News Group Posts

preventing use of specific tty

ports

From: Bela Lubkin <belal@sco.com>
Subject: Re: busying out a pseudo tty
Date: 2 Oct 2003 17:31:04 -0400
References: <c5a0626d.0310021152.1e7ec391@posting.google.com> 

PW Herman wrote:

> Hi, I've got a weird problem with an old un-supported dentist program
> that runs on Openserver 5.0.4.  For some reason, it gives error
> messages in certain menus if the user logs in on ttyp2, ttyp3, ttyp4
> or ttyp5.  Is there any way to make these 4 pseudo ttys appear to be
> busy so nobody ever connects on them???

If you open the master sides (/dev/ptyp2 etc.), they will be busied out.
You can do that with a very simple shell script that you could e.g. run
as an rc script.  For example,

  #!/bin/sh

  # Busy out ports ttyp2, 3, 4, 5 because "un-supported dentist program"
  # is allergic to them...

  sleep 1000000000 < /dev/ptyp2 &
  sleep 1000000000 < /dev/ptyp3 &
  sleep 1000000000 < /dev/ptyp4 &
  sleep 1000000000 < /dev/ptyp5 &

Save as /etc/rc2.d/S99pty-hold or something like that.

You can save a few processes if you wish (but this gets messy if you
want to busy out dozens of ports):

  cd /dev
  sleep 1000000000 2<ptyp2 3<ptyp3 4<ptyp4 5<ptyp5 &
  # Note that shell syntax allows redirecting fd's 0-9, no higher: 10<
  # does not work.

>Bela<

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