nptl/tst-mtx-trylock.c

   1 /* C11 threads trylock mutex tests.
   2    Copyright (C) 2018-2020 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
  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
  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
  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>