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Date:: Fri Oct 11 09:10:54 2019 UTC
Message:: properly handle read errors in got_packidx_init_hdr (found by jj@ scan-build)
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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 			goto done;
101 		} else if (n != sizeof(*h->magic)) {
102 			err = got_error(GOT_ERR_BAD_PACKIDX);
103 			goto done;
104 		}
105 	}
106 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
107 		err = got_error(GOT_ERR_BAD_PACKIDX);
108 		goto done;
109 	}
110 	offset += sizeof(*h->magic);
111 	remain -= sizeof(*h->magic);
112 
113 	if (verify)
114 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
115 
116 	if (remain < sizeof(*h->version)) {
117 		err = got_error(GOT_ERR_BAD_PACKIDX);
118 		goto done;
119 	}
120 	if (p->map)
121 		h->version = (uint32_t *)(p->map + offset);
122 	else {
123 		h->version = malloc(sizeof(*h->version));
124 		if (h->version == NULL) {
125 			err = got_error_from_errno("malloc");
126 			goto done;
127 		}
128 		n = read(p->fd, h->version, sizeof(*h->version));
129 		if (n < 0) {
130 			err = got_error_from_errno("read");
131 			goto done;
132 		} else if (n != sizeof(*h->version)) {
133 			err = got_error(GOT_ERR_BAD_PACKIDX);
134 			goto done;
135 		}
136 	}
137 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
138 		err = got_error(GOT_ERR_BAD_PACKIDX);
139 		goto done;
140 	}
141 	offset += sizeof(*h->version);
142 	remain -= sizeof(*h->version);
143 
144 	if (verify)
145 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
146 
147 	len_fanout =
148 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
149 	if (remain < len_fanout) {
150 		err = got_error(GOT_ERR_BAD_PACKIDX);
151 		goto done;
152 	}
153 	if (p->map)
154 		h->fanout_table = (uint32_t *)(p->map + offset);
155 	else {
156 		h->fanout_table = malloc(len_fanout);
157 		if (h->fanout_table == NULL) {
158 			err = got_error_from_errno("malloc");
159 			goto done;
160 		}
161 		n = read(p->fd, h->fanout_table, len_fanout);
162 		if (n < 0) {
163 			err = got_error_from_errno("read");
164 			goto done;
165 		} else if (n != len_fanout) {
166 			err = got_error(GOT_ERR_BAD_PACKIDX);
167 			goto done;
168 		}
169 	}
170 	err = verify_fanout_table(h->fanout_table);
171 	if (err)
172 		goto done;
173 	if (verify)
174 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
175 	offset += len_fanout;
176 	remain -= len_fanout;
177 
178 	nobj = betoh32(h->fanout_table[0xff]);
179 	len_ids = nobj * sizeof(*h->sorted_ids);
180 	if (len_ids <= nobj || len_ids > remain) {
181 		err = got_error(GOT_ERR_BAD_PACKIDX);
182 		goto done;
183 	}
184 	if (p->map)
185 		h->sorted_ids =
186 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
187 	else {
188 		h->sorted_ids = malloc(len_ids);
189 		if (h->sorted_ids == NULL) {
190 			err = got_error(GOT_ERR_BAD_PACKIDX);
191 			goto done;
192 		}
193 		n = read(p->fd, h->sorted_ids, len_ids);
194 		if (n < 0)
195 			err = got_error_from_errno("read");
196 		else if (n != len_ids) {
197 			err = got_error(GOT_ERR_BAD_PACKIDX);
198 			goto done;
199 		}
200 	}
201 	if (verify)
202 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
203 	offset += len_ids;
204 	remain -= len_ids;
205 
206 	if (remain < nobj * sizeof(*h->crc32)) {
207 		err = got_error(GOT_ERR_BAD_PACKIDX);
208 		goto done;
209 	}
210 	if (p->map)
211 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
212 	else {
213 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
214 		if (h->crc32 == NULL) {
215 			err = got_error_from_errno("malloc");
216 			goto done;
217 		}
218 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
219 		if (n < 0)
220 			err = got_error_from_errno("read");
221 		else if (n != nobj * sizeof(*h->crc32)) {
222 			err = got_error(GOT_ERR_BAD_PACKIDX);
223 			goto done;
224 		}
225 	}
226 	if (verify)
227 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
228 	remain -= nobj * sizeof(*h->crc32);
229 	offset += nobj * sizeof(*h->crc32);
230 
231 	if (remain < nobj * sizeof(*h->offsets)) {
232 		err = got_error(GOT_ERR_BAD_PACKIDX);
233 		goto done;
234 	}
235 	if (p->map)
236 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
237 	else {
238 		h->offsets = malloc(nobj * sizeof(*h->offsets));
239 		if (h->offsets == NULL) {
240 			err = got_error_from_errno("malloc");
241 			goto done;
242 		}
243 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
244 		if (n < 0)
245 			err = got_error_from_errno("read");
246 		else if (n != nobj * sizeof(*h->offsets)) {
247 			err = got_error(GOT_ERR_BAD_PACKIDX);
248 			goto done;
249 		}
250 	}
251 	if (verify)
252 		SHA1Update(&ctx, (uint8_t *)h->offsets,
253 		    nobj * sizeof(*h->offsets));
254 	remain -= nobj * sizeof(*h->offsets);
255 	offset += nobj * sizeof(*h->offsets);
256 
257 	/* Large file offsets are contained only in files > 2GB. */
258 	if (p->len <= 0x80000000)
259 		goto checksum;
260 
261 	if (remain < nobj * sizeof(*h->large_offsets)) {
262 		err = got_error(GOT_ERR_BAD_PACKIDX);
263 		goto done;
264 	}
265 	if (p->map)
266 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
267 	else {
268 		h->large_offsets = malloc(nobj * sizeof(*h->large_offsets));
269 		if (h->large_offsets == NULL) {
270 			err = got_error_from_errno("malloc");
271 			goto done;
272 		}
273 		n = read(p->fd, h->large_offsets,
274 		    nobj * sizeof(*h->large_offsets));
275 		if (n < 0)
276 			err = got_error_from_errno("read");
277 		else if (n != nobj * sizeof(*h->large_offsets)) {
278 			err = got_error(GOT_ERR_BAD_PACKIDX);
279 			goto done;
280 		}
281 	}
282 	if (verify)
283 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
284 		    nobj * sizeof(*h->large_offsets));
285 	remain -= nobj * sizeof(*h->large_offsets);
286 	offset += nobj * sizeof(*h->large_offsets);
287 
288 checksum:
289 	if (remain < sizeof(*h->trailer)) {
290 		err = got_error(GOT_ERR_BAD_PACKIDX);
291 		goto done;
292 	}
293 	if (p->map)
294 		h->trailer =
295 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
296 	else {
297 		h->trailer = malloc(sizeof(*h->trailer));
298 		if (h->trailer == NULL) {
299 			err = got_error_from_errno("malloc");
300 			goto done;
301 		}
302 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
303 		if (n < 0)
304 			err = got_error_from_errno("read");
305 		else if (n != sizeof(*h->trailer)) {
306 			err = got_error(GOT_ERR_BAD_PACKIDX);
307 			goto done;
308 		}
309 	}
310 	if (verify) {
311 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
312 		SHA1Final(sha1, &ctx);
313 		if (memcmp(h->trailer->packidx_sha1, sha1,
314 		    SHA1_DIGEST_LENGTH) != 0)
315 			err = got_error(GOT_ERR_PACKIDX_CSUM);
316 	}
317 done:
318 	return err;
319 }
320 
321 const struct got_error *
322 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
323 {
324 	const struct got_error *err = NULL;
325 	struct got_packidx *p;
326 	struct stat sb;
327 
328 	*packidx = NULL;
329 
330 	p = calloc(1, sizeof(*p));
331 	if (p == NULL)
332 		return got_error_from_errno("calloc");
333 
334 	p->fd = open(path, O_RDONLY | O_NOFOLLOW);
335 	if (p->fd == -1) {
336 		err = got_error_from_errno2("open", path);
337 		free(p);
338 		return err;
339 	}
340 
341 	if (fstat(p->fd, &sb) != 0) {
342 		err = got_error_from_errno2("fstat", path);
343 		close(p->fd);
344 		free(p);
345 		return err;
346 	}
347 	p->len = sb.st_size;
348 	if (p->len < sizeof(p->hdr)) {
349 		err = got_error(GOT_ERR_BAD_PACKIDX);
350 		close(p->fd);
351 		free(p);
352 		return err;
353 	}
354 
355 	p->path_packidx = strdup(path);
356 	if (p->path_packidx == NULL) {
357 		err = got_error_from_errno("strdup");
358 		goto done;
359 	}
360 
361 #ifndef GOT_PACK_NO_MMAP
362 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
363 	if (p->map == MAP_FAILED) {
364 		if (errno != ENOMEM) {
365 			err = got_error_from_errno("mmap");
366 			goto done;
367 		}
368 		p->map = NULL; /* fall back to read(2) */
369 	}
370 #endif
371 
372 	err = got_packidx_init_hdr(p, verify);
373 done:
374 	if (err)
375 		got_packidx_close(p);
376 	else
377 		*packidx = p;
378 
379 	return err;
380 }
381 
382 const struct got_error *
383 got_packidx_close(struct got_packidx *packidx)
384 {
385 	const struct got_error *err = NULL;
386 
387 	free(packidx->path_packidx);
388 	if (packidx->map) {
389 		if (munmap(packidx->map, packidx->len) == -1)
390 			err = got_error_from_errno("munmap");
391 	} else {
392 		free(packidx->hdr.magic);
393 		free(packidx->hdr.version);
394 		free(packidx->hdr.fanout_table);
395 		free(packidx->hdr.sorted_ids);
396 		free(packidx->hdr.crc32);
397 		free(packidx->hdr.offsets);
398 		free(packidx->hdr.large_offsets);
399 		free(packidx->hdr.trailer);
400 	}
401 	if (close(packidx->fd) != 0 && err == NULL)
402 		err = got_error_from_errno("close");
403 	free(packidx);
404 
405 	return err;
406 }
407 
408 static off_t
409 get_object_offset(struct got_packidx *packidx, int idx)
410 {
411 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
412 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
413 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
414 		uint64_t loffset;
415 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
416 		if (idx < 0 || idx > totobj ||
417 		    packidx->hdr.large_offsets == NULL)
418 			return -1;
419 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
420 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
421 	}
422 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
423 }
424 
425 int
426 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
427 {
428 	u_int8_t id0 = id->sha1[0];
429 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
430 	int left = 0, right = totobj - 1;
431 
432 	if (id0 > 0)
433 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
434 
435 	while (left <= right) {
436 		struct got_packidx_object_id *oid;
437 		int i, cmp;
438 
439 		i = ((left + right) / 2);
440 		oid = &packidx->hdr.sorted_ids[i];
441 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
442 		if (cmp == 0)
443 			return i;
444 		else if (cmp > 0)
445 			left = i + 1;
446 		else if (cmp < 0)
447 			right = i - 1;
448 	}
449 
450 	return -1;
451 }
452 
453 const struct got_error *
454 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
455     struct got_packidx *packidx, const char *id_str_prefix)
456 {
457 	const struct got_error *err = NULL;
458 	u_int8_t id0;
459 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
460 	char hex[3];
461 	size_t prefix_len = strlen(id_str_prefix);
462 	struct got_packidx_object_id *oid;
463 	int i;
464 
465 	SIMPLEQ_INIT(matched_ids);
466 
467 	if (prefix_len < 2)
468 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
469 
470 	hex[0] = id_str_prefix[0];
471 	hex[1] = id_str_prefix[1];
472 	hex[2] = '\0';
473 	if (!got_parse_xdigit(&id0, hex))
474 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
475 
476 	i = betoh32(packidx->hdr.fanout_table[id0 - 1]);
477 	if (i == 0)
478 		return NULL;
479 
480 	oid = &packidx->hdr.sorted_ids[i];
481 	while (i < totobj && oid->sha1[0] == id0) {
482 		char id_str[SHA1_DIGEST_STRING_LENGTH];
483 		struct got_object_qid *qid;
484 		int cmp;
485 
486 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
487 		        return got_error(GOT_ERR_NO_SPACE);
488 
489 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
490 		if (cmp < 0) {
491 			oid = &packidx->hdr.sorted_ids[++i];
492 			continue;
493 		} else if (cmp > 0)
494 			break;
495 
496 		err = got_object_qid_alloc_partial(&qid);
497 		if (err)
498 			break;
499 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
500 		SIMPLEQ_INSERT_TAIL(matched_ids, qid, entry);
501 
502 		oid = &packidx->hdr.sorted_ids[++i];
503 	}
504 
505 	if (err)
506 		got_object_id_queue_free(matched_ids);
507 	return err;
508 }
509 
510 const struct got_error *
511 got_pack_stop_privsep_child(struct got_pack *pack)
512 {
513 	const struct got_error *err = NULL;
514 
515 	if (pack->privsep_child == NULL)
516 		return NULL;
517 
518 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
519 	if (err)
520 		return err;
521 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
522 	if (close(pack->privsep_child->imsg_fd) != 0 && err == NULL)
523 		err = got_error_from_errno("close");
524 	free(pack->privsep_child);
525 	pack->privsep_child = NULL;
526 	return err;
527 }
528 
529 const struct got_error *
530 got_pack_close(struct got_pack *pack)
531 {
532 	const struct got_error *err = NULL;
533 
534 	err = got_pack_stop_privsep_child(pack);
535 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
536 		err = got_error_from_errno("munmap");
537 	if (pack->fd != -1 && close(pack->fd) != 0 && err == NULL)
538 		err = got_error_from_errno("close");
539 	pack->fd = -1;
540 	free(pack->path_packfile);
541 	pack->path_packfile = NULL;
542 	pack->filesize = 0;
543 
544 	return err;
545 }
546 
547 static const struct got_error *
548 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
549     struct got_pack *pack, off_t offset)
550 {
551 	uint8_t t = 0;
552 	uint64_t s = 0;
553 	uint8_t sizeN;
554 	size_t mapoff = 0;
555 	int i = 0;
556 
557 	*len = 0;
558 
559 	if (offset >= pack->filesize)
560 		return got_error(GOT_ERR_PACK_OFFSET);
561 
562 	if (pack->map) {
563 		mapoff = (size_t)offset;
564 	} else {
565 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
566 			return got_error_from_errno("lseek");
567 	}
568 
569 	do {
570 		/* We do not support size values which don't fit in 64 bit. */
571 		if (i > 9)
572 			return got_error(GOT_ERR_NO_SPACE);
573 
574 		if (pack->map) {
575 			sizeN = *(pack->map + mapoff);
576 			mapoff += sizeof(sizeN);
577 		} else {
578 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
579 			if (n < 0)
580 				return got_error_from_errno("read");
581 			if (n != sizeof(sizeN))
582 				return got_error(GOT_ERR_BAD_PACKFILE);
583 		}
584 		*len += sizeof(sizeN);
585 
586 		if (i == 0) {
587 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
588 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
589 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
590 		} else {
591 			size_t shift = 4 + 7 * (i - 1);
592 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
593 		}
594 		i++;
595 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
596 
597 	*type = t;
598 	*size = s;
599 	return NULL;
600 }
601 
602 static const struct got_error *
603 open_plain_object(struct got_object **obj, const char *path_packfile,
604     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
605 {
606 	*obj = calloc(1, sizeof(**obj));
607 	if (*obj == NULL)
608 		return got_error_from_errno("calloc");
609 
610 	(*obj)->path_packfile = strdup(path_packfile);
611 	if ((*obj)->path_packfile == NULL) {
612 		const struct got_error *err = got_error_from_errno("strdup");
613 		free(*obj);
614 		*obj = NULL;
615 		return err;
616 	}
617 
618 	(*obj)->type = type;
619 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
620 	(*obj)->pack_idx = idx;
621 	(*obj)->hdrlen = 0;
622 	(*obj)->size = size;
623 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
624 	(*obj)->pack_offset = offset;
625 
626 	return NULL;
627 }
628 
629 static const struct got_error *
630 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
631     off_t delta_offset)
632 {
633 	int64_t o = 0;
634 	uint8_t offN;
635 	int i = 0;
636 
637 	*offset = 0;
638 	*len = 0;
639 
640 	do {
641 		/* We do not support offset values which don't fit in 64 bit. */
642 		if (i > 8)
643 			return got_error(GOT_ERR_NO_SPACE);
644 
645 		if (pack->map) {
646 			size_t mapoff;
647 			if (delta_offset >= pack->filesize)
648 				return got_error(GOT_ERR_PACK_OFFSET);
649 			mapoff = (size_t)delta_offset + *len;
650 			offN = *(pack->map + mapoff);
651 		} else {
652 			ssize_t n;
653 			n = read(pack->fd, &offN, sizeof(offN));
654 			if (n < 0)
655 				return got_error_from_errno("read");
656 			if (n != sizeof(offN))
657 				return got_error(GOT_ERR_BAD_PACKFILE);
658 		}
659 		*len += sizeof(offN);
660 
661 		if (i == 0)
662 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
663 		else {
664 			o++;
665 			o <<= 7;
666 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
667 		}
668 		i++;
669 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
670 
671 	*offset = o;
672 	return NULL;
673 }
674 
675 static const struct got_error *
676 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
677     off_t offset, int tslen)
678 {
679 	const struct got_error *err;
680 	int64_t negoffset;
681 	size_t negofflen;
682 
683 	*len = 0;
684 
685 	err = parse_negative_offset(&negoffset, &negofflen, pack,
686 	    offset + tslen);
687 	if (err)
688 		return err;
689 
690 	/* Compute the base object's offset (must be in the same pack file). */
691 	*base_offset = (offset - negoffset);
692 	if (*base_offset <= 0)
693 		return got_error(GOT_ERR_BAD_PACKFILE);
694 
695 	*len = negofflen;
696 	return NULL;
697 }
698 
699 static const struct got_error *
700 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
701     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
702 
703 static const struct got_error *
704 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
705     int delta_type, size_t delta_size, size_t delta_data_offset,
706     uint8_t *delta_buf, size_t delta_len)
707 {
708 	struct got_delta *delta;
709 
710 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
711 	    delta_data_offset, delta_buf,
712 	    delta_len);
713 	if (delta == NULL)
714 		return got_error_from_errno("got_delta_open");
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_packidx *packidx, struct got_pack *pack, off_t delta_offset,
724     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
725 
726 {
727 	const struct got_error *err;
728 	off_t base_offset;
729 	uint8_t base_type;
730 	uint64_t base_size;
731 	size_t base_tslen;
732 	off_t delta_data_offset;
733 	uint8_t *delta_buf;
734 	size_t delta_len, consumed;
735 
736 	err = parse_offset_delta(&base_offset, &consumed, pack,
737 	    delta_offset, tslen);
738 	if (err)
739 		return err;
740 
741 	delta_data_offset = delta_offset + tslen + consumed;
742 	if (delta_data_offset >= pack->filesize)
743 		return got_error(GOT_ERR_PACK_OFFSET);
744 
745 	if (pack->map == NULL) {
746 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
747 		if (delta_data_offset == -1)
748 			return got_error_from_errno("lseek");
749 	}
750 
751 	if (pack->map) {
752 		size_t mapoff = (size_t)delta_data_offset;
753 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
754 		    mapoff, pack->filesize - mapoff);
755 		if (err)
756 			return err;
757 	} else {
758 
759 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
760 		if (err)
761 			return err;
762 	}
763 
764 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
765 	    delta_data_offset, delta_buf, delta_len);
766 	if (err)
767 		return err;
768 
769 	/* An offset delta must be in the same packfile. */
770 	if (base_offset >= pack->filesize)
771 		return got_error(GOT_ERR_PACK_OFFSET);
772 
773 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
774 	    pack, base_offset);
775 	if (err)
776 		return err;
777 
778 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
779 	    base_tslen, base_type, base_size, recursion - 1);
780 }
781 
782 static const struct got_error *
783 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
784     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
785     size_t delta_size, unsigned int recursion)
786 {
787 	const struct got_error *err;
788 	struct got_object_id id;
789 	int idx;
790 	off_t base_offset;
791 	uint8_t base_type;
792 	uint64_t base_size;
793 	size_t base_tslen;
794 	off_t delta_data_offset;
795 	uint8_t *delta_buf;
796 	size_t delta_len;
797 
798 	if (delta_offset >= pack->filesize)
799 		return got_error(GOT_ERR_PACK_OFFSET);
800 	delta_data_offset = delta_offset + tslen;
801 	if (delta_data_offset >= pack->filesize)
802 		return got_error(GOT_ERR_PACK_OFFSET);
803 
804 	if (pack->map == NULL) {
805 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
806 		if (delta_data_offset == -1)
807 			return got_error_from_errno("lseek");
808 	}
809 
810 	if (pack->map) {
811 		size_t mapoff = (size_t)delta_data_offset;
812 		memcpy(&id, pack->map + mapoff, sizeof(id));
813 		mapoff += sizeof(id);
814 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
815 		    mapoff, pack->filesize - mapoff);
816 		if (err)
817 			return err;
818 	} else {
819 		ssize_t n = read(pack->fd, &id, sizeof(id));
820 		if (n < 0)
821 			return got_error_from_errno("read");
822 		if (n != sizeof(id))
823 			return got_error(GOT_ERR_BAD_PACKFILE);
824 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
825 		if (err)
826 			return err;
827 	}
828 
829 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
830 	    delta_data_offset, delta_buf, delta_len);
831 	if (err)
832 		return err;
833 
834 	/* Delta base must be in the same pack file. */
835 	idx = got_packidx_get_object_idx(packidx, &id);
836 	if (idx == -1)
837 		return got_error(GOT_ERR_BAD_PACKFILE);
838 
839 	base_offset = get_object_offset(packidx, idx);
840 	if (base_offset == (uint64_t)-1)
841 		return got_error(GOT_ERR_BAD_PACKIDX);
842 
843 	if (base_offset >= pack->filesize)
844 		return got_error(GOT_ERR_PACK_OFFSET);
845 
846 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
847 	    pack, base_offset);
848 	if (err)
849 		return err;
850 
851 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
852 	    base_tslen, base_type, base_size, recursion - 1);
853 }
854 
855 static const struct got_error *
856 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
857     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
858     size_t delta_size, unsigned int recursion)
859 {
860 	const struct got_error *err = NULL;
861 
862 	if (--recursion == 0)
863 		return got_error(GOT_ERR_RECURSION);
864 
865 	switch (delta_type) {
866 	case GOT_OBJ_TYPE_COMMIT:
867 	case GOT_OBJ_TYPE_TREE:
868 	case GOT_OBJ_TYPE_BLOB:
869 	case GOT_OBJ_TYPE_TAG:
870 		/* Plain types are the final delta base. Recursion ends. */
871 		err = add_delta(deltas, delta_offset, tslen, delta_type,
872 		    delta_size, 0, NULL, 0);
873 		break;
874 	case GOT_OBJ_TYPE_OFFSET_DELTA:
875 		err = resolve_offset_delta(deltas, packidx, pack,
876 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
877 		break;
878 	case GOT_OBJ_TYPE_REF_DELTA:
879 		err = resolve_ref_delta(deltas, packidx, pack,
880 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
881 		break;
882 	default:
883 		return got_error(GOT_ERR_OBJ_TYPE);
884 	}
885 
886 	return err;
887 }
888 
889 static const struct got_error *
890 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
891     struct got_pack *pack, struct got_object_id *id, off_t offset,
892     size_t tslen, int delta_type, size_t delta_size, int idx)
893 {
894 	const struct got_error *err = NULL;
895 	int resolved_type;
896 
897 	*obj = calloc(1, sizeof(**obj));
898 	if (*obj == NULL)
899 		return got_error_from_errno("calloc");
900 
901 	(*obj)->flags = 0;
902 	(*obj)->hdrlen = 0;
903 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
904 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
905 	(*obj)->pack_offset = offset + tslen;
906 
907 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
908 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
909 
910 	(*obj)->path_packfile = strdup(pack->path_packfile);
911 	if ((*obj)->path_packfile == NULL) {
912 		err = got_error_from_errno("strdup");
913 		goto done;
914 	}
915 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
916 	(*obj)->pack_idx = idx;
917 
918 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
919 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
920 	if (err)
921 		goto done;
922 
923 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
924 	if (err)
925 		goto done;
926 	(*obj)->type = resolved_type;
927 done:
928 	if (err) {
929 		got_object_close(*obj);
930 		*obj = NULL;
931 	}
932 	return err;
933 }
934 
935 const struct got_error *
936 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
937     struct got_packidx *packidx, int idx, struct got_object_id *id)
938 {
939 	const struct got_error *err = NULL;
940 	off_t offset;
941 	uint8_t type;
942 	uint64_t size;
943 	size_t tslen;
944 
945 	*obj = NULL;
946 
947 	offset = get_object_offset(packidx, idx);
948 	if (offset == (uint64_t)-1)
949 		return got_error(GOT_ERR_BAD_PACKIDX);
950 
951 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
952 	if (err)
953 		return err;
954 
955 	switch (type) {
956 	case GOT_OBJ_TYPE_COMMIT:
957 	case GOT_OBJ_TYPE_TREE:
958 	case GOT_OBJ_TYPE_BLOB:
959 	case GOT_OBJ_TYPE_TAG:
960 		err = open_plain_object(obj, pack->path_packfile, id, type,
961 		    offset + tslen, size, idx);
962 		break;
963 	case GOT_OBJ_TYPE_OFFSET_DELTA:
964 	case GOT_OBJ_TYPE_REF_DELTA:
965 		err = open_delta_object(obj, packidx, pack, id, offset,
966 		    tslen, type, size, idx);
967 		break;
968 	default:
969 		err = got_error(GOT_ERR_OBJ_TYPE);
970 		break;
971 	}
972 
973 	return err;
974 }
975 
976 static const struct got_error *
977 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
978 {
979 	struct got_delta *delta;
980 	uint64_t base_size = 0, result_size = 0;
981 
982 	*max_size = 0;
983 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
984 		/* Plain object types are the delta base. */
985 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
986 		    delta->type != GOT_OBJ_TYPE_TREE &&
987 		    delta->type != GOT_OBJ_TYPE_BLOB &&
988 		    delta->type != GOT_OBJ_TYPE_TAG) {
989 			const struct got_error *err;
990 			err = got_delta_get_sizes(&base_size, &result_size,
991 			    delta->delta_buf, delta->delta_len);
992 			if (err)
993 				return err;
994 		} else
995 			base_size = delta->size;
996 		if (base_size > *max_size)
997 			*max_size = base_size;
998 		if (result_size > *max_size)
999 			*max_size = result_size;
1000 	}
1001 
1002 	return NULL;
1003 }
1004 
1005 const struct got_error *
1006 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj)
1007 {
1008 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1009 		return got_error(GOT_ERR_OBJ_TYPE);
1010 
1011 	return get_delta_chain_max_size(size, &obj->deltas);
1012 }
1013 
1014 static const struct got_error *
1015 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1016     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
1017 {
1018 	const struct got_error *err = NULL;
1019 	struct got_delta *delta;
1020 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1021 	size_t base_bufsz = 0, accum_size = 0;
1022 	uint64_t max_size;
1023 	int n = 0;
1024 
1025 	*result_size = 0;
1026 
1027 	if (SIMPLEQ_EMPTY(&deltas->entries))
1028 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1029 
1030 	/* We process small enough files entirely in memory for speed. */
1031 	err = get_delta_chain_max_size(&max_size, deltas);
1032 	if (err)
1033 		return err;
1034 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1035 		accum_buf = malloc(max_size);
1036 		if (accum_buf == NULL)
1037 			return got_error_from_errno("malloc");
1038 		base_file = NULL;
1039 		accum_file = NULL;
1040 	}
1041 
1042 	/* Deltas are ordered in ascending order. */
1043 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1044 		if (n == 0) {
1045 			size_t mapoff;
1046 			off_t delta_data_offset;
1047 
1048 			/* Plain object types are the delta base. */
1049 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1050 			    delta->type != GOT_OBJ_TYPE_TREE &&
1051 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1052 			    delta->type != GOT_OBJ_TYPE_TAG) {
1053 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1054 				goto done;
1055 			}
1056 
1057 			delta_data_offset = delta->offset + delta->tslen;
1058 			if (delta_data_offset >= pack->filesize) {
1059 				err = got_error(GOT_ERR_PACK_OFFSET);
1060 				goto done;
1061 			}
1062 			if (pack->map == NULL) {
1063 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1064 				    == -1) {
1065 					err = got_error_from_errno("lseek");
1066 					goto done;
1067 				}
1068 			}
1069 			if (base_file) {
1070 				if (pack->map) {
1071 					mapoff = (size_t)delta_data_offset;
1072 					err = got_inflate_to_file_mmap(
1073 					    &base_bufsz, pack->map, mapoff,
1074 					    pack->filesize - mapoff, base_file);
1075 				} else
1076 					err = got_inflate_to_file_fd(
1077 					    &base_bufsz, pack->fd, base_file);
1078 			} else {
1079 				if (pack->map) {
1080 					mapoff = (size_t)delta_data_offset;
1081 					err = got_inflate_to_mem_mmap(&base_buf,
1082 					    &base_bufsz, pack->map, mapoff,
1083 					    pack->filesize - mapoff);
1084 				} else
1085 					err = got_inflate_to_mem_fd(&base_buf,
1086 					    &base_bufsz, pack->fd);
1087 			}
1088 			if (err)
1089 				goto done;
1090 			n++;
1091 			if (base_file)
1092 				rewind(base_file);
1093 			continue;
1094 		}
1095 
1096 		if (base_buf) {
1097 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1098 			    delta->delta_buf, delta->delta_len, accum_buf,
1099 			    &accum_size, max_size);
1100 			n++;
1101 		} else {
1102 			err = got_delta_apply(base_file, delta->delta_buf,
1103 			    delta->delta_len,
1104 			    /* Final delta application writes to output file. */
1105 			    ++n < deltas->nentries ? accum_file : outfile,
1106 			    &accum_size);
1107 		}
1108 		if (err)
1109 			goto done;
1110 
1111 		if (n < deltas->nentries) {
1112 			/* Accumulated delta becomes the new base. */
1113 			if (base_buf) {
1114 				uint8_t *tmp = accum_buf;
1115 				/*
1116 				 * Base buffer switches roles with accumulation
1117 				 * buffer. Ensure it can hold the largest
1118 				 * result in the delta chain. The initial
1119 				 * allocation might have been smaller.
1120 				 */
1121 				if (base_bufsz < max_size) {
1122 					uint8_t *p;
1123 					p = reallocarray(base_buf, 1, max_size);
1124 					if (p == NULL) {
1125 						err = got_error_from_errno(
1126 						    "reallocarray");
1127 						goto done;
1128 					}
1129 					base_buf = p;
1130 					base_bufsz = max_size;
1131 				}
1132 				accum_buf = base_buf;
1133 				base_buf = tmp;
1134 			} else {
1135 				FILE *tmp = accum_file;
1136 				accum_file = base_file;
1137 				base_file = tmp;
1138 				rewind(base_file);
1139 				rewind(accum_file);
1140 			}
1141 		}
1142 	}
1143 
1144 done:
1145 	free(base_buf);
1146 	if (accum_buf) {
1147 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1148 		free(accum_buf);
1149 		if (len != accum_size)
1150 			err = got_ferror(outfile, GOT_ERR_IO);
1151 	}
1152 	rewind(outfile);
1153 	if (err == NULL)
1154 		*result_size = accum_size;
1155 	return err;
1156 }
1157 
1158 static const struct got_error *
1159 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1160     struct got_delta_chain *deltas, struct got_pack *pack)
1161 {
1162 	const struct got_error *err = NULL;
1163 	struct got_delta *delta;
1164 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1165 	size_t base_bufsz = 0, accum_size = 0;
1166 	uint64_t max_size;
1167 	int n = 0;
1168 
1169 	*outbuf = NULL;
1170 	*outlen = 0;
1171 
1172 	if (SIMPLEQ_EMPTY(&deltas->entries))
1173 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1174 
1175 	err = get_delta_chain_max_size(&max_size, deltas);
1176 	if (err)
1177 		return err;
1178 	accum_buf = malloc(max_size);
1179 	if (accum_buf == NULL)
1180 		return got_error_from_errno("malloc");
1181 
1182 	/* Deltas are ordered in ascending order. */
1183 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1184 		if (n == 0) {
1185 			size_t delta_data_offset;
1186 
1187 			/* Plain object types are the delta base. */
1188 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1189 			    delta->type != GOT_OBJ_TYPE_TREE &&
1190 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1191 			    delta->type != GOT_OBJ_TYPE_TAG) {
1192 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1193 				goto done;
1194 			}
1195 
1196 			delta_data_offset = delta->offset + delta->tslen;
1197 			if (delta_data_offset >= pack->filesize) {
1198 				err = got_error(GOT_ERR_PACK_OFFSET);
1199 				goto done;
1200 			}
1201 			if (pack->map) {
1202 				size_t mapoff = (size_t)delta_data_offset;
1203 				err = got_inflate_to_mem_mmap(&base_buf,
1204 				    &base_bufsz, pack->map, mapoff,
1205 				    pack->filesize - mapoff);
1206 			} else {
1207 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1208 				    == -1) {
1209 					err = got_error_from_errno("lseek");
1210 					goto done;
1211 				}
1212 				err = got_inflate_to_mem_fd(&base_buf,
1213 				    &base_bufsz, pack->fd);
1214 			}
1215 			if (err)
1216 				goto done;
1217 			n++;
1218 			continue;
1219 		}
1220 
1221 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1222 		    delta->delta_buf, delta->delta_len, accum_buf,
1223 		    &accum_size, max_size);
1224 		n++;
1225 		if (err)
1226 			goto done;
1227 
1228 		if (n < deltas->nentries) {
1229 			/* Accumulated delta becomes the new base. */
1230 			uint8_t *tmp = accum_buf;
1231 			/*
1232 			 * Base buffer switches roles with accumulation buffer.
1233 			 * Ensure it can hold the largest result in the delta
1234 			 * chain. Initial allocation might have been smaller.
1235 			 */
1236 			if (base_bufsz < max_size) {
1237 				uint8_t *p;
1238 				p = reallocarray(base_buf, 1, max_size);
1239 				if (p == NULL) {
1240 					err = got_error_from_errno(
1241 					    "reallocarray");
1242 					goto done;
1243 				}
1244 				base_buf = p;
1245 				base_bufsz = max_size;
1246 			}
1247 			accum_buf = base_buf;
1248 			base_buf = tmp;
1249 		}
1250 	}
1251 
1252 done:
1253 	free(base_buf);
1254 	if (err) {
1255 		free(accum_buf);
1256 		*outbuf = NULL;
1257 		*outlen = 0;
1258 	} else {
1259 		*outbuf = accum_buf;
1260 		*outlen = accum_size;
1261 	}
1262 	return err;
1263 }
1264 
1265 const struct got_error *
1266 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1267     FILE *outfile, FILE *base_file, FILE *accum_file)
1268 {
1269 	const struct got_error *err = NULL;
1270 
1271 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1272 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1273 
1274 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1275 		if (obj->pack_offset >= pack->filesize)
1276 			return got_error(GOT_ERR_PACK_OFFSET);
1277 
1278 		if (pack->map) {
1279 			size_t mapoff = (size_t)obj->pack_offset;
1280 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1281 			    mapoff, pack->filesize - mapoff, outfile);
1282 		} else {
1283 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1284 				return got_error_from_errno("lseek");
1285 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1286 			    outfile);
1287 		}
1288 	} else
1289 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1290 		    outfile, base_file, accum_file);
1291 
1292 	return err;
1293 }
1294 
1295 const struct got_error *
1296 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1297     struct got_object *obj, struct got_pack *pack)
1298 {
1299 	const struct got_error *err = NULL;
1300 
1301 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1302 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1303 
1304 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1305 		if (obj->pack_offset >= pack->filesize)
1306 			return got_error(GOT_ERR_PACK_OFFSET);
1307 		if (pack->map) {
1308 			size_t mapoff = (size_t)obj->pack_offset;
1309 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1310 			    mapoff, pack->filesize - mapoff);
1311 		} else {
1312 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1313 				return got_error_from_errno("lseek");
1314 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1315 		}
1316 	} else
1317 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1318 
1319 	return err;
1320 }