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
55 extern struct event_list signalqueue;
56
57 static sig_atomic_t evsigcaught[NSIG];
58 volatile sig_atomic_t evsignal_caught = 0;
59
60 static struct event ev_signal;
61 static int ev_signal_pair[2];
62 static int ev_signal_added;
63
64 static void evsignal_handler(int sig);
65
66 /* Callback for when the signal handler write a byte to our signaling socket */
67 static void
evsignal_cb(int fd,short what,void * arg)68 evsignal_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
89 void
evsignal_init(void)90 evsignal_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
110 int
evsignal_add(struct event * ev)111 evsignal_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
140 int
evsignal_del(struct event * ev)141 evsignal_del(struct event *ev)
142 {
143 int evsignal;
144
145 evsignal = EVENT_SIGNAL(ev);
146
147 return (sigaction(evsignal, (struct sigaction *)SIG_DFL, NULL));
148 }
149
150 static void
evsignal_handler(int sig)151 evsignal_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
163 void
evsignal_process(void)164 evsignal_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