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From: mwm@eris.BERKELEY.EDU (Mike (My watch has windows) Meyer)
Newsgroups: comp.unix.xenix,comp.sources.wanted,comp.unix.questions
Subject: Re: tty watcher
Message-ID: <5070@jade.BERKELEY.EDU>
Date: Fri, 11-Sep-87 18:21:20 EDT
Article-I.D.: jade.5070
Posted: Fri Sep 11 18:21:20 1987
Date-Received: Sat, 12-Sep-87 20:08:18 EDT
References: <4263@ozdaltx.UUCP>
Sender: usenet@jade.BERKELEY.EDU
Reply-To: mwm@eris.BERKELEY.EDU (Mike (My watch has windows) Meyer)
Organization: Missionaria Phonibalonica
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Xref: mnetor comp.unix.xenix:724 comp.sources.wanted:2210 comp.unix.questions:4015

In article <4263@ozdaltx.UUCP> root@ozdaltx.UUCP (root) writes:
<A while back I'd asked if anyone has an effective tty
<watcher or "spy" program, or if they had suggestion as to
<how such a thing could be accomplished.

Must have missed it; or ignored it assuming that somone more
knowledgeable than I would answer.

<Several versions of *NIX must have had a "hook" or stub in
<the kernal as more than one person made mention of a 'spy'
<program that effectivally let you tune in on some one elses
<tty.

Don't recall having seen them, but can easily believe it. But there's
a better way.

<To make a long story short, appearently it just can't be
<done.

It can be done. The trick is to wade through the kernel data
structures in /dev/kmem until you find where incoming characters from
that tty are being stored, and then watch that space. A program to do
this on 4BSD made the rounds about 3 years ago, causing a flurry

	chmod 540 /dev/*mem* /vmunix
	chgrp kmem /dev/*mem* /vmunix /bin/ps <and similar things>
	chmod 2711 /bin/ps <and similar things>

commands to be issued

<Looks like MS-DOS wins this round.

When did MS-DOS start supporting multiple users so that such a thing
would make sense?

	<mike
--
When logic and proportion have fallen soggy dead,	Mike Meyer
And the white knight is talking backwards,		mwm@berkeley.edu
And the red queen's on her head,			ucbvax!mwm
Remember what the dormouse said.			mwm@ucbjade.BITNET