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From: james@cantuar.UUCP (J. Collier)
Newsgroups: comp.unix.wizards
Subject: Re: Large machines and tty naming conventions.
Message-ID: <157@cantuar.UUCP>
Date: Thu, 13-Aug-87 00:41:32 EDT
Article-I.D.: cantuar.157
Posted: Thu Aug 13 00:41:32 1987
Date-Received: Sat, 15-Aug-87 17:17:07 EDT
References: <8550@brl-adm.ARPA> <7757@mimsy.UUCP>
Reply-To: james@cantuar.UUCP (J. Collier)
Organization: University of Canterbury, Christchurch, New Zealand
Lines: 22
Keywords: servers pty pseudo-terminals
Summary: pseudo-terminal server/library interface suggestion.

In article <7757@mimsy.UUCP> Chris Torek (chris@mimsy.UUCP) writes:
>                                          ......  Even so, finding a
>free pair of ptys is too hard; 4BSD needs a general resource manager,
>with which one can simply say `call this phone number' or `I want
>a pty master and slave' or `I would like to write to joe'.
>
   I have developed a pseudo-terminal server and a couple of client library
routines for handling the allocation of pseudo-terminals. The library routines
use unix-domain IPC to acquire and relinquish master/slave pairs from the server
 - the master fd is passed in the access rights field to avoid races. Since the 
server runs as root it can also handle tty ownership and utmp updating if 
requested. Client processes are periodically checked and privileges are revoked
if they have died.
   The system is somewhat hairy in places, especially in its attempts to provide
a reasonable level of security. This may not be justifiable, given that tty
security is still a bad joke anyway (4.3BSD). It also contains a certain amount
of borrowed code (utmp stuff & other bits from John Bruner's "uw").
   Perhaps someone would be interested in writing a similar system suitable for
public release.
-------------------------
James Collier  (james@cantuar.uucp / {watmath,munnari,mcvax}!cantuar!james)
Computer Science Dept., University of Canterbury, Christchurch, New Zealand.