1 /*
2  * Copyright (c) 2018 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 
21 #include <string.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <fcntl.h>
25 #include <errno.h>
26 #include <unistd.h>
27 #include <sha1.h>
28 #include <zlib.h>
29 #include <fnmatch.h>
30 #include <libgen.h>
31 
32 #include "got_error.h"
33 #include "got_repository.h"
34 #include "got_reference.h"
35 #include "got_object.h"
36 #include "got_worktree.h"
37 #include "got_opentemp.h"
38 
39 #include "got_lib_worktree.h"
40 #include "got_lib_path.h"
41 #include "got_lib_sha1.h"
42 #include "got_lib_fileindex.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_object.h"
46 
47 #ifndef MIN
48 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
49 #endif
50 
51 static const struct got_error *
52 create_meta_file(const char *path_got, const char *name, const char *content)
53 {
54 	const struct got_error *err = NULL;
55 	char *path;
56 	int fd = -1;
57 
58 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
59 		err = got_error_from_errno();
60 		path = NULL;
61 		goto done;
62 	}
63 
64 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
65 	    GOT_DEFAULT_FILE_MODE);
66 	if (fd == -1) {
67 		err = got_error_from_errno();
68 		goto done;
69 	}
70 
71 	if (content) {
72 		int len = dprintf(fd, "%s\n", content);
73 		if (len != strlen(content) + 1) {
74 			err = got_error_from_errno();
75 			goto done;
76 		}
77 	}
78 
79 done:
80 	if (fd != -1 && close(fd) == -1 && err == NULL)
81 		err = got_error_from_errno();
82 	free(path);
83 	return err;
84 }
85 
86 static const struct got_error *
87 update_meta_file(const char *path_got, const char *name, const char *content)
88 {
89 	const struct got_error *err = NULL;
90 	FILE *tmpfile = NULL;
91 	char *tmppath = NULL;
92 	char *path = NULL;
93 
94 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
95 		err = got_error_from_errno();
96 		path = NULL;
97 		goto done;
98 	}
99 
100 	err = got_opentemp_named(&tmppath, &tmpfile, path);
101 	if (err)
102 		goto done;
103 
104 	if (content) {
105 		int len = fprintf(tmpfile, "%s\n", content);
106 		if (len != strlen(content) + 1) {
107 			err = got_error_from_errno();
108 			goto done;
109 		}
110 	}
111 
112 	if (rename(tmppath, path) != 0) {
113 		err = got_error_from_errno();
114 		goto done;
115 	}
116 
117 done:
118 	free(tmppath);
119 	fclose(tmpfile);
120 	return err;
121 }
122 
123 static const struct got_error *
124 read_meta_file(char **content, const char *path_got, const char *name)
125 {
126 	const struct got_error *err = NULL;
127 	char *path;
128 	int fd = -1;
129 	ssize_t n;
130 	struct stat sb;
131 
132 	*content = NULL;
133 
134 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
135 		err = got_error_from_errno();
136 		path = NULL;
137 		goto done;
138 	}
139 
140 	fd = open(path, O_RDONLY | O_NOFOLLOW);
141 	if (fd == -1) {
142 		err = got_error_from_errno();
143 		goto done;
144 	}
145 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
146 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
147 		    : got_error_from_errno());
148 		goto done;
149 	}
150 
151 	stat(path, &sb);
152 	*content = calloc(1, sb.st_size);
153 	if (*content == NULL) {
154 		err = got_error_from_errno();
155 		goto done;
156 	}
157 
158 	n = read(fd, *content, sb.st_size);
159 	if (n != sb.st_size) {
160 		err = (n == -1 ? got_error_from_errno() :
161 		    got_error(GOT_ERR_WORKTREE_META));
162 		goto done;
163 	}
164 	if ((*content)[sb.st_size - 1] != '\n') {
165 		err = got_error(GOT_ERR_WORKTREE_META);
166 		goto done;
167 	}
168 	(*content)[sb.st_size - 1] = '\0';
169 
170 done:
171 	if (fd != -1 && close(fd) == -1 && err == NULL)
172 		err = got_error_from_errno();
173 	free(path);
174 	if (err) {
175 		free(*content);
176 		*content = NULL;
177 	}
178 	return err;
179 }
180 
181 const struct got_error *
182 got_worktree_init(const char *path, struct got_reference *head_ref,
183     const char *prefix, struct got_repository *repo)
184 {
185 	const struct got_error *err = NULL;
186 	struct got_object_id *commit_id = NULL;
187 	int obj_type;
188 	char *path_got = NULL;
189 	char *refstr = NULL;
190 	char *repo_path = NULL;
191 	char *formatstr = NULL;
192 	char *absprefix = NULL;
193 	char *basestr = NULL;
194 
195 	err = got_ref_resolve(&commit_id, repo, head_ref);
196 	if (err)
197 		return err;
198 	err = got_object_get_type(&obj_type, repo, commit_id);
199 	if (err)
200 		return err;
201 	if (obj_type != GOT_OBJ_TYPE_COMMIT)
202 		return got_error(GOT_ERR_OBJ_TYPE);
203 
204 	if (!got_path_is_absolute(prefix)) {
205 		if (asprintf(&absprefix, "/%s", prefix) == -1)
206 			return got_error_from_errno();
207 	}
208 
209 	/* Create top-level directory (may already exist). */
210 	if (mkdir(path, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
211 		err = got_error_from_errno();
212 		goto done;
213 	}
214 
215 	/* Create .got directory (may already exist). */
216 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
217 		err = got_error_from_errno();
218 		goto done;
219 	}
220 	if (mkdir(path_got, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
221 		err = got_error_from_errno();
222 		goto done;
223 	}
224 
225 	/* Create an empty lock file. */
226 	err = create_meta_file(path_got, GOT_WORKTREE_LOCK, NULL);
227 	if (err)
228 		goto done;
229 
230 	/* Create an empty file index. */
231 	err = create_meta_file(path_got, GOT_WORKTREE_FILE_INDEX, NULL);
232 	if (err)
233 		goto done;
234 
235 	/* Write the HEAD reference. */
236 	refstr = got_ref_to_str(head_ref);
237 	if (refstr == NULL) {
238 		err = got_error_from_errno();
239 		goto done;
240 	}
241 	err = create_meta_file(path_got, GOT_WORKTREE_HEAD_REF, refstr);
242 	if (err)
243 		goto done;
244 
245 	/* Record our base commit. */
246 	err = got_object_id_str(&basestr, commit_id);
247 	if (err)
248 		goto done;
249 	err = create_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, basestr);
250 	if (err)
251 		goto done;
252 
253 	/* Store path to repository. */
254 	repo_path = got_repo_get_path(repo);
255 	if (repo_path == NULL) {
256 		err = got_error_from_errno();
257 		goto done;
258 	}
259 	err = create_meta_file(path_got, GOT_WORKTREE_REPOSITORY, repo_path);
260 	if (err)
261 		goto done;
262 
263 	/* Store in-repository path prefix. */
264 	err = create_meta_file(path_got, GOT_WORKTREE_PATH_PREFIX,
265 	    absprefix ? absprefix : prefix);
266 	if (err)
267 		goto done;
268 
269 	/* Stamp work tree with format file. */
270 	if (asprintf(&formatstr, "%d", GOT_WORKTREE_FORMAT_VERSION) == -1) {
271 		err = got_error_from_errno();
272 		goto done;
273 	}
274 	err = create_meta_file(path_got, GOT_WORKTREE_FORMAT, formatstr);
275 	if (err)
276 		goto done;
277 
278 done:
279 	free(commit_id);
280 	free(path_got);
281 	free(formatstr);
282 	free(refstr);
283 	free(repo_path);
284 	free(absprefix);
285 	free(basestr);
286 	return err;
287 }
288 
289 const struct got_error *
290 got_worktree_open(struct got_worktree **worktree, const char *path)
291 {
292 	const struct got_error *err = NULL;
293 	char *path_got;
294 	char *formatstr = NULL;
295 	char *path_lock = NULL;
296 	char *base_commit_id_str = NULL;
297 	char *head_ref_str = NULL;
298 	int version, fd = -1;
299 	const char *errstr;
300 	struct got_repository *repo = NULL;
301 
302 	*worktree = NULL;
303 
304 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
305 		err = got_error_from_errno();
306 		path_got = NULL;
307 		goto done;
308 	}
309 
310 	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
311 		err = got_error_from_errno();
312 		path_lock = NULL;
313 		goto done;
314 	}
315 
316 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK);
317 	if (fd == -1) {
318 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
319 		    : got_error_from_errno());
320 		goto done;
321 	}
322 
323 	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
324 	if (err)
325 		goto done;
326 
327 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
328 	if (errstr) {
329 		err = got_error(GOT_ERR_WORKTREE_META);
330 		goto done;
331 	}
332 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
333 		err = got_error(GOT_ERR_WORKTREE_VERS);
334 		goto done;
335 	}
336 
337 	*worktree = calloc(1, sizeof(**worktree));
338 	if (*worktree == NULL) {
339 		err = got_error_from_errno();
340 		goto done;
341 	}
342 	(*worktree)->lockfd = -1;
343 
344 	(*worktree)->root_path = strdup(path);
345 	if ((*worktree)->root_path == NULL) {
346 		err = got_error_from_errno();
347 		goto done;
348 	}
349 	err = read_meta_file(&(*worktree)->repo_path, path_got,
350 	    GOT_WORKTREE_REPOSITORY);
351 	if (err)
352 		goto done;
353 
354 	err = read_meta_file(&(*worktree)->path_prefix, path_got,
355 	    GOT_WORKTREE_PATH_PREFIX);
356 	if (err)
357 		goto done;
358 
359 	err = read_meta_file(&base_commit_id_str, path_got,
360 	    GOT_WORKTREE_BASE_COMMIT);
361 	if (err)
362 		goto done;
363 
364 	err = got_repo_open(&repo, (*worktree)->repo_path);
365 	if (err)
366 		goto done;
367 
368 	err = got_object_resolve_id_str(&(*worktree)->base_commit_id, repo,
369 	    base_commit_id_str);
370 	if (err)
371 		goto done;
372 
373 	err = read_meta_file(&head_ref_str, path_got, GOT_WORKTREE_HEAD_REF);
374 	if (err)
375 		goto done;
376 
377 	err = got_ref_open(&(*worktree)->head_ref, repo, head_ref_str);
378 done:
379 	if (repo)
380 		got_repo_close(repo);
381 	free(path_got);
382 	free(path_lock);
383 	free(head_ref_str);
384 	free(base_commit_id_str);
385 	if (err) {
386 		if (fd != -1)
387 			close(fd);
388 		if (*worktree != NULL)
389 			got_worktree_close(*worktree);
390 		*worktree = NULL;
391 	} else
392 		(*worktree)->lockfd = fd;
393 
394 	return err;
395 }
396 
397 void
398 got_worktree_close(struct got_worktree *worktree)
399 {
400 	free(worktree->root_path);
401 	free(worktree->repo_path);
402 	free(worktree->path_prefix);
403 	free(worktree->base_commit_id);
404 	if (worktree->head_ref)
405 		got_ref_close(worktree->head_ref);
406 	if (worktree->lockfd != -1)
407 		close(worktree->lockfd);
408 	free(worktree);
409 }
410 
411 const char *
412 got_worktree_get_repo_path(struct got_worktree *worktree)
413 {
414 	return worktree->repo_path;
415 }
416 
417 const char *
418 got_worktree_get_path_prefix(struct got_worktree *worktree)
419 {
420 	return worktree->path_prefix;
421 }
422 
423 const struct got_error *
424 got_worktree_match_path_prefix(int *match, struct got_worktree *worktree,
425     const char *path_prefix)
426 {
427 	char *absprefix = NULL;
428 
429 	if (!got_path_is_absolute(path_prefix)) {
430 		if (asprintf(&absprefix, "/%s", path_prefix) == -1)
431 			return got_error_from_errno();
432 	}
433 	*match = (strcmp(absprefix ? absprefix : path_prefix,
434 	    worktree->path_prefix) == 0);
435 	free(absprefix);
436 	return NULL;
437 }
438 
439 char *
440 got_worktree_get_head_ref_name(struct got_worktree *worktree)
441 {
442 	return got_ref_to_str(worktree->head_ref);
443 }
444 
445 struct got_reference *
446 got_worktree_get_head_ref(struct got_worktree *worktree)
447 {
448 	return got_ref_dup(worktree->head_ref);
449 }
450 
451 const struct got_object_id *
452 got_worktree_get_base_commit_id(struct got_worktree *worktree)
453 {
454 	return worktree->base_commit_id;
455 }
456 
457 const struct got_error *
458 got_worktree_set_base_commit_id(struct got_worktree *worktree,
459     struct got_repository *repo, struct got_object_id *commit_id)
460 {
461 	const struct got_error *err;
462 	struct got_object *obj = NULL;
463 	char *id_str = NULL;
464 	char *path_got = NULL;
465 
466 	if (asprintf(&path_got, "%s/%s", worktree->root_path,
467 	    GOT_WORKTREE_GOT_DIR) == -1) {
468 		err = got_error_from_errno();
469 		path_got = NULL;
470 		goto done;
471 	}
472 
473 	err = got_object_open(&obj, repo, commit_id);
474 	if (err)
475 		return err;
476 
477 	if (obj->type != GOT_OBJ_TYPE_COMMIT) {
478 		err = got_error(GOT_ERR_OBJ_TYPE);
479 		goto done;
480 	}
481 
482 	/* Record our base commit. */
483 	err = got_object_id_str(&id_str, commit_id);
484 	if (err)
485 		goto done;
486 	err = update_meta_file(path_got, GOT_WORKTREE_BASE_COMMIT, id_str);
487 	if (err)
488 		goto done;
489 
490 	free(worktree->base_commit_id);
491 	worktree->base_commit_id = got_object_id_dup(commit_id);
492 	if (worktree->base_commit_id == NULL) {
493 		err = got_error_from_errno();
494 		goto done;
495 	}
496 done:
497 	if (obj)
498 		got_object_close(obj);
499 	free(id_str);
500 	free(path_got);
501 	return err;
502 }
503 
504 static const struct got_error *
505 lock_worktree(struct got_worktree *worktree, int operation)
506 {
507 	if (flock(worktree->lockfd, operation | LOCK_NB) == -1)
508 		return (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
509 		    : got_error_from_errno());
510 	return NULL;
511 }
512 
513 static const char *
514 apply_path_prefix(struct got_worktree *worktree, const char *path)
515 {
516 	const char *p = path;
517 	p += strlen(worktree->path_prefix);
518 	if (*p == '/')
519 		p++;
520 	return p;
521 }
522 
523 static const struct got_error *
524 blob_checkout(struct got_worktree *worktree, struct got_fileindex *fileindex,
525    struct got_fileindex_entry *entry, const char *path,
526    struct got_blob_object *blob, struct got_repository *repo,
527    got_worktree_checkout_cb progress_cb, void *progress_arg,
528    const char *progress_path)
529 {
530 	const struct got_error *err = NULL;
531 	char *ondisk_path;
532 	int fd = -1;
533 	size_t len, hdrlen;
534 	int update = 0;
535 	char *tmppath = NULL;
536 
537 	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path,
538 	    apply_path_prefix(worktree, path)) == -1)
539 		return got_error_from_errno();
540 
541 	fd = open(ondisk_path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
542 	    GOT_DEFAULT_FILE_MODE);
543 	if (fd == -1) {
544 		err = got_error_from_errno();
545 		if (errno == EEXIST) {
546 			struct stat sb;
547 			if (lstat(ondisk_path, &sb) == -1) {
548 				err = got_error_from_errno();
549 				goto done;
550 			} else if (!S_ISREG(sb.st_mode)) {
551 				/* TODO file is obstructed; do something */
552 				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
553 				goto done;
554 			} else {
555 				err = got_opentemp_named_fd(&tmppath, &fd,
556 				    ondisk_path);
557 				if (err)
558 					goto done;
559 				update = 1;
560 			}
561 		} else
562 			return err;
563 	}
564 
565 	(*progress_cb)(progress_arg,
566 	    update ? GOT_STATUS_UPDATE : GOT_STATUS_ADD, progress_path);
567 
568 	hdrlen = got_object_blob_get_hdrlen(blob);
569 	do {
570 		const uint8_t *buf = got_object_blob_get_read_buf(blob);
571 		err = got_object_blob_read_block(&len, blob);
572 		if (err)
573 			break;
574 		if (len > 0) {
575 			/* Skip blob object header first time around. */
576 			ssize_t outlen = write(fd, buf + hdrlen, len - hdrlen);
577 			if (outlen == -1) {
578 				err = got_error_from_errno();
579 				goto done;
580 			} else if (outlen != len - hdrlen) {
581 				err = got_error(GOT_ERR_IO);
582 				goto done;
583 			}
584 			hdrlen = 0;
585 		}
586 	} while (len != 0);
587 
588 	fsync(fd);
589 
590 	if (update) {
591 		if (rename(tmppath, ondisk_path) != 0) {
592 			err = got_error_from_errno();
593 			goto done;
594 		}
595 	}
596 
597 	if (entry)
598 		err = got_fileindex_entry_update(entry, ondisk_path,
599 		    blob->id.sha1, worktree->base_commit_id->sha1);
600 	else {
601 		err = got_fileindex_entry_alloc(&entry, ondisk_path,
602 		    apply_path_prefix(worktree, path), blob->id.sha1,
603 		    worktree->base_commit_id->sha1);
604 		if (err)
605 			goto done;
606 		err = got_fileindex_entry_add(fileindex, entry);
607 	}
608 	if (err)
609 		goto done;
610 done:
611 	if (fd != -1)
612 		close(fd);
613 	free(ondisk_path);
614 	free(tmppath);
615 	return err;
616 }
617 
618 static const struct got_error *
619 add_dir_on_disk(struct got_worktree *worktree, const char *path)
620 {
621 	const struct got_error *err = NULL;
622 	char *abspath;
623 
624 	if (asprintf(&abspath, "%s/%s", worktree->root_path,
625 	    apply_path_prefix(worktree, path)) == -1)
626 		return got_error_from_errno();
627 
628 	/* XXX queue work rather than editing disk directly? */
629 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
630 		struct stat sb;
631 
632 		if (errno != EEXIST) {
633 			err = got_error_from_errno();
634 			goto done;
635 		}
636 
637 		if (lstat(abspath, &sb) == -1) {
638 			err = got_error_from_errno();
639 			goto done;
640 		}
641 
642 		if (!S_ISDIR(sb.st_mode)) {
643 			/* TODO directory is obstructed; do something */
644 			return got_error(GOT_ERR_FILE_OBSTRUCTED);
645 		}
646 	}
647 
648 done:
649 	free(abspath);
650 	return err;
651 }
652 
653 static const struct got_error *
654 tree_checkout(struct got_worktree *, struct got_fileindex *,
655     struct got_tree_object *, const char *, struct got_repository *,
656     got_worktree_checkout_cb progress_cb, void *progress_arg,
657     got_worktree_cancel_cb cancel_cb, void *cancel_arg);
658 
659 static const struct got_error *
660 tree_checkout_entry(struct got_worktree *worktree,
661     struct got_fileindex *fileindex, struct got_tree_entry *te,
662     const char *parent, struct got_repository *repo,
663     got_worktree_checkout_cb progress_cb, void *progress_arg,
664     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
665 {
666 	const struct got_error *err = NULL;
667 	struct got_object *obj = NULL;
668 	struct got_blob_object *blob = NULL;
669 	struct got_fileindex_entry *entry = NULL;
670 	struct got_tree_object *tree = NULL;
671 	char *path = NULL;
672 	char *progress_path = NULL;
673 	size_t len;
674 
675 	if (parent[0] == '/' && parent[1] == '\0')
676 		parent = "";
677 	if (asprintf(&path, "%s/%s", parent, te->name) == -1)
678 		return got_error_from_errno();
679 
680 	/* Skip this entry if it is outside of our path prefix. */
681 	len = MIN(strlen(worktree->path_prefix), strlen(path));
682 	if (strncmp(path, worktree->path_prefix, len) != 0) {
683 		free(path);
684 		return NULL;
685 	}
686 
687 	err = got_object_open(&obj, repo, te->id);
688 	if (err)
689 		goto done;
690 
691 	progress_path = path;
692 	if (strncmp(progress_path, worktree->path_prefix, len) == 0)
693 		progress_path += len;
694 
695 	switch (obj->type) {
696 	case GOT_OBJ_TYPE_BLOB:
697 		if (strlen(worktree->path_prefix) >= strlen(path))
698 			break;
699 		entry = got_fileindex_entry_get(fileindex,
700 		    apply_path_prefix(worktree, path));
701 		if (entry &&
702 		    memcmp(entry->commit_sha1, worktree->base_commit_id->sha1,
703 		    SHA1_DIGEST_LENGTH) == 0) {
704 			(*progress_cb)(progress_arg, GOT_STATUS_EXISTS,
705 			    progress_path);
706 			break;
707 		}
708 		if (entry && memcmp(entry->blob_sha1, obj->id.sha1,
709 		    SHA1_DIGEST_LENGTH) == 0)
710 			break;
711 		err = got_object_blob_open(&blob, repo, obj, 8192);
712 		if (err)
713 			goto done;
714 		err = blob_checkout(worktree, fileindex, entry, path, blob,
715 		    repo, progress_cb, progress_arg, progress_path);
716 		break;
717 	case GOT_OBJ_TYPE_TREE:
718 		if (strlen(worktree->path_prefix) < strlen(path)) {
719 			err = add_dir_on_disk(worktree, path);
720 			if (err)
721 				break;
722 		}
723 		err = got_object_tree_open(&tree, repo, obj);
724 		if (err)
725 			goto done;
726 		/* XXX infinite recursion possible */
727 		err = tree_checkout(worktree, fileindex, tree, path, repo,
728 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
729 		break;
730 	default:
731 		break;
732 	}
733 
734 done:
735 	if (blob)
736 		got_object_blob_close(blob);
737 	if (tree)
738 		got_object_tree_close(tree);
739 	if (obj)
740 		got_object_close(obj);
741 	free(path);
742 	return err;
743 }
744 
745 struct collect_missing_entry_args {
746 	struct got_fileindex *fileindex;
747 	const struct got_tree_entries *entries;
748 	struct got_fileindex missing_entries;
749 	const char *path_prefix;
750 };
751 
752 static const struct got_error *
753 collect_missing_file(void *args, struct got_fileindex_entry *entry)
754 {
755 	struct collect_missing_entry_args *a = args;
756 	char *name;
757 	struct got_tree_entry *te;
758 	int found = 0;
759 
760 	if (a->path_prefix[0] == '\0' && strchr(entry->path, '/') != NULL)
761 		return NULL;
762 	if (a->path_prefix[0] != '\0' &&
763 	    strncmp(a->path_prefix, entry->path, strlen(a->path_prefix)) != 0)
764 		return NULL;
765 
766 	name = basename(entry->path);
767 	if (name == NULL)
768 		return got_error_from_errno();
769 
770 	SIMPLEQ_FOREACH(te, &a->entries->head, entry) {
771 		if (strcmp(te->name, name) == 0) {
772 			found = 1;
773 			break;
774 		}
775 	}
776 
777 	if (found)
778 		return NULL;
779 
780 	got_fileindex_entry_remove(a->fileindex, entry);
781 	return got_fileindex_entry_add(&a->missing_entries, entry);
782 }
783 
784 /* Remove files which exist in the file index but not in the tree. */
785 static const struct got_error *
786 remove_missing_files(struct got_worktree *worktree, const char *path,
787     struct got_fileindex *fileindex, const struct got_tree_entries *entries,
788     got_worktree_checkout_cb progress_cb, void *progress_arg,
789     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
790 {
791 	const struct got_error *err = NULL;
792 	struct collect_missing_entry_args a;
793 	struct got_fileindex_entry *entry, *tmp;
794 
795 	a.fileindex = fileindex;
796 	a.entries = entries;
797 	a.missing_entries.nentries = 0;
798 	a.path_prefix = path;
799 	while (a.path_prefix[0] == '/')
800 		a.path_prefix++;
801 	TAILQ_INIT(&a.missing_entries.entries);
802 	err = got_fileindex_for_each_entry(fileindex, collect_missing_file, &a);
803 	if (err)
804 		return err;
805 
806 	TAILQ_FOREACH_SAFE(entry, &a.missing_entries.entries, entry, tmp) {
807 		char *ondisk_path = NULL;
808 
809 		if (cancel_cb) {
810 			err = (*cancel_cb)(cancel_arg);
811 			if (err)
812 				break;
813 		}
814 
815 		(*progress_cb)(progress_arg, GOT_STATUS_DELETE, entry->path);
816 
817 		if (asprintf(&ondisk_path, "%s/%s", worktree->root_path,
818 		    entry->path) == -1) {
819 			err = got_error_from_errno();
820 			break;
821 		}
822 
823 		if (unlink(ondisk_path) == -1)
824 			err = got_error_from_errno();
825 		free(ondisk_path);
826 		if (err)
827 			break;
828 
829 		TAILQ_REMOVE(&a.missing_entries.entries, entry, entry);
830 		got_fileindex_entry_free(entry);
831 	}
832 
833 	if (err) {
834 		while (!TAILQ_EMPTY(&a.missing_entries.entries)) {
835 			entry = TAILQ_FIRST(&a.missing_entries.entries);
836 			TAILQ_REMOVE(&a.missing_entries.entries, entry, entry);
837 			got_fileindex_entry_free(entry);
838 		}
839 	}
840 
841 	return err;
842 }
843 
844 static const struct got_error *
845 tree_checkout(struct got_worktree *worktree,
846     struct got_fileindex *fileindex, struct got_tree_object *tree,
847     const char *path, struct got_repository *repo,
848     got_worktree_checkout_cb progress_cb, void *progress_arg,
849     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
850 {
851 	const struct got_error *err = NULL;
852 	const struct got_tree_entries *entries;
853 	struct got_tree_entry *te;
854 	size_t len;
855 
856 	/* Skip this tree if it is outside of our path prefix. */
857 	len = MIN(strlen(worktree->path_prefix), strlen(path));
858 	if (strncmp(path, worktree->path_prefix, len) != 0)
859 		return NULL;
860 
861 	entries = got_object_tree_get_entries(tree);
862 	SIMPLEQ_FOREACH(te, &entries->head, entry) {
863 		if (cancel_cb) {
864 			err = (*cancel_cb)(cancel_arg);
865 			if (err)
866 				return err;
867 		}
868 		err = tree_checkout_entry(worktree, fileindex, te, path, repo,
869 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
870 		if (err)
871 			return err;
872 	}
873 
874 	len = strlen(worktree->path_prefix);
875 	if (strncmp(worktree->path_prefix, path, len) == 0) {
876 		err = remove_missing_files(worktree, path, fileindex, entries,
877 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
878 		if (err)
879 			return err;
880 	}
881 
882 	return err;
883 }
884 
885 const struct got_error *
886 got_worktree_checkout_files(struct got_worktree *worktree,
887     struct got_repository *repo, got_worktree_checkout_cb progress_cb,
888     void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
889 {
890 	const struct got_error *err = NULL, *unlockerr, *checkout_err = NULL;
891 	struct got_commit_object *commit = NULL;
892 	struct got_tree_object *tree = NULL;
893 	char *fileindex_path = NULL, *new_fileindex_path = NULL;
894 	struct got_fileindex *fileindex = NULL;
895 	FILE *index = NULL, *new_index = NULL;
896 
897 	err = lock_worktree(worktree, LOCK_EX);
898 	if (err)
899 		return err;
900 
901 	fileindex = got_fileindex_alloc();
902 	if (fileindex == NULL) {
903 		err = got_error_from_errno();
904 		goto done;
905 	}
906 
907 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
908 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
909 		err = got_error_from_errno();
910 		fileindex_path = NULL;
911 		goto done;
912 	}
913 
914 	/*
915 	 * Read the file index.
916 	 * Checking out files is supposed to be an idempotent operation.
917 	 * If the on-disk file index is incomplete we will try to complete it.
918 	 */
919 	index = fopen(fileindex_path, "rb");
920 	if (index == NULL) {
921 		err = got_error_from_errno();
922 		goto done;
923 	}
924 	err = got_fileindex_read(fileindex, index);
925 	fclose(index);
926 	if (err)
927 		goto done;
928 
929 	err = got_opentemp_named(&new_fileindex_path, &new_index,
930 	    fileindex_path);
931 	if (err)
932 		goto done;
933 
934 	err = got_object_open_as_commit(&commit, repo,
935 	   worktree->base_commit_id);
936 	if (err)
937 		goto done;
938 
939 	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
940 	if (err)
941 		goto done;
942 
943 	checkout_err = tree_checkout(worktree, fileindex, tree, "/", repo,
944 	    progress_cb, progress_arg, cancel_cb, cancel_arg);
945 
946 	/* Try to sync the fileindex back to disk in any case. */
947 	err = got_fileindex_write(fileindex, new_index);
948 	if (err)
949 		goto done;
950 
951 	if (rename(new_fileindex_path, fileindex_path) != 0) {
952 		err = got_error_from_errno();
953 		goto done;
954 	}
955 
956 	free(new_fileindex_path);
957 	new_fileindex_path = NULL;
958 
959 done:
960 	if (tree)
961 		got_object_tree_close(tree);
962 	if (commit)
963 		got_object_commit_close(commit);
964 	if (new_fileindex_path)
965 		unlink(new_fileindex_path);
966 	if (new_index)
967 		fclose(new_index);
968 	free(new_fileindex_path);
969 	free(fileindex_path);
970 	got_fileindex_free(fileindex);
971 	if (checkout_err)
972 		err = checkout_err;
973 	unlockerr = lock_worktree(worktree, LOCK_SH);
974 	if (unlockerr && err == NULL)
975 		err = unlockerr;
976 	return err;
977 }