Ultrix 4.1 TIOCSPGRP peculiarities -- is this correct behaviour?

[Ron Schnell]

This behavior is due to the POSIX session/pgrp requirements.  If I
remember correctly, the reason for the change was to fix the security
bug which allowed a user to set his terminal pgrp to something that
was unused at the moment, wait for someone else to login with that
pgrp, and then be able to send group signals by hitting control-c,
control-z, etc.

I may not have it right exactly.

#Ron
(ronnie at sos.com)