xref: /freebsd-src/usr.bin/diff3/diff3.c (revision e1910ebda4d5972aef64aaf67ea7bcbbba16fa4f)
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 <string.h>
88 #include <unistd.h>
89 
90 
91 /*
92  * "from" is first in range of changed lines; "to" is last+1
93  * from=to=line after point of insertion for added lines.
94  */
95 struct range {
96 	int from;
97 	int to;
98 };
99 
100 struct diff {
101 	struct range old;
102 	struct range new;
103 };
104 
105 static size_t szchanges;
106 
107 static struct diff *d13;
108 static struct diff *d23;
109 /*
110  * "de" is used to gather editing scripts.  These are later spewed out in
111  * reverse order.  Its first element must be all zero, the "new" component
112  * of "de" contains line positions or byte positions depending on when you
113  * look (!?).  Array overlap indicates which sections in "de" correspond to
114  * lines that are different in all three files.
115  */
116 static struct diff *de;
117 static char *overlap;
118 static int  overlapcnt;
119 static FILE *fp[3];
120 static int cline[3];		/* # of the last-read line in each file (0-2) */
121 /*
122  * The latest known correspondence between line numbers of the 3 files
123  * is stored in last[1-3];
124  */
125 static int last[4];
126 static int Aflag, eflag, iflag, mflag, Tflag;
127 static int oflag;		/* indicates whether to mark overlaps (-E or -X)*/
128 static int strip_cr;
129 static char *f1mark, *f2mark, *f3mark;
130 
131 static bool duplicate(struct range *, struct range *);
132 static int edit(struct diff *, bool, int);
133 static char *getchange(FILE *);
134 static char *get_line(FILE *, size_t *);
135 static int number(char **);
136 static int readin(int fd, struct diff **);
137 static int skip(int, int, const char *);
138 static void change(int, struct range *, bool);
139 static void keep(int, struct range *);
140 static void merge(int, int);
141 static void prange(struct range *);
142 static void repos(int);
143 static void edscript(int) __dead2;
144 static void increase(void);
145 static void usage(void) __dead2;
146 
147 enum {
148 	DIFFPROG_OPT,
149 	STRIPCR_OPT,
150 };
151 
152 #define MAX_CHECK 768	/* 3 kb of chars */
153 #define DIFF_PATH "/usr/bin/diff"
154 
155 
156 #define OPTIONS "3aAeEiL:mTxX"
157 static struct option longopts[] = {
158 	{ "ed",			no_argument,		NULL,	'e' },
159 	{ "show-overlap",	no_argument,		NULL,	'E' },
160 	{ "overlap-only",	no_argument,		NULL,	'x' },
161 	{ "initial-tab",	no_argument,		NULL,	'T' },
162 	{ "text",		no_argument,		NULL,	'a' },
163 	{ "strip-trailing-cr",	no_argument,		NULL,	STRIPCR_OPT },
164 	{ "show-all",		no_argument,		NULL,	'A' },
165 	{ "easy-only",		no_argument,		NULL,	'3' },
166 	{ "merge",		no_argument,		NULL,	'm' },
167 	{ "label",		required_argument,	NULL,	'L' },
168 	{ "diff-program",	required_argument,	NULL,	DIFFPROG_OPT },
169 };
170 
171 static void
172 usage(void)
173 {
174 	fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L lable1] [-L label2] "
175 	    "[ -L label3] file1 file2 file3\n");
176 	exit (2);
177 }
178 
179 static int
180 readin(int fd, struct diff **dd)
181 {
182 	int a, b, c, d;
183 	size_t i;
184 	char kind, *p;
185 	FILE *f;
186 
187 	f = fdopen(fd, "r");
188 	if (f == NULL)
189 		err(2, "fdopen");
190 	for (i=0; (p = getchange(f)); i++) {
191 		if (i >= szchanges - 1)
192 			increase();
193 		a = b = number(&p);
194 		if (*p == ',') {
195 			p++;
196 			b = number(&p);
197 		}
198 		kind = *p++;
199 		c = d = number(&p);
200 		if (*p==',') {
201 			p++;
202 			d = number(&p);
203 		}
204 		if (kind == 'a')
205 			a++;
206 		if (kind == 'd')
207 			c++;
208 		b++;
209 		d++;
210 		(*dd)[i].old.from = a;
211 		(*dd)[i].old.to = b;
212 		(*dd)[i].new.from = c;
213 		(*dd)[i].new.to = d;
214 	}
215 	if (i) {
216 		(*dd)[i].old.from = (*dd)[i-1].old.to;
217 		(*dd)[i].new.from = (*dd)[i-1].new.to;
218 	}
219 	fclose(f);
220 	return (i);
221 }
222 
223 static int
224 diffexec(const char *diffprog, char **diffargv, int fd[])
225 {
226 	int pid, pd;
227 
228 	switch (pid = pdfork(&pd, PD_CLOEXEC)) {
229 	case 0:
230 		close(fd[0]);
231 		if (dup2(fd[1], STDOUT_FILENO) == -1)
232 			err(2, "child could not duplicate descriptor");
233 		close(fd[1]);
234 		execvp(diffprog, diffargv);
235 		err(2, "could not execute diff: %s", diffprog);
236 		break;
237 	case -1:
238 		err(2, "could not fork");
239 		break;
240 	}
241 	close(fd[1]);
242 	return (pd);
243 }
244 
245 static int
246 number(char **lc)
247 {
248 	int nn;
249 
250 	nn = 0;
251 	while (isdigit((unsigned char)(**lc)))
252 		nn = nn*10 + *(*lc)++ - '0';
253 	return (nn);
254 }
255 
256 static char *
257 getchange(FILE *b)
258 {
259 	char *line;
260 
261 	while ((line = get_line(b, NULL))) {
262 		if (isdigit((unsigned char)line[0]))
263 			return (line);
264 	}
265 	return (NULL);
266 }
267 
268 
269 static char *
270 get_line(FILE *b, size_t *n)
271 {
272 	char *cp;
273 	size_t len;
274 	static char *buf;
275 	static size_t bufsize;
276 
277 	if ((cp = fgetln(b, &len)) == NULL)
278 		return (NULL);
279 
280 	if (cp[len - 1] != '\n')
281 		len++;
282 	if (len + 1 > bufsize) {
283 		do {
284 			bufsize += 1024;
285 		} while (len + 1 > bufsize);
286 		if ((buf = realloc(buf, bufsize)) == NULL)
287 			err(EXIT_FAILURE, NULL);
288 	}
289 	memcpy(buf, cp, len - 1);
290 	buf[len - 1] = '\n';
291 	buf[len] = '\0';
292 	if (n != NULL)
293 		*n = len;
294 	return (buf);
295 }
296 
297 static void
298 merge(int m1, int m2)
299 {
300 	struct diff *d1, *d2, *d3;
301 	int j, t1, t2;
302 	bool dup = false;
303 
304 	d1 = d13;
305 	d2 = d23;
306 	j = 0;
307 
308 	while ((t1 = d1 < d13 + m1) | (t2 = d2 < d23 + m2)) {
309 		/* first file is different from the others */
310 		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
311 			/* stuff peculiar to 1st file */
312 			if (eflag == 0) {
313 				printf("====1\n");
314 				change(1, &d1->old, false);
315 				keep(2, &d1->new);
316 				change(3, &d1->new, false);
317 			}
318 			d1++;
319 			continue;
320 		}
321 		/* second file is different from others */
322 		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
323 			if (eflag == 0) {
324 				printf("====2\n");
325 				keep(1, &d2->new);
326 				change(3, &d2->new, false);
327 				change(2, &d2->old, false);
328 			}
329 			d2++;
330 			continue;
331 		}
332 		/*
333 		 * Merge overlapping changes in first file
334 		 * this happens after extension (see below).
335 		 */
336 		if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
337 			d1[1].old.from = d1->old.from;
338 			d1[1].new.from = d1->new.from;
339 			d1++;
340 			continue;
341 		}
342 
343 		/* merge overlapping changes in second */
344 		if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
345 			d2[1].old.from = d2->old.from;
346 			d2[1].new.from = d2->new.from;
347 			d2++;
348 			continue;
349 		}
350 		/* stuff peculiar to third file or different in all */
351 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
352 			dup = duplicate(&d1->old, &d2->old);
353 			/*
354 			 * dup = 0 means all files differ
355 			 * dup = 1 means files 1 and 2 identical
356 			 */
357 			if (eflag == 0) {
358 				printf("====%s\n", dup ? "3" : "");
359 				change(1, &d1->old, dup);
360 				change(2, &d2->old, false);
361 				d3 = d1->old.to > d1->old.from ? d1 : d2;
362 				change(3, &d3->new, false);
363 			} else
364 				j = edit(d1, dup, j);
365 			d1++;
366 			d2++;
367 			continue;
368 		}
369 		/*
370 		 * Overlapping changes from file 1 and 2; extend changes
371 		 * appropriately to make them coincide.
372 		 */
373 		if (d1->new.from < d2->new.from) {
374 			d2->old.from -= d2->new.from - d1->new.from;
375 			d2->new.from = d1->new.from;
376 		} else if (d2->new.from < d1->new.from) {
377 			d1->old.from -= d1->new.from - d2->new.from;
378 			d1->new.from = d2->new.from;
379 		}
380 		if (d1->new.to > d2->new.to) {
381 			d2->old.to += d1->new.to - d2->new.to;
382 			d2->new.to = d1->new.to;
383 		} else if (d2->new.to > d1->new.to) {
384 			d1->old.to += d2->new.to - d1->new.to;
385 			d1->new.to = d2->new.to;
386 		}
387 	}
388 	if (eflag)
389 		edscript(j);
390 }
391 
392 /*
393  * The range of lines rold.from thru rold.to in file i is to be changed.
394  * It is to be printed only if it does not duplicate something to be
395  * printed later.
396  */
397 static void
398 change(int i, struct range *rold, bool dup)
399 {
400 
401 	printf("%d:", i);
402 	last[i] = rold->to;
403 	prange(rold);
404 	if (dup)
405 		return;
406 	i--;
407 	skip(i, rold->from, NULL);
408 	skip(i, rold->to, "  ");
409 }
410 
411 /*
412  * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or
413  * n1.
414  */
415 static void
416 prange(struct range *rold)
417 {
418 
419 	if (rold->to <= rold->from)
420 		printf("%da\n", rold->from - 1);
421 	else {
422 		printf("%d", rold->from);
423 		if (rold->to > rold->from+1)
424 			printf(",%d", rold->to - 1);
425 		printf("c\n");
426 	}
427 }
428 
429 /*
430  * No difference was reported by diff between file 1 (or 2) and file 3,
431  * and an artificial dummy difference (trange) must be ginned up to
432  * correspond to the change reported in the other file.
433  */
434 static void
435 keep(int i, struct range *rnew)
436 {
437 	int delta;
438 	struct range trange;
439 
440 	delta = last[3] - last[i];
441 	trange.from = rnew->from - delta;
442 	trange.to = rnew->to - delta;
443 	change(i, &trange, true);
444 }
445 
446 /*
447  * skip to just before line number from in file "i".  If "pr" is non-NULL,
448  * print all skipped stuff with string pr as a prefix.
449  */
450 static int
451 skip(int i, int from, const char *pr)
452 {
453 	size_t j, n;
454 	char *line;
455 
456 	for (n = 0; cline[i] < from - 1; n += j) {
457 		if ((line = get_line(fp[i], &j)) == NULL)
458 			errx(EXIT_FAILURE, "logic error");
459 		if (pr != NULL)
460 			printf("%s%s", Tflag == 1? "\t" : pr, line);
461 		cline[i]++;
462 	}
463 	return ((int) n);
464 }
465 
466 /*
467  * Return 1 or 0 according as the old range (in file 1) contains exactly
468  * the same data as the new range (in file 2).
469  */
470 static bool
471 duplicate(struct range *r1, struct range *r2)
472 {
473 	int c, d;
474 	int nchar;
475 	int nline;
476 
477 	if (r1->to-r1->from != r2->to-r2->from)
478 		return (0);
479 	skip(0, r1->from, NULL);
480 	skip(1, r2->from, NULL);
481 	nchar = 0;
482 	for (nline=0; nline < r1->to - r1->from; nline++) {
483 		do {
484 			c = getc(fp[0]);
485 			d = getc(fp[1]);
486 			if (c == -1 || d== -1)
487 				errx(EXIT_FAILURE, "logic error");
488 			nchar++;
489 			if (c != d) {
490 				repos(nchar);
491 				return (0);
492 			}
493 		} while (c != '\n');
494 	}
495 	repos(nchar);
496 	return (1);
497 }
498 
499 static void
500 repos(int nchar)
501 {
502 	int i;
503 
504 	for (i = 0; i < 2; i++)
505 		(void)fseek(fp[i], (long)-nchar, SEEK_CUR);
506 }
507 /*
508  * collect an editing script for later regurgitation
509  */
510 static int
511 edit(struct diff *diff, bool dup, int j)
512 {
513 
514 	if (((dup + 1) & eflag) == 0)
515 		return (j);
516 	j++;
517 	overlap[j] = !dup;
518 	if (!dup)
519 		overlapcnt++;
520 	de[j].old.from = diff->old.from;
521 	de[j].old.to = diff->old.to;
522 	de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL);
523 	de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL);
524 	return (j);
525 }
526 
527 /* regurgitate */
528 static void
529 edscript(int n)
530 {
531 	int k;
532 	size_t j;
533 	char block[BUFSIZ];
534 
535 	for (; n > 0; n--) {
536 		if (!oflag || !overlap[n]) {
537 			prange(&de[n].old);
538 		} else {
539 			printf("%da\n", de[n].old.to -1);
540 			if (Aflag) {
541 				printf("%s\n", f2mark);
542 				fseek(fp[1], de[n].old.from, SEEK_SET);
543 				for (k = de[n].old.to - de[n].old.from; k > 0; k -= j) {
544 					j = k > BUFSIZ ? BUFSIZ : k;
545 					if (fread(block, 1, j, fp[1]) != j)
546 						errx(2, "logic error");
547 					fwrite(block, 1, j, stdout);
548 				}
549 				printf("\n");
550 			}
551 			printf("=======\n");
552 		}
553 		fseek(fp[2], (long)de[n].new.from, SEEK_SET);
554 		for (k = de[n].new.to - de[n].new.from; k > 0; k-= j) {
555 			j = k > BUFSIZ ? BUFSIZ : k;
556 			if (fread(block, 1, j, fp[2]) != j)
557 				errx(2, "logic error");
558 			fwrite(block, 1, j, stdout);
559 		}
560 		if (!oflag || !overlap[n])
561 			printf(".\n");
562 		else {
563 			printf("%s\n.\n", f3mark);
564 			printf("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
565 		}
566 	}
567 	if (iflag)
568 		printf("w\nq\n");
569 
570 	exit(eflag == 0 ? overlapcnt : 0);
571 }
572 
573 static void
574 increase(void)
575 {
576 	struct diff *p;
577 	char *q;
578 	size_t newsz, incr;
579 
580 	/* are the memset(3) calls needed? */
581 	newsz = szchanges == 0 ? 64 : 2 * szchanges;
582 	incr = newsz - szchanges;
583 
584 	p = realloc(d13, newsz * sizeof(struct diff));
585 	if (p == NULL)
586 		err(1, NULL);
587 	memset(p + szchanges, 0, incr * sizeof(struct diff));
588 	d13 = p;
589 	p = realloc(d23, newsz * sizeof(struct diff));
590 	if (p == NULL)
591 		err(1, NULL);
592 	memset(p + szchanges, 0, incr * sizeof(struct diff));
593 	d23 = p;
594 	p = realloc(de, newsz * sizeof(struct diff));
595 	if (p == NULL)
596 		err(1, NULL);
597 	memset(p + szchanges, 0, incr * sizeof(struct diff));
598 	de = p;
599 	q = realloc(overlap, newsz * sizeof(char));
600 	if (q == NULL)
601 		err(1, NULL);
602 	memset(q + szchanges, 0, incr * sizeof(char));
603 	overlap = q;
604 	szchanges = newsz;
605 }
606 
607 
608 int
609 main(int argc, char **argv)
610 {
611 	int ch, nblabels, status, m, n, kq, nke, nleft, i;
612 	char *labels[] = { NULL, NULL, NULL };
613 	const char *diffprog = DIFF_PATH;
614 	char *file1, *file2, *file3;
615 	char *diffargv[6];
616 	int diffargc = 0;
617 	int fd13[2], fd23[2];
618 	int pd13, pd23;
619 	cap_rights_t rights_ro;
620 	struct kevent *e;
621 
622 	nblabels = 0;
623 	eflag = 0;
624 	oflag = 0;
625 	diffargv[diffargc++] = __DECONST(char *, diffprog);
626 	while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
627 		switch (ch) {
628 		case '3':
629 			eflag = 2;
630 			break;
631 		case 'a':
632 			diffargv[diffargc++] = __DECONST(char *, "-a");
633 			break;
634 		case 'A':
635 			Aflag = 1;
636 			break;
637 		case 'e':
638 			eflag = 3;
639 			break;
640 		case 'E':
641 			eflag = 3;
642 			oflag = 1;
643 			break;
644 		case 'i':
645 			iflag = 1;
646 			break;
647 		case 'L':
648 			oflag = 1;
649 			if (nblabels >= 3)
650 				errx(2, "too many file label options");
651 			labels[nblabels++] = optarg;
652 			break;
653 		case 'm':
654 			Aflag = 1;
655 			oflag = 1;
656 			mflag = 1;
657 			break;
658 		case 'T':
659 			Tflag = 1;
660 			break;
661 		case 'x':
662 			eflag = 1;
663 			break;
664 		case 'X':
665 			oflag = 1;
666 			eflag = 1;
667 			break;
668 		case DIFFPROG_OPT:
669 			diffprog = optarg;
670 			break;
671 		case STRIPCR_OPT:
672 			strip_cr = 1;
673 			break;
674 		}
675 	}
676 	argc -= optind;
677 	argv += optind;
678 
679 	if (Aflag) {
680 		eflag = 3;
681 		oflag = 1;
682 	}
683 
684 	if (argc != 3)
685 		usage();
686 
687 	if (caph_limit_stdio() == -1)
688 		err(2, "unable to limit stdio");
689 
690 	cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
691 
692 	kq = kqueue();
693 	if (kq == -1)
694 		err(2, "kqueue");
695 
696 	e = malloc(2 * sizeof(struct kevent));
697 	if (e == NULL)
698 		err(2, "malloc");
699 
700 	/* TODO stdio */
701 	file1 = argv[0];
702 	file2 = argv[1];
703 	file3 = argv[2];
704 
705 	if (oflag) {
706 		asprintf(&f1mark, "<<<<<<< %s",
707 		    labels[0] != NULL ? labels[0] : file1);
708 		if (f1mark == NULL)
709 			err(2, "asprintf");
710 		asprintf(&f2mark, "||||||| %s",
711 		    labels[1] != NULL ? labels[1] : file2);
712 		if (f2mark == NULL)
713 			err(2, "asprintf");
714 		asprintf(&f3mark, ">>>>>>> %s",
715 		    labels[2] != NULL ? labels[2] : file3);
716 		if (f3mark == NULL)
717 			err(2, "asprintf");
718 	}
719 	fp[0] = fopen(file1, "r");
720 	if (fp[0] == NULL)
721 		err(2, "Can't open %s", file1);
722 	if (cap_rights_limit(fileno(fp[0]), &rights_ro) < 0)
723 		err(2, "unable to limit rights on: %s", file1);
724 
725 	fp[1] = fopen(file2, "r");
726 	if (fp[1] == NULL)
727 		err(2, "Can't open %s", file2);
728 	if (cap_rights_limit(fileno(fp[1]), &rights_ro) < 0)
729 		err(2, "unable to limit rights on: %s", file2);
730 
731 	fp[2] = fopen(file3, "r");
732 	if (fp[2] == NULL)
733 		err(2, "Can't open %s", file3);
734 	if (cap_rights_limit(fileno(fp[2]), &rights_ro) < 0)
735 		err(2, "unable to limit rights on: %s", file3);
736 
737 	if (pipe(fd13))
738 		err(2, "pipe");
739 	if (pipe(fd23))
740 		err(2, "pipe");
741 
742 	diffargv[diffargc] = file1;
743 	diffargv[diffargc + 1] = file3;
744 	diffargv[diffargc + 2] = NULL;
745 
746 	nleft = 0;
747 	pd13 = diffexec(diffprog, diffargv, fd13);
748 	EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
749 	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
750 		err(2, "kevent1");
751 	nleft++;
752 
753 	diffargv[diffargc] = file2;
754 	pd23 = diffexec(diffprog, diffargv, fd23);
755 	EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
756 	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
757 		err(2, "kevent2");
758 	nleft++;
759 
760 	caph_cache_catpages();
761 	if (cap_enter() < 0 && errno != ENOSYS)
762 		err(2, "unable to enter capability mode");
763 
764 	/* parse diffs */
765 	increase();
766 	m = readin(fd13[0], &d13);
767 	n = readin(fd23[0], &d23);
768 
769 	/* waitpid cooked over pdforks */
770 	while (nleft > 0) {
771 		nke = kevent(kq, NULL, 0, e, nleft, NULL);
772 		if (nke == -1)
773 			err(2, "kevent");
774 		for (i = 0; i < nke; i++) {
775 			status = e[i].data;
776 			if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
777 				errx(2, "diff exited abormally");
778 			else if (WIFSIGNALED(status))
779 				errx(2, "diff killed by signal %d",
780 				    WTERMSIG(status));
781 		}
782 		nleft -= nke;
783 	}
784 	merge(m, n);
785 
786 	return (EXIT_SUCCESS);
787 }
788