distrib/utils/libhack/gethost.c

   1 /*      $NetBSD: gethost.c,v 1.7 2001/06/15 17:26:51 tsutsui Exp $      */
   2
   3 /*-
   4  * Copyright (c) 1985, 1988, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  * -
  31  * Portions Copyright (c) 1993 by Digital Equipment Corporation.
  32  *
  33  * Permission to use, copy, modify, and distribute this software for any
  34  * purpose with or without fee is hereby granted, provided that the above
  35  * copyright notice and this permission notice appear in all copies, and that
  36  * the name of Digital Equipment Corporation not be used in advertising or
  37  * publicity pertaining to distribution of the document or software without
  38  * specific, written prior permission.
  39  *
  40  * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
  41  * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
  42  * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
  43  * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  44  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  45  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  46  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  47  * SOFTWARE.
  48  * -
  49  * --Copyright--
  50  */
  51
  52 /*
  53  * Copied from:  lib/libc/net/gethostnamadr.c
  54  * and then gutted, leaving only /etc/hosts support.
  55  */
  56
  57 #include <sys/cdefs.h>
  58
  59 #ifdef __weak_alias
  60 #define gethostbyaddr           _gethostbyaddr
  61 #define gethostbyname           _gethostbyname
  62 #endif
  63
  64 #include <sys/param.h>
  65 #include <sys/socket.h>
  66 #include <netinet/in.h>
  67 #include <arpa/inet.h>
  68 #include <arpa/nameser.h>
  69 #include <netdb.h>
  70 #include <resolv.h>
  71 #include <stdio.h>
  72 #include <ctype.h>
  73 #include <errno.h>
  74 #include <string.h>
  75
  76 #ifdef __weak_alias
  77 __weak_alias(gethostbyaddr,_gethostbyaddr);
  78 __weak_alias(gethostbyname,_gethostbyname);
  79 #endif
  80
  81 #define MAXALIASES      35
  82 #define MAXADDRS        35
  83
  84 static char *h_addr_ptrs[MAXADDRS + 1];
  85
  86 static struct hostent host;
  87 static char *host_aliases[MAXALIASES];
  88 static char hostbuf[BUFSIZ+1];
  89 static struct in_addr host_addr;
  90 static FILE *hostf = NULL;
  91 static int stayopen = 0;
  92
  93 void _sethtent __P((int));
  94 void _endhtent __P((void));
  95 struct hostent *_gethtent __P((void));
  96 struct hostent *_gethtbyname __P((const char *));
  97 struct hostent *_gethtbyaddr __P((const char *, int, int));
  98
  99
 100 #if PACKETSZ > 1024
 101 #define MAXPACKET       PACKETSZ
 102 #else
 103 #define MAXPACKET       1024
 104 #endif
 105
 106 extern int h_errno;
 107
 108 struct hostent *
 109 gethostbyname(name)
 110         const char *name;
 111 {
 112         register const char *cp;
 113
 114         /*
 115          * disallow names consisting only of digits/dots, unless
 116          * they end in a dot.
 117          */
 118         if (isdigit(name[0]))
 119                 for (cp = name;; ++cp) {
 120                         if (!*cp) {
 121                                 if (*--cp == '.')
 122                                         break;
 123                                 /*
 124                                  * All-numeric, no dot at the end.
 125                                  * Fake up a hostent as if we'd actually
 126                                  * done a lookup.
 127                                  */
 128                                 if (!inet_aton(name, &host_addr)) {
 129                                         h_errno = HOST_NOT_FOUND;
 130                                         return((struct hostent *) NULL);
 131                                 }
 132                                 host.h_name = (char *)name;
 133                                 host.h_aliases = host_aliases;
 134                                 host_aliases[0] = NULL;
 135                                 host.h_addrtype = AF_INET;
 136                                 host.h_length = sizeof(u_int32_t);
 137                                 h_addr_ptrs[0] = (char *)&host_addr;
 138                                 h_addr_ptrs[1] = NULL;
 139                                 host.h_addr_list = h_addr_ptrs;
 140                                 return (&host);
 141                         }
 142                         if (!isdigit(*cp) && *cp != '.')
 143                                 break;
 144                 }
 145
 146         /* XXX - Force host table lookup. */
 147         return (_gethtbyname(name));
 148 }
 149
 150 struct hostent *
 151 gethostbyaddr(addr, len, type)
 152         const char *addr;
 153         socklen_t len;
 154         int type;
 155 {
 156         char qbuf[MAXDNAME];
 157
 158         if (type != AF_INET)
 159                 return ((struct hostent *) NULL);
 160         (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
 161                 ((unsigned)addr[3] & 0xff),
 162                 ((unsigned)addr[2] & 0xff),
 163                 ((unsigned)addr[1] & 0xff),
 164                 ((unsigned)addr[0] & 0xff));
 165
 166         /* XXX - Force host table lookup. */
 167         return (_gethtbyaddr(addr, len, type));
 168 }
 169
 170 void
 171 _sethtent(f)
 172         int f;
 173 {
 174         if (hostf == NULL)
 175                 hostf = fopen(_PATH_HOSTS, "r" );
 176         else
 177                 rewind(hostf);
 178         stayopen = f;
 179 }
 180
 181 void
 182 _endhtent()
 183 {
 184         if (hostf && !stayopen) {
 185                 (void) fclose(hostf);
 186                 hostf = NULL;
 187         }
 188 }
 189
 190 struct hostent *
 191 _gethtent()
 192 {
 193         char *p;
 194         register char *cp, **q;
 195
 196         if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
 197                 return (NULL);
 198 again:
 199         if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
 200                 return (NULL);
 201         if (*p == '#')
 202                 goto again;
 203         cp = strpbrk(p, "#\n");
 204         if (cp == NULL)
 205                 goto again;
 206         *cp = '\0';
 207         cp = strpbrk(p, " \t");
 208         if (cp == NULL)
 209                 goto again;
 210         *cp++ = '\0';
 211         /* THIS STUFF IS INTERNET SPECIFIC */
 212         h_addr_ptrs[0] = (char *)&host_addr;
 213         h_addr_ptrs[1] = NULL;
 214         (void) inet_aton(p, &host_addr);
 215         host.h_addr_list = h_addr_ptrs;
 216         host.h_length = sizeof(u_int32_t);
 217         host.h_addrtype = AF_INET;
 218         while (*cp == ' ' || *cp == '\t')
 219                 cp++;
 220         host.h_name = cp;
 221         q = host.h_aliases = host_aliases;
 222         cp = strpbrk(cp, " \t");
 223         if (cp != NULL)
 224                 *cp++ = '\0';
 225         while (cp && *cp) {
 226                 if (*cp == ' ' || *cp == '\t') {
 227                         cp++;
 228                         continue;
 229                 }
 230                 if (q < &host_aliases[MAXALIASES - 1])
 231                         *q++ = cp;
 232                 cp = strpbrk(cp, " \t");
 233                 if (cp != NULL)
 234                         *cp++ = '\0';
 235         }
 236         *q = NULL;
 237         return (&host);
 238 }
 239
 240 struct hostent *
 241 _gethtbyname(name)
 242         const char *name;
 243 {
 244         register struct hostent *p;
 245         register char **cp;
 246
 247         _sethtent(0);
 248         while ((p = _gethtent()) != NULL) {
 249                 if (strcasecmp(p->h_name, name) == 0)
 250                         break;
 251                 for (cp = p->h_aliases; *cp != 0; cp++)
 252                         if (strcasecmp(*cp, name) == 0)
 253                                 goto found;
 254         }
 255 found:
 256         _endhtent();
 257         if (p==NULL)
 258                 h_errno = HOST_NOT_FOUND;
 259         return (p);
 260 }
 261
 262 struct hostent *
 263 _gethtbyaddr(addr, len, type)
 264         const char *addr;
 265         int len, type;
 266 {
 267         register struct hostent *p;
 268
 269         _sethtent(0);
 270         while ((p = _gethtent()) != NULL)
 271                 if (p->h_addrtype == type && !memcmp(p->h_addr, addr, len))
 272                         break;
 273         _endhtent();
 274         if (p==NULL)
 275                 h_errno = HOST_NOT_FOUND;
 276         return (p);
 277 }
 278