fusl/src/thread/sem_timedwait.c

#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;
}