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Date:: Thu Jul 11 10:57:15 2019 UTC
Message:: new realpath(3) doesn't like receiving an empty path as input
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1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/queue.h>
19 #include <sys/uio.h>
20 #include <sys/stat.h>
21 #include <sys/mman.h>
22 #include <sys/syslimits.h>
23 
24 #include <ctype.h>
25 #include <fcntl.h>
26 #include <limits.h>
27 #include <dirent.h>
28 #include <stdlib.h>
29 #include <stdio.h>
30 #include <sha1.h>
31 #include <string.h>
32 #include <zlib.h>
33 #include <errno.h>
34 #include <libgen.h>
35 #include <stdint.h>
36 #include <imsg.h>
37 #include <uuid.h>
38 
39 #include "got_error.h"
40 #include "got_reference.h"
41 #include "got_repository.h"
42 #include "got_path.h"
43 #include "got_worktree.h"
44 #include "got_object.h"
45 
46 #include "got_lib_delta.h"
47 #include "got_lib_inflate.h"
48 #include "got_lib_object.h"
49 #include "got_lib_pack.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_worktree.h"
52 #include "got_lib_sha1.h"
53 #include "got_lib_object_cache.h"
54 #include "got_lib_repository.h"
55 
56 #ifndef nitems
57 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
58 #endif
59 
60 #define GOT_GIT_DIR	".git"
61 
62 /* Mandatory files and directories inside the git directory. */
63 #define GOT_OBJECTS_DIR		"objects"
64 #define GOT_REFS_DIR		"refs"
65 #define GOT_HEAD_FILE		"HEAD"
66 
67 /* Other files and directories inside the git directory. */
68 #define GOT_FETCH_HEAD_FILE	"FETCH_HEAD"
69 #define GOT_ORIG_HEAD_FILE	"ORIG_HEAD"
70 #define GOT_OBJECTS_PACK_DIR	"objects/pack"
71 #define GOT_PACKED_REFS_FILE	"packed-refs"
72 
73 const char *
74 got_repo_get_path(struct got_repository *repo)
75 {
76 	return repo->path;
77 }
78 
79 const char *
80 got_repo_get_path_git_dir(struct got_repository *repo)
81 {
82 	return repo->path_git_dir;
83 }
84 
85 int
86 got_repo_is_bare(struct got_repository *repo)
87 {
88 	return (strcmp(repo->path, repo->path_git_dir) == 0);
89 }
90 
91 static char *
92 get_path_git_child(struct got_repository *repo, const char *basename)
93 {
94 	char *path_child;
95 	
96 	if (asprintf(&path_child, "%s/%s", repo->path_git_dir,
97 	    basename) == -1)
98 		return NULL;
99 
100 	return path_child;
101 }
102 
103 char *
104 got_repo_get_path_objects(struct got_repository *repo)
105 {
106 	return get_path_git_child(repo, GOT_OBJECTS_DIR);
107 }
108 
109 char *
110 got_repo_get_path_objects_pack(struct got_repository *repo)
111 {
112 	return get_path_git_child(repo, GOT_OBJECTS_PACK_DIR);
113 }
114 
115 char *
116 got_repo_get_path_refs(struct got_repository *repo)
117 {
118 	return get_path_git_child(repo, GOT_REFS_DIR);
119 }
120 
121 char *
122 got_repo_get_path_packed_refs(struct got_repository *repo)
123 {
124 	return get_path_git_child(repo, GOT_PACKED_REFS_FILE);
125 }
126 
127 static char *
128 get_path_head(struct got_repository *repo)
129 {
130 	return get_path_git_child(repo, GOT_HEAD_FILE);
131 }
132 
133 static int
134 is_git_repo(struct got_repository *repo)
135 {
136 	const char *path_git = got_repo_get_path_git_dir(repo);
137 	char *path_objects = got_repo_get_path_objects(repo);
138 	char *path_refs = got_repo_get_path_refs(repo);
139 	char *path_head = get_path_head(repo);
140 	int ret = 0;
141 	struct stat sb;
142 	struct got_reference *head_ref;
143 
144 	if (lstat(path_git, &sb) == -1)
145 		goto done;
146 	if (!S_ISDIR(sb.st_mode))
147 		goto done;
148 
149 	if (lstat(path_objects, &sb) == -1)
150 		goto done;
151 	if (!S_ISDIR(sb.st_mode))
152 		goto done;
153 
154 	if (lstat(path_refs, &sb) == -1)
155 		goto done;
156 	if (!S_ISDIR(sb.st_mode))
157 		goto done;
158 
159 	if (lstat(path_head, &sb) == -1)
160 		goto done;
161 	if (!S_ISREG(sb.st_mode))
162 		goto done;
163 
164 	/* Check if the HEAD reference can be opened. */
165 	if (got_ref_open(&head_ref, repo, GOT_REF_HEAD, 0) != NULL)
166 		goto done;
167 	got_ref_close(head_ref);
168 
169 	ret = 1;
170 done:
171 	free(path_objects);
172 	free(path_refs);
173 	free(path_head);
174 	return ret;
175 
176 }
177 
178 const struct got_error *
179 got_repo_cache_object(struct got_repository *repo, struct got_object_id *id,
180     struct got_object *obj)
181 {
182 #ifndef GOT_NO_OBJ_CACHE
183 	const struct got_error *err = NULL;
184 	err = got_object_cache_add(&repo->objcache, id, obj);
185 	if (err) {
186 		if (err->code == GOT_ERR_OBJ_EXISTS ||
187 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
188 			err = NULL;
189 		return err;
190 	}
191 	obj->refcnt++;
192 #endif
193 	return NULL;
194 }
195 
196 struct got_object *
197 got_repo_get_cached_object(struct got_repository *repo,
198     struct got_object_id *id)
199 {
200 	return (struct got_object *)got_object_cache_get(&repo->objcache, id);
201 }
202 
203 const struct got_error *
204 got_repo_cache_tree(struct got_repository *repo, struct got_object_id *id,
205     struct got_tree_object *tree)
206 {
207 #ifndef GOT_NO_OBJ_CACHE
208 	const struct got_error *err = NULL;
209 	err = got_object_cache_add(&repo->treecache, id, tree);
210 	if (err) {
211 		if (err->code == GOT_ERR_OBJ_EXISTS ||
212 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
213 			err = NULL;
214 		return err;
215 	}
216 	tree->refcnt++;
217 #endif
218 	return NULL;
219 }
220 
221 struct got_tree_object *
222 got_repo_get_cached_tree(struct got_repository *repo,
223     struct got_object_id *id)
224 {
225 	return (struct got_tree_object *)got_object_cache_get(
226 	    &repo->treecache, id);
227 }
228 
229 const struct got_error *
230 got_repo_cache_commit(struct got_repository *repo, struct got_object_id *id,
231     struct got_commit_object *commit)
232 {
233 #ifndef GOT_NO_OBJ_CACHE
234 	const struct got_error *err = NULL;
235 	err = got_object_cache_add(&repo->commitcache, id, commit);
236 	if (err) {
237 		if (err->code == GOT_ERR_OBJ_EXISTS ||
238 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
239 			err = NULL;
240 		return err;
241 	}
242 	commit->refcnt++;
243 #endif
244 	return NULL;
245 }
246 
247 struct got_commit_object *
248 got_repo_get_cached_commit(struct got_repository *repo,
249     struct got_object_id *id)
250 {
251 	return (struct got_commit_object *)got_object_cache_get(
252 	    &repo->commitcache, id);
253 }
254 
255 const struct got_error *
256 got_repo_cache_tag(struct got_repository *repo, struct got_object_id *id,
257     struct got_tag_object *tag)
258 {
259 #ifndef GOT_NO_OBJ_CACHE
260 	const struct got_error *err = NULL;
261 	err = got_object_cache_add(&repo->tagcache, id, tag);
262 	if (err) {
263 		if (err->code == GOT_ERR_OBJ_EXISTS ||
264 		    err->code == GOT_ERR_OBJ_TOO_LARGE)
265 			err = NULL;
266 		return err;
267 	}
268 	tag->refcnt++;
269 #endif
270 	return NULL;
271 }
272 
273 struct got_tag_object *
274 got_repo_get_cached_tag(struct got_repository *repo, struct got_object_id *id)
275 {
276 	return (struct got_tag_object *)got_object_cache_get(
277 	    &repo->tagcache, id);
278 }
279 
280 const struct got_error *
281 open_repo(struct got_repository *repo, const char *path)
282 {
283 	const struct got_error *err = NULL;
284 
285 	/* bare git repository? */
286 	repo->path_git_dir = strdup(path);
287 	if (repo->path_git_dir == NULL)
288 		return got_error_from_errno("strdup");
289 	if (is_git_repo(repo)) {
290 		repo->path = strdup(repo->path_git_dir);
291 		if (repo->path == NULL) {
292 			err = got_error_from_errno("strdup");
293 			goto done;
294 		}
295 		return NULL;
296 	}
297 
298 	/* git repository with working tree? */
299 	free(repo->path_git_dir);
300 	if (asprintf(&repo->path_git_dir, "%s/%s", path, GOT_GIT_DIR) == -1) {
301 		err = got_error_from_errno("asprintf");
302 		goto done;
303 	}
304 	if (is_git_repo(repo)) {
305 		repo->path = strdup(path);
306 		if (repo->path == NULL) {
307 			err = got_error_from_errno("strdup");
308 			goto done;
309 		}
310 		return NULL;
311 	}
312 
313 	err = got_error(GOT_ERR_NOT_GIT_REPO);
314 done:
315 	if (err) {
316 		free(repo->path);
317 		repo->path = NULL;
318 		free(repo->path_git_dir);
319 		repo->path_git_dir = NULL;
320 	}
321 	return err;
322 }
323 
324 const struct got_error *
325 got_repo_open(struct got_repository **repop, const char *path)
326 {
327 	struct got_repository *repo = NULL;
328 	const struct got_error *err = NULL;
329 	char *abspath, *normpath = NULL;
330 	int i, tried_root = 0;
331 
332 	*repop = NULL;
333 
334 	if (got_path_is_absolute(path))
335 		abspath = strdup(path);
336 	else
337 		abspath = got_path_get_absolute(path);
338 	if (abspath == NULL)
339 		return got_error(GOT_ERR_BAD_PATH);
340 
341 	repo = calloc(1, sizeof(*repo));
342 	if (repo == NULL) {
343 		err = got_error_from_errno("calloc");
344 		goto done;
345 	}
346 
347 	for (i = 0; i < nitems(repo->privsep_children); i++) {
348 		memset(&repo->privsep_children[i], 0,
349 		    sizeof(repo->privsep_children[0]));
350 		repo->privsep_children[i].imsg_fd = -1;
351 	}
352 
353 	err = got_object_cache_init(&repo->objcache,
354 	    GOT_OBJECT_CACHE_TYPE_OBJ);
355 	if (err)
356 		goto done;
357 	err = got_object_cache_init(&repo->treecache,
358 	    GOT_OBJECT_CACHE_TYPE_TREE);
359 	if (err)
360 		goto done;
361 	err = got_object_cache_init(&repo->commitcache,
362 	    GOT_OBJECT_CACHE_TYPE_COMMIT);
363 	if (err)
364 		goto done;
365 	err = got_object_cache_init(&repo->tagcache,
366 	    GOT_OBJECT_CACHE_TYPE_TAG);
367 	if (err)
368 		goto done;
369 
370 	normpath = got_path_normalize(abspath);
371 	if (normpath == NULL) {
372 		err = got_error(GOT_ERR_BAD_PATH);
373 		goto done;
374 	}
375 
376 	path = normpath;
377 	do {
378 		err = open_repo(repo, path);
379 		if (err == NULL)
380 			break;
381 		if (err->code != GOT_ERR_NOT_GIT_REPO)
382 			break;
383 		if (path[0] == '/' && path[1] == '\0') {
384 			if (tried_root) {
385 				err = got_error(GOT_ERR_NOT_GIT_REPO);
386 				break;
387 			}
388 			tried_root = 1;
389 		}
390 		path = dirname(path);
391 		if (path == NULL)
392 			err = got_error_from_errno2("dirname", path);
393 	} while (path);
394 done:
395 	if (err)
396 		got_repo_close(repo);
397 	else
398 		*repop = repo;
399 	free(abspath);
400 	free(normpath);
401 	return err;
402 }
403 
404 const struct got_error *
405 got_repo_close(struct got_repository *repo)
406 {
407 	const struct got_error *err = NULL, *child_err;
408 	int i;
409 
410 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
411 		if (repo->packidx_cache[i] == NULL)
412 			break;
413 		got_packidx_close(repo->packidx_cache[i]);
414 	}
415 
416 	for (i = 0; i < nitems(repo->packs); i++) {
417 		if (repo->packs[i].path_packfile == NULL)
418 			break;
419 		got_pack_close(&repo->packs[i]);
420 	}
421 
422 	free(repo->path);
423 	free(repo->path_git_dir);
424 
425 	got_object_cache_close(&repo->objcache);
426 	got_object_cache_close(&repo->treecache);
427 	got_object_cache_close(&repo->commitcache);
428 	got_object_cache_close(&repo->tagcache);
429 
430 	for (i = 0; i < nitems(repo->privsep_children); i++) {
431 		if (repo->privsep_children[i].imsg_fd == -1)
432 			continue;
433 		imsg_clear(repo->privsep_children[i].ibuf);
434 		free(repo->privsep_children[i].ibuf);
435 		err = got_privsep_send_stop(repo->privsep_children[i].imsg_fd);
436 		child_err = got_privsep_wait_for_child(
437 		    repo->privsep_children[i].pid);
438 		if (child_err && err == NULL)
439 			err = child_err;
440 		if (close(repo->privsep_children[i].imsg_fd) != 0 &&
441 		    err == NULL)
442 			err = got_error_from_errno("close");
443 	}
444 	free(repo);
445 
446 	return err;
447 }
448 
449 const struct got_error *
450 got_repo_map_path(char **in_repo_path, struct got_repository *repo,
451     const char *input_path, int check_disk)
452 {
453 	const struct got_error *err = NULL;
454 	const char *repo_abspath = NULL;
455 	size_t repolen, cwdlen, len;
456 	char *cwd, *canonpath, *path = NULL;
457 
458 	*in_repo_path = NULL;
459 
460 	cwd = getcwd(NULL, 0);
461 	if (cwd == NULL)
462 		return got_error_from_errno("getcwd");
463 
464 	canonpath = strdup(input_path);
465 	if (canonpath == NULL) {
466 		err = got_error_from_errno("strdup");
467 		goto done;
468 	}
469 	err = got_canonpath(input_path, canonpath, strlen(canonpath) + 1);
470 	if (err)
471 		goto done;
472 
473 	repo_abspath = got_repo_get_path(repo);
474 
475 	if (!check_disk || canonpath[0] == '\0') {
476 		path = strdup(canonpath);
477 		if (path == NULL) {
478 			err = got_error_from_errno("strdup");
479 			goto done;
480 		}
481 	} else {
482 		int is_repo_child = 0, is_cwd_child = 0;
483 
484 		path = realpath(canonpath, NULL);
485 		if (path == NULL) {
486 			if (errno != ENOENT) {
487 				err = got_error_from_errno2("realpath",
488 				    canonpath);
489 				goto done;
490 			}
491 			/*
492 			 * Path is not on disk.
493 			 * Assume it is already relative to repository root.
494 			 */
495 			path = strdup(canonpath);
496 			if (path == NULL) {
497 				err = got_error_from_errno("strdup");
498 				goto done;
499 			}
500 		}
501 
502 		repolen = strlen(repo_abspath);
503 		cwdlen = strlen(cwd);
504 		len = strlen(path);
505 
506 		if (len > repolen && strncmp(path, repo_abspath, repolen) == 0)
507 			is_repo_child = 1;
508 		if (len > cwdlen && strncmp(path, cwd, cwdlen) == 0)
509 			is_cwd_child = 1;
510 
511 		if (strcmp(path, repo_abspath) == 0) {
512 			free(path);
513 			path = strdup("");
514 			if (path == NULL) {
515 				err = got_error_from_errno("strdup");
516 				goto done;
517 			}
518 		} else if (is_repo_child && is_cwd_child) {
519 			char *child;
520 			/* Strip common prefix with repository path. */
521 			err = got_path_skip_common_ancestor(&child,
522 			    repo_abspath, path);
523 			if (err)
524 				goto done;
525 			free(path);
526 			path = child;
527 		} else if (is_repo_child) {
528 			/* Matched an on-disk path inside repository. */
529 			if (got_repo_is_bare(repo)) {
530 				/*
531 				 * Matched an on-disk path inside repository
532 				 * database. Treat as repository-relative.
533 				 */
534 			} else {
535 				char *child;
536 				/* Strip common prefix with repository path. */
537 				err = got_path_skip_common_ancestor(&child,
538 				    repo_abspath, path);
539 				if (err)
540 					goto done;
541 				free(path);
542 				path = child;
543 			}
544 		} else if (is_cwd_child) {
545 			char *child;
546 			/* Strip common prefix with cwd. */
547 			err = got_path_skip_common_ancestor(&child, cwd,
548 			    path);
549 			if (err)
550 				goto done;
551 			free(path);
552 			path = child;
553 		} else {
554 			/*
555 			 * Matched unrelated on-disk path.
556 			 * Treat it as repository-relative.
557 			 */
558 		}
559 	}
560 
561 	/* Make in-repository path absolute */
562 	if (path[0] != '/') {
563 		char *abspath;
564 		if (asprintf(&abspath, "/%s", path) == -1) {
565 			err = got_error_from_errno("asprintf");
566 			goto done;
567 		}
568 		free(path);
569 		path = abspath;
570 	}
571 
572 done:
573 	free(cwd);
574 	free(canonpath);
575 	if (err)
576 		free(path);
577 	else
578 		*in_repo_path = path;
579 	return err;
580 }
581 
582 const struct got_error *
583 got_repo_cache_packidx(struct got_repository *repo, struct got_packidx *packidx)
584 {
585 	const struct got_error *err = NULL;
586 	int i;
587 
588 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
589 		if (repo->packidx_cache[i] == NULL)
590 			break;
591 	}
592 	if (i == nitems(repo->packidx_cache)) {
593 		err = got_packidx_close(repo->packidx_cache[i - 1]);
594 		if (err)
595 			return err;
596 	}
597 
598 	/*
599 	 * Insert the new pack index at the front so it will
600 	 * be searched first in the future.
601 	 */
602 	memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
603 	    sizeof(repo->packidx_cache) -
604 	    sizeof(repo->packidx_cache[0]));
605 	repo->packidx_cache[0] = packidx;
606 
607 	return NULL;
608 }
609 
610 static int
611 is_packidx_filename(const char *name, size_t len)
612 {
613 	if (len != GOT_PACKIDX_NAMELEN)
614 		return 0;
615 
616 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
617 		return 0;
618 
619 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
620 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
621 		return 0;
622 
623 	return 1;
624 }
625 
626 const struct got_error *
627 got_repo_search_packidx(struct got_packidx **packidx, int *idx,
628     struct got_repository *repo, struct got_object_id *id)
629 {
630 	const struct got_error *err;
631 	char *path_packdir;
632 	DIR *packdir;
633 	struct dirent *dent;
634 	char *path_packidx;
635 	int i;
636 
637 	/* Search pack index cache. */
638 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
639 		if (repo->packidx_cache[i] == NULL)
640 			break;
641 		*idx = got_packidx_get_object_idx(repo->packidx_cache[i], id);
642 		if (*idx != -1) {
643 			*packidx = repo->packidx_cache[i];
644 			return NULL;
645 		}
646 	}
647 	/* No luck. Search the filesystem. */
648 
649 	path_packdir = got_repo_get_path_objects_pack(repo);
650 	if (path_packdir == NULL)
651 		return got_error_from_errno("got_repo_get_path_objects_pack");
652 
653 	packdir = opendir(path_packdir);
654 	if (packdir == NULL) {
655 		err = got_error_from_errno2("opendir", path_packdir);
656 		goto done;
657 	}
658 
659 	while ((dent = readdir(packdir)) != NULL) {
660 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
661 			continue;
662 
663 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
664 		    dent->d_name) == -1) {
665 			err = got_error_from_errno("asprintf");
666 			goto done;
667 		}
668 
669 		err = got_packidx_open(packidx, path_packidx, 0);
670 		free(path_packidx);
671 		if (err)
672 			goto done;
673 
674 		*idx = got_packidx_get_object_idx(*packidx, id);
675 		if (*idx != -1) {
676 			err = NULL; /* found the object */
677 			err = got_repo_cache_packidx(repo, *packidx);
678 			goto done;
679 		}
680 
681 		err = got_packidx_close(*packidx);
682 		*packidx = NULL;
683 		if (err)
684 			goto done;
685 	}
686 
687 	err = got_error_no_obj(id);
688 done:
689 	free(path_packdir);
690 	if (packdir && closedir(packdir) != 0 && err == NULL)
691 		err = got_error_from_errno("closedir");
692 	return err;
693 }
694 
695 static const struct got_error *
696 read_packfile_hdr(int fd, struct got_packidx *packidx)
697 {
698 	const struct got_error *err = NULL;
699 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
700 	struct got_packfile_hdr hdr;
701 	ssize_t n;
702 
703 	n = read(fd, &hdr, sizeof(hdr));
704 	if (n < 0)
705 		return got_error_from_errno("read");
706 	if (n != sizeof(hdr))
707 		return got_error(GOT_ERR_BAD_PACKFILE);
708 
709 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
710 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
711 	    betoh32(hdr.nobjects) != totobj)
712 		err = got_error(GOT_ERR_BAD_PACKFILE);
713 
714 	return err;
715 }
716 
717 static const struct got_error *
718 open_packfile(int *fd, const char *path_packfile, struct got_packidx *packidx)
719 {
720 	const struct got_error *err = NULL;
721 
722 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW);
723 	if (*fd == -1)
724 		return got_error_from_errno2("open", path_packfile);
725 
726 	if (packidx) {
727 		err = read_packfile_hdr(*fd, packidx);
728 		if (err) {
729 			close(*fd);
730 			*fd = -1;
731 		}
732 	}
733 
734 	return err;
735 }
736 
737 const struct got_error *
738 got_repo_cache_pack(struct got_pack **packp, struct got_repository *repo,
739     const char *path_packfile, struct got_packidx *packidx)
740 {
741 	const struct got_error *err = NULL;
742 	struct got_pack *pack = NULL;
743 	struct stat sb;
744 	int i;
745 
746 	if (packp)
747 		*packp = NULL;
748 
749 	for (i = 0; i < nitems(repo->packs); i++) {
750 		pack = &repo->packs[i];
751 		if (pack->path_packfile == NULL)
752 			break;
753 		if (strcmp(pack->path_packfile, path_packfile) == 0)
754 			return NULL;
755 	}
756 
757 	if (i == nitems(repo->packs) - 1) {
758 		err = got_pack_close(&repo->packs[i - 1]);
759 		if (err)
760 			return err;
761 		memmove(&repo->packs[1], &repo->packs[0],
762 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
763 		i = 0;
764 	}
765 
766 	pack = &repo->packs[i];
767 
768 	pack->path_packfile = strdup(path_packfile);
769 	if (pack->path_packfile == NULL) {
770 		err = got_error_from_errno("strdup");
771 		goto done;
772 	}
773 
774 	err = open_packfile(&pack->fd, path_packfile, packidx);
775 	if (err)
776 		goto done;
777 
778 	if (fstat(pack->fd, &sb) != 0) {
779 		err = got_error_from_errno("fstat");
780 		goto done;
781 	}
782 	pack->filesize = sb.st_size;
783 
784 	pack->privsep_child = NULL;
785 
786 #ifndef GOT_PACK_NO_MMAP
787 	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
788 	    pack->fd, 0);
789 	if (pack->map == MAP_FAILED) {
790 		if (errno != ENOMEM) {
791 			err = got_error_from_errno("mmap");
792 			goto done;
793 		}
794 		pack->map = NULL; /* fall back to read(2) */
795 	}
796 #endif
797 done:
798 	if (err) {
799 		if (pack) {
800 			free(pack->path_packfile);
801 			memset(pack, 0, sizeof(*pack));
802 		}
803 	} else if (packp)
804 		*packp = pack;
805 	return err;
806 }
807 
808 struct got_pack *
809 got_repo_get_cached_pack(struct got_repository *repo, const char *path_packfile)
810 {
811 	struct got_pack *pack = NULL;
812 	int i;
813 
814 	for (i = 0; i < nitems(repo->packs); i++) {
815 		pack = &repo->packs[i];
816 		if (pack->path_packfile == NULL)
817 			break;
818 		if (strcmp(pack->path_packfile, path_packfile) == 0)
819 			return pack;
820 	}
821 
822 	return NULL;
823 }
824 
825 const struct got_error *
826 got_repo_init(const char *repo_path)
827 {
828 	const struct got_error *err = NULL;
829 	const char *dirnames[] = {
830 		GOT_OBJECTS_DIR,
831 		GOT_OBJECTS_PACK_DIR,
832 		GOT_REFS_DIR,
833 	};
834 	const char *description_str = "Unnamed repository; "
835 	    "edit this file 'description' to name the repository.";
836 	const char *headref_str = "ref: refs/heads/master";
837 	const char *gitconfig_str = "[core]\n"
838 	    "\trepositoryformatversion = 0\n"
839 	    "\tfilemode = true\n"
840 	    "\tbare = true\n";
841 	char *path;
842 	int i;
843 
844 	if (!got_path_dir_is_empty(repo_path))
845 		return got_error(GOT_ERR_DIR_NOT_EMPTY);
846 
847 	for (i = 0; i < nitems(dirnames); i++) {
848 		if (asprintf(&path, "%s/%s", repo_path, dirnames[i]) == -1) {
849 			return got_error_from_errno("asprintf");
850 		}
851 		err = got_path_mkdir(path);
852 		free(path);
853 		if (err)
854 			return err;
855 	}
856 
857 	if (asprintf(&path, "%s/%s", repo_path, "description") == -1)
858 		return got_error_from_errno("asprintf");
859 	err = got_path_create_file(path, description_str);
860 	free(path);
861 	if (err)
862 		return err;
863 
864 	if (asprintf(&path, "%s/%s", repo_path, GOT_HEAD_FILE) == -1)
865 		return got_error_from_errno("asprintf");
866 	err = got_path_create_file(path, headref_str);
867 	free(path);
868 	if (err)
869 		return err;
870 
871 	if (asprintf(&path, "%s/%s", repo_path, "config") == -1)
872 		return got_error_from_errno("asprintf");
873 	err = got_path_create_file(path, gitconfig_str);
874 	free(path);
875 	if (err)
876 		return err;
877 
878 	return NULL;
879 }
880 
881 static const struct got_error *
882 match_packed_object(struct got_object_id **unique_id,
883     struct got_repository *repo, const char *id_str_prefix, int obj_type)
884 {
885 	const struct got_error *err = NULL;
886 	char *path_packdir;
887 	DIR *packdir;
888 	struct dirent *dent;
889 	char *path_packidx;
890 	struct got_object_id_queue matched_ids;
891 
892 	SIMPLEQ_INIT(&matched_ids);
893 
894 	path_packdir = got_repo_get_path_objects_pack(repo);
895 	if (path_packdir == NULL)
896 		return got_error_from_errno("got_repo_get_path_objects_pack");
897 
898 	packdir = opendir(path_packdir);
899 	if (packdir == NULL) {
900 		err = got_error_from_errno2("opendir", path_packdir);
901 		goto done;
902 	}
903 
904 	while ((dent = readdir(packdir)) != NULL) {
905 		struct got_packidx *packidx;
906 		struct got_object_qid *qid;
907 
908 
909 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
910 			continue;
911 
912 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
913 		    dent->d_name) == -1) {
914 			err = got_error_from_errno("asprintf");
915 			break;
916 		}
917 
918 		err = got_packidx_open(&packidx, path_packidx, 0);
919 		free(path_packidx);
920 		if (err)
921 			break;
922 
923 		err = got_packidx_match_id_str_prefix(&matched_ids,
924 		    packidx, id_str_prefix);
925 		if (err) {
926 			got_packidx_close(packidx);
927 			break;
928 		}
929 		err = got_packidx_close(packidx);
930 		if (err)
931 			break;
932 
933 		SIMPLEQ_FOREACH(qid, &matched_ids, entry) {
934 			if (obj_type != GOT_OBJ_TYPE_ANY) {
935 				int matched_type;
936 				err = got_object_get_type(&matched_type, repo,
937 				    qid->id);
938 				if (err)
939 					goto done;
940 				if (matched_type != obj_type)
941 					continue;
942 			}
943 			if (*unique_id == NULL) {
944 				*unique_id = got_object_id_dup(qid->id);
945 				if (*unique_id == NULL) {
946 					err = got_error_from_errno("malloc");
947 					goto done;
948 				}
949 			} else {
950 				err = got_error(GOT_ERR_AMBIGUOUS_ID);
951 				goto done;
952 			}
953 		}
954 	}
955 done:
956 	got_object_id_queue_free(&matched_ids);
957 	free(path_packdir);
958 	if (packdir && closedir(packdir) != 0 && err == NULL)
959 		err = got_error_from_errno("closedir");
960 	if (err) {
961 		free(*unique_id);
962 		*unique_id = NULL;
963 	}
964 	return err;
965 }
966 
967 static const struct got_error *
968 match_loose_object(struct got_object_id **unique_id, const char *path_objects,
969     const char *object_dir, const char *id_str_prefix, int obj_type,
970     struct got_repository *repo)
971 {
972 	const struct got_error *err = NULL;
973 	char *path;
974 	DIR *dir = NULL;
975 	struct dirent *dent;
976 	struct got_object_id id;
977 
978 	if (asprintf(&path, "%s/%s", path_objects, object_dir) == -1) {
979 		err = got_error_from_errno("asprintf");
980 		goto done;
981 	}
982 
983 	dir = opendir(path);
984 	if (dir == NULL) {
985 		if (errno == ENOENT) {
986 			err = NULL;
987 			goto done;
988 		}
989 		err = got_error_from_errno2("opendir", path);
990 		goto done;
991 	}
992 	while ((dent = readdir(dir)) != NULL) {
993 		char *id_str;
994 		int cmp;
995 
996 		if (strcmp(dent->d_name, ".") == 0 ||
997 		    strcmp(dent->d_name, "..") == 0)
998 			continue;
999 
1000 		if (asprintf(&id_str, "%s%s", object_dir, dent->d_name) == -1) {
1001 			err = got_error_from_errno("asprintf");
1002 			goto done;
1003 		}
1004 
1005 		if (!got_parse_sha1_digest(id.sha1, id_str))
1006 			continue;
1007 
1008 		/*
1009 		 * Directory entries do not necessarily appear in
1010 		 * sorted order, so we must iterate over all of them.
1011 		 */
1012 		cmp = strncmp(id_str, id_str_prefix, strlen(id_str_prefix));
1013 		if (cmp != 0) {
1014 			free(id_str);
1015 			continue;
1016 		}
1017 
1018 		if (*unique_id == NULL) {
1019 			if (obj_type != GOT_OBJ_TYPE_ANY) {
1020 				int matched_type;
1021 				err = got_object_get_type(&matched_type, repo,
1022 				    &id);
1023 				if (err)
1024 					goto done;
1025 				if (matched_type != obj_type)
1026 					continue;
1027 			}
1028 			*unique_id = got_object_id_dup(&id);
1029 			if (*unique_id == NULL) {
1030 				err = got_error_from_errno("got_object_id_dup");
1031 				free(id_str);
1032 				goto done;
1033 			}
1034 		} else {
1035 			err = got_error(GOT_ERR_AMBIGUOUS_ID);
1036 			free(id_str);
1037 			goto done;
1038 		}
1039 	}
1040 done:
1041 	if (dir && closedir(dir) != 0 && err == NULL)
1042 		err = got_error_from_errno("closedir");
1043 	if (err) {
1044 		free(*unique_id);
1045 		*unique_id = NULL;
1046 	}
1047 	free(path);
1048 	return err;
1049 }
1050 
1051 const struct got_error *
1052 got_repo_match_object_id_prefix(struct got_object_id **id,
1053     const char *id_str_prefix, int obj_type, struct got_repository *repo)
1054 {
1055 	const struct got_error *err = NULL;
1056 	char *path_objects = got_repo_get_path_objects(repo);
1057 	char *object_dir = NULL;
1058 	size_t len;
1059 	int i;
1060 
1061 	*id = NULL;
1062 
1063 	for (i = 0; i < strlen(id_str_prefix); i++) {
1064 		if (isxdigit((unsigned char)id_str_prefix[i]))
1065 			continue;
1066 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
1067 	}
1068 
1069 	len = strlen(id_str_prefix);
1070 	if (len >= 2) {
1071 		err = match_packed_object(id, repo, id_str_prefix, obj_type);
1072 		if (err)
1073 			goto done;
1074 		object_dir = strndup(id_str_prefix, 2);
1075 		if (object_dir == NULL) {
1076 			err = got_error_from_errno("strdup");
1077 			goto done;
1078 		}
1079 		err = match_loose_object(id, path_objects, object_dir,
1080 		    id_str_prefix, obj_type, repo);
1081 	} else if (len == 1) {
1082 		int i;
1083 		for (i = 0; i < 0xf; i++) {
1084 			if (asprintf(&object_dir, "%s%.1x", id_str_prefix, i)
1085 			    == -1) {
1086 				err = got_error_from_errno("asprintf");
1087 				goto done;
1088 			}
1089 			err = match_packed_object(id, repo, object_dir,
1090 			    obj_type);
1091 			if (err)
1092 				goto done;
1093 			err = match_loose_object(id, path_objects, object_dir,
1094 			    id_str_prefix, obj_type, repo);
1095 			if (err)
1096 				goto done;
1097 		}
1098 	} else {
1099 		err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
1100 		goto done;
1101 	}
1102 done:
1103 	free(object_dir);
1104 	if (err) {
1105 		free(*id);
1106 		*id = NULL;
1107 	} else if (*id == NULL)
1108 		err = got_error(GOT_ERR_NO_OBJ);
1109 
1110 	return err;
1111 }