NetBSD/usr.sbin/ypserv/common/localhostname.c

91 lines
3.0 KiB
C

/* $NetBSD: localhostname.c,v 1.8 2002/07/06 21:39:25 wiz Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: localhostname.c,v 1.8 2002/07/06 21:39:25 wiz Exp $");
#endif
#include <sys/param.h>
#include <sys/socket.h>
#include <err.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "protos.h"
void
localhostname(char *buf, size_t buflen)
{
struct addrinfo *res, hints;
char hostname[MAXHOSTNAMELEN + 1];
int error;
if (gethostname(hostname, sizeof(hostname)))
err(1, "gethostname");
hostname[sizeof(hostname) - 1] = '\0';
memset(buf, 0, buflen);
/*
* If hostname appears to be fully-qualified,
* just return it.
*/
if (strchr(hostname, '.')) {
strlcpy(buf, hostname, buflen);
return;
}
/*
* Lookup the host. Return the canonical name.
*/
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_CANONNAME;
hints.ai_family = PF_UNSPEC;
error = getaddrinfo(hostname, NULL, &hints, &res);
if (error)
errx(1, "getaddrinfo(%s) failed: %s", hostname,
gai_strerror(error));
strlcpy(buf, res->ai_canonname, buflen);
freeaddrinfo(res);
}