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