static dbus_bool_t have_monotonic_clock = 0;
typedef struct {
- pthread_mutex_t lock; /**< lock protecting count field */
- volatile int count; /**< count of how many times lock holder has recursively locked */
- volatile pthread_t holder; /**< holder of the lock if count >0,
- valid but arbitrary thread if count
- has ever been >0, uninitialized memory
- if count has never been >0 */
+ pthread_mutex_t lock; /**< the lock */
} DBusMutexPThread;
typedef struct {
} while (0)
#endif /* !DBUS_DISABLE_ASSERT */
-static DBusMutex*
-_dbus_pthread_mutex_new (void)
+static DBusMutex *
+_dbus_pthread_cmutex_new (void)
{
DBusMutexPThread *pmutex;
int result;
-
+
pmutex = dbus_new (DBusMutexPThread, 1);
if (pmutex == NULL)
return NULL;
PTHREAD_CHECK ("pthread_mutex_init", result);
}
- /* Only written */
- pmutex->count = 0;
+ return DBUS_MUTEX (pmutex);
+}
+
+static DBusMutex *
+_dbus_pthread_rmutex_new (void)
+{
+ DBusMutexPThread *pmutex;
+ pthread_mutexattr_t mutexattr;
+ int result;
+
+ pmutex = dbus_new (DBusMutexPThread, 1);
+ if (pmutex == NULL)
+ return NULL;
+
+ pthread_mutexattr_init (&mutexattr);
+ pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
+ result = pthread_mutex_init (&pmutex->lock, &mutexattr);
+ pthread_mutexattr_destroy (&mutexattr);
+
+ if (result == ENOMEM || result == EAGAIN)
+ {
+ dbus_free (pmutex);
+ return NULL;
+ }
+ else
+ {
+ PTHREAD_CHECK ("pthread_mutex_init", result);
+ }
- /* There's no portable way to have a "null" pthread afaik so we
- * can't set pmutex->holder to anything sensible. We only access it
- * once the lock is held (which means we've set it).
- */
-
return DBUS_MUTEX (pmutex);
}
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
- _dbus_assert (pmutex->count == 0);
-
PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&pmutex->lock));
-
dbus_free (pmutex);
}
-static void
+static dbus_bool_t
_dbus_pthread_mutex_lock (DBusMutex *mutex)
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
- pthread_t self = pthread_self ();
-
- /* If the count is > 0 then someone had the lock, maybe us. If it is
- * 0, then it might immediately change right after we read it,
- * but it will be changed by another thread; i.e. if we read 0,
- * we assume that this thread doesn't have the lock.
- *
- * Not 100% sure this is safe, but ... seems like it should be.
- */
- if (pmutex->count == 0)
- {
- /* We know we don't have the lock; someone may have the lock. */
-
- PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
-
- /* We now have the lock. Count must be 0 since it must be 0 when
- * the lock is released by another thread, and we just now got
- * the lock.
- */
- _dbus_assert (pmutex->count == 0);
-
- pmutex->holder = self;
- pmutex->count = 1;
- }
- else
- {
- /* We know someone had the lock, possibly us. Thus
- * pmutex->holder is not pointing to junk, though it may not be
- * the lock holder anymore if the lock holder is not us. If the
- * lock holder is us, then we definitely have the lock.
- */
-
- if (pthread_equal (pmutex->holder, self))
- {
- /* We already have the lock. */
- _dbus_assert (pmutex->count > 0);
- }
- else
- {
- /* Wait for the lock */
- PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
- pmutex->holder = self;
- _dbus_assert (pmutex->count == 0);
- }
-
- pmutex->count += 1;
- }
+
+ PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
+ return TRUE;
}
-static void
+static dbus_bool_t
_dbus_pthread_mutex_unlock (DBusMutex *mutex)
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
- _dbus_assert (pmutex->count > 0);
-
- pmutex->count -= 1;
-
- if (pmutex->count == 0)
- PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&pmutex->lock));
-
- /* We leave pmutex->holder set to ourselves, its content is undefined if count is 0 */
+ PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&pmutex->lock));
+ return TRUE;
}
static DBusCondVar *
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
- int old_count;
-
- _dbus_assert (pmutex->count > 0);
- _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
- old_count = pmutex->count;
- pmutex->count = 0; /* allow other threads to lock */
PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&pcond->cond, &pmutex->lock));
- _dbus_assert (pmutex->count == 0);
- pmutex->count = old_count;
- pmutex->holder = pthread_self(); /* other threads may have locked the mutex in the meantime */
}
static dbus_bool_t
struct timeval time_now;
struct timespec end_time;
int result;
- int old_count;
-
- _dbus_assert (pmutex->count > 0);
- _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
#ifdef HAVE_MONOTONIC_CLOCK
if (have_monotonic_clock)
end_time.tv_nsec -= 1000*1000*1000;
}
- old_count = pmutex->count;
- pmutex->count = 0;
result = pthread_cond_timedwait (&pcond->cond, &pmutex->lock, &end_time);
if (result != ETIMEDOUT)
PTHREAD_CHECK ("pthread_cond_timedwait", result);
}
- _dbus_assert (pmutex->count == 0);
- pmutex->count = old_count;
- pmutex->holder = pthread_self(); /* other threads may have locked the mutex in the meantime */
-
/* return true if we did not time out */
return result != ETIMEDOUT;
}
static const DBusThreadFunctions pthread_functions =
{
+ DBUS_THREAD_FUNCTIONS_MUTEX_NEW_MASK |
+ DBUS_THREAD_FUNCTIONS_MUTEX_FREE_MASK |
+ DBUS_THREAD_FUNCTIONS_MUTEX_LOCK_MASK |
+ DBUS_THREAD_FUNCTIONS_MUTEX_UNLOCK_MASK |
DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK |
DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK |
DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK|
DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK,
- NULL, NULL, NULL, NULL,
+ _dbus_pthread_cmutex_new,
+ _dbus_pthread_mutex_free,
+ _dbus_pthread_mutex_lock,
+ _dbus_pthread_mutex_unlock,
_dbus_pthread_condvar_new,
_dbus_pthread_condvar_free,
_dbus_pthread_condvar_wait,
_dbus_pthread_condvar_wait_timeout,
_dbus_pthread_condvar_wake_one,
_dbus_pthread_condvar_wake_all,
- _dbus_pthread_mutex_new,
+ _dbus_pthread_rmutex_new,
_dbus_pthread_mutex_free,
- _dbus_pthread_mutex_lock,
- _dbus_pthread_mutex_unlock
+ (void (*) (DBusMutex *)) _dbus_pthread_mutex_lock,
+ (void (*) (DBusMutex *)) _dbus_pthread_mutex_unlock
};
static void
projects / platform / upstream / dbus.git / commitdiff