1#include "pthread_impl.h"
2
3int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
4{
5	int old, own;
6	int type = m->_m_type & 15;
7	pthread_t self = __pthread_self();
8	int tid = self->tid;
9
10	old = m->_m_lock;
11	own = old & 0x7fffffff;
12	if (own == tid && (type&3) == PTHREAD_MUTEX_RECURSIVE) {
13		if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
14		m->_m_count++;
15		return 0;
16	}
17	if (own == 0x7fffffff) return ENOTRECOVERABLE;
18
19	if (m->_m_type & 128) {
20		if (!self->robust_list.off) {
21			self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
22			__syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
23		}
24		if (m->_m_waiters) tid |= 0x80000000;
25		self->robust_list.pending = &m->_m_next;
26	}
27
28	if ((own && (!(own & 0x40000000) || !(type & 4)))
29	    || a_cas(&m->_m_lock, old, tid) != old) {
30		self->robust_list.pending = 0;
31		return EBUSY;
32	}
33
34	volatile void *next = self->robust_list.head;
35	m->_m_next = next;
36	m->_m_prev = &self->robust_list.head;
37	if (next != &self->robust_list.head) *(volatile void *volatile *)
38		((char *)next - sizeof(void *)) = &m->_m_next;
39	self->robust_list.head = &m->_m_next;
40	self->robust_list.pending = 0;
41
42	if (own) {
43		m->_m_count = 0;
44		m->_m_type |= 8;
45		return EOWNERDEAD;
46	}
47
48	return 0;
49}
50
51int __pthread_mutex_trylock(pthread_mutex_t *m)
52{
53	if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
54		return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
55	return __pthread_mutex_trylock_owner(m);
56}
57
58weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);
59