1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@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 
17 #include <sys/stat.h>
18 #include <sys/limits.h>
19 #include <sys/queue.h>
20 #include <sys/tree.h>
21 
22 #include <dirent.h>
23 #include <stddef.h>
24 #include <string.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <fcntl.h>
28 #include <errno.h>
29 #include <unistd.h>
30 #include <sha1.h>
31 #include <zlib.h>
32 #include <fnmatch.h>
33 #include <libgen.h>
34 #include <uuid.h>
35 #include <util.h>
36 
37 #include "got_error.h"
38 #include "got_repository.h"
39 #include "got_reference.h"
40 #include "got_object.h"
41 #include "got_worktree.h"
42 #include "got_opentemp.h"
43 
44 #include "got_lib_worktree.h"
45 #include "got_lib_path.h"
46 #include "got_lib_sha1.h"
47 #include "got_lib_fileindex.h"
48 #include "got_lib_inflate.h"
49 #include "got_lib_delta.h"
50 #include "got_lib_object.h"
51 #include "got_lib_diff.h"
52 
53 #ifndef MIN
54 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
55 #endif
56 
57 static const struct got_error *
58 create_meta_file(const char *path_got, const char *name, const char *content)
59 {
60 	const struct got_error *err = NULL;
61 	char *path;
62 	int fd = -1;
63 
64 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
65 		err = got_error_from_errno();
66 		path = NULL;
67 		goto done;
68 	}
69 
70 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
71 	    GOT_DEFAULT_FILE_MODE);
72 	if (fd == -1) {
73 		err = got_error_from_errno();
74 		goto done;
75 	}
76 
77 	if (content) {
78 		int len = dprintf(fd, "%s\n", content);
79 		if (len != strlen(content) + 1) {
80 			err = got_error_from_errno();
81 			goto done;
82 		}
83 	}
84 
85 done:
86 	if (fd != -1 && close(fd) == -1 && err == NULL)
87 		err = got_error_from_errno();
88 	free(path);
89 	return err;
90 }
91 
92 static const struct got_error *
93 update_meta_file(const char *path_got, const char *name, const char *content)
94 {
95 	const struct got_error *err = NULL;
96 	FILE *tmpfile = NULL;
97 	char *tmppath = NULL;
98 	char *path = NULL;
99 
100 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
101 		err = got_error_from_errno();
102 		path = NULL;
103 		goto done;
104 	}
105 
106 	err = got_opentemp_named(&tmppath, &tmpfile, path);
107 	if (err)
108 		goto done;
109 
110 	if (content) {
111 		int len = fprintf(tmpfile, "%s\n", content);
112 		if (len != strlen(content) + 1) {
113 			err = got_error_from_errno();
114 			goto done;
115 		}
116 	}
117 
118 	if (rename(tmppath, path) != 0) {
119 		err = got_error_from_errno();
120 		unlink(tmppath);
121 		goto done;
122 	}
123 
124 done:
125 	free(tmppath);
126 	if (fclose(tmpfile) != 0 && err == NULL)
127 		err = got_error_from_errno();
128 	return err;
129 }
130 
131 static const struct got_error *
132 read_meta_file(char **content, const char *path_got, const char *name)
133 {
134 	const struct got_error *err = NULL;
135 	char *path;
136 	int fd = -1;
137 	ssize_t n;
138 	struct stat sb;
139 
140 	*content = NULL;
141 
142 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
143 		err = got_error_from_errno();
144 		path = NULL;
145 		goto done;
146 	}
147 
148 	fd = open(path, O_RDONLY | O_NOFOLLOW);
149 	if (fd == -1) {
150 		if (errno == ENOENT)
151 			err = got_error(GOT_ERR_WORKTREE_META);
152 		else
153 			err = got_error_from_errno();
154 		goto done;
155 	}
156 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
157 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
158 		    : got_error_from_errno());
159 		goto done;
160 	}
161 
162 	if (lstat(path, &sb) != 0) {
163 		err = got_error_from_errno();
164 		goto done;
165 	}
166 	*content = calloc(1, sb.st_size);
167 	if (*content == NULL) {
168 		err = got_error_from_errno();
169 		goto done;
170 	}
171 
172 	n = read(fd, *content, sb.st_size);
173 	if (n != sb.st_size) {
174 		err = (n == -1 ? got_error_from_errno() :
175 		    got_error(GOT_ERR_WORKTREE_META));
176 		goto done;
177 	}
178 	if ((*content)[sb.st_size - 1] != '\n') {
179 		err = got_error(GOT_ERR_WORKTREE_META);
180 		goto done;
181 	}
182 	(*content)[sb.st_size - 1] = '\0';
183 
184 done:
185 	if (fd != -1 && close(fd) == -1 && err == NULL)
186 		err = got_error_from_errno();
187 	free(path);
188 	if (err) {
189 		free(*content);
190 		*content = NULL;
191 	}
192 	return err;
193 }
194 
195 const struct got_error *
196 got_worktree_init(const char *path, struct got_reference *head_ref,
197     const char *prefix, struct got_repository *repo)
198 {
199 	const struct got_error *err = NULL;
200 	struct got_object_id *commit_id = NULL;
201 	uuid_t uuid;
202 	uint32_t uuid_status;
203 	int obj_type;
204 	char *path_got = NULL;
205 	char *refstr = NULL;
206 	char *formatstr = NULL;
207 	char *absprefix = NULL;
208 	char *basestr = NULL;
209 	char *uuidstr = NULL;
210 
211 	if (strcmp(path, got_repo_get_path(repo)) == 0) {
212 		err = got_error(GOT_ERR_WORKTREE_REPO);
213 		goto done;
214 	}
215 
216 	err = got_ref_resolve(&commit_id, repo, head_ref);
217 	if (err)
218 		return err;
219 	err = got_object_get_type(&obj_type, repo, commit_id);
220 	if (err)
221 		return err;
222 	if (obj_type != GOT_OBJ_TYPE_COMMIT)
223 		return got_error(GOT_ERR_OBJ_TYPE);
224 
225 	if (!got_path_is_absolute(prefix)) {
226 		if (asprintf(&absprefix, "/%s", prefix) == -1)
227 			return got_error_from_errno();
228 	}
229 
230 	/* Create top-level directory (may already exist). */
231 	if (mkdir(path, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
232 		err = got_error_from_errno();
233 		goto done;
234 	}
235 
236 	/* Create .got directory (may already exist). */
237 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
238 		err = got_error_from_errno();
239 		goto done;
240 	}
241 	if (mkdir(path_got, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
242 		err = got_error_from_errno();
243 		goto done;
244 	}
245 
246 	/* Create an empty lock file. */
247 	err = create_meta_file(path_got, GOT_WORKTREE_LOCK, NULL);
248 	if (err)
249 		goto done;
250 
251 	/* Create an empty file index. */
252 	err = create_meta_file(path_got, GOT_WORKTREE_FILE_INDEX, NULL);
253 	if (err)
254 		goto done;
255 
256 	/* Write the HEAD reference. */
257 	refstr = got_ref_to_str(head_ref);
258 	if (refstr == NULL) {
259 		err = got_error_from_errno();
260 		goto done;
261 	}
262 	err = create_meta_file(path_got, GOT_WORKTREE_HEAD_REF, refstr);
263 	if (err)
264 		goto done;
265 
266 	/* Record our base commit. */
267 	err = got_object_id_str(&basestr, commit_id);
268 	if (err)
269 		goto done;
270 	err = create_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, basestr);
271 	if (err)
272 		goto done;
273 
274 	/* Store path to repository. */
275 	err = create_meta_file(path_got, GOT_WORKTREE_REPOSITORY,
276 	    got_repo_get_path(repo));
277 	if (err)
278 		goto done;
279 
280 	/* Store in-repository path prefix. */
281 	err = create_meta_file(path_got, GOT_WORKTREE_PATH_PREFIX,
282 	    absprefix ? absprefix : prefix);
283 	if (err)
284 		goto done;
285 
286 	/* Generate UUID. */
287 	uuid_create(&uuid, &uuid_status);
288 	if (uuid_status != uuid_s_ok) {
289 		err = got_error_uuid(uuid_status);
290 		goto done;
291 	}
292 	uuid_to_string(&uuid, &uuidstr, &uuid_status);
293 	if (uuid_status != uuid_s_ok) {
294 		err = got_error_uuid(uuid_status);
295 		goto done;
296 	}
297 	err = create_meta_file(path_got, GOT_WORKTREE_UUID, uuidstr);
298 	if (err)
299 		goto done;
300 
301 	/* Stamp work tree with format file. */
302 	if (asprintf(&formatstr, "%d", GOT_WORKTREE_FORMAT_VERSION) == -1) {
303 		err = got_error_from_errno();
304 		goto done;
305 	}
306 	err = create_meta_file(path_got, GOT_WORKTREE_FORMAT, formatstr);
307 	if (err)
308 		goto done;
309 
310 done:
311 	free(commit_id);
312 	free(path_got);
313 	free(formatstr);
314 	free(refstr);
315 	free(absprefix);
316 	free(basestr);
317 	free(uuidstr);
318 	return err;
319 }
320 
321 static const struct got_error *
322 open_worktree(struct got_worktree **worktree, const char *path)
323 {
324 	const struct got_error *err = NULL;
325 	char *path_got;
326 	char *formatstr = NULL;
327 	char *uuidstr = NULL;
328 	char *path_lock = NULL;
329 	char *base_commit_id_str = NULL;
330 	char *head_ref_str = NULL;
331 	int version, fd = -1;
332 	const char *errstr;
333 	struct got_repository *repo = NULL;
334 	uint32_t uuid_status;
335 
336 	*worktree = NULL;
337 
338 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
339 		err = got_error_from_errno();
340 		path_got = NULL;
341 		goto done;
342 	}
343 
344 	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
345 		err = got_error_from_errno();
346 		path_lock = NULL;
347 		goto done;
348 	}
349 
350 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK);
351 	if (fd == -1) {
352 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
353 		    : got_error_from_errno());
354 		goto done;
355 	}
356 
357 	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
358 	if (err)
359 		goto done;
360 
361 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
362 	if (errstr) {
363 		err = got_error(GOT_ERR_WORKTREE_META);
364 		goto done;
365 	}
366 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
367 		err = got_error(GOT_ERR_WORKTREE_VERS);
368 		goto done;
369 	}
370 
371 	*worktree = calloc(1, sizeof(**worktree));
372 	if (*worktree == NULL) {
373 		err = got_error_from_errno();
374 		goto done;
375 	}
376 	(*worktree)->lockfd = -1;
377 
378 	(*worktree)->root_path = strdup(path);
379 	if ((*worktree)->root_path == NULL) {
380 		err = got_error_from_errno();
381 		goto done;
382 	}
383 	err = read_meta_file(&(*worktree)->repo_path, path_got,
384 	    GOT_WORKTREE_REPOSITORY);
385 	if (err)
386 		goto done;
387 
388 	err = read_meta_file(&(*worktree)->path_prefix, path_got,
389 	    GOT_WORKTREE_PATH_PREFIX);
390 	if (err)
391 		goto done;
392 
393 	err = read_meta_file(&base_commit_id_str, path_got,
394 	    GOT_WORKTREE_BASE_COMMIT);
395 	if (err)
396 		goto done;
397 
398 	err = read_meta_file(&uuidstr, path_got, GOT_WORKTREE_UUID);
399 	if (err)
400 		goto done;
401 	uuid_from_string(uuidstr, &(*worktree)->uuid, &uuid_status);
402 	if (uuid_status != uuid_s_ok) {
403 		err = got_error_uuid(uuid_status);
404 		goto done;
405 	}
406 
407 	err = got_repo_open(&repo, (*worktree)->repo_path);
408 	if (err)
409 		goto done;
410 
411 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
412 	    base_commit_id_str);
413 	if (err)
414 		goto done;
415 
416 	err = read_meta_file(&head_ref_str, path_got, GOT_WORKTREE_HEAD_REF);
417 	if (err)
418 		goto done;
419 
420 	err = got_ref_open(&(*worktree)->head_ref, repo, head_ref_str);
421 done:
422 	if (repo)
423 		got_repo_close(repo);
424 	free(path_got);
425 	free(path_lock);
426 	free(head_ref_str);
427 	free(base_commit_id_str);
428 	free(uuidstr);
429 	free(formatstr);
430 	if (err) {
431 		if (fd != -1)
432 			close(fd);
433 		if (*worktree != NULL)
434 			got_worktree_close(*worktree);
435 		*worktree = NULL;
436 	} else
437 		(*worktree)->lockfd = fd;
438 
439 	return err;
440 }
441 
442 const struct got_error *
443 got_worktree_open(struct got_worktree **worktree, const char *path)
444 {
445 	const struct got_error *err = NULL;
446 
447 	do {
448 		err = open_worktree(worktree, path);
449 		if (err && !(err->code == GOT_ERR_ERRNO && errno == ENOENT))
450 			return err;
451 		if (*worktree)
452 			return NULL;
453 		path = dirname(path);
454 		if (path == NULL)
455 			return got_error_from_errno();
456 	} while (!((path[0] == '.' || path[0] == '/') && path[1] == '\0'));
457 
458 	return got_error(GOT_ERR_NOT_WORKTREE);
459 }
460 
461 const struct got_error *
462 got_worktree_close(struct got_worktree *worktree)
463 {
464 	const struct got_error *err = NULL;
465 	free(worktree->root_path);
466 	free(worktree->repo_path);
467 	free(worktree->path_prefix);
468 	free(worktree->base_commit_id);
469 	if (worktree->head_ref)
470 		got_ref_close(worktree->head_ref);
471 	if (worktree->lockfd != -1)
472 		if (close(worktree->lockfd) != 0)
473 			err = got_error_from_errno();
474 	free(worktree);
475 	return err;
476 }
477 
478 const char *
479 got_worktree_get_root_path(struct got_worktree *worktree)
480 {
481 	return worktree->root_path;
482 }
483 
484 const char *
485 got_worktree_get_repo_path(struct got_worktree *worktree)
486 {
487 	return worktree->repo_path;
488 }
489 
490 const char *
491 got_worktree_get_path_prefix(struct got_worktree *worktree)
492 {
493 	return worktree->path_prefix;
494 }
495 
496 const struct got_error *
497 got_worktree_match_path_prefix(int *match, struct got_worktree *worktree,
498     const char *path_prefix)
499 {
500 	char *absprefix = NULL;
501 
502 	if (!got_path_is_absolute(path_prefix)) {
503 		if (asprintf(&absprefix, "/%s", path_prefix) == -1)
504 			return got_error_from_errno();
505 	}
506 	*match = (strcmp(absprefix ? absprefix : path_prefix,
507 	    worktree->path_prefix) == 0);
508 	free(absprefix);
509 	return NULL;
510 }
511 
512 char *
513 got_worktree_get_head_ref_name(struct got_worktree *worktree)
514 {
515 	return got_ref_to_str(worktree->head_ref);
516 }
517 
518 struct got_reference *
519 got_worktree_get_head_ref(struct got_worktree *worktree)
520 {
521 	return got_ref_dup(worktree->head_ref);
522 }
523 
524 struct got_object_id *
525 got_worktree_get_base_commit_id(struct got_worktree *worktree)
526 {
527 	return worktree->base_commit_id;
528 }
529 
530 const struct got_error *
531 got_worktree_set_base_commit_id(struct got_worktree *worktree,
532     struct got_repository *repo, struct got_object_id *commit_id)
533 {
534 	const struct got_error *err;
535 	struct got_object *obj = NULL;
536 	char *id_str = NULL;
537 	char *path_got = NULL;
538 
539 	if (asprintf(&path_got, "%s/%s", worktree->root_path,
540 	    GOT_WORKTREE_GOT_DIR) == -1) {
541 		err = got_error_from_errno();
542 		path_got = NULL;
543 		goto done;
544 	}
545 
546 	err = got_object_open(&obj, repo, commit_id);
547 	if (err)
548 		return err;
549 
550 	if (obj->type != GOT_OBJ_TYPE_COMMIT) {
551 		err = got_error(GOT_ERR_OBJ_TYPE);
552 		goto done;
553 	}
554 
555 	/* Record our base commit. */
556 	err = got_object_id_str(&id_str, commit_id);
557 	if (err)
558 		goto done;
559 	err = update_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, id_str);
560 	if (err)
561 		goto done;
562 
563 	free(worktree->base_commit_id);
564 	worktree->base_commit_id = got_object_id_dup(commit_id);
565 	if (worktree->base_commit_id == NULL) {
566 		err = got_error_from_errno();
567 		goto done;
568 	}
569 done:
570 	if (obj)
571 		got_object_close(obj);
572 	free(id_str);
573 	free(path_got);
574 	return err;
575 }
576 
577 static const struct got_error *
578 lock_worktree(struct got_worktree *worktree, int operation)
579 {
580 	if (flock(worktree->lockfd, operation | LOCK_NB) == -1)
581 		return (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
582 		    : got_error_from_errno());
583 	return NULL;
584 }
585 
586 static const struct got_error *
587 add_dir_on_disk(struct got_worktree *worktree, const char *path)
588 {
589 	const struct got_error *err = NULL;
590 	char *abspath;
591 
592 	if (asprintf(&abspath, "%s/%s", worktree->root_path, path) == -1)
593 		return got_error_from_errno();
594 
595 	err = got_path_mkdir(abspath);
596 	if (err && err->code == GOT_ERR_ERRNO && errno == EEXIST) {
597 		struct stat sb;
598 		err = NULL;
599 		if (lstat(abspath, &sb) == -1) {
600 			err = got_error_from_errno();
601 		} else if (!S_ISDIR(sb.st_mode)) {
602 			/* TODO directory is obstructed; do something */
603 			err = got_error(GOT_ERR_FILE_OBSTRUCTED);
604 		}
605 	}
606 	free(abspath);
607 	return err;
608 }
609 
610 static const struct got_error *
611 check_file_contents_equal(int *same, FILE *f1, FILE *f2)
612 {
613 	const struct got_error *err = NULL;
614 	uint8_t fbuf1[8192];
615 	uint8_t fbuf2[8192];
616 	size_t flen1 = 0, flen2 = 0;
617 
618 	*same = 1;
619 
620 	while (1) {
621 		flen1 = fread(fbuf1, 1, sizeof(fbuf1), f1);
622 		if (flen1 == 0 && ferror(f1)) {
623 			err = got_error_from_errno();
624 			break;
625 		}
626 		flen2 = fread(fbuf2, 1, sizeof(fbuf2), f2);
627 		if (flen2 == 0 && ferror(f2)) {
628 			err = got_error_from_errno();
629 			break;
630 		}
631 		if (flen1 == 0) {
632 			if (flen2 != 0)
633 				*same = 0;
634 			break;
635 		} else if (flen2 == 0) {
636 			if (flen1 != 0)
637 				*same = 0;
638 			break;
639 		} else if (flen1 == flen2) {
640 			if (memcmp(fbuf1, fbuf2, flen2) != 0) {
641 				*same = 0;
642 				break;
643 			}
644 		} else {
645 			*same = 0;
646 			break;
647 		}
648 	}
649 
650 	return err;
651 }
652 
653 static const struct got_error *
654 check_files_equal(int *same, const char *f1_path, const char *f2_path)
655 {
656 	const struct got_error *err = NULL;
657 	struct stat sb;
658 	size_t size1, size2;
659 	FILE *f1 = NULL, *f2 = NULL;
660 
661 	*same = 1;
662 
663 	if (lstat(f1_path, &sb) != 0) {
664 		err = got_error_from_errno();
665 		goto done;
666 	}
667 	size1 = sb.st_size;
668 
669 	if (lstat(f2_path, &sb) != 0) {
670 		err = got_error_from_errno();
671 		goto done;
672 	}
673 	size2 = sb.st_size;
674 
675 	if (size1 != size2) {
676 		*same = 0;
677 		return NULL;
678 	}
679 
680 	f1 = fopen(f1_path, "r");
681 	if (f1 == NULL)
682 		return got_error_from_errno();
683 
684 	f2 = fopen(f2_path, "r");
685 	if (f2 == NULL) {
686 		err = got_error_from_errno();
687 		goto done;
688 	}
689 
690 	err = check_file_contents_equal(same, f1, f2);
691 done:
692 	if (f1 && fclose(f1) != 0 && err == NULL)
693 		err = got_error_from_errno();
694 	if (f2 && fclose(f2) != 0 && err == NULL)
695 		err = got_error_from_errno();
696 
697 	return err;
698 }
699 
700 /*
701  * Perform a 3-way merge where the file's version in the file index (blob2)
702  * acts as the common ancestor, the incoming blob (blob1) acts as the first
703  * derived version, and the file on disk acts as the second derived version.
704  */
705 static const struct got_error *
706 merge_blob(struct got_worktree *worktree, struct got_fileindex *fileindex,
707    struct got_fileindex_entry *ie, const char *ondisk_path, const char *path,
708    uint16_t te_mode, uint16_t st_mode, struct got_blob_object *blob1,
709    struct got_repository *repo,
710    got_worktree_checkout_cb progress_cb, void *progress_arg)
711 {
712 	const struct got_error *err = NULL;
713 	int merged_fd = -1;
714 	struct got_blob_object *blob2 = NULL;
715 	FILE *f1 = NULL, *f2 = NULL;
716 	char *blob1_path = NULL, *blob2_path = NULL;
717 	char *merged_path = NULL, *base_path = NULL;
718 	char *id_str = NULL;
719 	char *label1 = NULL;
720 	int overlapcnt = 0, update_timestamps = 0;
721 	char *parent;
722 
723 	parent = dirname(ondisk_path);
724 	if (parent == NULL)
725 		return got_error_from_errno();
726 
727 	if (asprintf(&base_path, "%s/got-merged", parent) == -1)
728 		return got_error_from_errno();
729 
730 	err = got_opentemp_named_fd(&merged_path, &merged_fd, base_path);
731 	if (err)
732 		goto done;
733 
734 	free(base_path);
735 	if (asprintf(&base_path, "%s/got-merge-blob1", parent) == -1) {
736 		err = got_error_from_errno();
737 		base_path = NULL;
738 		goto done;
739 	}
740 
741 	err = got_opentemp_named(&blob1_path, &f1, base_path);
742 	if (err)
743 		goto done;
744 	err = got_object_blob_dump_to_file(NULL, NULL, f1, blob1);
745 	if (err)
746 		goto done;
747 
748 	free(base_path);
749 	if (asprintf(&base_path, "%s/got-merge-blob2", parent) == -1) {
750 		err = got_error_from_errno();
751 		base_path = NULL;
752 		goto done;
753 	}
754 
755 	err = got_opentemp_named(&blob2_path, &f2, base_path);
756 	if (err)
757 		goto done;
758 	if (got_fileindex_entry_has_blob(ie)) {
759 		struct got_object_id id2;
760 		memcpy(id2.sha1, ie->blob_sha1, SHA1_DIGEST_LENGTH);
761 		err = got_object_open_as_blob(&blob2, repo, &id2, 8192);
762 		if (err)
763 			goto done;
764 		err = got_object_blob_dump_to_file(NULL, NULL, f2, blob2);
765 		if (err)
766 			goto done;
767 	} else {
768 		/*
769 		 * If the file has no blob, this is an "add vs add" conflict,
770 		 * and we simply use an empty ancestor file to make both files
771 		 * appear in the merged result in their entirety.
772 		 */
773 	}
774 
775 	err = got_object_id_str(&id_str, worktree->base_commit_id);
776 	if (err)
777 		goto done;
778 	if (asprintf(&label1, "commit %s", id_str) == -1) {
779 		err = got_error_from_errno();
780 		goto done;
781 	}
782 
783 	err = got_merge_diff3(&overlapcnt, merged_fd, blob1_path,
784 	    blob2_path, ondisk_path, label1, path);
785 	if (err)
786 		goto done;
787 
788 	(*progress_cb)(progress_arg,
789 	    overlapcnt > 0 ? GOT_STATUS_CONFLICT : GOT_STATUS_MERGE, path);
790 
791 
792 	if (fsync(merged_fd) != 0) {
793 		err = got_error_from_errno();
794 		goto done;
795 	}
796 
797 	/* Check if a clean merge has subsumed all local changes. */
798 	if (overlapcnt == 0) {
799 		err = check_files_equal(&update_timestamps, blob1_path,
800 		    merged_path);
801 		if (err)
802 			goto done;
803 	}
804 
805 	if (chmod(merged_path, st_mode) != 0) {
806 		err = got_error_from_errno();
807 		goto done;
808 	}
809 
810 	if (rename(merged_path, ondisk_path) != 0) {
811 		err = got_error_from_errno();
812 		unlink(merged_path);
813 		goto done;
814 	}
815 
816 	/*
817 	 * Do not update timestamps of already modified files. Otherwise,
818 	 * a future status walk would treat them as unmodified files again.
819 	 */
820 	err = got_fileindex_entry_update(ie, ondisk_path,
821 	    blob1->id.sha1, worktree->base_commit_id->sha1, update_timestamps);
822 done:
823 	if (merged_fd != -1 && close(merged_fd) != 0 && err == NULL)
824 		err = got_error_from_errno();
825 	if (f1 && fclose(f1) != 0 && err == NULL)
826 		err = got_error_from_errno();
827 	if (f2 && fclose(f2) != 0 && err == NULL)
828 		err = got_error_from_errno();
829 	if (blob2)
830 		got_object_blob_close(blob2);
831 	free(merged_path);
832 	free(base_path);
833 	if (blob1_path) {
834 		unlink(blob1_path);
835 		free(blob1_path);
836 	}
837 	if (blob2_path) {
838 		unlink(blob2_path);
839 		free(blob2_path);
840 	}
841 	free(id_str);
842 	free(label1);
843 	return err;
844 }
845 
846 static const struct got_error *
847 update_blob_fileindex_entry(struct got_worktree *worktree,
848     struct got_fileindex *fileindex, struct got_fileindex_entry *ie,
849     const char *ondisk_path, const char *path, struct got_blob_object *blob,
850     int update_timestamps)
851 {
852 	const struct got_error *err = NULL;
853 
854 	if (ie == NULL)
855 		ie = got_fileindex_entry_get(fileindex, path);
856 	if (ie)
857 		err = got_fileindex_entry_update(ie, ondisk_path,
858 		    blob->id.sha1, worktree->base_commit_id->sha1,
859 		    update_timestamps);
860 	else {
861 		struct got_fileindex_entry *new_ie;
862 		err = got_fileindex_entry_alloc(&new_ie, ondisk_path,
863 		    path, blob->id.sha1, worktree->base_commit_id->sha1);
864 		if (!err)
865 			err = got_fileindex_entry_add(fileindex, new_ie);
866 	}
867 	return err;
868 }
869 
870 static const struct got_error *
871 install_blob(struct got_worktree *worktree, const char *ondisk_path,
872    const char *path, uint16_t te_mode, uint16_t st_mode,
873    struct got_blob_object *blob, int restoring_missing_file,
874    struct got_repository *repo, got_worktree_checkout_cb progress_cb,
875    void *progress_arg)
876 {
877 	const struct got_error *err = NULL;
878 	int fd = -1;
879 	size_t len, hdrlen;
880 	int update = 0;
881 	char *tmppath = NULL;
882 
883 	fd = open(ondisk_path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
884 	    GOT_DEFAULT_FILE_MODE);
885 	if (fd == -1) {
886 		if (errno == ENOENT) {
887 			char *parent = dirname(path);
888 			if (parent == NULL)
889 				return got_error_from_errno();
890 			err = add_dir_on_disk(worktree, parent);
891 			if (err)
892 				return err;
893 			fd = open(ondisk_path,
894 			    O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
895 			    GOT_DEFAULT_FILE_MODE);
896 			if (fd == -1)
897 				return got_error_from_errno();
898 		} else if (errno == EEXIST) {
899 			if (!S_ISREG(st_mode)) {
900 				/* TODO file is obstructed; do something */
901 				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
902 				goto done;
903 			} else {
904 				err = got_opentemp_named_fd(&tmppath, &fd,
905 				    ondisk_path);
906 				if (err)
907 					goto done;
908 				update = 1;
909 			}
910 		} else
911 			return got_error_from_errno();
912 	}
913 
914 	if (restoring_missing_file)
915 		(*progress_cb)(progress_arg, GOT_STATUS_MISSING, path);
916 	else
917 		(*progress_cb)(progress_arg,
918 		    update ? GOT_STATUS_UPDATE : GOT_STATUS_ADD, path);
919 
920 	hdrlen = got_object_blob_get_hdrlen(blob);
921 	do {
922 		const uint8_t *buf = got_object_blob_get_read_buf(blob);
923 		err = got_object_blob_read_block(&len, blob);
924 		if (err)
925 			break;
926 		if (len > 0) {
927 			/* Skip blob object header first time around. */
928 			ssize_t outlen = write(fd, buf + hdrlen, len - hdrlen);
929 			if (outlen == -1) {
930 				err = got_error_from_errno();
931 				goto done;
932 			} else if (outlen != len - hdrlen) {
933 				err = got_error(GOT_ERR_IO);
934 				goto done;
935 			}
936 			hdrlen = 0;
937 		}
938 	} while (len != 0);
939 
940 	if (fsync(fd) != 0) {
941 		err = got_error_from_errno();
942 		goto done;
943 	}
944 
945 	if (update) {
946 		if (rename(tmppath, ondisk_path) != 0) {
947 			err = got_error_from_errno();
948 			unlink(tmppath);
949 			goto done;
950 		}
951 	}
952 
953 	if (te_mode & S_IXUSR) {
954 		if (chmod(ondisk_path, st_mode | S_IXUSR) == -1) {
955 			err = got_error_from_errno();
956 			goto done;
957 		}
958 	} else {
959 		if (chmod(ondisk_path, st_mode & ~S_IXUSR) == -1) {
960 			err = got_error_from_errno();
961 			goto done;
962 		}
963 	}
964 
965 done:
966 	if (fd != -1 && close(fd) != 0 && err == NULL)
967 		err = got_error_from_errno();
968 	free(tmppath);
969 	return err;
970 }
971 
972 /* Upgrade STATUS_MODIFY to STATUS_CONFLICT if a conflict marker is found. */
973 static const struct got_error *
974 get_modified_file_content_status(unsigned char *status, FILE *f)
975 {
976 	const struct got_error *err = NULL;
977 	const char *markers[3] = {
978 		GOT_DIFF_CONFLICT_MARKER_BEGIN,
979 		GOT_DIFF_CONFLICT_MARKER_SEP,
980 		GOT_DIFF_CONFLICT_MARKER_END
981 	};
982 	int i = 0;
983 	char *line;
984 	size_t len;
985 	const char delim[3] = {'\0', '\0', '\0'};
986 
987 	while (*status == GOT_STATUS_MODIFY) {
988 		line = fparseln(f, &len, NULL, delim, 0);
989 		if (line == NULL) {
990 			if (feof(f))
991 				break;
992 			err = got_ferror(f, GOT_ERR_IO);
993 			break;
994 		}
995 
996 		if (strncmp(line, markers[i], strlen(markers[i])) == 0) {
997 			if (markers[i] == GOT_DIFF_CONFLICT_MARKER_END)
998 				*status = GOT_STATUS_CONFLICT;
999 			else
1000 				i++;
1001 		}
1002 	}
1003 
1004 	return err;
1005 }
1006 
1007 static const struct got_error *
1008 get_file_status(unsigned char *status, struct stat *sb,
1009     struct got_fileindex_entry *ie, const char *abspath,
1010     struct got_repository *repo)
1011 {
1012 	const struct got_error *err = NULL;
1013 	struct got_object_id id;
1014 	size_t hdrlen;
1015 	FILE *f = NULL;
1016 	uint8_t fbuf[8192];
1017 	struct got_blob_object *blob = NULL;
1018 	size_t flen, blen;
1019 
1020 	*status = GOT_STATUS_NO_CHANGE;
1021 
1022 	if (lstat(abspath, sb) == -1) {
1023 		if (errno == ENOENT) {
1024 			if (ie) {
1025 				if (got_fileindex_entry_has_file_on_disk(ie))
1026 					*status = GOT_STATUS_MISSING;
1027 				else
1028 					*status = GOT_STATUS_DELETE;
1029 				sb->st_mode =
1030 				    ((ie->mode >> GOT_FILEIDX_MODE_PERMS_SHIFT)
1031 				    & (S_IRWXU | S_IRWXG | S_IRWXO));
1032 			} else
1033 				sb->st_mode = GOT_DEFAULT_FILE_MODE;
1034 			return NULL;
1035 		}
1036 		return got_error_from_errno();
1037 	}
1038 
1039 	if (!S_ISREG(sb->st_mode)) {
1040 		*status = GOT_STATUS_OBSTRUCTED;
1041 		return NULL;
1042 	}
1043 
1044 	if (ie == NULL)
1045 		return NULL;
1046 
1047 	if (!got_fileindex_entry_has_file_on_disk(ie)) {
1048 		*status = GOT_STATUS_DELETE;
1049 		return NULL;
1050 	} else if (!got_fileindex_entry_has_blob(ie)) {
1051 		*status = GOT_STATUS_ADD;
1052 		return NULL;
1053 	}
1054 
1055 	if (ie->ctime_sec == sb->st_ctime &&
1056 	    ie->ctime_nsec == sb->st_ctimensec &&
1057 	    ie->mtime_sec == sb->st_mtime &&
1058 	    ie->mtime_sec == sb->st_mtime &&
1059 	    ie->mtime_nsec == sb->st_mtimensec &&
1060 	    ie->size == (sb->st_size & 0xffffffff))
1061 		return NULL;
1062 
1063 	memcpy(id.sha1, ie->blob_sha1, sizeof(id.sha1));
1064 	err = got_object_open_as_blob(&blob, repo, &id, sizeof(fbuf));
1065 	if (err)
1066 		return err;
1067 
1068 	f = fopen(abspath, "r");
1069 	if (f == NULL) {
1070 		err = got_error_from_errno();
1071 		goto done;
1072 	}
1073 	hdrlen = got_object_blob_get_hdrlen(blob);
1074 	while (1) {
1075 		const uint8_t *bbuf = got_object_blob_get_read_buf(blob);
1076 		err = got_object_blob_read_block(&blen, blob);
1077 		if (err)
1078 			goto done;
1079 		/* Skip length of blob object header first time around. */
1080 		flen = fread(fbuf, 1, sizeof(fbuf) - hdrlen, f);
1081 		if (flen == 0 && ferror(f)) {
1082 			err = got_error_from_errno();
1083 			goto done;
1084 		}
1085 		if (blen == 0) {
1086 			if (flen != 0)
1087 				*status = GOT_STATUS_MODIFY;
1088 			break;
1089 		} else if (flen == 0) {
1090 			if (blen != 0)
1091 				*status = GOT_STATUS_MODIFY;
1092 			break;
1093 		} else if (blen - hdrlen == flen) {
1094 			/* Skip blob object header first time around. */
1095 			if (memcmp(bbuf + hdrlen, fbuf, flen) != 0) {
1096 				*status = GOT_STATUS_MODIFY;
1097 				break;
1098 			}
1099 		} else {
1100 			*status = GOT_STATUS_MODIFY;
1101 			break;
1102 		}
1103 		hdrlen = 0;
1104 	}
1105 
1106 	if (*status == GOT_STATUS_MODIFY) {
1107 		rewind(f);
1108 		err = get_modified_file_content_status(status, f);
1109 	}
1110 done:
1111 	if (blob)
1112 		got_object_blob_close(blob);
1113 	if (f)
1114 		fclose(f);
1115 	return err;
1116 }
1117 
1118 static const struct got_error *
1119 update_blob(struct got_worktree *worktree,
1120     struct got_fileindex *fileindex, struct got_fileindex_entry *ie,
1121     struct got_tree_entry *te, const char *path,
1122     struct got_repository *repo, got_worktree_checkout_cb progress_cb,
1123     void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
1124 {
1125 	const struct got_error *err = NULL;
1126 	struct got_blob_object *blob = NULL;
1127 	char *ondisk_path;
1128 	unsigned char status = GOT_STATUS_NO_CHANGE;
1129 	struct stat sb;
1130 
1131 	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path, path) == -1)
1132 		return got_error_from_errno();
1133 
1134 	err = get_file_status(&status, &sb, ie, ondisk_path, repo);
1135 	if (err)
1136 		goto done;
1137 
1138 	if (status == GOT_STATUS_OBSTRUCTED) {
1139 		(*progress_cb)(progress_arg, status, path);
1140 		goto done;
1141 	}
1142 
1143 	if (ie && status != GOT_STATUS_MISSING) {
1144 		if (got_fileindex_entry_has_commit(ie) &&
1145 		    memcmp(ie->commit_sha1, worktree->base_commit_id->sha1,
1146 		    SHA1_DIGEST_LENGTH) == 0) {
1147 			(*progress_cb)(progress_arg, GOT_STATUS_EXISTS,
1148 			    path);
1149 			goto done;
1150 		}
1151 		if (got_fileindex_entry_has_blob(ie) &&
1152 		    memcmp(ie->blob_sha1, te->id->sha1,
1153 		    SHA1_DIGEST_LENGTH) == 0)
1154 			goto done;
1155 	}
1156 
1157 	err = got_object_open_as_blob(&blob, repo, te->id, 8192);
1158 	if (err)
1159 		goto done;
1160 
1161 	if (status == GOT_STATUS_MODIFY || status == GOT_STATUS_ADD)
1162 		err = merge_blob(worktree, fileindex, ie, ondisk_path, path,
1163 		    te->mode, sb.st_mode, blob, repo, progress_cb,
1164 		    progress_arg);
1165 	else if (status == GOT_STATUS_DELETE) {
1166 		(*progress_cb)(progress_arg, GOT_STATUS_MERGE, path);
1167 		err = update_blob_fileindex_entry(worktree, fileindex, ie,
1168 		    ondisk_path, path, blob, 0);
1169 		if (err)
1170 			goto done;
1171 	} else {
1172 		err = install_blob(worktree, ondisk_path, path, te->mode,
1173 		    sb.st_mode, blob, status == GOT_STATUS_MISSING, repo,
1174 		    progress_cb, progress_arg);
1175 		if (err)
1176 			goto done;
1177 		err = update_blob_fileindex_entry(worktree, fileindex, ie,
1178 		    ondisk_path, path, blob, 1);
1179 		if (err)
1180 			goto done;
1181 	}
1182 	got_object_blob_close(blob);
1183 done:
1184 	free(ondisk_path);
1185 	return err;
1186 }
1187 
1188 static const struct got_error *
1189 remove_ondisk_file(const char *root_path, const char *path)
1190 {
1191 	const struct got_error *err = NULL;
1192 	char *ondisk_path = NULL;
1193 
1194 	if (asprintf(&ondisk_path, "%s/%s", root_path, path) == -1)
1195 		return got_error_from_errno();
1196 
1197 	if (unlink(ondisk_path) == -1) {
1198 		if (errno != ENOENT)
1199 			err = got_error_from_errno();
1200 	} else {
1201 		char *parent = dirname(ondisk_path);
1202 		while (parent && strcmp(parent, root_path) != 0) {
1203 			if (rmdir(parent) == -1) {
1204 				if (errno != ENOTEMPTY)
1205 					err = got_error_from_errno();
1206 				break;
1207 			}
1208 			parent = dirname(parent);
1209 		}
1210 	}
1211 	free(ondisk_path);
1212 	return err;
1213 }
1214 
1215 static const struct got_error *
1216 delete_blob(struct got_worktree *worktree, struct got_fileindex *fileindex,
1217     struct got_fileindex_entry *ie, const char *parent_path,
1218     struct got_repository *repo,
1219     got_worktree_checkout_cb progress_cb, void *progress_arg,
1220     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
1221 {
1222 	const struct got_error *err = NULL;
1223 	unsigned char status;
1224 	struct stat sb;
1225 	char *ondisk_path;
1226 
1227 	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path, ie->path)
1228 	    == -1)
1229 		return got_error_from_errno();
1230 
1231 	err = get_file_status(&status, &sb, ie, ondisk_path, repo);
1232 	if (err)
1233 		return err;
1234 
1235 	if (status == GOT_STATUS_MODIFY || status == GOT_STATUS_CONFLICT ||
1236 	    status == GOT_STATUS_ADD) {
1237 		(*progress_cb)(progress_arg, GOT_STATUS_MERGE, ie->path);
1238 		/*
1239 		 * Preserve the working file and change the deleted blob's
1240 		 * entry into a schedule-add entry.
1241 		 */
1242 		err = got_fileindex_entry_update(ie, ondisk_path, NULL, NULL,
1243 		    0);
1244 		if (err)
1245 			return err;
1246 	} else {
1247 		(*progress_cb)(progress_arg, GOT_STATUS_DELETE, ie->path);
1248 		if (status == GOT_STATUS_NO_CHANGE) {
1249 			err = remove_ondisk_file(worktree->root_path, ie->path);
1250 			if (err)
1251 				return err;
1252 		}
1253 		got_fileindex_entry_remove(fileindex, ie);
1254 	}
1255 
1256 	return err;
1257 }
1258 
1259 struct diff_cb_arg {
1260     struct got_fileindex *fileindex;
1261     struct got_worktree *worktree;
1262     struct got_repository *repo;
1263     got_worktree_checkout_cb progress_cb;
1264     void *progress_arg;
1265     got_worktree_cancel_cb cancel_cb;
1266     void *cancel_arg;
1267 };
1268 
1269 static const struct got_error *
1270 diff_old_new(void *arg, struct got_fileindex_entry *ie,
1271     struct got_tree_entry *te, const char *parent_path)
1272 {
1273 	struct diff_cb_arg *a = arg;
1274 
1275 	return update_blob(a->worktree, a->fileindex, ie, te,
1276 	    ie->path, a->repo, a->progress_cb, a->progress_arg,
1277 	    a->cancel_cb, a->cancel_arg);
1278 }
1279 
1280 static const struct got_error *
1281 diff_old(void *arg, struct got_fileindex_entry *ie, const char *parent_path)
1282 {
1283 	struct diff_cb_arg *a = arg;
1284 
1285 	return delete_blob(a->worktree, a->fileindex, ie, parent_path,
1286 	    a->repo, a->progress_cb, a->progress_arg,
1287 	    a->cancel_cb, a->cancel_arg);
1288 }
1289 
1290 static const struct got_error *
1291 diff_new(void *arg, struct got_tree_entry *te, const char *parent_path)
1292 {
1293 	struct diff_cb_arg *a = arg;
1294 	const struct got_error *err;
1295 	char *path;
1296 
1297 	if (asprintf(&path, "%s%s%s", parent_path,
1298 	    parent_path[0] ? "/" : "", te->name)
1299 	    == -1)
1300 		return got_error_from_errno();
1301 
1302 	if (S_ISDIR(te->mode))
1303 		err = add_dir_on_disk(a->worktree, path);
1304 	else
1305 		err = update_blob(a->worktree, a->fileindex, NULL, te, path,
1306 		    a->repo, a->progress_cb, a->progress_arg,
1307 		    a->cancel_cb, a->cancel_arg);
1308 
1309 	free(path);
1310 	return err;
1311 }
1312 
1313 const struct got_error *
1314 got_worktree_get_base_ref_name(char **refname, struct got_worktree *worktree)
1315 {
1316 	const struct got_error *err = NULL;
1317 	char *uuidstr = NULL;
1318 	uint32_t uuid_status;
1319 
1320 	*refname = NULL;
1321 
1322 	uuid_to_string(&worktree->uuid, &uuidstr, &uuid_status);
1323 	if (uuid_status != uuid_s_ok)
1324 		return got_error_uuid(uuid_status);
1325 
1326 	if (asprintf(refname, "%s-%s", GOT_WORKTREE_BASE_REF_PREFIX, uuidstr)
1327 	    == -1) {
1328 		err = got_error_from_errno();
1329 		*refname = NULL;
1330 	}
1331 	free(uuidstr);
1332 	return err;
1333 }
1334 
1335 /*
1336  * Prevent Git's garbage collector from deleting our base commit by
1337  * setting a reference to our base commit's ID.
1338  */
1339 static const struct got_error *
1340 ref_base_commit(struct got_worktree *worktree, struct got_repository *repo)
1341 {
1342 	const struct got_error *err = NULL;
1343 	struct got_reference *ref = NULL;
1344 	char *refname;
1345 
1346 	err = got_worktree_get_base_ref_name(&refname, worktree);
1347 	if (err)
1348 		return err;
1349 
1350 	err = got_ref_alloc(&ref, refname, worktree->base_commit_id);
1351 	if (err)
1352 		goto done;
1353 
1354 	err = got_ref_write(ref, repo);
1355 done:
1356 	free(refname);
1357 	if (ref)
1358 		got_ref_close(ref);
1359 	return err;
1360 }
1361 
1362 
1363 const struct got_error *
1364 got_worktree_checkout_files(struct got_worktree *worktree,
1365     struct got_repository *repo, got_worktree_checkout_cb progress_cb,
1366     void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
1367 {
1368 	const struct got_error *err = NULL, *unlockerr, *checkout_err = NULL;
1369 	struct got_commit_object *commit = NULL;
1370 	struct got_object_id *tree_id = NULL;
1371 	struct got_tree_object *tree = NULL;
1372 	char *fileindex_path = NULL, *new_fileindex_path = NULL;
1373 	struct got_fileindex *fileindex = NULL;
1374 	FILE *index = NULL, *new_index = NULL;
1375 	struct got_fileindex_diff_tree_cb diff_cb;
1376 	struct diff_cb_arg arg;
1377 
1378 	err = lock_worktree(worktree, LOCK_EX);
1379 	if (err)
1380 		return err;
1381 
1382 	fileindex = got_fileindex_alloc();
1383 	if (fileindex == NULL) {
1384 		err = got_error_from_errno();
1385 		goto done;
1386 	}
1387 
1388 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
1389 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
1390 		err = got_error_from_errno();
1391 		fileindex_path = NULL;
1392 		goto done;
1393 	}
1394 
1395 	/*
1396 	 * Read the file index.
1397 	 * Checking out files is supposed to be an idempotent operation.
1398 	 * If the on-disk file index is incomplete we will try to complete it.
1399 	 */
1400 	index = fopen(fileindex_path, "rb");
1401 	if (index == NULL) {
1402 		if (errno != ENOENT) {
1403 			err = got_error_from_errno();
1404 			goto done;
1405 		}
1406 	} else {
1407 		err = got_fileindex_read(fileindex, index);
1408 		fclose(index);
1409 		if (err)
1410 			goto done;
1411 	}
1412 
1413 	err = got_opentemp_named(&new_fileindex_path, &new_index,
1414 	    fileindex_path);
1415 	if (err)
1416 		goto done;
1417 
1418 	err = ref_base_commit(worktree, repo);
1419 	if (err)
1420 		goto done;
1421 
1422 	err = got_object_open_as_commit(&commit, repo,
1423 	   worktree->base_commit_id);
1424 	if (err)
1425 		goto done;
1426 
1427 	err = got_object_id_by_path(&tree_id, repo,
1428 	    worktree->base_commit_id, worktree->path_prefix);
1429 	if (err)
1430 		goto done;
1431 
1432 	err = got_object_open_as_tree(&tree, repo, tree_id);
1433 	if (err)
1434 		goto done;
1435 
1436 	diff_cb.diff_old_new = diff_old_new;
1437 	diff_cb.diff_old = diff_old;
1438 	diff_cb.diff_new = diff_new;
1439 	arg.fileindex = fileindex;
1440 	arg.worktree = worktree;
1441 	arg.repo = repo;
1442 	arg.progress_cb = progress_cb;
1443 	arg.progress_arg = progress_arg;
1444 	arg.cancel_cb = cancel_cb;
1445 	arg.cancel_arg = cancel_arg;
1446 	checkout_err = got_fileindex_diff_tree(fileindex, tree, repo,
1447 	    &diff_cb, &arg);
1448 
1449 	/* Try to sync the fileindex back to disk in any case. */
1450 	err = got_fileindex_write(fileindex, new_index);
1451 	if (err)
1452 		goto done;
1453 
1454 	if (rename(new_fileindex_path, fileindex_path) != 0) {
1455 		err = got_error_from_errno();
1456 		unlink(new_fileindex_path);
1457 		goto done;
1458 	}
1459 
1460 	free(new_fileindex_path);
1461 	new_fileindex_path = NULL;
1462 
1463 done:
1464 	if (tree)
1465 		got_object_tree_close(tree);
1466 	if (commit)
1467 		got_object_commit_close(commit);
1468 	if (new_fileindex_path)
1469 		unlink(new_fileindex_path);
1470 	if (new_index)
1471 		fclose(new_index);
1472 	free(new_fileindex_path);
1473 	free(fileindex_path);
1474 	got_fileindex_free(fileindex);
1475 	if (checkout_err)
1476 		err = checkout_err;
1477 	unlockerr = lock_worktree(worktree, LOCK_SH);
1478 	if (unlockerr && err == NULL)
1479 		err = unlockerr;
1480 	return err;
1481 }
1482 
1483 struct diff_dir_cb_arg {
1484     struct got_fileindex *fileindex;
1485     struct got_worktree *worktree;
1486     const char *status_path;
1487     size_t status_path_len;
1488     struct got_repository *repo;
1489     got_worktree_status_cb status_cb;
1490     void *status_arg;
1491     got_worktree_cancel_cb cancel_cb;
1492     void *cancel_arg;
1493 };
1494 
1495 static const struct got_error *
1496 report_file_status(struct got_fileindex_entry *ie, const char *abspath,
1497     got_worktree_status_cb status_cb, void *status_arg,
1498     struct got_repository *repo)
1499 {
1500 	const struct got_error *err = NULL;
1501 	unsigned char status = GOT_STATUS_NO_CHANGE;
1502 	struct stat sb;
1503 	struct got_object_id id;
1504 
1505 	err = get_file_status(&status, &sb, ie, abspath, repo);
1506 	if (err == NULL && status != GOT_STATUS_NO_CHANGE) {
1507 		memcpy(id.sha1, ie->blob_sha1, SHA1_DIGEST_LENGTH);
1508 		err = (*status_cb)(status_arg, status, ie->path, &id);
1509 	}
1510 	return err;
1511 }
1512 
1513 static const struct got_error *
1514 status_old_new(void *arg, struct got_fileindex_entry *ie,
1515     struct dirent *de, const char *parent_path)
1516 {
1517 	const struct got_error *err = NULL;
1518 	struct diff_dir_cb_arg *a = arg;
1519 	char *abspath;
1520 
1521 	if (got_path_cmp(parent_path, a->status_path) != 0 &&
1522 	    !got_path_is_child(parent_path, a->status_path, a->status_path_len))
1523 		return NULL;
1524 
1525 	if (parent_path[0]) {
1526 		if (asprintf(&abspath, "%s/%s/%s", a->worktree->root_path,
1527 		    parent_path, de->d_name) == -1)
1528 			return got_error_from_errno();
1529 	} else {
1530 		if (asprintf(&abspath, "%s/%s", a->worktree->root_path,
1531 		    de->d_name) == -1)
1532 			return got_error_from_errno();
1533 	}
1534 
1535 	err = report_file_status(ie, abspath, a->status_cb, a->status_arg,
1536 	    a->repo);
1537 	free(abspath);
1538 	return err;
1539 }
1540 
1541 static const struct got_error *
1542 status_old(void *arg, struct got_fileindex_entry *ie, const char *parent_path)
1543 {
1544 	struct diff_dir_cb_arg *a = arg;
1545 	struct got_object_id id;
1546 	unsigned char status;
1547 
1548 	if (!got_path_is_child(parent_path, a->status_path, a->status_path_len))
1549 		return NULL;
1550 
1551 	memcpy(id.sha1, ie->blob_sha1, SHA1_DIGEST_LENGTH);
1552 	if (got_fileindex_entry_has_file_on_disk(ie))
1553 		status = GOT_STATUS_MISSING;
1554 	else
1555 		status = GOT_STATUS_DELETE;
1556 	return (*a->status_cb)(a->status_arg, status, ie->path, &id);
1557 }
1558 
1559 static const struct got_error *
1560 status_new(void *arg, struct dirent *de, const char *parent_path)
1561 {
1562 	const struct got_error *err = NULL;
1563 	struct diff_dir_cb_arg *a = arg;
1564 	char *path = NULL;
1565 
1566 	if (de->d_type == DT_DIR)
1567 		return NULL;
1568 
1569 	/* XXX ignore symlinks for now */
1570 	if (de->d_type == DT_LNK)
1571 		return NULL;
1572 
1573 	if (!got_path_is_child(parent_path, a->status_path, a->status_path_len))
1574 		return NULL;
1575 
1576 	if (parent_path[0]) {
1577 		if (asprintf(&path, "%s/%s", parent_path, de->d_name) == -1)
1578 			return got_error_from_errno();
1579 	} else {
1580 		path = de->d_name;
1581 	}
1582 
1583 	err = (*a->status_cb)(a->status_arg, GOT_STATUS_UNVERSIONED, path,
1584 	    NULL);
1585 	if (parent_path[0])
1586 		free(path);
1587 	return err;
1588 }
1589 
1590 const struct got_error *
1591 got_worktree_status(struct got_worktree *worktree, const char *path,
1592     struct got_repository *repo, got_worktree_status_cb status_cb,
1593     void *status_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
1594 {
1595 	const struct got_error *err = NULL;
1596 	DIR *workdir = NULL;
1597 	char *fileindex_path = NULL;
1598 	struct got_fileindex *fileindex = NULL;
1599 	FILE *index = NULL;
1600 	struct got_fileindex_diff_dir_cb fdiff_cb;
1601 	struct diff_dir_cb_arg arg;
1602 	char *ondisk_path = NULL;
1603 
1604 	fileindex = got_fileindex_alloc();
1605 	if (fileindex == NULL) {
1606 		err = got_error_from_errno();
1607 		goto done;
1608 	}
1609 
1610 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
1611 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
1612 		err = got_error_from_errno();
1613 		fileindex_path = NULL;
1614 		goto done;
1615 	}
1616 
1617 	index = fopen(fileindex_path, "rb");
1618 	if (index == NULL) {
1619 		if (errno != ENOENT) {
1620 			err = got_error_from_errno();
1621 			goto done;
1622 		}
1623 	} else {
1624 		err = got_fileindex_read(fileindex, index);
1625 		fclose(index);
1626 		if (err)
1627 			goto done;
1628 	}
1629 
1630 	if (asprintf(&ondisk_path, "%s%s%s",
1631 	    worktree->root_path, path[0] ? "/" : "", path) == -1) {
1632 		err = got_error_from_errno();
1633 		goto done;
1634 	}
1635 	workdir = opendir(ondisk_path);
1636 	if (workdir == NULL) {
1637 		if (errno == ENOTDIR || errno == ENOENT) {
1638 			struct got_fileindex_entry *ie;
1639 			ie = got_fileindex_entry_get(fileindex, path);
1640 			if (ie == NULL) {
1641 				err = got_error(GOT_ERR_BAD_PATH);
1642 				goto done;
1643 			}
1644 			err = report_file_status(ie, ondisk_path,
1645 			    status_cb, status_arg, repo);
1646 			goto done;
1647 		} else {
1648 			err = got_error_from_errno();
1649 			goto done;
1650 		}
1651 	}
1652 	fdiff_cb.diff_old_new = status_old_new;
1653 	fdiff_cb.diff_old = status_old;
1654 	fdiff_cb.diff_new = status_new;
1655 	arg.fileindex = fileindex;
1656 	arg.worktree = worktree;
1657 	arg.status_path = path;
1658 	arg.status_path_len = strlen(path);
1659 	arg.repo = repo;
1660 	arg.status_cb = status_cb;
1661 	arg.status_arg = status_arg;
1662 	arg.cancel_cb = cancel_cb;
1663 	arg.cancel_arg = cancel_arg;
1664 	err = got_fileindex_diff_dir(fileindex, workdir, worktree->root_path,
1665 	    path, repo, &fdiff_cb, &arg);
1666 done:
1667 	if (workdir)
1668 		closedir(workdir);
1669 	free(ondisk_path);
1670 	free(fileindex_path);
1671 	got_fileindex_free(fileindex);
1672 	return err;
1673 }
1674 
1675 const struct got_error *
1676 got_worktree_resolve_path(char **wt_path, struct got_worktree *worktree,
1677     const char *arg)
1678 {
1679 	const struct got_error *err = NULL;
1680 	char *resolved, *path = NULL;
1681 	size_t len;
1682 
1683 	*wt_path = NULL;
1684 
1685 	resolved = realpath(arg, NULL);
1686 	if (resolved == NULL)
1687 		return got_error_from_errno();
1688 
1689 	if (strncmp(got_worktree_get_root_path(worktree), resolved,
1690 	    strlen(got_worktree_get_root_path(worktree)))) {
1691 		err = got_error(GOT_ERR_BAD_PATH);
1692 		goto done;
1693 	}
1694 
1695 	path = strdup(resolved + strlen(got_worktree_get_root_path(worktree)));
1696 	if (path == NULL) {
1697 		err = got_error_from_errno();
1698 		goto done;
1699 	}
1700 
1701 	/* XXX status walk can't deal with trailing slash! */
1702 	len = strlen(path);
1703 	while (path[len - 1] == '/') {
1704 		path[len - 1] = '\0';
1705 		len--;
1706 	}
1707 done:
1708 	free(resolved);
1709 	if (err == NULL)
1710 		*wt_path = path;
1711 	else
1712 		free(path);
1713 	return err;
1714 }
1715 
1716 const struct got_error *
1717 got_worktree_schedule_add(struct got_worktree *worktree,
1718     const char *ondisk_path, got_worktree_status_cb status_cb, void *status_arg,
1719     struct got_repository *repo)
1720 {
1721 	struct got_fileindex *fileindex = NULL;
1722 	struct got_fileindex_entry *ie = NULL;
1723 	char *relpath, *fileindex_path = NULL, *new_fileindex_path = NULL;
1724 	FILE *index = NULL, *new_index = NULL;
1725 	const struct got_error *err = NULL, *unlockerr = NULL;
1726 	int ie_added = 0;
1727 
1728 	err = lock_worktree(worktree, LOCK_EX);
1729 	if (err)
1730 		return err;
1731 
1732 	err = got_path_skip_common_ancestor(&relpath,
1733 	    got_worktree_get_root_path(worktree), ondisk_path);
1734 	if (err)
1735 		goto done;
1736 
1737 	fileindex = got_fileindex_alloc();
1738 	if (fileindex == NULL) {
1739 		err = got_error_from_errno();
1740 		goto done;
1741 	}
1742 
1743 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
1744 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
1745 		err = got_error_from_errno();
1746 		fileindex_path = NULL;
1747 		goto done;
1748 	}
1749 
1750 	index = fopen(fileindex_path, "rb");
1751 	if (index == NULL) {
1752 		err = got_error_from_errno();
1753 		goto done;
1754 	}
1755 
1756 	err = got_fileindex_read(fileindex, index);
1757 	if (err)
1758 		goto done;
1759 
1760 	if (got_fileindex_entry_get(fileindex, relpath) != NULL) {
1761 		err = got_error_set_errno(EEXIST);
1762 		goto done;
1763 	}
1764 
1765 	err = got_fileindex_entry_alloc(&ie, ondisk_path, relpath, NULL, NULL);
1766 	if (err)
1767 		goto done;
1768 
1769 	err = got_fileindex_entry_add(fileindex, ie);
1770 	if (err)
1771 		goto done;
1772 	ie_added = 1; /* now owned by fileindex; don't free separately */
1773 
1774 	err = got_opentemp_named(&new_fileindex_path, &new_index,
1775 	    fileindex_path);
1776 	if (err)
1777 		goto done;
1778 
1779 	err = got_fileindex_write(fileindex, new_index);
1780 	if (err)
1781 		goto done;
1782 
1783 	if (rename(new_fileindex_path, fileindex_path) != 0) {
1784 		err = got_error_from_errno();
1785 		goto done;
1786 	}
1787 
1788 	free(new_fileindex_path);
1789 	new_fileindex_path = NULL;
1790 
1791 	err = report_file_status(ie, ondisk_path, status_cb, status_arg, repo);
1792 done:
1793 	if (index) {
1794 		if (fclose(index) != 0 && err == NULL)
1795 			err = got_error_from_errno();
1796 	}
1797 	if (new_fileindex_path) {
1798 		if (unlink(new_fileindex_path) != 0 && err == NULL)
1799 			err = got_error_from_errno();
1800 		free(new_fileindex_path);
1801 	}
1802 	if (ie && !ie_added)
1803 		got_fileindex_entry_free(ie);
1804 	if (fileindex)
1805 		got_fileindex_free(fileindex);
1806 	unlockerr = lock_worktree(worktree, LOCK_SH);
1807 	if (unlockerr && err == NULL)
1808 		err = unlockerr;
1809 	free(relpath);
1810 	return err;
1811 }
1812 
1813 const struct got_error *
1814 got_worktree_schedule_delete(struct got_worktree *worktree,
1815     const char *ondisk_path, int delete_local_mods,
1816     got_worktree_status_cb status_cb, void *status_arg,
1817     struct got_repository *repo)
1818 {
1819 	struct got_fileindex *fileindex = NULL;
1820 	struct got_fileindex_entry *ie = NULL;
1821 	char *relpath, *fileindex_path = NULL, *new_fileindex_path = NULL;
1822 	FILE *index = NULL, *new_index = NULL;
1823 	const struct got_error *err = NULL, *unlockerr = NULL;
1824 	unsigned char status;
1825 	struct stat sb;
1826 
1827 	err = lock_worktree(worktree, LOCK_EX);
1828 	if (err)
1829 		return err;
1830 
1831 	err = got_path_skip_common_ancestor(&relpath,
1832 	    got_worktree_get_root_path(worktree), ondisk_path);
1833 	if (err)
1834 		goto done;
1835 
1836 	fileindex = got_fileindex_alloc();
1837 	if (fileindex == NULL) {
1838 		err = got_error_from_errno();
1839 		goto done;
1840 	}
1841 
1842 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
1843 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
1844 		err = got_error_from_errno();
1845 		fileindex_path = NULL;
1846 		goto done;
1847 	}
1848 
1849 	index = fopen(fileindex_path, "rb");
1850 	if (index == NULL) {
1851 		err = got_error_from_errno();
1852 		goto done;
1853 	}
1854 
1855 	err = got_fileindex_read(fileindex, index);
1856 	if (err)
1857 		goto done;
1858 
1859 	ie = got_fileindex_entry_get(fileindex, relpath);
1860 	if (ie == NULL) {
1861 		err = got_error(GOT_ERR_BAD_PATH);
1862 		goto done;
1863 	}
1864 
1865 	err = get_file_status(&status, &sb, ie, ondisk_path, repo);
1866 	if (err)
1867 		goto done;
1868 
1869 	if (status != GOT_STATUS_NO_CHANGE) {
1870 		if (status == GOT_STATUS_DELETE) {
1871 			err = got_error_set_errno(ENOENT);
1872 			goto done;
1873 		}
1874 		if (status != GOT_STATUS_MODIFY) {
1875 			err = got_error(GOT_ERR_FILE_STATUS);
1876 			goto done;
1877 		}
1878 		if (!delete_local_mods) {
1879 			err = got_error(GOT_ERR_FILE_MODIFIED);
1880 			goto done;
1881 		}
1882 	}
1883 
1884 	if (unlink(ondisk_path) != 0) {
1885 		err = got_error_from_errno();
1886 		goto done;
1887 	}
1888 
1889 	got_fileindex_entry_mark_deleted_from_disk(ie);
1890 
1891 	err = got_opentemp_named(&new_fileindex_path, &new_index,
1892 	    fileindex_path);
1893 	if (err)
1894 		goto done;
1895 
1896 	err = got_fileindex_write(fileindex, new_index);
1897 	if (err)
1898 		goto done;
1899 
1900 	if (rename(new_fileindex_path, fileindex_path) != 0) {
1901 		err = got_error_from_errno();
1902 		goto done;
1903 	}
1904 
1905 	free(new_fileindex_path);
1906 	new_fileindex_path = NULL;
1907 
1908 	err = report_file_status(ie, ondisk_path, status_cb, status_arg, repo);
1909 done:
1910 	free(relpath);
1911 	if (index) {
1912 		if (fclose(index) != 0 && err == NULL)
1913 			err = got_error_from_errno();
1914 	}
1915 	if (new_fileindex_path) {
1916 		if (unlink(new_fileindex_path) != 0 && err == NULL)
1917 			err = got_error_from_errno();
1918 		free(new_fileindex_path);
1919 	}
1920 	if (fileindex)
1921 		got_fileindex_free(fileindex);
1922 	unlockerr = lock_worktree(worktree, LOCK_SH);
1923 	if (unlockerr && err == NULL)
1924 		err = unlockerr;
1925 	return err;
1926 }