fusl/src/thread/pthread_mutex_timedlock.c

#include "pthread_impl.h"

int __pthread_mutex_timedlock(pthread_mutex_t* restrict m,
                              const struct timespec* restrict at) {
  if ((m->_m_type & 15) == PTHREAD_MUTEX_NORMAL &&
      !a_cas(&m->_m_lock, 0, EBUSY))
    return 0;

  int r, t, priv = (m->_m_type & 128) ^ 128;

  r = pthread_mutex_trylock(m);
  if (r != EBUSY)
    return r;

  int spins = 100;
  while (spins-- && m->_m_lock && !m->_m_waiters)
    a_spin();

  while ((r = pthread_mutex_trylock(m)) == EBUSY) {
    if (!(r = m->_m_lock) || ((r & 0x40000000) && (m->_m_type & 4)))
      continue;
    if ((m->_m_type & 3) == PTHREAD_MUTEX_ERRORCHECK &&
        (r & 0x7fffffff) == __pthread_self()->tid)
      return EDEADLK;

    a_inc(&m->_m_waiters);
    t = r | 0x80000000;
    a_cas(&m->_m_lock, r, t);
    r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, priv);
    a_dec(&m->_m_waiters);
    if (r && r != EINTR)
      break;
  }
  return r;
}

weak_alias(__pthread_mutex_timedlock, pthread_mutex_timedlock);