# File lib_core/rucy/messenger.rb, line 374
    def open(server)
      @messenger_threads = server.messenger_threads
      @messenger_queue_length = server.messenger_queue_length
      @subprocess_user = server.subprocess_user
      @subprocess_group = server.subprocess_group

      @child_socket, @parent_socket = UNIXSocket.socketpair
      if (@pid = fork) then
        @child_socket.close
      else
        @parent_socket.close
        begin
          child_process
        rescue StandardError, ScriptError
          @logger.err("error: aborted child process: #{$!.message} (#{$!.class}): #{$!.backtrace[0]}")
        ensure
          exit!
        end
      end

      nil
    end