1 files changed, 618 insertions, 0 deletions
diff --git a/gnulib-tests/test-lock.c b/gnulib-tests/test-lock.c
new file mode 100644
index 0000000..b52f7e0
--- /dev/null
+++ b/gnulib-tests/test-lock.c
@@ -0,0 +1,618 @@
+/* Test of locking in multithreaded situations.
+   Copyright (C) 2005, 2008-2023 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_ISOC_THREADS || USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS || USE_WINDOWS_THREADS
+
+#if USE_ISOC_THREADS
+# define TEST_ISOC_THREADS 1
+#endif
+#if USE_POSIX_THREADS
+# define TEST_POSIX_THREADS 1
+#endif
+#if USE_ISOC_AND_POSIX_THREADS
+# define TEST_ISOC_AND_POSIX_THREADS 1
+#endif
+#if USE_WINDOWS_THREADS
+# define TEST_WINDOWS_THREADS 1
+#endif
+
+/* 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_RWLOCK 1
+#define DO_TEST_RECURSIVE_LOCK 1
+#define DO_TEST_ONCE 1
+
+/* Whether to help the scheduler through explicit yield().
+   Uncomment this to see if the operating system has a fair scheduler.  */
+#define EXPLICIT_YIELD 1
+
+/* 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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if !ENABLE_LOCKING
+# undef USE_ISOC_THREADS
+# undef USE_POSIX_THREADS
+# undef USE_ISOC_AND_POSIX_THREADS
+# undef USE_WINDOWS_THREADS
+#endif
+#include "glthread/lock.h"
+
+#if !ENABLE_LOCKING
+# if TEST_ISOC_THREADS
+#  define USE_ISOC_THREADS 1
+# endif
+# if TEST_POSIX_THREADS
+#  define USE_POSIX_THREADS 1
+# endif
+# if TEST_ISOC_AND_POSIX_THREADS
+#  define USE_ISOC_AND_POSIX_THREADS 1
+# endif
+# if TEST_WINDOWS_THREADS
+#  define USE_WINDOWS_THREADS 1
+# endif
+#endif
+
+#include "glthread/thread.h"
+#include "glthread/yield.h"
+
+#if HAVE_DECL_ALARM
+# include <signal.h>
+# include <unistd.h>
+#endif
+
+#include "atomic-int-gnulib.h"
+
+#if ENABLE_DEBUGGING
+# define dbgprintf printf
+#else
+# define dbgprintf if (0) printf
+#endif
+
+#if EXPLICIT_YIELD
+# define yield() gl_thread_yield ()
+#else
+# define yield()
+#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.  */
+
+gl_lock_define_initialized(static, 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", gl_thread_self_pointer ());
+      gl_lock_lock (my_lock);
+      dbgprintf ("Mutator %p after  lock\n", gl_thread_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", gl_thread_self_pointer ());
+      gl_lock_unlock (my_lock);
+      dbgprintf ("Mutator %p after  unlock\n", gl_thread_self_pointer ());
+
+      dbgprintf ("Mutator %p before check lock\n", gl_thread_self_pointer ());
+      gl_lock_lock (my_lock);
+      check_accounts ();
+      gl_lock_unlock (my_lock);
+      dbgprintf ("Mutator %p after  check unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Mutator %p dying.\n", gl_thread_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", gl_thread_self_pointer ());
+      gl_lock_lock (my_lock);
+      check_accounts ();
+      gl_lock_unlock (my_lock);
+      dbgprintf ("Checker %p after  check unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Checker %p dying.\n", gl_thread_self_pointer ());
+  return NULL;
+}
+
+static void
+test_lock (void)
+{
+  int i;
+  gl_thread_t checkerthread;
+  gl_thread_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.  */
+  checkerthread = gl_thread_create (lock_checker_thread, NULL);
+  for (i = 0; i < THREAD_COUNT; i++)
+    threads[i] = gl_thread_create (lock_mutator_thread, NULL);
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    gl_thread_join (threads[i], NULL);
+  set_atomic_int_value (&lock_checker_done, 1);
+  gl_thread_join (checkerthread, NULL);
+  check_accounts ();
+}
+
+
+/* ----------------- Test read-write (non-recursive) locks ----------------- */
+
+/* Test read-write locks by having several bank accounts and several threads
+   which shuffle around money between the accounts and several other threads
+   that check that all the money is still there.  */
+
+gl_rwlock_define_initialized(static, my_rwlock)
+
+static void *
+rwlock_mutator_thread (void *arg)
+{
+  int repeat;
+
+  for (repeat = REPEAT_COUNT; repeat > 0; repeat--)
+    {
+      int i1, i2, value;
+
+      dbgprintf ("Mutator %p before wrlock\n", gl_thread_self_pointer ());
+      gl_rwlock_wrlock (my_rwlock);
+      dbgprintf ("Mutator %p after  wrlock\n", gl_thread_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", gl_thread_self_pointer ());
+      gl_rwlock_unlock (my_rwlock);
+      dbgprintf ("Mutator %p after  unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Mutator %p dying.\n", gl_thread_self_pointer ());
+  return NULL;
+}
+
+static struct atomic_int rwlock_checker_done;
+
+static void *
+rwlock_checker_thread (void *arg)
+{
+  while (get_atomic_int_value (&rwlock_checker_done) == 0)
+    {
+      dbgprintf ("Checker %p before check rdlock\n", gl_thread_self_pointer ());
+      gl_rwlock_rdlock (my_rwlock);
+      check_accounts ();
+      gl_rwlock_unlock (my_rwlock);
+      dbgprintf ("Checker %p after  check unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Checker %p dying.\n", gl_thread_self_pointer ());
+  return NULL;
+}
+
+static void
+test_rwlock (void)
+{
+  int i;
+  gl_thread_t checkerthreads[THREAD_COUNT];
+  gl_thread_t threads[THREAD_COUNT];
+
+  /* Initialization.  */
+  for (i = 0; i < ACCOUNT_COUNT; i++)
+    account[i] = 1000;
+  init_atomic_int (&rwlock_checker_done);
+  set_atomic_int_value (&rwlock_checker_done, 0);
+
+  /* Spawn the threads.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    checkerthreads[i] = gl_thread_create (rwlock_checker_thread, NULL);
+  for (i = 0; i < THREAD_COUNT; i++)
+    threads[i] = gl_thread_create (rwlock_mutator_thread, NULL);
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    gl_thread_join (threads[i], NULL);
+  set_atomic_int_value (&rwlock_checker_done, 1);
+  for (i = 0; i < THREAD_COUNT; i++)
+    gl_thread_join (checkerthreads[i], NULL);
+  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.  */
+
+gl_recursive_lock_define_initialized(static, my_reclock)
+
+static void
+recshuffle (void)
+{
+  int i1, i2, value;
+
+  dbgprintf ("Mutator %p before lock\n", gl_thread_self_pointer ());
+  gl_recursive_lock_lock (my_reclock);
+  dbgprintf ("Mutator %p after  lock\n", gl_thread_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", gl_thread_self_pointer ());
+  gl_recursive_lock_unlock (my_reclock);
+  dbgprintf ("Mutator %p after  unlock\n", gl_thread_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", gl_thread_self_pointer ());
+      gl_recursive_lock_lock (my_reclock);
+      check_accounts ();
+      gl_recursive_lock_unlock (my_reclock);
+      dbgprintf ("Mutator %p after  check unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Mutator %p dying.\n", gl_thread_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", gl_thread_self_pointer ());
+      gl_recursive_lock_lock (my_reclock);
+      check_accounts ();
+      gl_recursive_lock_unlock (my_reclock);
+      dbgprintf ("Checker %p after  check unlock\n", gl_thread_self_pointer ());
+
+      yield ();
+    }
+
+  dbgprintf ("Checker %p dying.\n", gl_thread_self_pointer ());
+  return NULL;
+}
+
+static void
+test_recursive_lock (void)
+{
+  int i;
+  gl_thread_t checkerthread;
+  gl_thread_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.  */
+  checkerthread = gl_thread_create (reclock_checker_thread, NULL);
+  for (i = 0; i < THREAD_COUNT; i++)
+    threads[i] = gl_thread_create (reclock_mutator_thread, NULL);
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    gl_thread_join (threads[i], NULL);
+  set_atomic_int_value (&reclock_checker_done, 1);
+  gl_thread_join (checkerthread, NULL);
+  check_accounts ();
+}
+
+
+/* ------------------------ Test once-only execution ------------------------ */
+
+/* Test once-only execution by having several threads attempt to grab a
+   once-only task simultaneously (triggered by releasing a read-write lock).  */
+
+gl_once_define(static, fresh_once)
+static int ready[THREAD_COUNT];
+static gl_lock_t ready_lock[THREAD_COUNT];
+#if ENABLE_LOCKING
+static gl_rwlock_t fire_signal[REPEAT_COUNT];
+#else
+static volatile int fire_signal_state;
+#endif
+static gl_once_t once_control;
+static int performed;
+gl_lock_define_initialized(static, performed_lock)
+
+static void
+once_execute (void)
+{
+  gl_lock_lock (performed_lock);
+  performed++;
+  gl_lock_unlock (performed_lock);
+}
+
+static void *
+once_contender_thread (void *arg)
+{
+  int id = (int) (intptr_t) arg;
+  int repeat;
+
+  for (repeat = 0; repeat <= REPEAT_COUNT; repeat++)
+    {
+      /* Tell the main thread that we're ready.  */
+      gl_lock_lock (ready_lock[id]);
+      ready[id] = 1;
+      gl_lock_unlock (ready_lock[id]);
+
+      if (repeat == REPEAT_COUNT)
+        break;
+
+      dbgprintf ("Contender %p waiting for signal for round %d\n",
+                 gl_thread_self_pointer (), repeat);
+#if ENABLE_LOCKING
+      /* Wait for the signal to go.  */
+      gl_rwlock_rdlock (fire_signal[repeat]);
+      /* And don't hinder the others (if the scheduler is unfair).  */
+      gl_rwlock_unlock (fire_signal[repeat]);
+#else
+      /* Wait for the signal to go.  */
+      while (fire_signal_state <= repeat)
+        yield ();
+#endif
+      dbgprintf ("Contender %p got the     signal for round %d\n",
+                 gl_thread_self_pointer (), repeat);
+
+      /* Contend for execution.  */
+      gl_once (once_control, once_execute);
+    }
+
+  return NULL;
+}
+
+static void
+test_once (void)
+{
+  int i, repeat;
+  gl_thread_t threads[THREAD_COUNT];
+
+  /* Initialize all variables.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    {
+      ready[i] = 0;
+      gl_lock_init (ready_lock[i]);
+    }
+#if ENABLE_LOCKING
+  for (i = 0; i < REPEAT_COUNT; i++)
+    gl_rwlock_init (fire_signal[i]);
+#else
+  fire_signal_state = 0;
+#endif
+
+#if ENABLE_LOCKING
+  /* Block all fire_signals.  */
+  for (i = REPEAT_COUNT-1; i >= 0; i--)
+    gl_rwlock_wrlock (fire_signal[i]);
+#endif
+
+  /* Spawn the threads.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    threads[i] =
+      gl_thread_create (once_contender_thread, (void *) (intptr_t) i);
+
+  for (repeat = 0; repeat <= REPEAT_COUNT; repeat++)
+    {
+      /* Wait until every thread is ready.  */
+      dbgprintf ("Main thread before synchronizing for round %d\n", repeat);
+      for (;;)
+        {
+          int ready_count = 0;
+          for (i = 0; i < THREAD_COUNT; i++)
+            {
+              gl_lock_lock (ready_lock[i]);
+              ready_count += ready[i];
+              gl_lock_unlock (ready_lock[i]);
+            }
+          if (ready_count == THREAD_COUNT)
+            break;
+          yield ();
+        }
+      dbgprintf ("Main thread after  synchronizing for round %d\n", repeat);
+
+      if (repeat > 0)
+        {
+          /* Check that exactly one thread executed the once_execute()
+             function.  */
+          if (performed != 1)
+            abort ();
+        }
+
+      if (repeat == REPEAT_COUNT)
+        break;
+
+      /* Preparation for the next round: Initialize once_control.  */
+      memcpy (&once_control, &fresh_once, sizeof (gl_once_t));
+
+      /* Preparation for the next round: Reset the performed counter.  */
+      performed = 0;
+
+      /* Preparation for the next round: Reset the ready flags.  */
+      for (i = 0; i < THREAD_COUNT; i++)
+        {
+          gl_lock_lock (ready_lock[i]);
+          ready[i] = 0;
+          gl_lock_unlock (ready_lock[i]);
+        }
+
+      /* Signal all threads simultaneously.  */
+      dbgprintf ("Main thread giving signal for round %d\n", repeat);
+#if ENABLE_LOCKING
+      gl_rwlock_unlock (fire_signal[repeat]);
+#else
+      fire_signal_state = repeat + 1;
+#endif
+    }
+
+  /* Wait for the threads to terminate.  */
+  for (i = 0; i < THREAD_COUNT; i++)
+    gl_thread_join (threads[i], NULL);
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+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
+
+#if DO_TEST_LOCK
+  printf ("Starting test_lock ..."); fflush (stdout);
+  test_lock ();
+  printf (" OK\n"); fflush (stdout);
+#endif
+#if DO_TEST_RWLOCK
+  printf ("Starting test_rwlock ..."); fflush (stdout);
+  test_rwlock ();
+  printf (" OK\n"); fflush (stdout);
+#endif
+#if DO_TEST_RECURSIVE_LOCK
+  printf ("Starting test_recursive_lock ..."); fflush (stdout);
+  test_recursive_lock ();
+  printf (" OK\n"); fflush (stdout);
+#endif
+#if DO_TEST_ONCE
+  printf ("Starting test_once ..."); fflush (stdout);
+  test_once ();
+  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