1 /*
2  * Copyright (c) 2018, 2019, 2020 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 #include <sys/resource.h>
23 #include <sys/socket.h>
24 
25 #include <fcntl.h>
26 #include <errno.h>
27 #include <stdio.h>
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <limits.h>
32 #include <sha1.h>
33 #include <sha2.h>
34 #include <endian.h>
35 #include <unistd.h>
36 #include <zlib.h>
37 #include <imsg.h>
38 
39 #include "got_error.h"
40 #include "got_object.h"
41 #include "got_path.h"
42 
43 #include "got_lib_hash.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_delta_cache.h"
46 #include "got_lib_inflate.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_parse.h"
49 #include "got_lib_privsep.h"
50 #include "got_lib_pack.h"
51 
52 #ifndef nitems
53 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
54 #endif
55 
56 #ifndef MIN
57 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
58 #endif
59 
60 static inline void
61 hash_init(SHA1_CTX *sha1_ctx, SHA2_CTX *sha256_ctx,
62     enum got_hash_algorithm algo)
63 {
64 	if (algo == GOT_HASH_SHA256)
65 		SHA256Init(sha256_ctx);
66 	else
67 		SHA1Init(sha1_ctx);
68 }
69 
70 static inline void
71 hash_update(SHA1_CTX *sha1_ctx, SHA2_CTX *sha256_ctx, void *data, size_t len,
72     enum got_hash_algorithm algo)
73 {
74 	if (algo == GOT_HASH_SHA256)
75 		SHA256Update(sha256_ctx, data, len);
76 	else
77 		SHA1Update(sha1_ctx, data, len);
78 }
79 
80 static inline void
81 hash_final(SHA1_CTX *sha1_ctx, SHA2_CTX *sha256_ctx, uint8_t *out,
82     enum got_hash_algorithm algo)
83 {
84 	if (algo == GOT_HASH_SHA256)
85 		SHA256Final(out, sha256_ctx);
86 	else
87 		SHA1Final(out, sha1_ctx);
88 }
89 
90 static inline int
91 hash_cmp(uint8_t *orig, uint8_t *comp, enum got_hash_algorithm algo)
92 {
93 	size_t len = SHA1_DIGEST_LENGTH;
94 
95 	if (algo == GOT_HASH_SHA256)
96 		len = SHA256_DIGEST_LENGTH;
97 
98 	return memcmp(orig, comp, len);
99 }
100 
101 static const struct got_error *
102 verify_fanout_table(uint32_t *fanout_table)
103 {
104 	int i;
105 
106 	for (i = 0; i < 0xff - 1; i++) {
107 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
108 			return got_error(GOT_ERR_BAD_PACKIDX);
109 	}
110 
111 	return NULL;
112 }
113 
114 const struct got_error *
115 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size,
116     enum got_hash_algorithm algo)
117 {
118 	const struct got_error *err = NULL;
119 	struct got_packidx_v2_hdr *h;
120 	SHA2_CTX sha256_ctx;
121 	SHA1_CTX sha1_ctx;
122 	uint8_t hash[SHA256_DIGEST_LENGTH];
123 	size_t nobj, len_fanout, len_ids, offset, remain;
124 	ssize_t n;
125 	int i;
126 
127 	hash_init(&sha1_ctx, &sha256_ctx, algo);
128 
129 	h = &p->hdr;
130 	offset = 0;
131 	remain = p->len;
132 
133 	if (remain < sizeof(*h->magic)) {
134 		err = got_error(GOT_ERR_BAD_PACKIDX);
135 		goto done;
136 	}
137 	if (p->map)
138 		h->magic = (uint32_t *)(p->map + offset);
139 	else {
140 		h->magic = malloc(sizeof(*h->magic));
141 		if (h->magic == NULL) {
142 			err = got_error_from_errno("malloc");
143 			goto done;
144 		}
145 		n = read(p->fd, h->magic, sizeof(*h->magic));
146 		if (n < 0) {
147 			err = got_error_from_errno("read");
148 			goto done;
149 		} else if (n != sizeof(*h->magic)) {
150 			err = got_error(GOT_ERR_BAD_PACKIDX);
151 			goto done;
152 		}
153 	}
154 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
155 		err = got_error(GOT_ERR_BAD_PACKIDX);
156 		goto done;
157 	}
158 	offset += sizeof(*h->magic);
159 	remain -= sizeof(*h->magic);
160 
161 	if (verify)
162 		hash_update(&sha1_ctx, &sha256_ctx, h->magic, sizeof(*h->magic),
163 		    algo);
164 
165 	if (remain < sizeof(*h->version)) {
166 		err = got_error(GOT_ERR_BAD_PACKIDX);
167 		goto done;
168 	}
169 	if (p->map)
170 		h->version = (uint32_t *)(p->map + offset);
171 	else {
172 		h->version = malloc(sizeof(*h->version));
173 		if (h->version == NULL) {
174 			err = got_error_from_errno("malloc");
175 			goto done;
176 		}
177 		n = read(p->fd, h->version, sizeof(*h->version));
178 		if (n < 0) {
179 			err = got_error_from_errno("read");
180 			goto done;
181 		} else if (n != sizeof(*h->version)) {
182 			err = got_error(GOT_ERR_BAD_PACKIDX);
183 			goto done;
184 		}
185 	}
186 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
187 		err = got_error(GOT_ERR_BAD_PACKIDX);
188 		goto done;
189 	}
190 	offset += sizeof(*h->version);
191 	remain -= sizeof(*h->version);
192 
193 	if (verify)
194 		hash_update(&sha1_ctx, &sha256_ctx,
195 		    h->version, sizeof(*h->version), algo);
196 
197 	len_fanout =
198 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
199 	if (remain < len_fanout) {
200 		err = got_error(GOT_ERR_BAD_PACKIDX);
201 		goto done;
202 	}
203 	if (p->map)
204 		h->fanout_table = (uint32_t *)(p->map + offset);
205 	else {
206 		h->fanout_table = malloc(len_fanout);
207 		if (h->fanout_table == NULL) {
208 			err = got_error_from_errno("malloc");
209 			goto done;
210 		}
211 		n = read(p->fd, h->fanout_table, len_fanout);
212 		if (n < 0) {
213 			err = got_error_from_errno("read");
214 			goto done;
215 		} else if (n != len_fanout) {
216 			err = got_error(GOT_ERR_BAD_PACKIDX);
217 			goto done;
218 		}
219 	}
220 	err = verify_fanout_table(h->fanout_table);
221 	if (err)
222 		goto done;
223 	if (verify)
224 		hash_update(&sha1_ctx, &sha256_ctx, h->fanout_table,
225 		    len_fanout, algo);
226 	offset += len_fanout;
227 	remain -= len_fanout;
228 
229 	nobj = be32toh(h->fanout_table[0xff]);
230 	len_ids = nobj * sizeof(*h->sorted_ids);
231 	if (len_ids <= nobj || len_ids > remain) {
232 		err = got_error(GOT_ERR_BAD_PACKIDX);
233 		goto done;
234 	}
235 	if (p->map)
236 		h->sorted_ids =
237 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
238 	else {
239 		h->sorted_ids = malloc(len_ids);
240 		if (h->sorted_ids == NULL) {
241 			err = got_error(GOT_ERR_BAD_PACKIDX);
242 			goto done;
243 		}
244 		n = read(p->fd, h->sorted_ids, len_ids);
245 		if (n < 0)
246 			err = got_error_from_errno("read");
247 		else if (n != len_ids) {
248 			err = got_error(GOT_ERR_BAD_PACKIDX);
249 			goto done;
250 		}
251 	}
252 	if (verify)
253 		hash_update(&sha1_ctx, &sha256_ctx, h->sorted_ids, len_ids,
254 		    algo);
255 	offset += len_ids;
256 	remain -= len_ids;
257 
258 	if (remain < nobj * sizeof(*h->crc32)) {
259 		err = got_error(GOT_ERR_BAD_PACKIDX);
260 		goto done;
261 	}
262 	if (p->map)
263 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
264 	else {
265 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
266 		if (h->crc32 == NULL) {
267 			err = got_error_from_errno("malloc");
268 			goto done;
269 		}
270 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
271 		if (n < 0)
272 			err = got_error_from_errno("read");
273 		else if (n != nobj * sizeof(*h->crc32)) {
274 			err = got_error(GOT_ERR_BAD_PACKIDX);
275 			goto done;
276 		}
277 	}
278 	if (verify)
279 		hash_update(&sha1_ctx, &sha256_ctx, h->crc32,
280 		    nobj * sizeof(*h->crc32), algo);
281 	remain -= nobj * sizeof(*h->crc32);
282 	offset += nobj * sizeof(*h->crc32);
283 
284 	if (remain < nobj * sizeof(*h->offsets)) {
285 		err = got_error(GOT_ERR_BAD_PACKIDX);
286 		goto done;
287 	}
288 	if (p->map)
289 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
290 	else {
291 		h->offsets = malloc(nobj * sizeof(*h->offsets));
292 		if (h->offsets == NULL) {
293 			err = got_error_from_errno("malloc");
294 			goto done;
295 		}
296 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
297 		if (n < 0)
298 			err = got_error_from_errno("read");
299 		else if (n != nobj * sizeof(*h->offsets)) {
300 			err = got_error(GOT_ERR_BAD_PACKIDX);
301 			goto done;
302 		}
303 	}
304 	if (verify)
305 		hash_update(&sha1_ctx, &sha256_ctx, h->offsets,
306 		    nobj * sizeof(*h->offsets), algo);
307 	remain -= nobj * sizeof(*h->offsets);
308 	offset += nobj * sizeof(*h->offsets);
309 
310 	/* Large file offsets are contained only in files > 2GB. */
311 	if (verify || packfile_size > 0x7fffffff) {
312 		for (i = 0; i < nobj; i++) {
313 			uint32_t o = h->offsets[i];
314 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
315 				p->nlargeobj++;
316 		}
317 	}
318 	if (p->nlargeobj == 0)
319 		goto checksum;
320 	else if (packfile_size <= 0x7fffffff) {
321 		err = got_error(GOT_ERR_BAD_PACKIDX);
322 		goto done;
323 	}
324 
325 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
326 		err = got_error(GOT_ERR_BAD_PACKIDX);
327 		goto done;
328 	}
329 	if (p->map)
330 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
331 	else {
332 		h->large_offsets = malloc(p->nlargeobj *
333 		    sizeof(*h->large_offsets));
334 		if (h->large_offsets == NULL) {
335 			err = got_error_from_errno("malloc");
336 			goto done;
337 		}
338 		n = read(p->fd, h->large_offsets,
339 		    p->nlargeobj * sizeof(*h->large_offsets));
340 		if (n < 0)
341 			err = got_error_from_errno("read");
342 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
343 			err = got_error(GOT_ERR_BAD_PACKIDX);
344 			goto done;
345 		}
346 	}
347 	if (verify)
348 		hash_update(&sha1_ctx, &sha256_ctx, h->large_offsets,
349 		    p->nlargeobj * sizeof(*h->large_offsets), algo);
350 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
351 	offset += p->nlargeobj * sizeof(*h->large_offsets);
352 
353 checksum:
354 	if (remain < sizeof(*h->trailer)) {
355 		err = got_error(GOT_ERR_BAD_PACKIDX);
356 		goto done;
357 	}
358 	if (p->map)
359 		h->trailer =
360 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
361 	else {
362 		h->trailer = malloc(sizeof(*h->trailer));
363 		if (h->trailer == NULL) {
364 			err = got_error_from_errno("malloc");
365 			goto done;
366 		}
367 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
368 		if (n < 0)
369 			err = got_error_from_errno("read");
370 		else if (n != sizeof(*h->trailer)) {
371 			err = got_error(GOT_ERR_BAD_PACKIDX);
372 			goto done;
373 		}
374 	}
375 	if (verify) {
376 		hash_update(&sha1_ctx, &sha256_ctx, h->trailer->packfile_hash,
377 		    algo == GOT_HASH_SHA256
378 		    ? SHA256_DIGEST_LENGTH
379 		    : SHA1_DIGEST_LENGTH,
380 		    algo);
381 		hash_final(&sha1_ctx, &sha256_ctx, hash, algo);
382 		if (hash_cmp(h->trailer->packidx_hash, hash, algo) != 0)
383 			err = got_error(GOT_ERR_PACKIDX_CSUM);
384 	}
385 done:
386 	return err;
387 }
388 
389 const struct got_error *
390 got_packidx_open(struct got_packidx **packidx,
391     int dir_fd, const char *relpath, int verify, enum got_hash_algorithm algo)
392 {
393 	const struct got_error *err = NULL;
394 	struct got_packidx *p = NULL;
395 	char *pack_relpath;
396 	struct stat idx_sb, pack_sb;
397 
398 	*packidx = NULL;
399 
400 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
401 	if (err)
402 		return err;
403 
404 	/*
405 	 * Ensure that a corresponding pack file exists.
406 	 * Some Git repositories have this problem. Git seems to ignore
407 	 * the existence of lonely pack index files but we do not.
408 	 */
409 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
410 		if (errno == ENOENT) {
411 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
412 			    "%s", relpath);
413 		} else
414 			err = got_error_from_errno2("fstatat", pack_relpath);
415 		goto done;
416 	}
417 
418 	p = calloc(1, sizeof(*p));
419 	if (p == NULL) {
420 		err = got_error_from_errno("calloc");
421 		goto done;
422 	}
423 
424 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
425 	if (p->fd == -1) {
426 		err = got_error_from_errno2("openat", relpath);
427 		goto done;
428 	}
429 
430 	if (fstat(p->fd, &idx_sb) != 0) {
431 		err = got_error_from_errno2("fstat", relpath);
432 		goto done;
433 	}
434 	p->len = idx_sb.st_size;
435 	if (p->len < sizeof(p->hdr)) {
436 		err = got_error(GOT_ERR_BAD_PACKIDX);
437 		goto done;
438 	}
439 
440 	p->path_packidx = strdup(relpath);
441 	if (p->path_packidx == NULL) {
442 		err = got_error_from_errno("strdup");
443 		goto done;
444 	}
445 
446 #ifndef GOT_PACK_NO_MMAP
447 	if (p->len > 0 && p->len <= SIZE_MAX) {
448 		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
449 		if (p->map == MAP_FAILED) {
450 			if (errno != ENOMEM) {
451 				err = got_error_from_errno("mmap");
452 				goto done;
453 			}
454 			p->map = NULL; /* fall back to read(2) */
455 		}
456 	}
457 #endif
458 
459 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size, algo);
460 done:
461 	if (err) {
462 		if (p)
463 			got_packidx_close(p);
464 	} else
465 		*packidx = p;
466 	free(pack_relpath);
467 	return err;
468 }
469 
470 const struct got_error *
471 got_packidx_close(struct got_packidx *packidx)
472 {
473 	const struct got_error *err = NULL;
474 
475 	free(packidx->path_packidx);
476 	if (packidx->map) {
477 		if (munmap(packidx->map, packidx->len) == -1)
478 			err = got_error_from_errno("munmap");
479 	} else {
480 		free(packidx->hdr.magic);
481 		free(packidx->hdr.version);
482 		free(packidx->hdr.fanout_table);
483 		free(packidx->hdr.sorted_ids);
484 		free(packidx->hdr.crc32);
485 		free(packidx->hdr.offsets);
486 		free(packidx->hdr.large_offsets);
487 		free(packidx->hdr.trailer);
488 	}
489 	if (close(packidx->fd) == -1 && err == NULL)
490 		err = got_error_from_errno("close");
491 	free(packidx->sorted_offsets);
492 	free(packidx->sorted_large_offsets);
493 	free(packidx);
494 
495 	return err;
496 }
497 
498 const struct got_error *
499 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
500 {
501 	size_t size;
502 
503 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
504 	size = strlen(path_packidx) + 2;
505 	if (size < GOT_PACKFILE_NAMELEN + 1)
506 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
507 
508 	*path_packfile = malloc(size);
509 	if (*path_packfile == NULL)
510 		return got_error_from_errno("malloc");
511 
512 	/* Copy up to and excluding ".idx". */
513 	if (strlcpy(*path_packfile, path_packidx,
514 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
515 		return got_error(GOT_ERR_NO_SPACE);
516 
517 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
518 		return got_error(GOT_ERR_NO_SPACE);
519 
520 	return NULL;
521 }
522 
523 off_t
524 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
525 {
526 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
527 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
528 		uint64_t loffset;
529 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
530 		if (idx < 0 || idx >= packidx->nlargeobj ||
531 		    packidx->hdr.large_offsets == NULL)
532 			return -1;
533 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
534 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
535 	}
536 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
537 }
538 
539 int
540 got_packidx_get_object_idx(struct got_packidx *packidx,
541     struct got_object_id *id)
542 {
543 	size_t len = SHA1_DIGEST_LENGTH;
544 	u_int8_t id0 = id->hash[0];
545 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
546 	int left = 0, right = totobj - 1;
547 
548 	if (id->algo == GOT_HASH_SHA256)
549 		len = SHA256_DIGEST_LENGTH;
550 
551 	if (id0 > 0)
552 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
553 
554 	while (left <= right) {
555 		struct got_packidx_object_id *oid;
556 		int i, cmp;
557 
558 		i = ((left + right) / 2);
559 		oid = &packidx->hdr.sorted_ids[i];
560 		cmp = memcmp(id->hash, oid->hash, len);
561 		if (cmp == 0)
562 			return i;
563 		else if (cmp > 0)
564 			left = i + 1;
565 		else if (cmp < 0)
566 			right = i - 1;
567 	}
568 
569 	return -1;
570 }
571 
572 static int
573 offset_cmp(const void *pa, const void *pb)
574 {
575 	const struct got_pack_offset_index *a, *b;
576 
577 	a = (const struct got_pack_offset_index *)pa;
578 	b = (const struct got_pack_offset_index *)pb;
579 
580 	if (a->offset < b->offset)
581 		return -1;
582 	else if (a->offset > b->offset)
583 		return 1;
584 
585 	return 0;
586 }
587 
588 static int
589 large_offset_cmp(const void *pa, const void *pb)
590 {
591 	const struct got_pack_large_offset_index *a, *b;
592 
593 	a = (const struct got_pack_large_offset_index *)pa;
594 	b = (const struct got_pack_large_offset_index *)pb;
595 
596 	if (a->offset < b->offset)
597 		return -1;
598 	else if (a->offset > b->offset)
599 		return 1;
600 
601 	return 0;
602 }
603 
604 static const struct got_error *
605 build_offset_index(struct got_packidx *p)
606 {
607 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
608 	unsigned int i, j, k;
609 
610 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
611 	    sizeof(p->sorted_offsets[0]));
612 	if (p->sorted_offsets == NULL)
613 		return got_error_from_errno("calloc");
614 
615 	if (p->nlargeobj > 0) {
616 		p->sorted_large_offsets = calloc(p->nlargeobj,
617 		    sizeof(p->sorted_large_offsets[0]));
618 		if (p->sorted_large_offsets == NULL)
619 			return got_error_from_errno("calloc");
620 	}
621 
622 	j = 0;
623 	k = 0;
624 	for (i = 0; i < nobj; i++) {
625 		uint32_t offset = be32toh(p->hdr.offsets[i]);
626 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
627 			uint64_t loffset;
628 			uint32_t idx;
629 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
630 			if (idx >= p->nlargeobj ||
631 			    p->nlargeobj == 0 ||
632 			    p->hdr.large_offsets == NULL)
633 				return got_error(GOT_ERR_BAD_PACKIDX);
634 			loffset = be64toh(p->hdr.large_offsets[idx]);
635 			p->sorted_large_offsets[j].offset = loffset;
636 			p->sorted_large_offsets[j].idx = i;
637 			j++;
638 		} else {
639 			p->sorted_offsets[k].offset = offset;
640 			p->sorted_offsets[k].idx = i;
641 			k++;
642 		}
643 	}
644 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
645 		return got_error(GOT_ERR_BAD_PACKIDX);
646 
647 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
648 	    sizeof(p->sorted_offsets[0]), offset_cmp);
649 
650 	if (p->sorted_large_offsets)
651 		qsort(p->sorted_large_offsets, p->nlargeobj,
652 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
653 
654 	return NULL;
655 }
656 
657 const struct got_error *
658 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
659 {
660 	const struct got_error *err;
661 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
662 	int i, left, right;
663 
664 	*idx = -1;
665 
666 	if (packidx->sorted_offsets == NULL) {
667 		err = build_offset_index(packidx);
668 		if (err)
669 			return err;
670 	}
671 
672 	if (offset >= 0x7fffffff) {
673 		uint64_t lo;
674 		left = 0, right = packidx->nlargeobj - 1;
675 		while (left <= right) {
676 			i = ((left + right) / 2);
677 			lo = packidx->sorted_large_offsets[i].offset;
678 			if (lo == offset) {
679 				*idx = packidx->sorted_large_offsets[i].idx;
680 				break;
681 			} else if (offset > lo)
682 				left = i + 1;
683 			else if (offset < lo)
684 				right = i - 1;
685 		}
686 	} else {
687 		uint32_t o;
688 		left = 0, right = totobj - packidx->nlargeobj - 1;
689 		while (left <= right) {
690 			i = ((left + right) / 2);
691 			o = packidx->sorted_offsets[i].offset;
692 			if (o == offset) {
693 				*idx = packidx->sorted_offsets[i].idx;
694 				break;
695 			} else if (offset > o)
696 				left = i + 1;
697 			else if (offset < o)
698 				right = i - 1;
699 		}
700 	}
701 
702 	return NULL;
703 }
704 
705 const struct got_error *
706 got_packidx_get_object_id(struct got_object_id *id,
707     struct got_packidx *packidx, int idx)
708 {
709 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
710 	struct got_packidx_object_id *oid;
711 
712 	if (idx < 0 || idx >= totobj)
713 		return got_error(GOT_ERR_NO_OBJ);
714 
715 	oid = &packidx->hdr.sorted_ids[idx];
716 	memcpy(id->hash, oid->hash, SHA256_DIGEST_LENGTH);
717 	id->algo = GOT_HASH_SHA256;
718 	return NULL;
719 }
720 
721 const struct got_error *
722 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
723     struct got_packidx *packidx, const char *id_str_prefix)
724 {
725 	const struct got_error *err = NULL;
726 	u_int8_t id0;
727 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
728 	char hex[3];
729 	size_t prefix_len = strlen(id_str_prefix);
730 	struct got_packidx_object_id *oid;
731 	uint32_t i = 0;
732 
733 	STAILQ_INIT(matched_ids);
734 
735 	if (prefix_len < 2)
736 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
737 
738 	hex[0] = id_str_prefix[0];
739 	hex[1] = id_str_prefix[1];
740 	hex[2] = '\0';
741 	if (!got_parse_xdigit(&id0, hex))
742 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
743 
744 	if (id0 > 0)
745 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
746 	oid = &packidx->hdr.sorted_ids[i];
747 	while (i < totobj && oid->hash[0] == id0) {
748 		char id_str[SHA256_DIGEST_STRING_LENGTH];
749 		struct got_object_qid *qid;
750 		int cmp;
751 
752 		if (!got_sha256_digest_to_str(oid->hash, id_str,
753 		    sizeof(id_str)))
754 		        return got_error(GOT_ERR_NO_SPACE);
755 
756 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
757 		if (cmp < 0) {
758 			oid = &packidx->hdr.sorted_ids[++i];
759 			continue;
760 		} else if (cmp > 0)
761 			break;
762 
763 		err = got_object_qid_alloc_partial(&qid);
764 		if (err)
765 			break;
766 		memcpy(qid->id.hash, oid->hash, SHA256_DIGEST_LENGTH);
767 		qid->id.algo = GOT_HASH_SHA256;
768 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
769 
770 		oid = &packidx->hdr.sorted_ids[++i];
771 	}
772 
773 	if (err)
774 		got_object_id_queue_free(matched_ids);
775 	return err;
776 }
777 
778 static void
779 set_max_datasize(void)
780 {
781 	struct rlimit rl;
782 
783 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
784 		return;
785 
786 	rl.rlim_cur = rl.rlim_max;
787 	setrlimit(RLIMIT_DATA, &rl);
788 }
789 
790 const struct got_error *
791 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
792 {
793 	const struct got_error *err = NULL;
794 	int imsg_fds[2];
795 	pid_t pid;
796 	struct imsgbuf *ibuf;
797 
798 	ibuf = calloc(1, sizeof(*ibuf));
799 	if (ibuf == NULL)
800 		return got_error_from_errno("calloc");
801 
802 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
803 	if (pack->privsep_child == NULL) {
804 		err = got_error_from_errno("calloc");
805 		free(ibuf);
806 		return err;
807 	}
808 	pack->child_has_tempfiles = 0;
809 	pack->child_has_delta_outfd = 0;
810 
811 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
812 		err = got_error_from_errno("socketpair");
813 		goto done;
814 	}
815 
816 	pid = fork();
817 	if (pid == -1) {
818 		err = got_error_from_errno("fork");
819 		goto done;
820 	} else if (pid == 0) {
821 		set_max_datasize();
822 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
823 		    pack->path_packfile);
824 		/* not reached */
825 	}
826 
827 	if (close(imsg_fds[1]) == -1)
828 		return got_error_from_errno("close");
829 	pack->privsep_child->imsg_fd = imsg_fds[0];
830 	pack->privsep_child->pid = pid;
831 	imsg_init(ibuf, imsg_fds[0]);
832 	pack->privsep_child->ibuf = ibuf;
833 
834 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
835 	if (err) {
836 		const struct got_error *child_err;
837 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
838 		child_err = got_privsep_wait_for_child(
839 		    pack->privsep_child->pid);
840 		if (child_err && err == NULL)
841 			err = child_err;
842 	}
843 done:
844 	if (err) {
845 		free(ibuf);
846 		free(pack->privsep_child);
847 		pack->privsep_child = NULL;
848 	}
849 	return err;
850 }
851 
852 static const struct got_error *
853 pack_stop_privsep_child(struct got_pack *pack)
854 {
855 	const struct got_error *err = NULL, *close_err = NULL;
856 
857 	if (pack->privsep_child == NULL)
858 		return NULL;
859 
860 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
861 	if (err)
862 		return err;
863 	if (close(pack->privsep_child->imsg_fd) == -1)
864 		close_err = got_error_from_errno("close");
865 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
866 	if (close_err && err == NULL)
867 		err = close_err;
868 	imsg_clear(pack->privsep_child->ibuf);
869 	free(pack->privsep_child->ibuf);
870 	free(pack->privsep_child);
871 	pack->privsep_child = NULL;
872 	return err;
873 }
874 
875 const struct got_error *
876 got_pack_close(struct got_pack *pack)
877 {
878 	const struct got_error *err = NULL;
879 
880 	err = pack_stop_privsep_child(pack);
881 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
882 		err = got_error_from_errno("munmap");
883 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
884 		err = got_error_from_errno("close");
885 	pack->fd = -1;
886 	free(pack->path_packfile);
887 	pack->path_packfile = NULL;
888 	pack->filesize = 0;
889 	if (pack->delta_cache) {
890 		got_delta_cache_free(pack->delta_cache);
891 		pack->delta_cache = NULL;
892 	}
893 
894 	/*
895 	 * Leave accumfd and basefd alone. They are managed by the
896 	 * repository layer and can be reused.
897 	 */
898 
899 	return err;
900 }
901 
902 const struct got_error *
903 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
904     struct got_pack *pack, off_t offset)
905 {
906 	uint8_t t = 0;
907 	uint64_t s = 0;
908 	uint8_t sizeN;
909 	size_t mapoff = 0;
910 	int i = 0;
911 
912 	*len = 0;
913 
914 	if (offset >= pack->filesize)
915 		return got_error(GOT_ERR_PACK_OFFSET);
916 
917 	if (pack->map) {
918 		if (offset > SIZE_MAX) {
919 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
920 			    "offset %lld overflows size_t",
921 			    (long long)offset);
922 		}
923 
924 		mapoff = (size_t)offset;
925 	} else {
926 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
927 			return got_error_from_errno("lseek");
928 	}
929 
930 	do {
931 		/* We do not support size values which don't fit in 64 bit. */
932 		if (i > 9)
933 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
934 			    "packfile offset %lld", (long long)offset);
935 
936 		if (pack->map) {
937 			if (mapoff + sizeof(sizeN) >= pack->filesize)
938 				return got_error(GOT_ERR_BAD_PACKFILE);
939 			sizeN = *(pack->map + mapoff);
940 			mapoff += sizeof(sizeN);
941 		} else {
942 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
943 			if (n < 0)
944 				return got_error_from_errno("read");
945 			if (n != sizeof(sizeN))
946 				return got_error(GOT_ERR_BAD_PACKFILE);
947 		}
948 		*len += sizeof(sizeN);
949 
950 		if (i == 0) {
951 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
952 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
953 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
954 		} else {
955 			size_t shift = 4 + 7 * (i - 1);
956 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
957 		}
958 		i++;
959 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
960 
961 	*type = t;
962 	*size = s;
963 	return NULL;
964 }
965 
966 static const struct got_error *
967 open_plain_object(struct got_object **obj, struct got_object_id *id,
968     uint8_t type, off_t offset, size_t size, int idx)
969 {
970 	*obj = calloc(1, sizeof(**obj));
971 	if (*obj == NULL)
972 		return got_error_from_errno("calloc");
973 
974 	(*obj)->type = type;
975 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
976 	(*obj)->pack_idx = idx;
977 	(*obj)->hdrlen = 0;
978 	(*obj)->size = size;
979 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
980 	(*obj)->pack_offset = offset;
981 
982 	return NULL;
983 }
984 
985 static const struct got_error *
986 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
987     off_t delta_offset)
988 {
989 	int64_t o = 0;
990 	uint8_t offN;
991 	int i = 0;
992 
993 	*offset = 0;
994 	*len = 0;
995 
996 	do {
997 		/* We do not support offset values which don't fit in 64 bit. */
998 		if (i > 8)
999 			return got_error(GOT_ERR_NO_SPACE);
1000 
1001 		if (pack->map) {
1002 			size_t mapoff;
1003 
1004 			if (delta_offset + *len > SIZE_MAX) {
1005 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
1006 				    "mapoff %lld would overflow size_t",
1007 				    (long long)delta_offset + *len);
1008 			}
1009 
1010 			mapoff = (size_t)delta_offset + *len;
1011 			if (mapoff + sizeof(offN) >= pack->filesize)
1012 				return got_error(GOT_ERR_PACK_OFFSET);
1013 			offN = *(pack->map + mapoff);
1014 		} else {
1015 			ssize_t n;
1016 			n = read(pack->fd, &offN, sizeof(offN));
1017 			if (n < 0)
1018 				return got_error_from_errno("read");
1019 			if (n != sizeof(offN))
1020 				return got_error(GOT_ERR_BAD_PACKFILE);
1021 		}
1022 		*len += sizeof(offN);
1023 
1024 		if (i == 0)
1025 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
1026 		else {
1027 			o++;
1028 			o <<= 7;
1029 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
1030 		}
1031 		i++;
1032 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
1033 
1034 	*offset = o;
1035 	return NULL;
1036 }
1037 
1038 const struct got_error *
1039 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
1040     struct got_pack *pack, off_t offset, size_t tslen)
1041 {
1042 	const struct got_error *err;
1043 	int64_t negoffset;
1044 	size_t negofflen;
1045 
1046 	*len = 0;
1047 
1048 	err = parse_negative_offset(&negoffset, &negofflen, pack,
1049 	    offset + tslen);
1050 	if (err)
1051 		return err;
1052 
1053 	/* Compute the base object's offset (must be in the same pack file). */
1054 	*base_offset = (offset - negoffset);
1055 	if (*base_offset <= 0)
1056 		return got_error(GOT_ERR_BAD_PACKFILE);
1057 
1058 	*len = negofflen;
1059 	return NULL;
1060 }
1061 
1062 static const struct got_error *
1063 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1064     size_t *delta_compressed_len, size_t delta_data_offset,
1065     struct got_pack *pack)
1066 {
1067 	const struct got_error *err = NULL;
1068 	size_t consumed = 0;
1069 
1070 	if (pack->map) {
1071 		if (delta_data_offset >= pack->filesize)
1072 			return got_error(GOT_ERR_PACK_OFFSET);
1073 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1074 		    &consumed, NULL, pack->map, delta_data_offset,
1075 		    pack->filesize - delta_data_offset);
1076 		if (err)
1077 			return err;
1078 	} else {
1079 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1080 			return got_error_from_errno("lseek");
1081 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1082 		    &consumed, NULL, 0, pack->fd);
1083 		if (err)
1084 			return err;
1085 	}
1086 
1087 	if (delta_compressed_len)
1088 		*delta_compressed_len = consumed;
1089 
1090 	return NULL;
1091 }
1092 
1093 static const struct got_error *
1094 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1095     int delta_type, size_t delta_size, off_t delta_data_offset)
1096 {
1097 	struct got_delta *delta;
1098 
1099 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1100 	    delta_data_offset);
1101 	if (delta == NULL)
1102 		return got_error_from_errno("got_delta_open");
1103 	/* delta is freed in got_object_close() */
1104 	deltas->nentries++;
1105 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1106 	return NULL;
1107 }
1108 
1109 static const struct got_error *
1110 resolve_offset_delta(struct got_delta_chain *deltas,
1111     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1112     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1113 {
1114 	const struct got_error *err;
1115 	off_t base_offset;
1116 	uint8_t base_type;
1117 	uint64_t base_size;
1118 	size_t base_tslen;
1119 	off_t delta_data_offset;
1120 	size_t consumed;
1121 
1122 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1123 	    delta_offset, tslen);
1124 	if (err)
1125 		return err;
1126 
1127 	delta_data_offset = delta_offset + tslen + consumed;
1128 	if (delta_data_offset >= pack->filesize)
1129 		return got_error(GOT_ERR_PACK_OFFSET);
1130 
1131 	if (pack->map == NULL) {
1132 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1133 		if (delta_data_offset == -1)
1134 			return got_error_from_errno("lseek");
1135 	}
1136 
1137 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1138 	    delta_data_offset);
1139 	if (err)
1140 		return err;
1141 
1142 	/* An offset delta must be in the same packfile. */
1143 	if (base_offset >= pack->filesize)
1144 		return got_error(GOT_ERR_PACK_OFFSET);
1145 
1146 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1147 	    &base_tslen, pack, base_offset);
1148 	if (err)
1149 		return err;
1150 
1151 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1152 	    base_tslen, base_type, base_size, recursion - 1);
1153 }
1154 
1155 const struct got_error *
1156 got_pack_parse_ref_delta(struct got_object_id *id,
1157     struct got_pack *pack, off_t delta_offset, int tslen)
1158 {
1159 	if (pack->map) {
1160 		size_t mapoff;
1161 
1162 		if (delta_offset + tslen > SIZE_MAX) {
1163 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1164 			    "mapoff %lld would overflow size_t",
1165 			    (long long)delta_offset + tslen);
1166 		}
1167 
1168 		mapoff = delta_offset + tslen;
1169 		if (mapoff + sizeof(*id) >= pack->filesize)
1170 			return got_error(GOT_ERR_PACK_OFFSET);
1171 		memcpy(id, pack->map + mapoff, sizeof(*id));
1172 	} else {
1173 		ssize_t n;
1174 		n = read(pack->fd, id, sizeof(*id));
1175 		if (n < 0)
1176 			return got_error_from_errno("read");
1177 		if (n != sizeof(*id))
1178 			return got_error(GOT_ERR_BAD_PACKFILE);
1179 	}
1180 
1181 	return NULL;
1182 }
1183 
1184 static const struct got_error *
1185 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1186     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1187     size_t delta_size, unsigned int recursion)
1188 {
1189 	const struct got_error *err;
1190 	struct got_object_id id;
1191 	int idx;
1192 	off_t base_offset;
1193 	uint8_t base_type;
1194 	uint64_t base_size;
1195 	size_t base_tslen;
1196 	off_t delta_data_offset;
1197 
1198 	if (delta_offset + tslen >= pack->filesize)
1199 		return got_error(GOT_ERR_PACK_OFFSET);
1200 
1201 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1202 	if (err)
1203 		return err;
1204 	if (pack->map) {
1205 		delta_data_offset = delta_offset + tslen + sizeof(id);
1206 	} else {
1207 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1208 		if (delta_data_offset == -1)
1209 			return got_error_from_errno("lseek");
1210 	}
1211 
1212 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1213 	    delta_data_offset);
1214 	if (err)
1215 		return err;
1216 
1217 	/* Delta base must be in the same pack file. */
1218 	idx = got_packidx_get_object_idx(packidx, &id);
1219 	if (idx == -1)
1220 		return got_error(GOT_ERR_NO_OBJ);
1221 
1222 	base_offset = got_packidx_get_object_offset(packidx, idx);
1223 	if (base_offset == -1)
1224 		return got_error(GOT_ERR_BAD_PACKIDX);
1225 
1226 	if (base_offset >= pack->filesize)
1227 		return got_error(GOT_ERR_PACK_OFFSET);
1228 
1229 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1230 	    &base_tslen, pack, base_offset);
1231 	if (err)
1232 		return err;
1233 
1234 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1235 	    base_tslen, base_type, base_size, recursion - 1);
1236 }
1237 
1238 const struct got_error *
1239 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1240     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1241     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1242 {
1243 	const struct got_error *err = NULL;
1244 
1245 	if (--recursion == 0)
1246 		return got_error(GOT_ERR_RECURSION);
1247 
1248 	switch (delta_type) {
1249 	case GOT_OBJ_TYPE_COMMIT:
1250 	case GOT_OBJ_TYPE_TREE:
1251 	case GOT_OBJ_TYPE_BLOB:
1252 	case GOT_OBJ_TYPE_TAG:
1253 		/* Plain types are the final delta base. Recursion ends. */
1254 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1255 		    delta_size, 0);
1256 		break;
1257 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1258 		err = resolve_offset_delta(deltas, packidx, pack,
1259 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1260 		break;
1261 	case GOT_OBJ_TYPE_REF_DELTA:
1262 		err = resolve_ref_delta(deltas, packidx, pack,
1263 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1264 		break;
1265 	default:
1266 		return got_error(GOT_ERR_OBJ_TYPE);
1267 	}
1268 
1269 	return err;
1270 }
1271 
1272 static const struct got_error *
1273 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1274     struct got_pack *pack, struct got_object_id *id, off_t offset,
1275     size_t tslen, int delta_type, size_t delta_size, int idx)
1276 {
1277 	const struct got_error *err = NULL;
1278 	int resolved_type;
1279 
1280 	*obj = calloc(1, sizeof(**obj));
1281 	if (*obj == NULL)
1282 		return got_error_from_errno("calloc");
1283 
1284 	(*obj)->flags = 0;
1285 	(*obj)->hdrlen = 0;
1286 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1287 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1288 	(*obj)->pack_offset = offset + tslen;
1289 
1290 	STAILQ_INIT(&(*obj)->deltas.entries);
1291 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1292 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1293 	(*obj)->pack_idx = idx;
1294 
1295 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1296 	    offset, tslen, delta_type, delta_size,
1297 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1298 	if (err)
1299 		goto done;
1300 
1301 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1302 	if (err)
1303 		goto done;
1304 	(*obj)->type = resolved_type;
1305 done:
1306 	if (err) {
1307 		got_object_close(*obj);
1308 		*obj = NULL;
1309 	}
1310 	return err;
1311 }
1312 
1313 const struct got_error *
1314 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1315     struct got_packidx *packidx, int idx, struct got_object_id *id)
1316 {
1317 	const struct got_error *err = NULL;
1318 	off_t offset;
1319 	uint8_t type;
1320 	uint64_t size;
1321 	size_t tslen;
1322 
1323 	*obj = NULL;
1324 
1325 	offset = got_packidx_get_object_offset(packidx, idx);
1326 	if (offset == -1)
1327 		return got_error(GOT_ERR_BAD_PACKIDX);
1328 
1329 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1330 	    pack, offset);
1331 	if (err)
1332 		return err;
1333 
1334 	switch (type) {
1335 	case GOT_OBJ_TYPE_COMMIT:
1336 	case GOT_OBJ_TYPE_TREE:
1337 	case GOT_OBJ_TYPE_BLOB:
1338 	case GOT_OBJ_TYPE_TAG:
1339 		err = open_plain_object(obj, id, type, offset + tslen,
1340 		    size, idx);
1341 		break;
1342 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1343 	case GOT_OBJ_TYPE_REF_DELTA:
1344 		err = open_delta_object(obj, packidx, pack, id, offset,
1345 		    tslen, type, size, idx);
1346 		break;
1347 	default:
1348 		err = got_error(GOT_ERR_OBJ_TYPE);
1349 		break;
1350 	}
1351 
1352 	return err;
1353 }
1354 
1355 const struct got_error *
1356 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1357     struct got_delta_chain *deltas, struct got_pack *pack)
1358 {
1359 	struct got_delta *delta;
1360 	uint64_t base_size = 0, result_size = 0;
1361 
1362 	*max_size = 0;
1363 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1364 		/* Plain object types are the delta base. */
1365 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1366 		    delta->type != GOT_OBJ_TYPE_TREE &&
1367 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1368 		    delta->type != GOT_OBJ_TYPE_TAG) {
1369 			const struct got_error *err;
1370 			uint8_t *delta_buf = NULL;
1371 			size_t delta_len;
1372 			int cached = 1;
1373 
1374 			if (pack->delta_cache) {
1375 				got_delta_cache_get(&delta_buf, &delta_len,
1376 				    pack->delta_cache, delta->data_offset);
1377 			}
1378 			if (delta_buf == NULL) {
1379 				cached = 0;
1380 				err = read_delta_data(&delta_buf, &delta_len,
1381 				    NULL, delta->data_offset, pack);
1382 				if (err)
1383 					return err;
1384 			}
1385 			if (pack->delta_cache && !cached) {
1386 				err = got_delta_cache_add(pack->delta_cache,
1387 				    delta->data_offset, delta_buf, delta_len);
1388 				if (err == NULL)
1389 					cached = 1;
1390 				else if (err->code != GOT_ERR_NO_SPACE) {
1391 					free(delta_buf);
1392 					return err;
1393 				}
1394 			}
1395 			err = got_delta_get_sizes(&base_size, &result_size,
1396 			    delta_buf, delta_len);
1397 			if (!cached)
1398 				free(delta_buf);
1399 			if (err)
1400 				return err;
1401 		} else
1402 			base_size = delta->size;
1403 		if (base_size > *max_size)
1404 			*max_size = base_size;
1405 		if (result_size > *max_size)
1406 			*max_size = result_size;
1407 	}
1408 
1409 	return NULL;
1410 }
1411 
1412 const struct got_error *
1413 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1414     struct got_pack *pack)
1415 {
1416 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1417 		return got_error(GOT_ERR_OBJ_TYPE);
1418 
1419 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1420 }
1421 
1422 const struct got_error *
1423 got_pack_dump_delta_chain_to_file(size_t *result_size,
1424     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1425     FILE *base_file, FILE *accum_file)
1426 {
1427 	const struct got_error *err = NULL;
1428 	struct got_delta *delta;
1429 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1430 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1431 	/* We process small enough files entirely in memory for speed. */
1432 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1433 	uint64_t max_size = 0;
1434 	int n = 0;
1435 
1436 	*result_size = 0;
1437 
1438 	if (STAILQ_EMPTY(&deltas->entries))
1439 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1440 
1441 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1442 		return got_error_from_errno("fseeko");
1443 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1444 		return got_error_from_errno("fseeko");
1445 
1446 	/* Deltas are ordered in ascending order. */
1447 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1448 		uint8_t *delta_buf = NULL;
1449 		uint64_t base_size, result_size = 0;
1450 		int cached = 1;
1451 		if (n == 0) {
1452 			size_t mapoff;
1453 			off_t delta_data_offset;
1454 
1455 			/* Plain object types are the delta base. */
1456 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1457 			    delta->type != GOT_OBJ_TYPE_TREE &&
1458 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1459 			    delta->type != GOT_OBJ_TYPE_TAG) {
1460 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1461 				goto done;
1462 			}
1463 
1464 			delta_data_offset = delta->offset + delta->tslen;
1465 			if (delta_data_offset >= pack->filesize) {
1466 				err = got_error(GOT_ERR_PACK_OFFSET);
1467 				goto done;
1468 			}
1469 			if (pack->map == NULL) {
1470 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1471 				    == -1) {
1472 					err = got_error_from_errno("lseek");
1473 					goto done;
1474 				}
1475 			}
1476 			if (delta->size > max_size)
1477 				max_size = delta->size;
1478 			if (max_size > max_bufsize) {
1479 				if (pack->map) {
1480 					if (delta_data_offset > SIZE_MAX) {
1481 						return got_error_fmt(
1482 						    GOT_ERR_RANGE,
1483 						    "delta offset %lld "
1484 						    "overflows size_t",
1485 						    (long long)
1486 						    delta_data_offset);
1487 					}
1488 
1489 					mapoff = delta_data_offset;
1490 					err = got_inflate_to_file_mmap(
1491 					    &base_bufsz, NULL, NULL, pack->map,
1492 					    mapoff, pack->filesize - mapoff,
1493 					    base_file);
1494 				} else
1495 					err = got_inflate_to_file_fd(
1496 					    &base_bufsz, NULL, NULL, pack->fd,
1497 					    base_file);
1498 			} else {
1499 				accum_buf = malloc(max_size);
1500 				if (accum_buf == NULL) {
1501 					err = got_error_from_errno("malloc");
1502 					goto done;
1503 				}
1504 				accum_bufsz = max_size;
1505 				if (pack->map) {
1506 					if (delta_data_offset > SIZE_MAX) {
1507 						return got_error_fmt(
1508 						    GOT_ERR_RANGE,
1509 						    "delta offset %lld "
1510 						    "overflows size_t",
1511 						    (long long)
1512 						    delta_data_offset);
1513 					}
1514 
1515 					mapoff = delta_data_offset;
1516 					err = got_inflate_to_mem_mmap(&base_buf,
1517 					    &base_bufsz, NULL, NULL,
1518 					    pack->map, mapoff,
1519 					    pack->filesize - mapoff);
1520 				} else
1521 					err = got_inflate_to_mem_fd(&base_buf,
1522 					    &base_bufsz, NULL, NULL, max_size,
1523 					    pack->fd);
1524 			}
1525 			if (err)
1526 				goto done;
1527 			n++;
1528 			if (base_buf == NULL)
1529 				rewind(base_file);
1530 			continue;
1531 		}
1532 
1533 		if (pack->delta_cache) {
1534 			got_delta_cache_get(&delta_buf, &delta_len,
1535 			    pack->delta_cache, delta->data_offset);
1536 		}
1537 		if (delta_buf == NULL) {
1538 			cached = 0;
1539 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1540 			    delta->data_offset, pack);
1541 			if (err)
1542 				goto done;
1543 		}
1544 		if (pack->delta_cache && !cached) {
1545 			err = got_delta_cache_add(pack->delta_cache,
1546 			    delta->data_offset, delta_buf, delta_len);
1547 			if (err == NULL)
1548 				cached = 1;
1549 			else if (err->code != GOT_ERR_NO_SPACE) {
1550 				free(delta_buf);
1551 				goto done;
1552 			}
1553 		}
1554 
1555 		err = got_delta_get_sizes(&base_size, &result_size,
1556 		    delta_buf, delta_len);
1557 		if (err) {
1558 			if (!cached)
1559 				free(delta_buf);
1560 			goto done;
1561 		}
1562 		if (base_size > max_size)
1563 			max_size = base_size;
1564 		if (result_size > max_size)
1565 			max_size = result_size;
1566 
1567 		if (base_buf && max_size > max_bufsize) {
1568 			/* Switch from buffers to temporary files. */
1569 			size_t w = fwrite(base_buf, 1, base_bufsz,
1570 			    base_file);
1571 			if (w != base_bufsz) {
1572 				err = got_ferror(outfile, GOT_ERR_IO);
1573 				if (!cached)
1574 					free(delta_buf);
1575 				goto done;
1576 			}
1577 			free(base_buf);
1578 			base_buf = NULL;
1579 			free(accum_buf);
1580 			accum_buf = NULL;
1581 		}
1582 
1583 		if (base_buf && max_size > base_bufsz) {
1584 			uint8_t *p = realloc(base_buf, max_size);
1585 			if (p == NULL) {
1586 				err = got_error_from_errno("realloc");
1587 				if (!cached)
1588 					free(delta_buf);
1589 				goto done;
1590 			}
1591 			base_buf = p;
1592 			base_bufsz = max_size;
1593 		}
1594 
1595 		if (accum_buf && max_size > accum_bufsz) {
1596 			uint8_t *p = realloc(accum_buf, max_size);
1597 			if (p == NULL) {
1598 				err = got_error_from_errno("realloc");
1599 				if (!cached)
1600 					free(delta_buf);
1601 				goto done;
1602 			}
1603 			accum_buf = p;
1604 			accum_bufsz = max_size;
1605 		}
1606 
1607 		if (base_buf) {
1608 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1609 			    delta_buf, delta_len, accum_buf,
1610 			    &accum_size, max_size);
1611 			n++;
1612 		} else {
1613 			err = got_delta_apply(base_file, delta_buf,
1614 			    delta_len,
1615 			    /* Final delta application writes to output file. */
1616 			    ++n < deltas->nentries ? accum_file : outfile,
1617 			    &accum_size);
1618 		}
1619 		if (!cached)
1620 			free(delta_buf);
1621 		if (err)
1622 			goto done;
1623 
1624 		if (n < deltas->nentries) {
1625 			/* Accumulated delta becomes the new base. */
1626 			if (base_buf) {
1627 				uint8_t *tmp = accum_buf;
1628 				size_t tmp_size = accum_bufsz;
1629 				accum_buf = base_buf;
1630 				accum_bufsz = base_bufsz;
1631 				base_buf = tmp;
1632 				base_bufsz = tmp_size;
1633 			} else {
1634 				FILE *tmp = accum_file;
1635 				accum_file = base_file;
1636 				base_file = tmp;
1637 				rewind(base_file);
1638 				rewind(accum_file);
1639 			}
1640 		}
1641 	}
1642 
1643 done:
1644 	free(base_buf);
1645 	if (accum_buf) {
1646 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1647 		free(accum_buf);
1648 		if (len != accum_size)
1649 			err = got_ferror(outfile, GOT_ERR_IO);
1650 	}
1651 	rewind(outfile);
1652 	if (err == NULL)
1653 		*result_size = accum_size;
1654 	return err;
1655 }
1656 
1657 const struct got_error *
1658 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1659     struct got_delta_chain *deltas, struct got_pack *pack)
1660 {
1661 	const struct got_error *err = NULL;
1662 	struct got_delta *delta;
1663 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1664 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1665 	uint64_t max_size = 0;
1666 	int n = 0;
1667 
1668 	*outbuf = NULL;
1669 	*outlen = 0;
1670 
1671 	if (STAILQ_EMPTY(&deltas->entries))
1672 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1673 
1674 	/* Deltas are ordered in ascending order. */
1675 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1676 		uint8_t *delta_buf = NULL;
1677 		uint64_t base_size, result_size = 0;
1678 		int cached = 1;
1679 		if (n == 0) {
1680 			off_t delta_data_offset;
1681 
1682 			/* Plain object types are the delta base. */
1683 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1684 			    delta->type != GOT_OBJ_TYPE_TREE &&
1685 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1686 			    delta->type != GOT_OBJ_TYPE_TAG) {
1687 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1688 				goto done;
1689 			}
1690 
1691 			delta_data_offset = delta->offset + delta->tslen;
1692 			if (delta_data_offset >= pack->filesize) {
1693 				err = got_error(GOT_ERR_PACK_OFFSET);
1694 				goto done;
1695 			}
1696 
1697 			if (delta->size > max_size)
1698 				max_size = delta->size;
1699 
1700 			if (pack->map) {
1701 				size_t mapoff;
1702 
1703 				if (delta_data_offset > SIZE_MAX) {
1704 					return got_error_fmt(GOT_ERR_RANGE,
1705 					    "delta %lld offset would "
1706 					    "overflow size_t",
1707 					    (long long)delta_data_offset);
1708 				}
1709 
1710 				mapoff = delta_data_offset;
1711 				err = got_inflate_to_mem_mmap(&base_buf,
1712 				    &base_bufsz, NULL, NULL, pack->map,
1713 				    mapoff, pack->filesize - mapoff);
1714 			} else {
1715 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1716 				    == -1) {
1717 					err = got_error_from_errno("lseek");
1718 					goto done;
1719 				}
1720 				err = got_inflate_to_mem_fd(&base_buf,
1721 				    &base_bufsz, NULL, NULL, max_size,
1722 				    pack->fd);
1723 			}
1724 			if (err)
1725 				goto done;
1726 			n++;
1727 			continue;
1728 		}
1729 
1730 		if (pack->delta_cache) {
1731 			got_delta_cache_get(&delta_buf, &delta_len,
1732 			    pack->delta_cache, delta->data_offset);
1733 		}
1734 		if (delta_buf == NULL) {
1735 			cached = 0;
1736 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1737 			    delta->data_offset, pack);
1738 			if (err)
1739 				goto done;
1740 		}
1741 		if (pack->delta_cache && !cached) {
1742 			err = got_delta_cache_add(pack->delta_cache,
1743 			    delta->data_offset, delta_buf, delta_len);
1744 			if (err == NULL)
1745 				cached = 1;
1746 			else if (err->code != GOT_ERR_NO_SPACE) {
1747 				free(delta_buf);
1748 				goto done;
1749 			}
1750 		}
1751 
1752 		err = got_delta_get_sizes(&base_size, &result_size,
1753 		    delta_buf, delta_len);
1754 		if (err) {
1755 			if (!cached)
1756 				free(delta_buf);
1757 			goto done;
1758 		}
1759 		if (base_size > max_size)
1760 			max_size = base_size;
1761 		if (result_size > max_size)
1762 			max_size = result_size;
1763 
1764 		if (max_size > base_bufsz) {
1765 			uint8_t *p = realloc(base_buf, max_size);
1766 			if (p == NULL) {
1767 				err = got_error_from_errno("realloc");
1768 				if (!cached)
1769 					free(delta_buf);
1770 				goto done;
1771 			}
1772 			base_buf = p;
1773 			base_bufsz = max_size;
1774 		}
1775 
1776 		if (max_size > accum_bufsz) {
1777 			uint8_t *p = realloc(accum_buf, max_size);
1778 			if (p == NULL) {
1779 				err = got_error_from_errno("realloc");
1780 				if (!cached)
1781 					free(delta_buf);
1782 				goto done;
1783 			}
1784 			accum_buf = p;
1785 			accum_bufsz = max_size;
1786 		}
1787 
1788 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1789 		    delta_buf, delta_len, accum_buf,
1790 		    &accum_size, max_size);
1791 		if (!cached)
1792 			free(delta_buf);
1793 		n++;
1794 		if (err)
1795 			goto done;
1796 
1797 		if (n < deltas->nentries) {
1798 			/* Accumulated delta becomes the new base. */
1799 			uint8_t *tmp = accum_buf;
1800 			size_t tmp_size = accum_bufsz;
1801 			accum_buf = base_buf;
1802 			accum_bufsz = base_bufsz;
1803 			base_buf = tmp;
1804 			base_bufsz = tmp_size;
1805 		}
1806 	}
1807 
1808 done:
1809 	free(base_buf);
1810 	if (err) {
1811 		free(accum_buf);
1812 		*outbuf = NULL;
1813 		*outlen = 0;
1814 	} else {
1815 		*outbuf = accum_buf;
1816 		*outlen = accum_size;
1817 	}
1818 	return err;
1819 }
1820 
1821 const struct got_error *
1822 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1823     FILE *outfile, FILE *base_file, FILE *accum_file)
1824 {
1825 	const struct got_error *err = NULL;
1826 
1827 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1828 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1829 
1830 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1831 		if (obj->pack_offset >= pack->filesize)
1832 			return got_error(GOT_ERR_PACK_OFFSET);
1833 
1834 		if (pack->map) {
1835 			size_t mapoff;
1836 
1837 			if (obj->pack_offset > SIZE_MAX) {
1838 				return got_error_fmt(GOT_ERR_RANGE,
1839 				    "pack offset %lld would overflow size_t",
1840 				    (long long)obj->pack_offset);
1841 			}
1842 
1843 			mapoff = obj->pack_offset;
1844 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1845 			    pack->map, mapoff, pack->filesize - mapoff,
1846 			    outfile);
1847 		} else {
1848 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1849 				return got_error_from_errno("lseek");
1850 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1851 			    pack->fd, outfile);
1852 		}
1853 	} else
1854 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1855 		    &obj->deltas, pack, outfile, base_file, accum_file);
1856 
1857 	return err;
1858 }
1859 
1860 const struct got_error *
1861 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1862     struct got_object *obj, struct got_pack *pack)
1863 {
1864 	const struct got_error *err = NULL;
1865 
1866 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1867 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1868 
1869 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1870 		if (obj->pack_offset >= pack->filesize)
1871 			return got_error(GOT_ERR_PACK_OFFSET);
1872 		if (pack->map) {
1873 			size_t mapoff;
1874 
1875 			if (obj->pack_offset > SIZE_MAX) {
1876 				return got_error_fmt(GOT_ERR_RANGE,
1877 				    "pack offset %lld would overflow size_t",
1878 				    (long long)obj->pack_offset);
1879 			}
1880 
1881 			mapoff = obj->pack_offset;
1882 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1883 			    pack->map, mapoff, pack->filesize - mapoff);
1884 		} else {
1885 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1886 				return got_error_from_errno("lseek");
1887 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1888 			    obj->size, pack->fd);
1889 		}
1890 	} else
1891 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1892 		    pack);
1893 
1894 	return err;
1895 }
1896 
1897 static const struct got_error *
1898 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1899     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1900     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1901 {
1902 	const struct got_error *err = NULL;
1903 
1904 	/* Validate decompression and obtain the decompressed size. */
1905 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1906 	    delta_data_offset, pack);
1907 	if (err)
1908 		return err;
1909 
1910 	/* Read delta base/result sizes from head of delta stream. */
1911 	err = got_delta_get_sizes(base_size, result_size,
1912 	    *delta_buf, *delta_len);
1913 	if (err)
1914 		goto done;
1915 
1916 	/* Discard decompressed delta and read it again in compressed form. */
1917 	free(*delta_buf);
1918 	*delta_buf = malloc(*delta_len_compressed);
1919 	if (*delta_buf == NULL) {
1920 		err = got_error_from_errno("malloc");
1921 		goto done;
1922 	}
1923 	if (pack->map) {
1924 		if (delta_data_offset >= pack->filesize) {
1925 			err = got_error(GOT_ERR_PACK_OFFSET);
1926 			goto done;
1927 		}
1928 		memcpy(*delta_buf, pack->map + delta_data_offset,
1929 		    *delta_len_compressed);
1930 	} else {
1931 		ssize_t n;
1932 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1933 			err = got_error_from_errno("lseek");
1934 			goto done;
1935 		}
1936 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1937 		if (n < 0) {
1938 			err = got_error_from_errno("read");
1939 			goto done;
1940 		} else if (n != *delta_len_compressed) {
1941 			err = got_error(GOT_ERR_IO);
1942 			goto done;
1943 		}
1944 	}
1945 done:
1946 	if (err) {
1947 		free(*delta_buf);
1948 		*delta_buf = NULL;
1949 		*delta_len = 0;
1950 		*delta_len_compressed = 0;
1951 		*base_size = 0;
1952 		*result_size = 0;
1953 	}
1954 	return err;
1955 }
1956 
1957 const struct got_error *
1958 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1959     size_t *delta_compressed_size, off_t *delta_offset,
1960     off_t *delta_data_offset, off_t *base_offset,
1961     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1962     struct got_pack *pack, struct got_packidx *packidx, int idx)
1963 {
1964 	const struct got_error *err = NULL;
1965 	off_t offset;
1966 	uint8_t type;
1967 	uint64_t size;
1968 	size_t tslen, delta_hdrlen;
1969 
1970 	*delta_buf = NULL;
1971 	*delta_size = 0;
1972 	*delta_compressed_size = 0;
1973 	*delta_offset = 0;
1974 	*delta_data_offset = 0;
1975 	*base_offset = 0;
1976 	*base_size = 0;
1977 	*result_size = 0;
1978 
1979 	offset = got_packidx_get_object_offset(packidx, idx);
1980 	if (offset == -1)
1981 		return got_error(GOT_ERR_BAD_PACKIDX);
1982 
1983 	if (offset >= pack->filesize)
1984 		return got_error(GOT_ERR_PACK_OFFSET);
1985 
1986 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1987 	    pack, offset);
1988 	if (err)
1989 		return err;
1990 
1991 	if (tslen + size < tslen || offset + size < size ||
1992 	    tslen + offset < tslen)
1993 		return got_error(GOT_ERR_PACK_OFFSET);
1994 
1995 	switch (type) {
1996 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1997 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1998 		    pack, offset, tslen);
1999 		if (err)
2000 			return err;
2001 		break;
2002 	case GOT_OBJ_TYPE_REF_DELTA:
2003 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
2004 		if (err)
2005 			return err;
2006 		delta_hdrlen = SHA256_DIGEST_LENGTH;
2007 		break;
2008 	default:
2009 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
2010 		    "non-delta object type %d found at offset %lld",
2011 		    type, (long long)offset);
2012 	}
2013 
2014 	if (tslen + delta_hdrlen < delta_hdrlen ||
2015 	    offset + delta_hdrlen < delta_hdrlen)
2016 		return got_error(GOT_ERR_BAD_DELTA);
2017 
2018 	*delta_data_offset = offset + tslen + delta_hdrlen;
2019 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
2020 	    base_size, result_size, *delta_data_offset, pack, packidx);
2021 	if (err)
2022 		return err;
2023 
2024 	if (*delta_size != size) {
2025 		err = got_error(GOT_ERR_BAD_DELTA);
2026 		goto done;
2027 	}
2028 
2029 	*delta_offset = offset;
2030 done:
2031 	if (err) {
2032 		free(*delta_buf);
2033 		*delta_buf = NULL;
2034 		*delta_size = 0;
2035 		*delta_compressed_size = 0;
2036 		*delta_offset = 0;
2037 		*base_offset = 0;
2038 		*base_size = 0;
2039 		*result_size = 0;
2040 	}
2041 	return err;
2042 }