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_privsep.h"
45 #include "got_lib_pack.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #ifndef MIN
52 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
53 #endif
54 
55 static const struct got_error *
56 verify_fanout_table(uint32_t *fanout_table)
57 {
58 	int i;
59 
60 	for (i = 0; i < 0xff - 1; i++) {
61 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
62 			return got_error(GOT_ERR_BAD_PACKIDX);
63 	}
64 
65 	return NULL;
66 }
67 
68 const struct got_error *
69 got_packidx_init_hdr(struct got_packidx *p, int verify)
70 {
71 	const struct got_error *err = NULL;
72 	struct got_packidx_v2_hdr *h;
73 	SHA1_CTX ctx;
74 	uint8_t sha1[SHA1_DIGEST_LENGTH];
75 	size_t nobj, len_fanout, len_ids, offset, remain;
76 	ssize_t n;
77 
78 	SHA1Init(&ctx);
79 
80 	h = &p->hdr;
81 	offset = 0;
82 	remain = p->len;
83 
84 	if (remain < sizeof(*h->magic)) {
85 		err = got_error(GOT_ERR_BAD_PACKIDX);
86 		goto done;
87 	}
88 	if (p->map)
89 		h->magic = (uint32_t *)(p->map + offset);
90 	else {
91 		h->magic = malloc(sizeof(*h->magic));
92 		if (h->magic == NULL) {
93 			err = got_error_from_errno("malloc");
94 			goto done;
95 		}
96 		n = read(p->fd, h->magic, sizeof(*h->magic));
97 		if (n < 0)
98 			err = got_error_from_errno("read");
99 		else if (n != sizeof(*h->magic)) {
100 			err = got_error(GOT_ERR_BAD_PACKIDX);
101 			goto done;
102 		}
103 	}
104 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
105 		err = got_error(GOT_ERR_BAD_PACKIDX);
106 		goto done;
107 	}
108 	offset += sizeof(*h->magic);
109 	remain -= sizeof(*h->magic);
110 
111 	if (verify)
112 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
113 
114 	if (remain < sizeof(*h->version)) {
115 		err = got_error(GOT_ERR_BAD_PACKIDX);
116 		goto done;
117 	}
118 	if (p->map)
119 		h->version = (uint32_t *)(p->map + offset);
120 	else {
121 		h->version = malloc(sizeof(*h->version));
122 		if (h->version == NULL) {
123 			err = got_error_from_errno("malloc");
124 			goto done;
125 		}
126 		n = read(p->fd, h->version, sizeof(*h->version));
127 		if (n < 0)
128 			err = got_error_from_errno("read");
129 		else if (n != sizeof(*h->version)) {
130 			err = got_error(GOT_ERR_BAD_PACKIDX);
131 			goto done;
132 		}
133 	}
134 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
135 		err = got_error(GOT_ERR_BAD_PACKIDX);
136 		goto done;
137 	}
138 	offset += sizeof(*h->version);
139 	remain -= sizeof(*h->version);
140 
141 	if (verify)
142 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
143 
144 	len_fanout =
145 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
146 	if (remain < len_fanout) {
147 		err = got_error(GOT_ERR_BAD_PACKIDX);
148 		goto done;
149 	}
150 	if (p->map)
151 		h->fanout_table = (uint32_t *)(p->map + offset);
152 	else {
153 		h->fanout_table = malloc(len_fanout);
154 		if (h->fanout_table == NULL) {
155 			err = got_error_from_errno("malloc");
156 			goto done;
157 		}
158 		n = read(p->fd, h->fanout_table, len_fanout);
159 		if (n < 0)
160 			err = got_error_from_errno("read");
161 		else if (n != len_fanout) {
162 			err = got_error(GOT_ERR_BAD_PACKIDX);
163 			goto done;
164 		}
165 	}
166 	err = verify_fanout_table(h->fanout_table);
167 	if (err)
168 		goto done;
169 	if (verify)
170 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
171 	offset += len_fanout;
172 	remain -= len_fanout;
173 
174 	nobj = betoh32(h->fanout_table[0xff]);
175 	len_ids = nobj * sizeof(*h->sorted_ids);
176 	if (len_ids <= nobj || len_ids > remain) {
177 		err = got_error(GOT_ERR_BAD_PACKIDX);
178 		goto done;
179 	}
180 	if (p->map)
181 		h->sorted_ids =
182 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
183 	else {
184 		h->sorted_ids = malloc(len_ids);
185 		if (h->sorted_ids == NULL) {
186 			err = got_error(GOT_ERR_BAD_PACKIDX);
187 			goto done;
188 		}
189 		n = read(p->fd, h->sorted_ids, len_ids);
190 		if (n < 0)
191 			err = got_error_from_errno("read");
192 		else if (n != len_ids) {
193 			err = got_error(GOT_ERR_BAD_PACKIDX);
194 			goto done;
195 		}
196 	}
197 	if (verify)
198 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
199 	offset += len_ids;
200 	remain -= len_ids;
201 
202 	if (remain < nobj * sizeof(*h->crc32)) {
203 		err = got_error(GOT_ERR_BAD_PACKIDX);
204 		goto done;
205 	}
206 	if (p->map)
207 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
208 	else {
209 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
210 		if (h->crc32 == NULL) {
211 			err = got_error_from_errno("malloc");
212 			goto done;
213 		}
214 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
215 		if (n < 0)
216 			err = got_error_from_errno("read");
217 		else if (n != nobj * sizeof(*h->crc32)) {
218 			err = got_error(GOT_ERR_BAD_PACKIDX);
219 			goto done;
220 		}
221 	}
222 	if (verify)
223 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
224 	remain -= nobj * sizeof(*h->crc32);
225 	offset += nobj * sizeof(*h->crc32);
226 
227 	if (remain < nobj * sizeof(*h->offsets)) {
228 		err = got_error(GOT_ERR_BAD_PACKIDX);
229 		goto done;
230 	}
231 	if (p->map)
232 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
233 	else {
234 		h->offsets = malloc(nobj * sizeof(*h->offsets));
235 		if (h->offsets == NULL) {
236 			err = got_error_from_errno("malloc");
237 			goto done;
238 		}
239 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
240 		if (n < 0)
241 			err = got_error_from_errno("read");
242 		else if (n != nobj * sizeof(*h->offsets)) {
243 			err = got_error(GOT_ERR_BAD_PACKIDX);
244 			goto done;
245 		}
246 	}
247 	if (verify)
248 		SHA1Update(&ctx, (uint8_t *)h->offsets,
249 		    nobj * sizeof(*h->offsets));
250 	remain -= nobj * sizeof(*h->offsets);
251 	offset += nobj * sizeof(*h->offsets);
252 
253 	/* Large file offsets are contained only in files > 2GB. */
254 	if (p->len <= 0x80000000)
255 		goto checksum;
256 
257 	if (remain < nobj * sizeof(*h->large_offsets)) {
258 		err = got_error(GOT_ERR_BAD_PACKIDX);
259 		goto done;
260 	}
261 	if (p->map)
262 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
263 	else {
264 		h->offsets = malloc(nobj * sizeof(*h->large_offsets));
265 		if (h->offsets == NULL) {
266 			err = got_error_from_errno("malloc");
267 			goto done;
268 		}
269 		n = read(p->fd, h->large_offsets,
270 		    nobj * sizeof(*h->large_offsets));
271 		if (n < 0)
272 			err = got_error_from_errno("read");
273 		else if (n != nobj * sizeof(*h->large_offsets)) {
274 			err = got_error(GOT_ERR_BAD_PACKIDX);
275 			goto done;
276 		}
277 	}
278 	if (verify)
279 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
280 		    nobj * sizeof(*h->large_offsets));
281 	remain -= nobj * sizeof(*h->large_offsets);
282 	offset += nobj * sizeof(*h->large_offsets);
283 
284 checksum:
285 	if (remain < sizeof(*h->trailer)) {
286 		err = got_error(GOT_ERR_BAD_PACKIDX);
287 		goto done;
288 	}
289 	if (p->map)
290 		h->trailer =
291 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
292 	else {
293 		h->trailer = malloc(sizeof(*h->trailer));
294 		if (h->trailer == NULL) {
295 			err = got_error_from_errno("malloc");
296 			goto done;
297 		}
298 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
299 		if (n < 0)
300 			err = got_error_from_errno("read");
301 		else if (n != sizeof(*h->trailer)) {
302 			err = got_error(GOT_ERR_BAD_PACKIDX);
303 			goto done;
304 		}
305 	}
306 	if (verify) {
307 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
308 		SHA1Final(sha1, &ctx);
309 		if (memcmp(h->trailer->packidx_sha1, sha1,
310 		    SHA1_DIGEST_LENGTH) != 0)
311 			err = got_error(GOT_ERR_PACKIDX_CSUM);
312 	}
313 done:
314 	return err;
315 }
316 
317 const struct got_error *
318 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
319 {
320 	const struct got_error *err = NULL;
321 	struct got_packidx *p;
322 	struct stat sb;
323 
324 	*packidx = NULL;
325 
326 	p = calloc(1, sizeof(*p));
327 	if (p == NULL)
328 		return got_error_from_errno("calloc");
329 
330 	p->fd = open(path, O_RDONLY | O_NOFOLLOW);
331 	if (p->fd == -1)
332 		return got_error_from_errno2("open", path);
333 
334 	if (fstat(p->fd, &sb) != 0) {
335 		err = got_error_from_errno2("fstat", path);
336 		close(p->fd);
337 		free(p);
338 		return err;
339 	}
340 	p->len = sb.st_size;
341 	if (p->len < sizeof(p->hdr)) {
342 		err = got_error(GOT_ERR_BAD_PACKIDX);
343 		close(p->fd);
344 		free(p);
345 		return err;
346 	}
347 
348 	p->path_packidx = strdup(path);
349 	if (p->path_packidx == NULL) {
350 		err = got_error_from_errno("strdup");
351 		goto done;
352 	}
353 
354 #ifndef GOT_PACK_NO_MMAP
355 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
356 	if (p->map == MAP_FAILED) {
357 		if (errno != ENOMEM) {
358 			err = got_error_from_errno("mmap");
359 			goto done;
360 		}
361 		p->map = NULL; /* fall back to read(2) */
362 	}
363 #endif
364 
365 	err = got_packidx_init_hdr(p, verify);
366 done:
367 	if (err)
368 		got_packidx_close(p);
369 	else
370 		*packidx = p;
371 
372 	return err;
373 }
374 
375 const struct got_error *
376 got_packidx_close(struct got_packidx *packidx)
377 {
378 	const struct got_error *err = NULL;
379 
380 	free(packidx->path_packidx);
381 	if (packidx->map) {
382 		if (munmap(packidx->map, packidx->len) == -1)
383 			err = got_error_from_errno("munmap");
384 	} else {
385 		free(packidx->hdr.magic);
386 		free(packidx->hdr.version);
387 		free(packidx->hdr.fanout_table);
388 		free(packidx->hdr.sorted_ids);
389 		free(packidx->hdr.crc32);
390 		free(packidx->hdr.offsets);
391 		free(packidx->hdr.large_offsets);
392 		free(packidx->hdr.trailer);
393 	}
394 	if (close(packidx->fd) != 0 && err == NULL)
395 		err = got_error_from_errno("close");
396 	free(packidx);
397 
398 	return err;
399 }
400 
401 static off_t
402 get_object_offset(struct got_packidx *packidx, int idx)
403 {
404 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
405 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
406 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
407 		uint64_t loffset;
408 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
409 		if (idx < 0 || idx > totobj ||
410 		    packidx->hdr.large_offsets == NULL)
411 			return -1;
412 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
413 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
414 	}
415 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
416 }
417 
418 int
419 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
420 {
421 	u_int8_t id0 = id->sha1[0];
422 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
423 	int left = 0, right = totobj - 1;
424 
425 	if (id0 > 0)
426 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
427 
428 	while (left <= right) {
429 		struct got_packidx_object_id *oid;
430 		int i, cmp;
431 
432 		i = ((left + right) / 2);
433 		oid = &packidx->hdr.sorted_ids[i];
434 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
435 		if (cmp == 0)
436 			return i;
437 		else if (cmp > 0)
438 			left = i + 1;
439 		else if (cmp < 0)
440 			right = i - 1;
441 	}
442 
443 	return -1;
444 }
445 
446 const struct got_error *
447 got_packidx_match_id_str_prefix(struct got_object_id **unique_id,
448     struct got_packidx *packidx, const char *id_str_prefix)
449 {
450 	u_int8_t id0;
451 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
452 	char hex[3];
453 	size_t prefix_len = strlen(id_str_prefix);
454 	struct got_packidx_object_id *oid;
455 	int i;
456 
457 	*unique_id = NULL;
458 
459 	if (prefix_len < 2)
460 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
461 
462 	hex[0] = id_str_prefix[0];
463 	hex[1] = id_str_prefix[1];
464 	hex[2] = '\0';
465 	if (!got_parse_xdigit(&id0, hex))
466 		return got_error(GOT_ERR_BAD_OBJ_ID_STR);
467 
468 	i = betoh32(packidx->hdr.fanout_table[id0 - 1]);
469 	if (i == 0)
470 		return NULL;
471 
472 	oid = &packidx->hdr.sorted_ids[i];
473 	while (i < totobj && oid->sha1[0] == id0) {
474 		char id_str[SHA1_DIGEST_STRING_LENGTH];
475 		int cmp;
476 
477 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
478 		        return got_error(GOT_ERR_NO_SPACE);
479 
480 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
481 		if (cmp < 0) {
482 			oid = &packidx->hdr.sorted_ids[++i];
483 			continue;
484 		} else if (cmp > 0)
485 			break;
486 
487 		if (*unique_id != NULL)
488 			return got_error(GOT_ERR_AMBIGUOUS_ID);
489 		*unique_id = malloc(sizeof(**unique_id));
490 		if (*unique_id == NULL)
491 			return got_error_from_errno("malloc");
492 		memcpy((*unique_id)->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
493 
494 		oid = &packidx->hdr.sorted_ids[++i];
495 	}
496 
497 	return NULL;
498 }
499 
500 const struct got_error *
501 got_pack_stop_privsep_child(struct got_pack *pack)
502 {
503 	const struct got_error *err = NULL;
504 
505 	if (pack->privsep_child == NULL)
506 		return NULL;
507 
508 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
509 	if (err)
510 		return err;
511 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
512 	if (close(pack->privsep_child->imsg_fd) != 0 && err == NULL)
513 		err = got_error_from_errno("close");
514 	free(pack->privsep_child);
515 	pack->privsep_child = NULL;
516 	return err;
517 }
518 
519 const struct got_error *
520 got_pack_close(struct got_pack *pack)
521 {
522 	const struct got_error *err = NULL;
523 
524 	err = got_pack_stop_privsep_child(pack);
525 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
526 		err = got_error_from_errno("munmap");
527 	if (pack->fd != -1 && close(pack->fd) != 0 && err == NULL)
528 		err = got_error_from_errno("close");
529 	pack->fd = -1;
530 	free(pack->path_packfile);
531 	pack->path_packfile = NULL;
532 	pack->filesize = 0;
533 
534 	return err;
535 }
536 
537 static const struct got_error *
538 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
539     struct got_pack *pack, off_t offset)
540 {
541 	uint8_t t = 0;
542 	uint64_t s = 0;
543 	uint8_t sizeN;
544 	size_t mapoff = 0;
545 	int i = 0;
546 
547 	*len = 0;
548 
549 	if (offset >= pack->filesize)
550 		return got_error(GOT_ERR_PACK_OFFSET);
551 
552 	if (pack->map) {
553 		mapoff = (size_t)offset;
554 	} else {
555 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
556 			return got_error_from_errno("lseek");
557 	}
558 
559 	do {
560 		/* We do not support size values which don't fit in 64 bit. */
561 		if (i > 9)
562 			return got_error(GOT_ERR_NO_SPACE);
563 
564 		if (pack->map) {
565 			sizeN = *(pack->map + mapoff);
566 			mapoff += sizeof(sizeN);
567 		} else {
568 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
569 			if (n < 0)
570 				return got_error_from_errno("read");
571 			if (n != sizeof(sizeN))
572 				return got_error(GOT_ERR_BAD_PACKFILE);
573 		}
574 		*len += sizeof(sizeN);
575 
576 		if (i == 0) {
577 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
578 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
579 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
580 		} else {
581 			size_t shift = 4 + 7 * (i - 1);
582 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
583 		}
584 		i++;
585 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
586 
587 	*type = t;
588 	*size = s;
589 	return NULL;
590 }
591 
592 static const struct got_error *
593 open_plain_object(struct got_object **obj, const char *path_packfile,
594     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
595 {
596 	*obj = calloc(1, sizeof(**obj));
597 	if (*obj == NULL)
598 		return got_error_from_errno("calloc");
599 
600 	(*obj)->path_packfile = strdup(path_packfile);
601 	if ((*obj)->path_packfile == NULL) {
602 		const struct got_error *err = got_error_from_errno("strdup");
603 		free(*obj);
604 		*obj = NULL;
605 		return err;
606 	}
607 
608 	(*obj)->type = type;
609 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
610 	(*obj)->pack_idx = idx;
611 	(*obj)->hdrlen = 0;
612 	(*obj)->size = size;
613 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
614 	(*obj)->pack_offset = offset;
615 
616 	return NULL;
617 }
618 
619 static const struct got_error *
620 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
621     off_t delta_offset)
622 {
623 	int64_t o = 0;
624 	uint8_t offN;
625 	int i = 0;
626 
627 	*len = 0;
628 
629 	do {
630 		/* We do not support offset values which don't fit in 64 bit. */
631 		if (i > 8)
632 			return got_error(GOT_ERR_NO_SPACE);
633 
634 		if (pack->map) {
635 			size_t mapoff;
636 			if (delta_offset >= pack->filesize)
637 				return got_error(GOT_ERR_PACK_OFFSET);
638 			mapoff = (size_t)delta_offset + *len;
639 			offN = *(pack->map + mapoff);
640 		} else {
641 			ssize_t n;
642 			n = read(pack->fd, &offN, sizeof(offN));
643 			if (n < 0)
644 				return got_error_from_errno("read");
645 			if (n != sizeof(offN))
646 				return got_error(GOT_ERR_BAD_PACKFILE);
647 		}
648 		*len += sizeof(offN);
649 
650 		if (i == 0)
651 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
652 		else {
653 			o++;
654 			o <<= 7;
655 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
656 		}
657 		i++;
658 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
659 
660 	*offset = o;
661 	return NULL;
662 }
663 
664 static const struct got_error *
665 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
666     off_t offset, int tslen)
667 {
668 	const struct got_error *err;
669 	int64_t negoffset;
670 	size_t negofflen;
671 
672 	*len = 0;
673 
674 	err = parse_negative_offset(&negoffset, &negofflen, pack,
675 	    offset + tslen);
676 	if (err)
677 		return err;
678 
679 	/* Compute the base object's offset (must be in the same pack file). */
680 	*base_offset = (offset - negoffset);
681 	if (*base_offset <= 0)
682 		return got_error(GOT_ERR_BAD_PACKFILE);
683 
684 	*len = negofflen;
685 	return NULL;
686 }
687 
688 static const struct got_error *
689 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
690     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
691 
692 static const struct got_error *
693 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
694     int delta_type, size_t delta_size, size_t delta_data_offset,
695     uint8_t *delta_buf, size_t delta_len)
696 {
697 	struct got_delta *delta;
698 
699 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
700 	    delta_data_offset, delta_buf,
701 	    delta_len);
702 	if (delta == NULL)
703 		return got_error_from_errno("got_delta_open");
704 	/* delta is freed in got_object_close() */
705 	deltas->nentries++;
706 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
707 	return NULL;
708 }
709 
710 static const struct got_error *
711 resolve_offset_delta(struct got_delta_chain *deltas,
712     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
713     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
714 
715 {
716 	const struct got_error *err;
717 	off_t base_offset;
718 	uint8_t base_type;
719 	uint64_t base_size;
720 	size_t base_tslen;
721 	off_t delta_data_offset;
722 	uint8_t *delta_buf;
723 	size_t delta_len, consumed;
724 
725 	err = parse_offset_delta(&base_offset, &consumed, pack,
726 	    delta_offset, tslen);
727 	if (err)
728 		return err;
729 
730 	delta_data_offset = delta_offset + tslen + consumed;
731 	if (delta_data_offset >= pack->filesize)
732 		return got_error(GOT_ERR_PACK_OFFSET);
733 
734 	if (pack->map == NULL) {
735 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
736 		if (delta_data_offset == -1)
737 			return got_error_from_errno("lseek");
738 	}
739 
740 	if (pack->map) {
741 		size_t mapoff = (size_t)delta_data_offset;
742 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
743 		    mapoff, pack->filesize - mapoff);
744 		if (err)
745 			return err;
746 	} else {
747 
748 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
749 		if (err)
750 			return err;
751 	}
752 
753 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
754 	    delta_data_offset, delta_buf, delta_len);
755 	if (err)
756 		return err;
757 
758 	/* An offset delta must be in the same packfile. */
759 	if (base_offset >= pack->filesize)
760 		return got_error(GOT_ERR_PACK_OFFSET);
761 
762 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
763 	    pack, base_offset);
764 	if (err)
765 		return err;
766 
767 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
768 	    base_tslen, base_type, base_size, recursion - 1);
769 }
770 
771 static const struct got_error *
772 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
773     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
774     size_t delta_size, unsigned int recursion)
775 {
776 	const struct got_error *err;
777 	struct got_object_id id;
778 	int idx;
779 	off_t base_offset;
780 	uint8_t base_type;
781 	uint64_t base_size;
782 	size_t base_tslen;
783 	off_t delta_data_offset;
784 	uint8_t *delta_buf;
785 	size_t delta_len;
786 
787 	if (delta_offset >= pack->filesize)
788 		return got_error(GOT_ERR_PACK_OFFSET);
789 	delta_data_offset = delta_offset + tslen;
790 	if (delta_data_offset >= pack->filesize)
791 		return got_error(GOT_ERR_PACK_OFFSET);
792 
793 	if (pack->map == NULL) {
794 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
795 		if (delta_data_offset == -1)
796 			return got_error_from_errno("lseek");
797 	}
798 
799 	if (pack->map) {
800 		size_t mapoff = (size_t)delta_data_offset;
801 		memcpy(&id, pack->map + mapoff, sizeof(id));
802 		mapoff += sizeof(id);
803 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
804 		    mapoff, pack->filesize - mapoff);
805 		if (err)
806 			return err;
807 	} else {
808 		ssize_t n = read(pack->fd, &id, sizeof(id));
809 		if (n < 0)
810 			return got_error_from_errno("read");
811 		if (n != sizeof(id))
812 			return got_error(GOT_ERR_BAD_PACKFILE);
813 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
814 		if (err)
815 			return err;
816 	}
817 
818 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
819 	    delta_data_offset, delta_buf, delta_len);
820 	if (err)
821 		return err;
822 
823 	/* Delta base must be in the same pack file. */
824 	idx = got_packidx_get_object_idx(packidx, &id);
825 	if (idx == -1)
826 		return got_error(GOT_ERR_BAD_PACKFILE);
827 
828 	base_offset = get_object_offset(packidx, idx);
829 	if (base_offset == (uint64_t)-1)
830 		return got_error(GOT_ERR_BAD_PACKIDX);
831 
832 	if (base_offset >= pack->filesize)
833 		return got_error(GOT_ERR_PACK_OFFSET);
834 
835 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
836 	    pack, base_offset);
837 	if (err)
838 		return err;
839 
840 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
841 	    base_tslen, base_type, base_size, recursion - 1);
842 }
843 
844 static const struct got_error *
845 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
846     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
847     size_t delta_size, unsigned int recursion)
848 {
849 	const struct got_error *err = NULL;
850 
851 	if (--recursion == 0)
852 		return got_error(GOT_ERR_RECURSION);
853 
854 	switch (delta_type) {
855 	case GOT_OBJ_TYPE_COMMIT:
856 	case GOT_OBJ_TYPE_TREE:
857 	case GOT_OBJ_TYPE_BLOB:
858 	case GOT_OBJ_TYPE_TAG:
859 		/* Plain types are the final delta base. Recursion ends. */
860 		err = add_delta(deltas, delta_offset, tslen, delta_type,
861 		    delta_size, 0, NULL, 0);
862 		break;
863 	case GOT_OBJ_TYPE_OFFSET_DELTA:
864 		err = resolve_offset_delta(deltas, packidx, pack,
865 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
866 		break;
867 	case GOT_OBJ_TYPE_REF_DELTA:
868 		err = resolve_ref_delta(deltas, packidx, pack,
869 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
870 		break;
871 	default:
872 		return got_error(GOT_ERR_OBJ_TYPE);
873 	}
874 
875 	return err;
876 }
877 
878 static const struct got_error *
879 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
880     struct got_pack *pack, struct got_object_id *id, off_t offset,
881     size_t tslen, int delta_type, size_t delta_size, int idx)
882 {
883 	const struct got_error *err = NULL;
884 	int resolved_type;
885 
886 	*obj = calloc(1, sizeof(**obj));
887 	if (*obj == NULL)
888 		return got_error_from_errno("calloc");
889 
890 	(*obj)->flags = 0;
891 	(*obj)->hdrlen = 0;
892 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
893 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
894 	(*obj)->pack_offset = offset + tslen;
895 
896 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
897 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
898 
899 	(*obj)->path_packfile = strdup(pack->path_packfile);
900 	if ((*obj)->path_packfile == NULL) {
901 		err = got_error_from_errno("strdup");
902 		goto done;
903 	}
904 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
905 	(*obj)->pack_idx = idx;
906 
907 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
908 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
909 	if (err)
910 		goto done;
911 
912 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
913 	if (err)
914 		goto done;
915 	(*obj)->type = resolved_type;
916 done:
917 	if (err) {
918 		got_object_close(*obj);
919 		*obj = NULL;
920 	}
921 	return err;
922 }
923 
924 const struct got_error *
925 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
926     struct got_packidx *packidx, int idx, struct got_object_id *id)
927 {
928 	const struct got_error *err = NULL;
929 	off_t offset;
930 	uint8_t type;
931 	uint64_t size;
932 	size_t tslen;
933 
934 	*obj = NULL;
935 
936 	offset = get_object_offset(packidx, idx);
937 	if (offset == (uint64_t)-1)
938 		return got_error(GOT_ERR_BAD_PACKIDX);
939 
940 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
941 	if (err)
942 		return err;
943 
944 	switch (type) {
945 	case GOT_OBJ_TYPE_COMMIT:
946 	case GOT_OBJ_TYPE_TREE:
947 	case GOT_OBJ_TYPE_BLOB:
948 	case GOT_OBJ_TYPE_TAG:
949 		err = open_plain_object(obj, pack->path_packfile, id, type,
950 		    offset + tslen, size, idx);
951 		break;
952 	case GOT_OBJ_TYPE_OFFSET_DELTA:
953 	case GOT_OBJ_TYPE_REF_DELTA:
954 		err = open_delta_object(obj, packidx, pack, id, offset,
955 		    tslen, type, size, idx);
956 		break;
957 	default:
958 		err = got_error(GOT_ERR_OBJ_TYPE);
959 		break;
960 	}
961 
962 	return err;
963 }
964 
965 static const struct got_error *
966 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
967 {
968 	struct got_delta *delta;
969 	uint64_t base_size = 0, result_size = 0;
970 
971 	*max_size = 0;
972 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
973 		/* Plain object types are the delta base. */
974 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
975 		    delta->type != GOT_OBJ_TYPE_TREE &&
976 		    delta->type != GOT_OBJ_TYPE_BLOB &&
977 		    delta->type != GOT_OBJ_TYPE_TAG) {
978 			const struct got_error *err;
979 			err = got_delta_get_sizes(&base_size, &result_size,
980 			    delta->delta_buf, delta->delta_len);
981 			if (err)
982 				return err;
983 		} else
984 			base_size = delta->size;
985 		if (base_size > *max_size)
986 			*max_size = base_size;
987 		if (result_size > *max_size)
988 			*max_size = result_size;
989 	}
990 
991 	return NULL;
992 }
993 
994 const struct got_error *
995 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj)
996 {
997 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
998 		return got_error(GOT_ERR_OBJ_TYPE);
999 
1000 	return get_delta_chain_max_size(size, &obj->deltas);
1001 }
1002 
1003 static const struct got_error *
1004 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1005     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
1006 {
1007 	const struct got_error *err = NULL;
1008 	struct got_delta *delta;
1009 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1010 	size_t base_bufsz = 0, accum_size = 0;
1011 	uint64_t max_size;
1012 	int n = 0;
1013 
1014 	*result_size = 0;
1015 
1016 	if (SIMPLEQ_EMPTY(&deltas->entries))
1017 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1018 
1019 	/* We process small enough files entirely in memory for speed. */
1020 	err = get_delta_chain_max_size(&max_size, deltas);
1021 	if (err)
1022 		return err;
1023 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1024 		accum_buf = malloc(max_size);
1025 		if (accum_buf == NULL)
1026 			return got_error_from_errno("malloc");
1027 		base_file = NULL;
1028 		accum_file = NULL;
1029 	}
1030 
1031 	/* Deltas are ordered in ascending order. */
1032 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1033 		if (n == 0) {
1034 			size_t mapoff;
1035 			off_t delta_data_offset;
1036 
1037 			/* Plain object types are the delta base. */
1038 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1039 			    delta->type != GOT_OBJ_TYPE_TREE &&
1040 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1041 			    delta->type != GOT_OBJ_TYPE_TAG) {
1042 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1043 				goto done;
1044 			}
1045 
1046 			delta_data_offset = delta->offset + delta->tslen;
1047 			if (delta_data_offset >= pack->filesize) {
1048 				err = got_error(GOT_ERR_PACK_OFFSET);
1049 				goto done;
1050 			}
1051 			if (pack->map == NULL) {
1052 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1053 				    == -1) {
1054 					err = got_error_from_errno("lseek");
1055 					goto done;
1056 				}
1057 			}
1058 			if (base_file) {
1059 				if (pack->map) {
1060 					mapoff = (size_t)delta_data_offset;
1061 					err = got_inflate_to_file_mmap(
1062 					    &base_bufsz, pack->map, mapoff,
1063 					    pack->filesize - mapoff, base_file);
1064 				} else
1065 					err = got_inflate_to_file_fd(
1066 					    &base_bufsz, pack->fd, base_file);
1067 			} else {
1068 				if (pack->map) {
1069 					mapoff = (size_t)delta_data_offset;
1070 					err = got_inflate_to_mem_mmap(&base_buf,
1071 					    &base_bufsz, pack->map, mapoff,
1072 					    pack->filesize - mapoff);
1073 				} else
1074 					err = got_inflate_to_mem_fd(&base_buf,
1075 					    &base_bufsz, pack->fd);
1076 			}
1077 			if (err)
1078 				goto done;
1079 			n++;
1080 			if (base_file)
1081 				rewind(base_file);
1082 			continue;
1083 		}
1084 
1085 		if (base_buf) {
1086 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1087 			    delta->delta_buf, delta->delta_len, accum_buf,
1088 			    &accum_size, max_size);
1089 			n++;
1090 		} else {
1091 			err = got_delta_apply(base_file, delta->delta_buf,
1092 			    delta->delta_len,
1093 			    /* Final delta application writes to output file. */
1094 			    ++n < deltas->nentries ? accum_file : outfile,
1095 			    &accum_size);
1096 		}
1097 		if (err)
1098 			goto done;
1099 
1100 		if (n < deltas->nentries) {
1101 			/* Accumulated delta becomes the new base. */
1102 			if (base_buf) {
1103 				uint8_t *tmp = accum_buf;
1104 				/*
1105 				 * Base buffer switches roles with accumulation
1106 				 * buffer. Ensure it can hold the largest
1107 				 * result in the delta chain. The initial
1108 				 * allocation might have been smaller.
1109 				 */
1110 				if (base_bufsz < max_size) {
1111 					uint8_t *p;
1112 					p = reallocarray(base_buf, 1, max_size);
1113 					if (p == NULL) {
1114 						err = got_error_from_errno(
1115 						    "reallocarray");
1116 						goto done;
1117 					}
1118 					base_buf = p;
1119 					base_bufsz = max_size;
1120 				}
1121 				accum_buf = base_buf;
1122 				base_buf = tmp;
1123 			} else {
1124 				FILE *tmp = accum_file;
1125 				accum_file = base_file;
1126 				base_file = tmp;
1127 				rewind(base_file);
1128 				rewind(accum_file);
1129 			}
1130 		}
1131 	}
1132 
1133 done:
1134 	free(base_buf);
1135 	if (accum_buf) {
1136 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1137 		free(accum_buf);
1138 		if (len != accum_size)
1139 			err = got_ferror(outfile, GOT_ERR_IO);
1140 	}
1141 	rewind(outfile);
1142 	if (err == NULL)
1143 		*result_size = accum_size;
1144 	return err;
1145 }
1146 
1147 static const struct got_error *
1148 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1149     struct got_delta_chain *deltas, struct got_pack *pack)
1150 {
1151 	const struct got_error *err = NULL;
1152 	struct got_delta *delta;
1153 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1154 	size_t base_bufsz = 0, accum_size = 0;
1155 	uint64_t max_size;
1156 	int n = 0;
1157 
1158 	*outbuf = NULL;
1159 	*outlen = 0;
1160 
1161 	if (SIMPLEQ_EMPTY(&deltas->entries))
1162 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1163 
1164 	err = get_delta_chain_max_size(&max_size, deltas);
1165 	if (err)
1166 		return err;
1167 	accum_buf = malloc(max_size);
1168 	if (accum_buf == NULL)
1169 		return got_error_from_errno("malloc");
1170 
1171 	/* Deltas are ordered in ascending order. */
1172 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1173 		if (n == 0) {
1174 			size_t delta_data_offset;
1175 
1176 			/* Plain object types are the delta base. */
1177 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1178 			    delta->type != GOT_OBJ_TYPE_TREE &&
1179 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1180 			    delta->type != GOT_OBJ_TYPE_TAG) {
1181 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1182 				goto done;
1183 			}
1184 
1185 			delta_data_offset = delta->offset + delta->tslen;
1186 			if (delta_data_offset >= pack->filesize) {
1187 				err = got_error(GOT_ERR_PACK_OFFSET);
1188 				goto done;
1189 			}
1190 			if (pack->map) {
1191 				size_t mapoff = (size_t)delta_data_offset;
1192 				err = got_inflate_to_mem_mmap(&base_buf,
1193 				    &base_bufsz, pack->map, mapoff,
1194 				    pack->filesize - mapoff);
1195 			} else {
1196 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1197 				    == -1) {
1198 					err = got_error_from_errno("lseek");
1199 					goto done;
1200 				}
1201 				err = got_inflate_to_mem_fd(&base_buf,
1202 				    &base_bufsz, pack->fd);
1203 			}
1204 			if (err)
1205 				goto done;
1206 			n++;
1207 			continue;
1208 		}
1209 
1210 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1211 		    delta->delta_buf, delta->delta_len, accum_buf,
1212 		    &accum_size, max_size);
1213 		n++;
1214 		if (err)
1215 			goto done;
1216 
1217 		if (n < deltas->nentries) {
1218 			/* Accumulated delta becomes the new base. */
1219 			uint8_t *tmp = accum_buf;
1220 			/*
1221 			 * Base buffer switches roles with accumulation buffer.
1222 			 * Ensure it can hold the largest result in the delta
1223 			 * chain. Initial allocation might have been smaller.
1224 			 */
1225 			if (base_bufsz < max_size) {
1226 				uint8_t *p;
1227 				p = reallocarray(base_buf, 1, max_size);
1228 				if (p == NULL) {
1229 					err = got_error_from_errno(
1230 					    "reallocarray");
1231 					goto done;
1232 				}
1233 				base_buf = p;
1234 				base_bufsz = max_size;
1235 			}
1236 			accum_buf = base_buf;
1237 			base_buf = tmp;
1238 		}
1239 	}
1240 
1241 done:
1242 	free(base_buf);
1243 	if (err) {
1244 		free(accum_buf);
1245 		*outbuf = NULL;
1246 		*outlen = 0;
1247 	} else {
1248 		*outbuf = accum_buf;
1249 		*outlen = accum_size;
1250 	}
1251 	return err;
1252 }
1253 
1254 const struct got_error *
1255 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1256     FILE *outfile, FILE *base_file, FILE *accum_file)
1257 {
1258 	const struct got_error *err = NULL;
1259 
1260 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1261 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1262 
1263 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1264 		if (obj->pack_offset >= pack->filesize)
1265 			return got_error(GOT_ERR_PACK_OFFSET);
1266 
1267 		if (pack->map) {
1268 			size_t mapoff = (size_t)obj->pack_offset;
1269 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1270 			    mapoff, pack->filesize - mapoff, outfile);
1271 		} else {
1272 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1273 				return got_error_from_errno("lseek");
1274 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1275 			    outfile);
1276 		}
1277 	} else
1278 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1279 		    outfile, base_file, accum_file);
1280 
1281 	return err;
1282 }
1283 
1284 const struct got_error *
1285 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1286     struct got_object *obj, struct got_pack *pack)
1287 {
1288 	const struct got_error *err = NULL;
1289 
1290 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1291 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1292 
1293 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1294 		if (obj->pack_offset >= pack->filesize)
1295 			return got_error(GOT_ERR_PACK_OFFSET);
1296 		if (pack->map) {
1297 			size_t mapoff = (size_t)obj->pack_offset;
1298 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1299 			    mapoff, pack->filesize - mapoff);
1300 		} else {
1301 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1302 				return got_error_from_errno("lseek");
1303 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1304 		}
1305 	} else
1306 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1307 
1308 	return err;
1309 }