Function auth_getitem 

pub unsafe extern "C" fn auth_getitem(
    _as: *mut auth_session_t,
    _item: c_uint,
) -> *mut c_char

Get the value of the item

From auth_subr(3):

The `item` may be one of:

AUTH_CHALLENGE      The latest challenge, if any, set for the session

AUTH_CLASS          The class of the user, as defined by the `/etc/login.conf` file. This 
                    value is not directly used by BSD Authentication, rather, it is passed
                    to the login scripts for their possible use.

AUTH_NAME           The name of the user being authenticated. The name should include the
                    instance, if any, that is being requested.

AUTH_SERVICE        The service requesting the authentication. Initially it is set to the
                    default service which provides the traditional interactive service.

AUTH_STYLE          The style of authentication being performed, as defined by the
                    `/etc/login.conf` file. The style determines which login script should
                    actually be used.

AUTH_INTERACTIVE    If set to any value, then the session is tagged as interactive. If not
                    set, the session is not interactive. When the value is requested it is
                    always either NULL or "True". The auth subroutines may choose to provide
                    additional information to standard output or standard error when the
                    session is interactive. There is no functional change in the operation
                    of the subroutines.