code: public static function dirName($path = '/')
      {
          // 真实路径
          $path_runtime = realpath(RUNTIME_PATH);
          $path_list = dirname(realpath(RUNTIME_PATH . $path));
          
          // 上级路径
          if (strpos($path_list, $path_runtime) !== false) {
              return self::processDirName($path_list, $path_runtime);
          } else {
              return '/';
          }
      }
docs: 上级目录
  
  @param string $path
  @return string