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_qid.h"
49 #include "got_lib_object_parse.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_pack.h"
52 
53 #ifndef nitems
54 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
55 #endif
56 
57 #ifndef MIN
58 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
59 #endif
60 
61 static const struct got_error *
62 verify_fanout_table(uint32_t *fanout_table)
63 {
64 	int i;
65 
66 	for (i = 0; i < 0xff - 1; i++) {
67 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
68 			return got_error(GOT_ERR_BAD_PACKIDX);
69 	}
70 
71 	return NULL;
72 }
73 
74 const struct got_error *
75 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
76 {
77 	const struct got_error *err = NULL;
78 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
79 	struct got_packidx_v2_hdr *h;
80 	struct got_hash ctx;
81 	uint8_t hash[GOT_HASH_DIGEST_MAXLEN];
82 	size_t nobj, len_fanout, len_ids, offset, remain;
83 	ssize_t n;
84 	int i;
85 
86 	got_hash_init(&ctx, algo);
87 
88 	h = &p->hdr;
89 	offset = 0;
90 	remain = p->len;
91 
92 	if (remain < sizeof(*h->magic)) {
93 		err = got_error(GOT_ERR_BAD_PACKIDX);
94 		goto done;
95 	}
96 	if (p->map)
97 		h->magic = (uint32_t *)(p->map + offset);
98 	else {
99 		h->magic = malloc(sizeof(*h->magic));
100 		if (h->magic == NULL) {
101 			err = got_error_from_errno("malloc");
102 			goto done;
103 		}
104 		n = read(p->fd, h->magic, sizeof(*h->magic));
105 		if (n < 0) {
106 			err = got_error_from_errno("read");
107 			goto done;
108 		} else if (n != sizeof(*h->magic)) {
109 			err = got_error(GOT_ERR_BAD_PACKIDX);
110 			goto done;
111 		}
112 	}
113 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
114 		err = got_error(GOT_ERR_BAD_PACKIDX);
115 		goto done;
116 	}
117 	offset += sizeof(*h->magic);
118 	remain -= sizeof(*h->magic);
119 
120 	if (verify)
121 		got_hash_update(&ctx, h->magic, sizeof(*h->magic));
122 
123 	if (remain < sizeof(*h->version)) {
124 		err = got_error(GOT_ERR_BAD_PACKIDX);
125 		goto done;
126 	}
127 	if (p->map)
128 		h->version = (uint32_t *)(p->map + offset);
129 	else {
130 		h->version = malloc(sizeof(*h->version));
131 		if (h->version == NULL) {
132 			err = got_error_from_errno("malloc");
133 			goto done;
134 		}
135 		n = read(p->fd, h->version, sizeof(*h->version));
136 		if (n < 0) {
137 			err = got_error_from_errno("read");
138 			goto done;
139 		} else if (n != sizeof(*h->version)) {
140 			err = got_error(GOT_ERR_BAD_PACKIDX);
141 			goto done;
142 		}
143 	}
144 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
145 		err = got_error(GOT_ERR_BAD_PACKIDX);
146 		goto done;
147 	}
148 	offset += sizeof(*h->version);
149 	remain -= sizeof(*h->version);
150 
151 	if (verify)
152 		got_hash_update(&ctx, h->version, sizeof(*h->version));
153 
154 	len_fanout =
155 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
156 	if (remain < len_fanout) {
157 		err = got_error(GOT_ERR_BAD_PACKIDX);
158 		goto done;
159 	}
160 	if (p->map)
161 		h->fanout_table = (uint32_t *)(p->map + offset);
162 	else {
163 		h->fanout_table = malloc(len_fanout);
164 		if (h->fanout_table == NULL) {
165 			err = got_error_from_errno("malloc");
166 			goto done;
167 		}
168 		n = read(p->fd, h->fanout_table, len_fanout);
169 		if (n < 0) {
170 			err = got_error_from_errno("read");
171 			goto done;
172 		} else if (n != len_fanout) {
173 			err = got_error(GOT_ERR_BAD_PACKIDX);
174 			goto done;
175 		}
176 	}
177 	err = verify_fanout_table(h->fanout_table);
178 	if (err)
179 		goto done;
180 	if (verify)
181 		got_hash_update(&ctx, h->fanout_table, len_fanout);
182 	offset += len_fanout;
183 	remain -= len_fanout;
184 
185 	nobj = be32toh(h->fanout_table[0xff]);
186 	len_ids = nobj * sizeof(*h->sorted_ids);
187 	if (len_ids <= nobj || len_ids > remain) {
188 		err = got_error(GOT_ERR_BAD_PACKIDX);
189 		goto done;
190 	}
191 	if (p->map)
192 		h->sorted_ids =
193 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
194 	else {
195 		h->sorted_ids = malloc(len_ids);
196 		if (h->sorted_ids == NULL) {
197 			err = got_error(GOT_ERR_BAD_PACKIDX);
198 			goto done;
199 		}
200 		n = read(p->fd, h->sorted_ids, len_ids);
201 		if (n < 0)
202 			err = got_error_from_errno("read");
203 		else if (n != len_ids) {
204 			err = got_error(GOT_ERR_BAD_PACKIDX);
205 			goto done;
206 		}
207 	}
208 	if (verify)
209 		got_hash_update(&ctx, h->sorted_ids, len_ids);
210 	offset += len_ids;
211 	remain -= len_ids;
212 
213 	if (remain < nobj * sizeof(*h->crc32)) {
214 		err = got_error(GOT_ERR_BAD_PACKIDX);
215 		goto done;
216 	}
217 	if (p->map)
218 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
219 	else {
220 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
221 		if (h->crc32 == NULL) {
222 			err = got_error_from_errno("malloc");
223 			goto done;
224 		}
225 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
226 		if (n < 0)
227 			err = got_error_from_errno("read");
228 		else if (n != nobj * sizeof(*h->crc32)) {
229 			err = got_error(GOT_ERR_BAD_PACKIDX);
230 			goto done;
231 		}
232 	}
233 	if (verify)
234 		got_hash_update(&ctx, h->crc32, nobj * sizeof(*h->crc32));
235 	remain -= nobj * sizeof(*h->crc32);
236 	offset += nobj * sizeof(*h->crc32);
237 
238 	if (remain < nobj * sizeof(*h->offsets)) {
239 		err = got_error(GOT_ERR_BAD_PACKIDX);
240 		goto done;
241 	}
242 	if (p->map)
243 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
244 	else {
245 		h->offsets = malloc(nobj * sizeof(*h->offsets));
246 		if (h->offsets == NULL) {
247 			err = got_error_from_errno("malloc");
248 			goto done;
249 		}
250 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
251 		if (n < 0)
252 			err = got_error_from_errno("read");
253 		else if (n != nobj * sizeof(*h->offsets)) {
254 			err = got_error(GOT_ERR_BAD_PACKIDX);
255 			goto done;
256 		}
257 	}
258 	if (verify)
259 		got_hash_update(&ctx, h->offsets, nobj * sizeof(*h->offsets));
260 	remain -= nobj * sizeof(*h->offsets);
261 	offset += nobj * sizeof(*h->offsets);
262 
263 	/* Large file offsets are contained only in files > 2GB. */
264 	if (verify || packfile_size > 0x7fffffff) {
265 		for (i = 0; i < nobj; i++) {
266 			uint32_t o = h->offsets[i];
267 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
268 				p->nlargeobj++;
269 		}
270 	}
271 	if (p->nlargeobj == 0)
272 		goto checksum;
273 	else if (packfile_size <= 0x7fffffff) {
274 		err = got_error(GOT_ERR_BAD_PACKIDX);
275 		goto done;
276 	}
277 
278 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
279 		err = got_error(GOT_ERR_BAD_PACKIDX);
280 		goto done;
281 	}
282 	if (p->map)
283 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
284 	else {
285 		h->large_offsets = malloc(p->nlargeobj *
286 		    sizeof(*h->large_offsets));
287 		if (h->large_offsets == NULL) {
288 			err = got_error_from_errno("malloc");
289 			goto done;
290 		}
291 		n = read(p->fd, h->large_offsets,
292 		    p->nlargeobj * sizeof(*h->large_offsets));
293 		if (n < 0)
294 			err = got_error_from_errno("read");
295 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
296 			err = got_error(GOT_ERR_BAD_PACKIDX);
297 			goto done;
298 		}
299 	}
300 	if (verify)
301 		got_hash_update(&ctx, h->large_offsets,
302 		    p->nlargeobj * sizeof(*h->large_offsets));
303 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
304 	offset += p->nlargeobj * sizeof(*h->large_offsets);
305 
306 checksum:
307 	if (remain < sizeof(*h->trailer)) {
308 		err = got_error(GOT_ERR_BAD_PACKIDX);
309 		goto done;
310 	}
311 	if (p->map)
312 		h->trailer =
313 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
314 	else {
315 		h->trailer = malloc(sizeof(*h->trailer));
316 		if (h->trailer == NULL) {
317 			err = got_error_from_errno("malloc");
318 			goto done;
319 		}
320 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
321 		if (n < 0)
322 			err = got_error_from_errno("read");
323 		else if (n != sizeof(*h->trailer)) {
324 			err = got_error(GOT_ERR_BAD_PACKIDX);
325 			goto done;
326 		}
327 	}
328 	if (verify) {
329 		got_hash_update(&ctx, h->trailer->packfile_sha1,
330 		    SHA1_DIGEST_LENGTH);
331 		got_hash_final(&ctx, hash);
332 		if (got_hash_cmp(ctx.algo, hash, h->trailer->packidx_sha1) != 0)
333 			err = got_error(GOT_ERR_PACKIDX_CSUM);
334 	}
335 done:
336 	return err;
337 }
338 
339 const struct got_error *
340 got_packidx_open(struct got_packidx **packidx,
341     int dir_fd, const char *relpath, int verify)
342 {
343 	const struct got_error *err = NULL;
344 	struct got_packidx *p = NULL;
345 	char *pack_relpath;
346 	struct stat idx_sb, pack_sb;
347 
348 	*packidx = NULL;
349 
350 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
351 	if (err)
352 		return err;
353 
354 	/*
355 	 * Ensure that a corresponding pack file exists.
356 	 * Some Git repositories have this problem. Git seems to ignore
357 	 * the existence of lonely pack index files but we do not.
358 	 */
359 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
360 		if (errno == ENOENT) {
361 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
362 			    "%s", relpath);
363 		} else
364 			err = got_error_from_errno2("fstatat", pack_relpath);
365 		goto done;
366 	}
367 
368 	p = calloc(1, sizeof(*p));
369 	if (p == NULL) {
370 		err = got_error_from_errno("calloc");
371 		goto done;
372 	}
373 
374 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
375 	if (p->fd == -1) {
376 		err = got_error_from_errno2("openat", relpath);
377 		goto done;
378 	}
379 
380 	if (fstat(p->fd, &idx_sb) != 0) {
381 		err = got_error_from_errno2("fstat", relpath);
382 		goto done;
383 	}
384 	p->len = idx_sb.st_size;
385 	if (p->len < sizeof(p->hdr)) {
386 		err = got_error(GOT_ERR_BAD_PACKIDX);
387 		goto done;
388 	}
389 
390 	p->path_packidx = strdup(relpath);
391 	if (p->path_packidx == NULL) {
392 		err = got_error_from_errno("strdup");
393 		goto done;
394 	}
395 
396 #ifndef GOT_PACK_NO_MMAP
397 	if (p->len > 0 && p->len <= SIZE_MAX) {
398 		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
399 		if (p->map == MAP_FAILED) {
400 			if (errno != ENOMEM) {
401 				err = got_error_from_errno("mmap");
402 				goto done;
403 			}
404 			p->map = NULL; /* fall back to read(2) */
405 		}
406 	}
407 #endif
408 
409 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
410 done:
411 	if (err) {
412 		if (p)
413 			got_packidx_close(p);
414 	} else
415 		*packidx = p;
416 	free(pack_relpath);
417 	return err;
418 }
419 
420 const struct got_error *
421 got_packidx_close(struct got_packidx *packidx)
422 {
423 	const struct got_error *err = NULL;
424 
425 	free(packidx->path_packidx);
426 	if (packidx->map) {
427 		if (munmap(packidx->map, packidx->len) == -1)
428 			err = got_error_from_errno("munmap");
429 	} else {
430 		free(packidx->hdr.magic);
431 		free(packidx->hdr.version);
432 		free(packidx->hdr.fanout_table);
433 		free(packidx->hdr.sorted_ids);
434 		free(packidx->hdr.crc32);
435 		free(packidx->hdr.offsets);
436 		free(packidx->hdr.large_offsets);
437 		free(packidx->hdr.trailer);
438 	}
439 	if (close(packidx->fd) == -1 && err == NULL)
440 		err = got_error_from_errno("close");
441 	free(packidx->sorted_offsets);
442 	free(packidx->sorted_large_offsets);
443 	free(packidx);
444 
445 	return err;
446 }
447 
448 const struct got_error *
449 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
450 {
451 	size_t size;
452 
453 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
454 	size = strlen(path_packidx) + 2;
455 	if (size < GOT_PACKFILE_NAMELEN + 1)
456 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
457 
458 	*path_packfile = malloc(size);
459 	if (*path_packfile == NULL)
460 		return got_error_from_errno("malloc");
461 
462 	/* Copy up to and excluding ".idx". */
463 	if (strlcpy(*path_packfile, path_packidx,
464 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
465 		return got_error(GOT_ERR_NO_SPACE);
466 
467 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
468 		return got_error(GOT_ERR_NO_SPACE);
469 
470 	return NULL;
471 }
472 
473 off_t
474 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
475 {
476 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
477 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
478 		uint64_t loffset;
479 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
480 		if (idx < 0 || idx >= packidx->nlargeobj ||
481 		    packidx->hdr.large_offsets == NULL)
482 			return -1;
483 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
484 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
485 	}
486 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
487 }
488 
489 int
490 got_packidx_get_object_idx(struct got_packidx *packidx,
491     struct got_object_id *id)
492 {
493 	u_int8_t id0 = id->sha1[0];
494 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
495 	int left = 0, right = totobj - 1;
496 
497 	if (id0 > 0)
498 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
499 
500 	while (left <= right) {
501 		struct got_packidx_object_id *oid;
502 		int i, cmp;
503 
504 		i = ((left + right) / 2);
505 		oid = &packidx->hdr.sorted_ids[i];
506 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
507 		if (cmp == 0)
508 			return i;
509 		else if (cmp > 0)
510 			left = i + 1;
511 		else if (cmp < 0)
512 			right = i - 1;
513 	}
514 
515 	return -1;
516 }
517 
518 static int
519 offset_cmp(const void *pa, const void *pb)
520 {
521 	const struct got_pack_offset_index *a, *b;
522 
523 	a = (const struct got_pack_offset_index *)pa;
524 	b = (const struct got_pack_offset_index *)pb;
525 
526 	if (a->offset < b->offset)
527 		return -1;
528 	else if (a->offset > b->offset)
529 		return 1;
530 
531 	return 0;
532 }
533 
534 static int
535 large_offset_cmp(const void *pa, const void *pb)
536 {
537 	const struct got_pack_large_offset_index *a, *b;
538 
539 	a = (const struct got_pack_large_offset_index *)pa;
540 	b = (const struct got_pack_large_offset_index *)pb;
541 
542 	if (a->offset < b->offset)
543 		return -1;
544 	else if (a->offset > b->offset)
545 		return 1;
546 
547 	return 0;
548 }
549 
550 static const struct got_error *
551 build_offset_index(struct got_packidx *p)
552 {
553 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
554 	unsigned int i, j, k;
555 
556 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
557 	    sizeof(p->sorted_offsets[0]));
558 	if (p->sorted_offsets == NULL)
559 		return got_error_from_errno("calloc");
560 
561 	if (p->nlargeobj > 0) {
562 		p->sorted_large_offsets = calloc(p->nlargeobj,
563 		    sizeof(p->sorted_large_offsets[0]));
564 		if (p->sorted_large_offsets == NULL)
565 			return got_error_from_errno("calloc");
566 	}
567 
568 	j = 0;
569 	k = 0;
570 	for (i = 0; i < nobj; i++) {
571 		uint32_t offset = be32toh(p->hdr.offsets[i]);
572 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
573 			uint64_t loffset;
574 			uint32_t idx;
575 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
576 			if (idx >= p->nlargeobj ||
577 			    p->nlargeobj == 0 ||
578 			    p->hdr.large_offsets == NULL)
579 				return got_error(GOT_ERR_BAD_PACKIDX);
580 			loffset = be64toh(p->hdr.large_offsets[idx]);
581 			p->sorted_large_offsets[j].offset = loffset;
582 			p->sorted_large_offsets[j].idx = i;
583 			j++;
584 		} else {
585 			p->sorted_offsets[k].offset = offset;
586 			p->sorted_offsets[k].idx = i;
587 			k++;
588 		}
589 	}
590 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
591 		return got_error(GOT_ERR_BAD_PACKIDX);
592 
593 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
594 	    sizeof(p->sorted_offsets[0]), offset_cmp);
595 
596 	if (p->sorted_large_offsets)
597 		qsort(p->sorted_large_offsets, p->nlargeobj,
598 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
599 
600 	return NULL;
601 }
602 
603 const struct got_error *
604 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
605 {
606 	const struct got_error *err;
607 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
608 	int i, left, right;
609 
610 	*idx = -1;
611 
612 	if (packidx->sorted_offsets == NULL) {
613 		err = build_offset_index(packidx);
614 		if (err)
615 			return err;
616 	}
617 
618 	if (offset >= 0x7fffffff) {
619 		uint64_t lo;
620 		left = 0, right = packidx->nlargeobj - 1;
621 		while (left <= right) {
622 			i = ((left + right) / 2);
623 			lo = packidx->sorted_large_offsets[i].offset;
624 			if (lo == offset) {
625 				*idx = packidx->sorted_large_offsets[i].idx;
626 				break;
627 			} else if (offset > lo)
628 				left = i + 1;
629 			else if (offset < lo)
630 				right = i - 1;
631 		}
632 	} else {
633 		uint32_t o;
634 		left = 0, right = totobj - packidx->nlargeobj - 1;
635 		while (left <= right) {
636 			i = ((left + right) / 2);
637 			o = packidx->sorted_offsets[i].offset;
638 			if (o == offset) {
639 				*idx = packidx->sorted_offsets[i].idx;
640 				break;
641 			} else if (offset > o)
642 				left = i + 1;
643 			else if (offset < o)
644 				right = i - 1;
645 		}
646 	}
647 
648 	return NULL;
649 }
650 
651 const struct got_error *
652 got_packidx_get_object_id(struct got_object_id *id,
653     struct got_packidx *packidx, int idx)
654 {
655 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
656 	struct got_packidx_object_id *oid;
657 
658 	if (idx < 0 || idx >= totobj)
659 		return got_error(GOT_ERR_NO_OBJ);
660 
661 	oid = &packidx->hdr.sorted_ids[idx];
662 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
663 	return NULL;
664 }
665 
666 const struct got_error *
667 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
668     struct got_packidx *packidx, const char *id_str_prefix)
669 {
670 	const struct got_error *err = NULL;
671 	u_int8_t id0;
672 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
673 	char hex[3];
674 	size_t prefix_len = strlen(id_str_prefix);
675 	struct got_packidx_object_id *oid;
676 	uint32_t i = 0;
677 
678 	STAILQ_INIT(matched_ids);
679 
680 	if (prefix_len < 2)
681 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
682 
683 	hex[0] = id_str_prefix[0];
684 	hex[1] = id_str_prefix[1];
685 	hex[2] = '\0';
686 	if (!got_parse_xdigit(&id0, hex))
687 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
688 
689 	if (id0 > 0)
690 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
691 	oid = &packidx->hdr.sorted_ids[i];
692 	while (i < totobj && oid->sha1[0] == id0) {
693 		char id_str[SHA1_DIGEST_STRING_LENGTH];
694 		struct got_object_qid *qid;
695 		int cmp;
696 
697 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
698 		        return got_error(GOT_ERR_NO_SPACE);
699 
700 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
701 		if (cmp < 0) {
702 			oid = &packidx->hdr.sorted_ids[++i];
703 			continue;
704 		} else if (cmp > 0)
705 			break;
706 
707 		err = got_object_qid_alloc_partial(&qid);
708 		if (err)
709 			break;
710 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
711 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
712 
713 		oid = &packidx->hdr.sorted_ids[++i];
714 	}
715 
716 	if (err)
717 		got_object_id_queue_free(matched_ids);
718 	return err;
719 }
720 
721 static void
722 set_max_datasize(void)
723 {
724 	struct rlimit rl;
725 
726 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
727 		return;
728 
729 	rl.rlim_cur = rl.rlim_max;
730 	setrlimit(RLIMIT_DATA, &rl);
731 }
732 
733 const struct got_error *
734 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
735 {
736 	const struct got_error *err = NULL;
737 	int imsg_fds[2];
738 	pid_t pid;
739 	struct imsgbuf *ibuf;
740 
741 	ibuf = calloc(1, sizeof(*ibuf));
742 	if (ibuf == NULL)
743 		return got_error_from_errno("calloc");
744 
745 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
746 	if (pack->privsep_child == NULL) {
747 		err = got_error_from_errno("calloc");
748 		free(ibuf);
749 		return err;
750 	}
751 	pack->child_has_tempfiles = 0;
752 	pack->child_has_delta_outfd = 0;
753 
754 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
755 		err = got_error_from_errno("socketpair");
756 		goto done;
757 	}
758 
759 	pid = fork();
760 	if (pid == -1) {
761 		err = got_error_from_errno("fork");
762 		goto done;
763 	} else if (pid == 0) {
764 		set_max_datasize();
765 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
766 		    pack->path_packfile);
767 		/* not reached */
768 	}
769 
770 	if (close(imsg_fds[1]) == -1)
771 		return got_error_from_errno("close");
772 	pack->privsep_child->imsg_fd = imsg_fds[0];
773 	pack->privsep_child->pid = pid;
774 	imsg_init(ibuf, imsg_fds[0]);
775 	pack->privsep_child->ibuf = ibuf;
776 
777 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
778 	if (err) {
779 		const struct got_error *child_err;
780 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
781 		child_err = got_privsep_wait_for_child(
782 		    pack->privsep_child->pid);
783 		if (child_err && err == NULL)
784 			err = child_err;
785 	}
786 done:
787 	if (err) {
788 		free(ibuf);
789 		free(pack->privsep_child);
790 		pack->privsep_child = NULL;
791 	}
792 	return err;
793 }
794 
795 static const struct got_error *
796 pack_stop_privsep_child(struct got_pack *pack)
797 {
798 	const struct got_error *err = NULL, *close_err = NULL;
799 
800 	if (pack->privsep_child == NULL)
801 		return NULL;
802 
803 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
804 	if (err)
805 		return err;
806 	if (close(pack->privsep_child->imsg_fd) == -1)
807 		close_err = got_error_from_errno("close");
808 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
809 	if (close_err && err == NULL)
810 		err = close_err;
811 	imsg_clear(pack->privsep_child->ibuf);
812 	free(pack->privsep_child->ibuf);
813 	free(pack->privsep_child);
814 	pack->privsep_child = NULL;
815 	return err;
816 }
817 
818 const struct got_error *
819 got_pack_close(struct got_pack *pack)
820 {
821 	const struct got_error *err = NULL;
822 
823 	err = pack_stop_privsep_child(pack);
824 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
825 		err = got_error_from_errno("munmap");
826 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
827 		err = got_error_from_errno("close");
828 	pack->fd = -1;
829 	free(pack->path_packfile);
830 	pack->path_packfile = NULL;
831 	pack->filesize = 0;
832 	if (pack->delta_cache) {
833 		got_delta_cache_free(pack->delta_cache);
834 		pack->delta_cache = NULL;
835 	}
836 
837 	/*
838 	 * Leave accumfd and basefd alone. They are managed by the
839 	 * repository layer and can be reused.
840 	 */
841 
842 	return err;
843 }
844 
845 const struct got_error *
846 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
847     struct got_pack *pack, off_t offset)
848 {
849 	uint8_t t = 0;
850 	uint64_t s = 0;
851 	uint8_t sizeN;
852 	size_t mapoff = 0;
853 	int i = 0;
854 
855 	*len = 0;
856 
857 	if (offset >= pack->filesize)
858 		return got_error(GOT_ERR_PACK_OFFSET);
859 
860 	if (pack->map) {
861 		if (offset > SIZE_MAX) {
862 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
863 			    "offset %lld overflows size_t",
864 			    (long long)offset);
865 		}
866 
867 		mapoff = (size_t)offset;
868 	} else {
869 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
870 			return got_error_from_errno("lseek");
871 	}
872 
873 	do {
874 		/* We do not support size values which don't fit in 64 bit. */
875 		if (i > 9)
876 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
877 			    "packfile offset %lld", (long long)offset);
878 
879 		if (pack->map) {
880 			if (mapoff + sizeof(sizeN) >= pack->filesize)
881 				return got_error(GOT_ERR_BAD_PACKFILE);
882 			sizeN = *(pack->map + mapoff);
883 			mapoff += sizeof(sizeN);
884 		} else {
885 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
886 			if (n < 0)
887 				return got_error_from_errno("read");
888 			if (n != sizeof(sizeN))
889 				return got_error(GOT_ERR_BAD_PACKFILE);
890 		}
891 		*len += sizeof(sizeN);
892 
893 		if (i == 0) {
894 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
895 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
896 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
897 		} else {
898 			size_t shift = 4 + 7 * (i - 1);
899 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
900 		}
901 		i++;
902 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
903 
904 	*type = t;
905 	*size = s;
906 	return NULL;
907 }
908 
909 static const struct got_error *
910 open_plain_object(struct got_object **obj, struct got_object_id *id,
911     uint8_t type, off_t offset, size_t size, int idx)
912 {
913 	*obj = calloc(1, sizeof(**obj));
914 	if (*obj == NULL)
915 		return got_error_from_errno("calloc");
916 
917 	(*obj)->type = type;
918 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
919 	(*obj)->pack_idx = idx;
920 	(*obj)->hdrlen = 0;
921 	(*obj)->size = size;
922 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
923 	(*obj)->pack_offset = offset;
924 
925 	return NULL;
926 }
927 
928 static const struct got_error *
929 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
930     off_t delta_offset)
931 {
932 	int64_t o = 0;
933 	uint8_t offN;
934 	int i = 0;
935 
936 	*offset = 0;
937 	*len = 0;
938 
939 	do {
940 		/* We do not support offset values which don't fit in 64 bit. */
941 		if (i > 8)
942 			return got_error(GOT_ERR_NO_SPACE);
943 
944 		if (pack->map) {
945 			size_t mapoff;
946 
947 			if (delta_offset + *len > SIZE_MAX) {
948 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
949 				    "mapoff %lld would overflow size_t",
950 				    (long long)delta_offset + *len);
951 			}
952 
953 			mapoff = (size_t)delta_offset + *len;
954 			if (mapoff + sizeof(offN) >= pack->filesize)
955 				return got_error(GOT_ERR_PACK_OFFSET);
956 			offN = *(pack->map + mapoff);
957 		} else {
958 			ssize_t n;
959 			n = read(pack->fd, &offN, sizeof(offN));
960 			if (n < 0)
961 				return got_error_from_errno("read");
962 			if (n != sizeof(offN))
963 				return got_error(GOT_ERR_BAD_PACKFILE);
964 		}
965 		*len += sizeof(offN);
966 
967 		if (i == 0)
968 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
969 		else {
970 			o++;
971 			o <<= 7;
972 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
973 		}
974 		i++;
975 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
976 
977 	*offset = o;
978 	return NULL;
979 }
980 
981 const struct got_error *
982 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
983     struct got_pack *pack, off_t offset, size_t tslen)
984 {
985 	const struct got_error *err;
986 	int64_t negoffset;
987 	size_t negofflen;
988 
989 	*len = 0;
990 
991 	err = parse_negative_offset(&negoffset, &negofflen, pack,
992 	    offset + tslen);
993 	if (err)
994 		return err;
995 
996 	/* Compute the base object's offset (must be in the same pack file). */
997 	*base_offset = (offset - negoffset);
998 	if (*base_offset <= 0)
999 		return got_error(GOT_ERR_BAD_PACKFILE);
1000 
1001 	*len = negofflen;
1002 	return NULL;
1003 }
1004 
1005 static const struct got_error *
1006 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1007     size_t *delta_compressed_len, size_t delta_data_offset,
1008     struct got_pack *pack)
1009 {
1010 	const struct got_error *err = NULL;
1011 	size_t consumed = 0;
1012 
1013 	if (pack->map) {
1014 		if (delta_data_offset >= pack->filesize)
1015 			return got_error(GOT_ERR_PACK_OFFSET);
1016 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1017 		    &consumed, NULL, pack->map, delta_data_offset,
1018 		    pack->filesize - delta_data_offset);
1019 		if (err)
1020 			return err;
1021 	} else {
1022 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1023 			return got_error_from_errno("lseek");
1024 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1025 		    &consumed, NULL, 0, pack->fd);
1026 		if (err)
1027 			return err;
1028 	}
1029 
1030 	if (delta_compressed_len)
1031 		*delta_compressed_len = consumed;
1032 
1033 	return NULL;
1034 }
1035 
1036 static const struct got_error *
1037 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1038     int delta_type, size_t delta_size, off_t delta_data_offset)
1039 {
1040 	struct got_delta *delta;
1041 
1042 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1043 	    delta_data_offset);
1044 	if (delta == NULL)
1045 		return got_error_from_errno("got_delta_open");
1046 	/* delta is freed in got_object_close() */
1047 	deltas->nentries++;
1048 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1049 	return NULL;
1050 }
1051 
1052 static const struct got_error *
1053 resolve_offset_delta(struct got_delta_chain *deltas,
1054     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1055     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1056 {
1057 	const struct got_error *err;
1058 	off_t base_offset;
1059 	uint8_t base_type;
1060 	uint64_t base_size;
1061 	size_t base_tslen;
1062 	off_t delta_data_offset;
1063 	size_t consumed;
1064 
1065 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1066 	    delta_offset, tslen);
1067 	if (err)
1068 		return err;
1069 
1070 	delta_data_offset = delta_offset + tslen + consumed;
1071 	if (delta_data_offset >= pack->filesize)
1072 		return got_error(GOT_ERR_PACK_OFFSET);
1073 
1074 	if (pack->map == NULL) {
1075 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1076 		if (delta_data_offset == -1)
1077 			return got_error_from_errno("lseek");
1078 	}
1079 
1080 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1081 	    delta_data_offset);
1082 	if (err)
1083 		return err;
1084 
1085 	/* An offset delta must be in the same packfile. */
1086 	if (base_offset >= pack->filesize)
1087 		return got_error(GOT_ERR_PACK_OFFSET);
1088 
1089 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1090 	    &base_tslen, pack, base_offset);
1091 	if (err)
1092 		return err;
1093 
1094 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1095 	    base_tslen, base_type, base_size, recursion - 1);
1096 }
1097 
1098 const struct got_error *
1099 got_pack_parse_ref_delta(struct got_object_id *id,
1100     struct got_pack *pack, off_t delta_offset, int tslen)
1101 {
1102 	if (pack->map) {
1103 		size_t mapoff;
1104 
1105 		if (delta_offset + tslen > SIZE_MAX) {
1106 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1107 			    "mapoff %lld would overflow size_t",
1108 			    (long long)delta_offset + tslen);
1109 		}
1110 
1111 		mapoff = delta_offset + tslen;
1112 		if (mapoff + sizeof(*id) >= pack->filesize)
1113 			return got_error(GOT_ERR_PACK_OFFSET);
1114 		memcpy(id, pack->map + mapoff, sizeof(*id));
1115 	} else {
1116 		ssize_t n;
1117 		n = read(pack->fd, id, sizeof(*id));
1118 		if (n < 0)
1119 			return got_error_from_errno("read");
1120 		if (n != sizeof(*id))
1121 			return got_error(GOT_ERR_BAD_PACKFILE);
1122 	}
1123 
1124 	return NULL;
1125 }
1126 
1127 static const struct got_error *
1128 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1129     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1130     size_t delta_size, unsigned int recursion)
1131 {
1132 	const struct got_error *err;
1133 	struct got_object_id id;
1134 	int idx;
1135 	off_t base_offset;
1136 	uint8_t base_type;
1137 	uint64_t base_size;
1138 	size_t base_tslen;
1139 	off_t delta_data_offset;
1140 
1141 	if (delta_offset + tslen >= pack->filesize)
1142 		return got_error(GOT_ERR_PACK_OFFSET);
1143 
1144 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1145 	if (err)
1146 		return err;
1147 	if (pack->map) {
1148 		delta_data_offset = delta_offset + tslen + SHA1_DIGEST_LENGTH;
1149 	} else {
1150 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1151 		if (delta_data_offset == -1)
1152 			return got_error_from_errno("lseek");
1153 	}
1154 
1155 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1156 	    delta_data_offset);
1157 	if (err)
1158 		return err;
1159 
1160 	/* Delta base must be in the same pack file. */
1161 	idx = got_packidx_get_object_idx(packidx, &id);
1162 	if (idx == -1)
1163 		return got_error(GOT_ERR_NO_OBJ);
1164 
1165 	base_offset = got_packidx_get_object_offset(packidx, idx);
1166 	if (base_offset == -1)
1167 		return got_error(GOT_ERR_BAD_PACKIDX);
1168 
1169 	if (base_offset >= pack->filesize)
1170 		return got_error(GOT_ERR_PACK_OFFSET);
1171 
1172 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1173 	    &base_tslen, pack, base_offset);
1174 	if (err)
1175 		return err;
1176 
1177 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1178 	    base_tslen, base_type, base_size, recursion - 1);
1179 }
1180 
1181 const struct got_error *
1182 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1183     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1184     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1185 {
1186 	const struct got_error *err = NULL;
1187 
1188 	if (--recursion == 0)
1189 		return got_error(GOT_ERR_RECURSION);
1190 
1191 	switch (delta_type) {
1192 	case GOT_OBJ_TYPE_COMMIT:
1193 	case GOT_OBJ_TYPE_TREE:
1194 	case GOT_OBJ_TYPE_BLOB:
1195 	case GOT_OBJ_TYPE_TAG:
1196 		/* Plain types are the final delta base. Recursion ends. */
1197 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1198 		    delta_size, 0);
1199 		break;
1200 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1201 		err = resolve_offset_delta(deltas, packidx, pack,
1202 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1203 		break;
1204 	case GOT_OBJ_TYPE_REF_DELTA:
1205 		err = resolve_ref_delta(deltas, packidx, pack,
1206 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1207 		break;
1208 	default:
1209 		return got_error(GOT_ERR_OBJ_TYPE);
1210 	}
1211 
1212 	return err;
1213 }
1214 
1215 static const struct got_error *
1216 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1217     struct got_pack *pack, struct got_object_id *id, off_t offset,
1218     size_t tslen, int delta_type, size_t delta_size, int idx)
1219 {
1220 	const struct got_error *err = NULL;
1221 	int resolved_type;
1222 
1223 	*obj = calloc(1, sizeof(**obj));
1224 	if (*obj == NULL)
1225 		return got_error_from_errno("calloc");
1226 
1227 	(*obj)->flags = 0;
1228 	(*obj)->hdrlen = 0;
1229 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1230 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1231 	(*obj)->pack_offset = offset + tslen;
1232 
1233 	STAILQ_INIT(&(*obj)->deltas.entries);
1234 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1235 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1236 	(*obj)->pack_idx = idx;
1237 
1238 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1239 	    offset, tslen, delta_type, delta_size,
1240 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1241 	if (err)
1242 		goto done;
1243 
1244 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1245 	if (err)
1246 		goto done;
1247 	(*obj)->type = resolved_type;
1248 done:
1249 	if (err) {
1250 		got_object_close(*obj);
1251 		*obj = NULL;
1252 	}
1253 	return err;
1254 }
1255 
1256 const struct got_error *
1257 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1258     struct got_packidx *packidx, int idx, struct got_object_id *id)
1259 {
1260 	const struct got_error *err = NULL;
1261 	off_t offset;
1262 	uint8_t type;
1263 	uint64_t size;
1264 	size_t tslen;
1265 
1266 	*obj = NULL;
1267 
1268 	offset = got_packidx_get_object_offset(packidx, idx);
1269 	if (offset == -1)
1270 		return got_error(GOT_ERR_BAD_PACKIDX);
1271 
1272 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1273 	    pack, offset);
1274 	if (err)
1275 		return err;
1276 
1277 	switch (type) {
1278 	case GOT_OBJ_TYPE_COMMIT:
1279 	case GOT_OBJ_TYPE_TREE:
1280 	case GOT_OBJ_TYPE_BLOB:
1281 	case GOT_OBJ_TYPE_TAG:
1282 		err = open_plain_object(obj, id, type, offset + tslen,
1283 		    size, idx);
1284 		break;
1285 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1286 	case GOT_OBJ_TYPE_REF_DELTA:
1287 		err = open_delta_object(obj, packidx, pack, id, offset,
1288 		    tslen, type, size, idx);
1289 		break;
1290 	default:
1291 		err = got_error(GOT_ERR_OBJ_TYPE);
1292 		break;
1293 	}
1294 
1295 	return err;
1296 }
1297 
1298 const struct got_error *
1299 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1300     struct got_delta_chain *deltas, struct got_pack *pack)
1301 {
1302 	struct got_delta *delta;
1303 	uint64_t base_size = 0, result_size = 0;
1304 
1305 	*max_size = 0;
1306 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1307 		/* Plain object types are the delta base. */
1308 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1309 		    delta->type != GOT_OBJ_TYPE_TREE &&
1310 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1311 		    delta->type != GOT_OBJ_TYPE_TAG) {
1312 			const struct got_error *err;
1313 			uint8_t *delta_buf = NULL;
1314 			size_t delta_len;
1315 			int cached = 1;
1316 
1317 			if (pack->delta_cache) {
1318 				got_delta_cache_get(&delta_buf, &delta_len,
1319 				    pack->delta_cache, delta->data_offset);
1320 			}
1321 			if (delta_buf == NULL) {
1322 				cached = 0;
1323 				err = read_delta_data(&delta_buf, &delta_len,
1324 				    NULL, delta->data_offset, pack);
1325 				if (err)
1326 					return err;
1327 			}
1328 			if (pack->delta_cache && !cached) {
1329 				err = got_delta_cache_add(pack->delta_cache,
1330 				    delta->data_offset, delta_buf, delta_len);
1331 				if (err == NULL)
1332 					cached = 1;
1333 				else if (err->code != GOT_ERR_NO_SPACE) {
1334 					free(delta_buf);
1335 					return err;
1336 				}
1337 			}
1338 			err = got_delta_get_sizes(&base_size, &result_size,
1339 			    delta_buf, delta_len);
1340 			if (!cached)
1341 				free(delta_buf);
1342 			if (err)
1343 				return err;
1344 		} else
1345 			base_size = delta->size;
1346 		if (base_size > *max_size)
1347 			*max_size = base_size;
1348 		if (result_size > *max_size)
1349 			*max_size = result_size;
1350 	}
1351 
1352 	return NULL;
1353 }
1354 
1355 const struct got_error *
1356 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1357     struct got_pack *pack)
1358 {
1359 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1360 		return got_error(GOT_ERR_OBJ_TYPE);
1361 
1362 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1363 }
1364 
1365 const struct got_error *
1366 got_pack_dump_delta_chain_to_file(size_t *result_size,
1367     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1368     FILE *base_file, FILE *accum_file)
1369 {
1370 	const struct got_error *err = NULL;
1371 	struct got_delta *delta;
1372 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1373 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1374 	/* We process small enough files entirely in memory for speed. */
1375 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1376 	uint64_t max_size = 0;
1377 	int n = 0;
1378 
1379 	*result_size = 0;
1380 
1381 	if (STAILQ_EMPTY(&deltas->entries))
1382 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1383 
1384 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1385 		return got_error_from_errno("fseeko");
1386 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1387 		return got_error_from_errno("fseeko");
1388 
1389 	/* Deltas are ordered in ascending order. */
1390 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1391 		uint8_t *delta_buf = NULL;
1392 		uint64_t base_size, result_size = 0;
1393 		int cached = 1;
1394 		if (n == 0) {
1395 			size_t mapoff;
1396 			off_t delta_data_offset;
1397 
1398 			/* Plain object types are the delta base. */
1399 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1400 			    delta->type != GOT_OBJ_TYPE_TREE &&
1401 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1402 			    delta->type != GOT_OBJ_TYPE_TAG) {
1403 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1404 				goto done;
1405 			}
1406 
1407 			delta_data_offset = delta->offset + delta->tslen;
1408 			if (delta_data_offset >= pack->filesize) {
1409 				err = got_error(GOT_ERR_PACK_OFFSET);
1410 				goto done;
1411 			}
1412 			if (pack->map == NULL) {
1413 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1414 				    == -1) {
1415 					err = got_error_from_errno("lseek");
1416 					goto done;
1417 				}
1418 			}
1419 			if (delta->size > max_size)
1420 				max_size = delta->size;
1421 			if (max_size > max_bufsize) {
1422 				if (pack->map) {
1423 					if (delta_data_offset > SIZE_MAX) {
1424 						return got_error_fmt(
1425 						    GOT_ERR_RANGE,
1426 						    "delta offset %lld "
1427 						    "overflows size_t",
1428 						    (long long)
1429 						    delta_data_offset);
1430 					}
1431 
1432 					mapoff = delta_data_offset;
1433 					err = got_inflate_to_file_mmap(
1434 					    &base_bufsz, NULL, NULL, pack->map,
1435 					    mapoff, pack->filesize - mapoff,
1436 					    base_file);
1437 				} else
1438 					err = got_inflate_to_file_fd(
1439 					    &base_bufsz, NULL, NULL, pack->fd,
1440 					    base_file);
1441 			} else {
1442 				accum_buf = malloc(max_size);
1443 				if (accum_buf == NULL) {
1444 					err = got_error_from_errno("malloc");
1445 					goto done;
1446 				}
1447 				accum_bufsz = max_size;
1448 				if (pack->map) {
1449 					if (delta_data_offset > SIZE_MAX) {
1450 						return got_error_fmt(
1451 						    GOT_ERR_RANGE,
1452 						    "delta offset %lld "
1453 						    "overflows size_t",
1454 						    (long long)
1455 						    delta_data_offset);
1456 					}
1457 
1458 					mapoff = delta_data_offset;
1459 					err = got_inflate_to_mem_mmap(&base_buf,
1460 					    &base_bufsz, NULL, NULL,
1461 					    pack->map, mapoff,
1462 					    pack->filesize - mapoff);
1463 				} else
1464 					err = got_inflate_to_mem_fd(&base_buf,
1465 					    &base_bufsz, NULL, NULL, max_size,
1466 					    pack->fd);
1467 			}
1468 			if (err)
1469 				goto done;
1470 			n++;
1471 			if (base_buf == NULL)
1472 				rewind(base_file);
1473 			continue;
1474 		}
1475 
1476 		if (pack->delta_cache) {
1477 			got_delta_cache_get(&delta_buf, &delta_len,
1478 			    pack->delta_cache, delta->data_offset);
1479 		}
1480 		if (delta_buf == NULL) {
1481 			cached = 0;
1482 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1483 			    delta->data_offset, pack);
1484 			if (err)
1485 				goto done;
1486 		}
1487 		if (pack->delta_cache && !cached) {
1488 			err = got_delta_cache_add(pack->delta_cache,
1489 			    delta->data_offset, delta_buf, delta_len);
1490 			if (err == NULL)
1491 				cached = 1;
1492 			else if (err->code != GOT_ERR_NO_SPACE) {
1493 				free(delta_buf);
1494 				goto done;
1495 			}
1496 		}
1497 
1498 		err = got_delta_get_sizes(&base_size, &result_size,
1499 		    delta_buf, delta_len);
1500 		if (err) {
1501 			if (!cached)
1502 				free(delta_buf);
1503 			goto done;
1504 		}
1505 		if (base_size > max_size)
1506 			max_size = base_size;
1507 		if (result_size > max_size)
1508 			max_size = result_size;
1509 
1510 		if (base_buf && max_size > max_bufsize) {
1511 			/* Switch from buffers to temporary files. */
1512 			size_t w = fwrite(base_buf, 1, base_bufsz,
1513 			    base_file);
1514 			if (w != base_bufsz) {
1515 				err = got_ferror(outfile, GOT_ERR_IO);
1516 				if (!cached)
1517 					free(delta_buf);
1518 				goto done;
1519 			}
1520 			free(base_buf);
1521 			base_buf = NULL;
1522 			free(accum_buf);
1523 			accum_buf = NULL;
1524 		}
1525 
1526 		if (base_buf && max_size > base_bufsz) {
1527 			uint8_t *p = realloc(base_buf, max_size);
1528 			if (p == NULL) {
1529 				err = got_error_from_errno("realloc");
1530 				if (!cached)
1531 					free(delta_buf);
1532 				goto done;
1533 			}
1534 			base_buf = p;
1535 			base_bufsz = max_size;
1536 		}
1537 
1538 		if (accum_buf && max_size > accum_bufsz) {
1539 			uint8_t *p = realloc(accum_buf, max_size);
1540 			if (p == NULL) {
1541 				err = got_error_from_errno("realloc");
1542 				if (!cached)
1543 					free(delta_buf);
1544 				goto done;
1545 			}
1546 			accum_buf = p;
1547 			accum_bufsz = max_size;
1548 		}
1549 
1550 		if (base_buf) {
1551 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1552 			    delta_buf, delta_len, accum_buf,
1553 			    &accum_size, max_size);
1554 			n++;
1555 		} else {
1556 			err = got_delta_apply(base_file, delta_buf,
1557 			    delta_len,
1558 			    /* Final delta application writes to output file. */
1559 			    ++n < deltas->nentries ? accum_file : outfile,
1560 			    &accum_size);
1561 		}
1562 		if (!cached)
1563 			free(delta_buf);
1564 		if (err)
1565 			goto done;
1566 
1567 		if (n < deltas->nentries) {
1568 			/* Accumulated delta becomes the new base. */
1569 			if (base_buf) {
1570 				uint8_t *tmp = accum_buf;
1571 				size_t tmp_size = accum_bufsz;
1572 				accum_buf = base_buf;
1573 				accum_bufsz = base_bufsz;
1574 				base_buf = tmp;
1575 				base_bufsz = tmp_size;
1576 			} else {
1577 				FILE *tmp = accum_file;
1578 				accum_file = base_file;
1579 				base_file = tmp;
1580 				rewind(base_file);
1581 				rewind(accum_file);
1582 			}
1583 		}
1584 	}
1585 
1586 done:
1587 	free(base_buf);
1588 	if (accum_buf) {
1589 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1590 		free(accum_buf);
1591 		if (len != accum_size)
1592 			err = got_ferror(outfile, GOT_ERR_IO);
1593 	}
1594 	rewind(outfile);
1595 	if (err == NULL)
1596 		*result_size = accum_size;
1597 	return err;
1598 }
1599 
1600 const struct got_error *
1601 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1602     struct got_delta_chain *deltas, struct got_pack *pack)
1603 {
1604 	const struct got_error *err = NULL;
1605 	struct got_delta *delta;
1606 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1607 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1608 	uint64_t max_size = 0;
1609 	int n = 0;
1610 
1611 	*outbuf = NULL;
1612 	*outlen = 0;
1613 
1614 	if (STAILQ_EMPTY(&deltas->entries))
1615 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1616 
1617 	/* Deltas are ordered in ascending order. */
1618 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1619 		uint8_t *delta_buf = NULL;
1620 		uint64_t base_size, result_size = 0;
1621 		int cached = 1;
1622 		if (n == 0) {
1623 			off_t delta_data_offset;
1624 
1625 			/* Plain object types are the delta base. */
1626 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1627 			    delta->type != GOT_OBJ_TYPE_TREE &&
1628 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1629 			    delta->type != GOT_OBJ_TYPE_TAG) {
1630 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1631 				goto done;
1632 			}
1633 
1634 			delta_data_offset = delta->offset + delta->tslen;
1635 			if (delta_data_offset >= pack->filesize) {
1636 				err = got_error(GOT_ERR_PACK_OFFSET);
1637 				goto done;
1638 			}
1639 
1640 			if (delta->size > max_size)
1641 				max_size = delta->size;
1642 
1643 			if (pack->map) {
1644 				size_t mapoff;
1645 
1646 				if (delta_data_offset > SIZE_MAX) {
1647 					return got_error_fmt(GOT_ERR_RANGE,
1648 					    "delta %lld offset would "
1649 					    "overflow size_t",
1650 					    (long long)delta_data_offset);
1651 				}
1652 
1653 				mapoff = delta_data_offset;
1654 				err = got_inflate_to_mem_mmap(&base_buf,
1655 				    &base_bufsz, NULL, NULL, pack->map,
1656 				    mapoff, pack->filesize - mapoff);
1657 			} else {
1658 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1659 				    == -1) {
1660 					err = got_error_from_errno("lseek");
1661 					goto done;
1662 				}
1663 				err = got_inflate_to_mem_fd(&base_buf,
1664 				    &base_bufsz, NULL, NULL, max_size,
1665 				    pack->fd);
1666 			}
1667 			if (err)
1668 				goto done;
1669 			n++;
1670 			continue;
1671 		}
1672 
1673 		if (pack->delta_cache) {
1674 			got_delta_cache_get(&delta_buf, &delta_len,
1675 			    pack->delta_cache, delta->data_offset);
1676 		}
1677 		if (delta_buf == NULL) {
1678 			cached = 0;
1679 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1680 			    delta->data_offset, pack);
1681 			if (err)
1682 				goto done;
1683 		}
1684 		if (pack->delta_cache && !cached) {
1685 			err = got_delta_cache_add(pack->delta_cache,
1686 			    delta->data_offset, delta_buf, delta_len);
1687 			if (err == NULL)
1688 				cached = 1;
1689 			else if (err->code != GOT_ERR_NO_SPACE) {
1690 				free(delta_buf);
1691 				goto done;
1692 			}
1693 		}
1694 
1695 		err = got_delta_get_sizes(&base_size, &result_size,
1696 		    delta_buf, delta_len);
1697 		if (err) {
1698 			if (!cached)
1699 				free(delta_buf);
1700 			goto done;
1701 		}
1702 		if (base_size > max_size)
1703 			max_size = base_size;
1704 		if (result_size > max_size)
1705 			max_size = result_size;
1706 
1707 		if (max_size > base_bufsz) {
1708 			uint8_t *p = realloc(base_buf, max_size);
1709 			if (p == NULL) {
1710 				err = got_error_from_errno("realloc");
1711 				if (!cached)
1712 					free(delta_buf);
1713 				goto done;
1714 			}
1715 			base_buf = p;
1716 			base_bufsz = max_size;
1717 		}
1718 
1719 		if (max_size > accum_bufsz) {
1720 			uint8_t *p = realloc(accum_buf, max_size);
1721 			if (p == NULL) {
1722 				err = got_error_from_errno("realloc");
1723 				if (!cached)
1724 					free(delta_buf);
1725 				goto done;
1726 			}
1727 			accum_buf = p;
1728 			accum_bufsz = max_size;
1729 		}
1730 
1731 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1732 		    delta_buf, delta_len, accum_buf,
1733 		    &accum_size, max_size);
1734 		if (!cached)
1735 			free(delta_buf);
1736 		n++;
1737 		if (err)
1738 			goto done;
1739 
1740 		if (n < deltas->nentries) {
1741 			/* Accumulated delta becomes the new base. */
1742 			uint8_t *tmp = accum_buf;
1743 			size_t tmp_size = accum_bufsz;
1744 			accum_buf = base_buf;
1745 			accum_bufsz = base_bufsz;
1746 			base_buf = tmp;
1747 			base_bufsz = tmp_size;
1748 		}
1749 	}
1750 
1751 done:
1752 	free(base_buf);
1753 	if (err) {
1754 		free(accum_buf);
1755 		*outbuf = NULL;
1756 		*outlen = 0;
1757 	} else {
1758 		*outbuf = accum_buf;
1759 		*outlen = accum_size;
1760 	}
1761 	return err;
1762 }
1763 
1764 const struct got_error *
1765 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1766     FILE *outfile, FILE *base_file, FILE *accum_file)
1767 {
1768 	const struct got_error *err = NULL;
1769 
1770 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1771 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1772 
1773 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1774 		if (obj->pack_offset >= pack->filesize)
1775 			return got_error(GOT_ERR_PACK_OFFSET);
1776 
1777 		if (pack->map) {
1778 			size_t mapoff;
1779 
1780 			if (obj->pack_offset > SIZE_MAX) {
1781 				return got_error_fmt(GOT_ERR_RANGE,
1782 				    "pack offset %lld would overflow size_t",
1783 				    (long long)obj->pack_offset);
1784 			}
1785 
1786 			mapoff = obj->pack_offset;
1787 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1788 			    pack->map, mapoff, pack->filesize - mapoff,
1789 			    outfile);
1790 		} else {
1791 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1792 				return got_error_from_errno("lseek");
1793 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1794 			    pack->fd, outfile);
1795 		}
1796 	} else
1797 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1798 		    &obj->deltas, pack, outfile, base_file, accum_file);
1799 
1800 	return err;
1801 }
1802 
1803 const struct got_error *
1804 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1805     struct got_object *obj, struct got_pack *pack)
1806 {
1807 	const struct got_error *err = NULL;
1808 
1809 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1810 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1811 
1812 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1813 		if (obj->pack_offset >= pack->filesize)
1814 			return got_error(GOT_ERR_PACK_OFFSET);
1815 		if (pack->map) {
1816 			size_t mapoff;
1817 
1818 			if (obj->pack_offset > SIZE_MAX) {
1819 				return got_error_fmt(GOT_ERR_RANGE,
1820 				    "pack offset %lld would overflow size_t",
1821 				    (long long)obj->pack_offset);
1822 			}
1823 
1824 			mapoff = obj->pack_offset;
1825 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1826 			    pack->map, mapoff, pack->filesize - mapoff);
1827 		} else {
1828 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1829 				return got_error_from_errno("lseek");
1830 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1831 			    obj->size, pack->fd);
1832 		}
1833 	} else
1834 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1835 		    pack);
1836 
1837 	return err;
1838 }
1839 
1840 static const struct got_error *
1841 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1842     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1843     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1844 {
1845 	const struct got_error *err = NULL;
1846 
1847 	/* Validate decompression and obtain the decompressed size. */
1848 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1849 	    delta_data_offset, pack);
1850 	if (err)
1851 		return err;
1852 
1853 	/* Read delta base/result sizes from head of delta stream. */
1854 	err = got_delta_get_sizes(base_size, result_size,
1855 	    *delta_buf, *delta_len);
1856 	if (err)
1857 		goto done;
1858 
1859 	/* Discard decompressed delta and read it again in compressed form. */
1860 	free(*delta_buf);
1861 	*delta_buf = malloc(*delta_len_compressed);
1862 	if (*delta_buf == NULL) {
1863 		err = got_error_from_errno("malloc");
1864 		goto done;
1865 	}
1866 	if (pack->map) {
1867 		if (delta_data_offset >= pack->filesize) {
1868 			err = got_error(GOT_ERR_PACK_OFFSET);
1869 			goto done;
1870 		}
1871 		memcpy(*delta_buf, pack->map + delta_data_offset,
1872 		    *delta_len_compressed);
1873 	} else {
1874 		ssize_t n;
1875 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1876 			err = got_error_from_errno("lseek");
1877 			goto done;
1878 		}
1879 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1880 		if (n < 0) {
1881 			err = got_error_from_errno("read");
1882 			goto done;
1883 		} else if (n != *delta_len_compressed) {
1884 			err = got_error(GOT_ERR_IO);
1885 			goto done;
1886 		}
1887 	}
1888 done:
1889 	if (err) {
1890 		free(*delta_buf);
1891 		*delta_buf = NULL;
1892 		*delta_len = 0;
1893 		*delta_len_compressed = 0;
1894 		*base_size = 0;
1895 		*result_size = 0;
1896 	}
1897 	return err;
1898 }
1899 
1900 const struct got_error *
1901 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1902     size_t *delta_compressed_size, off_t *delta_offset,
1903     off_t *delta_data_offset, off_t *base_offset,
1904     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1905     struct got_pack *pack, struct got_packidx *packidx, int idx)
1906 {
1907 	const struct got_error *err = NULL;
1908 	off_t offset;
1909 	uint8_t type;
1910 	uint64_t size;
1911 	size_t tslen, delta_hdrlen;
1912 
1913 	*delta_buf = NULL;
1914 	*delta_size = 0;
1915 	*delta_compressed_size = 0;
1916 	*delta_offset = 0;
1917 	*delta_data_offset = 0;
1918 	*base_offset = 0;
1919 	*base_size = 0;
1920 	*result_size = 0;
1921 
1922 	offset = got_packidx_get_object_offset(packidx, idx);
1923 	if (offset == -1)
1924 		return got_error(GOT_ERR_BAD_PACKIDX);
1925 
1926 	if (offset >= pack->filesize)
1927 		return got_error(GOT_ERR_PACK_OFFSET);
1928 
1929 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1930 	    pack, offset);
1931 	if (err)
1932 		return err;
1933 
1934 	if (tslen + size < tslen || offset + size < size ||
1935 	    tslen + offset < tslen)
1936 		return got_error(GOT_ERR_PACK_OFFSET);
1937 
1938 	switch (type) {
1939 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1940 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1941 		    pack, offset, tslen);
1942 		if (err)
1943 			return err;
1944 		break;
1945 	case GOT_OBJ_TYPE_REF_DELTA:
1946 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1947 		if (err)
1948 			return err;
1949 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1950 		break;
1951 	default:
1952 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1953 		    "non-delta object type %d found at offset %lld",
1954 		    type, (long long)offset);
1955 	}
1956 
1957 	if (tslen + delta_hdrlen < delta_hdrlen ||
1958 	    offset + delta_hdrlen < delta_hdrlen)
1959 		return got_error(GOT_ERR_BAD_DELTA);
1960 
1961 	*delta_data_offset = offset + tslen + delta_hdrlen;
1962 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
1963 	    base_size, result_size, *delta_data_offset, pack, packidx);
1964 	if (err)
1965 		return err;
1966 
1967 	if (*delta_size != size) {
1968 		err = got_error(GOT_ERR_BAD_DELTA);
1969 		goto done;
1970 	}
1971 
1972 	*delta_offset = offset;
1973 done:
1974 	if (err) {
1975 		free(*delta_buf);
1976 		*delta_buf = NULL;
1977 		*delta_size = 0;
1978 		*delta_compressed_size = 0;
1979 		*delta_offset = 0;
1980 		*base_offset = 0;
1981 		*base_size = 0;
1982 		*result_size = 0;
1983 	}
1984 	return err;
1985 }