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