1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
|
/* $OpenBSD: sigwait.c,v 1.1 2001/08/15 14:37:16 fgsch Exp $ */
/*
* Copyright (c) 1998 Daniel M. Eischen <eischen@vigrid.com>
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Daniel M. Eischen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY DANIEL M. EISCHEN AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <pthread_np.h>
#include "test.h"
static int sigcounts[NSIG + 1];
static sigset_t wait_mask;
static pthread_mutex_t waiter_mutex;
static void *
sigwaiter (void *arg)
{
int signo;
sigset_t mask;
SET_NAME("sigwaiter");
/* Block SIGHUP */
sigemptyset (&mask);
sigaddset (&mask, SIGHUP);
CHECKe(sigprocmask (SIG_BLOCK, &mask, NULL));
while (sigcounts[SIGINT] == 0) {
printf("Sigwait waiting (thread %p)\n", pthread_self());
CHECKe(sigwait (&wait_mask, &signo));
sigcounts[signo]++;
printf ("Sigwait caught signal %d (%s)\n", signo,
strsignal(signo));
/* Allow the main thread to prevent the sigwait. */
CHECKr(pthread_mutex_lock (&waiter_mutex));
CHECKr(pthread_mutex_unlock (&waiter_mutex));
}
return (arg);
}
static void
sighandler (int signo)
{
printf (" -> Signal handler caught signal %d (%s) in thread %p\n",
signo, strsignal(signo), pthread_self());
if ((signo >= 0) && (signo <= NSIG))
sigcounts[signo]++;
}
int main (int argc, char *argv[])
{
pthread_mutexattr_t mattr;
pthread_attr_t pattr;
pthread_t tid;
struct sigaction act;
/* Initialize our signal counts. */
memset ((void *) sigcounts, 0, NSIG * sizeof (int));
/* Setupt our wait mask. */
sigemptyset (&wait_mask); /* Default action */
sigaddset (&wait_mask, SIGHUP); /* terminate */
sigaddset (&wait_mask, SIGINT); /* terminate */
sigaddset (&wait_mask, SIGQUIT); /* create core image */
sigaddset (&wait_mask, SIGURG); /* ignore */
sigaddset (&wait_mask, SIGIO); /* ignore */
sigaddset (&wait_mask, SIGUSR1); /* terminate */
/* Ignore signals SIGHUP and SIGIO. */
sigemptyset (&act.sa_mask);
sigaddset (&act.sa_mask, SIGHUP);
sigaddset (&act.sa_mask, SIGIO);
act.sa_handler = SIG_IGN;
act.sa_flags = 0;
CHECKe(sigaction (SIGHUP, &act, NULL));
CHECKe(sigaction (SIGIO, &act, NULL));
/* Install a signal handler for SIGURG */
sigemptyset (&act.sa_mask);
sigaddset (&act.sa_mask, SIGURG);
act.sa_handler = sighandler;
act.sa_flags = SA_RESTART;
CHECKe(sigaction (SIGURG, &act, NULL));
/* Install a signal handler for SIGXCPU */
sigemptyset (&act.sa_mask);
sigaddset (&act.sa_mask, SIGXCPU);
CHECKe(sigaction (SIGXCPU, &act, NULL));
/*
* Initialize the thread attribute.
*/
CHECKr(pthread_attr_init (&pattr));
CHECKr(pthread_attr_setdetachstate (&pattr, PTHREAD_CREATE_JOINABLE));
/*
* Initialize and create a mutex.
*/
CHECKr(pthread_mutexattr_init (&mattr));
CHECKr(pthread_mutex_init (&waiter_mutex, &mattr));
/*
* Create the sigwaiter thread.
*/
CHECKr(pthread_create (&tid, &pattr, sigwaiter, NULL));
/*
* Verify that an ignored signal doesn't cause a wakeup.
* We don't have a handler installed for SIGIO.
*/
CHECKr(pthread_kill (tid, SIGIO));
sleep (1);
CHECKe(kill(getpid(), SIGIO));
sleep (1);
/* sigwait should not wake up for ignored signal SIGIO */
ASSERT(sigcounts[SIGIO] == 0);
/*
* Verify that a signal with a default action of ignore, for
* which we have a signal handler installed, will release a sigwait.
*/
CHECKr(pthread_kill (tid, SIGURG));
sleep (1);
CHECKe(kill(getpid(), SIGURG));
sleep (1);
/* sigwait should wake up for SIGURG */
ASSERT(sigcounts[SIGURG] == 2);
/*
* Verify that a signal with a default action that terminates
* the process will release a sigwait.
*/
CHECKr(pthread_kill (tid, SIGUSR1));
sleep (1);
CHECKe(kill(getpid(), SIGUSR1));
sleep (1);
if (sigcounts[SIGUSR1] != 2)
printf ("FAIL: sigwait doesn't wake up for SIGUSR1.\n");
/*
* Verify that if we install a signal handler for a previously
* ignored signal, an occurrence of this signal will release
* the (already waiting) sigwait.
*/
/* Install a signal handler for SIGHUP. */
sigemptyset (&act.sa_mask);
sigaddset (&act.sa_mask, SIGHUP);
act.sa_handler = sighandler;
act.sa_flags = SA_RESTART;
CHECKe(sigaction (SIGHUP, &act, NULL));
/* Sending SIGHUP should release the sigwait. */
CHECKe(kill(getpid(), SIGHUP));
sleep (1);
CHECKr(pthread_kill (tid, SIGHUP));
sleep (1);
/* sigwait should wake up for SIGHUP */
ASSERT(sigcounts[SIGHUP] == 2);
/*
* Verify that a pending signal in the waiters mask will
* cause sigwait to return the pending signal. We do this
* by taking the waiters mutex and signaling the waiter to
* release him from the sigwait. The waiter will block
* on taking the mutex, and we can then send the waiter a
* signal which should be added to his pending signals.
* The next time the waiter does a sigwait, he should
* return with the pending signal.
*/
sigcounts[SIGHUP] = 0;
CHECKr(pthread_mutex_lock (&waiter_mutex));
/* Release the waiter from sigwait. */
CHECKe(kill(getpid(), SIGHUP));
sleep (1);
/* sigwait should wake up for SIGHUP */
ASSERT(sigcounts[SIGHUP] == 1);
/*
* Add SIGHUP to all threads pending signals. Since there is
* a signal handler installed for SIGHUP and this signal is
* blocked from the waiter thread and unblocked in the main
* thread, the signal handler should be called once for SIGHUP.
*/
CHECKe(kill(getpid(), SIGHUP));
/* Release the waiter thread and allow him to run. */
CHECKr(pthread_mutex_unlock (&waiter_mutex));
sleep (1);
/* sigwait should return for pending SIGHUP */
ASSERT(sigcounts[SIGHUP] == 3);
/*
* Repeat the above test using pthread_kill and SIGUSR1
*/
sigcounts[SIGUSR1] = 0;
CHECKr(pthread_mutex_lock (&waiter_mutex));
/* Release the waiter from sigwait. */
CHECKr(pthread_kill (tid, SIGUSR1));
sleep (1);
/* sigwait should wake up for SIGUSR1 */
ASSERT(sigcounts[SIGUSR1] == 1);
/* Add SIGHUP to the waiters pending signals. */
CHECKr(pthread_kill (tid, SIGUSR1));
/* Release the waiter thread and allow him to run. */
CHECKe(pthread_mutex_unlock (&waiter_mutex));
sleep (1);
/* sigwait should return for pending SIGUSR1 */
ASSERT(sigcounts[SIGUSR1] == 2);
#if 0
/*
* Verify that we can still kill the process for a signal
* not being waited on by sigwait.
*/
CHECKe(kill(getpid(), SIGPIPE));
PANIC("SIGPIPE did not terminate process");
/*
* Wait for the thread to finish.
*/
CHECKr(pthread_join (tid, NULL));
#endif
SUCCEED;
}
|
