1 /* $OpenBSD: parse.c,v 1.11 2004/05/05 23:07:47 deraadt Exp $ */ 2 /* $FreeBSD$ */ 3 4 /* Common parser code for dhcpd and dhclient. */ 5 6 /* 7 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of The Internet Software Consortium nor the names 20 * of its contributors may be used to endorse or promote products derived 21 * from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 24 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 27 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 28 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 31 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 32 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * This software has been written for the Internet Software Consortium 38 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 39 * Enterprises. To learn more about the Internet Software Consortium, 40 * see ``http://www.vix.com/isc''. To learn more about Vixie 41 * Enterprises, see ``http://www.vix.com''. 42 */ 43 44 #include "dhcpd.h" 45 #include "dhctoken.h" 46 47 /* Skip to the semicolon ending the current statement. If we encounter 48 * braces, the matching closing brace terminates the statement. If we 49 * encounter a right brace but haven't encountered a left brace, return 50 * leaving the brace in the token buffer for the caller. If we see a 51 * semicolon and haven't seen a left brace, return. This lets us skip 52 * over: 53 * 54 * statement; 55 * statement foo bar { } 56 * statement foo bar { statement { } } 57 * statement} 58 * 59 * ...et cetera. 60 */ 61 void 62 skip_to_semi(FILE *cfile) 63 { 64 int brace_count = 0, token; 65 char *val; 66 67 do { 68 token = peek_token(&val, cfile); 69 if (token == RBRACE) { 70 if (brace_count) { 71 token = next_token(&val, cfile); 72 if (!--brace_count) 73 return; 74 } else 75 return; 76 } else if (token == LBRACE) { 77 brace_count++; 78 } else if (token == SEMI && !brace_count) { 79 token = next_token(&val, cfile); 80 return; 81 } else if (token == '\n') { 82 /* 83 * EOL only happens when parsing 84 * /etc/resolv.conf, and we treat it like a 85 * semicolon because the resolv.conf file is 86 * line-oriented. 87 */ 88 token = next_token(&val, cfile); 89 return; 90 } 91 token = next_token(&val, cfile); 92 } while (token != EOF); 93 } 94 95 int 96 parse_semi(FILE *cfile) 97 { 98 int token; 99 char *val; 100 101 token = next_token(&val, cfile); 102 if (token != SEMI) { 103 parse_warn("semicolon expected."); 104 skip_to_semi(cfile); 105 return (0); 106 } 107 return (1); 108 } 109 110 /* 111 * string-parameter :== STRING SEMI 112 */ 113 char * 114 parse_string(FILE *cfile) 115 { 116 char *val, *s; 117 int token; 118 119 token = next_token(&val, cfile); 120 if (token != STRING) { 121 parse_warn("filename must be a string"); 122 skip_to_semi(cfile); 123 return (NULL); 124 } 125 s = malloc(strlen(val) + 1); 126 if (!s) 127 error("no memory for string %s.", val); 128 strlcpy(s, val, strlen(val) + 1); 129 130 if (!parse_semi(cfile)) 131 return (NULL); 132 return (s); 133 } 134 135 int 136 parse_ip_addr(FILE *cfile, struct iaddr *addr) 137 { 138 addr->len = 4; 139 if (parse_numeric_aggregate(cfile, addr->iabuf, 140 &addr->len, DOT, 10, 8)) 141 return (1); 142 return (0); 143 } 144 145 /* 146 * hardware-parameter :== HARDWARE ETHERNET csns SEMI 147 * csns :== NUMBER | csns COLON NUMBER 148 */ 149 void 150 parse_hardware_param(FILE *cfile, struct hardware *hardware) 151 { 152 unsigned char *t; 153 int token, hlen; 154 char *val; 155 156 token = next_token(&val, cfile); 157 switch (token) { 158 case ETHERNET: 159 hardware->htype = HTYPE_ETHER; 160 break; 161 case TOKEN_RING: 162 hardware->htype = HTYPE_IEEE802; 163 break; 164 case FDDI: 165 hardware->htype = HTYPE_FDDI; 166 break; 167 default: 168 parse_warn("expecting a network hardware type"); 169 skip_to_semi(cfile); 170 return; 171 } 172 173 /* 174 * Parse the hardware address information. Technically, it 175 * would make a lot of sense to restrict the length of the data 176 * we'll accept here to the length of a particular hardware 177 * address type. Unfortunately, there are some broken clients 178 * out there that put bogus data in the chaddr buffer, and we 179 * accept that data in the lease file rather than simply failing 180 * on such clients. Yuck. 181 */ 182 hlen = 0; 183 t = parse_numeric_aggregate(cfile, NULL, &hlen, COLON, 16, 8); 184 if (!t) 185 return; 186 if (hlen > sizeof(hardware->haddr)) { 187 free(t); 188 parse_warn("hardware address too long"); 189 } else { 190 hardware->hlen = hlen; 191 memcpy((unsigned char *)&hardware->haddr[0], t, 192 hardware->hlen); 193 if (hlen < sizeof(hardware->haddr)) 194 memset(&hardware->haddr[hlen], 0, 195 sizeof(hardware->haddr) - hlen); 196 free(t); 197 } 198 199 token = next_token(&val, cfile); 200 if (token != SEMI) { 201 parse_warn("expecting semicolon."); 202 skip_to_semi(cfile); 203 } 204 } 205 206 /* 207 * lease-time :== NUMBER SEMI 208 */ 209 void 210 parse_lease_time(FILE *cfile, time_t *timep) 211 { 212 char *val; 213 int token; 214 215 token = next_token(&val, cfile); 216 if (token != NUMBER) { 217 parse_warn("Expecting numeric lease time"); 218 skip_to_semi(cfile); 219 return; 220 } 221 convert_num((unsigned char *)timep, val, 10, 32); 222 /* Unswap the number - convert_num returns stuff in NBO. */ 223 *timep = ntohl(*timep); /* XXX */ 224 225 parse_semi(cfile); 226 } 227 228 /* 229 * No BNF for numeric aggregates - that's defined by the caller. What 230 * this function does is to parse a sequence of numbers separated by the 231 * token specified in separator. If max is zero, any number of numbers 232 * will be parsed; otherwise, exactly max numbers are expected. Base 233 * and size tell us how to internalize the numbers once they've been 234 * tokenized. 235 */ 236 unsigned char * 237 parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max, 238 int separator, int base, int size) 239 { 240 unsigned char *bufp = buf, *s = NULL; 241 int token, count = 0; 242 char *val, *t; 243 pair c = NULL; 244 245 if (!bufp && *max) { 246 bufp = malloc(*max * size / 8); 247 if (!bufp) 248 error("can't allocate space for numeric aggregate"); 249 } else 250 s = bufp; 251 252 do { 253 if (count) { 254 token = peek_token(&val, cfile); 255 if (token != separator) { 256 if (!*max) 257 break; 258 if (token != RBRACE && token != LBRACE) 259 token = next_token(&val, cfile); 260 parse_warn("too few numbers."); 261 if (token != SEMI) 262 skip_to_semi(cfile); 263 return (NULL); 264 } 265 token = next_token(&val, cfile); 266 } 267 token = next_token(&val, cfile); 268 269 if (token == EOF) { 270 parse_warn("unexpected end of file"); 271 break; 272 } 273 274 /* Allow NUMBER_OR_NAME if base is 16. */ 275 if (token != NUMBER && 276 (base != 16 || token != NUMBER_OR_NAME)) { 277 parse_warn("expecting numeric value."); 278 skip_to_semi(cfile); 279 return (NULL); 280 } 281 /* 282 * If we can, convert the number now; otherwise, build a 283 * linked list of all the numbers. 284 */ 285 if (s) { 286 convert_num(s, val, base, size); 287 s += size / 8; 288 } else { 289 t = malloc(strlen(val) + 1); 290 if (!t) 291 error("no temp space for number."); 292 strlcpy(t, val, strlen(val) + 1); 293 c = cons(t, c); 294 } 295 } while (++count != *max); 296 297 /* If we had to cons up a list, convert it now. */ 298 if (c) { 299 bufp = malloc(count * size / 8); 300 if (!bufp) 301 error("can't allocate space for numeric aggregate."); 302 s = bufp + count - size / 8; 303 *max = count; 304 } 305 while (c) { 306 pair cdr = c->cdr; 307 convert_num(s, (char *)c->car, base, size); 308 s -= size / 8; 309 /* Free up temp space. */ 310 free(c->car); 311 free(c); 312 c = cdr; 313 } 314 return (bufp); 315 } 316 317 void 318 convert_num(unsigned char *buf, char *str, int base, int size) 319 { 320 int negative = 0, tval, max; 321 u_int32_t val = 0; 322 char *ptr = str; 323 324 if (*ptr == '-') { 325 negative = 1; 326 ptr++; 327 } 328 329 /* If base wasn't specified, figure it out from the data. */ 330 if (!base) { 331 if (ptr[0] == '0') { 332 if (ptr[1] == 'x') { 333 base = 16; 334 ptr += 2; 335 } else if (isascii(ptr[1]) && isdigit(ptr[1])) { 336 base = 8; 337 ptr += 1; 338 } else 339 base = 10; 340 } else 341 base = 10; 342 } 343 344 do { 345 tval = *ptr++; 346 /* XXX assumes ASCII... */ 347 if (tval >= 'a') 348 tval = tval - 'a' + 10; 349 else if (tval >= 'A') 350 tval = tval - 'A' + 10; 351 else if (tval >= '0') 352 tval -= '0'; 353 else { 354 warning("Bogus number: %s.", str); 355 break; 356 } 357 if (tval >= base) { 358 warning("Bogus number: %s: digit %d not in base %d", 359 str, tval, base); 360 break; 361 } 362 val = val * base + tval; 363 } while (*ptr); 364 365 if (negative) 366 max = (1 << (size - 1)); 367 else 368 max = (1 << (size - 1)) + ((1 << (size - 1)) - 1); 369 if (val > max) { 370 switch (base) { 371 case 8: 372 warning("value %s%o exceeds max (%d) for precision.", 373 negative ? "-" : "", val, max); 374 break; 375 case 16: 376 warning("value %s%x exceeds max (%d) for precision.", 377 negative ? "-" : "", val, max); 378 break; 379 default: 380 warning("value %s%u exceeds max (%d) for precision.", 381 negative ? "-" : "", val, max); 382 break; 383 } 384 } 385 386 if (negative) 387 switch (size) { 388 case 8: 389 *buf = -(unsigned long)val; 390 break; 391 case 16: 392 putShort(buf, -(unsigned long)val); 393 break; 394 case 32: 395 putLong(buf, -(unsigned long)val); 396 break; 397 default: 398 warning("Unexpected integer size: %d", size); 399 break; 400 } 401 else 402 switch (size) { 403 case 8: 404 *buf = (u_int8_t)val; 405 break; 406 case 16: 407 putUShort(buf, (u_int16_t)val); 408 break; 409 case 32: 410 putULong(buf, val); 411 break; 412 default: 413 warning("Unexpected integer size: %d", size); 414 break; 415 } 416 } 417 418 /* 419 * date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER 420 * NUMBER COLON NUMBER COLON NUMBER SEMI 421 * 422 * Dates are always in GMT; first number is day of week; next is 423 * year/month/day; next is hours:minutes:seconds on a 24-hour 424 * clock. 425 */ 426 time_t 427 parse_date(FILE *cfile) 428 { 429 static int months[11] = { 31, 59, 90, 120, 151, 181, 430 212, 243, 273, 304, 334 }; 431 int guess, token; 432 struct tm tm; 433 char *val; 434 435 /* Day of week... */ 436 token = next_token(&val, cfile); 437 if (token != NUMBER) { 438 parse_warn("numeric day of week expected."); 439 if (token != SEMI) 440 skip_to_semi(cfile); 441 return (0); 442 } 443 tm.tm_wday = atoi(val); 444 445 /* Year... */ 446 token = next_token(&val, cfile); 447 if (token != NUMBER) { 448 parse_warn("numeric year expected."); 449 if (token != SEMI) 450 skip_to_semi(cfile); 451 return (0); 452 } 453 tm.tm_year = atoi(val); 454 if (tm.tm_year > 1900) 455 tm.tm_year -= 1900; 456 457 /* Slash separating year from month... */ 458 token = next_token(&val, cfile); 459 if (token != SLASH) { 460 parse_warn("expected slash separating year from month."); 461 if (token != SEMI) 462 skip_to_semi(cfile); 463 return (0); 464 } 465 466 /* Month... */ 467 token = next_token(&val, cfile); 468 if (token != NUMBER) { 469 parse_warn("numeric month expected."); 470 if (token != SEMI) 471 skip_to_semi(cfile); 472 return (0); 473 } 474 tm.tm_mon = atoi(val) - 1; 475 476 /* Slash separating month from day... */ 477 token = next_token(&val, cfile); 478 if (token != SLASH) { 479 parse_warn("expected slash separating month from day."); 480 if (token != SEMI) 481 skip_to_semi(cfile); 482 return (0); 483 } 484 485 /* Month... */ 486 token = next_token(&val, cfile); 487 if (token != NUMBER) { 488 parse_warn("numeric day of month expected."); 489 if (token != SEMI) 490 skip_to_semi(cfile); 491 return (0); 492 } 493 tm.tm_mday = atoi(val); 494 495 /* Hour... */ 496 token = next_token(&val, cfile); 497 if (token != NUMBER) { 498 parse_warn("numeric hour expected."); 499 if (token != SEMI) 500 skip_to_semi(cfile); 501 return (0); 502 } 503 tm.tm_hour = atoi(val); 504 505 /* Colon separating hour from minute... */ 506 token = next_token(&val, cfile); 507 if (token != COLON) { 508 parse_warn("expected colon separating hour from minute."); 509 if (token != SEMI) 510 skip_to_semi(cfile); 511 return (0); 512 } 513 514 /* Minute... */ 515 token = next_token(&val, cfile); 516 if (token != NUMBER) { 517 parse_warn("numeric minute expected."); 518 if (token != SEMI) 519 skip_to_semi(cfile); 520 return (0); 521 } 522 tm.tm_min = atoi(val); 523 524 /* Colon separating minute from second... */ 525 token = next_token(&val, cfile); 526 if (token != COLON) { 527 parse_warn("expected colon separating hour from minute."); 528 if (token != SEMI) 529 skip_to_semi(cfile); 530 return (0); 531 } 532 533 /* Minute... */ 534 token = next_token(&val, cfile); 535 if (token != NUMBER) { 536 parse_warn("numeric minute expected."); 537 if (token != SEMI) 538 skip_to_semi(cfile); 539 return (0); 540 } 541 tm.tm_sec = atoi(val); 542 tm.tm_isdst = 0; 543 544 /* XXX: We assume that mktime does not use tm_yday. */ 545 tm.tm_yday = 0; 546 547 /* Make sure the date ends in a semicolon... */ 548 token = next_token(&val, cfile); 549 if (token != SEMI) { 550 parse_warn("semicolon expected."); 551 skip_to_semi(cfile); 552 return (0); 553 } 554 555 /* Guess the time value... */ 556 guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */ 557 (tm.tm_year - 69) / 4 + /* Leap days since '70 */ 558 (tm.tm_mon /* Days in months this year */ 559 ? months[tm.tm_mon - 1] 560 : 0) + 561 (tm.tm_mon > 1 && /* Leap day this year */ 562 !((tm.tm_year - 72) & 3)) + 563 tm.tm_mday - 1) * 24) + /* Day of month */ 564 tm.tm_hour) * 60) + 565 tm.tm_min) * 60) + tm.tm_sec; 566 567 /* 568 * This guess could be wrong because of leap seconds or other 569 * weirdness we don't know about that the system does. For 570 * now, we're just going to accept the guess, but at some point 571 * it might be nice to do a successive approximation here to get 572 * an exact value. Even if the error is small, if the server 573 * is restarted frequently (and thus the lease database is 574 * reread), the error could accumulate into something 575 * significant. 576 */ 577 return (guess); 578 } 579