tests/test-pthread-mutex.c

   1 /* Test of locking in multithreaded situations.
   2    Copyright (C) 2005, 2008-2024 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>, 2005.  */
  18
  19 #include <config.h>
  20
  21 #if USE_ISOC_THREADS || USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS || USE_WINDOWS_THREADS
  22
  23 /* Whether to enable locking.
  24    Uncomment this to get a test program without locking, to verify that
  25    it crashes.  */
  26 #define ENABLE_LOCKING 1
  27
  28 /* Which tests to perform.
  29    Uncomment some of these, to verify that all tests crash if no locking
  30    is enabled.  */
  31 #define DO_TEST_LOCK 1
  32 #define DO_TEST_RECURSIVE_LOCK 1
  33
  34 /* Whether to help the scheduler through explicit sched_yield().
  35    Uncomment this to see if the operating system has a fair scheduler.  */
  36 #define EXPLICIT_YIELD 1
  37
  38 /* Whether to print debugging messages.  */
  39 #define ENABLE_DEBUGGING 0
  40
  41 /* Number of simultaneous threads.  */
  42 #define THREAD_COUNT 10
  43
  44 /* Number of operations performed in each thread.
  45    This is quite high, because with a smaller count, say 5000, we often get
  46    an "OK" result even without ENABLE_LOCKING (on Linux/x86).  */
  47 #define REPEAT_COUNT 50000
  48
  49 #include <pthread.h>
  50 #include <stdint.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54
  55 #if EXPLICIT_YIELD
  56 # include <sched.h>
  57 #endif
  58
  59 #if HAVE_DECL_ALARM
  60 # include <signal.h>
  61 # include <unistd.h>
  62 #endif
  63
  64 #include "macros.h"
  65 #include "atomic-int-posix.h"
  66
  67 #if ENABLE_DEBUGGING
  68 # define dbgprintf printf
  69 #else
  70 # define dbgprintf if (0) printf
  71 #endif
  72
  73 #if EXPLICIT_YIELD
  74 # define yield() sched_yield ()
  75 #else
  76 # define yield()
  77 #endif
  78
  79 /* Returns a reference to the current thread as a pointer, for debugging.  */
  80 #if defined __MVS__
  81   /* On IBM z/OS, pthread_t is a struct with an 8-byte '__' field.
  82      The first three bytes of this field appear to uniquely identify a
  83      pthread_t, though not necessarily representing a pointer.  */
  84 # define pthread_self_pointer() (*((void **) pthread_self ().__))
  85 #else
  86 # define pthread_self_pointer() ((void *) (uintptr_t) pthread_self ())
  87 #endif
  88
  89 #define ACCOUNT_COUNT 4
  90
  91 static int account[ACCOUNT_COUNT];
  92
  93 static int
  94 random_account (void)
  95 {
  96   return ((unsigned long) random () >> 3) % ACCOUNT_COUNT;
  97 }
  98
  99 static void
 100 check_accounts (void)
 101 {
 102   int i, sum;
 103
 104   sum = 0;
 105   for (i = 0; i < ACCOUNT_COUNT; i++)
 106     sum += account[i];
 107   if (sum != ACCOUNT_COUNT * 1000)
 108     abort ();
 109 }
 110
 111
 112 /* ------------------- Test normal (non-recursive) locks ------------------- */
 113
 114 /* Test normal locks by having several bank accounts and several threads
 115    which shuffle around money between the accounts and another thread
 116    checking that all the money is still there.  */
 117
 118 static pthread_mutex_t my_lock;
 119
 120 static void *
 121 lock_mutator_thread (void *arg)
 122 {
 123   int repeat;
 124
 125   for (repeat = REPEAT_COUNT; repeat > 0; repeat--)
 126     {
 127       int i1, i2, value;
 128
 129       dbgprintf ("Mutator %p before lock\n", pthread_self_pointer ());
 130       ASSERT (pthread_mutex_lock (&my_lock) == 0);
 131       dbgprintf ("Mutator %p after  lock\n", pthread_self_pointer ());
 132
 133       i1 = random_account ();
 134       i2 = random_account ();
 135       value = ((unsigned long) random () >> 3) % 10;
 136       account[i1] += value;
 137       account[i2] -= value;
 138
 139       dbgprintf ("Mutator %p before unlock\n", pthread_self_pointer ());
 140       ASSERT (pthread_mutex_unlock (&my_lock) == 0);
 141       dbgprintf ("Mutator %p after  unlock\n", pthread_self_pointer ());
 142
 143       dbgprintf ("Mutator %p before check lock\n", pthread_self_pointer ());
 144       ASSERT (pthread_mutex_lock (&my_lock) == 0);
 145       check_accounts ();
 146       ASSERT (pthread_mutex_unlock (&my_lock) == 0);
 147       dbgprintf ("Mutator %p after  check unlock\n", pthread_self_pointer ());
 148
 149       yield ();
 150     }
 151
 152   dbgprintf ("Mutator %p dying.\n", pthread_self_pointer ());
 153   return NULL;
 154 }
 155
 156 static struct atomic_int lock_checker_done;
 157
 158 static void *
 159 lock_checker_thread (void *arg)
 160 {
 161   while (get_atomic_int_value (&lock_checker_done) == 0)
 162     {
 163       dbgprintf ("Checker %p before check lock\n", pthread_self_pointer ());
 164       ASSERT (pthread_mutex_lock (&my_lock) == 0);
 165       check_accounts ();
 166       ASSERT (pthread_mutex_unlock (&my_lock) == 0);
 167       dbgprintf ("Checker %p after  check unlock\n", pthread_self_pointer ());
 168
 169       yield ();
 170     }
 171
 172   dbgprintf ("Checker %p dying.\n", pthread_self_pointer ());
 173   return NULL;
 174 }
 175
 176 static void
 177 test_pthread_mutex_normal (void)
 178 {
 179   int i;
 180   pthread_t checkerthread;
 181   pthread_t threads[THREAD_COUNT];
 182
 183   /* Initialization.  */
 184   for (i = 0; i < ACCOUNT_COUNT; i++)
 185     account[i] = 1000;
 186   init_atomic_int (&lock_checker_done);
 187   set_atomic_int_value (&lock_checker_done, 0);
 188
 189   /* Spawn the threads.  */
 190   ASSERT (pthread_create (&checkerthread, NULL, lock_checker_thread, NULL)
 191           == 0);
 192   for (i = 0; i < THREAD_COUNT; i++)
 193     ASSERT (pthread_create (&threads[i], NULL, lock_mutator_thread, NULL) == 0);
 194
 195   /* Wait for the threads to terminate.  */
 196   for (i = 0; i < THREAD_COUNT; i++)
 197     ASSERT (pthread_join (threads[i], NULL) == 0);
 198   set_atomic_int_value (&lock_checker_done, 1);
 199   ASSERT (pthread_join (checkerthread, NULL) == 0);
 200   check_accounts ();
 201 }
 202
 203
 204 /* -------------------------- Test recursive locks -------------------------- */
 205
 206 /* Test recursive locks by having several bank accounts and several threads
 207    which shuffle around money between the accounts (recursively) and another
 208    thread checking that all the money is still there.  */
 209
 210 static pthread_mutex_t my_reclock;
 211
 212 static void
 213 recshuffle (void)
 214 {
 215   int i1, i2, value;
 216
 217   dbgprintf ("Mutator %p before lock\n", pthread_self_pointer ());
 218   ASSERT (pthread_mutex_lock (&my_reclock) == 0);
 219   dbgprintf ("Mutator %p after  lock\n", pthread_self_pointer ());
 220
 221   i1 = random_account ();
 222   i2 = random_account ();
 223   value = ((unsigned long) random () >> 3) % 10;
 224   account[i1] += value;
 225   account[i2] -= value;
 226
 227   /* Recursive with probability 0.5.  */
 228   if (((unsigned long) random () >> 3) % 2)
 229     recshuffle ();
 230
 231   dbgprintf ("Mutator %p before unlock\n", pthread_self_pointer ());
 232   ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
 233   dbgprintf ("Mutator %p after  unlock\n", pthread_self_pointer ());
 234 }
 235
 236 static void *
 237 reclock_mutator_thread (void *arg)
 238 {
 239   int repeat;
 240
 241   for (repeat = REPEAT_COUNT; repeat > 0; repeat--)
 242     {
 243       recshuffle ();
 244
 245       dbgprintf ("Mutator %p before check lock\n", pthread_self_pointer ());
 246       ASSERT (pthread_mutex_lock (&my_reclock) == 0);
 247       check_accounts ();
 248       ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
 249       dbgprintf ("Mutator %p after  check unlock\n", pthread_self_pointer ());
 250
 251       yield ();
 252     }
 253
 254   dbgprintf ("Mutator %p dying.\n", pthread_self_pointer ());
 255   return NULL;
 256 }
 257
 258 static struct atomic_int reclock_checker_done;
 259
 260 static void *
 261 reclock_checker_thread (void *arg)
 262 {
 263   while (get_atomic_int_value (&reclock_checker_done) == 0)
 264     {
 265       dbgprintf ("Checker %p before check lock\n", pthread_self_pointer ());
 266       ASSERT (pthread_mutex_lock (&my_reclock) == 0);
 267       check_accounts ();
 268       ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
 269       dbgprintf ("Checker %p after  check unlock\n", pthread_self_pointer ());
 270
 271       yield ();
 272     }
 273
 274   dbgprintf ("Checker %p dying.\n", pthread_self_pointer ());
 275   return NULL;
 276 }
 277
 278 static void
 279 test_pthread_mutex_recursive (void)
 280 {
 281   int i;
 282   pthread_t checkerthread;
 283   pthread_t threads[THREAD_COUNT];
 284
 285   /* Initialization.  */
 286   for (i = 0; i < ACCOUNT_COUNT; i++)
 287     account[i] = 1000;
 288   init_atomic_int (&reclock_checker_done);
 289   set_atomic_int_value (&reclock_checker_done, 0);
 290
 291   /* Spawn the threads.  */
 292   ASSERT (pthread_create (&checkerthread, NULL, reclock_checker_thread, NULL)
 293           == 0);
 294   for (i = 0; i < THREAD_COUNT; i++)
 295     ASSERT (pthread_create (&threads[i], NULL, reclock_mutator_thread, NULL)
 296             == 0);
 297
 298   /* Wait for the threads to terminate.  */
 299   for (i = 0; i < THREAD_COUNT; i++)
 300     ASSERT (pthread_join (threads[i], NULL) == 0);
 301   set_atomic_int_value (&reclock_checker_done, 1);
 302   ASSERT (pthread_join (checkerthread, NULL) == 0);
 303   check_accounts ();
 304 }
 305
 306
 307 /* -------------------------------------------------------------------------- */
 308
 309 int
 310 main ()
 311 {
 312 #if HAVE_DECL_ALARM
 313   /* Declare failure if test takes too long, by using default abort
 314      caused by SIGALRM.  */
 315   int alarm_value = 600;
 316   signal (SIGALRM, SIG_DFL);
 317   alarm (alarm_value);
 318 #endif
 319
 320   {
 321     pthread_mutexattr_t attr;
 322
 323     ASSERT (pthread_mutexattr_init (&attr) == 0);
 324     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL) == 0);
 325     ASSERT (pthread_mutex_init (&my_lock, &attr) == 0);
 326     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
 327   }
 328
 329   {
 330     pthread_mutexattr_t attr;
 331
 332     ASSERT (pthread_mutexattr_init (&attr) == 0);
 333     ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
 334     ASSERT (pthread_mutex_init (&my_reclock, &attr) == 0);
 335     ASSERT (pthread_mutexattr_destroy (&attr) == 0);
 336   }
 337
 338 #if DO_TEST_LOCK
 339   printf ("Starting test_pthread_mutex_normal ..."); fflush (stdout);
 340   test_pthread_mutex_normal ();
 341   printf (" OK\n"); fflush (stdout);
 342 #endif
 343 #if DO_TEST_RECURSIVE_LOCK
 344   printf ("Starting test_pthread_mutex_recursive ..."); fflush (stdout);
 345   test_pthread_mutex_recursive ();
 346   printf (" OK\n"); fflush (stdout);
 347 #endif
 348
 349   return test_exit_status;
 350 }
 351
 352 #else
 353
 354 /* No multithreading available.  */
 355
 356 #include <stdio.h>
 357
 358 int
 359 main ()
 360 {
 361   fputs ("Skipping test: multithreading not enabled\n", stderr);
 362   return 77;
 363 }
 364
 365 #endif