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linuxhaskellroot

Checking root permissions from Haskell

My program requires elevated permissions and hence it crashes when run without these.

Is there a way of checking whether a Haskell program has been run as the root on Linux?

I.e., differentiating between

sudo ./myProgram

and

./myprogram
Solution

  • From the unix package, System.Posix.User:

    getRealUserID :: IO UserID
getEffectiveUserID :: IO UserID

    When run under sudo, I think they should both report 0 (root).

    When run as a setuid, only the second one should report 0 (if I remember correctly).

    The man pages for getuid / geteuid should clarify, I hope.