But where does system() come in to play then? If you're not dealing with privileged/setuid programs, then a program which calls system() isn't doing anything th

But where does system() come in to play then? If you're not dealing with privileged/setuid programs, then a program which calls system() isn't doing anything that you couldn't do yourself. A well crafted sudoers file can help control what gets run with sudo, but that happens regardless of how sudo is invoked.