2 * Copyright (c) 1998 Daniel M. Eischen <eischen@vigrid.com>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Daniel M. Eischen.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY DANIEL M. EISCHEN AND CONTRIBUTORS ``AS IS''
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 #include <pthread_np.h>
47 static int sigcounts[NSIG + 1];
48 static int sigfifo[NSIG + 1];
49 static int fifo_depth = 0;
50 static sigset_t suspender_mask;
51 static pthread_t suspender_tid;
55 sigsuspender (void *arg)
57 int save_count, status, i;
60 /* Run with all signals blocked. */
61 sigfillset (&run_mask);
62 sigprocmask (SIG_SETMASK, &run_mask, NULL);
64 /* Allow these signals to wake us up during a sigsuspend. */
65 sigfillset (&suspender_mask); /* Default action */
66 sigdelset (&suspender_mask, SIGINT); /* terminate */
67 sigdelset (&suspender_mask, SIGHUP); /* terminate */
68 sigdelset (&suspender_mask, SIGQUIT); /* create core image */
69 sigdelset (&suspender_mask, SIGURG); /* ignore */
70 sigdelset (&suspender_mask, SIGIO); /* ignore */
71 sigdelset (&suspender_mask, SIGUSR2); /* terminate */
73 while (sigcounts[SIGINT] == 0) {
74 save_count = sigcounts[SIGUSR2];
76 status = sigsuspend (&suspender_mask);
77 if ((status == 0) || (errno != EINTR)) {
78 fprintf (stderr, "Unable to suspend for signals, "
79 "errno %d, return value %d\n",
83 for (i = 0; i < fifo_depth; i++)
84 fprintf (stderr, "Sigsuspend woke up by signal %d\n",
95 sighandler (int signo)
97 sigset_t set, suspend_set;
100 if ((signo >= 0) && (signo <= NSIG))
104 * If we are running on behalf of the suspender thread,
105 * ensure that we have the correct mask set.
107 self = pthread_self ();
108 if (self == suspender_tid) {
109 sigfifo[fifo_depth] = signo;
112 " -> Suspender thread signal handler caught signal %d\n",
115 /* Get the current signal mask. */
116 sigprocmask (SIG_SETMASK, NULL, &set);
118 /* The handler should run with the current signal masked. */
119 suspend_set = suspender_mask;
120 sigaddset(&suspend_set, signo);
122 if (memcmp(&set, &suspend_set, sizeof(set)))
124 " >>> FAIL: sigsuspender signal handler running "
125 "with incorrect mask.\n");
129 " -> Main thread signal handler caught signal %d\n",
135 send_thread_signal (pthread_t tid, int signo)
137 if (pthread_kill (tid, signo) != 0) {
138 fprintf (stderr, "Unable to send thread signal, errno %d.\n",
146 send_process_signal (int signo)
148 if (kill (getpid (), signo) != 0) {
149 fprintf (stderr, "Unable to send process signal, errno %d.\n",
156 int main (int argc, char *argv[])
158 pthread_attr_t pattr;
160 struct sigaction act;
164 /* Initialize our signal counts. */
165 memset ((void *) sigcounts, 0, NSIG * sizeof (int));
167 /* Ignore signal SIGIO. */
168 sigemptyset (&act.sa_mask);
169 sigaddset (&act.sa_mask, SIGIO);
170 act.sa_handler = SIG_IGN;
172 sigaction (SIGIO, &act, NULL);
174 /* Install a signal handler for SIGURG. */
175 sigemptyset (&act.sa_mask);
176 sigaddset (&act.sa_mask, SIGURG);
177 act.sa_handler = sighandler;
178 act.sa_flags = SA_RESTART;
179 sigaction (SIGURG, &act, NULL);
181 /* Install a signal handler for SIGXCPU */
182 sigemptyset (&act.sa_mask);
183 sigaddset (&act.sa_mask, SIGXCPU);
184 sigaction (SIGXCPU, &act, NULL);
186 /* Get our current signal mask. */
187 sigprocmask (SIG_SETMASK, NULL, &oldset);
189 /* Mask out SIGUSR1 and SIGUSR2. */
191 sigaddset (&newset, SIGUSR1);
192 sigaddset (&newset, SIGUSR2);
193 sigprocmask (SIG_SETMASK, &newset, NULL);
195 /* Install a signal handler for SIGUSR1 */
196 sigemptyset (&act.sa_mask);
197 sigaddset (&act.sa_mask, SIGUSR1);
198 sigaction (SIGUSR1, &act, NULL);
200 /* Install a signal handler for SIGUSR2 */
201 sigemptyset (&act.sa_mask);
202 sigaddset (&act.sa_mask, SIGUSR2);
203 sigaction (SIGUSR2, &act, NULL);
206 * Initialize the thread attribute.
208 if ((pthread_attr_init (&pattr) != 0) ||
209 (pthread_attr_setdetachstate (&pattr,
210 PTHREAD_CREATE_JOINABLE) != 0)) {
211 fprintf (stderr, "Unable to initialize thread attributes.\n");
216 * Create the sigsuspender thread.
218 if (pthread_create (&suspender_tid, &pattr, sigsuspender, NULL) != 0) {
219 fprintf (stderr, "Unable to create thread, errno %d.\n", errno);
223 pthread_set_name_np (suspender_tid, "sigsuspender");
227 * Verify that an ignored signal doesn't cause a wakeup.
228 * We don't have a handler installed for SIGIO.
230 send_thread_signal (suspender_tid, SIGIO);
232 send_process_signal (SIGIO);
234 if (sigcounts[SIGIO] != 0)
235 fprintf (stderr, "FAIL: sigsuspend wakes up for ignored signal "
239 * Verify that a signal with a default action of ignore, for
240 * which we have a signal handler installed, will release a
243 send_thread_signal (suspender_tid, SIGURG);
245 send_process_signal (SIGURG);
247 if (sigcounts[SIGURG] != 2)
249 "FAIL: sigsuspend doesn't wake up for SIGURG.\n");
252 * Verify that a SIGUSR2 signal will release a sigsuspended
255 send_thread_signal (suspender_tid, SIGUSR2);
257 send_process_signal (SIGUSR2);
259 if (sigcounts[SIGUSR2] != 2)
261 "FAIL: sigsuspend doesn't wake up for SIGUSR2.\n");
264 * Verify that a signal, blocked in both the main and
265 * sigsuspender threads, does not cause the signal handler
268 send_thread_signal (suspender_tid, SIGUSR1);
270 send_process_signal (SIGUSR1);
272 if (sigcounts[SIGUSR1] != 0)
273 fprintf (stderr, "FAIL: signal hander called for SIGUSR1.\n");
276 * Verify that we can still kill the process for a signal
277 * not being waited on by sigwait.
279 send_process_signal (SIGPIPE);
280 fprintf (stderr, "FAIL: SIGPIPE did not terminate process.\n");
283 * Wait for the thread to finish.
285 pthread_join (suspender_tid, &exit_status);