signal.c

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Author : Nick Mathewson
Date : 2012-02-29 15:07:33
Hash : 8ac3c4c2
Message : Have all visible internal function names end with an underscore. We haven't had a convention for naming internal functions in -internal.h versus naming visible functions in include/**.h. This patch changes every function declared in a -internal.h file to be named ending with an underscore. Static function names are unaffected, since there's no risk of calling them from outside Libevent. This is an automatic conversion. The script that produced was made by running the following script over the output of ctags --c-kinds=pf -o - *-internal.h | cut -f 1 | sort| uniq (GNU ctags was required.) ===== #!/usr/bin/perl -w -n use strict; BEGIN { print "#!/usr/bin/perl -w -i -p\n\n"; } chomp; my $ident = $_; next if ($ident =~ /_$/); next if ($ident =~ /^TAILQ/); my $better = "${ident}_"; print "s/(?<![A-Za-z0-9_])$ident(?![A-Za-z0-9_])/$better/g;\n"; === And then running the script below that it generated over all === the .c and .h files again #!/usr/bin/perl -w -i -p s/(?<![A-Za-z0-9_])bufferevent_async_can_connect(?![A-Za-z0-9_])/bufferevent_async_can_connect_/g; s/(?<![A-Za-z0-9_])bufferevent_async_connect(?![A-Za-z0-9_])/bufferevent_async_connect_/g; s/(?<![A-Za-z0-9_])bufferevent_async_new(?![A-Za-z0-9_])/bufferevent_async_new_/g; s/(?<![A-Za-z0-9_])bufferevent_async_set_connected(?![A-Za-z0-9_])/bufferevent_async_set_connected_/g; s/(?<![A-Za-z0-9_])bufferevent_decref(?![A-Za-z0-9_])/bufferevent_decref_/g; s/(?<![A-Za-z0-9_])bufferevent_disable_hard(?![A-Za-z0-9_])/bufferevent_disable_hard_/g; s/(?<![A-Za-z0-9_])bufferevent_enable_locking(?![A-Za-z0-9_])/bufferevent_enable_locking_/g; s/(?<![A-Za-z0-9_])bufferevent_incref(?![A-Za-z0-9_])/bufferevent_incref_/g; s/(?<![A-Za-z0-9_])bufferevent_init_common(?![A-Za-z0-9_])/bufferevent_init_common_/g; s/(?<![A-Za-z0-9_])bufferevent_remove_from_rate_limit_group_internal(?![A-Za-z0-9_])/bufferevent_remove_from_rate_limit_group_internal_/g; s/(?<![A-Za-z0-9_])bufferevent_suspend_read(?![A-Za-z0-9_])/bufferevent_suspend_read_/g; s/(?<![A-Za-z0-9_])bufferevent_suspend_write(?![A-Za-z0-9_])/bufferevent_suspend_write_/g; s/(?<![A-Za-z0-9_])bufferevent_unsuspend_read(?![A-Za-z0-9_])/bufferevent_unsuspend_read_/g; s/(?<![A-Za-z0-9_])bufferevent_unsuspend_write(?![A-Za-z0-9_])/bufferevent_unsuspend_write_/g; s/(?<![A-Za-z0-9_])evbuffer_commit_read(?![A-Za-z0-9_])/evbuffer_commit_read_/g; s/(?<![A-Za-z0-9_])evbuffer_commit_write(?![A-Za-z0-9_])/evbuffer_commit_write_/g; s/(?<![A-Za-z0-9_])evbuffer_invoke_callbacks(?![A-Za-z0-9_])/evbuffer_invoke_callbacks_/g; s/(?<![A-Za-z0-9_])evbuffer_launch_read(?![A-Za-z0-9_])/evbuffer_launch_read_/g; s/(?<![A-Za-z0-9_])evbuffer_launch_write(?![A-Za-z0-9_])/evbuffer_launch_write_/g; s/(?<![A-Za-z0-9_])evbuffer_overlapped_new(?![A-Za-z0-9_])/evbuffer_overlapped_new_/g; s/(?<![A-Za-z0-9_])evbuffer_set_parent(?![A-Za-z0-9_])/evbuffer_set_parent_/g; s/(?<![A-Za-z0-9_])event_active_nolock(?![A-Za-z0-9_])/event_active_nolock_/g; s/(?<![A-Za-z0-9_])event_base_add_virtual(?![A-Za-z0-9_])/event_base_add_virtual_/g; s/(?<![A-Za-z0-9_])event_base_assert_ok(?![A-Za-z0-9_])/event_base_assert_ok_/g; s/(?<![A-Za-z0-9_])event_base_del_virtual(?![A-Za-z0-9_])/event_base_del_virtual_/g; s/(?<![A-Za-z0-9_])event_base_get_deferred_cb_queue(?![A-Za-z0-9_])/event_base_get_deferred_cb_queue_/g; s/(?<![A-Za-z0-9_])event_base_get_iocp(?![A-Za-z0-9_])/event_base_get_iocp_/g; s/(?<![A-Za-z0-9_])event_base_start_iocp(?![A-Za-z0-9_])/event_base_start_iocp_/g; s/(?<![A-Za-z0-9_])event_base_stop_iocp(?![A-Za-z0-9_])/event_base_stop_iocp_/g; s/(?<![A-Za-z0-9_])event_changelist_add(?![A-Za-z0-9_])/event_changelist_add_/g; s/(?<![A-Za-z0-9_])event_changelist_del(?![A-Za-z0-9_])/event_changelist_del_/g; s/(?<![A-Za-z0-9_])event_changelist_freemem(?![A-Za-z0-9_])/event_changelist_freemem_/g; s/(?<![A-Za-z0-9_])event_changelist_init(?![A-Za-z0-9_])/event_changelist_init_/g; s/(?<![A-Za-z0-9_])event_changelist_remove_all(?![A-Za-z0-9_])/event_changelist_remove_all_/g; s/(?<![A-Za-z0-9_])event_deferred_cb_cancel(?![A-Za-z0-9_])/event_deferred_cb_cancel_/g; s/(?<![A-Za-z0-9_])event_deferred_cb_init(?![A-Za-z0-9_])/event_deferred_cb_init_/g; s/(?<![A-Za-z0-9_])event_deferred_cb_queue_init(?![A-Za-z0-9_])/event_deferred_cb_queue_init_/g; s/(?<![A-Za-z0-9_])event_deferred_cb_schedule(?![A-Za-z0-9_])/event_deferred_cb_schedule_/g; s/(?<![A-Za-z0-9_])event_get_win32_extension_fns(?![A-Za-z0-9_])/event_get_win32_extension_fns_/g; s/(?<![A-Za-z0-9_])event_iocp_activate_overlapped(?![A-Za-z0-9_])/event_iocp_activate_overlapped_/g; s/(?<![A-Za-z0-9_])event_iocp_port_associate(?![A-Za-z0-9_])/event_iocp_port_associate_/g; s/(?<![A-Za-z0-9_])event_iocp_port_launch(?![A-Za-z0-9_])/event_iocp_port_launch_/g; s/(?<![A-Za-z0-9_])event_iocp_shutdown(?![A-Za-z0-9_])/event_iocp_shutdown_/g; s/(?<![A-Za-z0-9_])event_overlapped_init(?![A-Za-z0-9_])/event_overlapped_init_/g; s/(?<![A-Za-z0-9_])evhttp_connection_connect(?![A-Za-z0-9_])/evhttp_connection_connect_/g; s/(?<![A-Za-z0-9_])evhttp_connection_fail(?![A-Za-z0-9_])/evhttp_connection_fail_/g; s/(?<![A-Za-z0-9_])evhttp_connection_reset(?![A-Za-z0-9_])/evhttp_connection_reset_/g; s/(?<![A-Za-z0-9_])evhttp_parse_firstline(?![A-Za-z0-9_])/evhttp_parse_firstline_/g; s/(?<![A-Za-z0-9_])evhttp_parse_headers(?![A-Za-z0-9_])/evhttp_parse_headers_/g; s/(?<![A-Za-z0-9_])evhttp_response_code(?![A-Za-z0-9_])/evhttp_response_code_/g; s/(?<![A-Za-z0-9_])evhttp_send_page(?![A-Za-z0-9_])/evhttp_send_page_/g; s/(?<![A-Za-z0-9_])evhttp_start_read(?![A-Za-z0-9_])/evhttp_start_read_/g; s/(?<![A-Za-z0-9_])EVLOCK_TRY_LOCK(?![A-Za-z0-9_])/EVLOCK_TRY_LOCK_/g; s/(?<![A-Za-z0-9_])evmap_check_integrity(?![A-Za-z0-9_])/evmap_check_integrity_/g; s/(?<![A-Za-z0-9_])evmap_delete_all(?![A-Za-z0-9_])/evmap_delete_all_/g; s/(?<![A-Za-z0-9_])evmap_foreach_event(?![A-Za-z0-9_])/evmap_foreach_event_/g; s/(?<![A-Za-z0-9_])evmap_io_active(?![A-Za-z0-9_])/evmap_io_active_/g; s/(?<![A-Za-z0-9_])evmap_io_add(?![A-Za-z0-9_])/evmap_io_add_/g; s/(?<![A-Za-z0-9_])evmap_io_clear(?![A-Za-z0-9_])/evmap_io_clear_/g; s/(?<![A-Za-z0-9_])evmap_io_del(?![A-Za-z0-9_])/evmap_io_del_/g; s/(?<![A-Za-z0-9_])evmap_io_get_fdinfo(?![A-Za-z0-9_])/evmap_io_get_fdinfo_/g; s/(?<![A-Za-z0-9_])evmap_io_initmap(?![A-Za-z0-9_])/evmap_io_initmap_/g; s/(?<![A-Za-z0-9_])evmap_reinit(?![A-Za-z0-9_])/evmap_reinit_/g; s/(?<![A-Za-z0-9_])evmap_signal_active(?![A-Za-z0-9_])/evmap_signal_active_/g; s/(?<![A-Za-z0-9_])evmap_signal_add(?![A-Za-z0-9_])/evmap_signal_add_/g; s/(?<![A-Za-z0-9_])evmap_signal_clear(?![A-Za-z0-9_])/evmap_signal_clear_/g; s/(?<![A-Za-z0-9_])evmap_signal_del(?![A-Za-z0-9_])/evmap_signal_del_/g; s/(?<![A-Za-z0-9_])evmap_signal_initmap(?![A-Za-z0-9_])/evmap_signal_initmap_/g; s/(?<![A-Za-z0-9_])evrpc_hook_associate_meta(?![A-Za-z0-9_])/evrpc_hook_associate_meta_/g; s/(?<![A-Za-z0-9_])evrpc_hook_context_free(?![A-Za-z0-9_])/evrpc_hook_context_free_/g; s/(?<![A-Za-z0-9_])evrpc_hook_meta_new(?![A-Za-z0-9_])/evrpc_hook_meta_new_/g; s/(?<![A-Za-z0-9_])evrpc_reqstate_free(?![A-Za-z0-9_])/evrpc_reqstate_free_/g; s/(?<![A-Za-z0-9_])evsig_dealloc(?![A-Za-z0-9_])/evsig_dealloc_/g; s/(?<![A-Za-z0-9_])evsig_init(?![A-Za-z0-9_])/evsig_init_/g; s/(?<![A-Za-z0-9_])evsig_set_base(?![A-Za-z0-9_])/evsig_set_base_/g; s/(?<![A-Za-z0-9_])ev_token_bucket_get_tick(?![A-Za-z0-9_])/ev_token_bucket_get_tick_/g; s/(?<![A-Za-z0-9_])ev_token_bucket_init(?![A-Za-z0-9_])/ev_token_bucket_init_/g; s/(?<![A-Za-z0-9_])ev_token_bucket_update(?![A-Za-z0-9_])/ev_token_bucket_update_/g; s/(?<![A-Za-z0-9_])evutil_accept4(?![A-Za-z0-9_])/evutil_accept4_/g; s/(?<![A-Za-z0-9_])evutil_addrinfo_append(?![A-Za-z0-9_])/evutil_addrinfo_append_/g; s/(?<![A-Za-z0-9_])evutil_adjust_hints_for_addrconfig(?![A-Za-z0-9_])/evutil_adjust_hints_for_addrconfig_/g; s/(?<![A-Za-z0-9_])evutil_ersatz_socketpair(?![A-Za-z0-9_])/evutil_ersatz_socketpair_/g; s/(?<![A-Za-z0-9_])evutil_eventfd(?![A-Za-z0-9_])/evutil_eventfd_/g; s/(?<![A-Za-z0-9_])evutil_format_sockaddr_port(?![A-Za-z0-9_])/evutil_format_sockaddr_port_/g; s/(?<![A-Za-z0-9_])evutil_getaddrinfo_async(?![A-Za-z0-9_])/evutil_getaddrinfo_async_/g; s/(?<![A-Za-z0-9_])evutil_getaddrinfo_common(?![A-Za-z0-9_])/evutil_getaddrinfo_common_/g; s/(?<![A-Za-z0-9_])evutil_getenv(?![A-Za-z0-9_])/evutil_getenv_/g; s/(?<![A-Za-z0-9_])evutil_hex_char_to_int(?![A-Za-z0-9_])/evutil_hex_char_to_int_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISALNUM(?![A-Za-z0-9_])/EVUTIL_ISALNUM_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISALPHA(?![A-Za-z0-9_])/EVUTIL_ISALPHA_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISDIGIT(?![A-Za-z0-9_])/EVUTIL_ISDIGIT_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISLOWER(?![A-Za-z0-9_])/EVUTIL_ISLOWER_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISPRINT(?![A-Za-z0-9_])/EVUTIL_ISPRINT_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISSPACE(?![A-Za-z0-9_])/EVUTIL_ISSPACE_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISUPPER(?![A-Za-z0-9_])/EVUTIL_ISUPPER_/g; s/(?<![A-Za-z0-9_])EVUTIL_ISXDIGIT(?![A-Za-z0-9_])/EVUTIL_ISXDIGIT_/g; s/(?<![A-Za-z0-9_])evutil_load_windows_system_library(?![A-Za-z0-9_])/evutil_load_windows_system_library_/g; s/(?<![A-Za-z0-9_])evutil_make_internal_pipe(?![A-Za-z0-9_])/evutil_make_internal_pipe_/g; s/(?<![A-Za-z0-9_])evutil_new_addrinfo(?![A-Za-z0-9_])/evutil_new_addrinfo_/g; s/(?<![A-Za-z0-9_])evutil_open_closeonexec(?![A-Za-z0-9_])/evutil_open_closeonexec_/g; s/(?<![A-Za-z0-9_])evutil_read_file(?![A-Za-z0-9_])/evutil_read_file_/g; s/(?<![A-Za-z0-9_])evutil_resolve(?![A-Za-z0-9_])/evutil_resolve_/g; s/(?<![A-Za-z0-9_])evutil_set_evdns_getaddrinfo_fn(?![A-Za-z0-9_])/evutil_set_evdns_getaddrinfo_fn_/g; s/(?<![A-Za-z0-9_])evutil_sockaddr_is_loopback(?![A-Za-z0-9_])/evutil_sockaddr_is_loopback_/g; s/(?<![A-Za-z0-9_])evutil_socket(?![A-Za-z0-9_])/evutil_socket_/g; s/(?<![A-Za-z0-9_])evutil_socket_connect(?![A-Za-z0-9_])/evutil_socket_connect_/g; 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signal.c

/*	$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"
#include "evconfig-private.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, 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[1];
	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) {
#ifdef _WIN32
		n = recv(fd, signals, sizeof(signals), 0);
#else
		n = read(fd, signals, sizeof(signals));
#endif
		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_make_internal_pipe_(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;
	}

	if (base->sig.sh_old) {
		mm_free(base->sig.sh_old);
	}
	base->sig.sh_old = NULL;
	base->sig.sh_old_max = 0;

	event_assign(&base->sig.ev_signal, base, base->sig.ev_signal_pair[0],
		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),
		    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] = 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[1];
	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

	if (evsignal >= sig->sh_old_max) {
		/* Can't actually restore. */
		/* XXXX.*/
		return 0;
	}

	/* 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: %d: restoring signal handler", __func__, 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;
#ifdef _WIN32
	send(evsig_base_fd, (char*)&msg, 1, 0);
#else
	{
		int r = write(evsig_base_fd, (char*)&msg, 1);
		(void)r; /* Suppress 'unused return value' and 'unused var' */
	}
#endif
	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

kc3-lang/libevent/signal.c

Commit

kc3-lang/libevent /signal.c