in reply to dropping from root to lower user

although you can (as per the other answers), you realy shouldn't be running a process as root in the first instance. Try realy hard to avoid running the prog as root in the first place, unless this program will never live on a machine that ever gets connected to the internet. if you realy must run it as root (which is not the case in 99.99% of situations) then make sure any input is squeaky clean with taint etc.