nsz Git - musl/blob - 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         int waiters = m->_m_waiters;
   7         int cont;
   8         int type = m->_m_type & 15;
   9         int priv = (m->_m_type & 128) ^ 128;
  10
  11         if (type != PTHREAD_MUTEX_NORMAL) {
  12                 self = __pthread_self();
  13                 if ((m->_m_lock&0x7fffffff) != self->tid)
  14                         return EPERM;
  15                 if ((type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
  16                         return m->_m_count--, 0;
  17                 if (!priv) {
  18                         self->robust_list.pending = &m->_m_next;
  19                         __vm_lock();
  20                 }
  21                 volatile void *prev = m->_m_prev;
  22                 volatile void *next = m->_m_next;
  23                 *(volatile void *volatile *)prev = next;
  24                 if (next != &self->robust_list.head) *(volatile void *volatile *)
  25                         ((char *)next - sizeof(void *)) = prev;
  26         }
  27         cont = a_swap(&m->_m_lock, (type & 8) ? 0x7fffffff : 0);
  28         if (type != PTHREAD_MUTEX_NORMAL && !priv) {
  29                 self->robust_list.pending = 0;
  30                 __vm_unlock();
  31         }
  32         if (waiters || cont<0)
  33                 __wake(&m->_m_lock, 1, priv);
  34         return 0;
  35 }
  36
  37 weak_alias(__pthread_mutex_unlock, pthread_mutex_unlock);