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#include "pthread_impl.h"
struct cm {
pthread_cond_t *c;
pthread_mutex_t *m;
};
static void unwait(pthread_cond_t *c, pthread_mutex_t *m)
{
int w;
/* Removing a waiter is non-trivial if we could be using requeue
* based broadcast signals, due to mutex access issues, etc. */
if (c->_c_mutex == (void *)-1) {
a_dec(&c->_c_waiters);
return;
}
while (a_swap(&c->_c_lock, 1))
__wait(&c->_c_lock, &c->_c_lockwait, 1, 1);
/* Atomically decrement waiters2 if positive, else mutex waiters. */
do w = c->_c_waiters2;
while (w && a_cas(&c->_c_waiters2, w, w-1)!=w);
if (!w) a_dec(&m->_m_waiters);
a_store(&c->_c_lock, 0);
if (c->_c_lockwait) __wake(&c->_c_lock, 1, 1);
}
static void cleanup(void *p)
{
struct cm *cm = p;
unwait(cm->c, cm->m);
pthread_mutex_lock(cm->m);
}
int pthread_cond_timedwait(pthread_cond_t *c, pthread_mutex_t *m, const struct timespec *ts)
{
struct cm cm = { .c=c, .m=m };
int r, e=0, seq;
if (ts && ts->tv_nsec >= 1000000000UL)
return EINVAL;
pthread_testcancel();
if (c->_c_mutex != (void *)-1) c->_c_mutex = m;
a_inc(&c->_c_waiters);
a_inc(&c->_c_waiters2);
seq = c->_c_seq;
if ((r=pthread_mutex_unlock(m))) return r;
do e = __timedwait(&c->_c_seq, seq, c->_c_clock, ts, cleanup, &cm, 0);
while (c->_c_seq == seq && (!e || e==EINTR));
if (e == EINTR) e = 0;
unwait(c, m);
if ((r=pthread_mutex_lock(m))) return r;
return e;
}
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