Ubuntu
cron package

Prevent user from shutting down?

Asked by tdn

I have a cron-job that is run daily on each laptop in the household. The cron job can sometimes take a while to complete (30 mins or so). The cron job is run as root.

How do I prevent users from shutting down the system, while the cron job is running? Actually I would like to prevent them from:
 * Logging out
 * Shut down
 * Reboot

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mycae (mycae) said : 		#1

http://www.addictivetips.com/ubuntu-linux-tips/add-restrictions-to-your-ubuntu-system-with-lockdown-editor-pessulus/

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tdn (spam-thomasdamgaard) said : 		#2

mycae: Thanks, but that does not solve my problem.
It seems that pessulus only removes some GUI elements from GNOME, is that correct?

Pessulus is a GUI tool. That does not help me much, since I must be able enable and disable logout/reboot from the cron-job.
I am imagining something like the following pseudo code for a crontab:
0 0 * * * root disable-logout && run-heavy-task && enable-logout

So, "disable-logout" changes the state of the system so that logout, reboot, shutdown, hibernate is disabled.
"run-heavy-task" is my script that takes a while to complete.
"enable-logout" reverts the changes that "disable-logout" made, thus enabling logout, reboot, shutdown and hibernate again.

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mycae (mycae) said : 		#3

>It seems that pessulus only removes some GUI elements from GNOME, is that correct?
Sounds about right, but I think you will find it is a fancy frontend to gconf2-tool. You can use this to do the same functionality as pessulus, by modifying the keys in gconf's database (/desktop/gnome/interface). THis can be done from the commandlines

But yes, it is just a hint -- a determined user can still log out. AFAIK, logging out is a user-level - you would need to prevent users from being allowed to terminate their processes, which is a bit weird.

Shutting down is of course a root level action, and could be more easily bulletproofed.

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