1 /* Test recursive mutexes.
2    Copyright (C) 2000-2022 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 #define _GNU_SOURCE
20 
21 #include <pthread.h>
22 #include <assert.h>
23 #include <error.h>
24 #include <errno.h>
25 
26 #define THREADS 10
27 
28 int foo;
29 
30 void *
thr(void * arg)31 thr (void *arg)
32 {
33   int i;
34 
35   pthread_mutex_lock (arg);
36 
37   foo = pthread_self ();
38 
39   for (i = 0; i < 500; i++)
40     pthread_mutex_lock (arg);
41   for (i = 0; i < 500; i++)
42     pthread_mutex_unlock (arg);
43 
44   assert (foo == pthread_self ());
45 
46   pthread_mutex_unlock (arg);
47 
48   return 0;
49 }
50 
51 int
main(int argc,char ** argv)52 main (int argc, char **argv)
53 {
54   error_t err;
55   int i;
56   pthread_t tid[THREADS];
57   pthread_mutexattr_t mattr;
58   pthread_mutex_t mutex;
59 
60   err = pthread_mutexattr_init (&mattr);
61   if (err)
62     error (1, err, "pthread_mutexattr_init");
63 
64   err = pthread_mutexattr_settype (&mattr, PTHREAD_MUTEX_RECURSIVE);
65   if (err)
66     error (1, err, "pthread_mutexattr_settype");
67 
68   err = pthread_mutex_init (&mutex, &mattr);
69   if (err)
70     error (1, err, "pthread_mutex_init");
71 
72   err = pthread_mutexattr_destroy (&mattr);
73   if (err)
74     error (1, err, "pthread_mutexattr_destroy");
75 
76   pthread_mutex_lock (&mutex);
77   pthread_mutex_lock (&mutex);
78   pthread_mutex_unlock (&mutex);
79   pthread_mutex_unlock (&mutex);
80 
81   for (i = 0; i < THREADS; i++)
82     {
83       err = pthread_create (&tid[i], 0, thr, &mutex);
84       if (err)
85 	error (1, err, "pthread_create (%d)", i);
86     }
87 
88   for (i = 0; i < THREADS; i++)
89     {
90       void *ret;
91 
92       err = pthread_join (tid[i], &ret);
93       if (err)
94 	error (1, err, "pthread_join");
95 
96       assert (ret == 0);
97     }
98 
99   err = pthread_mutex_destroy (&mutex);
100   if (err)
101     error (1, err, "pthread_mutex_destroy");
102 
103   return 0;
104 }
105