auth_ttyok(3) on FreeBSD
The text e41dd42a6607, as FreeBSD 3.2-RELEASE, FreeBSD 3.1-RELEASE, FreeBSD 3.0-RELEASE, FreeBSD 2.2.8-RELEASE, FreeBSD 2.2.7-RELEASE, FreeBSD 2.2.6-RELEASE, FreeBSD 2.2.5-RELEASE, FreeBSD 2.2.2-RELEASE shipped it.
Functions for checking login class based login restrictions