359 lines
8.4 KiB
C
359 lines
8.4 KiB
C
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/* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
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/*
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* Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
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* Copyright 2007-2012 Niels Provos and Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "event2/event-config.h"
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#include "evconfig-private.h"
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#ifdef EVENT__HAVE_POLL
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#include <sys/types.h>
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#ifdef EVENT__HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#include <sys/queue.h>
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#include <poll.h>
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#include <signal.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include "event-internal.h"
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#include "evsignal-internal.h"
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#include "log-internal.h"
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#include "evmap-internal.h"
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#include "event2/thread.h"
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#include "evthread-internal.h"
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#include "time-internal.h"
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/* Since Linux 2.6.17, poll is able to report about peer half-closed connection
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using special POLLRDHUP flag on a read event.
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*/
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#if !defined(POLLRDHUP)
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#define POLLRDHUP 0
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#define EARLY_CLOSE_IF_HAVE_RDHUP 0
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#else
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#define EARLY_CLOSE_IF_HAVE_RDHUP EV_FEATURE_EARLY_CLOSE
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#endif
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struct pollidx {
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int idxplus1;
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};
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struct pollop {
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int event_count; /* Highest number alloc */
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int nfds; /* Highest number used */
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int realloc_copy; /* True iff we must realloc
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* event_set_copy */
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struct pollfd *event_set;
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struct pollfd *event_set_copy;
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};
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static void *poll_init(struct event_base *);
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static int poll_add(struct event_base *, int, short old, short events, void *idx);
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static int poll_del(struct event_base *, int, short old, short events, void *idx);
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static int poll_dispatch(struct event_base *, struct timeval *);
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static void poll_dealloc(struct event_base *);
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const struct eventop pollops = {
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"poll",
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poll_init,
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poll_add,
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poll_del,
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poll_dispatch,
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poll_dealloc,
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1, /* need_reinit */
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EV_FEATURE_FDS|EARLY_CLOSE_IF_HAVE_RDHUP,
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sizeof(struct pollidx),
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};
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static void *
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poll_init(struct event_base *base)
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{
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struct pollop *pollop;
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if (!(pollop = mm_calloc(1, sizeof(struct pollop))))
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return (NULL);
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evsig_init_(base);
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evutil_weakrand_seed_(&base->weakrand_seed, 0);
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return (pollop);
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}
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#ifdef CHECK_INVARIANTS
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static void
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poll_check_ok(struct pollop *pop)
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{
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int i, idx;
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struct event *ev;
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for (i = 0; i < pop->fd_count; ++i) {
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idx = pop->idxplus1_by_fd[i]-1;
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if (idx < 0)
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continue;
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EVUTIL_ASSERT(pop->event_set[idx].fd == i);
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}
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for (i = 0; i < pop->nfds; ++i) {
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struct pollfd *pfd = &pop->event_set[i];
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EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1);
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}
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}
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#else
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#define poll_check_ok(pop)
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#endif
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static int
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poll_dispatch(struct event_base *base, struct timeval *tv)
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{
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int res, i, j, nfds;
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long msec = -1;
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struct pollop *pop = base->evbase;
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struct pollfd *event_set;
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poll_check_ok(pop);
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nfds = pop->nfds;
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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if (base->th_base_lock) {
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/* If we're using this backend in a multithreaded setting,
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* then we need to work on a copy of event_set, so that we can
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* let other threads modify the main event_set while we're
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* polling. If we're not multithreaded, then we'll skip the
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* copy step here to save memory and time. */
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if (pop->realloc_copy) {
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struct pollfd *tmp = mm_realloc(pop->event_set_copy,
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pop->event_count * sizeof(struct pollfd));
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if (tmp == NULL) {
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event_warn("realloc");
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return -1;
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}
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pop->event_set_copy = tmp;
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pop->realloc_copy = 0;
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}
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memcpy(pop->event_set_copy, pop->event_set,
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sizeof(struct pollfd)*nfds);
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event_set = pop->event_set_copy;
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} else {
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event_set = pop->event_set;
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}
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#else
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event_set = pop->event_set;
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#endif
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if (tv != NULL) {
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msec = evutil_tv_to_msec_(tv);
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if (msec < 0 || msec > INT_MAX)
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msec = INT_MAX;
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}
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EVBASE_RELEASE_LOCK(base, th_base_lock);
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res = poll(event_set, nfds, msec);
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EVBASE_ACQUIRE_LOCK(base, th_base_lock);
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if (res == -1) {
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if (errno != EINTR) {
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event_warn("poll");
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return (-1);
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}
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return (0);
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}
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event_debug(("%s: poll reports %d", __func__, res));
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if (res == 0 || nfds == 0)
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return (0);
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i = evutil_weakrand_range_(&base->weakrand_seed, nfds);
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for (j = 0; j < nfds; j++) {
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int what;
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if (++i == nfds)
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i = 0;
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what = event_set[i].revents;
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if (!what)
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continue;
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res = 0;
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/* If the file gets closed notify */
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if (what & (POLLHUP|POLLERR|POLLNVAL))
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what |= POLLIN|POLLOUT;
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if (what & POLLIN)
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res |= EV_READ;
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if (what & POLLOUT)
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res |= EV_WRITE;
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if (what & POLLRDHUP)
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res |= EV_CLOSED;
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if (res == 0)
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continue;
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evmap_io_active_(base, event_set[i].fd, res);
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}
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return (0);
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}
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static int
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poll_add(struct event_base *base, int fd, short old, short events, void *idx_)
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{
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struct pollop *pop = base->evbase;
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struct pollfd *pfd = NULL;
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struct pollidx *idx = idx_;
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int i;
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EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
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if (!(events & (EV_READ|EV_WRITE|EV_CLOSED)))
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return (0);
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poll_check_ok(pop);
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if (pop->nfds + 1 >= pop->event_count) {
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struct pollfd *tmp_event_set;
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int tmp_event_count;
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if (pop->event_count < 32)
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tmp_event_count = 32;
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else
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tmp_event_count = pop->event_count * 2;
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/* We need more file descriptors */
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tmp_event_set = mm_realloc(pop->event_set,
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tmp_event_count * sizeof(struct pollfd));
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if (tmp_event_set == NULL) {
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event_warn("realloc");
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return (-1);
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}
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pop->event_set = tmp_event_set;
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pop->event_count = tmp_event_count;
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pop->realloc_copy = 1;
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}
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i = idx->idxplus1 - 1;
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if (i >= 0) {
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pfd = &pop->event_set[i];
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} else {
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i = pop->nfds++;
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pfd = &pop->event_set[i];
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pfd->events = 0;
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pfd->fd = fd;
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idx->idxplus1 = i + 1;
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}
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pfd->revents = 0;
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if (events & EV_WRITE)
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pfd->events |= POLLOUT;
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if (events & EV_READ)
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pfd->events |= POLLIN;
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if (events & EV_CLOSED)
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pfd->events |= POLLRDHUP;
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poll_check_ok(pop);
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return (0);
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}
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/*
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* Nothing to be done here.
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*/
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static int
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poll_del(struct event_base *base, int fd, short old, short events, void *idx_)
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{
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struct pollop *pop = base->evbase;
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struct pollfd *pfd = NULL;
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struct pollidx *idx = idx_;
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int i;
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EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
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if (!(events & (EV_READ|EV_WRITE|EV_CLOSED)))
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return (0);
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poll_check_ok(pop);
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i = idx->idxplus1 - 1;
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if (i < 0)
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return (-1);
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/* Do we still want to read or write? */
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pfd = &pop->event_set[i];
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if (events & EV_READ)
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pfd->events &= ~POLLIN;
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if (events & EV_WRITE)
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pfd->events &= ~POLLOUT;
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if (events & EV_CLOSED)
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pfd->events &= ~POLLRDHUP;
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poll_check_ok(pop);
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if (pfd->events)
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/* Another event cares about that fd. */
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return (0);
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/* Okay, so we aren't interested in that fd anymore. */
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idx->idxplus1 = 0;
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--pop->nfds;
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if (i != pop->nfds) {
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/*
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* Shift the last pollfd down into the now-unoccupied
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* position.
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*/
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memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
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sizeof(struct pollfd));
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idx = evmap_io_get_fdinfo_(&base->io, pop->event_set[i].fd);
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EVUTIL_ASSERT(idx);
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EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1);
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idx->idxplus1 = i + 1;
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}
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poll_check_ok(pop);
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return (0);
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}
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static void
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poll_dealloc(struct event_base *base)
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{
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struct pollop *pop = base->evbase;
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evsig_dealloc_(base);
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if (pop->event_set)
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mm_free(pop->event_set);
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if (pop->event_set_copy)
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mm_free(pop->event_set_copy);
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memset(pop, 0, sizeof(struct pollop));
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mm_free(pop);
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}
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#endif /* EVENT__HAVE_POLL */
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