1 /*
2 * Copyright (c) 2002, Intel Corporation. All rights reserved.
3 * Created by: bing.wei.liu REMOVE-THIS AT intel DOT com
4 * This file is licensed under the GPL license. For the full content
5 * of this license, see the COPYING file at the top level of this
6 * source tree.
7
8 * Test that pthread_mutex_trylock()
9 * is equivalent to pthread_mutex_lock() except that if the mutex object
10 * referenced by 'mutex' is currently locked (by any thread, including the
11 * current thread), the call shall return immediately.
12
13 * Steps:
14 * -- Initilize a mutex object
15 * -- Create a secondary thread and have it lock the mutex
16 * -- Within the main thread, try to lock the mutex using
17 pthread_mutex_trylock() and EBUSY is expected
18 * -- Have the secondary thread unlock the mutex
19 * -- Within the main thread, try to lock the mutex again
20 and expect a successful locking.
21 *
22 */
23
24 #include <pthread.h>
25 #include <stdio.h>
26 #include <errno.h>
27 #include <unistd.h>
28 #include "posixtest.h"
29
30 static void *func(void *parm);
31
32 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
33 static int t1_start = 0;
34 static int t1_pause = 1;
35
main(void)36 int main(void)
37 {
38 int i, rc;
39 pthread_t t1;
40
41 /* Create a secondary thread and wait until it has locked the mutex */
42 pthread_create(&t1, NULL, func, NULL);
43 while (!t1_start)
44 sleep(1);
45
46 /* Trylock the mutex and expect it returns EBUSY */
47 rc = pthread_mutex_trylock(&mutex);
48 if (rc != EBUSY) {
49 fprintf(stderr, "Expected %d(EBUSY), got %d\n", EBUSY, rc);
50 printf("Test FAILED\n");
51 return PTS_FAIL;
52 }
53
54 /* Allow the secondary thread to go ahead */
55 t1_pause = 0;
56
57 /* Trylock the mutex for N times */
58 for (i = 0; i < 5; i++) {
59 rc = pthread_mutex_trylock(&mutex);
60 if (rc == 0) {
61 pthread_mutex_unlock(&mutex);
62 break;
63 } else if (rc == EBUSY) {
64 sleep(1);
65 continue;
66 } else {
67 fprintf(stderr,
68 "Unexpected error code(%d) for pthread_mutex_lock()\n",
69 rc);
70 return PTS_UNRESOLVED;
71 }
72 }
73
74 /* Clean up */
75 pthread_join(t1, NULL);
76 pthread_mutex_destroy(&mutex);
77
78 if (i >= 5) {
79 fprintf(stderr,
80 "Have tried %d times but failed to get the mutex\n", i);
81 return PTS_UNRESOLVED;
82 }
83 printf("Test PASSED\n");
84 return PTS_PASS;
85 }
86
func(void * parm PTS_ATTRIBUTE_UNUSED)87 static void *func(void *parm PTS_ATTRIBUTE_UNUSED)
88 {
89 int rc;
90
91 if ((rc = pthread_mutex_lock(&mutex)) != 0) {
92 fprintf(stderr, "Error at pthread_mutex_lock(), rc=%d\n", rc);
93 pthread_exit((void *)PTS_UNRESOLVED);
94 }
95 t1_start = 1;
96
97 while (t1_pause)
98 sleep(1);
99
100 if ((rc = pthread_mutex_unlock(&mutex)) != 0) {
101 fprintf(stderr, "Error at pthread_mutex_unlock(), rc=%d\n", rc);
102 pthread_exit((void *)PTS_UNRESOLVED);
103 }
104
105 pthread_exit(0);
106 return (void *)(0);
107 }
108