74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
/*-
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* Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: realhostname.c,v 1.1 1999/04/06 23:02:35 brian Exp $
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <string.h>
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#include "libutil.h"
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int
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realhostname(char *host, size_t hsize, const struct in_addr *ip)
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{
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int result;
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struct hostent *hp;
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result = HOSTNAME_INVALIDADDR;
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hp = gethostbyaddr((char *)ip, sizeof(*ip), AF_INET);
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if (hp != NULL && strlen(hp->h_name) <= hsize) {
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char lookup[MAXHOSTNAMELEN];
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strncpy(lookup, hp->h_name, sizeof(lookup) - 1);
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lookup[sizeof(lookup) - 1] = '\0';
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hp = gethostbyname(lookup);
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if (hp == NULL)
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result = HOSTNAME_INVALIDNAME;
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else for (; ; hp->h_addr_list++) {
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if (hp->h_addr_list[0] == NULL) {
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result = HOSTNAME_INCORRECTNAME;
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break;
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}
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if (!memcmp(*hp->h_addr_list, ip, sizeof(*ip))) {
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strncpy(host, lookup, hsize);
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return HOSTNAME_FOUND;
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}
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}
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}
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strncpy(host, inet_ntoa(*ip), hsize);
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return result;
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}
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