NetBSD-5.0.2/distrib/utils/libhack/gethost.c
/* $NetBSD: gethost.c,v 1.8 2003/08/07 09:27:57 agc Exp $ */
/*-
* 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. 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--
*/
/*
* Copied from: lib/libc/net/gethostnamadr.c
* and then gutted, leaving only /etc/hosts support.
*/
#include <sys/cdefs.h>
#ifdef __weak_alias
#define gethostbyaddr _gethostbyaddr
#define gethostbyname _gethostbyname
#endif
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#ifdef __weak_alias
__weak_alias(gethostbyaddr,_gethostbyaddr);
__weak_alias(gethostbyname,_gethostbyname);
#endif
#define MAXALIASES 35
#define MAXADDRS 35
static char *h_addr_ptrs[MAXADDRS + 1];
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[BUFSIZ+1];
static struct in_addr host_addr;
static FILE *hostf = NULL;
static int stayopen = 0;
void _sethtent __P((int));
void _endhtent __P((void));
struct hostent *_gethtent __P((void));
struct hostent *_gethtbyname __P((const char *));
struct hostent *_gethtbyaddr __P((const char *, int, int));
#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif
extern int h_errno;
struct hostent *
gethostbyname(name)
const char *name;
{
register const char *cp;
/*
* disallow names consisting only of digits/dots, unless
* they end in a dot.
*/
if (isdigit(name[0]))
for (cp = name;; ++cp) {
if (!*cp) {
if (*--cp == '.')
break;
/*
* All-numeric, no dot at the end.
* Fake up a hostent as if we'd actually
* done a lookup.
*/
if (!inet_aton(name, &host_addr)) {
h_errno = HOST_NOT_FOUND;
return((struct hostent *) NULL);
}
host.h_name = (char *)name;
host.h_aliases = host_aliases;
host_aliases[0] = NULL;
host.h_addrtype = AF_INET;
host.h_length = sizeof(u_int32_t);
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = NULL;
host.h_addr_list = h_addr_ptrs;
return (&host);
}
if (!isdigit(*cp) && *cp != '.')
break;
}
/* XXX - Force host table lookup. */
return (_gethtbyname(name));
}
struct hostent *
gethostbyaddr(addr, len, type)
const char *addr;
socklen_t len;
int type;
{
char qbuf[MAXDNAME];
if (type != AF_INET)
return ((struct hostent *) NULL);
(void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
((unsigned)addr[3] & 0xff),
((unsigned)addr[2] & 0xff),
((unsigned)addr[1] & 0xff),
((unsigned)addr[0] & 0xff));
/* XXX - Force host table lookup. */
return (_gethtbyaddr(addr, len, type));
}
void
_sethtent(f)
int f;
{
if (hostf == NULL)
hostf = fopen(_PATH_HOSTS, "r" );
else
rewind(hostf);
stayopen = f;
}
void
_endhtent()
{
if (hostf && !stayopen) {
(void) fclose(hostf);
hostf = NULL;
}
}
struct hostent *
_gethtent()
{
char *p;
register char *cp, **q;
if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
return (NULL);
again:
if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
return (NULL);
if (*p == '#')
goto again;
cp = strpbrk(p, "#\n");
if (cp == NULL)
goto again;
*cp = '\0';
cp = strpbrk(p, " \t");
if (cp == NULL)
goto again;
*cp++ = '\0';
/* THIS STUFF IS INTERNET SPECIFIC */
h_addr_ptrs[0] = (char *)&host_addr;
h_addr_ptrs[1] = NULL;
(void) inet_aton(p, &host_addr);
host.h_addr_list = h_addr_ptrs;
host.h_length = sizeof(u_int32_t);
host.h_addrtype = AF_INET;
while (*cp == ' ' || *cp == '\t')
cp++;
host.h_name = cp;
q = host.h_aliases = host_aliases;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (q < &host_aliases[MAXALIASES - 1])
*q++ = cp;
cp = strpbrk(cp, " \t");
if (cp != NULL)
*cp++ = '\0';
}
*q = NULL;
return (&host);
}
struct hostent *
_gethtbyname(name)
const char *name;
{
register struct hostent *p;
register char **cp;
_sethtent(0);
while ((p = _gethtent()) != NULL) {
if (strcasecmp(p->h_name, name) == 0)
break;
for (cp = p->h_aliases; *cp != 0; cp++)
if (strcasecmp(*cp, name) == 0)
goto found;
}
found:
_endhtent();
if (p==NULL)
h_errno = HOST_NOT_FOUND;
return (p);
}
struct hostent *
_gethtbyaddr(addr, len, type)
const char *addr;
int len, type;
{
register struct hostent *p;
_sethtent(0);
while ((p = _gethtent()) != NULL)
if (p->h_addrtype == type && !memcmp(p->h_addr, addr, len))
break;
_endhtent();
if (p==NULL)
h_errno = HOST_NOT_FOUND;
return (p);
}