Suggestions for objective-c to login via code into mac osx

I need to enhance a daemon (running as root) on macOSx in such a way that if client sends username and password over socket to daemon then it makes that user to log in, who is currently logged out not locked

I searched and found that if machine is locked it can be opened (ie knock to unlock, NameAndPassword) but could not search for logout user

is it possible??