process.py 文件源码

def Wait(self):
    # This is a list of async jobs
    try:
      pid, status = os.wait()
    except OSError as e:
      if e.errno == errno.ECHILD:
        #log('WAIT ECHILD')
        return False  # nothing to wait for caller should stop
      else:
        # What else can go wrong?
        raise

    #log('WAIT got %s %s', pid, status)

    # TODO: change status in more cases.
    if os.WIFSIGNALED(status):
      pass
    elif os.WIFEXITED(status):
      status = os.WEXITSTATUS(status)
      #log('exit status: %s', status)

    # This could happen via coding error.  But this may legitimately happen
    # if a grandchild outlives the child (its parent).  Then it is reparented
    # under this process, so we might receive notification of its exit, even
    # though we didn't start it.  We can't have any knowledge of such
    # processes, so print a warning.
    if pid not in self.callbacks:
      util.warn("PID %d stopped, but osh didn't start it", pid)
      return True  # caller should keep waiting

    callback = self.callbacks.pop(pid)
    callback(pid, status)
    self.last_status = status  # for wait -n

    return True  # caller should keep waiting