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-rw-r--r--libevent/signal.c357
1 files changed, 357 insertions, 0 deletions
diff --git a/libevent/signal.c b/libevent/signal.c
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index 00000000000..74fa23f688a
--- /dev/null
+++ b/libevent/signal.c
@@ -0,0 +1,357 @@
+/* $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.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#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);
+
+/* 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)
+ 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]);
+
+ 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]);
+ return (-1);
+ }
+#else
+ if ((sh = signal(evsignal, handler)) == SIG_ERR) {
+ event_warn("signal");
+ free(sig->sh_old[evsignal]);
+ 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);
+ }
+
+ EVUTIL_CLOSESOCKET(base->sig.ev_signal_pair[0]);
+ base->sig.ev_signal_pair[0] = -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 evsignal_del() */
+ free(base->sig.sh_old);
+}
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