Console
Console Access
When normal (non-root) users log into a computer locally, they are given two types of special permissions:
- They can run certain programs that they would not otherwise be able to run
- They can access certain files (normally special device files used to access diskettes, CD-ROMs, and so on) that they would not otherwise be able to access
Since there are multiple consoles on a single computer and multiple users can be logged into the computer locally at the same time, one of the users has to "win" the race to access the files. The first user to log in at the console owns those files. Once the first user logs out, the next user who logs in will own the files.
In contrast, every user who logs in at the console will be allowed to run programs that accomplish tasks normally restricted to the root user. If X is running, these actions can be included as menu items in a graphical user interface. As shipped, the console-accessible programs include halt, poweroff, and reboot.
Disabling Shutdown Via Ctrl-Alt-Del
By default,
/etc/inittab specifies that your system
is set to shutdown and reboot the system in response to a
ca::ctrlaltdel:/sbin/shutdown -t3 -r now
Alternatively, you may just want to allow certain non-root users the
right to shutdown the system from the console using
- Add a
-a option to the
/etc/inittab line shown above, so that it
reads:
ca::ctrlaltdel:/sbin/shutdown -a -t3 -r now
The -a flag tells shutdown to look for the /etc/shutdown.allow file, which you will create in the next step.
- Create a file named
shutdown.allow in
/etc. The
shutdown.allow file should list the usernames
of any users who are allowed to shutdown the system using
[Ctrl] -[Alt] -[Del] . The format of the /etc/shutdown.allow file is a list of usernames, one per line, like the following:stephen jack sophie
According to this example
shutdown.allow file,
stephen, jack, and sophie are allowed to shutdown the
system from the console using
