I'm trying to lock some settings in order to run "kiosk" systems with Ubuntu 12.04, and it's getting me mad.
The main purpose is to prevent screen locking, hibernation and user-switching. Being able to restore usual shortcuts (Ctrl-Alt-Backspace to kill the X session, mostly) and make them mandatory for all users would be great too.
I've tried to do that both with xfce (after installing xubuntu-desktop) and Gnome Classic.
I've tried to use the settings editor to change shortcuts, but the "locked" checkbox doesn't seem to be checkable, even when the editor is launched with gksudo. So I have edited:
to get something like:
The result is that the property is indeed locked for normal users, but still set to xflock4. I have yet to find the entries for hibernation and others, but if this one already doesn't work properly...
<property name="<Primary><Alt>Delete" type=string" unlocked="rootlocal" value="xfce4-session-logout"/>
I have found a nice workaround for screen-locking, though:
That way, only admins can lock the system. Xfce doesn't seem to offer user-switching, which is perfect as far as I'm concerned.
chown rootlocal.admins /usr/bin/xflock4
chmod 770 /usr/bin/xflock4
So, I'm left with the issues of hibernation and suspend. There is also the Ctrl-Alt-Backspace shortcut.
I've tried just what I did before (Ubuntu 10.04): setting mandatory options through gconf-editor. It still appears to write them properly in:
Unfortunately, this does not seem to have any impact on users, who can still lock things, freeze things, and otherwise wreak havoc as they see fit.
I've not tried to set mandatory shortcuts with gnome-classic yet, but I've tried to do it through Unity's GUI some time ago, and it did not seem to work.
I would be very grateful if anyone here could hint me in the right direction, because I admit I'm about to bang my head over the wall (and possibly naughty users, too ).