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Date:: Fri Jun 22 11:03:45 2018 UTC
Message:: use binary search to find objects in pack index
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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 
21 #include <dirent.h>
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_zbuf.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 #define GOT_PACK_PREFIX		"pack-"
51 #define GOT_PACKFILE_SUFFIX	".pack"
52 #define GOT_PACKIDX_SUFFIX		".idx"
53 #define GOT_PACKFILE_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
54 				SHA1_DIGEST_STRING_LENGTH - 1 + \
55 				strlen(GOT_PACKFILE_SUFFIX))
56 #define GOT_PACKIDX_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
57 				SHA1_DIGEST_STRING_LENGTH - 1 + \
58 				strlen(GOT_PACKIDX_SUFFIX))
59 
60 #ifndef MIN
61 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
62 #endif
63 
64 static const struct got_error *
65 verify_fanout_table(uint32_t *fanout_table)
66 {
67 	int i;
68 
69 	for (i = 0; i < 0xff - 1; i++) {
70 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
71 			return got_error(GOT_ERR_BAD_PACKIDX);
72 	}
73 
74 	return NULL;
75 }
76 
77 static const struct got_error *
78 get_packfile_size(size_t *size, const char *path)
79 {
80 	struct stat sb;
81 	char *dot;
82 
83 	*size = 0;
84 
85 	dot = strrchr(path, '.');
86 	if (dot == NULL)
87 		return got_error(GOT_ERR_BAD_PATH);
88 
89 	/* Path must point to a pack index or to a pack file. */
90 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
91 		const struct got_error *err = NULL;
92 		char *path_pack;
93 		char base_path[PATH_MAX];
94 
95 		/* Convert pack index path to pack file path. */
96 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
97 			return got_error(GOT_ERR_NO_SPACE);
98 		dot = strrchr(base_path, '.');
99 		if (dot == NULL)
100 			return got_error(GOT_ERR_BAD_PATH);
101 		*dot = '\0';
102 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
103 			return got_error_from_errno();
104 
105 		if (stat(path_pack, &sb) != 0)
106 			err = got_error_from_errno();
107 		free(path_pack);
108 		if (err)
109 			return err;
110 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
111 		if (stat(path, &sb) != 0)
112 			return got_error_from_errno();
113 	} else
114 		return got_error(GOT_ERR_BAD_PATH);
115 
116 	*size = sb.st_size;
117 	return 0;
118 }
119 
120 const struct got_error *
121 got_packidx_open(struct got_packidx **packidx, const char *path)
122 {
123 	struct got_packidx *p;
124 	struct got_packidx_v2_hdr *h;
125 	FILE *f;
126 	const struct got_error *err = NULL;
127 	size_t n, nobj, packfile_size;
128 	SHA1_CTX ctx;
129 	uint8_t sha1[SHA1_DIGEST_LENGTH];
130 
131 	*packidx = NULL;
132 
133 	SHA1Init(&ctx);
134 
135 	f = fopen(path, "rb");
136 	if (f == NULL)
137 		return got_error_from_errno();
138 
139 	err = get_packfile_size(&packfile_size, path);
140 	if (err)
141 		return err;
142 
143 	p = calloc(1, sizeof(*p));
144 	if (p == NULL)
145 		return got_error_from_errno();
146 	p->path_packidx = strdup(path);
147 	if (p->path_packidx == NULL) {
148 		err = got_error_from_errno();
149 		free(p->path_packidx);
150 		free(p);
151 		return err;
152 	}
153 
154 	h = &p->hdr;
155 	n = fread(&h->magic, sizeof(h->magic), 1, f);
156 	if (n != 1) {
157 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
158 		goto done;
159 	}
160 
161 	if (betoh32(h->magic) != GOT_PACKIDX_V2_MAGIC) {
162 		err = got_error(GOT_ERR_BAD_PACKIDX);
163 		goto done;
164 	}
165 
166 	SHA1Update(&ctx, (uint8_t *)&h->magic, sizeof(h->magic));
167 
168 	n = fread(&h->version, sizeof(h->version), 1, f);
169 	if (n != 1) {
170 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
171 		goto done;
172 	}
173 
174 	if (betoh32(h->version) != GOT_PACKIDX_VERSION) {
175 		err = got_error(GOT_ERR_BAD_PACKIDX);
176 		goto done;
177 	}
178 
179 	SHA1Update(&ctx, (uint8_t *)&h->version, sizeof(h->version));
180 
181 	n = fread(&h->fanout_table, sizeof(h->fanout_table), 1, f);
182 	if (n != 1) {
183 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
184 		goto done;
185 	}
186 
187 	err = verify_fanout_table(h->fanout_table);
188 	if (err)
189 		goto done;
190 
191 	SHA1Update(&ctx, (uint8_t *)h->fanout_table, sizeof(h->fanout_table));
192 
193 	nobj = betoh32(h->fanout_table[0xff]);
194 
195 	h->sorted_ids = calloc(nobj, sizeof(*h->sorted_ids));
196 	if (h->sorted_ids == NULL) {
197 		err = got_error_from_errno();
198 		goto done;
199 	}
200 
201 	n = fread(h->sorted_ids, sizeof(*h->sorted_ids), nobj, f);
202 	if (n != nobj) {
203 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
204 		goto done;
205 	}
206 
207 	SHA1Update(&ctx, (uint8_t *)h->sorted_ids,
208 	    nobj * sizeof(*h->sorted_ids));
209 
210 	h->crc32 = calloc(nobj, sizeof(*h->crc32));
211 	if (h->crc32 == NULL) {
212 		err = got_error_from_errno();
213 		goto done;
214 	}
215 
216 	n = fread(h->crc32, sizeof(*h->crc32), nobj, f);
217 	if (n != nobj) {
218 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
219 		goto done;
220 	}
221 
222 	SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
223 
224 	h->offsets = calloc(nobj, sizeof(*h->offsets));
225 	if (h->offsets == NULL) {
226 		err = got_error_from_errno();
227 		goto done;
228 	}
229 
230 	n = fread(h->offsets, sizeof(*h->offsets), nobj, f);
231 	if (n != nobj) {
232 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
233 		goto done;
234 	}
235 
236 	SHA1Update(&ctx, (uint8_t *)h->offsets, nobj * sizeof(*h->offsets));
237 
238 	/* Large file offsets are contained only in files > 2GB. */
239 	if (packfile_size <= 0x80000000)
240 		goto checksum;
241 
242 	h->large_offsets = calloc(nobj, sizeof(*h->large_offsets));
243 	if (h->large_offsets == NULL) {
244 		err = got_error_from_errno();
245 		goto done;
246 	}
247 
248 	n = fread(h->large_offsets, sizeof(*h->large_offsets), nobj, f);
249 	if (n != nobj) {
250 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
251 		goto done;
252 	}
253 
254 	SHA1Update(&ctx, (uint8_t*)h->large_offsets,
255 	    nobj * sizeof(*h->large_offsets));
256 
257 checksum:
258 	n = fread(&h->trailer, sizeof(h->trailer), 1, f);
259 	if (n != 1) {
260 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
261 		goto done;
262 	}
263 
264 	SHA1Update(&ctx, h->trailer.packfile_sha1, SHA1_DIGEST_LENGTH);
265 	SHA1Final(sha1, &ctx);
266 	if (memcmp(h->trailer.packidx_sha1, sha1, SHA1_DIGEST_LENGTH) != 0)
267 		err = got_error(GOT_ERR_PACKIDX_CSUM);
268 done:
269 	fclose(f);
270 	if (err)
271 		got_packidx_close(p);
272 	else
273 		*packidx = p;
274 	return err;
275 }
276 
277 void
278 got_packidx_close(struct got_packidx *packidx)
279 {
280 	free(packidx->hdr.sorted_ids);
281 	free(packidx->hdr.offsets);
282 	free(packidx->hdr.crc32);
283 	free(packidx->hdr.large_offsets);
284 	free(packidx->path_packidx);
285 	free(packidx);
286 }
287 
288 static int
289 is_packidx_filename(const char *name, size_t len)
290 {
291 	if (len != GOT_PACKIDX_NAMELEN)
292 		return 0;
293 
294 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
295 		return 0;
296 
297 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
298 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
299 		return 0;
300 
301 	return 1;
302 }
303 
304 static off_t
305 get_object_offset(struct got_packidx *packidx, int idx)
306 {
307 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
308 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
309 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
310 		uint64_t loffset;
311 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
312 		if (idx < 0 || idx > totobj ||
313 		    packidx->hdr.large_offsets == NULL)
314 			return -1;
315 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
316 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
317 	}
318 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
319 }
320 
321 static int
322 get_object_idx(struct got_packidx *packidx, struct got_object_id *id,
323     struct got_repository *repo)
324 {
325 	u_int8_t id0 = id->sha1[0];
326 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
327 	int left = 0, right = totobj - 1;
328 
329 	if (id0 > 0)
330 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
331 
332 	while (left <= right) {
333 		struct got_object_id *oid;
334 		int i, cmp;
335 
336 		i = ((left + right) / 2);
337 		oid = &packidx->hdr.sorted_ids[i];
338 		cmp = got_object_id_cmp(id, oid);
339 		if (cmp == 0)
340 			return i;
341 		else if (cmp > 0)
342 			left = i + 1;
343 		else if (cmp < 0)
344 			right = i - 1;
345 	}
346 
347 	return -1;
348 }
349 
350 static struct got_packidx *
351 dup_packidx(struct got_packidx *packidx)
352 {
353 	struct got_packidx *p;
354 	size_t nobj;
355 
356 	p = calloc(1, sizeof(*p));
357 	if (p == NULL)
358 		return NULL;
359 
360 	p->path_packidx = strdup(packidx->path_packidx);
361 	if (p->path_packidx == NULL) {
362 		free(p);
363 		return NULL;
364 	}
365 	memcpy(&p->hdr, &packidx->hdr, sizeof(p->hdr));
366 	p->hdr.sorted_ids = NULL;
367 	p->hdr.crc32 = NULL;
368 	p->hdr.offsets = NULL;
369 	p->hdr.large_offsets = NULL;
370 
371 	nobj = betoh32(p->hdr.fanout_table[0xff]);
372 
373 	p->hdr.sorted_ids = calloc(nobj, sizeof(*p->hdr.sorted_ids));
374 	if (p->hdr.sorted_ids == NULL)
375 		goto err;
376 	memcpy(p->hdr.sorted_ids, packidx->hdr.sorted_ids,
377 	    nobj * sizeof(*p->hdr.sorted_ids));
378 
379 	p->hdr.crc32 = calloc(nobj, sizeof(*p->hdr.crc32));
380 	if (p->hdr.crc32 == NULL)
381 		goto err;
382 	memcpy(p->hdr.crc32, packidx->hdr.crc32, nobj * sizeof(*p->hdr.crc32));
383 
384 	p->hdr.offsets = calloc(nobj, sizeof(*p->hdr.offsets));
385 	if (p->hdr.offsets == NULL)
386 		goto err;
387 	memcpy(p->hdr.offsets, packidx->hdr.offsets,
388 	    nobj * sizeof(*p->hdr.offsets));
389 
390 	if (p->hdr.large_offsets) {
391 		p->hdr.large_offsets = calloc(nobj,
392 		    sizeof(*p->hdr.large_offsets));
393 		if (p->hdr.large_offsets == NULL)
394 			goto err;
395 		memcpy(p->hdr.large_offsets, packidx->hdr.large_offsets,
396 		    nobj * sizeof(*p->hdr.large_offsets));
397 	}
398 
399 	return p;
400 
401 err:
402 	free(p->hdr.large_offsets);
403 	free(p->hdr.offsets);
404 	free(p->hdr.crc32);
405 	free(p->hdr.sorted_ids);
406 	free(p->path_packidx);
407 	free(p);
408 	return NULL;
409 }
410 
411 static void
412 cache_packidx(struct got_packidx *packidx, struct got_repository *repo)
413 {
414 	int i;
415 
416 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
417 		if (repo->packidx_cache[i] == NULL)
418 			break;
419 	}
420 
421 	if (i == nitems(repo->packidx_cache)) {
422 		got_packidx_close(repo->packidx_cache[i - 1]);
423 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
424 		    sizeof(repo->packidx_cache) -
425 		    sizeof(repo->packidx_cache[0]));
426 		i = 0;
427 	}
428 
429 	repo->packidx_cache[i] = dup_packidx(packidx);
430 }
431 
432 static const struct got_error *
433 search_packidx(struct got_packidx **packidx, int *idx,
434     struct got_repository *repo, struct got_object_id *id)
435 {
436 	const struct got_error *err;
437 	char *path_packdir;
438 	DIR *packdir;
439 	struct dirent *dent;
440 	char *path_packidx;
441 	int i;
442 
443 	/* Search pack index cache. */
444 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
445 		if (repo->packidx_cache[i] == NULL)
446 			break;
447 		*idx = get_object_idx(repo->packidx_cache[i], id, repo);
448 		if (*idx != -1) {
449 			*packidx = repo->packidx_cache[i];
450 			return NULL;
451 		}
452 	}
453 	/* No luck. Search the filesystem. */
454 
455 	path_packdir = got_repo_get_path_objects_pack(repo);
456 	if (path_packdir == NULL)
457 		return got_error_from_errno();
458 
459 	packdir = opendir(path_packdir);
460 	if (packdir == NULL) {
461 		err = got_error_from_errno();
462 		goto done;
463 	}
464 
465 	while ((dent = readdir(packdir)) != NULL) {
466 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
467 			continue;
468 
469 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
470 		    dent->d_name) == -1) {
471 			err = got_error_from_errno();
472 			goto done;
473 		}
474 
475 		err = got_packidx_open(packidx, path_packidx);
476 		free(path_packidx);
477 		if (err)
478 			goto done;
479 
480 		*idx = get_object_idx(*packidx, id, repo);
481 		if (*idx != -1) {
482 			err = NULL; /* found the object */
483 			cache_packidx(*packidx, repo);
484 			goto done;
485 		}
486 
487 		got_packidx_close(*packidx);
488 		*packidx = NULL;
489 	}
490 
491 	err = got_error(GOT_ERR_NO_OBJ);
492 done:
493 	free(path_packdir);
494 	if (packdir && closedir(packdir) != 0 && err == 0)
495 		err = got_error_from_errno();
496 	return err;
497 }
498 
499 static const struct got_error *
500 get_packfile_path(char **path_packfile, struct got_repository *repo,
501     struct got_packidx *packidx)
502 {
503 	size_t size;
504 
505 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
506 	size = strlen(packidx->path_packidx) + 2;
507 	if (size < GOT_PACKFILE_NAMELEN + 1)
508 		return got_error(GOT_ERR_BAD_PATH);
509 
510 	*path_packfile = calloc(size, sizeof(**path_packfile));
511 	if (*path_packfile == NULL)
512 		return got_error_from_errno();
513 
514 	/* Copy up to and excluding ".idx". */
515 	if (strlcpy(*path_packfile, packidx->path_packidx,
516 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
517 		return got_error(GOT_ERR_NO_SPACE);
518 
519 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
520 		return got_error(GOT_ERR_NO_SPACE);
521 
522 	return NULL;
523 }
524 
525 const struct got_error *
526 read_packfile_hdr(int fd, struct got_packidx *packidx)
527 {
528 	const struct got_error *err = NULL;
529 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
530 	struct got_packfile_hdr hdr;
531 	ssize_t n;
532 
533 	n = read(fd, &hdr, sizeof(hdr));
534 	if (n < 0)
535 		return got_error_from_errno();
536 	if (n != sizeof(hdr))
537 		return got_error(GOT_ERR_BAD_PACKFILE);
538 
539 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
540 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
541 	    betoh32(hdr.nobjects) != totobj)
542 		err = got_error(GOT_ERR_BAD_PACKFILE);
543 
544 	return err;
545 }
546 
547 static const struct got_error *
548 open_packfile(int *fd, const char *path_packfile,
549     struct got_repository *repo, struct got_packidx *packidx)
550 {
551 	const struct got_error *err = NULL;
552 
553 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
554 	if (*fd == -1)
555 		return got_error_from_errno();
556 
557 	if (packidx) {
558 		err = read_packfile_hdr(*fd, packidx);
559 		if (err) {
560 			close(*fd);
561 			*fd = -1;
562 		}
563 	}
564 	return err;
565 }
566 
567 void
568 got_pack_close(struct got_pack *pack)
569 {
570 	close(pack->fd);
571 	pack->fd = -1;
572 	free(pack->path_packfile);
573 	pack->path_packfile = NULL;
574 	pack->filesize = 0;
575 }
576 
577 static const struct got_error *
578 cache_pack(struct got_pack **packp, const char *path_packfile,
579     struct got_packidx *packidx, struct got_repository *repo)
580 {
581 	const struct got_error *err = NULL;
582 	struct got_pack *pack = NULL;
583 	int i;
584 
585 	if (packp)
586 		*packp = NULL;
587 
588 	for (i = 0; i < nitems(repo->packs); i++) {
589 		pack = &repo->packs[i];
590 		if (pack->path_packfile == NULL)
591 			break;
592 		if (strcmp(pack->path_packfile, path_packfile) == 0)
593 			return NULL;
594 	}
595 
596 	if (i == nitems(repo->packs) - 1) {
597 		got_pack_close(&repo->packs[i - 1]);
598 		memmove(&repo->packs[1], &repo->packs[0],
599 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
600 		i = 0;
601 	}
602 
603 	pack = &repo->packs[i];
604 
605 	pack->path_packfile = strdup(path_packfile);
606 	if (pack->path_packfile == NULL) {
607 		err = got_error_from_errno();
608 		goto done;
609 	}
610 
611 	err = open_packfile(&pack->fd, path_packfile, repo, packidx);
612 	if (err)
613 		goto done;
614 
615 	err = get_packfile_size(&pack->filesize, path_packfile);
616 done:
617 	if (err) {
618 		if (pack) {
619 			free(pack->path_packfile);
620 			memset(pack, 0, sizeof(*pack));
621 		}
622 	} else if (packp)
623 		*packp = pack;
624 	return err;
625 }
626 
627 struct got_pack *
628 get_cached_pack(const char *path_packfile, struct got_repository *repo)
629 {
630 	struct got_pack *pack = NULL;
631 	int i;
632 
633 	for (i = 0; i < nitems(repo->packs); i++) {
634 		pack = &repo->packs[i];
635 		if (pack->path_packfile == NULL)
636 			break;
637 		if (strcmp(pack->path_packfile, path_packfile) == 0)
638 			return pack;
639 	}
640 
641 	return NULL;
642 }
643 
644 static const struct got_error *
645 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len, int fd)
646 {
647 	uint8_t t = 0;
648 	uint64_t s = 0;
649 	uint8_t sizeN;
650 	ssize_t n;
651 	int i = 0;
652 
653 	do {
654 		/* We do not support size values which don't fit in 64 bit. */
655 		if (i > 9)
656 			return got_error(GOT_ERR_NO_SPACE);
657 
658 		n = read(fd, &sizeN, sizeof(sizeN));
659 		if (n < 0)
660 			return got_error_from_errno();
661 		if (n != sizeof(sizeN))
662 			return got_error(GOT_ERR_BAD_PACKFILE);
663 
664 		if (i == 0) {
665 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
666 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
667 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
668 		} else {
669 			size_t shift = 4 + 7 * (i - 1);
670 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
671 		}
672 		i++;
673 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
674 
675 	*type = t;
676 	*size = s;
677 	*len = i * sizeof(sizeN);
678 	return NULL;
679 }
680 
681 static const struct got_error *
682 open_plain_object(struct got_object **obj, const char *path_packfile,
683     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
684 {
685 	*obj = calloc(1, sizeof(**obj));
686 	if (*obj == NULL)
687 		return got_error_from_errno();
688 
689 	(*obj)->path_packfile = strdup(path_packfile);
690 	if ((*obj)->path_packfile == NULL) {
691 		const struct got_error *err = got_error_from_errno();
692 		free(*obj);
693 		*obj = NULL;
694 		return err;
695 	}
696 
697 	(*obj)->type = type;
698 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
699 	(*obj)->hdrlen = 0;
700 	(*obj)->size = size;
701 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
702 	(*obj)->pack_offset = offset;
703 
704 	return NULL;
705 }
706 
707 static const struct got_error *
708 parse_negative_offset(int64_t *offset, size_t *len, int fd)
709 {
710 	int64_t o = 0;
711 	uint8_t offN;
712 	ssize_t n;
713 	int i = 0;
714 
715 	do {
716 		/* We do not support offset values which don't fit in 64 bit. */
717 		if (i > 8)
718 			return got_error(GOT_ERR_NO_SPACE);
719 
720 		n = read(fd, &offN, sizeof(offN));
721 		if (n < 0)
722 			return got_error_from_errno();
723 		if (n != sizeof(offN))
724 			return got_error(GOT_ERR_BAD_PACKFILE);
725 
726 		if (i == 0)
727 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
728 		else {
729 			o++;
730 			o <<= 7;
731 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
732 		}
733 		i++;
734 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
735 
736 	*offset = o;
737 	*len = i * sizeof(offN);
738 	return NULL;
739 }
740 
741 static const struct got_error *
742 parse_offset_delta(off_t *base_offset, int fd, off_t offset)
743 {
744 	const struct got_error *err;
745 	int64_t negoffset;
746 	size_t negofflen;
747 
748 	err = parse_negative_offset(&negoffset, &negofflen, fd);
749 	if (err)
750 		return err;
751 
752 	/* Compute the base object's offset (must be in the same pack file). */
753 	*base_offset = (offset - negoffset);
754 	if (*base_offset <= 0)
755 		return got_error(GOT_ERR_BAD_PACKFILE);
756 
757 	return NULL;
758 }
759 
760 static const struct got_error *
761 resolve_delta_chain(struct got_delta_chain *, struct got_repository *,
762     int, size_t, const char *, off_t, size_t, int, size_t, unsigned int);
763 
764 static const struct got_error *
765 add_delta(struct got_delta_chain *deltas, const char *path_packfile,
766     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
767     size_t delta_data_offset, uint8_t *delta_buf, size_t delta_len)
768 {
769 	struct got_delta *delta;
770 
771 	delta = got_delta_open(path_packfile, delta_offset, tslen,
772 	    delta_type, delta_size, delta_data_offset, delta_buf,
773 	    delta_len);
774 	if (delta == NULL)
775 		return got_error_from_errno();
776 	/* delta is freed in got_object_close() */
777 	deltas->nentries++;
778 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
779 	return NULL;
780 }
781 
782 static const struct got_error *
783 resolve_offset_delta(struct got_delta_chain *deltas,
784     struct got_repository *repo, int fd, size_t packfile_size,
785     const char *path_packfile, off_t delta_offset, size_t tslen,
786     int delta_type, size_t delta_size, unsigned int recursion)
787 
788 {
789 	const struct got_error *err;
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 	err = parse_offset_delta(&base_offset, fd, delta_offset);
799 	if (err)
800 		return err;
801 
802 	delta_data_offset = lseek(fd, 0, SEEK_CUR);
803 	if (delta_data_offset == -1)
804 		return got_error_from_errno();
805 
806 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, fd);
807 	if (err)
808 		return err;
809 
810 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
811 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
812 	if (err)
813 		return err;
814 
815 	/* An offset delta must be in the same packfile. */
816 	if (base_offset >= packfile_size)
817 		return got_error(GOT_ERR_PACK_OFFSET);
818 	if (lseek(fd, base_offset, SEEK_SET) == -1)
819 		return got_error_from_errno();
820 
821 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
822 	    fd);
823 	if (err)
824 		return err;
825 
826 	return resolve_delta_chain(deltas, repo, fd, packfile_size,
827 	    path_packfile, base_offset, base_tslen, base_type, base_size,
828 	    recursion - 1);
829 }
830 
831 static const struct got_error *
832 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
833     int fd, const char *path_packfile, off_t delta_offset,
834     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
835 {
836 	const struct got_error *err;
837 	struct got_object_id id;
838 	struct got_packidx *packidx;
839 	int idx;
840 	off_t base_offset;
841 	uint8_t base_type;
842 	uint64_t base_size;
843 	size_t base_tslen;
844 	ssize_t n;
845 	char *path_base_packfile;
846 	struct got_pack *base_pack;
847 	off_t delta_data_offset;
848 	uint8_t *delta_buf;
849 	size_t delta_len;
850 
851 	n = read(fd, &id, sizeof(id));
852 	if (n < 0)
853 		return got_error_from_errno();
854 	if (n != sizeof(id))
855 		return got_error(GOT_ERR_BAD_PACKFILE);
856 
857 	delta_data_offset = lseek(fd, 0, SEEK_CUR);
858 	if (delta_data_offset == -1)
859 		return got_error_from_errno();
860 
861 	err = got_inflate_to_mem_fd(&delta_buf, &delta_len, fd);
862 	if (err)
863 		return err;
864 
865 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
866 	    delta_type, delta_size, delta_data_offset, delta_buf, delta_len);
867 	if (err)
868 		return err;
869 
870 	err = search_packidx(&packidx, &idx, repo, &id);
871 	if (err)
872 		return err;
873 
874 	base_offset = get_object_offset(packidx, idx);
875 	if (base_offset == (uint64_t)-1) {
876 		return got_error(GOT_ERR_BAD_PACKIDX);
877 	}
878 
879 	err = get_packfile_path(&path_base_packfile, repo, packidx);
880 	if (err)
881 		return err;
882 
883 	base_pack = get_cached_pack(path_base_packfile, repo);
884 	if (base_pack == NULL) {
885 		err = cache_pack(&base_pack, path_base_packfile, NULL, repo);
886 		if (err)
887 			goto done;
888 	}
889 
890 	if (base_offset >= base_pack->filesize) {
891 		err = got_error(GOT_ERR_PACK_OFFSET);
892 		goto done;
893 	}
894 	if (lseek(base_pack->fd, base_offset, SEEK_SET) == -1) {
895 		err = got_error_from_errno();
896 		goto done;
897 	}
898 
899 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
900 	    base_pack->fd);
901 	if (err)
902 		goto done;
903 
904 	err = resolve_delta_chain(deltas, repo, base_pack->fd,
905 	    base_pack->filesize, path_base_packfile, base_offset,
906 	    base_tslen, base_type, base_size, recursion - 1);
907 done:
908 	free(path_base_packfile);
909 	return err;
910 }
911 
912 static const struct got_error *
913 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
914     int fd, size_t packfile_size, const char *path_packfile, off_t delta_offset,
915     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
916 {
917 	const struct got_error *err = NULL;
918 
919 	if (--recursion == 0)
920 		return got_error(GOT_ERR_RECURSION);
921 
922 	switch (delta_type) {
923 	case GOT_OBJ_TYPE_COMMIT:
924 	case GOT_OBJ_TYPE_TREE:
925 	case GOT_OBJ_TYPE_BLOB:
926 	case GOT_OBJ_TYPE_TAG:
927 		/* Plain types are the final delta base. Recursion ends. */
928 		err = add_delta(deltas, path_packfile, delta_offset, tslen,
929 		    delta_type, delta_size, 0, NULL, 0);
930 		break;
931 	case GOT_OBJ_TYPE_OFFSET_DELTA:
932 		err = resolve_offset_delta(deltas, repo, fd, packfile_size,
933 		    path_packfile, delta_offset, tslen, delta_type, delta_size,
934 		    recursion - 1);
935 		break;
936 	case GOT_OBJ_TYPE_REF_DELTA:
937 		err = resolve_ref_delta(deltas, repo, fd, path_packfile,
938 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
939 		break;
940 	default:
941 		return got_error(GOT_ERR_OBJ_TYPE);
942 	}
943 
944 	return err;
945 }
946 
947 static const struct got_error *
948 open_delta_object(struct got_object **obj, struct got_repository *repo,
949     const char *path_packfile, int fd, size_t packfile_size,
950     struct got_object_id *id, off_t offset, size_t tslen,
951     int delta_type, size_t delta_size)
952 {
953 	const struct got_error *err = NULL;
954 	int resolved_type;
955 
956 	*obj = calloc(1, sizeof(**obj));
957 	if (*obj == NULL)
958 		return got_error_from_errno();
959 
960 	(*obj)->flags = 0;
961 	(*obj)->hdrlen = 0;
962 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
963 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
964 	(*obj)->pack_offset = offset + tslen;
965 
966 	(*obj)->path_packfile = strdup(path_packfile);
967 	if ((*obj)->path_packfile == NULL) {
968 		err = got_error_from_errno();
969 		goto done;
970 	}
971 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
972 
973 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
974 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
975 
976 	err = resolve_delta_chain(&(*obj)->deltas, repo, fd, packfile_size,
977 	    path_packfile, offset, tslen, delta_type, delta_size,
978 	    GOT_DELTA_CHAIN_RECURSION_MAX);
979 	if (err)
980 		goto done;
981 
982 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
983 	if (err)
984 		goto done;
985 	(*obj)->type = resolved_type;
986 
987 done:
988 	if (err) {
989 		got_object_close(*obj);
990 		*obj = NULL;
991 	}
992 	return err;
993 }
994 
995 static const struct got_error *
996 open_packed_object(struct got_object **obj, struct got_repository *repo,
997     struct got_packidx *packidx, int idx, struct got_object_id *id)
998 {
999 	const struct got_error *err = NULL;
1000 	off_t offset;
1001 	char *path_packfile;
1002 	struct got_pack *pack;
1003 	uint8_t type;
1004 	uint64_t size;
1005 	size_t tslen;
1006 
1007 	*obj = NULL;
1008 
1009 	offset = get_object_offset(packidx, idx);
1010 	if (offset == (uint64_t)-1)
1011 		return got_error(GOT_ERR_BAD_PACKIDX);
1012 
1013 	err = get_packfile_path(&path_packfile, repo, packidx);
1014 	if (err)
1015 		return err;
1016 
1017 	pack = get_cached_pack(path_packfile, repo);
1018 	if (pack == NULL) {
1019 		err = cache_pack(&pack, path_packfile, packidx, repo);
1020 		if (err)
1021 			goto done;
1022 	}
1023 
1024 	if (offset >= pack->filesize) {
1025 		err = got_error(GOT_ERR_PACK_OFFSET);
1026 		goto done;
1027 	}
1028 	if (lseek(pack->fd, offset, SEEK_SET) == -1) {
1029 		err = got_error_from_errno();
1030 		goto done;
1031 	}
1032 
1033 	err = parse_object_type_and_size(&type, &size, &tslen, pack->fd);
1034 	if (err)
1035 		goto done;
1036 
1037 	switch (type) {
1038 	case GOT_OBJ_TYPE_COMMIT:
1039 	case GOT_OBJ_TYPE_TREE:
1040 	case GOT_OBJ_TYPE_BLOB:
1041 	case GOT_OBJ_TYPE_TAG:
1042 		err = open_plain_object(obj, path_packfile, id, type,
1043 		    offset + tslen, size);
1044 		break;
1045 
1046 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1047 	case GOT_OBJ_TYPE_REF_DELTA:
1048 		err = open_delta_object(obj, repo, path_packfile, pack->fd,
1049 		    pack->filesize, id, offset, tslen, type, size);
1050 		break;
1051 
1052 	default:
1053 		err = got_error(GOT_ERR_OBJ_TYPE);
1054 		goto done;
1055 	}
1056 done:
1057 	free(path_packfile);
1058 	return err;
1059 }
1060 
1061 const struct got_error *
1062 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1063     struct got_repository *repo)
1064 {
1065 	const struct got_error *err = NULL;
1066 	struct got_packidx *packidx = NULL;
1067 	int idx;
1068 
1069 	err = search_packidx(&packidx, &idx, repo, id);
1070 	if (err)
1071 		return err;
1072 
1073 	err = open_packed_object(obj, repo, packidx, idx, id);
1074 	if (err)
1075 		return err;
1076 
1077 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1078 	return err;
1079 }
1080 
1081 static const struct got_error *
1082 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1083 {
1084 	struct got_delta *delta;
1085 	uint64_t base_size = 0, result_size = 0;
1086 
1087 	*max_size = 0;
1088 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1089 		/* Plain object types are the delta base. */
1090 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1091 		    delta->type != GOT_OBJ_TYPE_TREE &&
1092 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1093 		    delta->type != GOT_OBJ_TYPE_TAG) {
1094 			const struct got_error *err;
1095 			err = got_delta_get_sizes(&base_size, &result_size,
1096 			    delta->delta_buf, delta->delta_len);
1097 			if (err)
1098 				return err;
1099 		} else
1100 			base_size = delta->size;
1101 		if (base_size > *max_size)
1102 			*max_size = base_size;
1103 		if (result_size > *max_size)
1104 			*max_size = result_size;
1105 	}
1106 
1107 	return NULL;
1108 }
1109 
1110 static const struct got_error *
1111 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1112     FILE *outfile, struct got_repository *repo)
1113 {
1114 	const struct got_error *err = NULL;
1115 	struct got_delta *delta;
1116 	FILE *base_file = NULL, *accum_file = NULL;
1117 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1118 	size_t accum_size = 0;
1119 	uint64_t max_size;
1120 	int n = 0;
1121 
1122 	*result_size = 0;
1123 
1124 	if (SIMPLEQ_EMPTY(&deltas->entries))
1125 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1126 
1127 	/* We process small enough files entirely in memory for speed. */
1128 	err = get_delta_chain_max_size(&max_size, deltas);
1129 	if (err)
1130 		return err;
1131 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1132 		accum_buf = malloc(max_size);
1133 		if (accum_buf == NULL)
1134 			return got_error_from_errno();
1135 	} else {
1136 		base_file = got_opentemp();
1137 		if (base_file == NULL)
1138 			return got_error_from_errno();
1139 
1140 		accum_file = got_opentemp();
1141 		if (accum_file == NULL) {
1142 			err = got_error_from_errno();
1143 			fclose(base_file);
1144 			return err;
1145 		}
1146 	}
1147 
1148 	/* Deltas are ordered in ascending order. */
1149 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1150 		if (n == 0) {
1151 			struct got_pack *pack;
1152 			size_t base_len;
1153 			off_t delta_data_offset;
1154 
1155 			/* Plain object types are the delta base. */
1156 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1157 			    delta->type != GOT_OBJ_TYPE_TREE &&
1158 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1159 			    delta->type != GOT_OBJ_TYPE_TAG) {
1160 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1161 				goto done;
1162 			}
1163 
1164 			pack = get_cached_pack(delta->path_packfile, repo);
1165 			if (pack == NULL) {
1166 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1167 				goto done;
1168 			}
1169 
1170 			delta_data_offset = delta->offset + delta->tslen;
1171 			if (delta_data_offset >= pack->filesize) {
1172 				err = got_error(GOT_ERR_PACK_OFFSET);
1173 				goto done;
1174 			}
1175 			if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1176 				err = got_error_from_errno();
1177 				goto done;
1178 			}
1179 			if (base_file)
1180 				err = got_inflate_to_file_fd(&base_len,
1181 				    pack->fd, base_file);
1182 			else {
1183 				err = got_inflate_to_mem_fd(&base_buf,
1184 				    &base_len, pack->fd);
1185 				if (base_len < max_size) {
1186 					uint8_t *p;
1187 					p = reallocarray(base_buf, 1, max_size);
1188 					if (p == NULL) {
1189 						err = got_error_from_errno();
1190 						goto done;
1191 					}
1192 					base_buf = p;
1193 				}
1194 			}
1195 			if (err)
1196 				goto done;
1197 			n++;
1198 			if (base_file)
1199 				rewind(base_file);
1200 			continue;
1201 		}
1202 
1203 		if (base_buf) {
1204 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1205 			    delta->delta_len, accum_buf, &accum_size);
1206 			n++;
1207 		} else {
1208 			err = got_delta_apply(base_file, delta->delta_buf,
1209 			    delta->delta_len,
1210 			    /* Final delta application writes to output file. */
1211 			    ++n < deltas->nentries ? accum_file : outfile,
1212 			    &accum_size);
1213 		}
1214 		if (err)
1215 			goto done;
1216 
1217 		if (n < deltas->nentries) {
1218 			/* Accumulated delta becomes the new base. */
1219 			if (base_buf) {
1220 				uint8_t *tmp = accum_buf;
1221 				accum_buf = base_buf;
1222 				base_buf = tmp;
1223 			} else {
1224 				FILE *tmp = accum_file;
1225 				accum_file = base_file;
1226 				base_file = tmp;
1227 				rewind(base_file);
1228 				rewind(accum_file);
1229 			}
1230 		}
1231 	}
1232 
1233 done:
1234 	free(base_buf);
1235 	if (accum_buf) {
1236 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1237 		free(accum_buf);
1238 		if (len != accum_size)
1239 			return got_ferror(outfile, GOT_ERR_IO);
1240 	}
1241 	if (base_file)
1242 		fclose(base_file);
1243 	if (accum_file)
1244 		fclose(accum_file);
1245 	rewind(outfile);
1246 	if (err == NULL)
1247 		*result_size = accum_size;
1248 	return err;
1249 }
1250 
1251 static const struct got_error *
1252 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1253     struct got_delta_chain *deltas, struct got_repository *repo)
1254 {
1255 	const struct got_error *err = NULL;
1256 	struct got_delta *delta;
1257 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1258 	size_t accum_size;
1259 	uint64_t max_size;
1260 	int n = 0;
1261 
1262 	*outbuf = NULL;
1263 	*outlen = 0;
1264 
1265 	if (SIMPLEQ_EMPTY(&deltas->entries))
1266 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1267 
1268 	err = get_delta_chain_max_size(&max_size, deltas);
1269 	if (err)
1270 		return err;
1271 	accum_buf = malloc(max_size);
1272 	if (accum_buf == NULL)
1273 		return got_error_from_errno();
1274 
1275 	/* Deltas are ordered in ascending order. */
1276 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1277 		if (n == 0) {
1278 			struct got_pack *pack;
1279 			size_t base_len;
1280 			size_t delta_data_offset;
1281 
1282 			/* Plain object types are the delta base. */
1283 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1284 			    delta->type != GOT_OBJ_TYPE_TREE &&
1285 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1286 			    delta->type != GOT_OBJ_TYPE_TAG) {
1287 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1288 				goto done;
1289 			}
1290 
1291 			pack = get_cached_pack(delta->path_packfile, repo);
1292 			if (pack == NULL) {
1293 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1294 				goto done;
1295 			}
1296 
1297 			delta_data_offset = delta->offset + delta->tslen;
1298 			if (delta_data_offset >= pack->filesize) {
1299 				err = got_error(GOT_ERR_PACK_OFFSET);
1300 				goto done;
1301 			}
1302 			if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1303 				err = got_error_from_errno();
1304 				goto done;
1305 			}
1306 			err = got_inflate_to_mem_fd(&base_buf, &base_len,
1307 			    pack->fd);
1308 			if (base_len < max_size) {
1309 				uint8_t *p;
1310 				p = reallocarray(base_buf, 1, max_size);
1311 				if (p == NULL) {
1312 					err = got_error_from_errno();
1313 					goto done;
1314 				}
1315 				base_buf = p;
1316 			}
1317 			if (err)
1318 				goto done;
1319 			n++;
1320 			continue;
1321 		}
1322 
1323 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1324 		    delta->delta_len, accum_buf, &accum_size);
1325 		n++;
1326 		if (err)
1327 			goto done;
1328 
1329 		if (n < deltas->nentries) {
1330 			/* Accumulated delta becomes the new base. */
1331 			uint8_t *tmp = accum_buf;
1332 			accum_buf = base_buf;
1333 			base_buf = tmp;
1334 		}
1335 	}
1336 
1337 done:
1338 	free(base_buf);
1339 	if (err) {
1340 		free(accum_buf);
1341 		*outbuf = NULL;
1342 		*outlen = 0;
1343 	} else {
1344 		*outbuf = accum_buf;
1345 		*outlen = accum_size;
1346 	}
1347 	return err;
1348 }
1349 
1350 const struct got_error *
1351 got_packfile_extract_object(FILE **f, struct got_object *obj,
1352     struct got_repository *repo)
1353 {
1354 	const struct got_error *err = NULL;
1355 
1356 	*f = NULL;
1357 
1358 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1359 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1360 
1361 	*f = got_opentemp();
1362 	if (*f == NULL) {
1363 		err = got_error_from_errno();
1364 		goto done;
1365 	}
1366 
1367 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1368 		struct got_pack *pack;
1369 
1370 		pack = get_cached_pack(obj->path_packfile, repo);
1371 		if (pack == NULL) {
1372 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1373 			if (err)
1374 				goto done;
1375 		}
1376 
1377 		if (obj->pack_offset >= pack->filesize) {
1378 			err = got_error(GOT_ERR_PACK_OFFSET);
1379 			goto done;
1380 		}
1381 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1382 			err = got_error_from_errno();
1383 			goto done;
1384 		}
1385 
1386 		err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1387 	} else
1388 		err = dump_delta_chain_to_file(&obj->size,
1389 		    &obj->deltas, *f, repo);
1390 done:
1391 	if (err && *f) {
1392 		fclose(*f);
1393 		*f = NULL;
1394 	}
1395 	return err;
1396 }
1397 
1398 const struct got_error *
1399 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1400     struct got_object *obj, struct got_repository *repo)
1401 {
1402 	const struct got_error *err = NULL;
1403 
1404 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1405 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1406 
1407 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1408 		struct got_pack *pack;
1409 
1410 		pack = get_cached_pack(obj->path_packfile, repo);
1411 		if (pack == NULL) {
1412 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1413 			if (err)
1414 				goto done;
1415 		}
1416 
1417 		if (obj->pack_offset >= pack->filesize) {
1418 			err = got_error(GOT_ERR_PACK_OFFSET);
1419 			goto done;
1420 		}
1421 		if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1422 			err = got_error_from_errno();
1423 			goto done;
1424 		}
1425 
1426 		err = got_inflate_to_mem_fd(buf, len, pack->fd);
1427 	} else
1428 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, repo);
1429 done:
1430 	return err;
1431 }