Timed User Sessions

I did the following things to setup auto-logout/timed user-sessions for my son on our home computer running Linux (Ubuntu 11.04):

Edited the file “/etc/security/time.conf” and added the following line:
login|gdm;*;toby;MoTuWeThFr1700-2000|MoTuWeThFr0800-1500

This limits the user “toby” to login only on weekdays between the specified times.
Add the following line after the “auth” statements in the “/etc/pam.d/login” and “/etc/pam.d/gdm” files:
account required pam_time.so
Add the following lines to root’s crontab file (run “crontab -e” as the root user):
0 15 * * 1-5 /usr/bin/zenity –warning –text=’Logging Toby off in 5 minutes!’ –display=:0.0
5 15 * * 1-5 /usr/bin/killall -s KILL -u toby
0 20 * * 1-5 /usr/bin/zenity –warning –text=’Logging Toby off in 5 minutes!’ –display=:0.0
5 20 * * 1-5 /usr/bin/killall -s KILL -u toby

The zenity command is used to display a warning dialog in the Gnome session for the user “toby” five minutes before the killall command abruptly kills all running programs and the gnome session.
Add the following line to /etc/bash.bashrc:
xhost + >& /dev/null
This will allow the zenity command write to the user’s session (see crontab entries).