I don't think it violates your tenet; leaving STDIN closed is really something you never want to do, and that's just what you are avoiding. However, (without having actually looked at it) I don't think the run harness should be closing STDIN when you pass it like that.

I don't think "<>" would work. Try "+<" or "+>".

I would do it as: open STDIN, "</dev/null" or die ... so perl's STDIN looks open as well as file descriptor 0.