop.handles[eventLoop.handlesCount].events = + virEventPollToNativeEvents(events); + eventLoop.handles[eventLoop.handlesCount].cb = cb; + eventLoop.handles[eventLoop.handlesCount].ff = ff; + eventLoop.handles[eventLoop.handlesCount].opaque = opaque; + eventLoop.handles[eventLoop.handlesCount].deleted = 0; + + eventLoop.handlesCount++; + + virEventPollInterruptLocked(); + + PROBE(EVENT_POLL_ADD_HANDLE, + "watch=%d fd=%d events=%d cb=%p opaque=%p ff=%p", + watch, fd, events, cb, opaque, ff); + virMutexUnlock(&eventLoop.lock); + + return watch; +} + +void virEventPollUpdateHandle(int watch, int events) { + int i; + bool found = false; + PROBE(EVENT_POLL_UPDATE_HANDLE, + "watch=%d events=%d", + watch, events); + + if (watch <= 0) { + VIR_WARN("Ignoring invalid update watch %d", watch); + return; + } + + virMutexLock(&eventLoop.lock); + for (i = 0 ; i < eventLoop.handlesCount ; i++) { + if (eventLoop.handles[i].watch == watch) { + eventLoop.handles[i].events = + virEventPollToNativeEvents(events); + virEventPollInterruptLocked(); + found = true; + break; + } + } + virMutexUnlock(&eventLoop.lock); + + if (!found) + VIR_WARN("Got update for non-existent handle watch %d", watch); +} + +/* + * Unregister a callback from a file handle + * NB, it *must* be safe to call this from within a callback + * For this reason we only ever set a flag in the existing list. + * Actual deletion will be done out-of-band + */ +int virEventPollRemoveHandle(int watch) { + int i; + PROBE(EVENT_POLL_REMOVE_HANDLE, + "watch=%d", + watch); + + if (watch <= 0) { + VIR_WARN("Ignoring invalid remove watch %d", watch); + return -1; + } + + virMutexLock(&eventLoop.lock); + for (i = 0 ; i < eventLoop.handlesCount ; i++) { + if (eventLoop.handles[i].deleted) + continue; + + if (eventLoop.handles[i].watch == watch) { + EVENT_DEBUG("mark delete %d %d", i, eventLoop.handles[i].fd); + eventLoop.handles[i].deleted = 1; + virEventPollInterruptLocked(); + virMutexUnlock(&eventLoop.lock); + return 0; + } + } + virMutexUnlock(&eventLoop.lock); + return -1; +} + + +/* + * Register a callback for a timer event + * NB, it *must* be safe to call this from within a callback + * For this reason we only ever append to existing list. + */ +int virEventPollAddTimeout(int frequency, + virEventTimeoutCallback cb, + void *opaque, + virFreeCallback ff) +{ + unsigned long long now; + int ret; + + if (virTimeMillisNow(&now) < 0) { + return -1; + } + + virMutexLock(&eventLoop.lock); + if (eventLoop.timeoutsCount == eventLoop.timeoutsAlloc) { + EVENT_DEBUG("Used %zu timeout slots, adding at least %d more", + eventLoop.timeoutsAlloc, EVENT_ALLOC_EXTENT); + if (VIR_RESIZE_N(eventLoop.timeouts, eventLoop.timeoutsAlloc, + eventLoop.timeoutsCount, EVENT_ALLOC_EXTENT) < 0) { + virMutexUnlock(&eventLoop.lock); + return -1; + } + } + + eventLoop.timeouts[eventLoop.timeoutsCount].timer = nextTimer++; + eventLoop.timeouts[eventLoop.timeoutsCount].frequency = frequency; + eventLoop.timeouts[eventLoop.timeoutsCount].cb = cb; + eventLoop.timeouts[eventLoop.timeoutsCount].ff = ff; + eventLoop.timeouts[eventLoop.timeoutsCount].opaque = opaque; + eventLoop.timeouts[eventLoop.timeoutsCount].deleted = 0; + eventLoop.timeouts[eventLoop.timeoutsCount].expiresAt = + frequency >= 0 ? frequency + now : 0; + + eventLoop.timeoutsCount++; + ret = nextTimer-1; + virEventPollInterruptLocked(); + + PROBE(EVENT_POLL_ADD_TIMEOUT, + "timer=%d frequency=%d cb=%p opaque=%p ff=%p", + ret, frequency, cb, opaque, ff); + virMutexUnlock(&eventLoop.lock); + return ret; +} + +void virEventPollUpdateTimeout(int timer, int frequency) +{ + unsigned long long now; + int i; + bool found = false; + PROBE(EVENT_POLL_UPDATE_TIMEOUT, + "timer=%d frequency=%d", + timer, frequency); + + if (timer <= 0) { + VIR_WARN("Ignoring invalid update timer %d", timer); + return; + } + + if (virTimeMillisNow(&now) < 0) { + return; + } + + virMutexLock(&eventLoop.lock); + for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { + if (eventLoop.timeouts[i].timer == timer) { + eventLoop.timeouts[i].frequency = frequency; + eventLoop.timeouts[i].expiresAt = + frequency >= 0 ? frequency + now : 0; + VIR_DEBUG("Set timer freq=%d expires=%llu", frequency, + eventLoop.timeouts[i].expiresAt); + virEventPollInterruptLocked(); + found = true; + break; + } + } + virMutexUnlock(&eventLoop.lock); + + if (!found) + VIR_WARN("Got update for non-existent timer %d", timer); +} + +/* + * Unregister a callback for a timer + * NB, it *must* be safe to call this from within a callback + * For this reason we only ever set a flag in the existing list. + * Actual deletion will be done out-of-band + */ +int virEventPollRemoveTimeout(int timer) { + int i; + PROBE(EVENT_POLL_REMOVE_TIMEOUT, + "timer=%d", + timer); + + if (timer <= 0) { + VIR_WARN("Ignoring invalid remove timer %d", timer); + return -1; + } + + virMutexLock(&eventLoop.lock); + for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { + if (eventLoop.timeouts[i].deleted) + continue; + + if (eventLoop.timeouts[i].timer == timer) { + eventLoop.timeouts[i].deleted = 1; + virEventPollInterruptLocked(); + virMutexUnlock(&eventLoop.lock); + return 0; + } + } + virMutexUnlock(&eventLoop.lock); + return -1; +} + +/* Iterates over all registered timeouts and determine which + * will be the first to expire. + * @timeout: filled with expiry time of soonest timer, or -1 if + * no timeout is pending + * returns: 0 on success, -1 on error + */ +static int virEventPollCalculateTimeout(int *timeout) { + unsigned long long then = 0; + int i; + EVENT_DEBUG("Calculate expiry of %zu timers", eventLoop.timeoutsCount); + /* Figure out if we need a timeout */ + for (i = 0 ; i < eventLoop.timeoutsCount ; i++) { + if (eventLoop.timeouts[i].deleted) + continue; + if (eventLoop.timeouts[i].frequency < 0) + continue; + + EVENT_DEBUG("Got a timeout scheduled for %llu", eventLoop.timeouts[i].expiresAt); + if (then == 0 || + eventLoop.timeouts[i].expiresAt < then) + then = eventLoop.timeouts[i].expiresAt; + } + + /* Calculate how long we should wait for a timeout if needed */ + if (then > 0) { + unsigned long long now; + + if (virTimeMillisNow(&now) < 0) + return -1; + + EVENT_DEBUG("Schedule timeout then=%llu now=%llu", then, now); + *timeout = then - now; + if (*timeout < 0) + *timeout = 0; + } else { + *timeout = -1; + } + + EVENT_DEBUG("Timeout at %llu due in %d ms", then, *timeout); + + return 0; +} + +/* + * Allocate a pollfd array containing data for all registered + * file handles. The caller must free the returned data struct + * returns: the pollfd array, or NULL on error + */ +static struct pollfd *virEventPollMakePollFDs(int *nfds) { + struct pollfd *fds; + int i; + + *nfds = 0; + for (i = 0 ; i < eventLoop.handlesCount ; i++) { + if (eventLoop.handles[i].events && !eventLoop.handles[i].deleted) + (*nfds)++; + } + + /* Setup the poll file handle data structs */ + if (VIR_ALLOC_N(fds, *nfds) < 0) { + virReportOOMError(); + return NULL; + } + + *nfds = 0; + for (i = 0 ; i < eventLoop.handlesCount ; i++) { + EVENT_DEBUG("Prepare n=%d w=%d, f=%d e=%d d=%d", i, + eventLoop.handles[i].watch, + eventLoop.handles[i].fd, + eventLoop.handles[i].events, + eventLoop.handles[i].deleted); + if (!eventLoop.handles[i].events || eventLoop.handles[i].deleted) + continue; + fds[*nfds].fd = eventLoop.handles[i].fd; + fds[*nfds].events = eventLoop.handles[i].events; + fds[*nfds].revents = 0; + (*nfds)++; + //EVENT_DEBUG("Wait for %d %d", eventLoop.handles[i].fd, eventLoop.handles[i].events); + } + + return fds; +} + + +/* + * Iterate over all timers and determine if any have expired. + * Invoke the user supplied callback for each timer whose + * expiry time is met, and schedule the next timeout. Does + * not try to 'catch up' on time if the actual expiry time + * was later than the requested time. + * + * This method must cope with new timers being registered + * by a callback, and must skip any timers marked as deleted. + * + * Returns 0 upon success, -1 if an error occurred + */ +static int virEventPollDispatchTimeouts(void) +{ + unsigned long long now; + int i; + /* Save this now - it may be changed during dispatch */ + int ntimeouts = eventLoop.timeoutsCount; + VIR_DEBUG("Dispatch %d", ntimeouts); + + if (virTimeMillisNow(&now) < 0) + return -1; + + for (i = 0 ; i < ntimeouts ; i++) { + if (eventLoop.timeouts[i].deleted || eventLoop.timeouts[i].frequency < 0) + continue; + + /* Add 20ms fuzz so we don't pointlessly spin doing + * <10ms sleeps, particularly on kernels with low HZ + * it is fine that a timer expires 20ms earlier than + * requested + */ + if (eventLoop.timeouts[i].expiresAt <= (now+20)) { + virEventTimeoutCallback cb = eventLoop.timeouts[i].cb; + int timer = eventLoop.timeouts[i].timer; + void *opaque = eventLoop.timeouts[i].opaque; + eventLoop.timeouts[i].expiresAt = + now + eventLoop.timeouts[i].frequency; + + PROBE(EVENT_POLL_DISPATCH_TIMEOUT, + "timer=%d", + timer); + virMutexUnlock(&eventLoop.lock); + (cb)(timer, opaque); + virMutexLock(&eventLoop.lock); + } + } + return 0; +} + + +/* Iterate over all file handles and dispatch any which + * have pending events listed in the poll() data. Invoke + * the user supplied callback for each handle which has + * pending events + * + * This method must cope with new handles being registered + * by a callback, and must skip any handles marked as deleted. + * + * Returns 0 upon success, -1 if an error occurred + */ +static int virEventPollDispatchHandles(int nfds, struct pollfd *fds) { + int i, n; + VIR_DEBUG("Dispatch %d", nfds); + + /* NB, use nfds not eventLoop.handlesCount, because new + * fds might be added on end of list, and they're not + * in the fds array we've got */ + for (i = 0, n = 0 ; n < nfds && i < eventLoop.handlesCount ; n++) { + while ((eventLoop.handles[i].fd != fds[n].fd || + eventLoop.handles[i].events == 0) && + i < eventLoop.handlesCount) { + i++; + } + if (i == eventLoop.handlesCount) + break; + + VIR_DEBUG("i=%d w=%d", i, eventLoop.handles[i].watch); + if (eventLoop.handles[i].deleted) { + EVENT_DEBUG("Skip deleted n=%d w=%d f=%d", i, + eventLoop.handles[i].watch, eventLoop.handles[i].fd); + continue; + } + + if (fds[n].revents) { + virEventHandleCallback cb = eventLoop.handles[i].cb; + int watch = eventLoop.handles[i].watch; + void *opaque = eventLoop.handles[i].opaque; + int hEvents = virEventPollFromNativeEvents(fds[n].revents); + PROBE(EVENT_POLL_DISPATCH_HANDLE, + "watch=%d events=%d", + watch, hEvents); + virMutexUnlock(&eventLoop.lock); + (cb)(watch, fds[n].fd, hEvents, opaque); + virMutexLock(&eventLoop.lock); + } + } + + return 0; +} + + +/* Used post dispatch to actually remove any timers that + * were previously marked as deleted. This asynchronous + * cleanup is needed to make dispatch re-entrant safe. + */ +static void virEventPollCleanupTimeouts(void) { + int i; + size_t gap; + VIR_DEBUG("Cleanup %zu", eventLoop.timeoutsCount); + + /* Remove deleted entries, shuffling down remaining + * entries as needed to form contiguous series + */ + for (i = 0 ; i < eventLoop.timeoutsCount ;) { + if (!eventLoop.timeouts[i].deleted) { + i++; + continue; + } + + PROBE(EVENT_POLL_PURGE_TIMEOUT, + "timer=%d", + eventLoop.timeouts[i].timer); + if (eventLoop.timeouts[i].ff) { + virFreeCallback ff = eventLoop.timeouts[i].ff; + void *opaque = eventLoop.timeouts[i].opaque; + virMutexUnlock(&eventLoop.lock); + ff(opaque); + virMutexLock(&eventLoop.lock); + } + + if ((i+1) < eventLoop.timeoutsCount) { + memmove(eventLoop.timeouts+i, + eventLoop.timeouts+i+1, + sizeof(struct virEventPollTimeout)*(eventLoop.timeoutsCount + -(i+1))); + } + eventLoop.timeoutsCount--; + } + + /* Release some memory if we've got a big chunk free */ + gap = eventLoop.timeoutsAlloc - eventLoop.timeoutsCount; + if (eventLoop.timeoutsCount == 0 || + (gap > eventLoop.timeoutsCount && gap > EVENT_ALLOC_EXTENT)) { + EVENT_DEBUG("Found %zu out of %zu timeout slots used, releasing %zu", + eventLoop.timeoutsCount, eventLoop.timeoutsAlloc, gap); + VIR_SHRINK_N(eventLoop.timeouts, eventLoop.timeoutsAlloc, gap); + } +} + +/* Used post dispatch to actually remove any handles that + * were previously marked as deleted. This asynchronous + * cleanup is needed to make dispatch re-entrant safe. + */ +static void virEventPollCleanupHandles(void) { + int i; + size_t gap; + VIR_DEBUG("Cleanup %zu", eventLoop.handlesCount); + + /* Remove deleted entries, shuffling down remaining + * entries as needed to form contiguous series + */ + for (i = 0 ; i < eventLoop.handlesCount ;) { + if (!eventLoop.handles[i].deleted) { + i++; + continue; + } + + PROBE(EVENT_POLL_PURGE_HANDLE, + "watch=%d", + eventLoop.handles[i].watch); + if (eventLoop.handles[i].ff) { + virFreeCallback ff = eventLoop.handles[i].ff; + void *opaque = eventLoop.handles[i].opaque; + virMutexUnlock(&eventLoop.lock); + ff(opaque); + virMutexLock(&eventLoop.lock); + } + + if ((i+1) < eventLoop.handlesCount) { + memmove(eventLoop.handles+i, + eventLoop.handles+i+1, + sizeof(struct virEventPollHandle)*(eventLoop.handlesCount + -(i+1))); + } + eventLoop.handlesCount--; + } + + /* Release some memory if we've got a big chunk free */ + gap = eventLoop.handlesAlloc - eventLoop.handlesCount; + if (eventLoop.handlesCount == 0 || + (gap > eventLoop.handlesCount && gap > EVENT_ALLOC_EXTENT)) { + EVENT_DEBUG("Found %zu out of %zu handles slots used, releasing %zu", + eventLoop.handlesCount, eventLoop.handlesAlloc, gap); + VIR_SHRINK_N(eventLoop.handles, eventLoop.handlesAlloc, gap); + } +} + +/* + * Run a single iteration of the event loop, blocking until + * at least one file handle has an event, or a timer expires + */ +int virEventPollRunOnce(void) { + struct pollfd *fds = NULL; + int ret, timeout, nfds; + + virMutexLock(&eventLoop.lock); + eventLoop.running = 1; + virThreadSelf(&eventLoop.leader); + + virEventPollCleanupTimeouts(); + virEventPollCleanupHandles(); + + if (!(fds = virEventPollMakePollFDs(&nfds)) || + virEventPollCalculateTimeout(&timeout) < 0) + goto error; + + virMutexUnlock(&eventLoop.lock); + + retry: + PROBE(EVENT_POLL_RUN, + "nhandles=%d timeout=%d", + nfds, timeout); + ret = poll(fds, nfds, timeout); + if (ret < 0) { + EVENT_DEBUG("Poll got error event %d", errno); + if (errno == EINTR || errno == EAGAIN) { + goto retry; + } + virReportSystemError(errno, "%s", + _("Unable to poll on file handles")); + goto error_unlocked; + } + EVENT_DEBUG("Poll got %d event(s)", ret); + + virMutexLock(&eventLoop.lock); + if (virEventPollDispatchTimeouts() < 0) + goto error; + + if (ret > 0 && + virEventPollDispatchHandles(nfds, fds) < 0) + goto error; + + virEventPollCleanupTimeouts(); + virEventPollCleanupHandles(); + + eventLoop.running = 0; + virMutexUnlock(&eventLoop.lock); + VIR_FREE(fds); + return 0; + +error: + virMutexUnlock(&eventLoop.lock); +error_unlocked: + VIR_FREE(fds); + return -1; +} + + +static void virEventPollHandleWakeup(int watch ATTRIBUTE_UNUSED, + int fd, + int events ATTRIBUTE_UNUSED, + void *opaque ATTRIBUTE_UNUSED) +{ + char c; + virMutexLock(&eventLoop.lock); + ignore_value(saferead(fd, &c, sizeof(c))); + virMutexUnlock(&eventLoop.lock); +} + +int virEventPollInit(void) +{ + if (virMutexInit(&eventLoop.lock) < 0) { + virReportSystemError(errno, "%s", + _("Unable to initialize mutex")); + return -1; + } + + if (pipe2(eventLoop.wakeupfd, O_CLOEXEC | O_NONBLOCK) < 0) { + virReportSystemError(errno, "%s", + _("Unable to setup wakeup pipe")); + return -1; + } + + if (virEventPollAddHandle(eventLoop.wakeupfd[0], + VIR_EVENT_HANDLE_READABLE, + virEventPollHandleWakeup, NULL, NULL) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unable to add handle %d to event loop"), + eventLoop.wakeupfd[0]); + VIR_FORCE_CLOSE(eventLoop.wakeupfd[0]); + VIR_FORCE_CLOSE(eventLoop.wakeupfd[1]); + return -1; + } + + return 0; +} + +static int virEventPollInterruptLocked(void) +{ + char c = '\0'; + + if (!eventLoop.running || + virThreadIsSelf(&eventLoop.leader)) { + VIR_DEBUG("Skip interrupt, %d %d", eventLoop.running, + virThreadID(&eventLoop.leader)); + return 0; + } + + VIR_DEBUG("Interrupting"); + if (safewrite(eventLoop.wakeupfd[1], &c, sizeof(c)) != sizeof(c)) + return -1; + return 0; +} + +int virEventPollInterrupt(void) +{ + int ret; + virMutexLock(&eventLoop.lock); + ret = virEventPollInterruptLocked(); + virMutexUnlock(&eventLoop.lock); + return ret; +} + +int +virEventPollToNativeEvents(int events) +{ + int ret = 0; + if (events & VIR_EVENT_HANDLE_READABLE) + ret |= POLLIN; + if (events & VIR_EVENT_HANDLE_WRITABLE) + ret |= POLLOUT; + if (events & VIR_EVENT_HANDLE_ERROR) + ret |= POLLERR; + if (events & VIR_EVENT_HANDLE_HANGUP) + ret |= POLLHUP; + return ret; +} + +int +virEventPollFromNativeEvents(int events) +{ + int ret = 0; + if (events & POLLIN) + ret |= VIR_EVENT_HANDLE_READABLE; + if (events & POLLOUT) + ret |= VIR_EVENT_HANDLE_WRITABLE; + if (events & POLLERR) + ret |= VIR_EVENT_HANDLE_ERROR; + if (events & POLLNVAL) /* Treat NVAL as error, since libvirt doesn't distinguish */ + ret |= VIR_EVENT_HANDLE_ERROR; + if (events & POLLHUP) + ret |= VIR_EVENT_HANDLE_HANGUP; + return ret; +} diff --git a/src/util/vireventpoll.h b/src/util/vireventpoll.h new file mode 100644 index 0000000..64b2e96 --- /dev/null +++ b/src/util/vireventpoll.h @@ -0,0 +1,132 @@ +/* + * event.h: event loop for monitoring file handles + * + * Copyright (C) 2007 Daniel P. Berrange + * Copyright (C) 2007 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>;. + * + * Author: Daniel P. Berrange <berrange(a)redhat.com&gt; + */ + +#ifndef __VIR_EVENT_POLL_H__ +# define __VIR_EVENT_POLL_H__ + +# include "internal.h" + +/** + * virEventPollAddHandle: register a callback for monitoring file handle events + * + * @fd: file handle to monitor for events + * @events: bitset of events to watch from POLLnnn constants + * @cb: callback to invoke when an event occurs + * @opaque: user data to pass to callback + * + * returns -1 if the file handle cannot be registered, 0 upon success + */ +int virEventPollAddHandle(int fd, int events, + virEventHandleCallback cb, + void *opaque, + virFreeCallback ff); + +/** + * virEventPollUpdateHandle: change event set for a monitored file handle + * + * @watch: watch whose handle to update + * @events: bitset of events to watch from POLLnnn constants + * + * Will not fail if fd exists + */ +void virEventPollUpdateHandle(int watch, int events); + +/** + * virEventPollRemoveHandle: unregister a callback from a file handle + * + * @watch: watch whose handle to remove + * + * returns -1 if the file handle was not registered, 0 upon success + */ +int virEventPollRemoveHandle(int watch); + +/** + * virEventPollAddTimeout: register a callback for a timer event + * + * @frequency: time between events in milliseconds + * @cb: callback to invoke when an event occurs + * @opaque: user data to pass to callback + * + * Setting frequency to -1 will disable the timer. Setting the frequency + * to zero will cause it to fire on every event loop iteration. + * + * returns -1 if the file handle cannot be registered, a positive + * integer timer id upon success + */ +int virEventPollAddTimeout(int frequency, + virEventTimeoutCallback cb, + void *opaque, + virFreeCallback ff); + +/** + * virEventPollUpdateTimeout: change frequency for a timer + * + * @timer: timer id to change + * @frequency: time between events in milliseconds + * + * Setting frequency to -1 will disable the timer. Setting the frequency + * to zero will cause it to fire on every event loop iteration. + * + * Will not fail if timer exists + */ +void virEventPollUpdateTimeout(int timer, int frequency); + +/** + * virEventPollRemoveTimeout: unregister a callback for a timer + * + * @timer: the timer id to remove + * + * returns -1 if the timer was not registered, 0 upon success + */ +int virEventPollRemoveTimeout(int timer); + +/** + * virEventPollInit: Initialize the event loop + * + * returns -1 if initialization failed + */ +int virEventPollInit(void); + +/** + * virEventPollRunOnce: run a single iteration of the event loop. + * + * Blocks the caller until at least one file handle has an + * event or the first timer expires. + * + * returns -1 if the event monitoring failed + */ +int virEventPollRunOnce(void); + +int virEventPollFromNativeEvents(int events); +int virEventPollToNativeEvents(int events); + + +/** + * virEventPollInterrupt: wakeup any thread waiting in poll() + * + * return -1 if wakup failed + */ +int virEventPollInterrupt(void); + + +#endif /* __VIRTD_EVENT_H__ */ diff --git a/tests/eventtest.c b/tests/eventtest.c index c087978..bc8d443 100644 --- a/tests/eventtest.c +++ b/tests/eventtest.c @@ -31,7 +31,7 @@ #include "threads.h" #include "logging.h" #include "util.h" -#include "event_poll.h" +#include "vireventpoll.h" #define NUM_FDS 31 #define NUM_TIME 31 diff --git a/tools/virsh.c b/tools/virsh.c index 07da077..5cb2e06 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -63,7 +63,6 @@ #include "xml.h" #include "libvirt/libvirt-qemu.h" #include "virfile.h" -#include "event_poll.h" #include "configmake.h" #include "threads.h" #include "vircommand.h" -- 1.7.11.7