/* Locking in multithreaded situations.
- Copyright (C) 2005-2008 Free Software Foundation, Inc.
+ Copyright (C) 2005-2014 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
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, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program; if not, see <http://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2005.
Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
#if USE_POSIX_THREADS
-/* Use the POSIX threads library. */
-
-# if PTHREAD_IN_USE_DETECTION_HARD
-
-/* The function to be executed by a dummy thread. */
-static void *
-dummy_thread_func (void *arg)
-{
- return arg;
-}
-
-int
-glthread_in_use (void)
-{
- static int tested;
- static int result; /* 1: linked with -lpthread, 0: only with libc */
-
- if (!tested)
- {
- pthread_t thread;
-
- if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
- /* Thread creation failed. */
- result = 0;
- else
- {
- /* Thread creation works. */
- void *retval;
- if (pthread_join (thread, &retval) != 0)
- abort ();
- result = 1;
- }
- tested = 1;
- }
- return result;
-}
-
-# endif
-
/* -------------------------- gl_lock_t datatype -------------------------- */
/* ------------------------- gl_rwlock_t datatype ------------------------- */
err = pthread_mutex_lock (&lock->guard);
if (err != 0)
- return err;
+ return err;
if (!lock->initialized)
- {
- err = glthread_rwlock_init_multithreaded (lock);
- if (err != 0)
- {
- pthread_mutex_unlock (&lock->guard);
- return err;
- }
- }
+ {
+ err = glthread_rwlock_init_multithreaded (lock);
+ if (err != 0)
+ {
+ pthread_mutex_unlock (&lock->guard);
+ return err;
+ }
+ }
err = pthread_mutex_unlock (&lock->guard);
if (err != 0)
- return err;
+ return err;
}
return pthread_rwlock_rdlock (&lock->rwlock);
}
err = pthread_mutex_lock (&lock->guard);
if (err != 0)
- return err;
+ return err;
if (!lock->initialized)
- {
- err = glthread_rwlock_init_multithreaded (lock);
- if (err != 0)
- {
- pthread_mutex_unlock (&lock->guard);
- return err;
- }
- }
+ {
+ err = glthread_rwlock_init_multithreaded (lock);
+ if (err != 0)
+ {
+ pthread_mutex_unlock (&lock->guard);
+ return err;
+ }
+ }
err = pthread_mutex_unlock (&lock->guard);
if (err != 0)
- return err;
+ return err;
}
return pthread_rwlock_wrlock (&lock->rwlock);
}
while (!(lock->runcount + 1 > 0 && lock->waiting_writers_count == 0))
{
/* This thread has to wait for a while. Enqueue it among the
- waiting_readers. */
+ waiting_readers. */
err = pthread_cond_wait (&lock->waiting_readers, &lock->lock);
if (err != 0)
- {
- pthread_mutex_unlock (&lock->lock);
- return err;
- }
+ {
+ pthread_mutex_unlock (&lock->lock);
+ return err;
+ }
}
lock->runcount++;
return pthread_mutex_unlock (&lock->lock);
while (!(lock->runcount == 0))
{
/* This thread has to wait for a while. Enqueue it among the
- waiting_writers. */
+ 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--;
+ pthread_mutex_unlock (&lock->lock);
+ return err;
+ }
lock->waiting_writers_count--;
}
lock->runcount--; /* runcount becomes -1 */
{
/* Drop a writer lock. */
if (!(lock->runcount == -1))
- {
- pthread_mutex_unlock (&lock->lock);
- return EINVAL;
- }
+ {
+ 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;
- }
+ {
+ 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". */
+ 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;
- }
- }
+ {
+ /* 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;
- }
- }
+ {
+ /* 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);
}
err = pthread_mutex_lock (&lock->guard);
if (err != 0)
- return err;
+ return err;
if (!lock->initialized)
- {
- err = glthread_recursive_lock_init_multithreaded (lock);
- if (err != 0)
- {
- pthread_mutex_unlock (&lock->guard);
- return err;
- }
- }
+ {
+ err = glthread_recursive_lock_init_multithreaded (lock);
+ if (err != 0)
+ {
+ pthread_mutex_unlock (&lock->guard);
+ return err;
+ }
+ }
err = pthread_mutex_unlock (&lock->guard);
if (err != 0)
- return err;
+ return err;
}
return pthread_mutex_lock (&lock->recmutex);
}
err = pthread_mutex_lock (&lock->mutex);
if (err != 0)
- return err;
+ return err;
lock->owner = self;
}
if (++(lock->depth) == 0) /* wraparound? */
{
if (lock->owner != (pthread_t) 0)
return EBUSY;
- return (pthread_mutex_destroy (&lock->mutex);
+ return pthread_mutex_destroy (&lock->mutex);
}
# endif
err = mutex_lock (&lock->mutex);
if (err != 0)
- return err;
+ return err;
lock->owner = self;
}
if (++(lock->depth) == 0) /* wraparound? */
int err;
/* Use the mutex to guarantee that if another thread is already calling
- the initfunction, this thread waits until it's finished. */
+ the initfunction, this thread waits until it's finished. */
err = mutex_lock (&once_control->mutex);
if (err != 0)
- return err;
+ return err;
if (!once_control->inited)
- {
- once_control->inited = 1;
- initfunction ();
- }
+ {
+ once_control->inited = 1;
+ initfunction ();
+ }
return mutex_unlock (&once_control->mutex);
}
else
/* ========================================================================= */
-#if USE_WIN32_THREADS
+#if USE_WINDOWS_THREADS
/* -------------------------- gl_lock_t datatype -------------------------- */
}
int
-glthread_lock_lock (gl_lock_t *lock)
+glthread_lock_lock_func (gl_lock_t *lock)
{
if (!lock->guard.done)
{
if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_lock_init (lock);
+ /* This thread is the first one to need this lock. Initialize it. */
+ glthread_lock_init (lock);
else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
}
EnterCriticalSection (&lock->lock);
return 0;
}
int
-glthread_lock_unlock (gl_lock_t *lock)
+glthread_lock_unlock_func (gl_lock_t *lock)
{
if (!lock->guard.done)
return EINVAL;
}
int
-glthread_lock_destroy (gl_lock_t *lock)
+glthread_lock_destroy_func (gl_lock_t *lock)
{
if (!lock->guard.done)
return EINVAL;
/* ------------------------- gl_rwlock_t datatype ------------------------- */
-static inline void
+/* In this file, the waitqueues are implemented as circular arrays. */
+#define gl_waitqueue_t gl_carray_waitqueue_t
+
+static void
gl_waitqueue_init (gl_waitqueue_t *wq)
{
wq->array = NULL;
{
unsigned int new_alloc = 2 * wq->alloc + 1;
HANDLE *new_array =
- (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
+ (HANDLE *) realloc (wq->array, new_alloc * sizeof (HANDLE));
if (new_array == NULL)
- /* No more memory. */
- return INVALID_HANDLE_VALUE;
+ /* No more memory. */
+ return INVALID_HANDLE_VALUE;
/* Now is a good opportunity to rotate the array so that its contents
- starts at offset 0. */
+ starts at offset 0. */
if (wq->offset > 0)
- {
- unsigned int old_count = wq->count;
- unsigned int old_alloc = wq->alloc;
- unsigned int old_offset = wq->offset;
- unsigned int i;
- if (old_offset + old_count > old_alloc)
- {
- unsigned int limit = old_offset + old_count - old_alloc;
- for (i = 0; i < limit; i++)
- new_array[old_alloc + i] = new_array[i];
- }
- for (i = 0; i < old_count; i++)
- new_array[i] = new_array[old_offset + i];
- wq->offset = 0;
- }
+ {
+ unsigned int old_count = wq->count;
+ unsigned int old_alloc = wq->alloc;
+ unsigned int old_offset = wq->offset;
+ unsigned int i;
+ if (old_offset + old_count > old_alloc)
+ {
+ unsigned int limit = old_offset + old_count - old_alloc;
+ for (i = 0; i < limit; i++)
+ new_array[old_alloc + i] = new_array[i];
+ }
+ for (i = 0; i < old_count; i++)
+ new_array[i] = new_array[old_offset + i];
+ wq->offset = 0;
+ }
wq->array = new_array;
wq->alloc = new_alloc;
}
+ /* Whether the created event is a manual-reset one or an auto-reset one,
+ does not matter, since we will wait on it only once. */
event = CreateEvent (NULL, TRUE, FALSE, NULL);
if (event == INVALID_HANDLE_VALUE)
/* No way to allocate an event. */
}
/* Notifies the first thread from a wait queue and dequeues it. */
-static inline void
+static void
gl_waitqueue_notify_first (gl_waitqueue_t *wq)
{
SetEvent (wq->array[wq->offset + 0]);
}
/* Notifies all threads from a wait queue and dequeues them all. */
-static inline void
+static void
gl_waitqueue_notify_all (gl_waitqueue_t *wq)
{
unsigned int i;
{
unsigned int index = wq->offset + i;
if (index >= wq->alloc)
- index -= wq->alloc;
+ index -= wq->alloc;
SetEvent (wq->array[index]);
}
wq->count = 0;
}
int
-glthread_rwlock_rdlock (gl_rwlock_t *lock)
+glthread_rwlock_rdlock_func (gl_rwlock_t *lock)
{
if (!lock->guard.done)
{
if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_rwlock_init (lock);
+ /* This thread is the first one to need this lock. Initialize it. */
+ glthread_rwlock_init (lock);
else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
}
EnterCriticalSection (&lock->lock);
/* Test whether only readers are currently running, and whether the runcount
if (!(lock->runcount + 1 > 0))
{
/* This thread has to wait for a while. Enqueue it among the
- waiting_readers. */
+ waiting_readers. */
HANDLE event = gl_waitqueue_add (&lock->waiting_readers);
if (event != INVALID_HANDLE_VALUE)
- {
- DWORD result;
- LeaveCriticalSection (&lock->lock);
- /* Wait until another thread signals this event. */
- result = WaitForSingleObject (event, INFINITE);
- if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
- abort ();
- CloseHandle (event);
- /* The thread which signalled the event already did the bookkeeping:
- removed us from the waiting_readers, incremented lock->runcount. */
- if (!(lock->runcount > 0))
- abort ();
- return 0;
- }
+ {
+ DWORD result;
+ LeaveCriticalSection (&lock->lock);
+ /* Wait until another thread signals this event. */
+ result = WaitForSingleObject (event, INFINITE);
+ if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+ abort ();
+ CloseHandle (event);
+ /* The thread which signalled the event already did the bookkeeping:
+ removed us from the waiting_readers, incremented lock->runcount. */
+ if (!(lock->runcount > 0))
+ abort ();
+ return 0;
+ }
else
- {
- /* Allocation failure. Weird. */
- do
- {
- LeaveCriticalSection (&lock->lock);
- Sleep (1);
- EnterCriticalSection (&lock->lock);
- }
- while (!(lock->runcount + 1 > 0));
- }
+ {
+ /* Allocation failure. Weird. */
+ do
+ {
+ LeaveCriticalSection (&lock->lock);
+ Sleep (1);
+ EnterCriticalSection (&lock->lock);
+ }
+ while (!(lock->runcount + 1 > 0));
+ }
}
lock->runcount++;
LeaveCriticalSection (&lock->lock);
}
int
-glthread_rwlock_wrlock (gl_rwlock_t *lock)
+glthread_rwlock_wrlock_func (gl_rwlock_t *lock)
{
if (!lock->guard.done)
{
if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_rwlock_init (lock);
+ /* This thread is the first one to need this lock. Initialize it. */
+ glthread_rwlock_init (lock);
else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
}
EnterCriticalSection (&lock->lock);
/* Test whether no readers or writers are currently running. */
if (!(lock->runcount == 0))
{
/* This thread has to wait for a while. Enqueue it among the
- waiting_writers. */
+ waiting_writers. */
HANDLE event = gl_waitqueue_add (&lock->waiting_writers);
if (event != INVALID_HANDLE_VALUE)
- {
- DWORD result;
- LeaveCriticalSection (&lock->lock);
- /* Wait until another thread signals this event. */
- result = WaitForSingleObject (event, INFINITE);
- if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
- abort ();
- CloseHandle (event);
- /* The thread which signalled the event already did the bookkeeping:
- removed us from the waiting_writers, set lock->runcount = -1. */
- if (!(lock->runcount == -1))
- abort ();
- return 0;
- }
+ {
+ DWORD result;
+ LeaveCriticalSection (&lock->lock);
+ /* Wait until another thread signals this event. */
+ result = WaitForSingleObject (event, INFINITE);
+ if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
+ abort ();
+ CloseHandle (event);
+ /* The thread which signalled the event already did the bookkeeping:
+ removed us from the waiting_writers, set lock->runcount = -1. */
+ if (!(lock->runcount == -1))
+ abort ();
+ return 0;
+ }
else
- {
- /* Allocation failure. Weird. */
- do
- {
- LeaveCriticalSection (&lock->lock);
- Sleep (1);
- EnterCriticalSection (&lock->lock);
- }
- while (!(lock->runcount == 0));
- }
+ {
+ /* Allocation failure. Weird. */
+ do
+ {
+ LeaveCriticalSection (&lock->lock);
+ Sleep (1);
+ EnterCriticalSection (&lock->lock);
+ }
+ while (!(lock->runcount == 0));
+ }
}
lock->runcount--; /* runcount becomes -1 */
LeaveCriticalSection (&lock->lock);
}
int
-glthread_rwlock_unlock (gl_rwlock_t *lock)
+glthread_rwlock_unlock_func (gl_rwlock_t *lock)
{
if (!lock->guard.done)
return EINVAL;
{
/* Drop a writer lock. */
if (!(lock->runcount == -1))
- abort ();
+ abort ();
lock->runcount = 0;
}
else
{
/* Drop a reader lock. */
if (!(lock->runcount > 0))
- {
- LeaveCriticalSection (&lock->lock);
- return EPERM;
- }
+ {
+ LeaveCriticalSection (&lock->lock);
+ return EPERM;
+ }
lock->runcount--;
}
if (lock->runcount == 0)
{
/* POSIX recommends that "write locks shall take precedence over read
- locks", to avoid "writer starvation". */
+ locks", to avoid "writer starvation". */
if (lock->waiting_writers.count > 0)
- {
- /* Wake up one of the waiting writers. */
- lock->runcount--;
- gl_waitqueue_notify_first (&lock->waiting_writers);
- }
+ {
+ /* Wake up one of the waiting writers. */
+ lock->runcount--;
+ gl_waitqueue_notify_first (&lock->waiting_writers);
+ }
else
- {
- /* Wake up all waiting readers. */
- lock->runcount += lock->waiting_readers.count;
- gl_waitqueue_notify_all (&lock->waiting_readers);
- }
+ {
+ /* Wake up all waiting readers. */
+ lock->runcount += lock->waiting_readers.count;
+ gl_waitqueue_notify_all (&lock->waiting_readers);
+ }
}
LeaveCriticalSection (&lock->lock);
return 0;
}
int
-glthread_rwlock_destroy (gl_rwlock_t *lock)
+glthread_rwlock_destroy_func (gl_rwlock_t *lock)
{
if (!lock->guard.done)
return EINVAL;
}
int
-glthread_recursive_lock_lock (gl_recursive_lock_t *lock)
+glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock)
{
if (!lock->guard.done)
{
if (InterlockedIncrement (&lock->guard.started) == 0)
- /* This thread is the first one to need this lock. Initialize it. */
- glthread_recursive_lock_init (lock);
+ /* This thread is the first one to need this lock. Initialize it. */
+ glthread_recursive_lock_init (lock);
else
- /* Yield the CPU while waiting for another thread to finish
- initializing this lock. */
- while (!lock->guard.done)
- Sleep (0);
+ /* Yield the CPU while waiting for another thread to finish
+ initializing this lock. */
+ while (!lock->guard.done)
+ Sleep (0);
}
{
DWORD self = GetCurrentThreadId ();
if (lock->owner != self)
{
- EnterCriticalSection (&lock->lock);
- lock->owner = self;
+ EnterCriticalSection (&lock->lock);
+ lock->owner = self;
}
if (++(lock->depth) == 0) /* wraparound? */
{
- lock->depth--;
- return EAGAIN;
+ lock->depth--;
+ return EAGAIN;
}
}
return 0;
}
int
-glthread_recursive_lock_unlock (gl_recursive_lock_t *lock)
+glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock)
{
if (lock->owner != GetCurrentThreadId ())
return EPERM;
}
int
-glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
+glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock)
{
if (lock->owner != 0)
return EBUSY;
if (once_control->inited <= 0)
{
if (InterlockedIncrement (&once_control->started) == 0)
- {
- /* This thread is the first one to come to this once_control. */
- InitializeCriticalSection (&once_control->lock);
- EnterCriticalSection (&once_control->lock);
- once_control->inited = 0;
- initfunction ();
- once_control->inited = 1;
- LeaveCriticalSection (&once_control->lock);
- }
+ {
+ /* This thread is the first one to come to this once_control. */
+ InitializeCriticalSection (&once_control->lock);
+ EnterCriticalSection (&once_control->lock);
+ once_control->inited = 0;
+ initfunction ();
+ once_control->inited = 1;
+ LeaveCriticalSection (&once_control->lock);
+ }
else
- {
- /* Undo last operation. */
- InterlockedDecrement (&once_control->started);
- /* Some other thread has already started the initialization.
- Yield the CPU while waiting for the other thread to finish
- initializing and taking the lock. */
- while (once_control->inited < 0)
- Sleep (0);
- if (once_control->inited <= 0)
- {
- /* Take the lock. This blocks until the other thread has
- finished calling the initfunction. */
- EnterCriticalSection (&once_control->lock);
- LeaveCriticalSection (&once_control->lock);
- if (!(once_control->inited > 0))
- abort ();
- }
- }
+ {
+ /* Undo last operation. */
+ InterlockedDecrement (&once_control->started);
+ /* Some other thread has already started the initialization.
+ Yield the CPU while waiting for the other thread to finish
+ initializing and taking the lock. */
+ while (once_control->inited < 0)
+ Sleep (0);
+ if (once_control->inited <= 0)
+ {
+ /* Take the lock. This blocks until the other thread has
+ finished calling the initfunction. */
+ EnterCriticalSection (&once_control->lock);
+ LeaveCriticalSection (&once_control->lock);
+ if (!(once_control->inited > 0))
+ abort ();
+ }
+ }
}
}
projects / gnulib.git / blobdiff