How to disable ctrl-alt-del and /etc/init/control-alt-del.conf in Linux?

Question

My OS is RHEL 6.2

I disable Ctrl+Alt+Del by changing in /etc/init/control-alt-del.conf the line

exec /sbin/shutdown -r now "Control-alt-del pressed"

by

exec /bin/true

I'll be testing it next Sunday.

My questions:

1. are there any daemons to restart?

2. I keep a copy on original /etc/init/control-alt-del.conf in /etc/init, is it safe?
   I mean won't the shutdown part of exec be fired?

3. more official way to disable Ctrl+Alt+Del?

---

edit:

tested on vmware player 6.0.3 (for what it is worth, this is not a virtualization issue)

1. editing file, no exec line, no restart, user logged on gui, send Ctrl+Alt+Del : shutdown prompt
2. after restart, no exec line, user logged on gui, send Ctrl+Alt+Del : shutdown prompt
3. after restart, exec /bin/true, user logged on gui, send Ctrl+Alt+Del : shutdown prompt
4. after restart, exec /bin/true, no user logged on gui, send Ctrl+Alt+Del : no shutdown prompt

Solution 1

change in /etc/init/control-alt-del.conf are taken immediatly.

I tested in ESX and physical hosts.

when I inserted

 exec date > /var/log/cad.log

in /etc/init/control-alt-del.conf

and issue Ctrl-AltDel I get date in /var/log/cad.log.

So no need to reboot.

Solution 2

Since this is the way to enable a function that acts on pressing Ctrl+Alt+Del, it is also the, probably official, point to switch if off.

You should just comment out ('#' in front of the line) the exec shutdown... and there is no need to insert exec /bin/true. No need to keep a copy of the file if you just comment things out.

I would reboot the system after the change, as I think it is init itself that reads that file, not some daemon. Just changing the file without further action doesn't have any effect¹.

¹ _{In the good old days you would set the Ctrl+Alt+Del handling in /etc/inittab and you could issue a init q after a change.}

Comments

[Admin]

Here is an init independent description of how the Linux kernel deals with Ctrl + Alt + Del: unix.stackexchange.com/questions/42573/…

[Арсений Черенков]

those are production system, I have no way to test it before a scheduled stop next sunday, when those will be reboted anyway.

[Anthon]

@Archemar After the reboot things should be ok.

[Gilles 'SO- stop being evil']

Why wouldn't one set the Ctrl+Alt+Del handling in /etc/inittab even today? RHEL 6.2 uses SysVinit.

[Timothy Martin]

@Gilles The /etc/inittab file is deprecated, and is now used only for setting up the default runlevel via the initdefault line. Other configuration is done via upstart jobs in the /etc/init directory. Copied from the Redhat Deployment site

[Stephen Gornick]

Answer "borrowed" from this response to a nearly identical question: askubuntu.com/questions/763887/…