1 /* 2 * Copyright (c) 2002 - 2005 Tony Finch <dot@dotat.at>. All rights reserved. 3 * 4 * This code is derived from software contributed to Berkeley by Dave Yost. 5 * It was rewritten to support ANSI C by Tony Finch. The original version of 6 * unifdef carried the following copyright notice. None of its code remains 7 * in this version (though some of the names remain). 8 * 9 * Copyright (c) 1985, 1993 10 * The Regents of the University of California. All rights reserved. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#) Copyright (c) 1985, 1993\n\ 34 * The Regents of the University of California. All rights reserved. 35 * @(#)unifdef.c 8.1 (Berkeley) 6/6/93 36 * 37 * $DragonFly: src/usr.bin/unifdef/unifdef.c,v 1.3 2005/07/25 17:51:36 hmp Exp $ 38 * $FreeBSD: src/usr.bin/unifdef/unifdef.c,v 1.20 2005/05/21 09:55:09 ru Exp $ 39 * $NetBSD: unifdef.c,v 1.8 2000/07/03 02:51:36 matt Exp $ 40 * $dotat: things/unifdef.c,v 1.171 2005/03/08 12:38:48 fanf2 Exp $" 41 */ 42 43 /* 44 * unifdef - remove ifdef'ed lines 45 * 46 * Wishlist: 47 * provide an option which will append the name of the 48 * appropriate symbol after #else's and #endif's 49 * provide an option which will check symbols after 50 * #else's and #endif's to see that they match their 51 * corresponding #ifdef or #ifndef 52 * 53 * The first two items above require better buffer handling, which would 54 * also make it possible to handle all "dodgy" directives correctly. 55 */ 56 57 #include <ctype.h> 58 #include <err.h> 59 #include <stdarg.h> 60 #include <stdbool.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <unistd.h> 65 66 /* types of input lines: */ 67 typedef enum { 68 LT_TRUEI, /* a true #if with ignore flag */ 69 LT_FALSEI, /* a false #if with ignore flag */ 70 LT_IF, /* an unknown #if */ 71 LT_TRUE, /* a true #if */ 72 LT_FALSE, /* a false #if */ 73 LT_ELIF, /* an unknown #elif */ 74 LT_ELTRUE, /* a true #elif */ 75 LT_ELFALSE, /* a false #elif */ 76 LT_ELSE, /* #else */ 77 LT_ENDIF, /* #endif */ 78 LT_DODGY, /* flag: directive is not on one line */ 79 LT_DODGY_LAST = LT_DODGY + LT_ENDIF, 80 LT_PLAIN, /* ordinary line */ 81 LT_EOF, /* end of file */ 82 LT_COUNT 83 } Linetype; 84 85 static char const * const linetype_name[] = { 86 "TRUEI", "FALSEI", "IF", "TRUE", "FALSE", 87 "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF", 88 "DODGY TRUEI", "DODGY FALSEI", 89 "DODGY IF", "DODGY TRUE", "DODGY FALSE", 90 "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE", 91 "DODGY ELSE", "DODGY ENDIF", 92 "PLAIN", "EOF" 93 }; 94 95 /* state of #if processing */ 96 typedef enum { 97 IS_OUTSIDE, 98 IS_FALSE_PREFIX, /* false #if followed by false #elifs */ 99 IS_TRUE_PREFIX, /* first non-false #(el)if is true */ 100 IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */ 101 IS_FALSE_MIDDLE, /* a false #elif after a pass state */ 102 IS_TRUE_MIDDLE, /* a true #elif after a pass state */ 103 IS_PASS_ELSE, /* an else after a pass state */ 104 IS_FALSE_ELSE, /* an else after a true state */ 105 IS_TRUE_ELSE, /* an else after only false states */ 106 IS_FALSE_TRAILER, /* #elifs after a true are false */ 107 IS_COUNT 108 } Ifstate; 109 110 static char const * const ifstate_name[] = { 111 "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX", 112 "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE", 113 "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE", 114 "FALSE_TRAILER" 115 }; 116 117 /* state of comment parser */ 118 typedef enum { 119 NO_COMMENT = false, /* outside a comment */ 120 C_COMMENT, /* in a comment like this one */ 121 CXX_COMMENT, /* between // and end of line */ 122 STARTING_COMMENT, /* just after slash-backslash-newline */ 123 FINISHING_COMMENT, /* star-backslash-newline in a C comment */ 124 CHAR_LITERAL, /* inside '' */ 125 STRING_LITERAL /* inside "" */ 126 } Comment_state; 127 128 static char const * const comment_name[] = { 129 "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING" 130 }; 131 132 /* state of preprocessor line parser */ 133 typedef enum { 134 LS_START, /* only space and comments on this line */ 135 LS_HASH, /* only space, comments, and a hash */ 136 LS_DIRTY /* this line can't be a preprocessor line */ 137 } Line_state; 138 139 static char const * const linestate_name[] = { 140 "START", "HASH", "DIRTY" 141 }; 142 143 /* 144 * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1 145 */ 146 #define MAXDEPTH 64 /* maximum #if nesting */ 147 #define MAXLINE 4096 /* maximum length of line */ 148 #define MAXSYMS 4096 /* maximum number of symbols */ 149 150 /* 151 * Sometimes when editing a keyword the replacement text is longer, so 152 * we leave some space at the end of the tline buffer to accommodate this. 153 */ 154 #define EDITSLOP 10 155 156 /* 157 * Globals. 158 */ 159 160 static bool complement; /* -c: do the complement */ 161 static bool debugging; /* -d: debugging reports */ 162 static bool iocccok; /* -e: fewer IOCCC errors */ 163 static bool killconsts; /* -k: eval constant #ifs */ 164 static bool lnblank; /* -l: blank deleted lines */ 165 static bool lnnum; /* -n: add #line directives */ 166 static bool symlist; /* -s: output symbol list */ 167 static bool text; /* -t: this is a text file */ 168 169 static const char *symname[MAXSYMS]; /* symbol name */ 170 static const char *value[MAXSYMS]; /* -Dsym=value */ 171 static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */ 172 static int nsyms; /* number of symbols */ 173 174 static FILE *input; /* input file pointer */ 175 static const char *filename; /* input file name */ 176 static int linenum; /* current line number */ 177 178 static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */ 179 static char *keyword; /* used for editing #elif's */ 180 181 static Comment_state incomment; /* comment parser state */ 182 static Line_state linestate; /* #if line parser state */ 183 static Ifstate ifstate[MAXDEPTH]; /* #if processor state */ 184 static bool ignoring[MAXDEPTH]; /* ignore comments state */ 185 static int stifline[MAXDEPTH]; /* start of current #if */ 186 static int depth; /* current #if nesting */ 187 static int delcount; /* count of deleted lines */ 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 done(void); 195 static void error(const char *); 196 static int findsym(const char *); 197 static void flushline(bool); 198 static Linetype getline(void); 199 static Linetype ifeval(const char **); 200 static void ignoreoff(void); 201 static void ignoreon(void); 202 static void keywordedit(const char *); 203 static void nest(void); 204 static void process(void); 205 static const char *skipcomment(const char *); 206 static const char *skipsym(const char *); 207 static void state(Ifstate); 208 static int strlcmp(const char *, const char *, size_t); 209 static void unnest(void); 210 static void usage(void); 211 212 #define endsym(c) (!isalpha((unsigned char)c) && !isdigit((unsigned char)c) && c != '_') 213 214 /* 215 * The main program. 216 */ 217 int 218 main(int argc, char *argv[]) 219 { 220 int opt; 221 222 while ((opt = getopt(argc, argv, "i:D:U:I:cdeklnst")) != -1) 223 switch (opt) { 224 case 'i': /* treat stuff controlled by these symbols as text */ 225 /* 226 * For strict backwards-compatibility the U or D 227 * should be immediately after the -i but it doesn't 228 * matter much if we relax that requirement. 229 */ 230 opt = *optarg++; 231 if (opt == 'D') 232 addsym(true, true, optarg); 233 else if (opt == 'U') 234 addsym(true, false, optarg); 235 else 236 usage(); 237 break; 238 case 'D': /* define a symbol */ 239 addsym(false, true, optarg); 240 break; 241 case 'U': /* undef a symbol */ 242 addsym(false, false, optarg); 243 break; 244 case 'I': 245 /* no-op for compatibility with cpp */ 246 break; 247 case 'c': /* treat -D as -U and vice versa */ 248 complement = true; 249 break; 250 case 'd': 251 debugging = true; 252 break; 253 case 'e': /* fewer errors from dodgy lines */ 254 iocccok = true; 255 break; 256 case 'k': /* process constant #ifs */ 257 killconsts = true; 258 break; 259 case 'l': /* blank deleted lines instead of omitting them */ 260 lnblank = true; 261 break; 262 case 'n': /* add #line directive after deleted lines */ 263 lnnum = true; 264 break; 265 case 's': /* only output list of symbols that control #ifs */ 266 symlist = true; 267 break; 268 case 't': /* don't parse C comments */ 269 text = true; 270 break; 271 default: 272 usage(); 273 } 274 argc -= optind; 275 argv += optind; 276 if (argc > 1) { 277 errx(2, "can only do one file"); 278 } else if (argc == 1 && strcmp(*argv, "-") != 0) { 279 filename = *argv; 280 input = fopen(filename, "r"); 281 if (input == NULL) 282 err(2, "can't open %s", filename); 283 } else { 284 filename = "[stdin]"; 285 input = stdin; 286 } 287 process(); 288 abort(); /* bug */ 289 } 290 291 static void 292 usage(void) 293 { 294 fprintf(stderr, "usage: unifdef [-cdeklnst] [-Ipath]" 295 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n"); 296 exit(2); 297 } 298 299 /* 300 * A state transition function alters the global #if processing state 301 * in a particular way. The table below is indexed by the current 302 * processing state and the type of the current line. 303 * 304 * Nesting is handled by keeping a stack of states; some transition 305 * functions increase or decrease the depth. They also maintain the 306 * ignore state on a stack. In some complicated cases they have to 307 * alter the preprocessor directive, as follows. 308 * 309 * When we have processed a group that starts off with a known-false 310 * #if/#elif sequence (which has therefore been deleted) followed by a 311 * #elif that we don't understand and therefore must keep, we edit the 312 * latter into a #if to keep the nesting correct. 313 * 314 * When we find a true #elif in a group, the following block will 315 * always be kept and the rest of the sequence after the next #elif or 316 * #else will be discarded. We edit the #elif into a #else and the 317 * following directive to #endif since this has the desired behaviour. 318 * 319 * "Dodgy" directives are split across multiple lines, the most common 320 * example being a multi-line comment hanging off the right of the 321 * directive. We can handle them correctly only if there is no change 322 * from printing to dropping (or vice versa) caused by that directive. 323 * If the directive is the first of a group we have a choice between 324 * failing with an error, or passing it through unchanged instead of 325 * evaluating it. The latter is not the default to avoid questions from 326 * users about unifdef unexpectedly leaving behind preprocessor directives. 327 */ 328 typedef void state_fn(void); 329 330 /* report an error */ 331 static void Eelif (void) { error("Inappropriate #elif"); } 332 static void Eelse (void) { error("Inappropriate #else"); } 333 static void Eendif(void) { error("Inappropriate #endif"); } 334 static void Eeof (void) { error("Premature EOF"); } 335 static void Eioccc(void) { error("Obfuscated preprocessor control line"); } 336 /* plain line handling */ 337 static void print (void) { flushline(true); } 338 static void drop (void) { flushline(false); } 339 /* output lacks group's start line */ 340 static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); } 341 static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); } 342 static void Selse (void) { drop(); state(IS_TRUE_ELSE); } 343 /* print/pass this block */ 344 static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); } 345 static void Pelse (void) { print(); state(IS_PASS_ELSE); } 346 static void Pendif(void) { print(); unnest(); } 347 /* discard this block */ 348 static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); } 349 static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); } 350 static void Delse (void) { drop(); state(IS_FALSE_ELSE); } 351 static void Dendif(void) { drop(); unnest(); } 352 /* first line of group */ 353 static void Fdrop (void) { nest(); Dfalse(); } 354 static void Fpass (void) { nest(); Pelif(); } 355 static void Ftrue (void) { nest(); Strue(); } 356 static void Ffalse(void) { nest(); Sfalse(); } 357 /* variable pedantry for obfuscated lines */ 358 static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); } 359 static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); } 360 static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); } 361 /* ignore comments in this block */ 362 static void Idrop (void) { Fdrop(); ignoreon(); } 363 static void Itrue (void) { Ftrue(); ignoreon(); } 364 static void Ifalse(void) { Ffalse(); ignoreon(); } 365 /* edit this line */ 366 static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); } 367 static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); } 368 static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); } 369 static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); } 370 371 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = { 372 /* IS_OUTSIDE */ 373 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif, 374 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif, 375 print, done }, 376 /* IS_FALSE_PREFIX */ 377 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif, 378 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc, 379 drop, Eeof }, 380 /* IS_TRUE_PREFIX */ 381 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif, 382 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 383 print, Eeof }, 384 /* IS_PASS_MIDDLE */ 385 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif, 386 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif, 387 print, Eeof }, 388 /* IS_FALSE_MIDDLE */ 389 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif, 390 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 391 drop, Eeof }, 392 /* IS_TRUE_MIDDLE */ 393 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif, 394 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif, 395 print, Eeof }, 396 /* IS_PASS_ELSE */ 397 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif, 398 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif, 399 print, Eeof }, 400 /* IS_FALSE_ELSE */ 401 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif, 402 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc, 403 drop, Eeof }, 404 /* IS_TRUE_ELSE */ 405 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif, 406 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc, 407 print, Eeof }, 408 /* IS_FALSE_TRAILER */ 409 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif, 410 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc, 411 drop, Eeof } 412 /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF 413 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY) 414 PLAIN EOF */ 415 }; 416 417 /* 418 * State machine utility functions 419 */ 420 static void 421 done(void) 422 { 423 if (incomment) 424 error("EOF in comment"); 425 exit(exitstat); 426 } 427 static void 428 ignoreoff(void) 429 { 430 if (depth == 0) 431 abort(); /* bug */ 432 ignoring[depth] = ignoring[depth-1]; 433 } 434 static void 435 ignoreon(void) 436 { 437 ignoring[depth] = true; 438 } 439 static void 440 keywordedit(const char *replacement) 441 { 442 strlcpy(keyword, replacement, tline + sizeof(tline) - keyword); 443 print(); 444 } 445 static void 446 nest(void) 447 { 448 depth += 1; 449 if (depth >= MAXDEPTH) 450 error("Too many levels of nesting"); 451 stifline[depth] = linenum; 452 } 453 static void 454 unnest(void) 455 { 456 if (depth == 0) 457 abort(); /* bug */ 458 depth -= 1; 459 } 460 static void 461 state(Ifstate is) 462 { 463 ifstate[depth] = is; 464 } 465 466 /* 467 * Write a line to the output or not, according to command line options. 468 */ 469 static void 470 flushline(bool keep) 471 { 472 if (symlist) 473 return; 474 if (keep ^ complement) { 475 if (lnnum && delcount > 0) 476 printf("#line %d\n", linenum); 477 fputs(tline, stdout); 478 delcount = 0; 479 } else { 480 if (lnblank) 481 putc('\n', stdout); 482 exitstat = 1; 483 delcount += 1; 484 } 485 } 486 487 /* 488 * The driver for the state machine. 489 */ 490 static void 491 process(void) 492 { 493 Linetype lineval; 494 495 for (;;) { 496 linenum++; 497 lineval = getline(); 498 trans_table[ifstate[depth]][lineval](); 499 debug("process %s -> %s depth %d", 500 linetype_name[lineval], 501 ifstate_name[ifstate[depth]], depth); 502 } 503 } 504 505 /* 506 * Parse a line and determine its type. We keep the preprocessor line 507 * parser state between calls in the global variable linestate, with 508 * help from skipcomment(). 509 */ 510 static Linetype 511 getline(void) 512 { 513 const char *cp; 514 int cursym; 515 int kwlen; 516 Linetype retval; 517 Comment_state wascomment; 518 519 if (fgets(tline, MAXLINE, input) == NULL) 520 return (LT_EOF); 521 retval = LT_PLAIN; 522 wascomment = incomment; 523 cp = skipcomment(tline); 524 if (linestate == LS_START) { 525 if (*cp == '#') { 526 linestate = LS_HASH; 527 cp = skipcomment(cp + 1); 528 } else if (*cp != '\0') 529 linestate = LS_DIRTY; 530 } 531 if (!incomment && linestate == LS_HASH) { 532 keyword = tline + (cp - tline); 533 cp = skipsym(cp); 534 kwlen = cp - keyword; 535 /* no way can we deal with a continuation inside a keyword */ 536 if (strncmp(cp, "\\\n", 2) == 0) 537 Eioccc(); 538 if (strlcmp("ifdef", keyword, kwlen) == 0 || 539 strlcmp("ifndef", keyword, kwlen) == 0) { 540 cp = skipcomment(cp); 541 if ((cursym = findsym(cp)) < 0) 542 retval = LT_IF; 543 else { 544 retval = (keyword[2] == 'n') 545 ? LT_FALSE : LT_TRUE; 546 if (value[cursym] == NULL) 547 retval = (retval == LT_TRUE) 548 ? LT_FALSE : LT_TRUE; 549 if (ignore[cursym]) 550 retval = (retval == LT_TRUE) 551 ? LT_TRUEI : LT_FALSEI; 552 } 553 cp = skipsym(cp); 554 } else if (strlcmp("if", keyword, kwlen) == 0) 555 retval = ifeval(&cp); 556 else if (strlcmp("elif", keyword, kwlen) == 0) 557 retval = ifeval(&cp) - LT_IF + LT_ELIF; 558 else if (strlcmp("else", keyword, kwlen) == 0) 559 retval = LT_ELSE; 560 else if (strlcmp("endif", keyword, kwlen) == 0) 561 retval = LT_ENDIF; 562 else { 563 linestate = LS_DIRTY; 564 retval = LT_PLAIN; 565 } 566 cp = skipcomment(cp); 567 if (*cp != '\0') { 568 linestate = LS_DIRTY; 569 if (retval == LT_TRUE || retval == LT_FALSE || 570 retval == LT_TRUEI || retval == LT_FALSEI) 571 retval = LT_IF; 572 if (retval == LT_ELTRUE || retval == LT_ELFALSE) 573 retval = LT_ELIF; 574 } 575 if (retval != LT_PLAIN && (wascomment || incomment)) { 576 retval += LT_DODGY; 577 if (incomment) 578 linestate = LS_DIRTY; 579 } 580 /* skipcomment should have changed the state */ 581 if (linestate == LS_HASH) 582 abort(); /* bug */ 583 } 584 if (linestate == LS_DIRTY) { 585 while (*cp != '\0') 586 cp = skipcomment(cp + 1); 587 } 588 debug("parser %s comment %s line", 589 comment_name[incomment], linestate_name[linestate]); 590 return (retval); 591 } 592 593 /* 594 * These are the binary operators that are supported by the expression 595 * evaluator. Note that if support for division is added then we also 596 * need short-circuiting booleans because of divide-by-zero. 597 */ 598 static int op_lt(int a, int b) { return (a < b); } 599 static int op_gt(int a, int b) { return (a > b); } 600 static int op_le(int a, int b) { return (a <= b); } 601 static int op_ge(int a, int b) { return (a >= b); } 602 static int op_eq(int a, int b) { return (a == b); } 603 static int op_ne(int a, int b) { return (a != b); } 604 static int op_or(int a, int b) { return (a || b); } 605 static int op_and(int a, int b) { return (a && b); } 606 607 /* 608 * An evaluation function takes three arguments, as follows: (1) a pointer to 609 * an element of the precedence table which lists the operators at the current 610 * level of precedence; (2) a pointer to an integer which will receive the 611 * value of the expression; and (3) a pointer to a char* that points to the 612 * expression to be evaluated and that is updated to the end of the expression 613 * when evaluation is complete. The function returns LT_FALSE if the value of 614 * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the 615 * expression could not be evaluated. 616 */ 617 struct ops; 618 619 typedef Linetype eval_fn(const struct ops *, int *, const char **); 620 621 static eval_fn eval_table, eval_unary; 622 623 /* 624 * The precedence table. Expressions involving binary operators are evaluated 625 * in a table-driven way by eval_table. When it evaluates a subexpression it 626 * calls the inner function with its first argument pointing to the next 627 * element of the table. Innermost expressions have special non-table-driven 628 * handling. 629 */ 630 static const struct ops { 631 eval_fn *inner; 632 struct op { 633 const char *str; 634 int (*fn)(int, int); 635 } op[5]; 636 } eval_ops[] = { 637 { eval_table, { { "||", op_or } } }, 638 { eval_table, { { "&&", op_and } } }, 639 { eval_table, { { "==", op_eq }, 640 { "!=", op_ne } } }, 641 { eval_unary, { { "<=", op_le }, 642 { ">=", op_ge }, 643 { "<", op_lt }, 644 { ">", op_gt } } } 645 }; 646 647 /* 648 * Function for evaluating the innermost parts of expressions, 649 * viz. !expr (expr) defined(symbol) symbol number 650 * We reset the keepthis flag when we find a non-constant subexpression. 651 */ 652 static Linetype 653 eval_unary(const struct ops *ops, int *valp, const char **cpp) 654 { 655 const char *cp; 656 char *ep; 657 int sym; 658 659 cp = skipcomment(*cpp); 660 if (*cp == '!') { 661 debug("eval%d !", ops - eval_ops); 662 cp++; 663 if (eval_unary(ops, valp, &cp) == LT_IF) 664 return (LT_IF); 665 *valp = !*valp; 666 } else if (*cp == '(') { 667 cp++; 668 debug("eval%d (", ops - eval_ops); 669 if (eval_table(eval_ops, valp, &cp) == LT_IF) 670 return (LT_IF); 671 cp = skipcomment(cp); 672 if (*cp++ != ')') 673 return (LT_IF); 674 } else if (isdigit((unsigned char)*cp)) { 675 debug("eval%d number", ops - eval_ops); 676 *valp = strtol(cp, &ep, 0); 677 cp = skipsym(cp); 678 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) { 679 cp = skipcomment(cp+7); 680 debug("eval%d defined", ops - eval_ops); 681 if (*cp++ != '(') 682 return (LT_IF); 683 cp = skipcomment(cp); 684 sym = findsym(cp); 685 if (sym < 0) 686 return (LT_IF); 687 *valp = (value[sym] != NULL); 688 cp = skipsym(cp); 689 cp = skipcomment(cp); 690 if (*cp++ != ')') 691 return (LT_IF); 692 keepthis = false; 693 } else if (!endsym(*cp)) { 694 debug("eval%d symbol", ops - eval_ops); 695 sym = findsym(cp); 696 if (sym < 0) 697 return (LT_IF); 698 if (value[sym] == NULL) 699 *valp = 0; 700 else { 701 *valp = strtol(value[sym], &ep, 0); 702 if (*ep != '\0' || ep == value[sym]) 703 return (LT_IF); 704 } 705 cp = skipsym(cp); 706 keepthis = false; 707 } else { 708 debug("eval%d bad expr", ops - eval_ops); 709 return (LT_IF); 710 } 711 712 *cpp = cp; 713 debug("eval%d = %d", ops - eval_ops, *valp); 714 return (*valp ? LT_TRUE : LT_FALSE); 715 } 716 717 /* 718 * Table-driven evaluation of binary operators. 719 */ 720 static Linetype 721 eval_table(const struct ops *ops, int *valp, const char **cpp) 722 { 723 const struct op *op; 724 const char *cp; 725 int val; 726 727 debug("eval%d", ops - eval_ops); 728 cp = *cpp; 729 if (ops->inner(ops+1, valp, &cp) == LT_IF) 730 return (LT_IF); 731 for (;;) { 732 cp = skipcomment(cp); 733 for (op = ops->op; op->str != NULL; op++) 734 if (strncmp(cp, op->str, strlen(op->str)) == 0) 735 break; 736 if (op->str == NULL) 737 break; 738 cp += strlen(op->str); 739 debug("eval%d %s", ops - eval_ops, op->str); 740 if (ops->inner(ops+1, &val, &cp) == LT_IF) 741 return (LT_IF); 742 *valp = op->fn(*valp, val); 743 } 744 745 *cpp = cp; 746 debug("eval%d = %d", ops - eval_ops, *valp); 747 return (*valp ? LT_TRUE : LT_FALSE); 748 } 749 750 /* 751 * Evaluate the expression on a #if or #elif line. If we can work out 752 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we 753 * return just a generic LT_IF. 754 */ 755 static Linetype 756 ifeval(const char **cpp) 757 { 758 int ret; 759 int val; 760 761 debug("eval %s", *cpp); 762 keepthis = killconsts ? false : true; 763 ret = eval_table(eval_ops, &val, cpp); 764 debug("eval = %d", val); 765 return (keepthis ? LT_IF : ret); 766 } 767 768 /* 769 * Skip over comments, strings, and character literals and stop at the 770 * next character position that is not whitespace. Between calls we keep 771 * the comment state in the global variable incomment, and we also adjust 772 * the global variable linestate when we see a newline. 773 * XXX: doesn't cope with the buffer splitting inside a state transition. 774 */ 775 static const char * 776 skipcomment(const char *cp) 777 { 778 if (text || ignoring[depth]) { 779 for (; isspace((unsigned char)*cp); cp++) 780 if (*cp == '\n') 781 linestate = LS_START; 782 return (cp); 783 } 784 while (*cp != '\0') 785 /* don't reset to LS_START after a line continuation */ 786 if (strncmp(cp, "\\\n", 2) == 0) 787 cp += 2; 788 else switch (incomment) { 789 case NO_COMMENT: 790 if (strncmp(cp, "/\\\n", 3) == 0) { 791 incomment = STARTING_COMMENT; 792 cp += 3; 793 } else if (strncmp(cp, "/*", 2) == 0) { 794 incomment = C_COMMENT; 795 cp += 2; 796 } else if (strncmp(cp, "//", 2) == 0) { 797 incomment = CXX_COMMENT; 798 cp += 2; 799 } else if (strncmp(cp, "\'", 1) == 0) { 800 incomment = CHAR_LITERAL; 801 linestate = LS_DIRTY; 802 cp += 1; 803 } else if (strncmp(cp, "\"", 1) == 0) { 804 incomment = STRING_LITERAL; 805 linestate = LS_DIRTY; 806 cp += 1; 807 } else if (strncmp(cp, "\n", 1) == 0) { 808 linestate = LS_START; 809 cp += 1; 810 } else if (strchr(" \t", *cp) != NULL) { 811 cp += 1; 812 } else 813 return (cp); 814 continue; 815 case CXX_COMMENT: 816 if (strncmp(cp, "\n", 1) == 0) { 817 incomment = NO_COMMENT; 818 linestate = LS_START; 819 } 820 cp += 1; 821 continue; 822 case CHAR_LITERAL: 823 case STRING_LITERAL: 824 if ((incomment == CHAR_LITERAL && cp[0] == '\'') || 825 (incomment == STRING_LITERAL && cp[0] == '\"')) { 826 incomment = NO_COMMENT; 827 cp += 1; 828 } else if (cp[0] == '\\') { 829 if (cp[1] == '\0') 830 cp += 1; 831 else 832 cp += 2; 833 } else if (strncmp(cp, "\n", 1) == 0) { 834 if (incomment == CHAR_LITERAL) 835 error("unterminated char literal"); 836 else 837 error("unterminated string literal"); 838 } else 839 cp += 1; 840 continue; 841 case C_COMMENT: 842 if (strncmp(cp, "*\\\n", 3) == 0) { 843 incomment = FINISHING_COMMENT; 844 cp += 3; 845 } else if (strncmp(cp, "*/", 2) == 0) { 846 incomment = NO_COMMENT; 847 cp += 2; 848 } else 849 cp += 1; 850 continue; 851 case STARTING_COMMENT: 852 if (*cp == '*') { 853 incomment = C_COMMENT; 854 cp += 1; 855 } else if (*cp == '/') { 856 incomment = CXX_COMMENT; 857 cp += 1; 858 } else { 859 incomment = NO_COMMENT; 860 linestate = LS_DIRTY; 861 } 862 continue; 863 case FINISHING_COMMENT: 864 if (*cp == '/') { 865 incomment = NO_COMMENT; 866 cp += 1; 867 } else 868 incomment = C_COMMENT; 869 continue; 870 default: 871 abort(); /* bug */ 872 } 873 return (cp); 874 } 875 876 /* 877 * Skip over an identifier. 878 */ 879 static const char * 880 skipsym(const char *cp) 881 { 882 while (!endsym(*cp)) 883 ++cp; 884 return (cp); 885 } 886 887 /* 888 * Look for the symbol in the symbol table. If is is found, we return 889 * the symbol table index, else we return -1. 890 */ 891 static int 892 findsym(const char *str) 893 { 894 const char *cp; 895 int symind; 896 897 cp = skipsym(str); 898 if (cp == str) 899 return (-1); 900 if (symlist) { 901 printf("%.*s\n", (int)(cp-str), str); 902 /* we don't care about the value of the symbol */ 903 return (0); 904 } 905 for (symind = 0; symind < nsyms; ++symind) { 906 if (strlcmp(symname[symind], str, cp-str) == 0) { 907 debug("findsym %s %s", symname[symind], 908 value[symind] ? value[symind] : ""); 909 return (symind); 910 } 911 } 912 return (-1); 913 } 914 915 /* 916 * Add a symbol to the symbol table. 917 */ 918 static void 919 addsym(bool ignorethis, bool definethis, char *sym) 920 { 921 int symind; 922 char *val; 923 924 symind = findsym(sym); 925 if (symind < 0) { 926 if (nsyms >= MAXSYMS) 927 errx(2, "too many symbols"); 928 symind = nsyms++; 929 } 930 symname[symind] = sym; 931 ignore[symind] = ignorethis; 932 val = sym + (skipsym(sym) - sym); 933 if (definethis) { 934 if (*val == '=') { 935 value[symind] = val+1; 936 *val = '\0'; 937 } else if (*val == '\0') 938 value[symind] = ""; 939 else 940 usage(); 941 } else { 942 if (*val != '\0') 943 usage(); 944 value[symind] = NULL; 945 } 946 } 947 948 /* 949 * Compare s with n characters of t. 950 * The same as strncmp() except that it checks that s[n] == '\0'. 951 */ 952 static int 953 strlcmp(const char *s, const char *t, size_t n) 954 { 955 while (n-- && *t != '\0') 956 if (*s != *t) 957 return ((unsigned char)*s - (unsigned char)*t); 958 else 959 ++s, ++t; 960 return ((unsigned char)*s); 961 } 962 963 /* 964 * Diagnostics. 965 */ 966 static void 967 debug(const char *msg, ...) 968 { 969 va_list ap; 970 971 if (debugging) { 972 va_start(ap, msg); 973 vwarnx(msg, ap); 974 va_end(ap); 975 } 976 } 977 978 static void 979 error(const char *msg) 980 { 981 if (depth == 0) 982 warnx("%s: %d: %s", filename, linenum, msg); 983 else 984 warnx("%s: %d: %s (#if line %d depth %d)", 985 filename, linenum, msg, stifline[depth], depth); 986 errx(2, "output may be truncated"); 987 } 988