xref: /freebsd/usr.bin/diff3/diff3.c (revision 0bf688786f7d5508b43b50c62f50f022e33b1352)
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  #define EFLAG_NONE 	0
116  #define EFLAG_OVERLAP 	1
117  #define EFLAG_NOOVERLAP	2
118  #define EFLAG_UNMERGED	3
119  
120  static size_t szchanges;
121  
122  static struct diff *d13;
123  static struct diff *d23;
124  /*
125   * "de" is used to gather editing scripts.  These are later spewed out in
126   * reverse order.  Its first element must be all zero, the "old" and "new"
127   * components of "de" contain line positions. Array overlap indicates which
128   * sections in "de" correspond to lines that are different in all three files.
129   */
130  static struct diff *de;
131  static char *overlap;
132  static int  overlapcnt;
133  static FILE *fp[3];
134  static int cline[3];		/* # of the last-read line in each file (0-2) */
135  /*
136   * The latest known correspondence between line numbers of the 3 files
137   * is stored in last[1-3];
138   */
139  static int last[4];
140  static int Aflag, eflag, iflag, mflag, Tflag;
141  static int oflag;		/* indicates whether to mark overlaps (-E or -X) */
142  static int strip_cr;
143  static char *f1mark, *f2mark, *f3mark;
144  static const char *oldmark = "<<<<<<<";
145  static const char *orgmark = "|||||||";
146  static const char *newmark = ">>>>>>>";
147  static const char *divider = "=======";
148  
149  static bool duplicate(struct range *, struct range *);
150  static int edit(struct diff *, bool, int, int);
151  static char *getchange(FILE *);
152  static char *get_line(FILE *, size_t *);
153  static int readin(int fd, struct diff **);
154  static int skip(int, int, const char *);
155  static void change(int, struct range *, bool);
156  static void keep(int, struct range *);
157  static void merge(int, int);
158  static void prange(struct range *, bool);
159  static void repos(int);
160  static void edscript(int) __dead2;
161  static void Ascript(int) __dead2;
162  static void mergescript(int) __dead2;
163  static void increase(void);
164  static void usage(void);
165  static void printrange(FILE *, struct range *);
166  
167  static const char diff3_version[] = "FreeBSD diff3 20220517";
168  
169  enum {
170  	DIFFPROG_OPT,
171  	STRIPCR_OPT,
172  	HELP_OPT,
173  	VERSION_OPT
174  };
175  
176  #define DIFF_PATH "/usr/bin/diff"
177  
178  #define OPTIONS "3aAeEiL:mTxX"
179  static struct option longopts[] = {
180  	{ "ed",			no_argument,		NULL,	'e' },
181  	{ "show-overlap",	no_argument,		NULL,	'E' },
182  	{ "overlap-only",	no_argument,		NULL,	'x' },
183  	{ "initial-tab",	no_argument,		NULL,	'T' },
184  	{ "text",		no_argument,		NULL,	'a' },
185  	{ "strip-trailing-cr",	no_argument,		NULL,	STRIPCR_OPT },
186  	{ "show-all",		no_argument,		NULL,	'A' },
187  	{ "easy-only",		no_argument,		NULL,	'3' },
188  	{ "merge",		no_argument,		NULL,	'm' },
189  	{ "label",		required_argument,	NULL,	'L' },
190  	{ "diff-program",	required_argument,	NULL,	DIFFPROG_OPT },
191  	{ "help",		no_argument,		NULL,	HELP_OPT},
192  	{ "version",		no_argument,		NULL,	VERSION_OPT}
193  };
194  
195  static void
196  usage(void)
197  {
198  	fprintf(stderr, "usage: diff3 [-3aAeEimTxX] [-L label1] [-L label2] "
199  	    "[-L label3] file1 file2 file3\n");
200  }
201  
202  static int
203  readin(int fd, struct diff **dd)
204  {
205  	int a, b, c, d;
206  	size_t i;
207  	char kind, *p;
208  	FILE *f;
209  
210  	f = fdopen(fd, "r");
211  	if (f == NULL)
212  		err(2, "fdopen");
213  	for (i = 0; (p = getchange(f)); i++) {
214  #if DEBUG
215  		(*dd)[i].line = strdup(p);
216  #endif	/* DEBUG */
217  
218  		if (i >= szchanges - 1)
219  			increase();
220  		a = b = (int)strtoimax(p, &p, 10);
221  		if (*p == ',') {
222  			p++;
223  			b = (int)strtoimax(p, &p, 10);
224  		}
225  		kind = *p++;
226  		c = d = (int)strtoimax(p, &p, 10);
227  		if (*p == ',') {
228  			p++;
229  			d = (int)strtoimax(p, &p, 10);
230  		}
231  		if (kind == 'a')
232  			a++;
233  		if (kind == 'd')
234  			c++;
235  		b++;
236  		d++;
237  		(*dd)[i].old.from = a;
238  		(*dd)[i].old.to = b;
239  		(*dd)[i].new.from = c;
240  		(*dd)[i].new.to = d;
241  	}
242  	if (i) {
243  		(*dd)[i].old.from = (*dd)[i - 1].old.to;
244  		(*dd)[i].new.from = (*dd)[i - 1].new.to;
245  	}
246  	fclose(f);
247  	return (i);
248  }
249  
250  static int
251  diffexec(const char *diffprog, char **diffargv, int fd[])
252  {
253  	int pd;
254  
255  	switch (pdfork(&pd, PD_CLOEXEC)) {
256  	case 0:
257  		close(fd[0]);
258  		if (dup2(fd[1], STDOUT_FILENO) == -1)
259  			err(2, "child could not duplicate descriptor");
260  		close(fd[1]);
261  		execvp(diffprog, diffargv);
262  		err(2, "could not execute diff: %s", diffprog);
263  		break;
264  	case -1:
265  		err(2, "could not fork");
266  		break;
267  	}
268  	close(fd[1]);
269  	return (pd);
270  }
271  
272  static char *
273  getchange(FILE *b)
274  {
275  	char *line;
276  
277  	while ((line = get_line(b, NULL))) {
278  		if (isdigit((unsigned char)line[0]))
279  			return (line);
280  	}
281  	return (NULL);
282  }
283  
284  
285  static char *
286  get_line(FILE *b, size_t *n)
287  {
288  	ssize_t len;
289  	static char *buf = NULL;
290  	static size_t bufsize = 0;
291  
292  	if ((len = getline(&buf, &bufsize, b)) < 0)
293  		return (NULL);
294  
295  	if (strip_cr && len >= 2 && strcmp("\r\n", &(buf[len - 2])) == 0) {
296  		buf[len - 2] = '\n';
297  		buf[len - 1] = '\0';
298  		len--;
299  	}
300  
301  	if (n != NULL)
302  		*n = len;
303  
304  	return (buf);
305  }
306  
307  static void
308  merge(int m1, int m2)
309  {
310  	struct diff *d1, *d2, *d3;
311  	int j, t1, t2;
312  	bool dup = false;
313  
314  	d1 = d13;
315  	d2 = d23;
316  	j = 0;
317  
318  	while (t1 = d1 < d13 + m1, t2 = d2 < d23 + m2, t1 || t2) {
319  		/* first file is different from the others */
320  		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
321  			/* stuff peculiar to 1st file */
322  			if (eflag == EFLAG_NONE) {
323  				printf("====1\n");
324  				change(1, &d1->old, false);
325  				keep(2, &d1->new);
326  				change(3, &d1->new, false);
327  			}
328  			d1++;
329  			continue;
330  		}
331  		/* second file is different from others */
332  		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
333  			if (eflag == EFLAG_NONE) {
334  				printf("====2\n");
335  				keep(1, &d2->new);
336  				change(3, &d2->new, false);
337  				change(2, &d2->old, false);
338  			} else if (Aflag || mflag) {
339  				// XXX-THJ: What does it mean for the second file to differ?
340  				j = edit(d2, dup, j, DIFF_TYPE2);
341  			}
342  			d2++;
343  			continue;
344  		}
345  		/*
346  		 * Merge overlapping changes in first file
347  		 * this happens after extension (see below).
348  		 */
349  		if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
350  			d1[1].old.from = d1->old.from;
351  			d1[1].new.from = d1->new.from;
352  			d1++;
353  			continue;
354  		}
355  
356  		/* merge overlapping changes in second */
357  		if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
358  			d2[1].old.from = d2->old.from;
359  			d2[1].new.from = d2->new.from;
360  			d2++;
361  			continue;
362  		}
363  		/* stuff peculiar to third file or different in all */
364  		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
365  			dup = duplicate(&d1->old, &d2->old);
366  			/*
367  			 * dup = 0 means all files differ
368  			 * dup = 1 means files 1 and 2 identical
369  			 */
370  			if (eflag == EFLAG_NONE) {
371  				printf("====%s\n", dup ? "3" : "");
372  				change(1, &d1->old, dup);
373  				change(2, &d2->old, false);
374  				d3 = d1->old.to > d1->old.from ? d1 : d2;
375  				change(3, &d3->new, false);
376  			} else {
377  				j = edit(d1, dup, j, DIFF_TYPE3);
378  			}
379  			dup = false;
380  			d1++;
381  			d2++;
382  			continue;
383  		}
384  		/*
385  		 * Overlapping changes from file 1 and 2; extend changes
386  		 * appropriately to make them coincide.
387  		 */
388  		if (d1->new.from < d2->new.from) {
389  			d2->old.from -= d2->new.from - d1->new.from;
390  			d2->new.from = d1->new.from;
391  		} else if (d2->new.from < d1->new.from) {
392  			d1->old.from -= d1->new.from - d2->new.from;
393  			d1->new.from = d2->new.from;
394  		}
395  		if (d1->new.to > d2->new.to) {
396  			d2->old.to += d1->new.to - d2->new.to;
397  			d2->new.to = d1->new.to;
398  		} else if (d2->new.to > d1->new.to) {
399  			d1->old.to += d2->new.to - d1->new.to;
400  			d1->new.to = d2->new.to;
401  		}
402  	}
403  
404  	if (mflag)
405  		mergescript(j);
406  	else if (Aflag)
407  		Ascript(j);
408  	else if (eflag)
409  		edscript(j);
410  }
411  
412  /*
413   * The range of lines rold.from thru rold.to in file i is to be changed.
414   * It is to be printed only if it does not duplicate something to be
415   * printed later.
416   */
417  static void
418  change(int i, struct range *rold, bool dup)
419  {
420  
421  	printf("%d:", i);
422  	last[i] = rold->to;
423  	prange(rold, false);
424  	if (dup)
425  		return;
426  	i--;
427  	skip(i, rold->from, NULL);
428  	skip(i, rold->to, "  ");
429  }
430  
431  /*
432   * Print the range of line numbers, rold.from thru rold.to, as n1,n2 or
433   * n1.
434   */
435  static void
436  prange(struct range *rold, bool delete)
437  {
438  
439  	if (rold->to <= rold->from)
440  		printf("%da\n", rold->from - 1);
441  	else {
442  		printf("%d", rold->from);
443  		if (rold->to > rold->from + 1)
444  			printf(",%d", rold->to - 1);
445  		if (delete)
446  			printf("d\n");
447  		else
448  			printf("c\n");
449  	}
450  }
451  
452  /*
453   * No difference was reported by diff between file 1 (or 2) and file 3,
454   * and an artificial dummy difference (trange) must be ginned up to
455   * correspond to the change reported in the other file.
456   */
457  static void
458  keep(int i, struct range *rnew)
459  {
460  	int delta;
461  	struct range trange;
462  
463  	delta = last[3] - last[i];
464  	trange.from = rnew->from - delta;
465  	trange.to = rnew->to - delta;
466  	change(i, &trange, true);
467  }
468  
469  /*
470   * skip to just before line number from in file "i".  If "pr" is non-NULL,
471   * print all skipped stuff with string pr as a prefix.
472   */
473  static int
474  skip(int i, int from, const char *pr)
475  {
476  	size_t j, n;
477  	char *line;
478  
479  	for (n = 0; cline[i] < from - 1; n += j) {
480  		if ((line = get_line(fp[i], &j)) == NULL)
481  			errx(EXIT_FAILURE, "logic error");
482  		if (pr != NULL)
483  			printf("%s%s", Tflag == 1 ? "\t" : pr, line);
484  		cline[i]++;
485  	}
486  	return ((int) n);
487  }
488  
489  /*
490   * Return 1 or 0 according as the old range (in file 1) contains exactly
491   * the same data as the new range (in file 2).
492   */
493  static bool
494  duplicate(struct range *r1, struct range *r2)
495  {
496  	int c, d;
497  	int nchar;
498  	int nline;
499  
500  	if (r1->to-r1->from != r2->to-r2->from)
501  		return (0);
502  	skip(0, r1->from, NULL);
503  	skip(1, r2->from, NULL);
504  	nchar = 0;
505  	for (nline = 0; nline < r1->to - r1->from; nline++) {
506  		do {
507  			c = getc(fp[0]);
508  			d = getc(fp[1]);
509  			if (c == -1 && d == -1)
510  				break;
511  			if (c == -1 || d == -1)
512  				errx(EXIT_FAILURE, "logic error");
513  			nchar++;
514  			if (c != d) {
515  				repos(nchar);
516  				return (0);
517  			}
518  		} while (c != '\n');
519  	}
520  	repos(nchar);
521  	return (1);
522  }
523  
524  static void
525  repos(int nchar)
526  {
527  	int i;
528  
529  	for (i = 0; i < 2; i++)
530  		(void)fseek(fp[i], (long)-nchar, SEEK_CUR);
531  }
532  
533  /*
534   * collect an editing script for later regurgitation
535   */
536  static int
537  edit(struct diff *diff, bool dup, int j, int difftype)
538  {
539  	if (!(eflag == EFLAG_UNMERGED ||
540  		(!dup && eflag == EFLAG_OVERLAP ) ||
541  		(dup && eflag == EFLAG_NOOVERLAP))) {
542  		return (j);
543  	}
544  	j++;
545  	overlap[j] = !dup;
546  	if (!dup)
547  		overlapcnt++;
548  
549  	de[j].type = difftype;
550  #if DEBUG
551  	de[j].line = strdup(diff->line);
552  #endif	/* DEBUG */
553  
554  	de[j].old.from = diff->old.from;
555  	de[j].old.to = diff->old.to;
556  	de[j].new.from = diff->new.from;
557  	de[j].new.to = diff->new.to;
558  	return (j);
559  }
560  
561  static void
562  printrange(FILE *p, struct range *r)
563  {
564  	char *line = NULL;
565  	size_t len = 0;
566  	int i = 1;
567  	ssize_t rlen = 0;
568  
569  	/* We haven't been asked to print anything */
570  	if (r->from == r->to)
571  		return;
572  
573  	if (r->from > r->to)
574  		errx(EXIT_FAILURE, "invalid print range");
575  
576  	/*
577  	 * XXX-THJ: We read through all of the file for each range printed.
578  	 * This duplicates work and will probably impact performance on large
579  	 * files with lots of ranges.
580  	 */
581  	fseek(p, 0L, SEEK_SET);
582  	while ((rlen = getline(&line, &len, p)) > 0) {
583  		if (i >= r->from)
584  			printf("%s", line);
585  		if (++i > r->to - 1)
586  			break;
587  	}
588  	free(line);
589  }
590  
591  /* regurgitate */
592  static void
593  edscript(int n)
594  {
595  	bool delete;
596  	struct range *new, *old;
597  
598  	for (; n > 0; n--) {
599  		new = &de[n].new;
600  		old = &de[n].old;
601  
602  		delete = (new->from == new->to);
603  		if (!oflag || !overlap[n]) {
604  			prange(old, delete);
605  		} else {
606  			printf("%da\n", old->to - 1);
607  			printf("%s\n", divider);
608  		}
609  		printrange(fp[2], new);
610  		if (!oflag || !overlap[n]) {
611  			if (!delete)
612  				printf(".\n");
613  		} else {
614  			printf("%s %s\n.\n", newmark, f3mark);
615  			printf("%da\n%s %s\n.\n", old->from - 1,
616  				oldmark, f1mark);
617  		}
618  	}
619  	if (iflag)
620  		printf("w\nq\n");
621  
622  	exit(eflag == EFLAG_NONE ? overlapcnt : 0);
623  }
624  
625  /*
626   * Output an edit script to turn mine into yours, when there is a conflict
627   * between the 3 files bracket the changes. Regurgitate the diffs in reverse
628   * order to allow the ed script to track down where the lines are as changes
629   * are made.
630   */
631  static void
632  Ascript(int n)
633  {
634  	int startmark;
635  	bool deletenew;
636  	bool deleteold;
637  
638  	struct range *new, *old;
639  
640  	for (; n > 0; n--) {
641  		new = &de[n].new;
642  		old = &de[n].old;
643  		deletenew = (new->from == new->to);
644  		deleteold = (old->from == old->to);
645  
646  		if (de[n].type == DIFF_TYPE2) {
647  			if (!oflag || !overlap[n]) {
648  				prange(old, deletenew);
649  				printrange(fp[2], new);
650  			} else {
651  				startmark = new->to;
652  
653  				if (!deletenew)
654  					startmark--;
655  
656  				printf("%da\n", startmark);
657  				printf("%s %s\n", newmark, f3mark);
658  
659  				printf(".\n");
660  
661  				printf("%da\n", startmark -
662  					(new->to - new->from));
663  				printf("%s %s\n", oldmark, f2mark);
664  				if (!deleteold)
665  					printrange(fp[1], old);
666  				printf("%s\n.\n", divider);
667  			}
668  
669  		} else if (de[n].type == DIFF_TYPE3) {
670  			startmark = old->to - 1;
671  
672  			if (!oflag || !overlap[n]) {
673  				prange(old, deletenew);
674  				printrange(fp[2], new);
675  			} else {
676  				printf("%da\n", startmark);
677  				printf("%s %s\n", orgmark, f2mark);
678  
679  				if (deleteold) {
680  					struct range r;
681  					r.from = old->from-1;
682  					r.to = new->to;
683  					printrange(fp[1], &r);
684  				} else
685  					printrange(fp[1], old);
686  
687  				printf("%s\n", divider);
688  				printrange(fp[2], new);
689  			}
690  
691  			if (!oflag || !overlap[n]) {
692  				if (!deletenew)
693  					printf(".\n");
694  			} else {
695  				printf("%s %s\n.\n", newmark, f3mark);
696  
697  				/*
698  				 * Go to the start of the conflict in original
699  				 * file and append lines
700  				 */
701  				printf("%da\n%s %s\n.\n",
702  					startmark - (old->to - old->from),
703  					oldmark, f1mark);
704  			}
705  		}
706  	}
707  	if (iflag)
708  		printf("w\nq\n");
709  
710  	exit(overlapcnt > 0);
711  }
712  
713  /*
714   * Output the merged file directly (don't generate an ed script). When
715   * regurgitating diffs we need to walk forward through the file and print any
716   * inbetween lines.
717   */
718  static void
719  mergescript(int i)
720  {
721  	struct range r, *new, *old;
722  	int n;
723  
724  	r.from = 1;
725  	r.to = 1;
726  
727  	for (n = 1; n < i+1; n++) {
728  		new = &de[n].new;
729  		old = &de[n].old;
730  
731  		/* print any lines leading up to here */
732  		r.to = old->from;
733  		printrange(fp[0], &r);
734  
735  		if (de[n].type == DIFF_TYPE2) {
736  			printf("%s %s\n", oldmark, f2mark);
737  			printrange(fp[1], old);
738  			printf("%s\n", divider);
739  			printrange(fp[2], new);
740  			printf("%s %s\n", newmark, f3mark);
741  		} else if (de[n].type == DIFF_TYPE3) {
742  			if (!oflag || !overlap[n]) {
743  				printrange(fp[2], new);
744  			} else {
745  
746  				printf("%s %s\n", oldmark, f1mark);
747  				printrange(fp[0], old);
748  
749  				printf("%s %s\n", orgmark, f2mark);
750  				if (old->from == old->to) {
751  					struct range or;
752  					or.from = old->from - 1;
753  					or.to = new->to;
754  					printrange(fp[1], &or);
755  				} else
756  					printrange(fp[1], old);
757  
758  				printf("%s\n", divider);
759  
760  				printrange(fp[2], new);
761  				printf("%s %s\n", newmark, f3mark);
762  			}
763  		}
764  
765  		if (old->from == old->to)
766  			r.from = new->to;
767  		else
768  			r.from = old->to;
769  	}
770  	/*
771  	 * Print from the final range to the end of 'myfile'. Any deletions or
772  	 * additions to this file should have been handled by now.
773  	 *
774  	 * If the ranges are the same we need to rewind a line.
775  	 * If the new range is 0 length (from == to), we need to use the old
776  	 * range.
777  	 */
778  	new = &de[n-1].new;
779  	old = &de[n-1].old;
780  	if ((old->from == new->from) &&
781  		(old->to == new->to))
782  		r.from--;
783  	else if (new->from == new->to)
784  		r.from = old->from;
785  
786  	/*
787  	 * If the range is a 3 way merge then we need to skip a line in the
788  	 * trailing output.
789  	 */
790  	if (de[n-1].type == DIFF_TYPE3)
791  		r.from++;
792  
793  	r.to = INT_MAX;
794  	printrange(fp[0], &r);
795  	exit(overlapcnt > 0);
796  }
797  
798  static void
799  increase(void)
800  {
801  	struct diff *p;
802  	char *q;
803  	size_t newsz, incr;
804  
805  	/* are the memset(3) calls needed? */
806  	newsz = szchanges == 0 ? 64 : 2 * szchanges;
807  	incr = newsz - szchanges;
808  
809  	p = reallocarray(d13, newsz, sizeof(struct diff));
810  	if (p == NULL)
811  		err(1, NULL);
812  	memset(p + szchanges, 0, incr * sizeof(struct diff));
813  	d13 = p;
814  	p = reallocarray(d23, newsz, sizeof(struct diff));
815  	if (p == NULL)
816  		err(1, NULL);
817  	memset(p + szchanges, 0, incr * sizeof(struct diff));
818  	d23 = p;
819  	p = reallocarray(de, newsz, sizeof(struct diff));
820  	if (p == NULL)
821  		err(1, NULL);
822  	memset(p + szchanges, 0, incr * sizeof(struct diff));
823  	de = p;
824  	q = reallocarray(overlap, newsz, sizeof(char));
825  	if (q == NULL)
826  		err(1, NULL);
827  	memset(q + szchanges, 0, incr * sizeof(char));
828  	overlap = q;
829  	szchanges = newsz;
830  }
831  
832  
833  int
834  main(int argc, char **argv)
835  {
836  	int ch, nblabels, status, m, n, kq, nke, nleft, i;
837  	char *labels[] = { NULL, NULL, NULL };
838  	const char *diffprog = DIFF_PATH;
839  	char *file1, *file2, *file3;
840  	char *diffargv[7];
841  	int diffargc = 0;
842  	int fd13[2], fd23[2];
843  	int pd13, pd23;
844  	cap_rights_t rights_ro;
845  	struct kevent *e;
846  
847  	nblabels = 0;
848  	eflag = EFLAG_NONE;
849  	oflag = 0;
850  	diffargv[diffargc++] = __DECONST(char *, diffprog);
851  	while ((ch = getopt_long(argc, argv, OPTIONS, longopts, NULL)) != -1) {
852  		switch (ch) {
853  		case '3':
854  			eflag = EFLAG_NOOVERLAP;
855  			break;
856  		case 'a':
857  			diffargv[diffargc++] = __DECONST(char *, "-a");
858  			break;
859  		case 'A':
860  			Aflag = 1;
861  			break;
862  		case 'e':
863  			eflag = EFLAG_UNMERGED;
864  			break;
865  		case 'E':
866  			eflag = EFLAG_UNMERGED;
867  			oflag = 1;
868  			break;
869  		case 'i':
870  			iflag = 1;
871  			break;
872  		case 'L':
873  			oflag = 1;
874  			if (nblabels >= 3)
875  				errx(2, "too many file label options");
876  			labels[nblabels++] = optarg;
877  			break;
878  		case 'm':
879  			Aflag = 1;
880  			oflag = 1;
881  			mflag = 1;
882  			break;
883  		case 'T':
884  			Tflag = 1;
885  			break;
886  		case 'x':
887  			eflag = EFLAG_OVERLAP;
888  			break;
889  		case 'X':
890  			oflag = 1;
891  			eflag = EFLAG_OVERLAP;
892  			break;
893  		case DIFFPROG_OPT:
894  			diffprog = optarg;
895  			break;
896  		case STRIPCR_OPT:
897  			strip_cr = 1;
898  			diffargv[diffargc++] = __DECONST(char *, "--strip-trailing-cr");
899  			break;
900  		case HELP_OPT:
901  			usage();
902  			exit(0);
903  		case VERSION_OPT:
904  			printf("%s\n", diff3_version);
905  			exit(0);
906  		}
907  	}
908  	argc -= optind;
909  	argv += optind;
910  
911  	if (Aflag) {
912  		eflag = EFLAG_UNMERGED;
913  		oflag = 1;
914  	}
915  
916  	if (argc != 3) {
917  		usage();
918  		exit(2);
919  	}
920  
921  	if (caph_limit_stdio() == -1)
922  		err(2, "unable to limit stdio");
923  
924  	cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT, CAP_SEEK);
925  
926  	kq = kqueue();
927  	if (kq == -1)
928  		err(2, "kqueue");
929  
930  	e = malloc(2 * sizeof(struct kevent));
931  	if (e == NULL)
932  		err(2, "malloc");
933  
934  	/* TODO stdio */
935  	file1 = argv[0];
936  	file2 = argv[1];
937  	file3 = argv[2];
938  
939  	if (oflag) {
940  		asprintf(&f1mark, "%s",
941  		    labels[0] != NULL ? labels[0] : file1);
942  		if (f1mark == NULL)
943  			err(2, "asprintf");
944  		asprintf(&f2mark, "%s",
945  		    labels[1] != NULL ? labels[1] : file2);
946  		if (f2mark == NULL)
947  			err(2, "asprintf");
948  		asprintf(&f3mark, "%s",
949  		    labels[2] != NULL ? labels[2] : file3);
950  		if (f3mark == NULL)
951  			err(2, "asprintf");
952  	}
953  	fp[0] = fopen(file1, "r");
954  	if (fp[0] == NULL)
955  		err(2, "Can't open %s", file1);
956  	if (caph_rights_limit(fileno(fp[0]), &rights_ro) < 0)
957  		err(2, "unable to limit rights on: %s", file1);
958  
959  	fp[1] = fopen(file2, "r");
960  	if (fp[1] == NULL)
961  		err(2, "Can't open %s", file2);
962  	if (caph_rights_limit(fileno(fp[1]), &rights_ro) < 0)
963  		err(2, "unable to limit rights on: %s", file2);
964  
965  	fp[2] = fopen(file3, "r");
966  	if (fp[2] == NULL)
967  		err(2, "Can't open %s", file3);
968  	if (caph_rights_limit(fileno(fp[2]), &rights_ro) < 0)
969  		err(2, "unable to limit rights on: %s", file3);
970  
971  	if (pipe(fd13))
972  		err(2, "pipe");
973  	if (pipe(fd23))
974  		err(2, "pipe");
975  
976  	diffargv[diffargc] = file1;
977  	diffargv[diffargc + 1] = file3;
978  	diffargv[diffargc + 2] = NULL;
979  
980  	nleft = 0;
981  	pd13 = diffexec(diffprog, diffargv, fd13);
982  	EV_SET(e + nleft , pd13, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
983  	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
984  		err(2, "kevent1");
985  	nleft++;
986  
987  	diffargv[diffargc] = file2;
988  	pd23 = diffexec(diffprog, diffargv, fd23);
989  	EV_SET(e + nleft , pd23, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0, NULL);
990  	if (kevent(kq, e + nleft, 1, NULL, 0, NULL) == -1)
991  		err(2, "kevent2");
992  	nleft++;
993  
994  	caph_cache_catpages();
995  	if (caph_enter() < 0)
996  		err(2, "unable to enter capability mode");
997  
998  	/* parse diffs */
999  	increase();
1000  	m = readin(fd13[0], &d13);
1001  	n = readin(fd23[0], &d23);
1002  
1003  	/* waitpid cooked over pdforks */
1004  	while (nleft > 0) {
1005  		nke = kevent(kq, NULL, 0, e, nleft, NULL);
1006  		if (nke == -1)
1007  			err(2, "kevent");
1008  		for (i = 0; i < nke; i++) {
1009  			status = e[i].data;
1010  			if (WIFEXITED(status) && WEXITSTATUS(status) >= 2)
1011  				errx(2, "diff exited abnormally");
1012  			else if (WIFSIGNALED(status))
1013  				errx(2, "diff killed by signal %d",
1014  				    WTERMSIG(status));
1015  		}
1016  		nleft -= nke;
1017  	}
1018  	merge(m, n);
1019  
1020  	return (EXIT_SUCCESS);
1021  }
1022