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 34 #include <sys/cdefs.h> 35 36 #ifndef lint 37 #if 0 38 static const char copyright[] = 39 "@(#) Copyright (c) 1985, 1993\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif 42 #ifdef __IDSTRING 43 __IDSTRING(Berkeley, "@(#)unifdef.c 8.1 (Berkeley) 6/6/93"); 44 __IDSTRING(NetBSD, "$NetBSD: unifdef.c,v 1.8 2000/07/03 02:51:36 matt Exp $"); 45 __IDSTRING(dotat, "$dotat: things/unifdef.c,v 1.171 2005/03/08 12:38:48 fanf2 Exp $"); 46 #endif 47 #endif /* not lint */ 48 #ifdef __FBSDID 49 __FBSDID("$FreeBSD: /repoman/r/ncvs/src/usr.bin/unifdef/unifdef.c,v 1.20 2005/05/21 09:55:09 ru Exp $"); 50 #endif 51 52 /* 53 * unifdef - remove ifdef'ed lines 54 * 55 * Wishlist: 56 * provide an option which will append the name of the 57 * appropriate symbol after #else's and #endif's 58 * provide an option which will check symbols after 59 * #else's and #endif's to see that they match their 60 * corresponding #ifdef or #ifndef 61 * 62 * The first two items above require better buffer handling, which would 63 * also make it possible to handle all "dodgy" directives correctly. 64 */ 65 66 #include <ctype.h> 67 #include <err.h> 68 #include <stdarg.h> 69 #include <stdbool.h> 70 #include <stdio.h> 71 #include <stdlib.h> 72 #include <string.h> 73 #include <unistd.h> 74 75 size_t strlcpy(char *dst, const char *src, size_t siz); 76 77 /* types of input lines: */ 78 typedef enum { 79 LT_TRUEI, /* a true #if with ignore flag */ 80 LT_FALSEI, /* a false #if with ignore flag */ 81 LT_IF, /* an unknown #if */ 82 LT_TRUE, /* a true #if */ 83 LT_FALSE, /* a false #if */ 84 LT_ELIF, /* an unknown #elif */ 85 LT_ELTRUE, /* a true #elif */ 86 LT_ELFALSE, /* a false #elif */ 87 LT_ELSE, /* #else */ 88 LT_ENDIF, /* #endif */ 89 LT_DODGY, /* flag: directive is not on one line */ 90 LT_DODGY_LAST = LT_DODGY + LT_ENDIF, 91 LT_PLAIN, /* ordinary line */ 92 LT_EOF, /* end of file */ 93 LT_COUNT 94 } Linetype; 95 96 static char const * const linetype_name[] = { 97 "TRUEI", "FALSEI", "IF", "TRUE", "FALSE", 98 "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF", 99 "DODGY TRUEI", "DODGY FALSEI", 100 "DODGY IF", "DODGY TRUE", "DODGY FALSE", 101 "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE", 102 "DODGY ELSE", "DODGY ENDIF", 103 "PLAIN", "EOF" 104 }; 105 106 /* state of #if processing */ 107 typedef enum { 108 IS_OUTSIDE, 109 IS_FALSE_PREFIX, /* false #if followed by false #elifs */ 110 IS_TRUE_PREFIX, /* first non-false #(el)if is true */ 111 IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */ 112 IS_FALSE_MIDDLE, /* a false #elif after a pass state */ 113 IS_TRUE_MIDDLE, /* a true #elif after a pass state */ 114 IS_PASS_ELSE, /* an else after a pass state */ 115 IS_FALSE_ELSE, /* an else after a true state */ 116 IS_TRUE_ELSE, /* an else after only false states */ 117 IS_FALSE_TRAILER, /* #elifs after a true are false */ 118 IS_COUNT 119 } Ifstate; 120 121 static char const * const ifstate_name[] = { 122 "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX", 123 "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE", 124 "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE", 125 "FALSE_TRAILER" 126 }; 127 128 /* state of comment parser */ 129 typedef enum { 130 NO_COMMENT = false, /* outside a comment */ 131 C_COMMENT, /* in a comment like this one */ 132 CXX_COMMENT, /* between // and end of line */ 133 STARTING_COMMENT, /* just after slash-backslash-newline */ 134 FINISHING_COMMENT, /* star-backslash-newline in a C comment */ 135 CHAR_LITERAL, /* inside '' */ 136 STRING_LITERAL /* inside "" */ 137 } Comment_state; 138 139 static char const * const comment_name[] = { 140 "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING" 141 }; 142 143 /* state of preprocessor line parser */ 144 typedef enum { 145 LS_START, /* only space and comments on this line */ 146 LS_HASH, /* only space, comments, and a hash */ 147 LS_DIRTY /* this line can't be a preprocessor line */ 148 } Line_state; 149 150 static char const * const linestate_name[] = { 151 "START", "HASH", "DIRTY" 152 }; 153 154 /* 155 * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1 156 */ 157 #define MAXDEPTH 64 /* maximum #if nesting */ 158 #define MAXLINE 4096 /* maximum length of line */ 159 #define MAXSYMS 4096 /* maximum number of symbols */ 160 161 /* 162 * Sometimes when editing a keyword the replacement text is longer, so 163 * we leave some space at the end of the tline buffer to accommodate this. 164 */ 165 #define EDITSLOP 10 166 167 /* 168 * Globals. 169 */ 170 171 static bool complement; /* -c: do the complement */ 172 static bool debugging; /* -d: debugging reports */ 173 static bool iocccok; /* -e: fewer IOCCC errors */ 174 static bool killconsts; /* -k: eval constant #ifs */ 175 static bool lnblank; /* -l: blank deleted lines */ 176 static bool lnnum; /* -n: add #line directives */ 177 static bool symlist; /* -s: output symbol list */ 178 static bool text; /* -t: this is a text file */ 179 180 static const char *symname[MAXSYMS]; /* symbol name */ 181 static const char *value[MAXSYMS]; /* -Dsym=value */ 182 static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */ 183 static int nsyms; /* number of symbols */ 184 185 static FILE *input; /* input file pointer */ 186 static const char *filename; /* input file name */ 187 static int linenum; /* current line number */ 188 189 static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */ 190 static char *keyword; /* used for editing #elif's */ 191 192 static Comment_state incomment; /* comment parser state */ 193 static Line_state linestate; /* #if line parser state */ 194 static Ifstate ifstate[MAXDEPTH]; /* #if processor state */ 195 static bool ignoring[MAXDEPTH]; /* ignore comments state */ 196 static int stifline[MAXDEPTH]; /* start of current #if */ 197 static int depth; /* current #if nesting */ 198 static int delcount; /* count of deleted lines */ 199 static bool keepthis; /* don't delete constant #if */ 200 201 static int exitstat; /* program exit status */ 202 203 static void addsym(bool, bool, char *); 204 static void debug(const char *, ...); 205 static void done(void); 206 static void error(const char *); 207 static int findsym(const char *); 208 static void flushline(bool); 209 static Linetype getline(void); 210 static Linetype ifeval(const char **); 211 static void ignoreoff(void); 212 static void ignoreon(void); 213 static void keywordedit(const char *); 214 static void nest(void); 215 static void process(void); 216 static const char *skipcomment(const char *); 217 static const char *skipsym(const char *); 218 static void state(Ifstate); 219 static int strlcmp(const char *, const char *, size_t); 220 static void unnest(void); 221 static void usage(void); 222 223 #define endsym(c) (!isalpha((unsigned char)c) && !isdigit((unsigned char)c) && c != '_') 224 225 /* 226 * The main program. 227 */ 228 int 229 main(int argc, char *argv[]) 230 { 231 int opt; 232 233 while ((opt = getopt(argc, argv, "i:D:U:I:cdeklnst")) != -1) 234 switch (opt) { 235 case 'i': /* treat stuff controlled by these symbols as text */ 236 /* 237 * For strict backwards-compatibility the U or D 238 * should be immediately after the -i but it doesn't 239 * matter much if we relax that requirement. 240 */ 241 opt = *optarg++; 242 if (opt == 'D') 243 addsym(true, true, optarg); 244 else if (opt == 'U') 245 addsym(true, false, optarg); 246 else 247 usage(); 248 break; 249 case 'D': /* define a symbol */ 250 addsym(false, true, optarg); 251 break; 252 case 'U': /* undef a symbol */ 253 addsym(false, false, optarg); 254 break; 255 case 'I': 256 /* no-op for compatibility with cpp */ 257 break; 258 case 'c': /* treat -D as -U and vice versa */ 259 complement = true; 260 break; 261 case 'd': 262 debugging = true; 263 break; 264 case 'e': /* fewer errors from dodgy lines */ 265 iocccok = true; 266 break; 267 case 'k': /* process constant #ifs */ 268 killconsts = true; 269 break; 270 case 'l': /* blank deleted lines instead of omitting them */ 271 lnblank = true; 272 break; 273 case 'n': /* add #line directive after deleted lines */ 274 lnnum = true; 275 break; 276 case 's': /* only output list of symbols that control #ifs */ 277 symlist = true; 278 break; 279 case 't': /* don't parse C comments */ 280 text = true; 281 break; 282 default: 283 usage(); 284 } 285 argc -= optind; 286 argv += optind; 287 if (argc > 1) { 288 errx(2, "can only do one file"); 289 } else if (argc == 1 && strcmp(*argv, "-") != 0) { 290 filename = *argv; 291 input = fopen(filename, "r"); 292 if (input == NULL) 293 err(2, "can't open %s", filename); 294 } else { 295 filename = "[stdin]"; 296 input = stdin; 297 } 298 process(); 299 abort(); /* bug */ 300 } 301 302 static void 303 usage(void) 304 { 305 fprintf(stderr, "usage: unifdef [-cdeklnst] [-Ipath]" 306 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n"); 307 exit(2); 308 } 309 310 /* 311 * A state transition function alters the global #if processing state 312 * in a particular way. The table below is indexed by the current 313 * processing state and the type of the current line. 314 * 315 * Nesting is handled by keeping a stack of states; some transition 316 * functions increase or decrease the depth. They also maintain the 317 * ignore state on a stack. In some complicated cases they have to 318 * alter the preprocessor directive, as follows. 319 * 320 * When we have processed a group that starts off with a known-false 321 * #if/#elif sequence (which has therefore been deleted) followed by a 322 * #elif that we don't understand and therefore must keep, we edit the 323 * latter into a #if to keep the nesting correct. 324 * 325 * When we find a true #elif in a group, the following block will 326 * always be kept and the rest of the sequence after the next #elif or 327 * #else will be discarded. We edit the #elif into a #else and the 328 * following directive to #endif since this has the desired behaviour. 329 * 330 * "Dodgy" directives are split across multiple lines, the most common 331 * example being a multi-line comment hanging off the right of the 332 * directive. We can handle them correctly only if there is no change 333 * from printing to dropping (or vice versa) caused by that directive. 334 * If the directive is the first of a group we have a choice between 335 * failing with an error, or passing it through unchanged instead of 336 * evaluating it. The latter is not the default to avoid questions from 337 * users about unifdef unexpectedly leaving behind preprocessor directives. 338 */ 339 typedef void state_fn(void); 340 341 /* report an error */ 342 static void Eelif (void) { error("Inappropriate #elif"); } 343 static void Eelse (void) { error("Inappropriate #else"); } 344 static void Eendif(void) { error("Inappropriate #endif"); } 345 static void Eeof (void) { error("Premature EOF"); } 346 static void Eioccc(void) { error("Obfuscated preprocessor control line"); } 347 /* plain line handling */ 348 static void print (void) { flushline(true); } 349 static void drop (void) { flushline(false); } 350 /* output lacks group's start line */ 351 static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); } 352 static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); } 353 static void Selse (void) { drop(); state(IS_TRUE_ELSE); } 354 /* print/pass this block */ 355 static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); } 356 static void Pelse (void) { print(); state(IS_PASS_ELSE); } 357 static void Pendif(void) { print(); unnest(); } 358 /* discard this block */ 359 static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); } 360 static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); } 361 static void Delse (void) { drop(); state(IS_FALSE_ELSE); } 362 static void Dendif(void) { drop(); unnest(); } 363 /* first line of group */ 364 static void Fdrop (void) { nest(); Dfalse(); } 365 static void Fpass (void) { nest(); Pelif(); } 366 static void Ftrue (void) { nest(); Strue(); } 367 static void Ffalse(void) { nest(); Sfalse(); } 368 /* variable pedantry for obfuscated lines */ 369 static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); } 370 static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); } 371 static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); } 372 /* ignore comments in this block */ 373 static void Idrop (void) { Fdrop(); ignoreon(); } 374 static void Itrue (void) { Ftrue(); ignoreon(); } 375 static void Ifalse(void) { Ffalse(); ignoreon(); } 376 /* edit this line */ 377 static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); } 378 static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); } 379 static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); } 380 static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); } 381 382 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = { 383 /* IS_OUTSIDE */ 384 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif, 385 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif, 386 print, done }, 387 /* IS_FALSE_PREFIX */ 388 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif, 389 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc, 390 drop, Eeof }, 391 /* IS_TRUE_PREFIX */ 392 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif, 393 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 394 print, Eeof }, 395 /* IS_PASS_MIDDLE */ 396 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif, 397 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif, 398 print, Eeof }, 399 /* IS_FALSE_MIDDLE */ 400 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif, 401 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 402 drop, Eeof }, 403 /* IS_TRUE_MIDDLE */ 404 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif, 405 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif, 406 print, Eeof }, 407 /* IS_PASS_ELSE */ 408 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif, 409 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif, 410 print, Eeof }, 411 /* IS_FALSE_ELSE */ 412 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif, 413 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc, 414 drop, Eeof }, 415 /* IS_TRUE_ELSE */ 416 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif, 417 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc, 418 print, Eeof }, 419 /* IS_FALSE_TRAILER */ 420 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif, 421 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc, 422 drop, Eeof } 423 /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF 424 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY) 425 PLAIN EOF */ 426 }; 427 428 /* 429 * State machine utility functions 430 */ 431 static void 432 done(void) 433 { 434 if (incomment) 435 error("EOF in comment"); 436 exit(exitstat); 437 } 438 static void 439 ignoreoff(void) 440 { 441 if (depth == 0) 442 abort(); /* bug */ 443 ignoring[depth] = ignoring[depth-1]; 444 } 445 static void 446 ignoreon(void) 447 { 448 ignoring[depth] = true; 449 } 450 static void 451 keywordedit(const char *replacement) 452 { 453 size_t size = tline + sizeof(tline) - keyword; 454 char *dst = keyword; 455 const char *src = replacement; 456 if (size != 0) { 457 while ((--size != 0) && (*src != '\0')) 458 *dst++ = *src++; 459 *dst = '\0'; 460 } 461 print(); 462 } 463 static void 464 nest(void) 465 { 466 depth += 1; 467 if (depth >= MAXDEPTH) 468 error("Too many levels of nesting"); 469 stifline[depth] = linenum; 470 } 471 static void 472 unnest(void) 473 { 474 if (depth == 0) 475 abort(); /* bug */ 476 depth -= 1; 477 } 478 static void 479 state(Ifstate is) 480 { 481 ifstate[depth] = is; 482 } 483 484 /* 485 * Write a line to the output or not, according to command line options. 486 */ 487 static void 488 flushline(bool keep) 489 { 490 if (symlist) 491 return; 492 if (keep ^ complement) { 493 if (lnnum && delcount > 0) 494 printf("#line %d\n", linenum); 495 fputs(tline, stdout); 496 delcount = 0; 497 } else { 498 if (lnblank) 499 putc('\n', stdout); 500 exitstat = 1; 501 delcount += 1; 502 } 503 } 504 505 /* 506 * The driver for the state machine. 507 */ 508 static void 509 process(void) 510 { 511 Linetype lineval; 512 513 for (;;) { 514 linenum++; 515 lineval = getline(); 516 trans_table[ifstate[depth]][lineval](); 517 debug("process %s -> %s depth %d", 518 linetype_name[lineval], 519 ifstate_name[ifstate[depth]], depth); 520 } 521 } 522 523 /* 524 * Parse a line and determine its type. We keep the preprocessor line 525 * parser state between calls in the global variable linestate, with 526 * help from skipcomment(). 527 */ 528 static Linetype 529 getline(void) 530 { 531 const char *cp; 532 int cursym; 533 int kwlen; 534 Linetype retval; 535 Comment_state wascomment; 536 537 if (fgets(tline, MAXLINE, input) == NULL) 538 return (LT_EOF); 539 retval = LT_PLAIN; 540 wascomment = incomment; 541 cp = skipcomment(tline); 542 if (linestate == LS_START) { 543 if (*cp == '#') { 544 linestate = LS_HASH; 545 cp = skipcomment(cp + 1); 546 } else if (*cp != '\0') 547 linestate = LS_DIRTY; 548 } 549 if (!incomment && linestate == LS_HASH) { 550 keyword = tline + (cp - tline); 551 cp = skipsym(cp); 552 kwlen = cp - keyword; 553 /* no way can we deal with a continuation inside a keyword */ 554 if (strncmp(cp, "\\\n", 2) == 0) 555 Eioccc(); 556 if (strlcmp("ifdef", keyword, kwlen) == 0 || 557 strlcmp("ifndef", keyword, kwlen) == 0) { 558 cp = skipcomment(cp); 559 if ((cursym = findsym(cp)) < 0) 560 retval = LT_IF; 561 else { 562 retval = (keyword[2] == 'n') 563 ? LT_FALSE : LT_TRUE; 564 if (value[cursym] == NULL) 565 retval = (retval == LT_TRUE) 566 ? LT_FALSE : LT_TRUE; 567 if (ignore[cursym]) 568 retval = (retval == LT_TRUE) 569 ? LT_TRUEI : LT_FALSEI; 570 } 571 cp = skipsym(cp); 572 } else if (strlcmp("if", keyword, kwlen) == 0) 573 retval = ifeval(&cp); 574 else if (strlcmp("elif", keyword, kwlen) == 0) 575 retval = ifeval(&cp) - LT_IF + LT_ELIF; 576 else if (strlcmp("else", keyword, kwlen) == 0) 577 retval = LT_ELSE; 578 else if (strlcmp("endif", keyword, kwlen) == 0) 579 retval = LT_ENDIF; 580 else { 581 linestate = LS_DIRTY; 582 retval = LT_PLAIN; 583 } 584 cp = skipcomment(cp); 585 if (*cp != '\0') { 586 linestate = LS_DIRTY; 587 if (retval == LT_TRUE || retval == LT_FALSE || 588 retval == LT_TRUEI || retval == LT_FALSEI) 589 retval = LT_IF; 590 if (retval == LT_ELTRUE || retval == LT_ELFALSE) 591 retval = LT_ELIF; 592 } 593 if (retval != LT_PLAIN && (wascomment || incomment)) { 594 retval += LT_DODGY; 595 if (incomment) 596 linestate = LS_DIRTY; 597 } 598 /* skipcomment should have changed the state */ 599 if (linestate == LS_HASH) 600 abort(); /* bug */ 601 } 602 if (linestate == LS_DIRTY) { 603 while (*cp != '\0') 604 cp = skipcomment(cp + 1); 605 } 606 debug("parser %s comment %s line", 607 comment_name[incomment], linestate_name[linestate]); 608 return (retval); 609 } 610 611 /* 612 * These are the binary operators that are supported by the expression 613 * evaluator. Note that if support for division is added then we also 614 * need short-circuiting booleans because of divide-by-zero. 615 */ 616 static int op_lt(int a, int b) { return (a < b); } 617 static int op_gt(int a, int b) { return (a > b); } 618 static int op_le(int a, int b) { return (a <= b); } 619 static int op_ge(int a, int b) { return (a >= b); } 620 static int op_eq(int a, int b) { return (a == b); } 621 static int op_ne(int a, int b) { return (a != b); } 622 static int op_or(int a, int b) { return (a || b); } 623 static int op_and(int a, int b) { return (a && b); } 624 625 /* 626 * An evaluation function takes three arguments, as follows: (1) a pointer to 627 * an element of the precedence table which lists the operators at the current 628 * level of precedence; (2) a pointer to an integer which will receive the 629 * value of the expression; and (3) a pointer to a char* that points to the 630 * expression to be evaluated and that is updated to the end of the expression 631 * when evaluation is complete. The function returns LT_FALSE if the value of 632 * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the 633 * expression could not be evaluated. 634 */ 635 struct ops; 636 637 typedef Linetype eval_fn(const struct ops *, int *, const char **); 638 639 static eval_fn eval_table, eval_unary; 640 641 /* 642 * The precedence table. Expressions involving binary operators are evaluated 643 * in a table-driven way by eval_table. When it evaluates a subexpression it 644 * calls the inner function with its first argument pointing to the next 645 * element of the table. Innermost expressions have special non-table-driven 646 * handling. 647 */ 648 static const struct ops { 649 eval_fn *inner; 650 struct op { 651 const char *str; 652 int (*fn)(int, int); 653 } op[5]; 654 } eval_ops[] = { 655 { eval_table, { { "||", op_or } } }, 656 { eval_table, { { "&&", op_and } } }, 657 { eval_table, { { "==", op_eq }, 658 { "!=", op_ne } } }, 659 { eval_unary, { { "<=", op_le }, 660 { ">=", op_ge }, 661 { "<", op_lt }, 662 { ">", op_gt } } } 663 }; 664 665 /* 666 * Function for evaluating the innermost parts of expressions, 667 * viz. !expr (expr) defined(symbol) symbol number 668 * We reset the keepthis flag when we find a non-constant subexpression. 669 */ 670 static Linetype 671 eval_unary(const struct ops *ops, int *valp, const char **cpp) 672 { 673 const char *cp; 674 char *ep; 675 int sym; 676 677 cp = skipcomment(*cpp); 678 if (*cp == '!') { 679 debug("eval%d !", ops - eval_ops); 680 cp++; 681 if (eval_unary(ops, valp, &cp) == LT_IF) 682 return (LT_IF); 683 *valp = !*valp; 684 } else if (*cp == '(') { 685 cp++; 686 debug("eval%d (", ops - eval_ops); 687 if (eval_table(eval_ops, valp, &cp) == LT_IF) 688 return (LT_IF); 689 cp = skipcomment(cp); 690 if (*cp++ != ')') 691 return (LT_IF); 692 } else if (isdigit((unsigned char)*cp)) { 693 debug("eval%d number", ops - eval_ops); 694 *valp = strtol(cp, &ep, 0); 695 cp = skipsym(cp); 696 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) { 697 cp = skipcomment(cp+7); 698 debug("eval%d defined", ops - eval_ops); 699 if (*cp++ != '(') 700 return (LT_IF); 701 cp = skipcomment(cp); 702 sym = findsym(cp); 703 if (sym < 0) 704 return (LT_IF); 705 *valp = (value[sym] != NULL); 706 cp = skipsym(cp); 707 cp = skipcomment(cp); 708 if (*cp++ != ')') 709 return (LT_IF); 710 keepthis = false; 711 } else if (!endsym(*cp)) { 712 debug("eval%d symbol", ops - eval_ops); 713 sym = findsym(cp); 714 if (sym < 0) 715 return (LT_IF); 716 if (value[sym] == NULL) 717 *valp = 0; 718 else { 719 *valp = strtol(value[sym], &ep, 0); 720 if (*ep != '\0' || ep == value[sym]) 721 return (LT_IF); 722 } 723 cp = skipsym(cp); 724 keepthis = false; 725 } else { 726 debug("eval%d bad expr", ops - eval_ops); 727 return (LT_IF); 728 } 729 730 *cpp = cp; 731 debug("eval%d = %d", ops - eval_ops, *valp); 732 return (*valp ? LT_TRUE : LT_FALSE); 733 } 734 735 /* 736 * Table-driven evaluation of binary operators. 737 */ 738 static Linetype 739 eval_table(const struct ops *ops, int *valp, const char **cpp) 740 { 741 const struct op *op; 742 const char *cp; 743 int val; 744 745 debug("eval%d", ops - eval_ops); 746 cp = *cpp; 747 if (ops->inner(ops+1, valp, &cp) == LT_IF) 748 return (LT_IF); 749 for (;;) { 750 cp = skipcomment(cp); 751 for (op = ops->op; op->str != NULL; op++) 752 if (strncmp(cp, op->str, strlen(op->str)) == 0) 753 break; 754 if (op->str == NULL) 755 break; 756 cp += strlen(op->str); 757 debug("eval%d %s", ops - eval_ops, op->str); 758 if (ops->inner(ops+1, &val, &cp) == LT_IF) 759 return (LT_IF); 760 *valp = op->fn(*valp, val); 761 } 762 763 *cpp = cp; 764 debug("eval%d = %d", ops - eval_ops, *valp); 765 return (*valp ? LT_TRUE : LT_FALSE); 766 } 767 768 /* 769 * Evaluate the expression on a #if or #elif line. If we can work out 770 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we 771 * return just a generic LT_IF. 772 */ 773 static Linetype 774 ifeval(const char **cpp) 775 { 776 int ret; 777 int val; 778 779 debug("eval %s", *cpp); 780 keepthis = killconsts ? false : true; 781 ret = eval_table(eval_ops, &val, cpp); 782 debug("eval = %d", val); 783 return (keepthis ? LT_IF : ret); 784 } 785 786 /* 787 * Skip over comments, strings, and character literals and stop at the 788 * next character position that is not whitespace. Between calls we keep 789 * the comment state in the global variable incomment, and we also adjust 790 * the global variable linestate when we see a newline. 791 * XXX: doesn't cope with the buffer splitting inside a state transition. 792 */ 793 static const char * 794 skipcomment(const char *cp) 795 { 796 if (text || ignoring[depth]) { 797 for (; isspace((unsigned char)*cp); cp++) 798 if (*cp == '\n') 799 linestate = LS_START; 800 return (cp); 801 } 802 while (*cp != '\0') 803 /* don't reset to LS_START after a line continuation */ 804 if (strncmp(cp, "\\\n", 2) == 0) 805 cp += 2; 806 else switch (incomment) { 807 case NO_COMMENT: 808 if (strncmp(cp, "/\\\n", 3) == 0) { 809 incomment = STARTING_COMMENT; 810 cp += 3; 811 } else if (strncmp(cp, "/*", 2) == 0) { 812 incomment = C_COMMENT; 813 cp += 2; 814 } else if (strncmp(cp, "//", 2) == 0) { 815 incomment = CXX_COMMENT; 816 cp += 2; 817 } else if (strncmp(cp, "\'", 1) == 0) { 818 incomment = CHAR_LITERAL; 819 linestate = LS_DIRTY; 820 cp += 1; 821 } else if (strncmp(cp, "\"", 1) == 0) { 822 incomment = STRING_LITERAL; 823 linestate = LS_DIRTY; 824 cp += 1; 825 } else if (strncmp(cp, "\n", 1) == 0) { 826 linestate = LS_START; 827 cp += 1; 828 } else if (strchr(" \t", *cp) != NULL) { 829 cp += 1; 830 } else 831 return (cp); 832 continue; 833 case CXX_COMMENT: 834 if (strncmp(cp, "\n", 1) == 0) { 835 incomment = NO_COMMENT; 836 linestate = LS_START; 837 } 838 cp += 1; 839 continue; 840 case CHAR_LITERAL: 841 case STRING_LITERAL: 842 if ((incomment == CHAR_LITERAL && cp[0] == '\'') || 843 (incomment == STRING_LITERAL && cp[0] == '\"')) { 844 incomment = NO_COMMENT; 845 cp += 1; 846 } else if (cp[0] == '\\') { 847 if (cp[1] == '\0') 848 cp += 1; 849 else 850 cp += 2; 851 } else if (strncmp(cp, "\n", 1) == 0) { 852 if (incomment == CHAR_LITERAL) 853 error("unterminated char literal"); 854 else 855 error("unterminated string literal"); 856 } else 857 cp += 1; 858 continue; 859 case C_COMMENT: 860 if (strncmp(cp, "*\\\n", 3) == 0) { 861 incomment = FINISHING_COMMENT; 862 cp += 3; 863 } else if (strncmp(cp, "*/", 2) == 0) { 864 incomment = NO_COMMENT; 865 cp += 2; 866 } else 867 cp += 1; 868 continue; 869 case STARTING_COMMENT: 870 if (*cp == '*') { 871 incomment = C_COMMENT; 872 cp += 1; 873 } else if (*cp == '/') { 874 incomment = CXX_COMMENT; 875 cp += 1; 876 } else { 877 incomment = NO_COMMENT; 878 linestate = LS_DIRTY; 879 } 880 continue; 881 case FINISHING_COMMENT: 882 if (*cp == '/') { 883 incomment = NO_COMMENT; 884 cp += 1; 885 } else 886 incomment = C_COMMENT; 887 continue; 888 default: 889 abort(); /* bug */ 890 } 891 return (cp); 892 } 893 894 /* 895 * Skip over an identifier. 896 */ 897 static const char * 898 skipsym(const char *cp) 899 { 900 while (!endsym(*cp)) 901 ++cp; 902 return (cp); 903 } 904 905 /* 906 * Look for the symbol in the symbol table. If is is found, we return 907 * the symbol table index, else we return -1. 908 */ 909 static int 910 findsym(const char *str) 911 { 912 const char *cp; 913 int symind; 914 915 cp = skipsym(str); 916 if (cp == str) 917 return (-1); 918 if (symlist) { 919 printf("%.*s\n", (int)(cp-str), str); 920 /* we don't care about the value of the symbol */ 921 return (0); 922 } 923 for (symind = 0; symind < nsyms; ++symind) { 924 if (strlcmp(symname[symind], str, cp-str) == 0) { 925 debug("findsym %s %s", symname[symind], 926 value[symind] ? value[symind] : ""); 927 return (symind); 928 } 929 } 930 return (-1); 931 } 932 933 /* 934 * Add a symbol to the symbol table. 935 */ 936 static void 937 addsym(bool ignorethis, bool definethis, char *sym) 938 { 939 int symind; 940 char *val; 941 942 symind = findsym(sym); 943 if (symind < 0) { 944 if (nsyms >= MAXSYMS) 945 errx(2, "too many symbols"); 946 symind = nsyms++; 947 } 948 symname[symind] = sym; 949 ignore[symind] = ignorethis; 950 val = sym + (skipsym(sym) - sym); 951 if (definethis) { 952 if (*val == '=') { 953 value[symind] = val+1; 954 *val = '\0'; 955 } else if (*val == '\0') 956 value[symind] = ""; 957 else 958 usage(); 959 } else { 960 if (*val != '\0') 961 usage(); 962 value[symind] = NULL; 963 } 964 } 965 966 /* 967 * Compare s with n characters of t. 968 * The same as strncmp() except that it checks that s[n] == '\0'. 969 */ 970 static int 971 strlcmp(const char *s, const char *t, size_t n) 972 { 973 while (n-- && *t != '\0') 974 if (*s != *t) 975 return ((unsigned char)*s - (unsigned char)*t); 976 else 977 ++s, ++t; 978 return ((unsigned char)*s); 979 } 980 981 /* 982 * Diagnostics. 983 */ 984 static void 985 debug(const char *msg, ...) 986 { 987 va_list ap; 988 989 if (debugging) { 990 va_start(ap, msg); 991 vwarnx(msg, ap); 992 va_end(ap); 993 } 994 } 995 996 static void 997 error(const char *msg) 998 { 999 if (depth == 0) 1000 warnx("%s: %d: %s", filename, linenum, msg); 1001 else 1002 warnx("%s: %d: %s (#if line %d depth %d)", 1003 filename, linenum, msg, stifline[depth], depth); 1004 errx(2, "output may be truncated"); 1005 } 1006