1 /*
2 * Copyright (C) 2010 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 /* This program is used to test that sem_post() will wake up all
30 * threads that are waiting on a single semaphore, and not all of
31 * them.
32 */
33
34 #include <pthread.h>
35 #include <semaphore.h>
36 #include <stdio.h>
37 #include <errno.h>
38 #include <string.h>
39 #include <unistd.h>
40
41 static sem_t semaphore;
42
43 /* Thread function, just wait for the semaphore */
44 static void*
thread_func(void * arg)45 thread_func(void* arg)
46 {
47 sem_t *psem = (sem_t *)arg;
48 void *me = (void *)pthread_self();
49 printf("thread %p waiting\n", me);
50 sem_wait(psem);
51 printf("thread %p exiting\n", me);
52 return me;
53 }
54
55 #define MAX_THREADS 50
56
main(void)57 int main(void)
58 {
59 pthread_t t[MAX_THREADS];
60 int nn, value;
61
62 /* Initialize to 1, first thread will exit immediately.
63 * this is used to exercize more of the semaphore code path */
64 if ( sem_init( &semaphore, 0, 1 ) < 0 ) {
65 printf( "Could not initialize semaphore: %s\n", strerror(errno) );
66 return 1;
67 }
68
69 for ( nn = 0; nn < MAX_THREADS; nn++ ) {
70 if ( pthread_create( &t[nn], NULL, thread_func, &semaphore ) < 0 ) {
71 printf("Could not create thread %d: %s\n", nn+1, strerror(errno) );
72 return 2;
73 }
74 }
75 sleep( 1 );
76
77 for (nn = 0; nn < MAX_THREADS; nn++) {
78 sem_post(&semaphore);
79 }
80
81 for ( nn = 0; nn < MAX_THREADS; nn++) {
82 void* result;
83 pthread_join(t[nn], &result);
84 if (result != (void*)t[nn]) {
85 printf("Thread %p joined but returned %p\n", (void*)t[nn], result);
86 }
87 }
88
89 if (sem_getvalue(&semaphore, &value) < 0) {
90 printf("Could not get semaphore value: %s\n", strerror(errno));
91 return 3;
92 }
93 if (value != 1) {
94 printf("Error: Semaphore value = %d\n", value);
95 return 4;
96 }
97 return 0;
98 }
99