X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fthread%2Fpthread_cond_timedwait.c;h=6b761455c47f0f8c8afde4e2d57768208efc06ba;hb=1e4204d522670a1d8b8ab85f1cfefa960547e8af;hp=c5cf66c35b28f135f54222a0b105b76cb25fec6c;hpb=4992ace94232a116bdca25481ccc3d6841b83432;p=musl

diff --git a/src/thread/pthread_cond_timedwait.c b/src/thread/pthread_cond_timedwait.c
index c5cf66c3..6b761455 100644
--- a/src/thread/pthread_cond_timedwait.c
+++ b/src/thread/pthread_cond_timedwait.c
@@ -24,11 +24,8 @@
 
 struct waiter {
 	struct waiter *prev, *next;
-	int state, barrier, mutex_ret;
-	int *notify;
-	pthread_mutex_t *mutex;
-	pthread_cond_t *cond;
-	int shared;
+	volatile int state, barrier;
+	volatile int *notify;
 };
 
 /* Self-synchronized-destruction-safe lock functions */
@@ -52,7 +49,7 @@ static inline void unlock_requeue(volatile int *l, volatile int *r, int w)
 {
 	a_store(l, 0);
 	if (w) __wake(l, 1, 1);
-	else __syscall(SYS_futex, l, FUTEX_REQUEUE|128, 0, 1, r) != -EINVAL
+	else __syscall(SYS_futex, l, FUTEX_REQUEUE|FUTEX_PRIVATE, 0, 1, r) != -ENOSYS
 		|| __syscall(SYS_futex, l, FUTEX_REQUEUE, 0, 1, r);
 }
 
@@ -62,20 +59,60 @@ enum {
 	LEAVING,
 };
 
-static void unwait(void *arg)
+int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restrict m, const struct timespec *restrict ts)
 {
-	struct waiter *node = arg;
+	struct waiter node = { 0 };
+	int e, seq, clock = c->_c_clock, cs, shared=0, oldstate, tmp;
+	volatile int *fut;
 
-	if (node->shared) {
-		pthread_cond_t *c = node->cond;
-		pthread_mutex_t *m = node->mutex;
+	if ((m->_m_type&15) && (m->_m_lock&INT_MAX) != __pthread_self()->tid)
+		return EPERM;
+
+	if (ts && ts->tv_nsec >= 1000000000UL)
+		return EINVAL;
+
+	__pthread_testcancel();
+
+	if (c->_c_shared) {
+		shared = 1;
+		fut = &c->_c_seq;
+		seq = c->_c_seq;
+		a_inc(&c->_c_waiters);
+	} else {
+		lock(&c->_c_lock);
+
+		seq = node.barrier = 2;
+		fut = &node.barrier;
+		node.state = WAITING;
+		node.next = c->_c_head;
+		c->_c_head = &node;
+		if (!c->_c_tail) c->_c_tail = &node;
+		else node.next->prev = &node;
+
+		unlock(&c->_c_lock);
+	}
+
+	__pthread_mutex_unlock(m);
+
+	__pthread_setcancelstate(PTHREAD_CANCEL_MASKED, &cs);
+	if (cs == PTHREAD_CANCEL_DISABLE) __pthread_setcancelstate(cs, 0);
+
+	do e = __timedwait_cp(fut, seq, clock, ts, !shared);
+	while (*fut==seq && (!e || e==EINTR));
+	if (e == EINTR) e = 0;
+
+	if (shared) {
+		/* Suppress cancellation if a signal was potentially
+		 * consumed; this is a legitimate form of spurious
+		 * wake even if not. */
+		if (e == ECANCELED && c->_c_seq != seq) e = 0;
 		if (a_fetch_add(&c->_c_waiters, -1) == -0x7fffffff)
 			__wake(&c->_c_waiters, 1, 0);
-		node->mutex_ret = pthread_mutex_lock(m);
-		return;
+		oldstate = WAITING;
+		goto relock;
 	}
 
-	int oldstate = a_cas(&node->state, WAITING, LEAVING);
+	oldstate = a_cas(&node.state, WAITING, LEAVING);
 
 	if (oldstate == WAITING) {
 		/* Access to cv object is valid because this waiter was not
@@ -83,89 +120,64 @@ static void unwait(void *arg)
 		 * after seeing a LEAVING waiter without getting notified
 		 * via the futex notify below. */
 
-		pthread_cond_t *c = node->cond;
 		lock(&c->_c_lock);
 		
-		if (c->_c_head == node) c->_c_head = node->next;
-		else if (node->prev) node->prev->next = node->next;
-		if (c->_c_tail == node) c->_c_tail = node->prev;
-		else if (node->next) node->next->prev = node->prev;
+		if (c->_c_head == &node) c->_c_head = node.next;
+		else if (node.prev) node.prev->next = node.next;
+		if (c->_c_tail == &node) c->_c_tail = node.prev;
+		else if (node.next) node.next->prev = node.prev;
 		
 		unlock(&c->_c_lock);
 
-		if (node->notify) {
-			if (a_fetch_add(node->notify, -1)==1)
-				__wake(node->notify, 1, 1);
+		if (node.notify) {
+			if (a_fetch_add(node.notify, -1)==1)
+				__wake(node.notify, 1, 1);
 		}
 	} else {
 		/* Lock barrier first to control wake order. */
-		lock(&node->barrier);
+		lock(&node.barrier);
 	}
 
-	node->mutex_ret = pthread_mutex_lock(node->mutex);
+relock:
+	/* Errors locking the mutex override any existing error or
+	 * cancellation, since the caller must see them to know the
+	 * state of the mutex. */
+	if ((tmp = pthread_mutex_lock(m))) e = tmp;
 
-	if (oldstate == WAITING) return;
+	if (oldstate == WAITING) goto done;
 
-	if (!node->next) a_inc(&node->mutex->_m_waiters);
+	if (!node.next && !(m->_m_type & 8))
+		a_inc(&m->_m_waiters);
 
 	/* Unlock the barrier that's holding back the next waiter, and
 	 * either wake it or requeue it to the mutex. */
-	if (node->prev) {
-		unlock_requeue(&node->prev->barrier,
-			&node->mutex->_m_lock,
-			node->mutex->_m_type & 128);
-	} else {
-		a_dec(&node->mutex->_m_waiters);
+	if (node.prev) {
+		int val = m->_m_lock;
+		if (val>0) a_cas(&m->_m_lock, val, val|0x80000000);
+		unlock_requeue(&node.prev->barrier, &m->_m_lock, m->_m_type & (8|128));
+	} else if (!(m->_m_type & 8)) {
+		a_dec(&m->_m_waiters);		
 	}
-}
-
-int pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restrict m, const struct timespec *restrict ts)
-{
-	struct waiter node = { .cond = c, .mutex = m };
-	int e, seq, *fut, clock = c->_c_clock;
-
-	if ((m->_m_type&15) && (m->_m_lock&INT_MAX) != __pthread_self()->tid)
-		return EPERM;
 
-	if (ts && ts->tv_nsec >= 1000000000UL)
-		return EINVAL;
-
-	pthread_testcancel();
-
-	if (c->_c_shared) {
-		node.shared = 1;
-		fut = &c->_c_seq;
-		seq = c->_c_seq;
-		a_inc(&c->_c_waiters);
-	} else {
-		lock(&c->_c_lock);
+	/* Since a signal was consumed, cancellation is not permitted. */
+	if (e == ECANCELED) e = 0;
 
-		seq = node.barrier = 2;
-		fut = &node.barrier;
-		node.state = WAITING;
-		node.next = c->_c_head;
-		c->_c_head = &node;
-		if (!c->_c_tail) c->_c_tail = &node;
-		else node.next->prev = &node;
+done:
+	__pthread_setcancelstate(cs, 0);
 
-		unlock(&c->_c_lock);
+	if (e == ECANCELED) {
+		__pthread_testcancel();
+		__pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, 0);
 	}
 
-	pthread_mutex_unlock(m);
-
-	do e = __timedwait(fut, seq, clock, ts, unwait, &node, !node.shared);
-	while (*fut==seq && (!e || e==EINTR));
-	if (e == EINTR) e = 0;
-
-	unwait(&node);
-
-	return node.mutex_ret ? node.mutex_ret : e;
+	return e;
 }
 
 int __private_cond_signal(pthread_cond_t *c, int n)
 {
 	struct waiter *p, *first=0;
-	int ref = 0, cur;
+	volatile int ref = 0;
+	int cur;
 
 	lock(&c->_c_lock);
 	for (p=c->_c_tail; n && p; p=p->prev) {
@@ -197,3 +209,5 @@ int __private_cond_signal(pthread_cond_t *c, int n)
 
 	return 0;
 }
+
+weak_alias(__pthread_cond_timedwait, pthread_cond_timedwait);