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