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' && *patch.blob != '\0') {
193 		strlcpy(p->cid, patch.cid, sizeof(p->cid));
194 		strlcpy(p->blob, patch.blob, sizeof(p->blob));
195 	}
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 const struct got_error *
400 test_hunk(FILE *orig, struct got_patch_hunk *h)
401 {
402 	const struct got_error *err = NULL;
403 	char *line = NULL;
404 	size_t linesize = 0, i = 0;
405 	ssize_t linelen;
406 
407 	for (i = 0; i < h->len; ++i) {
408 		switch (*h->lines[i]) {
409 		case '+':
410 			continue;
411 		case ' ':
412 		case '-':
413 			linelen = getline(&line, &linesize, orig);
414 			if (linelen == -1) {
415 				if (ferror(orig))
416 					err = got_error_from_errno("getline");
417 				else
418 					err = got_error(
419 					    GOT_ERR_HUNK_FAILED);
420 				goto done;
421 			}
422 			if (line[linelen - 1] == '\n')
423 				line[linelen - 1] = '\0';
424 			if (strcmp(h->lines[i] + 1, line)) {
425 				err = got_error(GOT_ERR_HUNK_FAILED);
426 				goto done;
427 			}
428 			break;
429 		}
430 	}
431 
432 done:
433 	free(line);
434 	return err;
435 }
436 
437 static const struct got_error *
438 apply_hunk(FILE *tmp, struct got_patch_hunk *h, int *lineno)
439 {
440 	size_t i, new = 0;
441 
442 	for (i = 0; i < h->len; ++i) {
443 		switch (*h->lines[i]) {
444 		case ' ':
445 			if (fprintf(tmp, "%s\n", h->lines[i] + 1) < 0)
446 				return got_error_from_errno("fprintf");
447 			/* fallthrough */
448 		case '-':
449 			(*lineno)++;
450 			break;
451 		case '+':
452 			new++;
453 			if (fprintf(tmp, "%s", h->lines[i] + 1) < 0)
454 				return got_error_from_errno("fprintf");
455 			if (new != h->new_lines || !h->new_nonl) {
456 				if (fprintf(tmp, "\n") < 0)
457 					return got_error_from_errno(
458 					    "fprintf");
459 			}
460 			break;
461 		}
462 	}
463 	return NULL;
464 }
465 
466 static const struct got_error *
467 patch_file(struct got_patch *p, FILE *orig, FILE *tmp, mode_t *mode)
468 {
469 	const struct got_error *err = NULL;
470 	struct got_patch_hunk *h;
471 	struct stat sb;
472 	int lineno = 0;
473 	off_t copypos, pos;
474 	char *line = NULL;
475 	size_t linesize = 0;
476 	ssize_t linelen;
477 
478 	if (p->old == NULL) {				/* create */
479 		h = STAILQ_FIRST(&p->head);
480 		if (h == NULL || STAILQ_NEXT(h, entries) != NULL)
481 			return got_error(GOT_ERR_PATCH_MALFORMED);
482 		return apply_hunk(tmp, h, &lineno);
483 	}
484 
485 	if (fstat(fileno(orig), &sb) == -1)
486 		return got_error_from_errno("fstat");
487 	*mode = sb.st_mode;
488 
489 	copypos = 0;
490 	STAILQ_FOREACH(h, &p->head, entries) {
491 	tryagain:
492 		err = locate_hunk(orig, h, &pos, &lineno);
493 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED)
494 			h->err = err;
495 		if (err != NULL)
496 			return err;
497 		err = copy(tmp, orig, copypos, pos);
498 		if (err != NULL)
499 			return err;
500 		copypos = pos;
501 
502 		err = test_hunk(orig, h);
503 		if (err != NULL && err->code == GOT_ERR_HUNK_FAILED) {
504 			/*
505 			 * try to apply the hunk again starting the search
506 			 * after the previous partial match.
507 			 */
508 			if (fseeko(orig, pos, SEEK_SET) == -1)
509 				return got_error_from_errno("fseeko");
510 			linelen = getline(&line, &linesize, orig);
511 			if (linelen == -1)
512 				return got_error_from_errno("getline");
513 			lineno++;
514 			goto tryagain;
515 		}
516 		if (err != NULL)
517 			return err;
518 
519 		if (lineno + 1 != h->old_from)
520 			h->offset = lineno + 1 - h->old_from;
521 
522 		err = apply_hunk(tmp, h, &lineno);
523 		if (err != NULL)
524 			return err;
525 
526 		copypos = ftello(orig);
527 		if (copypos == -1)
528 			return got_error_from_errno("ftello");
529 	}
530 
531 	if (p->new == NULL && sb.st_size != copypos) {
532 		h = STAILQ_FIRST(&p->head);
533 		h->err = got_error(GOT_ERR_HUNK_FAILED);
534 		err = h->err;
535 	} else if (!feof(orig))
536 		err = copy(tmp, orig, copypos, -1);
537 
538 	return err;
539 }
540 
541 static const struct got_error *
542 report_progress(struct patch_args *pa, const char *old, const char *new,
543     unsigned char status, const struct got_error *orig_error)
544 {
545 	const struct got_error *err;
546 	struct got_patch_hunk *h;
547 
548 	err = pa->progress_cb(pa->progress_arg, old, new, status,
549 	    orig_error, 0, 0, 0, 0, 0, NULL);
550 	if (err)
551 		return err;
552 
553 	STAILQ_FOREACH(h, pa->head, entries) {
554 		if (h->offset == 0 && h->err == NULL)
555 			continue;
556 
557 		err = pa->progress_cb(pa->progress_arg, old, new, 0, NULL,
558 		    h->old_from, h->old_lines, h->new_from, h->new_lines,
559 		    h->offset, h->err);
560 		if (err)
561 			return err;
562 	}
563 
564 	return NULL;
565 }
566 
567 static const struct got_error *
568 patch_delete(void *arg, unsigned char status, unsigned char staged_status,
569     const char *path)
570 {
571 	return report_progress(arg, path, NULL, status, NULL);
572 }
573 
574 static const struct got_error *
575 patch_add(void *arg, unsigned char status, const char *path)
576 {
577 	return report_progress(arg, NULL, path, status, NULL);
578 }
579 
580 static const struct got_error *
581 open_blob(char **path, FILE **fp, const char *blobid,
582     struct got_repository *repo)
583 {
584 	const struct got_error *err = NULL;
585 	struct got_blob_object *blob = NULL;
586 	struct got_object_id id;
587 
588 	*fp = NULL;
589 	*path = NULL;
590 
591 	if (!got_parse_sha1_digest(id.sha1, blobid))
592 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
593 
594 	err = got_object_open_as_blob(&blob, repo, &id, 8192);
595 	if (err)
596 		goto done;
597 
598 	err = got_opentemp_named(path, fp, GOT_TMPDIR_STR "/got-patch-blob");
599 	if (err)
600 		goto done;
601 
602 	err = got_object_blob_dump_to_file(NULL, NULL, NULL, *fp, blob);
603 	if (err)
604 		goto done;
605 
606 done:
607 	if (blob)
608 		got_object_blob_close(blob);
609 	if (err) {
610 		if (*fp != NULL)
611 			fclose(*fp);
612 		if (*path != NULL)
613 			unlink(*path);
614 		free(*path);
615 		*fp = NULL;
616 		*path = NULL;
617 	}
618 	return err;
619 }
620 
621 static const struct got_error *
622 apply_patch(int *overlapcnt, struct got_worktree *worktree,
623     struct got_repository *repo, struct got_fileindex *fileindex,
624     const char *old, const char *new, struct got_patch *p, int nop,
625     struct patch_args *pa, got_cancel_cb cancel_cb, void *cancel_arg)
626 {
627 	const struct got_error *err = NULL;
628 	int do_merge = 0, file_renamed = 0;
629 	char *oldlabel = NULL, *newlabel = NULL, *anclabel = NULL;
630 	char *oldpath = NULL, *newpath = NULL;
631 	char *tmppath = NULL, *template = NULL, *parent = NULL;
632 	char *apath = NULL, *mergepath = NULL;
633 	FILE *oldfile = NULL, *tmpfile = NULL, *afile = NULL, *mergefile = NULL;
634 	int outfd;
635 	const char *outpath;
636 	mode_t mode = GOT_DEFAULT_FILE_MODE;
637 
638 	*overlapcnt = 0;
639 
640 	/* don't run the diff3 merge on creations/deletions */
641 	if (*p->blob != '\0' && p->old != NULL && p->new != NULL) {
642 		err = open_blob(&apath, &afile, p->blob, repo);
643 		/*
644 		 * ignore failures to open this blob, we might have
645 		 * parsed gibberish.
646 		 */
647 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT))
648 			return err;
649 		else if (err == NULL)
650 			do_merge = 1;
651 		err = NULL;
652 	}
653 
654 	if (asprintf(&oldpath, "%s/%s", got_worktree_get_root_path(worktree),
655 	    old) == -1) {
656 		err = got_error_from_errno("asprintf");
657 		goto done;
658 	}
659 
660 	if (asprintf(&newpath, "%s/%s", got_worktree_get_root_path(worktree),
661 	    new) == -1) {
662 		err = got_error_from_errno("asprintf");
663 		goto done;
664 	}
665 
666 	file_renamed = strcmp(oldpath, newpath);
667 
668 	if (asprintf(&template, "%s/got-patch",
669 	    got_worktree_get_root_path(worktree)) == -1) {
670 		err = got_error_from_errno(template);
671 		goto done;
672 	}
673 
674 	if (p->old != NULL && (oldfile = fopen(oldpath, "r")) == NULL) {
675 		err = got_error_from_errno2("open", oldpath);
676 		goto done;
677 	}
678 
679 	err = got_opentemp_named(&tmppath, &tmpfile, template);
680 	if (err)
681 		goto done;
682 	outpath = tmppath;
683 	outfd = fileno(tmpfile);
684 	err = patch_file(p, afile != NULL ? afile : oldfile, tmpfile, &mode);
685 	if (err)
686 		goto done;
687 
688 	if (do_merge) {
689 		if (fseeko(afile, 0, SEEK_SET) == -1 ||
690 		    fseeko(oldfile, 0, SEEK_SET) == -1 ||
691 		    fseeko(tmpfile, 0, SEEK_SET) == -1) {
692 			err = got_error_from_errno("fseeko");
693 			goto done;
694 		}
695 
696 		if (asprintf(&oldlabel, "--- %s", p->old) == -1) {
697 			err = got_error_from_errno("asprintf");
698 			oldlabel = NULL;
699 			goto done;
700 		}
701 
702 		if (asprintf(&newlabel, "+++ %s", p->new) == -1) {
703 			err = got_error_from_errno("asprintf");
704 			newlabel = NULL;
705 			goto done;
706 		}
707 
708 		if (asprintf(&anclabel, "commit %s", p->cid) == -1) {
709 			err = got_error_from_errno("asprintf");
710 			anclabel = NULL;
711 			goto done;
712 		}
713 
714 		err = got_opentemp_named(&mergepath, &mergefile, template);
715 		if (err)
716 			goto done;
717 		outpath = mergepath;
718 		outfd = fileno(mergefile);
719 
720 		err = got_merge_diff3(overlapcnt, outfd, tmpfile, afile,
721 		    oldfile, oldlabel, anclabel, newlabel,
722 		    GOT_DIFF_ALGORITHM_PATIENCE);
723 		if (err)
724 			goto done;
725 	}
726 
727 	if (nop)
728 		goto done;
729 
730 	if (p->old != NULL && p->new == NULL) {
731 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
732 		    fileindex, patch_delete, pa);
733 		goto done;
734 	}
735 
736 	if (fchmod(outfd, mode) == -1) {
737 		err = got_error_from_errno2("chmod", tmppath);
738 		goto done;
739 	}
740 
741 	if (rename(outpath, newpath) == -1) {
742 		if (errno != ENOENT) {
743 			err = got_error_from_errno3("rename", outpath,
744 			    newpath);
745 			goto done;
746 		}
747 
748 		err = got_path_dirname(&parent, newpath);
749 		if (err != NULL)
750 			goto done;
751 		err = got_path_mkdir(parent);
752 		if (err != NULL)
753 			goto done;
754 		if (rename(outpath, newpath) == -1) {
755 			err = got_error_from_errno3("rename", outpath,
756 			    newpath);
757 			goto done;
758 		}
759 	}
760 
761 	if (file_renamed) {
762 		err = got_worktree_patch_schedule_rm(old, repo, worktree,
763 		    fileindex, patch_delete, pa);
764 		if (err == NULL)
765 			err = got_worktree_patch_schedule_add(new, repo,
766 			    worktree, fileindex, patch_add,
767 			    pa);
768 		if (err)
769 			unlink(newpath);
770 	} else if (p->old == NULL) {
771 		err = got_worktree_patch_schedule_add(new, repo, worktree,
772 		    fileindex, patch_add, pa);
773 		if (err)
774 			unlink(newpath);
775 	} else if (*overlapcnt != 0)
776 		err = report_progress(pa, old, new, GOT_STATUS_CONFLICT, NULL);
777 	else
778 		err = report_progress(pa, old, new, GOT_STATUS_MODIFY, NULL);
779 
780 done:
781 	free(parent);
782 	free(template);
783 
784 	if (tmppath != NULL)
785 		unlink(tmppath);
786 	if (tmpfile != NULL && fclose(tmpfile) == EOF && err == NULL)
787 		err = got_error_from_errno("fclose");
788 	free(tmppath);
789 
790 	free(oldpath);
791 	if (oldfile != NULL && fclose(oldfile) == EOF && err == NULL)
792 		err = got_error_from_errno("fclose");
793 
794 	if (apath != NULL)
795 		unlink(apath);
796 	if (afile != NULL && fclose(afile) == EOF && err == NULL)
797 		err = got_error_from_errno("fclose");
798 	free(apath);
799 
800 	if (mergepath != NULL)
801 		unlink(mergepath);
802 	if (mergefile != NULL && fclose(mergefile) == EOF && err == NULL)
803 		err = got_error_from_errno("fclose");
804 	free(mergepath);
805 
806 	free(newpath);
807 	free(oldlabel);
808 	free(newlabel);
809 	free(anclabel);
810 	return err;
811 }
812 
813 static void
814 reverse_patch(struct got_patch *p)
815 {
816 	struct got_patch_hunk *h;
817 	size_t i;
818 	int tmp;
819 
820 	STAILQ_FOREACH(h, &p->head, entries) {
821 		tmp = h->old_from;
822 		h->old_from = h->new_from;
823 		h->new_from = tmp;
824 
825 		tmp = h->old_lines;
826 		h->old_lines = h->new_lines;
827 		h->new_lines = tmp;
828 
829 		tmp = h->old_nonl;
830 		h->old_nonl = h->new_nonl;
831 		h->new_nonl = tmp;
832 
833 		for (i = 0; i < h->len; ++i) {
834 			if (*h->lines[i] == '+')
835 				*h->lines[i] = '-';
836 			else if (*h->lines[i] == '-')
837 				*h->lines[i] = '+';
838 		}
839 	}
840 }
841 
842 const struct got_error *
843 got_patch(int fd, struct got_worktree *worktree, struct got_repository *repo,
844     int nop, int strip, int reverse, got_patch_progress_cb progress_cb,
845     void *progress_arg, got_cancel_cb cancel_cb, void *cancel_arg)
846 {
847 	const struct got_error *err = NULL, *complete_err = NULL;
848 	struct got_fileindex *fileindex = NULL;
849 	char *fileindex_path = NULL;
850 	char *oldpath, *newpath;
851 	struct imsgbuf *ibuf;
852 	int imsg_fds[2] = {-1, -1};
853 	int overlapcnt, done = 0, failed = 0;
854 	pid_t pid;
855 
856 	ibuf = calloc(1, sizeof(*ibuf));
857 	if (ibuf == NULL) {
858 		err = got_error_from_errno("calloc");
859 		goto done;
860 	}
861 
862 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
863 		err = got_error_from_errno("socketpair");
864 		goto done;
865 	}
866 
867 	pid = fork();
868 	if (pid == -1) {
869 		err = got_error_from_errno("fork");
870 		goto done;
871 	} else if (pid == 0) {
872 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PATCH,
873 		    NULL);
874 		/* not reached */
875 	}
876 
877 	if (close(imsg_fds[1]) == -1) {
878 		err = got_error_from_errno("close");
879 		goto done;
880 	}
881 	imsg_fds[1] = -1;
882 	imsg_init(ibuf, imsg_fds[0]);
883 
884 	err = send_patch(ibuf, fd);
885 	fd = -1;
886 	if (err)
887 		goto done;
888 
889 	err = got_worktree_patch_prepare(&fileindex, &fileindex_path,
890 	    worktree);
891 	if (err)
892 		goto done;
893 
894 	while (!done && err == NULL) {
895 		struct got_patch p;
896 		struct patch_args pa;
897 
898 		pa.progress_cb = progress_cb;
899 		pa.progress_arg = progress_arg;
900 		pa.head = &p.head;
901 
902 		err = recv_patch(ibuf, &done, &p, strip);
903 		if (err || done)
904 			break;
905 
906 		if (reverse)
907 			reverse_patch(&p);
908 
909 		err = got_worktree_patch_check_path(p.old, p.new, &oldpath,
910 		    &newpath, worktree, repo, fileindex);
911 		if (err == NULL)
912 			err = apply_patch(&overlapcnt, worktree, repo,
913 			    fileindex, oldpath, newpath, &p, nop, &pa,
914 			    cancel_cb, cancel_arg);
915 		if (err != NULL) {
916 			failed = 1;
917 			/* recoverable errors */
918 			if (err->code == GOT_ERR_FILE_STATUS ||
919 			    (err->code == GOT_ERR_ERRNO && errno == ENOENT))
920 				err = report_progress(&pa, p.old, p.new,
921 				    GOT_STATUS_CANNOT_UPDATE, err);
922 			else if (err->code == GOT_ERR_HUNK_FAILED)
923 				err = report_progress(&pa, p.old, p.new,
924 				    GOT_STATUS_CANNOT_UPDATE, NULL);
925 		}
926 		if (overlapcnt != 0)
927 			failed = 1;
928 
929 		free(oldpath);
930 		free(newpath);
931 		patch_free(&p);
932 
933 		if (err)
934 			break;
935 	}
936 
937 done:
938 	if (fileindex != NULL)
939 		complete_err = got_worktree_patch_complete(fileindex,
940 		    fileindex_path);
941 	if (complete_err && err == NULL)
942 		err = complete_err;
943 	free(fileindex_path);
944 	if (fd != -1 && close(fd) == -1 && err == NULL)
945 		err = got_error_from_errno("close");
946 	if (ibuf != NULL)
947 		imsg_clear(ibuf);
948 	if (imsg_fds[0] != -1 && close(imsg_fds[0]) == -1 && err == NULL)
949 		err = got_error_from_errno("close");
950 	if (imsg_fds[1] != -1 && close(imsg_fds[1]) == -1 && err == NULL)
951 		err = got_error_from_errno("close");
952 	if (err == NULL && failed)
953 		err = got_error(GOT_ERR_PATCH_FAILED);
954 	return err;
955 }