279 lines
7.0 KiB
C
279 lines
7.0 KiB
C
/* $NetBSD: gethost.c,v 1.8 2003/08/07 09:27:57 agc Exp $ */
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/*-
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* Copyright (c) 1985, 1988, 1993
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* The Regents of the University of California. 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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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* -
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* --Copyright--
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*/
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/*
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* Copied from: lib/libc/net/gethostnamadr.c
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* and then gutted, leaving only /etc/hosts support.
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*/
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#include <sys/cdefs.h>
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#ifdef __weak_alias
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#define gethostbyaddr _gethostbyaddr
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#define gethostbyname _gethostbyname
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#endif
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <netdb.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <errno.h>
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#include <string.h>
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#ifdef __weak_alias
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__weak_alias(gethostbyaddr,_gethostbyaddr);
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__weak_alias(gethostbyname,_gethostbyname);
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#endif
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#define MAXALIASES 35
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#define MAXADDRS 35
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static char *h_addr_ptrs[MAXADDRS + 1];
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static struct hostent host;
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static char *host_aliases[MAXALIASES];
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static char hostbuf[BUFSIZ+1];
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static struct in_addr host_addr;
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static FILE *hostf = NULL;
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static int stayopen = 0;
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void _sethtent __P((int));
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void _endhtent __P((void));
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struct hostent *_gethtent __P((void));
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struct hostent *_gethtbyname __P((const char *));
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struct hostent *_gethtbyaddr __P((const char *, int, int));
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#if PACKETSZ > 1024
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#define MAXPACKET PACKETSZ
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#else
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#define MAXPACKET 1024
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#endif
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extern int h_errno;
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struct hostent *
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gethostbyname(name)
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const char *name;
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{
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register const char *cp;
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/*
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* disallow names consisting only of digits/dots, unless
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* they end in a dot.
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*/
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if (isdigit(name[0]))
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for (cp = name;; ++cp) {
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if (!*cp) {
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if (*--cp == '.')
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break;
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/*
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* All-numeric, no dot at the end.
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* Fake up a hostent as if we'd actually
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* done a lookup.
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*/
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if (!inet_aton(name, &host_addr)) {
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h_errno = HOST_NOT_FOUND;
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return((struct hostent *) NULL);
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}
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host.h_name = (char *)name;
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host.h_aliases = host_aliases;
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host_aliases[0] = NULL;
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host.h_addrtype = AF_INET;
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host.h_length = sizeof(u_int32_t);
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = NULL;
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host.h_addr_list = h_addr_ptrs;
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return (&host);
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}
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if (!isdigit(*cp) && *cp != '.')
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break;
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}
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/* XXX - Force host table lookup. */
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return (_gethtbyname(name));
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}
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struct hostent *
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gethostbyaddr(addr, len, type)
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const char *addr;
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socklen_t len;
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int type;
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{
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char qbuf[MAXDNAME];
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if (type != AF_INET)
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return ((struct hostent *) NULL);
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(void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
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((unsigned)addr[3] & 0xff),
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((unsigned)addr[2] & 0xff),
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((unsigned)addr[1] & 0xff),
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((unsigned)addr[0] & 0xff));
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/* XXX - Force host table lookup. */
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return (_gethtbyaddr(addr, len, type));
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}
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void
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_sethtent(f)
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int f;
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{
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if (hostf == NULL)
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hostf = fopen(_PATH_HOSTS, "r" );
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else
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rewind(hostf);
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stayopen = f;
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}
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void
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_endhtent()
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{
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if (hostf && !stayopen) {
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(void) fclose(hostf);
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hostf = NULL;
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}
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}
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struct hostent *
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_gethtent()
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{
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char *p;
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register char *cp, **q;
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if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
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return (NULL);
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again:
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if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
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return (NULL);
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if (*p == '#')
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goto again;
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cp = strpbrk(p, "#\n");
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if (cp == NULL)
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goto again;
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*cp = '\0';
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cp = strpbrk(p, " \t");
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if (cp == NULL)
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goto again;
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*cp++ = '\0';
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/* THIS STUFF IS INTERNET SPECIFIC */
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = NULL;
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(void) inet_aton(p, &host_addr);
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host.h_addr_list = h_addr_ptrs;
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host.h_length = sizeof(u_int32_t);
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host.h_addrtype = AF_INET;
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while (*cp == ' ' || *cp == '\t')
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cp++;
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host.h_name = cp;
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q = host.h_aliases = host_aliases;
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cp = strpbrk(cp, " \t");
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if (cp != NULL)
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*cp++ = '\0';
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while (cp && *cp) {
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if (*cp == ' ' || *cp == '\t') {
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cp++;
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continue;
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}
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if (q < &host_aliases[MAXALIASES - 1])
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*q++ = cp;
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cp = strpbrk(cp, " \t");
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if (cp != NULL)
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*cp++ = '\0';
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}
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*q = NULL;
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return (&host);
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}
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struct hostent *
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_gethtbyname(name)
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const char *name;
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{
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register struct hostent *p;
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register char **cp;
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_sethtent(0);
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while ((p = _gethtent()) != NULL) {
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if (strcasecmp(p->h_name, name) == 0)
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break;
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for (cp = p->h_aliases; *cp != 0; cp++)
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if (strcasecmp(*cp, name) == 0)
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goto found;
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}
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found:
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_endhtent();
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if (p==NULL)
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h_errno = HOST_NOT_FOUND;
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return (p);
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}
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struct hostent *
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_gethtbyaddr(addr, len, type)
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const char *addr;
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int len, type;
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{
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register struct hostent *p;
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_sethtent(0);
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while ((p = _gethtent()) != NULL)
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if (p->h_addrtype == type && !memcmp(p->h_addr, addr, len))
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break;
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_endhtent();
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if (p==NULL)
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h_errno = HOST_NOT_FOUND;
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return (p);
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}
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