implement robust mutexes
[musl] / src / thread / pthread_mutex_unlock.c
1 #include "pthread_impl.h"
2
3 int pthread_mutex_unlock(pthread_mutex_t *m)
4 {
5         pthread_t self;
6
7         if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
8                 self = __pthread_self();
9                 if ((m->_m_lock&0x1fffffff) != self->tid)
10                         return EPERM;
11                 if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
12                         return 0;
13                 if (m->_m_type >= 4) {
14                         self->robust_list.pending = &m->_m_next;
15                         *(void **)m->_m_prev = m->_m_next;
16                         if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
17                 }
18         }
19
20         m->_m_lock = 0;
21         if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);
22         if (m->_m_type >= 4) self->robust_list.pending = 0;
23         return 0;
24 }