tests/test-pthread-mutex-type.c

   1 /* Test of locking in multithreaded situations.
   2    Copyright (C) 2024-2025 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2024.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include <pthread.h>
  23
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27
  28 #include "macros.h"
  29
  30 /* Returns the effective type of a lock.  */
  31 static const char *
  32 get_effective_type (pthread_mutex_t *lock)
  33 {
  34   /* Lock once.  */
  35   ASSERT (pthread_mutex_lock (lock) == 0);
  36
  37   /* Try to lock a second time.  */
  38   int err = pthread_mutex_trylock (lock);
  39   if (err == 0)
  40     return "RECURSIVE";
  41   if (err == EBUSY)
  42     return "NORMAL";
  43
  44   /* We can't really check whether the lock is effectively ERRORCHECK, without
  45      risking a deadlock.  */
  46
  47   return "unknown!";
  48 }
  49
  50 int
  51 main ()
  52 {
  53   /* Find the effective type of a NORMAL lock.  */
  54   const char *type_normal;
  55   {
  56     pthread_mutex_t lock;
  57     pthread_mutexattr_t attr;
  58     ASSERT (pthread_mutexattr_init (&attr) == 0);
  59     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL) == 0);
  60     ASSERT (pthread_mutex_init (&lock, &attr) == 0);
  61     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
  62     type_normal = get_effective_type (&lock);
  63   }
  64
  65   /* Find the effective type of an ERRORCHECK lock.  */
  66   const char *type_errorcheck;
  67   {
  68     pthread_mutex_t lock;
  69     pthread_mutexattr_t attr;
  70     ASSERT (pthread_mutexattr_init (&attr) == 0);
  71     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ERRORCHECK) == 0);
  72     ASSERT (pthread_mutex_init (&lock, &attr) == 0);
  73     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
  74     type_errorcheck = get_effective_type (&lock);
  75   }
  76
  77   /* Find the effective type of a RECURSIVE lock.  */
  78   const char *type_recursive;
  79   {
  80     pthread_mutex_t lock;
  81     pthread_mutexattr_t attr;
  82     ASSERT (pthread_mutexattr_init (&attr) == 0);
  83     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
  84     ASSERT (pthread_mutex_init (&lock, &attr) == 0);
  85     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
  86     type_recursive = get_effective_type (&lock);
  87   }
  88
  89   /* Find the effective type of a DEFAULT lock.  */
  90   const char *type_default;
  91   {
  92     pthread_mutex_t lock;
  93     pthread_mutexattr_t attr;
  94     ASSERT (pthread_mutexattr_init (&attr) == 0);
  95     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_DEFAULT) == 0);
  96     ASSERT (pthread_mutex_init (&lock, &attr) == 0);
  97     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
  98     type_default = get_effective_type (&lock);
  99   }
 100
 101   /* Find the effective type of a default-initialized lock.  */
 102   const char *type_def;
 103   {
 104     pthread_mutex_t lock;
 105     ASSERT (pthread_mutex_init (&lock, NULL) == 0);
 106     type_def = get_effective_type (&lock);
 107   }
 108
 109   printf ("PTHREAD_MUTEX_NORMAL     -> type = %s\n", type_normal);
 110   printf ("PTHREAD_MUTEX_ERRORCHECK -> type = %s\n", type_errorcheck);
 111   printf ("PTHREAD_MUTEX_RECURSIVE  -> type = %s\n", type_recursive);
 112   printf ("PTHREAD_MUTEX_DEFAULT    -> type = %s\n", type_default);
 113   printf ("Default                  -> type = %s\n", type_def);
 114
 115   ASSERT (strcmp (type_normal,        "NORMAL") == 0);
 116   ASSERT (strcmp (type_errorcheck,    "NORMAL") == 0);
 117   ASSERT (strcmp (type_recursive,     "RECURSIVE") == 0);
 118
 119   ASSERT (strcmp (type_default, type_def) == 0);
 120
 121   /* This is not required by POSIX, but happens to be the case on all
 122      platforms.  */
 123   ASSERT (strcmp (type_default,       "NORMAL") == 0);
 124   ASSERT (strcmp (type_def,           "NORMAL") == 0);
 125
 126   return test_exit_status;
 127 }