1/* C11 threads timed mutex tests.
2 Copyright (C) 2018-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <threads.h>
20#include <stdio.h>
21#include <unistd.h>
22
23#include <support/check.h>
24
25/* Shared mutex between child and parent. */
26static mtx_t mutex;
27
28/* Shared counter to check possible race conditions. */
29static char shrd_counter;
30
31/* Maximum amount of time waiting for mutex. */
32static struct timespec wait_time;
33
34/* Function to choose an action to do, depending on mtx_timedlock
35 return value. */
36static inline void
37choose_action (int action, char* thread_name)
38{
39 switch (action)
40 {
41 case thrd_success:
42 ++shrd_counter;
43
44 if (mtx_unlock (mutex: &mutex) != thrd_success)
45 FAIL_EXIT1 ("mtx_unlock failed");
46 break;
47
48 case thrd_timedout:
49 break;
50
51 case thrd_error:
52 FAIL_EXIT1 ("%s lock error", thread_name);
53 break;
54 }
55}
56
57static int
58child_add (void *arg)
59{
60 char child_name[] = "child";
61
62 /* Try to lock mutex. */
63 choose_action (action: mtx_timedlock (mutex: &mutex, time_point: &wait_time), thread_name: child_name);
64 thrd_exit (res: thrd_success);
65}
66
67static int
68do_test (void)
69{
70 thrd_t id;
71 char parent_name[] = "parent";
72
73 if (mtx_init (mutex: &mutex, type: mtx_timed) != thrd_success)
74 FAIL_EXIT1 ("mtx_init failed");
75
76 if (clock_gettime (CLOCK_REALTIME, tp: &wait_time) != 0)
77 FAIL_EXIT1 ("clock_gettime failed");
78 /* Tiny amount of time, to assure that if any thread finds it busy.
79 It will receive thrd_timedout. */
80 wait_time.tv_nsec += 1;
81 if (wait_time.tv_nsec == 1000 * 1000 * 1000)
82 {
83 wait_time.tv_sec += 1;
84 wait_time.tv_nsec = 0;
85 }
86
87 if (thrd_create (thr: &id, func: child_add, NULL) != thrd_success)
88 FAIL_EXIT1 ("thrd_create failed");
89
90 choose_action (action: mtx_timedlock (mutex: &mutex, time_point: &wait_time), thread_name: parent_name);
91
92 if (thrd_join (thr: id, NULL) != thrd_success)
93 FAIL_EXIT1 ("thrd_join failed");
94
95 if (shrd_counter != 2 && shrd_counter != 1)
96 FAIL_EXIT1 ("shrd_counter != {1,2} (%d)", shrd_counter);
97
98 mtx_destroy (mutex: &mutex);
99
100 return 0;
101}
102
103#include <support/test-driver.c>
104

source code of glibc/sysdeps/pthread/tst-mtx-timedlock.c