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 <unistd.h>
33 #include <zlib.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_path.h"
38 
39 #include "got_lib_hash.h"
40 #include "got_lib_delta.h"
41 #include "got_lib_delta_cache.h"
42 #include "got_lib_inflate.h"
43 #include "got_lib_object.h"
44 #include "got_lib_object_parse.h"
45 #include "got_lib_privsep.h"
46 #include "got_lib_pack.h"
47 
48 #ifndef nitems
49 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
50 #endif
51 
52 #ifndef MIN
53 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
54 #endif
55 
56 static const struct got_error *
57 verify_fanout_table(uint32_t *fanout_table)
58 {
59 	int i;
60 
61 	for (i = 0; i < 0xff - 1; i++) {
62 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
63 			return got_error(GOT_ERR_BAD_PACKIDX);
64 	}
65 
66 	return NULL;
67 }
68 
69 const struct got_error *
70 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
71 {
72 	const struct got_error *err = NULL;
73 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
74 	struct got_packidx_v2_hdr *h;
75 	struct got_hash ctx;
76 	uint8_t hash[GOT_HASH_DIGEST_MAXLEN];
77 	size_t nobj, len_fanout, len_ids, offset, remain;
78 	ssize_t n;
79 	int i;
80 
81 	got_hash_init(&ctx, algo);
82 
83 	h = &p->hdr;
84 	offset = 0;
85 	remain = p->len;
86 
87 	if (remain < sizeof(*h->magic)) {
88 		err = got_error(GOT_ERR_BAD_PACKIDX);
89 		goto done;
90 	}
91 	if (p->map)
92 		h->magic = (uint32_t *)(p->map + offset);
93 	else {
94 		h->magic = malloc(sizeof(*h->magic));
95 		if (h->magic == NULL) {
96 			err = got_error_from_errno("malloc");
97 			goto done;
98 		}
99 		n = read(p->fd, h->magic, sizeof(*h->magic));
100 		if (n < 0) {
101 			err = got_error_from_errno("read");
102 			goto done;
103 		} else if (n != sizeof(*h->magic)) {
104 			err = got_error(GOT_ERR_BAD_PACKIDX);
105 			goto done;
106 		}
107 	}
108 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
109 		err = got_error(GOT_ERR_BAD_PACKIDX);
110 		goto done;
111 	}
112 	offset += sizeof(*h->magic);
113 	remain -= sizeof(*h->magic);
114 
115 	if (verify)
116 		got_hash_update(&ctx, h->magic, sizeof(*h->magic));
117 
118 	if (remain < sizeof(*h->version)) {
119 		err = got_error(GOT_ERR_BAD_PACKIDX);
120 		goto done;
121 	}
122 	if (p->map)
123 		h->version = (uint32_t *)(p->map + offset);
124 	else {
125 		h->version = malloc(sizeof(*h->version));
126 		if (h->version == NULL) {
127 			err = got_error_from_errno("malloc");
128 			goto done;
129 		}
130 		n = read(p->fd, h->version, sizeof(*h->version));
131 		if (n < 0) {
132 			err = got_error_from_errno("read");
133 			goto done;
134 		} else if (n != sizeof(*h->version)) {
135 			err = got_error(GOT_ERR_BAD_PACKIDX);
136 			goto done;
137 		}
138 	}
139 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
140 		err = got_error(GOT_ERR_BAD_PACKIDX);
141 		goto done;
142 	}
143 	offset += sizeof(*h->version);
144 	remain -= sizeof(*h->version);
145 
146 	if (verify)
147 		got_hash_update(&ctx, h->version, sizeof(*h->version));
148 
149 	len_fanout =
150 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
151 	if (remain < len_fanout) {
152 		err = got_error(GOT_ERR_BAD_PACKIDX);
153 		goto done;
154 	}
155 	if (p->map)
156 		h->fanout_table = (uint32_t *)(p->map + offset);
157 	else {
158 		h->fanout_table = malloc(len_fanout);
159 		if (h->fanout_table == NULL) {
160 			err = got_error_from_errno("malloc");
161 			goto done;
162 		}
163 		n = read(p->fd, h->fanout_table, len_fanout);
164 		if (n < 0) {
165 			err = got_error_from_errno("read");
166 			goto done;
167 		} else if (n != len_fanout) {
168 			err = got_error(GOT_ERR_BAD_PACKIDX);
169 			goto done;
170 		}
171 	}
172 	err = verify_fanout_table(h->fanout_table);
173 	if (err)
174 		goto done;
175 	if (verify)
176 		got_hash_update(&ctx, h->fanout_table, len_fanout);
177 	offset += len_fanout;
178 	remain -= len_fanout;
179 
180 	nobj = be32toh(h->fanout_table[0xff]);
181 	len_ids = nobj * sizeof(*h->sorted_ids);
182 	if (len_ids <= nobj || len_ids > remain) {
183 		err = got_error(GOT_ERR_BAD_PACKIDX);
184 		goto done;
185 	}
186 	if (p->map)
187 		h->sorted_ids =
188 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
189 	else {
190 		h->sorted_ids = malloc(len_ids);
191 		if (h->sorted_ids == NULL) {
192 			err = got_error(GOT_ERR_BAD_PACKIDX);
193 			goto done;
194 		}
195 		n = read(p->fd, h->sorted_ids, len_ids);
196 		if (n < 0)
197 			err = got_error_from_errno("read");
198 		else if (n != len_ids) {
199 			err = got_error(GOT_ERR_BAD_PACKIDX);
200 			goto done;
201 		}
202 	}
203 	if (verify)
204 		got_hash_update(&ctx, h->sorted_ids, len_ids);
205 	offset += len_ids;
206 	remain -= len_ids;
207 
208 	if (remain < nobj * sizeof(*h->crc32)) {
209 		err = got_error(GOT_ERR_BAD_PACKIDX);
210 		goto done;
211 	}
212 	if (p->map)
213 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
214 	else {
215 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
216 		if (h->crc32 == NULL) {
217 			err = got_error_from_errno("malloc");
218 			goto done;
219 		}
220 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
221 		if (n < 0)
222 			err = got_error_from_errno("read");
223 		else if (n != nobj * sizeof(*h->crc32)) {
224 			err = got_error(GOT_ERR_BAD_PACKIDX);
225 			goto done;
226 		}
227 	}
228 	if (verify)
229 		got_hash_update(&ctx, h->crc32, nobj * sizeof(*h->crc32));
230 	remain -= nobj * sizeof(*h->crc32);
231 	offset += nobj * sizeof(*h->crc32);
232 
233 	if (remain < nobj * sizeof(*h->offsets)) {
234 		err = got_error(GOT_ERR_BAD_PACKIDX);
235 		goto done;
236 	}
237 	if (p->map)
238 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
239 	else {
240 		h->offsets = malloc(nobj * sizeof(*h->offsets));
241 		if (h->offsets == NULL) {
242 			err = got_error_from_errno("malloc");
243 			goto done;
244 		}
245 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
246 		if (n < 0)
247 			err = got_error_from_errno("read");
248 		else if (n != nobj * sizeof(*h->offsets)) {
249 			err = got_error(GOT_ERR_BAD_PACKIDX);
250 			goto done;
251 		}
252 	}
253 	if (verify)
254 		got_hash_update(&ctx, h->offsets, nobj * sizeof(*h->offsets));
255 	remain -= nobj * sizeof(*h->offsets);
256 	offset += nobj * sizeof(*h->offsets);
257 
258 	/* Large file offsets are contained only in files > 2GB. */
259 	if (verify || packfile_size > 0x7fffffff) {
260 		for (i = 0; i < nobj; i++) {
261 			uint32_t o = h->offsets[i];
262 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
263 				p->nlargeobj++;
264 		}
265 	}
266 	if (p->nlargeobj == 0)
267 		goto checksum;
268 	else if (packfile_size <= 0x7fffffff) {
269 		err = got_error(GOT_ERR_BAD_PACKIDX);
270 		goto done;
271 	}
272 
273 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
274 		err = got_error(GOT_ERR_BAD_PACKIDX);
275 		goto done;
276 	}
277 	if (p->map)
278 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
279 	else {
280 		h->large_offsets = malloc(p->nlargeobj *
281 		    sizeof(*h->large_offsets));
282 		if (h->large_offsets == NULL) {
283 			err = got_error_from_errno("malloc");
284 			goto done;
285 		}
286 		n = read(p->fd, h->large_offsets,
287 		    p->nlargeobj * sizeof(*h->large_offsets));
288 		if (n < 0)
289 			err = got_error_from_errno("read");
290 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
291 			err = got_error(GOT_ERR_BAD_PACKIDX);
292 			goto done;
293 		}
294 	}
295 	if (verify)
296 		got_hash_update(&ctx, h->large_offsets,
297 		    p->nlargeobj * sizeof(*h->large_offsets));
298 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
299 	offset += p->nlargeobj * sizeof(*h->large_offsets);
300 
301 checksum:
302 	if (remain < sizeof(*h->trailer)) {
303 		err = got_error(GOT_ERR_BAD_PACKIDX);
304 		goto done;
305 	}
306 	if (p->map)
307 		h->trailer =
308 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
309 	else {
310 		h->trailer = malloc(sizeof(*h->trailer));
311 		if (h->trailer == NULL) {
312 			err = got_error_from_errno("malloc");
313 			goto done;
314 		}
315 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
316 		if (n < 0)
317 			err = got_error_from_errno("read");
318 		else if (n != sizeof(*h->trailer)) {
319 			err = got_error(GOT_ERR_BAD_PACKIDX);
320 			goto done;
321 		}
322 	}
323 	if (verify) {
324 		got_hash_update(&ctx, h->trailer->packfile_sha1,
325 		    SHA1_DIGEST_LENGTH);
326 		got_hash_final(&ctx, hash);
327 		if (got_hash_cmp(ctx.algo, hash, h->trailer->packidx_sha1)
328 		    != 0)
329 			err = got_error(GOT_ERR_PACKIDX_CSUM);
330 	}
331 done:
332 	return err;
333 }
334 
335 const struct got_error *
336 got_packidx_open(struct got_packidx **packidx,
337     int dir_fd, const char *relpath, int verify)
338 {
339 	const struct got_error *err = NULL;
340 	struct got_packidx *p = NULL;
341 	char *pack_relpath;
342 	struct stat idx_sb, pack_sb;
343 
344 	*packidx = NULL;
345 
346 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
347 	if (err)
348 		return err;
349 
350 	/*
351 	 * Ensure that a corresponding pack file exists.
352 	 * Some Git repositories have this problem. Git seems to ignore
353 	 * the existence of lonely pack index files but we do not.
354 	 */
355 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
356 		if (errno == ENOENT) {
357 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
358 			    "%s", relpath);
359 		} else
360 			err = got_error_from_errno2("fstatat", pack_relpath);
361 		goto done;
362 	}
363 
364 	p = calloc(1, sizeof(*p));
365 	if (p == NULL) {
366 		err = got_error_from_errno("calloc");
367 		goto done;
368 	}
369 
370 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
371 	if (p->fd == -1) {
372 		err = got_error_from_errno2("openat", relpath);
373 		goto done;
374 	}
375 
376 	if (fstat(p->fd, &idx_sb) != 0) {
377 		err = got_error_from_errno2("fstat", relpath);
378 		goto done;
379 	}
380 	p->len = idx_sb.st_size;
381 	if (p->len < sizeof(p->hdr)) {
382 		err = got_error(GOT_ERR_BAD_PACKIDX);
383 		goto done;
384 	}
385 
386 	p->path_packidx = strdup(relpath);
387 	if (p->path_packidx == NULL) {
388 		err = got_error_from_errno("strdup");
389 		goto done;
390 	}
391 
392 #ifndef GOT_PACK_NO_MMAP
393 	if (p->len > 0 && p->len <= SIZE_MAX) {
394 		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
395 		if (p->map == MAP_FAILED) {
396 			if (errno != ENOMEM) {
397 				err = got_error_from_errno("mmap");
398 				goto done;
399 			}
400 			p->map = NULL; /* fall back to read(2) */
401 		}
402 	}
403 #endif
404 
405 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
406 done:
407 	if (err) {
408 		if (p)
409 			got_packidx_close(p);
410 	} else
411 		*packidx = p;
412 	free(pack_relpath);
413 	return err;
414 }
415 
416 const struct got_error *
417 got_packidx_close(struct got_packidx *packidx)
418 {
419 	const struct got_error *err = NULL;
420 
421 	free(packidx->path_packidx);
422 	if (packidx->map) {
423 		if (munmap(packidx->map, packidx->len) == -1)
424 			err = got_error_from_errno("munmap");
425 	} else {
426 		free(packidx->hdr.magic);
427 		free(packidx->hdr.version);
428 		free(packidx->hdr.fanout_table);
429 		free(packidx->hdr.sorted_ids);
430 		free(packidx->hdr.crc32);
431 		free(packidx->hdr.offsets);
432 		free(packidx->hdr.large_offsets);
433 		free(packidx->hdr.trailer);
434 	}
435 	if (close(packidx->fd) == -1 && err == NULL)
436 		err = got_error_from_errno("close");
437 	free(packidx->sorted_offsets);
438 	free(packidx->sorted_large_offsets);
439 	free(packidx);
440 
441 	return err;
442 }
443 
444 const struct got_error *
445 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
446 {
447 	size_t size;
448 
449 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
450 	size = strlen(path_packidx) + 2;
451 	if (size < GOT_PACKFILE_NAMELEN + 1)
452 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
453 
454 	*path_packfile = malloc(size);
455 	if (*path_packfile == NULL)
456 		return got_error_from_errno("malloc");
457 
458 	/* Copy up to and excluding ".idx". */
459 	if (strlcpy(*path_packfile, path_packidx,
460 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
461 		return got_error(GOT_ERR_NO_SPACE);
462 
463 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
464 		return got_error(GOT_ERR_NO_SPACE);
465 
466 	return NULL;
467 }
468 
469 off_t
470 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
471 {
472 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
473 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
474 		uint64_t loffset;
475 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
476 		if (idx < 0 || idx >= packidx->nlargeobj ||
477 		    packidx->hdr.large_offsets == NULL)
478 			return -1;
479 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
480 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
481 	}
482 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
483 }
484 
485 int
486 got_packidx_get_object_idx(struct got_packidx *packidx,
487     struct got_object_id *id)
488 {
489 	u_int8_t id0 = id->sha1[0];
490 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
491 	int left = 0, right = totobj - 1;
492 
493 	if (id0 > 0)
494 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
495 
496 	while (left <= right) {
497 		struct got_packidx_object_id *oid;
498 		int i, cmp;
499 
500 		i = ((left + right) / 2);
501 		oid = &packidx->hdr.sorted_ids[i];
502 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
503 		if (cmp == 0)
504 			return i;
505 		else if (cmp > 0)
506 			left = i + 1;
507 		else if (cmp < 0)
508 			right = i - 1;
509 	}
510 
511 	return -1;
512 }
513 
514 static int
515 offset_cmp(const void *pa, const void *pb)
516 {
517 	const struct got_pack_offset_index *a, *b;
518 
519 	a = (const struct got_pack_offset_index *)pa;
520 	b = (const struct got_pack_offset_index *)pb;
521 
522 	if (a->offset < b->offset)
523 		return -1;
524 	else if (a->offset > b->offset)
525 		return 1;
526 
527 	return 0;
528 }
529 
530 static int
531 large_offset_cmp(const void *pa, const void *pb)
532 {
533 	const struct got_pack_large_offset_index *a, *b;
534 
535 	a = (const struct got_pack_large_offset_index *)pa;
536 	b = (const struct got_pack_large_offset_index *)pb;
537 
538 	if (a->offset < b->offset)
539 		return -1;
540 	else if (a->offset > b->offset)
541 		return 1;
542 
543 	return 0;
544 }
545 
546 static const struct got_error *
547 build_offset_index(struct got_packidx *p)
548 {
549 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
550 	unsigned int i, j, k;
551 
552 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
553 	    sizeof(p->sorted_offsets[0]));
554 	if (p->sorted_offsets == NULL)
555 		return got_error_from_errno("calloc");
556 
557 	if (p->nlargeobj > 0) {
558 		p->sorted_large_offsets = calloc(p->nlargeobj,
559 		    sizeof(p->sorted_large_offsets[0]));
560 		if (p->sorted_large_offsets == NULL)
561 			return got_error_from_errno("calloc");
562 	}
563 
564 	j = 0;
565 	k = 0;
566 	for (i = 0; i < nobj; i++) {
567 		uint32_t offset = be32toh(p->hdr.offsets[i]);
568 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
569 			uint64_t loffset;
570 			uint32_t idx;
571 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
572 			if (idx >= p->nlargeobj ||
573 			    p->nlargeobj == 0 ||
574 			    p->hdr.large_offsets == NULL)
575 				return got_error(GOT_ERR_BAD_PACKIDX);
576 			loffset = be64toh(p->hdr.large_offsets[idx]);
577 			p->sorted_large_offsets[j].offset = loffset;
578 			p->sorted_large_offsets[j].idx = i;
579 			j++;
580 		} else {
581 			p->sorted_offsets[k].offset = offset;
582 			p->sorted_offsets[k].idx = i;
583 			k++;
584 		}
585 	}
586 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
587 		return got_error(GOT_ERR_BAD_PACKIDX);
588 
589 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
590 	    sizeof(p->sorted_offsets[0]), offset_cmp);
591 
592 	if (p->sorted_large_offsets)
593 		qsort(p->sorted_large_offsets, p->nlargeobj,
594 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
595 
596 	return NULL;
597 }
598 
599 const struct got_error *
600 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
601 {
602 	const struct got_error *err;
603 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
604 	int i, left, right;
605 
606 	*idx = -1;
607 
608 	if (packidx->sorted_offsets == NULL) {
609 		err = build_offset_index(packidx);
610 		if (err)
611 			return err;
612 	}
613 
614 	if (offset >= 0x7fffffff) {
615 		uint64_t lo;
616 		left = 0, right = packidx->nlargeobj - 1;
617 		while (left <= right) {
618 			i = ((left + right) / 2);
619 			lo = packidx->sorted_large_offsets[i].offset;
620 			if (lo == offset) {
621 				*idx = packidx->sorted_large_offsets[i].idx;
622 				break;
623 			} else if (offset > lo)
624 				left = i + 1;
625 			else if (offset < lo)
626 				right = i - 1;
627 		}
628 	} else {
629 		uint32_t o;
630 		left = 0, right = totobj - packidx->nlargeobj - 1;
631 		while (left <= right) {
632 			i = ((left + right) / 2);
633 			o = packidx->sorted_offsets[i].offset;
634 			if (o == offset) {
635 				*idx = packidx->sorted_offsets[i].idx;
636 				break;
637 			} else if (offset > o)
638 				left = i + 1;
639 			else if (offset < o)
640 				right = i - 1;
641 		}
642 	}
643 
644 	return NULL;
645 }
646 
647 const struct got_error *
648 got_packidx_get_object_id(struct got_object_id *id,
649     struct got_packidx *packidx, int idx)
650 {
651 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
652 	struct got_packidx_object_id *oid;
653 
654 	if (idx < 0 || idx >= totobj)
655 		return got_error(GOT_ERR_NO_OBJ);
656 
657 	oid = &packidx->hdr.sorted_ids[idx];
658 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
659 	return NULL;
660 }
661 
662 const struct got_error *
663 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
664     struct got_packidx *packidx, const char *id_str_prefix)
665 {
666 	const struct got_error *err = NULL;
667 	u_int8_t id0;
668 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
669 	char hex[3];
670 	size_t prefix_len = strlen(id_str_prefix);
671 	struct got_packidx_object_id *oid;
672 	uint32_t i = 0;
673 
674 	STAILQ_INIT(matched_ids);
675 
676 	if (prefix_len < 2)
677 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
678 
679 	hex[0] = id_str_prefix[0];
680 	hex[1] = id_str_prefix[1];
681 	hex[2] = '\0';
682 	if (!got_parse_xdigit(&id0, hex))
683 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
684 
685 	if (id0 > 0)
686 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
687 	oid = &packidx->hdr.sorted_ids[i];
688 	while (i < totobj && oid->sha1[0] == id0) {
689 		char id_str[SHA1_DIGEST_STRING_LENGTH];
690 		struct got_object_qid *qid;
691 		int cmp;
692 
693 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
694 		        return got_error(GOT_ERR_NO_SPACE);
695 
696 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
697 		if (cmp < 0) {
698 			oid = &packidx->hdr.sorted_ids[++i];
699 			continue;
700 		} else if (cmp > 0)
701 			break;
702 
703 		err = got_object_qid_alloc_partial(&qid);
704 		if (err)
705 			break;
706 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
707 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
708 
709 		oid = &packidx->hdr.sorted_ids[++i];
710 	}
711 
712 	if (err)
713 		got_object_id_queue_free(matched_ids);
714 	return err;
715 }
716 
717 static void
718 set_max_datasize(void)
719 {
720 	struct rlimit rl;
721 
722 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
723 		return;
724 
725 	rl.rlim_cur = rl.rlim_max;
726 	setrlimit(RLIMIT_DATA, &rl);
727 }
728 
729 const struct got_error *
730 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
731 {
732 	const struct got_error *err = NULL;
733 	int imsg_fds[2];
734 	pid_t pid;
735 	struct imsgbuf *ibuf;
736 
737 	ibuf = calloc(1, sizeof(*ibuf));
738 	if (ibuf == NULL)
739 		return got_error_from_errno("calloc");
740 
741 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
742 	if (pack->privsep_child == NULL) {
743 		err = got_error_from_errno("calloc");
744 		free(ibuf);
745 		return err;
746 	}
747 	pack->child_has_tempfiles = 0;
748 	pack->child_has_delta_outfd = 0;
749 
750 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
751 		err = got_error_from_errno("socketpair");
752 		goto done;
753 	}
754 
755 	pid = fork();
756 	if (pid == -1) {
757 		err = got_error_from_errno("fork");
758 		goto done;
759 	} else if (pid == 0) {
760 		set_max_datasize();
761 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
762 		    pack->path_packfile);
763 		/* not reached */
764 	}
765 
766 	if (close(imsg_fds[1]) == -1)
767 		return got_error_from_errno("close");
768 	pack->privsep_child->imsg_fd = imsg_fds[0];
769 	pack->privsep_child->pid = pid;
770 	imsg_init(ibuf, imsg_fds[0]);
771 	pack->privsep_child->ibuf = ibuf;
772 
773 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
774 	if (err) {
775 		const struct got_error *child_err;
776 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
777 		child_err = got_privsep_wait_for_child(
778 		    pack->privsep_child->pid);
779 		if (child_err && err == NULL)
780 			err = child_err;
781 	}
782 done:
783 	if (err) {
784 		free(ibuf);
785 		free(pack->privsep_child);
786 		pack->privsep_child = NULL;
787 	}
788 	return err;
789 }
790 
791 static const struct got_error *
792 pack_stop_privsep_child(struct got_pack *pack)
793 {
794 	const struct got_error *err = NULL, *close_err = NULL;
795 
796 	if (pack->privsep_child == NULL)
797 		return NULL;
798 
799 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
800 	if (err)
801 		return err;
802 	if (close(pack->privsep_child->imsg_fd) == -1)
803 		close_err = got_error_from_errno("close");
804 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
805 	if (close_err && err == NULL)
806 		err = close_err;
807 	imsg_clear(pack->privsep_child->ibuf);
808 	free(pack->privsep_child->ibuf);
809 	free(pack->privsep_child);
810 	pack->privsep_child = NULL;
811 	return err;
812 }
813 
814 const struct got_error *
815 got_pack_close(struct got_pack *pack)
816 {
817 	const struct got_error *err = NULL;
818 
819 	err = pack_stop_privsep_child(pack);
820 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
821 		err = got_error_from_errno("munmap");
822 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
823 		err = got_error_from_errno("close");
824 	pack->fd = -1;
825 	free(pack->path_packfile);
826 	pack->path_packfile = NULL;
827 	pack->filesize = 0;
828 	if (pack->delta_cache) {
829 		got_delta_cache_free(pack->delta_cache);
830 		pack->delta_cache = NULL;
831 	}
832 
833 	/*
834 	 * Leave accumfd and basefd alone. They are managed by the
835 	 * repository layer and can be reused.
836 	 */
837 
838 	return err;
839 }
840 
841 const struct got_error *
842 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
843     struct got_pack *pack, off_t offset)
844 {
845 	uint8_t t = 0;
846 	uint64_t s = 0;
847 	uint8_t sizeN;
848 	size_t mapoff = 0;
849 	int i = 0;
850 
851 	*len = 0;
852 
853 	if (offset >= pack->filesize)
854 		return got_error(GOT_ERR_PACK_OFFSET);
855 
856 	if (pack->map) {
857 		if (offset > SIZE_MAX) {
858 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
859 			    "offset %lld overflows size_t",
860 			    (long long)offset);
861 		}
862 
863 		mapoff = (size_t)offset;
864 	} else {
865 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
866 			return got_error_from_errno("lseek");
867 	}
868 
869 	do {
870 		/* We do not support size values which don't fit in 64 bit. */
871 		if (i > 9)
872 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
873 			    "packfile offset %lld", (long long)offset);
874 
875 		if (pack->map) {
876 			if (mapoff + sizeof(sizeN) >= pack->filesize)
877 				return got_error(GOT_ERR_BAD_PACKFILE);
878 			sizeN = *(pack->map + mapoff);
879 			mapoff += sizeof(sizeN);
880 		} else {
881 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
882 			if (n < 0)
883 				return got_error_from_errno("read");
884 			if (n != sizeof(sizeN))
885 				return got_error(GOT_ERR_BAD_PACKFILE);
886 		}
887 		*len += sizeof(sizeN);
888 
889 		if (i == 0) {
890 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
891 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
892 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
893 		} else {
894 			size_t shift = 4 + 7 * (i - 1);
895 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
896 		}
897 		i++;
898 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
899 
900 	*type = t;
901 	*size = s;
902 	return NULL;
903 }
904 
905 static const struct got_error *
906 open_plain_object(struct got_object **obj, struct got_object_id *id,
907     uint8_t type, off_t offset, size_t size, int idx)
908 {
909 	*obj = calloc(1, sizeof(**obj));
910 	if (*obj == NULL)
911 		return got_error_from_errno("calloc");
912 
913 	(*obj)->type = type;
914 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
915 	(*obj)->pack_idx = idx;
916 	(*obj)->hdrlen = 0;
917 	(*obj)->size = size;
918 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
919 	(*obj)->pack_offset = offset;
920 
921 	return NULL;
922 }
923 
924 static const struct got_error *
925 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
926     off_t delta_offset)
927 {
928 	int64_t o = 0;
929 	uint8_t offN;
930 	int i = 0;
931 
932 	*offset = 0;
933 	*len = 0;
934 
935 	do {
936 		/* We do not support offset values which don't fit in 64 bit. */
937 		if (i > 8)
938 			return got_error(GOT_ERR_NO_SPACE);
939 
940 		if (pack->map) {
941 			size_t mapoff;
942 
943 			if (delta_offset + *len > SIZE_MAX) {
944 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
945 				    "mapoff %lld would overflow size_t",
946 				    (long long)delta_offset + *len);
947 			}
948 
949 			mapoff = (size_t)delta_offset + *len;
950 			if (mapoff + sizeof(offN) >= pack->filesize)
951 				return got_error(GOT_ERR_PACK_OFFSET);
952 			offN = *(pack->map + mapoff);
953 		} else {
954 			ssize_t n;
955 			n = read(pack->fd, &offN, sizeof(offN));
956 			if (n < 0)
957 				return got_error_from_errno("read");
958 			if (n != sizeof(offN))
959 				return got_error(GOT_ERR_BAD_PACKFILE);
960 		}
961 		*len += sizeof(offN);
962 
963 		if (i == 0)
964 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
965 		else {
966 			o++;
967 			o <<= 7;
968 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
969 		}
970 		i++;
971 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
972 
973 	*offset = o;
974 	return NULL;
975 }
976 
977 const struct got_error *
978 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
979     struct got_pack *pack, off_t offset, size_t tslen)
980 {
981 	const struct got_error *err;
982 	int64_t negoffset;
983 	size_t negofflen;
984 
985 	*len = 0;
986 
987 	err = parse_negative_offset(&negoffset, &negofflen, pack,
988 	    offset + tslen);
989 	if (err)
990 		return err;
991 
992 	/* Compute the base object's offset (must be in the same pack file). */
993 	*base_offset = (offset - negoffset);
994 	if (*base_offset <= 0)
995 		return got_error(GOT_ERR_BAD_PACKFILE);
996 
997 	*len = negofflen;
998 	return NULL;
999 }
1000 
1001 static const struct got_error *
1002 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1003     size_t *delta_compressed_len, size_t delta_data_offset,
1004     struct got_pack *pack)
1005 {
1006 	const struct got_error *err = NULL;
1007 	size_t consumed = 0;
1008 
1009 	if (pack->map) {
1010 		if (delta_data_offset >= pack->filesize)
1011 			return got_error(GOT_ERR_PACK_OFFSET);
1012 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1013 		    &consumed, NULL, pack->map, delta_data_offset,
1014 		    pack->filesize - delta_data_offset);
1015 		if (err)
1016 			return err;
1017 	} else {
1018 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1019 			return got_error_from_errno("lseek");
1020 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1021 		    &consumed, NULL, 0, pack->fd);
1022 		if (err)
1023 			return err;
1024 	}
1025 
1026 	if (delta_compressed_len)
1027 		*delta_compressed_len = consumed;
1028 
1029 	return NULL;
1030 }
1031 
1032 static const struct got_error *
1033 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1034     int delta_type, size_t delta_size, off_t delta_data_offset)
1035 {
1036 	struct got_delta *delta;
1037 
1038 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1039 	    delta_data_offset);
1040 	if (delta == NULL)
1041 		return got_error_from_errno("got_delta_open");
1042 	/* delta is freed in got_object_close() */
1043 	deltas->nentries++;
1044 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1045 	return NULL;
1046 }
1047 
1048 static const struct got_error *
1049 resolve_offset_delta(struct got_delta_chain *deltas,
1050     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1051     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1052 {
1053 	const struct got_error *err;
1054 	off_t base_offset;
1055 	uint8_t base_type;
1056 	uint64_t base_size;
1057 	size_t base_tslen;
1058 	off_t delta_data_offset;
1059 	size_t consumed;
1060 
1061 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1062 	    delta_offset, tslen);
1063 	if (err)
1064 		return err;
1065 
1066 	delta_data_offset = delta_offset + tslen + consumed;
1067 	if (delta_data_offset >= pack->filesize)
1068 		return got_error(GOT_ERR_PACK_OFFSET);
1069 
1070 	if (pack->map == NULL) {
1071 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1072 		if (delta_data_offset == -1)
1073 			return got_error_from_errno("lseek");
1074 	}
1075 
1076 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1077 	    delta_data_offset);
1078 	if (err)
1079 		return err;
1080 
1081 	/* An offset delta must be in the same packfile. */
1082 	if (base_offset >= pack->filesize)
1083 		return got_error(GOT_ERR_PACK_OFFSET);
1084 
1085 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1086 	    &base_tslen, pack, base_offset);
1087 	if (err)
1088 		return err;
1089 
1090 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1091 	    base_tslen, base_type, base_size, recursion - 1);
1092 }
1093 
1094 const struct got_error *
1095 got_pack_parse_ref_delta(struct got_object_id *id,
1096     struct got_pack *pack, off_t delta_offset, int tslen)
1097 {
1098 	if (pack->map) {
1099 		size_t mapoff;
1100 
1101 		if (delta_offset + tslen > SIZE_MAX) {
1102 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1103 			    "mapoff %lld would overflow size_t",
1104 			    (long long)delta_offset + tslen);
1105 		}
1106 
1107 		mapoff = delta_offset + tslen;
1108 		if (mapoff + sizeof(*id) >= pack->filesize)
1109 			return got_error(GOT_ERR_PACK_OFFSET);
1110 		memcpy(id, pack->map + mapoff, sizeof(*id));
1111 	} else {
1112 		ssize_t n;
1113 		n = read(pack->fd, id, sizeof(*id));
1114 		if (n < 0)
1115 			return got_error_from_errno("read");
1116 		if (n != sizeof(*id))
1117 			return got_error(GOT_ERR_BAD_PACKFILE);
1118 	}
1119 
1120 	return NULL;
1121 }
1122 
1123 static const struct got_error *
1124 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1125     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1126     size_t delta_size, unsigned int recursion)
1127 {
1128 	const struct got_error *err;
1129 	struct got_object_id id;
1130 	int idx;
1131 	off_t base_offset;
1132 	uint8_t base_type;
1133 	uint64_t base_size;
1134 	size_t base_tslen;
1135 	off_t delta_data_offset;
1136 
1137 	if (delta_offset + tslen >= pack->filesize)
1138 		return got_error(GOT_ERR_PACK_OFFSET);
1139 
1140 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1141 	if (err)
1142 		return err;
1143 	if (pack->map) {
1144 		delta_data_offset = delta_offset + tslen + SHA1_DIGEST_LENGTH;
1145 	} else {
1146 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1147 		if (delta_data_offset == -1)
1148 			return got_error_from_errno("lseek");
1149 	}
1150 
1151 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1152 	    delta_data_offset);
1153 	if (err)
1154 		return err;
1155 
1156 	/* Delta base must be in the same pack file. */
1157 	idx = got_packidx_get_object_idx(packidx, &id);
1158 	if (idx == -1)
1159 		return got_error(GOT_ERR_NO_OBJ);
1160 
1161 	base_offset = got_packidx_get_object_offset(packidx, idx);
1162 	if (base_offset == -1)
1163 		return got_error(GOT_ERR_BAD_PACKIDX);
1164 
1165 	if (base_offset >= pack->filesize)
1166 		return got_error(GOT_ERR_PACK_OFFSET);
1167 
1168 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1169 	    &base_tslen, pack, base_offset);
1170 	if (err)
1171 		return err;
1172 
1173 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1174 	    base_tslen, base_type, base_size, recursion - 1);
1175 }
1176 
1177 const struct got_error *
1178 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1179     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1180     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1181 {
1182 	const struct got_error *err = NULL;
1183 
1184 	if (--recursion == 0)
1185 		return got_error(GOT_ERR_RECURSION);
1186 
1187 	switch (delta_type) {
1188 	case GOT_OBJ_TYPE_COMMIT:
1189 	case GOT_OBJ_TYPE_TREE:
1190 	case GOT_OBJ_TYPE_BLOB:
1191 	case GOT_OBJ_TYPE_TAG:
1192 		/* Plain types are the final delta base. Recursion ends. */
1193 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1194 		    delta_size, 0);
1195 		break;
1196 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1197 		err = resolve_offset_delta(deltas, packidx, pack,
1198 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1199 		break;
1200 	case GOT_OBJ_TYPE_REF_DELTA:
1201 		err = resolve_ref_delta(deltas, packidx, pack,
1202 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1203 		break;
1204 	default:
1205 		return got_error(GOT_ERR_OBJ_TYPE);
1206 	}
1207 
1208 	return err;
1209 }
1210 
1211 static const struct got_error *
1212 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1213     struct got_pack *pack, struct got_object_id *id, off_t offset,
1214     size_t tslen, int delta_type, size_t delta_size, int idx)
1215 {
1216 	const struct got_error *err = NULL;
1217 	int resolved_type;
1218 
1219 	*obj = calloc(1, sizeof(**obj));
1220 	if (*obj == NULL)
1221 		return got_error_from_errno("calloc");
1222 
1223 	(*obj)->flags = 0;
1224 	(*obj)->hdrlen = 0;
1225 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1226 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1227 	(*obj)->pack_offset = offset + tslen;
1228 
1229 	STAILQ_INIT(&(*obj)->deltas.entries);
1230 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1231 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1232 	(*obj)->pack_idx = idx;
1233 
1234 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1235 	    offset, tslen, delta_type, delta_size,
1236 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1237 	if (err)
1238 		goto done;
1239 
1240 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1241 	if (err)
1242 		goto done;
1243 	(*obj)->type = resolved_type;
1244 done:
1245 	if (err) {
1246 		got_object_close(*obj);
1247 		*obj = NULL;
1248 	}
1249 	return err;
1250 }
1251 
1252 const struct got_error *
1253 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1254     struct got_packidx *packidx, int idx, struct got_object_id *id)
1255 {
1256 	const struct got_error *err = NULL;
1257 	off_t offset;
1258 	uint8_t type;
1259 	uint64_t size;
1260 	size_t tslen;
1261 
1262 	*obj = NULL;
1263 
1264 	offset = got_packidx_get_object_offset(packidx, idx);
1265 	if (offset == -1)
1266 		return got_error(GOT_ERR_BAD_PACKIDX);
1267 
1268 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1269 	    pack, offset);
1270 	if (err)
1271 		return err;
1272 
1273 	switch (type) {
1274 	case GOT_OBJ_TYPE_COMMIT:
1275 	case GOT_OBJ_TYPE_TREE:
1276 	case GOT_OBJ_TYPE_BLOB:
1277 	case GOT_OBJ_TYPE_TAG:
1278 		err = open_plain_object(obj, id, type, offset + tslen,
1279 		    size, idx);
1280 		break;
1281 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1282 	case GOT_OBJ_TYPE_REF_DELTA:
1283 		err = open_delta_object(obj, packidx, pack, id, offset,
1284 		    tslen, type, size, idx);
1285 		break;
1286 	default:
1287 		err = got_error(GOT_ERR_OBJ_TYPE);
1288 		break;
1289 	}
1290 
1291 	return err;
1292 }
1293 
1294 const struct got_error *
1295 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1296     struct got_delta_chain *deltas, struct got_pack *pack)
1297 {
1298 	struct got_delta *delta;
1299 	uint64_t base_size = 0, result_size = 0;
1300 
1301 	*max_size = 0;
1302 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1303 		/* Plain object types are the delta base. */
1304 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1305 		    delta->type != GOT_OBJ_TYPE_TREE &&
1306 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1307 		    delta->type != GOT_OBJ_TYPE_TAG) {
1308 			const struct got_error *err;
1309 			uint8_t *delta_buf = NULL;
1310 			size_t delta_len;
1311 			int cached = 1;
1312 
1313 			if (pack->delta_cache) {
1314 				got_delta_cache_get(&delta_buf, &delta_len,
1315 				    pack->delta_cache, delta->data_offset);
1316 			}
1317 			if (delta_buf == NULL) {
1318 				cached = 0;
1319 				err = read_delta_data(&delta_buf, &delta_len,
1320 				    NULL, delta->data_offset, pack);
1321 				if (err)
1322 					return err;
1323 			}
1324 			if (pack->delta_cache && !cached) {
1325 				err = got_delta_cache_add(pack->delta_cache,
1326 				    delta->data_offset, delta_buf, delta_len);
1327 				if (err == NULL)
1328 					cached = 1;
1329 				else if (err->code != GOT_ERR_NO_SPACE) {
1330 					free(delta_buf);
1331 					return err;
1332 				}
1333 			}
1334 			err = got_delta_get_sizes(&base_size, &result_size,
1335 			    delta_buf, delta_len);
1336 			if (!cached)
1337 				free(delta_buf);
1338 			if (err)
1339 				return err;
1340 		} else
1341 			base_size = delta->size;
1342 		if (base_size > *max_size)
1343 			*max_size = base_size;
1344 		if (result_size > *max_size)
1345 			*max_size = result_size;
1346 	}
1347 
1348 	return NULL;
1349 }
1350 
1351 const struct got_error *
1352 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1353     struct got_pack *pack)
1354 {
1355 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1356 		return got_error(GOT_ERR_OBJ_TYPE);
1357 
1358 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1359 }
1360 
1361 const struct got_error *
1362 got_pack_dump_delta_chain_to_file(size_t *result_size,
1363     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1364     FILE *base_file, FILE *accum_file)
1365 {
1366 	const struct got_error *err = NULL;
1367 	struct got_delta *delta;
1368 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1369 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1370 	/* We process small enough files entirely in memory for speed. */
1371 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1372 	uint64_t max_size = 0;
1373 	int n = 0;
1374 
1375 	*result_size = 0;
1376 
1377 	if (STAILQ_EMPTY(&deltas->entries))
1378 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1379 
1380 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1381 		return got_error_from_errno("fseeko");
1382 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1383 		return got_error_from_errno("fseeko");
1384 
1385 	/* Deltas are ordered in ascending order. */
1386 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1387 		uint8_t *delta_buf = NULL;
1388 		uint64_t base_size, result_size = 0;
1389 		int cached = 1;
1390 		if (n == 0) {
1391 			size_t mapoff;
1392 			off_t delta_data_offset;
1393 
1394 			/* Plain object types are the delta base. */
1395 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1396 			    delta->type != GOT_OBJ_TYPE_TREE &&
1397 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1398 			    delta->type != GOT_OBJ_TYPE_TAG) {
1399 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1400 				goto done;
1401 			}
1402 
1403 			delta_data_offset = delta->offset + delta->tslen;
1404 			if (delta_data_offset >= pack->filesize) {
1405 				err = got_error(GOT_ERR_PACK_OFFSET);
1406 				goto done;
1407 			}
1408 			if (pack->map == NULL) {
1409 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1410 				    == -1) {
1411 					err = got_error_from_errno("lseek");
1412 					goto done;
1413 				}
1414 			}
1415 			if (delta->size > max_size)
1416 				max_size = delta->size;
1417 			if (max_size > max_bufsize) {
1418 				if (pack->map) {
1419 					if (delta_data_offset > SIZE_MAX) {
1420 						return got_error_fmt(
1421 						    GOT_ERR_RANGE,
1422 						    "delta offset %lld "
1423 						    "overflows size_t",
1424 						    (long long)
1425 						    delta_data_offset);
1426 					}
1427 
1428 					mapoff = delta_data_offset;
1429 					err = got_inflate_to_file_mmap(
1430 					    &base_bufsz, NULL, NULL, pack->map,
1431 					    mapoff, pack->filesize - mapoff,
1432 					    base_file);
1433 				} else
1434 					err = got_inflate_to_file_fd(
1435 					    &base_bufsz, NULL, NULL, pack->fd,
1436 					    base_file);
1437 			} else {
1438 				accum_buf = malloc(max_size);
1439 				if (accum_buf == NULL) {
1440 					err = got_error_from_errno("malloc");
1441 					goto done;
1442 				}
1443 				accum_bufsz = max_size;
1444 				if (pack->map) {
1445 					if (delta_data_offset > SIZE_MAX) {
1446 						return got_error_fmt(
1447 						    GOT_ERR_RANGE,
1448 						    "delta offset %lld "
1449 						    "overflows size_t",
1450 						    (long long)
1451 						    delta_data_offset);
1452 					}
1453 
1454 					mapoff = delta_data_offset;
1455 					err = got_inflate_to_mem_mmap(&base_buf,
1456 					    &base_bufsz, NULL, NULL,
1457 					    pack->map, mapoff,
1458 					    pack->filesize - mapoff);
1459 				} else
1460 					err = got_inflate_to_mem_fd(&base_buf,
1461 					    &base_bufsz, NULL, NULL, max_size,
1462 					    pack->fd);
1463 			}
1464 			if (err)
1465 				goto done;
1466 			n++;
1467 			if (base_buf == NULL)
1468 				rewind(base_file);
1469 			continue;
1470 		}
1471 
1472 		if (pack->delta_cache) {
1473 			got_delta_cache_get(&delta_buf, &delta_len,
1474 			    pack->delta_cache, delta->data_offset);
1475 		}
1476 		if (delta_buf == NULL) {
1477 			cached = 0;
1478 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1479 			    delta->data_offset, pack);
1480 			if (err)
1481 				goto done;
1482 		}
1483 		if (pack->delta_cache && !cached) {
1484 			err = got_delta_cache_add(pack->delta_cache,
1485 			    delta->data_offset, delta_buf, delta_len);
1486 			if (err == NULL)
1487 				cached = 1;
1488 			else if (err->code != GOT_ERR_NO_SPACE) {
1489 				free(delta_buf);
1490 				goto done;
1491 			}
1492 		}
1493 
1494 		err = got_delta_get_sizes(&base_size, &result_size,
1495 		    delta_buf, delta_len);
1496 		if (err) {
1497 			if (!cached)
1498 				free(delta_buf);
1499 			goto done;
1500 		}
1501 		if (base_size > max_size)
1502 			max_size = base_size;
1503 		if (result_size > max_size)
1504 			max_size = result_size;
1505 
1506 		if (base_buf && max_size > max_bufsize) {
1507 			/* Switch from buffers to temporary files. */
1508 			size_t w = fwrite(base_buf, 1, base_bufsz,
1509 			    base_file);
1510 			if (w != base_bufsz) {
1511 				err = got_ferror(outfile, GOT_ERR_IO);
1512 				if (!cached)
1513 					free(delta_buf);
1514 				goto done;
1515 			}
1516 			free(base_buf);
1517 			base_buf = NULL;
1518 			free(accum_buf);
1519 			accum_buf = NULL;
1520 		}
1521 
1522 		if (base_buf && max_size > base_bufsz) {
1523 			uint8_t *p = realloc(base_buf, max_size);
1524 			if (p == NULL) {
1525 				err = got_error_from_errno("realloc");
1526 				if (!cached)
1527 					free(delta_buf);
1528 				goto done;
1529 			}
1530 			base_buf = p;
1531 			base_bufsz = max_size;
1532 		}
1533 
1534 		if (accum_buf && max_size > accum_bufsz) {
1535 			uint8_t *p = realloc(accum_buf, max_size);
1536 			if (p == NULL) {
1537 				err = got_error_from_errno("realloc");
1538 				if (!cached)
1539 					free(delta_buf);
1540 				goto done;
1541 			}
1542 			accum_buf = p;
1543 			accum_bufsz = max_size;
1544 		}
1545 
1546 		if (base_buf) {
1547 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1548 			    delta_buf, delta_len, accum_buf,
1549 			    &accum_size, max_size);
1550 			n++;
1551 		} else {
1552 			err = got_delta_apply(base_file, delta_buf,
1553 			    delta_len,
1554 			    /* Final delta application writes to output file. */
1555 			    ++n < deltas->nentries ? accum_file : outfile,
1556 			    &accum_size);
1557 		}
1558 		if (!cached)
1559 			free(delta_buf);
1560 		if (err)
1561 			goto done;
1562 
1563 		if (n < deltas->nentries) {
1564 			/* Accumulated delta becomes the new base. */
1565 			if (base_buf) {
1566 				uint8_t *tmp = accum_buf;
1567 				size_t tmp_size = accum_bufsz;
1568 				accum_buf = base_buf;
1569 				accum_bufsz = base_bufsz;
1570 				base_buf = tmp;
1571 				base_bufsz = tmp_size;
1572 			} else {
1573 				FILE *tmp = accum_file;
1574 				accum_file = base_file;
1575 				base_file = tmp;
1576 				rewind(base_file);
1577 				rewind(accum_file);
1578 			}
1579 		}
1580 	}
1581 
1582 done:
1583 	free(base_buf);
1584 	if (accum_buf) {
1585 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1586 		free(accum_buf);
1587 		if (len != accum_size)
1588 			err = got_ferror(outfile, GOT_ERR_IO);
1589 	}
1590 	rewind(outfile);
1591 	if (err == NULL)
1592 		*result_size = accum_size;
1593 	return err;
1594 }
1595 
1596 const struct got_error *
1597 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1598     struct got_delta_chain *deltas, struct got_pack *pack)
1599 {
1600 	const struct got_error *err = NULL;
1601 	struct got_delta *delta;
1602 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1603 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1604 	uint64_t max_size = 0;
1605 	int n = 0;
1606 
1607 	*outbuf = NULL;
1608 	*outlen = 0;
1609 
1610 	if (STAILQ_EMPTY(&deltas->entries))
1611 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1612 
1613 	/* Deltas are ordered in ascending order. */
1614 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1615 		uint8_t *delta_buf = NULL;
1616 		uint64_t base_size, result_size = 0;
1617 		int cached = 1;
1618 		if (n == 0) {
1619 			off_t delta_data_offset;
1620 
1621 			/* Plain object types are the delta base. */
1622 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1623 			    delta->type != GOT_OBJ_TYPE_TREE &&
1624 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1625 			    delta->type != GOT_OBJ_TYPE_TAG) {
1626 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1627 				goto done;
1628 			}
1629 
1630 			delta_data_offset = delta->offset + delta->tslen;
1631 			if (delta_data_offset >= pack->filesize) {
1632 				err = got_error(GOT_ERR_PACK_OFFSET);
1633 				goto done;
1634 			}
1635 
1636 			if (delta->size > max_size)
1637 				max_size = delta->size;
1638 
1639 			if (pack->map) {
1640 				size_t mapoff;
1641 
1642 				if (delta_data_offset > SIZE_MAX) {
1643 					return got_error_fmt(GOT_ERR_RANGE,
1644 					    "delta %lld offset would "
1645 					    "overflow size_t",
1646 					    (long long)delta_data_offset);
1647 				}
1648 
1649 				mapoff = delta_data_offset;
1650 				err = got_inflate_to_mem_mmap(&base_buf,
1651 				    &base_bufsz, NULL, NULL, pack->map,
1652 				    mapoff, pack->filesize - mapoff);
1653 			} else {
1654 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1655 				    == -1) {
1656 					err = got_error_from_errno("lseek");
1657 					goto done;
1658 				}
1659 				err = got_inflate_to_mem_fd(&base_buf,
1660 				    &base_bufsz, NULL, NULL, max_size,
1661 				    pack->fd);
1662 			}
1663 			if (err)
1664 				goto done;
1665 			n++;
1666 			continue;
1667 		}
1668 
1669 		if (pack->delta_cache) {
1670 			got_delta_cache_get(&delta_buf, &delta_len,
1671 			    pack->delta_cache, delta->data_offset);
1672 		}
1673 		if (delta_buf == NULL) {
1674 			cached = 0;
1675 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1676 			    delta->data_offset, pack);
1677 			if (err)
1678 				goto done;
1679 		}
1680 		if (pack->delta_cache && !cached) {
1681 			err = got_delta_cache_add(pack->delta_cache,
1682 			    delta->data_offset, delta_buf, delta_len);
1683 			if (err == NULL)
1684 				cached = 1;
1685 			else if (err->code != GOT_ERR_NO_SPACE) {
1686 				free(delta_buf);
1687 				goto done;
1688 			}
1689 		}
1690 
1691 		err = got_delta_get_sizes(&base_size, &result_size,
1692 		    delta_buf, delta_len);
1693 		if (err) {
1694 			if (!cached)
1695 				free(delta_buf);
1696 			goto done;
1697 		}
1698 		if (base_size > max_size)
1699 			max_size = base_size;
1700 		if (result_size > max_size)
1701 			max_size = result_size;
1702 
1703 		if (max_size > base_bufsz) {
1704 			uint8_t *p = realloc(base_buf, max_size);
1705 			if (p == NULL) {
1706 				err = got_error_from_errno("realloc");
1707 				if (!cached)
1708 					free(delta_buf);
1709 				goto done;
1710 			}
1711 			base_buf = p;
1712 			base_bufsz = max_size;
1713 		}
1714 
1715 		if (max_size > accum_bufsz) {
1716 			uint8_t *p = realloc(accum_buf, max_size);
1717 			if (p == NULL) {
1718 				err = got_error_from_errno("realloc");
1719 				if (!cached)
1720 					free(delta_buf);
1721 				goto done;
1722 			}
1723 			accum_buf = p;
1724 			accum_bufsz = max_size;
1725 		}
1726 
1727 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1728 		    delta_buf, delta_len, accum_buf,
1729 		    &accum_size, max_size);
1730 		if (!cached)
1731 			free(delta_buf);
1732 		n++;
1733 		if (err)
1734 			goto done;
1735 
1736 		if (n < deltas->nentries) {
1737 			/* Accumulated delta becomes the new base. */
1738 			uint8_t *tmp = accum_buf;
1739 			size_t tmp_size = accum_bufsz;
1740 			accum_buf = base_buf;
1741 			accum_bufsz = base_bufsz;
1742 			base_buf = tmp;
1743 			base_bufsz = tmp_size;
1744 		}
1745 	}
1746 
1747 done:
1748 	free(base_buf);
1749 	if (err) {
1750 		free(accum_buf);
1751 		*outbuf = NULL;
1752 		*outlen = 0;
1753 	} else {
1754 		*outbuf = accum_buf;
1755 		*outlen = accum_size;
1756 	}
1757 	return err;
1758 }
1759 
1760 const struct got_error *
1761 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1762     FILE *outfile, FILE *base_file, FILE *accum_file)
1763 {
1764 	const struct got_error *err = NULL;
1765 
1766 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1767 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1768 
1769 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1770 		if (obj->pack_offset >= pack->filesize)
1771 			return got_error(GOT_ERR_PACK_OFFSET);
1772 
1773 		if (pack->map) {
1774 			size_t mapoff;
1775 
1776 			if (obj->pack_offset > SIZE_MAX) {
1777 				return got_error_fmt(GOT_ERR_RANGE,
1778 				    "pack offset %lld would overflow size_t",
1779 				    (long long)obj->pack_offset);
1780 			}
1781 
1782 			mapoff = obj->pack_offset;
1783 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1784 			    pack->map, mapoff, pack->filesize - mapoff,
1785 			    outfile);
1786 		} else {
1787 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1788 				return got_error_from_errno("lseek");
1789 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1790 			    pack->fd, outfile);
1791 		}
1792 	} else
1793 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1794 		    &obj->deltas, pack, outfile, base_file, accum_file);
1795 
1796 	return err;
1797 }
1798 
1799 const struct got_error *
1800 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1801     struct got_object *obj, struct got_pack *pack)
1802 {
1803 	const struct got_error *err = NULL;
1804 
1805 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1806 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1807 
1808 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1809 		if (obj->pack_offset >= pack->filesize)
1810 			return got_error(GOT_ERR_PACK_OFFSET);
1811 		if (pack->map) {
1812 			size_t mapoff;
1813 
1814 			if (obj->pack_offset > SIZE_MAX) {
1815 				return got_error_fmt(GOT_ERR_RANGE,
1816 				    "pack offset %lld would overflow size_t",
1817 				    (long long)obj->pack_offset);
1818 			}
1819 
1820 			mapoff = obj->pack_offset;
1821 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1822 			    pack->map, mapoff, pack->filesize - mapoff);
1823 		} else {
1824 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1825 				return got_error_from_errno("lseek");
1826 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1827 			    obj->size, pack->fd);
1828 		}
1829 	} else
1830 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1831 		    pack);
1832 
1833 	return err;
1834 }
1835 
1836 static const struct got_error *
1837 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1838     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1839     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1840 {
1841 	const struct got_error *err = NULL;
1842 
1843 	/* Validate decompression and obtain the decompressed size. */
1844 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1845 	    delta_data_offset, pack);
1846 	if (err)
1847 		return err;
1848 
1849 	/* Read delta base/result sizes from head of delta stream. */
1850 	err = got_delta_get_sizes(base_size, result_size,
1851 	    *delta_buf, *delta_len);
1852 	if (err)
1853 		goto done;
1854 
1855 	/* Discard decompressed delta and read it again in compressed form. */
1856 	free(*delta_buf);
1857 	*delta_buf = malloc(*delta_len_compressed);
1858 	if (*delta_buf == NULL) {
1859 		err = got_error_from_errno("malloc");
1860 		goto done;
1861 	}
1862 	if (pack->map) {
1863 		if (delta_data_offset >= pack->filesize) {
1864 			err = got_error(GOT_ERR_PACK_OFFSET);
1865 			goto done;
1866 		}
1867 		memcpy(*delta_buf, pack->map + delta_data_offset,
1868 		    *delta_len_compressed);
1869 	} else {
1870 		ssize_t n;
1871 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1872 			err = got_error_from_errno("lseek");
1873 			goto done;
1874 		}
1875 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1876 		if (n < 0) {
1877 			err = got_error_from_errno("read");
1878 			goto done;
1879 		} else if (n != *delta_len_compressed) {
1880 			err = got_error(GOT_ERR_IO);
1881 			goto done;
1882 		}
1883 	}
1884 done:
1885 	if (err) {
1886 		free(*delta_buf);
1887 		*delta_buf = NULL;
1888 		*delta_len = 0;
1889 		*delta_len_compressed = 0;
1890 		*base_size = 0;
1891 		*result_size = 0;
1892 	}
1893 	return err;
1894 }
1895 
1896 const struct got_error *
1897 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1898     size_t *delta_compressed_size, off_t *delta_offset,
1899     off_t *delta_data_offset, off_t *base_offset,
1900     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1901     struct got_pack *pack, struct got_packidx *packidx, int idx)
1902 {
1903 	const struct got_error *err = NULL;
1904 	off_t offset;
1905 	uint8_t type;
1906 	uint64_t size;
1907 	size_t tslen, delta_hdrlen;
1908 
1909 	*delta_buf = NULL;
1910 	*delta_size = 0;
1911 	*delta_compressed_size = 0;
1912 	*delta_offset = 0;
1913 	*delta_data_offset = 0;
1914 	*base_offset = 0;
1915 	*base_size = 0;
1916 	*result_size = 0;
1917 
1918 	offset = got_packidx_get_object_offset(packidx, idx);
1919 	if (offset == -1)
1920 		return got_error(GOT_ERR_BAD_PACKIDX);
1921 
1922 	if (offset >= pack->filesize)
1923 		return got_error(GOT_ERR_PACK_OFFSET);
1924 
1925 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1926 	    pack, offset);
1927 	if (err)
1928 		return err;
1929 
1930 	if (tslen + size < tslen || offset + size < size ||
1931 	    tslen + offset < tslen)
1932 		return got_error(GOT_ERR_PACK_OFFSET);
1933 
1934 	switch (type) {
1935 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1936 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1937 		    pack, offset, tslen);
1938 		if (err)
1939 			return err;
1940 		break;
1941 	case GOT_OBJ_TYPE_REF_DELTA:
1942 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1943 		if (err)
1944 			return err;
1945 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1946 		break;
1947 	default:
1948 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1949 		    "non-delta object type %d found at offset %lld",
1950 		    type, (long long)offset);
1951 	}
1952 
1953 	if (tslen + delta_hdrlen < delta_hdrlen ||
1954 	    offset + delta_hdrlen < delta_hdrlen)
1955 		return got_error(GOT_ERR_BAD_DELTA);
1956 
1957 	*delta_data_offset = offset + tslen + delta_hdrlen;
1958 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
1959 	    base_size, result_size, *delta_data_offset, pack, packidx);
1960 	if (err)
1961 		return err;
1962 
1963 	if (*delta_size != size) {
1964 		err = got_error(GOT_ERR_BAD_DELTA);
1965 		goto done;
1966 	}
1967 
1968 	*delta_offset = offset;
1969 done:
1970 	if (err) {
1971 		free(*delta_buf);
1972 		*delta_buf = NULL;
1973 		*delta_size = 0;
1974 		*delta_compressed_size = 0;
1975 		*delta_offset = 0;
1976 		*base_offset = 0;
1977 		*base_size = 0;
1978 		*result_size = 0;
1979 	}
1980 	return err;
1981 }