system.py 文件源码

def user(pid):
  """
  Provides the user a process is running under.

  :param int pid: process id of the process to be queried

  :returns: **str** with the username a process is running under, **None** if
    it can't be determined
  """

  if not isinstance(pid, int) or pid < 0:
    return None

  if stem.util.proc.is_available():
    try:
      import pwd  # only available on unix platforms

      uid = stem.util.proc.uid(pid)

      if uid and uid.isdigit():
        return pwd.getpwuid(int(uid)).pw_name
    except:
      pass

  if is_available('ps'):
    results = call('ps -o user %s' % pid, [])

    if len(results) >= 2:
      return results[1].strip()

  return None