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

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/* $NetBSD: localhostname.c,v 1.6 1998/07/06 07:06:39 mrg 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 1.6 1998/07/06 07:06:39 mrg Exp $");
#endif
#include <sys/param.h>
#include <err.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "protos.h"
void
localhostname(buf, buflen)
char *buf;
size_t buflen;
{
struct hostent *hp;
char hostname[MAXHOSTNAMELEN + 1];
int i;
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, '.')) {
snprintf(buf, buflen, "%s", hostname);
return;
}
/*
* Lookup the host. Return the first name that appears
* to be fully-qualified.
*/
hp = gethostbyname(hostname);
if (hp == NULL)
errx(1, "gethostbyname(%s) failed", hostname);
if (strchr(hp->h_name, '.')) {
snprintf(buf, buflen, "%s", hp->h_name);
return;
}
if (hp->h_aliases != NULL && hp->h_aliases[0] != NULL) {
for (i = 0; hp->h_aliases[i] != NULL; i++) {
if (strchr(hp->h_aliases[i], '.')) {
snprintf(buf, buflen, "%s", hp->h_aliases[i]);
return;
}
}
}
/*
* As a last resort, just return hostname.
*/
snprintf(buf, buflen, "%s", hostname);
}