1  /* Test recursive mutexes.
       2     Copyright (C) 2000-2023 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 *
      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
      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  }