summaryrefslogtreecommitdiff
path: root/libs/libevent/docs/epoll.c
diff options
context:
space:
mode:
Diffstat (limited to 'libs/libevent/docs/epoll.c')
-rw-r--r--libs/libevent/docs/epoll.c540
1 files changed, 0 insertions, 540 deletions
diff --git a/libs/libevent/docs/epoll.c b/libs/libevent/docs/epoll.c
deleted file mode 100644
index bf730b23db..0000000000
--- a/libs/libevent/docs/epoll.c
+++ /dev/null
@@ -1,540 +0,0 @@
-/*
- * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
- * Copyright 2007-2012 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 "evconfig-private.h"
-
-#ifdef EVENT__HAVE_EPOLL
-
-#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
-#ifdef EVENT__HAVE_SYS_TIMERFD_H
-#include <sys/timerfd.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"
-#include "time-internal.h"
-
-/* Since Linux 2.6.17, epoll is able to report about peer half-closed connection
- using special EPOLLRDHUP flag on a read event.
-*/
-#if !defined(EPOLLRDHUP)
-#define EPOLLRDHUP 0
-#define EARLY_CLOSE_IF_HAVE_RDHUP 0
-#else
-#define EARLY_CLOSE_IF_HAVE_RDHUP EV_FEATURE_EARLY_CLOSE
-#endif
-
-#include "epolltable-internal.h"
-
-#if defined(EVENT__HAVE_SYS_TIMERFD_H) && \
- defined(EVENT__HAVE_TIMERFD_CREATE) && \
- defined(HAVE_POSIX_MONOTONIC) && defined(TFD_NONBLOCK) && \
- defined(TFD_CLOEXEC)
-/* Note that we only use timerfd if TFD_NONBLOCK and TFD_CLOEXEC are available
- and working. This means that we can't support it on 2.6.25 (where timerfd
- was introduced) or 2.6.26, since 2.6.27 introduced those flags.
- */
-#define USING_TIMERFD
-#endif
-
-struct epollop {
- struct epoll_event *events;
- int nevents;
- int epfd;
-#ifdef USING_TIMERFD
- int timerfd;
-#endif
-};
-
-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| EARLY_CLOSE_IF_HAVE_RDHUP,
- 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|EV_FEATURE_EARLY_CLOSE,
- 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 = -1;
- struct epollop *epollop;
-
-#ifdef EVENT__HAVE_EPOLL_CREATE1
- /* First, try the shiny new epoll_create1 interface, if we have it. */
- epfd = epoll_create1(EPOLL_CLOEXEC);
-#endif
- if (epfd == -1) {
- /* Initialize the kernel queue using the old interface. (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)))) {
- close(epfd);
- return (NULL);
- }
-
- epollop->epfd = epfd;
-
- /* Initialize fields */
- epollop->events = mm_calloc(INITIAL_NEVENT, sizeof(struct epoll_event));
- if (epollop->events == NULL) {
- mm_free(epollop);
- close(epfd);
- 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;
- }
-
-#ifdef USING_TIMERFD
- /*
- The epoll interface ordinarily gives us one-millisecond precision,
- so on Linux it makes perfect sense to use the CLOCK_MONOTONIC_COARSE
- timer. But when the user has set the new PRECISE_TIMER flag for an
- event_base, we can try to use timerfd to give them finer granularity.
- */
- if ((base->flags & EVENT_BASE_FLAG_PRECISE_TIMER) &&
- base->monotonic_timer.monotonic_clock == CLOCK_MONOTONIC) {
- int fd;
- fd = epollop->timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC);
- if (epollop->timerfd >= 0) {
- struct epoll_event epev;
- memset(&epev, 0, sizeof(epev));
- epev.data.fd = epollop->timerfd;
- epev.events = EPOLLIN;
- if (epoll_ctl(epollop->epfd, EPOLL_CTL_ADD, fd, &epev) < 0) {
- event_warn("epoll_ctl(timerfd)");
- close(fd);
- epollop->timerfd = -1;
- }
- } else {
- if (errno != EINVAL && errno != ENOSYS) {
- /* These errors probably mean that we were
- * compiled with timerfd/TFD_* support, but
- * we're running on a kernel that lacks those.
- */
- event_warn("timerfd_create");
- }
- epollop->timerfd = -1;
- }
- } else {
- epollop->timerfd = -1;
- }
-#endif
-
- 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":
- "???";
-}
-
-#define PRINT_CHANGES(op, events, ch, status) \
- "Epoll %s(%d) on fd %d " status ". " \
- "Old events were %d; " \
- "read change was %d (%s); " \
- "write change was %d (%s); " \
- "close change was %d (%s)", \
- epoll_op_to_string(op), \
- events, \
- ch->fd, \
- ch->old_events, \
- ch->read_change, \
- change_to_string(ch->read_change), \
- ch->write_change, \
- change_to_string(ch->write_change), \
- ch->close_change, \
- change_to_string(ch->close_change)
-
-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;
- int idx;
-
- idx = EPOLL_OP_TABLE_INDEX(ch);
- op = epoll_op_table[idx].op;
- events = epoll_op_table[idx].events;
-
- if (!events) {
- EVUTIL_ASSERT(op == 0);
- return 0;
- }
-
- if ((ch->read_change|ch->write_change) & EV_CHANGE_ET)
- events |= EPOLLET;
-
- memset(&epev, 0, sizeof(epev));
- epev.data.fd = ch->fd;
- epev.events = events;
- if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == 0) {
- event_debug((PRINT_CHANGES(op, epev.events, ch, "okay")));
- return 0;
- }
-
- switch (op) {
- case EPOLL_CTL_MOD:
- if (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));
- return 0;
- }
- }
- break;
- case EPOLL_CTL_ADD:
- if (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));
- return 0;
- }
- }
- break;
- case EPOLL_CTL_DEL:
- if (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)));
- return 0;
- }
- break;
- default:
- break;
- }
-
- event_warn(PRINT_CHANGES(op, epev.events, ch, "failed"));
- return -1;
-}
-
-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 = ch.close_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);
- if (events & EV_CLOSED)
- ch.close_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 = ch.close_change = 0;
- if (events & EV_WRITE)
- ch.write_change = EV_CHANGE_DEL;
- if (events & EV_READ)
- ch.read_change = EV_CHANGE_DEL;
- if (events & EV_CLOSED)
- ch.close_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;
-
-#ifdef USING_TIMERFD
- if (epollop->timerfd >= 0) {
- struct itimerspec is;
- is.it_interval.tv_sec = 0;
- is.it_interval.tv_nsec = 0;
- if (tv == NULL) {
- /* No timeout; disarm the timer. */
- is.it_value.tv_sec = 0;
- is.it_value.tv_nsec = 0;
- } else {
- if (tv->tv_sec == 0 && tv->tv_usec == 0) {
- /* we need to exit immediately; timerfd can't
- * do that. */
- timeout = 0;
- }
- is.it_value.tv_sec = tv->tv_sec;
- is.it_value.tv_nsec = tv->tv_usec * 1000;
- }
- /* TODO: we could avoid unnecessary syscalls here by only
- calling timerfd_settime when the top timeout changes, or
- when we're called with a different timeval.
- */
- if (timerfd_settime(epollop->timerfd, 0, &is, NULL) < 0) {
- event_warn("timerfd_settime");
- }
- } else
-#endif
- 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;
-#ifdef USING_TIMERFD
- if (events[i].data.fd == epollop->timerfd)
- continue;
-#endif
-
- if (what & (EPOLLHUP|EPOLLERR)) {
- ev = EV_READ | EV_WRITE;
- } else {
- if (what & EPOLLIN)
- ev |= EV_READ;
- if (what & EPOLLOUT)
- ev |= EV_WRITE;
- if (what & EPOLLRDHUP)
- ev |= EV_CLOSED;
- }
-
- 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);
-#ifdef USING_TIMERFD
- if (epollop->timerfd >= 0)
- close(epollop->timerfd);
-#endif
-
- memset(epollop, 0, sizeof(struct epollop));
- mm_free(epollop);
-}
-
-#endif /* EVENT__HAVE_EPOLL */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-27 21:45:11 +0000