summaryrefslogblamecommitdiff
path: root/src/thread/sem_timedwait.c
blob: 8132eb1bf7a276d9b2dd2c9c978bbc0f0b29b7f4 (plain) (tree)
1
2
3
4
5
6
7
8
9


                         




                            
                                                                          
 

                             


                                        
                                                                         
 

                                  

                                         
                                                                      

                                                                                      
                                      
                                  
                                  
                 
         
                 
 
#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);
		if (r && r != EINTR) {
			errno = r;
			return -1;
		}
	}
	return 0;
}