src/thread/pthread_mutex_timedlock.c

   1 #include "pthread_impl.h"
   2
   3 int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec *restrict at)
   4 {
   5         if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL
   6             && !a_cas(&m->_m_lock, 0, EBUSY))
   7                 return 0;
   8
   9         int r, t, priv = (m->_m_type & 128) ^ 128;
  10
  11         r = pthread_mutex_trylock(m);
  12         if (r != EBUSY) return r;
  13
  14         int spins = 100;
  15         while (spins-- && m->_m_lock && !m->_m_waiters) a_spin();
  16
  17         while ((r=pthread_mutex_trylock(m)) == EBUSY) {
  18                 if (!(r=m->_m_lock) || ((r&0x40000000) && (m->_m_type&4)))
  19                         continue;
  20                 if ((m->_m_type&3) == PTHREAD_MUTEX_ERRORCHECK
  21                  && (r&0x7fffffff) == __pthread_self()->tid)
  22                         return EDEADLK;
  23
  24                 a_inc(&m->_m_waiters);
  25                 t = r | 0x80000000;
  26                 a_cas(&m->_m_lock, r, t);
  27                 r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, 0, 0, priv);
  28                 a_dec(&m->_m_waiters);
  29                 if (r && r != EINTR) break;
  30         }
  31         return r;
  32 }
  33
  34 weak_alias(__pthread_mutex_timedlock, pthread_mutex_timedlock);