1 /* C11 threads trylock mutex tests.
2 Copyright (C) 2018-2022 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. */
26 static mtx_t mutex;
27
28 /* Shared counter to check possible race conditions. */
29 static char shrd_counter;
30
31 /* Function to choose an action to do, depending on mtx_trylock
32 return value. */
33 static inline void
choose_action(int action,char * thread_name)34 choose_action (int action, char* thread_name)
35 {
36 switch (action)
37 {
38 case thrd_success:
39 ++shrd_counter;
40
41 if (mtx_unlock (&mutex) != thrd_success)
42 FAIL_EXIT1 ("mtx_unlock failed");
43 break;
44
45 case thrd_busy:
46 break;
47
48 case thrd_error:
49 FAIL_EXIT1 ("%s lock error", thread_name);
50 break;
51 }
52 }
53
54 static int
child_add(void * arg)55 child_add (void *arg)
56 {
57 char child_name[] = "child";
58
59 /* Try to lock mutex. */
60 choose_action (mtx_trylock (&mutex), child_name);
61
62 thrd_exit (thrd_success);
63 }
64
65 static int
do_test(void)66 do_test (void)
67 {
68 thrd_t id;
69 char parent_name[] = "parent";
70
71 if (mtx_init (&mutex, mtx_timed) != thrd_success)
72 FAIL_EXIT1 ("mtx_init failed");
73
74 if (thrd_create (&id, child_add, NULL) != thrd_success)
75 FAIL_EXIT1 ("thrd_create failed");
76
77 choose_action (mtx_trylock (&mutex), parent_name);
78
79 if (thrd_join (id, NULL) != thrd_success)
80 FAIL_EXIT1 ("thrd_join failed");
81
82 if (shrd_counter != 2 && shrd_counter != 1)
83 FAIL_EXIT1 ("shrd_counter != {1,2} (%d)", shrd_counter);
84
85 mtx_destroy (&mutex);
86
87 return 0;
88 }
89
90 #include <support/test-driver.c>
91