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Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!tgr!RSanders@DENVER.ARPA
From: RSanders@DENVER.ARPA
Newsgroups: net.sources
Subject: idle terminal killer - 4.2 BSD
Message-ID: <10092@brl-tgr.ARPA>
Date: Sun, 21-Apr-85 02:33:40 EST
Article-I.D.: brl-tgr.10092
Posted: Sun Apr 21 02:33:40 1985
Date-Received: Tue, 23-Apr-85 00:47:48 EST
Sender: news@brl-tgr.ARPA
Lines: 42

The following is a shell script/crontab line we've had running for more
than a year.  We have about 24 ports and about 100 terminals meeting at
a nicely wood-crafted plugboard, so contention is a problem.  Sorry, no
man page for this one - but carefully note the bug comment.
This works for us on VAX/4.2 BSD, and SUN 1/4.2 BSD.  Note that the
"echo -n" lines are supposed to have control-G's between the "".
I don't know if they will make it past various mailers.


-- Rex
.............................................................................
#! /bin/sh
# idlekill - kills idle logins
#   Rex Sanders, USGS Pacific Marine Geology, 4/24/84
#   modified 6/84 - CRONTAB warning, remove log - RS
#   modified 12/84 - use 'w' instead of 'wi' - RS
#   modified 4/85 - add lots more beeps to warning - RS
#
# BUG:  if a user is in a process for a long time that uses /dev/tty
#         directly (as in 'cc junk.c |& error -v'), 'w' reports idletime
#         incorrectly, and may unjustly kill a login.

# IDLEKILL is minutes of idle terminal before death eligibility
IDLEKILL=30
# CRONTAB is minutes between times idlekill is run by cron as in:
#  2,12,22,32,42,52 * * * * /etc/idlekill
CRONTAB=10
WARN=`expr $IDLEKILL - $CRONTAB`

for j in `/usr/ucb/w -h |   awk "{if (substr(\$0,27,2)*60+substr(\$0,30,2)+0 >= $IDLEKILL)     print \$2 }"`
do
  i=`expr $j : 'tty\(.*\)' '|' $j`
  echo "Your login is being killed for more than $IDLEKILL minutes of inactivity!" > /dev/$j
  echo `date` > /dev/$j
  kill -9 `ps -t${i} | awk '/ -.*sh /{print \$1}'`
done
for j in `/usr/ucb/w -h |   awk "{if (substr(\$0,27,2)*60+substr(\$0,30,2)+0 >= $WARN)     print \$2 }"`
do
  echo -n "" > /dev/$j
  echo "Your login will be killed in the next $CRONTAB minutes!" > /dev/$j
  echo -n "" > /dev/$j
done