1/*	$OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey 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#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <sys/types.h>
34#ifdef HAVE_SYS_TIME_H
35#include <sys/time.h>
36#else
37#include <sys/_time.h>
38#endif
39#include <sys/queue.h>
40#include <sys/socket.h>
41#include <signal.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <unistd.h>
46#include <errno.h>
47#ifdef HAVE_FCNTL_H
48#include <fcntl.h>
49#endif
50
51#include "event.h"
52#include "evsignal.h"
53#include "log.h"
54
55extern struct event_list signalqueue;
56
57static sig_atomic_t evsigcaught[NSIG];
58volatile sig_atomic_t evsignal_caught = 0;
59
60static struct event ev_signal;
61static int ev_signal_pair[2];
62static int ev_signal_added;
63
64static void evsignal_handler(int sig);
65
66/* Callback for when the signal handler write a byte to our signaling socket */
67static void
68evsignal_cb(int fd, short what, void *arg)
69{
70	static char signals[100];
71	struct event *ev = arg;
72	ssize_t n;
73
74	n = read(fd, signals, sizeof(signals));
75	if (n == -1)
76		event_err(1, "%s: read", __func__);
77	event_add(ev, NULL);
78}
79
80#ifdef HAVE_SETFD
81#define FD_CLOSEONEXEC(x) do { \
82        if (fcntl(x, F_SETFD, 1) == -1) \
83                event_warn("fcntl(%d, F_SETFD)", x); \
84} while (0)
85#else
86#define FD_CLOSEONEXEC(x)
87#endif
88
89void
90evsignal_init(void)
91{
92	/*
93	 * Our signal handler is going to write to one end of the socket
94	 * pair to wake up our event loop.  The event loop then scans for
95	 * signals that got delivered.
96	 */
97	if (socketpair(AF_UNIX, SOCK_STREAM, 0, ev_signal_pair) == -1)
98		event_err(1, "%s: socketpair", __func__);
99
100	FD_CLOSEONEXEC(ev_signal_pair[0]);
101	FD_CLOSEONEXEC(ev_signal_pair[1]);
102
103	fcntl(ev_signal_pair[0], F_SETFL, O_NONBLOCK);
104
105	event_set(&ev_signal, ev_signal_pair[1], EV_READ,
106	    evsignal_cb, &ev_signal);
107	ev_signal.ev_flags |= EVLIST_INTERNAL;
108}
109
110int
111evsignal_add(struct event *ev)
112{
113	int evsignal;
114	struct sigaction sa;
115
116	if (ev->ev_events & (EV_READ|EV_WRITE))
117		event_errx(1, "%s: EV_SIGNAL incompatible use", __func__);
118	evsignal = EVENT_SIGNAL(ev);
119
120	memset(&sa, 0, sizeof(sa));
121	sa.sa_handler = evsignal_handler;
122	sigfillset(&sa.sa_mask);
123	sa.sa_flags |= SA_RESTART;
124
125	if (sigaction(evsignal, &sa, NULL) == -1)
126		return (-1);
127
128	if (!ev_signal_added) {
129		ev_signal_added = 1;
130		event_add(&ev_signal, NULL);
131	}
132
133	return (0);
134}
135
136/*
137 * Nothing to be done here.
138 */
139
140int
141evsignal_del(struct event *ev)
142{
143	int evsignal;
144
145	evsignal = EVENT_SIGNAL(ev);
146
147	return (sigaction(EVENT_SIGNAL(ev),(struct sigaction *)SIG_DFL, NULL));
148}
149
150static void
151evsignal_handler(int sig)
152{
153	int save_errno = errno;
154
155	evsigcaught[sig]++;
156	evsignal_caught = 1;
157
158	/* Wake up our notification mechanism */
159	write(ev_signal_pair[0], "a", 1);
160	errno = save_errno;
161}
162
163void
164evsignal_process(void)
165{
166	struct event *ev;
167	sig_atomic_t ncalls;
168
169	evsignal_caught = 0;
170	TAILQ_FOREACH(ev, &signalqueue, ev_signal_next) {
171		ncalls = evsigcaught[EVENT_SIGNAL(ev)];
172		if (ncalls) {
173			if (!(ev->ev_events & EV_PERSIST))
174				event_del(ev);
175			event_active(ev, EV_SIGNAL, ncalls);
176			evsigcaught[EVENT_SIGNAL(ev)] = 0;
177		}
178	}
179}
180
181