Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libevent/signal.c	Lines:	106	125	84.8 %
Date:	2017-11-13	Branches:	44	58	75.9 %


/*	$OpenBSD: signal.c,v 1.25 2015/01/06 11:42:37 bluhm 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 <sys/types.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <sys/socket.h>

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <assert.h>

#include "event.h"
#include "event-internal.h"
#include "evsignal.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];
	ssize_t n;

	n = recv(fd, signals, sizeof(signals), 0);
	if (n == -1) {
		if (errno != EAGAIN)
			event_err(1, "%s: read", __func__);
	}
}

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 (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
	    0, base->sig.ev_signal_pair) == -1) {
		event_err(1, "%s: socketpair", __func__);
		return -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]);

	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))
{
	struct sigaction sa;
	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 = reallocarray(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 */
	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);
	}

	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;
	struct sigaction *sh;

	/* restore previous handler */
	sh = sig->sh_old[evsignal];
	sig->sh_old[evsignal] = NULL;
	if (sigaction(evsignal, sh, NULL) == -1) {
		event_warn("sigaction");
		ret = -1;
	}
	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;

	/* 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) {
		close(base->sig.ev_signal_pair[0]);
		base->sig.ev_signal_pair[0] = -1;
	}
	if (base->sig.ev_signal_pair[1] != -1) {
		close(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() */
	if (base->sig.sh_old) {
		free(base->sig.sh_old);
		base->sig.sh_old = NULL;
	}
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: signal.c,v 1.25 2015/01/06 11:42:37 bluhm Exp $ */
2
3			/*
4			* Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
5			* All rights reserved.
6			*
7			* Redistribution and use in source and binary forms, with or without
8			* modification, are permitted provided that the following conditions
9			* are met:
10			* 1. Redistributions of source code must retain the above copyright
11			* notice, this list of conditions and the following disclaimer.
12			* 2. Redistributions in binary form must reproduce the above copyright
13			* notice, this list of conditions and the following disclaimer in the
14			* documentation and/or other materials provided with the distribution.
15			* 3. The name of the author may not be used to endorse or promote products
16			* derived from this software without specific prior written permission.
17			*
18			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19			* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20			* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21			* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22			* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23			* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28			*/
29
30			#include <sys/types.h>
31			#include <sys/time.h>
32			#include <sys/queue.h>
33			#include <sys/socket.h>
34
35			#include <signal.h>
36			#include <stdio.h>
37			#include <stdlib.h>
38			#include <string.h>
39			#include <unistd.h>
40			#include <errno.h>
41			#include <fcntl.h>
42			#include <assert.h>
43
44			#include "event.h"
45			#include "event-internal.h"
46			#include "evsignal.h"
47			#include "log.h"
48
49			struct event_base *evsignal_base = NULL;
50
51			static void evsignal_handler(int sig);
52
53			/* Callback for when the signal handler write a byte to our signaling socket */
54			static void
55			evsignal_cb(int fd, short what, void *arg)
56			{
57			static char signals[1];
58			ssize_t n;
59
60		132	n = recv(fd, signals, sizeof(signals), 0);
61	✗✓	66	if (n == -1) {
62			if (errno != EAGAIN)
63			event_err(1, "%s: read", __func__);
64			}
65		66	}
66
67			int
68			evsignal_init(struct event_base *base)
69			{
70			int i;
71
72			/*
73			* Our signal handler is going to write to one end of the socket
74			* pair to wake up our event loop. The event loop then scans for
75			* signals that got delivered.
76			*/
77	✗✓	288	if (socketpair(AF_UNIX, SOCK_STREAM \| SOCK_CLOEXEC \| SOCK_NONBLOCK,
78		432	0, base->sig.ev_signal_pair) == -1) {
79			event_err(1, "%s: socketpair", __func__);
80			return -1;
81			}
82
83		144	base->sig.sh_old = NULL;
84		144	base->sig.sh_old_max = 0;
85		144	base->sig.evsignal_caught = 0;
86		144	memset(&base->sig.evsigcaught, 0, sizeof(sig_atomic_t)*NSIG);
87			/* initialize the queues for all events */
88	✓✓	9792	for (i = 0; i < NSIG; ++i)
89		4752	TAILQ_INIT(&base->sig.evsigevents[i]);
90
91		288	event_set(&base->sig.ev_signal, base->sig.ev_signal_pair[1],
92		144	EV_READ \| EV_PERSIST, evsignal_cb, &base->sig.ev_signal);
93		144	base->sig.ev_signal.ev_base = base;
94		144	base->sig.ev_signal.ev_flags \|= EVLIST_INTERNAL;
95
96		144	return 0;
97		144	}
98
99			/* Helper: set the signal handler for evsignal to handler in base, so that
100			* we can restore the original handler when we clear the current one. */
101			int
102			_evsignal_set_handler(struct event_base *base,
103			int evsignal, void (*handler)(int))
104			{
105		234	struct sigaction sa;
106		117	struct evsignal_info *sig = &base->sig;
107			void *p;
108
109			/*
110			* resize saved signal handler array up to the highest signal number.
111			* a dynamic array is used to keep footprint on the low side.
112			*/
113	✓✓	117	if (evsignal >= sig->sh_old_max) {
114		90	int new_max = evsignal + 1;
115			event_debug(("%s: evsignal (%d) >= sh_old_max (%d), resizing",
116			__func__, evsignal, sig->sh_old_max));
117		90	p = reallocarray(sig->sh_old, new_max, sizeof(*sig->sh_old));
118	✗✓	90	if (p == NULL) {
119			event_warn("realloc");
120			return (-1);
121			}
122
123		180	memset((char )p + sig->sh_old_max sizeof(*sig->sh_old),
124		90	0, (new_max - sig->sh_old_max) * sizeof(*sig->sh_old));
125
126		90	sig->sh_old_max = new_max;
127		90	sig->sh_old = p;
128	✓✗	90	}
129
130			/* allocate space for previous handler out of dynamic array */
131		117	sig->sh_old[evsignal] = malloc(sizeof *sig->sh_old[evsignal]);
132	✗✓	117	if (sig->sh_old[evsignal] == NULL) {
133			event_warn("malloc");
134			return (-1);
135			}
136
137			/* save previous handler and setup new handler */
138		117	memset(&sa, 0, sizeof(sa));
139		117	sa.sa_handler = handler;
140		117	sa.sa_flags \|= SA_RESTART;
141		117	sigfillset(&sa.sa_mask);
142
143	✗✓	117	if (sigaction(evsignal, &sa, sig->sh_old[evsignal]) == -1) {
144			event_warn("sigaction");
145			free(sig->sh_old[evsignal]);
146			sig->sh_old[evsignal] = NULL;
147			return (-1);
148			}
149
150		117	return (0);
151		117	}
152
153			int
154			evsignal_add(struct event *ev)
155			{
156			int evsignal;
157		168	struct event_base *base = ev->ev_base;
158		84	struct evsignal_info *sig = &ev->ev_base->sig;
159
160	✗✓	84	if (ev->ev_events & (EV_READ\|EV_WRITE))
161			event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
162		84	evsignal = EVENT_SIGNAL(ev);
163			assert(evsignal >= 0 && evsignal < NSIG);
164	✓✓	84	if (TAILQ_EMPTY(&sig->evsigevents[evsignal])) {
165			event_debug(("%s: %p: changing signal handler", __func__, ev));
166	✗✓	156	if (_evsignal_set_handler(
167		78	base, evsignal, evsignal_handler) == -1)
168			return (-1);
169
170			/* catch signals if they happen quickly */
171		78	evsignal_base = base;
172
173	✓✓	78	if (!sig->ev_signal_added) {
174	✗✓	54	if (event_add(&sig->ev_signal, NULL))
175			return (-1);
176		54	sig->ev_signal_added = 1;
177		54	}
178			}
179
180			/* multiple events may listen to the same signal */
181		84	TAILQ_INSERT_TAIL(&sig->evsigevents[evsignal], ev, ev_signal_next);
182
183		84	return (0);
184		84	}
185
186			int
187			_evsignal_restore_handler(struct event_base *base, int evsignal)
188			{
189			int ret = 0;
190		234	struct evsignal_info *sig = &base->sig;
191			struct sigaction *sh;
192
193			/* restore previous handler */
194		117	sh = sig->sh_old[evsignal];
195		117	sig->sh_old[evsignal] = NULL;
196	✗✓	117	if (sigaction(evsignal, sh, NULL) == -1) {
197			event_warn("sigaction");
198			ret = -1;
199			}
200		117	free(sh);
201
202		117	return ret;
203			}
204
205			int
206			evsignal_del(struct event *ev)
207			{
208		156	struct event_base *base = ev->ev_base;
209		78	struct evsignal_info *sig = &base->sig;
210		78	int evsignal = EVENT_SIGNAL(ev);
211
212			assert(evsignal >= 0 && evsignal < NSIG);
213
214			/* multiple events may listen to the same signal */
215	✓✓	234	TAILQ_REMOVE(&sig->evsigevents[evsignal], ev, ev_signal_next);
216
217	✓✓	78	if (!TAILQ_EMPTY(&sig->evsigevents[evsignal]))
218		6	return (0);
219
220			event_debug(("%s: %p: restoring signal handler", __func__, ev));
221
222		72	return (_evsignal_restore_handler(ev->ev_base, EVENT_SIGNAL(ev)));
223		78	}
224
225			static void
226			evsignal_handler(int sig)
227			{
228		132	int save_errno = errno;
229
230	✗✓	66	if (evsignal_base == NULL) {
231			event_warn(
232			"%s: received signal %d, but have no base configured",
233			__func__, sig);
234			return;
235			}
236
237		66	evsignal_base->sig.evsigcaught[sig]++;
238		66	evsignal_base->sig.evsignal_caught = 1;
239
240			/* Wake up our notification mechanism */
241		66	send(evsignal_base->sig.ev_signal_pair[0], "a", 1, 0);
242		66	errno = save_errno;
243		132	}
244
245			void
246			evsignal_process(struct event_base *base)
247			{
248		132	struct evsignal_info *sig = &base->sig;
249			struct event ev, next_ev;
250			sig_atomic_t ncalls;
251			int i;
252
253		66	base->sig.evsignal_caught = 0;
254	✓✓	4356	for (i = 1; i < NSIG; ++i) {
255		2112	ncalls = sig->evsigcaught[i];
256	✓✓	2112	if (ncalls == 0)
257			continue;
258		66	sig->evsigcaught[i] -= ncalls;
259
260	✓✓	276	for (ev = TAILQ_FIRST(&sig->evsigevents[i]);
261		138	ev != NULL; ev = next_ev) {
262		72	next_ev = TAILQ_NEXT(ev, ev_signal_next);
263	✗✓	72	if (!(ev->ev_events & EV_PERSIST))
264			event_del(ev);
265		72	event_active(ev, EV_SIGNAL, ncalls);
266			}
267
268			}
269		66	}
270
271			void
272			evsignal_dealloc(struct event_base *base)
273			{
274			int i = 0;
275	✓✓	288	if (base->sig.ev_signal_added) {
276		36	event_del(&base->sig.ev_signal);
277		36	base->sig.ev_signal_added = 0;
278		36	}
279	✓✓	9792	for (i = 0; i < NSIG; ++i) {
280	✓✓✓✓	6516	if (i < base->sig.sh_old_max && base->sig.sh_old[i] != NULL)
281		9	_evsignal_restore_handler(base, i);
282			}
283
284	✓✓	144	if (base->sig.ev_signal_pair[0] != -1) {
285		96	close(base->sig.ev_signal_pair[0]);
286		96	base->sig.ev_signal_pair[0] = -1;
287		96	}
288	✓✓	144	if (base->sig.ev_signal_pair[1] != -1) {
289		96	close(base->sig.ev_signal_pair[1]);
290		96	base->sig.ev_signal_pair[1] = -1;
291		96	}
292		144	base->sig.sh_old_max = 0;
293
294			/* per index frees are handled in evsignal_del() */
295	✓✓	144	if (base->sig.sh_old) {
296		63	free(base->sig.sh_old);
297		63	base->sig.sh_old = NULL;
298		63	}
299		144	}