gethost.c revision 1.4
1 /* $NetBSD: gethost.c,v 1.4 1999/03/13 19:08:44 sommerfe 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * - 35 * Portions Copyright (c) 1993 by Digital Equipment Corporation. 36 * 37 * Permission to use, copy, modify, and distribute this software for any 38 * purpose with or without fee is hereby granted, provided that the above 39 * copyright notice and this permission notice appear in all copies, and that 40 * the name of Digital Equipment Corporation not be used in advertising or 41 * publicity pertaining to distribution of the document or software without 42 * specific, written prior permission. 43 * 44 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL 45 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES 46 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT 47 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 48 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 49 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 50 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 51 * SOFTWARE. 52 * - 53 * --Copyright-- 54 */ 55 56 /* 57 * Copied from: lib/libc/net/gethostnamadr.c 58 * and then gutted, leaving only /etc/hosts support. 59 */ 60 61 #include <sys/param.h> 62 #include <sys/socket.h> 63 #include <netinet/in.h> 64 #include <arpa/inet.h> 65 #include <arpa/nameser.h> 66 #include <netdb.h> 67 #include <resolv.h> 68 #include <stdio.h> 69 #include <ctype.h> 70 #include <errno.h> 71 #include <string.h> 72 73 #define MAXALIASES 35 74 #define MAXADDRS 35 75 76 static char *h_addr_ptrs[MAXADDRS + 1]; 77 78 static struct hostent host; 79 static char *host_aliases[MAXALIASES]; 80 static char hostbuf[BUFSIZ+1]; 81 static struct in_addr host_addr; 82 static FILE *hostf = NULL; 83 static int stayopen = 0; 84 85 void _sethtent __P((int)); 86 void _endhtent __P((void)); 87 struct hostent *_gethtent __P((void)); 88 struct hostent *_gethtbyname __P((const char *)); 89 struct hostent *_gethtbyaddr __P((const char *, int, int)); 90 91 92 #if PACKETSZ > 1024 93 #define MAXPACKET PACKETSZ 94 #else 95 #define MAXPACKET 1024 96 #endif 97 98 extern int h_errno; 99 100 struct hostent * 101 gethostbyname(name) 102 const char *name; 103 { 104 register const char *cp; 105 106 /* 107 * disallow names consisting only of digits/dots, unless 108 * they end in a dot. 109 */ 110 if (isdigit(name[0])) 111 for (cp = name;; ++cp) { 112 if (!*cp) { 113 if (*--cp == '.') 114 break; 115 /* 116 * All-numeric, no dot at the end. 117 * Fake up a hostent as if we'd actually 118 * done a lookup. 119 */ 120 if (!inet_aton(name, &host_addr)) { 121 h_errno = HOST_NOT_FOUND; 122 return((struct hostent *) NULL); 123 } 124 host.h_name = (char *)name; 125 host.h_aliases = host_aliases; 126 host_aliases[0] = NULL; 127 host.h_addrtype = AF_INET; 128 host.h_length = sizeof(u_int32_t); 129 h_addr_ptrs[0] = (char *)&host_addr; 130 h_addr_ptrs[1] = NULL; 131 host.h_addr_list = h_addr_ptrs; 132 return (&host); 133 } 134 if (!isdigit(*cp) && *cp != '.') 135 break; 136 } 137 138 /* XXX - Force host table lookup. */ 139 return (_gethtbyname(name)); 140 } 141 142 struct hostent * 143 gethostbyaddr(addr, len, type) 144 const char *addr; 145 int len, type; 146 { 147 char qbuf[MAXDNAME]; 148 149 if (type != AF_INET) 150 return ((struct hostent *) NULL); 151 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 152 ((unsigned)addr[3] & 0xff), 153 ((unsigned)addr[2] & 0xff), 154 ((unsigned)addr[1] & 0xff), 155 ((unsigned)addr[0] & 0xff)); 156 157 /* XXX - Force host table lookup. */ 158 return (_gethtbyaddr(addr, len, type)); 159 } 160 161 void 162 _sethtent(f) 163 int f; 164 { 165 if (hostf == NULL) 166 hostf = fopen(_PATH_HOSTS, "r" ); 167 else 168 rewind(hostf); 169 stayopen = f; 170 } 171 172 void 173 _endhtent() 174 { 175 if (hostf && !stayopen) { 176 (void) fclose(hostf); 177 hostf = NULL; 178 } 179 } 180 181 struct hostent * 182 _gethtent() 183 { 184 char *p; 185 register char *cp, **q; 186 187 if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) 188 return (NULL); 189 again: 190 if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) 191 return (NULL); 192 if (*p == '#') 193 goto again; 194 cp = strpbrk(p, "#\n"); 195 if (cp == NULL) 196 goto again; 197 *cp = '\0'; 198 cp = strpbrk(p, " \t"); 199 if (cp == NULL) 200 goto again; 201 *cp++ = '\0'; 202 /* THIS STUFF IS INTERNET SPECIFIC */ 203 h_addr_ptrs[0] = (char *)&host_addr; 204 h_addr_ptrs[1] = NULL; 205 (void) inet_aton(p, &host_addr); 206 host.h_addr_list = h_addr_ptrs; 207 host.h_length = sizeof(u_int32_t); 208 host.h_addrtype = AF_INET; 209 while (*cp == ' ' || *cp == '\t') 210 cp++; 211 host.h_name = cp; 212 q = host.h_aliases = host_aliases; 213 cp = strpbrk(cp, " \t"); 214 if (cp != NULL) 215 *cp++ = '\0'; 216 while (cp && *cp) { 217 if (*cp == ' ' || *cp == '\t') { 218 cp++; 219 continue; 220 } 221 if (q < &host_aliases[MAXALIASES - 1]) 222 *q++ = cp; 223 cp = strpbrk(cp, " \t"); 224 if (cp != NULL) 225 *cp++ = '\0'; 226 } 227 *q = NULL; 228 return (&host); 229 } 230 231 struct hostent * 232 _gethtbyname(name) 233 const char *name; 234 { 235 register struct hostent *p; 236 register char **cp; 237 238 _sethtent(0); 239 while ((p = _gethtent()) != NULL) { 240 if (strcasecmp(p->h_name, name) == 0) 241 break; 242 for (cp = p->h_aliases; *cp != 0; cp++) 243 if (strcasecmp(*cp, name) == 0) 244 goto found; 245 } 246 found: 247 _endhtent(); 248 if (p==NULL) 249 h_errno = HOST_NOT_FOUND; 250 return (p); 251 } 252 253 struct hostent * 254 _gethtbyaddr(addr, len, type) 255 const char *addr; 256 int len, type; 257 { 258 register struct hostent *p; 259 260 _sethtent(0); 261 while ((p = _gethtent()) != NULL) 262 if (p->h_addrtype == type && !memcmp(p->h_addr, addr, len)) 263 break; 264 _endhtent(); 265 if (p==NULL) 266 h_errno = HOST_NOT_FOUND; 267 return (p); 268 } 269 270
Indexes created Thu Sep 25 16:09:42 GMT 2025