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