379 lines
9.0 KiB
C
379 lines
9.0 KiB
C
/* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
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/*
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* Copyright 2000-2003 Niels Provos <provos@citi.umich.edu>
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* All rights reserved.
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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 "config.h"
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#include <sys/types.h>
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#else
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#include <sys/_libevent_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 <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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#ifdef CHECK_INVARIANTS
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#include <assert.h>
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#endif
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#include "event.h"
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#include "event-internal.h"
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#include "evsignal.h"
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#include "log.h"
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struct pollop {
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int event_count; /* Highest number alloc */
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int nfds; /* Size of event_* */
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int fd_count; /* Size of idxplus1_by_fd */
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struct pollfd *event_set;
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struct event **event_r_back;
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struct event **event_w_back;
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int *idxplus1_by_fd; /* Index into event_set by fd; we add 1 so
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* that 0 (which is easy to memset) can mean
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* "no entry." */
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};
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static void *poll_init (struct event_base *);
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static int poll_add (void *, struct event *);
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static int poll_del (void *, struct event *);
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static int poll_dispatch (struct event_base *, void *, struct timeval *);
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static void poll_dealloc (struct event_base *, void *);
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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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0
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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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/* Disable poll when this environment variable is set */
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if (evutil_getenv("EVENT_NOPOLL"))
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return (NULL);
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if (!(pollop = calloc(1, sizeof(struct pollop))))
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return (NULL);
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evsignal_init(base);
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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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assert(pop->event_set[idx].fd == i);
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if (pop->event_set[idx].events & POLLIN) {
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ev = pop->event_r_back[idx];
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assert(ev);
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assert(ev->ev_events & EV_READ);
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assert(ev->ev_fd == i);
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}
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if (pop->event_set[idx].events & POLLOUT) {
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ev = pop->event_w_back[idx];
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assert(ev);
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assert(ev->ev_events & EV_WRITE);
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assert(ev->ev_fd == i);
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}
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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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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, void *arg, struct timeval *tv)
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{
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int res, i, j, msec = -1, nfds;
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struct pollop *pop = arg;
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poll_check_ok(pop);
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if (tv != NULL)
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msec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
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nfds = pop->nfds;
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res = poll(pop->event_set, nfds, msec);
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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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evsignal_process(base);
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return (0);
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} else if (base->sig.evsignal_caught) {
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evsignal_process(base);
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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 = random() % nfds;
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for (j = 0; j < nfds; j++) {
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struct event *r_ev = NULL, *w_ev = NULL;
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int what;
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if (++i == nfds)
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i = 0;
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what = pop->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))
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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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r_ev = pop->event_r_back[i];
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}
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if (what & POLLOUT) {
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res |= EV_WRITE;
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w_ev = pop->event_w_back[i];
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}
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if (res == 0)
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continue;
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if (r_ev && (res & r_ev->ev_events)) {
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event_active(r_ev, res & r_ev->ev_events, 1);
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}
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if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
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event_active(w_ev, res & w_ev->ev_events, 1);
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}
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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(void *arg, struct event *ev)
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{
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struct pollop *pop = arg;
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struct pollfd *pfd = NULL;
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int i;
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if (ev->ev_events & EV_SIGNAL)
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return (evsignal_add(ev));
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if (!(ev->ev_events & (EV_READ|EV_WRITE)))
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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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struct event **tmp_event_r_back;
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struct event **tmp_event_w_back;
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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 = 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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tmp_event_r_back = realloc(pop->event_r_back,
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tmp_event_count * sizeof(struct event *));
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if (tmp_event_r_back == NULL) {
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/* event_set overallocated; that's okay. */
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event_warn("realloc");
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return (-1);
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}
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pop->event_r_back = tmp_event_r_back;
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tmp_event_w_back = realloc(pop->event_w_back,
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tmp_event_count * sizeof(struct event *));
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if (tmp_event_w_back == NULL) {
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/* event_set and event_r_back overallocated; that's
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* okay. */
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event_warn("realloc");
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return (-1);
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}
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pop->event_w_back = tmp_event_w_back;
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pop->event_count = tmp_event_count;
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}
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if (ev->ev_fd >= pop->fd_count) {
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int *tmp_idxplus1_by_fd;
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int new_count;
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if (pop->fd_count < 32)
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new_count = 32;
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else
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new_count = pop->fd_count * 2;
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while (new_count <= ev->ev_fd)
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new_count *= 2;
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tmp_idxplus1_by_fd =
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realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
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if (tmp_idxplus1_by_fd == NULL) {
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event_warn("realloc");
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return (-1);
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}
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pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
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memset(pop->idxplus1_by_fd + pop->fd_count,
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0, sizeof(int)*(new_count - pop->fd_count));
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pop->fd_count = new_count;
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}
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i = pop->idxplus1_by_fd[ev->ev_fd] - 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 = ev->ev_fd;
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pop->event_w_back[i] = pop->event_r_back[i] = NULL;
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pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
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}
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pfd->revents = 0;
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if (ev->ev_events & EV_WRITE) {
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pfd->events |= POLLOUT;
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pop->event_w_back[i] = ev;
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}
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if (ev->ev_events & EV_READ) {
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pfd->events |= POLLIN;
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pop->event_r_back[i] = ev;
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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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/*
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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(void *arg, struct event *ev)
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{
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struct pollop *pop = arg;
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struct pollfd *pfd = NULL;
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int i;
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if (ev->ev_events & EV_SIGNAL)
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return (evsignal_del(ev));
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if (!(ev->ev_events & (EV_READ|EV_WRITE)))
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return (0);
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poll_check_ok(pop);
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i = pop->idxplus1_by_fd[ev->ev_fd] - 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 (ev->ev_events & EV_READ) {
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pfd->events &= ~POLLIN;
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pop->event_r_back[i] = NULL;
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}
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if (ev->ev_events & EV_WRITE) {
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pfd->events &= ~POLLOUT;
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pop->event_w_back[i] = NULL;
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}
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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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pop->idxplus1_by_fd[ev->ev_fd] = 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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pop->event_r_back[i] = pop->event_r_back[pop->nfds];
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pop->event_w_back[i] = pop->event_w_back[pop->nfds];
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pop->idxplus1_by_fd[pop->event_set[i].fd] = 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, void *arg)
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{
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struct pollop *pop = arg;
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evsignal_dealloc(base);
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if (pop->event_set)
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free(pop->event_set);
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if (pop->event_r_back)
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free(pop->event_r_back);
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if (pop->event_w_back)
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free(pop->event_w_back);
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if (pop->idxplus1_by_fd)
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free(pop->idxplus1_by_fd);
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memset(pop, 0, sizeof(struct pollop));
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free(pop);
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}
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