New upstream version 1.3upstream/1.3upstream

1 files changed, 624 insertions, 0 deletions

diff --git a/tests/pthread-rwlock.c b/tests/pthread-rwlock.c
new file mode 100644
index 00000000..46681538
--- /dev/null
+++ b/tests/pthread-rwlock.c
@@ -0,0 +1,624 @@
+/* POSIX read-write locks.
+   Copyright (C) 2019-2024 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2019.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <pthread.h>
+
+#if (defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS
+# include "windows-timedrwlock.h"
+#else
+# include <errno.h>
+# include <limits.h>
+# include <sys/time.h>
+# include <time.h>
+#endif
+
+#ifndef MIN
+# define MIN(a, b) ((a) < (b) ? (a) : (b))
+#endif
+
+#if ((defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS) || !HAVE_PTHREAD_H
+
+int
+pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
+{
+  *attr = 0;
+  return 0;
+}
+
+int
+pthread_rwlockattr_destroy (_GL_UNUSED pthread_rwlockattr_t *attr)
+{
+  return 0;
+}
+
+#elif PTHREAD_RWLOCK_BAD_WAITQUEUE
+
+/* Override pthread_rwlockattr_init, to use the kind PREFER_WRITER_NONRECURSIVE
+   (or possibly PREFER_WRITER) instead of the kind DEFAULT.  */
+int
+pthread_rwlockattr_init (pthread_rwlockattr_t *attr)
+# undef pthread_rwlockattr_init
+{
+  int err;
+
+  err = pthread_rwlockattr_init (attr);
+  if (err != 0)
+    return err;
+  err = pthread_rwlockattr_setkind_np (attr,
+                                       PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP);
+  if (err != 0)
+    {
+      pthread_rwlockattr_destroy (attr);
+      return err;
+    }
+  return 0;
+}
+
+#endif
+
+#if (defined _WIN32 && ! defined __CYGWIN__) && USE_WINDOWS_THREADS
+/* Use Windows threads.  */
+
+int
+pthread_rwlock_init (pthread_rwlock_t *lock,
+                     _GL_UNUSED const pthread_rwlockattr_t *attr)
+{
+  glwthread_timedrwlock_init (lock);
+  return 0;
+}
+
+int
+pthread_rwlock_rdlock (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_rdlock (lock);
+}
+
+int
+pthread_rwlock_wrlock (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_wrlock (lock);
+}
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_tryrdlock (lock);
+}
+
+int
+pthread_rwlock_trywrlock (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_trywrlock (lock);
+}
+
+int
+pthread_rwlock_timedrdlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  return glwthread_timedrwlock_timedrdlock (lock, abstime);
+}
+
+int
+pthread_rwlock_timedwrlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  return glwthread_timedrwlock_timedwrlock (lock, abstime);
+}
+
+int
+pthread_rwlock_unlock (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_unlock (lock);
+}
+
+int
+pthread_rwlock_destroy (pthread_rwlock_t *lock)
+{
+  return glwthread_timedrwlock_destroy (lock);
+}
+
+#elif HAVE_PTHREAD_H
+/* Provide workarounds for POSIX threads.  */
+
+# if PTHREAD_RWLOCK_UNIMPLEMENTED
+
+int
+pthread_rwlock_init (pthread_rwlock_t *lock,
+                     _GL_UNUSED const pthread_rwlockattr_t *attr)
+{
+  int err;
+
+  err = pthread_mutex_init (&lock->lock, NULL);
+  if (err != 0)
+    return err;
+  err = pthread_cond_init (&lock->waiting_readers, NULL);
+  if (err != 0)
+    return err;
+  err = pthread_cond_init (&lock->waiting_writers, NULL);
+  if (err != 0)
+    return err;
+  lock->waiting_writers_count = 0;
+  lock->runcount = 0;
+  return 0;
+}
+
+int
+pthread_rwlock_rdlock (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether only readers are currently running, and whether the runcount
+     field will not overflow, and whether no writer is waiting.  The latter
+     condition is because POSIX recommends that "write locks shall take
+     precedence over read locks", to avoid "writer starvation".  */
+  while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+         waiting_readers.  */
+      err = pthread_cond_wait (&lock->waiting_readers, &lock->lock);
+      if (err != 0)
+        {
+          pthread_mutex_unlock (&lock->lock);
+          return err;
+        }
+    }
+  lock->runcount++;
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_wrlock (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether no readers or writers are currently running.  */
+  while (!(lock->runcount == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+         waiting_writers.  */
+      lock->waiting_writers_count++;
+      err = pthread_cond_wait (&lock->waiting_writers, &lock->lock);
+      if (err != 0)
+        {
+          lock->waiting_writers_count--;
+          pthread_mutex_unlock (&lock->lock);
+          return err;
+        }
+      lock->waiting_writers_count--;
+    }
+  lock->runcount--; /* runcount becomes -1 */
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether only readers are currently running, and whether the runcount
+     field will not overflow, and whether no writer is waiting.  The latter
+     condition is because POSIX recommends that "write locks shall take
+     precedence over read locks", to avoid "writer starvation".  */
+  if (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
+    {
+      /* This thread would have to wait for a while.  Return instead.  */
+      pthread_mutex_unlock (&lock->lock);
+      return EBUSY;
+    }
+  lock->runcount++;
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_trywrlock (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether no readers or writers are currently running.  */
+  if (!(lock->runcount == 0))
+    {
+      /* This thread would have to wait for a while.  Return instead.  */
+      pthread_mutex_unlock (&lock->lock);
+      return EBUSY;
+    }
+  lock->runcount--; /* runcount becomes -1 */
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_timedrdlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether only readers are currently running, and whether the runcount
+     field will not overflow, and whether no writer is waiting.  The latter
+     condition is because POSIX recommends that "write locks shall take
+     precedence over read locks", to avoid "writer starvation".  */
+  while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+         waiting_readers.  */
+      err = pthread_cond_timedwait (&lock->waiting_readers, &lock->lock,
+                                    abstime);
+      if (err != 0)
+        {
+          pthread_mutex_unlock (&lock->lock);
+          return err;
+        }
+    }
+  lock->runcount++;
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_timedwrlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  /* Test whether no readers or writers are currently running.  */
+  while (!(lock->runcount == 0))
+    {
+      /* This thread has to wait for a while.  Enqueue it among the
+         waiting_writers.  */
+      lock->waiting_writers_count++;
+      err = pthread_cond_timedwait (&lock->waiting_writers, &lock->lock,
+                                    abstime);
+      if (err != 0)
+        {
+          lock->waiting_writers_count--;
+          pthread_mutex_unlock (&lock->lock);
+          return err;
+        }
+      lock->waiting_writers_count--;
+    }
+  lock->runcount--; /* runcount becomes -1 */
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_unlock (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_lock (&lock->lock);
+  if (err != 0)
+    return err;
+  if (lock->runcount < 0)
+    {
+      /* Drop a writer lock.  */
+      if (!(lock->runcount == -1))
+        {
+          pthread_mutex_unlock (&lock->lock);
+          return EINVAL;
+        }
+      lock->runcount = 0;
+    }
+  else
+    {
+      /* Drop a reader lock.  */
+      if (!(lock->runcount > 0))
+        {
+          pthread_mutex_unlock (&lock->lock);
+          return EINVAL;
+        }
+      lock->runcount--;
+    }
+  if (lock->runcount == 0)
+    {
+      /* POSIX recommends that "write locks shall take precedence over read
+         locks", to avoid "writer starvation".  */
+      if (lock->waiting_writers_count > 0)
+        {
+          /* Wake up one of the waiting writers.  */
+          err = pthread_cond_signal (&lock->waiting_writers);
+          if (err != 0)
+            {
+              pthread_mutex_unlock (&lock->lock);
+              return err;
+            }
+        }
+      else
+        {
+          /* Wake up all waiting readers.  */
+          err = pthread_cond_broadcast (&lock->waiting_readers);
+          if (err != 0)
+            {
+              pthread_mutex_unlock (&lock->lock);
+              return err;
+            }
+        }
+    }
+  return pthread_mutex_unlock (&lock->lock);
+}
+
+int
+pthread_rwlock_destroy (pthread_rwlock_t *lock)
+{
+  int err;
+
+  err = pthread_mutex_destroy (&lock->lock);
+  if (err != 0)
+    return err;
+  err = pthread_cond_destroy (&lock->waiting_readers);
+  if (err != 0)
+    return err;
+  err = pthread_cond_destroy (&lock->waiting_writers);
+  if (err != 0)
+    return err;
+  return 0;
+}
+
+# else
+
+#  if PTHREAD_RWLOCK_BAD_WAITQUEUE
+
+/* Override pthread_rwlock_init, to use the kind PREFER_WRITER_NONRECURSIVE
+   (or possibly PREFER_WRITER) instead of the default, when no
+   pthread_rwlockattr_t object is specified.  */
+int
+pthread_rwlock_init (pthread_rwlock_t *lock, const pthread_rwlockattr_t *attr)
+#   undef pthread_rwlock_init
+{
+  int err;
+
+  if (attr != NULL)
+    err = pthread_rwlock_init (lock, attr);
+  else
+    {
+      pthread_rwlockattr_t replacement_attr;
+
+      err = pthread_rwlockattr_init (&replacement_attr);
+      if (err != 0)
+        return err;
+      err = pthread_rwlockattr_setkind_np (&replacement_attr,
+                                           PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP);
+      if (err != 0)
+        {
+          pthread_rwlockattr_destroy (&replacement_attr);
+          return err;
+        }
+      err = pthread_rwlock_init (lock, &replacement_attr);
+      pthread_rwlockattr_destroy (&replacement_attr);
+    }
+  return err;
+}
+
+#  endif
+
+#  if PTHREAD_RWLOCK_LACKS_TIMEOUT
+
+int
+pthread_rwlock_timedrdlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  /* Poll the lock's state in regular intervals.  Ugh.  */
+  for (;;)
+    {
+      int err;
+      struct timeval currtime;
+      unsigned long remaining;
+
+      err = pthread_rwlock_tryrdlock (lock);
+      if (err != EBUSY)
+        return err;
+
+      gettimeofday (&currtime, NULL);
+
+      if (currtime.tv_sec > abstime->tv_sec)
+        remaining = 0;
+      else
+        {
+          unsigned long seconds = abstime->tv_sec - currtime.tv_sec;
+          remaining = seconds * 1000000000;
+          if (remaining / 1000000000 != seconds) /* overflow? */
+            remaining = ULONG_MAX;
+          else
+            {
+              long nanoseconds =
+                abstime->tv_nsec - currtime.tv_usec * 1000;
+              if (nanoseconds >= 0)
+                {
+                  remaining += nanoseconds;
+                  if (remaining < nanoseconds) /* overflow? */
+                    remaining = ULONG_MAX;
+                }
+              else
+                {
+                  if (remaining >= - nanoseconds)
+                    remaining -= (- nanoseconds);
+                  else
+                    remaining = 0;
+                }
+            }
+        }
+      if (remaining == 0)
+        return ETIMEDOUT;
+
+      /* Sleep 1 ms.  */
+      struct timespec duration =
+        {
+          .tv_sec = 0,
+          .tv_nsec = MIN (1000000, remaining)
+        };
+      nanosleep (&duration, NULL);
+    }
+}
+
+int
+pthread_rwlock_timedwrlock (pthread_rwlock_t *lock,
+                            const struct timespec *abstime)
+{
+  /* Poll the lock's state in regular intervals.  Ugh.  */
+  for (;;)
+    {
+      int err;
+      struct timeval currtime;
+      unsigned long remaining;
+
+      err = pthread_rwlock_trywrlock (lock);
+      if (err != EBUSY)
+        return err;
+
+      gettimeofday (&currtime, NULL);
+
+      if (currtime.tv_sec > abstime->tv_sec)
+        remaining = 0;
+      else
+        {
+          unsigned long seconds = abstime->tv_sec - currtime.tv_sec;
+          remaining = seconds * 1000000000;
+          if (remaining / 1000000000 != seconds) /* overflow? */
+            remaining = ULONG_MAX;
+          else
+            {
+              long nanoseconds =
+                abstime->tv_nsec - currtime.tv_usec * 1000;
+              if (nanoseconds >= 0)
+                {
+                  remaining += nanoseconds;
+                  if (remaining < nanoseconds) /* overflow? */
+                    remaining = ULONG_MAX;
+                }
+              else
+                {
+                  if (remaining >= - nanoseconds)
+                    remaining -= (- nanoseconds);
+                  else
+                    remaining = 0;
+                }
+            }
+        }
+      if (remaining == 0)
+        return ETIMEDOUT;
+
+      /* Sleep 1 ms.  */
+      struct timespec duration =
+        {
+          .tv_sec = 0,
+          .tv_nsec = MIN (1000000, remaining)
+        };
+      nanosleep (&duration, NULL);
+    }
+}
+
+#  endif
+
+# endif
+
+#else
+/* Provide a dummy implementation for single-threaded applications.  */
+
+/* The pthread_rwlock_t is an 'int', representing the number of readers running,
+   or -1 when a writer runs.  */
+
+int
+pthread_rwlock_init (pthread_rwlock_t *lock,
+                     _GL_UNUSED const pthread_rwlockattr_t *attr)
+{
+  *lock = 0;
+  return 0;
+}
+
+int
+pthread_rwlock_rdlock (pthread_rwlock_t *lock)
+{
+  if (*lock < 0)
+    return EDEADLK;
+  (*lock)++;
+  return 0;
+}
+
+int
+pthread_rwlock_wrlock (pthread_rwlock_t *lock)
+{
+  if (*lock != 0)
+    return EDEADLK;
+  *lock = -1;
+  return 0;
+}
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t *lock)
+{
+  return pthread_rwlock_rdlock (lock);
+}
+
+int
+pthread_rwlock_trywrlock (pthread_rwlock_t *lock)
+{
+  return pthread_rwlock_wrlock (lock);
+}
+
+int
+pthread_rwlock_timedrdlock (pthread_rwlock_t *lock,
+                            _GL_UNUSED const struct timespec *abstime)
+{
+  return pthread_rwlock_rdlock (lock);
+}
+
+int
+pthread_rwlock_timedwrlock (pthread_rwlock_t *lock,
+                            _GL_UNUSED const struct timespec *abstime)
+{
+  return pthread_rwlock_wrlock (lock);
+}
+
+int
+pthread_rwlock_unlock (pthread_rwlock_t *lock)
+{
+  if (*lock == 0)
+    return EPERM;
+  if (*lock < 0)
+    *lock = 0;
+  else /* *lock > 0 */
+    (*lock)--;
+  return 0;
+}
+
+int
+pthread_rwlock_destroy (pthread_rwlock_t *lock)
+{
+  if (*lock)
+    return EBUSY;
+  return 0;
+}
+
+#endif