Programmatically getting UID and GID from username in Unix?

Question

I\'m trying to use setuid() and setgid() to set the respective id\'s of a program to drop privileges down from root, but to use them I need to know the uid and gid of the us

Answer 1

You want to use the getpw* family of system calls, generally in pwd.h. It's essentially a C-level interface to the information in /etc/passwd.