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 /*
316  * Copy data from orig starting at copypos until pos into tmp.
317  * If pos is -1, copy until EOF.
318  */
319 static const struct got_error *
320 copy(FILE *tmp, FILE *orig, off_t copypos, off_t pos)
321 {
322 	char buf[BUFSIZ];
323 	size_t len, r, w;
324 
325 	if (fseeko(orig, copypos, SEEK_SET) == -1)
326 		return got_error_from_errno("fseeko");
327 
328 	while (pos == -1 || copypos < pos) {
329 		len = sizeof(buf);
330 		if (pos > 0)
331 			len = MIN(len, (size_t)pos - copypos);
332 		r = fread(buf, 1, len, orig);
333 		if (r != len && ferror(orig))
334 			return got_error_from_errno("fread");
335 		w = fwrite(buf, 1, r, tmp);
336 		if (w != r)
337 			return got_error_from_errno("fwrite");
338 		copypos += len;
339 		if (r != len && feof(orig)) {
340 			if (pos == -1)
341 				return NULL;
342 			return got_error(GOT_ERR_HUNK_FAILED);
343 		}
344 	}
345 	return NULL;
346 }
347 
348 static const struct got_error *
349 locate_hunk(FILE *orig, struct got_patch_hunk *h, off_t *pos, int *lineno)
350 {
351 	const struct got_error *err = NULL;
352 	char *line = NULL;
353 	char mode = *h->lines[0];
354 	size_t linesize = 0;
355 	ssize_t linelen;
356 	off_t match = -1;
357 	int match_lineno = -1;
358 
359 	for (;;) {
360 		linelen = getline(&line, &linesize, orig);
361 		if (linelen == -1) {
362 			if (ferror(orig))
363 				err = got_error_from_errno("getline");
364 			else if (match == -1)
365 				err = got_error(GOT_ERR_HUNK_FAILED);
366 			break;
367 		}
368 		if (line[linelen - 1] == '\n')
369 			line[linelen - 1] = '\0';
370 		(*lineno)++;
371 
372 		if ((mode == ' ' && !strcmp(h->lines[0] + 1, line)) ||
373 		    (mode == '-' && !strcmp(h->lines[0] + 1, line)) ||
374 		    (mode == '+' && *lineno == h->old_from)) {
375 			match = ftello(orig);
376 			if (match == -1) {
377 				err = got_error_from_errno("ftello");
378 				break;
379 			}
380 			match -= linelen;
381 			match_lineno = (*lineno)-1;
382 		}
383 
384 		if (*lineno >= h->old_from && match != -1)
385 			break;
386 	}
387 
388 	if (err == NULL) {
389 		*pos = match;
390 		*lineno = match_lineno;
391 		if (fseeko(orig, match, SEEK_SET) == -1)
392 			err = got_error_from_errno("fseeko");
393 	}
394 
395 	free(line);
396 	return err;
397 }
398 
399 static int
400 linecmp(const char *a, const char *b, int *mangled)
401 {
402 	int c;
403 
404 	*mangled = 0;
405 	c = strcmp(a, b);
406 	if (c == 0)
407 		return c;
408 
409 	*mangled = 1;
410 	for (;;) {
411 		while (*a == '\t' || *a == ' ' || *a == '\f')
412 			a++;
413 		while (*b == '\t' || *b == ' ' || *b == '\f')
414 			b++;
415 		if (*a == '\0' || *a != *b)
416 			break;
417 		a++, b++;
418 	}
419 
420 	return *a - *b;
421 }
422 
423 static const struct got_error *
424 test_hunk(FILE *orig, struct got_patch_hunk *h)
425 {
426 	const struct got_error *err = NULL;
427 	char *line = NULL;
428 	size_t linesize = 0, i = 0;
429 	ssize_t linelen;
430 	int mangled;
431 
432 	for (i = 0; i < h->len; ++i) {
433 		switch (*h->lines[i]) {
434 		case '+':
435 			continue;
436 		case ' ':
437 		case '-':
438 			linelen = getline(&line, &linesize, orig);
439 			if (linelen == -1) {
440 				if (ferror(orig))
441 					err = got_error_from_errno("getline");
442 				else
443 					err = got_error(
444 					    GOT_ERR_HUNK_FAILED);
445 				goto done;
446 			}
447 			if (line[linelen - 1] == '\n')
448 				line[linelen - 1] = '\0';
449 			if (linecmp(h->lines[i] + 1, line, &mangled)) {
450 				err = got_error(GOT_ERR_HUNK_FAILED);
451 				goto done;
452 			}
453 			if (mangled)
454 				h->ws_mangled = 1;
455 			break;
456 		}
457 	}
458 
459 done:
460 	free(line);
461 	return err;
462 }
463 
464 static const struct got_error *
465 apply_hunk(FILE *orig, FILE *tmp, struct got_patch_hunk *h, int *lineno,
466     off_t from)
467 {
468 	const struct got_error *err = NULL;
469 	const char *t;
470 	size_t linesize = 0, i, new = 0;
471 	char *line = NULL;
472 	char mode;
473 	ssize_t linelen;
474 
475 	if (orig != NULL && fseeko(orig, from, SEEK_SET) == -1)
476 		return got_error_from_errno("fseeko");
477 
478 	for (i = 0; i < h->len; ++i) {
479 		switch (mode = *h->lines[i]) {
480 		case '-':
481 		case ' ':
482 			(*lineno)++;
483 			if (orig != NULL) {
484 				linelen = getline(&line, &linesize, orig);
485 				if (linelen == -1) {
486 					err = got_error_from_errno("getline");
487 					goto done;
488 				}
489 				if (line[linelen - 1] == '\n')
490 					line[linelen - 1] = '\0';
491 				t = line;
492 			} else
493 				t = h->lines[i] + 1;
494 			if (mode == '-')
495 				continue;
496 			if (fprintf(tmp, "%s\n", t) < 0) {
497 				err = got_error_from_errno("fprintf");
498 				goto done;
499 			}
500 			break;
501 		case '+':
502 			new++;
503 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0) {
504 				err = got_error_from_errno("fprintf");
505 				goto done;
506 			}
507 			if (new != h->new_lines || !h->new_nonl) {
508 				if (fprintf(tmp, "\n") < 0) {
509 					err = got_error_from_errno("fprintf");
510 					goto done;
511 				}
512 			}
513 			break;
514 		}
515 	}
516 
517 done:
518 	free(line);
519 	return err;
520 }
521 
522 static const struct got_error *
523 patch_file(struct got_patch *p, FILE *orig, FILE *tmp)
524 {
525 	const struct got_error *err = NULL;
526 	struct got_patch_hunk *h;
527 	struct stat sb;
528 	int lineno = 0;
529 	off_t copypos, pos;
530 	char *line = NULL;
531 	size_t linesize = 0;
532 	ssize_t linelen;
533 
534 	if (p->old == NULL) {				/* create */
535 		h = STAILQ_FIRST(&p->head);
536 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
537 			return got_error(GOT_ERR_PATCH_MALFORMED);
538 		return apply_hunk(orig, tmp, h, &lineno, 0);
539 	}
540 
541 	if (fstat(fileno(orig), &sb) == -1)
542 		return got_error_from_errno("fstat");
543 
544 	copypos = 0;
545 	STAILQ_FOREACH(h, &p->head, entries) {
546 	tryagain:
547 		err = locate_hunk(orig, h, &pos, &lineno);
548 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
549 			h->err = err;
550 		if (err != NULL)
551 			return err;
552 		err = copy(tmp, orig, copypos, pos);
553 		if (err != NULL)
554 			return err;
555 		copypos = pos;
556 
557 		err = test_hunk(orig, h);
558 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
559 			/*
560 			 * try to apply the hunk again starting the search
561 			 * after the previous partial match.
562 			 */
563 			if (fseeko(orig, pos, SEEK_SET) == -1)
564 				return got_error_from_errno("fseeko");
565 			linelen = getline(&line, &linesize, orig);
566 			if (linelen == -1)
567 				return got_error_from_errno("getline");
568 			lineno++;
569 			goto tryagain;
570 		}
571 		if (err != NULL)
572 			return err;
573 
574 		if (lineno + 1 != h->old_from)
575 			h->offset = lineno + 1 - h->old_from;
576 
577 		err = apply_hunk(orig, tmp, h, &lineno, pos);
578 		if (err != NULL)
579 			return err;
580 
581 		copypos = ftello(orig);
582 		if (copypos == -1)
583 			return got_error_from_errno("ftello");
584 	}
585 
586 	if (p->new == NULL && sb.st_size != copypos) {
587 		h = STAILQ_FIRST(&p->head);
588 		h->err = got_error(GOT_ERR_HUNK_FAILED);
589 		err = h->err;
590 	} else if (!feof(orig))
591 		err = copy(tmp, orig, copypos, -1);
592 
593 	return err;
594 }
595 
596 static const struct got_error *
597 report_progress(struct patch_args *pa, const char *old, const char *new,
598     unsigned char status, const struct got_error *orig_error)
599 {
600 	const struct got_error *err;
601 	struct got_patch_hunk *h;
602 
603 	err = pa->progress_cb(pa->progress_arg, old, new, status,
604 	    orig_error, 0, 0, 0, 0, 0, 0, NULL);
605 	if (err)
606 		return err;
607 
608 	STAILQ_FOREACH(h, pa->head, entries) {
609 		if (h->offset == 0 && !h->ws_mangled && h->err == NULL)
610 			continue;
611 
612 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
613 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
614 		    h->offset, h->ws_mangled, h->err);
615 		if (err)
616 			return err;
617 	}
618 
619 	return NULL;
620 }
621 
622 static const struct got_error *
623 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
624     const char *path)
625 {
626 	return report_progress(arg, path, NULL, status, NULL);
627 }
628 
629 static const struct got_error *
630 patch_add(void *arg, unsigned char status, const char *path)
631 {
632 	return report_progress(arg, NULL, path, status, NULL);
633 }
634 
635 static const struct got_error *
636 open_blob(char **path, FILE **fp, const char *blobid,
637     struct got_repository *repo)
638 {
639 	const struct got_error *err = NULL;
640 	struct got_blob_object *blob = NULL;
641 	struct got_object_id id, *idptr, *matched_id = NULL;
642 	int fd = -1;
643 
644 	*fp = NULL;
645 	*path = NULL;
646 
647 	if (strlen(blobid) != SHA1_DIGEST_STRING_LENGTH - 1) {
648 		err = got_repo_match_object_id(&matched_id, NULL, blobid,
649 		    GOT_OBJ_TYPE_BLOB, NULL /* do not resolve tags */,
650 		    repo);
651 		if (err)
652 			return err;
653 		idptr = matched_id;
654 	} else {
655 		if (!got_parse_sha1_digest(id.sha1, blobid))
656 			return got_error(GOT_ERR_BAD_OBJ_ID_STR);
657 		idptr = &id;
658 	}
659 
660 	fd = got_opentempfd();
661 	if (fd == -1) {
662 		err = got_error_from_errno("got_opentempfd");
663 		goto done;
664 	}
665 
666 	err = got_object_open_as_blob(&blob, repo, idptr, 8192, fd);
667 	if (err)
668 		goto done;
669 
670 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
671 	if (err)
672 		goto done;
673 
674 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
675 	if (err)
676 		goto done;
677 
678 done:
679 	if (fd != -1 && close(fd) == -1 && err == NULL)
680 		err = got_error_from_errno("close");
681 	if (blob)
682 		got_object_blob_close(blob);
683 	if (matched_id != NULL)
684 		free(matched_id);
685 	if (err) {
686 		if (*fp != NULL)
687 			fclose(*fp);
688 		if (*path != NULL)
689 			unlink(*path);
690 		free(*path);
691 		*fp = NULL;
692 		*path = NULL;
693 	}
694 	return err;
695 }
696 
697 static const struct got_error *
698 apply_patch(int *overlapcnt, struct got_worktree *worktree,
699     struct got_repository *repo, struct got_fileindex *fileindex,
700     const char *old, const char *new, struct got_patch *p, int nop,
701     struct patch_args *pa, got_cancel_cb cancel_cb, void *cancel_arg)
702 {
703 	const struct got_error *err = NULL;
704 	struct stat sb;
705 	int do_merge = 0, file_renamed = 0;
706 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
707 	char *oldpath = NULL, *newpath = NULL;
708 	char *tmppath = NULL, *template = NULL, *parent = NULL;
709 	char *apath = NULL, *mergepath = NULL;
710 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
711 	int outfd;
712 	const char *outpath;
713 	mode_t mode = GOT_DEFAULT_FILE_MODE;
714 
715 	*overlapcnt = 0;
716 
717 	/* don't run the diff3 merge on creations/deletions */
718 	if (*p->blob != '\0' && p->old != NULL && p->new != NULL) {
719 		err = open_blob(&apath, &afile, p->blob, repo);
720 		/*
721 		 * ignore failures to open this blob, we might have
722 		 * parsed gibberish.
723 		 */
724 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT) &&
725 		    err->code != GOT_ERR_NO_OBJ)
726 			return err;
727 		else if (err == NULL)
728 			do_merge = 1;
729 		err = NULL;
730 	}
731 
732 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
733 	    old) == -1) {
734 		err = got_error_from_errno("asprintf");
735 		goto done;
736 	}
737 
738 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
739 	    new) == -1) {
740 		err = got_error_from_errno("asprintf");
741 		goto done;
742 	}
743 
744 	file_renamed = strcmp(oldpath, newpath);
745 
746 	if (asprintf(&template, "%s/got-patch",
747 	    got_worktree_get_root_path(worktree)) == -1) {
748 		err = got_error_from_errno(template);
749 		goto done;
750 	}
751 
752 	if (p->old != NULL) {
753 		if ((oldfile = fopen(oldpath, "r")) == NULL) {
754 			err = got_error_from_errno2("open", oldpath);
755 			goto done;
756 		}
757 		if (fstat(fileno(oldfile), &sb) == -1) {
758 			err = got_error_from_errno2("fstat", oldpath);
759 			goto done;
760 		}
761 		mode = sb.st_mode;
762 	}
763 
764 	err = got_opentemp_named(&tmppath, &tmpfile, template);
765 	if (err)
766 		goto done;
767 	outpath = tmppath;
768 	outfd = fileno(tmpfile);
769 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile);
770 	if (err)
771 		goto done;
772 
773 	if (do_merge) {
774 		const char *type, *id;
775 
776 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
777 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
778 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
779 			err = got_error_from_errno("fseeko");
780 			goto done;
781 		}
782 
783 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
784 			err = got_error_from_errno("asprintf");
785 			oldlabel = NULL;
786 			goto done;
787 		}
788 
789 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
790 			err = got_error_from_errno("asprintf");
791 			newlabel = NULL;
792 			goto done;
793 		}
794 
795 		if (*p->cid != '\0') {
796 			type = "commit";
797 			id = p->cid;
798 		} else {
799 			type = "blob";
800 			id = p->blob;
801 		}
802 
803 		if (asprintf(&anclabel, "%s %s", type, id) == -1) {
804 			err = got_error_from_errno("asprintf");
805 			anclabel = NULL;
806 			goto done;
807 		}
808 
809 		err = got_opentemp_named(&mergepath, &mergefile, template);
810 		if (err)
811 			goto done;
812 		outpath = mergepath;
813 		outfd = fileno(mergefile);
814 
815 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
816 		    oldfile, oldlabel, anclabel, newlabel,
817 		    GOT_DIFF_ALGORITHM_PATIENCE);
818 		if (err)
819 			goto done;
820 	}
821 
822 	if (nop)
823 		goto done;
824 
825 	if (p->old != NULL && p->new == NULL) {
826 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
827 		    fileindex, patch_delete, pa);
828 		goto done;
829 	}
830 
831 	if (fchmod(outfd, mode) == -1) {
832 		err = got_error_from_errno2("chmod", tmppath);
833 		goto done;
834 	}
835 
836 	if (rename(outpath, newpath) == -1) {
837 		if (errno != ENOENT) {
838 			err = got_error_from_errno3("rename", outpath,
839 			    newpath);
840 			goto done;
841 		}
842 
843 		err = got_path_dirname(&parent, newpath);
844 		if (err != NULL)
845 			goto done;
846 		err = got_path_mkdir(parent);
847 		if (err != NULL)
848 			goto done;
849 		if (rename(outpath, newpath) == -1) {
850 			err = got_error_from_errno3("rename", outpath,
851 			    newpath);
852 			goto done;
853 		}
854 	}
855 
856 	if (file_renamed) {
857 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
858 		    fileindex, patch_delete, pa);
859 		if (err == NULL)
860 			err = got_worktree_patch_schedule_add(new, repo,
861 			    worktree, fileindex, patch_add,
862 			    pa);
863 		if (err)
864 			unlink(newpath);
865 	} else if (p->old == NULL) {
866 		err = got_worktree_patch_schedule_add(new, repo, worktree,
867 		    fileindex, patch_add, pa);
868 		if (err)
869 			unlink(newpath);
870 	} else if (*overlapcnt != 0)
871 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
872 	else if (do_merge)
873 		err = report_progress(pa, old, new, GOT_STATUS_MERGE, NULL);
874 	else
875 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
876 
877 done:
878 	free(parent);
879 	free(template);
880 
881 	if (tmppath != NULL)
882 		unlink(tmppath);
883 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
884 		err = got_error_from_errno("fclose");
885 	free(tmppath);
886 
887 	free(oldpath);
888 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
889 		err = got_error_from_errno("fclose");
890 
891 	if (apath != NULL)
892 		unlink(apath);
893 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
894 		err = got_error_from_errno("fclose");
895 	free(apath);
896 
897 	if (mergepath != NULL)
898 		unlink(mergepath);
899 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
900 		err = got_error_from_errno("fclose");
901 	free(mergepath);
902 
903 	free(newpath);
904 	free(oldlabel);
905 	free(newlabel);
906 	free(anclabel);
907 	return err;
908 }
909 
910 static void
911 reverse_patch(struct got_patch *p)
912 {
913 	struct got_patch_hunk *h;
914 	size_t i;
915 	int tmp;
916 
917 	STAILQ_FOREACH(h, &p->head, entries) {
918 		tmp = h->old_from;
919 		h->old_from = h->new_from;
920 		h->new_from = tmp;
921 
922 		tmp = h->old_lines;
923 		h->old_lines = h->new_lines;
924 		h->new_lines = tmp;
925 
926 		tmp = h->old_nonl;
927 		h->old_nonl = h->new_nonl;
928 		h->new_nonl = tmp;
929 
930 		for (i = 0; i < h->len; ++i) {
931 			if (*h->lines[i] == '+')
932 				*h->lines[i] = '-';
933 			else if (*h->lines[i] == '-')
934 				*h->lines[i] = '+';
935 		}
936 	}
937 }
938 
939 const struct got_error *
940 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
941     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
942     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
943 {
944 	const struct got_error *err = NULL, *complete_err = NULL;
945 	struct got_fileindex *fileindex = NULL;
946 	char *fileindex_path = NULL;
947 	char *oldpath, *newpath;
948 	struct imsgbuf *ibuf;
949 	int imsg_fds[2] = {-1, -1};
950 	int overlapcnt, done = 0, failed = 0;
951 	pid_t pid;
952 
953 	ibuf = calloc(1, sizeof(*ibuf));
954 	if (ibuf == NULL) {
955 		err = got_error_from_errno("calloc");
956 		goto done;
957 	}
958 
959 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
960 		err = got_error_from_errno("socketpair");
961 		goto done;
962 	}
963 
964 	pid = fork();
965 	if (pid == -1) {
966 		err = got_error_from_errno("fork");
967 		goto done;
968 	} else if (pid == 0) {
969 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
970 		    NULL);
971 		/* not reached */
972 	}
973 
974 	if (close(imsg_fds[1]) == -1) {
975 		err = got_error_from_errno("close");
976 		goto done;
977 	}
978 	imsg_fds[1] = -1;
979 	imsg_init(ibuf, imsg_fds[0]);
980 
981 	err = send_patch(ibuf, fd);
982 	fd = -1;
983 	if (err)
984 		goto done;
985 
986 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
987 	    worktree);
988 	if (err)
989 		goto done;
990 
991 	while (!done && err == NULL) {
992 		struct got_patch p;
993 		struct patch_args pa;
994 
995 		pa.progress_cb = progress_cb;
996 		pa.progress_arg = progress_arg;
997 		pa.head = &p.head;
998 
999 		err = recv_patch(ibuf, &done, &p, strip);
1000 		if (err || done)
1001 			break;
1002 
1003 		if (reverse)
1004 			reverse_patch(&p);
1005 
1006 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
1007 		    &newpath, worktree, repo, fileindex);
1008 		if (err == NULL)
1009 			err = apply_patch(&overlapcnt, worktree, repo,
1010 			    fileindex, oldpath, newpath, &p, nop, &pa,
1011 			    cancel_cb, cancel_arg);
1012 		if (err != NULL) {
1013 			failed = 1;
1014 			/* recoverable errors */
1015 			if (err->code == GOT_ERR_FILE_STATUS ||
1016 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
1017 				err = report_progress(&pa, p.old, p.new,
1018 				    GOT_STATUS_CANNOT_UPDATE, err);
1019 			else if (err->code == GOT_ERR_HUNK_FAILED)
1020 				err = report_progress(&pa, p.old, p.new,
1021 				    GOT_STATUS_CANNOT_UPDATE, NULL);
1022 		}
1023 		if (overlapcnt != 0)
1024 			failed = 1;
1025 
1026 		free(oldpath);
1027 		free(newpath);
1028 		patch_free(&p);
1029 
1030 		if (err)
1031 			break;
1032 	}
1033 
1034 done:
1035 	if (fileindex != NULL)
1036 		complete_err = got_worktree_patch_complete(fileindex,
1037 		    fileindex_path);
1038 	if (complete_err && err == NULL)
1039 		err = complete_err;
1040 	free(fileindex_path);
1041 	if (fd != -1 && close(fd) == -1 && err == NULL)
1042 		err = got_error_from_errno("close");
1043 	if (ibuf != NULL)
1044 		imsg_clear(ibuf);
1045 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
1046 		err = got_error_from_errno("close");
1047 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
1048 		err = got_error_from_errno("close");
1049 	if (err == NULL && failed)
1050 		err = got_error(GOT_ERR_PATCH_FAILED);
1051 	return err;
1052 }