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Date:: Fri Apr 27 09:25:46 2018 UTC
Message:: offsets in pack files should not make us seek beyond EOF
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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 
21 #include <dirent.h>
22 #include <fcntl.h>
23 #include <errno.h>
24 #include <stdio.h>
25 #include <stdint.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <limits.h>
29 #include <sha1.h>
30 #include <endian.h>
31 #include <zlib.h>
32 
33 #include "got_error.h"
34 #include "got_object.h"
35 #include "got_repository.h"
36 
37 #include "got_lib_sha1.h"
38 #include "got_lib_pack.h"
39 #include "got_lib_path.h"
40 #include "got_lib_delta.h"
41 #include "got_lib_zbuf.h"
42 #include "got_lib_object.h"
43 #include "got_lib_repository.h"
44 
45 #ifndef nitems
46 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
47 #endif
48 
49 #define GOT_PACK_PREFIX		"pack-"
50 #define GOT_PACKFILE_SUFFIX	".pack"
51 #define GOT_PACKIDX_SUFFIX		".idx"
52 #define GOT_PACKFILE_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
53 				SHA1_DIGEST_STRING_LENGTH - 1 + \
54 				strlen(GOT_PACKFILE_SUFFIX))
55 #define GOT_PACKIDX_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
56 				SHA1_DIGEST_STRING_LENGTH - 1 + \
57 				strlen(GOT_PACKIDX_SUFFIX))
58 
59 #ifndef MIN
60 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
61 #endif
62 
63 static const struct got_error *
64 verify_fanout_table(uint32_t *fanout_table)
65 {
66 	int i;
67 
68 	for (i = 0; i < 0xff - 1; i++) {
69 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
70 			return got_error(GOT_ERR_BAD_PACKIDX);
71 	}
72 
73 	return NULL;
74 }
75 
76 static const struct got_error *
77 get_packfile_size(size_t *size, const char *path)
78 {
79 	struct stat sb;
80 	char *dot;
81 
82 	*size = 0;
83 
84 	dot = strrchr(path, '.');
85 	if (dot == NULL)
86 		return got_error(GOT_ERR_BAD_PATH);
87 
88 	/* Path must point to a pack index or to a pack file. */
89 	if (strcmp(dot, ".idx") == 0) {
90 		const struct got_error *err = NULL;
91 		char *path_pack;
92 		char base_path[PATH_MAX];
93 
94 		/* Convert pack index path to pack file path. */
95 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
96 			return got_error(GOT_ERR_NO_SPACE);
97 		dot = strrchr(base_path, '.');
98 		if (dot == NULL)
99 			return got_error(GOT_ERR_BAD_PATH);
100 		*dot = '\0';
101 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
102 			return got_error_from_errno();
103 
104 		if (stat(path_pack, &sb) != 0)
105 			err = got_error_from_errno();
106 		free(path_pack);
107 		if (err)
108 			return err;
109 	} else if (strcmp(dot, ".pack") == 0) {
110 		if (stat(path, &sb) != 0)
111 			return got_error_from_errno();
112 	} else
113 		return got_error(GOT_ERR_BAD_PATH);
114 
115 	*size = sb.st_size;
116 	return 0;
117 }
118 
119 const struct got_error *
120 got_packidx_open(struct got_packidx_v2_hdr **packidx, const char *path)
121 {
122 	struct got_packidx_v2_hdr *p;
123 	FILE *f;
124 	const struct got_error *err = NULL;
125 	size_t n, nobj, packfile_size;
126 	SHA1_CTX ctx;
127 	uint8_t sha1[SHA1_DIGEST_LENGTH];
128 
129 	SHA1Init(&ctx);
130 
131 	f = fopen(path, "rb");
132 	if (f == NULL)
133 		return got_error_from_errno();
134 
135 	err = get_packfile_size(&packfile_size, path);
136 	if (err)
137 		return err;
138 
139 	p = calloc(1, sizeof(*p));
140 	if (p == NULL) {
141 		err = got_error_from_errno();
142 		goto done;
143 	}
144 
145 	n = fread(&p->magic, sizeof(p->magic), 1, f);
146 	if (n != 1) {
147 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
148 		goto done;
149 	}
150 
151 	if (betoh32(p->magic) != GOT_PACKIDX_V2_MAGIC) {
152 		err = got_error(GOT_ERR_BAD_PACKIDX);
153 		goto done;
154 	}
155 
156 	SHA1Update(&ctx, (uint8_t *)&p->magic, sizeof(p->magic));
157 
158 	n = fread(&p->version, sizeof(p->version), 1, f);
159 	if (n != 1) {
160 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
161 		goto done;
162 	}
163 
164 	if (betoh32(p->version) != GOT_PACKIDX_VERSION) {
165 		err = got_error(GOT_ERR_BAD_PACKIDX);
166 		goto done;
167 	}
168 
169 	SHA1Update(&ctx, (uint8_t *)&p->version, sizeof(p->version));
170 
171 	n = fread(&p->fanout_table, sizeof(p->fanout_table), 1, f);
172 	if (n != 1) {
173 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
174 		goto done;
175 	}
176 
177 	err = verify_fanout_table(p->fanout_table);
178 	if (err)
179 		goto done;
180 
181 	SHA1Update(&ctx, (uint8_t *)p->fanout_table, sizeof(p->fanout_table));
182 
183 	nobj = betoh32(p->fanout_table[0xff]);
184 
185 	p->sorted_ids = calloc(nobj, sizeof(*p->sorted_ids));
186 	if (p->sorted_ids == NULL) {
187 		err = got_error_from_errno();
188 		goto done;
189 	}
190 
191 	n = fread(p->sorted_ids, sizeof(*p->sorted_ids), nobj, f);
192 	if (n != nobj) {
193 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
194 		goto done;
195 	}
196 
197 	SHA1Update(&ctx, (uint8_t *)p->sorted_ids,
198 	    nobj * sizeof(*p->sorted_ids));
199 
200 	p->crc32 = calloc(nobj, sizeof(*p->crc32));
201 	if (p->crc32 == NULL) {
202 		err = got_error_from_errno();
203 		goto done;
204 	}
205 
206 	n = fread(p->crc32, sizeof(*p->crc32), nobj, f);
207 	if (n != nobj) {
208 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
209 		goto done;
210 	}
211 
212 	SHA1Update(&ctx, (uint8_t *)p->crc32, nobj * sizeof(*p->crc32));
213 
214 	p->offsets = calloc(nobj, sizeof(*p->offsets));
215 	if (p->offsets == NULL) {
216 		err = got_error_from_errno();
217 		goto done;
218 	}
219 
220 	n = fread(p->offsets, sizeof(*p->offsets), nobj, f);
221 	if (n != nobj) {
222 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
223 		goto done;
224 	}
225 
226 	SHA1Update(&ctx, (uint8_t *)p->offsets, nobj * sizeof(*p->offsets));
227 
228 	/* Large file offsets are contained only in files > 2GB. */
229 	if (packfile_size <= 0x80000000)
230 		goto checksum;
231 
232 	p->large_offsets = calloc(nobj, sizeof(*p->large_offsets));
233 	if (p->large_offsets == NULL) {
234 		err = got_error_from_errno();
235 		goto done;
236 	}
237 
238 	n = fread(p->large_offsets, sizeof(*p->large_offsets), nobj, f);
239 	if (n != nobj) {
240 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
241 		goto done;
242 	}
243 
244 	SHA1Update(&ctx, (uint8_t*)p->large_offsets,
245 	    nobj * sizeof(*p->large_offsets));
246 
247 checksum:
248 	n = fread(&p->trailer, sizeof(p->trailer), 1, f);
249 	if (n != 1) {
250 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
251 		goto done;
252 	}
253 
254 	SHA1Update(&ctx, p->trailer.packfile_sha1, SHA1_DIGEST_LENGTH);
255 	SHA1Final(sha1, &ctx);
256 	if (memcmp(p->trailer.packidx_sha1, sha1, SHA1_DIGEST_LENGTH) != 0)
257 		err = got_error(GOT_ERR_PACKIDX_CSUM);
258 done:
259 	fclose(f);
260 	if (err)
261 		got_packidx_close(p);
262 	else
263 		*packidx = p;
264 	return err;
265 }
266 
267 void
268 got_packidx_close(struct got_packidx_v2_hdr *packidx)
269 {
270 	free(packidx->sorted_ids);
271 	free(packidx->offsets);
272 	free(packidx->crc32);
273 	free(packidx->large_offsets);
274 	free(packidx);
275 }
276 
277 static int
278 is_packidx_filename(const char *name, size_t len)
279 {
280 	if (len != GOT_PACKIDX_NAMELEN)
281 		return 0;
282 
283 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
284 		return 0;
285 
286 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
287 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
288 		return 0;
289 
290 	return 1;
291 }
292 
293 static off_t
294 get_object_offset(struct got_packidx_v2_hdr *packidx, int idx)
295 {
296 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
297 	uint32_t offset = betoh32(packidx->offsets[idx]);
298 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
299 		uint64_t loffset;
300 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
301 		if (idx < 0 || idx > totobj || packidx->large_offsets == NULL)
302 			return -1;
303 		loffset = betoh64(packidx->large_offsets[idx]);
304 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
305 	}
306 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
307 }
308 
309 static const struct got_error *
310 get_packfile_path(char **path_packfile, struct got_repository *repo,
311     struct got_packidx_v2_hdr *packidx);
312 
313 static int
314 get_object_idx(struct got_packidx_v2_hdr *packidx, struct got_object_id *id, struct got_repository *repo)
315 {
316 	u_int8_t id0 = id->sha1[0];
317 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
318 	int i = 0;
319 
320 	if (id0 > 0)
321 		i = betoh32(packidx->fanout_table[id0 - 1]);
322 
323 	while (i < totobj) {
324 		struct got_object_id *oid = &packidx->sorted_ids[i];
325 		int cmp = got_object_id_cmp(id, oid);
326 
327 		if (cmp == 0)
328 			return i;
329 		i++;
330 	}
331 
332 	return -1;
333 }
334 
335 static struct got_packidx_v2_hdr *
336 dup_packidx(struct got_packidx_v2_hdr *packidx)
337 {
338 	struct got_packidx_v2_hdr *p;
339 	size_t nobj;
340 
341 	p = calloc(1, sizeof(*p));
342 	if (p == NULL)
343 		return NULL;
344 
345 	memcpy(p, packidx, sizeof(*p));
346 	p->sorted_ids = NULL;
347 	p->crc32 = NULL;
348 	p->offsets = NULL;
349 	p->large_offsets = NULL;
350 
351 	nobj = betoh32(p->fanout_table[0xff]);
352 
353 	p->sorted_ids = calloc(nobj, sizeof(*p->sorted_ids));
354 	if (p->sorted_ids == NULL)
355 		goto err;
356 	memcpy(p->sorted_ids, packidx->sorted_ids,
357 	    nobj * sizeof(*p->sorted_ids));
358 
359 	p->crc32 = calloc(nobj, sizeof(*p->crc32));
360 	if (p->crc32 == NULL)
361 		goto err;
362 	memcpy(p->crc32, packidx->crc32, nobj * sizeof(*p->crc32));
363 
364 	p->offsets = calloc(nobj, sizeof(*p->offsets));
365 	if (p->offsets == NULL)
366 		goto err;
367 	memcpy(p->offsets, packidx->offsets, nobj * sizeof(*p->offsets));
368 
369 	if (p->large_offsets) {
370 		p->large_offsets = calloc(nobj, sizeof(*p->large_offsets));
371 		if (p->large_offsets == NULL)
372 			goto err;
373 		memcpy(p->large_offsets, packidx->large_offsets,
374 		    nobj * sizeof(*p->large_offsets));
375 	}
376 
377 	return p;
378 
379 err:
380 	free(p->large_offsets);
381 	free(p->offsets);
382 	free(p->crc32);
383 	free(p->sorted_ids);
384 	free(p);
385 	return NULL;
386 }
387 
388 static void
389 cache_packidx(struct got_packidx_v2_hdr *packidx, struct got_repository *repo)
390 {
391 	int i;
392 
393 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
394 		if (repo->packidx_cache[i] == NULL)
395 			break;
396 	}
397 
398 	if (i == nitems(repo->packidx_cache)) {
399 		got_packidx_close(repo->packidx_cache[i - 1]);
400 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
401 		    sizeof(repo->packidx_cache) -
402 		    sizeof(repo->packidx_cache[0]));
403 		i = 0;
404 	}
405 
406 	repo->packidx_cache[i] = dup_packidx(packidx);
407 }
408 
409 static const struct got_error *
410 search_packidx(struct got_packidx_v2_hdr **packidx, int *idx,
411     struct got_repository *repo, struct got_object_id *id)
412 {
413 	const struct got_error *err;
414 	char *path_packdir;
415 	DIR *packdir;
416 	struct dirent *dent;
417 	char *path_packidx;
418 	int i;
419 
420 	/* Search pack index cache. */
421 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
422 		if (repo->packidx_cache[i] == NULL)
423 			break;
424 		*idx = get_object_idx(repo->packidx_cache[i], id, repo);
425 		if (*idx != -1) {
426 			*packidx = repo->packidx_cache[i];
427 			return NULL;
428 		}
429 	}
430 	/* No luck. Search the filesystem. */
431 
432 	path_packdir = got_repo_get_path_objects_pack(repo);
433 	if (path_packdir == NULL)
434 		return got_error_from_errno();
435 
436 	packdir = opendir(path_packdir);
437 	if (packdir == NULL) {
438 		err = got_error_from_errno();
439 		goto done;
440 	}
441 
442 	while ((dent = readdir(packdir)) != NULL) {
443 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
444 			continue;
445 
446 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
447 		    dent->d_name) == -1) {
448 			err = got_error_from_errno();
449 			goto done;
450 		}
451 
452 		err = got_packidx_open(packidx, path_packidx);
453 		free(path_packidx);
454 		if (err)
455 			goto done;
456 
457 		*idx = get_object_idx(*packidx, id, repo);
458 		if (*idx != -1) {
459 			err = NULL; /* found the object */
460 			cache_packidx(*packidx, repo);
461 			goto done;
462 		}
463 
464 		got_packidx_close(*packidx);
465 		*packidx = NULL;
466 	}
467 
468 	err = got_error(GOT_ERR_NO_OBJ);
469 done:
470 	free(path_packdir);
471 	if (packdir && closedir(packdir) != 0 && err == 0)
472 		err = got_error_from_errno();
473 	return err;
474 }
475 
476 static const struct got_error *
477 get_packfile_path(char **path_packfile, struct got_repository *repo,
478     struct got_packidx_v2_hdr *packidx)
479 {
480 	char *path_packdir;
481 	char hex[SHA1_DIGEST_STRING_LENGTH];
482 	char *sha1str;
483 
484 	path_packdir = got_repo_get_path_objects_pack(repo);
485 	if (path_packdir == NULL)
486 		return got_error_from_errno();
487 
488 	sha1str = got_sha1_digest_to_str(packidx->trailer.packfile_sha1,
489 	    hex, sizeof(hex));
490 	if (sha1str == NULL)
491 		return got_error(GOT_ERR_PACKIDX_CSUM);
492 
493 	if (asprintf(path_packfile, "%s/%s%s%s", path_packdir,
494 	    GOT_PACK_PREFIX, sha1str, GOT_PACKFILE_SUFFIX) == -1) {
495 		*path_packfile = NULL;
496 		return got_error_from_errno();
497 	}
498 
499 	return NULL;
500 }
501 
502 const struct got_error *
503 read_packfile_hdr(int fd, struct got_packidx_v2_hdr *packidx)
504 {
505 	const struct got_error *err = NULL;
506 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
507 	struct got_packfile_hdr hdr;
508 	ssize_t n;
509 
510 	n = read(fd, &hdr, sizeof(hdr));
511 	if (n < 0)
512 		return got_error_from_errno();
513 	if (n != sizeof(hdr))
514 		return got_error(GOT_ERR_BAD_PACKFILE);
515 
516 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
517 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
518 	    betoh32(hdr.nobjects) != totobj)
519 		err = got_error(GOT_ERR_BAD_PACKFILE);
520 
521 	return err;
522 }
523 
524 static const struct got_error *
525 open_packfile(int *fd, const char *path_packfile,
526     struct got_repository *repo, struct got_packidx_v2_hdr *packidx)
527 {
528 	const struct got_error *err = NULL;
529 
530 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
531 	if (*fd == -1)
532 		return got_error_from_errno();
533 
534 	if (packidx) {
535 		err = read_packfile_hdr(*fd, packidx);
536 		if (err) {
537 			close(*fd);
538 			*fd = -1;
539 		}
540 	}
541 	return err;
542 }
543 
544 void
545 got_pack_close(struct got_pack *pack)
546 {
547 	close(pack->fd);
548 	pack->fd = -1;
549 	free(pack->path_packfile);
550 	pack->path_packfile = NULL;
551 	pack->filesize = 0;
552 }
553 
554 static const struct got_error *
555 cache_pack(struct got_pack **packp, const char *path_packfile,
556     struct got_packidx_v2_hdr *packidx, struct got_repository *repo)
557 {
558 	const struct got_error *err = NULL;
559 	struct got_pack *pack = NULL;
560 	int i;
561 
562 	if (packp)
563 		*packp = NULL;
564 
565 	for (i = 0; i < nitems(repo->packs); i++) {
566 		pack = &repo->packs[i];
567 		if (pack->path_packfile == NULL)
568 			break;
569 		if (strcmp(pack->path_packfile, path_packfile) == 0)
570 			return NULL;
571 	}
572 
573 	if (i == nitems(repo->packs) - 1) {
574 		got_pack_close(&repo->packs[i - 1]);
575 		memmove(&repo->packs[1], &repo->packs[0],
576 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
577 		i = 0;
578 	}
579 
580 	pack = &repo->packs[i];
581 
582 	pack->path_packfile = strdup(path_packfile);
583 	if (pack->path_packfile == NULL) {
584 		err = got_error_from_errno();
585 		goto done;
586 	}
587 
588 	err = open_packfile(&pack->fd, path_packfile, repo, packidx);
589 	if (err)
590 		goto done;
591 
592 	err = get_packfile_size(&pack->filesize, path_packfile);
593 done:
594 	if (err) {
595 		if (pack)
596 			free(pack->path_packfile);
597 		free(pack);
598 	} else if (packp)
599 		*packp = pack;
600 	return err;
601 }
602 
603 struct got_pack *
604 get_cached_pack(const char *path_packfile, struct got_repository *repo)
605 {
606 	struct got_pack *pack = NULL;
607 	int i;
608 
609 	for (i = 0; i < nitems(repo->packs); i++) {
610 		pack = &repo->packs[i];
611 		if (pack->path_packfile == NULL)
612 			break;
613 		if (strcmp(pack->path_packfile, path_packfile) == 0)
614 			return pack;
615 	}
616 
617 	return NULL;
618 }
619 
620 static const struct got_error *
621 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len, int fd)
622 {
623 	uint8_t t = 0;
624 	uint64_t s = 0;
625 	uint8_t sizeN;
626 	ssize_t n;
627 	int i = 0;
628 
629 	do {
630 		/* We do not support size values which don't fit in 64 bit. */
631 		if (i > 9)
632 			return got_error(GOT_ERR_NO_SPACE);
633 
634 		n = read(fd, &sizeN, sizeof(sizeN));
635 		if (n < 0)
636 			return got_error_from_errno();
637 		if (n != sizeof(sizeN))
638 			return got_error(GOT_ERR_BAD_PACKFILE);
639 
640 		if (i == 0) {
641 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
642 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
643 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
644 		} else {
645 			size_t shift = 4 + 7 * (i - 1);
646 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
647 		}
648 		i++;
649 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
650 
651 	*type = t;
652 	*size = s;
653 	*len = i * sizeof(sizeN);
654 	return NULL;
655 }
656 
657 static const struct got_error *
658 open_plain_object(struct got_object **obj, const char *path_packfile,
659     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
660 {
661 	*obj = calloc(1, sizeof(**obj));
662 	if (*obj == NULL)
663 		return got_error_from_errno();
664 
665 	(*obj)->path_packfile = strdup(path_packfile);
666 	if ((*obj)->path_packfile == NULL) {
667 		const struct got_error *err = got_error_from_errno();
668 		free(*obj);
669 		*obj = NULL;
670 		return err;
671 	}
672 
673 	(*obj)->type = type;
674 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
675 	(*obj)->hdrlen = 0;
676 	(*obj)->size = size;
677 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
678 	(*obj)->pack_offset = offset;
679 
680 	return NULL;
681 }
682 
683 static const struct got_error *
684 parse_negative_offset(int64_t *offset, size_t *len, int fd)
685 {
686 	int64_t o = 0;
687 	uint8_t offN;
688 	ssize_t n;
689 	int i = 0;
690 
691 	do {
692 		/* We do not support offset values which don't fit in 64 bit. */
693 		if (i > 8)
694 			return got_error(GOT_ERR_NO_SPACE);
695 
696 		n = read(fd, &offN, sizeof(offN));
697 		if (n < 0)
698 			return got_error_from_errno();
699 		if (n != sizeof(offN))
700 			return got_error(GOT_ERR_BAD_PACKFILE);
701 
702 		if (i == 0)
703 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
704 		else {
705 			o++;
706 			o <<= 7;
707 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
708 		}
709 		i++;
710 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
711 
712 	*offset = o;
713 	*len = i * sizeof(offN);
714 	return NULL;
715 }
716 
717 static const struct got_error *
718 parse_offset_delta(off_t *base_offset, int fd, off_t offset)
719 {
720 	const struct got_error *err;
721 	int64_t negoffset;
722 	size_t negofflen;
723 
724 	err = parse_negative_offset(&negoffset, &negofflen, fd);
725 	if (err)
726 		return err;
727 
728 	/* Compute the base object's offset (must be in the same pack file). */
729 	*base_offset = (offset - negoffset);
730 	if (*base_offset <= 0)
731 		return got_error(GOT_ERR_BAD_PACKFILE);
732 
733 	return NULL;
734 }
735 
736 static const struct got_error *
737 resolve_delta_chain(struct got_delta_chain *, struct got_repository *,
738     int, size_t, const char *, off_t, size_t, int, size_t, unsigned int);
739 
740 static const struct got_error *
741 add_delta(struct got_delta_chain *deltas, const char *path_packfile,
742     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
743     size_t delta_data_offset, uint8_t *delta_buf, size_t delta_len)
744 {
745 	struct got_delta *delta;
746 
747 	delta = got_delta_open(path_packfile, delta_offset, tslen,
748 	    delta_type, delta_size, delta_data_offset, delta_buf,
749 	    delta_len);
750 	if (delta == NULL)
751 		return got_error_from_errno();
752 	/* delta is freed in got_object_close() */
753 	deltas->nentries++;
754 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
755 	return NULL;
756 }
757 
758 static const struct got_error *
759 resolve_offset_delta(struct got_delta_chain *deltas,
760     struct got_repository *repo, int fd, size_t packfile_size,
761     const char *path_packfile, off_t delta_offset, size_t tslen,
762     int delta_type, size_t delta_size, unsigned int recursion)
763 
764 {
765 	const struct got_error *err;
766 	off_t base_offset;
767 	uint8_t base_type;
768 	uint64_t base_size;
769 	size_t base_tslen;
770 	off_t delta_data_offset;
771 	uint8_t *delta_buf;
772 	size_t delta_len;
773 
774 	err = parse_offset_delta(&base_offset, fd, delta_offset);
775 	if (err)
776 		return err;
777 
778 	delta_data_offset = lseek(fd, 0, SEEK_CUR);
779 	if (delta_data_offset == -1)
780 		return got_error_from_errno();
781 
782 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, fd);
783 	if (err)
784 		return err;
785 
786 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
787 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
788 	if (err)
789 		return err;
790 
791 	/* An offset delta must be in the same packfile. */
792 	if (base_offset >= packfile_size)
793 		return got_error(GOT_ERR_PACK_OFFSET);
794 	if (lseek(fd, base_offset, SEEK_SET) == -1)
795 		return got_error_from_errno();
796 
797 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
798 	    fd);
799 	if (err)
800 		return err;
801 
802 	return resolve_delta_chain(deltas, repo, fd, packfile_size,
803 	    path_packfile, base_offset, base_tslen, base_type, base_size,
804 	    recursion - 1);
805 }
806 
807 static const struct got_error *
808 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
809     int fd, const char *path_packfile, off_t delta_offset,
810     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
811 {
812 	const struct got_error *err;
813 	struct got_object_id id;
814 	struct got_packidx_v2_hdr *packidx;
815 	int idx;
816 	off_t base_offset;
817 	uint8_t base_type;
818 	uint64_t base_size;
819 	size_t base_tslen;
820 	ssize_t n;
821 	char *path_base_packfile;
822 	struct got_pack *base_pack;
823 	off_t delta_data_offset;
824 	uint8_t *delta_buf;
825 	size_t delta_len;
826 
827 	n = read(fd, &id, sizeof(id));
828 	if (n < 0)
829 		return got_error_from_errno();
830 	if (n != sizeof(id))
831 		return got_error(GOT_ERR_BAD_PACKFILE);
832 
833 	delta_data_offset = lseek(fd, 0, SEEK_CUR);
834 	if (delta_data_offset == -1)
835 		return got_error_from_errno();
836 
837 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, fd);
838 	if (err)
839 		return err;
840 
841 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
842 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
843 	if (err)
844 		return err;
845 
846 	err = search_packidx(&packidx, &idx, repo, &id);
847 	if (err)
848 		return err;
849 
850 	base_offset = get_object_offset(packidx, idx);
851 	if (base_offset == (uint64_t)-1) {
852 		return got_error(GOT_ERR_BAD_PACKIDX);
853 	}
854 
855 	err = get_packfile_path(&path_base_packfile, repo, packidx);
856 	if (err)
857 		return err;
858 
859 	base_pack = get_cached_pack(path_base_packfile, repo);
860 	if (base_pack == NULL) {
861 		err = cache_pack(&base_pack, path_base_packfile, NULL, repo);
862 		if (err)
863 			goto done;
864 	}
865 
866 	if (base_offset >= base_pack->filesize) {
867 		err = got_error(GOT_ERR_PACK_OFFSET);
868 		goto done;
869 	}
870 	if (lseek(base_pack->fd, base_offset, SEEK_SET) == -1) {
871 		err = got_error_from_errno();
872 		goto done;
873 	}
874 
875 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
876 	    base_pack->fd);
877 	if (err)
878 		goto done;
879 
880 	err = resolve_delta_chain(deltas, repo, base_pack->fd,
881 	    base_pack->filesize, path_base_packfile, base_offset,
882 	    base_tslen, base_type, base_size, recursion - 1);
883 done:
884 	free(path_base_packfile);
885 	return err;
886 }
887 
888 static const struct got_error *
889 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
890     int fd, size_t packfile_size, const char *path_packfile, off_t delta_offset,
891     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
892 {
893 	const struct got_error *err = NULL;
894 
895 	if (--recursion == 0)
896 		return got_error(GOT_ERR_RECURSION);
897 
898 	switch (delta_type) {
899 	case GOT_OBJ_TYPE_COMMIT:
900 	case GOT_OBJ_TYPE_TREE:
901 	case GOT_OBJ_TYPE_BLOB:
902 	case GOT_OBJ_TYPE_TAG:
903 		/* Plain types are the final delta base. Recursion ends. */
904 		err = add_delta(deltas, path_packfile, delta_offset, tslen,
905 		    delta_type, delta_size, 0, NULL, 0);
906 		break;
907 	case GOT_OBJ_TYPE_OFFSET_DELTA:
908 		err = resolve_offset_delta(deltas, repo, fd, packfile_size,
909 		    path_packfile, delta_offset, tslen, delta_type, delta_size,
910 		    recursion - 1);
911 		break;
912 	case GOT_OBJ_TYPE_REF_DELTA:
913 		err = resolve_ref_delta(deltas, repo, fd, path_packfile,
914 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
915 		break;
916 	default:
917 		return got_error(GOT_ERR_OBJ_TYPE);
918 	}
919 
920 	return err;
921 }
922 
923 static const struct got_error *
924 open_delta_object(struct got_object **obj, struct got_repository *repo,
925     struct got_packidx_v2_hdr *packidx, const char *path_packfile,
926     int fd, size_t packfile_size, struct got_object_id *id, off_t offset,
927     size_t tslen, int delta_type, size_t delta_size)
928 {
929 	const struct got_error *err = NULL;
930 	int resolved_type;
931 
932 	*obj = calloc(1, sizeof(**obj));
933 	if (*obj == NULL)
934 		return got_error_from_errno();
935 
936 	(*obj)->flags = 0;
937 	(*obj)->hdrlen = 0;
938 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
939 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
940 	(*obj)->pack_offset = offset + tslen;
941 
942 	(*obj)->path_packfile = strdup(path_packfile);
943 	if ((*obj)->path_packfile == NULL) {
944 		err = got_error_from_errno();
945 		goto done;
946 	}
947 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
948 
949 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
950 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
951 
952 	err = resolve_delta_chain(&(*obj)->deltas, repo, fd, packfile_size,
953 	    path_packfile, offset, tslen, delta_type, delta_size,
954 	    GOT_DELTA_CHAIN_RECURSION_MAX);
955 	if (err)
956 		goto done;
957 
958 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
959 	if (err)
960 		goto done;
961 	(*obj)->type = resolved_type;
962 
963 done:
964 	if (err) {
965 		got_object_close(*obj);
966 		*obj = NULL;
967 	}
968 	return err;
969 }
970 
971 static const struct got_error *
972 open_packed_object(struct got_object **obj, struct got_repository *repo,
973     struct got_packidx_v2_hdr *packidx, int idx, struct got_object_id *id)
974 {
975 	const struct got_error *err = NULL;
976 	off_t offset;
977 	char *path_packfile;
978 	struct got_pack *pack;
979 	uint8_t type;
980 	uint64_t size;
981 	size_t tslen;
982 
983 	*obj = NULL;
984 
985 	offset = get_object_offset(packidx, idx);
986 	if (offset == (uint64_t)-1)
987 		return got_error(GOT_ERR_BAD_PACKIDX);
988 
989 	err = get_packfile_path(&path_packfile, repo, packidx);
990 	if (err)
991 		return err;
992 
993 	pack = get_cached_pack(path_packfile, repo);
994 	if (pack == NULL) {
995 		err = cache_pack(&pack, path_packfile, packidx, repo);
996 		if (err)
997 			goto done;
998 	}
999 
1000 	if (offset >= pack->filesize) {
1001 		err = got_error(GOT_ERR_PACK_OFFSET);
1002 		goto done;
1003 	}
1004 	if (lseek(pack->fd, offset, SEEK_SET) == -1) {
1005 		err = got_error_from_errno();
1006 		goto done;
1007 	}
1008 
1009 	err = parse_object_type_and_size(&type, &size, &tslen, pack->fd);
1010 	if (err)
1011 		goto done;
1012 
1013 	switch (type) {
1014 	case GOT_OBJ_TYPE_COMMIT:
1015 	case GOT_OBJ_TYPE_TREE:
1016 	case GOT_OBJ_TYPE_BLOB:
1017 	case GOT_OBJ_TYPE_TAG:
1018 		err = open_plain_object(obj, path_packfile, id, type,
1019 		    offset + tslen, size);
1020 		break;
1021 
1022 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1023 	case GOT_OBJ_TYPE_REF_DELTA:
1024 		err = open_delta_object(obj, repo, packidx, path_packfile,
1025 		    pack->fd, pack->filesize, id, offset, tslen, type, size);
1026 		break;
1027 
1028 	default:
1029 		err = got_error(GOT_ERR_OBJ_TYPE);
1030 		goto done;
1031 	}
1032 done:
1033 	free(path_packfile);
1034 	return err;
1035 }
1036 
1037 const struct got_error *
1038 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1039     struct got_repository *repo)
1040 {
1041 	const struct got_error *err = NULL;
1042 	struct got_packidx_v2_hdr *packidx = NULL;
1043 	int idx;
1044 
1045 	err = search_packidx(&packidx, &idx, repo, id);
1046 	if (err)
1047 		return err;
1048 
1049 	err = open_packed_object(obj, repo, packidx, idx, id);
1050 	if (err)
1051 		return err;
1052 
1053 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1054 	return err;
1055 }
1056 
1057 static const struct got_error *
1058 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1059 {
1060 	struct got_delta *delta;
1061 	uint64_t base_size = 0, result_size = 0;
1062 
1063 	*max_size = 0;
1064 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1065 		/* Plain object types are the delta base. */
1066 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1067 		    delta->type != GOT_OBJ_TYPE_TREE &&
1068 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1069 		    delta->type != GOT_OBJ_TYPE_TAG) {
1070 			const struct got_error *err;
1071 			err = got_delta_get_sizes(&base_size, &result_size,
1072 			    delta->delta_buf, delta->delta_len);
1073 			if (err)
1074 				return err;
1075 		} else
1076 			base_size = delta->size;
1077 		if (base_size > *max_size)
1078 			*max_size = base_size;
1079 		if (result_size > *max_size)
1080 			*max_size = result_size;
1081 	}
1082 
1083 	return NULL;
1084 }
1085 
1086 static const struct got_error *
1087 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1088     FILE *outfile, struct got_repository *repo)
1089 {
1090 	const struct got_error *err = NULL;
1091 	struct got_delta *delta;
1092 	FILE *base_file = NULL, *accum_file = NULL;
1093 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1094 	size_t accum_size = 0;
1095 	uint64_t max_size;
1096 	int n = 0;
1097 
1098 	*result_size = 0;
1099 
1100 	if (SIMPLEQ_EMPTY(&deltas->entries))
1101 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1102 
1103 	/* We process small enough files entirely in memory for speed. */
1104 	err = get_delta_chain_max_size(&max_size, deltas);
1105 	if (err)
1106 		return err;
1107 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1108 		accum_buf = malloc(max_size);
1109 		if (accum_buf == NULL)
1110 			return got_error_from_errno();
1111 	} else {
1112 		base_file = got_opentemp();
1113 		if (base_file == NULL)
1114 			return got_error_from_errno();
1115 
1116 		accum_file = got_opentemp();
1117 		if (accum_file == NULL) {
1118 			err = got_error_from_errno();
1119 			fclose(base_file);
1120 			return err;
1121 		}
1122 	}
1123 
1124 	/* Deltas are ordered in ascending order. */
1125 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1126 		if (n == 0) {
1127 			struct got_pack *pack;
1128 			size_t base_len;
1129 			off_t delta_data_offset;
1130 
1131 			/* Plain object types are the delta base. */
1132 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1133 			    delta->type != GOT_OBJ_TYPE_TREE &&
1134 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1135 			    delta->type != GOT_OBJ_TYPE_TAG) {
1136 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1137 				goto done;
1138 			}
1139 
1140 			pack = get_cached_pack(delta->path_packfile, repo);
1141 			if (pack == NULL) {
1142 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1143 				goto done;
1144 			}
1145 
1146 			delta_data_offset = delta->offset + delta->tslen;
1147 			if (delta_data_offset >= pack->filesize) {
1148 				err = got_error(GOT_ERR_PACK_OFFSET);
1149 				goto done;
1150 			}
1151 			if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1152 				err = got_error_from_errno();
1153 				goto done;
1154 			}
1155 			if (base_file)
1156 				err = got_inflate_to_file_fd(&base_len,
1157 				    pack->fd, base_file);
1158 			else {
1159 				err = got_inflate_to_mem_fd(&base_buf, &base_len,
1160 				    pack->fd);
1161 				if (base_len < max_size) {
1162 					uint8_t *p;
1163 					p = reallocarray(base_buf, 1, max_size);
1164 					if (p == NULL) {
1165 						err = got_error_from_errno();
1166 						goto done;
1167 					}
1168 					base_buf = p;
1169 				}
1170 			}
1171 			if (err)
1172 				goto done;
1173 			n++;
1174 			if (base_file)
1175 				rewind(base_file);
1176 			continue;
1177 		}
1178 
1179 		if (base_buf) {
1180 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1181 			    delta->delta_len, accum_buf, &accum_size);
1182 			n++;
1183 		} else {
1184 			err = got_delta_apply(base_file, delta->delta_buf,
1185 			    delta->delta_len,
1186 			    /* Final delta application writes to output file. */
1187 			    ++n < deltas->nentries ? accum_file : outfile,
1188 			    &accum_size);
1189 		}
1190 		if (err)
1191 			goto done;
1192 
1193 		if (n < deltas->nentries) {
1194 			/* Accumulated delta becomes the new base. */
1195 			if (base_buf) {
1196 				uint8_t *tmp = accum_buf;
1197 				accum_buf = base_buf;
1198 				base_buf = tmp;
1199 			} else {
1200 				FILE *tmp = accum_file;
1201 				accum_file = base_file;
1202 				base_file = tmp;
1203 				rewind(base_file);
1204 				rewind(accum_file);
1205 			}
1206 		}
1207 	}
1208 
1209 done:
1210 	free(base_buf);
1211 	if (accum_buf) {
1212 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1213 		free(accum_buf);
1214 		if (len != accum_size)
1215 			return got_ferror(outfile, GOT_ERR_IO);
1216 	}
1217 	if (base_file)
1218 		fclose(base_file);
1219 	if (accum_file)
1220 		fclose(accum_file);
1221 	rewind(outfile);
1222 	if (err == NULL)
1223 		*result_size = accum_size;
1224 	return err;
1225 }
1226 
1227 static const struct got_error *
1228 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1229     struct got_delta_chain *deltas, struct got_repository *repo)
1230 {
1231 	const struct got_error *err = NULL;
1232 	struct got_delta *delta;
1233 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1234 	size_t accum_size;
1235 	uint64_t max_size;
1236 	int n = 0;
1237 
1238 	*outbuf = NULL;
1239 	*outlen = 0;
1240 
1241 	if (SIMPLEQ_EMPTY(&deltas->entries))
1242 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1243 
1244 	err = get_delta_chain_max_size(&max_size, deltas);
1245 	if (err)
1246 		return err;
1247 	accum_buf = malloc(max_size);
1248 	if (accum_buf == NULL)
1249 		return got_error_from_errno();
1250 
1251 	/* Deltas are ordered in ascending order. */
1252 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1253 		if (n == 0) {
1254 			struct got_pack *pack;
1255 			size_t base_len;
1256 			size_t delta_data_offset;
1257 
1258 			/* Plain object types are the delta base. */
1259 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1260 			    delta->type != GOT_OBJ_TYPE_TREE &&
1261 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1262 			    delta->type != GOT_OBJ_TYPE_TAG) {
1263 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1264 				goto done;
1265 			}
1266 
1267 			pack = get_cached_pack(delta->path_packfile, repo);
1268 			if (pack == NULL) {
1269 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1270 				goto done;
1271 			}
1272 
1273 			delta_data_offset = delta->offset + delta->tslen;
1274 			if (delta_data_offset >= pack->filesize) {
1275 				err = got_error(GOT_ERR_PACK_OFFSET);
1276 				goto done;
1277 			}
1278 			if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1279 				err = got_error_from_errno();
1280 				goto done;
1281 			}
1282 			err = got_inflate_to_mem_fd(&base_buf, &base_len,
1283 			    pack->fd);
1284 			if (base_len < max_size) {
1285 				uint8_t *p;
1286 				p = reallocarray(base_buf, 1, max_size);
1287 				if (p == NULL) {
1288 					err = got_error_from_errno();
1289 					goto done;
1290 				}
1291 				base_buf = p;
1292 			}
1293 			if (err)
1294 				goto done;
1295 			n++;
1296 			continue;
1297 		}
1298 
1299 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1300 		    delta->delta_len, accum_buf, &accum_size);
1301 		n++;
1302 		if (err)
1303 			goto done;
1304 
1305 		if (n < deltas->nentries) {
1306 			/* Accumulated delta becomes the new base. */
1307 			uint8_t *tmp = accum_buf;
1308 			accum_buf = base_buf;
1309 			base_buf = tmp;
1310 		}
1311 	}
1312 
1313 done:
1314 	free(base_buf);
1315 	if (err) {
1316 		free(accum_buf);
1317 		*outbuf = NULL;
1318 		*outlen = 0;
1319 	} else {
1320 		*outbuf = accum_buf;
1321 		*outlen = accum_size;
1322 	}
1323 	return err;
1324 }
1325 
1326 const struct got_error *
1327 got_packfile_extract_object(FILE **f, struct got_object *obj,
1328     struct got_repository *repo)
1329 {
1330 	const struct got_error *err = NULL;
1331 
1332 	*f = NULL;
1333 
1334 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1335 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1336 
1337 	*f = got_opentemp();
1338 	if (*f == NULL) {
1339 		err = got_error_from_errno();
1340 		goto done;
1341 	}
1342 
1343 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1344 		struct got_pack *pack;
1345 
1346 		pack = get_cached_pack(obj->path_packfile, repo);
1347 		if (pack == NULL) {
1348 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1349 			if (err)
1350 				goto done;
1351 		}
1352 
1353 		if (obj->pack_offset >= pack->filesize) {
1354 			err = got_error(GOT_ERR_PACK_OFFSET);
1355 			goto done;
1356 		}
1357 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1358 			err = got_error_from_errno();
1359 			goto done;
1360 		}
1361 
1362 		err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1363 	} else
1364 		err = dump_delta_chain_to_file(&obj->size,
1365 		    &obj->deltas, *f, repo);
1366 done:
1367 	if (err && *f) {
1368 		fclose(*f);
1369 		*f = NULL;
1370 	}
1371 	return err;
1372 }
1373 
1374 const struct got_error *
1375 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1376     struct got_object *obj, struct got_repository *repo)
1377 {
1378 	const struct got_error *err = NULL;
1379 
1380 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1381 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1382 
1383 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1384 		struct got_pack *pack;
1385 
1386 		pack = get_cached_pack(obj->path_packfile, repo);
1387 		if (pack == NULL) {
1388 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1389 			if (err)
1390 				goto done;
1391 		}
1392 
1393 		if (obj->pack_offset >= pack->filesize) {
1394 			err = got_error(GOT_ERR_PACK_OFFSET);
1395 			goto done;
1396 		}
1397 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1398 			err = got_error_from_errno();
1399 			goto done;
1400 		}
1401 
1402 		err = got_inflate_to_mem_fd(buf, len, pack->fd);
1403 	} else
1404 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, repo);
1405 done:
1406 	return err;
1407 }