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/queue.h>
25 #include <sys/socket.h>
26 #include <sys/stat.h>
27 #include <sys/uio.h>
28 
29 #include <ctype.h>
30 #include <errno.h>
31 #include <limits.h>
32 #include <sha1.h>
33 #include <stdint.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <imsg.h>
39 
40 #include "got_error.h"
41 #include "got_object.h"
42 #include "got_path.h"
43 #include "got_reference.h"
44 #include "got_cancel.h"
45 #include "got_worktree.h"
46 #include "got_repository.h"
47 #include "got_opentemp.h"
48 #include "got_patch.h"
49 #include "got_diff.h"
50 
51 #include "got_lib_delta.h"
52 #include "got_lib_diff.h"
53 #include "got_lib_object.h"
54 #include "got_lib_privsep.h"
55 #include "got_lib_sha1.h"
56 
57 #define MIN(a, b) ((a) < (b) ? (a) : (b))
58 
59 struct got_patch_hunk {
60 	STAILQ_ENTRY(got_patch_hunk) entries;
61 	const struct got_error *err;
62 	int	ws_mangled;
63 	int	offset;
64 	int	old_nonl;
65 	int	new_nonl;
66 	int	old_from;
67 	int	old_lines;
68 	int	new_from;
69 	int	new_lines;
70 	size_t	len;
71 	size_t	cap;
72 	char	**lines;
73 };
74 
75 STAILQ_HEAD(got_patch_hunk_head, got_patch_hunk);
76 struct got_patch {
77 	char	*old;
78 	char	*new;
79 	char	 cid[41];
80 	char	 blob[41];
81 	struct got_patch_hunk_head head;
82 };
83 
84 struct patch_args {
85 	got_patch_progress_cb progress_cb;
86 	void	*progress_arg;
87 	struct got_patch_hunk_head *head;
88 };
89 
90 static const struct got_error *
91 send_patch(struct imsgbuf *ibuf, int fd)
92 {
93 	const struct got_error *err = NULL;
94 
95 	if (imsg_compose(ibuf, GOT_IMSG_PATCH_FILE, 0, 0, fd,
96 	    NULL, 0) == -1) {
97 		err = got_error_from_errno(
98 		    "imsg_compose GOT_IMSG_PATCH_FILE");
99 		close(fd);
100 		return err;
101 	}
102 
103 	return got_privsep_flush_imsg(ibuf);
104 }
105 
106 static void
107 patch_free(struct got_patch *p)
108 {
109 	struct got_patch_hunk *h;
110 	size_t i;
111 
112 	while (!STAILQ_EMPTY(&p->head)) {
113 		h = STAILQ_FIRST(&p->head);
114 		STAILQ_REMOVE_HEAD(&p->head, entries);
115 
116 		for (i = 0; i < h->len; ++i)
117 			free(h->lines[i]);
118 		free(h->lines);
119 		free(h);
120 	}
121 
122 	free(p->new);
123 	free(p->old);
124 
125 	memset(p, 0, sizeof(*p));
126 	STAILQ_INIT(&p->head);
127 }
128 
129 static const struct got_error *
130 pushline(struct got_patch_hunk *h, const char *line)
131 {
132 	void 	*t;
133 	size_t	 newcap;
134 
135 	if (h->len == h->cap) {
136 		if ((newcap = h->cap * 1.5) == 0)
137 			newcap = 16;
138 		t = recallocarray(h->lines, h->cap, newcap,
139 		    sizeof(h->lines[0]));
140 		if (t == NULL)
141 			return got_error_from_errno("recallocarray");
142 		h->lines = t;
143 		h->cap = newcap;
144 	}
145 
146 	if ((t = strdup(line)) == NULL)
147 		return got_error_from_errno("strdup");
148 
149 	h->lines[h->len++] = t;
150 	return NULL;
151 }
152 
153 static const struct got_error *
154 recv_patch(struct imsgbuf *ibuf, int *done, struct got_patch *p, int strip)
155 {
156 	const struct got_error *err = NULL;
157 	struct imsg imsg;
158 	struct got_imsg_patch_hunk hdr;
159 	struct got_imsg_patch patch;
160 	struct got_patch_hunk *h = NULL;
161 	size_t datalen;
162 	int lastmode = -1;
163 
164 	memset(p, 0, sizeof(*p));
165 	STAILQ_INIT(&p->head);
166 
167 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
168 	if (err)
169 		return err;
170 	if (imsg.hdr.type == GOT_IMSG_PATCH_EOF) {
171 		*done = 1;
172 		goto done;
173 	}
174 	if (imsg.hdr.type != GOT_IMSG_PATCH) {
175 		err = got_error(GOT_ERR_PRIVSEP_MSG);
176 		goto done;
177 	}
178 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
179 	if (datalen != sizeof(patch)) {
180 		err = got_error(GOT_ERR_PRIVSEP_LEN);
181 		goto done;
182 	}
183 	memcpy(&patch, imsg.data, sizeof(patch));
184 
185 	if (patch.old[sizeof(patch.old)-1] != '\0' ||
186 	    patch.new[sizeof(patch.new)-1] != '\0' ||
187 	    patch.cid[sizeof(patch.cid)-1] != '\0' ||
188 	    patch.blob[sizeof(patch.blob)-1] != '\0') {
189 		err = got_error(GOT_ERR_PRIVSEP_LEN);
190 		goto done;
191 	}
192 
193 	if (*patch.cid != '\0')
194 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
195 
196 	if (*patch.blob != '\0')
197 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
198 
199 	/* automatically set strip=1 for git-style diffs */
200 	if (strip == -1 && patch.git &&
201 	    (*patch.old == '\0' || !strncmp(patch.old, "a/", 2)) &&
202 	    (*patch.new == '\0' || !strncmp(patch.new, "b/", 2)))
203 		strip = 1;
204 
205 	/* prefer the new name if not /dev/null for not git-style diffs */
206 	if (!patch.git && *patch.new != '\0' && *patch.old != '\0') {
207 		err = got_path_strip(&p->old, patch.new, strip);
208 		if (err)
209 			goto done;
210 	} else if (*patch.old != '\0') {
211 		err = got_path_strip(&p->old, patch.old, strip);
212 		if (err)
213 			goto done;
214 	}
215 
216 	if (*patch.new != '\0') {
217 		err = got_path_strip(&p->new, patch.new, strip);
218 		if (err)
219 			goto done;
220 	}
221 
222 	if (p->old == NULL && p->new == NULL) {
223 		err = got_error(GOT_ERR_PATCH_MALFORMED);
224 		goto done;
225 	}
226 
227 	imsg_free(&imsg);
228 
229 	for (;;) {
230 		char *t;
231 
232 		err = got_privsep_recv_imsg(&imsg, ibuf, 0);
233 		if (err) {
234 			patch_free(p);
235 			return err;
236 		}
237 
238 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
239 		switch (imsg.hdr.type) {
240 		case GOT_IMSG_PATCH_DONE:
241 			if (h != NULL && h->len == 0)
242 				err = got_error(GOT_ERR_PATCH_MALFORMED);
243 			goto done;
244 		case GOT_IMSG_PATCH_HUNK:
245 			if (h != NULL &&
246 			    (h->len == 0 || h->old_nonl || h->new_nonl)) {
247 				err = got_error(GOT_ERR_PATCH_MALFORMED);
248 				goto done;
249 			}
250 			lastmode = -1;
251 			if (datalen != sizeof(hdr)) {
252 				err = got_error(GOT_ERR_PRIVSEP_LEN);
253 				goto done;
254 			}
255 			memcpy(&hdr, imsg.data, sizeof(hdr));
256 			if (hdr.oldfrom < 0 || hdr.newfrom < 0) {
257 				err = got_error(GOT_ERR_PRIVSEP_LEN);
258 				goto done;
259 			}
260 			if ((h = calloc(1, sizeof(*h))) == NULL) {
261 				err = got_error_from_errno("calloc");
262 				goto done;
263 			}
264 			h->old_from = hdr.oldfrom;
265 			h->old_lines = hdr.oldlines;
266 			h->new_from = hdr.newfrom;
267 			h->new_lines = hdr.newlines;
268 			STAILQ_INSERT_TAIL(&p->head, h, entries);
269 			break;
270 		case GOT_IMSG_PATCH_LINE:
271 			if (h == NULL) {
272 				err = got_error(GOT_ERR_PRIVSEP_MSG);
273 				goto done;
274 			}
275 			t = imsg.data;
276 			/* at least one char */
277 			if (datalen < 2 || t[datalen-1] != '\0') {
278 				err = got_error(GOT_ERR_PRIVSEP_MSG);
279 				goto done;
280 			}
281 			if (*t != ' ' && *t != '-' && *t != '+' &&
282 			    *t != '\\') {
283 				err = got_error(GOT_ERR_PRIVSEP_MSG);
284 				goto done;
285 			}
286 
287 			if (*t != '\\')
288 				err = pushline(h, t);
289 			else if (lastmode == '-')
290 				h->old_nonl = 1;
291 			else if (lastmode == '+')
292 				h->new_nonl = 1;
293 			else
294 				err = got_error(GOT_ERR_PATCH_MALFORMED);
295 
296 			if (err)
297 				goto done;
298 
299 			lastmode = *t;
300 			break;
301 		default:
302 			err = got_error(GOT_ERR_PRIVSEP_MSG);
303 			goto done;
304 		}
305 
306 		imsg_free(&imsg);
307 	}
308 
309 done:
310 	if (err)
311 		patch_free(p);
312 
313 	imsg_free(&imsg);
314 	return err;
315 }
316 
317 static void
318 reverse_patch(struct got_patch *p)
319 {
320 	struct got_patch_hunk *h;
321 	size_t i;
322 	int tmp;
323 
324 	STAILQ_FOREACH(h, &p->head, entries) {
325 		tmp = h->old_from;
326 		h->old_from = h->new_from;
327 		h->new_from = tmp;
328 
329 		tmp = h->old_lines;
330 		h->old_lines = h->new_lines;
331 		h->new_lines = tmp;
332 
333 		tmp = h->old_nonl;
334 		h->old_nonl = h->new_nonl;
335 		h->new_nonl = tmp;
336 
337 		for (i = 0; i < h->len; ++i) {
338 			if (*h->lines[i] == '+')
339 				*h->lines[i] = '-';
340 			else if (*h->lines[i] == '-')
341 				*h->lines[i] = '+';
342 		}
343 	}
344 }
345 
346 /*
347  * Copy data from orig starting at copypos until pos into tmp.
348  * If pos is -1, copy until EOF.
349  */
350 static const struct got_error *
351 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
352 {
353 	char buf[BUFSIZ];
354 	size_t len, r, w;
355 
356 	if (fseeko(orig, copypos, SEEK_SET) == -1)
357 		return got_error_from_errno("fseeko");
358 
359 	while (pos == -1 || copypos < pos) {
360 		len = sizeof(buf);
361 		if (pos > 0)
362 			len = MIN(len, (size_t)pos - copypos);
363 		r = fread(buf, 1, len, orig);
364 		if (r != len && ferror(orig))
365 			return got_error_from_errno("fread");
366 		w = fwrite(buf, 1, r, tmp);
367 		if (w != r)
368 			return got_error_from_errno("fwrite");
369 		copypos += len;
370 		if (r != len && feof(orig)) {
371 			if (pos == -1)
372 				return NULL;
373 			return got_error(GOT_ERR_HUNK_FAILED);
374 		}
375 	}
376 	return NULL;
377 }
378 
379 static const struct got_error *
380 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
381 {
382 	const struct got_error *err = NULL;
383 	char *line = NULL;
384 	char mode = *h->lines[0];
385 	size_t linesize = 0;
386 	ssize_t linelen;
387 	off_t match = -1;
388 	int match_lineno = -1;
389 
390 	for (;;) {
391 		linelen = getline(&line, &linesize, orig);
392 		if (linelen == -1) {
393 			if (ferror(orig))
394 				err = got_error_from_errno("getline");
395 			else if (match == -1)
396 				err = got_error(GOT_ERR_HUNK_FAILED);
397 			break;
398 		}
399 		if (line[linelen - 1] == '\n')
400 			line[linelen - 1] = '\0';
401 		(*lineno)++;
402 
403 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
404 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
405 		    (mode == '+' && *lineno == h->old_from)) {
406 			match = ftello(orig);
407 			if (match == -1) {
408 				err = got_error_from_errno("ftello");
409 				break;
410 			}
411 			match -= linelen;
412 			match_lineno = (*lineno)-1;
413 		}
414 
415 		if (*lineno >= h->old_from && match != -1)
416 			break;
417 	}
418 
419 	if (err == NULL) {
420 		*pos = match;
421 		*lineno = match_lineno;
422 		if (fseeko(orig, match, SEEK_SET) == -1)
423 			err = got_error_from_errno("fseeko");
424 	}
425 
426 	free(line);
427 	return err;
428 }
429 
430 static int
431 linecmp(const char *a, const char *b, int *mangled)
432 {
433 	int c;
434 
435 	*mangled = 0;
436 	c = strcmp(a, b);
437 	if (c == 0)
438 		return c;
439 
440 	*mangled = 1;
441 	for (;;) {
442 		while (*a == '\t' || *a == ' ' || *a == '\f')
443 			a++;
444 		while (*b == '\t' || *b == ' ' || *b == '\f')
445 			b++;
446 		if (*a == '\0' || *a != *b)
447 			break;
448 		a++, b++;
449 	}
450 
451 	return *a - *b;
452 }
453 
454 static const struct got_error *
455 test_hunk(FILE *orig, struct got_patch_hunk *h)
456 {
457 	const struct got_error *err = NULL;
458 	char *line = NULL;
459 	size_t linesize = 0, i = 0;
460 	ssize_t linelen;
461 	int mangled;
462 
463 	for (i = 0; i < h->len; ++i) {
464 		switch (*h->lines[i]) {
465 		case '+':
466 			continue;
467 		case ' ':
468 		case '-':
469 			linelen = getline(&line, &linesize, orig);
470 			if (linelen == -1) {
471 				if (ferror(orig))
472 					err = got_error_from_errno("getline");
473 				else
474 					err = got_error(
475 					    GOT_ERR_HUNK_FAILED);
476 				goto done;
477 			}
478 			if (line[linelen - 1] == '\n')
479 				line[linelen - 1] = '\0';
480 			if (linecmp(h->lines[i] + 1, line, &mangled)) {
481 				err = got_error(GOT_ERR_HUNK_FAILED);
482 				goto done;
483 			}
484 			if (mangled)
485 				h->ws_mangled = 1;
486 			break;
487 		}
488 	}
489 
490 done:
491 	free(line);
492 	return err;
493 }
494 
495 static const struct got_error *
496 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
497     off_t from)
498 {
499 	const struct got_error *err = NULL;
500 	const char *t;
501 	size_t linesize = 0, i, new = 0;
502 	char *line = NULL;
503 	char mode;
504 	ssize_t linelen;
505 
506 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
507 		return got_error_from_errno("fseeko");
508 
509 	for (i = 0; i < h->len; ++i) {
510 		switch (mode = *h->lines[i]) {
511 		case '-':
512 		case ' ':
513 			(*lineno)++;
514 			if (orig != NULL) {
515 				linelen = getline(&line, &linesize, orig);
516 				if (linelen == -1) {
517 					err = got_error_from_errno("getline");
518 					goto done;
519 				}
520 				if (line[linelen - 1] == '\n')
521 					line[linelen - 1] = '\0';
522 				t = line;
523 			} else
524 				t = h->lines[i] + 1;
525 			if (mode == '-')
526 				continue;
527 			if (fprintf(tmp, "%s\n", t) < 0) {
528 				err = got_error_from_errno("fprintf");
529 				goto done;
530 			}
531 			break;
532 		case '+':
533 			new++;
534 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0) {
535 				err = got_error_from_errno("fprintf");
536 				goto done;
537 			}
538 			if (new != h->new_lines || !h->new_nonl) {
539 				if (fprintf(tmp, "\n") < 0) {
540 					err = got_error_from_errno("fprintf");
541 					goto done;
542 				}
543 			}
544 			break;
545 		}
546 	}
547 
548 done:
549 	free(line);
550 	return err;
551 }
552 
553 static const struct got_error *
554 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
555 {
556 	const struct got_error *err = NULL;
557 	struct got_patch_hunk *h;
558 	struct stat sb;
559 	int lineno = 0;
560 	off_t copypos, pos;
561 	char *line = NULL;
562 	size_t linesize = 0;
563 	ssize_t linelen;
564 
565 	if (p->old == NULL) {				/* create */
566 		h = STAILQ_FIRST(&p->head);
567 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
568 			return got_error(GOT_ERR_PATCH_MALFORMED);
569 		return apply_hunk(orig, tmp, h, &lineno, 0);
570 	}
571 
572 	if (fstat(fileno(orig), &sb) == -1)
573 		return got_error_from_errno("fstat");
574 
575 	copypos = 0;
576 	STAILQ_FOREACH(h, &p->head, entries) {
577 	tryagain:
578 		err = locate_hunk(orig, h, &pos, &lineno);
579 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
580 			h->err = err;
581 		if (err != NULL)
582 			return err;
583 		err = copy(tmp, orig, copypos, pos);
584 		if (err != NULL)
585 			return err;
586 		copypos = pos;
587 
588 		err = test_hunk(orig, h);
589 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
590 			/*
591 			 * try to apply the hunk again starting the search
592 			 * after the previous partial match.
593 			 */
594 			if (fseeko(orig, pos, SEEK_SET) == -1)
595 				return got_error_from_errno("fseeko");
596 			linelen = getline(&line, &linesize, orig);
597 			if (linelen == -1)
598 				return got_error_from_errno("getline");
599 			lineno++;
600 			goto tryagain;
601 		}
602 		if (err != NULL)
603 			return err;
604 
605 		if (lineno + 1 != h->old_from)
606 			h->offset = lineno + 1 - h->old_from;
607 
608 		err = apply_hunk(orig, tmp, h, &lineno, pos);
609 		if (err != NULL)
610 			return err;
611 
612 		copypos = ftello(orig);
613 		if (copypos == -1)
614 			return got_error_from_errno("ftello");
615 	}
616 
617 	if (p->new == NULL && sb.st_size != copypos) {
618 		h = STAILQ_FIRST(&p->head);
619 		h->err = got_error(GOT_ERR_HUNK_FAILED);
620 		err = h->err;
621 	} else if (!feof(orig))
622 		err = copy(tmp, orig, copypos, -1);
623 
624 	return err;
625 }
626 
627 static const struct got_error *
628 report_progress(struct patch_args *pa, const char *old, const char *new,
629     unsigned char status, const struct got_error *orig_error)
630 {
631 	const struct got_error *err;
632 	struct got_patch_hunk *h;
633 
634 	err = pa->progress_cb(pa->progress_arg, old, new, status,
635 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
636 	if (err)
637 		return err;
638 
639 	STAILQ_FOREACH(h, pa->head, entries) {
640 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
641 			continue;
642 
643 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
644 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
645 		    h->offset, h->ws_mangled, h->err);
646 		if (err)
647 			return err;
648 	}
649 
650 	return NULL;
651 }
652 
653 static const struct got_error *
654 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
655     const char *path)
656 {
657 	return report_progress(arg, path, NULL, status, NULL);
658 }
659 
660 static const struct got_error *
661 patch_add(void *arg, unsigned char status, const char *path)
662 {
663 	return report_progress(arg, NULL, path, status, NULL);
664 }
665 
666 static const struct got_error *
667 open_blob(char **path, FILE **fp, const char *blobid,
668     struct got_repository *repo)
669 {
670 	const struct got_error *err = NULL;
671 	struct got_blob_object *blob = NULL;
672 	struct got_object_id id, *idptr, *matched_id = NULL;
673 	int fd = -1;
674 
675 	*fp = NULL;
676 	*path = NULL;
677 
678 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
679 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
680 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
681 		    repo);
682 		if (err)
683 			return err;
684 		idptr = matched_id;
685 	} else {
686 		if (!got_parse_sha1_digest(id.sha1, blobid))
687 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
688 		idptr = &id;
689 	}
690 
691 	fd = got_opentempfd();
692 	if (fd == -1) {
693 		err = got_error_from_errno("got_opentempfd");
694 		goto done;
695 	}
696 
697 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
698 	if (err)
699 		goto done;
700 
701 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
702 	if (err)
703 		goto done;
704 
705 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
706 	if (err)
707 		goto done;
708 
709 done:
710 	if (fd != -1 && close(fd) == -1 && err == NULL)
711 		err = got_error_from_errno("close");
712 	if (blob)
713 		got_object_blob_close(blob);
714 	if (matched_id != NULL)
715 		free(matched_id);
716 	if (err) {
717 		if (*fp != NULL)
718 			fclose(*fp);
719 		if (*path != NULL)
720 			unlink(*path);
721 		free(*path);
722 		*fp = NULL;
723 		*path = NULL;
724 	}
725 	return err;
726 }
727 
728 static const struct got_error *
729 apply_patch(int *overlapcnt, struct got_worktree *worktree,
730     struct got_repository *repo, struct got_fileindex *fileindex,
731     const char *old, const char *new, struct got_patch *p, int nop,
732     int reverse, struct patch_args *pa,
733     got_cancel_cb cancel_cb, void *cancel_arg)
734 {
735 	const struct got_error *err = NULL;
736 	struct stat sb;
737 	int do_merge = 0, file_renamed = 0;
738 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
739 	char *oldpath = NULL, *newpath = NULL;
740 	char *tmppath = NULL, *template = NULL, *parent = NULL;
741 	char *apath = NULL, *mergepath = NULL;
742 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
743 	int outfd;
744 	const char *outpath;
745 	mode_t mode = GOT_DEFAULT_FILE_MODE;
746 
747 	*overlapcnt = 0;
748 
749 	/* don't run the diff3 merge on creations/deletions */
750 	if (*p->blob != '\0' && p->old != NULL && p->new != NULL) {
751 		err = open_blob(&apath, &afile, p->blob, repo);
752 		/*
753 		 * ignore failures to open this blob, we might have
754 		 * parsed gibberish.
755 		 */
756 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
757 		    err->code != GOT_ERR_NO_OBJ)
758 			return err;
759 		else if (err == NULL)
760 			do_merge = 1;
761 		else if (reverse)
762 			reverse_patch(p);
763 		err = NULL;
764 	}
765 
766 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
767 	    old) == -1) {
768 		err = got_error_from_errno("asprintf");
769 		goto done;
770 	}
771 
772 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
773 	    new) == -1) {
774 		err = got_error_from_errno("asprintf");
775 		goto done;
776 	}
777 
778 	file_renamed = strcmp(oldpath, newpath);
779 
780 	if (asprintf(&template, "%s/got-patch",
781 	    got_worktree_get_root_path(worktree)) == -1) {
782 		err = got_error_from_errno(template);
783 		goto done;
784 	}
785 
786 	if (p->old != NULL) {
787 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
788 			err = got_error_from_errno2("open", oldpath);
789 			goto done;
790 		}
791 		if (fstat(fileno(oldfile), &sb) == -1) {
792 			err = got_error_from_errno2("fstat", oldpath);
793 			goto done;
794 		}
795 		mode = sb.st_mode;
796 	}
797 
798 	err = got_opentemp_named(&tmppath, &tmpfile, template);
799 	if (err)
800 		goto done;
801 	outpath = tmppath;
802 	outfd = fileno(tmpfile);
803 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
804 	if (err)
805 		goto done;
806 
807 	if (do_merge) {
808 		const char *type, *id;
809 
810 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
811 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
812 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
813 			err = got_error_from_errno("fseeko");
814 			goto done;
815 		}
816 
817 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
818 			err = got_error_from_errno("asprintf");
819 			oldlabel = NULL;
820 			goto done;
821 		}
822 
823 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
824 			err = got_error_from_errno("asprintf");
825 			newlabel = NULL;
826 			goto done;
827 		}
828 
829 		if (*p->cid != '\0') {
830 			type = "commit";
831 			id = p->cid;
832 		} else {
833 			type = "blob";
834 			id = p->blob;
835 		}
836 
837 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
838 			err = got_error_from_errno("asprintf");
839 			anclabel = NULL;
840 			goto done;
841 		}
842 
843 		if (reverse) {
844 			char *s;
845 			FILE *t;
846 
847 			s = anclabel;
848 			anclabel = newlabel;
849 			newlabel = s;
850 
851 			t = afile;
852 			afile = tmpfile;
853 			tmpfile = t;
854 		}
855 
856 		err = got_opentemp_named(&mergepath, &mergefile, template);
857 		if (err)
858 			goto done;
859 		outpath = mergepath;
860 		outfd = fileno(mergefile);
861 
862 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
863 		    oldfile, oldlabel, anclabel, newlabel,
864 		    GOT_DIFF_ALGORITHM_PATIENCE);
865 		if (err)
866 			goto done;
867 	}
868 
869 	if (nop)
870 		goto done;
871 
872 	if (p->old != NULL && p->new == NULL) {
873 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
874 		    fileindex, patch_delete, pa);
875 		goto done;
876 	}
877 
878 	if (fchmod(outfd, mode) == -1) {
879 		err = got_error_from_errno2("chmod", tmppath);
880 		goto done;
881 	}
882 
883 	if (rename(outpath, newpath) == -1) {
884 		if (errno != ENOENT) {
885 			err = got_error_from_errno3("rename", outpath,
886 			    newpath);
887 			goto done;
888 		}
889 
890 		err = got_path_dirname(&parent, newpath);
891 		if (err != NULL)
892 			goto done;
893 		err = got_path_mkdir(parent);
894 		if (err != NULL)
895 			goto done;
896 		if (rename(outpath, newpath) == -1) {
897 			err = got_error_from_errno3("rename", outpath,
898 			    newpath);
899 			goto done;
900 		}
901 	}
902 
903 	if (file_renamed) {
904 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
905 		    fileindex, patch_delete, pa);
906 		if (err == NULL)
907 			err = got_worktree_patch_schedule_add(new, repo,
908 			    worktree, fileindex, patch_add,
909 			    pa);
910 		if (err)
911 			unlink(newpath);
912 	} else if (p->old == NULL) {
913 		err = got_worktree_patch_schedule_add(new, repo, worktree,
914 		    fileindex, patch_add, pa);
915 		if (err)
916 			unlink(newpath);
917 	} else if (*overlapcnt != 0)
918 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
919 	else if (do_merge)
920 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
921 	else
922 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
923 
924 done:
925 	free(parent);
926 	free(template);
927 
928 	if (tmppath != NULL)
929 		unlink(tmppath);
930 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
931 		err = got_error_from_errno("fclose");
932 	free(tmppath);
933 
934 	free(oldpath);
935 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
936 		err = got_error_from_errno("fclose");
937 
938 	if (apath != NULL)
939 		unlink(apath);
940 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
941 		err = got_error_from_errno("fclose");
942 	free(apath);
943 
944 	if (mergepath != NULL)
945 		unlink(mergepath);
946 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
947 		err = got_error_from_errno("fclose");
948 	free(mergepath);
949 
950 	free(newpath);
951 	free(oldlabel);
952 	free(newlabel);
953 	free(anclabel);
954 	return err;
955 }
956 
957 const struct got_error *
958 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
959     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
960     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
961 {
962 	const struct got_error *err = NULL, *complete_err = NULL;
963 	struct got_fileindex *fileindex = NULL;
964 	char *fileindex_path = NULL;
965 	char *oldpath, *newpath;
966 	struct imsgbuf *ibuf;
967 	int imsg_fds[2] = {-1, -1};
968 	int overlapcnt, done = 0, failed = 0;
969 	pid_t pid;
970 
971 	ibuf = calloc(1, sizeof(*ibuf));
972 	if (ibuf == NULL) {
973 		err = got_error_from_errno("calloc");
974 		goto done;
975 	}
976 
977 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
978 		err = got_error_from_errno("socketpair");
979 		goto done;
980 	}
981 
982 	pid = fork();
983 	if (pid == -1) {
984 		err = got_error_from_errno("fork");
985 		goto done;
986 	} else if (pid == 0) {
987 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
988 		    NULL);
989 		/* not reached */
990 	}
991 
992 	if (close(imsg_fds[1]) == -1) {
993 		err = got_error_from_errno("close");
994 		goto done;
995 	}
996 	imsg_fds[1] = -1;
997 	imsg_init(ibuf, imsg_fds[0]);
998 
999 	err = send_patch(ibuf, fd);
1000 	fd = -1;
1001 	if (err)
1002 		goto done;
1003 
1004 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
1005 	    worktree);
1006 	if (err)
1007 		goto done;
1008 
1009 	while (!done && err == NULL) {
1010 		struct got_patch p;
1011 		struct patch_args pa;
1012 
1013 		pa.progress_cb = progress_cb;
1014 		pa.progress_arg = progress_arg;
1015 		pa.head = &p.head;
1016 
1017 		err = recv_patch(ibuf, &done, &p, strip);
1018 		if (err || done)
1019 			break;
1020 
1021 		/* reversal application with merge base is done differently */
1022 		if (reverse && *p.blob == '\0')
1023 			reverse_patch(&p);
1024 
1025 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1026 		    &newpath, worktree, repo, fileindex);
1027 		if (err == NULL)
1028 			err = apply_patch(&overlapcnt, worktree, repo,
1029 			    fileindex, oldpath, newpath, &p, nop, reverse,
1030 			    &pa, cancel_cb, cancel_arg);
1031 		if (err != NULL) {
1032 			failed = 1;
1033 			/* recoverable errors */
1034 			if (err->code == GOT_ERR_FILE_STATUS ||
1035 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1036 				err = report_progress(&pa, p.old, p.new,
1037 				    GOT_STATUS_CANNOT_UPDATE, err);
1038 			else if (err->code == GOT_ERR_HUNK_FAILED)
1039 				err = report_progress(&pa, p.old, p.new,
1040 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1041 		}
1042 		if (overlapcnt != 0)
1043 			failed = 1;
1044 
1045 		free(oldpath);
1046 		free(newpath);
1047 		patch_free(&p);
1048 
1049 		if (err)
1050 			break;
1051 	}
1052 
1053 done:
1054 	if (fileindex != NULL)
1055 		complete_err = got_worktree_patch_complete(fileindex,
1056 		    fileindex_path);
1057 	if (complete_err && err == NULL)
1058 		err = complete_err;
1059 	free(fileindex_path);
1060 	if (fd != -1 && close(fd) == -1 && err == NULL)
1061 		err = got_error_from_errno("close");
1062 	if (ibuf != NULL)
1063 		imsg_clear(ibuf);
1064 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1065 		err = got_error_from_errno("close");
1066 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1067 		err = got_error_from_errno("close");
1068 	if (err == NULL && failed)
1069 		err = got_error(GOT_ERR_PATCH_FAILED);
1070 	return err;
1071 }