# File lib_core/rucy/rc_d.rb, line 80
    def lock
      begin
        @File.open(@lock, File::WRONLY | File::CREAT | File::TRUNC | File::EXCL) {|output|
          output.write($$.to_s + "\n")
        }
      rescue Errno::EEXIST
        pid = read_pid
        if (@ProcessProbe.proc_alive? pid) then
          raise 'running server'
        else
          # race condition (^_^;)
          # don't parallel lock!
          @File.delete(@lock)
          retry
        end
      end

      nil
    end