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 
31 #include "got_error.h"
32 #include "got_repository.h"
33 #include "got_reference.h"
34 #include "got_object.h"
35 #include "got_worktree.h"
36 #include "got_opentemp.h"
37 
38 #include "got_lib_worktree.h"
39 #include "got_lib_path.h"
40 #include "got_lib_sha1.h"
41 #include "got_lib_fileindex.h"
42 #include "got_lib_inflate.h"
43 #include "got_lib_delta.h"
44 #include "got_lib_object.h"
45 
46 #ifndef MIN
47 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
48 #endif
49 
50 static const struct got_error *
51 create_meta_file(const char *path_got, const char *name, const char *content)
52 {
53 	const struct got_error *err = NULL;
54 	char *path;
55 	int fd = -1;
56 	char buf[4];
57 	ssize_t n;
58 
59 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
60 		err = got_error_from_errno();
61 		path = NULL;
62 		goto done;
63 	}
64 
65 	fd = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
66 	    GOT_DEFAULT_FILE_MODE);
67 	if (fd == -1) {
68 		err = got_error_from_errno();
69 		goto done;
70 	}
71 
72 	/* The file should be empty. */
73 	n = read(fd, buf, sizeof(buf));
74 	if (n != 0) {
75 		err = (n == -1 ? got_error_from_errno() :
76 		    got_error(GOT_ERR_WORKTREE_EXISTS));
77 		goto done;
78 	}
79 
80 	if (content) {
81 		int len = dprintf(fd, "%s\n", content);
82 		if (len != strlen(content) + 1) {
83 			err = got_error_from_errno();
84 			goto done;
85 		}
86 	}
87 
88 done:
89 	if (fd != -1 && close(fd) == -1 && err == NULL)
90 		err = got_error_from_errno();
91 	free(path);
92 	return err;
93 }
94 
95 static const struct got_error *
96 read_meta_file(char **content, const char *path_got, const char *name)
97 {
98 	const struct got_error *err = NULL;
99 	char *path;
100 	int fd = -1;
101 	ssize_t n;
102 	struct stat sb;
103 
104 	*content = NULL;
105 
106 	if (asprintf(&path, "%s/%s", path_got, name) == -1) {
107 		err = got_error_from_errno();
108 		path = NULL;
109 		goto done;
110 	}
111 
112 	fd = open(path, O_RDONLY | O_NOFOLLOW);
113 	if (fd == -1) {
114 		err = got_error_from_errno();
115 		goto done;
116 	}
117 	if (flock(fd, LOCK_SH | LOCK_NB) == -1) {
118 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
119 		    : got_error_from_errno());
120 		goto done;
121 	}
122 
123 	stat(path, &sb);
124 	*content = calloc(1, sb.st_size);
125 	if (*content == NULL) {
126 		err = got_error_from_errno();
127 		goto done;
128 	}
129 
130 	n = read(fd, *content, sb.st_size);
131 	if (n != sb.st_size) {
132 		err = (n == -1 ? got_error_from_errno() :
133 		    got_error(GOT_ERR_WORKTREE_META));
134 		goto done;
135 	}
136 	if ((*content)[sb.st_size - 1] != '\n') {
137 		err = got_error(GOT_ERR_WORKTREE_META);
138 		goto done;
139 	}
140 	(*content)[sb.st_size - 1] = '\0';
141 
142 done:
143 	if (fd != -1 && close(fd) == -1 && err == NULL)
144 		err = got_error_from_errno();
145 	free(path);
146 	if (err) {
147 		free(*content);
148 		*content = NULL;
149 	}
150 	return err;
151 }
152 
153 const struct got_error *
154 got_worktree_init(const char *path, struct got_reference *head_ref,
155     const char *prefix, struct got_repository *repo)
156 {
157 	const struct got_error *err = NULL;
158 	struct got_object_id *commit_id = NULL;
159 	int obj_type;
160 	char *path_got = NULL;
161 	char *refstr = NULL;
162 	char *repo_path = NULL;
163 	char *formatstr = NULL;
164 	char *absprefix = NULL;
165 	char *basestr = NULL;
166 
167 	err = got_ref_resolve(&commit_id, repo, head_ref);
168 	if (err)
169 		return err;
170 	err = got_object_get_type(&obj_type, repo, commit_id);
171 	if (err)
172 		return err;
173 	if (obj_type != GOT_OBJ_TYPE_COMMIT)
174 		return got_error(GOT_ERR_OBJ_TYPE);
175 
176 	if (!got_path_is_absolute(prefix)) {
177 		if (asprintf(&absprefix, "/%s", prefix) == -1)
178 			return got_error_from_errno();
179 	}
180 
181 	/* Create top-level directory (may already exist). */
182 	if (mkdir(path, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
183 		err = got_error_from_errno();
184 		goto done;
185 	}
186 
187 	/* Create .got directory (may already exist). */
188 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
189 		err = got_error_from_errno();
190 		goto done;
191 	}
192 	if (mkdir(path_got, GOT_DEFAULT_DIR_MODE) == -1 && errno != EEXIST) {
193 		err = got_error_from_errno();
194 		goto done;
195 	}
196 
197 	/* Create an empty lock file. */
198 	err = create_meta_file(path_got, GOT_WORKTREE_LOCK, NULL);
199 	if (err)
200 		goto done;
201 
202 	/* Create an empty file index. */
203 	err = create_meta_file(path_got, GOT_WORKTREE_FILE_INDEX, NULL);
204 	if (err)
205 		goto done;
206 
207 	/* Write the HEAD reference. */
208 	refstr = got_ref_to_str(head_ref);
209 	if (refstr == NULL) {
210 		err = got_error_from_errno();
211 		goto done;
212 	}
213 	err = create_meta_file(path_got, GOT_WORKTREE_HEAD, refstr);
214 	if (err)
215 		goto done;
216 
217 	/* Record our base commit. */
218 	err = got_object_id_str(&basestr, commit_id);
219 	if (err)
220 		goto done;
221 	err = create_meta_file(path_got, GOT_WORKTREE_BASE, basestr);
222 	if (err)
223 		goto done;
224 
225 	/* Store path to repository. */
226 	repo_path = got_repo_get_path(repo);
227 	if (repo_path == NULL) {
228 		err = got_error_from_errno();
229 		goto done;
230 	}
231 	err = create_meta_file(path_got, GOT_WORKTREE_REPOSITORY, repo_path);
232 	if (err)
233 		goto done;
234 
235 	/* Store in-repository path prefix. */
236 	err = create_meta_file(path_got, GOT_WORKTREE_PATH_PREFIX,
237 	    absprefix ? absprefix : prefix);
238 	if (err)
239 		goto done;
240 
241 	/* Stamp work tree with format file. */
242 	if (asprintf(&formatstr, "%d", GOT_WORKTREE_FORMAT_VERSION) == -1) {
243 		err = got_error_from_errno();
244 		goto done;
245 	}
246 	err = create_meta_file(path_got, GOT_WORKTREE_FORMAT, formatstr);
247 	if (err)
248 		goto done;
249 
250 done:
251 	free(commit_id);
252 	free(path_got);
253 	free(formatstr);
254 	free(refstr);
255 	free(repo_path);
256 	free(absprefix);
257 	free(basestr);
258 	return err;
259 }
260 
261 const struct got_error *
262 got_worktree_open(struct got_worktree **worktree, const char *path)
263 {
264 	const struct got_error *err = NULL;
265 	char *path_got;
266 	char *formatstr = NULL;
267 	char *path_lock = NULL;
268 	int version, fd = -1;
269 	const char *errstr;
270 
271 	*worktree = NULL;
272 
273 	if (asprintf(&path_got, "%s/%s", path, GOT_WORKTREE_GOT_DIR) == -1) {
274 		err = got_error_from_errno();
275 		path_got = NULL;
276 		goto done;
277 	}
278 
279 	if (asprintf(&path_lock, "%s/%s", path_got, GOT_WORKTREE_LOCK) == -1) {
280 		err = got_error_from_errno();
281 		path_lock = NULL;
282 		goto done;
283 	}
284 
285 	fd = open(path_lock, O_RDWR | O_EXLOCK | O_NONBLOCK);
286 	if (fd == -1) {
287 		err = (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
288 		    : got_error_from_errno());
289 		goto done;
290 	}
291 
292 	err = read_meta_file(&formatstr, path_got, GOT_WORKTREE_FORMAT);
293 	if (err)
294 		goto done;
295 
296 	version = strtonum(formatstr, 1, INT_MAX, &errstr);
297 	if (errstr) {
298 		err = got_error(GOT_ERR_WORKTREE_META);
299 		goto done;
300 	}
301 	if (version != GOT_WORKTREE_FORMAT_VERSION) {
302 		err = got_error(GOT_ERR_WORKTREE_VERS);
303 		goto done;
304 	}
305 
306 	*worktree = calloc(1, sizeof(**worktree));
307 	if (*worktree == NULL) {
308 		err = got_error_from_errno();
309 		goto done;
310 	}
311 	(*worktree)->lockfd = -1;
312 
313 	(*worktree)->root_path = strdup(path);
314 	if ((*worktree)->root_path == NULL) {
315 		err = got_error_from_errno();
316 		goto done;
317 	}
318 	err = read_meta_file(&(*worktree)->repo_path, path_got,
319 	    GOT_WORKTREE_REPOSITORY);
320 	if (err)
321 		goto done;
322 	err = read_meta_file(&(*worktree)->path_prefix, path_got,
323 	    GOT_WORKTREE_PATH_PREFIX);
324 	if (err)
325 		goto done;
326 
327 	err = read_meta_file(&(*worktree)->head_ref, path_got,
328 	    GOT_WORKTREE_HEAD);
329 	if (err)
330 		goto done;
331 
332 done:
333 	free(path_got);
334 	free(path_lock);
335 	if (err) {
336 		if (fd != -1)
337 			close(fd);
338 		if (*worktree != NULL)
339 			got_worktree_close(*worktree);
340 		*worktree = NULL;
341 	} else
342 		(*worktree)->lockfd = fd;
343 
344 	return err;
345 }
346 
347 void
348 got_worktree_close(struct got_worktree *worktree)
349 {
350 	free(worktree->root_path);
351 	free(worktree->repo_path);
352 	free(worktree->path_prefix);
353 	free(worktree->base_commit);
354 	free(worktree->head_ref);
355 	if (worktree->lockfd != -1)
356 		close(worktree->lockfd);
357 	free(worktree);
358 }
359 
360 char *
361 got_worktree_get_repo_path(struct got_worktree *worktree)
362 {
363 	return strdup(worktree->repo_path);
364 }
365 
366 char *
367 got_worktree_get_head_ref_name(struct got_worktree *worktree)
368 {
369 	return strdup(worktree->head_ref);
370 }
371 
372 static const struct got_error *
373 lock_worktree(struct got_worktree *worktree, int operation)
374 {
375 	if (flock(worktree->lockfd, operation | LOCK_NB) == -1)
376 		return (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
377 		    : got_error_from_errno());
378 	return NULL;
379 }
380 
381 static const char *
382 apply_path_prefix(struct got_worktree *worktree, const char *path)
383 {
384 	const char *p = path;
385 	p += strlen(worktree->path_prefix);
386 	if (*p == '/')
387 		p++;
388 	return p;
389 }
390 
391 static const struct got_error *
392 add_file_on_disk(struct got_worktree *worktree, struct got_fileindex *fileindex,
393    const char *path, struct got_blob_object *blob, struct got_repository *repo)
394 {
395 	const struct got_error *err = NULL;
396 	char *ondisk_path;
397 	int fd;
398 	size_t len, hdrlen;
399 	struct got_fileindex_entry *entry;
400 
401 	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path,
402 	    apply_path_prefix(worktree, path)) == -1)
403 		return got_error_from_errno();
404 
405 	fd = open(ondisk_path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
406 	    GOT_DEFAULT_FILE_MODE);
407 	if (fd == -1) {
408 		err = got_error_from_errno();
409 		if (errno == EEXIST) {
410 			struct stat sb;
411 			if (lstat(ondisk_path, &sb) == -1) {
412 				err = got_error_from_errno();
413 			} else if (!S_ISREG(sb.st_mode)) {
414 				/* TODO file is obstructed; do something */
415 				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
416 			}
417 		}
418 		return err;
419 	}
420 
421 	hdrlen = got_object_blob_get_hdrlen(blob);
422 	do {
423 		const uint8_t *buf = got_object_blob_get_read_buf(blob);
424 		err = got_object_blob_read_block(&len, blob);
425 		if (err)
426 			break;
427 		if (len > 0) {
428 			/* Skip blob object header first time around. */
429 			ssize_t outlen = write(fd, buf + hdrlen, len - hdrlen);
430 			if (outlen == -1) {
431 				err = got_error_from_errno();
432 				goto done;
433 			} else if (outlen != len - hdrlen) {
434 				err = got_error(GOT_ERR_IO);
435 				goto done;
436 			}
437 			hdrlen = 0;
438 		}
439 	} while (len != 0);
440 
441 	fsync(fd);
442 
443 	err = got_fileindex_entry_alloc(&entry, ondisk_path,
444 	    apply_path_prefix(worktree, path), blob->id.sha1);
445 	if (err)
446 		goto done;
447 
448 	err = got_fileindex_entry_add(fileindex, entry);
449 	if (err)
450 		goto done;
451 done:
452 	close(fd);
453 	free(ondisk_path);
454 	return err;
455 }
456 
457 static const struct got_error *
458 add_dir_on_disk(struct got_worktree *worktree, const char *path)
459 {
460 	const struct got_error *err = NULL;
461 	char *abspath;
462 
463 	if (asprintf(&abspath, "%s/%s", worktree->root_path,
464 	    apply_path_prefix(worktree, path)) == -1)
465 		return got_error_from_errno();
466 
467 	/* XXX queue work rather than editing disk directly? */
468 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
469 		struct stat sb;
470 
471 		if (errno != EEXIST) {
472 			err = got_error_from_errno();
473 			goto done;
474 		}
475 
476 		if (lstat(abspath, &sb) == -1) {
477 			err = got_error_from_errno();
478 			goto done;
479 		}
480 
481 		if (!S_ISDIR(sb.st_mode)) {
482 			/* TODO directory is obstructed; do something */
483 			return got_error(GOT_ERR_FILE_OBSTRUCTED);
484 		}
485 	}
486 
487 done:
488 	free(abspath);
489 	return err;
490 }
491 
492 static const struct got_error *
493 tree_checkout(struct got_worktree *, struct got_fileindex *,
494     struct got_tree_object *, const char *, struct got_repository *,
495     got_worktree_checkout_cb progress_cb, void *progress_arg,
496     got_worktree_cancel_cb cancel_cb, void *cancel_arg);
497 
498 static const struct got_error *
499 tree_checkout_entry(struct got_worktree *worktree,
500     struct got_fileindex *fileindex, struct got_tree_entry *te,
501     const char *parent, struct got_repository *repo,
502     got_worktree_checkout_cb progress_cb, void *progress_arg,
503     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
504 {
505 	const struct got_error *err = NULL;
506 	struct got_object *obj = NULL;
507 	struct got_blob_object *blob = NULL;
508 	struct got_tree_object *tree = NULL;
509 	char *path = NULL;
510 	char *progress_path = NULL;
511 	size_t len;
512 
513 	if (parent[0] == '/' && parent[1] == '\0')
514 		parent = "";
515 	if (asprintf(&path, "%s/%s", parent, te->name) == -1)
516 		return got_error_from_errno();
517 
518 	/* Skip this entry if it is outside of our path prefix. */
519 	len = MIN(strlen(worktree->path_prefix), strlen(path));
520 	if (strncmp(path, worktree->path_prefix, len) != 0) {
521 		free(path);
522 		return NULL;
523 	}
524 
525 	err = got_object_open(&obj, repo, te->id);
526 	if (err)
527 		goto done;
528 
529 	progress_path = path;
530 	if (strncmp(progress_path, worktree->path_prefix, len) == 0)
531 		progress_path += len;
532 	(*progress_cb)(progress_arg, progress_path);
533 
534 	switch (obj->type) {
535 	case GOT_OBJ_TYPE_BLOB:
536 		if (strlen(worktree->path_prefix) >= strlen(path))
537 			break;
538 		err = got_object_blob_open(&blob, repo, obj, 8192);
539 		if (err)
540 			goto done;
541 		err = add_file_on_disk(worktree, fileindex, path, blob, repo);
542 		break;
543 	case GOT_OBJ_TYPE_TREE:
544 		err = got_object_tree_open(&tree, repo, obj);
545 		if (err)
546 			goto done;
547 		if (strlen(worktree->path_prefix) < strlen(path)) {
548 			err = add_dir_on_disk(worktree, path);
549 			if (err)
550 				break;
551 		}
552 		/* XXX infinite recursion possible */
553 		err = tree_checkout(worktree, fileindex, tree, path, repo,
554 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
555 		break;
556 	default:
557 		break;
558 	}
559 
560 done:
561 	if (blob)
562 		got_object_blob_close(blob);
563 	if (tree)
564 		got_object_tree_close(tree);
565 	if (obj)
566 		got_object_close(obj);
567 	free(path);
568 	return err;
569 }
570 
571 static const struct got_error *
572 tree_checkout(struct got_worktree *worktree,
573     struct got_fileindex *fileindex, struct got_tree_object *tree,
574     const char *path, struct got_repository *repo,
575     got_worktree_checkout_cb progress_cb, void *progress_arg,
576     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
577 {
578 	const struct got_error *err = NULL;
579 	const struct got_tree_entries *entries;
580 	struct got_tree_entry *te;
581 	size_t len;
582 
583 	/* Skip this tree if it is outside of our path prefix. */
584 	len = MIN(strlen(worktree->path_prefix), strlen(path));
585 	if (strncmp(path, worktree->path_prefix, len) != 0)
586 		return NULL;
587 
588 	entries = got_object_tree_get_entries(tree);
589 	SIMPLEQ_FOREACH(te, &entries->head, entry) {
590 		if (cancel_cb) {
591 			err = (*cancel_cb)(cancel_arg);
592 			if (err)
593 				break;
594 		}
595 		err = tree_checkout_entry(worktree, fileindex, te, path, repo,
596 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
597 		if (err)
598 			break;
599 	}
600 
601 	return err;
602 }
603 
604 const struct got_error *
605 got_worktree_checkout_files(struct got_worktree *worktree,
606     struct got_reference *head_ref, struct got_repository *repo,
607     got_worktree_checkout_cb progress_cb, void *progress_arg,
608     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
609 {
610 	const struct got_error *err = NULL, *unlockerr;
611 	struct got_object_id *commit_id = NULL;
612 	struct got_object *obj = NULL;
613 	struct got_commit_object *commit = NULL;
614 	struct got_tree_object *tree = NULL;
615 	char *fileindex_path = NULL, *new_fileindex_path = NULL;
616 	struct got_fileindex *fileindex = NULL;
617 	FILE *new_index = NULL;
618 
619 	err = lock_worktree(worktree, LOCK_EX);
620 	if (err)
621 		return err;
622 
623 	fileindex = got_fileindex_alloc();
624 	if (fileindex == NULL) {
625 		err = got_error_from_errno();
626 		goto done;
627 	}
628 
629 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
630 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
631 		err = got_error_from_errno();
632 		fileindex_path = NULL;
633 		goto done;
634 	}
635 
636 	err = got_opentemp_named(&new_fileindex_path, &new_index,
637 	    fileindex_path);
638 	if (err)
639 		goto done;
640 
641 	err = got_ref_resolve(&commit_id, repo, head_ref);
642 	if (err)
643 		goto done;
644 
645 	err = got_object_open(&obj, repo, commit_id);
646 	if (err)
647 		goto done;
648 
649 	if (obj->type != GOT_OBJ_TYPE_COMMIT) {
650 		err = got_error(GOT_ERR_OBJ_TYPE);
651 		goto done;
652 	}
653 
654 	err = got_object_commit_open(&commit, repo, obj);
655 	if (err)
656 		goto done;
657 
658 	got_object_close(obj);
659 	err = got_object_open(&obj, repo, commit->tree_id);
660 	if (err)
661 		goto done;
662 
663 	if (obj->type != GOT_OBJ_TYPE_TREE) {
664 		err = got_error(GOT_ERR_OBJ_TYPE);
665 		goto done;
666 	}
667 
668 	err = got_object_tree_open(&tree, repo, obj);
669 	if (err)
670 		goto done;
671 
672 	err = tree_checkout(worktree, fileindex, tree, "/", repo,
673 	    progress_cb, progress_arg, cancel_cb, cancel_arg);
674 	if (err)
675 		goto done;
676 
677 	err = got_fileindex_write(fileindex, new_index);
678 	if (err)
679 		goto done;
680 
681 	if (rename(new_fileindex_path, fileindex_path) != 0) {
682 		err = got_error_from_errno();
683 		goto done;
684 	}
685 
686 	free(new_fileindex_path);
687 	new_fileindex_path = NULL;
688 
689 done:
690 	if (tree)
691 		got_object_tree_close(tree);
692 	if (commit)
693 		got_object_commit_close(commit);
694 	if (obj)
695 		got_object_close(obj);
696 	free(commit_id);
697 	if (new_fileindex_path)
698 		unlink(new_fileindex_path);
699 	if (new_index)
700 		fclose(new_index);
701 	free(new_fileindex_path);
702 	free(fileindex_path);
703 	got_fileindex_free(fileindex);
704 	unlockerr = lock_worktree(worktree, LOCK_SH);
705 	if (unlockerr && err == NULL)
706 		err = unlockerr;
707 	return err;
708 }