xref: /freebsd/usr.bin/diff3/diff3.c (revision 349cc55c9796c4596a5b9904cd3281af295f878f)
1 /*	$OpenBSD: diff3prog.c,v 1.11 2009/10/27 23:59:37 deraadt Exp $	*/
2 
3 /*
4  * Copyright (C) Caldera International Inc.  2001-2002.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code and documentation must retain the above
11  *    copyright notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed or owned by Caldera
18  *	International, Inc.
19  * 4. Neither the name of Caldera International, Inc. nor the names of other
20  *    contributors may be used to endorse or promote products derived from
21  *    this software without specific prior written permission.
22  *
23  * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
24  * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT,
28  * INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
32  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
33  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 /*-
37  * Copyright (c) 1991, 1993
38  *	The Regents of the University of California.  All rights reserved.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 3. Neither the name of the University nor the names of its contributors
49  *    may be used to endorse or promote products derived from this software
50  *    without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62  * SUCH DAMAGE.
63  *
64  *	@(#)diff3.c	8.1 (Berkeley) 6/6/93
65  */
66 
67 #if 0
68 #ifndef lint
69 static char sccsid[] = "@(#)diff3.c	8.1 (Berkeley) 6/6/93";
70 #endif
71 #endif /* not lint */
72 #include <sys/cdefs.h>
73 __FBSDID("$FreeBSD$");
74 
75 #include <sys/capsicum.h>
76 #include <sys/procdesc.h>
77 #include <sys/types.h>
78 #include <sys/event.h>
79 #include <sys/wait.h>
80 
81 #include <capsicum_helpers.h>
82 #include <ctype.h>
83 #include <err.h>
84 #include <getopt.h>
85 #include <stdio.h>
86 #include <stdlib.h>
87 #include <limits.h>
88 #include <inttypes.h>
89 #include <string.h>
90 #include <unistd.h>
91 
92 
93 /*
94  * "from" is first in range of changed lines; "to" is last+1
95  * from=to=line after point of insertion for added lines.
96  */
97 struct range {
98 	int from;
99 	int to;
100 };
101 
102 struct diff {
103 #define DIFF_TYPE2 2
104 #define DIFF_TYPE3 3
105 	int type;
106 #if DEBUG
107 	char *line;
108 #endif	/* DEBUG */
109 
110 	/* Ranges as lines */
111 	struct range old;
112 	struct range new;
113 };
114 
115 static size_t szchanges;
116 
117 static struct diff *d13;
118 static struct diff *d23;
119 /*
120  * "de" is used to gather editing scripts.  These are later spewed out in
121  * reverse order.  Its first element must be all zero, the "old" and "new"
122  * components of "de" contain line positions. Array overlap indicates which
123  * sections in "de" correspond to lines that are different in all three files.
124  */
125 static struct diff *de;
126 static char *overlap;
127 static int  overlapcnt;
128 static FILE *fp[3];
129 static int cline[3];		/* # of the last-read line in each file (0-2) */
130 /*
131  * The latest known correspondence between line numbers of the 3 files
132  * is stored in last[1-3];
133  */
134 static int last[4];
135 static int Aflag, eflag, iflag, mflag, Tflag;
136 static int oflag;		/* indicates whether to mark overlaps (-E or -X) */
137 static int strip_cr;
138 static char *f1mark, *f2mark, *f3mark;
139 static const char *oldmark = "<<<<<<<";
140 static const char *orgmark = "|||||||";
141 static const char *newmark = ">>>>>>>";
142 
143 static bool duplicate(struct range *, struct range *);
144 static int edit(struct diff *, bool, int, int);
145 static char *getchange(FILE *);
146 static char *get_line(FILE *, size_t *);
147 static int readin(int fd, struct diff **);
148 static int skip(int, int, const char *);
149 static void change(int, struct range *, bool);
150 static void keep(int, struct range *);
151 static void merge(int, int);
152 static void prange(struct range *, bool);
153 static void repos(int);
154 static void edscript(int) __dead2;
155 static void Ascript(int) __dead2;
156 static void mergescript(int) __dead2;
157 static void increase(void);
158 static void usage(void) __dead2;
159 static void printrange(FILE *, struct range *);
160 
161 enum {
162 	DIFFPROG_OPT,
163 	STRIPCR_OPT,
164 };
165 
166 #define DIFF_PATH "/usr/bin/diff"
167 
168 #define OPTIONS "3aAeEiL:mTxX"
169 static struct option longopts[] = {
170 	{ "ed",			no_argument,		NULL,	'e' },
171 	{ "show-overlap",	no_argument,		NULL,	'E' },
172 	{ "overlap-only",	no_argument,		NULL,	'x' },
173 	{ "initial-tab",	no_argument,		NULL,	'T' },
174 	{ "text",		no_argument,		NULL,	'a' },
175 	{ "strip-trailing-cr",	no_argument,		NULL,	STRIPCR_OPT },
176 	{ "show-all",		no_argument,		NULL,	'A' },
177 	{ "easy-only",		no_argument,		NULL,	'3' },
178 	{ "merge",		no_argument,		NULL,	'm' },
179 	{ "label",		required_argument,	NULL,	'L' },
180 	{ "diff-program",	required_argument,	NULL,	DIFFPROG_OPT },
181 };
182 
183 static void
184 usage(void)
185 {
186 	fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L label1] [-L label2] "
187 	    "[-L label3] file1 file2 file3\n");
188 	exit(2);
189 }
190 
191 static int
192 readin(int fd, struct diff **dd)
193 {
194 	int a, b, c, d;
195 	size_t i;
196 	char kind, *p;
197 	FILE *f;
198 
199 	f = fdopen(fd, "r");
200 	if (f == NULL)
201 		err(2, "fdopen");
202 	for (i = 0; (p = getchange(f)); i++) {
203 #if DEBUG
204 		(*dd)[i].line = strdup(p);
205 #endif	/* DEBUG */
206 
207 		if (i >= szchanges - 1)
208 			increase();
209 		a = b = (int)strtoimax(p, &p, 10);
210 		if (*p == ',') {
211 			p++;
212 			b = (int)strtoimax(p, &p, 10);
213 		}
214 		kind = *p++;
215 		c = d = (int)strtoimax(p, &p, 10);
216 		if (*p == ',') {
217 			p++;
218 			d = (int)strtoimax(p, &p, 10);
219 		}
220 		if (kind == 'a')
221 			a++;
222 		if (kind == 'd')
223 			c++;
224 		b++;
225 		d++;
226 		(*dd)[i].old.from = a;
227 		(*dd)[i].old.to = b;
228 		(*dd)[i].new.from = c;
229 		(*dd)[i].new.to = d;
230 	}
231 	if (i) {
232 		(*dd)[i].old.from = (*dd)[i - 1].old.to;
233 		(*dd)[i].new.from = (*dd)[i - 1].new.to;
234 	}
235 	fclose(f);
236 	return (i);
237 }
238 
239 static int
240 diffexec(const char *diffprog, char **diffargv, int fd[])
241 {
242 	int pd;
243 
244 	switch (pdfork(&pd, PD_CLOEXEC)) {
245 	case 0:
246 		close(fd[0]);
247 		if (dup2(fd[1], STDOUT_FILENO) == -1)
248 			err(2, "child could not duplicate descriptor");
249 		close(fd[1]);
250 		execvp(diffprog, diffargv);
251 		err(2, "could not execute diff: %s", diffprog);
252 		break;
253 	case -1:
254 		err(2, "could not fork");
255 		break;
256 	}
257 	close(fd[1]);
258 	return (pd);
259 }
260 
261 static char *
262 getchange(FILE *b)
263 {
264 	char *line;
265 
266 	while ((line = get_line(b, NULL))) {
267 		if (isdigit((unsigned char)line[0]))
268 			return (line);
269 	}
270 	return (NULL);
271 }
272 
273 
274 static char *
275 get_line(FILE *b, size_t *n)
276 {
277 	ssize_t len;
278 	static char *buf = NULL;
279 	static size_t bufsize = 0;
280 
281 	if ((len = getline(&buf, &bufsize, b)) < 0)
282 		return (NULL);
283 
284 	if (strip_cr && len >= 2 && strcmp("\r\n", &(buf[len - 2])) == 0) {
285 		buf[len - 2] = '\n';
286 		buf[len - 1] = '\0';
287 		len--;
288 	}
289 
290 	if (n != NULL)
291 		*n = len;
292 
293 	return (buf);
294 }
295 
296 static void
297 merge(int m1, int m2)
298 {
299 	struct diff *d1, *d2, *d3;
300 	int j, t1, t2;
301 	bool dup = false;
302 
303 	d1 = d13;
304 	d2 = d23;
305 	j = 0;
306 
307 	while ((t1 = d1 < d13 + m1) | (t2 = d2 < d23 + m2)) {
308 		/* first file is different from the others */
309 		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
310 			/* stuff peculiar to 1st file */
311 			if (eflag == 0) {
312 				printf("====1\n");
313 				change(1, &d1->old, false);
314 				keep(2, &d1->new);
315 				change(3, &d1->new, false);
316 			}
317 			d1++;
318 			continue;
319 		}
320 		/* second file is different from others */
321 		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
322 			if (eflag == 0) {
323 				printf("====2\n");
324 				keep(1, &d2->new);
325 				change(3, &d2->new, false);
326 				change(2, &d2->old, false);
327 			} else if (Aflag || mflag) {
328 				// XXX-THJ: What does it mean for the second file to differ?
329 				j = edit(d2, dup, j, DIFF_TYPE2);
330 			}
331 			d2++;
332 			continue;
333 		}
334 		/*
335 		 * Merge overlapping changes in first file
336 		 * this happens after extension (see below).
337 		 */
338 		if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
339 			d1[1].old.from = d1->old.from;
340 			d1[1].new.from = d1->new.from;
341 			d1++;
342 			continue;
343 		}
344 
345 		/* merge overlapping changes in second */
346 		if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
347 			d2[1].old.from = d2->old.from;
348 			d2[1].new.from = d2->new.from;
349 			d2++;
350 			continue;
351 		}
352 		/* stuff peculiar to third file or different in all */
353 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
354 			dup = duplicate(&d1->old, &d2->old);
355 			/*
356 			 * dup = 0 means all files differ
357 			 * dup = 1 means files 1 and 2 identical
358 			 */
359 			if (eflag == 0) {
360 				printf("====%s\n", dup ? "3" : "");
361 				change(1, &d1->old, dup);
362 				change(2, &d2->old, false);
363 				d3 = d1->old.to > d1->old.from ? d1 : d2;
364 				change(3, &d3->new, false);
365 			} else {
366 				j = edit(d1, dup, j, DIFF_TYPE3);
367 			}
368 			dup = false;
369 			d1++;
370 			d2++;
371 			continue;
372 		}
373 		/*
374 		 * Overlapping changes from file 1 and 2; extend changes
375 		 * appropriately to make them coincide.
376 		 */
377 		if (d1->new.from < d2->new.from) {
378 			d2->old.from -= d2->new.from - d1->new.from;
379 			d2->new.from = d1->new.from;
380 		} else if (d2->new.from < d1->new.from) {
381 			d1->old.from -= d1->new.from - d2->new.from;
382 			d1->new.from = d2->new.from;
383 		}
384 		if (d1->new.to > d2->new.to) {
385 			d2->old.to += d1->new.to - d2->new.to;
386 			d2->new.to = d1->new.to;
387 		} else if (d2->new.to > d1->new.to) {
388 			d1->old.to += d2->new.to - d1->new.to;
389 			d1->new.to = d2->new.to;
390 		}
391 	}
392 
393 	if (mflag)
394 		mergescript(j);
395 	else if (Aflag)
396 		Ascript(j);
397 	else if (eflag)
398 		edscript(j);
399 }
400 
401 /*
402  * The range of lines rold.from thru rold.to in file i is to be changed.
403  * It is to be printed only if it does not duplicate something to be
404  * printed later.
405  */
406 static void
407 change(int i, struct range *rold, bool dup)
408 {
409 
410 	printf("%d:", i);
411 	last[i] = rold->to;
412 	prange(rold, false);
413 	if (dup)
414 		return;
415 	i--;
416 	skip(i, rold->from, NULL);
417 	skip(i, rold->to, "  ");
418 }
419 
420 /*
421  * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or
422  * n1.
423  */
424 static void
425 prange(struct range *rold, bool delete)
426 {
427 
428 	if (rold->to <= rold->from)
429 		printf("%da\n", rold->from - 1);
430 	else {
431 		printf("%d", rold->from);
432 		if (rold->to > rold->from + 1)
433 			printf(",%d", rold->to - 1);
434 		if (delete)
435 			printf("d\n");
436 		else
437 			printf("c\n");
438 	}
439 }
440 
441 /*
442  * No difference was reported by diff between file 1 (or 2) and file 3,
443  * and an artificial dummy difference (trange) must be ginned up to
444  * correspond to the change reported in the other file.
445  */
446 static void
447 keep(int i, struct range *rnew)
448 {
449 	int delta;
450 	struct range trange;
451 
452 	delta = last[3] - last[i];
453 	trange.from = rnew->from - delta;
454 	trange.to = rnew->to - delta;
455 	change(i, &trange, true);
456 }
457 
458 /*
459  * skip to just before line number from in file "i".  If "pr" is non-NULL,
460  * print all skipped stuff with string pr as a prefix.
461  */
462 static int
463 skip(int i, int from, const char *pr)
464 {
465 	size_t j, n;
466 	char *line;
467 
468 	for (n = 0; cline[i] < from - 1; n += j) {
469 		if ((line = get_line(fp[i], &j)) == NULL)
470 			errx(EXIT_FAILURE, "logic error");
471 		if (pr != NULL)
472 			printf("%s%s", Tflag == 1 ? "\t" : pr, line);
473 		cline[i]++;
474 	}
475 	return ((int) n);
476 }
477 
478 /*
479  * Return 1 or 0 according as the old range (in file 1) contains exactly
480  * the same data as the new range (in file 2).
481  */
482 static bool
483 duplicate(struct range *r1, struct range *r2)
484 {
485 	int c, d;
486 	int nchar;
487 	int nline;
488 
489 	if (r1->to-r1->from != r2->to-r2->from)
490 		return (0);
491 	skip(0, r1->from, NULL);
492 	skip(1, r2->from, NULL);
493 	nchar = 0;
494 	for (nline = 0; nline < r1->to - r1->from; nline++) {
495 		do {
496 			c = getc(fp[0]);
497 			d = getc(fp[1]);
498 			if (c == -1 && d == -1)
499 				break;
500 			if (c == -1 || d == -1)
501 				errx(EXIT_FAILURE, "logic error");
502 			nchar++;
503 			if (c != d) {
504 				repos(nchar);
505 				return (0);
506 			}
507 		} while (c != '\n');
508 	}
509 	repos(nchar);
510 	return (1);
511 }
512 
513 static void
514 repos(int nchar)
515 {
516 	int i;
517 
518 	for (i = 0; i < 2; i++)
519 		(void)fseek(fp[i], (long)-nchar, SEEK_CUR);
520 }
521 
522 /*
523  * collect an editing script for later regurgitation
524  */
525 static int
526 edit(struct diff *diff, bool dup, int j, int difftype)
527 {
528 
529 	if (((dup + 1) & eflag) == 0)
530 		return (j);
531 	j++;
532 	overlap[j] = !dup;
533 	if (!dup)
534 		overlapcnt++;
535 
536 	de[j].type = difftype;
537 #if DEBUG
538 	de[j].line = diff->line;
539 #endif	/* DEBUG */
540 
541 	de[j].old.from = diff->old.from;
542 	de[j].old.to = diff->old.to;
543 	de[j].new.from = diff->new.from;
544 	de[j].new.to = diff->new.to;
545 	return (j);
546 }
547 
548 static void
549 printrange(FILE *p, struct range *r)
550 {
551 	char *line = NULL;
552 	size_t len = 0;
553 	int i = 1;
554 	ssize_t rlen = 0;
555 
556 	/* We haven't been asked to print anything */
557 	if (r->from == r->to)
558 		return;
559 
560 	if (r->from > r->to)
561 			errx(EXIT_FAILURE, "invalid print range");
562 
563 	/*
564 	 * XXX-THJ: We read through all of the file for each range printed.
565 	 * This duplicates work and will probably impact performance on large
566 	 * files with lots of ranges.
567 	 */
568 	fseek(p, 0L, SEEK_SET);
569 	while ((rlen = getline(&line, &len, p)) > 0) {
570 		if (i >= r->from)
571 			printf("%s", line);
572 		if (++i > r->to - 1)
573 			break;
574 	}
575 	free(line);
576 }
577 
578 /* regurgitate */
579 static void
580 edscript(int n)
581 {
582 	bool delete;
583 
584 	for (; n > 0; n--) {
585 		delete = (de[n].new.from == de[n].new.to);
586 		if (!oflag || !overlap[n]) {
587 			prange(&de[n].old, delete);
588 		} else {
589 			printf("%da\n", de[n].old.to - 1);
590 			printf("=======\n");
591 		}
592 		printrange(fp[2], &de[n].new);
593 		if (!oflag || !overlap[n]) {
594 			if (!delete)
595 				printf(".\n");
596 		} else {
597 			printf("%s %s\n.\n", newmark, f3mark);
598 			printf("%da\n%s %s\n.\n", de[n].old.from - 1,
599 				oldmark, f1mark);
600 		}
601 	}
602 	if (iflag)
603 		printf("w\nq\n");
604 
605 	exit(eflag == 0 ? overlapcnt : 0);
606 }
607 
608 /*
609  * Output an edit script to turn mine into yours, when there is a conflict
610  * between the 3 files bracket the changes. Regurgitate the diffs in reverse
611  * order to allow the ed script to track down where the lines are as changes
612  * are made.
613  */
614 static void
615 Ascript(int n)
616 {
617 	int startmark;
618 	bool deletenew;
619 	bool deleteold;
620 
621 	for (; n > 0; n--) {
622 
623 		deletenew = (de[n].new.from == de[n].new.to);
624 		deleteold = (de[n].old.from == de[n].old.to);
625 		startmark = de[n].old.from + (de[n].old.to - de[n].old.from) - 1;
626 
627 		if (de[n].type == DIFF_TYPE2) {
628 			if (!oflag || !overlap[n]) {
629 				prange(&de[n].old, deletenew);
630 				printrange(fp[2], &de[n].new);
631 			} else {
632 				startmark = de[n].new.from +
633 					(de[n].new.to - de[n].new.from);
634 
635 				if (!deletenew)
636 					startmark--;
637 
638 				printf("%da\n", startmark);
639 				printf("%s %s\n", newmark, f3mark);
640 
641 				printf(".\n");
642 
643 				printf("%da\n", startmark -
644 					(de[n].new.to - de[n].new.from));
645 				printf("%s %s\n", oldmark, f2mark);
646 				if (!deleteold)
647 					printrange(fp[1], &de[n].old);
648 				printf("=======\n.\n");
649 			}
650 
651 		} else if (de[n].type == DIFF_TYPE3) {
652 			if (!oflag || !overlap[n]) {
653 				prange(&de[n].old, deletenew);
654 				printrange(fp[2], &de[n].new);
655 			} else {
656 				printf("%da\n", startmark);
657 				printf("%s %s\n", orgmark, f2mark);
658 
659 				if (deleteold) {
660 					struct range r;
661 					r.from = de[n].old.from-1;
662 					r.to = de[n].new.to;
663 					printrange(fp[1], &r);
664 				} else
665 					printrange(fp[1], &de[n].old);
666 
667 				printf("=======\n");
668 				printrange(fp[2], &de[n].new);
669 			}
670 
671 			if (!oflag || !overlap[n]) {
672 				if (!deletenew)
673 					printf(".\n");
674 			} else {
675 				printf("%s %s\n.\n", newmark, f3mark);
676 
677 				/*
678 				 * Go to the start of the conflict in original
679 				 * file and append lines
680 				 */
681 				printf("%da\n%s %s\n.\n",
682 					startmark - (de[n].old.to - de[n].old.from),
683 					oldmark, f1mark);
684 			}
685 		}
686 	}
687 	if (iflag)
688 		printf("w\nq\n");
689 
690 	exit(overlapcnt > 0);
691 }
692 
693 /*
694  * Output the merged file directly (don't generate an ed script). When
695  * regurgitating diffs we need to walk forward through the file and print any
696  * inbetween lines.
697  */
698 static void
699 mergescript(int i)
700 {
701 	struct range r;
702 	int n;
703 
704 	r.from = 1;
705 	r.to = 1;
706 
707 	for (n = 1; n < i+1; n++) {
708 		/* print any lines leading up to here */
709 		r.to = de[n].old.from;
710 		printrange(fp[0], &r);
711 
712 		if (de[n].type == DIFF_TYPE2) {
713 			printf("%s %s\n", oldmark, f2mark);
714 			printrange(fp[1], &de[n].old);
715 			printf("=======\n");
716 			printrange(fp[2], &de[n].new);
717 			printf("%s %s\n", newmark, f3mark);
718 		} else if (de[n].type == DIFF_TYPE3) {
719 			if (!oflag || !overlap[n]) {
720 				printrange(fp[2], &de[n].new);
721 			} else {
722 
723 				printf("%s %s\n", oldmark, f1mark);
724 				printrange(fp[0], &de[n].old);
725 
726 				printf("%s %s\n", orgmark, f2mark);
727 				if (de[n].old.from == de[n].old.to) {
728 					struct range or;
729 					or.from = de[n].old.from -1;
730 					or.to = de[n].new.to;
731 					printrange(fp[1], &or);
732 				} else
733 					printrange(fp[1], &de[n].old);
734 
735 				printf("=======\n");
736 
737 				printrange(fp[2], &de[n].new);
738 				printf("%s %s\n", newmark, f3mark);
739 			}
740 		}
741 
742 		if (de[n].old.from == de[n].old.to)
743 			r.from = de[n].new.to;
744 		else
745 			r.from = de[n].old.to;
746 	}
747 	/*
748 	 * Print from the final range to the end of 'myfile'. Any deletions or
749 	 * additions to this file should have been handled by now.
750 	 *
751 	 * If the ranges are the same we need to rewind a line.
752 	 * If the new range is 0 length (from == to), we need to use the old
753 	 * range.
754 	 */
755 	if ((de[n-1].old.from == de[n-1].new.from) &&
756 		(de[n-1].old.to == de[n-1].new.to))
757 		r.from--;
758 	else if (de[n-1].new.from == de[n-1].new.to)
759 		r.from = de[n-1].old.from;
760 
761 	/*
762 	 * If the range is a 3 way merge then we need to skip a line in the
763 	 * trailing output.
764 	 */
765 	if (de[n-1].type == DIFF_TYPE3)
766 		r.from++;
767 
768 	r.to = INT_MAX;
769 	printrange(fp[0], &r);
770 	exit(overlapcnt > 0);
771 }
772 
773 static void
774 increase(void)
775 {
776 	struct diff *p;
777 	char *q;
778 	size_t newsz, incr;
779 
780 	/* are the memset(3) calls needed? */
781 	newsz = szchanges == 0 ? 64 : 2 * szchanges;
782 	incr = newsz - szchanges;
783 
784 	p = reallocarray(d13, newsz, sizeof(struct diff));
785 	if (p == NULL)
786 		err(1, NULL);
787 	memset(p + szchanges, 0, incr * sizeof(struct diff));
788 	d13 = p;
789 	p = reallocarray(d23, newsz, sizeof(struct diff));
790 	if (p == NULL)
791 		err(1, NULL);
792 	memset(p + szchanges, 0, incr * sizeof(struct diff));
793 	d23 = p;
794 	p = reallocarray(de, newsz, sizeof(struct diff));
795 	if (p == NULL)
796 		err(1, NULL);
797 	memset(p + szchanges, 0, incr * sizeof(struct diff));
798 	de = p;
799 	q = reallocarray(overlap, newsz, sizeof(char));
800 	if (q == NULL)
801 		err(1, NULL);
802 	memset(q + szchanges, 0, incr * sizeof(char));
803 	overlap = q;
804 	szchanges = newsz;
805 }
806 
807 
808 int
809 main(int argc, char **argv)
810 {
811 	int ch, nblabels, status, m, n, kq, nke, nleft, i;
812 	char *labels[] = { NULL, NULL, NULL };
813 	const char *diffprog = DIFF_PATH;
814 	char *file1, *file2, *file3;
815 	char *diffargv[7];
816 	int diffargc = 0;
817 	int fd13[2], fd23[2];
818 	int pd13, pd23;
819 	cap_rights_t rights_ro;
820 	struct kevent *e;
821 
822 	nblabels = 0;
823 	eflag = 0;
824 	oflag = 0;
825 	diffargv[diffargc++] = __DECONST(char *, diffprog);
826 	while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
827 		switch (ch) {
828 		case '3':
829 			eflag = 2;
830 			break;
831 		case 'a':
832 			diffargv[diffargc++] = __DECONST(char *, "-a");
833 			break;
834 		case 'A':
835 			Aflag = 1;
836 			break;
837 		case 'e':
838 			eflag = 3;
839 			break;
840 		case 'E':
841 			eflag = 3;
842 			oflag = 1;
843 			break;
844 		case 'i':
845 			iflag = 1;
846 			break;
847 		case 'L':
848 			oflag = 1;
849 			if (nblabels >= 3)
850 				errx(2, "too many file label options");
851 			labels[nblabels++] = optarg;
852 			break;
853 		case 'm':
854 			Aflag = 1;
855 			oflag = 1;
856 			mflag = 1;
857 			break;
858 		case 'T':
859 			Tflag = 1;
860 			break;
861 		case 'x':
862 			eflag = 1;
863 			break;
864 		case 'X':
865 			oflag = 1;
866 			eflag = 1;
867 			break;
868 		case DIFFPROG_OPT:
869 			diffprog = optarg;
870 			break;
871 		case STRIPCR_OPT:
872 			strip_cr = 1;
873 			diffargv[diffargc++] = __DECONST(char *, "--strip-trailing-cr");
874 			break;
875 		}
876 	}
877 	argc -= optind;
878 	argv += optind;
879 
880 	if (Aflag) {
881 		eflag = 3;
882 		oflag = 1;
883 	}
884 
885 	if (argc != 3)
886 		usage();
887 
888 	if (caph_limit_stdio() == -1)
889 		err(2, "unable to limit stdio");
890 
891 	cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
892 
893 	kq = kqueue();
894 	if (kq == -1)
895 		err(2, "kqueue");
896 
897 	e = malloc(2 * sizeof(struct kevent));
898 	if (e == NULL)
899 		err(2, "malloc");
900 
901 	/* TODO stdio */
902 	file1 = argv[0];
903 	file2 = argv[1];
904 	file3 = argv[2];
905 
906 	if (oflag) {
907 		asprintf(&f1mark, "%s",
908 		    labels[0] != NULL ? labels[0] : file1);
909 		if (f1mark == NULL)
910 			err(2, "asprintf");
911 		asprintf(&f2mark, "%s",
912 		    labels[1] != NULL ? labels[1] : file2);
913 		if (f2mark == NULL)
914 			err(2, "asprintf");
915 		asprintf(&f3mark, "%s",
916 		    labels[2] != NULL ? labels[2] : file3);
917 		if (f3mark == NULL)
918 			err(2, "asprintf");
919 	}
920 	fp[0] = fopen(file1, "r");
921 	if (fp[0] == NULL)
922 		err(2, "Can't open %s", file1);
923 	if (caph_rights_limit(fileno(fp[0]), &rights_ro) < 0)
924 		err(2, "unable to limit rights on: %s", file1);
925 
926 	fp[1] = fopen(file2, "r");
927 	if (fp[1] == NULL)
928 		err(2, "Can't open %s", file2);
929 	if (caph_rights_limit(fileno(fp[1]), &rights_ro) < 0)
930 		err(2, "unable to limit rights on: %s", file2);
931 
932 	fp[2] = fopen(file3, "r");
933 	if (fp[2] == NULL)
934 		err(2, "Can't open %s", file3);
935 	if (caph_rights_limit(fileno(fp[2]), &rights_ro) < 0)
936 		err(2, "unable to limit rights on: %s", file3);
937 
938 	if (pipe(fd13))
939 		err(2, "pipe");
940 	if (pipe(fd23))
941 		err(2, "pipe");
942 
943 	diffargv[diffargc] = file1;
944 	diffargv[diffargc + 1] = file3;
945 	diffargv[diffargc + 2] = NULL;
946 
947 	nleft = 0;
948 	pd13 = diffexec(diffprog, diffargv, fd13);
949 	EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
950 	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
951 		err(2, "kevent1");
952 	nleft++;
953 
954 	diffargv[diffargc] = file2;
955 	pd23 = diffexec(diffprog, diffargv, fd23);
956 	EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
957 	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
958 		err(2, "kevent2");
959 	nleft++;
960 
961 	caph_cache_catpages();
962 	if (caph_enter() < 0)
963 		err(2, "unable to enter capability mode");
964 
965 	/* parse diffs */
966 	increase();
967 	m = readin(fd13[0], &d13);
968 	n = readin(fd23[0], &d23);
969 
970 	/* waitpid cooked over pdforks */
971 	while (nleft > 0) {
972 		nke = kevent(kq, NULL, 0, e, nleft, NULL);
973 		if (nke == -1)
974 			err(2, "kevent");
975 		for (i = 0; i < nke; i++) {
976 			status = e[i].data;
977 			if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
978 				errx(2, "diff exited abnormally");
979 			else if (WIFSIGNALED(status))
980 				errx(2, "diff killed by signal %d",
981 				    WTERMSIG(status));
982 		}
983 		nleft -= nke;
984 	}
985 	merge(m, n);
986 
987 	return (EXIT_SUCCESS);
988 }
989