1 #include "pthread_impl.h"
2
__pthread_mutex_trylock_owner(pthread_mutex_t * m)3 int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
4 {
5 int old, own;
6 int type = m->_m_type;
7 pthread_t self = __pthread_self();
8 int tid = self->tid;
9
10 old = m->_m_lock;
11 own = old & 0x3fffffff;
12 #ifdef __LITEOS_A__
13 if (own == tid) {
14 if ((type&PTHREAD_MUTEX_TYPE_MASK) == PTHREAD_MUTEX_RECURSIVE) {
15 if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
16 m->_m_count++;
17 return 0;
18 }
19 }
20 #else
21 if (__is_mutex_destroyed(m->_m_type))
22 __handle_using_destroyed_mutex(m, __FUNCTION__);
23 if (own == tid) {
24 if ((type&8) && m->_m_count<0) {
25 old &= 0x40000000;
26 m->_m_count = 0;
27 goto success;
28 }
29 if ((type&3) == PTHREAD_MUTEX_RECURSIVE) {
30 if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
31 m->_m_count++;
32 return 0;
33 }
34 }
35 #endif
36 if (own == 0x3fffffff) return ENOTRECOVERABLE;
37 if (own || (old && !(type & 4))) return EBUSY;
38
39 if (type & 128) {
40 if (!self->robust_list.off) {
41 self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
42 #ifndef __LITEOS_A__
43 __syscall(SYS_set_robust_list, &self->robust_list, 3*sizeof(long));
44 #endif
45 }
46 if (m->_m_waiters) tid |= 0x80000000;
47 self->robust_list.pending = &m->_m_next;
48 }
49 tid |= old & 0x40000000;
50
51 if (a_cas(&m->_m_lock, old, tid) != old) {
52 self->robust_list.pending = 0;
53 #ifndef __LITEOS_A__
54 if ((type&12)==12 && m->_m_waiters) return ENOTRECOVERABLE;
55 #endif
56 return EBUSY;
57 }
58
59 #ifndef __LITEOS_A__
60 success:
61 if ((type&8) && m->_m_waiters) {
62 int priv = (type & 128) ^ 128;
63 __syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
64 self->robust_list.pending = 0;
65 return (type&4) ? ENOTRECOVERABLE : EBUSY;
66 }
67 #endif
68
69 volatile void *next = self->robust_list.head;
70 m->_m_next = next;
71 m->_m_prev = &self->robust_list.head;
72 if (next != &self->robust_list.head) *(volatile void *volatile *)
73 ((char *)next - sizeof(void *)) = &m->_m_next;
74 self->robust_list.head = &m->_m_next;
75 self->robust_list.pending = 0;
76
77 if (old) {
78 m->_m_count = 0;
79 return EOWNERDEAD;
80 }
81
82 return 0;
83 }
84
__pthread_mutex_trylock(pthread_mutex_t * m)85 int __pthread_mutex_trylock(pthread_mutex_t *m)
86 {
87 if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL)
88 return a_cas(&m->_m_lock, 0, EBUSY) & EBUSY;
89 return __pthread_mutex_trylock_owner(m);
90 }
91
92 weak_alias(__pthread_mutex_trylock, pthread_mutex_trylock);
93