1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" /* SMI4.1 1.7 */ 27 28 #include <stdio.h> 29 #include <ndbm.h> 30 #include <netdb.h> 31 #include <sys/types.h> 32 #include <sys/socket.h> 33 #include <netinet/in.h> 34 #include <arpa/inet.h> 35 #include <string.h> 36 #include <ctype.h> 37 #include <errno.h> 38 39 /* 40 * Filter to convert both IPv4 and IPv6 addresses from /etc/hosts file. 41 */ 42 43 /* 44 * Size of buffer for input lines. Add two bytes on input for newline 45 * and terminating NULL. Note that the practical limit for data 46 * storage in ndbm is (PBLKSIZ - 3 * sizeof (short)). Though this 47 * differs from spec 1170 the common industry implementation does 48 * conform to this slightly lower limit. 49 */ 50 51 #define OUTPUTSIZ (PBLKSIZ - 3 * sizeof (short)) 52 #define INPUTSIZ (OUTPUTSIZ + 2) 53 54 static int ipv4 = -1; 55 static char *cmd; 56 int warning = 0; 57 58 static void verify_and_output(const char *key, char *value, int lineno); 59 60 void 61 usage() 62 { 63 fprintf(stderr, "stdhosts [-w] [-n] [in-file]\n"); 64 fprintf(stderr, "\t-w\tprint malformed warning messages.\n"); 65 exit(1); 66 } 67 68 int 69 main(argc, argv) 70 char **argv; 71 { 72 char line[INPUTSIZ]; 73 char adr[INPUTSIZ]; 74 char nadr[INET6_ADDRSTRLEN]; /* Contains normalised address */ 75 const char *nadrp; /* Pointer to the normalised address */ 76 char *trailer; 77 char *commentp; /* Pointer to comment character '#' */ 78 int c; 79 FILE *fp; 80 int lineno = 0; /* Input line counter */ 81 struct in_addr in; /* Used for normalising the IPv4 address */ 82 struct in6_addr in6; /* Used for normalising the IPv6 address */ 83 char *fgetsp; /* Holds return value for fgets() calls */ 84 int endoffile = 0; /* Set when end of file reached */ 85 86 if (cmd = strrchr(argv[0], '/')) 87 ++cmd; 88 else 89 cmd = argv[0]; 90 91 while ((c = getopt(argc, argv, "v:wn")) != -1) { 92 switch (c) { 93 case 'w': /* Send warning messages to stderr */ 94 warning = 1; 95 break; 96 case 'n': 97 ipv4 = 0; 98 break; 99 default: 100 usage(); 101 exit(1); 102 } 103 } 104 105 if (optind < argc) { 106 fp = fopen(argv[optind], "r"); 107 if (fp == NULL) { 108 fprintf(stderr, "%s: can't open %s\n", 109 cmd, argv[optind]); 110 exit(1); 111 } 112 } else 113 fp = stdin; 114 115 while (!endoffile && 116 (fgetsp = fgets(line, sizeof (line), fp)) != NULL) { 117 lineno++; 118 119 /* Check for comments */ 120 if ((commentp = strchr(line, '#')) != NULL) { 121 if ((line[strlen(line) - 1] != '\n') && 122 (strlen(line) >= (sizeof (line) - 1))) { 123 /* 124 * Discard the remainder of the line 125 * until the newline or EOF, then 126 * continue to parse the line. Use 127 * adr[] rather then line[] to 128 * preserve the contents of line[]. 129 */ 130 while ((fgetsp = fgets(adr, sizeof (adr), 131 fp)) != NULL) { 132 if (adr[strlen(adr) - 1] == '\n') 133 break; 134 } 135 if (fgetsp == NULL) 136 endoffile = 1; 137 } 138 /* Terminate line[] at the comment character */ 139 *commentp = '\0'; 140 } else if ((line[strlen(line) - 1] != '\n') && 141 (strlen(line) >= (sizeof (line) - 1))) { 142 /* 143 * Catch long lines but not if this is a short 144 * line with no '\n' at the end of the input. 145 */ 146 if (warning) 147 fprintf(stderr, 148 "%s: Warning: more than %d " 149 "bytes on line %d, ignored\n", 150 cmd, sizeof (line) - 2, lineno); 151 /* 152 * Discard the remaining lines until the 153 * newline or EOF. 154 */ 155 while ((fgetsp = fgets(line, sizeof (line), 156 fp)) != NULL) 157 if (line[strlen(line) - 1] == '\n') 158 break; 159 if (fgetsp == NULL) 160 endoffile = 1; 161 continue; 162 } 163 164 if (sscanf(line, "%s", adr) != 1) { /* Blank line, ignore */ 165 continue; 166 } 167 168 if ((trailer = strpbrk(line, " \t")) == NULL) { 169 if (warning) 170 fprintf(stderr, 171 "%s: Warning: no host names on line %d, " 172 "ignored\n", cmd, lineno); 173 continue; 174 } 175 176 /* 177 * check for valid addresses 178 * 179 * Attempt an ipv4 conversion, this accepts all valid 180 * ipv4 addresses including: 181 * d 182 * d.d 183 * d.d.d 184 * Unfortunately inet_pton() doesn't recognise these. 185 */ 186 187 in.s_addr = inet_addr(adr); 188 if (-1 != (int)in.s_addr) { 189 /* 190 * It's safe not to check return of NULL as 191 * nadrp is checked for validity later. 192 */ 193 nadrp = inet_ntop(AF_INET, &in, nadr, sizeof (nadr)); 194 } else { 195 nadrp = NULL; /* Not a valid IPv4 address */ 196 } 197 198 if (nadrp == NULL) { 199 if (inet_pton(AF_INET6, adr, &in6) == 1) { 200 nadrp = inet_ntop(AF_INET6, &in6, 201 nadr, sizeof (nadr)); 202 } 203 if (nadrp == NULL) { /* Invalid IPv6 too */ 204 if (warning) 205 fprintf(stderr, 206 "%s: Warning: malformed" 207 " address on" 208 " line %d, ignored\n", 209 cmd, lineno); 210 continue; 211 } else if (ipv4) { 212 continue; /* Ignore valid IPv6 */ 213 } 214 } 215 216 verify_and_output(nadrp, trailer, lineno); 217 218 } /* while */ 219 return (0); 220 /* NOTREACHED */ 221 } 222 223 /* 224 * verify_and_output 225 * 226 * Builds and verifies the output key and value string 227 * 228 * It makes sure these rules are followed: 229 * key + separator + value <= OUTPUTSIZ (for ndbm) 230 * names <= MAXALIASES + 1, ie one canonical name + MAXALIASES aliases 231 * It will also ignore everything after a '#' comment character 232 */ 233 static void 234 verify_and_output(const char *key, char *value, int lineno) 235 { 236 char *p; /* General char pointer */ 237 char *endp; /* Points to the NULL at the end */ 238 char *namep; /* First character of a name */ 239 char tmpbuf[OUTPUTSIZ+1]; /* Buffer before writing out */ 240 char *tmpbufp = tmpbuf; /* Current point in output string */ 241 int n = 0; /* Length of output */ 242 int names = 0; /* Number of names found */ 243 int namelen; /* Length of the name */ 244 245 if (key) { /* Just in case key is NULL */ 246 n = strlen(key); 247 if (n > OUTPUTSIZ) { 248 if (warning) 249 fprintf(stderr, 250 "%s: address too long on " 251 "line %d, line discarded\n", 252 cmd, lineno); 253 return; 254 } 255 memcpy(tmpbufp, key, n+1); /* Plus the '\0' */ 256 tmpbufp += n; 257 } 258 259 if (value) { /* Just in case value is NULL */ 260 p = value; 261 if ((endp = strchr(value, '#')) == 0) /* Ignore # comments */ 262 endp = p + strlen(p); /* Or endp = EOL */ 263 do { 264 /* 265 * Skip white space. Type conversion is 266 * necessary to avoid unfortunate effects of 267 * 8-bit characters appearing negative. 268 */ 269 while ((p < endp) && isspace((unsigned char)*p)) 270 p++; 271 272 if (p == endp) /* End of the string */ 273 break; 274 275 names++; 276 if (names > (MAXALIASES+1)) { /* cname + MAXALIASES */ 277 if (warning) 278 fprintf(stderr, 279 "%s: Warning: too many " 280 "host names on line %d, " 281 "truncating\n", 282 cmd, lineno); 283 break; 284 } 285 286 namep = p; 287 while ((p < endp) && !isspace((unsigned char)*p)) 288 p++; 289 290 namelen = p - namep; 291 n += namelen + 1; /* single white space + name */ 292 *p = '\0'; /* Terminate the name string */ 293 if (n > OUTPUTSIZ) { 294 if (warning) 295 fprintf(stderr, 296 "%s: Warning: %d byte ndbm limit " 297 "reached on line %d, truncating\n", 298 cmd, OUTPUTSIZ, lineno); 299 break; 300 } 301 302 if (names == 1) /* First space is a '\t' */ 303 *tmpbufp++ = '\t'; 304 else 305 *tmpbufp++ = ' '; 306 307 memcpy(tmpbufp, namep, namelen+1); /* Plus the '\0' */ 308 tmpbufp += namelen; 309 310 if (p < endp) 311 p++; /* Skip the added NULL */ 312 313 } while (p < endp); 314 } 315 316 if (names > 0) { 317 fputs(tmpbuf, stdout); 318 fputc('\n', stdout); 319 } else { 320 if (warning) 321 fprintf(stderr, 322 "%s: Warning: no host names on line %d, " 323 "ignored\n", cmd, lineno); 324 } 325 } 326