How to invoke root privileges from my custom app?

Question

In a GUI-environment, I want to be able to ask the user for the root/sudo password and then execute an app that requires root privileges from within my app.

As an example, say I want to run an editor to edit /etc/fstab, I need to start the editor via exec() or something with root privileges... how do I do this?

Note: gksu, gksudo is not an option - may not be available/installed

Answer 1

Method 1:

To run the "df -h" command as root:

su -c "df -h"

This will prompt the user for root password.

Method 2:

Alternatively, in /etc/sudoers find this line:

root ALL=(ALL) ALL

and duplicate it for your user johnsmith that you want to give admin privileges:

johnsmith ALL=(ALL) ALL

This way, johnsmith will be able to run any command requiring root rights, by first typing "sudo" in front of the command:

sudo df -h

Method 3:

You can use ssh to execute a command on the same machine:

ssh root@localhost "def -h"

will execute the same command in your server. If you don't want to be prompted for password, follow this tutorial for passwordless ssh:

http://linuxproblem.org/art_9.html

Method 4:

Use gksudo (graphical sudo):

gksudo "gnome-open %u"

Or, on KDE kdesu:

kdesu <command>