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)->base, path_got, GOT_WORKTREE_BASE);
328 	if (err)
329 		goto done;
330 
331 	err = read_meta_file(&(*worktree)->head_ref, path_got,
332 	    GOT_WORKTREE_HEAD);
333 	if (err)
334 		goto done;
335 
336 done:
337 	free(path_got);
338 	free(path_lock);
339 	if (err) {
340 		if (fd != -1)
341 			close(fd);
342 		if (*worktree != NULL)
343 			got_worktree_close(*worktree);
344 		*worktree = NULL;
345 	} else
346 		(*worktree)->lockfd = fd;
347 
348 	return err;
349 }
350 
351 void
352 got_worktree_close(struct got_worktree *worktree)
353 {
354 	free(worktree->root_path);
355 	free(worktree->repo_path);
356 	free(worktree->path_prefix);
357 	free(worktree->base);
358 	free(worktree->head_ref);
359 	if (worktree->lockfd != -1)
360 		close(worktree->lockfd);
361 	free(worktree);
362 }
363 
364 char *
365 got_worktree_get_repo_path(struct got_worktree *worktree)
366 {
367 	return strdup(worktree->repo_path);
368 }
369 
370 char *
371 got_worktree_get_head_ref_name(struct got_worktree *worktree)
372 {
373 	return strdup(worktree->head_ref);
374 }
375 
376 static const struct got_error *
377 lock_worktree(struct got_worktree *worktree, int operation)
378 {
379 	if (flock(worktree->lockfd, operation | LOCK_NB) == -1)
380 		return (errno == EWOULDBLOCK ? got_error(GOT_ERR_WORKTREE_BUSY)
381 		    : got_error_from_errno());
382 	return NULL;
383 }
384 
385 static const char *
386 apply_path_prefix(struct got_worktree *worktree, const char *path)
387 {
388 	const char *p = path;
389 	p += strlen(worktree->path_prefix);
390 	if (*p == '/')
391 		p++;
392 	return p;
393 }
394 
395 static const struct got_error *
396 add_file_on_disk(struct got_worktree *worktree, struct got_fileindex *fileindex,
397    const char *path, struct got_blob_object *blob, struct got_repository *repo)
398 {
399 	const struct got_error *err = NULL;
400 	char *ondisk_path;
401 	int fd;
402 	size_t len, hdrlen;
403 	struct got_fileindex_entry *entry;
404 
405 	if (asprintf(&ondisk_path, "%s/%s", worktree->root_path,
406 	    apply_path_prefix(worktree, path)) == -1)
407 		return got_error_from_errno();
408 
409 	fd = open(ondisk_path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW,
410 	    GOT_DEFAULT_FILE_MODE);
411 	if (fd == -1) {
412 		err = got_error_from_errno();
413 		if (errno == EEXIST) {
414 			struct stat sb;
415 			if (lstat(ondisk_path, &sb) == -1) {
416 				err = got_error_from_errno();
417 			} else if (!S_ISREG(sb.st_mode)) {
418 				/* TODO file is obstructed; do something */
419 				err = got_error(GOT_ERR_FILE_OBSTRUCTED);
420 			}
421 		}
422 		return err;
423 	}
424 
425 	hdrlen = got_object_blob_get_hdrlen(blob);
426 	do {
427 		const uint8_t *buf = got_object_blob_get_read_buf(blob);
428 		err = got_object_blob_read_block(&len, blob);
429 		if (err)
430 			break;
431 		if (len > 0) {
432 			/* Skip blob object header first time around. */
433 			ssize_t outlen = write(fd, buf + hdrlen, len - hdrlen);
434 			if (outlen == -1) {
435 				err = got_error_from_errno();
436 				goto done;
437 			} else if (outlen != len - hdrlen) {
438 				err = got_error(GOT_ERR_IO);
439 				goto done;
440 			}
441 			hdrlen = 0;
442 		}
443 	} while (len != 0);
444 
445 	fsync(fd);
446 
447 	err = got_fileindex_entry_alloc(&entry, ondisk_path,
448 	    apply_path_prefix(worktree, path), blob->id.sha1);
449 	if (err)
450 		goto done;
451 
452 	err = got_fileindex_entry_add(fileindex, entry);
453 	if (err)
454 		goto done;
455 done:
456 	close(fd);
457 	free(ondisk_path);
458 	return err;
459 }
460 
461 static const struct got_error *
462 add_dir_on_disk(struct got_worktree *worktree, const char *path)
463 {
464 	const struct got_error *err = NULL;
465 	char *abspath;
466 
467 	if (asprintf(&abspath, "%s/%s", worktree->root_path,
468 	    apply_path_prefix(worktree, path)) == -1)
469 		return got_error_from_errno();
470 
471 	/* XXX queue work rather than editing disk directly? */
472 	if (mkdir(abspath, GOT_DEFAULT_DIR_MODE) == -1) {
473 		struct stat sb;
474 
475 		if (errno != EEXIST) {
476 			err = got_error_from_errno();
477 			goto done;
478 		}
479 
480 		if (lstat(abspath, &sb) == -1) {
481 			err = got_error_from_errno();
482 			goto done;
483 		}
484 
485 		if (!S_ISDIR(sb.st_mode)) {
486 			/* TODO directory is obstructed; do something */
487 			return got_error(GOT_ERR_FILE_OBSTRUCTED);
488 		}
489 	}
490 
491 done:
492 	free(abspath);
493 	return err;
494 }
495 
496 static const struct got_error *
497 tree_checkout(struct got_worktree *, struct got_fileindex *,
498     struct got_tree_object *, const char *, struct got_repository *,
499     got_worktree_checkout_cb progress_cb, void *progress_arg,
500     got_worktree_cancel_cb cancel_cb, void *cancel_arg);
501 
502 static const struct got_error *
503 tree_checkout_entry(struct got_worktree *worktree,
504     struct got_fileindex *fileindex, struct got_tree_entry *te,
505     const char *parent, struct got_repository *repo,
506     got_worktree_checkout_cb progress_cb, void *progress_arg,
507     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
508 {
509 	const struct got_error *err = NULL;
510 	struct got_object *obj = NULL;
511 	struct got_blob_object *blob = NULL;
512 	struct got_tree_object *tree = NULL;
513 	char *path = NULL;
514 	char *progress_path = NULL;
515 	size_t len;
516 
517 	if (parent[0] == '/' && parent[1] == '\0')
518 		parent = "";
519 	if (asprintf(&path, "%s/%s", parent, te->name) == -1)
520 		return got_error_from_errno();
521 
522 	/* Skip this entry if it is outside of our path prefix. */
523 	len = MIN(strlen(worktree->path_prefix), strlen(path));
524 	if (strncmp(path, worktree->path_prefix, len) != 0) {
525 		free(path);
526 		return NULL;
527 	}
528 
529 	err = got_object_open(&obj, repo, te->id);
530 	if (err)
531 		goto done;
532 
533 	progress_path = path;
534 	if (strncmp(progress_path, worktree->path_prefix, len) == 0)
535 		progress_path += len;
536 	(*progress_cb)(progress_arg, progress_path);
537 
538 	switch (obj->type) {
539 	case GOT_OBJ_TYPE_BLOB:
540 		if (strlen(worktree->path_prefix) >= strlen(path))
541 			break;
542 		err = got_object_blob_open(&blob, repo, obj, 8192);
543 		if (err)
544 			goto done;
545 		err = add_file_on_disk(worktree, fileindex, path, blob, repo);
546 		break;
547 	case GOT_OBJ_TYPE_TREE:
548 		err = got_object_tree_open(&tree, repo, obj);
549 		if (err)
550 			goto done;
551 		if (strlen(worktree->path_prefix) < strlen(path)) {
552 			err = add_dir_on_disk(worktree, path);
553 			if (err)
554 				break;
555 		}
556 		/* XXX infinite recursion possible */
557 		err = tree_checkout(worktree, fileindex, tree, path, repo,
558 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
559 		break;
560 	default:
561 		break;
562 	}
563 
564 done:
565 	if (blob)
566 		got_object_blob_close(blob);
567 	if (tree)
568 		got_object_tree_close(tree);
569 	if (obj)
570 		got_object_close(obj);
571 	free(path);
572 	return err;
573 }
574 
575 static const struct got_error *
576 tree_checkout(struct got_worktree *worktree,
577     struct got_fileindex *fileindex, struct got_tree_object *tree,
578     const char *path, struct got_repository *repo,
579     got_worktree_checkout_cb progress_cb, void *progress_arg,
580     got_worktree_cancel_cb cancel_cb, void *cancel_arg)
581 {
582 	const struct got_error *err = NULL;
583 	const struct got_tree_entries *entries;
584 	struct got_tree_entry *te;
585 	size_t len;
586 
587 	/* Skip this tree if it is outside of our path prefix. */
588 	len = MIN(strlen(worktree->path_prefix), strlen(path));
589 	if (strncmp(path, worktree->path_prefix, len) != 0)
590 		return NULL;
591 
592 	entries = got_object_tree_get_entries(tree);
593 	SIMPLEQ_FOREACH(te, &entries->head, entry) {
594 		if (cancel_cb) {
595 			err = (*cancel_cb)(cancel_arg);
596 			if (err)
597 				break;
598 		}
599 		err = tree_checkout_entry(worktree, fileindex, te, path, repo,
600 		    progress_cb, progress_arg, cancel_cb, cancel_arg);
601 		if (err)
602 			break;
603 	}
604 
605 	return err;
606 }
607 
608 const struct got_error *
609 got_worktree_checkout_files(struct got_worktree *worktree,
610     struct got_repository *repo, got_worktree_checkout_cb progress_cb,
611     void *progress_arg, got_worktree_cancel_cb cancel_cb, void *cancel_arg)
612 {
613 	const struct got_error *err = NULL, *unlockerr;
614 	struct got_object_id *commit_id = NULL;
615 	struct got_commit_object *commit = NULL;
616 	struct got_tree_object *tree = NULL;
617 	char *fileindex_path = NULL, *new_fileindex_path = NULL;
618 	struct got_fileindex *fileindex = NULL;
619 	FILE *new_index = NULL;
620 
621 	err = lock_worktree(worktree, LOCK_EX);
622 	if (err)
623 		return err;
624 
625 	err = got_object_resolve_id_str(&commit_id, repo, worktree->base);
626 	if (err)
627 		goto done;
628 
629 	fileindex = got_fileindex_alloc();
630 	if (fileindex == NULL) {
631 		err = got_error_from_errno();
632 		goto done;
633 	}
634 
635 	if (asprintf(&fileindex_path, "%s/%s/%s", worktree->root_path,
636 	    GOT_WORKTREE_GOT_DIR, GOT_WORKTREE_FILE_INDEX) == -1) {
637 		err = got_error_from_errno();
638 		fileindex_path = NULL;
639 		goto done;
640 	}
641 
642 	err = got_opentemp_named(&new_fileindex_path, &new_index,
643 	    fileindex_path);
644 	if (err)
645 		goto done;
646 
647 	err = got_object_open_as_commit(&commit, repo, commit_id);
648 	if (err)
649 		goto done;
650 
651 	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
652 	if (err)
653 		goto done;
654 
655 	err = tree_checkout(worktree, fileindex, tree, "/", repo,
656 	    progress_cb, progress_arg, cancel_cb, cancel_arg);
657 	if (err)
658 		goto done;
659 
660 	err = got_fileindex_write(fileindex, new_index);
661 	if (err)
662 		goto done;
663 
664 	if (rename(new_fileindex_path, fileindex_path) != 0) {
665 		err = got_error_from_errno();
666 		goto done;
667 	}
668 
669 	free(new_fileindex_path);
670 	new_fileindex_path = NULL;
671 
672 done:
673 	if (tree)
674 		got_object_tree_close(tree);
675 	if (commit)
676 		got_object_commit_close(commit);
677 	free(commit_id);
678 	if (new_fileindex_path)
679 		unlink(new_fileindex_path);
680 	if (new_index)
681 		fclose(new_index);
682 	free(new_fileindex_path);
683 	free(fileindex_path);
684 	got_fileindex_free(fileindex);
685 	unlockerr = lock_worktree(worktree, LOCK_SH);
686 	if (unlockerr && err == NULL)
687 		err = unlockerr;
688 	return err;
689 }