xref: /freebsd/usr.bin/diff3/diff3.c (revision 53f151f90603580d0c0a8fa1840ba1262958a7c1)
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  	struct range old;
104  	struct range new;
105  };
106  
107  static size_t szchanges;
108  
109  static struct diff *d13;
110  static struct diff *d23;
111  /*
112   * "de" is used to gather editing scripts.  These are later spewed out in
113   * reverse order.  Its first element must be all zero, the "new" component
114   * of "de" contains line positions or byte positions depending on when you
115   * look (!?).  Array overlap indicates which sections in "de" correspond to
116   * lines that are different in all three files.
117   */
118  static struct diff *de;
119  static char *overlap;
120  static int  overlapcnt;
121  static FILE *fp[3];
122  static int cline[3];		/* # of the last-read line in each file (0-2) */
123  /*
124   * The latest known correspondence between line numbers of the 3 files
125   * is stored in last[1-3];
126   */
127  static int last[4];
128  static int Aflag, eflag, iflag, mflag, Tflag;
129  static int oflag;		/* indicates whether to mark overlaps (-E or -X)*/
130  static int strip_cr;
131  static char *f1mark, *f2mark, *f3mark;
132  
133  static bool duplicate(struct range *, struct range *);
134  static int edit(struct diff *, bool, int);
135  static char *getchange(FILE *);
136  static char *get_line(FILE *, size_t *);
137  static int readin(int fd, struct diff **);
138  static int skip(int, int, const char *);
139  static void change(int, struct range *, bool);
140  static void keep(int, struct range *);
141  static void merge(int, int);
142  static void prange(struct range *);
143  static void repos(int);
144  static void edscript(int) __dead2;
145  static void increase(void);
146  static void usage(void) __dead2;
147  
148  enum {
149  	DIFFPROG_OPT,
150  	STRIPCR_OPT,
151  };
152  
153  #define DIFF_PATH "/usr/bin/diff"
154  
155  #define OPTIONS "3aAeEiL:mTxX"
156  static struct option longopts[] = {
157  	{ "ed",			no_argument,		NULL,	'e' },
158  	{ "show-overlap",	no_argument,		NULL,	'E' },
159  	{ "overlap-only",	no_argument,		NULL,	'x' },
160  	{ "initial-tab",	no_argument,		NULL,	'T' },
161  	{ "text",		no_argument,		NULL,	'a' },
162  	{ "strip-trailing-cr",	no_argument,		NULL,	STRIPCR_OPT },
163  	{ "show-all",		no_argument,		NULL,	'A' },
164  	{ "easy-only",		no_argument,		NULL,	'3' },
165  	{ "merge",		no_argument,		NULL,	'm' },
166  	{ "label",		required_argument,	NULL,	'L' },
167  	{ "diff-program",	required_argument,	NULL,	DIFFPROG_OPT },
168  };
169  
170  static void
171  usage(void)
172  {
173  	fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L lable1] [-L label2] "
174  	    "[ -L label3] file1 file2 file3\n");
175  	exit (2);
176  }
177  
178  static int
179  readin(int fd, struct diff **dd)
180  {
181  	int a, b, c, d;
182  	size_t i;
183  	char kind, *p;
184  	FILE *f;
185  
186  	f = fdopen(fd, "r");
187  	if (f == NULL)
188  		err(2, "fdopen");
189  	for (i=0; (p = getchange(f)); i++) {
190  		if (i >= szchanges - 1)
191  			increase();
192  		a = b = (int)strtoimax(p, &p, 10);
193  		if (*p == ',') {
194  			p++;
195  			b = (int)strtoimax(p, &p, 10);
196  		}
197  		kind = *p++;
198  		c = d = (int)strtoimax(p, &p, 10);
199  		if (*p==',') {
200  			p++;
201  			d = (int)strtoimax(p, &p, 10);
202  		}
203  		if (kind == 'a')
204  			a++;
205  		if (kind == 'd')
206  			c++;
207  		b++;
208  		d++;
209  		(*dd)[i].old.from = a;
210  		(*dd)[i].old.to = b;
211  		(*dd)[i].new.from = c;
212  		(*dd)[i].new.to = d;
213  	}
214  	if (i) {
215  		(*dd)[i].old.from = (*dd)[i-1].old.to;
216  		(*dd)[i].new.from = (*dd)[i-1].new.to;
217  	}
218  	fclose(f);
219  	return (i);
220  }
221  
222  static int
223  diffexec(const char *diffprog, char **diffargv, int fd[])
224  {
225  	int pid, pd;
226  
227  	switch (pid = pdfork(&pd, PD_CLOEXEC)) {
228  	case 0:
229  		close(fd[0]);
230  		if (dup2(fd[1], STDOUT_FILENO) == -1)
231  			err(2, "child could not duplicate descriptor");
232  		close(fd[1]);
233  		execvp(diffprog, diffargv);
234  		err(2, "could not execute diff: %s", diffprog);
235  		break;
236  	case -1:
237  		err(2, "could not fork");
238  		break;
239  	}
240  	close(fd[1]);
241  	return (pd);
242  }
243  
244  static char *
245  getchange(FILE *b)
246  {
247  	char *line;
248  
249  	while ((line = get_line(b, NULL))) {
250  		if (isdigit((unsigned char)line[0]))
251  			return (line);
252  	}
253  	return (NULL);
254  }
255  
256  
257  static char *
258  get_line(FILE *b, size_t *n)
259  {
260  	ssize_t len;
261  	static char *buf = NULL;
262  	static size_t bufsize = 0;
263  
264  	if ((len = getline(&buf, &bufsize, b)) < 0)
265  		return (NULL);
266  
267  	if (n != NULL)
268  		*n = len;
269  
270  	return (buf);
271  }
272  
273  static void
274  merge(int m1, int m2)
275  {
276  	struct diff *d1, *d2, *d3;
277  	int j, t1, t2;
278  	bool dup = false;
279  
280  	d1 = d13;
281  	d2 = d23;
282  	j = 0;
283  
284  	while ((t1 = d1 < d13 + m1) | (t2 = d2 < d23 + m2)) {
285  		/* first file is different from the others */
286  		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
287  			/* stuff peculiar to 1st file */
288  			if (eflag == 0) {
289  				printf("====1\n");
290  				change(1, &d1->old, false);
291  				keep(2, &d1->new);
292  				change(3, &d1->new, false);
293  			}
294  			d1++;
295  			continue;
296  		}
297  		/* second file is different from others */
298  		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
299  			if (eflag == 0) {
300  				printf("====2\n");
301  				keep(1, &d2->new);
302  				change(3, &d2->new, false);
303  				change(2, &d2->old, false);
304  			}
305  			d2++;
306  			continue;
307  		}
308  		/*
309  		 * Merge overlapping changes in first file
310  		 * this happens after extension (see below).
311  		 */
312  		if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
313  			d1[1].old.from = d1->old.from;
314  			d1[1].new.from = d1->new.from;
315  			d1++;
316  			continue;
317  		}
318  
319  		/* merge overlapping changes in second */
320  		if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
321  			d2[1].old.from = d2->old.from;
322  			d2[1].new.from = d2->new.from;
323  			d2++;
324  			continue;
325  		}
326  		/* stuff peculiar to third file or different in all */
327  		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
328  			dup = duplicate(&d1->old, &d2->old);
329  			/*
330  			 * dup = 0 means all files differ
331  			 * dup = 1 means files 1 and 2 identical
332  			 */
333  			if (eflag == 0) {
334  				printf("====%s\n", dup ? "3" : "");
335  				change(1, &d1->old, dup);
336  				change(2, &d2->old, false);
337  				d3 = d1->old.to > d1->old.from ? d1 : d2;
338  				change(3, &d3->new, false);
339  			} else
340  				j = edit(d1, dup, j);
341  			d1++;
342  			d2++;
343  			continue;
344  		}
345  		/*
346  		 * Overlapping changes from file 1 and 2; extend changes
347  		 * appropriately to make them coincide.
348  		 */
349  		if (d1->new.from < d2->new.from) {
350  			d2->old.from -= d2->new.from - d1->new.from;
351  			d2->new.from = d1->new.from;
352  		} else if (d2->new.from < d1->new.from) {
353  			d1->old.from -= d1->new.from - d2->new.from;
354  			d1->new.from = d2->new.from;
355  		}
356  		if (d1->new.to > d2->new.to) {
357  			d2->old.to += d1->new.to - d2->new.to;
358  			d2->new.to = d1->new.to;
359  		} else if (d2->new.to > d1->new.to) {
360  			d1->old.to += d2->new.to - d1->new.to;
361  			d1->new.to = d2->new.to;
362  		}
363  	}
364  	if (eflag)
365  		edscript(j);
366  }
367  
368  /*
369   * The range of lines rold.from thru rold.to in file i is to be changed.
370   * It is to be printed only if it does not duplicate something to be
371   * printed later.
372   */
373  static void
374  change(int i, struct range *rold, bool dup)
375  {
376  
377  	printf("%d:", i);
378  	last[i] = rold->to;
379  	prange(rold);
380  	if (dup)
381  		return;
382  	i--;
383  	skip(i, rold->from, NULL);
384  	skip(i, rold->to, "  ");
385  }
386  
387  /*
388   * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or
389   * n1.
390   */
391  static void
392  prange(struct range *rold)
393  {
394  
395  	if (rold->to <= rold->from)
396  		printf("%da\n", rold->from - 1);
397  	else {
398  		printf("%d", rold->from);
399  		if (rold->to > rold->from+1)
400  			printf(",%d", rold->to - 1);
401  		printf("c\n");
402  	}
403  }
404  
405  /*
406   * No difference was reported by diff between file 1 (or 2) and file 3,
407   * and an artificial dummy difference (trange) must be ginned up to
408   * correspond to the change reported in the other file.
409   */
410  static void
411  keep(int i, struct range *rnew)
412  {
413  	int delta;
414  	struct range trange;
415  
416  	delta = last[3] - last[i];
417  	trange.from = rnew->from - delta;
418  	trange.to = rnew->to - delta;
419  	change(i, &trange, true);
420  }
421  
422  /*
423   * skip to just before line number from in file "i".  If "pr" is non-NULL,
424   * print all skipped stuff with string pr as a prefix.
425   */
426  static int
427  skip(int i, int from, const char *pr)
428  {
429  	size_t j, n;
430  	char *line;
431  
432  	for (n = 0; cline[i] < from - 1; n += j) {
433  		if ((line = get_line(fp[i], &j)) == NULL)
434  			errx(EXIT_FAILURE, "logic error");
435  		if (pr != NULL)
436  			printf("%s%s", Tflag == 1? "\t" : pr, line);
437  		cline[i]++;
438  	}
439  	return ((int) n);
440  }
441  
442  /*
443   * Return 1 or 0 according as the old range (in file 1) contains exactly
444   * the same data as the new range (in file 2).
445   */
446  static bool
447  duplicate(struct range *r1, struct range *r2)
448  {
449  	int c, d;
450  	int nchar;
451  	int nline;
452  
453  	if (r1->to-r1->from != r2->to-r2->from)
454  		return (0);
455  	skip(0, r1->from, NULL);
456  	skip(1, r2->from, NULL);
457  	nchar = 0;
458  	for (nline=0; nline < r1->to - r1->from; nline++) {
459  		do {
460  			c = getc(fp[0]);
461  			d = getc(fp[1]);
462  			if (c == -1 || d== -1)
463  				errx(EXIT_FAILURE, "logic error");
464  			nchar++;
465  			if (c != d) {
466  				repos(nchar);
467  				return (0);
468  			}
469  		} while (c != '\n');
470  	}
471  	repos(nchar);
472  	return (1);
473  }
474  
475  static void
476  repos(int nchar)
477  {
478  	int i;
479  
480  	for (i = 0; i < 2; i++)
481  		(void)fseek(fp[i], (long)-nchar, SEEK_CUR);
482  }
483  /*
484   * collect an editing script for later regurgitation
485   */
486  static int
487  edit(struct diff *diff, bool dup, int j)
488  {
489  
490  	if (((dup + 1) & eflag) == 0)
491  		return (j);
492  	j++;
493  	overlap[j] = !dup;
494  	if (!dup)
495  		overlapcnt++;
496  	de[j].old.from = diff->old.from;
497  	de[j].old.to = diff->old.to;
498  	de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL);
499  	de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL);
500  	return (j);
501  }
502  
503  /* regurgitate */
504  static void
505  edscript(int n)
506  {
507  	int k;
508  	size_t j;
509  	char block[BUFSIZ];
510  
511  	for (; n > 0; n--) {
512  		if (!oflag || !overlap[n]) {
513  			prange(&de[n].old);
514  		} else {
515  			printf("%da\n", de[n].old.to -1);
516  			if (Aflag) {
517  				printf("%s\n", f2mark);
518  				fseek(fp[1], de[n].old.from, SEEK_SET);
519  				for (k = de[n].old.to - de[n].old.from; k > 0; k -= j) {
520  					j = k > BUFSIZ ? BUFSIZ : k;
521  					if (fread(block, 1, j, fp[1]) != j)
522  						errx(2, "logic error");
523  					fwrite(block, 1, j, stdout);
524  				}
525  				printf("\n");
526  			}
527  			printf("=======\n");
528  		}
529  		fseek(fp[2], (long)de[n].new.from, SEEK_SET);
530  		for (k = de[n].new.to - de[n].new.from; k > 0; k-= j) {
531  			j = k > BUFSIZ ? BUFSIZ : k;
532  			if (fread(block, 1, j, fp[2]) != j)
533  				errx(2, "logic error");
534  			fwrite(block, 1, j, stdout);
535  		}
536  		if (!oflag || !overlap[n])
537  			printf(".\n");
538  		else {
539  			printf("%s\n.\n", f3mark);
540  			printf("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
541  		}
542  	}
543  	if (iflag)
544  		printf("w\nq\n");
545  
546  	exit(eflag == 0 ? overlapcnt : 0);
547  }
548  
549  static void
550  increase(void)
551  {
552  	struct diff *p;
553  	char *q;
554  	size_t newsz, incr;
555  
556  	/* are the memset(3) calls needed? */
557  	newsz = szchanges == 0 ? 64 : 2 * szchanges;
558  	incr = newsz - szchanges;
559  
560  	p = realloc(d13, newsz * sizeof(struct diff));
561  	if (p == NULL)
562  		err(1, NULL);
563  	memset(p + szchanges, 0, incr * sizeof(struct diff));
564  	d13 = p;
565  	p = realloc(d23, newsz * sizeof(struct diff));
566  	if (p == NULL)
567  		err(1, NULL);
568  	memset(p + szchanges, 0, incr * sizeof(struct diff));
569  	d23 = p;
570  	p = realloc(de, newsz * sizeof(struct diff));
571  	if (p == NULL)
572  		err(1, NULL);
573  	memset(p + szchanges, 0, incr * sizeof(struct diff));
574  	de = p;
575  	q = realloc(overlap, newsz * sizeof(char));
576  	if (q == NULL)
577  		err(1, NULL);
578  	memset(q + szchanges, 0, incr * sizeof(char));
579  	overlap = q;
580  	szchanges = newsz;
581  }
582  
583  
584  int
585  main(int argc, char **argv)
586  {
587  	int ch, nblabels, status, m, n, kq, nke, nleft, i;
588  	char *labels[] = { NULL, NULL, NULL };
589  	const char *diffprog = DIFF_PATH;
590  	char *file1, *file2, *file3;
591  	char *diffargv[6];
592  	int diffargc = 0;
593  	int fd13[2], fd23[2];
594  	int pd13, pd23;
595  	cap_rights_t rights_ro;
596  	struct kevent *e;
597  
598  	nblabels = 0;
599  	eflag = 0;
600  	oflag = 0;
601  	diffargv[diffargc++] = __DECONST(char *, diffprog);
602  	while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
603  		switch (ch) {
604  		case '3':
605  			eflag = 2;
606  			break;
607  		case 'a':
608  			diffargv[diffargc++] = __DECONST(char *, "-a");
609  			break;
610  		case 'A':
611  			Aflag = 1;
612  			break;
613  		case 'e':
614  			eflag = 3;
615  			break;
616  		case 'E':
617  			eflag = 3;
618  			oflag = 1;
619  			break;
620  		case 'i':
621  			iflag = 1;
622  			break;
623  		case 'L':
624  			oflag = 1;
625  			if (nblabels >= 3)
626  				errx(2, "too many file label options");
627  			labels[nblabels++] = optarg;
628  			break;
629  		case 'm':
630  			Aflag = 1;
631  			oflag = 1;
632  			mflag = 1;
633  			break;
634  		case 'T':
635  			Tflag = 1;
636  			break;
637  		case 'x':
638  			eflag = 1;
639  			break;
640  		case 'X':
641  			oflag = 1;
642  			eflag = 1;
643  			break;
644  		case DIFFPROG_OPT:
645  			diffprog = optarg;
646  			break;
647  		case STRIPCR_OPT:
648  			strip_cr = 1;
649  			break;
650  		}
651  	}
652  	argc -= optind;
653  	argv += optind;
654  
655  	if (Aflag) {
656  		eflag = 3;
657  		oflag = 1;
658  	}
659  
660  	if (argc != 3)
661  		usage();
662  
663  	if (caph_limit_stdio() == -1)
664  		err(2, "unable to limit stdio");
665  
666  	cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
667  
668  	kq = kqueue();
669  	if (kq == -1)
670  		err(2, "kqueue");
671  
672  	e = malloc(2 * sizeof(struct kevent));
673  	if (e == NULL)
674  		err(2, "malloc");
675  
676  	/* TODO stdio */
677  	file1 = argv[0];
678  	file2 = argv[1];
679  	file3 = argv[2];
680  
681  	if (oflag) {
682  		asprintf(&f1mark, "<<<<<<< %s",
683  		    labels[0] != NULL ? labels[0] : file1);
684  		if (f1mark == NULL)
685  			err(2, "asprintf");
686  		asprintf(&f2mark, "||||||| %s",
687  		    labels[1] != NULL ? labels[1] : file2);
688  		if (f2mark == NULL)
689  			err(2, "asprintf");
690  		asprintf(&f3mark, ">>>>>>> %s",
691  		    labels[2] != NULL ? labels[2] : file3);
692  		if (f3mark == NULL)
693  			err(2, "asprintf");
694  	}
695  	fp[0] = fopen(file1, "r");
696  	if (fp[0] == NULL)
697  		err(2, "Can't open %s", file1);
698  	if (caph_rights_limit(fileno(fp[0]), &rights_ro) < 0)
699  		err(2, "unable to limit rights on: %s", file1);
700  
701  	fp[1] = fopen(file2, "r");
702  	if (fp[1] == NULL)
703  		err(2, "Can't open %s", file2);
704  	if (caph_rights_limit(fileno(fp[1]), &rights_ro) < 0)
705  		err(2, "unable to limit rights on: %s", file2);
706  
707  	fp[2] = fopen(file3, "r");
708  	if (fp[2] == NULL)
709  		err(2, "Can't open %s", file3);
710  	if (caph_rights_limit(fileno(fp[2]), &rights_ro) < 0)
711  		err(2, "unable to limit rights on: %s", file3);
712  
713  	if (pipe(fd13))
714  		err(2, "pipe");
715  	if (pipe(fd23))
716  		err(2, "pipe");
717  
718  	diffargv[diffargc] = file1;
719  	diffargv[diffargc + 1] = file3;
720  	diffargv[diffargc + 2] = NULL;
721  
722  	nleft = 0;
723  	pd13 = diffexec(diffprog, diffargv, fd13);
724  	EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
725  	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
726  		err(2, "kevent1");
727  	nleft++;
728  
729  	diffargv[diffargc] = file2;
730  	pd23 = diffexec(diffprog, diffargv, fd23);
731  	EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
732  	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
733  		err(2, "kevent2");
734  	nleft++;
735  
736  	caph_cache_catpages();
737  	if (caph_enter() < 0)
738  		err(2, "unable to enter capability mode");
739  
740  	/* parse diffs */
741  	increase();
742  	m = readin(fd13[0], &d13);
743  	n = readin(fd23[0], &d23);
744  
745  	/* waitpid cooked over pdforks */
746  	while (nleft > 0) {
747  		nke = kevent(kq, NULL, 0, e, nleft, NULL);
748  		if (nke == -1)
749  			err(2, "kevent");
750  		for (i = 0; i < nke; i++) {
751  			status = e[i].data;
752  			if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
753  				errx(2, "diff exited abormally");
754  			else if (WIFSIGNALED(status))
755  				errx(2, "diff killed by signal %d",
756  				    WTERMSIG(status));
757  		}
758  		nleft -= nke;
759  	}
760  	merge(m, n);
761  
762  	return (EXIT_SUCCESS);
763  }
764