pthread-mutex: Add tests.

* tests/test-pthread-mutex.c: New file, based on tests/test-lock.c and
tests/test-mtx.c.
* modules/pthread-mutex-tests: New file.

ChangeLog

@@ -1,3 +1,10 @@
+2019-07-14  Bruno Haible  <bruno@clisp.org>
+
+	pthread-mutex: Add tests.
+	* tests/test-pthread-mutex.c: New file, based on tests/test-lock.c and
+	tests/test-mtx.c.
+	* modules/pthread-mutex-tests: New file.
+
 2019-07-14  Bruno Haible  <bruno@clisp.org>
 
 	pthread-once: Add tests.

modules/pthread-mutex-tests

@@ -0,0 +1,14 @@
+Files:
+tests/test-pthread-mutex.c
+tests/macros.h
+
+Depends-on:
+pthread-thread
+sched_yield
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-pthread-mutex
+check_PROGRAMS += test-pthread-mutex
+test_pthread_mutex_LDADD = $(LDADD) @LIBMULTITHREAD@ @YIELD_LIB@

tests/test-pthread-mutex.c

@@ -0,0 +1,524 @@
+/* Test of locking in multithreaded situations.
+   Copyright (C) 2005, 2008-2019 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2005.  */
+
+#include <config.h>
+
+#if USE_POSIX_THREADS || USE_WINDOWS_THREADS
+
+/* Whether to enable locking.
+   Uncomment this to get a test program without locking, to verify that
+   it crashes.  */
+#define ENABLE_LOCKING 1
+
+/* Which tests to perform.
+   Uncomment some of these, to verify that all tests crash if no locking
+   is enabled.  */
+#define DO_TEST_LOCK 1
+#define DO_TEST_RECURSIVE_LOCK 1
+
+/* Whether to help the scheduler through explicit sched_yield().
+   Uncomment this to see if the operating system has a fair scheduler.  */
+#define EXPLICIT_YIELD 1
+
+/* Whether to use 'volatile' on some variables that communicate information
+   between threads.  If set to 0, a semaphore or a lock is used to protect
+   these variables.  If set to 1, 'volatile' is used; this is theoretically
+   equivalent but can lead to much slower execution (e.g. 30x slower total
+   run time on a 40-core machine), because 'volatile' does not imply any
+   synchronization/communication between different CPUs.  */
+#define USE_VOLATILE 0
+
+#if USE_POSIX_THREADS && HAVE_SEMAPHORE_H
+/* Whether to use a semaphore to communicate information between threads.
+   If set to 0, a lock is used. If set to 1, a semaphore is used.
+   Uncomment this to reduce the dependencies of this test.  */
+# define USE_SEMAPHORE 1
+/* Mac OS X provides only named semaphores (sem_open); its facility for
+   unnamed semaphores (sem_init) does not work.  */
+# if defined __APPLE__ && defined __MACH__
+#  define USE_NAMED_SEMAPHORE 1
+# else
+#  define USE_UNNAMED_SEMAPHORE 1
+# endif
+#endif
+
+/* Whether to print debugging messages.  */
+#define ENABLE_DEBUGGING 0
+
+/* Number of simultaneous threads.  */
+#define THREAD_COUNT 10
+
+/* Number of operations performed in each thread.
+   This is quite high, because with a smaller count, say 5000, we often get
+   an "OK" result even without ENABLE_LOCKING (on Linux/x86).  */
+#define REPEAT_COUNT 50000
+
+#include <pthread.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if EXPLICIT_YIELD
+# include <sched.h>
+#endif
+
+#if USE_SEMAPHORE
+# include <errno.h>
+# include <fcntl.h>
+# include <semaphore.h>
+# include <unistd.h>
+#endif
+
+#if HAVE_DECL_ALARM
+# include <signal.h>
+# include <unistd.h>
+#endif
+
+#include "macros.h"
+
+#if ENABLE_DEBUGGING
+# define dbgprintf printf
+#else
+# define dbgprintf if (0) printf
+#endif
+
+#if EXPLICIT_YIELD
+# define yield() sched_yield ()
+#else
+# define yield()
+#endif
+
+#if USE_VOLATILE
+struct atomic_int {
+  volatile int value;
+};
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+}
+static int
+get_atomic_int_value (struct atomic_int *ai)
+{
+  return ai->value;
+}
+static void
+set_atomic_int_value (struct atomic_int *ai, int new_value)
+{
+  ai->value = new_value;
+}
+#elif USE_SEMAPHORE
+/* This atomic_int implementation can only support the values 0 and 1.
+   It is initially 0 and can be set to 1 only once.  */
+# if USE_UNNAMED_SEMAPHORE
+struct atomic_int {
+  sem_t semaphore;
+};
+#define atomic_int_semaphore(ai) (&(ai)->semaphore)
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+  sem_init (&ai->semaphore, 0, 0);
+}
+# endif
+# if USE_NAMED_SEMAPHORE
+struct atomic_int {
+  sem_t *semaphore;
+};
+#define atomic_int_semaphore(ai) ((ai)->semaphore)
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+  sem_t *s;
+  unsigned int count;
+  for (count = 0; ; count++)
+    {
+      char name[80];
+      /* Use getpid() in the name, so that different processes running at the
+         same time will not interfere.  Use ai in the name, so that different
+         atomic_int in the same process will not interfere.  Use a count in
+         the name, so that even in the (unlikely) case that a semaphore with
+         the specified name already exists, we can try a different name.  */
+      sprintf (name, "test-lock-%lu-%p-%u",
+               (unsigned long) getpid (), ai, count);
+      s = sem_open (name, O_CREAT | O_EXCL, 0600, 0);
+      if (s == SEM_FAILED)
+        {
+          if (errno == EEXIST)
+            /* Retry with a different name.  */
+            continue;
+          else
+            {
+              perror ("sem_open failed");
+              abort ();
+            }
+        }
+      else
+        {
+          /* Try not to leave a semaphore hanging around on the file system
+             eternally, if we can avoid it.  */
+          sem_unlink (name);
+          break;
+        }
+    }
+  ai->semaphore = s;
+}
+# endif
+static int
+get_atomic_int_value (struct atomic_int *ai)
+{
+  if (sem_trywait (atomic_int_semaphore (ai)) == 0)
+    {
+      if (sem_post (atomic_int_semaphore (ai)))
+        abort ();
+      return 1;
+    }
+  else if (errno == EAGAIN)
+    return 0;
+  else
+    abort ();
+}
+static void
+set_atomic_int_value (struct atomic_int *ai, int new_value)
+{
+  if (new_value == 0)
+    /* It's already initialized with 0.  */
+    return;
+  /* To set the value 1: */
+  if (sem_post (atomic_int_semaphore (ai)))
+    abort ();
+}
+#else
+struct atomic_int {
+  pthread_mutex_t lock;
+  int value;
+};
+static void
+init_atomic_int (struct atomic_int *ai)
+{
+  pthread_mutexattr_t attr;
+
+  ASSERT (pthread_mutexattr_init (&attr) == 0);
+  ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL) == 0);
+  ASSERT (pthread_mutex_init (&ai->lock, &attr) == 0);
+  ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+}
+static int
+get_atomic_int_value (struct atomic_int *ai)
+{
+  ASSERT (pthread_mutex_lock (&ai->lock) == 0);
+  int ret = ai->value;
+  ASSERT (pthread_mutex_unlock (&ai->lock) == 0);
+  return ret;
+}
+static void
+set_atomic_int_value (struct atomic_int *ai, int new_value)
+{
+  ASSERT (pthread_mutex_lock (&ai->lock) == 0);
+  ai->value = new_value;
+  ASSERT (pthread_mutex_unlock (&ai->lock) == 0);
+}
+#endif
+
+/* Returns a reference to the current thread as a pointer, for debugging.  */
+#if defined __MVS__
+  /* On IBM z/OS, pthread_t is a struct with an 8-byte '__' field.
+     The first three bytes of this field appear to uniquely identify a
+     pthread_t, though not necessarily representing a pointer.  */
+# define pthread_self_pointer() (*((void **) pthread_self ().__))
+#else
+# define pthread_self_pointer() ((void *) (uintptr_t) pthread_self ())
+#endif
+
+#define ACCOUNT_COUNT 4
+
+static int account[ACCOUNT_COUNT];
+
+static int
+random_account (void)
+{
+  return ((unsigned int) rand () >> 3) % ACCOUNT_COUNT;
+}
+
+static void
+check_accounts (void)
+{
+  int i, sum;
+
+  sum = 0;
+  for (i = 0; i < ACCOUNT_COUNT; i++)
+    sum += account[i];
+  if (sum != ACCOUNT_COUNT * 1000)
+    abort ();
+}
+
+
+/* ------------------- Test normal (non-recursive) locks ------------------- */
+
+/* Test normal locks by having several bank accounts and several threads
+   which shuffle around money between the accounts and another thread
+   checking that all the money is still there.  */
+
+static pthread_mutex_t my_lock;
+
+static void *
+lock_mutator_thread (void *arg)
+{
+  int repeat;
+
+  for (repeat = REPEAT_COUNT; repeat > 0; repeat--)
+    {
+      int i1, i2, value;
+
+      dbgprintf ("Mutator %p before lock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_lock (&my_lock) == 0);
+      dbgprintf ("Mutator %p after  lock\n", pthread_self_pointer ());
+
+      i1 = random_account ();
+      i2 = random_account ();
+      value = ((unsigned int) rand () >> 3) % 10;
+      account[i1] += value;
+      account[i2] -= value;
+
+      dbgprintf ("Mutator %p before unlock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_unlock (&my_lock) == 0);
+      dbgprintf ("Mutator %p after  unlock\n", pthread_self_pointer ());
+
+      dbgprintf ("Mutator %p before check lock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_lock (&my_lock) == 0);
+      check_accounts ();
+      ASSERT (pthread_mutex_unlock (&my_lock) == 0);
+      dbgprintf ("Mutator %p after  check unlock\n", pthread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Mutator %p dying.\n", pthread_self_pointer ());
+  return NULL;
+}
+
+static struct atomic_int lock_checker_done;
+
+static void *
+lock_checker_thread (void *arg)
+{
+  while (get_atomic_int_value (&lock_checker_done) == 0)
+    {
+      dbgprintf ("Checker %p before check lock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_lock (&my_lock) == 0);
+      check_accounts ();
+      ASSERT (pthread_mutex_unlock (&my_lock) == 0);
+      dbgprintf ("Checker %p after  check unlock\n", pthread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Checker %p dying.\n", pthread_self_pointer ());
+  return NULL;
+}
+
+static void
+test_pthread_mutex_normal (void)
+{
+  int i;
+  pthread_t checkerthread;
+  pthread_t threads[THREAD_COUNT];
+
+  /* Initialization.  */
+  for (i = 0; i < ACCOUNT_COUNT; i++)
+    account[i] = 1000;
+  init_atomic_int (&lock_checker_done);
+  set_atomic_int_value (&lock_checker_done, 0);
+
+  /* Spawn the threads.  */
+  ASSERT (pthread_create (&checkerthread, NULL, lock_checker_thread, NULL)
+          == 0);
+  for (i = 0; i < THREAD_COUNT; i++)
+    ASSERT (pthread_create (&threads[i], NULL, lock_mutator_thread, NULL) == 0);
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    ASSERT (pthread_join (threads[i], NULL) == 0);
+  set_atomic_int_value (&lock_checker_done, 1);
+  ASSERT (pthread_join (checkerthread, NULL) == 0);
+  check_accounts ();
+}
+
+
+/* -------------------------- Test recursive locks -------------------------- */
+
+/* Test recursive locks by having several bank accounts and several threads
+   which shuffle around money between the accounts (recursively) and another
+   thread checking that all the money is still there.  */
+
+static pthread_mutex_t my_reclock;
+
+static void
+recshuffle (void)
+{
+  int i1, i2, value;
+
+  dbgprintf ("Mutator %p before lock\n", pthread_self_pointer ());
+  ASSERT (pthread_mutex_lock (&my_reclock) == 0);
+  dbgprintf ("Mutator %p after  lock\n", pthread_self_pointer ());
+
+  i1 = random_account ();
+  i2 = random_account ();
+  value = ((unsigned int) rand () >> 3) % 10;
+  account[i1] += value;
+  account[i2] -= value;
+
+  /* Recursive with probability 0.5.  */
+  if (((unsigned int) rand () >> 3) % 2)
+    recshuffle ();
+
+  dbgprintf ("Mutator %p before unlock\n", pthread_self_pointer ());
+  ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
+  dbgprintf ("Mutator %p after  unlock\n", pthread_self_pointer ());
+}
+
+static void *
+reclock_mutator_thread (void *arg)
+{
+  int repeat;
+
+  for (repeat = REPEAT_COUNT; repeat > 0; repeat--)
+    {
+      recshuffle ();
+
+      dbgprintf ("Mutator %p before check lock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_lock (&my_reclock) == 0);
+      check_accounts ();
+      ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
+      dbgprintf ("Mutator %p after  check unlock\n", pthread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Mutator %p dying.\n", pthread_self_pointer ());
+  return NULL;
+}
+
+static struct atomic_int reclock_checker_done;
+
+static void *
+reclock_checker_thread (void *arg)
+{
+  while (get_atomic_int_value (&reclock_checker_done) == 0)
+    {
+      dbgprintf ("Checker %p before check lock\n", pthread_self_pointer ());
+      ASSERT (pthread_mutex_lock (&my_reclock) == 0);
+      check_accounts ();
+      ASSERT (pthread_mutex_unlock (&my_reclock) == 0);
+      dbgprintf ("Checker %p after  check unlock\n", pthread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Checker %p dying.\n", pthread_self_pointer ());
+  return NULL;
+}
+
+static void
+test_pthread_mutex_recursive (void)
+{
+  int i;
+  pthread_t checkerthread;
+  pthread_t threads[THREAD_COUNT];
+
+  /* Initialization.  */
+  for (i = 0; i < ACCOUNT_COUNT; i++)
+    account[i] = 1000;
+  init_atomic_int (&reclock_checker_done);
+  set_atomic_int_value (&reclock_checker_done, 0);
+
+  /* Spawn the threads.  */
+  ASSERT (pthread_create (&checkerthread, NULL, reclock_checker_thread, NULL)
+          == 0);
+  for (i = 0; i < THREAD_COUNT; i++)
+    ASSERT (pthread_create (&threads[i], NULL, reclock_mutator_thread, NULL)
+            == 0);
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    ASSERT (pthread_join (threads[i], NULL) == 0);
+  set_atomic_int_value (&reclock_checker_done, 1);
+  ASSERT (pthread_join (checkerthread, NULL) == 0);
+  check_accounts ();
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+int
+main ()
+{
+#if HAVE_DECL_ALARM
+  /* Declare failure if test takes too long, by using default abort
+     caused by SIGALRM.  */
+  int alarm_value = 600;
+  signal (SIGALRM, SIG_DFL);
+  alarm (alarm_value);
+#endif
+
+  {
+    pthread_mutexattr_t attr;
+
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL) == 0);
+    ASSERT (pthread_mutex_init (&my_lock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+  }
+
+  {
+    pthread_mutexattr_t attr;
+
+    ASSERT (pthread_mutexattr_init (&attr) == 0);
+    ASSERT (pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
+    ASSERT (pthread_mutex_init (&my_reclock, &attr) == 0);
+    ASSERT (pthread_mutexattr_destroy (&attr) == 0);
+  }
+
+#if DO_TEST_LOCK
+  printf ("Starting test_pthread_mutex_normal ..."); fflush (stdout);
+  test_pthread_mutex_normal ();
+  printf (" OK\n"); fflush (stdout);
+#endif
+#if DO_TEST_RECURSIVE_LOCK
+  printf ("Starting test_pthread_mutex_recursive ..."); fflush (stdout);
+  test_pthread_mutex_recursive ();
+  printf (" OK\n"); fflush (stdout);
+#endif
+
+  return 0;
+}
+
+#else
+
+/* No multithreading available.  */
+
+#include <stdio.h>
+
+int
+main ()
+{
+  fputs ("Skipping test: multithreading not enabled\n", stderr);
+  return 77;
+}
+
+#endif