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