It's possible to get root privileges by simple code like this:

but this solution requires to set sticky bit chown root:root; chmod u+s.

The question is how to get root privileges only by providing user name and password (by process and to this process, - so process asking user for login information and use this permission to execution).

Solution shall work on all of the modern Linux environments since RHEL 4.

Root privileges to run/execute what?

This is not sticky bit. But this is changing owner/group to root:root and then applying SUID. Sticky bit can be set as:-
But once let's know what is your purpose of doing this, and where you want to apply these changes?

It's easier to just set the command-prompt to "#" from "$".

Believe me, kid, if it really were this easy, legions of bored MIT students would have done it long before you were born.

I am working on GUI program that should ask user for in which mode this program should be executed, under non-root account (under is user account) or under privileged account (under root). So, I just have a dialog with that options, and if users clicked to continue execution under root account, program asks user for login information.

I know some tricks with IOCTL, but I think it's not good idea to going around su command. In addition, this program should be transferred without installation and I can't ask user to set file system permissions before launch.

Thank you for your opinion, but if there is no easiest ways are exists, can you suggest a hard one? This feature is really necessary for my app, and I have to find a solution.

Once share the screenshot of the error dialogue box. And let's know what is your application.

However, if you've to set sticky bit, you can use above said method. It's actually used to run an executable with file owner's privileges and in your case it's root. So when you will invoke the excutable file (i.e. your application), you will automatically invoke it with root privilages.

So once also share output of following:-

On RHEL there is a preferred method for doing that which involves using consolehelper. I suggest you use that instead of re-inventing the wheel yourself or introducing setuid root binaries completely unnecessarily.

I am workin on application installer that should ask user in which privileges installer should install an apps, for current user, or for all users. So, I can ask user about setting file system permission.

Error box? I don't have any error messages, and ls will show you usual permissions.

Thank you unSpawn, unfortunately for this solution, app should work on any modern Linux distributions, not only RHEL.

You want to use kdesudo, gksu or something similar.

AFAIK Gnomesu, gksudo, gksu, kdesu, kdesudo are tied to the installed choice of Desktop Environments. consolehelper OTOH is tied to PAM so most current, maintained distro releases should have it.

Sure, but am I looking for how to do this by system calls. And from your suggestion, PAM is available since RHEL 5, for me RHEL 4 support is also required.

I agree, this solution will work on most of the system now, but what happened one day, when new desktop environment will be released and user will try to this this app? No *su* will be found, and application functionality will be missed. It's not a right way to solve this puzzle. It's also affects user who will try to start an app in very unusual DE.

Previous millennium. Old school. PAM was already incorporated way back when Fedora's predecessor still went by the name of "Red Hat Linux".

Ok, only one way to use PAM what I found (http://vkrejcirik.info/2012/06/09/au...-pam-in-linux/) is to change group permissions. But, I need a way where I do not need to change anything on a user machine, just ask for user name and password and do my job.