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-rw-r--r--src/thread/pthread_cond_timedwait.c43
1 files changed, 38 insertions, 5 deletions
diff --git a/src/thread/pthread_cond_timedwait.c b/src/thread/pthread_cond_timedwait.c
index 0a80d305..5f29a249 100644
--- a/src/thread/pthread_cond_timedwait.c
+++ b/src/thread/pthread_cond_timedwait.c
@@ -32,7 +32,7 @@ struct waiter {
int *notify;
pthread_mutex_t *mutex;
pthread_cond_t *cond;
- int shared;
+ int shared, err;
};
/* Self-synchronized-destruction-safe lock functions */
@@ -73,6 +73,11 @@ static void unwait(void *arg)
if (node->shared) {
pthread_cond_t *c = node->cond;
pthread_mutex_t *m = node->mutex;
+ /* Suppress cancellation if a signal was potentially
+ * consumed; this is a legitimate form of spurious
+ * wake even if not. */
+ if (node->err == ECANCELED && c->_c_seq != node->state)
+ node->err = 0;
if (a_fetch_add(&c->_c_waiters, -1) == -0x7fffffff)
__wake(&c->_c_waiters, 1, 0);
node->mutex_ret = pthread_mutex_lock(m);
@@ -121,12 +126,23 @@ static void unwait(void *arg)
} else {
a_dec(&node->mutex->_m_waiters);
}
+
+ /* Since a signal was consumed, acting on cancellation is not
+ * permitted. The only other error possible at this stage,
+ * ETIMEDOUT, is permitted even if a signal was consumed. */
+ if (node->err = ECANCELED) node->err = 0;
}
+static void dummy(void *arg)
+{
+}
+
+int __pthread_setcancelstate(int, int *);
+
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;
+ int e, seq, *fut, clock = c->_c_clock, cs;
if ((m->_m_type&15) && (m->_m_lock&INT_MAX) != __pthread_self()->tid)
return EPERM;
@@ -139,7 +155,7 @@ int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restri
if (c->_c_shared) {
node.shared = 1;
fut = &c->_c_seq;
- seq = c->_c_seq;
+ seq = node.state = c->_c_seq;
a_inc(&c->_c_waiters);
} else {
lock(&c->_c_lock);
@@ -157,13 +173,30 @@ int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restri
__pthread_mutex_unlock(m);
- do e = __timedwait(fut, seq, clock, ts, unwait, &node, !node.shared);
+ __pthread_setcancelstate(PTHREAD_CANCEL_MASKED, &cs);
+
+ do e = __timedwait(fut, seq, clock, ts, dummy, 0, !node.shared);
while (*fut==seq && (!e || e==EINTR));
if (e == EINTR) e = 0;
+ node.err = e;
unwait(&node);
+ e = node.err;
+
+ /* Suppress cancellation if there was an error locking the mutex,
+ * since the contract for cancellation requires the mutex to be
+ * locked when the cleanup handler is called, and there is no
+ * way to report an error. */
+ if (node.mutex_ret) e = node.mutex_ret;
+
+ __pthread_setcancelstate(cs, 0);
+
+ if (e == ECANCELED) {
+ __pthread_testcancel();
+ __pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, 0);
+ }
- return node.mutex_ret ? node.mutex_ret : e;
+ return e;
}
int __private_cond_signal(pthread_cond_t *c, int n)