434 lines
10 KiB
C
434 lines
10 KiB
C
/*
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* Copyright (c) 1985, 1988 Regents of the University of California.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. 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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)gethostnamadr.c 6.45 (Berkeley) 2/24/91";
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#endif /* LIBC_SCCS and not lint */
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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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#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 char hostaddr[MAXADDRS];
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static char *host_addrs[2];
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static int stayopen = 0;
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char *strpbrk();
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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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typedef union {
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HEADER hdr;
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u_char buf[MAXPACKET];
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} querybuf;
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typedef union {
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long al;
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char ac;
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} align;
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int h_errno;
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static struct hostent *
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getanswer(answer, anslen, iquery)
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querybuf *answer;
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int anslen;
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int iquery;
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{
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register HEADER *hp;
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register u_char *cp;
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register int n;
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u_char *eom;
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char *bp, **ap;
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int type, class, buflen, ancount, qdcount;
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int haveanswer, getclass = C_ANY;
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char **hap;
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eom = answer->buf + anslen;
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/*
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* find first satisfactory answer
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*/
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hp = &answer->hdr;
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ancount = ntohs(hp->ancount);
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qdcount = ntohs(hp->qdcount);
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bp = hostbuf;
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buflen = sizeof(hostbuf);
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cp = answer->buf + sizeof(HEADER);
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if (qdcount) {
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if (iquery) {
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if ((n = dn_expand((u_char *)answer->buf,
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(u_char *)eom, (u_char *)cp, (u_char *)bp,
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buflen)) < 0) {
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h_errno = NO_RECOVERY;
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return ((struct hostent *) NULL);
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}
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cp += n + QFIXEDSZ;
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host.h_name = bp;
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n = strlen(bp) + 1;
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bp += n;
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buflen -= n;
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} else
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cp += __dn_skipname(cp, eom) + QFIXEDSZ;
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while (--qdcount > 0)
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cp += __dn_skipname(cp, eom) + QFIXEDSZ;
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} else if (iquery) {
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if (hp->aa)
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h_errno = HOST_NOT_FOUND;
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else
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h_errno = TRY_AGAIN;
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return ((struct hostent *) NULL);
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}
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ap = host_aliases;
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*ap = NULL;
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host.h_aliases = host_aliases;
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hap = h_addr_ptrs;
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*hap = NULL;
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#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
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host.h_addr_list = h_addr_ptrs;
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#endif
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haveanswer = 0;
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while (--ancount >= 0 && cp < eom) {
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if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom,
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(u_char *)cp, (u_char *)bp, buflen)) < 0)
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break;
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cp += n;
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type = _getshort(cp);
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cp += sizeof(u_short);
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class = _getshort(cp);
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cp += sizeof(u_short) + sizeof(u_long);
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n = _getshort(cp);
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cp += sizeof(u_short);
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if (type == T_CNAME) {
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cp += n;
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if (ap >= &host_aliases[MAXALIASES-1])
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continue;
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*ap++ = bp;
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n = strlen(bp) + 1;
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bp += n;
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buflen -= n;
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continue;
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}
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if (iquery && type == T_PTR) {
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if ((n = dn_expand((u_char *)answer->buf,
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(u_char *)eom, (u_char *)cp, (u_char *)bp,
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buflen)) < 0) {
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cp += n;
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continue;
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}
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cp += n;
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host.h_name = bp;
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return(&host);
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}
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if (iquery || type != T_A) {
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("unexpected answer type %d, size %d\n",
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type, n);
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#endif
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cp += n;
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continue;
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}
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if (haveanswer) {
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if (n != host.h_length) {
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cp += n;
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continue;
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}
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if (class != getclass) {
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cp += n;
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continue;
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}
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} else {
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host.h_length = n;
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getclass = class;
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host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
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if (!iquery) {
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host.h_name = bp;
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bp += strlen(bp) + 1;
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}
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}
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bp += sizeof(align) - ((u_long)bp % sizeof(align));
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if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("size (%d) too big\n", n);
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#endif
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break;
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}
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bcopy(cp, *hap++ = bp, n);
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bp +=n;
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cp += n;
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haveanswer++;
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}
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if (haveanswer) {
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*ap = NULL;
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#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
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*hap = NULL;
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#else
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host.h_addr = h_addr_ptrs[0];
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#endif
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return (&host);
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} else {
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h_errno = TRY_AGAIN;
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return ((struct hostent *) NULL);
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}
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}
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struct hostent *
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gethostbyname(name)
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char *name;
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{
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querybuf buf;
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register char *cp;
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int n;
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extern struct hostent *_gethtbyname();
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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. What if someone types
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* 255.255.255.255? The test below will
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* succeed spuriously... ???
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*/
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if ((host_addr.s_addr = inet_addr(name)) == -1) {
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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 = 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_long);
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = (char *)0;
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#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
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host.h_addr_list = h_addr_ptrs;
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#else
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host.h_addr = h_addr_ptrs[0];
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#endif
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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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if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_search failed\n");
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#endif
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if (errno == ECONNREFUSED)
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return (_gethtbyname(name));
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else
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return ((struct hostent *) NULL);
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}
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return (getanswer(&buf, n, 0));
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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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int len, type;
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{
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int n;
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querybuf buf;
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register struct hostent *hp;
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char qbuf[MAXDNAME];
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extern struct hostent *_gethtbyaddr();
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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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n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf));
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if (n < 0) {
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#ifdef DEBUG
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if (_res.options & RES_DEBUG)
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printf("res_query failed\n");
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#endif
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if (errno == ECONNREFUSED)
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return (_gethtbyaddr(addr, len, type));
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return ((struct hostent *) NULL);
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}
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hp = getanswer(&buf, n, 1);
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if (hp == NULL)
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return ((struct hostent *) NULL);
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hp->h_addrtype = type;
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hp->h_length = len;
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h_addr_ptrs[0] = (char *)&host_addr;
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h_addr_ptrs[1] = (char *)0;
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host_addr = *(struct in_addr *)addr;
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#if BSD < 43 && !defined(h_addr) /* new-style hostent structure */
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hp->h_addr = h_addr_ptrs[0];
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#endif
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return(hp);
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}
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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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_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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#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
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host.h_addr_list = host_addrs;
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#endif
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host.h_addr = hostaddr;
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*((u_long *)host.h_addr) = inet_addr(p);
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host.h_length = sizeof (u_long);
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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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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()) {
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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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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())
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if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len))
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break;
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_endhtent();
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return (p);
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}
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