Commit fbfec98d authored by Havoc Pennington's avatar Havoc Pennington

2006-10-26 Havoc Pennington <hp@redhat.com>

	* dbus/dbus-sysdeps-pthread.c (_dbus_pthread_mutex_lock): change
	to be recursive
	(_dbus_pthread_mutex_unlock): make it recursive
	(_dbus_pthread_condvar_wait): save/restore the recursion count
	(_dbus_pthread_condvar_wait_timeout): save/restore the recursion count
parent bdbbf46c
2006-10-26 Havoc Pennington <hp@redhat.com>
* dbus/dbus-sysdeps-pthread.c (_dbus_pthread_mutex_lock): change
to be recursive
(_dbus_pthread_mutex_unlock): make it recursive
(_dbus_pthread_condvar_wait): save/restore the recursion count
(_dbus_pthread_condvar_wait_timeout): save/restore the recursion count
2006-10-26 Havoc Pennington <hp@redhat.com>
* doc/dbus-specification.xml: clarify the UUID text slightly
......
......@@ -31,6 +31,8 @@
typedef struct {
pthread_mutex_t lock;
int count;
pthread_t holder;
} DBusMutexPThread;
typedef struct {
......@@ -74,6 +76,14 @@ _dbus_pthread_mutex_new (void)
PTHREAD_CHECK ("pthread_mutex_init", result);
}
/* Only written */
pmutex->count = 0;
/* 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);
}
......@@ -81,30 +91,77 @@ static void
_dbus_pthread_mutex_free (DBusMutex *mutex)
{
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 dbus_bool_t
static void
_dbus_pthread_mutex_lock (DBusMutex *mutex)
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
return TRUE;
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 was before when we
* did not have the lock, and we have not changed it in this thread.
*/
_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. */
}
else
{
/* Wait for the lock */
PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
_dbus_assert (pmutex->count == 0);
}
pmutex->count += 1;
}
}
static dbus_bool_t
static void
_dbus_pthread_mutex_unlock (DBusMutex *mutex)
{
DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&pmutex->lock));
_dbus_assert (pmutex->count > 0);
pmutex->count -= 1;
return TRUE;
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 */
}
static DBusCondVar *
......@@ -148,8 +205,16 @@ _dbus_pthread_condvar_wait (DBusCondVar *cond,
{
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;
PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&pcond->cond, &pmutex->lock));
_dbus_assert (pmutex->count == 0);
pmutex->count = old_count;
}
static dbus_bool_t
......@@ -162,6 +227,10 @@ _dbus_pthread_condvar_wait_timeout (DBusCondVar *cond,
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 ()));
gettimeofday (&time_now, NULL);
......@@ -173,12 +242,17 @@ _dbus_pthread_condvar_wait_timeout (DBusCondVar *cond,
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;
/* return true if we did not time out */
return result != ETIMEDOUT;
......@@ -202,26 +276,27 @@ _dbus_pthread_condvar_wake_all (DBusCondVar *cond)
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_RECURSIVE_MUTEX_UNLOCK_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK |
DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK|
DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK,
_dbus_pthread_mutex_new,
_dbus_pthread_mutex_free,
_dbus_pthread_mutex_lock,
_dbus_pthread_mutex_unlock,
NULL, NULL, NULL, NULL,
_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_condvar_wake_all,
_dbus_pthread_mutex_new,
_dbus_pthread_mutex_free,
_dbus_pthread_mutex_lock,
_dbus_pthread_mutex_unlock
};
dbus_bool_t
......
Important for 1.0
===
- support recursive locks in dbus_threads_init_default()
- update AUTHORS
- the README, FAQ, and probably other places talk about 1.0 and ABI guarantees,
......@@ -142,6 +140,8 @@ Can Be Post 1.0
- just before 1.0, try a HAVE_INT64=0 build and be sure it runs
- Windows port needs recursive mutexes
Should Be Post 1.0
===
......
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