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, SIGKILL); /* Cannot catch */
67 sigdelset (&suspender_mask, SIGSTOP); /* Cannot catch */
68 sigdelset (&suspender_mask, SIGINT); /* terminate */
69 sigdelset (&suspender_mask, SIGHUP); /* terminate */
70 sigdelset (&suspender_mask, SIGQUIT); /* create core image */
71 sigdelset (&suspender_mask, SIGURG); /* ignore */
72 sigdelset (&suspender_mask, SIGIO); /* ignore */
73 sigdelset (&suspender_mask, SIGUSR2); /* terminate */
75 while (sigcounts[SIGINT] == 0) {
76 save_count = sigcounts[SIGUSR2];
78 status = sigsuspend (&suspender_mask);
79 if ((status == 0) || (errno != EINTR)) {
80 fprintf (stderr, "Unable to suspend for signals, "
81 "errno %d, return value %d\n",
85 for (i = 0; i < fifo_depth; i++)
86 fprintf (stderr, "Sigsuspend woke up by signal %d\n",
97 sighandler (int signo)
99 sigset_t set, suspend_set;
102 if ((signo >= 0) && (signo <= NSIG))
106 * If we are running on behalf of the suspender thread,
107 * ensure that we have the correct mask set.
109 self = pthread_self ();
110 if (self == suspender_tid) {
111 sigfifo[fifo_depth] = signo;
114 " -> Suspender thread signal handler caught signal %d\n",
117 /* Get the current signal mask. */
118 sigprocmask (SIG_SETMASK, NULL, &set);
120 /* The handler should run with the current signal masked. */
121 suspend_set = suspender_mask;
122 sigaddset(&suspend_set, signo);
124 if (memcmp(&set, &suspend_set, sizeof(set)))
126 " >>> FAIL: sigsuspender signal handler running "
127 "with incorrect mask.\n");
131 " -> Main thread signal handler caught signal %d\n",
137 send_thread_signal (pthread_t tid, int signo)
139 if (pthread_kill (tid, signo) != 0) {
140 fprintf (stderr, "Unable to send thread signal, errno %d.\n",
148 send_process_signal (int signo)
150 if (kill (getpid (), signo) != 0) {
151 fprintf (stderr, "Unable to send process signal, errno %d.\n",
158 int main (int argc, char *argv[])
160 pthread_attr_t pattr;
162 struct sigaction act;
166 /* Initialize our signal counts. */
167 memset ((void *) sigcounts, 0, NSIG * sizeof (int));
169 /* Ignore signal SIGIO. */
170 sigemptyset (&act.sa_mask);
171 sigaddset (&act.sa_mask, SIGIO);
172 act.sa_handler = SIG_IGN;
174 sigaction (SIGIO, &act, NULL);
176 /* Install a signal handler for SIGURG. */
177 sigemptyset (&act.sa_mask);
178 sigaddset (&act.sa_mask, SIGURG);
179 act.sa_handler = sighandler;
180 act.sa_flags = SA_RESTART;
181 sigaction (SIGURG, &act, NULL);
183 /* Install a signal handler for SIGXCPU */
184 sigemptyset (&act.sa_mask);
185 sigaddset (&act.sa_mask, SIGXCPU);
186 sigaction (SIGXCPU, &act, NULL);
188 /* Get our current signal mask. */
189 sigprocmask (SIG_SETMASK, NULL, &oldset);
191 /* Mask out SIGUSR1 and SIGUSR2. */
193 sigaddset (&newset, SIGUSR1);
194 sigaddset (&newset, SIGUSR2);
195 sigprocmask (SIG_SETMASK, &newset, NULL);
197 /* Install a signal handler for SIGUSR1 */
198 sigemptyset (&act.sa_mask);
199 sigaddset (&act.sa_mask, SIGUSR1);
200 sigaction (SIGUSR1, &act, NULL);
202 /* Install a signal handler for SIGUSR2 */
203 sigemptyset (&act.sa_mask);
204 sigaddset (&act.sa_mask, SIGUSR2);
205 sigaction (SIGUSR2, &act, NULL);
208 * Initialize the thread attribute.
210 if ((pthread_attr_init (&pattr) != 0) ||
211 (pthread_attr_setdetachstate (&pattr,
212 PTHREAD_CREATE_JOINABLE) != 0)) {
213 fprintf (stderr, "Unable to initialize thread attributes.\n");
218 * Create the sigsuspender thread.
220 if (pthread_create (&suspender_tid, &pattr, sigsuspender, NULL) != 0) {
221 fprintf (stderr, "Unable to create thread, errno %d.\n", errno);
224 #if defined(_LIBC_R_)
225 pthread_set_name_np (suspender_tid, "sigsuspender");
229 * Verify that an ignored signal doesn't cause a wakeup.
230 * We don't have a handler installed for SIGIO.
232 send_thread_signal (suspender_tid, SIGIO);
234 send_process_signal (SIGIO);
236 if (sigcounts[SIGIO] != 0)
237 fprintf (stderr, "FAIL: sigsuspend wakes up for ignored signal "
241 * Verify that a signal with a default action of ignore, for
242 * which we have a signal handler installed, will release a
245 send_thread_signal (suspender_tid, SIGURG);
247 send_process_signal (SIGURG);
249 if (sigcounts[SIGURG] != 2)
251 "FAIL: sigsuspend doesn't wake up for SIGURG.\n");
254 * Verify that a SIGUSR2 signal will release a sigsuspended
257 send_thread_signal (suspender_tid, SIGUSR2);
259 send_process_signal (SIGUSR2);
261 if (sigcounts[SIGUSR2] != 2)
263 "FAIL: sigsuspend doesn't wake up for SIGUSR2.\n");
266 * Verify that a signal, blocked in both the main and
267 * sigsuspender threads, does not cause the signal handler
270 send_thread_signal (suspender_tid, SIGUSR1);
272 send_process_signal (SIGUSR1);
274 if (sigcounts[SIGUSR1] != 0)
275 fprintf (stderr, "FAIL: signal hander called for SIGUSR1.\n");
278 * Verify that we can still kill the process for a signal
279 * not being waited on by sigwait.
281 send_process_signal (SIGPIPE);
282 fprintf (stderr, "FAIL: SIGPIPE did not terminate process.\n");
285 * Wait for the thread to finish.
287 pthread_join (suspender_tid, &exit_status);