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Date:: Fri Jul 1 21:13:24 2022 UTC
Message:: got patch: handle git-style diffs for the 3-way merge too tweak and ok stsp@
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1 /*
2  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  *
16  * Apply patches.
17  *
18  * Things that we may want to support:
19  *     + support indented patches?
20  *     + support other kinds of patches?
21  */
22 
23 #include <sys/types.h>
24 #include <sys/socket.h>
25 #include <sys/stat.h>
26 #include <sys/uio.h>
27 
28 #include <errno.h>
29 #include <limits.h>
30 #include <stdint.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_path.h"
39 #include "got_reference.h"
40 #include "got_cancel.h"
41 #include "got_worktree.h"
42 #include "got_repository.h"
43 #include "got_opentemp.h"
44 #include "got_patch.h"
45 
46 #include "got_lib_delta.h"
47 #include "got_lib_diff.h"
48 #include "got_lib_object.h"
49 #include "got_lib_privsep.h"
50 #include "got_lib_sha1.h"
51 
52 #define MIN(a, b) ((a) < (b) ? (a) : (b))
53 
54 struct got_patch_hunk {
55 	STAILQ_ENTRY(got_patch_hunk) entries;
56 	const struct got_error *err;
57 	int	offset;
58 	int	old_nonl;
59 	int	new_nonl;
60 	int	old_from;
61 	int	old_lines;
62 	int	new_from;
63 	int	new_lines;
64 	size_t	len;
65 	size_t	cap;
66 	char	**lines;
67 };
68 
69 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
70 struct got_patch {
71 	char	*old;
72 	char	*new;
73 	char	 cid[41];
74 	char	 blob[41];
75 	struct got_patch_hunk_head head;
76 };
77 
78 struct patch_args {
79 	got_patch_progress_cb progress_cb;
80 	void	*progress_arg;
81 	struct got_patch_hunk_head *head;
82 };
83 
84 static const struct got_error *
85 send_patch(struct imsgbuf *ibuf, int fd)
86 {
87 	const struct got_error *err = NULL;
88 
89 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
90 	    NULL, 0) == -1) {
91 		err = got_error_from_errno(
92 		    "imsg_compose GOT_IMSG_PATCH_FILE");
93 		close(fd);
94 		return err;
95 	}
96 
97 	if (imsg_flush(ibuf) == -1) {
98 		err = got_error_from_errno("imsg_flush");
99 		imsg_clear(ibuf);
100 	}
101 
102 	return err;
103 }
104 
105 static void
106 patch_free(struct got_patch *p)
107 {
108 	struct got_patch_hunk *h;
109 	size_t i;
110 
111 	while (!STAILQ_EMPTY(&p->head)) {
112 		h = STAILQ_FIRST(&p->head);
113 		STAILQ_REMOVE_HEAD(&p->head, entries);
114 
115 		for (i = 0; i < h->len; ++i)
116 			free(h->lines[i]);
117 		free(h->lines);
118 		free(h);
119 	}
120 
121 	free(p->new);
122 	free(p->old);
123 
124 	memset(p, 0, sizeof(*p));
125 	STAILQ_INIT(&p->head);
126 }
127 
128 static const struct got_error *
129 pushline(struct got_patch_hunk *h, const char *line)
130 {
131 	void 	*t;
132 	size_t	 newcap;
133 
134 	if (h->len == h->cap) {
135 		if ((newcap = h->cap * 1.5) == 0)
136 			newcap = 16;
137 		t = recallocarray(h->lines, h->cap, newcap,
138 		    sizeof(h->lines[0]));
139 		if (t == NULL)
140 			return got_error_from_errno("recallocarray");
141 		h->lines = t;
142 		h->cap = newcap;
143 	}
144 
145 	if ((t = strdup(line)) == NULL)
146 		return got_error_from_errno("strdup");
147 
148 	h->lines[h->len++] = t;
149 	return NULL;
150 }
151 
152 static const struct got_error *
153 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
154 {
155 	const struct got_error *err = NULL;
156 	struct imsg imsg;
157 	struct got_imsg_patch_hunk hdr;
158 	struct got_imsg_patch patch;
159 	struct got_patch_hunk *h = NULL;
160 	size_t datalen;
161 	int lastmode = -1;
162 
163 	memset(p, 0, sizeof(*p));
164 	STAILQ_INIT(&p->head);
165 
166 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
167 	if (err)
168 		return err;
169 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
170 		*done = 1;
171 		goto done;
172 	}
173 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
174 		err = got_error(GOT_ERR_PRIVSEP_MSG);
175 		goto done;
176 	}
177 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
178 	if (datalen != sizeof(patch)) {
179 		err = got_error(GOT_ERR_PRIVSEP_LEN);
180 		goto done;
181 	}
182 	memcpy(&patch, imsg.data, sizeof(patch));
183 
184 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
185 	    patch.new[sizeof(patch.new)-1] != '\0' ||
186 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
187 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
188 		err = got_error(GOT_ERR_PRIVSEP_LEN);
189 		goto done;
190 	}
191 
192 	if (*patch.cid != '\0')
193 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
194 
195 	if (*patch.blob != '\0')
196 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
197 
198 	/* automatically set strip=1 for git-style diffs */
199 	if (strip == -1 && patch.git &&
200 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
201 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
202 		strip = 1;
203 
204 	/* prefer the new name if not /dev/null for not git-style diffs */
205 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
206 		err = got_path_strip(&p->old, patch.new, strip);
207 		if (err)
208 			goto done;
209 	} else if (*patch.old != '\0') {
210 		err = got_path_strip(&p->old, patch.old, strip);
211 		if (err)
212 			goto done;
213 	}
214 
215 	if (*patch.new != '\0') {
216 		err = got_path_strip(&p->new, patch.new, strip);
217 		if (err)
218 			goto done;
219 	}
220 
221 	if (p->old == NULL && p->new == NULL) {
222 		err = got_error(GOT_ERR_PATCH_MALFORMED);
223 		goto done;
224 	}
225 
226 	imsg_free(&imsg);
227 
228 	for (;;) {
229 		char *t;
230 
231 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
232 		if (err) {
233 			patch_free(p);
234 			return err;
235 		}
236 
237 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
238 		switch (imsg.hdr.type) {
239 		case GOT_IMSG_PATCH_DONE:
240 			if (h != NULL && h->len == 0)
241 				err = got_error(GOT_ERR_PATCH_MALFORMED);
242 			goto done;
243 		case GOT_IMSG_PATCH_HUNK:
244 			if (h != NULL &&
245 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
246 				err = got_error(GOT_ERR_PATCH_MALFORMED);
247 				goto done;
248 			}
249 			lastmode = -1;
250 			if (datalen != sizeof(hdr)) {
251 				err = got_error(GOT_ERR_PRIVSEP_LEN);
252 				goto done;
253 			}
254 			memcpy(&hdr, imsg.data, sizeof(hdr));
255 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
256 				err = got_error(GOT_ERR_PRIVSEP_LEN);
257 				goto done;
258 			}
259 			if ((h = calloc(1, sizeof(*h))) == NULL) {
260 				err = got_error_from_errno("calloc");
261 				goto done;
262 			}
263 			h->old_from = hdr.oldfrom;
264 			h->old_lines = hdr.oldlines;
265 			h->new_from = hdr.newfrom;
266 			h->new_lines = hdr.newlines;
267 			STAILQ_INSERT_TAIL(&p->head, h, entries);
268 			break;
269 		case GOT_IMSG_PATCH_LINE:
270 			if (h == NULL) {
271 				err = got_error(GOT_ERR_PRIVSEP_MSG);
272 				goto done;
273 			}
274 			t = imsg.data;
275 			/* at least one char */
276 			if (datalen < 2 || t[datalen-1] != '\0') {
277 				err = got_error(GOT_ERR_PRIVSEP_MSG);
278 				goto done;
279 			}
280 			if (*t != ' ' && *t != '-' && *t != '+' &&
281 			    *t != '\\') {
282 				err = got_error(GOT_ERR_PRIVSEP_MSG);
283 				goto done;
284 			}
285 
286 			if (*t != '\\')
287 				err = pushline(h, t);
288 			else if (lastmode == '-')
289 				h->old_nonl = 1;
290 			else if (lastmode == '+')
291 				h->new_nonl = 1;
292 			else
293 				err = got_error(GOT_ERR_PATCH_MALFORMED);
294 
295 			if (err)
296 				goto done;
297 
298 			lastmode = *t;
299 			break;
300 		default:
301 			err = got_error(GOT_ERR_PRIVSEP_MSG);
302 			goto done;
303 		}
304 
305 		imsg_free(&imsg);
306 	}
307 
308 done:
309 	if (err)
310 		patch_free(p);
311 
312 	imsg_free(&imsg);
313 	return err;
314 }
315 
316 /*
317  * Copy data from orig starting at copypos until pos into tmp.
318  * If pos is -1, copy until EOF.
319  */
320 static const struct got_error *
321 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
322 {
323 	char buf[BUFSIZ];
324 	size_t len, r, w;
325 
326 	if (fseeko(orig, copypos, SEEK_SET) == -1)
327 		return got_error_from_errno("fseeko");
328 
329 	while (pos == -1 || copypos < pos) {
330 		len = sizeof(buf);
331 		if (pos > 0)
332 			len = MIN(len, (size_t)pos - copypos);
333 		r = fread(buf, 1, len, orig);
334 		if (r != len && ferror(orig))
335 			return got_error_from_errno("fread");
336 		w = fwrite(buf, 1, r, tmp);
337 		if (w != r)
338 			return got_error_from_errno("fwrite");
339 		copypos += len;
340 		if (r != len && feof(orig)) {
341 			if (pos == -1)
342 				return NULL;
343 			return got_error(GOT_ERR_HUNK_FAILED);
344 		}
345 	}
346 	return NULL;
347 }
348 
349 static const struct got_error *
350 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
351 {
352 	const struct got_error *err = NULL;
353 	char *line = NULL;
354 	char mode = *h->lines[0];
355 	size_t linesize = 0;
356 	ssize_t linelen;
357 	off_t match = -1;
358 	int match_lineno = -1;
359 
360 	for (;;) {
361 		linelen = getline(&line, &linesize, orig);
362 		if (linelen == -1) {
363 			if (ferror(orig))
364 				err = got_error_from_errno("getline");
365 			else if (match == -1)
366 				err = got_error(GOT_ERR_HUNK_FAILED);
367 			break;
368 		}
369 		if (line[linelen - 1] == '\n')
370 			line[linelen - 1] = '\0';
371 		(*lineno)++;
372 
373 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
374 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
375 		    (mode == '+' && *lineno == h->old_from)) {
376 			match = ftello(orig);
377 			if (match == -1) {
378 				err = got_error_from_errno("ftello");
379 				break;
380 			}
381 			match -= linelen;
382 			match_lineno = (*lineno)-1;
383 		}
384 
385 		if (*lineno >= h->old_from && match != -1)
386 			break;
387 	}
388 
389 	if (err == NULL) {
390 		*pos = match;
391 		*lineno = match_lineno;
392 		if (fseeko(orig, match, SEEK_SET) == -1)
393 			err = got_error_from_errno("fseeko");
394 	}
395 
396 	free(line);
397 	return err;
398 }
399 
400 static const struct got_error *
401 test_hunk(FILE *orig, struct got_patch_hunk *h)
402 {
403 	const struct got_error *err = NULL;
404 	char *line = NULL;
405 	size_t linesize = 0, i = 0;
406 	ssize_t linelen;
407 
408 	for (i = 0; i < h->len; ++i) {
409 		switch (*h->lines[i]) {
410 		case '+':
411 			continue;
412 		case ' ':
413 		case '-':
414 			linelen = getline(&line, &linesize, orig);
415 			if (linelen == -1) {
416 				if (ferror(orig))
417 					err = got_error_from_errno("getline");
418 				else
419 					err = got_error(
420 					    GOT_ERR_HUNK_FAILED);
421 				goto done;
422 			}
423 			if (line[linelen - 1] == '\n')
424 				line[linelen - 1] = '\0';
425 			if (strcmp(h->lines[i] + 1, line)) {
426 				err = got_error(GOT_ERR_HUNK_FAILED);
427 				goto done;
428 			}
429 			break;
430 		}
431 	}
432 
433 done:
434 	free(line);
435 	return err;
436 }
437 
438 static const struct got_error *
439 apply_hunk(FILE *tmp, struct got_patch_hunk *h, int *lineno)
440 {
441 	size_t i, new = 0;
442 
443 	for (i = 0; i < h->len; ++i) {
444 		switch (*h->lines[i]) {
445 		case ' ':
446 			if (fprintf(tmp, "%s\n", h->lines[i] + 1) < 0)
447 				return got_error_from_errno("fprintf");
448 			/* fallthrough */
449 		case '-':
450 			(*lineno)++;
451 			break;
452 		case '+':
453 			new++;
454 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0)
455 				return got_error_from_errno("fprintf");
456 			if (new != h->new_lines || !h->new_nonl) {
457 				if (fprintf(tmp, "\n") < 0)
458 					return got_error_from_errno(
459 					    "fprintf");
460 			}
461 			break;
462 		}
463 	}
464 	return NULL;
465 }
466 
467 static const struct got_error *
468 patch_file(struct got_patch *p, FILE *orig, FILE *tmp, mode_t *mode)
469 {
470 	const struct got_error *err = NULL;
471 	struct got_patch_hunk *h;
472 	struct stat sb;
473 	int lineno = 0;
474 	off_t copypos, pos;
475 	char *line = NULL;
476 	size_t linesize = 0;
477 	ssize_t linelen;
478 
479 	if (p->old == NULL) {				/* create */
480 		h = STAILQ_FIRST(&p->head);
481 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
482 			return got_error(GOT_ERR_PATCH_MALFORMED);
483 		return apply_hunk(tmp, h, &lineno);
484 	}
485 
486 	if (fstat(fileno(orig), &sb) == -1)
487 		return got_error_from_errno("fstat");
488 	*mode = sb.st_mode;
489 
490 	copypos = 0;
491 	STAILQ_FOREACH(h, &p->head, entries) {
492 	tryagain:
493 		err = locate_hunk(orig, h, &pos, &lineno);
494 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
495 			h->err = err;
496 		if (err != NULL)
497 			return err;
498 		err = copy(tmp, orig, copypos, pos);
499 		if (err != NULL)
500 			return err;
501 		copypos = pos;
502 
503 		err = test_hunk(orig, h);
504 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
505 			/*
506 			 * try to apply the hunk again starting the search
507 			 * after the previous partial match.
508 			 */
509 			if (fseeko(orig, pos, SEEK_SET) == -1)
510 				return got_error_from_errno("fseeko");
511 			linelen = getline(&line, &linesize, orig);
512 			if (linelen == -1)
513 				return got_error_from_errno("getline");
514 			lineno++;
515 			goto tryagain;
516 		}
517 		if (err != NULL)
518 			return err;
519 
520 		if (lineno + 1 != h->old_from)
521 			h->offset = lineno + 1 - h->old_from;
522 
523 		err = apply_hunk(tmp, h, &lineno);
524 		if (err != NULL)
525 			return err;
526 
527 		copypos = ftello(orig);
528 		if (copypos == -1)
529 			return got_error_from_errno("ftello");
530 	}
531 
532 	if (p->new == NULL && sb.st_size != copypos) {
533 		h = STAILQ_FIRST(&p->head);
534 		h->err = got_error(GOT_ERR_HUNK_FAILED);
535 		err = h->err;
536 	} else if (!feof(orig))
537 		err = copy(tmp, orig, copypos, -1);
538 
539 	return err;
540 }
541 
542 static const struct got_error *
543 report_progress(struct patch_args *pa, const char *old, const char *new,
544     unsigned char status, const struct got_error *orig_error)
545 {
546 	const struct got_error *err;
547 	struct got_patch_hunk *h;
548 
549 	err = pa->progress_cb(pa->progress_arg, old, new, status,
550 	    orig_error, 0, 0, 0, 0, 0, NULL);
551 	if (err)
552 		return err;
553 
554 	STAILQ_FOREACH(h, pa->head, entries) {
555 		if (h->offset == 0 && h->err == NULL)
556 			continue;
557 
558 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
559 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
560 		    h->offset, h->err);
561 		if (err)
562 			return err;
563 	}
564 
565 	return NULL;
566 }
567 
568 static const struct got_error *
569 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
570     const char *path)
571 {
572 	return report_progress(arg, path, NULL, status, NULL);
573 }
574 
575 static const struct got_error *
576 patch_add(void *arg, unsigned char status, const char *path)
577 {
578 	return report_progress(arg, NULL, path, status, NULL);
579 }
580 
581 static const struct got_error *
582 open_blob(char **path, FILE **fp, const char *blobid,
583     struct got_repository *repo)
584 {
585 	const struct got_error *err = NULL;
586 	struct got_blob_object *blob = NULL;
587 	struct got_object_id id, *idptr, *matched_id = NULL;
588 
589 	*fp = NULL;
590 	*path = NULL;
591 
592 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
593 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
594 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
595 		    repo);
596 		if (err)
597 			return err;
598 		idptr = matched_id;
599 	} else {
600 		if (!got_parse_sha1_digest(id.sha1, blobid))
601 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
602 		idptr = &id;
603 	}
604 
605 	err = got_object_open_as_blob(&blob, repo, idptr, 8192);
606 	if (err)
607 		goto done;
608 
609 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
610 	if (err)
611 		goto done;
612 
613 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
614 	if (err)
615 		goto done;
616 
617 done:
618 	if (blob)
619 		got_object_blob_close(blob);
620 	if (matched_id != NULL)
621 		free(matched_id);
622 	if (err) {
623 		if (*fp != NULL)
624 			fclose(*fp);
625 		if (*path != NULL)
626 			unlink(*path);
627 		free(*path);
628 		*fp = NULL;
629 		*path = NULL;
630 	}
631 	return err;
632 }
633 
634 static const struct got_error *
635 apply_patch(int *overlapcnt, struct got_worktree *worktree,
636     struct got_repository *repo, struct got_fileindex *fileindex,
637     const char *old, const char *new, struct got_patch *p, int nop,
638     struct patch_args *pa, got_cancel_cb cancel_cb, void *cancel_arg)
639 {
640 	const struct got_error *err = NULL;
641 	int do_merge = 0, file_renamed = 0;
642 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
643 	char *oldpath = NULL, *newpath = NULL;
644 	char *tmppath = NULL, *template = NULL, *parent = NULL;
645 	char *apath = NULL, *mergepath = NULL;
646 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
647 	int outfd;
648 	const char *outpath;
649 	mode_t mode = GOT_DEFAULT_FILE_MODE;
650 
651 	*overlapcnt = 0;
652 
653 	/* don't run the diff3 merge on creations/deletions */
654 	if (*p->blob != '\0' && p->old != NULL && p->new != NULL) {
655 		err = open_blob(&apath, &afile, p->blob, repo);
656 		/*
657 		 * ignore failures to open this blob, we might have
658 		 * parsed gibberish.
659 		 */
660 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
661 		    err->code != GOT_ERR_NO_OBJ)
662 			return err;
663 		else if (err == NULL)
664 			do_merge = 1;
665 		err = NULL;
666 	}
667 
668 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
669 	    old) == -1) {
670 		err = got_error_from_errno("asprintf");
671 		goto done;
672 	}
673 
674 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
675 	    new) == -1) {
676 		err = got_error_from_errno("asprintf");
677 		goto done;
678 	}
679 
680 	file_renamed = strcmp(oldpath, newpath);
681 
682 	if (asprintf(&template, "%s/got-patch",
683 	    got_worktree_get_root_path(worktree)) == -1) {
684 		err = got_error_from_errno(template);
685 		goto done;
686 	}
687 
688 	if (p->old != NULL && (oldfile = fopen(oldpath, "r")) == NULL) {
689 		err = got_error_from_errno2("open", oldpath);
690 		goto done;
691 	}
692 
693 	err = got_opentemp_named(&tmppath, &tmpfile, template);
694 	if (err)
695 		goto done;
696 	outpath = tmppath;
697 	outfd = fileno(tmpfile);
698 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile, &mode);
699 	if (err)
700 		goto done;
701 
702 	if (do_merge) {
703 		const char *type, *id;
704 
705 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
706 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
707 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
708 			err = got_error_from_errno("fseeko");
709 			goto done;
710 		}
711 
712 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
713 			err = got_error_from_errno("asprintf");
714 			oldlabel = NULL;
715 			goto done;
716 		}
717 
718 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
719 			err = got_error_from_errno("asprintf");
720 			newlabel = NULL;
721 			goto done;
722 		}
723 
724 		if (*p->cid != '\0') {
725 			type = "commit";
726 			id = p->cid;
727 		} else {
728 			type = "blob";
729 			id = p->blob;
730 		}
731 
732 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
733 			err = got_error_from_errno("asprintf");
734 			anclabel = NULL;
735 			goto done;
736 		}
737 
738 		err = got_opentemp_named(&mergepath, &mergefile, template);
739 		if (err)
740 			goto done;
741 		outpath = mergepath;
742 		outfd = fileno(mergefile);
743 
744 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
745 		    oldfile, oldlabel, anclabel, newlabel,
746 		    GOT_DIFF_ALGORITHM_PATIENCE);
747 		if (err)
748 			goto done;
749 	}
750 
751 	if (nop)
752 		goto done;
753 
754 	if (p->old != NULL && p->new == NULL) {
755 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
756 		    fileindex, patch_delete, pa);
757 		goto done;
758 	}
759 
760 	if (fchmod(outfd, mode) == -1) {
761 		err = got_error_from_errno2("chmod", tmppath);
762 		goto done;
763 	}
764 
765 	if (rename(outpath, newpath) == -1) {
766 		if (errno != ENOENT) {
767 			err = got_error_from_errno3("rename", outpath,
768 			    newpath);
769 			goto done;
770 		}
771 
772 		err = got_path_dirname(&parent, newpath);
773 		if (err != NULL)
774 			goto done;
775 		err = got_path_mkdir(parent);
776 		if (err != NULL)
777 			goto done;
778 		if (rename(outpath, newpath) == -1) {
779 			err = got_error_from_errno3("rename", outpath,
780 			    newpath);
781 			goto done;
782 		}
783 	}
784 
785 	if (file_renamed) {
786 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
787 		    fileindex, patch_delete, pa);
788 		if (err == NULL)
789 			err = got_worktree_patch_schedule_add(new, repo,
790 			    worktree, fileindex, patch_add,
791 			    pa);
792 		if (err)
793 			unlink(newpath);
794 	} else if (p->old == NULL) {
795 		err = got_worktree_patch_schedule_add(new, repo, worktree,
796 		    fileindex, patch_add, pa);
797 		if (err)
798 			unlink(newpath);
799 	} else if (*overlapcnt != 0)
800 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
801 	else if (do_merge)
802 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
803 	else
804 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
805 
806 done:
807 	free(parent);
808 	free(template);
809 
810 	if (tmppath != NULL)
811 		unlink(tmppath);
812 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
813 		err = got_error_from_errno("fclose");
814 	free(tmppath);
815 
816 	free(oldpath);
817 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
818 		err = got_error_from_errno("fclose");
819 
820 	if (apath != NULL)
821 		unlink(apath);
822 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
823 		err = got_error_from_errno("fclose");
824 	free(apath);
825 
826 	if (mergepath != NULL)
827 		unlink(mergepath);
828 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
829 		err = got_error_from_errno("fclose");
830 	free(mergepath);
831 
832 	free(newpath);
833 	free(oldlabel);
834 	free(newlabel);
835 	free(anclabel);
836 	return err;
837 }
838 
839 static void
840 reverse_patch(struct got_patch *p)
841 {
842 	struct got_patch_hunk *h;
843 	size_t i;
844 	int tmp;
845 
846 	STAILQ_FOREACH(h, &p->head, entries) {
847 		tmp = h->old_from;
848 		h->old_from = h->new_from;
849 		h->new_from = tmp;
850 
851 		tmp = h->old_lines;
852 		h->old_lines = h->new_lines;
853 		h->new_lines = tmp;
854 
855 		tmp = h->old_nonl;
856 		h->old_nonl = h->new_nonl;
857 		h->new_nonl = tmp;
858 
859 		for (i = 0; i < h->len; ++i) {
860 			if (*h->lines[i] == '+')
861 				*h->lines[i] = '-';
862 			else if (*h->lines[i] == '-')
863 				*h->lines[i] = '+';
864 		}
865 	}
866 }
867 
868 const struct got_error *
869 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
870     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
871     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
872 {
873 	const struct got_error *err = NULL, *complete_err = NULL;
874 	struct got_fileindex *fileindex = NULL;
875 	char *fileindex_path = NULL;
876 	char *oldpath, *newpath;
877 	struct imsgbuf *ibuf;
878 	int imsg_fds[2] = {-1, -1};
879 	int overlapcnt, done = 0, failed = 0;
880 	pid_t pid;
881 
882 	ibuf = calloc(1, sizeof(*ibuf));
883 	if (ibuf == NULL) {
884 		err = got_error_from_errno("calloc");
885 		goto done;
886 	}
887 
888 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
889 		err = got_error_from_errno("socketpair");
890 		goto done;
891 	}
892 
893 	pid = fork();
894 	if (pid == -1) {
895 		err = got_error_from_errno("fork");
896 		goto done;
897 	} else if (pid == 0) {
898 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
899 		    NULL);
900 		/* not reached */
901 	}
902 
903 	if (close(imsg_fds[1]) == -1) {
904 		err = got_error_from_errno("close");
905 		goto done;
906 	}
907 	imsg_fds[1] = -1;
908 	imsg_init(ibuf, imsg_fds[0]);
909 
910 	err = send_patch(ibuf, fd);
911 	fd = -1;
912 	if (err)
913 		goto done;
914 
915 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
916 	    worktree);
917 	if (err)
918 		goto done;
919 
920 	while (!done && err == NULL) {
921 		struct got_patch p;
922 		struct patch_args pa;
923 
924 		pa.progress_cb = progress_cb;
925 		pa.progress_arg = progress_arg;
926 		pa.head = &p.head;
927 
928 		err = recv_patch(ibuf, &done, &p, strip);
929 		if (err || done)
930 			break;
931 
932 		if (reverse)
933 			reverse_patch(&p);
934 
935 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
936 		    &newpath, worktree, repo, fileindex);
937 		if (err == NULL)
938 			err = apply_patch(&overlapcnt, worktree, repo,
939 			    fileindex, oldpath, newpath, &p, nop, &pa,
940 			    cancel_cb, cancel_arg);
941 		if (err != NULL) {
942 			failed = 1;
943 			/* recoverable errors */
944 			if (err->code == GOT_ERR_FILE_STATUS ||
945 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
946 				err = report_progress(&pa, p.old, p.new,
947 				    GOT_STATUS_CANNOT_UPDATE, err);
948 			else if (err->code == GOT_ERR_HUNK_FAILED)
949 				err = report_progress(&pa, p.old, p.new,
950 				    GOT_STATUS_CANNOT_UPDATE, NULL);
951 		}
952 		if (overlapcnt != 0)
953 			failed = 1;
954 
955 		free(oldpath);
956 		free(newpath);
957 		patch_free(&p);
958 
959 		if (err)
960 			break;
961 	}
962 
963 done:
964 	if (fileindex != NULL)
965 		complete_err = got_worktree_patch_complete(fileindex,
966 		    fileindex_path);
967 	if (complete_err && err == NULL)
968 		err = complete_err;
969 	free(fileindex_path);
970 	if (fd != -1 && close(fd) == -1 && err == NULL)
971 		err = got_error_from_errno("close");
972 	if (ibuf != NULL)
973 		imsg_clear(ibuf);
974 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
975 		err = got_error_from_errno("close");
976 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
977 		err = got_error_from_errno("close");
978 	if (err == NULL && failed)
979 		err = got_error(GOT_ERR_PATCH_FAILED);
980 	return err;
981 }