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From: dyer@spdcc.COM (Steve Dyer)
Newsgroups: comp.unix.xenix,comp.sources.wanted,comp.unix.questions
Subject: Re: tty watcher
Message-ID: <249@spdcc.COM>
Date: Thu, 10-Sep-87 14:54:06 EDT
Article-I.D.: spdcc.249
Posted: Thu Sep 10 14:54:06 1987
Date-Received: Sat, 12-Sep-87 09:33:04 EDT
References: <4263@ozdaltx.UUCP>
Reply-To: dyer@spdcc.COM (Steve Dyer)
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 19
Summary: talk is cheap, but
Xref: mnetor comp.unix.xenix:713 comp.sources.wanted:2191 comp.unix.questions:3988

It seems to me that you might be able to hack something up with a
new line discipline which paralleled the normal tty line discipline
with the exception that it replaced the l_input routine with one which,
before calling the standard l_input routine, enqueued its characters
on a private clist of a special device which could be read by the
'spy' program.

Another alternative is to take the public domain pty driver posted recently
and have your gettys running on the pty slaves instead of the serial lines
directly.  You would then have a 'telnetd'-like process reading and writing
to the pty controller and the serial device.  It could perform the logging
at that point in user mode.

None of these solutions are "free" without requiring some kernel work.
However, the pty solution is pretty simple to implement.
-- 
Steve Dyer
dyer@harvard.harvard.edu
dyer@spdcc.COM aka {ihnp4,harvard,linus,ima,bbn,m2c}!spdcc!dyer