358 lines
9.0 KiB
C
358 lines
9.0 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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#ifdef WIN32
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#define WIN32_LEAN_AND_MEAN
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#include <winsock2.h>
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#include <windows.h>
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#undef WIN32_LEAN_AND_MEAN
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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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#endif
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#include <sys/queue.h>
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#ifdef HAVE_SYS_SOCKET_H
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#include <sys/socket.h>
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#endif
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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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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <errno.h>
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#include <assert.h>
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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 "evutil.h"
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#include "log.h"
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struct event_base *evsignal_base = NULL;
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static void evsignal_handler(int sig);
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/* Callback for when the signal handler write a byte to our signaling socket */
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static void
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evsignal_cb(int fd, short what, void *arg)
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{
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static char signals[1];
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#ifdef WIN32
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SSIZE_T n;
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#else
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ssize_t n;
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#endif
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n = recv(fd, signals, sizeof(signals), 0);
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if (n == -1)
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event_err(1, "%s: read", __func__);
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}
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#ifdef HAVE_SETFD
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#define FD_CLOSEONEXEC(x) do { \
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if (fcntl(x, F_SETFD, 1) == -1) \
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event_warn("fcntl(%d, F_SETFD)", x); \
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} while (0)
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#else
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#define FD_CLOSEONEXEC(x)
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#endif
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int
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evsignal_init(struct event_base *base)
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{
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int i;
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/*
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* Our signal handler is going to write to one end of the socket
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* pair to wake up our event loop. The event loop then scans for
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* signals that got delivered.
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*/
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if (evutil_socketpair(
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AF_UNIX, SOCK_STREAM, 0, base->sig.ev_signal_pair) == -1) {
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#ifdef WIN32
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/* Make this nonfatal on win32, where sometimes people
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have localhost firewalled. */
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event_warn("%s: socketpair", __func__);
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#else
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event_err(1, "%s: socketpair", __func__);
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#endif
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return -1;
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}
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FD_CLOSEONEXEC(base->sig.ev_signal_pair[0]);
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FD_CLOSEONEXEC(base->sig.ev_signal_pair[1]);
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base->sig.sh_old = NULL;
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base->sig.sh_old_max = 0;
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base->sig.evsignal_caught = 0;
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memset(&base->sig.evsigcaught, 0, sizeof(sig_atomic_t)*NSIG);
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/* initialize the queues for all events */
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for (i = 0; i < NSIG; ++i)
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TAILQ_INIT(&base->sig.evsigevents[i]);
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evutil_make_socket_nonblocking(base->sig.ev_signal_pair[0]);
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event_set(&base->sig.ev_signal, base->sig.ev_signal_pair[1],
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EV_READ | EV_PERSIST, evsignal_cb, &base->sig.ev_signal);
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base->sig.ev_signal.ev_base = base;
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base->sig.ev_signal.ev_flags |= EVLIST_INTERNAL;
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return 0;
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}
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/* Helper: set the signal handler for evsignal to handler in base, so that
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* we can restore the original handler when we clear the current one. */
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int
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_evsignal_set_handler(struct event_base *base,
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int evsignal, void (*handler)(int))
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{
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#ifdef HAVE_SIGACTION
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struct sigaction sa;
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#else
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ev_sighandler_t sh;
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#endif
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struct evsignal_info *sig = &base->sig;
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void *p;
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/*
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* resize saved signal handler array up to the highest signal number.
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* a dynamic array is used to keep footprint on the low side.
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*/
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if (evsignal >= sig->sh_old_max) {
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int new_max = evsignal + 1;
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event_debug(("%s: evsignal (%d) >= sh_old_max (%d), resizing",
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__func__, evsignal, sig->sh_old_max));
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p = realloc(sig->sh_old, new_max * sizeof(*sig->sh_old));
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if (p == NULL) {
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event_warn("realloc");
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return (-1);
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}
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memset((char *)p + sig->sh_old_max * sizeof(*sig->sh_old),
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0, (new_max - sig->sh_old_max) * sizeof(*sig->sh_old));
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sig->sh_old_max = new_max;
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sig->sh_old = p;
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}
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/* allocate space for previous handler out of dynamic array */
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sig->sh_old[evsignal] = malloc(sizeof *sig->sh_old[evsignal]);
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if (sig->sh_old[evsignal] == NULL) {
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event_warn("malloc");
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return (-1);
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}
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/* save previous handler and setup new handler */
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#ifdef HAVE_SIGACTION
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memset(&sa, 0, sizeof(sa));
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sa.sa_handler = handler;
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sa.sa_flags |= SA_RESTART;
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sigfillset(&sa.sa_mask);
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if (sigaction(evsignal, &sa, sig->sh_old[evsignal]) == -1) {
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event_warn("sigaction");
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free(sig->sh_old[evsignal]);
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return (-1);
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}
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#else
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if ((sh = signal(evsignal, handler)) == SIG_ERR) {
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event_warn("signal");
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free(sig->sh_old[evsignal]);
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return (-1);
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}
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*sig->sh_old[evsignal] = sh;
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#endif
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return (0);
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}
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int
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evsignal_add(struct event *ev)
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{
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int evsignal;
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struct event_base *base = ev->ev_base;
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struct evsignal_info *sig = &ev->ev_base->sig;
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if (ev->ev_events & (EV_READ|EV_WRITE))
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event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
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evsignal = EVENT_SIGNAL(ev);
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assert(evsignal >= 0 && evsignal < NSIG);
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if (TAILQ_EMPTY(&sig->evsigevents[evsignal])) {
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event_debug(("%s: %p: changing signal handler", __func__, ev));
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if (_evsignal_set_handler(
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base, evsignal, evsignal_handler) == -1)
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return (-1);
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/* catch signals if they happen quickly */
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evsignal_base = base;
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if (!sig->ev_signal_added) {
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if (event_add(&sig->ev_signal, NULL))
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return (-1);
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sig->ev_signal_added = 1;
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}
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}
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/* multiple events may listen to the same signal */
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TAILQ_INSERT_TAIL(&sig->evsigevents[evsignal], ev, ev_signal_next);
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return (0);
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}
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int
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_evsignal_restore_handler(struct event_base *base, int evsignal)
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{
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int ret = 0;
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struct evsignal_info *sig = &base->sig;
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#ifdef HAVE_SIGACTION
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struct sigaction *sh;
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#else
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ev_sighandler_t *sh;
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#endif
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/* restore previous handler */
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sh = sig->sh_old[evsignal];
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sig->sh_old[evsignal] = NULL;
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#ifdef HAVE_SIGACTION
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if (sigaction(evsignal, sh, NULL) == -1) {
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event_warn("sigaction");
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ret = -1;
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}
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#else
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if (signal(evsignal, *sh) == SIG_ERR) {
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event_warn("signal");
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ret = -1;
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}
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#endif
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free(sh);
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return ret;
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}
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int
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evsignal_del(struct event *ev)
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{
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struct event_base *base = ev->ev_base;
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struct evsignal_info *sig = &base->sig;
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int evsignal = EVENT_SIGNAL(ev);
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assert(evsignal >= 0 && evsignal < NSIG);
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/* multiple events may listen to the same signal */
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TAILQ_REMOVE(&sig->evsigevents[evsignal], ev, ev_signal_next);
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if (!TAILQ_EMPTY(&sig->evsigevents[evsignal]))
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return (0);
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event_debug(("%s: %p: restoring signal handler", __func__, ev));
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return (_evsignal_restore_handler(ev->ev_base, EVENT_SIGNAL(ev)));
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}
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static void
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evsignal_handler(int sig)
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{
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int save_errno = errno;
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if (evsignal_base == NULL) {
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event_warn(
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"%s: received signal %d, but have no base configured",
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__func__, sig);
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return;
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}
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evsignal_base->sig.evsigcaught[sig]++;
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evsignal_base->sig.evsignal_caught = 1;
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#ifndef HAVE_SIGACTION
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signal(sig, evsignal_handler);
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#endif
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/* Wake up our notification mechanism */
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send(evsignal_base->sig.ev_signal_pair[0], "a", 1, 0);
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errno = save_errno;
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}
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void
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evsignal_process(struct event_base *base)
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{
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struct evsignal_info *sig = &base->sig;
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struct event *ev, *next_ev;
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sig_atomic_t ncalls;
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int i;
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base->sig.evsignal_caught = 0;
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for (i = 1; i < NSIG; ++i) {
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ncalls = sig->evsigcaught[i];
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if (ncalls == 0)
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continue;
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sig->evsigcaught[i] -= ncalls;
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for (ev = TAILQ_FIRST(&sig->evsigevents[i]);
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ev != NULL; ev = next_ev) {
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next_ev = TAILQ_NEXT(ev, ev_signal_next);
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if (!(ev->ev_events & EV_PERSIST))
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event_del(ev);
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event_active(ev, EV_SIGNAL, ncalls);
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}
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}
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}
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void
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evsignal_dealloc(struct event_base *base)
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{
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int i = 0;
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if (base->sig.ev_signal_added) {
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event_del(&base->sig.ev_signal);
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base->sig.ev_signal_added = 0;
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}
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for (i = 0; i < NSIG; ++i) {
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if (i < base->sig.sh_old_max && base->sig.sh_old[i] != NULL)
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_evsignal_restore_handler(base, i);
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}
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EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
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base->sig.ev_signal_pair[0] = -1;
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EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[1]);
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base->sig.ev_signal_pair[1] = -1;
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base->sig.sh_old_max = 0;
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/* per index frees are handled in evsignal_del() */
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free(base->sig.sh_old);
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}
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