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Date:: Thu Apr 26 17:47:10 2018 UTC
Message:: store fd instead of FILE in struct got_pack to prepare privsep
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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, 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, const char *path_packfile,
761     off_t delta_offset,size_t tslen, int delta_type, size_t delta_size,
762     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 (lseek(fd, base_offset, SEEK_SET) == -1)
793 		return got_error_from_errno();
794 
795 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
796 	    fd);
797 	if (err)
798 		return err;
799 
800 	return resolve_delta_chain(deltas, repo, fd, path_packfile,
801 	    base_offset, base_tslen, base_type, base_size, recursion - 1);
802 }
803 
804 static const struct got_error *
805 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
806     int fd, const char *path_packfile, off_t delta_offset,
807     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
808 {
809 	const struct got_error *err;
810 	struct got_object_id id;
811 	struct got_packidx_v2_hdr *packidx;
812 	int idx;
813 	off_t base_offset;
814 	uint8_t base_type;
815 	uint64_t base_size;
816 	size_t base_tslen;
817 	ssize_t n;
818 	char *path_base_packfile;
819 	struct got_pack *base_pack;
820 	off_t delta_data_offset;
821 	uint8_t *delta_buf;
822 	size_t delta_len;
823 
824 	n = read(fd, &id, sizeof(id));
825 	if (n < 0)
826 		return got_error_from_errno();
827 	if (n != sizeof(id))
828 		return got_error(GOT_ERR_BAD_PACKFILE);
829 
830 	delta_data_offset = lseek(fd, 0, SEEK_CUR);
831 	if (delta_data_offset == -1)
832 		return got_error_from_errno();
833 
834 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, fd);
835 	if (err)
836 		return err;
837 
838 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
839 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
840 	if (err)
841 		return err;
842 
843 	err = search_packidx(&packidx, &idx, repo, &id);
844 	if (err)
845 		return err;
846 
847 	base_offset = get_object_offset(packidx, idx);
848 	if (base_offset == (uint64_t)-1) {
849 		return got_error(GOT_ERR_BAD_PACKIDX);
850 	}
851 
852 	err = get_packfile_path(&path_base_packfile, repo, packidx);
853 	if (err)
854 		return err;
855 
856 	base_pack = get_cached_pack(path_base_packfile, repo);
857 	if (base_pack == NULL) {
858 		err = cache_pack(&base_pack, path_base_packfile, NULL, repo);
859 		if (err)
860 			goto done;
861 	}
862 
863 	if (lseek(base_pack->fd, base_offset, SEEK_SET) == -1) {
864 		err = got_error_from_errno();
865 		goto done;
866 	}
867 
868 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
869 	    base_pack->fd);
870 	if (err)
871 		goto done;
872 
873 	err = resolve_delta_chain(deltas, repo, base_pack->fd,
874 	    path_base_packfile, base_offset, base_tslen, base_type,
875 	    base_size, recursion - 1);
876 done:
877 	free(path_base_packfile);
878 	return err;
879 }
880 
881 static const struct got_error *
882 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
883     int fd, const char *path_packfile, off_t delta_offset, size_t tslen,
884     int delta_type, size_t delta_size, unsigned int recursion)
885 {
886 	const struct got_error *err = NULL;
887 
888 	if (--recursion == 0)
889 		return got_error(GOT_ERR_RECURSION);
890 
891 	switch (delta_type) {
892 	case GOT_OBJ_TYPE_COMMIT:
893 	case GOT_OBJ_TYPE_TREE:
894 	case GOT_OBJ_TYPE_BLOB:
895 	case GOT_OBJ_TYPE_TAG:
896 		/* Plain types are the final delta base. Recursion ends. */
897 		err = add_delta(deltas, path_packfile, delta_offset, tslen,
898 		    delta_type, delta_size, 0, NULL, 0);
899 		break;
900 	case GOT_OBJ_TYPE_OFFSET_DELTA:
901 		err = resolve_offset_delta(deltas, repo, fd, path_packfile,
902 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
903 		break;
904 	case GOT_OBJ_TYPE_REF_DELTA:
905 		err = resolve_ref_delta(deltas, repo, fd, path_packfile,
906 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
907 		break;
908 	default:
909 		return got_error(GOT_ERR_OBJ_TYPE);
910 	}
911 
912 	return err;
913 }
914 
915 static const struct got_error *
916 open_delta_object(struct got_object **obj, struct got_repository *repo,
917     struct got_packidx_v2_hdr *packidx, const char *path_packfile,
918     int fd, struct got_object_id *id, off_t offset, size_t tslen,
919     int delta_type, size_t delta_size)
920 {
921 	const struct got_error *err = NULL;
922 	int resolved_type;
923 
924 	*obj = calloc(1, sizeof(**obj));
925 	if (*obj == NULL)
926 		return got_error_from_errno();
927 
928 	(*obj)->flags = 0;
929 	(*obj)->hdrlen = 0;
930 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
931 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
932 	(*obj)->pack_offset = offset + tslen;
933 
934 	(*obj)->path_packfile = strdup(path_packfile);
935 	if ((*obj)->path_packfile == NULL) {
936 		err = got_error_from_errno();
937 		goto done;
938 	}
939 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
940 
941 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
942 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
943 
944 	err = resolve_delta_chain(&(*obj)->deltas, repo, fd,
945 	    path_packfile, offset, tslen, delta_type, delta_size,
946 	    GOT_DELTA_CHAIN_RECURSION_MAX);
947 	if (err)
948 		goto done;
949 
950 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
951 	if (err)
952 		goto done;
953 	(*obj)->type = resolved_type;
954 
955 done:
956 	if (err) {
957 		got_object_close(*obj);
958 		*obj = NULL;
959 	}
960 	return err;
961 }
962 
963 static const struct got_error *
964 open_packed_object(struct got_object **obj, struct got_repository *repo,
965     struct got_packidx_v2_hdr *packidx, int idx, struct got_object_id *id)
966 {
967 	const struct got_error *err = NULL;
968 	off_t offset;
969 	char *path_packfile;
970 	struct got_pack *pack;
971 	uint8_t type;
972 	uint64_t size;
973 	size_t tslen;
974 
975 	*obj = NULL;
976 
977 	offset = get_object_offset(packidx, idx);
978 	if (offset == (uint64_t)-1)
979 		return got_error(GOT_ERR_BAD_PACKIDX);
980 
981 	err = get_packfile_path(&path_packfile, repo, packidx);
982 	if (err)
983 		return err;
984 
985 	pack = get_cached_pack(path_packfile, repo);
986 	if (pack == NULL) {
987 		err = cache_pack(&pack, path_packfile, packidx, repo);
988 		if (err)
989 			goto done;
990 	}
991 
992 	if (lseek(pack->fd, offset, SEEK_SET) == -1) {
993 		err = got_error_from_errno();
994 		goto done;
995 	}
996 
997 	err = parse_object_type_and_size(&type, &size, &tslen, pack->fd);
998 	if (err)
999 		goto done;
1000 
1001 	switch (type) {
1002 	case GOT_OBJ_TYPE_COMMIT:
1003 	case GOT_OBJ_TYPE_TREE:
1004 	case GOT_OBJ_TYPE_BLOB:
1005 	case GOT_OBJ_TYPE_TAG:
1006 		err = open_plain_object(obj, path_packfile, id, type,
1007 		    offset + tslen, size);
1008 		break;
1009 
1010 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1011 	case GOT_OBJ_TYPE_REF_DELTA:
1012 		err = open_delta_object(obj, repo, packidx, path_packfile,
1013 		    pack->fd, id, offset, tslen, type, size);
1014 		break;
1015 
1016 	default:
1017 		err = got_error(GOT_ERR_OBJ_TYPE);
1018 		goto done;
1019 	}
1020 done:
1021 	free(path_packfile);
1022 	return err;
1023 }
1024 
1025 const struct got_error *
1026 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1027     struct got_repository *repo)
1028 {
1029 	const struct got_error *err = NULL;
1030 	struct got_packidx_v2_hdr *packidx = NULL;
1031 	int idx;
1032 
1033 	err = search_packidx(&packidx, &idx, repo, id);
1034 	if (err)
1035 		return err;
1036 
1037 	err = open_packed_object(obj, repo, packidx, idx, id);
1038 	if (err)
1039 		return err;
1040 
1041 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1042 	return err;
1043 }
1044 
1045 static const struct got_error *
1046 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1047 {
1048 	struct got_delta *delta;
1049 	uint64_t base_size = 0, result_size = 0;
1050 
1051 	*max_size = 0;
1052 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1053 		/* Plain object types are the delta base. */
1054 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1055 		    delta->type != GOT_OBJ_TYPE_TREE &&
1056 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1057 		    delta->type != GOT_OBJ_TYPE_TAG) {
1058 			const struct got_error *err;
1059 			err = got_delta_get_sizes(&base_size, &result_size,
1060 			    delta->delta_buf, delta->delta_len);
1061 			if (err)
1062 				return err;
1063 		} else
1064 			base_size = delta->size;
1065 		if (base_size > *max_size)
1066 			*max_size = base_size;
1067 		if (result_size > *max_size)
1068 			*max_size = result_size;
1069 	}
1070 
1071 	return NULL;
1072 }
1073 
1074 static const struct got_error *
1075 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1076     FILE *outfile, struct got_repository *repo)
1077 {
1078 	const struct got_error *err = NULL;
1079 	struct got_delta *delta;
1080 	FILE *base_file = NULL, *accum_file = NULL;
1081 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1082 	size_t accum_size = 0;
1083 	uint64_t max_size;
1084 	int n = 0;
1085 
1086 	*result_size = 0;
1087 
1088 	if (SIMPLEQ_EMPTY(&deltas->entries))
1089 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1090 
1091 	/* We process small enough files entirely in memory for speed. */
1092 	err = get_delta_chain_max_size(&max_size, deltas);
1093 	if (err)
1094 		return err;
1095 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1096 		accum_buf = malloc(max_size);
1097 		if (accum_buf == NULL)
1098 			return got_error_from_errno();
1099 	} else {
1100 		base_file = got_opentemp();
1101 		if (base_file == NULL)
1102 			return got_error_from_errno();
1103 
1104 		accum_file = got_opentemp();
1105 		if (accum_file == NULL) {
1106 			err = got_error_from_errno();
1107 			fclose(base_file);
1108 			return err;
1109 		}
1110 	}
1111 
1112 	/* Deltas are ordered in ascending order. */
1113 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1114 		if (n == 0) {
1115 			struct got_pack *pack;
1116 			size_t base_len;
1117 
1118 			/* Plain object types are the delta base. */
1119 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1120 			    delta->type != GOT_OBJ_TYPE_TREE &&
1121 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1122 			    delta->type != GOT_OBJ_TYPE_TAG) {
1123 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1124 				goto done;
1125 			}
1126 
1127 			pack = get_cached_pack(delta->path_packfile, repo);
1128 			if (pack == NULL) {
1129 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1130 				goto done;
1131 			}
1132 
1133 			if (lseek(pack->fd, delta->offset + delta->tslen,
1134 			    SEEK_SET) == -1) {
1135 				err = got_error_from_errno();
1136 				goto done;
1137 			}
1138 			if (base_file)
1139 				err = got_inflate_to_file_fd(&base_len,
1140 				    pack->fd, base_file);
1141 			else {
1142 				err = got_inflate_to_mem_fd(&base_buf, &base_len,
1143 				    pack->fd);
1144 				if (base_len < max_size) {
1145 					uint8_t *p;
1146 					p = reallocarray(base_buf, 1, max_size);
1147 					if (p == NULL) {
1148 						err = got_error_from_errno();
1149 						goto done;
1150 					}
1151 					base_buf = p;
1152 				}
1153 			}
1154 			if (err)
1155 				goto done;
1156 			n++;
1157 			if (base_file)
1158 				rewind(base_file);
1159 			continue;
1160 		}
1161 
1162 		if (base_buf) {
1163 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1164 			    delta->delta_len, accum_buf, &accum_size);
1165 			n++;
1166 		} else {
1167 			err = got_delta_apply(base_file, delta->delta_buf,
1168 			    delta->delta_len,
1169 			    /* Final delta application writes to output file. */
1170 			    ++n < deltas->nentries ? accum_file : outfile,
1171 			    &accum_size);
1172 		}
1173 		if (err)
1174 			goto done;
1175 
1176 		if (n < deltas->nentries) {
1177 			/* Accumulated delta becomes the new base. */
1178 			if (base_buf) {
1179 				uint8_t *tmp = accum_buf;
1180 				accum_buf = base_buf;
1181 				base_buf = tmp;
1182 			} else {
1183 				FILE *tmp = accum_file;
1184 				accum_file = base_file;
1185 				base_file = tmp;
1186 				rewind(base_file);
1187 				rewind(accum_file);
1188 			}
1189 		}
1190 	}
1191 
1192 done:
1193 	free(base_buf);
1194 	if (accum_buf) {
1195 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1196 		free(accum_buf);
1197 		if (len != accum_size)
1198 			return got_ferror(outfile, GOT_ERR_IO);
1199 	}
1200 	if (base_file)
1201 		fclose(base_file);
1202 	if (accum_file)
1203 		fclose(accum_file);
1204 	rewind(outfile);
1205 	if (err == NULL)
1206 		*result_size = accum_size;
1207 	return err;
1208 }
1209 
1210 static const struct got_error *
1211 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1212     struct got_delta_chain *deltas, struct got_repository *repo)
1213 {
1214 	const struct got_error *err = NULL;
1215 	struct got_delta *delta;
1216 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1217 	size_t accum_size;
1218 	uint64_t max_size;
1219 	int n = 0;
1220 
1221 	*outbuf = NULL;
1222 	*outlen = 0;
1223 
1224 	if (SIMPLEQ_EMPTY(&deltas->entries))
1225 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1226 
1227 	err = get_delta_chain_max_size(&max_size, deltas);
1228 	if (err)
1229 		return err;
1230 	accum_buf = malloc(max_size);
1231 	if (accum_buf == NULL)
1232 		return got_error_from_errno();
1233 
1234 	/* Deltas are ordered in ascending order. */
1235 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1236 		if (n == 0) {
1237 			struct got_pack *pack;
1238 			size_t base_len;
1239 
1240 			/* Plain object types are the delta base. */
1241 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1242 			    delta->type != GOT_OBJ_TYPE_TREE &&
1243 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1244 			    delta->type != GOT_OBJ_TYPE_TAG) {
1245 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1246 				goto done;
1247 			}
1248 
1249 			pack = get_cached_pack(delta->path_packfile, repo);
1250 			if (pack == NULL) {
1251 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1252 				goto done;
1253 			}
1254 
1255 			if (lseek(pack->fd, delta->offset + delta->tslen,
1256 			    SEEK_SET) == -1) {
1257 				err = got_error_from_errno();
1258 				goto done;
1259 			}
1260 			err = got_inflate_to_mem_fd(&base_buf, &base_len,
1261 			    pack->fd);
1262 			if (base_len < max_size) {
1263 				uint8_t *p;
1264 				p = reallocarray(base_buf, 1, max_size);
1265 				if (p == NULL) {
1266 					err = got_error_from_errno();
1267 					goto done;
1268 				}
1269 				base_buf = p;
1270 			}
1271 			if (err)
1272 				goto done;
1273 			n++;
1274 			continue;
1275 		}
1276 
1277 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1278 		    delta->delta_len, accum_buf, &accum_size);
1279 		n++;
1280 		if (err)
1281 			goto done;
1282 
1283 		if (n < deltas->nentries) {
1284 			/* Accumulated delta becomes the new base. */
1285 			uint8_t *tmp = accum_buf;
1286 			accum_buf = base_buf;
1287 			base_buf = tmp;
1288 		}
1289 	}
1290 
1291 done:
1292 	free(base_buf);
1293 	if (err) {
1294 		free(accum_buf);
1295 		*outbuf = NULL;
1296 		*outlen = 0;
1297 	} else {
1298 		*outbuf = accum_buf;
1299 		*outlen = accum_size;
1300 	}
1301 	return err;
1302 }
1303 
1304 const struct got_error *
1305 got_packfile_extract_object(FILE **f, struct got_object *obj,
1306     struct got_repository *repo)
1307 {
1308 	const struct got_error *err = NULL;
1309 
1310 	*f = NULL;
1311 
1312 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1313 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1314 
1315 	*f = got_opentemp();
1316 	if (*f == NULL) {
1317 		err = got_error_from_errno();
1318 		goto done;
1319 	}
1320 
1321 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1322 		struct got_pack *pack;
1323 
1324 		pack = get_cached_pack(obj->path_packfile, repo);
1325 		if (pack == NULL) {
1326 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1327 			if (err)
1328 				goto done;
1329 		}
1330 
1331 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1332 			err = got_error_from_errno();
1333 			goto done;
1334 		}
1335 
1336 		err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1337 	} else
1338 		err = dump_delta_chain_to_file(&obj->size,
1339 		    &obj->deltas, *f, repo);
1340 done:
1341 	if (err && *f) {
1342 		fclose(*f);
1343 		*f = NULL;
1344 	}
1345 	return err;
1346 }
1347 
1348 const struct got_error *
1349 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1350     struct got_object *obj, struct got_repository *repo)
1351 {
1352 	const struct got_error *err = NULL;
1353 
1354 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1355 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1356 
1357 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1358 		struct got_pack *pack;
1359 
1360 		pack = get_cached_pack(obj->path_packfile, repo);
1361 		if (pack == NULL) {
1362 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1363 			if (err)
1364 				goto done;
1365 		}
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 }