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