| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: conf.c,v 1.5 1999/10/22 22:46:44 mdw Exp $ |
| 4 | * |
| 5 | * Configuration parsing |
| 6 | * |
| 7 | * (c) 1999 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of the `fw' port forwarder. |
| 13 | * |
| 14 | * `fw' is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * `fw' is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with `fw'; if not, write to the Free Software Foundation, |
| 26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: conf.c,v $ |
| 32 | * Revision 1.5 1999/10/22 22:46:44 mdw |
| 33 | * Improve documentation for conf_enum. |
| 34 | * |
| 35 | * Revision 1.4 1999/10/15 21:12:36 mdw |
| 36 | * Remove redundant debugging code. |
| 37 | * |
| 38 | * Revision 1.3 1999/08/19 18:32:48 mdw |
| 39 | * Improve lexical analysis. In particular, `chmod' patterns don't have to |
| 40 | * be quoted any more. |
| 41 | * |
| 42 | * Revision 1.2 1999/07/26 23:28:39 mdw |
| 43 | * Major reconstruction work for new design. |
| 44 | * |
| 45 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
| 46 | * Initial revision. |
| 47 | * |
| 48 | */ |
| 49 | |
| 50 | /*----- Header files ------------------------------------------------------*/ |
| 51 | |
| 52 | #include "config.h" |
| 53 | |
| 54 | #include <ctype.h> |
| 55 | #include <errno.h> |
| 56 | #include <stdarg.h> |
| 57 | #include <stdio.h> |
| 58 | #include <stdlib.h> |
| 59 | #include <string.h> |
| 60 | |
| 61 | #include <mLib/dstr.h> |
| 62 | #include <mLib/quis.h> |
| 63 | #include <mLib/report.h> |
| 64 | |
| 65 | #include "conf.h" |
| 66 | #include "scan.h" |
| 67 | #include "source.h" |
| 68 | #include "target.h" |
| 69 | |
| 70 | #include "exec.h" |
| 71 | #include "file.h" |
| 72 | #include "socket.h" |
| 73 | |
| 74 | /*----- Source and target tables ------------------------------------------*/ |
| 75 | |
| 76 | static source_ops *sources[] = { &xsource_ops, &fsource_ops, &ssource_ops }; |
| 77 | static target_ops *targets[] = { &xtarget_ops, &ftarget_ops, &starget_ops }; |
| 78 | |
| 79 | static const char *notword = 0; |
| 80 | static const char *notdelim = 0; |
| 81 | |
| 82 | /*----- Main code ---------------------------------------------------------*/ |
| 83 | |
| 84 | /* --- @undelim@ --- * |
| 85 | * |
| 86 | * Arguments: @const char *d, dd@ = pointer to characters to escape |
| 87 | * |
| 88 | * Returns: --- |
| 89 | * |
| 90 | * Use: Modifies the tokenizer. Characters in the first list will |
| 91 | * always be considered to begin a word. Characters in the |
| 92 | * second list will always be allowed to continue a word. |
| 93 | */ |
| 94 | |
| 95 | void undelim(const char *d, const char *dd) { notword = d; notdelim = dd; } |
| 96 | |
| 97 | /* --- @token@ --- * |
| 98 | * |
| 99 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 100 | * |
| 101 | * Returns: Type of token scanned. |
| 102 | * |
| 103 | * Use: Reads the next token from the character scanner. |
| 104 | */ |
| 105 | |
| 106 | int token(scanner *sc) |
| 107 | { |
| 108 | #define SELFDELIM \ |
| 109 | '{': case '}': case '/': case ',': \ |
| 110 | case '=': case ':': case ';': \ |
| 111 | case '.': case '[': case ']' |
| 112 | |
| 113 | int ch; |
| 114 | |
| 115 | DRESET(&sc->d); |
| 116 | |
| 117 | /* --- Main tokenization --- */ |
| 118 | |
| 119 | for (;;) { |
| 120 | ch = scan(sc); |
| 121 | |
| 122 | /* --- Deal with pushed-back tokens --- */ |
| 123 | |
| 124 | if (sc->head->tok) { |
| 125 | dstr_puts(&sc->d, sc->head->tok); |
| 126 | free(sc->head->tok); |
| 127 | sc->head->tok = 0; |
| 128 | sc->t = sc->head->t; |
| 129 | goto done; |
| 130 | } |
| 131 | |
| 132 | else if (isspace((unsigned char)ch)) |
| 133 | ; |
| 134 | else switch (ch) { |
| 135 | |
| 136 | /* --- End of file --- */ |
| 137 | |
| 138 | case EOF: |
| 139 | sc->t = CTOK_EOF; |
| 140 | goto done; |
| 141 | |
| 142 | /* --- Comment character --- */ |
| 143 | |
| 144 | case '#': |
| 145 | do ch = scan(sc); while (ch != EOF && ch != '\n'); |
| 146 | break; |
| 147 | |
| 148 | /* --- Various self-delimiting characters --- */ |
| 149 | |
| 150 | case SELFDELIM: |
| 151 | if (!notword || strchr(notword, ch) == 0) { |
| 152 | dstr_putc(&sc->d, ch); |
| 153 | dstr_putz(&sc->d); |
| 154 | sc->t = ch; |
| 155 | goto done; |
| 156 | } |
| 157 | |
| 158 | /* --- Bare words --- * |
| 159 | * |
| 160 | * These aren't as bare any more. You can now backslash-escape |
| 161 | * individual characters, and enclose sections in double-quotes. |
| 162 | */ |
| 163 | |
| 164 | default: { |
| 165 | int q = 0; |
| 166 | |
| 167 | for (;;) { |
| 168 | switch (ch) { |
| 169 | case EOF: |
| 170 | goto word; |
| 171 | case '\\': |
| 172 | ch = scan(sc); |
| 173 | if (ch == EOF) |
| 174 | goto word; |
| 175 | DPUTC(&sc->d, ch); |
| 176 | break; |
| 177 | case '\"': |
| 178 | q = !q; |
| 179 | break; |
| 180 | case SELFDELIM: |
| 181 | if (q || (notdelim && strchr(notdelim, ch))) |
| 182 | goto insert; |
| 183 | goto word; |
| 184 | default: |
| 185 | if (!q && isspace((unsigned char)(ch))) |
| 186 | goto word; |
| 187 | insert: |
| 188 | DPUTC(&sc->d, ch); |
| 189 | break; |
| 190 | } |
| 191 | ch = scan(sc); |
| 192 | } |
| 193 | word: |
| 194 | unscan(sc, ch); |
| 195 | DPUTZ(&sc->d); |
| 196 | sc->t = CTOK_WORD; |
| 197 | goto done; |
| 198 | } |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | done: |
| 203 | return (sc->t); |
| 204 | } |
| 205 | |
| 206 | /* --- @pushback@ --- * |
| 207 | * |
| 208 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 209 | * |
| 210 | * Returns: --- |
| 211 | * |
| 212 | * Use: Pushes the current token back. This is normally a precursor |
| 213 | * to pushing a new scanner source. |
| 214 | */ |
| 215 | |
| 216 | static void pushback(scanner *sc) |
| 217 | { |
| 218 | sc->head->tok = xstrdup(sc->d.buf); |
| 219 | sc->head->t = sc->t; |
| 220 | } |
| 221 | |
| 222 | /* --- @error@ --- * |
| 223 | * |
| 224 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 225 | * @const char *msg@ = message skeleton string |
| 226 | * @...@ = extra arguments for the skeleton |
| 227 | * |
| 228 | * Returns: Doesn't |
| 229 | * |
| 230 | * Use: Reports an error at the current scanner location. |
| 231 | */ |
| 232 | |
| 233 | void error(scanner *sc, const char *msg, ...) |
| 234 | { |
| 235 | va_list ap; |
| 236 | va_start(ap, msg); |
| 237 | fprintf(stderr, "%s: %s:%i: ", QUIS, sc->head->src, sc->head->line); |
| 238 | vfprintf(stderr, msg, ap); |
| 239 | fputc('\n', stderr); |
| 240 | exit(1); |
| 241 | } |
| 242 | |
| 243 | /* --- @conf_enum@ --- * |
| 244 | * |
| 245 | * Arguments: @scanner *sc@ = pointer to a scanner object |
| 246 | * @const char *list@ = comma-separated things to allow |
| 247 | * @unsigned f@ = flags for the search |
| 248 | * @const char *err@ = error message if not found |
| 249 | * |
| 250 | * Returns: Index into list, zero-based, or @-1@. |
| 251 | * |
| 252 | * Use: Checks whether the current token is a string which matches |
| 253 | * one of the comma-separated items given. The return value is |
| 254 | * the index (zero-based) of the matched string in the list. |
| 255 | * |
| 256 | * The flags control the behaviour if no exact match is found. |
| 257 | * If @ENUM_ABBREV@ is set, and the current token is a left |
| 258 | * substring of exactly one of the possibilities, then that one |
| 259 | * is chosen. If @ENUM_NONE@ is set, the value @-1@ is |
| 260 | * returned; otherwise an error is reported and the program is |
| 261 | * terminated. |
| 262 | */ |
| 263 | |
| 264 | int conf_enum(scanner *sc, const char *list, unsigned f, const char *err) |
| 265 | { |
| 266 | const char *p, *q; |
| 267 | int chosen = -1; |
| 268 | int ok; |
| 269 | int index; |
| 270 | |
| 271 | /* --- Make sure it's a string --- */ |
| 272 | |
| 273 | if (sc->t != CTOK_WORD) |
| 274 | error(sc, "parse error, expected %s", err); |
| 275 | |
| 276 | /* --- Grind through the list --- */ |
| 277 | |
| 278 | q = sc->d.buf; |
| 279 | ok = 1; |
| 280 | index = 0; |
| 281 | p = list; |
| 282 | for (;;) { |
| 283 | switch (*p) { |
| 284 | case 0: |
| 285 | if (ok && !*q) { |
| 286 | token(sc); |
| 287 | return (index); |
| 288 | } else if (chosen != -1) { |
| 289 | token(sc); |
| 290 | return (chosen); |
| 291 | } |
| 292 | else if (f & ENUM_NONE) |
| 293 | return (-1); |
| 294 | else |
| 295 | error(sc, "unknown %s `%s'", err, sc->d.buf); |
| 296 | break; |
| 297 | case ',': |
| 298 | if (ok && !*q) { |
| 299 | token(sc); |
| 300 | return (index); |
| 301 | } |
| 302 | ok = 1; |
| 303 | q = sc->d.buf; |
| 304 | index++; |
| 305 | break; |
| 306 | default: |
| 307 | if (!ok) |
| 308 | break; |
| 309 | if ((f & ENUM_ABBREV) && !*q) { |
| 310 | if (chosen != -1) |
| 311 | error(sc, "ambiguous %s `%s'", err, sc->d.buf); |
| 312 | chosen = index; |
| 313 | ok = 0; |
| 314 | } |
| 315 | if (*p == *q) |
| 316 | q++; |
| 317 | else |
| 318 | ok = 0; |
| 319 | break; |
| 320 | } |
| 321 | p++; |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | /* --- @conf_prefix@ --- * |
| 326 | * |
| 327 | * Arguments: @scanner *sc@ = pointer to a scanner object |
| 328 | * @const char *p@ = pointer to prefix string to check |
| 329 | * |
| 330 | * Returns: Nonzero if the prefix matches. |
| 331 | * |
| 332 | * Use: If the current token is a word matching the given prefix |
| 333 | * string, then it and an optional `.' character are removed and |
| 334 | * a nonzero result is returned. Otherwise the current token is |
| 335 | * left as it is, and zero is returned. |
| 336 | * |
| 337 | * Typical options parsing code would remove an expected prefix, |
| 338 | * scan an option anyway (since qualifying prefixes are |
| 339 | * optional) and if a match is found, claim the option. If no |
| 340 | * match is found, and a prefix was stripped, then an error |
| 341 | * should be reported. |
| 342 | */ |
| 343 | |
| 344 | int conf_prefix(scanner *sc, const char *p) |
| 345 | { |
| 346 | if (sc->t == CTOK_WORD && strcmp(p, sc->d.buf) == 0) { |
| 347 | token(sc); |
| 348 | if (sc->t == '.') |
| 349 | token(sc); |
| 350 | return (1); |
| 351 | } |
| 352 | return (0); |
| 353 | } |
| 354 | |
| 355 | /* --- @conf_name@ --- * |
| 356 | * |
| 357 | * Arguments: @scanner *sc@ = pointer to scanner |
| 358 | * @char delim@ = delimiter character to look for |
| 359 | * @dstr *d@ = pointer to dynamic string for output |
| 360 | * |
| 361 | * Returns: --- |
| 362 | * |
| 363 | * Use: Reads in a compound name consisting of words separated by |
| 364 | * delimiters. Leading and trailing delimiters are permitted, |
| 365 | * although they'll probably cause confusion if used. The name |
| 366 | * may be enclosed in square brackets if that helps at all. |
| 367 | * |
| 368 | * Examples of compound names are filenames (delimited by `/') |
| 369 | * and IP addresses (delimited by `.'). |
| 370 | */ |
| 371 | |
| 372 | void conf_name(scanner *sc, char delim, dstr *d) |
| 373 | { |
| 374 | unsigned f = 0; |
| 375 | enum { |
| 376 | f_ok = 1, |
| 377 | f_bra = 2 |
| 378 | }; |
| 379 | |
| 380 | /* --- Read an optional opening bracket --- */ |
| 381 | |
| 382 | if (sc->t == '[') { |
| 383 | token(sc); |
| 384 | f |= f_bra; |
| 385 | } |
| 386 | |
| 387 | /* --- Do the main reading sequence --- */ |
| 388 | |
| 389 | do { |
| 390 | if (sc->t == delim) { |
| 391 | DPUTC(d, delim); |
| 392 | f |= f_ok; |
| 393 | token(sc); |
| 394 | } |
| 395 | if (sc->t == CTOK_WORD) { |
| 396 | DPUTD(d, &sc->d); |
| 397 | f |= f_ok; |
| 398 | token(sc); |
| 399 | } |
| 400 | } while (sc->t == delim); |
| 401 | |
| 402 | /* --- Check that the string was OK --- */ |
| 403 | |
| 404 | if (!(f & f_ok)) |
| 405 | error(sc, "parse error, name expected"); |
| 406 | |
| 407 | /* --- Read a closing bracket --- */ |
| 408 | |
| 409 | if (f & f_bra) { |
| 410 | if (sc->t == ']') |
| 411 | token(sc); |
| 412 | else |
| 413 | error(sc, "parse error, missing `]'"); |
| 414 | } |
| 415 | DPUTZ(d); |
| 416 | } |
| 417 | |
| 418 | /* --- @conf_parse@ --- * |
| 419 | * |
| 420 | * Arguments: @scanner *sc@ = pointer to scanner definition |
| 421 | * |
| 422 | * Returns: --- |
| 423 | * |
| 424 | * Use: Parses a configuration file from the scanner. |
| 425 | */ |
| 426 | |
| 427 | void conf_parse(scanner *sc) |
| 428 | { |
| 429 | token(sc); |
| 430 | |
| 431 | for (;;) { |
| 432 | if (sc->t == CTOK_EOF) |
| 433 | break; |
| 434 | if (sc->t != CTOK_WORD) |
| 435 | error(sc, "parse error, keyword expected"); |
| 436 | |
| 437 | /* --- Handle a forwarding request --- */ |
| 438 | |
| 439 | if (strcmp(sc->d.buf, "forward") == 0 || |
| 440 | strcmp(sc->d.buf, "fw") == 0 || |
| 441 | strcmp(sc->d.buf, "from") == 0) { |
| 442 | source *s; |
| 443 | target *t; |
| 444 | |
| 445 | token(sc); |
| 446 | |
| 447 | /* --- Read a source description --- */ |
| 448 | |
| 449 | { |
| 450 | source_ops **sops; |
| 451 | |
| 452 | /* --- Try to find a source type which understands --- */ |
| 453 | |
| 454 | s = 0; |
| 455 | for (sops = sources; *sops; sops++) { |
| 456 | if ((s = (*sops)->read(sc)) != 0) |
| 457 | goto found_source; |
| 458 | } |
| 459 | error(sc, "unknown source name `%s'", sc->d.buf); |
| 460 | |
| 461 | /* --- Read any source-specific options --- */ |
| 462 | |
| 463 | found_source: |
| 464 | if (sc->t == '{') { |
| 465 | token(sc); |
| 466 | while (sc->t == CTOK_WORD) { |
| 467 | if (!s->ops->option || !s->ops->option(s, sc)) { |
| 468 | error(sc, "unknown %s source option `%s'", |
| 469 | s->ops->name, sc->d.buf); |
| 470 | } |
| 471 | if (sc->t == ';') |
| 472 | token(sc); |
| 473 | } |
| 474 | if (sc->t != '}') |
| 475 | error(sc, "parse error, missing `}'"); |
| 476 | token(sc); |
| 477 | } |
| 478 | } |
| 479 | |
| 480 | /* --- Read a destination description --- */ |
| 481 | |
| 482 | if (sc->t == CTOK_WORD && (strcmp(sc->d.buf, "to") == 0 || |
| 483 | strcmp(sc->d.buf, "->") == 0)) |
| 484 | token(sc); |
| 485 | |
| 486 | { |
| 487 | target_ops **tops; |
| 488 | |
| 489 | /* --- Try to find a target which understands --- */ |
| 490 | |
| 491 | t = 0; |
| 492 | for (tops = targets; *tops; tops++) { |
| 493 | if ((t = (*tops)->read(sc)) != 0) |
| 494 | goto found_target; |
| 495 | } |
| 496 | error(sc, "unknown target name `%s'", sc->d.buf); |
| 497 | |
| 498 | /* --- Read any target-specific options --- */ |
| 499 | |
| 500 | found_target: |
| 501 | if (sc->t == '{') { |
| 502 | token(sc); |
| 503 | while (sc->t == CTOK_WORD) { |
| 504 | if (!t->ops->option || !t->ops->option(t, sc)) { |
| 505 | error(sc, "unknown %s target option `%s'", |
| 506 | t->ops->name, sc->d.buf); |
| 507 | } |
| 508 | if (sc->t == ';') |
| 509 | token(sc); |
| 510 | } |
| 511 | if (sc->t != '}') |
| 512 | error(sc, "parse error, `}' expected"); |
| 513 | token(sc); |
| 514 | } |
| 515 | } |
| 516 | |
| 517 | /* --- Combine the source and target --- */ |
| 518 | |
| 519 | s->ops->attach(s, sc, t); |
| 520 | } |
| 521 | |
| 522 | /* --- Include configuration from a file --- * |
| 523 | * |
| 524 | * Slightly tricky. Scan the optional semicolon from the including |
| 525 | * stream, not the included one. |
| 526 | */ |
| 527 | |
| 528 | else if (strcmp(sc->d.buf, "include") == 0) { |
| 529 | FILE *fp; |
| 530 | dstr d = DSTR_INIT; |
| 531 | |
| 532 | token(sc); |
| 533 | conf_name(sc, '/', &d); |
| 534 | if ((fp = fopen(d.buf, "r")) == 0) |
| 535 | error(sc, "can't include `%s': %s", d.buf, strerror(errno)); |
| 536 | if (sc->t == ';') |
| 537 | token(sc); |
| 538 | pushback(sc); |
| 539 | scan_push(sc, scan_file(fp, xstrdup(d.buf), SCF_FREENAME)); |
| 540 | token(sc); |
| 541 | dstr_destroy(&d); |
| 542 | continue; /* Don't parse a trailing `;' */ |
| 543 | } |
| 544 | |
| 545 | /* --- Other configuration is handled elsewhere --- */ |
| 546 | |
| 547 | else { |
| 548 | |
| 549 | /* --- First try among the sources --- */ |
| 550 | |
| 551 | { |
| 552 | source_ops **sops; |
| 553 | |
| 554 | for (sops = sources; *sops; sops++) { |
| 555 | if ((*sops)->option && (*sops)->option(0, sc)) |
| 556 | goto found_option; |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | /* --- Then try among the targets --- */ |
| 561 | |
| 562 | { |
| 563 | target_ops **tops; |
| 564 | |
| 565 | for (tops = targets; *tops; tops++) { |
| 566 | if ((*tops)->option && (*tops)->option(0, sc)) |
| 567 | goto found_option; |
| 568 | } |
| 569 | } |
| 570 | |
| 571 | /* --- Nobody wants the option --- */ |
| 572 | |
| 573 | error(sc, "unknown global option or prefix `%s'", sc->d.buf); |
| 574 | |
| 575 | found_option:; |
| 576 | } |
| 577 | |
| 578 | if (sc->t == ';') |
| 579 | token(sc); |
| 580 | } |
| 581 | } |
| 582 | |
| 583 | /*----- That's all, folks -------------------------------------------------*/ |