LOGIN_OK(3) BSD Library Functions Manual LOGIN_OK(3)NAME
auth_ttyok, auth_hostok, auth_timeok — functions for checking login class
based login restrictions
LIBRARY
System Utilities Library (libutil, -lutil)
SYNOPSIS
#include <sys/types.h>
#include <time.h>
#include <login_cap.h>
int
auth_ttyok(login_cap_t *lc, const char *tty);
int
auth_hostok(login_cap_t *lc, const char *host, char const *ip);
int
auth_timeok(login_cap_t *lc, time_t t);
DESCRIPTION
This set of functions checks to see if login is allowed based on login
class capability entries in the login database, login.conf(5).
auth_ttyok() checks to see if the named tty is available to users of a
specific class, and is either in the ttys.allow access list, and not in
the ttys.deny access list. An empty ttys.allow list (or if no such capa‐
bility exists for the give login class) logins via any tty device are
allowed unless the ttys.deny list exists and is non-empty, and the device
or its tty group (see ttys(5)) is not in the list. Access to ttys may be
allowed or restricted specifically by tty device name, a device name
which includes a wildcard (e.g. ttyD* or cuaD*), or may name a ttygroup,
when group=<name> tags have been assigned in /etc/ttys. Matching of ttys
and ttygroups is case sensitive. Passing a NULL or empty string as the
tty parameter causes the function to return a non-zero value.
auth_hostok() checks for any host restrictions for remote logins. The
function checks on both a host name and IP address (given in its text
form, typically n.n.n.n) against the host.allow and host.deny login class
capabilities. As with ttys and their groups, wildcards and character
classes may be used in the host allow and deny capability records. The
fnmatch(3) function is used for matching, and the matching on hostnames
is case insensitive. Note that this function expects that the hostname
is fully expanded (i.e. the local domain name added if necessary) and the
IP address is in its canonical form. No hostname or address lookups are
attempted.
It is possible to call this function with either the hostname or the IP
address missing (i.e. NULL) and matching will be performed only on the
basis of the parameter given. Passing NULL or empty strings in both
parameters will result in a non-zero return value.
The auth_timeok() function checks to see that a given time value is
within the times.allow login class capability and not within the
times.deny access lists. An empty or non-existent times.allow list
allows access at any time, except if a given time is falls within a
period in the times.deny list. The format of time period records con‐
tained in both times.allow and times.deny capability fields is explained
in detail in the login_times(3) manual page.
RETURN VALUES
A non-zero return value from any of these functions indicates that login
access is granted. A zero return value means either that the item being
tested is not in the allow access list, or is within the deny access
list.
SEE ALSOgetcap(3), login_cap(3), login_class(3), login_times(3), login.conf(5),
termcap(5)BSD January 2, 1997 BSD