src/thread/pthread_mutex_timedlock.c


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#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 type = m->_m_type;
	int r, t, priv = (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) {
		r = m->_m_lock;
		int own = r & 0x3fffffff;
		if (!own && (!r || (type&4)))
			continue;
		if ((type&3) == PTHREAD_MUTEX_ERRORCHECK
		    && own == __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);