Repo created

TMessagesProj/jni/voip/webrtc/base/third_party/libevent/signal.c

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+/*	$OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/
+
+/*
+ * Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <winsock2.h>
+#include <windows.h>
+#undef WIN32_LEAN_AND_MEAN
+#endif
+#include <sys/types.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#include <sys/queue.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <errno.h>
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+#include <assert.h>
+
+#include "event.h"
+#include "event-internal.h"
+#include "evsignal.h"
+#include "evutil.h"
+#include "log.h"
+
+struct event_base *evsignal_base = NULL;
+
+static void evsignal_handler(int sig);
+
+#ifdef WIN32
+#define error_is_eagain(err)			\
+	((err) == EAGAIN || (err) == WSAEWOULDBLOCK)
+#else
+#define error_is_eagain(err) ((err) == EAGAIN)
+#endif
+
+/* Callback for when the signal handler write a byte to our signaling socket */
+static void
+evsignal_cb(int fd, short what, void *arg)
+{
+	static char signals[1];
+#ifdef WIN32
+	SSIZE_T n;
+#else
+	ssize_t n;
+#endif
+
+	n = recv(fd, signals, sizeof(signals), 0);
+	if (n == -1) {
+		int err = EVUTIL_SOCKET_ERROR();
+		if (! error_is_eagain(err))
+			event_err(1, "%s: read", __func__);
+	}
+}
+
+#ifdef HAVE_SETFD
+#define FD_CLOSEONEXEC(x) do { \
+        if (fcntl(x, F_SETFD, 1) == -1) \
+                event_warn("fcntl(%d, F_SETFD)", x); \
+} while (0)
+#else
+#define FD_CLOSEONEXEC(x)
+#endif
+
+int
+evsignal_init(struct event_base *base)
+{
+	int i;
+
+	/* 
+	 * Our signal handler is going to write to one end of the socket
+	 * pair to wake up our event loop.  The event loop then scans for
+	 * signals that got delivered.
+	 */
+	if (evutil_socketpair(
+		    AF_UNIX, SOCK_STREAM, 0, base->sig.ev_signal_pair) == -1) {
+#ifdef WIN32
+		/* Make this nonfatal on win32, where sometimes people
+		   have localhost firewalled. */
+		event_warn("%s: socketpair", __func__);
+#else
+		event_err(1, "%s: socketpair", __func__);
+#endif
+		return -1;
+	}
+
+	FD_CLOSEONEXEC(base->sig.ev_signal_pair[0]);
+	FD_CLOSEONEXEC(base->sig.ev_signal_pair[1]);
+	base->sig.sh_old = NULL;
+	base->sig.sh_old_max = 0;
+	base->sig.evsignal_caught = 0;
+	memset(&base->sig.evsigcaught, 0, sizeof(sig_atomic_t)*NSIG);
+	/* initialize the queues for all events */
+	for (i = 0; i < NSIG; ++i)
+		TAILQ_INIT(&base->sig.evsigevents[i]);
+
+        evutil_make_socket_nonblocking(base->sig.ev_signal_pair[0]);
+        evutil_make_socket_nonblocking(base->sig.ev_signal_pair[1]);
+
+	event_set(&base->sig.ev_signal, base->sig.ev_signal_pair[1],
+		EV_READ | EV_PERSIST, evsignal_cb, &base->sig.ev_signal);
+	base->sig.ev_signal.ev_base = base;
+	base->sig.ev_signal.ev_flags |= EVLIST_INTERNAL;
+
+	return 0;
+}
+
+/* Helper: set the signal handler for evsignal to handler in base, so that
+ * we can restore the original handler when we clear the current one. */
+int
+_evsignal_set_handler(struct event_base *base,
+		      int evsignal, void (*handler)(int))
+{
+#ifdef HAVE_SIGACTION
+	struct sigaction sa;
+#else
+	ev_sighandler_t sh;
+#endif
+	struct evsignal_info *sig = &base->sig;
+	void *p;
+
+	/*
+	 * resize saved signal handler array up to the highest signal number.
+	 * a dynamic array is used to keep footprint on the low side.
+	 */
+	if (evsignal >= sig->sh_old_max) {
+		int new_max = evsignal + 1;
+		event_debug(("%s: evsignal (%d) >= sh_old_max (%d), resizing",
+			    __func__, evsignal, sig->sh_old_max));
+		p = realloc(sig->sh_old, new_max * sizeof(*sig->sh_old));
+		if (p == NULL) {
+			event_warn("realloc");
+			return (-1);
+		}
+
+		memset((char *)p + sig->sh_old_max * sizeof(*sig->sh_old),
+		    0, (new_max - sig->sh_old_max) * sizeof(*sig->sh_old));
+
+		sig->sh_old_max = new_max;
+		sig->sh_old = p;
+	}
+
+	/* allocate space for previous handler out of dynamic array */
+	sig->sh_old[evsignal] = malloc(sizeof *sig->sh_old[evsignal]);
+	if (sig->sh_old[evsignal] == NULL) {
+		event_warn("malloc");
+		return (-1);
+	}
+
+	/* save previous handler and setup new handler */
+#ifdef HAVE_SIGACTION
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = handler;
+	sa.sa_flags |= SA_RESTART;
+	sigfillset(&sa.sa_mask);
+
+	if (sigaction(evsignal, &sa, sig->sh_old[evsignal]) == -1) {
+		event_warn("sigaction");
+		free(sig->sh_old[evsignal]);
+		sig->sh_old[evsignal] = NULL;
+		return (-1);
+	}
+#else
+	if ((sh = signal(evsignal, handler)) == SIG_ERR) {
+		event_warn("signal");
+		free(sig->sh_old[evsignal]);
+		sig->sh_old[evsignal] = NULL;
+		return (-1);
+	}
+	*sig->sh_old[evsignal] = sh;
+#endif
+
+	return (0);
+}
+
+int
+evsignal_add(struct event *ev)
+{
+	int evsignal;
+	struct event_base *base = ev->ev_base;
+	struct evsignal_info *sig = &ev->ev_base->sig;
+
+	if (ev->ev_events & (EV_READ|EV_WRITE))
+		event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
+	evsignal = EVENT_SIGNAL(ev);
+	assert(evsignal >= 0 && evsignal < NSIG);
+	if (TAILQ_EMPTY(&sig->evsigevents[evsignal])) {
+		event_debug(("%s: %p: changing signal handler", __func__, ev));
+		if (_evsignal_set_handler(
+			    base, evsignal, evsignal_handler) == -1)
+			return (-1);
+
+		/* catch signals if they happen quickly */
+		evsignal_base = base;
+
+		if (!sig->ev_signal_added) {
+			if (event_add(&sig->ev_signal, NULL))
+				return (-1);
+			sig->ev_signal_added = 1;
+		}
+	}
+
+	/* multiple events may listen to the same signal */
+	TAILQ_INSERT_TAIL(&sig->evsigevents[evsignal], ev, ev_signal_next);
+
+	return (0);
+}
+
+int
+_evsignal_restore_handler(struct event_base *base, int evsignal)
+{
+	int ret = 0;
+	struct evsignal_info *sig = &base->sig;
+#ifdef HAVE_SIGACTION
+	struct sigaction *sh;
+#else
+	ev_sighandler_t *sh;
+#endif
+
+	/* restore previous handler */
+	sh = sig->sh_old[evsignal];
+	sig->sh_old[evsignal] = NULL;
+#ifdef HAVE_SIGACTION
+	if (sigaction(evsignal, sh, NULL) == -1) {
+		event_warn("sigaction");
+		ret = -1;
+	}
+#else
+	if (signal(evsignal, *sh) == SIG_ERR) {
+		event_warn("signal");
+		ret = -1;
+	}
+#endif
+	free(sh);
+
+	return ret;
+}
+
+int
+evsignal_del(struct event *ev)
+{
+	struct event_base *base = ev->ev_base;
+	struct evsignal_info *sig = &base->sig;
+	int evsignal = EVENT_SIGNAL(ev);
+
+	assert(evsignal >= 0 && evsignal < NSIG);
+
+	/* multiple events may listen to the same signal */
+	TAILQ_REMOVE(&sig->evsigevents[evsignal], ev, ev_signal_next);
+
+	if (!TAILQ_EMPTY(&sig->evsigevents[evsignal]))
+		return (0);
+
+	event_debug(("%s: %p: restoring signal handler", __func__, ev));
+
+	return (_evsignal_restore_handler(ev->ev_base, EVENT_SIGNAL(ev)));
+}
+
+static void
+evsignal_handler(int sig)
+{
+	int save_errno = errno;
+
+	if (evsignal_base == NULL) {
+		event_warn(
+			"%s: received signal %d, but have no base configured",
+			__func__, sig);
+		return;
+	}
+
+	evsignal_base->sig.evsigcaught[sig]++;
+	evsignal_base->sig.evsignal_caught = 1;
+
+#ifndef HAVE_SIGACTION
+	signal(sig, evsignal_handler);
+#endif
+
+	/* Wake up our notification mechanism */
+	send(evsignal_base->sig.ev_signal_pair[0], "a", 1, 0);
+	errno = save_errno;
+}
+
+void
+evsignal_process(struct event_base *base)
+{
+	struct evsignal_info *sig = &base->sig;
+	struct event *ev, *next_ev;
+	sig_atomic_t ncalls;
+	int i;
+	
+	base->sig.evsignal_caught = 0;
+	for (i = 1; i < NSIG; ++i) {
+		ncalls = sig->evsigcaught[i];
+		if (ncalls == 0)
+			continue;
+		sig->evsigcaught[i] -= ncalls;
+
+		for (ev = TAILQ_FIRST(&sig->evsigevents[i]);
+		    ev != NULL; ev = next_ev) {
+			next_ev = TAILQ_NEXT(ev, ev_signal_next);
+			if (!(ev->ev_events & EV_PERSIST))
+				event_del(ev);
+			event_active(ev, EV_SIGNAL, ncalls);
+		}
+
+	}
+}
+
+void
+evsignal_dealloc(struct event_base *base)
+{
+	int i = 0;
+	if (base->sig.ev_signal_added) {
+		event_del(&base->sig.ev_signal);
+		base->sig.ev_signal_added = 0;
+	}
+	for (i = 0; i < NSIG; ++i) {
+		if (i < base->sig.sh_old_max && base->sig.sh_old[i] != NULL)
+			_evsignal_restore_handler(base, i);
+	}
+
+	if (base->sig.ev_signal_pair[0] != -1) {
+		EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
+		base->sig.ev_signal_pair[0] = -1;
+	}
+	if (base->sig.ev_signal_pair[1] != -1) {
+		EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[1]);
+		base->sig.ev_signal_pair[1] = -1;
+	}
+	base->sig.sh_old_max = 0;
+
+	/* per index frees are handled in evsig_del() */
+	if (base->sig.sh_old) {
+		free(base->sig.sh_old);
+		base->sig.sh_old = NULL;
+	}
+}