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Path: utzoo!watmath!clyde!rutgers!ames!oliveb!sun!gorodish!guy
From: guy@gorodish.UUCP
Newsgroups: comp.bugs.sys5
Subject: Re: no nohup for rlogin/telnet
Message-ID: <12212@sun.uucp>
Date: Tue, 27-Jan-87 23:56:10 EST
Article-I.D.: sun.12212
Posted: Tue Jan 27 23:56:10 1987
Date-Received: Thu, 29-Jan-87 03:51:01 EST
References: <1985@emory.UUCP>
Sender: news@sun.uucp
Reply-To: guy@sun.UUCP (Guy Harris)
Organization: Sun Microsystems, Mountain View
Lines: 28
Keywords: rlogin telnet tcp/ip

>I am running WIN3B the TCP/IP package for the 3B2
>on System V Rel 2.0.5 (swapping). I just noticed that
>nohup does not prtotect background processes started from an
>rlogin or telnet session from termination at hangup.
>In fact even when I arrange to have ALL signals ignored by
>the process, it still terminates on disconnect.

It's amusing to see evidence that this package is, indeed, probably
based on the 4.2BSD code; unfortunately, this confirmation takes the
form of the appearance of a really stupid misfeature.

The 4.2BSD "telnetd" and "rlogind", for no apparent reason, insist on
sending a SIGKILL to the entire session when you log out.  You can't
arrange to have all signals ignored by the process; the system won't
let you ignore SIGKILL.

>Can anyone suggest another work around?

You might try writing a little wrapper program that does a "setpgrp"
and then runs a shell or something, and use this to kick off your
background jobs.  The SIGKILL is sent to the process group that the
session belongs to; the "setpgrp" will detach the process from that
process group, and thus keep the SIGKILL from hitting it or its
descendants (which will be in the same process group, unless they
subsequently change their process group).

This particular botch is "fixed in 4.3"; presumably, the Woolongong
Group will be picking up the 4.3BSD networking stuff at some point.