sfork

# File lib/shell/process-controller.rb, line 194
    def sfork(command, &block)
      pipe_me_in, pipe_peer_out = IO.pipe
      pipe_peer_in, pipe_me_out = IO.pipe
      Thread.critical = true

      STDOUT.flush
      ProcessController.each_active_object do |pc|
        for jobs in pc.active_jobs
          jobs.flush
        end
      end
      
      pid = fork {
        Thread.critical = true

        Thread.list.each do |th| 
          th.kill unless [Thread.main, Thread.current].include?(th)
        end

        STDIN.reopen(pipe_peer_in)
        STDOUT.reopen(pipe_peer_out)

        ObjectSpace.each_object(IO) do |io| 
          if ![STDIN, STDOUT, STDERR].include?(io)
            io.close unless io.closed?
          end
        end
        yield
      }

      pipe_peer_in.close
      pipe_peer_out.close
      command.notify "job(%name:##{pid}) start", @shell.debug?
      Thread.critical = false

      th = Thread.start {
        Thread.critical = true
        begin
          _pid = nil
          command.notify("job(%id) start to waiting finish.", @shell.debug?)
          Thread.critical = false
          _pid = Process.waitpid(pid, nil)
        rescue Errno::ECHILD
          command.notify "warn: job(%id) was done already waitipd."
          _pid = true
        ensure
          # when the process ends, wait until the command termintes
          if _pid
          else
            command.notify("notice: Process finishing...",
                           "wait for Job[%id] to finish.",
                           "You can use Shell#transact or Shell#check_point for more safe execution.")
            redo
          end
          Thread.exclusive do
            @job_monitor.synchronize do 
              terminate_job(command)
              @job_condition.signal
              command.notify "job(%id) finish.", @shell.debug?
            end
          end
        end
      }
      return pid, pipe_me_in, pipe_me_out
    end