diff options
Diffstat (limited to 'ipc/chromium/src/third_party/libevent/poll.c')
-rw-r--r-- | ipc/chromium/src/third_party/libevent/poll.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/ipc/chromium/src/third_party/libevent/poll.c b/ipc/chromium/src/third_party/libevent/poll.c new file mode 100644 index 000000000..04d311bb6 --- /dev/null +++ b/ipc/chromium/src/third_party/libevent/poll.c @@ -0,0 +1,333 @@ +/* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */ + +/* + * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu> + * Copyright 2007-2012 Niels Provos and 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 <sys/types.h> +#ifdef _EVENT_HAVE_SYS_TIME_H +#include <sys/time.h> +#endif +#include <sys/queue.h> +#include <poll.h> +#include <signal.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> + +#include "event-internal.h" +#include "evsignal-internal.h" +#include "log-internal.h" +#include "evmap-internal.h" +#include "event2/thread.h" +#include "evthread-internal.h" + +struct pollidx { + int idxplus1; +}; + +struct pollop { + int event_count; /* Highest number alloc */ + int nfds; /* Highest number used */ + int realloc_copy; /* True iff we must realloc + * event_set_copy */ + struct pollfd *event_set; + struct pollfd *event_set_copy; +}; + +static void *poll_init(struct event_base *); +static int poll_add(struct event_base *, int, short old, short events, void *_idx); +static int poll_del(struct event_base *, int, short old, short events, void *_idx); +static int poll_dispatch(struct event_base *, struct timeval *); +static void poll_dealloc(struct event_base *); + +const struct eventop pollops = { + "poll", + poll_init, + poll_add, + poll_del, + poll_dispatch, + poll_dealloc, + 0, /* doesn't need_reinit */ + EV_FEATURE_FDS, + sizeof(struct pollidx), +}; + +static void * +poll_init(struct event_base *base) +{ + struct pollop *pollop; + + if (!(pollop = mm_calloc(1, sizeof(struct pollop)))) + return (NULL); + + evsig_init(base); + + return (pollop); +} + +#ifdef CHECK_INVARIANTS +static void +poll_check_ok(struct pollop *pop) +{ + int i, idx; + struct event *ev; + + for (i = 0; i < pop->fd_count; ++i) { + idx = pop->idxplus1_by_fd[i]-1; + if (idx < 0) + continue; + EVUTIL_ASSERT(pop->event_set[idx].fd == i); + } + for (i = 0; i < pop->nfds; ++i) { + struct pollfd *pfd = &pop->event_set[i]; + EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1); + } +} +#else +#define poll_check_ok(pop) +#endif + +static int +poll_dispatch(struct event_base *base, struct timeval *tv) +{ + int res, i, j, nfds; + long msec = -1; + struct pollop *pop = base->evbase; + struct pollfd *event_set; + + poll_check_ok(pop); + + nfds = pop->nfds; + +#ifndef _EVENT_DISABLE_THREAD_SUPPORT + if (base->th_base_lock) { + /* If we're using this backend in a multithreaded setting, + * then we need to work on a copy of event_set, so that we can + * let other threads modify the main event_set while we're + * polling. If we're not multithreaded, then we'll skip the + * copy step here to save memory and time. */ + if (pop->realloc_copy) { + struct pollfd *tmp = mm_realloc(pop->event_set_copy, + pop->event_count * sizeof(struct pollfd)); + if (tmp == NULL) { + event_warn("realloc"); + return -1; + } + pop->event_set_copy = tmp; + pop->realloc_copy = 0; + } + memcpy(pop->event_set_copy, pop->event_set, + sizeof(struct pollfd)*nfds); + event_set = pop->event_set_copy; + } else { + event_set = pop->event_set; + } +#else + event_set = pop->event_set; +#endif + + if (tv != NULL) { + msec = evutil_tv_to_msec(tv); + if (msec < 0 || msec > INT_MAX) + msec = INT_MAX; + } + + EVBASE_RELEASE_LOCK(base, th_base_lock); + + res = poll(event_set, nfds, msec); + + EVBASE_ACQUIRE_LOCK(base, th_base_lock); + + if (res == -1) { + if (errno != EINTR) { + event_warn("poll"); + return (-1); + } + + return (0); + } + + event_debug(("%s: poll reports %d", __func__, res)); + + if (res == 0 || nfds == 0) + return (0); + + i = random() % nfds; + for (j = 0; j < nfds; j++) { + int what; + if (++i == nfds) + i = 0; + what = event_set[i].revents; + if (!what) + continue; + + res = 0; + + /* If the file gets closed notify */ + if (what & (POLLHUP|POLLERR)) + what |= POLLIN|POLLOUT; + if (what & POLLIN) + res |= EV_READ; + if (what & POLLOUT) + res |= EV_WRITE; + if (res == 0) + continue; + + evmap_io_active(base, event_set[i].fd, res); + } + + return (0); +} + +static int +poll_add(struct event_base *base, int fd, short old, short events, void *_idx) +{ + struct pollop *pop = base->evbase; + struct pollfd *pfd = NULL; + struct pollidx *idx = _idx; + int i; + + EVUTIL_ASSERT((events & EV_SIGNAL) == 0); + if (!(events & (EV_READ|EV_WRITE))) + return (0); + + poll_check_ok(pop); + if (pop->nfds + 1 >= pop->event_count) { + struct pollfd *tmp_event_set; + int tmp_event_count; + + if (pop->event_count < 32) + tmp_event_count = 32; + else + tmp_event_count = pop->event_count * 2; + + /* We need more file descriptors */ + tmp_event_set = mm_realloc(pop->event_set, + tmp_event_count * sizeof(struct pollfd)); + if (tmp_event_set == NULL) { + event_warn("realloc"); + return (-1); + } + pop->event_set = tmp_event_set; + + pop->event_count = tmp_event_count; + pop->realloc_copy = 1; + } + + i = idx->idxplus1 - 1; + + if (i >= 0) { + pfd = &pop->event_set[i]; + } else { + i = pop->nfds++; + pfd = &pop->event_set[i]; + pfd->events = 0; + pfd->fd = fd; + idx->idxplus1 = i + 1; + } + + pfd->revents = 0; + if (events & EV_WRITE) + pfd->events |= POLLOUT; + if (events & EV_READ) + pfd->events |= POLLIN; + poll_check_ok(pop); + + return (0); +} + +/* + * Nothing to be done here. + */ + +static int +poll_del(struct event_base *base, int fd, short old, short events, void *_idx) +{ + struct pollop *pop = base->evbase; + struct pollfd *pfd = NULL; + struct pollidx *idx = _idx; + int i; + + EVUTIL_ASSERT((events & EV_SIGNAL) == 0); + if (!(events & (EV_READ|EV_WRITE))) + return (0); + + poll_check_ok(pop); + i = idx->idxplus1 - 1; + if (i < 0) + return (-1); + + /* Do we still want to read or write? */ + pfd = &pop->event_set[i]; + if (events & EV_READ) + pfd->events &= ~POLLIN; + if (events & EV_WRITE) + pfd->events &= ~POLLOUT; + poll_check_ok(pop); + if (pfd->events) + /* Another event cares about that fd. */ + return (0); + + /* Okay, so we aren't interested in that fd anymore. */ + idx->idxplus1 = 0; + + --pop->nfds; + if (i != pop->nfds) { + /* + * Shift the last pollfd down into the now-unoccupied + * position. + */ + memcpy(&pop->event_set[i], &pop->event_set[pop->nfds], + sizeof(struct pollfd)); + idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd); + EVUTIL_ASSERT(idx); + EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1); + idx->idxplus1 = i + 1; + } + + poll_check_ok(pop); + return (0); +} + +static void +poll_dealloc(struct event_base *base) +{ + struct pollop *pop = base->evbase; + + evsig_dealloc(base); + if (pop->event_set) + mm_free(pop->event_set); + if (pop->event_set_copy) + mm_free(pop->event_set_copy); + + memset(pop, 0, sizeof(struct pollop)); + mm_free(pop); +} |