--- /dev/null
+/*
+ * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * Copyright 2007-2010 Niels Provos, Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "event2/event-config.h"
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/resource.h>
+#ifdef _EVENT_HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#include <sys/queue.h>
+#include <sys/epoll.h>
+#include <signal.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifdef _EVENT_HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#include "event-internal.h"
+#include "evsignal-internal.h"
+#include "event2/thread.h"
+#include "evthread-internal.h"
+#include "log-internal.h"
+#include "evmap-internal.h"
+#include "changelist-internal.h"
+
+struct epollop {
+ struct epoll_event *events;
+ int nevents;
+ int epfd;
+};
+
+static void *epoll_init(struct event_base *);
+static int epoll_dispatch(struct event_base *, struct timeval *);
+static void epoll_dealloc(struct event_base *);
+
+static const struct eventop epollops_changelist = {
+ "epoll (with changelist)",
+ epoll_init,
+ event_changelist_add,
+ event_changelist_del,
+ epoll_dispatch,
+ epoll_dealloc,
+ 1, /* need reinit */
+ EV_FEATURE_ET|EV_FEATURE_O1,
+ EVENT_CHANGELIST_FDINFO_SIZE
+};
+
+
+static int epoll_nochangelist_add(struct event_base *base, evutil_socket_t fd,
+ short old, short events, void *p);
+static int epoll_nochangelist_del(struct event_base *base, evutil_socket_t fd,
+ short old, short events, void *p);
+
+const struct eventop epollops = {
+ "epoll",
+ epoll_init,
+ epoll_nochangelist_add,
+ epoll_nochangelist_del,
+ epoll_dispatch,
+ epoll_dealloc,
+ 1, /* need reinit */
+ EV_FEATURE_ET|EV_FEATURE_O1,
+ 0
+};
+
+#define INITIAL_NEVENT 32
+#define MAX_NEVENT 4096
+
+/* On Linux kernels at least up to 2.6.24.4, epoll can't handle timeout
+ * values bigger than (LONG_MAX - 999ULL)/HZ. HZ in the wild can be
+ * as big as 1000, and LONG_MAX can be as small as (1<<31)-1, so the
+ * largest number of msec we can support here is 2147482. Let's
+ * round that down by 47 seconds.
+ */
+#define MAX_EPOLL_TIMEOUT_MSEC (35*60*1000)
+
+static void *
+epoll_init(struct event_base *base)
+{
+ int epfd;
+ struct epollop *epollop;
+
+ /* Initialize the kernel queue. (The size field is ignored since
+ * 2.6.8.) */
+ if ((epfd = epoll_create(32000)) == -1) {
+ if (errno != ENOSYS)
+ event_warn("epoll_create");
+ return (NULL);
+ }
+
+ evutil_make_socket_closeonexec(epfd);
+
+ if (!(epollop = mm_calloc(1, sizeof(struct epollop))))
+ return (NULL);
+
+ epollop->epfd = epfd;
+
+ /* Initialize fields */
+ epollop->events = mm_calloc(INITIAL_NEVENT, sizeof(struct epoll_event));
+ if (epollop->events == NULL) {
+ mm_free(epollop);
+ return (NULL);
+ }
+ epollop->nevents = INITIAL_NEVENT;
+
+ if ((base->flags & EVENT_BASE_FLAG_EPOLL_USE_CHANGELIST) != 0 ||
+ ((base->flags & EVENT_BASE_FLAG_IGNORE_ENV) == 0 &&
+ evutil_getenv("EVENT_EPOLL_USE_CHANGELIST") != NULL))
+ base->evsel = &epollops_changelist;
+
+ evsig_init(base);
+
+ return (epollop);
+}
+
+static const char *
+change_to_string(int change)
+{
+ change &= (EV_CHANGE_ADD|EV_CHANGE_DEL);
+ if (change == EV_CHANGE_ADD) {
+ return "add";
+ } else if (change == EV_CHANGE_DEL) {
+ return "del";
+ } else if (change == 0) {
+ return "none";
+ } else {
+ return "???";
+ }
+}
+
+static const char *
+epoll_op_to_string(int op)
+{
+ return op == EPOLL_CTL_ADD?"ADD":
+ op == EPOLL_CTL_DEL?"DEL":
+ op == EPOLL_CTL_MOD?"MOD":
+ "???";
+}
+
+static int
+epoll_apply_one_change(struct event_base *base,
+ struct epollop *epollop,
+ const struct event_change *ch)
+{
+ struct epoll_event epev;
+ int op, events = 0;
+
+ if (1) {
+ /* The logic here is a little tricky. If we had no events set
+ on the fd before, we need to set op="ADD" and set
+ events=the events we want to add. If we had any events set
+ on the fd before, and we want any events to remain on the
+ fd, we need to say op="MOD" and set events=the events we
+ want to remain. But if we want to delete the last event,
+ we say op="DEL" and set events=the remaining events. What
+ fun!
+ */
+
+ /* TODO: Turn this into a switch or a table lookup. */
+
+ if ((ch->read_change & EV_CHANGE_ADD) ||
+ (ch->write_change & EV_CHANGE_ADD)) {
+ /* If we are adding anything at all, we'll want to do
+ * either an ADD or a MOD. */
+ events = 0;
+ op = EPOLL_CTL_ADD;
+ if (ch->read_change & EV_CHANGE_ADD) {
+ events |= EPOLLIN;
+ } else if (ch->read_change & EV_CHANGE_DEL) {
+ ;
+ } else if (ch->old_events & EV_READ) {
+ events |= EPOLLIN;
+ }
+ if (ch->write_change & EV_CHANGE_ADD) {
+ events |= EPOLLOUT;
+ } else if (ch->write_change & EV_CHANGE_DEL) {
+ ;
+ } else if (ch->old_events & EV_WRITE) {
+ events |= EPOLLOUT;
+ }
+ if ((ch->read_change|ch->write_change) & EV_ET)
+ events |= EPOLLET;
+
+ if (ch->old_events) {
+ /* If MOD fails, we retry as an ADD, and if
+ * ADD fails we will retry as a MOD. So the
+ * only hard part here is to guess which one
+ * will work. As a heuristic, we'll try
+ * MOD first if we think there were old
+ * events and ADD if we think there were none.
+ *
+ * We can be wrong about the MOD if the file
+ * has in fact been closed and re-opened.
+ *
+ * We can be wrong about the ADD if the
+ * the fd has been re-created with a dup()
+ * of the same file that it was before.
+ */
+ op = EPOLL_CTL_MOD;
+ }
+ } else if ((ch->read_change & EV_CHANGE_DEL) ||
+ (ch->write_change & EV_CHANGE_DEL)) {
+ /* If we're deleting anything, we'll want to do a MOD
+ * or a DEL. */
+ op = EPOLL_CTL_DEL;
+
+ if (ch->read_change & EV_CHANGE_DEL) {
+ if (ch->write_change & EV_CHANGE_DEL) {
+ events = EPOLLIN|EPOLLOUT;
+ } else if (ch->old_events & EV_WRITE) {
+ events = EPOLLOUT;
+ op = EPOLL_CTL_MOD;
+ } else {
+ events = EPOLLIN;
+ }
+ } else if (ch->write_change & EV_CHANGE_DEL) {
+ if (ch->old_events & EV_READ) {
+ events = EPOLLIN;
+ op = EPOLL_CTL_MOD;
+ } else {
+ events = EPOLLOUT;
+ }
+ }
+ }
+
+ if (!events)
+ return 0;
+
+ memset(&epev, 0, sizeof(epev));
+ epev.data.fd = ch->fd;
+ epev.events = events;
+ if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == -1) {
+ if (op == EPOLL_CTL_MOD && errno == ENOENT) {
+ /* If a MOD operation fails with ENOENT, the
+ * fd was probably closed and re-opened. We
+ * should retry the operation as an ADD.
+ */
+ if (epoll_ctl(epollop->epfd, EPOLL_CTL_ADD, ch->fd, &epev) == -1) {
+ event_warn("Epoll MOD(%d) on %d retried as ADD; that failed too",
+ (int)epev.events, ch->fd);
+ return -1;
+ } else {
+ event_debug(("Epoll MOD(%d) on %d retried as ADD; succeeded.",
+ (int)epev.events,
+ ch->fd));
+ }
+ } else if (op == EPOLL_CTL_ADD && errno == EEXIST) {
+ /* If an ADD operation fails with EEXIST,
+ * either the operation was redundant (as with a
+ * precautionary add), or we ran into a fun
+ * kernel bug where using dup*() to duplicate the
+ * same file into the same fd gives you the same epitem
+ * rather than a fresh one. For the second case,
+ * we must retry with MOD. */
+ if (epoll_ctl(epollop->epfd, EPOLL_CTL_MOD, ch->fd, &epev) == -1) {
+ event_warn("Epoll ADD(%d) on %d retried as MOD; that failed too",
+ (int)epev.events, ch->fd);
+ return -1;
+ } else {
+ event_debug(("Epoll ADD(%d) on %d retried as MOD; succeeded.",
+ (int)epev.events,
+ ch->fd));
+ }
+ } else if (op == EPOLL_CTL_DEL &&
+ (errno == ENOENT || errno == EBADF ||
+ errno == EPERM)) {
+ /* If a delete fails with one of these errors,
+ * that's fine too: we closed the fd before we
+ * got around to calling epoll_dispatch. */
+ event_debug(("Epoll DEL(%d) on fd %d gave %s: DEL was unnecessary.",
+ (int)epev.events,
+ ch->fd,
+ strerror(errno)));
+ } else {
+ event_warn("Epoll %s(%d) on fd %d failed. Old events were %d; read change was %d (%s); write change was %d (%s)",
+ epoll_op_to_string(op),
+ (int)epev.events,
+ ch->fd,
+ ch->old_events,
+ ch->read_change,
+ change_to_string(ch->read_change),
+ ch->write_change,
+ change_to_string(ch->write_change));
+ return -1;
+ }
+ } else {
+ event_debug(("Epoll %s(%d) on fd %d okay. [old events were %d; read change was %d; write change was %d]",
+ epoll_op_to_string(op),
+ (int)epev.events,
+ (int)ch->fd,
+ ch->old_events,
+ ch->read_change,
+ ch->write_change));
+ }
+ }
+ return 0;
+}
+
+static int
+epoll_apply_changes(struct event_base *base)
+{
+ struct event_changelist *changelist = &base->changelist;
+ struct epollop *epollop = base->evbase;
+ struct event_change *ch;
+
+ int r = 0;
+ int i;
+
+ for (i = 0; i < changelist->n_changes; ++i) {
+ ch = &changelist->changes[i];
+ if (epoll_apply_one_change(base, epollop, ch) < 0)
+ r = -1;
+ }
+
+ return (r);
+}
+
+static int
+epoll_nochangelist_add(struct event_base *base, evutil_socket_t fd,
+ short old, short events, void *p)
+{
+ struct event_change ch;
+ ch.fd = fd;
+ ch.old_events = old;
+ ch.read_change = ch.write_change = 0;
+ if (events & EV_WRITE)
+ ch.write_change = EV_CHANGE_ADD |
+ (events & EV_ET);
+ if (events & EV_READ)
+ ch.read_change = EV_CHANGE_ADD |
+ (events & EV_ET);
+
+ return epoll_apply_one_change(base, base->evbase, &ch);
+}
+
+static int
+epoll_nochangelist_del(struct event_base *base, evutil_socket_t fd,
+ short old, short events, void *p)
+{
+ struct event_change ch;
+ ch.fd = fd;
+ ch.old_events = old;
+ ch.read_change = ch.write_change = 0;
+ if (events & EV_WRITE)
+ ch.write_change = EV_CHANGE_DEL;
+ if (events & EV_READ)
+ ch.read_change = EV_CHANGE_DEL;
+
+ return epoll_apply_one_change(base, base->evbase, &ch);
+}
+
+static int
+epoll_dispatch(struct event_base *base, struct timeval *tv)
+{
+ struct epollop *epollop = base->evbase;
+ struct epoll_event *events = epollop->events;
+ int i, res;
+ long timeout = -1;
+
+ if (tv != NULL) {
+ timeout = evutil_tv_to_msec(tv);
+ if (timeout < 0 || timeout > MAX_EPOLL_TIMEOUT_MSEC) {
+ /* Linux kernels can wait forever if the timeout is
+ * too big; see comment on MAX_EPOLL_TIMEOUT_MSEC. */
+ timeout = MAX_EPOLL_TIMEOUT_MSEC;
+ }
+ }
+
+ epoll_apply_changes(base);
+ event_changelist_remove_all(&base->changelist, base);
+
+ EVBASE_RELEASE_LOCK(base, th_base_lock);
+
+ res = epoll_wait(epollop->epfd, events, epollop->nevents, timeout);
+
+ EVBASE_ACQUIRE_LOCK(base, th_base_lock);
+
+ if (res == -1) {
+ if (errno != EINTR) {
+ event_warn("epoll_wait");
+ return (-1);
+ }
+
+ return (0);
+ }
+
+ event_debug(("%s: epoll_wait reports %d", __func__, res));
+ EVUTIL_ASSERT(res <= epollop->nevents);
+
+ for (i = 0; i < res; i++) {
+ int what = events[i].events;
+ short ev = 0;
+
+ if (what & (EPOLLHUP|EPOLLERR)) {
+ ev = EV_READ | EV_WRITE;
+ } else {
+ if (what & EPOLLIN)
+ ev |= EV_READ;
+ if (what & EPOLLOUT)
+ ev |= EV_WRITE;
+ }
+
+ if (!ev)
+ continue;
+
+ evmap_io_active(base, events[i].data.fd, ev | EV_ET);
+ }
+
+ if (res == epollop->nevents && epollop->nevents < MAX_NEVENT) {
+ /* We used all of the event space this time. We should
+ be ready for more events next time. */
+ int new_nevents = epollop->nevents * 2;
+ struct epoll_event *new_events;
+
+ new_events = mm_realloc(epollop->events,
+ new_nevents * sizeof(struct epoll_event));
+ if (new_events) {
+ epollop->events = new_events;
+ epollop->nevents = new_nevents;
+ }
+ }
+
+ return (0);
+}
+
+
+static void
+epoll_dealloc(struct event_base *base)
+{
+ struct epollop *epollop = base->evbase;
+
+ evsig_dealloc(base);
+ if (epollop->events)
+ mm_free(epollop->events);
+ if (epollop->epfd >= 0)
+ close(epollop->epfd);
+
+ memset(epollop, 0, sizeof(struct epollop));
+ mm_free(epollop);
+}
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