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| | #include <semaphore.h>
#include "pthread_impl.h"
static void cleanup(void *p)
{
a_dec(p);
}
int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict at)
{
pthread_testcancel();
if (!sem_trywait(sem)) return 0;
int spins = 100;
while (spins-- && sem->__val[0] <= 0 && !sem->__val[1]) a_spin();
while (sem_trywait(sem)) {
int r;
a_inc(sem->__val+1);
a_cas(sem->__val, 0, -1);
pthread_cleanup_push(cleanup, (void *)(sem->__val+1));
r = __timedwait_cp(sem->__val, -1, CLOCK_REALTIME, at, sem->__val[2]);
pthread_cleanup_pop(1);
/* Linux pre-2.6.22 bug: Sometimes SYS_futex returns with EINTR when it should not.
* Workaround: Retry on EINTR unless someone installed handlers before.
*/
if (r && (r != EINTR || libc.handling_sigs)) {
errno = r;
return -1;
}
}
return 0;
}
|