1 /*
2  * Copyright (c) 2018, 2019 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 #include <sys/uio.h>
21 #include <sys/mman.h>
22 
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <zlib.h>
33 #include <imsg.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_opentemp.h"
38 #include "got_path.h"
39 
40 #include "got_lib_sha1.h"
41 #include "got_lib_delta.h"
42 #include "got_lib_inflate.h"
43 #include "got_lib_object.h"
44 #include "got_lib_object_parse.h"
45 #include "got_lib_privsep.h"
46 #include "got_lib_pack.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #ifndef MIN
53 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
54 #endif
55 
56 static const struct got_error *
57 verify_fanout_table(uint32_t *fanout_table)
58 {
59 	int i;
60 
61 	for (i = 0; i < 0xff - 1; i++) {
62 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
63 			return got_error(GOT_ERR_BAD_PACKIDX);
64 	}
65 
66 	return NULL;
67 }
68 
69 const struct got_error *
70 got_packidx_init_hdr(struct got_packidx *p, int verify)
71 {
72 	const struct got_error *err = NULL;
73 	struct got_packidx_v2_hdr *h;
74 	SHA1_CTX ctx;
75 	uint8_t sha1[SHA1_DIGEST_LENGTH];
76 	size_t nobj, len_fanout, len_ids, offset, remain;
77 	ssize_t n;
78 
79 	SHA1Init(&ctx);
80 
81 	h = &p->hdr;
82 	offset = 0;
83 	remain = p->len;
84 
85 	if (remain < sizeof(*h->magic)) {
86 		err = got_error(GOT_ERR_BAD_PACKIDX);
87 		goto done;
88 	}
89 	if (p->map)
90 		h->magic = (uint32_t *)(p->map + offset);
91 	else {
92 		h->magic = malloc(sizeof(*h->magic));
93 		if (h->magic == NULL) {
94 			err = got_error_from_errno("malloc");
95 			goto done;
96 		}
97 		n = read(p->fd, h->magic, sizeof(*h->magic));
98 		if (n < 0)
99 			err = got_error_from_errno("read");
100 		else if (n != sizeof(*h->magic)) {
101 			err = got_error(GOT_ERR_BAD_PACKIDX);
102 			goto done;
103 		}
104 	}
105 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
106 		err = got_error(GOT_ERR_BAD_PACKIDX);
107 		goto done;
108 	}
109 	offset += sizeof(*h->magic);
110 	remain -= sizeof(*h->magic);
111 
112 	if (verify)
113 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
114 
115 	if (remain < sizeof(*h->version)) {
116 		err = got_error(GOT_ERR_BAD_PACKIDX);
117 		goto done;
118 	}
119 	if (p->map)
120 		h->version = (uint32_t *)(p->map + offset);
121 	else {
122 		h->version = malloc(sizeof(*h->version));
123 		if (h->version == NULL) {
124 			err = got_error_from_errno("malloc");
125 			goto done;
126 		}
127 		n = read(p->fd, h->version, sizeof(*h->version));
128 		if (n < 0)
129 			err = got_error_from_errno("read");
130 		else if (n != sizeof(*h->version)) {
131 			err = got_error(GOT_ERR_BAD_PACKIDX);
132 			goto done;
133 		}
134 	}
135 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
136 		err = got_error(GOT_ERR_BAD_PACKIDX);
137 		goto done;
138 	}
139 	offset += sizeof(*h->version);
140 	remain -= sizeof(*h->version);
141 
142 	if (verify)
143 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
144 
145 	len_fanout =
146 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
147 	if (remain < len_fanout) {
148 		err = got_error(GOT_ERR_BAD_PACKIDX);
149 		goto done;
150 	}
151 	if (p->map)
152 		h->fanout_table = (uint32_t *)(p->map + offset);
153 	else {
154 		h->fanout_table = malloc(len_fanout);
155 		if (h->fanout_table == NULL) {
156 			err = got_error_from_errno("malloc");
157 			goto done;
158 		}
159 		n = read(p->fd, h->fanout_table, len_fanout);
160 		if (n < 0)
161 			err = got_error_from_errno("read");
162 		else if (n != len_fanout) {
163 			err = got_error(GOT_ERR_BAD_PACKIDX);
164 			goto done;
165 		}
166 	}
167 	err = verify_fanout_table(h->fanout_table);
168 	if (err)
169 		goto done;
170 	if (verify)
171 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
172 	offset += len_fanout;
173 	remain -= len_fanout;
174 
175 	nobj = betoh32(h->fanout_table[0xff]);
176 	len_ids = nobj * sizeof(*h->sorted_ids);
177 	if (len_ids <= nobj || len_ids > remain) {
178 		err = got_error(GOT_ERR_BAD_PACKIDX);
179 		goto done;
180 	}
181 	if (p->map)
182 		h->sorted_ids =
183 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
184 	else {
185 		h->sorted_ids = malloc(len_ids);
186 		if (h->sorted_ids == NULL) {
187 			err = got_error(GOT_ERR_BAD_PACKIDX);
188 			goto done;
189 		}
190 		n = read(p->fd, h->sorted_ids, len_ids);
191 		if (n < 0)
192 			err = got_error_from_errno("read");
193 		else if (n != len_ids) {
194 			err = got_error(GOT_ERR_BAD_PACKIDX);
195 			goto done;
196 		}
197 	}
198 	if (verify)
199 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
200 	offset += len_ids;
201 	remain -= len_ids;
202 
203 	if (remain < nobj * sizeof(*h->crc32)) {
204 		err = got_error(GOT_ERR_BAD_PACKIDX);
205 		goto done;
206 	}
207 	if (p->map)
208 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
209 	else {
210 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
211 		if (h->crc32 == NULL) {
212 			err = got_error_from_errno("malloc");
213 			goto done;
214 		}
215 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
216 		if (n < 0)
217 			err = got_error_from_errno("read");
218 		else if (n != nobj * sizeof(*h->crc32)) {
219 			err = got_error(GOT_ERR_BAD_PACKIDX);
220 			goto done;
221 		}
222 	}
223 	if (verify)
224 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
225 	remain -= nobj * sizeof(*h->crc32);
226 	offset += nobj * sizeof(*h->crc32);
227 
228 	if (remain < nobj * sizeof(*h->offsets)) {
229 		err = got_error(GOT_ERR_BAD_PACKIDX);
230 		goto done;
231 	}
232 	if (p->map)
233 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
234 	else {
235 		h->offsets = malloc(nobj * sizeof(*h->offsets));
236 		if (h->offsets == NULL) {
237 			err = got_error_from_errno("malloc");
238 			goto done;
239 		}
240 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
241 		if (n < 0)
242 			err = got_error_from_errno("read");
243 		else if (n != nobj * sizeof(*h->offsets)) {
244 			err = got_error(GOT_ERR_BAD_PACKIDX);
245 			goto done;
246 		}
247 	}
248 	if (verify)
249 		SHA1Update(&ctx, (uint8_t *)h->offsets,
250 		    nobj * sizeof(*h->offsets));
251 	remain -= nobj * sizeof(*h->offsets);
252 	offset += nobj * sizeof(*h->offsets);
253 
254 	/* Large file offsets are contained only in files > 2GB. */
255 	if (p->len <= 0x80000000)
256 		goto checksum;
257 
258 	if (remain < nobj * sizeof(*h->large_offsets)) {
259 		err = got_error(GOT_ERR_BAD_PACKIDX);
260 		goto done;
261 	}
262 	if (p->map)
263 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
264 	else {
265 		h->large_offsets = malloc(nobj * sizeof(*h->large_offsets));
266 		if (h->large_offsets == NULL) {
267 			err = got_error_from_errno("malloc");
268 			goto done;
269 		}
270 		n = read(p->fd, h->large_offsets,
271 		    nobj * sizeof(*h->large_offsets));
272 		if (n < 0)
273 			err = got_error_from_errno("read");
274 		else if (n != nobj * sizeof(*h->large_offsets)) {
275 			err = got_error(GOT_ERR_BAD_PACKIDX);
276 			goto done;
277 		}
278 	}
279 	if (verify)
280 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
281 		    nobj * sizeof(*h->large_offsets));
282 	remain -= nobj * sizeof(*h->large_offsets);
283 	offset += nobj * sizeof(*h->large_offsets);
284 
285 checksum:
286 	if (remain < sizeof(*h->trailer)) {
287 		err = got_error(GOT_ERR_BAD_PACKIDX);
288 		goto done;
289 	}
290 	if (p->map)
291 		h->trailer =
292 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
293 	else {
294 		h->trailer = malloc(sizeof(*h->trailer));
295 		if (h->trailer == NULL) {
296 			err = got_error_from_errno("malloc");
297 			goto done;
298 		}
299 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
300 		if (n < 0)
301 			err = got_error_from_errno("read");
302 		else if (n != sizeof(*h->trailer)) {
303 			err = got_error(GOT_ERR_BAD_PACKIDX);
304 			goto done;
305 		}
306 	}
307 	if (verify) {
308 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
309 		SHA1Final(sha1, &ctx);
310 		if (memcmp(h->trailer->packidx_sha1, sha1,
311 		    SHA1_DIGEST_LENGTH) != 0)
312 			err = got_error(GOT_ERR_PACKIDX_CSUM);
313 	}
314 done:
315 	return err;
316 }
317 
318 const struct got_error *
319 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
320 {
321 	const struct got_error *err = NULL;
322 	struct got_packidx *p;
323 	struct stat sb;
324 
325 	*packidx = NULL;
326 
327 	p = calloc(1, sizeof(*p));
328 	if (p == NULL)
329 		return got_error_from_errno("calloc");
330 
331 	p->fd = open(path, O_RDONLY | O_NOFOLLOW);
332 	if (p->fd == -1) {
333 		err = got_error_from_errno2("open", path);
334 		free(p);
335 		return err;
336 	}
337 
338 	if (fstat(p->fd, &sb) != 0) {
339 		err = got_error_from_errno2("fstat", path);
340 		close(p->fd);
341 		free(p);
342 		return err;
343 	}
344 	p->len = sb.st_size;
345 	if (p->len < sizeof(p->hdr)) {
346 		err = got_error(GOT_ERR_BAD_PACKIDX);
347 		close(p->fd);
348 		free(p);
349 		return err;
350 	}
351 
352 	p->path_packidx = strdup(path);
353 	if (p->path_packidx == NULL) {
354 		err = got_error_from_errno("strdup");
355 		goto done;
356 	}
357 
358 #ifndef GOT_PACK_NO_MMAP
359 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
360 	if (p->map == MAP_FAILED) {
361 		if (errno != ENOMEM) {
362 			err = got_error_from_errno("mmap");
363 			goto done;
364 		}
365 		p->map = NULL; /* fall back to read(2) */
366 	}
367 #endif
368 
369 	err = got_packidx_init_hdr(p, verify);
370 done:
371 	if (err)
372 		got_packidx_close(p);
373 	else
374 		*packidx = p;
375 
376 	return err;
377 }
378 
379 const struct got_error *
380 got_packidx_close(struct got_packidx *packidx)
381 {
382 	const struct got_error *err = NULL;
383 
384 	free(packidx->path_packidx);
385 	if (packidx->map) {
386 		if (munmap(packidx->map, packidx->len) == -1)
387 			err = got_error_from_errno("munmap");
388 	} else {
389 		free(packidx->hdr.magic);
390 		free(packidx->hdr.version);
391 		free(packidx->hdr.fanout_table);
392 		free(packidx->hdr.sorted_ids);
393 		free(packidx->hdr.crc32);
394 		free(packidx->hdr.offsets);
395 		free(packidx->hdr.large_offsets);
396 		free(packidx->hdr.trailer);
397 	}
398 	if (close(packidx->fd) != 0 && err == NULL)
399 		err = got_error_from_errno("close");
400 	free(packidx);
401 
402 	return err;
403 }
404 
405 static off_t
406 get_object_offset(struct got_packidx *packidx, int idx)
407 {
408 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
409 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
410 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
411 		uint64_t loffset;
412 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
413 		if (idx < 0 || idx > totobj ||
414 		    packidx->hdr.large_offsets == NULL)
415 			return -1;
416 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
417 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
418 	}
419 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
420 }
421 
422 int
423 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
424 {
425 	u_int8_t id0 = id->sha1[0];
426 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
427 	int left = 0, right = totobj - 1;
428 
429 	if (id0 > 0)
430 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
431 
432 	while (left <= right) {
433 		struct got_packidx_object_id *oid;
434 		int i, cmp;
435 
436 		i = ((left + right) / 2);
437 		oid = &packidx->hdr.sorted_ids[i];
438 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
439 		if (cmp == 0)
440 			return i;
441 		else if (cmp > 0)
442 			left = i + 1;
443 		else if (cmp < 0)
444 			right = i - 1;
445 	}
446 
447 	return -1;
448 }
449 
450 const struct got_error *
451 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
452     struct got_packidx *packidx, const char *id_str_prefix)
453 {
454 	const struct got_error *err = NULL;
455 	u_int8_t id0;
456 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
457 	char hex[3];
458 	size_t prefix_len = strlen(id_str_prefix);
459 	struct got_packidx_object_id *oid;
460 	int i;
461 
462 	SIMPLEQ_INIT(matched_ids);
463 
464 	if (prefix_len < 2)
465 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
466 
467 	hex[0] = id_str_prefix[0];
468 	hex[1] = id_str_prefix[1];
469 	hex[2] = '\0';
470 	if (!got_parse_xdigit(&id0, hex))
471 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
472 
473 	i = betoh32(packidx->hdr.fanout_table[id0 - 1]);
474 	if (i == 0)
475 		return NULL;
476 
477 	oid = &packidx->hdr.sorted_ids[i];
478 	while (i < totobj && oid->sha1[0] == id0) {
479 		char id_str[SHA1_DIGEST_STRING_LENGTH];
480 		struct got_object_qid *qid;
481 		int cmp;
482 
483 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
484 		        return got_error(GOT_ERR_NO_SPACE);
485 
486 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
487 		if (cmp < 0) {
488 			oid = &packidx->hdr.sorted_ids[++i];
489 			continue;
490 		} else if (cmp > 0)
491 			break;
492 
493 		err = got_object_qid_alloc_partial(&qid);
494 		if (err)
495 			break;
496 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
497 		SIMPLEQ_INSERT_TAIL(matched_ids, qid, entry);
498 
499 		oid = &packidx->hdr.sorted_ids[++i];
500 	}
501 
502 	if (err)
503 		got_object_id_queue_free(matched_ids);
504 	return err;
505 }
506 
507 const struct got_error *
508 got_pack_stop_privsep_child(struct got_pack *pack)
509 {
510 	const struct got_error *err = NULL;
511 
512 	if (pack->privsep_child == NULL)
513 		return NULL;
514 
515 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
516 	if (err)
517 		return err;
518 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
519 	if (close(pack->privsep_child->imsg_fd) != 0 && err == NULL)
520 		err = got_error_from_errno("close");
521 	free(pack->privsep_child);
522 	pack->privsep_child = NULL;
523 	return err;
524 }
525 
526 const struct got_error *
527 got_pack_close(struct got_pack *pack)
528 {
529 	const struct got_error *err = NULL;
530 
531 	err = got_pack_stop_privsep_child(pack);
532 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
533 		err = got_error_from_errno("munmap");
534 	if (pack->fd != -1 && close(pack->fd) != 0 && err == NULL)
535 		err = got_error_from_errno("close");
536 	pack->fd = -1;
537 	free(pack->path_packfile);
538 	pack->path_packfile = NULL;
539 	pack->filesize = 0;
540 
541 	return err;
542 }
543 
544 static const struct got_error *
545 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
546     struct got_pack *pack, off_t offset)
547 {
548 	uint8_t t = 0;
549 	uint64_t s = 0;
550 	uint8_t sizeN;
551 	size_t mapoff = 0;
552 	int i = 0;
553 
554 	*len = 0;
555 
556 	if (offset >= pack->filesize)
557 		return got_error(GOT_ERR_PACK_OFFSET);
558 
559 	if (pack->map) {
560 		mapoff = (size_t)offset;
561 	} else {
562 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
563 			return got_error_from_errno("lseek");
564 	}
565 
566 	do {
567 		/* We do not support size values which don't fit in 64 bit. */
568 		if (i > 9)
569 			return got_error(GOT_ERR_NO_SPACE);
570 
571 		if (pack->map) {
572 			sizeN = *(pack->map + mapoff);
573 			mapoff += sizeof(sizeN);
574 		} else {
575 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
576 			if (n < 0)
577 				return got_error_from_errno("read");
578 			if (n != sizeof(sizeN))
579 				return got_error(GOT_ERR_BAD_PACKFILE);
580 		}
581 		*len += sizeof(sizeN);
582 
583 		if (i == 0) {
584 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
585 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
586 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
587 		} else {
588 			size_t shift = 4 + 7 * (i - 1);
589 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
590 		}
591 		i++;
592 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
593 
594 	*type = t;
595 	*size = s;
596 	return NULL;
597 }
598 
599 static const struct got_error *
600 open_plain_object(struct got_object **obj, const char *path_packfile,
601     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
602 {
603 	*obj = calloc(1, sizeof(**obj));
604 	if (*obj == NULL)
605 		return got_error_from_errno("calloc");
606 
607 	(*obj)->path_packfile = strdup(path_packfile);
608 	if ((*obj)->path_packfile == NULL) {
609 		const struct got_error *err = got_error_from_errno("strdup");
610 		free(*obj);
611 		*obj = NULL;
612 		return err;
613 	}
614 
615 	(*obj)->type = type;
616 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
617 	(*obj)->pack_idx = idx;
618 	(*obj)->hdrlen = 0;
619 	(*obj)->size = size;
620 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
621 	(*obj)->pack_offset = offset;
622 
623 	return NULL;
624 }
625 
626 static const struct got_error *
627 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
628     off_t delta_offset)
629 {
630 	int64_t o = 0;
631 	uint8_t offN;
632 	int i = 0;
633 
634 	*offset = 0;
635 	*len = 0;
636 
637 	do {
638 		/* We do not support offset values which don't fit in 64 bit. */
639 		if (i > 8)
640 			return got_error(GOT_ERR_NO_SPACE);
641 
642 		if (pack->map) {
643 			size_t mapoff;
644 			if (delta_offset >= pack->filesize)
645 				return got_error(GOT_ERR_PACK_OFFSET);
646 			mapoff = (size_t)delta_offset + *len;
647 			offN = *(pack->map + mapoff);
648 		} else {
649 			ssize_t n;
650 			n = read(pack->fd, &offN, sizeof(offN));
651 			if (n < 0)
652 				return got_error_from_errno("read");
653 			if (n != sizeof(offN))
654 				return got_error(GOT_ERR_BAD_PACKFILE);
655 		}
656 		*len += sizeof(offN);
657 
658 		if (i == 0)
659 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
660 		else {
661 			o++;
662 			o <<= 7;
663 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
664 		}
665 		i++;
666 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
667 
668 	*offset = o;
669 	return NULL;
670 }
671 
672 static const struct got_error *
673 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
674     off_t offset, int tslen)
675 {
676 	const struct got_error *err;
677 	int64_t negoffset;
678 	size_t negofflen;
679 
680 	*len = 0;
681 
682 	err = parse_negative_offset(&negoffset, &negofflen, pack,
683 	    offset + tslen);
684 	if (err)
685 		return err;
686 
687 	/* Compute the base object's offset (must be in the same pack file). */
688 	*base_offset = (offset - negoffset);
689 	if (*base_offset <= 0)
690 		return got_error(GOT_ERR_BAD_PACKFILE);
691 
692 	*len = negofflen;
693 	return NULL;
694 }
695 
696 static const struct got_error *
697 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
698     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
699 
700 static const struct got_error *
701 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
702     int delta_type, size_t delta_size, size_t delta_data_offset,
703     uint8_t *delta_buf, size_t delta_len)
704 {
705 	struct got_delta *delta;
706 
707 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
708 	    delta_data_offset, delta_buf,
709 	    delta_len);
710 	if (delta == NULL)
711 		return got_error_from_errno("got_delta_open");
712 	/* delta is freed in got_object_close() */
713 	deltas->nentries++;
714 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
715 	return NULL;
716 }
717 
718 static const struct got_error *
719 resolve_offset_delta(struct got_delta_chain *deltas,
720     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
721     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
722 
723 {
724 	const struct got_error *err;
725 	off_t base_offset;
726 	uint8_t base_type;
727 	uint64_t base_size;
728 	size_t base_tslen;
729 	off_t delta_data_offset;
730 	uint8_t *delta_buf;
731 	size_t delta_len, consumed;
732 
733 	err = parse_offset_delta(&base_offset, &consumed, pack,
734 	    delta_offset, tslen);
735 	if (err)
736 		return err;
737 
738 	delta_data_offset = delta_offset + tslen + consumed;
739 	if (delta_data_offset >= pack->filesize)
740 		return got_error(GOT_ERR_PACK_OFFSET);
741 
742 	if (pack->map == NULL) {
743 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
744 		if (delta_data_offset == -1)
745 			return got_error_from_errno("lseek");
746 	}
747 
748 	if (pack->map) {
749 		size_t mapoff = (size_t)delta_data_offset;
750 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
751 		    mapoff, pack->filesize - mapoff);
752 		if (err)
753 			return err;
754 	} else {
755 
756 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
757 		if (err)
758 			return err;
759 	}
760 
761 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
762 	    delta_data_offset, delta_buf, delta_len);
763 	if (err)
764 		return err;
765 
766 	/* An offset delta must be in the same packfile. */
767 	if (base_offset >= pack->filesize)
768 		return got_error(GOT_ERR_PACK_OFFSET);
769 
770 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
771 	    pack, base_offset);
772 	if (err)
773 		return err;
774 
775 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
776 	    base_tslen, base_type, base_size, recursion - 1);
777 }
778 
779 static const struct got_error *
780 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
781     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
782     size_t delta_size, unsigned int recursion)
783 {
784 	const struct got_error *err;
785 	struct got_object_id id;
786 	int idx;
787 	off_t base_offset;
788 	uint8_t base_type;
789 	uint64_t base_size;
790 	size_t base_tslen;
791 	off_t delta_data_offset;
792 	uint8_t *delta_buf;
793 	size_t delta_len;
794 
795 	if (delta_offset >= pack->filesize)
796 		return got_error(GOT_ERR_PACK_OFFSET);
797 	delta_data_offset = delta_offset + tslen;
798 	if (delta_data_offset >= pack->filesize)
799 		return got_error(GOT_ERR_PACK_OFFSET);
800 
801 	if (pack->map == NULL) {
802 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
803 		if (delta_data_offset == -1)
804 			return got_error_from_errno("lseek");
805 	}
806 
807 	if (pack->map) {
808 		size_t mapoff = (size_t)delta_data_offset;
809 		memcpy(&id, pack->map + mapoff, sizeof(id));
810 		mapoff += sizeof(id);
811 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
812 		    mapoff, pack->filesize - mapoff);
813 		if (err)
814 			return err;
815 	} else {
816 		ssize_t n = read(pack->fd, &id, sizeof(id));
817 		if (n < 0)
818 			return got_error_from_errno("read");
819 		if (n != sizeof(id))
820 			return got_error(GOT_ERR_BAD_PACKFILE);
821 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
822 		if (err)
823 			return err;
824 	}
825 
826 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
827 	    delta_data_offset, delta_buf, delta_len);
828 	if (err)
829 		return err;
830 
831 	/* Delta base must be in the same pack file. */
832 	idx = got_packidx_get_object_idx(packidx, &id);
833 	if (idx == -1)
834 		return got_error(GOT_ERR_BAD_PACKFILE);
835 
836 	base_offset = get_object_offset(packidx, idx);
837 	if (base_offset == (uint64_t)-1)
838 		return got_error(GOT_ERR_BAD_PACKIDX);
839 
840 	if (base_offset >= pack->filesize)
841 		return got_error(GOT_ERR_PACK_OFFSET);
842 
843 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
844 	    pack, base_offset);
845 	if (err)
846 		return err;
847 
848 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
849 	    base_tslen, base_type, base_size, recursion - 1);
850 }
851 
852 static const struct got_error *
853 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
854     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
855     size_t delta_size, unsigned int recursion)
856 {
857 	const struct got_error *err = NULL;
858 
859 	if (--recursion == 0)
860 		return got_error(GOT_ERR_RECURSION);
861 
862 	switch (delta_type) {
863 	case GOT_OBJ_TYPE_COMMIT:
864 	case GOT_OBJ_TYPE_TREE:
865 	case GOT_OBJ_TYPE_BLOB:
866 	case GOT_OBJ_TYPE_TAG:
867 		/* Plain types are the final delta base. Recursion ends. */
868 		err = add_delta(deltas, delta_offset, tslen, delta_type,
869 		    delta_size, 0, NULL, 0);
870 		break;
871 	case GOT_OBJ_TYPE_OFFSET_DELTA:
872 		err = resolve_offset_delta(deltas, packidx, pack,
873 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
874 		break;
875 	case GOT_OBJ_TYPE_REF_DELTA:
876 		err = resolve_ref_delta(deltas, packidx, pack,
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_packidx *packidx,
888     struct got_pack *pack, struct got_object_id *id, off_t offset,
889     size_t tslen, int delta_type, size_t delta_size, int idx)
890 {
891 	const struct got_error *err = NULL;
892 	int resolved_type;
893 
894 	*obj = calloc(1, sizeof(**obj));
895 	if (*obj == NULL)
896 		return got_error_from_errno("calloc");
897 
898 	(*obj)->flags = 0;
899 	(*obj)->hdrlen = 0;
900 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
901 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
902 	(*obj)->pack_offset = offset + tslen;
903 
904 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
905 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
906 
907 	(*obj)->path_packfile = strdup(pack->path_packfile);
908 	if ((*obj)->path_packfile == NULL) {
909 		err = got_error_from_errno("strdup");
910 		goto done;
911 	}
912 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
913 	(*obj)->pack_idx = idx;
914 
915 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
916 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
917 	if (err)
918 		goto done;
919 
920 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
921 	if (err)
922 		goto done;
923 	(*obj)->type = resolved_type;
924 done:
925 	if (err) {
926 		got_object_close(*obj);
927 		*obj = NULL;
928 	}
929 	return err;
930 }
931 
932 const struct got_error *
933 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
934     struct got_packidx *packidx, int idx, struct got_object_id *id)
935 {
936 	const struct got_error *err = NULL;
937 	off_t offset;
938 	uint8_t type;
939 	uint64_t size;
940 	size_t tslen;
941 
942 	*obj = NULL;
943 
944 	offset = get_object_offset(packidx, idx);
945 	if (offset == (uint64_t)-1)
946 		return got_error(GOT_ERR_BAD_PACKIDX);
947 
948 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
949 	if (err)
950 		return err;
951 
952 	switch (type) {
953 	case GOT_OBJ_TYPE_COMMIT:
954 	case GOT_OBJ_TYPE_TREE:
955 	case GOT_OBJ_TYPE_BLOB:
956 	case GOT_OBJ_TYPE_TAG:
957 		err = open_plain_object(obj, pack->path_packfile, id, type,
958 		    offset + tslen, size, idx);
959 		break;
960 	case GOT_OBJ_TYPE_OFFSET_DELTA:
961 	case GOT_OBJ_TYPE_REF_DELTA:
962 		err = open_delta_object(obj, packidx, pack, id, offset,
963 		    tslen, type, size, idx);
964 		break;
965 	default:
966 		err = got_error(GOT_ERR_OBJ_TYPE);
967 		break;
968 	}
969 
970 	return err;
971 }
972 
973 static const struct got_error *
974 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
975 {
976 	struct got_delta *delta;
977 	uint64_t base_size = 0, result_size = 0;
978 
979 	*max_size = 0;
980 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
981 		/* Plain object types are the delta base. */
982 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
983 		    delta->type != GOT_OBJ_TYPE_TREE &&
984 		    delta->type != GOT_OBJ_TYPE_BLOB &&
985 		    delta->type != GOT_OBJ_TYPE_TAG) {
986 			const struct got_error *err;
987 			err = got_delta_get_sizes(&base_size, &result_size,
988 			    delta->delta_buf, delta->delta_len);
989 			if (err)
990 				return err;
991 		} else
992 			base_size = delta->size;
993 		if (base_size > *max_size)
994 			*max_size = base_size;
995 		if (result_size > *max_size)
996 			*max_size = result_size;
997 	}
998 
999 	return NULL;
1000 }
1001 
1002 const struct got_error *
1003 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj)
1004 {
1005 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1006 		return got_error(GOT_ERR_OBJ_TYPE);
1007 
1008 	return get_delta_chain_max_size(size, &obj->deltas);
1009 }
1010 
1011 static const struct got_error *
1012 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1013     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
1014 {
1015 	const struct got_error *err = NULL;
1016 	struct got_delta *delta;
1017 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1018 	size_t base_bufsz = 0, accum_size = 0;
1019 	uint64_t max_size;
1020 	int n = 0;
1021 
1022 	*result_size = 0;
1023 
1024 	if (SIMPLEQ_EMPTY(&deltas->entries))
1025 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1026 
1027 	/* We process small enough files entirely in memory for speed. */
1028 	err = get_delta_chain_max_size(&max_size, deltas);
1029 	if (err)
1030 		return err;
1031 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1032 		accum_buf = malloc(max_size);
1033 		if (accum_buf == NULL)
1034 			return got_error_from_errno("malloc");
1035 		base_file = NULL;
1036 		accum_file = NULL;
1037 	}
1038 
1039 	/* Deltas are ordered in ascending order. */
1040 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1041 		if (n == 0) {
1042 			size_t mapoff;
1043 			off_t delta_data_offset;
1044 
1045 			/* Plain object types are the delta base. */
1046 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1047 			    delta->type != GOT_OBJ_TYPE_TREE &&
1048 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1049 			    delta->type != GOT_OBJ_TYPE_TAG) {
1050 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1051 				goto done;
1052 			}
1053 
1054 			delta_data_offset = delta->offset + delta->tslen;
1055 			if (delta_data_offset >= pack->filesize) {
1056 				err = got_error(GOT_ERR_PACK_OFFSET);
1057 				goto done;
1058 			}
1059 			if (pack->map == NULL) {
1060 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1061 				    == -1) {
1062 					err = got_error_from_errno("lseek");
1063 					goto done;
1064 				}
1065 			}
1066 			if (base_file) {
1067 				if (pack->map) {
1068 					mapoff = (size_t)delta_data_offset;
1069 					err = got_inflate_to_file_mmap(
1070 					    &base_bufsz, pack->map, mapoff,
1071 					    pack->filesize - mapoff, base_file);
1072 				} else
1073 					err = got_inflate_to_file_fd(
1074 					    &base_bufsz, pack->fd, base_file);
1075 			} else {
1076 				if (pack->map) {
1077 					mapoff = (size_t)delta_data_offset;
1078 					err = got_inflate_to_mem_mmap(&base_buf,
1079 					    &base_bufsz, pack->map, mapoff,
1080 					    pack->filesize - mapoff);
1081 				} else
1082 					err = got_inflate_to_mem_fd(&base_buf,
1083 					    &base_bufsz, pack->fd);
1084 			}
1085 			if (err)
1086 				goto done;
1087 			n++;
1088 			if (base_file)
1089 				rewind(base_file);
1090 			continue;
1091 		}
1092 
1093 		if (base_buf) {
1094 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1095 			    delta->delta_buf, delta->delta_len, accum_buf,
1096 			    &accum_size, max_size);
1097 			n++;
1098 		} else {
1099 			err = got_delta_apply(base_file, delta->delta_buf,
1100 			    delta->delta_len,
1101 			    /* Final delta application writes to output file. */
1102 			    ++n < deltas->nentries ? accum_file : outfile,
1103 			    &accum_size);
1104 		}
1105 		if (err)
1106 			goto done;
1107 
1108 		if (n < deltas->nentries) {
1109 			/* Accumulated delta becomes the new base. */
1110 			if (base_buf) {
1111 				uint8_t *tmp = accum_buf;
1112 				/*
1113 				 * Base buffer switches roles with accumulation
1114 				 * buffer. Ensure it can hold the largest
1115 				 * result in the delta chain. The initial
1116 				 * allocation might have been smaller.
1117 				 */
1118 				if (base_bufsz < max_size) {
1119 					uint8_t *p;
1120 					p = reallocarray(base_buf, 1, max_size);
1121 					if (p == NULL) {
1122 						err = got_error_from_errno(
1123 						    "reallocarray");
1124 						goto done;
1125 					}
1126 					base_buf = p;
1127 					base_bufsz = max_size;
1128 				}
1129 				accum_buf = base_buf;
1130 				base_buf = tmp;
1131 			} else {
1132 				FILE *tmp = accum_file;
1133 				accum_file = base_file;
1134 				base_file = tmp;
1135 				rewind(base_file);
1136 				rewind(accum_file);
1137 			}
1138 		}
1139 	}
1140 
1141 done:
1142 	free(base_buf);
1143 	if (accum_buf) {
1144 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1145 		free(accum_buf);
1146 		if (len != accum_size)
1147 			err = got_ferror(outfile, GOT_ERR_IO);
1148 	}
1149 	rewind(outfile);
1150 	if (err == NULL)
1151 		*result_size = accum_size;
1152 	return err;
1153 }
1154 
1155 static const struct got_error *
1156 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1157     struct got_delta_chain *deltas, struct got_pack *pack)
1158 {
1159 	const struct got_error *err = NULL;
1160 	struct got_delta *delta;
1161 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1162 	size_t base_bufsz = 0, accum_size = 0;
1163 	uint64_t max_size;
1164 	int n = 0;
1165 
1166 	*outbuf = NULL;
1167 	*outlen = 0;
1168 
1169 	if (SIMPLEQ_EMPTY(&deltas->entries))
1170 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1171 
1172 	err = get_delta_chain_max_size(&max_size, deltas);
1173 	if (err)
1174 		return err;
1175 	accum_buf = malloc(max_size);
1176 	if (accum_buf == NULL)
1177 		return got_error_from_errno("malloc");
1178 
1179 	/* Deltas are ordered in ascending order. */
1180 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1181 		if (n == 0) {
1182 			size_t delta_data_offset;
1183 
1184 			/* Plain object types are the delta base. */
1185 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1186 			    delta->type != GOT_OBJ_TYPE_TREE &&
1187 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1188 			    delta->type != GOT_OBJ_TYPE_TAG) {
1189 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1190 				goto done;
1191 			}
1192 
1193 			delta_data_offset = delta->offset + delta->tslen;
1194 			if (delta_data_offset >= pack->filesize) {
1195 				err = got_error(GOT_ERR_PACK_OFFSET);
1196 				goto done;
1197 			}
1198 			if (pack->map) {
1199 				size_t mapoff = (size_t)delta_data_offset;
1200 				err = got_inflate_to_mem_mmap(&base_buf,
1201 				    &base_bufsz, pack->map, mapoff,
1202 				    pack->filesize - mapoff);
1203 			} else {
1204 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1205 				    == -1) {
1206 					err = got_error_from_errno("lseek");
1207 					goto done;
1208 				}
1209 				err = got_inflate_to_mem_fd(&base_buf,
1210 				    &base_bufsz, pack->fd);
1211 			}
1212 			if (err)
1213 				goto done;
1214 			n++;
1215 			continue;
1216 		}
1217 
1218 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1219 		    delta->delta_buf, delta->delta_len, accum_buf,
1220 		    &accum_size, max_size);
1221 		n++;
1222 		if (err)
1223 			goto done;
1224 
1225 		if (n < deltas->nentries) {
1226 			/* Accumulated delta becomes the new base. */
1227 			uint8_t *tmp = accum_buf;
1228 			/*
1229 			 * Base buffer switches roles with accumulation buffer.
1230 			 * Ensure it can hold the largest result in the delta
1231 			 * chain. Initial allocation might have been smaller.
1232 			 */
1233 			if (base_bufsz < max_size) {
1234 				uint8_t *p;
1235 				p = reallocarray(base_buf, 1, max_size);
1236 				if (p == NULL) {
1237 					err = got_error_from_errno(
1238 					    "reallocarray");
1239 					goto done;
1240 				}
1241 				base_buf = p;
1242 				base_bufsz = max_size;
1243 			}
1244 			accum_buf = base_buf;
1245 			base_buf = tmp;
1246 		}
1247 	}
1248 
1249 done:
1250 	free(base_buf);
1251 	if (err) {
1252 		free(accum_buf);
1253 		*outbuf = NULL;
1254 		*outlen = 0;
1255 	} else {
1256 		*outbuf = accum_buf;
1257 		*outlen = accum_size;
1258 	}
1259 	return err;
1260 }
1261 
1262 const struct got_error *
1263 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1264     FILE *outfile, FILE *base_file, FILE *accum_file)
1265 {
1266 	const struct got_error *err = NULL;
1267 
1268 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1269 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1270 
1271 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1272 		if (obj->pack_offset >= pack->filesize)
1273 			return got_error(GOT_ERR_PACK_OFFSET);
1274 
1275 		if (pack->map) {
1276 			size_t mapoff = (size_t)obj->pack_offset;
1277 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1278 			    mapoff, pack->filesize - mapoff, outfile);
1279 		} else {
1280 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1281 				return got_error_from_errno("lseek");
1282 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1283 			    outfile);
1284 		}
1285 	} else
1286 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1287 		    outfile, base_file, accum_file);
1288 
1289 	return err;
1290 }
1291 
1292 const struct got_error *
1293 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1294     struct got_object *obj, struct got_pack *pack)
1295 {
1296 	const struct got_error *err = NULL;
1297 
1298 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1299 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1300 
1301 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1302 		if (obj->pack_offset >= pack->filesize)
1303 			return got_error(GOT_ERR_PACK_OFFSET);
1304 		if (pack->map) {
1305 			size_t mapoff = (size_t)obj->pack_offset;
1306 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1307 			    mapoff, pack->filesize - mapoff);
1308 		} else {
1309 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1310 				return got_error_from_errno("lseek");
1311 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1312 		}
1313 	} else
1314 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1315 
1316 	return err;
1317 }