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From: sef@kithrup.COM (Sean Eric Fagan)
Newsgroups: comp.std.unix
Subject: Re: disabling TIOCGPGRP on pty master sides
Message-ID: <15891@cs.utexas.edu>
Date: 14 Dec 90 19:52:18 GMT
References: <15827@cs.utexas.edu>
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Submitted-by: sef@kithrup.COM (Sean Eric Fagan)

In article <15827@cs.utexas.edu> nix%valis.asd.sgi.com@SGI.COM (Insufficient Dada) writes:
>This behavior breaks
>the subshell handling of GNU Emacs, and apparently interferes with the
>operation of the XView terminal emulator as well.  

First of all, emacs needs to do a setsid() in the sub-process; this makes
the pty it's controlling terminal (at least, this is how it works under
SCO's unix).

Second of all, because of the problem with tcgetpgrp() on another process'
pty, I added (for my own use) a new ioctl to the pty driver, called TIOCSIG
(as in, ioctl(fd, TIOCSIG, signo)), which sends an arbitray signal to the
process group on fd.  (Since I did it only for emacs, I didn't put in any
checks for security, although I plan on doing so eventually.)

I got this idea from a discussion with people at Berkeley.

-- 
Sean Eric Fagan  | "I made the universe, but please don't blame me for it;
sef@kithrup.COM  |  I had a bellyache at the time."
-----------------+           -- The Turtle (Stephen King, _It_)
Any opinions expressed are my own, and generally unpopular with others.

Volume-Number: Volume 22, Number 31