What is the best way for checking if the user of a script has root-like privileges?

Question

I have a Python script that will be doing a lot of things that would require root-level privileges, such as moving files in /etc, installing with apt-get, and so on. I currently have:

if os.geteuid() != 0:     exit("You need to have root privileges to run this script.\nPlease try again, this time using 'sudo'. Exiting.") 

Is this the best way to do the check? Are there other best practices?

Answer 1

os.geteuid gets the effective user id, which is exactly what you want, so I can't think of any better way to perform such a check. The one bit that's uncertain is that "root-like' in the title: your code checks for exactly root, no "like" about it, and indeed I wouldn't know what "root-like but not root" would mean -- so, if you mean something different than "exactly root", perhaps you can clarify, thanks!

Answer 2

Under the "Easier to Ask Forgiveness than Permission" principle:

try:     os.rename('/etc/foo', '/etc/bar') except IOError as e:     if (e[0] == errno.EPERM):        sys.exit("You need root permissions to do this, laterz!") 

If you are concerned about the non-portability of os.geteuid() you probably shouldn't be mucking with /etc anyway.