fusl/src/thread/pthread_mutex_unlock.c

#include "pthread_impl.h"

int __pthread_mutex_unlock(pthread_mutex_t* m) {
  pthread_t self;
  int waiters = m->_m_waiters;
  int cont;
  int type = m->_m_type & 15;
  int priv = (m->_m_type & 128) ^ 128;

  if (type != PTHREAD_MUTEX_NORMAL) {
    self = __pthread_self();
    if ((m->_m_lock & 0x7fffffff) != self->tid)
      return EPERM;
    if ((type & 3) == PTHREAD_MUTEX_RECURSIVE && m->_m_count)
      return m->_m_count--, 0;
    if (!priv) {
      self->robust_list.pending = &m->_m_next;
      __vm_lock();
    }
    volatile void* prev = m->_m_prev;
    volatile void* next = m->_m_next;
    *(volatile void* volatile*)prev = next;
    if (next != &self->robust_list.head)
      *(volatile void* volatile*)((char*)next - sizeof(void*)) = prev;
  }
  cont = a_swap(&m->_m_lock, (type & 8) ? 0x40000000 : 0);
  if (type != PTHREAD_MUTEX_NORMAL && !priv) {
    self->robust_list.pending = 0;
    __vm_unlock();
  }
  if (waiters || cont < 0)
    __wake(&m->_m_lock, 1, priv);
  return 0;
}

weak_alias(__pthread_mutex_unlock, pthread_mutex_unlock);