Disable reboot when ctrl-alt-del is pressed

This document (7023999) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12 
SUSE Linux Enterprise Desktop 12 
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15

Situation

When using a tty console, by default pressing ctrl alt del ( ctrl-alt-del )  will reboot the system. In some situations, this behavior may need to be disabled.
 
In a tty, the ctrl-alt-delete.target is a symlink to reboot.target:
SUSE:/home/SUSE/ # ls -lah /usr/lib/systemd/system/ctrl-alt-del.target
lrwxrwxrwx 1 root root 13 Jul 11 09:12 /usr/lib/systemd/system/ctrl-alt-del.target -> reboot.target

In gnome, we see that ctrl-alt-delete points to a logout plugin:
SUSE:/home/SUSE/ # gsettings list-recursively org.gnome.settings-daemon.plugins.media-keys org.gnome.settings-daemon.plugins.media-keys logout '<Control><Alt>Delete'

Resolution

To change the reboot behavior to no longer reboot in a tty on ctrl-alt-del, point the symlink to /dev/null instead and the key combination will no longer reboot the system:

ln -sf /dev/null /usr/lib/systemd/system/ctrl-alt-del.target

 

Now check to ensure the symlink has been updated as expected:

SUSE:/home/SUSE/ #  ls -lah /usr/lib/systemd/system/ctrl-alt-del.target
lrwxrwxrwx 1 root root 9 Jul 11 09:23 /usr/lib/systemd/system/ctrl-alt-del.target -> /dev/null
You have new mail in /var/spool/mail/logan

 

Ctrl-alt-del reboot has now been disabled. Test ctrl-alt-del to verify.

 

To change this behavior to no longer reboot in gnome on ctrl-alt-del, change the value for the logout key to something else. In the following example, it will be changed to ctrl-alt-shift-del requiring shift to be pressed as well.

Run the following logged into gnome for the user you wish to change:

gsettings set org.gnome.settings-daemon.plugins.media-keys logout '<Control><Alt><Shift>Delete'


Now test ctrl-alt-del.
This will need to be run for each existing or new user which you wish to change the ctrl-alt-del behavior for.
This is not ideal, as a disadvantage of this is that this can be overwritten by the user too..)

When it is desirable to disable the ctrl-alt-del behavior globally and for all users, follow the following procedure :

Create /etc/dconf/profile/user  file with the following content :

user-db:user
system-db:local


Create /etc/dconf/db/local.d/01-local  file with the following content :

[org/gnome/settings-daemon/plugins/media-keys]
logout='<Control><Alt><Shift>Delete'


Lock the logout property by creating /etc/dconf/db/local.d/locks/media-keys  file with the following content :

/org/gnome/settings-daemon/plugins/media-keys/logout

Next save and update the dconf database :

dconf update

 


 

Cause

Once SLES or SLED has booted to a tty (not graphical.target), ctrl-alt-delete is controlled by systemd from a text console. By default, we see that the ctrl-alt-delete.target is a symlink to reboot.target. 
 
Gnome (or SLE-Classic) uses hotkeys to reboot with the logout gnome plugin. By default, it is ctrl-alt-del.

Additional Information

There may also be a desire to create Global Custom keybindings for shutdown.
This procedure has been detailed in TID 000019048 - Define global customer keybindings for shutdown

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7023999
  • Creation Date: 11-Jul-2019
  • Modified Date:11-Feb-2021
    • SUSE Linux Enterprise Desktop
    • SUSE Linux Enterprise Server

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