HOSTS_ACCESS(3)

NAME
hosts_access, hosts_ctl - access control library

SYNOPSIS
#include "log_tcp.h"
extern int allow_severity;
extern int deny_severity;
int hosts_access(daemon, client)
char *daemon;
struct client_info *client;
int hosts_ctl(daemon, client_name, client_addr, client_user)
char *daemon;
char *client_name;
char *client_addr;
char *client_user;

DESCRIPTION
The routines described in this document are part of the libwrap.a library. They implement a pattern-based access control language with optional shell commands that are executed when a pattern fires.

In all cases, the daemon argument should specify a daemon process name (argv[0] value). The client host address should be a valid address, or FROM_UNKNOWN if address lookup failed. The client host name and user name should be empty strings if no information is available, FROM_UNKNOWN if lookup failed, or an actual host or user name.

hosts_access() consults the access control tables described in the hosts_access(5) manual page. hosts_access() returns zero if access should be denied.

hosts_ctl() is a wrapper around the hosts_access() routine with a perhaps more convenient interface (though it does not pass on enough information to support automated remote username lookups). hosts_ctl() returns zero if access should be denied.

The allow_severity and deny_severity variables determine how accepted and rejected requests may be logged. They must be provided by the caller and may be modified by rules in the access control tables.

DIAGNOSTICS
Problems are reported via the syslog daemon.

SEE ALSO
hosts_access(5), format of the access control tables. hosts_options(5), optional extensions to the base language.

FILES
/etc/hosts.access, /etc/hosts.deny, access control tables.

BUGS
The functions described here do not make copies of their string-valued arguments. Beware of data from functions that overwrite their results upon each call.

hosts_access() uses the strtok() library function. This may interfere with other code that relies on strtok().

AUTHOR
Wietse Venema (wietse@wzv.win.tue.nl)
Department of Mathematics and Computing Science
Eindhoven University of Technology
Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands