1  /* C11 threads timed mutex tests.
       2     Copyright (C) 2018-2023 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  #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  /* Maximum amount of time waiting for mutex.  */
      32  static struct timespec wait_time;
      33  
      34  /* Function to choose an action to do, depending on mtx_timedlock
      35     return value.  */
      36  static inline void
      37  choose_action (int action, char* thread_name)
      38  {
      39    switch (action)
      40      {
      41        case thrd_success:
      42          ++shrd_counter;
      43  
      44  	if (mtx_unlock (&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  
      57  static int
      58  child_add (void *arg)
      59  {
      60    char child_name[] = "child";
      61  
      62    /* Try to lock mutex.  */
      63    choose_action (mtx_timedlock (&mutex, &wait_time), child_name);
      64    thrd_exit (thrd_success);
      65  }
      66  
      67  static int
      68  do_test (void)
      69  {
      70    thrd_t id;
      71    char parent_name[] = "parent";
      72  
      73    if (mtx_init (&mutex, mtx_timed) != thrd_success)
      74      FAIL_EXIT1 ("mtx_init failed");
      75  
      76    if (clock_gettime (CLOCK_REALTIME, &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 (&id, child_add, NULL) != thrd_success)
      88      FAIL_EXIT1 ("thrd_create failed");
      89  
      90    choose_action (mtx_timedlock (&mutex, &wait_time), parent_name);
      91  
      92    if (thrd_join (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);
      99  
     100    return 0;
     101  }
     102  
     103  #include <support/test-driver.c>