Convenience. You could parse the input by hand, or you can use the auth functions which do fairly paranoid input validation, logging, and such for you.
And this section here seems to do auth by again calling a helper binary. Which if I’m reading it right ends up being one of the login binaries listening on fd3.
There is something I don’t understand.
To make a module, you just pop an executable in the right place ready to chat over fd3.
So why and when would you need the various other functions from the bsd auth library?
Convenience. You could parse the input by hand, or you can use the auth functions which do fairly paranoid input validation, logging, and such for you.
Here’s the helper code: https://github.com/openbsd/src/blob/master/lib/libc/gen/authenticate.c
https://github.com/openbsd/src/blob/master/lib/libc/gen/authenticate.c#L536
And this section here seems to do auth by again calling a helper binary. Which if I’m reading it right ends up being one of the login binaries listening on fd3.