1 /* $OpenBSD: unifdef.c,v 1.11 2003/06/30 18:37:48 avsm Exp $ */ 2 /* 3 * Copyright (c) 2002, 2003 Tony Finch <dot@dotat.at> 4 * Copyright (c) 1985, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Dave Yost. Support for #if and #elif was added by Tony Finch. 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 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1985, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 40 #if 0 41 static char sccsid[] = "@(#)unifdef.c 8.1 (Berkeley) 6/6/93"; 42 #endif 43 static const char rcsid[] = "$OpenBSD: unifdef.c,v 1.11 2003/06/30 18:37:48 avsm Exp $"; 44 #endif 45 46 /* 47 * unifdef - remove ifdef'ed lines 48 * 49 * Wishlist: 50 * provide an option which will append the name of the 51 * appropriate symbol after #else's and #endif's 52 * provide an option which will check symbols after 53 * #else's and #endif's to see that they match their 54 * corresponding #ifdef or #ifndef 55 * generate #line directives in place of deleted code 56 * 57 * The first two items above require better buffer handling, which would 58 * also make it possible to handle all "dodgy" directives correctly. 59 */ 60 61 #include <ctype.h> 62 #include <err.h> 63 #include <stdarg.h> 64 #include <stdbool.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 70 /* types of input lines: */ 71 typedef enum { 72 LT_TRUEI, /* a true #if with ignore flag */ 73 LT_FALSEI, /* a false #if with ignore flag */ 74 LT_IF, /* an unknown #if */ 75 LT_TRUE, /* a true #if */ 76 LT_FALSE, /* a false #if */ 77 LT_ELIF, /* an unknown #elif */ 78 LT_ELTRUE, /* a true #elif */ 79 LT_ELFALSE, /* a false #elif */ 80 LT_ELSE, /* #else */ 81 LT_ENDIF, /* #endif */ 82 LT_DODGY, /* flag: directive is not on one line */ 83 LT_DODGY_LAST = LT_DODGY + LT_ENDIF, 84 LT_PLAIN, /* ordinary line */ 85 LT_EOF, /* end of file */ 86 LT_COUNT 87 } Linetype; 88 89 static char const * const linetype_name[] = { 90 "TRUEI", "FALSEI", "IF", "TRUE", "FALSE", 91 "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF", 92 "DODGY TRUEI", "DODGY FALSEI", 93 "DODGY IF", "DODGY TRUE", "DODGY FALSE", 94 "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE", 95 "DODGY ELSE", "DODGY ENDIF", 96 "PLAIN", "EOF" 97 }; 98 99 /* state of #if processing */ 100 typedef enum { 101 IS_OUTSIDE, 102 IS_FALSE_PREFIX, /* false #if followed by false #elifs */ 103 IS_TRUE_PREFIX, /* first non-false #(el)if is true */ 104 IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */ 105 IS_FALSE_MIDDLE, /* a false #elif after a pass state */ 106 IS_TRUE_MIDDLE, /* a true #elif after a pass state */ 107 IS_PASS_ELSE, /* an else after a pass state */ 108 IS_FALSE_ELSE, /* an else after a true state */ 109 IS_TRUE_ELSE, /* an else after only false states */ 110 IS_FALSE_TRAILER, /* #elifs after a true are false */ 111 IS_COUNT 112 } Ifstate; 113 114 static char const * const ifstate_name[] = { 115 "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX", 116 "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE", 117 "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE", 118 "FALSE_TRAILER" 119 }; 120 121 /* state of comment parser */ 122 typedef enum { 123 NO_COMMENT = false, /* outside a comment */ 124 C_COMMENT, /* in a comment like this one */ 125 CXX_COMMENT, /* between // and end of line */ 126 STARTING_COMMENT, /* just after slash-backslash-newline */ 127 FINISHING_COMMENT /* star-backslash-newline in a C comment */ 128 } Comment_state; 129 130 static char const * const comment_name[] = { 131 "NO", "C", "CXX", "STARTING", "FINISHING" 132 }; 133 134 /* state of preprocessor line parser */ 135 typedef enum { 136 LS_START, /* only space and comments on this line */ 137 LS_HASH, /* only space, comments, and a hash */ 138 LS_DIRTY /* this line can't be a preprocessor line */ 139 } Line_state; 140 141 static char const * const linestate_name[] = { 142 "START", "HASH", "DIRTY" 143 }; 144 145 /* 146 * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1 147 */ 148 #define MAXDEPTH 64 /* maximum #if nesting */ 149 #define MAXLINE 4096 /* maximum length of line */ 150 #define MAXSYMS 4096 /* maximum number of symbols */ 151 152 /* 153 * Sometimes when editing a keyword the replacement text is longer, so 154 * we leave some space at the end of the tline buffer to accommodate this. 155 */ 156 #define EDITSLOP 10 157 158 /* 159 * Globals. 160 */ 161 162 static bool complement; /* -c: do the complement */ 163 static bool debugging; /* -d: debugging reports */ 164 static bool iocccok; /* -e: fewer IOCCC errors */ 165 static bool killconsts; /* -k: eval constant #ifs */ 166 static bool lnblank; /* -l: blank deleted lines */ 167 static bool symlist; /* -s: output symbol list */ 168 static bool text; /* -t: this is a text file */ 169 170 static const char *symname[MAXSYMS]; /* symbol name */ 171 static const char *value[MAXSYMS]; /* -Dsym=value */ 172 static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */ 173 static int nsyms; /* number of symbols */ 174 175 static FILE *input; /* input file pointer */ 176 static const char *filename; /* input file name */ 177 static int linenum; /* current line number */ 178 179 static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */ 180 static char *keyword; /* used for editing #elif's */ 181 182 static Comment_state incomment; /* comment parser state */ 183 static Line_state linestate; /* #if line parser state */ 184 static Ifstate ifstate[MAXDEPTH]; /* #if processor state */ 185 static bool ignoring[MAXDEPTH]; /* ignore comments state */ 186 static int stifline[MAXDEPTH]; /* start of current #if */ 187 static int depth; /* current #if nesting */ 188 static bool keepthis; /* don't delete constant #if */ 189 190 static int exitstat; /* program exit status */ 191 192 static void addsym(bool, bool, char *); 193 static void debug(const char *, ...); 194 static void error(const char *); 195 static int findsym(const char *); 196 static void flushline(bool); 197 static Linetype getline(void); 198 static Linetype ifeval(const char **); 199 static void ignoreoff(void); 200 static void ignoreon(void); 201 static void keywordedit(const char *); 202 static void nest(void); 203 static void process(void); 204 static const char *skipcomment(const char *); 205 static const char *skipsym(const char *); 206 static void state(Ifstate); 207 static int strlcmp(const char *, const char *, size_t); 208 static void usage(void); 209 210 #define endsym(c) (!isalpha((unsigned char)c) && !isdigit((unsigned char)c) && c != '_') 211 212 /* 213 * The main program. 214 */ 215 int 216 main(int argc, char *argv[]) 217 { 218 int opt; 219 220 while ((opt = getopt(argc, argv, "i:D:U:I:cdeklst")) != -1) 221 switch (opt) { 222 case 'i': /* treat stuff controlled by these symbols as text */ 223 /* 224 * For strict backwards-compatibility the U or D 225 * should be immediately after the -i but it doesn't 226 * matter much if we relax that requirement. 227 */ 228 opt = *optarg++; 229 if (opt == 'D') 230 addsym(true, true, optarg); 231 else if (opt == 'U') 232 addsym(true, false, optarg); 233 else 234 usage(); 235 break; 236 case 'D': /* define a symbol */ 237 addsym(false, true, optarg); 238 break; 239 case 'U': /* undef a symbol */ 240 addsym(false, false, optarg); 241 break; 242 case 'I': 243 /* no-op for compatibility with cpp */ 244 break; 245 case 'c': /* treat -D as -U and vice versa */ 246 complement = true; 247 break; 248 case 'd': 249 debugging = true; 250 break; 251 case 'e': /* fewer errors from dodgy lines */ 252 iocccok = true; 253 break; 254 case 'k': /* process constant #ifs */ 255 killconsts = true; 256 break; 257 case 'l': /* blank deleted lines instead of omitting them */ 258 lnblank = true; 259 break; 260 case 's': /* only output list of symbols that control #ifs */ 261 symlist = true; 262 break; 263 case 't': /* don't parse C comments */ 264 text = true; 265 break; 266 default: 267 usage(); 268 } 269 argc -= optind; 270 argv += optind; 271 if (nsyms == 0 && !symlist) { 272 warnx("must -D or -U at least one symbol"); 273 usage(); 274 } 275 if (argc > 1) { 276 errx(2, "can only do one file"); 277 } else if (argc == 1 && strcmp(*argv, "-") != 0) { 278 filename = *argv; 279 if ((input = fopen(filename, "r")) != NULL) { 280 process(); 281 (void) fclose(input); 282 } else 283 err(2, "can't open %s", *argv); 284 } else { 285 filename = "[stdin]"; 286 input = stdin; 287 process(); 288 } 289 290 exit(exitstat); 291 } 292 293 static void 294 usage(void) 295 { 296 fprintf(stderr, "usage: unifdef [-cdeklst]" 297 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n"); 298 exit(2); 299 } 300 301 /* 302 * A state transition function alters the global #if processing state 303 * in a particular way. The table below is indexed by the current 304 * processing state and the type of the current line. A NULL entry 305 * indicates that processing is complete. 306 * 307 * Nesting is handled by keeping a stack of states; some transition 308 * functions increase or decrease the depth. They also maintain the 309 * ignore state on a stack. In some complicated cases they have to 310 * alter the preprocessor directive, as follows. 311 * 312 * When we have processed a group that starts off with a known-false 313 * #if/#elif sequence (which has therefore been deleted) followed by a 314 * #elif that we don't understand and therefore must keep, we edit the 315 * latter into a #if to keep the nesting correct. 316 * 317 * When we find a true #elif in a group, the following block will 318 * always be kept and the rest of the sequence after the next #elif or 319 * #else will be discarded. We edit the #elif into a #else and the 320 * following directive to #endif since this has the desired behaviour. 321 * 322 * "Dodgy" directives are split across multiple lines, the most common 323 * example being a multi-line comment hanging off the right of the 324 * directive. We can handle them correctly only if there is no change 325 * from printing to dropping (or vice versa) caused by that directive. 326 * If the directive is the first of a group we have a choice between 327 * failing with an error, or passing it through unchanged instead of 328 * evaluating it. The latter is not the default to avoid questions from 329 * users about unifdef unexpectedly leaving behind preprocessor directives. 330 */ 331 typedef void state_fn(void); 332 333 /* report an error */ 334 static void 335 Eelif(void) 336 { 337 error("Inappropriate #elif"); 338 } 339 340 static void 341 Eelse(void) 342 { 343 error("Inappropriate #else"); 344 } 345 346 static void 347 Eendif(void) 348 { 349 error("Inappropriate #endif"); 350 } 351 352 static void 353 Eeof(void) 354 { 355 error("Premature EOF"); 356 } 357 358 static void 359 Eioccc(void) 360 { 361 error("Obfuscated preprocessor control line"); 362 } 363 364 /* plain line handling */ 365 static void 366 print(void) 367 { 368 flushline(true); 369 } 370 371 static void 372 drop(void) 373 { 374 flushline(false); 375 } 376 377 /* output lacks group's start line */ 378 static void 379 Strue(void) 380 { 381 drop(); 382 ignoreoff(); 383 state(IS_TRUE_PREFIX); 384 } 385 386 static void 387 Sfalse(void) 388 { 389 drop(); 390 ignoreoff(); 391 state(IS_FALSE_PREFIX); 392 } 393 394 static void 395 Selse(void) 396 { 397 drop(); 398 state(IS_TRUE_ELSE); 399 } 400 401 /* print/pass this block */ 402 static void 403 Pelif(void) 404 { 405 print(); 406 ignoreoff(); 407 state(IS_PASS_MIDDLE); 408 } 409 410 static void 411 Pelse(void) 412 { 413 print(); 414 state(IS_PASS_ELSE); 415 } 416 417 static void 418 Pendif(void) 419 { 420 print(); 421 --depth; 422 } 423 424 /* discard this block */ 425 static void 426 Dfalse(void) 427 { 428 drop(); 429 ignoreoff(); 430 state(IS_FALSE_TRAILER); 431 } 432 433 static void 434 Delif(void) 435 { 436 drop(); 437 ignoreoff(); 438 state(IS_FALSE_MIDDLE); 439 } 440 441 static void 442 Delse(void) 443 { 444 drop(); 445 state(IS_FALSE_ELSE); 446 } 447 448 static void 449 Dendif(void) 450 { 451 drop(); 452 --depth; 453 } 454 455 /* first line of group */ 456 static void 457 Fdrop(void) 458 { 459 nest(); 460 Dfalse(); 461 } 462 463 static void 464 Fpass(void) 465 { 466 nest(); 467 Pelif(); 468 } 469 470 static void 471 Ftrue(void) 472 { 473 nest(); 474 Strue(); 475 } 476 477 static void 478 Ffalse(void) 479 { 480 nest(); 481 Sfalse(); 482 } 483 484 /* variable pedantry for obfuscated lines */ 485 static void 486 Oiffy(void) 487 { 488 if (iocccok) 489 Fpass(); 490 else 491 Eioccc(); 492 ignoreon(); 493 } 494 495 static void 496 Oif(void) 497 { 498 if (iocccok) 499 Fpass(); 500 else 501 Eioccc(); 502 } 503 504 static void 505 Oelif(void) 506 { 507 if (iocccok) 508 Pelif(); 509 else 510 Eioccc(); 511 } 512 513 /* ignore comments in this block */ 514 static void 515 Idrop(void) 516 { 517 Fdrop(); 518 ignoreon(); 519 } 520 521 static void 522 Itrue(void) 523 { 524 Ftrue(); 525 ignoreon(); 526 } 527 528 static void 529 Ifalse(void) 530 { 531 Ffalse(); 532 ignoreon(); 533 } 534 535 /* edit this line */ 536 static void 537 Mpass (void) 538 { 539 strncpy(keyword, "if ", 4); 540 Pelif(); 541 } 542 543 static void 544 Mtrue (void) 545 { 546 keywordedit("else\n"); 547 state(IS_TRUE_MIDDLE); 548 } 549 550 static void 551 Melif (void) 552 { 553 keywordedit("endif\n"); 554 state(IS_FALSE_TRAILER); 555 } 556 557 static void 558 Melse (void) 559 { 560 keywordedit("endif\n"); 561 state(IS_FALSE_ELSE); 562 } 563 564 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = { 565 /* IS_OUTSIDE */ 566 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif, 567 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif, 568 print, NULL }, 569 /* IS_FALSE_PREFIX */ 570 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif, 571 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc, 572 drop, Eeof }, 573 /* IS_TRUE_PREFIX */ 574 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif, 575 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 576 print, Eeof }, 577 /* IS_PASS_MIDDLE */ 578 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif, 579 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif, 580 print, Eeof }, 581 /* IS_FALSE_MIDDLE */ 582 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif, 583 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 584 drop, Eeof }, 585 /* IS_TRUE_MIDDLE */ 586 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif, 587 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif, 588 print, Eeof }, 589 /* IS_PASS_ELSE */ 590 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif, 591 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif, 592 print, Eeof }, 593 /* IS_FALSE_ELSE */ 594 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif, 595 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc, 596 drop, Eeof }, 597 /* IS_TRUE_ELSE */ 598 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif, 599 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc, 600 print, Eeof }, 601 /* IS_FALSE_TRAILER */ 602 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif, 603 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc, 604 drop, Eeof } 605 /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF 606 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY) 607 PLAIN EOF */ 608 }; 609 610 /* 611 * State machine utility functions 612 */ 613 static void 614 ignoreoff(void) 615 { 616 ignoring[depth] = ignoring[depth-1]; 617 } 618 619 static void 620 ignoreon(void) 621 { 622 ignoring[depth] = true; 623 } 624 625 static void 626 keywordedit(const char *replacement) 627 { 628 strlcpy(keyword, replacement, tline + sizeof(tline) - keyword); 629 print(); 630 } 631 632 static void 633 nest(void) 634 { 635 depth += 1; 636 if (depth >= MAXDEPTH) 637 error("Too many levels of nesting"); 638 stifline[depth] = linenum; 639 } 640 641 static void 642 state(Ifstate is) 643 { 644 ifstate[depth] = is; 645 } 646 647 /* 648 * Write a line to the output or not, according to command line options. 649 */ 650 static void 651 flushline(bool keep) 652 { 653 if (symlist) 654 return; 655 if (keep ^ complement) 656 fputs(tline, stdout); 657 else { 658 if (lnblank) 659 putc('\n', stdout); 660 exitstat = 1; 661 } 662 } 663 664 /* 665 * The driver for the state machine. 666 */ 667 static void 668 process(void) 669 { 670 Linetype lineval; 671 state_fn *trans; 672 673 for (;;) { 674 linenum++; 675 lineval = getline(); 676 trans = trans_table[ifstate[depth]][lineval]; 677 if (trans == NULL) 678 break; 679 trans(); 680 debug("process %s -> %s depth %d", 681 linetype_name[lineval], 682 ifstate_name[ifstate[depth]], depth); 683 } 684 if (incomment) 685 error("EOF in comment"); 686 } 687 688 /* 689 * Parse a line and determine its type. We keep the preprocessor line 690 * parser state between calls in a global variable. 691 */ 692 static Linetype 693 getline(void) 694 { 695 const char *cp; 696 int cursym; 697 int kwlen; 698 Linetype retval; 699 Comment_state wascomment; 700 701 if (fgets(tline, MAXLINE, input) == NULL) 702 return (LT_EOF); 703 retval = LT_PLAIN; 704 wascomment = incomment; 705 cp = skipcomment(tline); 706 if (linestate == LS_START) { 707 if (*cp == '#') { 708 linestate = LS_HASH; 709 cp = skipcomment(cp + 1); 710 } else if (*cp != '\0') 711 linestate = LS_DIRTY; 712 } 713 if (!incomment && linestate == LS_HASH) { 714 keyword = tline + (cp - tline); 715 cp = skipsym(cp); 716 kwlen = cp - keyword; 717 /* no way can we deal with a continuation inside a keyword */ 718 if (strncmp(cp, "\\\n", 2) == 0) 719 Eioccc(); 720 if (strlcmp("ifdef", keyword, kwlen) == 0 || 721 strlcmp("ifndef", keyword, kwlen) == 0) { 722 cp = skipcomment(cp); 723 if ((cursym = findsym(cp)) < 0) 724 retval = LT_IF; 725 else { 726 retval = (keyword[2] == 'n') 727 ? LT_FALSE : LT_TRUE; 728 if (value[cursym] == NULL) 729 retval = (retval == LT_TRUE) 730 ? LT_FALSE : LT_TRUE; 731 if (ignore[cursym]) 732 retval = (retval == LT_TRUE) 733 ? LT_TRUEI : LT_FALSEI; 734 } 735 cp = skipsym(cp); 736 } else if (strlcmp("if", keyword, kwlen) == 0) 737 retval = ifeval(&cp); 738 else if (strlcmp("elif", keyword, kwlen) == 0) 739 retval = ifeval(&cp) - LT_IF + LT_ELIF; 740 else if (strlcmp("else", keyword, kwlen) == 0) 741 retval = LT_ELSE; 742 else if (strlcmp("endif", keyword, kwlen) == 0) 743 retval = LT_ENDIF; 744 else { 745 linestate = LS_DIRTY; 746 retval = LT_PLAIN; 747 } 748 cp = skipcomment(cp); 749 if (*cp != '\0') { 750 linestate = LS_DIRTY; 751 if (retval == LT_TRUE || retval == LT_FALSE || 752 retval == LT_TRUEI || retval == LT_FALSEI) 753 retval = LT_IF; 754 if (retval == LT_ELTRUE || retval == LT_ELFALSE) 755 retval = LT_ELIF; 756 } 757 if (retval != LT_PLAIN && (wascomment || incomment)) { 758 retval += LT_DODGY; 759 if (incomment) 760 linestate = LS_DIRTY; 761 } 762 /* skipcomment should have changed the state */ 763 if (linestate == LS_HASH) 764 abort(); /* bug */ 765 } 766 if (linestate == LS_DIRTY) { 767 while (*cp != '\0') 768 cp = skipcomment(cp + 1); 769 } 770 debug("parser %s comment %s line", 771 comment_name[incomment], linestate_name[linestate]); 772 return (retval); 773 } 774 775 /* 776 * These are the operators that are supported by the expression 777 * evaluator. Note that if support for division is added then we also 778 * need short-circuiting booleans because of divide-by-zero. 779 */ 780 static int 781 op_lt(int a, int b) 782 { 783 return (a < b); 784 } 785 786 static int 787 op_gt(int a, int b) 788 { 789 return (a > b); 790 } 791 792 static int 793 op_le(int a, int b) 794 { 795 return (a <= b); 796 } 797 798 static int 799 op_ge(int a, int b) 800 { 801 return (a >= b); 802 } 803 804 static int 805 op_eq(int a, int b) 806 { 807 return (a == b); 808 } 809 810 static int 811 op_ne(int a, int b) 812 { 813 return (a != b); 814 } 815 816 static int 817 op_or(int a, int b) 818 { 819 return (a || b); 820 } 821 822 static int 823 op_and(int a, int b) 824 { 825 return (a && b); 826 } 827 828 /* 829 * An evaluation function takes three arguments, as follows: (1) a pointer to 830 * an element of the precedence table which lists the operators at the current 831 * level of precedence; (2) a pointer to an integer which will receive the 832 * value of the expression; and (3) a pointer to a char* that points to the 833 * expression to be evaluated and that is updated to the end of the expression 834 * when evaluation is complete. The function returns LT_FALSE if the value of 835 * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the 836 * expression could not be evaluated. 837 */ 838 struct ops; 839 840 typedef Linetype eval_fn(const struct ops *, int *, const char **); 841 842 static eval_fn eval_table, eval_unary; 843 844 /* 845 * The precedence table. Expressions involving binary operators are evaluated 846 * in a table-driven way by eval_table. When it evaluates a subexpression it 847 * calls the inner function with its first argument pointing to the next 848 * element of the table. Innermost expressions have special non-table-driven 849 * handling. 850 */ 851 static const struct ops { 852 eval_fn *inner; 853 struct op { 854 const char *str; 855 int (*fn)(int, int); 856 } op[5]; 857 } eval_ops[] = { 858 { eval_table, { { "||", op_or } } }, 859 { eval_table, { { "&&", op_and } } }, 860 { eval_table, { { "==", op_eq }, 861 { "!=", op_ne } } }, 862 { eval_unary, { { "<=", op_le }, 863 { ">=", op_ge }, 864 { "<", op_lt }, 865 { ">", op_gt } } } 866 }; 867 868 /* 869 * Function for evaluating the innermost parts of expressions, 870 * viz. !expr (expr) defined(symbol) symbol number 871 * We reset the keepthis flag when we find a non-constant subexpression. 872 */ 873 static Linetype 874 eval_unary(const struct ops *ops, int *valp, const char **cpp) 875 { 876 const char *cp; 877 char *ep; 878 int sym; 879 880 cp = skipcomment(*cpp); 881 if (*cp == '!') { 882 debug("eval%d !", ops - eval_ops); 883 cp++; 884 if (eval_unary(ops, valp, &cp) == LT_IF) 885 return (LT_IF); 886 *valp = !*valp; 887 } else if (*cp == '(') { 888 cp++; 889 debug("eval%d (", ops - eval_ops); 890 if (eval_table(eval_ops, valp, &cp) == LT_IF) 891 return (LT_IF); 892 cp = skipcomment(cp); 893 if (*cp++ != ')') 894 return (LT_IF); 895 } else if (isdigit((unsigned char)*cp)) { 896 debug("eval%d number", ops - eval_ops); 897 *valp = strtol(cp, &ep, 0); 898 cp = skipsym(cp); 899 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) { 900 cp = skipcomment(cp+7); 901 debug("eval%d defined", ops - eval_ops); 902 if (*cp++ != '(') 903 return (LT_IF); 904 cp = skipcomment(cp); 905 sym = findsym(cp); 906 if (sym < 0 && !symlist) 907 return (LT_IF); 908 *valp = (value[sym] != NULL); 909 cp = skipsym(cp); 910 cp = skipcomment(cp); 911 if (*cp++ != ')') 912 return (LT_IF); 913 keepthis = false; 914 } else if (!endsym(*cp)) { 915 debug("eval%d symbol", ops - eval_ops); 916 sym = findsym(cp); 917 if (sym < 0 && !symlist) 918 return (LT_IF); 919 if (value[sym] == NULL) 920 *valp = 0; 921 else { 922 *valp = strtol(value[sym], &ep, 0); 923 if (*ep != '\0' || ep == value[sym]) 924 return (LT_IF); 925 } 926 cp = skipsym(cp); 927 keepthis = false; 928 } else 929 return (LT_IF); 930 931 *cpp = cp; 932 debug("eval%d = %d", ops - eval_ops, *valp); 933 return (*valp ? LT_TRUE : LT_FALSE); 934 } 935 936 /* 937 * Table-driven evaluation of binary operators. 938 */ 939 static Linetype 940 eval_table(const struct ops *ops, int *valp, const char **cpp) 941 { 942 const struct op *op; 943 const char *cp; 944 int val; 945 946 debug("eval%d", ops - eval_ops); 947 cp = *cpp; 948 if (ops->inner(ops+1, valp, &cp) == LT_IF) 949 return (LT_IF); 950 for (;;) { 951 cp = skipcomment(cp); 952 for (op = ops->op; op->str != NULL; op++) 953 if (strncmp(cp, op->str, strlen(op->str)) == 0) 954 break; 955 if (op->str == NULL) 956 break; 957 cp += strlen(op->str); 958 debug("eval%d %s", ops - eval_ops, op->str); 959 if (ops->inner(ops+1, &val, &cp) == LT_IF) 960 return (LT_IF); 961 *valp = op->fn(*valp, val); 962 } 963 964 *cpp = cp; 965 debug("eval%d = %d", ops - eval_ops, *valp); 966 return (*valp ? LT_TRUE : LT_FALSE); 967 } 968 969 /* 970 * Evaluate the expression on a #if or #elif line. If we can work out 971 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we 972 * return just a generic LT_IF. 973 */ 974 static Linetype 975 ifeval(const char **cpp) 976 { 977 int ret; 978 int val; 979 980 debug("eval %s", *cpp); 981 keepthis = killconsts ? false : true; 982 ret = eval_table(eval_ops, &val, cpp); 983 return (keepthis ? LT_IF : ret); 984 } 985 986 /* 987 * Skip over comments and stop at the next character position that is 988 * not whitespace. Between calls we keep the comment state in the 989 * global variable incomment, and we also adjust the global variable 990 * linestate when we see a newline. 991 * XXX: doesn't cope with the buffer splitting inside a state transition. 992 */ 993 static const char * 994 skipcomment(const char *cp) 995 { 996 if (text || ignoring[depth]) { 997 for (; isspace((unsigned char)*cp); cp++) 998 if (*cp == '\n') 999 linestate = LS_START; 1000 return (cp); 1001 } 1002 while (*cp != '\0') 1003 if (strncmp(cp, "\\\n", 2) == 0) 1004 cp += 2; 1005 else switch (incomment) { 1006 case NO_COMMENT: 1007 if (strncmp(cp, "/\\\n", 3) == 0) { 1008 incomment = STARTING_COMMENT; 1009 cp += 3; 1010 } else if (strncmp(cp, "/*", 2) == 0) { 1011 incomment = C_COMMENT; 1012 cp += 2; 1013 } else if (strncmp(cp, "//", 2) == 0) { 1014 incomment = CXX_COMMENT; 1015 cp += 2; 1016 } else if (strncmp(cp, "\n", 1) == 0) { 1017 linestate = LS_START; 1018 cp += 1; 1019 } else if (strchr(" \t", *cp) != NULL) { 1020 cp += 1; 1021 } else 1022 return (cp); 1023 continue; 1024 case CXX_COMMENT: 1025 if (strncmp(cp, "\n", 1) == 0) { 1026 incomment = NO_COMMENT; 1027 linestate = LS_START; 1028 } 1029 cp += 1; 1030 continue; 1031 case C_COMMENT: 1032 if (strncmp(cp, "*\\\n", 3) == 0) { 1033 incomment = FINISHING_COMMENT; 1034 cp += 3; 1035 } else if (strncmp(cp, "*/", 2) == 0) { 1036 incomment = NO_COMMENT; 1037 cp += 2; 1038 } else 1039 cp += 1; 1040 continue; 1041 case STARTING_COMMENT: 1042 if (*cp == '*') { 1043 incomment = C_COMMENT; 1044 cp += 1; 1045 } else if (*cp == '/') { 1046 incomment = CXX_COMMENT; 1047 cp += 1; 1048 } else { 1049 incomment = NO_COMMENT; 1050 linestate = LS_DIRTY; 1051 } 1052 continue; 1053 case FINISHING_COMMENT: 1054 if (*cp == '/') { 1055 incomment = NO_COMMENT; 1056 cp += 1; 1057 } else 1058 incomment = C_COMMENT; 1059 continue; 1060 default: 1061 /* bug */ 1062 abort(); 1063 } 1064 return (cp); 1065 } 1066 1067 /* 1068 * Skip over an identifier. 1069 */ 1070 static const char * 1071 skipsym(const char *cp) 1072 { 1073 while (!endsym(*cp)) 1074 ++cp; 1075 return (cp); 1076 } 1077 1078 /* 1079 * Look for the symbol in the symbol table. If is is found, we return 1080 * the symbol table index, else we return -1. 1081 */ 1082 static int 1083 findsym(const char *str) 1084 { 1085 const char *cp; 1086 int symind; 1087 1088 cp = skipsym(str); 1089 if (cp == str) 1090 return (-1); 1091 if (symlist) 1092 printf("%.*s\n", (int)(cp-str), str); 1093 for (symind = 0; symind < nsyms; ++symind) { 1094 if (strlcmp(symname[symind], str, cp-str) == 0) { 1095 debug("findsym %s %s", symname[symind], 1096 value[symind] ? value[symind] : ""); 1097 return (symind); 1098 } 1099 } 1100 return (-1); 1101 } 1102 1103 /* 1104 * Add a symbol to the symbol table. 1105 */ 1106 static void 1107 addsym(bool ignorethis, bool definethis, char *sym) 1108 { 1109 int symind; 1110 char *val; 1111 1112 symind = findsym(sym); 1113 if (symind < 0) { 1114 if (nsyms >= MAXSYMS) 1115 errx(2, "too many symbols"); 1116 symind = nsyms++; 1117 } 1118 symname[symind] = sym; 1119 ignore[symind] = ignorethis; 1120 val = sym + (skipsym(sym) - sym); 1121 if (definethis) { 1122 if (*val == '=') { 1123 value[symind] = val+1; 1124 *val = '\0'; 1125 } else if (*val == '\0') 1126 value[symind] = ""; 1127 else 1128 usage(); 1129 } else { 1130 if (*val != '\0') 1131 usage(); 1132 value[symind] = NULL; 1133 } 1134 } 1135 1136 /* 1137 * Compare s with n characters of t. 1138 * The same as strncmp() except that it checks that s[n] == '\0'. 1139 */ 1140 static int 1141 strlcmp(const char *s, const char *t, size_t n) 1142 { 1143 while (n-- && *t != '\0') 1144 if (*s != *t) 1145 return ((unsigned char)*s - (unsigned char)*t); 1146 else 1147 ++s, ++t; 1148 return ((unsigned char)*s); 1149 } 1150 1151 /* 1152 * Diagnostics. 1153 */ 1154 static void 1155 debug(const char *msg, ...) 1156 { 1157 va_list ap; 1158 1159 if (debugging) { 1160 va_start(ap, msg); 1161 vwarnx(msg, ap); 1162 va_end(ap); 1163 } 1164 } 1165 1166 static void 1167 error(const char *msg) 1168 { 1169 if (depth == 0) 1170 warnx("%s: %d: %s", filename, linenum, msg); 1171 else 1172 warnx("%s: %d: %s (#if line %d depth %d)", 1173 filename, linenum, msg, stifline[depth], depth); 1174 errx(2, "output may be truncated"); 1175 } 1176