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Date:: Fri Jan 22 11:04:47 2021 UTC
Message:: make fclose(3) failure checks consistent; check 'fclose() == EOF' everywhere ok millert, naddy
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1 /*	$OpenBSD: diff3.c,v 1.41 2016/10/18 21:06:52 millert 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 #include <sys/stat.h>
68 #include <sys/queue.h>
69 
70 #include <ctype.h>
71 #include <limits.h>
72 #include <stdio.h>
73 #include <stdarg.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <time.h>
77 #include <unistd.h>
78 
79 #include "got_error.h"
80 #include "got_opentemp.h"
81 #include "got_object.h"
82 
83 #include "buf.h"
84 #include "rcsutil.h"
85 #include "got_lib_diff.h"
86 
87 #ifndef nitems
88 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
89 #endif
90 
91 /* diff3 - 3-way differential file comparison */
92 
93 /* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
94  *
95  * d13 = diff report on f1 vs f3
96  * d23 = diff report on f2 vs f3
97  * f1, f2, f3 the 3 files
98  * if changes in f1 overlap with changes in f3, m1 and m3 are used
99  * to mark the overlaps; otherwise, the file names f1 and f3 are used
100  * (only for options E and X).
101  */
102 
103 /*
104  * "from" is first in range of changed lines; "to" is last+1
105  * from=to=line after point of insertion for added lines.
106  */
107 struct line_range {
108 	int from;
109 	int to;
110 };
111 
112 struct off_range {
113 	off_t from;
114 	off_t to;
115 };
116 
117 struct diff {
118 	struct line_range old;
119 	struct line_range new;
120 	struct off_range oldo;
121 	struct off_range newo;
122 };
123 
124 struct diff3_state {
125 	size_t szchanges;
126 
127 	struct diff *d13;
128 	struct diff *d23;
129 
130 	/*
131 	 * "de" is used to gather editing scripts.  These are later spewed out
132 	 * in reverse order.  Its first element must be all zero, the "new"
133 	 * component of "de" contains line positions, and "oldo" and "newo"
134 	 * components contain byte positions.
135 	 * Array overlap indicates which sections in "de" correspond to lines
136 	 * that are different in all three files.
137 	 */
138 	struct diff *de;
139 	char *overlap;
140 	int overlapcnt;
141 	FILE *fp[3];
142 	int cline[3];		/* # of the last-read line in each file (0-2) */
143 
144 	/*
145 	 * the latest known correspondence between line numbers of the 3 files
146 	 * is stored in last[1-3];
147 	 */
148 	int last[4];
149 	char f1mark[PATH_MAX];
150 	char f2mark[PATH_MAX];
151 	char f3mark[PATH_MAX];
152 
153 	char *buf;
154 
155 	BUF *diffbuf;
156 };
157 
158 
159 static const struct got_error *duplicate(int *, int, struct line_range *,
160     struct line_range *, struct diff3_state *);
161 static const struct got_error *edit(struct diff *, int, int *,
162     struct diff3_state *);
163 static const struct got_error *getchange(char **, FILE *, struct diff3_state *);
164 static const struct got_error *get_line(char **, FILE *, size_t *,
165     struct diff3_state *);
166 static int number(char **);
167 static const struct got_error *readin(size_t *, char *, struct diff **,
168     struct diff3_state *);
169 static int ed_patch_lines(struct rcs_lines *, struct rcs_lines *);
170 static const struct got_error *skip(size_t *, int, int, struct diff3_state *);
171 static const struct got_error *edscript(int, struct diff3_state *);
172 static const struct got_error *merge(size_t, size_t, struct diff3_state *);
173 static const struct got_error *prange(struct line_range *, struct diff3_state *);
174 static const struct got_error *repos(int, struct diff3_state *);
175 static const struct got_error *increase(struct diff3_state *);
176 static const struct got_error *diff3_internal(char *, char *, char *,
177     char *, char *, const char *, const char *, struct diff3_state *,
178     const char *, const char *, const char *);
179 
180 static const struct got_error *
181 diff_output(BUF *diffbuf, const char *fmt, ...)
182 {
183 	const struct got_error *err = NULL;
184 	va_list vap;
185 	int i;
186 	char *str;
187 	size_t newsize;
188 
189 	va_start(vap, fmt);
190 	i = vasprintf(&str, fmt, vap);
191 	va_end(vap);
192 	if (i == -1)
193 		return got_error_from_errno("vasprintf");
194 	err = buf_append(&newsize, diffbuf, str, strlen(str));
195 	free(str);
196 	return err;
197 }
198 
199 static const struct got_error*
200 diffreg(BUF **d, const char *path1, const char *path2)
201 {
202 	const struct got_error *err = NULL;
203 	FILE *f1 = NULL, *f2 = NULL, *outfile = NULL;
204 	char *outpath = NULL;
205 	struct got_diffreg_result *diffreg_result = NULL;
206 
207 	*d = NULL;
208 
209 	f1 = fopen(path1, "r");
210 	if (f1 == NULL) {
211 		err = got_error_from_errno2("fopen", path1);
212 		goto done;
213 	}
214 	f2 = fopen(path2, "r");
215 	if (f1 == NULL) {
216 		err = got_error_from_errno2("fopen", path2);
217 		goto done;
218 	}
219 
220 	err = got_opentemp_named(&outpath, &outfile,
221 	    GOT_TMPDIR_STR "/got-diffreg");
222 	if (err)
223 		goto done;
224 
225 	err = got_diffreg(&diffreg_result, f1, f2,
226 	    GOT_DIFF_ALGORITHM_PATIENCE, 0, 1);
227 	if (err)
228 		goto done;
229 
230 	err = got_diffreg_output(NULL, NULL, diffreg_result, 1, 1, "", "",
231 	    GOT_DIFF_OUTPUT_EDSCRIPT, 0, outfile);
232 	if (err)
233 		goto done;
234 
235 	if (fflush(outfile) != 0) {
236 		err = got_error_from_errno2("fflush", outpath);
237 		goto done;
238 	}
239 
240 	err = buf_load(d, outpath);
241 done:
242 	if (outpath) {
243 		if (unlink(outpath) == -1 && err == NULL)
244 			err = got_error_from_errno2("unlink", outpath);
245 		free(outpath);
246 	}
247 	if (outfile && fclose(outfile) == EOF && err == NULL)
248 		err = got_error_from_errno("fclose");
249 	if (f1 && fclose(f1) == EOF && err == NULL)
250 		err = got_error_from_errno("fclose");
251 	if (f2 && fclose(f2) == EOF && err == NULL)
252 		err = got_error_from_errno("fclose");
253 	return err;
254 }
255 
256 /*
257  * For merge(1).
258  */
259 const struct got_error *
260 got_merge_diff3(int *overlapcnt, int outfd, const char *p1, const char *p2,
261     const char *p3, const char *label1, const char *label2, const char *label3)
262 {
263 	const struct got_error *err = NULL;
264 	char *dp13, *dp23, *path1, *path2, *path3;
265 	BUF *b1, *b2, *b3, *d1, *d2, *diffb;
266 	u_char *data, *patch;
267 	size_t dlen, plen, i;
268 	struct diff3_state *d3s;
269 
270 	*overlapcnt = 0;
271 
272 	d3s = calloc(1, sizeof(*d3s));
273 	if (d3s == NULL)
274 		return got_error_from_errno("calloc");
275 
276 	b1 = b2 = b3 = d1 = d2 = diffb = NULL;
277 	dp13 = dp23 = path1 = path2 = path3 = NULL;
278 	data = patch = NULL;
279 
280 	err = buf_load(&b1, p1);
281 	if (err)
282 		goto out;
283 	err = buf_load(&b2, p2);
284 	if (err)
285 		goto out;
286 	err = buf_load(&b3, p3);
287 	if (err)
288 		goto out;
289 
290 	err = buf_alloc(&diffb, 128);
291 	if (err)
292 		goto out;
293 
294 	if (asprintf(&path1, GOT_TMPDIR_STR "/got-diff1.XXXXXXXX") == -1) {
295 		err = got_error_from_errno("asprintf");
296 		goto out;
297 	}
298 	if (asprintf(&path2, GOT_TMPDIR_STR "/got-diff2.XXXXXXXX") == -1) {
299 		err = got_error_from_errno("asprintf");
300 		goto out;
301 	}
302 	if (asprintf(&path3, GOT_TMPDIR_STR "/got-diff3.XXXXXXXX") == -1) {
303 		err = got_error_from_errno("asprintf");
304 		goto out;
305 	}
306 
307 	err = buf_write_stmp(b1, path1);
308 	if (err)
309 		goto out;
310 	err = buf_write_stmp(b2, path2);
311 	if (err)
312 		goto out;
313 	err = buf_write_stmp(b3, path3);
314 	if (err)
315 		goto out;
316 
317 	buf_free(b2);
318 	b2 = NULL;
319 
320 	err = diffreg(&d1, path1, path3);
321 	if (err) {
322 		buf_free(diffb);
323 		diffb = NULL;
324 		goto out;
325 
326 	}
327 	err = diffreg(&d2, path2, path3);
328 	if (err) {
329 		buf_free(diffb);
330 		diffb = NULL;
331 		goto out;
332 	}
333 
334 	if (asprintf(&dp13, GOT_TMPDIR_STR "/got-d13.XXXXXXXXXX") == -1) {
335 		err = got_error_from_errno("asprintf");
336 		goto out;
337 	}
338 	err = buf_write_stmp(d1, dp13);
339 	if (err)
340 		goto out;
341 
342 	buf_free(d1);
343 	d1 = NULL;
344 
345 	if (asprintf(&dp23, GOT_TMPDIR_STR "/got-d23.XXXXXXXXXX") == -1) {
346 		err = got_error_from_errno("asprintf");
347 		goto out;
348 	}
349 	err = buf_write_stmp(d2, dp23);
350 	if (err)
351 		goto out;
352 
353 	buf_free(d2);
354 	d2 = NULL;
355 
356 	d3s->diffbuf = diffb;
357 	err = diff3_internal(dp13, dp23, path1, path2, path3,
358 	    label1, label3, d3s, label1, label2, label3);
359 	if (err) {
360 		buf_free(diffb);
361 		diffb = NULL;
362 		goto out;
363 	}
364 
365 	plen = buf_len(diffb);
366 	patch = buf_release(diffb);
367 	dlen = buf_len(b1);
368 	data = buf_release(b1);
369 
370 	diffb = rcs_patchfile(data, dlen, patch, plen, ed_patch_lines);
371 out:
372 	buf_free(b2);
373 	buf_free(b3);
374 	buf_free(d1);
375 	buf_free(d2);
376 
377 	if (unlink(path1) == -1 && err == NULL)
378 		err = got_error_from_errno2("unlink", path1);
379 	if (unlink(path2) == -1 && err == NULL)
380 		err = got_error_from_errno2("unlink", path2);
381 	if (unlink(path3) == -1 && err == NULL)
382 		err = got_error_from_errno2("unlink", path3);
383 	if (unlink(dp13) == -1 && err == NULL)
384 		err = got_error_from_errno2("unlink", dp13);
385 	if (unlink(dp23) == -1 && err == NULL)
386 		err = got_error_from_errno2("unlink", dp23);
387 
388 	free(path1);
389 	free(path2);
390 	free(path3);
391 	free(dp13);
392 	free(dp23);
393 	free(data);
394 	free(patch);
395 
396 	for (i = 0; i < nitems(d3s->fp); i++) {
397 		if (d3s->fp[i] && fclose(d3s->fp[i]) == EOF && err == NULL)
398 			err = got_error_from_errno("fclose");
399 	}
400 	if (err == NULL && diffb) {
401 		if (buf_write_fd(diffb, outfd) < 0)
402 			err = got_error_from_errno("buf_write_fd");
403 		*overlapcnt = d3s->overlapcnt;
404 	}
405 	free(d3s);
406 	buf_free(diffb);
407 	return err;
408 }
409 
410 static const struct got_error *
411 diff3_internal(char *dp13, char *dp23, char *path1, char *path2, char *path3,
412     const char *fmark, const char *rmark, struct diff3_state *d3s,
413     const char *label1, const char *label2, const char *label3)
414 {
415 	const struct got_error *err = NULL;
416 	ssize_t m, n;
417 	int i;
418 
419 	i = snprintf(d3s->f1mark, sizeof(d3s->f1mark),
420 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_BEGIN,
421 	    label1 ? " " : "", label1 ? label1 : "");
422 	if (i < 0 || i >= (int)sizeof(d3s->f1mark))
423 		return got_error(GOT_ERR_NO_SPACE);
424 
425 	i = snprintf(d3s->f2mark, sizeof(d3s->f2mark),
426 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_ORIG,
427 	    label2 ? " " : "", label2 ? label2 : "");
428 	if (i < 0 || i >= (int)sizeof(d3s->f2mark))
429 		return got_error(GOT_ERR_NO_SPACE);
430 
431 	i = snprintf(d3s->f3mark, sizeof(d3s->f3mark),
432 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_END,
433 	    label3 ? " " : "", label3 ? label3 : "");
434 	if (i < 0 || i >= (int)sizeof(d3s->f3mark))
435 		return got_error(GOT_ERR_NO_SPACE);
436 
437 	err = increase(d3s);
438 	if (err)
439 		return err;
440 
441 	err = readin(&m, dp13, &d3s->d13, d3s);
442 	if (err)
443 		return err;
444 	err = readin(&n, dp23, &d3s->d23, d3s);
445 	if (err)
446 		return err;
447 
448 	if ((d3s->fp[0] = fopen(path1, "r")) == NULL)
449 		return got_error_from_errno2("fopen", path1);
450 	if ((d3s->fp[1] = fopen(path2, "r")) == NULL)
451 		return got_error_from_errno2("fopen", path2);
452 	if ((d3s->fp[2] = fopen(path3, "r")) == NULL)
453 		return got_error_from_errno2("fopen", path3);
454 
455 	return merge(m, n, d3s);
456 }
457 
458 static int
459 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
460 {
461 	char op, *ep;
462 	struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
463 	int start, end, i, lineno;
464 	u_char tmp;
465 
466 	dlp = TAILQ_FIRST(&(dlines->l_lines));
467 	lp = TAILQ_FIRST(&(plines->l_lines));
468 
469 	end = 0;
470 	for (lp = TAILQ_NEXT(lp, l_list); lp != NULL;
471 	    lp = TAILQ_NEXT(lp, l_list)) {
472 		/* Skip blank lines */
473 		if (lp->l_len < 2)
474 			continue;
475 
476 		/* NUL-terminate line buffer for strtol() safety. */
477 		tmp = lp->l_line[lp->l_len - 1];
478 		lp->l_line[lp->l_len - 1] = '\0';
479 
480 		/* len - 1 is NUL terminator so we use len - 2 for 'op' */
481 		op = lp->l_line[lp->l_len - 2];
482 		start = (int)strtol(lp->l_line, &ep, 10);
483 
484 		/* Restore the last byte of the buffer */
485 		lp->l_line[lp->l_len - 1] = tmp;
486 
487 		if (op == 'a') {
488 			if (start > dlines->l_nblines ||
489 			    start < 0 || *ep != 'a')
490 				return -1;
491 		} else if (op == 'c') {
492 			if (start > dlines->l_nblines ||
493 			    start < 0 || (*ep != ',' && *ep != 'c'))
494 				return -1;
495 
496 			if (*ep == ',') {
497 				ep++;
498 				end = (int)strtol(ep, &ep, 10);
499 				if (end < 0 || *ep != 'c')
500 					return -1;
501 			} else {
502 				end = start;
503 			}
504 		}
505 
506 
507 		for (;;) {
508 			if (dlp == NULL)
509 				break;
510 			if (dlp->l_lineno == start)
511 				break;
512 			if (dlp->l_lineno > start) {
513 				dlp = TAILQ_PREV(dlp, tqh, l_list);
514 			} else if (dlp->l_lineno < start) {
515 				ndlp = TAILQ_NEXT(dlp, l_list);
516 				if (ndlp->l_lineno > start)
517 					break;
518 				dlp = ndlp;
519 			}
520 		}
521 
522 		if (dlp == NULL)
523 			return -1;
524 
525 
526 		if (op == 'c') {
527 			insert_after = TAILQ_PREV(dlp, tqh, l_list);
528 			for (i = 0; i <= (end - start); i++) {
529 				ndlp = TAILQ_NEXT(dlp, l_list);
530 				TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list);
531 				dlp = ndlp;
532 			}
533 			dlp = insert_after;
534 		}
535 
536 		if (op == 'a' || op == 'c') {
537 			for (;;) {
538 				ndlp = lp;
539 				lp = TAILQ_NEXT(lp, l_list);
540 				if (lp == NULL)
541 					return -1;
542 
543 				if (lp->l_len == 2 &&
544 				    lp->l_line[0] == '.' &&
545 				    lp->l_line[1] == '\n')
546 					break;
547 
548 				TAILQ_REMOVE(&(plines->l_lines), lp, l_list);
549 				TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,
550 				    lp, l_list);
551 				dlp = lp;
552 
553 				lp->l_lineno = start;
554 				lp = ndlp;
555 			}
556 		}
557 
558 		/*
559 		 * always resort lines as the markers might be put at the
560 		 * same line as we first started editing.
561 		 */
562 		lineno = 0;
563 		TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)
564 			sort->l_lineno = lineno++;
565 		dlines->l_nblines = lineno - 1;
566 	}
567 
568 	return (0);
569 }
570 
571 /*
572  * Pick up the line numbers of all changes from one change file.
573  * (This puts the numbers in a vector, which is not strictly necessary,
574  * since the vector is processed in one sequential pass.
575  * The vector could be optimized out of existence)
576  */
577 static const struct got_error *
578 readin(size_t *n, char *name, struct diff **dd, struct diff3_state *d3s)
579 {
580 	const struct got_error *err = NULL;
581 	FILE *f;
582 	int a, b, c, d;
583 	char kind, *p;
584 	size_t i = 0;
585 
586 	*n = 0;
587 
588 	f = fopen(name, "r");
589 	if (f == NULL)
590 		return got_error_from_errno2("fopen", name);
591 	err = getchange(&p, f, d3s);
592 	if (err)
593 		goto done;
594 	for (i = 0; p; i++) {
595 		if (i >= d3s->szchanges - 1) {
596 			err = increase(d3s);
597 			if (err)
598 				goto done;
599 		}
600 		a = b = number(&p);
601 		if (*p == ',') {
602 			p++;
603 			b = number(&p);
604 		}
605 		kind = *p++;
606 		c = d = number(&p);
607 		if (*p == ',') {
608 			p++;
609 			d = number(&p);
610 		}
611 		if (kind == 'a')
612 			a++;
613 		if (kind == 'd')
614 			c++;
615 		b++;
616 		d++;
617 		(*dd)[i].old.from = a;
618 		(*dd)[i].old.to = b;
619 		(*dd)[i].new.from = c;
620 		(*dd)[i].new.to = d;
621 
622 		err = getchange(&p, f, d3s);
623 		if (err)
624 			goto done;
625 	}
626 
627 	if (i) {
628 		(*dd)[i].old.from = (*dd)[i - 1].old.to;
629 		(*dd)[i].new.from = (*dd)[i - 1].new.to;
630 	}
631 done:
632 	if (fclose(f) == EOF && err == NULL)
633 		err = got_error_from_errno("fclose");
634 	if (err == NULL)
635 		*n = i;
636 	return err;
637 }
638 
639 static int
640 number(char **lc)
641 {
642 	int nn;
643 
644 	nn = 0;
645 	while (isdigit((unsigned char)(**lc)))
646 		nn = nn*10 + *(*lc)++ - '0';
647 
648 	return (nn);
649 }
650 
651 static const struct got_error *
652 getchange(char **line, FILE *b, struct diff3_state *d3s)
653 {
654 	const struct got_error *err = NULL;
655 
656 	*line = NULL;
657 	do {
658 		if (*line && isdigit((unsigned char)(*line)[0]))
659 			return NULL;
660 		err = get_line(line, b, NULL, d3s);
661 		if (err)
662 			return err;
663 	} while (*line);
664 
665 	return NULL;
666 }
667 
668 static const struct got_error *
669 get_line(char **ret, FILE *b, size_t *n, struct diff3_state *d3s)
670 {
671 	const struct got_error *err = NULL;
672 	char *cp = NULL;
673 	size_t size;
674 	ssize_t len;
675 	char *new;
676 
677 	*ret = NULL;
678 
679 	len = getline(&cp, &size, b);
680 	if (len == -1) {
681 		if (ferror(b))
682 			err = got_error_from_errno("getline");
683 		goto done;
684 	}
685 
686 	if (cp[len - 1] != '\n') {
687 		len++;
688 		if (len + 1 > size) {
689 			new = realloc(cp, len + 1);
690 			if (new == NULL) {
691 				err = got_error_from_errno("realloc");
692 				goto done;
693 			}
694 			cp = new;
695 		}
696 		cp[len - 1] = '\n';
697 		cp[len] = '\0';
698 	}
699 
700 	free(d3s->buf);
701 	*ret = d3s->buf = cp;
702 	cp = NULL;
703 	if (n != NULL)
704 		*n = len;
705 done:
706 	free(cp);
707 	return err;
708 }
709 
710 static const struct got_error *
711 merge(size_t m1, size_t m2, struct diff3_state *d3s)
712 {
713 	const struct got_error *err = NULL;
714 	struct diff *d1, *d2;
715 	int dpl, j, t1, t2;
716 
717 	d1 = d3s->d13;
718 	d2 = d3s->d23;
719 	j = 0;
720 	for (;;) {
721 		t1 = (d1 < d3s->d13 + m1);
722 		t2 = (d2 < d3s->d23 + m2);
723 		if (!t1 && !t2)
724 			break;
725 
726 		/* first file is different from others */
727 		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
728 			/* stuff peculiar to 1st file */
729 			d1++;
730 			continue;
731 		}
732 
733 		/* second file is different from others */
734 		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
735 			d2++;
736 			continue;
737 		}
738 
739 		/*
740 		 * Merge overlapping changes in first file
741 		 * this happens after extension (see below).
742 		 */
743 		if (d1 + 1 < d3s->d13 + m1 && d1->new.to >= d1[1].new.from) {
744 			d1[1].old.from = d1->old.from;
745 			d1[1].new.from = d1->new.from;
746 			d1++;
747 			continue;
748 		}
749 
750 		/* merge overlapping changes in second */
751 		if (d2 + 1 < d3s->d23 + m2 && d2->new.to >= d2[1].new.from) {
752 			d2[1].old.from = d2->old.from;
753 			d2[1].new.from = d2->new.from;
754 			d2++;
755 			continue;
756 		}
757 		/* stuff peculiar to third file or different in all */
758 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
759 			err = duplicate(&dpl, j, &d1->old, &d2->old, d3s);
760 			if (err)
761 				return err;
762 
763 			/*
764 			 * dpl = 0 means all files differ
765 			 * dpl = 1 means files 1 and 2 identical
766 			 */
767 			err = edit(d1, dpl, &j, d3s);
768 			if (err)
769 				return err;
770 			d1++;
771 			d2++;
772 			continue;
773 		}
774 
775 		/*
776 		 * Overlapping changes from file 1 and 2; extend changes
777 		 * appropriately to make them coincide.
778 		 */
779 		if (d1->new.from < d2->new.from) {
780 			d2->old.from -= d2->new.from - d1->new.from;
781 			d2->new.from = d1->new.from;
782 		} else if (d2->new.from < d1->new.from) {
783 			d1->old.from -= d1->new.from - d2->new.from;
784 			d1->new.from = d2->new.from;
785 		}
786 		if (d1->new.to > d2->new.to) {
787 			d2->old.to += d1->new.to - d2->new.to;
788 			d2->new.to = d1->new.to;
789 		} else if (d2->new.to > d1->new.to) {
790 			d1->old.to += d2->new.to - d1->new.to;
791 			d1->new.to = d2->new.to;
792 		}
793 	}
794 
795 	return (edscript(j, d3s));
796 }
797 
798 /*
799  * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
800  */
801 static const struct got_error *
802 prange(struct line_range *rold, struct diff3_state *d3s)
803 {
804 	const struct got_error *err = NULL;
805 
806 	if (rold->to <= rold->from) {
807 		err = diff_output(d3s->diffbuf, "%da\n", rold->from - 1);
808 		if (err)
809 			return err;
810 	} else {
811 		err = diff_output(d3s->diffbuf, "%d", rold->from);
812 		if (err)
813 			return err;
814 		if (rold->to > rold->from + 1) {
815 			err = diff_output(d3s->diffbuf, ",%d", rold->to - 1);
816 			if (err)
817 				return err;
818 		}
819 		err = diff_output(d3s->diffbuf, "c\n");
820 		if (err)
821 			return err;
822 	}
823 
824 	return NULL;
825 }
826 
827 /*
828  * Skip to just before line number from in file "i".
829  * Return the number of bytes skipped in *nskipped.
830  */
831 static const struct got_error *
832 skip(size_t *nskipped, int i, int from, struct diff3_state *d3s)
833 {
834 	const struct got_error *err = NULL;
835 	size_t len, n;
836 	char *line;
837 
838 	*nskipped = 0;
839 	for (n = 0; d3s->cline[i] < from - 1; n += len) {
840 		err = get_line(&line, d3s->fp[i], &len, d3s);
841 		if (err)
842 			return err;
843 		d3s->cline[i]++;
844 	}
845 	*nskipped = n;
846 	return NULL;
847 }
848 
849 /*
850  * Set *dpl to 1 or 0 according as the old range (in file 1) contains exactly
851  * the same data as the new range (in file 2).
852  *
853  * If this change could overlap, remember start/end offsets in file 2 so we
854  * can write out the original lines of text if a merge conflict occurs.
855  */
856 static const struct got_error *
857 duplicate(int *dpl, int j, struct line_range *r1, struct line_range *r2,
858     struct diff3_state *d3s)
859 {
860 	const struct got_error *err = NULL;
861 	int c,d;
862 	int nchar;
863 	int nline;
864 	size_t nskipped;
865 	off_t off;
866 
867 	*dpl = 0;
868 
869 	if (r1->to - r1->from != r2->to - r2->from)
870 		return NULL;
871 
872 	err = skip(&nskipped, 0, r1->from, d3s);
873 	if (err)
874 		return err;
875 	err = skip(&nskipped, 1, r2->from, d3s);
876 	if (err)
877 		return err;
878 
879 	off = ftello(d3s->fp[1]);
880 	if (off == -1)
881 		return got_error_from_errno("ftello");
882 	d3s->de[j + 1].oldo.from = off; /* original lines start here */
883 
884 	nchar = 0;
885 	for (nline = 0; nline < r1->to - r1->from; nline++) {
886 		do {
887 			c = getc(d3s->fp[0]);
888 			if (c == EOF)
889 				return got_ferror(d3s->fp[0], GOT_ERR_EOF);
890 			d = getc(d3s->fp[1]);
891 			if (d == EOF)
892 				return got_ferror(d3s->fp[1], GOT_ERR_EOF);
893 			nchar++;
894 			if (c != d) {
895 				long orig_line_len = nchar;
896 				while (d != '\n') {
897 					d = getc(d3s->fp[1]);
898 					if (d == EOF)
899 						break;
900 					orig_line_len++;
901 				}
902 				if (orig_line_len > nchar &&
903 				    fseek(d3s->fp[1], -(orig_line_len - nchar),
904 				    SEEK_CUR) == -1)
905 					return got_ferror(d3s->fp[1],
906 						GOT_ERR_IO);
907  				/* original lines end here */
908 				d3s->de[j + 1].oldo.to = off + orig_line_len;
909 				err = repos(nchar, d3s);
910 				if (err)
911 					return err;
912 				return NULL;
913 			}
914 		} while (c != '\n');
915 	}
916 	err = repos(nchar, d3s);
917 	if (err)
918 		return err;
919 	*dpl = 1;
920 	return NULL;
921 }
922 
923 static const struct got_error *
924 repos(int nchar, struct diff3_state *d3s)
925 {
926 	int i;
927 
928 	for (i = 0; i < 2; i++) {
929 		if (fseek(d3s->fp[i], (long)-nchar, SEEK_CUR) == -1)
930 			return got_ferror(d3s->fp[i], GOT_ERR_IO);
931 	}
932 
933 	return NULL;
934 }
935 
936 /*
937  * collect an editing script for later regurgitation
938  */
939 static const struct got_error *
940 edit(struct diff *diff, int fdup, int *j, struct diff3_state *d3s)
941 {
942 	const struct got_error *err = NULL;
943 	size_t nskipped;
944 
945 	if (((fdup + 1) & 3) == 0)
946 		return NULL;
947 	(*j)++;
948 	d3s->overlap[*j] = !fdup;
949 	if (!fdup)
950 		d3s->overlapcnt++;
951 	d3s->de[*j].old.from = diff->old.from;
952 	d3s->de[*j].old.to = diff->old.to;
953 
954 	err = skip(&nskipped, 2, diff->new.from, d3s);
955 	if (err)
956 		return err;
957 	d3s->de[*j].newo.from = d3s->de[*j - 1].newo.to + nskipped;
958 
959 	err = skip(&nskipped, 2, diff->new.to, d3s);
960 	if (err)
961 		return err;
962 	d3s->de[*j].newo.to = d3s->de[*j].newo.from + nskipped;
963 	return NULL;
964 }
965 
966 /* regurgitate */
967 static const struct got_error *
968 edscript(int n, struct diff3_state *d3s)
969 {
970 	const struct got_error *err = NULL;
971 	size_t k, len;
972 	char block[BUFSIZ+1];
973 
974 	for (; n > 0; n--) {
975 		if (!d3s->overlap[n]) {
976 			err = prange(&d3s->de[n].old, d3s);
977 			if (err)
978 				return err;
979 		} else if (d3s->de[n].oldo.from < d3s->de[n].oldo.to) {
980 			/* Output a block of 3-way diff base file content. */
981 			err = diff_output(d3s->diffbuf, "%da\n%s\n",
982 			    d3s->de[n].old.to - 1, d3s->f2mark);
983 			if (err)
984 				return err;
985 			if (fseeko(d3s->fp[1], d3s->de[n].oldo.from, SEEK_SET)
986 			    == -1)
987 				return got_error_from_errno("fseeko");
988 			k = (size_t)(d3s->de[n].oldo.to - d3s->de[n].oldo.from);
989 			for (; k > 0; k -= len) {
990 				size_t r;
991 				len = k > BUFSIZ ? BUFSIZ : k;
992 				r = fread(block, 1, len, d3s->fp[1]);
993 				if (r == 0) {
994 					if (feof(d3s->fp[1]))
995 						break;
996 					return got_ferror(d3s->fp[1],
997 					    GOT_ERR_IO);
998 				}
999 				if (r != len)
1000 					len = r;
1001 				block[len] = '\0';
1002 				err = diff_output(d3s->diffbuf, "%s", block);
1003 				if (err)
1004 					return err;
1005 			}
1006 			err = diff_output(d3s->diffbuf, "%s\n",
1007 			    GOT_DIFF_CONFLICT_MARKER_SEP);
1008 			if (err)
1009 				return err;
1010  		} else {
1011  			err = diff_output(d3s->diffbuf, "%da\n%s\n",
1012 			    d3s->de[n].old.to -1, GOT_DIFF_CONFLICT_MARKER_SEP);
1013 			if (err)
1014 				return err;
1015 		}
1016 		if (fseeko(d3s->fp[2], d3s->de[n].newo.from, SEEK_SET)
1017 		    == -1)
1018 			return got_error_from_errno("fseek");
1019 		k = (size_t)(d3s->de[n].newo.to - d3s->de[n].newo.from);
1020 		for (; k > 0; k -= len) {
1021 			size_t r;
1022 			len = k > BUFSIZ ? BUFSIZ : k;
1023 			r = fread(block, 1, len, d3s->fp[2]);
1024 			if (r == 0) {
1025 				if (feof(d3s->fp[2]))
1026 					break;
1027 				return got_ferror(d3s->fp[2],
1028 				    GOT_ERR_IO);
1029 			}
1030 			if (r != len)
1031 				len = r;
1032 			block[len] = '\0';
1033 			err = diff_output(d3s->diffbuf, "%s", block);
1034 			if (err)
1035 				return err;
1036 		}
1037 
1038 		if (!d3s->overlap[n]) {
1039 			err = diff_output(d3s->diffbuf, ".\n");
1040 			if (err)
1041 				return err;
1042 		} else {
1043 			err = diff_output(d3s->diffbuf, "%s\n.\n", d3s->f3mark);
1044 			if (err)
1045 				return err;
1046 			err = diff_output(d3s->diffbuf, "%da\n%s\n.\n",
1047 			    d3s->de[n].old.from - 1, d3s->f1mark);
1048 			if (err)
1049 				return err;
1050 		}
1051 	}
1052 
1053 	return NULL;
1054 }
1055 
1056 static const struct got_error *
1057 increase(struct diff3_state *d3s)
1058 {
1059 	size_t newsz, incr;
1060 	struct diff *d;
1061 	char *s;
1062 
1063 	/* are the memset(3) calls needed? */
1064 	newsz = d3s->szchanges == 0 ? 64 : 2 * d3s->szchanges;
1065 	incr = newsz - d3s->szchanges;
1066 
1067 	d = reallocarray(d3s->d13, newsz, sizeof(*d3s->d13));
1068 	if (d == NULL)
1069 		return got_error_from_errno("reallocarray");
1070 	d3s->d13 = d;
1071 	memset(d3s->d13 + d3s->szchanges, 0, incr * sizeof(*d3s->d13));
1072 
1073 	d = reallocarray(d3s->d23, newsz, sizeof(*d3s->d23));
1074 	if (d == NULL)
1075 		return got_error_from_errno("reallocarray");
1076 	d3s->d23 = d;
1077 	memset(d3s->d23 + d3s->szchanges, 0, incr * sizeof(*d3s->d23));
1078 
1079 	d = reallocarray(d3s->de, newsz, sizeof(*d3s->de));
1080 	if (d == NULL)
1081 		return got_error_from_errno("reallocarray");
1082 	d3s->de = d;
1083 	memset(d3s->de + d3s->szchanges, 0, incr * sizeof(*d3s->de));
1084 
1085 	s = reallocarray(d3s->overlap, newsz, sizeof(*d3s->overlap));
1086 	if (s == NULL)
1087 		return got_error_from_errno("reallocarray");
1088 	d3s->overlap = s;
1089 	memset(d3s->overlap + d3s->szchanges, 0, incr * sizeof(*d3s->overlap));
1090 	d3s->szchanges = newsz;
1091 
1092 	return NULL;
1093 }