365 lines
8.9 KiB
C
365 lines
8.9 KiB
C
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/* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
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/*
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* Copyright 2000-2002 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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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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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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#ifdef HAVE_SYS_SELECT_H
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#include <sys/select.h>
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#endif
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#include <sys/queue.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 "evutil.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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#ifndef howmany
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#define howmany(x, y) (((x)+((y)-1))/(y))
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#endif
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#ifndef _EVENT_HAVE_FD_MASK
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/* This type is mandatory, but Android doesn't define it. */
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#undef NFDBITS
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#define NFDBITS (sizeof(long)*8)
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typedef unsigned long fd_mask;
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#endif
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struct selectop {
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int event_fds; /* Highest fd in fd set */
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int event_fdsz;
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fd_set *event_readset_in;
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fd_set *event_writeset_in;
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fd_set *event_readset_out;
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fd_set *event_writeset_out;
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struct event **event_r_by_fd;
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struct event **event_w_by_fd;
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};
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static void *select_init (struct event_base *);
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static int select_add (void *, struct event *);
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static int select_del (void *, struct event *);
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static int select_dispatch (struct event_base *, void *, struct timeval *);
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static void select_dealloc (struct event_base *, void *);
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const struct eventop selectops = {
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"select",
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select_init,
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select_add,
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select_del,
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select_dispatch,
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select_dealloc,
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0
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};
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static int select_resize(struct selectop *sop, int fdsz);
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static void *
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select_init(struct event_base *base)
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{
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struct selectop *sop;
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/* Disable select when this environment variable is set */
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if (evutil_getenv("EVENT_NOSELECT"))
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return (NULL);
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if (!(sop = calloc(1, sizeof(struct selectop))))
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return (NULL);
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select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask));
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evsignal_init(base);
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return (sop);
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}
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#ifdef CHECK_INVARIANTS
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static void
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check_selectop(struct selectop *sop)
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{
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int i;
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for (i = 0; i <= sop->event_fds; ++i) {
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if (FD_ISSET(i, sop->event_readset_in)) {
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assert(sop->event_r_by_fd[i]);
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assert(sop->event_r_by_fd[i]->ev_events & EV_READ);
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assert(sop->event_r_by_fd[i]->ev_fd == i);
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} else {
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assert(! sop->event_r_by_fd[i]);
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}
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if (FD_ISSET(i, sop->event_writeset_in)) {
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assert(sop->event_w_by_fd[i]);
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assert(sop->event_w_by_fd[i]->ev_events & EV_WRITE);
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assert(sop->event_w_by_fd[i]->ev_fd == i);
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} else {
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assert(! sop->event_w_by_fd[i]);
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}
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}
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}
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#else
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#define check_selectop(sop) do { (void) sop; } while (0)
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#endif
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static int
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select_dispatch(struct event_base *base, void *arg, struct timeval *tv)
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{
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int res, i, j;
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struct selectop *sop = arg;
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check_selectop(sop);
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memcpy(sop->event_readset_out, sop->event_readset_in,
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sop->event_fdsz);
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memcpy(sop->event_writeset_out, sop->event_writeset_in,
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sop->event_fdsz);
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res = select(sop->event_fds + 1, sop->event_readset_out,
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sop->event_writeset_out, NULL, tv);
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check_selectop(sop);
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if (res == -1) {
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if (errno != EINTR) {
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event_warn("select");
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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: select reports %d", __func__, res));
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check_selectop(sop);
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i = random() % (sop->event_fds+1);
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for (j = 0; j <= sop->event_fds; ++j) {
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struct event *r_ev = NULL, *w_ev = NULL;
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if (++i >= sop->event_fds+1)
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i = 0;
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res = 0;
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if (FD_ISSET(i, sop->event_readset_out)) {
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r_ev = sop->event_r_by_fd[i];
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res |= EV_READ;
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}
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if (FD_ISSET(i, sop->event_writeset_out)) {
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w_ev = sop->event_w_by_fd[i];
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res |= EV_WRITE;
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}
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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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check_selectop(sop);
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return (0);
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}
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static int
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select_resize(struct selectop *sop, int fdsz)
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{
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int n_events, n_events_old;
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fd_set *readset_in = NULL;
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fd_set *writeset_in = NULL;
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fd_set *readset_out = NULL;
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fd_set *writeset_out = NULL;
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struct event **r_by_fd = NULL;
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struct event **w_by_fd = NULL;
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n_events = (fdsz/sizeof(fd_mask)) * NFDBITS;
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n_events_old = (sop->event_fdsz/sizeof(fd_mask)) * NFDBITS;
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if (sop->event_readset_in)
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check_selectop(sop);
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if ((readset_in = realloc(sop->event_readset_in, fdsz)) == NULL)
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goto error;
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sop->event_readset_in = readset_in;
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if ((readset_out = realloc(sop->event_readset_out, fdsz)) == NULL)
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goto error;
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sop->event_readset_out = readset_out;
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if ((writeset_in = realloc(sop->event_writeset_in, fdsz)) == NULL)
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goto error;
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sop->event_writeset_in = writeset_in;
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if ((writeset_out = realloc(sop->event_writeset_out, fdsz)) == NULL)
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goto error;
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sop->event_writeset_out = writeset_out;
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if ((r_by_fd = realloc(sop->event_r_by_fd,
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n_events*sizeof(struct event*))) == NULL)
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goto error;
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sop->event_r_by_fd = r_by_fd;
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if ((w_by_fd = realloc(sop->event_w_by_fd,
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n_events * sizeof(struct event*))) == NULL)
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goto error;
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sop->event_w_by_fd = w_by_fd;
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memset((char *)sop->event_readset_in + sop->event_fdsz, 0,
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fdsz - sop->event_fdsz);
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memset((char *)sop->event_writeset_in + sop->event_fdsz, 0,
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fdsz - sop->event_fdsz);
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memset(sop->event_r_by_fd + n_events_old, 0,
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(n_events-n_events_old) * sizeof(struct event*));
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memset(sop->event_w_by_fd + n_events_old, 0,
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(n_events-n_events_old) * sizeof(struct event*));
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sop->event_fdsz = fdsz;
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check_selectop(sop);
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return (0);
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error:
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event_warn("malloc");
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return (-1);
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}
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static int
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select_add(void *arg, struct event *ev)
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{
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struct selectop *sop = arg;
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if (ev->ev_events & EV_SIGNAL)
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return (evsignal_add(ev));
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check_selectop(sop);
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/*
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* Keep track of the highest fd, so that we can calculate the size
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* of the fd_sets for select(2)
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*/
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if (sop->event_fds < ev->ev_fd) {
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int fdsz = sop->event_fdsz;
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if (fdsz < sizeof(fd_mask))
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fdsz = sizeof(fd_mask);
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while (fdsz <
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(howmany(ev->ev_fd + 1, NFDBITS) * sizeof(fd_mask)))
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fdsz *= 2;
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if (fdsz != sop->event_fdsz) {
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if (select_resize(sop, fdsz)) {
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check_selectop(sop);
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return (-1);
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}
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}
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sop->event_fds = ev->ev_fd;
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}
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if (ev->ev_events & EV_READ) {
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FD_SET(ev->ev_fd, sop->event_readset_in);
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sop->event_r_by_fd[ev->ev_fd] = ev;
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}
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if (ev->ev_events & EV_WRITE) {
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FD_SET(ev->ev_fd, sop->event_writeset_in);
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sop->event_w_by_fd[ev->ev_fd] = ev;
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}
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check_selectop(sop);
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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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select_del(void *arg, struct event *ev)
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{
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struct selectop *sop = arg;
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check_selectop(sop);
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if (ev->ev_events & EV_SIGNAL)
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return (evsignal_del(ev));
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if (sop->event_fds < ev->ev_fd) {
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check_selectop(sop);
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return (0);
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}
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if (ev->ev_events & EV_READ) {
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FD_CLR(ev->ev_fd, sop->event_readset_in);
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sop->event_r_by_fd[ev->ev_fd] = NULL;
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}
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if (ev->ev_events & EV_WRITE) {
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FD_CLR(ev->ev_fd, sop->event_writeset_in);
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sop->event_w_by_fd[ev->ev_fd] = NULL;
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}
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check_selectop(sop);
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return (0);
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}
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static void
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select_dealloc(struct event_base *base, void *arg)
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{
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struct selectop *sop = arg;
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evsignal_dealloc(base);
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if (sop->event_readset_in)
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free(sop->event_readset_in);
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if (sop->event_writeset_in)
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free(sop->event_writeset_in);
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if (sop->event_readset_out)
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free(sop->event_readset_out);
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if (sop->event_writeset_out)
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free(sop->event_writeset_out);
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if (sop->event_r_by_fd)
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free(sop->event_r_by_fd);
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if (sop->event_w_by_fd)
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free(sop->event_w_by_fd);
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memset(sop, 0, sizeof(struct selectop));
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free(sop);
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}
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