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Cream of the Crop 20
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Cream of the Crop 20 (Terry Blount) (1996).iso
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gethnamaddr.c
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C/C++ Source or Header
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1995-08-22
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18KB
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780 lines
/*
* ++Copyright++ 1985, 1988, 1993
* -
* Copyright (c) 1985, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* 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 University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
* -
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
* -
* --Copyright--
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$Id: gethnamaddr.c,v 8.7 1995/08/22 05:01:47 vixie Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <stdio.h>
#include <netdb.h>
#include <resolv.h>
#include <ctype.h>
#include <errno.h>
#include <syslog.h>
#ifndef LOG_AUTH
# define LOG_AUTH 0
#endif
#define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */
#if defined(BSD) && (BSD >= 199103)
# include <string.h>
#else
# include "../conf/portability.h"
#endif
#if defined(USE_OPTIONS_H)
# include <../conf/options.h>
#endif
#define MAXALIASES 35
#define MAXADDRS 35
static const char AskedForGot[] =
"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
static char *h_addr_ptrs[MAXADDRS + 1];
static struct hostent *gethostbyname_ipv4 __P((const char *));
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[8*1024];
static struct in_addr host_addr;
static FILE *hostf = NULL;
static int stayopen = 0;
#ifdef RESOLVSORT
static void addrsort __P((char **, int));
#endif
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
typedef union {
int32_t al;
char ac;
} align;
extern int h_errno;
#ifdef DEBUG
static void
dprintf(msg, num)
char *msg;
int num;
{
if (_res.options & RES_DEBUG) {
int save = errno;
printf(msg, num);
errno = save;
}
}
#else
# define dprintf(msg, num) /*nada*/
#endif
static struct hostent *
getanswer(answer, anslen, qname, qclass, qtype)
const querybuf *answer;
int anslen;
const char *qname;
int qclass, qtype;
{
register const HEADER *hp;
register const u_char *cp;
register int n;
const u_char *eom;
char *bp, **ap, **hap;
int type, class, buflen, ancount, qdcount;
int haveanswer, had_error;
int toobig = 0;
char tbuf[MAXDNAME+1];
const char *tname;
tname = qname;
host.h_name = NULL;
eom = answer->buf + anslen;
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
bp = hostbuf;
buflen = sizeof hostbuf;
cp = answer->buf + HFIXEDSZ;
if (qdcount != 1) {
h_errno = NO_RECOVERY;
return (NULL);
}
if ((n = dn_expand(answer->buf, eom, cp, bp, buflen)) < 0) {
h_errno = NO_RECOVERY;
return (NULL);
}
cp += n + QFIXEDSZ;
if (qtype == T_A) {
/* res_send() has already verified that the query name is the
* same as the one we sent; this just gets the expanded name
* (i.e., with the succeeding search-domain tacked on).
*/
n = strlen(bp) + 1; /* for the \0 */
host.h_name = bp;
bp += n;
buflen -= n;
/* The qname can be abbreviated, but h_name is now absolute. */
qname = host.h_name;
}
ap = host_aliases;
*ap = NULL;
host.h_aliases = host_aliases;
hap = h_addr_ptrs;
*hap = NULL;
#if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
host.h_addr_list = h_addr_ptrs;
#endif
haveanswer = 0;
had_error = 0;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(answer->buf, eom, cp, bp, buflen);
if (n < 0) {
had_error++;
continue;
}
cp += n; /* name */
type = _getshort(cp);
cp += INT16SZ; /* type */
class = _getshort(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = _getshort(cp);
cp += INT16SZ; /* len */
if (class != qclass) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if (qtype == T_A && type == T_CNAME) {
if (ap >= &host_aliases[MAXALIASES-1])
continue;
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if (n < 0) {
had_error++;
continue;
}
cp += n;
if (host.h_name && strcasecmp(host.h_name, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s\", got CNAME for \"%s\"",
host.h_name, bp);
continue; /* XXX - had_error++ ? */
}
/* Store alias. */
*ap++ = bp;
n = strlen(bp) + 1; /* for the \0 */
bp += n;
buflen -= n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > buflen) {
had_error++;
continue;
}
strcpy(bp, tbuf);
host.h_name = bp;
bp += n;
buflen -= n;
continue;
}
if (qtype == T_PTR && type == T_CNAME) {
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if (n < 0) {
had_error++;
continue;
}
cp += n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > buflen) {
had_error++;
continue;
}
strcpy(bp, tbuf);
tname = bp;
bp += n;
buflen -= n;
continue;
}
if (type != qtype) {
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
qname, p_class(qclass), p_type(qtype),
p_type(type));
cp += n;
continue; /* XXX - had_error++ ? */
}
switch (type) {
case T_PTR:
if (strcasecmp(tname, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, qname, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
n = dn_expand(answer->buf