nsz Git - musl/blob - src/thread/pthread_mutex_unlock.c

   1 #include "pthread_impl.h"
   2
   3 void __vm_lock_impl(int);
   4 void __vm_unlock_impl(void);
   5
   6 int pthread_mutex_unlock(pthread_mutex_t *m)
   7 {
   8         pthread_t self;
   9         int waiters = m->_m_waiters;
  10         int cont;
  11         int robust = 0;
  12
  13         if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
  14                 if (!m->_m_lock)
  15                         return EPERM;
  16                 self = pthread_self();
  17                 if ((m->_m_lock&0x1fffffff) != self->tid)
  18                         return EPERM;
  19                 if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
  20                         return m->_m_count--, 0;
  21                 if (m->_m_type >= 4) {
  22                         robust = 1;
  23                         self->robust_list.pending = &m->_m_next;
  24                         *(void **)m->_m_prev = m->_m_next;
  25                         if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
  26                         __vm_lock_impl(+1);
  27                 }
  28         }
  29         cont = a_swap(&m->_m_lock, 0);
  30         if (robust) {
  31                 self->robust_list.pending = 0;
  32                 __vm_unlock_impl();
  33         }
  34         if (waiters || cont<0)
  35                 __wake(&m->_m_lock, 1, 0);
  36         return 0;
  37 }