Got Mirror

Blob

Date:: Mon Sep 10 10:30:47 2018 UTC
Message:: start reading pack files with privsep; still WIP
Actions:: History | Blame | Raw File
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/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 <fcntl.h>
25 #include <limits.h>
26 #include <dirent.h>
27 #include <stdlib.h>
28 #include <stdio.h>
29 #include <sha1.h>
30 #include <string.h>
31 #include <zlib.h>
32 #include <errno.h>
33 #include <libgen.h>
34 #include <stdint.h>
35 #include <imsg.h>
36 
37 #include "got_error.h"
38 #include "got_reference.h"
39 #include "got_repository.h"
40 #include "got_worktree.h"
41 #include "got_object.h"
42 
43 #include "got_lib_path.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_inflate.h"
46 #include "got_lib_object.h"
47 #include "got_lib_pack.h"
48 #include "got_lib_privsep.h"
49 #include "got_lib_repository.h"
50 #include "got_lib_worktree.h"
51 #include "got_lib_object_idcache.h"
52 
53 #ifndef nitems
54 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
55 #endif
56 
57 #define GOT_GIT_DIR	".git"
58 
59 /* Mandatory files and directories inside the git directory. */
60 #define GOT_OBJECTS_DIR		"objects"
61 #define GOT_REFS_DIR		"refs"
62 #define GOT_HEAD_FILE		"HEAD"
63 
64 /* Other files and directories inside the git directory. */
65 #define GOT_FETCH_HEAD_FILE	"FETCH_HEAD"
66 #define GOT_ORIG_HEAD_FILE	"ORIG_HEAD"
67 #define GOT_OBJECTS_PACK_DIR	"objects/pack"
68 
69 char *
70 got_repo_get_path(struct got_repository *repo)
71 {
72 	return strdup(repo->path);
73 }
74 
75 char *
76 got_repo_get_path_git_dir(struct got_repository *repo)
77 {
78 	return strdup(repo->path_git_dir);
79 }
80 
81 int
82 got_repo_is_bare(struct got_repository *repo)
83 {
84 	return (strcmp(repo->path, repo->path_git_dir) == 0);
85 }
86 
87 static char *
88 get_path_git_child(struct got_repository *repo, const char *basename)
89 {
90 	char *path_child;
91 	
92 	if (asprintf(&path_child, "%s/%s", repo->path_git_dir,
93 	    basename) == -1)
94 		return NULL;
95 
96 	return path_child;
97 }
98 
99 char *
100 got_repo_get_path_objects(struct got_repository *repo)
101 {
102 	return get_path_git_child(repo, GOT_OBJECTS_DIR);
103 }
104 
105 char *
106 got_repo_get_path_objects_pack(struct got_repository *repo)
107 {
108 	return get_path_git_child(repo, GOT_OBJECTS_PACK_DIR);
109 }
110 
111 char *
112 got_repo_get_path_refs(struct got_repository *repo)
113 {
114 	return get_path_git_child(repo, GOT_REFS_DIR);
115 }
116 
117 static char *
118 get_path_head(struct got_repository *repo)
119 {
120 	return get_path_git_child(repo, GOT_HEAD_FILE);
121 }
122 
123 static int
124 is_git_repo(struct got_repository *repo)
125 {
126 	char *path_git = got_repo_get_path_git_dir(repo);
127 	char *path_objects = got_repo_get_path_objects(repo);
128 	char *path_refs = got_repo_get_path_refs(repo);
129 	char *path_head = get_path_head(repo);
130 	int ret = 0;
131 	struct stat sb;
132 	struct got_reference *head_ref;
133 
134 	if (lstat(path_git, &sb) == -1)
135 		goto done;
136 	if (!S_ISDIR(sb.st_mode))
137 		goto done;
138 
139 	if (lstat(path_objects, &sb) == -1)
140 		goto done;
141 	if (!S_ISDIR(sb.st_mode))
142 		goto done;
143 
144 	if (lstat(path_refs, &sb) == -1)
145 		goto done;
146 	if (!S_ISDIR(sb.st_mode))
147 		goto done;
148 
149 	if (lstat(path_head, &sb) == -1)
150 		goto done;
151 	if (!S_ISREG(sb.st_mode))
152 		goto done;
153 
154 	/* Check if the HEAD reference can be opened. */
155 	if (got_ref_open(&head_ref, repo, GOT_REF_HEAD) != NULL)
156 		goto done;
157 	got_ref_close(head_ref);
158 
159 	ret = 1;
160 done:
161 	free(path_git);
162 	free(path_objects);
163 	free(path_refs);
164 	free(path_head);
165 	return ret;
166 
167 }
168 
169 #ifndef GOT_NO_OBJ_CACHE
170 static const struct got_error *
171 cache_add(struct got_object_cache *cache, struct got_object_id *id, void *item)
172 {
173 	const struct got_error *err = NULL;
174 	struct got_object_cache_entry *ce;
175 	int nelem;
176 
177 	nelem = got_object_idcache_num_elements(cache->idcache);
178 	if (nelem >= cache->size) {
179 		err = got_object_idcache_remove_least_used((void **)&ce,
180 		    cache->idcache);
181 		if (err)
182 			return err;
183 		switch (cache->type) {
184 		case GOT_OBJECT_CACHE_TYPE_OBJ:
185 			got_object_close(ce->data.obj);
186 			break;
187 		case GOT_OBJECT_CACHE_TYPE_TREE:
188 			got_object_tree_close(ce->data.tree);
189 			break;
190 		case GOT_OBJECT_CACHE_TYPE_COMMIT:
191 			got_object_commit_close(ce->data.commit);
192 			break;
193 		}
194 		free(ce);
195 	}
196 
197 	ce = calloc(1, sizeof(*ce));
198 	if (ce == NULL)
199 		return got_error_from_errno();
200 	memcpy(&ce->id, id, sizeof(ce->id));
201 	switch (cache->type) {
202 	case GOT_OBJECT_CACHE_TYPE_OBJ:
203 		ce->data.obj = (struct got_object *)item;
204 		break;
205 	case GOT_OBJECT_CACHE_TYPE_TREE:
206 		ce->data.tree = (struct got_tree_object *)item;
207 		break;
208 	case GOT_OBJECT_CACHE_TYPE_COMMIT:
209 		ce->data.commit = (struct got_commit_object *)item;
210 		break;
211 	}
212 
213 	err = got_object_idcache_add(cache->idcache, id, ce);
214 	if (err) {
215 		if (err->code == GOT_ERR_OBJ_EXISTS) {
216 			free(ce);
217 			err = NULL;
218 		}
219 	}
220 	return err;
221 }
222 #endif
223 
224 const struct got_error *
225 got_repo_cache_object(struct got_repository *repo, struct got_object_id *id,
226     struct got_object *obj)
227 {
228 #ifndef GOT_NO_OBJ_CACHE
229 	const struct got_error *err = NULL;
230 	err = cache_add(&repo->objcache, id, obj);
231 	if (err)
232 		return err;
233 	obj->refcnt++;
234 #endif
235 	return NULL;
236 }
237 
238 struct got_object *
239 got_repo_get_cached_object(struct got_repository *repo,
240     struct got_object_id *id)
241 {
242 	struct got_object_cache_entry *ce;
243 
244 	ce = got_object_idcache_get(repo->objcache.idcache, id);
245 	if (ce) {
246 		repo->objcache.cache_hit++;
247 		return ce->data.obj;
248 	}
249 
250 	repo->objcache.cache_miss++;
251 	return NULL;
252 }
253 
254 const struct got_error *
255 got_repo_cache_tree(struct got_repository *repo, struct got_object_id *id,
256     struct got_tree_object *tree)
257 {
258 #ifndef GOT_NO_OBJ_CACHE
259 	const struct got_error *err = NULL;
260 	err = cache_add(&repo->treecache, id, tree);
261 	if (err)
262 		return err;
263 	tree->refcnt++;
264 #endif
265 	return NULL;
266 }
267 
268 struct got_tree_object *
269 got_repo_get_cached_tree(struct got_repository *repo,
270     struct got_object_id *id)
271 {
272 	struct got_object_cache_entry *ce;
273 
274 	ce = got_object_idcache_get(repo->treecache.idcache, id);
275 	if (ce) {
276 		repo->treecache.cache_hit++;
277 		return ce->data.tree;
278 	}
279 
280 	repo->treecache.cache_miss++;
281 	return NULL;
282 }
283 
284 const struct got_error *
285 got_repo_cache_commit(struct got_repository *repo, struct got_object_id *id,
286     struct got_commit_object *commit)
287 {
288 #ifndef GOT_NO_OBJ_CACHE
289 	const struct got_error *err = NULL;
290 	err = cache_add(&repo->commitcache, id, commit);
291 	if (err)
292 		return err;
293 
294 	commit->refcnt++;
295 #endif
296 	return NULL;
297 }
298 
299 struct got_commit_object *
300 got_repo_get_cached_commit(struct got_repository *repo,
301     struct got_object_id *id)
302 {
303 	struct got_object_cache_entry *ce;
304 
305 	ce = got_object_idcache_get(repo->commitcache.idcache, id);
306 	if (ce) {
307 		repo->commitcache.cache_hit++;
308 		return ce->data.commit;
309 	}
310 
311 	repo->commitcache.cache_miss++;
312 	return NULL;
313 }
314 
315 const struct got_error *
316 open_repo(struct got_repository *repo, const char *path)
317 {
318 	const struct got_error *err = NULL;
319 	struct got_worktree *worktree = NULL;
320 
321 	/* bare git repository? */
322 	repo->path_git_dir = strdup(path);
323 	if (repo->path_git_dir == NULL) {
324 		err = got_error_from_errno();
325 		goto done;
326 	}
327 	if (is_git_repo(repo)) {
328 		repo->path = strdup(repo->path_git_dir);
329 		if (repo->path == NULL) {
330 			err = got_error_from_errno();
331 			goto done;
332 		}
333 		return NULL;
334 	}
335 
336 	/* git repository with working tree? */
337 	free(repo->path_git_dir);
338 	if (asprintf(&repo->path_git_dir, "%s/%s", path, GOT_GIT_DIR) == -1) {
339 		err = got_error_from_errno();
340 		goto done;
341 	}
342 	if (is_git_repo(repo)) {
343 		repo->path = strdup(path);
344 		if (repo->path == NULL) {
345 			err = got_error_from_errno();
346 			goto done;
347 		}
348 		return NULL;
349 	}
350 
351 	/* got work tree checked out from bare git repository? */
352 	free(repo->path_git_dir);
353 	repo->path_git_dir = NULL;
354 	err = got_worktree_open(&worktree, path);
355 	if (err) {
356 		if (err->code == GOT_ERR_ERRNO && errno == ENOENT)
357 			err = got_error(GOT_ERR_NOT_GIT_REPO);
358 		goto done;
359 	}
360 	repo->path_git_dir = strdup(worktree->repo_path);
361 	if (repo->path_git_dir == NULL) {
362 		err = got_error_from_errno();
363 		goto done;
364 	}
365 
366 	/* got work tree checked out from git repository with working tree? */
367 	if (!is_git_repo(repo)) {
368 		free(repo->path_git_dir);
369 		if (asprintf(&repo->path_git_dir, "%s/%s", worktree->repo_path,
370 		    GOT_GIT_DIR) == -1) {
371 			err = got_error_from_errno();
372 			repo->path_git_dir = NULL;
373 			goto done;
374 		}
375 		if (!is_git_repo(repo)) {
376 			err = got_error(GOT_ERR_NOT_GIT_REPO);
377 			goto done;
378 		}
379 		repo->path = strdup(worktree->repo_path);
380 		if (repo->path == NULL) {
381 			err = got_error_from_errno();
382 			goto done;
383 		}
384 	} else {
385 		repo->path = strdup(repo->path_git_dir);
386 		if (repo->path == NULL) {
387 			err = got_error_from_errno();
388 			goto done;
389 		}
390 	}
391 done:
392 	if (worktree)
393 		got_worktree_close(worktree);
394 	return err;
395 }
396 
397 const struct got_error *
398 got_repo_open(struct got_repository **repop, const char *path)
399 {
400 	struct got_repository *repo = NULL;
401 	const struct got_error *err = NULL;
402 	char *abspath, *normpath = NULL;
403 	int i, tried_root = 0;
404 
405 	*repop = NULL;
406 
407 	if (got_path_is_absolute(path))
408 		abspath = strdup(path);
409 	else
410 		abspath = got_path_get_absolute(path);
411 	if (abspath == NULL)
412 		return got_error(GOT_ERR_BAD_PATH);
413 
414 	repo = calloc(1, sizeof(*repo));
415 	if (repo == NULL) {
416 		err = got_error_from_errno();
417 		goto done;
418 	}
419 
420 	for (i = 0; i < nitems(repo->privsep_children); i++) {
421 		memset(&repo->privsep_children[i], 0,
422 		    sizeof(repo->privsep_children[0]));
423 		repo->privsep_children[i].imsg_fd = -1;
424 	}
425 
426 	repo->objcache.type = GOT_OBJECT_CACHE_TYPE_OBJ;
427 	repo->objcache.size = GOT_OBJECT_CACHE_SIZE_OBJ;
428 	repo->objcache.idcache = got_object_idcache_alloc(repo->objcache.size);
429 	if (repo->objcache.idcache == NULL) {
430 		err = got_error_from_errno();
431 		goto done;
432 	}
433 
434 	repo->treecache.type = GOT_OBJECT_CACHE_TYPE_TREE;
435 	repo->treecache.size = GOT_OBJECT_CACHE_SIZE_TREE;
436 	repo->treecache.idcache =
437 	    got_object_idcache_alloc(repo->treecache.size);
438 	if (repo->treecache.idcache == NULL) {
439 		err = got_error_from_errno();
440 		goto done;
441 	}
442 
443 	repo->commitcache.type = GOT_OBJECT_CACHE_TYPE_COMMIT;
444 	repo->commitcache.size = GOT_OBJECT_CACHE_SIZE_COMMIT;
445 	repo->commitcache.idcache =
446 	    got_object_idcache_alloc(repo->commitcache.size);
447 	if (repo->commitcache.idcache == NULL) {
448 		err = got_error_from_errno();
449 		goto done;
450 	}
451 
452 	normpath = got_path_normalize(abspath);
453 	if (normpath == NULL) {
454 		err = got_error(GOT_ERR_BAD_PATH);
455 		goto done;
456 	}
457 
458 	path = normpath;
459 	do {
460 		err = open_repo(repo, path);
461 		if (err == NULL)
462 			break;
463 		if (err->code != GOT_ERR_NOT_GIT_REPO)
464 			break;
465 		if (path[0] == '/' && path[1] == '\0') {
466 			if (tried_root) {
467 				err = got_error(GOT_ERR_NOT_GIT_REPO);
468 				break;
469 			}
470 			tried_root = 1;
471 		}
472 		path = dirname(path);
473 		if (path == NULL)
474 			err = got_error_from_errno();
475 	} while (path);
476 done:
477 	if (err)
478 		err = got_repo_close(repo);
479 	else
480 		*repop = repo;
481 	free(abspath);
482 	free(normpath);
483 	return err;
484 }
485 
486 #if 0
487 static void
488 print_cache_stats(struct got_object_cache *cache, const char *name)
489 {
490 	fprintf(stderr, "%s cache: %d elements, %d hits, %d missed\n",
491 	    name, got_object_idcache_num_elements(cache->idcache),
492 	    cache->cache_hit, cache->cache_miss);
493 }
494 
495 void check_refcount(struct got_object_id *id, void *data, void *arg)
496 {
497 	struct got_object_cache *cache = arg;
498 	struct got_object_cache_entry *ce = data;
499 	struct got_object *obj;
500 	struct got_tree_object *tree;
501 	struct got_commit_object *commit;
502 	char *id_str;
503 
504 	if (got_object_id_str(&id_str, id) != NULL)
505 		return;
506 
507 	switch (cache->type) {
508 	case GOT_OBJECT_CACHE_TYPE_OBJ:
509 		obj = ce->data.obj;
510 		if (obj->refcnt == 1)
511 			break;
512 		fprintf(stderr, "object %s has %d unclaimed references\n",
513 		    id_str, obj->refcnt - 1);
514 		break;
515 	case GOT_OBJECT_CACHE_TYPE_TREE:
516 		tree = ce->data.tree;
517 		if (tree->refcnt == 1)
518 			break;
519 		fprintf(stderr, "tree %s has %d unclaimed references\n",
520 		    id_str, tree->refcnt - 1);
521 		break;
522 	case GOT_OBJECT_CACHE_TYPE_COMMIT:
523 		commit = ce->data.commit;
524 		if (commit->refcnt == 1)
525 			break;
526 		fprintf(stderr, "commit %s has %d unclaimed references\n",
527 		    id_str, commit->refcnt);
528 		break;
529 	}
530 	free(id_str);
531 }
532 #endif
533 
534 const struct got_error *
535 got_repo_close(struct got_repository *repo)
536 {
537 	const struct got_error *err = NULL, *child_err;
538 	int i;
539 
540 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
541 		if (repo->packidx_cache[i] == NULL)
542 			break;
543 		got_packidx_close(repo->packidx_cache[i]);
544 	}
545 
546 	for (i = 0; i < nitems(repo->packs); i++) {
547 		if (repo->packs[i].path_packfile == NULL)
548 			break;
549 		got_pack_close(&repo->packs[i]);
550 	}
551 
552 	free(repo->path);
553 	free(repo->path_git_dir);
554 
555 #if 0
556 	print_cache_stats(&repo->objcache, "object");
557 	print_cache_stats(&repo->treecache, "tree");
558 	print_cache_stats(&repo->commitcache, "commit");
559 	got_object_idcache_for_each(repo->objcache.idcache, check_refcount,
560 	    &repo->objcache);
561 	got_object_idcache_for_each(repo->treecache.idcache, check_refcount,
562 	    &repo->treecache);
563 	got_object_idcache_for_each(repo->commitcache.idcache, check_refcount,
564 	    &repo->commitcache);
565 #endif
566 
567 	if (repo->objcache.idcache)
568 		got_object_idcache_free(repo->objcache.idcache);
569 	if (repo->treecache.idcache)
570 		got_object_idcache_free(repo->treecache.idcache);
571 	if (repo->commitcache.idcache)
572 		got_object_idcache_free(repo->commitcache.idcache);
573 
574 	for (i = 0; i < nitems(repo->privsep_children); i++) {
575 		if (repo->privsep_children[i].imsg_fd == -1)
576 			continue;
577 		imsg_clear(repo->privsep_children[i].ibuf);
578 		free(repo->privsep_children[i].ibuf);
579 		err = got_privsep_send_stop(repo->privsep_children[i].imsg_fd);
580 		child_err = got_privsep_wait_for_child(
581 		    repo->privsep_children[i].pid);
582 		if (child_err && err == NULL)
583 			err = child_err;
584 		close(repo->privsep_children[i].imsg_fd);
585 	}
586 	free(repo);
587 
588 	return err;
589 }
590 
591 const struct got_error *
592 got_repo_map_path(char **in_repo_path, struct got_repository *repo,
593     const char *input_path)
594 {
595 	const struct got_error *err = NULL;
596 	char *repo_abspath = NULL, *cwd = NULL;
597 	struct stat sb;
598 	size_t repolen, cwdlen, len;
599 	char *canonpath, *path;
600 
601 	*in_repo_path = NULL;
602 
603 	cwd = getcwd(NULL, 0);
604 	if (cwd == NULL)
605 		return got_error_from_errno();
606 
607 	canonpath = strdup(input_path);
608 	if (canonpath == NULL) {
609 		err = got_error_from_errno();
610 		goto done;
611 	}
612 	err = got_canonpath(input_path, canonpath, strlen(canonpath) + 1);
613 	if (err)
614 		goto done;
615 
616 	repo_abspath = got_repo_get_path(repo);
617 	if (repo_abspath == NULL) {
618 		err = got_error_from_errno();
619 		goto done;
620 	}
621 
622 	/* TODO: Call "get in-repository path of work-tree node" API. */
623 
624 	if (lstat(canonpath, &sb) != 0) {
625 		if (errno != ENOENT) {
626 			err = got_error_from_errno();
627 			goto done;
628 		}
629 		/*
630 		 * Path is not on disk.
631 		 * Assume it is already relative to repository root.
632 		 */
633 		path = strdup(canonpath);
634 	} else {
635 		int is_repo_child = 0, is_cwd_child = 0;
636 
637 		path = realpath(canonpath, NULL);
638 		if (path == NULL) {
639 			err = got_error_from_errno();
640 			goto done;
641 		}
642 
643 		repolen = strlen(repo_abspath);
644 		cwdlen = strlen(cwd);
645 		len = strlen(path);
646 
647 		if (len > repolen && strncmp(path, repo_abspath, repolen) == 0)
648 			is_repo_child = 1;
649 		if (len > cwdlen && strncmp(path, cwd, cwdlen) == 0)
650 			is_cwd_child = 1;
651 
652 		if (strcmp(path, repo_abspath) == 0) {
653 			free(path);
654 			path = strdup("");
655 			if (path == NULL) {
656 				err = got_error_from_errno();
657 				goto done;
658 			}
659 		} else if (is_repo_child && is_cwd_child) {
660 			char *child;
661 			/* TODO: Is path inside a got worktree? */
662 			/* Strip common prefix with repository path. */
663 			err = got_path_skip_common_ancestor(&child,
664 			    repo_abspath, path);
665 			if (err)
666 				goto done;
667 			free(path);
668 			path = child;
669 		} else if (is_repo_child) {
670 			/* Matched an on-disk path inside repository. */
671 			if (got_repo_is_bare(repo)) {
672 				/*
673 				 * Matched an on-disk path inside repository
674 				 * database. Treat as repository-relative.
675 				 */
676 			} else {
677 				char *child;
678 				/* Strip common prefix with repository path. */
679 				err = got_path_skip_common_ancestor(&child,
680 				    repo_abspath, path);
681 				if (err)
682 					goto done;
683 				free(path);
684 				path = child;
685 			}
686 		} else if (is_cwd_child) {
687 			char *child;
688 			/* TODO: Is path inside a got worktree? */
689 			/* Strip common prefix with cwd. */
690 			err = got_path_skip_common_ancestor(&child, cwd,
691 			    path);
692 			if (err)
693 				goto done;
694 			free(path);
695 			path = child;
696 		} else {
697 			/*
698 			 * Matched unrelated on-disk path.
699 			 * Treat it as repository-relative.
700 			 */
701 		}
702 	}
703 
704 	/* Make in-repository path absolute */
705 	if (path[0] != '/') {
706 		char *abspath;
707 		if (asprintf(&abspath, "/%s", path) == -1) {
708 			err = got_error_from_errno();
709 			goto done;
710 		}
711 		free(path);
712 		path = abspath;
713 	}
714 
715 done:
716 	free(repo_abspath);
717 	free(cwd);
718 	free(canonpath);
719 	if (err)
720 		free(path);
721 	else
722 		*in_repo_path = path;
723 	return err;
724 }
725 
726 const struct got_error *
727 got_repo_cache_packidx(struct got_repository *repo, struct got_packidx *packidx)
728 {
729 	const struct got_error *err = NULL;
730 	int i;
731 
732 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
733 		if (repo->packidx_cache[i] == NULL)
734 			break;
735 	}
736 
737 	if (i == nitems(repo->packidx_cache)) {
738 		err = got_packidx_close(repo->packidx_cache[i - 1]);
739 		if (err)
740 			return err;
741 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
742 		    sizeof(repo->packidx_cache) -
743 		    sizeof(repo->packidx_cache[0]));
744 		i = 0;
745 	}
746 
747 	repo->packidx_cache[i] = packidx;
748 	return NULL;
749 }
750 
751 static int
752 is_packidx_filename(const char *name, size_t len)
753 {
754 	if (len != GOT_PACKIDX_NAMELEN)
755 		return 0;
756 
757 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
758 		return 0;
759 
760 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
761 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
762 		return 0;
763 
764 	return 1;
765 }
766 
767 const struct got_error *
768 got_repo_search_packidx(struct got_packidx **packidx, int *idx,
769     struct got_repository *repo, struct got_object_id *id)
770 {
771 	const struct got_error *err;
772 	char *path_packdir;
773 	DIR *packdir;
774 	struct dirent *dent;
775 	char *path_packidx;
776 	int i;
777 
778 	/* Search pack index cache. */
779 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
780 		if (repo->packidx_cache[i] == NULL)
781 			break;
782 		*idx = got_packidx_get_object_idx(repo->packidx_cache[i], id);
783 		if (*idx != -1) {
784 			*packidx = repo->packidx_cache[i];
785 			return NULL;
786 		}
787 	}
788 	/* No luck. Search the filesystem. */
789 
790 	path_packdir = got_repo_get_path_objects_pack(repo);
791 	if (path_packdir == NULL)
792 		return got_error_from_errno();
793 
794 	packdir = opendir(path_packdir);
795 	if (packdir == NULL) {
796 		err = got_error_from_errno();
797 		goto done;
798 	}
799 
800 	while ((dent = readdir(packdir)) != NULL) {
801 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
802 			continue;
803 
804 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
805 		    dent->d_name) == -1) {
806 			err = got_error_from_errno();
807 			goto done;
808 		}
809 
810 		err = got_packidx_open(packidx, path_packidx, 0);
811 		free(path_packidx);
812 		if (err)
813 			goto done;
814 
815 		*idx = got_packidx_get_object_idx(*packidx, id);
816 		if (*idx != -1) {
817 			err = NULL; /* found the object */
818 			err = got_repo_cache_packidx(repo, *packidx);
819 			goto done;
820 		}
821 
822 		err = got_packidx_close(*packidx);
823 		*packidx = NULL;
824 		if (err)
825 			goto done;
826 	}
827 
828 	err = got_error(GOT_ERR_NO_OBJ);
829 done:
830 	free(path_packdir);
831 	if (packdir && closedir(packdir) != 0 && err == 0)
832 		err = got_error_from_errno();
833 	return err;
834 }
835 
836 static const struct got_error *
837 read_packfile_hdr(int fd, struct got_packidx *packidx)
838 {
839 	const struct got_error *err = NULL;
840 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
841 	struct got_packfile_hdr hdr;
842 	ssize_t n;
843 
844 	n = read(fd, &hdr, sizeof(hdr));
845 	if (n < 0)
846 		return got_error_from_errno();
847 	if (n != sizeof(hdr))
848 		return got_error(GOT_ERR_BAD_PACKFILE);
849 
850 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
851 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
852 	    betoh32(hdr.nobjects) != totobj)
853 		err = got_error(GOT_ERR_BAD_PACKFILE);
854 
855 	return err;
856 }
857 
858 static const struct got_error *
859 open_packfile(int *fd, const char *path_packfile, struct got_packidx *packidx)
860 {
861 	const struct got_error *err = NULL;
862 
863 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
864 	if (*fd == -1)
865 		return got_error_from_errno();
866 
867 	if (packidx) {
868 		err = read_packfile_hdr(*fd, packidx);
869 		if (err) {
870 			close(*fd);
871 			*fd = -1;
872 		}
873 	}
874 
875 	return err;
876 }
877 
878 const struct got_error *
879 got_repo_cache_pack(struct got_pack **packp, struct got_repository *repo,
880     const char *path_packfile, struct got_packidx *packidx)
881 {
882 	const struct got_error *err = NULL;
883 	struct got_pack *pack = NULL;
884 	int i;
885 
886 	if (packp)
887 		*packp = NULL;
888 
889 	for (i = 0; i < nitems(repo->packs); i++) {
890 		pack = &repo->packs[i];
891 		if (pack->path_packfile == NULL)
892 			break;
893 		if (strcmp(pack->path_packfile, path_packfile) == 0)
894 			return NULL;
895 	}
896 
897 	if (i == nitems(repo->packs) - 1) {
898 		err = got_pack_close(&repo->packs[i - 1]);
899 		if (err)
900 			return err;
901 		memmove(&repo->packs[1], &repo->packs[0],
902 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
903 		i = 0;
904 	}
905 
906 	pack = &repo->packs[i];
907 
908 	pack->path_packfile = strdup(path_packfile);
909 	if (pack->path_packfile == NULL) {
910 		err = got_error_from_errno();
911 		goto done;
912 	}
913 
914 	err = open_packfile(&pack->fd, path_packfile, packidx);
915 	if (err)
916 		goto done;
917 
918 	err = got_pack_get_packfile_size(&pack->filesize, path_packfile);
919 	if (err)
920 		goto done;
921 
922 #ifndef GOT_PACK_NO_MMAP
923 	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
924 	    pack->fd, 0);
925 	if (pack->map == MAP_FAILED)
926 		pack->map = NULL; /* fall back to read(2) */
927 #endif
928 done:
929 	if (err) {
930 		if (pack) {
931 			free(pack->path_packfile);
932 			memset(pack, 0, sizeof(*pack));
933 		}
934 	} else if (packp)
935 		*packp = pack;
936 	return err;
937 }
938 
939 struct got_pack *
940 got_repo_get_cached_pack(struct got_repository *repo, const char *path_packfile)
941 {
942 	struct got_pack *pack = NULL;
943 	int i;
944 
945 	for (i = 0; i < nitems(repo->packs); i++) {
946 		pack = &repo->packs[i];
947 		if (pack->path_packfile == NULL)
948 			break;
949 		if (strcmp(pack->path_packfile, path_packfile) == 0)
950 			return pack;
951 	}
952 
953 	return NULL;
954 }