pty/tty problem

[Bruno Wolff III]

I am trying to modify rlogin and rlogind to allow people to run a screen
oriented version of sas without logging in. We are running version 9.0
of convex unix on the rlogin machine. We want people to run sas on that
machine and have it look as though it is actually on that machine (there
isn't a version of sas for convex which is the root of the problem). The
other machine is going to be dedicated to running sas and is running ultrix
v4.1.
The problem is that the line that is opened is not being made to be the
control terminal. Sas works OK if it is told to use stdin and stdout,
but will not use its screen oriented format. When it trys to use the screen
oriented format it insists on using /dev/tty. But since there is no control
terminal this doesn't work.
According to the information I have found, just opening a terminal should
make it the control terminal (if you don't already have one and it isn't
being used by someone else). In trying to play around with the problem it
looks like the tty that is associated with the pty opened by the modified
rlogind program is not being treated as a terminal device.
I would appreciate any help on this problem.