1 files changed, 50 insertions, 9 deletions

diff --git a/lib/libpthread/thread/thr_once.c b/lib/libpthread/thread/thr_once.c
index 152fdec7b407..ad158d13e599 100644
--- a/lib/libpthread/thread/thr_once.c
+++ b/lib/libpthread/thread/thr_once.c
@@ -38,18 +38,59 @@
 
 __weak_reference(_pthread_once, pthread_once);
 
+#define ONCE_NEVER_DONE		PTHREAD_NEEDS_INIT
+#define ONCE_DONE		PTHREAD_DONE_INIT
+#define	ONCE_IN_PROGRESS	0x02
+#define	ONCE_MASK		0x03
+
+static pthread_mutex_t		once_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t		once_cv = PTHREAD_COND_INITIALIZER;
+
+/*
+ * POSIX:
+ * The pthread_once() function is not a cancellation point. However,
+ * if init_routine is a cancellation point and is canceled, the effect
+ * on once_control shall be as if pthread_once() was never called.
+ */
+ 
+static void
+once_cancel_handler(void *arg)
+{
+	pthread_once_t *once_control = arg;
+
+	_pthread_mutex_lock(&once_lock);
+	once_control->state = ONCE_NEVER_DONE;
+	_pthread_mutex_unlock(&once_lock);
+	_pthread_cond_broadcast(&once_cv);
+}
+
 int
 _pthread_once(pthread_once_t *once_control, void (*init_routine) (void))
 {
-	if (once_control->state == PTHREAD_NEEDS_INIT) {
-		if (_thr_initial == NULL)
-			_libpthread_init(NULL);
-		_pthread_mutex_lock(&(once_control->mutex));
-		if (once_control->state == PTHREAD_NEEDS_INIT) {
-			init_routine();
-			once_control->state = PTHREAD_DONE_INIT;
-		}
-		_pthread_mutex_unlock(&(once_control->mutex));
+	int wakeup = 0;
+
+	if (once_control->state == ONCE_DONE)
+		return (0);
+	_pthread_mutex_lock(&once_lock);
+	while (*(volatile int *)&(once_control->state) == ONCE_IN_PROGRESS)
+		_pthread_cond_wait(&once_cv, &once_lock);
+	/*
+	 * If previous thread was canceled, then the state still
+	 * could be ONCE_NEVER_DONE, we need to check it again.
+	 */
+	if (*(volatile int *)&(once_control->state) == ONCE_NEVER_DONE) {
+		once_control->state = ONCE_IN_PROGRESS;
+		_pthread_mutex_unlock(&once_lock);
+		_pthread_cleanup_push(once_cancel_handler, once_control);
+		init_routine();
+		_pthread_cleanup_pop(0);
+		_pthread_mutex_lock(&once_lock);
+		once_control->state = ONCE_DONE;
+		wakeup = 1;
 	}
+	_pthread_mutex_unlock(&once_lock);
+	if (wakeup)
+		_pthread_cond_broadcast(&once_cv);
 	return (0);
 }
+