gethost.c revision 1.3
1 /* $NetBSD: gethost.c,v 1.3 1998/08/10 02:22:30 perry 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 #if PACKETSZ > 1024 86 #define MAXPACKET PACKETSZ 87 #else 88 #define MAXPACKET 1024 89 #endif 90 91 extern int h_errno; 92 93 struct hostent * 94 gethostbyname(name) 95 const char *name; 96 { 97 register const char *cp; 98 int n, i; 99 extern struct hostent *_gethtbyname(); 100 101 /* 102 * disallow names consisting only of digits/dots, unless 103 * they end in a dot. 104 */ 105 if (isdigit(name[0])) 106 for (cp = name;; ++cp) { 107 if (!*cp) { 108 if (*--cp == '.') 109 break; 110 /* 111 * All-numeric, no dot at the end. 112 * Fake up a hostent as if we'd actually 113 * done a lookup. 114 */ 115 if (!inet_aton(name, &host_addr)) { 116 h_errno = HOST_NOT_FOUND; 117 return((struct hostent *) NULL); 118 } 119 host.h_name = (char *)name; 120 host.h_aliases = host_aliases; 121 host_aliases[0] = NULL; 122 host.h_addrtype = AF_INET; 123 host.h_length = sizeof(u_int32_t); 124 h_addr_ptrs[0] = (char *)&host_addr; 125 h_addr_ptrs[1] = NULL; 126 host.h_addr_list = h_addr_ptrs; 127 return (&host); 128 } 129 if (!isdigit(*cp) && *cp != '.') 130 break; 131 } 132 133 /* XXX - Force host table lookup. */ 134 return (_gethtbyname(name)); 135 } 136 137 struct hostent * 138 gethostbyaddr(addr, len, type) 139 const char *addr; 140 int len, type; 141 { 142 int n, i; 143 char qbuf[MAXDNAME]; 144 extern struct hostent *_gethtbyaddr(); 145 146 if (type != AF_INET) 147 return ((struct hostent *) NULL); 148 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", 149 ((unsigned)addr[3] & 0xff), 150 ((unsigned)addr[2] & 0xff), 151 ((unsigned)addr[1] & 0xff), 152 ((unsigned)addr[0] & 0xff)); 153 154 /* XXX - Force host table lookup. */ 155 return (_gethtbyaddr(addr, len, type)); 156 } 157 158 void 159 _sethtent(f) 160 int f; 161 { 162 if (hostf == NULL) 163 hostf = fopen(_PATH_HOSTS, "r" ); 164 else 165 rewind(hostf); 166 stayopen = f; 167 } 168 169 void 170 _endhtent() 171 { 172 if (hostf && !stayopen) { 173 (void) fclose(hostf); 174 hostf = NULL; 175 } 176 } 177 178 struct hostent * 179 _gethtent() 180 { 181 char *p; 182 register char *cp, **q; 183 184 if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL) 185 return (NULL); 186 again: 187 if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL) 188 return (NULL); 189 if (*p == '#') 190 goto again; 191 cp = strpbrk(p, "#\n"); 192 if (cp == NULL) 193 goto again; 194 *cp = '\0'; 195 cp = strpbrk(p, " \t"); 196 if (cp == NULL) 197 goto again; 198 *cp++ = '\0'; 199 /* THIS STUFF IS INTERNET SPECIFIC */ 200 h_addr_ptrs[0] = (char *)&host_addr; 201 h_addr_ptrs[1] = NULL; 202 (void) inet_aton(p, &host_addr); 203 host.h_addr_list = h_addr_ptrs; 204 host.h_length = sizeof(u_int32_t); 205 host.h_addrtype = AF_INET; 206 while (*cp == ' ' || *cp == '\t') 207 cp++; 208 host.h_name = cp; 209 q = host.h_aliases = host_aliases; 210 cp = strpbrk(cp, " \t"); 211 if (cp != NULL) 212 *cp++ = '\0'; 213 while (cp && *cp) { 214 if (*cp == ' ' || *cp == '\t') { 215 cp++; 216 continue; 217 } 218 if (q < &host_aliases[MAXALIASES - 1]) 219 *q++ = cp; 220 cp = strpbrk(cp, " \t"); 221 if (cp != NULL) 222 *cp++ = '\0'; 223 } 224 *q = NULL; 225 return (&host); 226 } 227 228 struct hostent * 229 _gethtbyname(name) 230 char *name; 231 { 232 register struct hostent *p; 233 register char **cp; 234 235 _sethtent(0); 236 while (p = _gethtent()) { 237 if (strcasecmp(p->h_name, name) == 0) 238 break; 239 for (cp = p->h_aliases; *cp != 0; cp++) 240 if (strcasecmp(*cp, name) == 0) 241 goto found; 242 } 243 found: 244 _endhtent(); 245 if (p==NULL) 246 h_errno = HOST_NOT_FOUND; 247 return (p); 248 } 249 250 struct hostent * 251 _gethtbyaddr(addr, len, type) 252 const char *addr; 253 int len, type; 254 { 255 register struct hostent *p; 256 257 _sethtent(0); 258 while (p = _gethtent()) 259 if (p->h_addrtype == type && !memcmp(p->h_addr, addr, len)) 260 break; 261 _endhtent(); 262 if (p==NULL) 263 h_errno = HOST_NOT_FOUND; 264 return (p); 265 } 266 267
Indexes created Fri Sep 26 08:10:20 GMT 2025