.\" Copyright (c) 2003 - 2005 Kungliga Tekniska Högskolan
.\" (Royal Institute of Technology, Stockholm, Sweden).
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" 3. Neither the name of the Institute nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $Id$
.\"
.Dd April 24, 2005
.Dt KRB5_SET_DEFAULT_REALM 3
.Os HEIMDAL
.Sh NAME
.Nm krb5_copy_host_realm ,
.Nm krb5_free_host_realm ,
.Nm krb5_get_default_realm ,
.Nm krb5_get_default_realms ,
.Nm krb5_get_host_realm ,
.Nm krb5_set_default_realm
.Nd default and host realm read and manipulation routines
.Sh LIBRARY
Kerberos 5 Library (libkrb5, -lkrb5)
.Sh SYNOPSIS
.In krb5.h
.Ft krb5_error_code
.Fo krb5_copy_host_realm
.Fa "krb5_context context"
.Fa "const krb5_realm *from"
.Fa "krb5_realm **to"
.Fc
.Ft krb5_error_code
.Fo krb5_free_host_realm
.Fa "krb5_context context"
.Fa "krb5_realm *realmlist"
.Fc
.Ft krb5_error_code
.Fo krb5_get_default_realm
.Fa "krb5_context context"
.Fa "krb5_realm *realm"
.Fc
.Ft krb5_error_code
.Fo krb5_get_default_realms
.Fa "krb5_context context"
.Fa "krb5_realm **realm"
.Fc
.Ft krb5_error_code
.Fo krb5_get_host_realm
.Fa "krb5_context context"
.Fa "const char *host"
.Fa "krb5_realm **realms"
.Fc
.Ft krb5_error_code
.Fo krb5_set_default_realm
.Fa "krb5_context context"
.Fa "const char *realm"
.Fc
.Sh DESCRIPTION
.Fn krb5_copy_host_realm
copies the list of realms from
.Fa from
to
.Fa to .
.Fa to
should be freed by the caller using
.Fa krb5_free_host_realm .
.Pp
.Fn krb5_free_host_realm
frees all memory allocated by
.Fa realmlist .
.Pp
.Fn krb5_get_default_realm
returns the first default realm for this host.
The realm returned should be freed with
.Fn free .
.Pp
.Fn krb5_get_default_realms
returns a
.Dv NULL
terminated list of default realms for this context.
Realms returned by
.Fn krb5_get_default_realms
should be freed with
.Fn krb5_free_host_realm .
.Pp
.Fn krb5_get_host_realm
returns a
.Dv NULL
terminated list of realms for
.Fa host
by looking up the information in the
.Li [domain_realm]
in
.Pa krb5.conf
or in
.Li DNS .
If the mapping in
.Li [domain_realm]
results in the string
.Li dns_locate ,
DNS is used to lookup the realm.
.Pp
When using
.Li DNS
to a resolve the domain for the host a.b.c,
.Fn krb5_get_host_realm
looks for a
.Dv TXT
resource record named
.Li _kerberos.a.b.c ,
and if not found, it strips off the first component and tries a again
(_kerberos.b.c) until it reaches the root.
.Pp
If there is no configuration or DNS information found,
.Fn krb5_get_host_realm
assumes it can use the domain part of the
.Fa host
to form a realm.
Caller must free
.Fa realmlist
with
.Fn krb5_free_host_realm .
.Pp
.Fn krb5_set_default_realm
sets the default realm for the
.Fa context .
If
.Dv NULL
is used as a
.Fa realm ,
the
.Li [libdefaults]default_realm
stanza in
.Pa krb5.conf
is used.
If there is no such stanza in the configuration file, the
.Fn krb5_get_host_realm
function is used to form a default realm.
.Sh SEE ALSO
.Xr free 3 ,
.Xr krb5.conf 5