1 #include "pthread_impl.h"
2
pthread_mutex_timedlock_pi(pthread_mutex_t * restrict m,const struct timespec * restrict at)3 static int pthread_mutex_timedlock_pi(pthread_mutex_t *restrict m, const struct timespec *restrict at)
4 {
5 int type = m->_m_type;
6 int priv = (type & 128) ^ 128;
7 pthread_t self = __pthread_self();
8 int e;
9
10 if (!priv) self->robust_list.pending = &m->_m_next;
11
12 do e = -__syscall(SYS_futex, &m->_m_lock, FUTEX_LOCK_PI|priv, 0, at);
13 while (e==EINTR);
14 if (e) self->robust_list.pending = 0;
15
16 switch (e) {
17 case 0:
18 /* Catch spurious success for non-robust mutexes. */
19 if (!(type&4) && ((m->_m_lock & 0x40000000) || m->_m_waiters)) {
20 a_store(&m->_m_waiters, -1);
21 __syscall(SYS_futex, &m->_m_lock, FUTEX_UNLOCK_PI|priv);
22 self->robust_list.pending = 0;
23 break;
24 }
25 /* Signal to trylock that we already have the lock. */
26 m->_m_count = -1;
27 return __pthread_mutex_trylock(m);
28 case ETIMEDOUT:
29 return e;
30 case EDEADLK:
31 if ((type&3) == PTHREAD_MUTEX_ERRORCHECK) return e;
32 }
33 do e = __timedwait(&(int){0}, 0, CLOCK_REALTIME, at, 1);
34 while (e != ETIMEDOUT);
35 return e;
36 }
37
__pthread_mutex_timedlock(pthread_mutex_t * restrict m,const struct timespec * restrict at)38 int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec *restrict at)
39 {
40 if ((m->_m_type&15) == PTHREAD_MUTEX_NORMAL
41 && !a_cas(&m->_m_lock, 0, EBUSY))
42 return 0;
43
44 int type = m->_m_type;
45 int r, t, priv = (type & 128) ^ 128;
46
47 r = __pthread_mutex_trylock(m);
48 if (r != EBUSY) return r;
49
50 if (type&8) return pthread_mutex_timedlock_pi(m, at);
51
52 int spins = 100;
53 while (spins-- && m->_m_lock && !m->_m_waiters) a_spin();
54
55 while ((r=__pthread_mutex_trylock(m)) == EBUSY) {
56 r = m->_m_lock;
57 int own = r & 0x3fffffff;
58 if (!own && (!r || (type&4)))
59 continue;
60 if ((type&3) == PTHREAD_MUTEX_ERRORCHECK
61 && own == __pthread_self()->tid)
62 return EDEADLK;
63
64 a_inc(&m->_m_waiters);
65 t = r | 0x80000000;
66 a_cas(&m->_m_lock, r, t);
67 r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, priv);
68 a_dec(&m->_m_waiters);
69 if (r && r != EINTR) break;
70 }
71 return r;
72 }
73
74 weak_alias(__pthread_mutex_timedlock, pthread_mutex_timedlock);
75