1/*
2 * Copyright (c) 2002 - 2011 Tony Finch <dot@dotat.at>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26/*
27 * unifdef - remove ifdef'ed lines
28 *
29 * This code was derived from software contributed to Berkeley by Dave Yost.
30 * It was rewritten to support ANSI C by Tony Finch. The original version
31 * of unifdef carried the 4-clause BSD copyright licence. None of its code
32 * remains in this version (though some of the names remain) so it now
33 * carries a more liberal licence.
34 *
35 * Wishlist:
36 * provide an option which will append the name of the
37 * appropriate symbol after #else's and #endif's
38 * provide an option which will check symbols after
39 * #else's and #endif's to see that they match their
40 * corresponding #ifdef or #ifndef
41 *
42 * These require better buffer handling, which would also make
43 * it possible to handle all "dodgy" directives correctly.
44 */
45
46#include <sys/types.h>
47#include <sys/stat.h>
48
49#include <ctype.h>
50#include <err.h>
51#include <errno.h>
52#include <stdarg.h>
53#include <stdbool.h>
54#include <stdio.h>
55#include <stdlib.h>
56#include <string.h>
57#include <unistd.h>
58
59const char copyright[] =
60 "@(#) $Version: unifdef-2.5 $\n"
61 "@(#) $Author: Tony Finch (dot@dotat.at) $\n"
62 "@(#) $URL: http://dotat.at/prog/unifdef $\n"
63;
64
65/* types of input lines: */
66typedef enum {
67 LT_TRUEI, /* a true #if with ignore flag */
68 LT_FALSEI, /* a false #if with ignore flag */
69 LT_IF, /* an unknown #if */
70 LT_TRUE, /* a true #if */
71 LT_FALSE, /* a false #if */
72 LT_ELIF, /* an unknown #elif */
73 LT_ELTRUE, /* a true #elif */
74 LT_ELFALSE, /* a false #elif */
75 LT_ELSE, /* #else */
76 LT_ENDIF, /* #endif */
77 LT_DODGY, /* flag: directive is not on one line */
78 LT_DODGY_LAST = LT_DODGY + LT_ENDIF,
79 LT_PLAIN, /* ordinary line */
80 LT_EOF, /* end of file */
81 LT_ERROR, /* unevaluable #if */
82 LT_COUNT
83} Linetype;
84
85static 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", "ERROR"
93};
94
95/* state of #if processing */
96typedef 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
110static 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 */
118typedef 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
128static char const * const comment_name[] = {
129 "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING"
130};
131
132/* state of preprocessor line parser */
133typedef 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
139static 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 * For temporary filenames
158 */
159#define TEMPLATE "unifdef.XXXXXX"
160
161/*
162 * Globals.
163 */
164
165static bool compblank; /* -B: compress blank lines */
166static bool lnblank; /* -b: blank deleted lines */
167static bool complement; /* -c: do the complement */
168static bool debugging; /* -d: debugging reports */
169static bool iocccok; /* -e: fewer IOCCC errors */
170static bool strictlogic; /* -K: keep ambiguous #ifs */
171static bool killconsts; /* -k: eval constant #ifs */
172static bool lnnum; /* -n: add #line directives */
173static bool symlist; /* -s: output symbol list */
174static bool symdepth; /* -S: output symbol depth */
175static bool text; /* -t: this is a text file */
176
177static const char *symname[MAXSYMS]; /* symbol name */
178static const char *value[MAXSYMS]; /* -Dsym=value */
179static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */
180static int nsyms; /* number of symbols */
181
182static FILE *input; /* input file pointer */
183static const char *filename; /* input file name */
184static int linenum; /* current line number */
185static FILE *output; /* output file pointer */
186static const char *ofilename; /* output file name */
187static bool overwriting; /* output overwrites input */
188static char tempname[FILENAME_MAX]; /* used when overwriting */
189
190static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */
191static char *keyword; /* used for editing #elif's */
192
193static const char *newline; /* input file format */
194static const char newline_unix[] = "\n";
195static const char newline_crlf[] = "\r\n";
196
197static Comment_state incomment; /* comment parser state */
198static Line_state linestate; /* #if line parser state */
199static Ifstate ifstate[MAXDEPTH]; /* #if processor state */
200static bool ignoring[MAXDEPTH]; /* ignore comments state */
201static int stifline[MAXDEPTH]; /* start of current #if */
202static int depth; /* current #if nesting */
203static int delcount; /* count of deleted lines */
204static unsigned blankcount; /* count of blank lines */
205static unsigned blankmax; /* maximum recent blankcount */
206static bool constexpr; /* constant #if expression */
207static bool zerosyms = true; /* to format symdepth output */
208static bool firstsym; /* ditto */
209
210static int exitstat; /* program exit status */
211
212static void addsym(bool, bool, char *);
213static void closeout(void);
214static void debug(const char *, ...);
215static void done(void);
216static void error(const char *);
217static int findsym(const char *);
218static void flushline(bool);
219static Linetype parseline(void);
220static Linetype ifeval(const char **);
221static void ignoreoff(void);
222static void ignoreon(void);
223static void keywordedit(const char *);
224static void nest(void);
225static void process(void);
226static const char *skipargs(const char *);
227static const char *skipcomment(const char *);
228static const char *skipsym(const char *);
229static void state(Ifstate);
230static int strlcmp(const char *, const char *, size_t);
231static void unnest(void);
232static void usage(void);
233static void version(void);
234
235#define endsym(c) (!isalnum((unsigned char)c) && c != '_')
236
237/*
238 * The main program.
239 */
240int
241main(int argc, char *argv[])
242{
243 int opt;
244
245 while ((opt = getopt(argc, argv, "i:D:U:I:o:bBcdeKklnsStV")) != -1)
246 switch (opt) {
247 case 'i': /* treat stuff controlled by these symbols as text */
248 /*
249 * For strict backwards-compatibility the U or D
250 * should be immediately after the -i but it doesn't
251 * matter much if we relax that requirement.
252 */
253 opt = *optarg++;
254 if (opt == 'D')
255 addsym(true, true, optarg);
256 else if (opt == 'U')
257 addsym(true, false, optarg);
258 else
259 usage();
260 break;
261 case 'D': /* define a symbol */
262 addsym(false, true, optarg);
263 break;
264 case 'U': /* undef a symbol */
265 addsym(false, false, optarg);
266 break;
267 case 'I': /* no-op for compatibility with cpp */
268 break;
269 case 'b': /* blank deleted lines instead of omitting them */
270 case 'l': /* backwards compatibility */
271 lnblank = true;
272 break;
273 case 'B': /* compress blank lines around removed section */
274 compblank = true;
275 break;
276 case 'c': /* treat -D as -U and vice versa */
277 complement = true;
278 break;
279 case 'd':
280 debugging = true;
281 break;
282 case 'e': /* fewer errors from dodgy lines */
283 iocccok = true;
284 break;
285 case 'K': /* keep ambiguous #ifs */
286 strictlogic = true;
287 break;
288 case 'k': /* process constant #ifs */
289 killconsts = true;
290 break;
291 case 'n': /* add #line directive after deleted lines */
292 lnnum = true;
293 break;
294 case 'o': /* output to a file */
295 ofilename = optarg;
296 break;
297 case 's': /* only output list of symbols that control #ifs */
298 symlist = true;
299 break;
300 case 'S': /* list symbols with their nesting depth */
301 symlist = symdepth = true;
302 break;
303 case 't': /* don't parse C comments */
304 text = true;
305 break;
306 case 'V': /* print version */
307 version();
308 default:
309 usage();
310 }
311 argc -= optind;
312 argv += optind;
313 if (compblank && lnblank)
314 errx(2, "-B and -b are mutually exclusive");
315 if (argc > 1) {
316 errx(2, "can only do one file");
317 } else if (argc == 1 && strcmp(*argv, "-") != 0) {
318 filename = *argv;
319 input = fopen(filename, "rb");
320 if (input == NULL)
321 err(2, "can't open %s", filename);
322 } else {
323 filename = "[stdin]";
324 input = stdin;
325 }
326 if (ofilename == NULL) {
327 ofilename = "[stdout]";
328 output = stdout;
329 } else {
330 struct stat ist, ost;
331 if (stat(ofilename, &ost) == 0 &&
332 fstat(fileno(input), &ist) == 0)
333 overwriting = (ist.st_dev == ost.st_dev
334 && ist.st_ino == ost.st_ino);
335 if (overwriting) {
336 const char *dirsep;
337 int ofd;
338
339 dirsep = strrchr(ofilename, '/');
340 if (dirsep != NULL)
341 snprintf(tempname, sizeof(tempname),
342 "%.*s/" TEMPLATE,
343 (int)(dirsep - ofilename), ofilename);
344 else
345 snprintf(tempname, sizeof(tempname),
346 TEMPLATE);
347 ofd = mkstemp(tempname);
348 if (ofd != -1)
349 output = fdopen(ofd, "wb+");
350 if (output == NULL)
351 err(2, "can't create temporary file");
352 fchmod(ofd, ist.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO));
353 } else {
354 output = fopen(ofilename, "wb");
355 if (output == NULL)
356 err(2, "can't open %s", ofilename);
357 }
358 }
359 process();
360 abort(); /* bug */
361}
362
363static void
364version(void)
365{
366 const char *c = copyright;
367 for (;;) {
368 while (*++c != '$')
369 if (*c == '\0')
370 exit(0);
371 while (*++c != '$')
372 putc(*c, stderr);
373 putc('\n', stderr);
374 }
375}
376
377static void
378usage(void)
379{
380 fprintf(stderr, "usage: unifdef [-bBcdeKknsStV] [-Ipath]"
381 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n");
382 exit(2);
383}
384
385/*
386 * A state transition function alters the global #if processing state
387 * in a particular way. The table below is indexed by the current
388 * processing state and the type of the current line.
389 *
390 * Nesting is handled by keeping a stack of states; some transition
391 * functions increase or decrease the depth. They also maintain the
392 * ignore state on a stack. In some complicated cases they have to
393 * alter the preprocessor directive, as follows.
394 *
395 * When we have processed a group that starts off with a known-false
396 * #if/#elif sequence (which has therefore been deleted) followed by a
397 * #elif that we don't understand and therefore must keep, we edit the
398 * latter into a #if to keep the nesting correct. We use memcpy() to
399 * overwrite the 4 byte token "elif" with "if " without a '\0' byte.
400 *
401 * When we find a true #elif in a group, the following block will
402 * always be kept and the rest of the sequence after the next #elif or
403 * #else will be discarded. We edit the #elif into a #else and the
404 * following directive to #endif since this has the desired behaviour.
405 *
406 * "Dodgy" directives are split across multiple lines, the most common
407 * example being a multi-line comment hanging off the right of the
408 * directive. We can handle them correctly only if there is no change
409 * from printing to dropping (or vice versa) caused by that directive.
410 * If the directive is the first of a group we have a choice between
411 * failing with an error, or passing it through unchanged instead of
412 * evaluating it. The latter is not the default to avoid questions from
413 * users about unifdef unexpectedly leaving behind preprocessor directives.
414 */
415typedef void state_fn(void);
416
417/* report an error */
418static void Eelif (void) { error("Inappropriate #elif"); }
419static void Eelse (void) { error("Inappropriate #else"); }
420static void Eendif(void) { error("Inappropriate #endif"); }
421static void Eeof (void) { error("Premature EOF"); }
422static void Eioccc(void) { error("Obfuscated preprocessor control line"); }
423/* plain line handling */
424static void print (void) { flushline(true); }
425static void drop (void) { flushline(false); }
426/* output lacks group's start line */
427static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); }
428static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); }
429static void Selse (void) { drop(); state(IS_TRUE_ELSE); }
430/* print/pass this block */
431static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); }
432static void Pelse (void) { print(); state(IS_PASS_ELSE); }
433static void Pendif(void) { print(); unnest(); }
434/* discard this block */
435static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); }
436static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); }
437static void Delse (void) { drop(); state(IS_FALSE_ELSE); }
438static void Dendif(void) { drop(); unnest(); }
439/* first line of group */
440static void Fdrop (void) { nest(); Dfalse(); }
441static void Fpass (void) { nest(); Pelif(); }
442static void Ftrue (void) { nest(); Strue(); }
443static void Ffalse(void) { nest(); Sfalse(); }
444/* variable pedantry for obfuscated lines */
445static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); }
446static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); }
447static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); }
448/* ignore comments in this block */
449static void Idrop (void) { Fdrop(); ignoreon(); }
450static void Itrue (void) { Ftrue(); ignoreon(); }
451static void Ifalse(void) { Ffalse(); ignoreon(); }
452/* modify this line */
453static void Mpass (void) { memcpy(keyword, "if ", 4); Pelif(); }
454static void Mtrue (void) { keywordedit("else"); state(IS_TRUE_MIDDLE); }
455static void Melif (void) { keywordedit("endif"); state(IS_FALSE_TRAILER); }
456static void Melse (void) { keywordedit("endif"); state(IS_FALSE_ELSE); }
457
458static state_fn * const trans_table[IS_COUNT][LT_COUNT] = {
459/* IS_OUTSIDE */
460{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif,
461 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif,
462 print, done, abort },
463/* IS_FALSE_PREFIX */
464{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif,
465 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc,
466 drop, Eeof, abort },
467/* IS_TRUE_PREFIX */
468{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif,
469 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
470 print, Eeof, abort },
471/* IS_PASS_MIDDLE */
472{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif,
473 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif,
474 print, Eeof, abort },
475/* IS_FALSE_MIDDLE */
476{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif,
477 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
478 drop, Eeof, abort },
479/* IS_TRUE_MIDDLE */
480{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif,
481 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif,
482 print, Eeof, abort },
483/* IS_PASS_ELSE */
484{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif,
485 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif,
486 print, Eeof, abort },
487/* IS_FALSE_ELSE */
488{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif,
489 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc,
490 drop, Eeof, abort },
491/* IS_TRUE_ELSE */
492{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif,
493 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc,
494 print, Eeof, abort },
495/* IS_FALSE_TRAILER */
496{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif,
497 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc,
498 drop, Eeof, abort }
499/*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF
500 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY)
501 PLAIN EOF ERROR */
502};
503
504/*
505 * State machine utility functions
506 */
507static void
508ignoreoff(void)
509{
510 if (depth == 0)
511 abort(); /* bug */
512 ignoring[depth] = ignoring[depth-1];
513}
514static void
515ignoreon(void)
516{
517 ignoring[depth] = true;
518}
519static void
520keywordedit(const char *replacement)
521{
522 snprintf(keyword, tline + sizeof(tline) - keyword,
523 "%s%s", replacement, newline);
524 print();
525}
526static void
527nest(void)
528{
529 if (depth > MAXDEPTH-1)
530 abort(); /* bug */
531 if (depth == MAXDEPTH-1)
532 error("Too many levels of nesting");
533 depth += 1;
534 stifline[depth] = linenum;
535}
536static void
537unnest(void)
538{
539 if (depth == 0)
540 abort(); /* bug */
541 depth -= 1;
542}
543static void
544state(Ifstate is)
545{
546 ifstate[depth] = is;
547}
548
549/*
550 * Write a line to the output or not, according to command line options.
551 */
552static void
553flushline(bool keep)
554{
555 if (symlist)
556 return;
557 if (keep ^ complement) {
558 bool blankline = tline[strspn(tline, " \t\r\n")] == '\0';
559 if (blankline && compblank && blankcount != blankmax) {
560 delcount += 1;
561 blankcount += 1;
562 } else {
563 if (lnnum && delcount > 0)
564 printf("#line %d%s", linenum, newline);
565 fputs(tline, output);
566 delcount = 0;
567 blankmax = blankcount = blankline ? blankcount + 1 : 0;
568 }
569 } else {
570 if (lnblank)
571 fputs(newline, output);
572 exitstat = 1;
573 delcount += 1;
574 blankcount = 0;
575 }
576 if (debugging)
577 fflush(output);
578}
579
580/*
581 * The driver for the state machine.
582 */
583static void
584process(void)
585{
586 /* When compressing blank lines, act as if the file
587 is preceded by a large number of blank lines. */
588 blankmax = blankcount = 1000;
589 for (;;) {
590 Linetype lineval = parseline();
591 trans_table[ifstate[depth]][lineval]();
592 debug("process line %d %s -> %s depth %d",
593 linenum, linetype_name[lineval],
594 ifstate_name[ifstate[depth]], depth);
595 }
596}
597
598/*
599 * Flush the output and handle errors.
600 */
601static void
602closeout(void)
603{
604 if (symdepth && !zerosyms)
605 printf("\n");
606 if (fclose(output) == EOF) {
607 warn("couldn't write to %s", ofilename);
608 if (overwriting) {
609 unlink(tempname);
610 errx(2, "%s unchanged", filename);
611 } else {
612 exit(2);
613 }
614 }
615}
616
617/*
618 * Clean up and exit.
619 */
620static void
621done(void)
622{
623 if (incomment)
624 error("EOF in comment");
625 closeout();
626 if (overwriting && rename(tempname, ofilename) == -1) {
627 warn("couldn't rename temporary file");
628 unlink(tempname);
629 errx(2, "%s unchanged", ofilename);
630 }
631 exit(exitstat);
632}
633
634/*
635 * Parse a line and determine its type. We keep the preprocessor line
636 * parser state between calls in the global variable linestate, with
637 * help from skipcomment().
638 */
639static Linetype
640parseline(void)
641{
642 const char *cp;
643 int cursym;
644 int kwlen;
645 Linetype retval;
646 Comment_state wascomment;
647
648 linenum++;
649 if (fgets(tline, MAXLINE, input) == NULL)
650 return (LT_EOF);
651 if (newline == NULL) {
652 if (strrchr(tline, '\n') == strrchr(tline, '\r') + 1)
653 newline = newline_crlf;
654 else
655 newline = newline_unix;
656 }
657 retval = LT_PLAIN;
658 wascomment = incomment;
659 cp = skipcomment(tline);
660 if (linestate == LS_START) {
661 if (*cp == '#') {
662 linestate = LS_HASH;
663 firstsym = true;
664 cp = skipcomment(cp + 1);
665 } else if (*cp != '\0')
666 linestate = LS_DIRTY;
667 }
668 if (!incomment && linestate == LS_HASH) {
669 keyword = tline + (cp - tline);
670 cp = skipsym(cp);
671 kwlen = cp - keyword;
672 /* no way can we deal with a continuation inside a keyword */
673 if (strncmp(cp, "\\\r\n", 3) == 0 ||
674 strncmp(cp, "\\\n", 2) == 0)
675 Eioccc();
676 if (strlcmp("ifdef", keyword, kwlen) == 0 ||
677 strlcmp("ifndef", keyword, kwlen) == 0) {
678 cp = skipcomment(cp);
679 if ((cursym = findsym(cp)) < 0)
680 retval = LT_IF;
681 else {
682 retval = (keyword[2] == 'n')
683 ? LT_FALSE : LT_TRUE;
684 if (value[cursym] == NULL)
685 retval = (retval == LT_TRUE)
686 ? LT_FALSE : LT_TRUE;
687 if (ignore[cursym])
688 retval = (retval == LT_TRUE)
689 ? LT_TRUEI : LT_FALSEI;
690 }
691 cp = skipsym(cp);
692 } else if (strlcmp("if", keyword, kwlen) == 0)
693 retval = ifeval(&cp);
694 else if (strlcmp("elif", keyword, kwlen) == 0)
695 retval = ifeval(&cp) - LT_IF + LT_ELIF;
696 else if (strlcmp("else", keyword, kwlen) == 0)
697 retval = LT_ELSE;
698 else if (strlcmp("endif", keyword, kwlen) == 0)
699 retval = LT_ENDIF;
700 else {
701 linestate = LS_DIRTY;
702 retval = LT_PLAIN;
703 }
704 cp = skipcomment(cp);
705 if (*cp != '\0') {
706 linestate = LS_DIRTY;
707 if (retval == LT_TRUE || retval == LT_FALSE ||
708 retval == LT_TRUEI || retval == LT_FALSEI)
709 retval = LT_IF;
710 if (retval == LT_ELTRUE || retval == LT_ELFALSE)
711 retval = LT_ELIF;
712 }
713 if (retval != LT_PLAIN && (wascomment || incomment)) {
714 retval += LT_DODGY;
715 if (incomment)
716 linestate = LS_DIRTY;
717 }
718 /* skipcomment normally changes the state, except
719 if the last line of the file lacks a newline, or
720 if there is too much whitespace in a directive */
721 if (linestate == LS_HASH) {
722 size_t len = cp - tline;
723 if (fgets(tline + len, MAXLINE - len, input) == NULL) {
724 /* append the missing newline */
725 strcpy(tline + len, newline);
726 cp += strlen(newline);
727 linestate = LS_START;
728 } else {
729 linestate = LS_DIRTY;
730 }
731 }
732 }
733 if (linestate == LS_DIRTY) {
734 while (*cp != '\0')
735 cp = skipcomment(cp + 1);
736 }
737 debug("parser line %d state %s comment %s line", linenum,
738 comment_name[incomment], linestate_name[linestate]);
739 return (retval);
740}
741
742/*
743 * These are the binary operators that are supported by the expression
744 * evaluator.
745 */
746static Linetype op_strict(int *p, int v, Linetype at, Linetype bt) {
747 if(at == LT_IF || bt == LT_IF) return (LT_IF);
748 return (*p = v, v ? LT_TRUE : LT_FALSE);
749}
750static Linetype op_lt(int *p, Linetype at, int a, Linetype bt, int b) {
751 return op_strict(p, a < b, at, bt);
752}
753static Linetype op_gt(int *p, Linetype at, int a, Linetype bt, int b) {
754 return op_strict(p, a > b, at, bt);
755}
756static Linetype op_le(int *p, Linetype at, int a, Linetype bt, int b) {
757 return op_strict(p, a <= b, at, bt);
758}
759static Linetype op_ge(int *p, Linetype at, int a, Linetype bt, int b) {
760 return op_strict(p, a >= b, at, bt);
761}
762static Linetype op_eq(int *p, Linetype at, int a, Linetype bt, int b) {
763 return op_strict(p, a == b, at, bt);
764}
765static Linetype op_ne(int *p, Linetype at, int a, Linetype bt, int b) {
766 return op_strict(p, a != b, at, bt);
767}
768static Linetype op_or(int *p, Linetype at, int a, Linetype bt, int b) {
769 if (!strictlogic && (at == LT_TRUE || bt == LT_TRUE))
770 return (*p = 1, LT_TRUE);
771 return op_strict(p, a || b, at, bt);
772}
773static Linetype op_and(int *p, Linetype at, int a, Linetype bt, int b) {
774 if (!strictlogic && (at == LT_FALSE || bt == LT_FALSE))
775 return (*p = 0, LT_FALSE);
776 return op_strict(p, a && b, at, bt);
777}
778
779/*
780 * An evaluation function takes three arguments, as follows: (1) a pointer to
781 * an element of the precedence table which lists the operators at the current
782 * level of precedence; (2) a pointer to an integer which will receive the
783 * value of the expression; and (3) a pointer to a char* that points to the
784 * expression to be evaluated and that is updated to the end of the expression
785 * when evaluation is complete. The function returns LT_FALSE if the value of
786 * the expression is zero, LT_TRUE if it is non-zero, LT_IF if the expression
787 * depends on an unknown symbol, or LT_ERROR if there is a parse failure.
788 */
789struct ops;
790
791typedef Linetype eval_fn(const struct ops *, int *, const char **);
792
793static eval_fn eval_table, eval_unary;
794
795/*
796 * The precedence table. Expressions involving binary operators are evaluated
797 * in a table-driven way by eval_table. When it evaluates a subexpression it
798 * calls the inner function with its first argument pointing to the next
799 * element of the table. Innermost expressions have special non-table-driven
800 * handling.
801 */
802static const struct ops {
803 eval_fn *inner;
804 struct op {
805 const char *str;
806 Linetype (*fn)(int *, Linetype, int, Linetype, int);
807 } op[5];
808} eval_ops[] = {
809 { eval_table, { { "||", op_or } } },
810 { eval_table, { { "&&", op_and } } },
811 { eval_table, { { "==", op_eq },
812 { "!=", op_ne } } },
813 { eval_unary, { { "<=", op_le },
814 { ">=", op_ge },
815 { "<", op_lt },
816 { ">", op_gt } } }
817};
818
819/*
820 * Function for evaluating the innermost parts of expressions,
821 * viz. !expr (expr) number defined(symbol) symbol
822 * We reset the constexpr flag in the last two cases.
823 */
824static Linetype
825eval_unary(const struct ops *ops, int *valp, const char **cpp)
826{
827 const char *cp;
828 char *ep;
829 int sym;
830 bool defparen;
831 Linetype lt;
832
833 cp = skipcomment(*cpp);
834 if (*cp == '!') {
835 debug("eval%d !", ops - eval_ops);
836 cp++;
837 lt = eval_unary(ops, valp, &cp);
838 if (lt == LT_ERROR)
839 return (LT_ERROR);
840 if (lt != LT_IF) {
841 *valp = !*valp;
842 lt = *valp ? LT_TRUE : LT_FALSE;
843 }
844 } else if (*cp == '(') {
845 cp++;
846 debug("eval%d (", ops - eval_ops);
847 lt = eval_table(eval_ops, valp, &cp);
848 if (lt == LT_ERROR)
849 return (LT_ERROR);
850 cp = skipcomment(cp);
851 if (*cp++ != ')')
852 return (LT_ERROR);
853 } else if (isdigit((unsigned char)*cp)) {
854 debug("eval%d number", ops - eval_ops);
855 *valp = strtol(cp, &ep, 0);
856 if (ep == cp)
857 return (LT_ERROR);
858 lt = *valp ? LT_TRUE : LT_FALSE;
859 cp = skipsym(cp);
860 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) {
861 cp = skipcomment(cp+7);
862 debug("eval%d defined", ops - eval_ops);
863 if (*cp == '(') {
864 cp = skipcomment(cp+1);
865 defparen = true;
866 } else {
867 defparen = false;
868 }
869 sym = findsym(cp);
870 if (sym < 0) {
871 lt = LT_IF;
872 } else {
873 *valp = (value[sym] != NULL);
874 lt = *valp ? LT_TRUE : LT_FALSE;
875 }
876 cp = skipsym(cp);
877 cp = skipcomment(cp);
878 if (defparen && *cp++ != ')')
879 return (LT_ERROR);
880 constexpr = false;
881 } else if (!endsym(*cp)) {
882 debug("eval%d symbol", ops - eval_ops);
883 sym = findsym(cp);
884 cp = skipsym(cp);
885 if (sym < 0) {
886 lt = LT_IF;
887 cp = skipargs(cp);
888 } else if (value[sym] == NULL) {
889 *valp = 0;
890 lt = LT_FALSE;
891 } else {
892 *valp = strtol(value[sym], &ep, 0);
893 if (*ep != '\0' || ep == value[sym])
894 return (LT_ERROR);
895 lt = *valp ? LT_TRUE : LT_FALSE;
896 cp = skipargs(cp);
897 }
898 constexpr = false;
899 } else {
900 debug("eval%d bad expr", ops - eval_ops);
901 return (LT_ERROR);
902 }
903
904 *cpp = cp;
905 debug("eval%d = %d", ops - eval_ops, *valp);
906 return (lt);
907}
908
909/*
910 * Table-driven evaluation of binary operators.
911 */
912static Linetype
913eval_table(const struct ops *ops, int *valp, const char **cpp)
914{
915 const struct op *op;
916 const char *cp;
917 int val;
918 Linetype lt, rt;
919
920 debug("eval%d", ops - eval_ops);
921 cp = *cpp;
922 lt = ops->inner(ops+1, valp, &cp);
923 if (lt == LT_ERROR)
924 return (LT_ERROR);
925 for (;;) {
926 cp = skipcomment(cp);
927 for (op = ops->op; op->str != NULL; op++)
928 if (strncmp(cp, op->str, strlen(op->str)) == 0)
929 break;
930 if (op->str == NULL)
931 break;
932 cp += strlen(op->str);
933 debug("eval%d %s", ops - eval_ops, op->str);
934 rt = ops->inner(ops+1, &val, &cp);
935 if (rt == LT_ERROR)
936 return (LT_ERROR);
937 lt = op->fn(valp, lt, *valp, rt, val);
938 }
939
940 *cpp = cp;
941 debug("eval%d = %d", ops - eval_ops, *valp);
942 debug("eval%d lt = %s", ops - eval_ops, linetype_name[lt]);
943 return (lt);
944}
945
946/*
947 * Evaluate the expression on a #if or #elif line. If we can work out
948 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we
949 * return just a generic LT_IF.
950 */
951static Linetype
952ifeval(const char **cpp)
953{
954 int ret;
955 int val = 0;
956
957 debug("eval %s", *cpp);
958 constexpr = killconsts ? false : true;
959 ret = eval_table(eval_ops, &val, cpp);
960 debug("eval = %d", val);
961 return (constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
962}
963
964/*
965 * Skip over comments, strings, and character literals and stop at the
966 * next character position that is not whitespace. Between calls we keep
967 * the comment state in the global variable incomment, and we also adjust
968 * the global variable linestate when we see a newline.
969 * XXX: doesn't cope with the buffer splitting inside a state transition.
970 */
971static const char *
972skipcomment(const char *cp)
973{
974 if (text || ignoring[depth]) {
975 for (; isspace((unsigned char)*cp); cp++)
976 if (*cp == '\n')
977 linestate = LS_START;
978 return (cp);
979 }
980 while (*cp != '\0')
981 /* don't reset to LS_START after a line continuation */
982 if (strncmp(cp, "\\\r\n", 3) == 0)
983 cp += 3;
984 else if (strncmp(cp, "\\\n", 2) == 0)
985 cp += 2;
986 else switch (incomment) {
987 case NO_COMMENT:
988 if (strncmp(cp, "/\\\r\n", 4) == 0) {
989 incomment = STARTING_COMMENT;
990 cp += 4;
991 } else if (strncmp(cp, "/\\\n", 3) == 0) {
992 incomment = STARTING_COMMENT;
993 cp += 3;
994 } else if (strncmp(cp, "/*", 2) == 0) {
995 incomment = C_COMMENT;
996 cp += 2;
997 } else if (strncmp(cp, "//", 2) == 0) {
998 incomment = CXX_COMMENT;
999 cp += 2;
1000 } else if (strncmp(cp, "\'", 1) == 0) {
1001 incomment = CHAR_LITERAL;
1002 linestate = LS_DIRTY;
1003 cp += 1;
1004 } else if (strncmp(cp, "\"", 1) == 0) {
1005 incomment = STRING_LITERAL;
1006 linestate = LS_DIRTY;
1007 cp += 1;
1008 } else if (strncmp(cp, "\n", 1) == 0) {
1009 linestate = LS_START;
1010 cp += 1;
1011 } else if (strchr(" \r\t", *cp) != NULL) {
1012 cp += 1;
1013 } else
1014 return (cp);
1015 continue;
1016 case CXX_COMMENT:
1017 if (strncmp(cp, "\n", 1) == 0) {
1018 incomment = NO_COMMENT;
1019 linestate = LS_START;
1020 }
1021 cp += 1;
1022 continue;
1023 case CHAR_LITERAL:
1024 case STRING_LITERAL:
1025 if ((incomment == CHAR_LITERAL && cp[0] == '\'') ||
1026 (incomment == STRING_LITERAL && cp[0] == '\"')) {
1027 incomment = NO_COMMENT;
1028 cp += 1;
1029 } else if (cp[0] == '\\') {
1030 if (cp[1] == '\0')
1031 cp += 1;
1032 else
1033 cp += 2;
1034 } else if (strncmp(cp, "\n", 1) == 0) {
1035 if (incomment == CHAR_LITERAL)
1036 error("unterminated char literal");
1037 else
1038 error("unterminated string literal");
1039 } else
1040 cp += 1;
1041 continue;
1042 case C_COMMENT:
1043 if (strncmp(cp, "*\\\r\n", 4) == 0) {
1044 incomment = FINISHING_COMMENT;
1045 cp += 4;
1046 } else if (strncmp(cp, "*\\\n", 3) == 0) {
1047 incomment = FINISHING_COMMENT;
1048 cp += 3;
1049 } else if (strncmp(cp, "*/", 2) == 0) {
1050 incomment = NO_COMMENT;
1051 cp += 2;
1052 } else
1053 cp += 1;
1054 continue;
1055 case STARTING_COMMENT:
1056 if (*cp == '*') {
1057 incomment = C_COMMENT;
1058 cp += 1;
1059 } else if (*cp == '/') {
1060 incomment = CXX_COMMENT;
1061 cp += 1;
1062 } else {
1063 incomment = NO_COMMENT;
1064 linestate = LS_DIRTY;
1065 }
1066 continue;
1067 case FINISHING_COMMENT:
1068 if (*cp == '/') {
1069 incomment = NO_COMMENT;
1070 cp += 1;
1071 } else
1072 incomment = C_COMMENT;
1073 continue;
1074 default:
1075 abort(); /* bug */
1076 }
1077 return (cp);
1078}
1079
1080/*
1081 * Skip macro arguments.
1082 */
1083static const char *
1084skipargs(const char *cp)
1085{
1086 const char *ocp = cp;
1087 int level = 0;
1088 cp = skipcomment(cp);
1089 if (*cp != '(')
1090 return (cp);
1091 do {
1092 if (*cp == '(')
1093 level++;
1094 if (*cp == ')')
1095 level--;
1096 cp = skipcomment(cp+1);
1097 } while (level != 0 && *cp != '\0');
1098 if (level == 0)
1099 return (cp);
1100 else
1101 /* Rewind and re-detect the syntax error later. */
1102 return (ocp);
1103}
1104
1105/*
1106 * Skip over an identifier.
1107 */
1108static const char *
1109skipsym(const char *cp)
1110{
1111 while (!endsym(*cp))
1112 ++cp;
1113 return (cp);
1114}
1115
1116/*
1117 * Look for the symbol in the symbol table. If it is found, we return
1118 * the symbol table index, else we return -1.
1119 */
1120static int
1121findsym(const char *str)
1122{
1123 const char *cp;
1124 int symind;
1125
1126 cp = skipsym(str);
1127 if (cp == str)
1128 return (-1);
1129 if (symlist) {
1130 if (symdepth && firstsym)
1131 printf("%s%3d", zerosyms ? "" : "\n", depth);
1132 firstsym = zerosyms = false;
1133 printf("%s%.*s%s",
1134 symdepth ? " " : "",
1135 (int)(cp-str), str,
1136 symdepth ? "" : "\n");
1137 /* we don't care about the value of the symbol */
1138 return (0);
1139 }
1140 for (symind = 0; symind < nsyms; ++symind) {
1141 if (strlcmp(symname[symind], str, cp-str) == 0) {
1142 debug("findsym %s %s", symname[symind],
1143 value[symind] ? value[symind] : "");
1144 return (symind);
1145 }
1146 }
1147 return (-1);
1148}
1149
1150/*
1151 * Add a symbol to the symbol table.
1152 */
1153static void
1154addsym(bool ignorethis, bool definethis, char *sym)
1155{
1156 int symind;
1157 char *val;
1158
1159 symind = findsym(sym);
1160 if (symind < 0) {
1161 if (nsyms >= MAXSYMS)
1162 errx(2, "too many symbols");
1163 symind = nsyms++;
1164 }
1165 symname[symind] = sym;
1166 ignore[symind] = ignorethis;
1167 val = sym + (skipsym(sym) - sym);
1168 if (definethis) {
1169 if (*val == '=') {
1170 value[symind] = val+1;
1171 *val = '\0';
1172 } else if (*val == '\0')
1173 value[symind] = "1";
1174 else
1175 usage();
1176 } else {
1177 if (*val != '\0')
1178 usage();
1179 value[symind] = NULL;
1180 }
1181 debug("addsym %s=%s", symname[symind],
1182 value[symind] ? value[symind] : "undef");
1183}
1184
1185/*
1186 * Compare s with n characters of t.
1187 * The same as strncmp() except that it checks that s[n] == '\0'.
1188 */
1189static int
1190strlcmp(const char *s, const char *t, size_t n)
1191{
1192 while (n-- && *t != '\0')
1193 if (*s != *t)
1194 return ((unsigned char)*s - (unsigned char)*t);
1195 else
1196 ++s, ++t;
1197 return ((unsigned char)*s);
1198}
1199
1200/*
1201 * Diagnostics.
1202 */
1203static void
1204debug(const char *msg, ...)
1205{
1206 va_list ap;
1207
1208 if (debugging) {
1209 va_start(ap, msg);
1210 vwarnx(msg, ap);
1211 va_end(ap);
1212 }
1213}
1214
1215static void
1216error(const char *msg)
1217{
1218 if (depth == 0)
1219 warnx("%s: %d: %s", filename, linenum, msg);
1220 else
1221 warnx("%s: %d: %s (#if line %d depth %d)",
1222 filename, linenum, msg, stifline[depth], depth);
1223 closeout();
1224 errx(2, "output may be truncated");
1225}
1226