int
xp_sem_timedwait(xp_sem_t *sem, const struct timespec *abs_timeout)
{
int retval=0;
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
while ((*sem)->count == 0) {
(*sem)->nwaiters++;
retval=pthread_cond_timedwait(&(*sem)->gtzero, &(*sem)->lock, abs_timeout);
(*sem)->nwaiters--;
if(retval) {
errno=retval;
retval=-1;
break;
}
}
if(retval==0)
(*sem)->count--;
pthread_mutex_unlock(&(*sem)->lock);
RETURN:
return retval;
}
int
xp_sem_post(xp_sem_t *sem)
{
int retval;
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
(*sem)->count++;
if ((*sem)->nwaiters > 0) {
/*
* We must use pthread_cond_broadcast() rather than
* pthread_cond_signal() in order to assure that the highest
* priority thread is run by the scheduler, since
* pthread_cond_signal() signals waiting threads in FIFO order.
*/
pthread_cond_broadcast(&(*sem)->gtzero);
}
pthread_mutex_unlock(&(*sem)->lock);
retval = 0;
RETURN:
return retval;
}
int
xp_sem_destroy(xp_sem_t *sem)
{
int retval;
_SEM_CHECK_VALIDITY(sem);
/* Make sure there are no waiters. */
pthread_mutex_lock(&(*sem)->lock);
if ((*sem)->nwaiters > 0) {
pthread_mutex_unlock(&(*sem)->lock);
errno = EBUSY;
retval = -1;
goto RETURN;
}
pthread_mutex_unlock(&(*sem)->lock);
while(pthread_mutex_destroy(&(*sem)->lock)==EBUSY)
SLEEP(1);
while(pthread_cond_destroy(&(*sem)->gtzero)==EBUSY)
SLEEP(1);
(*sem)->magic = 0;
free(*sem);
retval = 0;
RETURN:
return retval;
}
int
_sem_post(sem_t *sem)
{
int retval;
_SEM_CHECK_VALIDITY(sem);
/*
* sem_post() is required to be safe to call from within signal
* handlers. Thus, we must defer signals.
*/
_thread_kern_sig_defer();
pthread_mutex_lock(&(*sem)->lock);
(*sem)->count++;
if ((*sem)->nwaiters > 0)
pthread_cond_signal(&(*sem)->gtzero);
pthread_mutex_unlock(&(*sem)->lock);
_thread_kern_sig_undefer();
retval = 0;
RETURN:
return retval;
}
int
_sem_wait(sem_t *sem)
{
int retval;
_thread_enter_cancellation_point();
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
while ((*sem)->count == 0) {
(*sem)->nwaiters++;
pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
(*sem)->nwaiters--;
}
(*sem)->count--;
pthread_mutex_unlock(&(*sem)->lock);
retval = 0;
RETURN:
_thread_leave_cancellation_point();
return retval;
}
int
sem_wait(sem_t *sem)
{
int retval;
pthread_testcancel();
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
while ((*sem)->count == 0) {
(*sem)->nwaiters++;
pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
(*sem)->nwaiters--;
}
(*sem)->count--;
pthread_mutex_unlock(&(*sem)->lock);
retval = 0;
RETURN:
pthread_testcancel();
return retval;
}
int
xp_sem_getvalue(xp_sem_t *sem, int *sval)
{
int retval;
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
*sval = (int)(*sem)->count;
pthread_mutex_unlock(&(*sem)->lock);
retval = 0;
RETURN:
return retval;
}
int
xp_sem_trywait(xp_sem_t *sem)
{
int retval;
_SEM_CHECK_VALIDITY(sem);
pthread_mutex_lock(&(*sem)->lock);
if ((*sem)->count > 0) {
(*sem)->count--;
retval = 0;
} else {
errno = EAGAIN;
retval = -1;
}
pthread_mutex_unlock(&(*sem)->lock);
RETURN:
return retval;
}