1 /* 2 * Copyright (c) 1985, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Dave Yost. Support for #if and #elif was added by Tony Finch. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#) Copyright (c) 1985, 1993 The Regents of the University of California. All rights reserved. 37 * @(#)unifdef.c 8.1 (Berkeley) 6/6/93 38 * $NetBSD: unifdef.c,v 1.8 2000/07/03 02:51:36 matt Exp $ 39 * $dotat: things/unifdef.c,v 1.148 2003/01/20 12:05:41 fanf2 Exp $ 40 * $FreeBSD: src/usr.bin/unifdef/unifdef.c,v 1.4.2.5 2003/01/29 21:46:39 fanf Exp $ 41 * $DragonFly: src/usr.bin/unifdef/unifdef.c,v 1.2 2003/06/17 04:29:33 dillon Exp $ 42 */ 43 44 #include <sys/cdefs.h> 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 * indicate 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 Eelif (void) { error("Inappropriate #elif"); } 335 static void Eelse (void) { error("Inappropriate #else"); } 336 static void Eendif(void) { error("Inappropriate #endif"); } 337 static void Eeof (void) { error("Premature EOF"); } 338 static void Eioccc(void) { error("Obfuscated preprocessor control line"); } 339 /* plain line handling */ 340 static void print (void) { flushline(true); } 341 static void drop (void) { flushline(false); } 342 /* output lacks group's start line */ 343 static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); } 344 static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); } 345 static void Selse (void) { drop(); state(IS_TRUE_ELSE); } 346 /* print/pass this block */ 347 static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); } 348 static void Pelse (void) { print(); state(IS_PASS_ELSE); } 349 static void Pendif(void) { print(); --depth; } 350 /* discard this block */ 351 static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); } 352 static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); } 353 static void Delse (void) { drop(); state(IS_FALSE_ELSE); } 354 static void Dendif(void) { drop(); --depth; } 355 /* first line of group */ 356 static void Fdrop (void) { nest(); Dfalse(); } 357 static void Fpass (void) { nest(); Pelif(); } 358 static void Ftrue (void) { nest(); Strue(); } 359 static void Ffalse(void) { nest(); Sfalse(); } 360 /* variable pedantry for obfuscated lines */ 361 static void Oiffy (void) { if (iocccok) Fpass(); else Eioccc(); ignoreon(); } 362 static void Oif (void) { if (iocccok) Fpass(); else Eioccc(); } 363 static void Oelif (void) { if (iocccok) Pelif(); else Eioccc(); } 364 /* ignore comments in this block */ 365 static void Idrop (void) { Fdrop(); ignoreon(); } 366 static void Itrue (void) { Ftrue(); ignoreon(); } 367 static void Ifalse(void) { Ffalse(); ignoreon(); } 368 /* edit this line */ 369 static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); } 370 static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); } 371 static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); } 372 static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); } 373 374 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = { 375 /* IS_OUTSIDE */ 376 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif, 377 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif, 378 print, NULL }, 379 /* IS_FALSE_PREFIX */ 380 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif, 381 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc, 382 drop, Eeof }, 383 /* IS_TRUE_PREFIX */ 384 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif, 385 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 386 print, Eeof }, 387 /* IS_PASS_MIDDLE */ 388 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif, 389 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif, 390 print, Eeof }, 391 /* IS_FALSE_MIDDLE */ 392 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif, 393 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc, 394 drop, Eeof }, 395 /* IS_TRUE_MIDDLE */ 396 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif, 397 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif, 398 print, Eeof }, 399 /* IS_PASS_ELSE */ 400 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif, 401 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif, 402 print, Eeof }, 403 /* IS_FALSE_ELSE */ 404 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif, 405 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc, 406 drop, Eeof }, 407 /* IS_TRUE_ELSE */ 408 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif, 409 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc, 410 print, Eeof }, 411 /* IS_FALSE_TRAILER */ 412 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif, 413 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc, 414 drop, Eeof } 415 /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF 416 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY) 417 PLAIN EOF */ 418 }; 419 420 /* 421 * State machine utility functions 422 */ 423 static void 424 ignoreoff(void) 425 { 426 ignoring[depth] = ignoring[depth-1]; 427 } 428 static void 429 ignoreon(void) 430 { 431 ignoring[depth] = true; 432 } 433 static void 434 keywordedit(const char *replacement) 435 { 436 strlcpy(keyword, replacement, tline + sizeof(tline) - keyword); 437 print(); 438 } 439 static void 440 nest(void) 441 { 442 depth += 1; 443 if (depth >= MAXDEPTH) 444 error("Too many levels of nesting"); 445 stifline[depth] = linenum; 446 } 447 static void 448 state(Ifstate is) 449 { 450 ifstate[depth] = is; 451 } 452 453 /* 454 * Write a line to the output or not, according to command line options. 455 */ 456 static void 457 flushline(bool keep) 458 { 459 if (symlist) 460 return; 461 if (keep ^ complement) 462 fputs(tline, stdout); 463 else { 464 if (lnblank) 465 putc('\n', stdout); 466 exitstat = 1; 467 } 468 } 469 470 /* 471 * The driver for the state machine. 472 */ 473 static void 474 process(void) 475 { 476 Linetype lineval; 477 state_fn *trans; 478 479 for (;;) { 480 linenum++; 481 lineval = getline(); 482 trans = trans_table[ifstate[depth]][lineval]; 483 if (trans == NULL) 484 break; 485 trans(); 486 debug("process %s -> %s depth %d", 487 linetype_name[lineval], 488 ifstate_name[ifstate[depth]], depth); 489 } 490 if (incomment) 491 error("EOF in comment"); 492 } 493 494 /* 495 * Parse a line and determine its type. We keep the preprocessor line 496 * parser state between calls in a global variable. 497 */ 498 static Linetype 499 getline(void) 500 { 501 const char *cp; 502 int cursym; 503 int kwlen; 504 Linetype retval; 505 Comment_state wascomment; 506 507 if (fgets(tline, MAXLINE, input) == NULL) 508 return (LT_EOF); 509 retval = LT_PLAIN; 510 wascomment = incomment; 511 cp = skipcomment(tline); 512 if (linestate == LS_START) { 513 if (*cp == '#') { 514 linestate = LS_HASH; 515 cp = skipcomment(cp + 1); 516 } else if (*cp != '\0') 517 linestate = LS_DIRTY; 518 } 519 if (!incomment && linestate == LS_HASH) { 520 keyword = tline + (cp - tline); 521 cp = skipsym(cp); 522 kwlen = cp - keyword; 523 /* no way can we deal with a continuation inside a keyword */ 524 if (strncmp(cp, "\\\n", 2) == 0) 525 Eioccc(); 526 if (strlcmp("ifdef", keyword, kwlen) == 0 || 527 strlcmp("ifndef", keyword, kwlen) == 0) { 528 cp = skipcomment(cp); 529 if ((cursym = findsym(cp)) < 0) 530 retval = LT_IF; 531 else { 532 retval = (keyword[2] == 'n') 533 ? LT_FALSE : LT_TRUE; 534 if (value[cursym] == NULL) 535 retval = (retval == LT_TRUE) 536 ? LT_FALSE : LT_TRUE; 537 if (ignore[cursym]) 538 retval = (retval == LT_TRUE) 539 ? LT_TRUEI : LT_FALSEI; 540 } 541 cp = skipsym(cp); 542 } else if (strlcmp("if", keyword, kwlen) == 0) 543 retval = ifeval(&cp); 544 else if (strlcmp("elif", keyword, kwlen) == 0) 545 retval = ifeval(&cp) - LT_IF + LT_ELIF; 546 else if (strlcmp("else", keyword, kwlen) == 0) 547 retval = LT_ELSE; 548 else if (strlcmp("endif", keyword, kwlen) == 0) 549 retval = LT_ENDIF; 550 else { 551 linestate = LS_DIRTY; 552 retval = LT_PLAIN; 553 } 554 cp = skipcomment(cp); 555 if (*cp != '\0') { 556 linestate = LS_DIRTY; 557 if (retval == LT_TRUE || retval == LT_FALSE || 558 retval == LT_TRUEI || retval == LT_FALSEI) 559 retval = LT_IF; 560 if (retval == LT_ELTRUE || retval == LT_ELFALSE) 561 retval = LT_ELIF; 562 } 563 if (retval != LT_PLAIN && (wascomment || incomment)) { 564 retval += LT_DODGY; 565 if (incomment) 566 linestate = LS_DIRTY; 567 } 568 /* skipcomment should have changed the state */ 569 if (linestate == LS_HASH) 570 abort(); /* bug */ 571 } 572 if (linestate == LS_DIRTY) { 573 while (*cp != '\0') 574 cp = skipcomment(cp + 1); 575 } 576 debug("parser %s comment %s line", 577 comment_name[incomment], linestate_name[linestate]); 578 return (retval); 579 } 580 581 /* 582 * These are the operators that are supported by the expression evaluator. 583 */ 584 static int op_lt(int a, int b) { return (a < b); } 585 static int op_gt(int a, int b) { return (a > b); } 586 static int op_le(int a, int b) { return (a <= b); } 587 static int op_ge(int a, int b) { return (a >= b); } 588 static int op_eq(int a, int b) { return (a == b); } 589 static int op_ne(int a, int b) { return (a != b); } 590 static int op_or(int a, int b) { return (a || b); } 591 static int op_and(int a, int b) { return (a && b); } 592 593 /* 594 * An evaluation function takes three arguments, as follows: (1) a pointer to 595 * an element of the precedence table which lists the operators at the current 596 * level of precedence; (2) a pointer to an integer which will receive the 597 * value of the expression; and (3) a pointer to a char* that points to the 598 * expression to be evaluated and that is updated to the end of the expression 599 * when evaluation is complete. The function returns LT_FALSE if the value of 600 * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the 601 * expression could not be evaluated. 602 */ 603 struct ops; 604 605 typedef Linetype eval_fn(const struct ops *, int *, const char **); 606 607 static eval_fn eval_table, eval_unary; 608 609 /* 610 * The precedence table. Expressions involving binary operators are evaluated 611 * in a table-driven way by eval_table. When it evaluates a subexpression it 612 * calls the inner function with its first argument pointing to the next 613 * element of the table. Innermost expressions have special non-table-driven 614 * handling. 615 */ 616 static const struct ops { 617 eval_fn *inner; 618 struct op { 619 const char *str; 620 int (*fn)(int, int); 621 } op[5]; 622 } eval_ops[] = { 623 { eval_table, { { "||", op_or } } }, 624 { eval_table, { { "&&", op_and } } }, 625 { eval_table, { { "==", op_eq }, 626 { "!=", op_ne } } }, 627 { eval_unary, { { "<=", op_le }, 628 { ">=", op_ge }, 629 { "<", op_lt }, 630 { ">", op_gt } } } 631 }; 632 633 /* 634 * Function for evaluating the innermost parts of expressions, 635 * viz. !expr (expr) defined(symbol) symbol number 636 * We reset the keepthis flag when we find a non-constant subexpression. 637 */ 638 static Linetype 639 eval_unary(const struct ops *ops, int *valp, const char **cpp) 640 { 641 const char *cp; 642 char *ep; 643 int sym; 644 645 cp = skipcomment(*cpp); 646 if (*cp == '!') { 647 debug("eval%d !", ops - eval_ops); 648 cp++; 649 if (eval_unary(ops, valp, &cp) == LT_IF) 650 return (LT_IF); 651 *valp = !*valp; 652 } else if (*cp == '(') { 653 cp++; 654 debug("eval%d (", ops - eval_ops); 655 if (eval_table(eval_ops, valp, &cp) == LT_IF) 656 return (LT_IF); 657 cp = skipcomment(cp); 658 if (*cp++ != ')') 659 return (LT_IF); 660 } else if (isdigit((unsigned char)*cp)) { 661 debug("eval%d number", ops - eval_ops); 662 *valp = strtol(cp, &ep, 0); 663 cp = skipsym(cp); 664 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) { 665 cp = skipcomment(cp+7); 666 debug("eval%d defined", ops - eval_ops); 667 if (*cp++ != '(') 668 return (LT_IF); 669 cp = skipcomment(cp); 670 sym = findsym(cp); 671 if (sym < 0 && !symlist) 672 return (LT_IF); 673 *valp = (value[sym] != NULL); 674 cp = skipsym(cp); 675 cp = skipcomment(cp); 676 if (*cp++ != ')') 677 return (LT_IF); 678 keepthis = false; 679 } else if (!endsym(*cp)) { 680 debug("eval%d symbol", ops - eval_ops); 681 sym = findsym(cp); 682 if (sym < 0 && !symlist) 683 return (LT_IF); 684 if (value[sym] == NULL) 685 *valp = 0; 686 else { 687 *valp = strtol(value[sym], &ep, 0); 688 if (*ep != '\0' || ep == value[sym]) 689 return (LT_IF); 690 } 691 cp = skipsym(cp); 692 keepthis = false; 693 } else 694 return (LT_IF); 695 696 *cpp = cp; 697 debug("eval%d = %d", ops - eval_ops, *valp); 698 return (*valp ? LT_TRUE : LT_FALSE); 699 } 700 701 /* 702 * Table-driven evaluation of binary operators. 703 */ 704 static Linetype 705 eval_table(const struct ops *ops, int *valp, const char **cpp) 706 { 707 const struct op *op; 708 const char *cp; 709 int val; 710 711 debug("eval%d", ops - eval_ops); 712 cp = *cpp; 713 if (ops->inner(ops+1, valp, &cp) == LT_IF) 714 return (LT_IF); 715 for (;;) { 716 cp = skipcomment(cp); 717 for (op = ops->op; op->str != NULL; op++) 718 if (strncmp(cp, op->str, strlen(op->str)) == 0) 719 break; 720 if (op->str == NULL) 721 break; 722 cp += strlen(op->str); 723 debug("eval%d %s", ops - eval_ops, op->str); 724 if (ops->inner(ops+1, &val, &cp) == LT_IF) 725 return (LT_IF); 726 *valp = op->fn(*valp, val); 727 } 728 729 *cpp = cp; 730 debug("eval%d = %d", ops - eval_ops, *valp); 731 return (*valp ? LT_TRUE : LT_FALSE); 732 } 733 734 /* 735 * Evaluate the expression on a #if or #elif line. If we can work out 736 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we 737 * return just a generic LT_IF. 738 */ 739 static Linetype 740 ifeval(const char **cpp) 741 { 742 int ret; 743 int val; 744 745 debug("eval %s", *cpp); 746 keepthis = killconsts ? false : true; 747 ret = eval_table(eval_ops, &val, cpp); 748 return (keepthis ? LT_IF : ret); 749 } 750 751 /* 752 * Skip over comments and stop at the next character position that is 753 * not whitespace. Between calls we keep the comment state in a global 754 * variable, and we also make a note when we get a proper end-of-line. 755 * XXX: doesn't cope with the buffer splitting inside a state transition. 756 */ 757 static const char * 758 skipcomment(const char *cp) 759 { 760 if (text || ignoring[depth]) { 761 while (isspace((unsigned char)*cp)) 762 cp += 1; 763 return (cp); 764 } 765 while (*cp != '\0') 766 if (strncmp(cp, "\\\n", 2) == 0) 767 cp += 2; 768 else switch (incomment) { 769 case NO_COMMENT: 770 if (strncmp(cp, "/\\\n", 3) == 0) { 771 incomment = STARTING_COMMENT; 772 cp += 3; 773 } else if (strncmp(cp, "/*", 2) == 0) { 774 incomment = C_COMMENT; 775 cp += 2; 776 } else if (strncmp(cp, "//", 2) == 0) { 777 incomment = CXX_COMMENT; 778 cp += 2; 779 } else if (strncmp(cp, "\n", 1) == 0) { 780 linestate = LS_START; 781 cp += 1; 782 } else if (strchr(" \t", *cp) != NULL) { 783 cp += 1; 784 } else 785 return (cp); 786 continue; 787 case CXX_COMMENT: 788 if (strncmp(cp, "\n", 1) == 0) { 789 incomment = NO_COMMENT; 790 linestate = LS_START; 791 } 792 cp += 1; 793 continue; 794 case C_COMMENT: 795 if (strncmp(cp, "*\\\n", 3) == 0) { 796 incomment = FINISHING_COMMENT; 797 cp += 3; 798 } else if (strncmp(cp, "*/", 2) == 0) { 799 incomment = NO_COMMENT; 800 cp += 2; 801 } else 802 cp += 1; 803 continue; 804 case STARTING_COMMENT: 805 if (*cp == '*') { 806 incomment = C_COMMENT; 807 cp += 1; 808 } else if (*cp == '/') { 809 incomment = CXX_COMMENT; 810 cp += 1; 811 } else { 812 incomment = NO_COMMENT; 813 linestate = LS_DIRTY; 814 } 815 continue; 816 case FINISHING_COMMENT: 817 if (*cp == '/') { 818 incomment = NO_COMMENT; 819 cp += 1; 820 } else 821 incomment = C_COMMENT; 822 continue; 823 default: 824 /* bug */ 825 abort(); 826 } 827 return (cp); 828 } 829 830 /* 831 * Skip over an identifier. 832 */ 833 static const char * 834 skipsym(const char *cp) 835 { 836 while (!endsym(*cp)) 837 ++cp; 838 return (cp); 839 } 840 841 /* 842 * Look for the symbol in the symbol table. If is is found, we return 843 * the symbol table index, else we return -1. 844 */ 845 static int 846 findsym(const char *str) 847 { 848 const char *cp; 849 int symind; 850 851 cp = skipsym(str); 852 if (cp == str) 853 return (-1); 854 if (symlist) 855 printf("%.*s\n", (int)(cp-str), str); 856 for (symind = 0; symind < nsyms; ++symind) { 857 if (strlcmp(symname[symind], str, cp-str) == 0) { 858 debug("findsym %s %s", symname[symind], 859 value[symind] ? value[symind] : ""); 860 return (symind); 861 } 862 } 863 return (-1); 864 } 865 866 /* 867 * Add a symbol to the symbol table. 868 */ 869 static void 870 addsym(bool ignorethis, bool definethis, char *sym) 871 { 872 int symind; 873 char *val; 874 875 symind = findsym(sym); 876 if (symind < 0) { 877 if (nsyms >= MAXSYMS) 878 errx(2, "too many symbols"); 879 symind = nsyms++; 880 } 881 symname[symind] = sym; 882 ignore[symind] = ignorethis; 883 val = sym + (skipsym(sym) - sym); 884 if (definethis) { 885 if (*val == '=') { 886 value[symind] = val+1; 887 *val = '\0'; 888 } else if (*val == '\0') 889 value[symind] = ""; 890 else 891 usage(); 892 } else { 893 if (*val != '\0') 894 usage(); 895 value[symind] = NULL; 896 } 897 } 898 899 /* 900 * Compare s with n characters of t. 901 * The same as strncmp() except that it checks that s[n] == '\0'. 902 */ 903 static int 904 strlcmp(const char *s, const char *t, size_t n) 905 { 906 while (n-- && *t != '\0') 907 if (*s != *t) 908 return ((unsigned char)*s - (unsigned char)*t); 909 else 910 ++s, ++t; 911 return ((unsigned char)*s); 912 } 913 914 /* 915 * Diagnostics. 916 */ 917 static void 918 debug(const char *msg, ...) 919 { 920 va_list ap; 921 922 if (debugging) { 923 va_start(ap, msg); 924 vwarnx(msg, ap); 925 va_end(ap); 926 } 927 } 928 929 static void 930 error(const char *msg) 931 { 932 if (depth == 0) 933 warnx("%s: %d: %s", filename, linenum, msg); 934 else 935 warnx("%s: %d: %s (#if line %d depth %d)", 936 filename, linenum, msg, stifline[depth], depth); 937 errx(2, "output may be truncated"); 938 } 939