Game of Trees Repos

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Date:: Sun Nov 10 11:32:03 2019 UTC
Message:: when an object id string is bad, include the bad string in the error message
Actions:: History | Blame | Raw File
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 	int i;
79 
80 	SHA1Init(&ctx);
81 
82 	h = &p->hdr;
83 	offset = 0;
84 	remain = p->len;
85 
86 	if (remain < sizeof(*h->magic)) {
87 		err = got_error(GOT_ERR_BAD_PACKIDX);
88 		goto done;
89 	}
90 	if (p->map)
91 		h->magic = (uint32_t *)(p->map + offset);
92 	else {
93 		h->magic = malloc(sizeof(*h->magic));
94 		if (h->magic == NULL) {
95 			err = got_error_from_errno("malloc");
96 			goto done;
97 		}
98 		n = read(p->fd, h->magic, sizeof(*h->magic));
99 		if (n < 0) {
100 			err = got_error_from_errno("read");
101 			goto done;
102 		} else if (n != sizeof(*h->magic)) {
103 			err = got_error(GOT_ERR_BAD_PACKIDX);
104 			goto done;
105 		}
106 	}
107 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
108 		err = got_error(GOT_ERR_BAD_PACKIDX);
109 		goto done;
110 	}
111 	offset += sizeof(*h->magic);
112 	remain -= sizeof(*h->magic);
113 
114 	if (verify)
115 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
116 
117 	if (remain < sizeof(*h->version)) {
118 		err = got_error(GOT_ERR_BAD_PACKIDX);
119 		goto done;
120 	}
121 	if (p->map)
122 		h->version = (uint32_t *)(p->map + offset);
123 	else {
124 		h->version = malloc(sizeof(*h->version));
125 		if (h->version == NULL) {
126 			err = got_error_from_errno("malloc");
127 			goto done;
128 		}
129 		n = read(p->fd, h->version, sizeof(*h->version));
130 		if (n < 0) {
131 			err = got_error_from_errno("read");
132 			goto done;
133 		} else if (n != sizeof(*h->version)) {
134 			err = got_error(GOT_ERR_BAD_PACKIDX);
135 			goto done;
136 		}
137 	}
138 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
139 		err = got_error(GOT_ERR_BAD_PACKIDX);
140 		goto done;
141 	}
142 	offset += sizeof(*h->version);
143 	remain -= sizeof(*h->version);
144 
145 	if (verify)
146 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
147 
148 	len_fanout =
149 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
150 	if (remain < len_fanout) {
151 		err = got_error(GOT_ERR_BAD_PACKIDX);
152 		goto done;
153 	}
154 	if (p->map)
155 		h->fanout_table = (uint32_t *)(p->map + offset);
156 	else {
157 		h->fanout_table = malloc(len_fanout);
158 		if (h->fanout_table == NULL) {
159 			err = got_error_from_errno("malloc");
160 			goto done;
161 		}
162 		n = read(p->fd, h->fanout_table, len_fanout);
163 		if (n < 0) {
164 			err = got_error_from_errno("read");
165 			goto done;
166 		} else if (n != len_fanout) {
167 			err = got_error(GOT_ERR_BAD_PACKIDX);
168 			goto done;
169 		}
170 	}
171 	err = verify_fanout_table(h->fanout_table);
172 	if (err)
173 		goto done;
174 	if (verify)
175 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
176 	offset += len_fanout;
177 	remain -= len_fanout;
178 
179 	nobj = betoh32(h->fanout_table[0xff]);
180 	len_ids = nobj * sizeof(*h->sorted_ids);
181 	if (len_ids <= nobj || len_ids > remain) {
182 		err = got_error(GOT_ERR_BAD_PACKIDX);
183 		goto done;
184 	}
185 	if (p->map)
186 		h->sorted_ids =
187 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
188 	else {
189 		h->sorted_ids = malloc(len_ids);
190 		if (h->sorted_ids == NULL) {
191 			err = got_error(GOT_ERR_BAD_PACKIDX);
192 			goto done;
193 		}
194 		n = read(p->fd, h->sorted_ids, len_ids);
195 		if (n < 0)
196 			err = got_error_from_errno("read");
197 		else if (n != len_ids) {
198 			err = got_error(GOT_ERR_BAD_PACKIDX);
199 			goto done;
200 		}
201 	}
202 	if (verify)
203 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
204 	offset += len_ids;
205 	remain -= len_ids;
206 
207 	if (remain < nobj * sizeof(*h->crc32)) {
208 		err = got_error(GOT_ERR_BAD_PACKIDX);
209 		goto done;
210 	}
211 	if (p->map)
212 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
213 	else {
214 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
215 		if (h->crc32 == NULL) {
216 			err = got_error_from_errno("malloc");
217 			goto done;
218 		}
219 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
220 		if (n < 0)
221 			err = got_error_from_errno("read");
222 		else if (n != nobj * sizeof(*h->crc32)) {
223 			err = got_error(GOT_ERR_BAD_PACKIDX);
224 			goto done;
225 		}
226 	}
227 	if (verify)
228 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
229 	remain -= nobj * sizeof(*h->crc32);
230 	offset += nobj * sizeof(*h->crc32);
231 
232 	if (remain < nobj * sizeof(*h->offsets)) {
233 		err = got_error(GOT_ERR_BAD_PACKIDX);
234 		goto done;
235 	}
236 	if (p->map)
237 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
238 	else {
239 		h->offsets = malloc(nobj * sizeof(*h->offsets));
240 		if (h->offsets == NULL) {
241 			err = got_error_from_errno("malloc");
242 			goto done;
243 		}
244 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
245 		if (n < 0)
246 			err = got_error_from_errno("read");
247 		else if (n != nobj * sizeof(*h->offsets)) {
248 			err = got_error(GOT_ERR_BAD_PACKIDX);
249 			goto done;
250 		}
251 	}
252 	if (verify)
253 		SHA1Update(&ctx, (uint8_t *)h->offsets,
254 		    nobj * sizeof(*h->offsets));
255 	remain -= nobj * sizeof(*h->offsets);
256 	offset += nobj * sizeof(*h->offsets);
257 
258 	/* Large file offsets are contained only in files > 2GB. */
259 	for (i = 0; i < nobj; i++) {
260 		uint32_t o = betoh32(h->offsets[i]);
261 		if (o & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX)
262 			p->nlargeobj++;
263 	}
264 	if (p->nlargeobj == 0)
265 		goto checksum;
266 
267 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
268 		err = got_error(GOT_ERR_BAD_PACKIDX);
269 		goto done;
270 	}
271 	if (p->map)
272 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
273 	else {
274 		h->large_offsets = malloc(p->nlargeobj *
275 		    sizeof(*h->large_offsets));
276 		if (h->large_offsets == NULL) {
277 			err = got_error_from_errno("malloc");
278 			goto done;
279 		}
280 		n = read(p->fd, h->large_offsets,
281 		    p->nlargeobj * sizeof(*h->large_offsets));
282 		if (n < 0)
283 			err = got_error_from_errno("read");
284 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
285 			err = got_error(GOT_ERR_BAD_PACKIDX);
286 			goto done;
287 		}
288 	}
289 	if (verify)
290 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
291 		    p->nlargeobj * sizeof(*h->large_offsets));
292 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
293 	offset += p->nlargeobj * sizeof(*h->large_offsets);
294 
295 checksum:
296 	if (remain < sizeof(*h->trailer)) {
297 		err = got_error(GOT_ERR_BAD_PACKIDX);
298 		goto done;
299 	}
300 	if (p->map)
301 		h->trailer =
302 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
303 	else {
304 		h->trailer = malloc(sizeof(*h->trailer));
305 		if (h->trailer == NULL) {
306 			err = got_error_from_errno("malloc");
307 			goto done;
308 		}
309 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
310 		if (n < 0)
311 			err = got_error_from_errno("read");
312 		else if (n != sizeof(*h->trailer)) {
313 			err = got_error(GOT_ERR_BAD_PACKIDX);
314 			goto done;
315 		}
316 	}
317 	if (verify) {
318 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
319 		SHA1Final(sha1, &ctx);
320 		if (memcmp(h->trailer->packidx_sha1, sha1,
321 		    SHA1_DIGEST_LENGTH) != 0)
322 			err = got_error(GOT_ERR_PACKIDX_CSUM);
323 	}
324 done:
325 	return err;
326 }
327 
328 const struct got_error *
329 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
330 {
331 	const struct got_error *err = NULL;
332 	struct got_packidx *p;
333 	struct stat sb;
334 
335 	*packidx = NULL;
336 
337 	p = calloc(1, sizeof(*p));
338 	if (p == NULL)
339 		return got_error_from_errno("calloc");
340 
341 	p->fd = open(path, O_RDONLY | O_NOFOLLOW);
342 	if (p->fd == -1) {
343 		err = got_error_from_errno2("open", path);
344 		free(p);
345 		return err;
346 	}
347 
348 	if (fstat(p->fd, &sb) != 0) {
349 		err = got_error_from_errno2("fstat", path);
350 		close(p->fd);
351 		free(p);
352 		return err;
353 	}
354 	p->len = sb.st_size;
355 	if (p->len < sizeof(p->hdr)) {
356 		err = got_error(GOT_ERR_BAD_PACKIDX);
357 		close(p->fd);
358 		free(p);
359 		return err;
360 	}
361 
362 	p->path_packidx = strdup(path);
363 	if (p->path_packidx == NULL) {
364 		err = got_error_from_errno("strdup");
365 		goto done;
366 	}
367 
368 #ifndef GOT_PACK_NO_MMAP
369 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
370 	if (p->map == MAP_FAILED) {
371 		if (errno != ENOMEM) {
372 			err = got_error_from_errno("mmap");
373 			goto done;
374 		}
375 		p->map = NULL; /* fall back to read(2) */
376 	}
377 #endif
378 
379 	err = got_packidx_init_hdr(p, verify);
380 done:
381 	if (err)
382 		got_packidx_close(p);
383 	else
384 		*packidx = p;
385 
386 	return err;
387 }
388 
389 const struct got_error *
390 got_packidx_close(struct got_packidx *packidx)
391 {
392 	const struct got_error *err = NULL;
393 
394 	free(packidx->path_packidx);
395 	if (packidx->map) {
396 		if (munmap(packidx->map, packidx->len) == -1)
397 			err = got_error_from_errno("munmap");
398 	} else {
399 		free(packidx->hdr.magic);
400 		free(packidx->hdr.version);
401 		free(packidx->hdr.fanout_table);
402 		free(packidx->hdr.sorted_ids);
403 		free(packidx->hdr.crc32);
404 		free(packidx->hdr.offsets);
405 		free(packidx->hdr.large_offsets);
406 		free(packidx->hdr.trailer);
407 	}
408 	if (close(packidx->fd) != 0 && err == NULL)
409 		err = got_error_from_errno("close");
410 	free(packidx);
411 
412 	return err;
413 }
414 
415 static off_t
416 get_object_offset(struct got_packidx *packidx, int idx)
417 {
418 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
419 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
420 		uint64_t loffset;
421 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
422 		if (idx < 0 || idx >= packidx->nlargeobj ||
423 		    packidx->hdr.large_offsets == NULL)
424 			return -1;
425 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
426 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
427 	}
428 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
429 }
430 
431 int
432 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
433 {
434 	u_int8_t id0 = id->sha1[0];
435 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
436 	int left = 0, right = totobj - 1;
437 
438 	if (id0 > 0)
439 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
440 
441 	while (left <= right) {
442 		struct got_packidx_object_id *oid;
443 		int i, cmp;
444 
445 		i = ((left + right) / 2);
446 		oid = &packidx->hdr.sorted_ids[i];
447 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
448 		if (cmp == 0)
449 			return i;
450 		else if (cmp > 0)
451 			left = i + 1;
452 		else if (cmp < 0)
453 			right = i - 1;
454 	}
455 
456 	return -1;
457 }
458 
459 const struct got_error *
460 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
461     struct got_packidx *packidx, const char *id_str_prefix)
462 {
463 	const struct got_error *err = NULL;
464 	u_int8_t id0;
465 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
466 	char hex[3];
467 	size_t prefix_len = strlen(id_str_prefix);
468 	struct got_packidx_object_id *oid;
469 	int i;
470 
471 	SIMPLEQ_INIT(matched_ids);
472 
473 	if (prefix_len < 2)
474 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
475 
476 	hex[0] = id_str_prefix[0];
477 	hex[1] = id_str_prefix[1];
478 	hex[2] = '\0';
479 	if (!got_parse_xdigit(&id0, hex))
480 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
481 
482 	i = betoh32(packidx->hdr.fanout_table[id0 - 1]);
483 	if (i == 0)
484 		return NULL;
485 
486 	oid = &packidx->hdr.sorted_ids[i];
487 	while (i < totobj && oid->sha1[0] == id0) {
488 		char id_str[SHA1_DIGEST_STRING_LENGTH];
489 		struct got_object_qid *qid;
490 		int cmp;
491 
492 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
493 		        return got_error(GOT_ERR_NO_SPACE);
494 
495 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
496 		if (cmp < 0) {
497 			oid = &packidx->hdr.sorted_ids[++i];
498 			continue;
499 		} else if (cmp > 0)
500 			break;
501 
502 		err = got_object_qid_alloc_partial(&qid);
503 		if (err)
504 			break;
505 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
506 		SIMPLEQ_INSERT_TAIL(matched_ids, qid, entry);
507 
508 		oid = &packidx->hdr.sorted_ids[++i];
509 	}
510 
511 	if (err)
512 		got_object_id_queue_free(matched_ids);
513 	return err;
514 }
515 
516 const struct got_error *
517 got_pack_stop_privsep_child(struct got_pack *pack)
518 {
519 	const struct got_error *err = NULL;
520 
521 	if (pack->privsep_child == NULL)
522 		return NULL;
523 
524 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
525 	if (err)
526 		return err;
527 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
528 	if (close(pack->privsep_child->imsg_fd) != 0 && err == NULL)
529 		err = got_error_from_errno("close");
530 	free(pack->privsep_child);
531 	pack->privsep_child = NULL;
532 	return err;
533 }
534 
535 const struct got_error *
536 got_pack_close(struct got_pack *pack)
537 {
538 	const struct got_error *err = NULL;
539 
540 	err = got_pack_stop_privsep_child(pack);
541 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
542 		err = got_error_from_errno("munmap");
543 	if (pack->fd != -1 && close(pack->fd) != 0 && err == NULL)
544 		err = got_error_from_errno("close");
545 	pack->fd = -1;
546 	free(pack->path_packfile);
547 	pack->path_packfile = NULL;
548 	pack->filesize = 0;
549 
550 	return err;
551 }
552 
553 static const struct got_error *
554 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
555     struct got_pack *pack, off_t offset)
556 {
557 	uint8_t t = 0;
558 	uint64_t s = 0;
559 	uint8_t sizeN;
560 	size_t mapoff = 0;
561 	int i = 0;
562 
563 	*len = 0;
564 
565 	if (offset >= pack->filesize)
566 		return got_error(GOT_ERR_PACK_OFFSET);
567 
568 	if (pack->map) {
569 		mapoff = (size_t)offset;
570 	} else {
571 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
572 			return got_error_from_errno("lseek");
573 	}
574 
575 	do {
576 		/* We do not support size values which don't fit in 64 bit. */
577 		if (i > 9)
578 			return got_error(GOT_ERR_NO_SPACE);
579 
580 		if (pack->map) {
581 			sizeN = *(pack->map + mapoff);
582 			mapoff += sizeof(sizeN);
583 		} else {
584 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
585 			if (n < 0)
586 				return got_error_from_errno("read");
587 			if (n != sizeof(sizeN))
588 				return got_error(GOT_ERR_BAD_PACKFILE);
589 		}
590 		*len += sizeof(sizeN);
591 
592 		if (i == 0) {
593 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
594 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
595 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
596 		} else {
597 			size_t shift = 4 + 7 * (i - 1);
598 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
599 		}
600 		i++;
601 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
602 
603 	*type = t;
604 	*size = s;
605 	return NULL;
606 }
607 
608 static const struct got_error *
609 open_plain_object(struct got_object **obj, const char *path_packfile,
610     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
611 {
612 	*obj = calloc(1, sizeof(**obj));
613 	if (*obj == NULL)
614 		return got_error_from_errno("calloc");
615 
616 	(*obj)->path_packfile = strdup(path_packfile);
617 	if ((*obj)->path_packfile == NULL) {
618 		const struct got_error *err = got_error_from_errno("strdup");
619 		free(*obj);
620 		*obj = NULL;
621 		return err;
622 	}
623 
624 	(*obj)->type = type;
625 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
626 	(*obj)->pack_idx = idx;
627 	(*obj)->hdrlen = 0;
628 	(*obj)->size = size;
629 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
630 	(*obj)->pack_offset = offset;
631 
632 	return NULL;
633 }
634 
635 static const struct got_error *
636 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
637     off_t delta_offset)
638 {
639 	int64_t o = 0;
640 	uint8_t offN;
641 	int i = 0;
642 
643 	*offset = 0;
644 	*len = 0;
645 
646 	do {
647 		/* We do not support offset values which don't fit in 64 bit. */
648 		if (i > 8)
649 			return got_error(GOT_ERR_NO_SPACE);
650 
651 		if (pack->map) {
652 			size_t mapoff;
653 			if (delta_offset >= pack->filesize)
654 				return got_error(GOT_ERR_PACK_OFFSET);
655 			mapoff = (size_t)delta_offset + *len;
656 			offN = *(pack->map + mapoff);
657 		} else {
658 			ssize_t n;
659 			n = read(pack->fd, &offN, sizeof(offN));
660 			if (n < 0)
661 				return got_error_from_errno("read");
662 			if (n != sizeof(offN))
663 				return got_error(GOT_ERR_BAD_PACKFILE);
664 		}
665 		*len += sizeof(offN);
666 
667 		if (i == 0)
668 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
669 		else {
670 			o++;
671 			o <<= 7;
672 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
673 		}
674 		i++;
675 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
676 
677 	*offset = o;
678 	return NULL;
679 }
680 
681 static const struct got_error *
682 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
683     off_t offset, int tslen)
684 {
685 	const struct got_error *err;
686 	int64_t negoffset;
687 	size_t negofflen;
688 
689 	*len = 0;
690 
691 	err = parse_negative_offset(&negoffset, &negofflen, pack,
692 	    offset + tslen);
693 	if (err)
694 		return err;
695 
696 	/* Compute the base object's offset (must be in the same pack file). */
697 	*base_offset = (offset - negoffset);
698 	if (*base_offset <= 0)
699 		return got_error(GOT_ERR_BAD_PACKFILE);
700 
701 	*len = negofflen;
702 	return NULL;
703 }
704 
705 static const struct got_error *
706 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
707     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
708 
709 static const struct got_error *
710 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
711     int delta_type, size_t delta_size, size_t delta_data_offset,
712     uint8_t *delta_buf, size_t delta_len)
713 {
714 	struct got_delta *delta;
715 
716 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
717 	    delta_data_offset, delta_buf,
718 	    delta_len);
719 	if (delta == NULL)
720 		return got_error_from_errno("got_delta_open");
721 	/* delta is freed in got_object_close() */
722 	deltas->nentries++;
723 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
724 	return NULL;
725 }
726 
727 static const struct got_error *
728 resolve_offset_delta(struct got_delta_chain *deltas,
729     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
730     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
731 
732 {
733 	const struct got_error *err;
734 	off_t base_offset;
735 	uint8_t base_type;
736 	uint64_t base_size;
737 	size_t base_tslen;
738 	off_t delta_data_offset;
739 	uint8_t *delta_buf;
740 	size_t delta_len, consumed;
741 
742 	err = parse_offset_delta(&base_offset, &consumed, pack,
743 	    delta_offset, tslen);
744 	if (err)
745 		return err;
746 
747 	delta_data_offset = delta_offset + tslen + consumed;
748 	if (delta_data_offset >= pack->filesize)
749 		return got_error(GOT_ERR_PACK_OFFSET);
750 
751 	if (pack->map == NULL) {
752 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
753 		if (delta_data_offset == -1)
754 			return got_error_from_errno("lseek");
755 	}
756 
757 	if (pack->map) {
758 		size_t mapoff = (size_t)delta_data_offset;
759 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
760 		    mapoff, pack->filesize - mapoff);
761 		if (err)
762 			return err;
763 	} else {
764 
765 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
766 		if (err)
767 			return err;
768 	}
769 
770 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
771 	    delta_data_offset, delta_buf, delta_len);
772 	if (err)
773 		return err;
774 
775 	/* An offset delta must be in the same packfile. */
776 	if (base_offset >= pack->filesize)
777 		return got_error(GOT_ERR_PACK_OFFSET);
778 
779 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
780 	    pack, base_offset);
781 	if (err)
782 		return err;
783 
784 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
785 	    base_tslen, base_type, base_size, recursion - 1);
786 }
787 
788 static const struct got_error *
789 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
790     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
791     size_t delta_size, unsigned int recursion)
792 {
793 	const struct got_error *err;
794 	struct got_object_id id;
795 	int idx;
796 	off_t base_offset;
797 	uint8_t base_type;
798 	uint64_t base_size;
799 	size_t base_tslen;
800 	off_t delta_data_offset;
801 	uint8_t *delta_buf;
802 	size_t delta_len;
803 
804 	if (delta_offset >= pack->filesize)
805 		return got_error(GOT_ERR_PACK_OFFSET);
806 	delta_data_offset = delta_offset + tslen;
807 	if (delta_data_offset >= pack->filesize)
808 		return got_error(GOT_ERR_PACK_OFFSET);
809 
810 	if (pack->map == NULL) {
811 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
812 		if (delta_data_offset == -1)
813 			return got_error_from_errno("lseek");
814 	}
815 
816 	if (pack->map) {
817 		size_t mapoff = (size_t)delta_data_offset;
818 		memcpy(&id, pack->map + mapoff, sizeof(id));
819 		mapoff += sizeof(id);
820 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
821 		    mapoff, pack->filesize - mapoff);
822 		if (err)
823 			return err;
824 	} else {
825 		ssize_t n = read(pack->fd, &id, sizeof(id));
826 		if (n < 0)
827 			return got_error_from_errno("read");
828 		if (n != sizeof(id))
829 			return got_error(GOT_ERR_BAD_PACKFILE);
830 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
831 		if (err)
832 			return err;
833 	}
834 
835 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
836 	    delta_data_offset, delta_buf, delta_len);
837 	if (err)
838 		return err;
839 
840 	/* Delta base must be in the same pack file. */
841 	idx = got_packidx_get_object_idx(packidx, &id);
842 	if (idx == -1)
843 		return got_error(GOT_ERR_BAD_PACKFILE);
844 
845 	base_offset = get_object_offset(packidx, idx);
846 	if (base_offset == (uint64_t)-1)
847 		return got_error(GOT_ERR_BAD_PACKIDX);
848 
849 	if (base_offset >= pack->filesize)
850 		return got_error(GOT_ERR_PACK_OFFSET);
851 
852 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
853 	    pack, base_offset);
854 	if (err)
855 		return err;
856 
857 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
858 	    base_tslen, base_type, base_size, recursion - 1);
859 }
860 
861 static const struct got_error *
862 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
863     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
864     size_t delta_size, unsigned int recursion)
865 {
866 	const struct got_error *err = NULL;
867 
868 	if (--recursion == 0)
869 		return got_error(GOT_ERR_RECURSION);
870 
871 	switch (delta_type) {
872 	case GOT_OBJ_TYPE_COMMIT:
873 	case GOT_OBJ_TYPE_TREE:
874 	case GOT_OBJ_TYPE_BLOB:
875 	case GOT_OBJ_TYPE_TAG:
876 		/* Plain types are the final delta base. Recursion ends. */
877 		err = add_delta(deltas, delta_offset, tslen, delta_type,
878 		    delta_size, 0, NULL, 0);
879 		break;
880 	case GOT_OBJ_TYPE_OFFSET_DELTA:
881 		err = resolve_offset_delta(deltas, packidx, pack,
882 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
883 		break;
884 	case GOT_OBJ_TYPE_REF_DELTA:
885 		err = resolve_ref_delta(deltas, packidx, pack,
886 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
887 		break;
888 	default:
889 		return got_error(GOT_ERR_OBJ_TYPE);
890 	}
891 
892 	return err;
893 }
894 
895 static const struct got_error *
896 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
897     struct got_pack *pack, struct got_object_id *id, off_t offset,
898     size_t tslen, int delta_type, size_t delta_size, int idx)
899 {
900 	const struct got_error *err = NULL;
901 	int resolved_type;
902 
903 	*obj = calloc(1, sizeof(**obj));
904 	if (*obj == NULL)
905 		return got_error_from_errno("calloc");
906 
907 	(*obj)->flags = 0;
908 	(*obj)->hdrlen = 0;
909 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
910 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
911 	(*obj)->pack_offset = offset + tslen;
912 
913 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
914 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
915 
916 	(*obj)->path_packfile = strdup(pack->path_packfile);
917 	if ((*obj)->path_packfile == NULL) {
918 		err = got_error_from_errno("strdup");
919 		goto done;
920 	}
921 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
922 	(*obj)->pack_idx = idx;
923 
924 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
925 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
926 	if (err)
927 		goto done;
928 
929 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
930 	if (err)
931 		goto done;
932 	(*obj)->type = resolved_type;
933 done:
934 	if (err) {
935 		got_object_close(*obj);
936 		*obj = NULL;
937 	}
938 	return err;
939 }
940 
941 const struct got_error *
942 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
943     struct got_packidx *packidx, int idx, struct got_object_id *id)
944 {
945 	const struct got_error *err = NULL;
946 	off_t offset;
947 	uint8_t type;
948 	uint64_t size;
949 	size_t tslen;
950 
951 	*obj = NULL;
952 
953 	offset = get_object_offset(packidx, idx);
954 	if (offset == (uint64_t)-1)
955 		return got_error(GOT_ERR_BAD_PACKIDX);
956 
957 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
958 	if (err)
959 		return err;
960 
961 	switch (type) {
962 	case GOT_OBJ_TYPE_COMMIT:
963 	case GOT_OBJ_TYPE_TREE:
964 	case GOT_OBJ_TYPE_BLOB:
965 	case GOT_OBJ_TYPE_TAG:
966 		err = open_plain_object(obj, pack->path_packfile, id, type,
967 		    offset + tslen, size, idx);
968 		break;
969 	case GOT_OBJ_TYPE_OFFSET_DELTA:
970 	case GOT_OBJ_TYPE_REF_DELTA:
971 		err = open_delta_object(obj, packidx, pack, id, offset,
972 		    tslen, type, size, idx);
973 		break;
974 	default:
975 		err = got_error(GOT_ERR_OBJ_TYPE);
976 		break;
977 	}
978 
979 	return err;
980 }
981 
982 static const struct got_error *
983 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
984 {
985 	struct got_delta *delta;
986 	uint64_t base_size = 0, result_size = 0;
987 
988 	*max_size = 0;
989 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
990 		/* Plain object types are the delta base. */
991 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
992 		    delta->type != GOT_OBJ_TYPE_TREE &&
993 		    delta->type != GOT_OBJ_TYPE_BLOB &&
994 		    delta->type != GOT_OBJ_TYPE_TAG) {
995 			const struct got_error *err;
996 			err = got_delta_get_sizes(&base_size, &result_size,
997 			    delta->delta_buf, delta->delta_len);
998 			if (err)
999 				return err;
1000 		} else
1001 			base_size = delta->size;
1002 		if (base_size > *max_size)
1003 			*max_size = base_size;
1004 		if (result_size > *max_size)
1005 			*max_size = result_size;
1006 	}
1007 
1008 	return NULL;
1009 }
1010 
1011 const struct got_error *
1012 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj)
1013 {
1014 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1015 		return got_error(GOT_ERR_OBJ_TYPE);
1016 
1017 	return get_delta_chain_max_size(size, &obj->deltas);
1018 }
1019 
1020 static const struct got_error *
1021 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1022     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
1023 {
1024 	const struct got_error *err = NULL;
1025 	struct got_delta *delta;
1026 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1027 	size_t base_bufsz = 0, accum_size = 0;
1028 	uint64_t max_size;
1029 	int n = 0;
1030 
1031 	*result_size = 0;
1032 
1033 	if (SIMPLEQ_EMPTY(&deltas->entries))
1034 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1035 
1036 	/* We process small enough files entirely in memory for speed. */
1037 	err = get_delta_chain_max_size(&max_size, deltas);
1038 	if (err)
1039 		return err;
1040 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1041 		accum_buf = malloc(max_size);
1042 		if (accum_buf == NULL)
1043 			return got_error_from_errno("malloc");
1044 		base_file = NULL;
1045 		accum_file = NULL;
1046 	}
1047 
1048 	/* Deltas are ordered in ascending order. */
1049 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1050 		if (n == 0) {
1051 			size_t mapoff;
1052 			off_t delta_data_offset;
1053 
1054 			/* Plain object types are the delta base. */
1055 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1056 			    delta->type != GOT_OBJ_TYPE_TREE &&
1057 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1058 			    delta->type != GOT_OBJ_TYPE_TAG) {
1059 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1060 				goto done;
1061 			}
1062 
1063 			delta_data_offset = delta->offset + delta->tslen;
1064 			if (delta_data_offset >= pack->filesize) {
1065 				err = got_error(GOT_ERR_PACK_OFFSET);
1066 				goto done;
1067 			}
1068 			if (pack->map == NULL) {
1069 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1070 				    == -1) {
1071 					err = got_error_from_errno("lseek");
1072 					goto done;
1073 				}
1074 			}
1075 			if (base_file) {
1076 				if (pack->map) {
1077 					mapoff = (size_t)delta_data_offset;
1078 					err = got_inflate_to_file_mmap(
1079 					    &base_bufsz, pack->map, mapoff,
1080 					    pack->filesize - mapoff, base_file);
1081 				} else
1082 					err = got_inflate_to_file_fd(
1083 					    &base_bufsz, pack->fd, base_file);
1084 			} else {
1085 				if (pack->map) {
1086 					mapoff = (size_t)delta_data_offset;
1087 					err = got_inflate_to_mem_mmap(&base_buf,
1088 					    &base_bufsz, pack->map, mapoff,
1089 					    pack->filesize - mapoff);
1090 				} else
1091 					err = got_inflate_to_mem_fd(&base_buf,
1092 					    &base_bufsz, pack->fd);
1093 			}
1094 			if (err)
1095 				goto done;
1096 			n++;
1097 			if (base_file)
1098 				rewind(base_file);
1099 			continue;
1100 		}
1101 
1102 		if (base_buf) {
1103 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1104 			    delta->delta_buf, delta->delta_len, accum_buf,
1105 			    &accum_size, max_size);
1106 			n++;
1107 		} else {
1108 			err = got_delta_apply(base_file, delta->delta_buf,
1109 			    delta->delta_len,
1110 			    /* Final delta application writes to output file. */
1111 			    ++n < deltas->nentries ? accum_file : outfile,
1112 			    &accum_size);
1113 		}
1114 		if (err)
1115 			goto done;
1116 
1117 		if (n < deltas->nentries) {
1118 			/* Accumulated delta becomes the new base. */
1119 			if (base_buf) {
1120 				uint8_t *tmp = accum_buf;
1121 				/*
1122 				 * Base buffer switches roles with accumulation
1123 				 * buffer. Ensure it can hold the largest
1124 				 * result in the delta chain. The initial
1125 				 * allocation might have been smaller.
1126 				 */
1127 				if (base_bufsz < max_size) {
1128 					uint8_t *p;
1129 					p = reallocarray(base_buf, 1, max_size);
1130 					if (p == NULL) {
1131 						err = got_error_from_errno(
1132 						    "reallocarray");
1133 						goto done;
1134 					}
1135 					base_buf = p;
1136 					base_bufsz = max_size;
1137 				}
1138 				accum_buf = base_buf;
1139 				base_buf = tmp;
1140 			} else {
1141 				FILE *tmp = accum_file;
1142 				accum_file = base_file;
1143 				base_file = tmp;
1144 				rewind(base_file);
1145 				rewind(accum_file);
1146 			}
1147 		}
1148 	}
1149 
1150 done:
1151 	free(base_buf);
1152 	if (accum_buf) {
1153 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1154 		free(accum_buf);
1155 		if (len != accum_size)
1156 			err = got_ferror(outfile, GOT_ERR_IO);
1157 	}
1158 	rewind(outfile);
1159 	if (err == NULL)
1160 		*result_size = accum_size;
1161 	return err;
1162 }
1163 
1164 static const struct got_error *
1165 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1166     struct got_delta_chain *deltas, struct got_pack *pack)
1167 {
1168 	const struct got_error *err = NULL;
1169 	struct got_delta *delta;
1170 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1171 	size_t base_bufsz = 0, accum_size = 0;
1172 	uint64_t max_size;
1173 	int n = 0;
1174 
1175 	*outbuf = NULL;
1176 	*outlen = 0;
1177 
1178 	if (SIMPLEQ_EMPTY(&deltas->entries))
1179 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1180 
1181 	err = get_delta_chain_max_size(&max_size, deltas);
1182 	if (err)
1183 		return err;
1184 	accum_buf = malloc(max_size);
1185 	if (accum_buf == NULL)
1186 		return got_error_from_errno("malloc");
1187 
1188 	/* Deltas are ordered in ascending order. */
1189 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1190 		if (n == 0) {
1191 			size_t delta_data_offset;
1192 
1193 			/* Plain object types are the delta base. */
1194 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1195 			    delta->type != GOT_OBJ_TYPE_TREE &&
1196 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1197 			    delta->type != GOT_OBJ_TYPE_TAG) {
1198 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1199 				goto done;
1200 			}
1201 
1202 			delta_data_offset = delta->offset + delta->tslen;
1203 			if (delta_data_offset >= pack->filesize) {
1204 				err = got_error(GOT_ERR_PACK_OFFSET);
1205 				goto done;
1206 			}
1207 			if (pack->map) {
1208 				size_t mapoff = (size_t)delta_data_offset;
1209 				err = got_inflate_to_mem_mmap(&base_buf,
1210 				    &base_bufsz, pack->map, mapoff,
1211 				    pack->filesize - mapoff);
1212 			} else {
1213 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1214 				    == -1) {
1215 					err = got_error_from_errno("lseek");
1216 					goto done;
1217 				}
1218 				err = got_inflate_to_mem_fd(&base_buf,
1219 				    &base_bufsz, pack->fd);
1220 			}
1221 			if (err)
1222 				goto done;
1223 			n++;
1224 			continue;
1225 		}
1226 
1227 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1228 		    delta->delta_buf, delta->delta_len, accum_buf,
1229 		    &accum_size, max_size);
1230 		n++;
1231 		if (err)
1232 			goto done;
1233 
1234 		if (n < deltas->nentries) {
1235 			/* Accumulated delta becomes the new base. */
1236 			uint8_t *tmp = accum_buf;
1237 			/*
1238 			 * Base buffer switches roles with accumulation buffer.
1239 			 * Ensure it can hold the largest result in the delta
1240 			 * chain. Initial allocation might have been smaller.
1241 			 */
1242 			if (base_bufsz < max_size) {
1243 				uint8_t *p;
1244 				p = reallocarray(base_buf, 1, max_size);
1245 				if (p == NULL) {
1246 					err = got_error_from_errno(
1247 					    "reallocarray");
1248 					goto done;
1249 				}
1250 				base_buf = p;
1251 				base_bufsz = max_size;
1252 			}
1253 			accum_buf = base_buf;
1254 			base_buf = tmp;
1255 		}
1256 	}
1257 
1258 done:
1259 	free(base_buf);
1260 	if (err) {
1261 		free(accum_buf);
1262 		*outbuf = NULL;
1263 		*outlen = 0;
1264 	} else {
1265 		*outbuf = accum_buf;
1266 		*outlen = accum_size;
1267 	}
1268 	return err;
1269 }
1270 
1271 const struct got_error *
1272 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1273     FILE *outfile, FILE *base_file, FILE *accum_file)
1274 {
1275 	const struct got_error *err = NULL;
1276 
1277 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1278 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1279 
1280 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1281 		if (obj->pack_offset >= pack->filesize)
1282 			return got_error(GOT_ERR_PACK_OFFSET);
1283 
1284 		if (pack->map) {
1285 			size_t mapoff = (size_t)obj->pack_offset;
1286 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1287 			    mapoff, pack->filesize - mapoff, outfile);
1288 		} else {
1289 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1290 				return got_error_from_errno("lseek");
1291 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1292 			    outfile);
1293 		}
1294 	} else
1295 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1296 		    outfile, base_file, accum_file);
1297 
1298 	return err;
1299 }
1300 
1301 const struct got_error *
1302 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1303     struct got_object *obj, struct got_pack *pack)
1304 {
1305 	const struct got_error *err = NULL;
1306 
1307 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1308 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1309 
1310 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1311 		if (obj->pack_offset >= pack->filesize)
1312 			return got_error(GOT_ERR_PACK_OFFSET);
1313 		if (pack->map) {
1314 			size_t mapoff = (size_t)obj->pack_offset;
1315 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1316 			    mapoff, pack->filesize - mapoff);
1317 		} else {
1318 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1319 				return got_error_from_errno("lseek");
1320 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1321 		}
1322 	} else
1323 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1324 
1325 	return err;
1326 }