Okay. I'm planning on setting up my now soon-to-be webserver to offer shell accounts under ssh. On logon it would greet the user, and tell him to logon as newuser or adduser or the like. Then it would throw him into creating a new user, but not with 'adduser' (since the user could easily just set the UID to 0, heh easiest root ever).
My friend told me to write a secure adduser program in C, only accepting the username and password as input from the user (the rest would be hardcoded into it).
But, C is not exactly my forte. I mean I could probably manage to do it, but it would take me a month or two to learn everything required. I've looked around, but to no avail.
Does anyone know of a way I could go about this easily? If not, any C programming guides that act around this (e.g. not general Learn C now! guides) will do fine.