zircon/third_party/ulib/musl/pthread/pthread_mutex_timedlock.c

#include "atomic.h"
#include "threads_impl.h"

int pthread_mutex_timedlock(pthread_mutex_t* restrict m, const struct timespec* restrict at) {
  int type = pthread_mutex_get_type(m);

  if ((type == PTHREAD_MUTEX_NORMAL) &&
      !a_cas_shim(&m->_m_lock, 0, pthread_mutex_tid_to_uncontested_state(__thread_get_tid())))
    return 0;

  int r, t;

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

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

  while ((r = pthread_mutex_trylock(m)) == EBUSY) {
    if (!(r = atomic_load(&m->_m_lock)))
      continue;

    if ((type == PTHREAD_MUTEX_ERRORCHECK) &&
        (pthread_mutex_state_to_tid(r) == __thread_get_tid())) {
      return EDEADLK;
    }

    atomic_fetch_add(&m->_m_waiters, 1);
    t = pthread_mutex_uncontested_to_contested_state(r);
    a_cas_shim(&m->_m_lock, r, t);

    zx_handle_t new_owner =
        pthread_mutex_prio_inherit(m) ? pthread_mutex_state_to_tid(t) : ZX_HANDLE_INVALID;
    r = __timedwait_assign_owner(&m->_m_lock, t, CLOCK_REALTIME, at, new_owner);

    atomic_fetch_sub(&m->_m_waiters, 1);
    if (r)
      break;
  }
  return r;
}