Got Mirror

Blob

Date:: Sun Sep 9 14:33:32 2018 UTC
Message:: move pack caching code from pack.c to repository.c
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 #include <sys/mman.h>
21 
22 #include <fcntl.h>
23 #include <errno.h>
24 #include <stdio.h>
25 #include <stdint.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <limits.h>
29 #include <sha1.h>
30 #include <endian.h>
31 #include <zlib.h>
32 
33 #include "got_error.h"
34 #include "got_object.h"
35 #include "got_repository.h"
36 #include "got_opentemp.h"
37 
38 #include "got_lib_sha1.h"
39 #include "got_lib_pack.h"
40 #include "got_lib_path.h"
41 #include "got_lib_delta.h"
42 #include "got_lib_inflate.h"
43 #include "got_lib_object.h"
44 #include "got_lib_repository.h"
45 
46 #ifndef nitems
47 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
48 #endif
49 
50 #ifndef MIN
51 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
52 #endif
53 
54 static const struct got_error *
55 verify_fanout_table(uint32_t *fanout_table)
56 {
57 	int i;
58 
59 	for (i = 0; i < 0xff - 1; i++) {
60 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
61 			return got_error(GOT_ERR_BAD_PACKIDX);
62 	}
63 
64 	return NULL;
65 }
66 
67 const struct got_error *
68 got_pack_get_packfile_size(size_t *size, const char *path)
69 {
70 	struct stat sb;
71 	char *dot;
72 
73 	*size = 0;
74 
75 	dot = strrchr(path, '.');
76 	if (dot == NULL)
77 		return got_error(GOT_ERR_BAD_PATH);
78 
79 	/* Path must point to a pack index or to a pack file. */
80 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
81 		const struct got_error *err = NULL;
82 		char *path_pack;
83 		char base_path[PATH_MAX];
84 
85 		/* Convert pack index path to pack file path. */
86 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
87 			return got_error(GOT_ERR_NO_SPACE);
88 		dot = strrchr(base_path, '.');
89 		if (dot == NULL)
90 			return got_error(GOT_ERR_BAD_PATH);
91 		*dot = '\0';
92 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
93 			return got_error_from_errno();
94 
95 		if (stat(path_pack, &sb) != 0)
96 			err = got_error_from_errno();
97 		free(path_pack);
98 		if (err)
99 			return err;
100 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
101 		if (stat(path, &sb) != 0)
102 			return got_error_from_errno();
103 	} else
104 		return got_error(GOT_ERR_BAD_PATH);
105 
106 	*size = sb.st_size;
107 	return 0;
108 }
109 
110 const struct got_error *
111 got_packidx_init_hdr(struct got_packidx *p, int verify)
112 {
113 	const struct got_error *err = NULL;
114 	struct got_packidx_v2_hdr *h;
115 	SHA1_CTX ctx;
116 	uint8_t sha1[SHA1_DIGEST_LENGTH];
117 	size_t nobj, len_fanout, len_ids, offset, remain;
118 	ssize_t n;
119 
120 	SHA1Init(&ctx);
121 
122 	h = &p->hdr;
123 	offset = 0;
124 	remain = p->len;
125 
126 	if (remain < sizeof(*h->magic)) {
127 		err = got_error(GOT_ERR_BAD_PACKIDX);
128 		goto done;
129 	}
130 	if (p->map)
131 		h->magic = (uint32_t *)(p->map + offset);
132 	else {
133 		h->magic = malloc(sizeof(*h->magic));
134 		if (h->magic == NULL) {
135 			err = got_error_from_errno();
136 			goto done;
137 		}
138 		n = read(p->fd, h->magic, sizeof(*h->magic));
139 		if (n != sizeof(*h->magic)) {
140 			err = got_error(GOT_ERR_BAD_PACKIDX);
141 			goto done;
142 		}
143 	}
144 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
145 		err = got_error(GOT_ERR_BAD_PACKIDX);
146 		goto done;
147 	}
148 	offset += sizeof(*h->magic);
149 	remain -= sizeof(*h->magic);
150 
151 	if (verify)
152 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
153 
154 	if (remain < sizeof(*h->version)) {
155 		err = got_error(GOT_ERR_BAD_PACKIDX);
156 		goto done;
157 	}
158 	if (p->map)
159 		h->version = (uint32_t *)(p->map + offset);
160 	else {
161 		h->version = malloc(sizeof(*h->version));
162 		if (h->version == NULL) {
163 			err = got_error_from_errno();
164 			goto done;
165 		}
166 		n = read(p->fd, h->version, sizeof(*h->version));
167 		if (n != sizeof(*h->version)) {
168 			err = got_error(GOT_ERR_BAD_PACKIDX);
169 			goto done;
170 		}
171 	}
172 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
173 		err = got_error(GOT_ERR_BAD_PACKIDX);
174 		goto done;
175 	}
176 	offset += sizeof(*h->version);
177 	remain -= sizeof(*h->version);
178 
179 	if (verify)
180 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
181 
182 	len_fanout =
183 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
184 	if (remain < len_fanout) {
185 		err = got_error(GOT_ERR_BAD_PACKIDX);
186 		goto done;
187 	}
188 	if (p->map)
189 		h->fanout_table = (uint32_t *)(p->map + offset);
190 	else {
191 		h->fanout_table = malloc(len_fanout);
192 		if (h->fanout_table == NULL) {
193 			err = got_error_from_errno();
194 			goto done;
195 		}
196 		n = read(p->fd, h->fanout_table, len_fanout);
197 		if (n != len_fanout) {
198 			err = got_error(GOT_ERR_BAD_PACKIDX);
199 			goto done;
200 		}
201 	}
202 	err = verify_fanout_table(h->fanout_table);
203 	if (err)
204 		goto done;
205 	if (verify)
206 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
207 	offset += len_fanout;
208 	remain -= len_fanout;
209 
210 	nobj = betoh32(h->fanout_table[0xff]);
211 	len_ids = nobj * sizeof(*h->sorted_ids);
212 	if (len_ids <= nobj || len_ids > remain) {
213 		err = got_error(GOT_ERR_BAD_PACKIDX);
214 		goto done;
215 	}
216 	if (p->map)
217 		h->sorted_ids =
218 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
219 	else {
220 		h->sorted_ids = malloc(len_ids);
221 		if (h->sorted_ids == NULL) {
222 			err = got_error(GOT_ERR_BAD_PACKIDX);
223 			goto done;
224 		}
225 		n = read(p->fd, h->sorted_ids, len_ids);
226 		if (n != len_ids) {
227 			err = got_error(GOT_ERR_BAD_PACKIDX);
228 			goto done;
229 		}
230 	}
231 	if (verify)
232 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
233 	offset += len_ids;
234 	remain -= len_ids;
235 
236 	if (remain < nobj * sizeof(*h->crc32)) {
237 		err = got_error(GOT_ERR_BAD_PACKIDX);
238 		goto done;
239 	}
240 	if (p->map)
241 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
242 	else {
243 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
244 		if (h->crc32 == NULL) {
245 			err = got_error_from_errno();
246 			goto done;
247 		}
248 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
249 		if (n != nobj * sizeof(*h->crc32)) {
250 			err = got_error(GOT_ERR_BAD_PACKIDX);
251 			goto done;
252 		}
253 	}
254 	if (verify)
255 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
256 	remain -= nobj * sizeof(*h->crc32);
257 	offset += nobj * sizeof(*h->crc32);
258 
259 	if (remain < nobj * sizeof(*h->offsets)) {
260 		err = got_error(GOT_ERR_BAD_PACKIDX);
261 		goto done;
262 	}
263 	if (p->map)
264 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
265 	else {
266 		h->offsets = malloc(nobj * sizeof(*h->offsets));
267 		if (h->offsets == NULL) {
268 			err = got_error_from_errno();
269 			goto done;
270 		}
271 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
272 		if (n != nobj * sizeof(*h->offsets)) {
273 			err = got_error(GOT_ERR_BAD_PACKIDX);
274 			goto done;
275 		}
276 	}
277 	if (verify)
278 		SHA1Update(&ctx, (uint8_t *)h->offsets,
279 		    nobj * sizeof(*h->offsets));
280 	remain -= nobj * sizeof(*h->offsets);
281 	offset += nobj * sizeof(*h->offsets);
282 
283 	/* Large file offsets are contained only in files > 2GB. */
284 	if (p->len <= 0x80000000)
285 		goto checksum;
286 
287 	if (remain < nobj * sizeof(*h->large_offsets)) {
288 		err = got_error(GOT_ERR_BAD_PACKIDX);
289 		goto done;
290 	}
291 	if (p->map)
292 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
293 	else {
294 		h->offsets = malloc(nobj * sizeof(*h->large_offsets));
295 		if (h->offsets == NULL) {
296 			err = got_error_from_errno();
297 			goto done;
298 		}
299 		n = read(p->fd, h->large_offsets,
300 		    nobj * sizeof(*h->large_offsets));
301 		if (n != nobj * sizeof(*h->large_offsets)) {
302 			err = got_error(GOT_ERR_BAD_PACKIDX);
303 			goto done;
304 		}
305 	}
306 	if (verify)
307 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
308 		    nobj * sizeof(*h->large_offsets));
309 	remain -= nobj * sizeof(*h->large_offsets);
310 	offset += nobj * sizeof(*h->large_offsets);
311 
312 checksum:
313 	if (remain < sizeof(*h->trailer)) {
314 		err = got_error(GOT_ERR_BAD_PACKIDX);
315 		goto done;
316 	}
317 	if (p->map)
318 		h->trailer =
319 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
320 	else {
321 		h->trailer = malloc(sizeof(*h->trailer));
322 		if (h->trailer == NULL) {
323 			err = got_error_from_errno();
324 			goto done;
325 		}
326 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
327 		if (n != sizeof(*h->trailer)) {
328 			err = got_error(GOT_ERR_BAD_PACKIDX);
329 			goto done;
330 		}
331 	}
332 	if (verify) {
333 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
334 		SHA1Final(sha1, &ctx);
335 		if (memcmp(h->trailer->packidx_sha1, sha1,
336 		    SHA1_DIGEST_LENGTH) != 0)
337 			err = got_error(GOT_ERR_PACKIDX_CSUM);
338 	}
339 done:
340 	return err;
341 }
342 
343 const struct got_error *
344 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
345 {
346 	const struct got_error *err = NULL;
347 	struct got_packidx *p;
348 
349 	*packidx = NULL;
350 
351 	p = calloc(1, sizeof(*p));
352 	if (p == NULL)
353 		return got_error_from_errno();
354 
355 	p->fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
356 	if (p->fd == -1)
357 		return got_error_from_errno();
358 
359 	err = got_pack_get_packfile_size(&p->len, path);
360 	if (err) {
361 		close(p->fd);
362 		free(p);
363 		return err;
364 	}
365 	if (p->len < sizeof(p->hdr)) {
366 		err = got_error(GOT_ERR_BAD_PACKIDX);
367 		close(p->fd);
368 		free(p);
369 		return err;
370 	}
371 
372 	p->path_packidx = strdup(path);
373 	if (p->path_packidx == NULL) {
374 		err = got_error_from_errno();
375 		goto done;
376 	}
377 
378 #ifndef GOT_PACK_NO_MMAP
379 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
380 	if (p->map == MAP_FAILED)
381 		p->map = NULL; /* fall back to read(2) */
382 #endif
383 
384 	err = got_packidx_init_hdr(p, verify);
385 done:
386 	if (err)
387 		got_packidx_close(p);
388 	else
389 		*packidx = p;
390 
391 	return err;
392 }
393 
394 const struct got_error *
395 got_packidx_close(struct got_packidx *packidx)
396 {
397 	const struct got_error *err = NULL;
398 
399 	free(packidx->path_packidx);
400 	if (packidx->map) {
401 		if (munmap(packidx->map, packidx->len) == -1)
402 			err = got_error_from_errno();
403 	} else {
404 		free(packidx->hdr.magic);
405 		free(packidx->hdr.version);
406 		free(packidx->hdr.fanout_table);
407 		free(packidx->hdr.sorted_ids);
408 		free(packidx->hdr.crc32);
409 		free(packidx->hdr.offsets);
410 		free(packidx->hdr.large_offsets);
411 		free(packidx->hdr.trailer);
412 	}
413 	close(packidx->fd);
414 	free(packidx);
415 
416 	return err;
417 }
418 
419 static off_t
420 get_object_offset(struct got_packidx *packidx, int idx)
421 {
422 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
423 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
424 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
425 		uint64_t loffset;
426 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
427 		if (idx < 0 || idx > totobj ||
428 		    packidx->hdr.large_offsets == NULL)
429 			return -1;
430 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
431 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
432 	}
433 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
434 }
435 
436 int
437 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
438 {
439 	u_int8_t id0 = id->sha1[0];
440 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
441 	int left = 0, right = totobj - 1;
442 
443 	if (id0 > 0)
444 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
445 
446 	while (left <= right) {
447 		struct got_packidx_object_id *oid;
448 		int i, cmp;
449 
450 		i = ((left + right) / 2);
451 		oid = &packidx->hdr.sorted_ids[i];
452 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
453 		if (cmp == 0)
454 			return i;
455 		else if (cmp > 0)
456 			left = i + 1;
457 		else if (cmp < 0)
458 			right = i - 1;
459 	}
460 
461 	return -1;
462 }
463 
464 static const struct got_error *
465 get_packfile_path(char **path_packfile, struct got_packidx *packidx)
466 {
467 	size_t size;
468 
469 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
470 	size = strlen(packidx->path_packidx) + 2;
471 	if (size < GOT_PACKFILE_NAMELEN + 1)
472 		return got_error(GOT_ERR_BAD_PATH);
473 
474 	*path_packfile = calloc(size, sizeof(**path_packfile));
475 	if (*path_packfile == NULL)
476 		return got_error_from_errno();
477 
478 	/* Copy up to and excluding ".idx". */
479 	if (strlcpy(*path_packfile, packidx->path_packidx,
480 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
481 		return got_error(GOT_ERR_NO_SPACE);
482 
483 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
484 		return got_error(GOT_ERR_NO_SPACE);
485 
486 	return NULL;
487 }
488 
489 const struct got_error *
490 got_pack_close(struct got_pack *pack)
491 {
492 	const struct got_error *err = NULL;
493 
494 	if (pack->map && munmap(pack->map, pack->filesize) == -1)
495 		err = got_error_from_errno();
496 	close(pack->fd);
497 	pack->fd = -1;
498 	free(pack->path_packfile);
499 	pack->path_packfile = NULL;
500 	pack->filesize = 0;
501 
502 	return err;
503 }
504 
505 static const struct got_error *
506 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
507     struct got_pack *pack, off_t offset)
508 {
509 	uint8_t t = 0;
510 	uint64_t s = 0;
511 	uint8_t sizeN;
512 	size_t mapoff = 0;
513 	int i = 0;
514 
515 	*len = 0;
516 
517 	if (offset >= pack->filesize)
518 		return got_error(GOT_ERR_PACK_OFFSET);
519 
520 	if (pack->map) {
521 		mapoff = (size_t)offset;
522 	} else {
523 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
524 			return got_error_from_errno();
525 	}
526 
527 	do {
528 		/* We do not support size values which don't fit in 64 bit. */
529 		if (i > 9)
530 			return got_error(GOT_ERR_NO_SPACE);
531 
532 		if (pack->map) {
533 			sizeN = *(pack->map + mapoff);
534 			mapoff += sizeof(sizeN);
535 		} else {
536 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
537 			if (n < 0)
538 				return got_error_from_errno();
539 			if (n != sizeof(sizeN))
540 				return got_error(GOT_ERR_BAD_PACKFILE);
541 		}
542 		*len += sizeof(sizeN);
543 
544 		if (i == 0) {
545 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
546 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
547 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
548 		} else {
549 			size_t shift = 4 + 7 * (i - 1);
550 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
551 		}
552 		i++;
553 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
554 
555 	*type = t;
556 	*size = s;
557 	return NULL;
558 }
559 
560 static const struct got_error *
561 open_plain_object(struct got_object **obj, const char *path_packfile,
562     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
563 {
564 	*obj = calloc(1, sizeof(**obj));
565 	if (*obj == NULL)
566 		return got_error_from_errno();
567 
568 	(*obj)->path_packfile = strdup(path_packfile);
569 	if ((*obj)->path_packfile == NULL) {
570 		const struct got_error *err = got_error_from_errno();
571 		free(*obj);
572 		*obj = NULL;
573 		return err;
574 	}
575 
576 	(*obj)->type = type;
577 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
578 	(*obj)->hdrlen = 0;
579 	(*obj)->size = size;
580 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
581 	(*obj)->pack_offset = offset;
582 
583 	return NULL;
584 }
585 
586 static const struct got_error *
587 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
588     off_t delta_offset)
589 {
590 	int64_t o = 0;
591 	uint8_t offN;
592 	int i = 0;
593 
594 	*len = 0;
595 
596 	do {
597 		/* We do not support offset values which don't fit in 64 bit. */
598 		if (i > 8)
599 			return got_error(GOT_ERR_NO_SPACE);
600 
601 		if (pack->map) {
602 			size_t mapoff;
603 			if (delta_offset >= pack->filesize)
604 				return got_error(GOT_ERR_PACK_OFFSET);
605 			mapoff = (size_t)delta_offset + *len;
606 			offN = *(pack->map + mapoff);
607 		} else {
608 			ssize_t n;
609 			n = read(pack->fd, &offN, sizeof(offN));
610 			if (n < 0)
611 				return got_error_from_errno();
612 			if (n != sizeof(offN))
613 				return got_error(GOT_ERR_BAD_PACKFILE);
614 		}
615 		*len += sizeof(offN);
616 
617 		if (i == 0)
618 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
619 		else {
620 			o++;
621 			o <<= 7;
622 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
623 		}
624 		i++;
625 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
626 
627 	*offset = o;
628 	return NULL;
629 }
630 
631 static const struct got_error *
632 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
633     off_t offset, int tslen)
634 {
635 	const struct got_error *err;
636 	int64_t negoffset;
637 	size_t negofflen;
638 
639 	*len = 0;
640 
641 	err = parse_negative_offset(&negoffset, &negofflen, pack,
642 	    offset + tslen);
643 	if (err)
644 		return err;
645 
646 	/* Compute the base object's offset (must be in the same pack file). */
647 	*base_offset = (offset - negoffset);
648 	if (*base_offset <= 0)
649 		return got_error(GOT_ERR_BAD_PACKFILE);
650 
651 	*len = negofflen;
652 	return NULL;
653 }
654 
655 static const struct got_error *
656 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
657     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
658 
659 static const struct got_error *
660 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
661     int delta_type, size_t delta_size, size_t delta_data_offset,
662     uint8_t *delta_buf, size_t delta_len)
663 {
664 	struct got_delta *delta;
665 
666 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
667 	    delta_data_offset, delta_buf,
668 	    delta_len);
669 	if (delta == NULL)
670 		return got_error_from_errno();
671 	/* delta is freed in got_object_close() */
672 	deltas->nentries++;
673 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
674 	return NULL;
675 }
676 
677 static const struct got_error *
678 resolve_offset_delta(struct got_delta_chain *deltas,
679     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
680     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
681 
682 {
683 	const struct got_error *err;
684 	off_t base_offset;
685 	uint8_t base_type;
686 	uint64_t base_size;
687 	size_t base_tslen;
688 	off_t delta_data_offset;
689 	uint8_t *delta_buf;
690 	size_t delta_len, consumed;
691 
692 	err = parse_offset_delta(&base_offset, &consumed, pack,
693 	    delta_offset, tslen);
694 	if (err)
695 		return err;
696 
697 	delta_data_offset = delta_offset + tslen + consumed;
698 	if (delta_data_offset >= pack->filesize)
699 		return got_error(GOT_ERR_PACK_OFFSET);
700 
701 	if (pack->map == NULL) {
702 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
703 		if (delta_data_offset == -1)
704 			return got_error_from_errno();
705 	}
706 
707 	if (pack->map) {
708 		size_t mapoff = (size_t)delta_data_offset;
709 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
710 		    mapoff, pack->filesize - mapoff);
711 		if (err)
712 			return err;
713 	} else {
714 
715 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
716 		if (err)
717 			return err;
718 	}
719 
720 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
721 	    delta_data_offset, delta_buf, delta_len);
722 	if (err)
723 		goto done;
724 
725 	/* An offset delta must be in the same packfile. */
726 	if (base_offset >= pack->filesize) {
727 		err = got_error(GOT_ERR_PACK_OFFSET);
728 		goto done;
729 	}
730 
731 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
732 	    pack, base_offset);
733 	if (err)
734 		goto done;
735 
736 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
737 	    base_tslen, base_type, base_size, recursion - 1);
738 done:
739 	if (err)
740 		free(delta_buf);
741 	return err;
742 }
743 
744 static const struct got_error *
745 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
746     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
747     size_t delta_size, unsigned int recursion)
748 {
749 	const struct got_error *err;
750 	struct got_object_id id;
751 	int idx;
752 	off_t base_offset;
753 	uint8_t base_type;
754 	uint64_t base_size;
755 	size_t base_tslen;
756 	off_t delta_data_offset;
757 	uint8_t *delta_buf = NULL;
758 	size_t delta_len;
759 
760 	if (delta_offset >= pack->filesize)
761 		return got_error(GOT_ERR_PACK_OFFSET);
762 	delta_data_offset = delta_offset + tslen;
763 	if (delta_data_offset >= pack->filesize)
764 		return got_error(GOT_ERR_PACK_OFFSET);
765 
766 	if (pack->map == NULL) {
767 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
768 		if (delta_data_offset == -1)
769 			return got_error_from_errno();
770 	}
771 
772 
773 	if (pack->map) {
774 		size_t mapoff = (size_t)delta_data_offset;
775 		memcpy(&id, pack->map + mapoff, sizeof(id));
776 		mapoff += sizeof(id);
777 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
778 		    mapoff, pack->filesize - mapoff);
779 		if (err)
780 			goto done;
781 	} else {
782 		ssize_t n = read(pack->fd, &id, sizeof(id));
783 		if (n < 0)
784 			return got_error_from_errno();
785 		if (n != sizeof(id))
786 			return got_error(GOT_ERR_BAD_PACKFILE);
787 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
788 		if (err)
789 			goto done;
790 	}
791 
792 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
793 	    delta_data_offset, delta_buf, delta_len);
794 	if (err)
795 		goto done;
796 
797 	/* Delta base must be in the same pack file. */
798 	idx = got_packidx_get_object_idx(packidx, &id);
799 	if (idx == -1) {
800 		err = got_error(GOT_ERR_BAD_PACKFILE);
801 		goto done;
802 	}
803 
804 	base_offset = get_object_offset(packidx, idx);
805 	if (base_offset == (uint64_t)-1) {
806 		err = got_error(GOT_ERR_BAD_PACKIDX);
807 		goto done;
808 	}
809 
810 	if (base_offset >= pack->filesize) {
811 		err = got_error(GOT_ERR_PACK_OFFSET);
812 		goto done;
813 	}
814 
815 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
816 	    pack, base_offset);
817 	if (err)
818 		goto done;
819 
820 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
821 	    base_tslen, base_type, base_size, recursion - 1);
822 done:
823 	if (err)
824 		free(delta_buf);
825 	return err;
826 }
827 
828 static const struct got_error *
829 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
830     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
831     size_t delta_size, unsigned int recursion)
832 {
833 	const struct got_error *err = NULL;
834 
835 	if (--recursion == 0)
836 		return got_error(GOT_ERR_RECURSION);
837 
838 	switch (delta_type) {
839 	case GOT_OBJ_TYPE_COMMIT:
840 	case GOT_OBJ_TYPE_TREE:
841 	case GOT_OBJ_TYPE_BLOB:
842 	case GOT_OBJ_TYPE_TAG:
843 		/* Plain types are the final delta base. Recursion ends. */
844 		err = add_delta(deltas, delta_offset, tslen, delta_type,
845 		    delta_size, 0, NULL, 0);
846 		break;
847 	case GOT_OBJ_TYPE_OFFSET_DELTA:
848 		err = resolve_offset_delta(deltas, packidx, pack,
849 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
850 		break;
851 	case GOT_OBJ_TYPE_REF_DELTA:
852 		err = resolve_ref_delta(deltas, packidx, pack,
853 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
854 		break;
855 	default:
856 		return got_error(GOT_ERR_OBJ_TYPE);
857 	}
858 
859 	return err;
860 }
861 
862 static const struct got_error *
863 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
864     struct got_pack *pack, struct got_object_id *id, off_t offset,
865     size_t tslen, int delta_type, size_t delta_size)
866 {
867 	const struct got_error *err = NULL;
868 	int resolved_type;
869 
870 	*obj = calloc(1, sizeof(**obj));
871 	if (*obj == NULL)
872 		return got_error_from_errno();
873 
874 	(*obj)->flags = 0;
875 	(*obj)->hdrlen = 0;
876 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
877 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
878 	(*obj)->pack_offset = offset + tslen;
879 
880 	(*obj)->path_packfile = strdup(pack->path_packfile);
881 	if ((*obj)->path_packfile == NULL) {
882 		err = got_error_from_errno();
883 		goto done;
884 	}
885 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
886 
887 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
888 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
889 
890 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
891 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
892 	if (err)
893 		goto done;
894 
895 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
896 	if (err)
897 		goto done;
898 	(*obj)->type = resolved_type;
899 
900 done:
901 	if (err) {
902 		got_object_close(*obj);
903 		*obj = NULL;
904 	}
905 	return err;
906 }
907 
908 static const struct got_error *
909 open_packed_object(struct got_object **obj, struct got_pack *pack,
910     struct got_packidx *packidx, int idx, struct got_object_id *id)
911 {
912 	const struct got_error *err = NULL;
913 	off_t offset;
914 	uint8_t type;
915 	uint64_t size;
916 	size_t tslen;
917 
918 	*obj = NULL;
919 
920 	offset = get_object_offset(packidx, idx);
921 	if (offset == (uint64_t)-1)
922 		return got_error(GOT_ERR_BAD_PACKIDX);
923 
924 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
925 	if (err)
926 		return err;
927 
928 	switch (type) {
929 	case GOT_OBJ_TYPE_COMMIT:
930 	case GOT_OBJ_TYPE_TREE:
931 	case GOT_OBJ_TYPE_BLOB:
932 	case GOT_OBJ_TYPE_TAG:
933 		err = open_plain_object(obj, pack->path_packfile, id, type,
934 		    offset + tslen, size);
935 		break;
936 	case GOT_OBJ_TYPE_OFFSET_DELTA:
937 	case GOT_OBJ_TYPE_REF_DELTA:
938 		err = open_delta_object(obj, packidx, pack, id, offset,
939 		    tslen, type, size);
940 		break;
941 	default:
942 		err = got_error(GOT_ERR_OBJ_TYPE);
943 		break;
944 	}
945 
946 	return err;
947 }
948 
949 const struct got_error *
950 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
951     struct got_repository *repo)
952 {
953 	const struct got_error *err = NULL;
954 	struct got_packidx *packidx = NULL;
955 	struct got_pack *pack;
956 	int idx;
957 	char *path_packfile;
958 
959 	err = got_repo_search_packidx(&packidx, &idx, repo, id);
960 	if (err)
961 		return err;
962 
963 	err = get_packfile_path(&path_packfile, packidx);
964 	if (err)
965 		return err;
966 
967 	pack = got_repo_get_cached_pack(repo, path_packfile);
968 	if (pack == NULL) {
969 		err = got_repo_cache_pack(&pack, repo, path_packfile, packidx);
970 		if (err)
971 			goto done;
972 	}
973 
974 	err = open_packed_object(obj, pack, packidx, idx, id);
975 	if (err)
976 		goto done;
977 
978 	err = got_repo_cache_pack(NULL, repo, (*obj)->path_packfile, packidx);
979 done:
980 	free(path_packfile);
981 	return err;
982 }
983 
984 static const struct got_error *
985 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
986 {
987 	struct got_delta *delta;
988 	uint64_t base_size = 0, result_size = 0;
989 
990 	*max_size = 0;
991 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
992 		/* Plain object types are the delta base. */
993 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
994 		    delta->type != GOT_OBJ_TYPE_TREE &&
995 		    delta->type != GOT_OBJ_TYPE_BLOB &&
996 		    delta->type != GOT_OBJ_TYPE_TAG) {
997 			const struct got_error *err;
998 			err = got_delta_get_sizes(&base_size, &result_size,
999 			    delta->delta_buf, delta->delta_len);
1000 			if (err)
1001 				return err;
1002 		} else
1003 			base_size = delta->size;
1004 		if (base_size > *max_size)
1005 			*max_size = base_size;
1006 		if (result_size > *max_size)
1007 			*max_size = result_size;
1008 	}
1009 
1010 	return NULL;
1011 }
1012 
1013 static const struct got_error *
1014 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1015     struct got_pack *pack, FILE *outfile)
1016 {
1017 	const struct got_error *err = NULL;
1018 	struct got_delta *delta;
1019 	FILE *base_file = NULL, *accum_file = NULL;
1020 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1021 	size_t 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();
1038 	} else {
1039 		base_file = got_opentemp();
1040 		if (base_file == NULL)
1041 			return got_error_from_errno();
1042 
1043 		accum_file = got_opentemp();
1044 		if (accum_file == NULL) {
1045 			err = got_error_from_errno();
1046 			fclose(base_file);
1047 			return err;
1048 		}
1049 	}
1050 
1051 	/* Deltas are ordered in ascending order. */
1052 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1053 		if (n == 0) {
1054 			size_t base_len, mapoff;
1055 			off_t delta_data_offset;
1056 
1057 			/* Plain object types are the delta base. */
1058 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1059 			    delta->type != GOT_OBJ_TYPE_TREE &&
1060 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1061 			    delta->type != GOT_OBJ_TYPE_TAG) {
1062 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1063 				goto done;
1064 			}
1065 
1066 			delta_data_offset = delta->offset + delta->tslen;
1067 			if (delta_data_offset >= pack->filesize) {
1068 				err = got_error(GOT_ERR_PACK_OFFSET);
1069 				goto done;
1070 			}
1071 			if (pack->map == NULL) {
1072 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1073 				    == -1) {
1074 					err = got_error_from_errno();
1075 					goto done;
1076 				}
1077 			}
1078 			if (base_file) {
1079 				if (pack->map) {
1080 					mapoff = (size_t)delta_data_offset;
1081 					err = got_inflate_to_file_mmap(
1082 					    &base_len, pack->map, mapoff,
1083 					    pack->filesize - mapoff, base_file);
1084 				} else
1085 					err = got_inflate_to_file_fd(&base_len,
1086 					    pack->fd, base_file);
1087 			} else {
1088 				if (pack->map) {
1089 					mapoff = (size_t)delta_data_offset;
1090 					err = got_inflate_to_mem_mmap(&base_buf,
1091 					    &base_len, pack->map, mapoff,
1092 					    pack->filesize - mapoff);
1093 				} else
1094 					err = got_inflate_to_mem_fd(&base_buf,
1095 					    &base_len, pack->fd);
1096 				if (base_len < max_size) {
1097 					uint8_t *p;
1098 					p = reallocarray(base_buf, 1, max_size);
1099 					if (p == NULL) {
1100 						err = got_error_from_errno();
1101 						goto done;
1102 					}
1103 					base_buf = p;
1104 				}
1105 			}
1106 			if (err)
1107 				goto done;
1108 			n++;
1109 			if (base_file)
1110 				rewind(base_file);
1111 			continue;
1112 		}
1113 
1114 		if (base_buf) {
1115 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1116 			    delta->delta_len, accum_buf, &accum_size);
1117 			n++;
1118 		} else {
1119 			err = got_delta_apply(base_file, delta->delta_buf,
1120 			    delta->delta_len,
1121 			    /* Final delta application writes to output file. */
1122 			    ++n < deltas->nentries ? accum_file : outfile,
1123 			    &accum_size);
1124 		}
1125 		if (err)
1126 			goto done;
1127 
1128 		if (n < deltas->nentries) {
1129 			/* Accumulated delta becomes the new base. */
1130 			if (base_buf) {
1131 				uint8_t *tmp = accum_buf;
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 	if (base_file)
1153 		fclose(base_file);
1154 	if (accum_file)
1155 		fclose(accum_file);
1156 	rewind(outfile);
1157 	if (err == NULL)
1158 		*result_size = accum_size;
1159 	return err;
1160 }
1161 
1162 static const struct got_error *
1163 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1164     struct got_delta_chain *deltas, struct got_pack *pack)
1165 {
1166 	const struct got_error *err = NULL;
1167 	struct got_delta *delta;
1168 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1169 	size_t accum_size;
1170 	uint64_t max_size;
1171 	int n = 0;
1172 
1173 	*outbuf = NULL;
1174 	*outlen = 0;
1175 
1176 	if (SIMPLEQ_EMPTY(&deltas->entries))
1177 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1178 
1179 	err = get_delta_chain_max_size(&max_size, deltas);
1180 	if (err)
1181 		return err;
1182 	accum_buf = malloc(max_size);
1183 	if (accum_buf == NULL)
1184 		return got_error_from_errno();
1185 
1186 	/* Deltas are ordered in ascending order. */
1187 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1188 		if (n == 0) {
1189 			size_t base_len;
1190 			size_t delta_data_offset;
1191 
1192 			/* Plain object types are the delta base. */
1193 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1194 			    delta->type != GOT_OBJ_TYPE_TREE &&
1195 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1196 			    delta->type != GOT_OBJ_TYPE_TAG) {
1197 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1198 				goto done;
1199 			}
1200 
1201 			delta_data_offset = delta->offset + delta->tslen;
1202 			if (delta_data_offset >= pack->filesize) {
1203 				err = got_error(GOT_ERR_PACK_OFFSET);
1204 				goto done;
1205 			}
1206 			if (pack->map) {
1207 				size_t mapoff = (size_t)delta_data_offset;
1208 				err = got_inflate_to_mem_mmap(&base_buf,
1209 				    &base_len, pack->map, mapoff,
1210 				    pack->filesize - mapoff);
1211 			} else {
1212 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1213 				    == -1) {
1214 					err = got_error_from_errno();
1215 					goto done;
1216 				}
1217 				err = got_inflate_to_mem_fd(&base_buf,
1218 				    &base_len, pack->fd);
1219 			}
1220 			if (err)
1221 				goto done;
1222 			if (base_len < max_size) {
1223 				uint8_t *p;
1224 				p = reallocarray(base_buf, 1, max_size);
1225 				if (p == NULL) {
1226 					err = got_error_from_errno();
1227 					goto done;
1228 				}
1229 				base_buf = p;
1230 			}
1231 			n++;
1232 			continue;
1233 		}
1234 
1235 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1236 		    delta->delta_len, accum_buf, &accum_size);
1237 		n++;
1238 		if (err)
1239 			goto done;
1240 
1241 		if (n < deltas->nentries) {
1242 			/* Accumulated delta becomes the new base. */
1243 			uint8_t *tmp = accum_buf;
1244 			accum_buf = base_buf;
1245 			base_buf = tmp;
1246 		}
1247 	}
1248 
1249 done:
1250 	free(base_buf);
1251 	if (err) {
1252 		free(accum_buf);
1253 		*outbuf = NULL;
1254 		*outlen = 0;
1255 	} else {
1256 		*outbuf = accum_buf;
1257 		*outlen = accum_size;
1258 	}
1259 	return err;
1260 }
1261 
1262 const struct got_error *
1263 got_packfile_extract_object(FILE **f, struct got_object *obj,
1264     struct got_repository *repo)
1265 {
1266 	const struct got_error *err = NULL;
1267 	struct got_pack *pack;
1268 
1269 	*f = NULL;
1270 
1271 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1272 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1273 
1274 	pack = got_repo_get_cached_pack(repo, obj->path_packfile);
1275 	if (pack == NULL) {
1276 		err = got_repo_cache_pack(&pack, repo, obj->path_packfile, NULL);
1277 		if (err)
1278 			return err;
1279 	}
1280 
1281 	*f = got_opentemp();
1282 	if (*f == NULL) {
1283 		err = got_error_from_errno();
1284 		goto done;
1285 	}
1286 
1287 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1288 		if (obj->pack_offset >= pack->filesize) {
1289 			err = got_error(GOT_ERR_PACK_OFFSET);
1290 			goto done;
1291 		}
1292 
1293 		if (pack->map) {
1294 			size_t mapoff = (size_t)obj->pack_offset;
1295 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1296 			    mapoff, pack->filesize - mapoff, *f);
1297 		} else {
1298 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1299 				err = got_error_from_errno();
1300 				goto done;
1301 			}
1302 			err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1303 		}
1304 	} else
1305 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1306 		    *f);
1307 done:
1308 	if (err && *f) {
1309 		fclose(*f);
1310 		*f = NULL;
1311 	}
1312 	return err;
1313 }
1314 
1315 const struct got_error *
1316 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1317     struct got_object *obj, struct got_repository *repo)
1318 {
1319 	const struct got_error *err = NULL;
1320 	struct got_pack *pack;
1321 
1322 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1323 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1324 
1325 	pack = got_repo_get_cached_pack(repo, obj->path_packfile);
1326 	if (pack == NULL) {
1327 		err = got_repo_cache_pack(&pack, repo, obj->path_packfile, NULL);
1328 		if (err)
1329 			goto done;
1330 	}
1331 
1332 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1333 		if (obj->pack_offset >= pack->filesize) {
1334 			err = got_error(GOT_ERR_PACK_OFFSET);
1335 			goto done;
1336 		}
1337 		if (pack->map) {
1338 			size_t mapoff = (size_t)obj->pack_offset;
1339 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1340 			    mapoff, pack->filesize - mapoff);
1341 		} else {
1342 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1343 				err = got_error_from_errno();
1344 				goto done;
1345 			}
1346 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1347 		}
1348 	} else
1349 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1350 done:
1351 	return err;
1352 }