The Tor Browser: ipc/chromium/src/third_party/libevent/signal.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/signal.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/signal.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*	$OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $	*/
 /*
  * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
  * Copyright 2007-2012 Niels Provos and Nick Mathewson
  *
  * 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 "event2/event-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 _EVENT_HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif
 #include <sys/queue.h>
 #ifdef _EVENT_HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #ifdef _EVENT_HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 #include <errno.h>
 #ifdef _EVENT_HAVE_FCNTL_H
 #include <fcntl.h>
 #endif
 #include "event2/event.h"
 #include "event2/event_struct.h"
 #include "event-internal.h"
 #include "event2/util.h"
 #include "evsignal-internal.h"
 #include "log-internal.h"
 #include "evmap-internal.h"
 #include "evthread-internal.h"
 /*
   signal.c
   This is the signal-handling implementation we use for backends that don't
   have a better way to do signal handling.  It uses sigaction() or signal()
   to set a signal handler, and a socket pair to tell the event base when
   Note that I said "the event base" : only one event base can be set up to use
   this at a time.  For historical reasons and backward compatibility, if you
   add an event for a signal to event_base A, then add an event for a signal
   (any signal!) to event_base B, event_base B will get informed about the
   signal, but event_base A won't.
   It would be neat to change this behavior in some future version of Libevent.
   kqueue already does something far more sensible.  We can make all backends
   on Linux do a reasonable thing using signalfd.
 */
 #ifndef WIN32
 /* Windows wants us to call our signal handlers as __cdecl.  Nobody else
  * expects you to do anything crazy like this. */
 #define __cdecl
 #endif
 static int evsig_add(struct event_base *, evutil_socket_t, short, short, void *);
 static int evsig_del(struct event_base *, evutil_socket_t, short, short, void *);
 static const struct eventop evsigops = {
 	"signal",
 	NULL,
 	evsig_add,
 	evsig_del,
 	NULL,
 	NULL,
 , 0, 0
 };
 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
 /* Lock for evsig_base and evsig_base_n_signals_added fields. */
 static void *evsig_base_lock = NULL;
 #endif
 /* The event base that's currently getting informed about signals. */
 static struct event_base *evsig_base = NULL;
 /* A copy of evsig_base->sigev_n_signals_added. */
 static int evsig_base_n_signals_added = 0;
 static evutil_socket_t evsig_base_fd = -1;
 static void __cdecl evsig_handler(int sig);
 #define EVSIGBASE_LOCK() EVLOCK_LOCK(evsig_base_lock, 0)
 #define EVSIGBASE_UNLOCK() EVLOCK_UNLOCK(evsig_base_lock, 0)
 void
 evsig_set_base(struct event_base *base)
 {
 	EVSIGBASE_LOCK();
 	evsig_base = base;
 	evsig_base_n_signals_added = base->sig.ev_n_signals_added;
 	evsig_base_fd = base->sig.ev_signal_pair[0];
 	EVSIGBASE_UNLOCK();
 }
 /* Callback for when the signal handler write a byte to our signaling socket */
 static void
 evsig_cb(evutil_socket_t fd, short what, void *arg)
 {
 	static char signals[1024];
 	ev_ssize_t n;
 	int i;
 	int ncaught[NSIG];
 	struct event_base *base;
 	base = arg;
 	memset(&ncaught, 0, sizeof(ncaught));
 	while (1) {
 		n = recv(fd, signals, sizeof(signals), 0);
 		if (n == -1) {
 			int err = evutil_socket_geterror(fd);
 			if (! EVUTIL_ERR_RW_RETRIABLE(err))
 				event_sock_err(1, fd, "%s: recv", __func__);
 			break;
 		} else if (n == 0) {
 			/* XXX warn? */
 			break;
 		}
 		for (i = 0; i < n; ++i) {
 			ev_uint8_t sig = signals[i];
 			if (sig < NSIG)
 				ncaught[sig]++;
 		}
 	}
 	EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 	for (i = 0; i < NSIG; ++i) {
 		if (ncaught[i])
 			evmap_signal_active(base, i, ncaught[i]);
 	}
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 }
 int
 evsig_init(struct event_base *base)
 {
 	/*
 	 * 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_sock_warn(-1, "%s: socketpair", __func__);
 #else
 		event_sock_err(1, -1, "%s: socketpair", __func__);
 #endif
 		return -1;
 	}
 	evutil_make_socket_closeonexec(base->sig.ev_signal_pair[0]);
 	evutil_make_socket_closeonexec(base->sig.ev_signal_pair[1]);
 	base->sig.sh_old = NULL;
 	base->sig.sh_old_max = 0;
 	evutil_make_socket_nonblocking(base->sig.ev_signal_pair[0]);
 	evutil_make_socket_nonblocking(base->sig.ev_signal_pair[1]);
 	event_assign(&base->sig.ev_signal, base, base->sig.ev_signal_pair[1],
 		EV_READ | EV_PERSIST, evsig_cb, base);
 	base->sig.ev_signal.ev_flags |= EVLIST_INTERNAL;
 	event_priority_set(&base->sig.ev_signal, 0);
 	base->evsigsel = &evsigops;
 	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
 _evsig_set_handler(struct event_base *base,
     int evsignal, void (__cdecl *handler)(int))
 {
 #ifdef _EVENT_HAVE_SIGACTION
 	struct sigaction sa;
 #else
 	ev_sighandler_t sh;
 #endif
 	struct evsig_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 = mm_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),
 , (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] = mm_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 _EVENT_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");
 		mm_free(sig->sh_old[evsignal]);
 		sig->sh_old[evsignal] = NULL;
 		return (-1);
 	}
 #else
 	if ((sh = signal(evsignal, handler)) == SIG_ERR) {
 		event_warn("signal");
 		mm_free(sig->sh_old[evsignal]);
 		sig->sh_old[evsignal] = NULL;
 		return (-1);
 	}
 	*sig->sh_old[evsignal] = sh;
 #endif
 	return (0);
 }
 static int
 evsig_add(struct event_base *base, evutil_socket_t evsignal, short old, short events, void *p)
 {
 	struct evsig_info *sig = &base->sig;
 	(void)p;
 	EVUTIL_ASSERT(evsignal >= 0 && evsignal < NSIG);
 	/* catch signals if they happen quickly */
 	EVSIGBASE_LOCK();
 	if (evsig_base != base && evsig_base_n_signals_added) {
 		event_warnx("Added a signal to event base %p with signals "
 		    "already added to event_base %p.  Only one can have "
 		    "signals at a time with the %s backend.  The base with "
 		    "the most recently added signal or the most recent "
 		    "event_base_loop() call gets preference; do "
 		    "not rely on this behavior in future Libevent versions.",
 		    base, evsig_base, base->evsel->name);
 	}
 	evsig_base = base;
 	evsig_base_n_signals_added = ++sig->ev_n_signals_added;
 	evsig_base_fd = base->sig.ev_signal_pair[0];
 	EVSIGBASE_UNLOCK();
 	event_debug(("%s: %d: changing signal handler", __func__, (int)evsignal));
 	if (_evsig_set_handler(base, (int)evsignal, evsig_handler) == -1) {
 		goto err;
 	}
 	if (!sig->ev_signal_added) {
 		if (event_add(&sig->ev_signal, NULL))
 			goto err;
 		sig->ev_signal_added = 1;
 	}
 	return (0);
 err:
 	EVSIGBASE_LOCK();
 	--evsig_base_n_signals_added;
 	--sig->ev_n_signals_added;
 	EVSIGBASE_UNLOCK();
 	return (-1);
 }
 int
 _evsig_restore_handler(struct event_base *base, int evsignal)
 {
 	int ret = 0;
 	struct evsig_info *sig = &base->sig;
 #ifdef _EVENT_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 _EVENT_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
 	mm_free(sh);
 	return ret;
 }
 static int
 evsig_del(struct event_base *base, evutil_socket_t evsignal, short old, short events, void *p)
 {
 	EVUTIL_ASSERT(evsignal >= 0 && evsignal < NSIG);
 	event_debug(("%s: "EV_SOCK_FMT": restoring signal handler",
 		__func__, EV_SOCK_ARG(evsignal)));
 	EVSIGBASE_LOCK();
 	--evsig_base_n_signals_added;
 	--base->sig.ev_n_signals_added;
 	EVSIGBASE_UNLOCK();
 	return (_evsig_restore_handler(base, (int)evsignal));
 }
 static void __cdecl
 evsig_handler(int sig)
 {
 	int save_errno = errno;
 #ifdef WIN32
 	int socket_errno = EVUTIL_SOCKET_ERROR();
 #endif
 	ev_uint8_t msg;
 	if (evsig_base == NULL) {
 		event_warnx(
 			"%s: received signal %d, but have no base configured",
 			__func__, sig);
 		return;
 	}
 #ifndef _EVENT_HAVE_SIGACTION
 	signal(sig, evsig_handler);
 #endif
 	/* Wake up our notification mechanism */
 	msg = sig;
 	send(evsig_base_fd, (char*)&msg, 1, 0);
 	errno = save_errno;
 #ifdef WIN32
 	EVUTIL_SET_SOCKET_ERROR(socket_errno);
 #endif
 }
 void
 evsig_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;
 	}
 	/* debug event is created in evsig_init/event_assign even when
 	 * ev_signal_added == 0, so unassign is required */
 	event_debug_unassign(&base->sig.ev_signal);
 	for (i = 0; i < NSIG; ++i) {
 		if (i < base->sig.sh_old_max && base->sig.sh_old[i] != NULL)
 			_evsig_restore_handler(base, i);
 	}
 	EVSIGBASE_LOCK();
 	if (base == evsig_base) {
 		evsig_base = NULL;
 		evsig_base_n_signals_added = 0;
 		evsig_base_fd = -1;
 	}
 	EVSIGBASE_UNLOCK();
 	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) {
 		mm_free(base->sig.sh_old);
 		base->sig.sh_old = NULL;
 	}
 }
 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
 int
 evsig_global_setup_locks_(const int enable_locks)
 {
 	EVTHREAD_SETUP_GLOBAL_LOCK(evsig_base_lock, 0);
 	return 0;
 }
 #endif

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ipc/chromium/src/third_party/libevent/signal.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/signal.c