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#include "pthread_impl.h"
int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
{
int old, own;
int type = m->_m_type;
pthread_t self = __pthread_self();
int tid = self->tid;
old = m->_m_lock;
own = old & 0x3fffffff;
if (own == tid) {
if ((type&8) && m->_m_count<0) {
old &= 0x40000000;
m->_m_count = 0;
goto success;
}
if ((type&3) == PTHREAD_MUTEX_RECURSIVE) {
if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
m->_m_count++;
return 0;
}
}
if (own == 0x3fffffff) return ENOTRECOVERABLE;
if (own || (old && !(type & 4))) return EBUSY;
if (type & 128) {
if (!self->robust_list.off) {
self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
__syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
}
if (m->_m_waiters) tid |= 0x80000000;
self->robust_list.pending = &m->_m_next;
}
tid |= old & 0x40000000;
if (a_cas(&m->_m_lock, old, tid) != old) {
self->robust_list.pending = 0;
if ((type&12)==12 && m->_m_waiters) return ENOTRECOVERABLE;
return EBUSY;
}
success:
if ((type&8) && m->_m_waiters) {
int priv = (type & 128) ^ 128;
__syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
self->robust_list.pending = 0;
return (type&4) ? ENOTRECOVERABLE : EBUSY;
}
volatile void *next = self->robust_list.head;
m->_m_next = next;
m->_m_prev = &self->robust_list.head;
if (next != &self->robust_list.head) *(volatile void *volatile *)
((char *)next - sizeof(void *)) = &m->_m_next;
self->robust_list.head = &m->_m_next;
self->robust_list.pending = 0;
if (old) {
m->_m_count = 0;
return EOWNERDEAD;
}
return 0;
}
int __pthread_mutex_trylock(pthread_mutex_t *m)
{
if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
return __pthread_mutex_trylock_owner(m);
}
weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);
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