Game of Trees Repos

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Date:: Sun Jul 8 17:08:12 2018 UTC
Message:: don't verify pack index SHA1 upon regular access
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/stat.h>
19 #include <sys/queue.h>
20 #include <sys/mman.h>
21 
22 #include <dirent.h>
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <zlib.h>
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_opentemp.h"
38 
39 #include "got_lib_sha1.h"
40 #include "got_lib_pack.h"
41 #include "got_lib_path.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_zbuf.h"
44 #include "got_lib_object.h"
45 #include "got_lib_repository.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #define GOT_PACK_PREFIX		"pack-"
52 #define GOT_PACKFILE_SUFFIX	".pack"
53 #define GOT_PACKIDX_SUFFIX		".idx"
54 #define GOT_PACKFILE_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
55 				SHA1_DIGEST_STRING_LENGTH - 1 + \
56 				strlen(GOT_PACKFILE_SUFFIX))
57 #define GOT_PACKIDX_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
58 				SHA1_DIGEST_STRING_LENGTH - 1 + \
59 				strlen(GOT_PACKIDX_SUFFIX))
60 
61 #ifndef MIN
62 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
63 #endif
64 
65 static const struct got_error *
66 verify_fanout_table(uint32_t *fanout_table)
67 {
68 	int i;
69 
70 	for (i = 0; i < 0xff - 1; i++) {
71 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
72 			return got_error(GOT_ERR_BAD_PACKIDX);
73 	}
74 
75 	return NULL;
76 }
77 
78 static const struct got_error *
79 get_packfile_size(size_t *size, const char *path)
80 {
81 	struct stat sb;
82 	char *dot;
83 
84 	*size = 0;
85 
86 	dot = strrchr(path, '.');
87 	if (dot == NULL)
88 		return got_error(GOT_ERR_BAD_PATH);
89 
90 	/* Path must point to a pack index or to a pack file. */
91 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
92 		const struct got_error *err = NULL;
93 		char *path_pack;
94 		char base_path[PATH_MAX];
95 
96 		/* Convert pack index path to pack file path. */
97 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
98 			return got_error(GOT_ERR_NO_SPACE);
99 		dot = strrchr(base_path, '.');
100 		if (dot == NULL)
101 			return got_error(GOT_ERR_BAD_PATH);
102 		*dot = '\0';
103 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
104 			return got_error_from_errno();
105 
106 		if (stat(path_pack, &sb) != 0)
107 			err = got_error_from_errno();
108 		free(path_pack);
109 		if (err)
110 			return err;
111 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
112 		if (stat(path, &sb) != 0)
113 			return got_error_from_errno();
114 	} else
115 		return got_error(GOT_ERR_BAD_PATH);
116 
117 	*size = sb.st_size;
118 	return 0;
119 }
120 
121 const struct got_error *
122 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
123 {
124 	struct got_packidx *p;
125 	struct got_packidx_v2_hdr *h;
126 	const struct got_error *err = NULL;
127 	size_t nobj, len_fanout, len_ids, offset, remain;
128 	SHA1_CTX ctx;
129 	uint8_t sha1[SHA1_DIGEST_LENGTH];
130 
131 	*packidx = NULL;
132 
133 	SHA1Init(&ctx);
134 
135 	p = calloc(1, sizeof(*p));
136 	if (p == NULL)
137 		return got_error_from_errno();
138 
139 	p->fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
140 	if (p->fd == -1)
141 		return got_error_from_errno();
142 
143 	err = get_packfile_size(&p->len, path);
144 	if (err) {
145 		close(p->fd);
146 		free(p);
147 		return err;
148 	}
149 	if (p->len < sizeof(p->hdr)) {
150 		err = got_error(GOT_ERR_BAD_PACKIDX);
151 		close(p->fd);
152 		free(p);
153 		return err;
154 	}
155 
156 	p->path_packidx = strdup(path);
157 	if (p->path_packidx == NULL) {
158 		err = got_error_from_errno();
159 		goto done;
160 	}
161 
162 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
163 	if (p->map == MAP_FAILED) {
164 		err = got_error_from_errno();
165 		goto done;
166 	}
167 	h = &p->hdr;
168 	offset = 0;
169 	remain = p->len;
170 
171 	if (remain < sizeof(*h->magic)) {
172 		err = got_error(GOT_ERR_BAD_PACKIDX);
173 		goto done;
174 	}
175 	h->magic = (uint32_t *)(p->map + offset);
176 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
177 		err = got_error(GOT_ERR_BAD_PACKIDX);
178 		goto done;
179 	}
180 	offset += sizeof(*h->magic);
181 	remain -= sizeof(*h->magic);
182 
183 	if (verify)
184 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
185 
186 	if (remain < sizeof(*h->version)) {
187 		err = got_error(GOT_ERR_BAD_PACKIDX);
188 		goto done;
189 	}
190 	h->version = (uint32_t *)(p->map + offset);
191 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
192 		err = got_error(GOT_ERR_BAD_PACKIDX);
193 		goto done;
194 	}
195 	offset += sizeof(*h->version);
196 	remain -= sizeof(*h->version);
197 
198 	if (verify)
199 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
200 
201 	len_fanout =
202 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
203 	if (remain < len_fanout) {
204 		err = got_error(GOT_ERR_BAD_PACKIDX);
205 		goto done;
206 	}
207 	h->fanout_table = (uint32_t *)(p->map + offset);
208 	err = verify_fanout_table(h->fanout_table);
209 	if (err)
210 		goto done;
211 	if (verify)
212 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
213 	offset += len_fanout;
214 	remain -= len_fanout;
215 
216 	nobj = betoh32(h->fanout_table[0xff]);
217 	len_ids = nobj * sizeof(*h->sorted_ids);
218 	if (len_ids <= nobj || len_ids > remain) {
219 		err = got_error(GOT_ERR_BAD_PACKIDX);
220 		goto done;
221 	}
222 	h->sorted_ids =
223 	    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
224 	if (verify)
225 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
226 	offset += len_ids;
227 	remain -= len_ids;
228 
229 	if (remain < nobj * sizeof(*h->crc32)) {
230 		err = got_error(GOT_ERR_BAD_PACKIDX);
231 		goto done;
232 	}
233 	h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
234 	if (verify)
235 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
236 	remain -= nobj * sizeof(*h->crc32);
237 	offset += nobj * sizeof(*h->crc32);
238 
239 	if (remain < nobj * sizeof(*h->offsets)) {
240 		err = got_error(GOT_ERR_BAD_PACKIDX);
241 		goto done;
242 	}
243 	h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
244 	if (verify)
245 		SHA1Update(&ctx, (uint8_t *)h->offsets,
246 		    nobj * sizeof(*h->offsets));
247 	remain -= nobj * sizeof(*h->offsets);
248 	offset += nobj * sizeof(*h->offsets);
249 
250 	/* Large file offsets are contained only in files > 2GB. */
251 	if (p->len <= 0x80000000)
252 		goto checksum;
253 
254 	if (remain < nobj * sizeof(*h->large_offsets)) {
255 		err = got_error(GOT_ERR_BAD_PACKIDX);
256 		goto done;
257 	}
258 	h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
259 	if (verify)
260 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
261 		    nobj * sizeof(*h->large_offsets));
262 	remain -= nobj * sizeof(*h->large_offsets);
263 	offset += nobj * sizeof(*h->large_offsets);
264 
265 checksum:
266 	if (remain < sizeof(*h->trailer)) {
267 		err = got_error(GOT_ERR_BAD_PACKIDX);
268 		goto done;
269 	}
270 	h->trailer =
271 	    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
272 	if (verify) {
273 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
274 		SHA1Final(sha1, &ctx);
275 		if (memcmp(h->trailer->packidx_sha1, sha1,
276 		    SHA1_DIGEST_LENGTH) != 0)
277 			err = got_error(GOT_ERR_PACKIDX_CSUM);
278 	}
279 done:
280 	if (err)
281 		got_packidx_close(p);
282 	else
283 		*packidx = p;
284 	return err;
285 }
286 
287 const struct got_error *
288 got_packidx_close(struct got_packidx *packidx)
289 {
290 	const struct got_error *err = NULL;
291 
292 	free(packidx->path_packidx);
293 	if (packidx->map != NULL && packidx->map != MAP_FAILED) {
294 		if (munmap(packidx->map, packidx->len) == -1)
295 			err = got_error_from_errno();
296 	}
297 	close(packidx->fd);
298 	free(packidx);
299 
300 	return err;
301 }
302 
303 static int
304 is_packidx_filename(const char *name, size_t len)
305 {
306 	if (len != GOT_PACKIDX_NAMELEN)
307 		return 0;
308 
309 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
310 		return 0;
311 
312 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
313 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
314 		return 0;
315 
316 	return 1;
317 }
318 
319 static off_t
320 get_object_offset(struct got_packidx *packidx, int idx)
321 {
322 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
323 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
324 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
325 		uint64_t loffset;
326 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
327 		if (idx < 0 || idx > totobj ||
328 		    packidx->hdr.large_offsets == NULL)
329 			return -1;
330 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
331 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
332 	}
333 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
334 }
335 
336 static int
337 get_object_idx(struct got_packidx *packidx, struct got_object_id *id,
338     struct got_repository *repo)
339 {
340 	u_int8_t id0 = id->sha1[0];
341 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
342 	int left = 0, right = totobj - 1;
343 
344 	if (id0 > 0)
345 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
346 
347 	while (left <= right) {
348 		struct got_packidx_object_id *oid;
349 		int i, cmp;
350 
351 		i = ((left + right) / 2);
352 		oid = &packidx->hdr.sorted_ids[i];
353 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
354 		if (cmp == 0)
355 			return i;
356 		else if (cmp > 0)
357 			left = i + 1;
358 		else if (cmp < 0)
359 			right = i - 1;
360 	}
361 
362 	return -1;
363 }
364 
365 static const struct got_error *
366 cache_packidx(struct got_packidx *packidx, struct got_repository *repo)
367 {
368 	const struct got_error *err = NULL;
369 	int i;
370 
371 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
372 		if (repo->packidx_cache[i] == NULL)
373 			break;
374 	}
375 
376 	if (i == nitems(repo->packidx_cache)) {
377 		err = got_packidx_close(repo->packidx_cache[i - 1]);
378 		if (err)
379 			return err;
380 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
381 		    sizeof(repo->packidx_cache) -
382 		    sizeof(repo->packidx_cache[0]));
383 		i = 0;
384 	}
385 
386 	repo->packidx_cache[i] = packidx;
387 	return NULL;
388 }
389 
390 static const struct got_error *
391 search_packidx(struct got_packidx **packidx, int *idx,
392     struct got_repository *repo, struct got_object_id *id)
393 {
394 	const struct got_error *err;
395 	char *path_packdir;
396 	DIR *packdir;
397 	struct dirent *dent;
398 	char *path_packidx;
399 	int i;
400 
401 	/* Search pack index cache. */
402 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
403 		if (repo->packidx_cache[i] == NULL)
404 			break;
405 		*idx = get_object_idx(repo->packidx_cache[i], id, repo);
406 		if (*idx != -1) {
407 			*packidx = repo->packidx_cache[i];
408 			return NULL;
409 		}
410 	}
411 	/* No luck. Search the filesystem. */
412 
413 	path_packdir = got_repo_get_path_objects_pack(repo);
414 	if (path_packdir == NULL)
415 		return got_error_from_errno();
416 
417 	packdir = opendir(path_packdir);
418 	if (packdir == NULL) {
419 		err = got_error_from_errno();
420 		goto done;
421 	}
422 
423 	while ((dent = readdir(packdir)) != NULL) {
424 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
425 			continue;
426 
427 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
428 		    dent->d_name) == -1) {
429 			err = got_error_from_errno();
430 			goto done;
431 		}
432 
433 		err = got_packidx_open(packidx, path_packidx, 0);
434 		free(path_packidx);
435 		if (err)
436 			goto done;
437 
438 		*idx = get_object_idx(*packidx, id, repo);
439 		if (*idx != -1) {
440 			err = NULL; /* found the object */
441 			err = cache_packidx(*packidx, repo);
442 			goto done;
443 		}
444 
445 		err = got_packidx_close(*packidx);
446 		*packidx = NULL;
447 		if (err)
448 			goto done;
449 	}
450 
451 	err = got_error(GOT_ERR_NO_OBJ);
452 done:
453 	free(path_packdir);
454 	if (packdir && closedir(packdir) != 0 && err == 0)
455 		err = got_error_from_errno();
456 	return err;
457 }
458 
459 static const struct got_error *
460 get_packfile_path(char **path_packfile, struct got_repository *repo,
461     struct got_packidx *packidx)
462 {
463 	size_t size;
464 
465 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
466 	size = strlen(packidx->path_packidx) + 2;
467 	if (size < GOT_PACKFILE_NAMELEN + 1)
468 		return got_error(GOT_ERR_BAD_PATH);
469 
470 	*path_packfile = calloc(size, sizeof(**path_packfile));
471 	if (*path_packfile == NULL)
472 		return got_error_from_errno();
473 
474 	/* Copy up to and excluding ".idx". */
475 	if (strlcpy(*path_packfile, packidx->path_packidx,
476 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
477 		return got_error(GOT_ERR_NO_SPACE);
478 
479 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
480 		return got_error(GOT_ERR_NO_SPACE);
481 
482 	return NULL;
483 }
484 
485 const struct got_error *
486 read_packfile_hdr(int fd, struct got_packidx *packidx)
487 {
488 	const struct got_error *err = NULL;
489 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
490 	struct got_packfile_hdr hdr;
491 	ssize_t n;
492 
493 	n = read(fd, &hdr, sizeof(hdr));
494 	if (n < 0)
495 		return got_error_from_errno();
496 	if (n != sizeof(hdr))
497 		return got_error(GOT_ERR_BAD_PACKFILE);
498 
499 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
500 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
501 	    betoh32(hdr.nobjects) != totobj)
502 		err = got_error(GOT_ERR_BAD_PACKFILE);
503 
504 	return err;
505 }
506 
507 static const struct got_error *
508 open_packfile(int *fd, const char *path_packfile,
509     struct got_repository *repo, struct got_packidx *packidx)
510 {
511 	const struct got_error *err = NULL;
512 
513 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
514 	if (*fd == -1)
515 		return got_error_from_errno();
516 
517 	if (packidx) {
518 		err = read_packfile_hdr(*fd, packidx);
519 		if (err) {
520 			close(*fd);
521 			*fd = -1;
522 		}
523 	}
524 	return err;
525 }
526 
527 void
528 got_pack_close(struct got_pack *pack)
529 {
530 	close(pack->fd);
531 	pack->fd = -1;
532 	free(pack->path_packfile);
533 	pack->path_packfile = NULL;
534 	pack->filesize = 0;
535 }
536 
537 static const struct got_error *
538 cache_pack(struct got_pack **packp, const char *path_packfile,
539     struct got_packidx *packidx, struct got_repository *repo)
540 {
541 	const struct got_error *err = NULL;
542 	struct got_pack *pack = NULL;
543 	int i;
544 
545 	if (packp)
546 		*packp = NULL;
547 
548 	for (i = 0; i < nitems(repo->packs); i++) {
549 		pack = &repo->packs[i];
550 		if (pack->path_packfile == NULL)
551 			break;
552 		if (strcmp(pack->path_packfile, path_packfile) == 0)
553 			return NULL;
554 	}
555 
556 	if (i == nitems(repo->packs) - 1) {
557 		got_pack_close(&repo->packs[i - 1]);
558 		memmove(&repo->packs[1], &repo->packs[0],
559 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
560 		i = 0;
561 	}
562 
563 	pack = &repo->packs[i];
564 
565 	pack->path_packfile = strdup(path_packfile);
566 	if (pack->path_packfile == NULL) {
567 		err = got_error_from_errno();
568 		goto done;
569 	}
570 
571 	err = open_packfile(&pack->fd, path_packfile, repo, packidx);
572 	if (err)
573 		goto done;
574 
575 	err = get_packfile_size(&pack->filesize, path_packfile);
576 done:
577 	if (err) {
578 		if (pack) {
579 			free(pack->path_packfile);
580 			memset(pack, 0, sizeof(*pack));
581 		}
582 	} else if (packp)
583 		*packp = pack;
584 	return err;
585 }
586 
587 struct got_pack *
588 get_cached_pack(const char *path_packfile, struct got_repository *repo)
589 {
590 	struct got_pack *pack = NULL;
591 	int i;
592 
593 	for (i = 0; i < nitems(repo->packs); i++) {
594 		pack = &repo->packs[i];
595 		if (pack->path_packfile == NULL)
596 			break;
597 		if (strcmp(pack->path_packfile, path_packfile) == 0)
598 			return pack;
599 	}
600 
601 	return NULL;
602 }
603 
604 static const struct got_error *
605 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len, int fd)
606 {
607 	uint8_t t = 0;
608 	uint64_t s = 0;
609 	uint8_t sizeN;
610 	ssize_t n;
611 	int i = 0;
612 
613 	do {
614 		/* We do not support size values which don't fit in 64 bit. */
615 		if (i > 9)
616 			return got_error(GOT_ERR_NO_SPACE);
617 
618 		n = read(fd, &sizeN, sizeof(sizeN));
619 		if (n < 0)
620 			return got_error_from_errno();
621 		if (n != sizeof(sizeN))
622 			return got_error(GOT_ERR_BAD_PACKFILE);
623 
624 		if (i == 0) {
625 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
626 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
627 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
628 		} else {
629 			size_t shift = 4 + 7 * (i - 1);
630 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
631 		}
632 		i++;
633 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
634 
635 	*type = t;
636 	*size = s;
637 	*len = i * sizeof(sizeN);
638 	return NULL;
639 }
640 
641 static const struct got_error *
642 open_plain_object(struct got_object **obj, const char *path_packfile,
643     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
644 {
645 	*obj = calloc(1, sizeof(**obj));
646 	if (*obj == NULL)
647 		return got_error_from_errno();
648 
649 	(*obj)->path_packfile = strdup(path_packfile);
650 	if ((*obj)->path_packfile == NULL) {
651 		const struct got_error *err = got_error_from_errno();
652 		free(*obj);
653 		*obj = NULL;
654 		return err;
655 	}
656 
657 	(*obj)->type = type;
658 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
659 	(*obj)->hdrlen = 0;
660 	(*obj)->size = size;
661 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
662 	(*obj)->pack_offset = offset;
663 
664 	return NULL;
665 }
666 
667 static const struct got_error *
668 parse_negative_offset(int64_t *offset, size_t *len, int fd)
669 {
670 	int64_t o = 0;
671 	uint8_t offN;
672 	ssize_t n;
673 	int i = 0;
674 
675 	do {
676 		/* We do not support offset values which don't fit in 64 bit. */
677 		if (i > 8)
678 			return got_error(GOT_ERR_NO_SPACE);
679 
680 		n = read(fd, &offN, sizeof(offN));
681 		if (n < 0)
682 			return got_error_from_errno();
683 		if (n != sizeof(offN))
684 			return got_error(GOT_ERR_BAD_PACKFILE);
685 
686 		if (i == 0)
687 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
688 		else {
689 			o++;
690 			o <<= 7;
691 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
692 		}
693 		i++;
694 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
695 
696 	*offset = o;
697 	*len = i * sizeof(offN);
698 	return NULL;
699 }
700 
701 static const struct got_error *
702 parse_offset_delta(off_t *base_offset, int fd, off_t offset)
703 {
704 	const struct got_error *err;
705 	int64_t negoffset;
706 	size_t negofflen;
707 
708 	err = parse_negative_offset(&negoffset, &negofflen, fd);
709 	if (err)
710 		return err;
711 
712 	/* Compute the base object's offset (must be in the same pack file). */
713 	*base_offset = (offset - negoffset);
714 	if (*base_offset <= 0)
715 		return got_error(GOT_ERR_BAD_PACKFILE);
716 
717 	return NULL;
718 }
719 
720 static const struct got_error *
721 resolve_delta_chain(struct got_delta_chain *, struct got_repository *,
722     struct got_packidx *, struct got_pack *, off_t, size_t, int,
723     size_t, unsigned int);
724 
725 static const struct got_error *
726 add_delta(struct got_delta_chain *deltas, const char *path_packfile,
727     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
728     size_t delta_data_offset, uint8_t *delta_buf, size_t delta_len)
729 {
730 	struct got_delta *delta;
731 
732 	delta = got_delta_open(path_packfile, delta_offset, tslen,
733 	    delta_type, delta_size, delta_data_offset, delta_buf,
734 	    delta_len);
735 	if (delta == NULL)
736 		return got_error_from_errno();
737 	/* delta is freed in got_object_close() */
738 	deltas->nentries++;
739 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
740 	return NULL;
741 }
742 
743 static const struct got_error *
744 resolve_offset_delta(struct got_delta_chain *deltas,
745     struct got_repository *repo, struct got_packidx *packidx,
746     struct got_pack *pack, off_t delta_offset, size_t tslen,
747     int delta_type, size_t delta_size, unsigned int recursion)
748 
749 {
750 	const struct got_error *err;
751 	off_t base_offset;
752 	uint8_t base_type;
753 	uint64_t base_size;
754 	size_t base_tslen;
755 	off_t delta_data_offset;
756 	uint8_t *delta_buf;
757 	size_t delta_len;
758 
759 	err = parse_offset_delta(&base_offset, pack->fd, delta_offset);
760 	if (err)
761 		return err;
762 
763 	delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
764 	if (delta_data_offset == -1)
765 		return got_error_from_errno();
766 
767 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
768 	if (err)
769 		return err;
770 
771 	err = add_delta(deltas, pack->path_packfile, delta_offset, tslen,
772 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
773 	if (err)
774 		return err;
775 
776 	/* An offset delta must be in the same packfile. */
777 	if (base_offset >= pack->filesize)
778 		return got_error(GOT_ERR_PACK_OFFSET);
779 	if (lseek(pack->fd, base_offset, SEEK_SET) == -1)
780 		return got_error_from_errno();
781 
782 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
783 	    pack->fd);
784 	if (err)
785 		return err;
786 
787 	return resolve_delta_chain(deltas, repo, packidx, pack, base_offset,
788 	    base_tslen, base_type, base_size, recursion - 1);
789 }
790 
791 static const struct got_error *
792 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
793     struct got_packidx *packidx, struct got_pack *pack,
794     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
795     unsigned int recursion)
796 {
797 	const struct got_error *err;
798 	struct got_object_id id;
799 	int idx;
800 	off_t base_offset;
801 	uint8_t base_type;
802 	uint64_t base_size;
803 	size_t base_tslen;
804 	ssize_t n;
805 	off_t delta_data_offset;
806 	uint8_t *delta_buf;
807 	size_t delta_len;
808 
809 	n = read(pack->fd, &id, sizeof(id));
810 	if (n < 0)
811 		return got_error_from_errno();
812 	if (n != sizeof(id))
813 		return got_error(GOT_ERR_BAD_PACKFILE);
814 
815 	delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
816 	if (delta_data_offset == -1)
817 		return got_error_from_errno();
818 
819 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
820 	if (err)
821 		return err;
822 
823 	err = add_delta(deltas, pack->path_packfile, delta_offset, tslen,
824 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
825 	if (err)
826 		return err;
827 
828 	/* Delta base must be in the same pack file. */
829 	idx = get_object_idx(packidx, &id, repo);
830 	if (idx == -1)
831 		return got_error(GOT_ERR_BAD_PACKFILE);
832 
833 	base_offset = get_object_offset(packidx, idx);
834 	if (base_offset == (uint64_t)-1) {
835 		return got_error(GOT_ERR_BAD_PACKIDX);
836 	}
837 
838 	if (base_offset >= pack->filesize) {
839 		err = got_error(GOT_ERR_PACK_OFFSET);
840 		goto done;
841 	}
842 	if (lseek(pack->fd, base_offset, SEEK_SET) == -1) {
843 		err = got_error_from_errno();
844 		goto done;
845 	}
846 
847 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
848 	    pack->fd);
849 	if (err)
850 		goto done;
851 
852 	err = resolve_delta_chain(deltas, repo, packidx, pack, base_offset,
853 	    base_tslen, base_type, base_size, recursion - 1);
854 done:
855 	return err;
856 }
857 
858 static const struct got_error *
859 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
860     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
861     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
862 {
863 	const struct got_error *err = NULL;
864 
865 	if (--recursion == 0)
866 		return got_error(GOT_ERR_RECURSION);
867 
868 	switch (delta_type) {
869 	case GOT_OBJ_TYPE_COMMIT:
870 	case GOT_OBJ_TYPE_TREE:
871 	case GOT_OBJ_TYPE_BLOB:
872 	case GOT_OBJ_TYPE_TAG:
873 		/* Plain types are the final delta base. Recursion ends. */
874 		err = add_delta(deltas, pack->path_packfile, delta_offset,
875 		    tslen, delta_type, delta_size, 0, NULL, 0);
876 		break;
877 	case GOT_OBJ_TYPE_OFFSET_DELTA:
878 		err = resolve_offset_delta(deltas, repo, packidx, pack,
879 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
880 		break;
881 	case GOT_OBJ_TYPE_REF_DELTA:
882 		err = resolve_ref_delta(deltas, repo, packidx, pack,
883 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
884 		break;
885 	default:
886 		return got_error(GOT_ERR_OBJ_TYPE);
887 	}
888 
889 	return err;
890 }
891 
892 static const struct got_error *
893 open_delta_object(struct got_object **obj, struct got_repository *repo,
894     struct got_packidx *packidx, struct got_pack *pack,
895     struct got_object_id *id, off_t offset, size_t tslen,
896     int delta_type, size_t delta_size)
897 {
898 	const struct got_error *err = NULL;
899 	int resolved_type;
900 
901 	*obj = calloc(1, sizeof(**obj));
902 	if (*obj == NULL)
903 		return got_error_from_errno();
904 
905 	(*obj)->flags = 0;
906 	(*obj)->hdrlen = 0;
907 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
908 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
909 	(*obj)->pack_offset = offset + tslen;
910 
911 	(*obj)->path_packfile = strdup(pack->path_packfile);
912 	if ((*obj)->path_packfile == NULL) {
913 		err = got_error_from_errno();
914 		goto done;
915 	}
916 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
917 
918 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
919 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
920 
921 	err = resolve_delta_chain(&(*obj)->deltas, repo, packidx, pack, offset,
922 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
923 	if (err)
924 		goto done;
925 
926 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
927 	if (err)
928 		goto done;
929 	(*obj)->type = resolved_type;
930 
931 done:
932 	if (err) {
933 		got_object_close(*obj);
934 		*obj = NULL;
935 	}
936 	return err;
937 }
938 
939 static const struct got_error *
940 open_packed_object(struct got_object **obj, struct got_repository *repo,
941     struct got_packidx *packidx, int idx, struct got_object_id *id)
942 {
943 	const struct got_error *err = NULL;
944 	off_t offset;
945 	char *path_packfile;
946 	struct got_pack *pack;
947 	uint8_t type;
948 	uint64_t size;
949 	size_t tslen;
950 
951 	*obj = NULL;
952 
953 	offset = get_object_offset(packidx, idx);
954 	if (offset == (uint64_t)-1)
955 		return got_error(GOT_ERR_BAD_PACKIDX);
956 
957 	err = get_packfile_path(&path_packfile, repo, packidx);
958 	if (err)
959 		return err;
960 
961 	pack = get_cached_pack(path_packfile, repo);
962 	if (pack == NULL) {
963 		err = cache_pack(&pack, path_packfile, packidx, repo);
964 		if (err)
965 			goto done;
966 	}
967 
968 	if (offset >= pack->filesize) {
969 		err = got_error(GOT_ERR_PACK_OFFSET);
970 		goto done;
971 	}
972 	if (lseek(pack->fd, offset, SEEK_SET) == -1) {
973 		err = got_error_from_errno();
974 		goto done;
975 	}
976 
977 	err = parse_object_type_and_size(&type, &size, &tslen, pack->fd);
978 	if (err)
979 		goto done;
980 
981 	switch (type) {
982 	case GOT_OBJ_TYPE_COMMIT:
983 	case GOT_OBJ_TYPE_TREE:
984 	case GOT_OBJ_TYPE_BLOB:
985 	case GOT_OBJ_TYPE_TAG:
986 		err = open_plain_object(obj, path_packfile, id, type,
987 		    offset + tslen, size);
988 		break;
989 
990 	case GOT_OBJ_TYPE_OFFSET_DELTA:
991 	case GOT_OBJ_TYPE_REF_DELTA:
992 		err = open_delta_object(obj, repo, packidx, pack, id, offset,
993 		    tslen, type, size);
994 		break;
995 
996 	default:
997 		err = got_error(GOT_ERR_OBJ_TYPE);
998 		goto done;
999 	}
1000 done:
1001 	free(path_packfile);
1002 	return err;
1003 }
1004 
1005 const struct got_error *
1006 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1007     struct got_repository *repo)
1008 {
1009 	const struct got_error *err = NULL;
1010 	struct got_packidx *packidx = NULL;
1011 	int idx;
1012 
1013 	err = search_packidx(&packidx, &idx, repo, id);
1014 	if (err)
1015 		return err;
1016 
1017 	err = open_packed_object(obj, repo, packidx, idx, id);
1018 	if (err)
1019 		return err;
1020 
1021 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1022 	return err;
1023 }
1024 
1025 static const struct got_error *
1026 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1027 {
1028 	struct got_delta *delta;
1029 	uint64_t base_size = 0, result_size = 0;
1030 
1031 	*max_size = 0;
1032 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1033 		/* Plain object types are the delta base. */
1034 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1035 		    delta->type != GOT_OBJ_TYPE_TREE &&
1036 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1037 		    delta->type != GOT_OBJ_TYPE_TAG) {
1038 			const struct got_error *err;
1039 			err = got_delta_get_sizes(&base_size, &result_size,
1040 			    delta->delta_buf, delta->delta_len);
1041 			if (err)
1042 				return err;
1043 		} else
1044 			base_size = delta->size;
1045 		if (base_size > *max_size)
1046 			*max_size = base_size;
1047 		if (result_size > *max_size)
1048 			*max_size = result_size;
1049 	}
1050 
1051 	return NULL;
1052 }
1053 
1054 static const struct got_error *
1055 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1056     FILE *outfile, struct got_repository *repo)
1057 {
1058 	const struct got_error *err = NULL;
1059 	struct got_delta *delta;
1060 	FILE *base_file = NULL, *accum_file = NULL;
1061 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1062 	size_t accum_size = 0;
1063 	uint64_t max_size;
1064 	int n = 0;
1065 
1066 	*result_size = 0;
1067 
1068 	if (SIMPLEQ_EMPTY(&deltas->entries))
1069 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1070 
1071 	/* We process small enough files entirely in memory for speed. */
1072 	err = get_delta_chain_max_size(&max_size, deltas);
1073 	if (err)
1074 		return err;
1075 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1076 		accum_buf = malloc(max_size);
1077 		if (accum_buf == NULL)
1078 			return got_error_from_errno();
1079 	} else {
1080 		base_file = got_opentemp();
1081 		if (base_file == NULL)
1082 			return got_error_from_errno();
1083 
1084 		accum_file = got_opentemp();
1085 		if (accum_file == NULL) {
1086 			err = got_error_from_errno();
1087 			fclose(base_file);
1088 			return err;
1089 		}
1090 	}
1091 
1092 	/* Deltas are ordered in ascending order. */
1093 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1094 		if (n == 0) {
1095 			struct got_pack *pack;
1096 			size_t base_len;
1097 			off_t delta_data_offset;
1098 
1099 			/* Plain object types are the delta base. */
1100 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1101 			    delta->type != GOT_OBJ_TYPE_TREE &&
1102 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1103 			    delta->type != GOT_OBJ_TYPE_TAG) {
1104 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1105 				goto done;
1106 			}
1107 
1108 			pack = get_cached_pack(delta->path_packfile, repo);
1109 			if (pack == NULL) {
1110 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1111 				goto done;
1112 			}
1113 
1114 			delta_data_offset = delta->offset + delta->tslen;
1115 			if (delta_data_offset >= pack->filesize) {
1116 				err = got_error(GOT_ERR_PACK_OFFSET);
1117 				goto done;
1118 			}
1119 			if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1120 			    == -1) {
1121 				err = got_error_from_errno();
1122 				goto done;
1123 			}
1124 			if (base_file)
1125 				err = got_inflate_to_file_fd(&base_len,
1126 				    pack->fd, base_file);
1127 			else {
1128 				err = got_inflate_to_mem_fd(&base_buf,
1129 				    &base_len, pack->fd);
1130 				if (base_len < max_size) {
1131 					uint8_t *p;
1132 					p = reallocarray(base_buf, 1, max_size);
1133 					if (p == NULL) {
1134 						err = got_error_from_errno();
1135 						goto done;
1136 					}
1137 					base_buf = p;
1138 				}
1139 			}
1140 			if (err)
1141 				goto done;
1142 			n++;
1143 			if (base_file)
1144 				rewind(base_file);
1145 			continue;
1146 		}
1147 
1148 		if (base_buf) {
1149 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1150 			    delta->delta_len, accum_buf, &accum_size);
1151 			n++;
1152 		} else {
1153 			err = got_delta_apply(base_file, delta->delta_buf,
1154 			    delta->delta_len,
1155 			    /* Final delta application writes to output file. */
1156 			    ++n < deltas->nentries ? accum_file : outfile,
1157 			    &accum_size);
1158 		}
1159 		if (err)
1160 			goto done;
1161 
1162 		if (n < deltas->nentries) {
1163 			/* Accumulated delta becomes the new base. */
1164 			if (base_buf) {
1165 				uint8_t *tmp = accum_buf;
1166 				accum_buf = base_buf;
1167 				base_buf = tmp;
1168 			} else {
1169 				FILE *tmp = accum_file;
1170 				accum_file = base_file;
1171 				base_file = tmp;
1172 				rewind(base_file);
1173 				rewind(accum_file);
1174 			}
1175 		}
1176 	}
1177 
1178 done:
1179 	free(base_buf);
1180 	if (accum_buf) {
1181 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1182 		free(accum_buf);
1183 		if (len != accum_size)
1184 			return got_ferror(outfile, GOT_ERR_IO);
1185 	}
1186 	if (base_file)
1187 		fclose(base_file);
1188 	if (accum_file)
1189 		fclose(accum_file);
1190 	rewind(outfile);
1191 	if (err == NULL)
1192 		*result_size = accum_size;
1193 	return err;
1194 }
1195 
1196 static const struct got_error *
1197 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1198     struct got_delta_chain *deltas, struct got_repository *repo)
1199 {
1200 	const struct got_error *err = NULL;
1201 	struct got_delta *delta;
1202 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1203 	size_t accum_size;
1204 	uint64_t max_size;
1205 	int n = 0;
1206 
1207 	*outbuf = NULL;
1208 	*outlen = 0;
1209 
1210 	if (SIMPLEQ_EMPTY(&deltas->entries))
1211 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1212 
1213 	err = get_delta_chain_max_size(&max_size, deltas);
1214 	if (err)
1215 		return err;
1216 	accum_buf = malloc(max_size);
1217 	if (accum_buf == NULL)
1218 		return got_error_from_errno();
1219 
1220 	/* Deltas are ordered in ascending order. */
1221 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1222 		if (n == 0) {
1223 			struct got_pack *pack;
1224 			size_t base_len;
1225 			size_t delta_data_offset;
1226 
1227 			/* Plain object types are the delta base. */
1228 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1229 			    delta->type != GOT_OBJ_TYPE_TREE &&
1230 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1231 			    delta->type != GOT_OBJ_TYPE_TAG) {
1232 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1233 				goto done;
1234 			}
1235 
1236 			pack = get_cached_pack(delta->path_packfile, repo);
1237 			if (pack == NULL) {
1238 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1239 				goto done;
1240 			}
1241 
1242 			delta_data_offset = delta->offset + delta->tslen;
1243 			if (delta_data_offset >= pack->filesize) {
1244 				err = got_error(GOT_ERR_PACK_OFFSET);
1245 				goto done;
1246 			}
1247 			if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1248 			    == -1) {
1249 				err = got_error_from_errno();
1250 				goto done;
1251 			}
1252 			err = got_inflate_to_mem_fd(&base_buf, &base_len,
1253 			    pack->fd);
1254 			if (base_len < max_size) {
1255 				uint8_t *p;
1256 				p = reallocarray(base_buf, 1, max_size);
1257 				if (p == NULL) {
1258 					err = got_error_from_errno();
1259 					goto done;
1260 				}
1261 				base_buf = p;
1262 			}
1263 			if (err)
1264 				goto done;
1265 			n++;
1266 			continue;
1267 		}
1268 
1269 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1270 		    delta->delta_len, accum_buf, &accum_size);
1271 		n++;
1272 		if (err)
1273 			goto done;
1274 
1275 		if (n < deltas->nentries) {
1276 			/* Accumulated delta becomes the new base. */
1277 			uint8_t *tmp = accum_buf;
1278 			accum_buf = base_buf;
1279 			base_buf = tmp;
1280 		}
1281 	}
1282 
1283 done:
1284 	free(base_buf);
1285 	if (err) {
1286 		free(accum_buf);
1287 		*outbuf = NULL;
1288 		*outlen = 0;
1289 	} else {
1290 		*outbuf = accum_buf;
1291 		*outlen = accum_size;
1292 	}
1293 	return err;
1294 }
1295 
1296 const struct got_error *
1297 got_packfile_extract_object(FILE **f, struct got_object *obj,
1298     struct got_repository *repo)
1299 {
1300 	const struct got_error *err = NULL;
1301 
1302 	*f = NULL;
1303 
1304 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1305 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1306 
1307 	*f = got_opentemp();
1308 	if (*f == NULL) {
1309 		err = got_error_from_errno();
1310 		goto done;
1311 	}
1312 
1313 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1314 		struct got_pack *pack;
1315 
1316 		pack = get_cached_pack(obj->path_packfile, repo);
1317 		if (pack == NULL) {
1318 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1319 			if (err)
1320 				goto done;
1321 		}
1322 
1323 		if (obj->pack_offset >= pack->filesize) {
1324 			err = got_error(GOT_ERR_PACK_OFFSET);
1325 			goto done;
1326 		}
1327 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1328 			err = got_error_from_errno();
1329 			goto done;
1330 		}
1331 
1332 		err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1333 	} else
1334 		err = dump_delta_chain_to_file(&obj->size,
1335 		    &obj->deltas, *f, repo);
1336 done:
1337 	if (err && *f) {
1338 		fclose(*f);
1339 		*f = NULL;
1340 	}
1341 	return err;
1342 }
1343 
1344 const struct got_error *
1345 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1346     struct got_object *obj, struct got_repository *repo)
1347 {
1348 	const struct got_error *err = NULL;
1349 
1350 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1351 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1352 
1353 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1354 		struct got_pack *pack;
1355 
1356 		pack = get_cached_pack(obj->path_packfile, repo);
1357 		if (pack == NULL) {
1358 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1359 			if (err)
1360 				goto done;
1361 		}
1362 
1363 		if (obj->pack_offset >= pack->filesize) {
1364 			err = got_error(GOT_ERR_PACK_OFFSET);
1365 			goto done;
1366 		}
1367 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1368 			err = got_error_from_errno();
1369 			goto done;
1370 		}
1371 
1372 		err = got_inflate_to_mem_fd(buf, len, pack->fd);
1373 	} else
1374 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, repo);
1375 done:
1376 	return err;
1377 }