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