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 #include "got_compat.h"
17 
18 #include <sys/types.h>
19 #include <sys/stat.h>
20 #include <sys/queue.h>
21 #include <sys/uio.h>
22 #include <sys/mman.h>
23 #include <sys/resource.h>
24 #include <sys/socket.h>
25 
26 #include <fcntl.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include <stdint.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <limits.h>
33 #include <unistd.h>
34 #include <zlib.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_path.h"
39 
40 #include "got_lib_hash.h"
41 #include "got_lib_delta.h"
42 #include "got_lib_delta_cache.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_object_qid.h"
46 #include "got_lib_object_parse.h"
47 #include "got_lib_privsep.h"
48 #include "got_lib_pack.h"
49 
50 #ifndef nitems
51 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
52 #endif
53 
54 #ifndef MIN
55 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
56 #endif
57 
58 static const struct got_error *
59 verify_fanout_table(uint32_t *fanout_table)
60 {
61 	int i;
62 
63 	for (i = 0; i < 0xff - 1; i++) {
64 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
65 			return got_error(GOT_ERR_BAD_PACKIDX);
66 	}
67 
68 	return NULL;
69 }
70 
71 const struct got_error *
72 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
73 {
74 	const struct got_error *err = NULL;
75 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
76 	struct got_packidx_v2_hdr *h;
77 	struct got_hash ctx;
78 	uint8_t hash[GOT_HASH_DIGEST_MAXLEN];
79 	size_t nobj, len_fanout, len_ids, offset, remain;
80 	ssize_t n;
81 	int i;
82 
83 	got_hash_init(&ctx, algo);
84 
85 	h = &p->hdr;
86 	offset = 0;
87 	remain = p->len;
88 
89 	if (remain < sizeof(*h->magic)) {
90 		err = got_error(GOT_ERR_BAD_PACKIDX);
91 		goto done;
92 	}
93 	if (p->map)
94 		h->magic = (uint32_t *)(p->map + offset);
95 	else {
96 		h->magic = malloc(sizeof(*h->magic));
97 		if (h->magic == NULL) {
98 			err = got_error_from_errno("malloc");
99 			goto done;
100 		}
101 		n = read(p->fd, h->magic, sizeof(*h->magic));
102 		if (n < 0) {
103 			err = got_error_from_errno("read");
104 			goto done;
105 		} else if (n != sizeof(*h->magic)) {
106 			err = got_error(GOT_ERR_BAD_PACKIDX);
107 			goto done;
108 		}
109 	}
110 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
111 		err = got_error(GOT_ERR_BAD_PACKIDX);
112 		goto done;
113 	}
114 	offset += sizeof(*h->magic);
115 	remain -= sizeof(*h->magic);
116 
117 	if (verify)
118 		got_hash_update(&ctx, h->magic, sizeof(*h->magic));
119 
120 	if (remain < sizeof(*h->version)) {
121 		err = got_error(GOT_ERR_BAD_PACKIDX);
122 		goto done;
123 	}
124 	if (p->map)
125 		h->version = (uint32_t *)(p->map + offset);
126 	else {
127 		h->version = malloc(sizeof(*h->version));
128 		if (h->version == NULL) {
129 			err = got_error_from_errno("malloc");
130 			goto done;
131 		}
132 		n = read(p->fd, h->version, sizeof(*h->version));
133 		if (n < 0) {
134 			err = got_error_from_errno("read");
135 			goto done;
136 		} else if (n != sizeof(*h->version)) {
137 			err = got_error(GOT_ERR_BAD_PACKIDX);
138 			goto done;
139 		}
140 	}
141 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
142 		err = got_error(GOT_ERR_BAD_PACKIDX);
143 		goto done;
144 	}
145 	offset += sizeof(*h->version);
146 	remain -= sizeof(*h->version);
147 
148 	if (verify)
149 		got_hash_update(&ctx, h->version, sizeof(*h->version));
150 
151 	len_fanout =
152 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
153 	if (remain < len_fanout) {
154 		err = got_error(GOT_ERR_BAD_PACKIDX);
155 		goto done;
156 	}
157 	if (p->map)
158 		h->fanout_table = (uint32_t *)(p->map + offset);
159 	else {
160 		h->fanout_table = malloc(len_fanout);
161 		if (h->fanout_table == NULL) {
162 			err = got_error_from_errno("malloc");
163 			goto done;
164 		}
165 		n = read(p->fd, h->fanout_table, len_fanout);
166 		if (n < 0) {
167 			err = got_error_from_errno("read");
168 			goto done;
169 		} else if (n != len_fanout) {
170 			err = got_error(GOT_ERR_BAD_PACKIDX);
171 			goto done;
172 		}
173 	}
174 	err = verify_fanout_table(h->fanout_table);
175 	if (err)
176 		goto done;
177 	if (verify)
178 		got_hash_update(&ctx, h->fanout_table, len_fanout);
179 	offset += len_fanout;
180 	remain -= len_fanout;
181 
182 	nobj = be32toh(h->fanout_table[0xff]);
183 	len_ids = nobj * sizeof(*h->sorted_ids);
184 	if (len_ids <= nobj || len_ids > remain) {
185 		err = got_error(GOT_ERR_BAD_PACKIDX);
186 		goto done;
187 	}
188 	if (p->map)
189 		h->sorted_ids =
190 		    (struct got_packidx_object_id *)((uint8_t*)(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 < sizeof(*h->trailer)) {
305 		err = got_error(GOT_ERR_BAD_PACKIDX);
306 		goto done;
307 	}
308 	if (p->map)
309 		h->trailer =
310 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
311 	else {
312 		h->trailer = malloc(sizeof(*h->trailer));
313 		if (h->trailer == NULL) {
314 			err = got_error_from_errno("malloc");
315 			goto done;
316 		}
317 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
318 		if (n < 0)
319 			err = got_error_from_errno("read");
320 		else if (n != sizeof(*h->trailer)) {
321 			err = got_error(GOT_ERR_BAD_PACKIDX);
322 			goto done;
323 		}
324 	}
325 	if (verify) {
326 		got_hash_update(&ctx, h->trailer->packfile_sha1,
327 		    SHA1_DIGEST_LENGTH);
328 		got_hash_final(&ctx, hash);
329 		if (got_hash_cmp(ctx.algo, hash, h->trailer->packidx_sha1) != 0)
330 			err = got_error(GOT_ERR_PACKIDX_CSUM);
331 	}
332 done:
333 	return err;
334 }
335 
336 const struct got_error *
337 got_packidx_open(struct got_packidx **packidx,
338     int dir_fd, const char *relpath, int verify)
339 {
340 	const struct got_error *err = NULL;
341 	struct got_packidx *p = NULL;
342 	char *pack_relpath;
343 	struct stat idx_sb, pack_sb;
344 
345 	*packidx = NULL;
346 
347 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
348 	if (err)
349 		return err;
350 
351 	/*
352 	 * Ensure that a corresponding pack file exists.
353 	 * Some Git repositories have this problem. Git seems to ignore
354 	 * the existence of lonely pack index files but we do not.
355 	 */
356 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
357 		if (errno == ENOENT) {
358 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
359 			    "%s", relpath);
360 		} else
361 			err = got_error_from_errno2("fstatat", pack_relpath);
362 		goto done;
363 	}
364 
365 	p = calloc(1, sizeof(*p));
366 	if (p == NULL) {
367 		err = got_error_from_errno("calloc");
368 		goto done;
369 	}
370 
371 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
372 	if (p->fd == -1) {
373 		err = got_error_from_errno2("openat", relpath);
374 		goto done;
375 	}
376 
377 	if (fstat(p->fd, &idx_sb) != 0) {
378 		err = got_error_from_errno2("fstat", relpath);
379 		goto done;
380 	}
381 	p->len = idx_sb.st_size;
382 	if (p->len < sizeof(p->hdr)) {
383 		err = got_error(GOT_ERR_BAD_PACKIDX);
384 		goto done;
385 	}
386 
387 	p->path_packidx = strdup(relpath);
388 	if (p->path_packidx == NULL) {
389 		err = got_error_from_errno("strdup");
390 		goto done;
391 	}
392 
393 #ifndef GOT_PACK_NO_MMAP
394 	if (p->len > 0 && p->len <= SIZE_MAX) {
395 		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
396 		if (p->map == MAP_FAILED) {
397 			if (errno != ENOMEM) {
398 				err = got_error_from_errno("mmap");
399 				goto done;
400 			}
401 			p->map = NULL; /* fall back to read(2) */
402 		}
403 	}
404 #endif
405 
406 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
407 done:
408 	if (err) {
409 		if (p)
410 			got_packidx_close(p);
411 	} else
412 		*packidx = p;
413 	free(pack_relpath);
414 	return err;
415 }
416 
417 const struct got_error *
418 got_packidx_close(struct got_packidx *packidx)
419 {
420 	const struct got_error *err = NULL;
421 
422 	free(packidx->path_packidx);
423 	if (packidx->map) {
424 		if (munmap(packidx->map, packidx->len) == -1)
425 			err = got_error_from_errno("munmap");
426 	} else {
427 		free(packidx->hdr.magic);
428 		free(packidx->hdr.version);
429 		free(packidx->hdr.fanout_table);
430 		free(packidx->hdr.sorted_ids);
431 		free(packidx->hdr.crc32);
432 		free(packidx->hdr.offsets);
433 		free(packidx->hdr.large_offsets);
434 		free(packidx->hdr.trailer);
435 	}
436 	if (close(packidx->fd) == -1 && err == NULL)
437 		err = got_error_from_errno("close");
438 	free(packidx->sorted_offsets);
439 	free(packidx->sorted_large_offsets);
440 	free(packidx);
441 
442 	return err;
443 }
444 
445 const struct got_error *
446 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
447 {
448 	size_t size;
449 
450 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
451 	size = strlen(path_packidx) + 2;
452 	if (size < GOT_PACKFILE_NAMELEN + 1)
453 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
454 
455 	*path_packfile = malloc(size);
456 	if (*path_packfile == NULL)
457 		return got_error_from_errno("malloc");
458 
459 	/* Copy up to and excluding ".idx". */
460 	if (strlcpy(*path_packfile, path_packidx,
461 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
462 		return got_error(GOT_ERR_NO_SPACE);
463 
464 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
465 		return got_error(GOT_ERR_NO_SPACE);
466 
467 	return NULL;
468 }
469 
470 off_t
471 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
472 {
473 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
474 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
475 		uint64_t loffset;
476 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
477 		if (idx < 0 || idx >= packidx->nlargeobj ||
478 		    packidx->hdr.large_offsets == NULL)
479 			return -1;
480 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
481 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
482 	}
483 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
484 }
485 
486 int
487 got_packidx_get_object_idx(struct got_packidx *packidx,
488     struct got_object_id *id)
489 {
490 	u_int8_t id0 = id->sha1[0];
491 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
492 	int left = 0, right = totobj - 1;
493 
494 	if (id0 > 0)
495 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
496 
497 	while (left <= right) {
498 		struct got_packidx_object_id *oid;
499 		int i, cmp;
500 
501 		i = ((left + right) / 2);
502 		oid = &packidx->hdr.sorted_ids[i];
503 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
504 		if (cmp == 0)
505 			return i;
506 		else if (cmp > 0)
507 			left = i + 1;
508 		else if (cmp < 0)
509 			right = i - 1;
510 	}
511 
512 	return -1;
513 }
514 
515 static int
516 offset_cmp(const void *pa, const void *pb)
517 {
518 	const struct got_pack_offset_index *a, *b;
519 
520 	a = (const struct got_pack_offset_index *)pa;
521 	b = (const struct got_pack_offset_index *)pb;
522 
523 	if (a->offset < b->offset)
524 		return -1;
525 	else if (a->offset > b->offset)
526 		return 1;
527 
528 	return 0;
529 }
530 
531 static int
532 large_offset_cmp(const void *pa, const void *pb)
533 {
534 	const struct got_pack_large_offset_index *a, *b;
535 
536 	a = (const struct got_pack_large_offset_index *)pa;
537 	b = (const struct got_pack_large_offset_index *)pb;
538 
539 	if (a->offset < b->offset)
540 		return -1;
541 	else if (a->offset > b->offset)
542 		return 1;
543 
544 	return 0;
545 }
546 
547 static const struct got_error *
548 build_offset_index(struct got_packidx *p)
549 {
550 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
551 	unsigned int i, j, k;
552 
553 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
554 	    sizeof(p->sorted_offsets[0]));
555 	if (p->sorted_offsets == NULL)
556 		return got_error_from_errno("calloc");
557 
558 	if (p->nlargeobj > 0) {
559 		p->sorted_large_offsets = calloc(p->nlargeobj,
560 		    sizeof(p->sorted_large_offsets[0]));
561 		if (p->sorted_large_offsets == NULL)
562 			return got_error_from_errno("calloc");
563 	}
564 
565 	j = 0;
566 	k = 0;
567 	for (i = 0; i < nobj; i++) {
568 		uint32_t offset = be32toh(p->hdr.offsets[i]);
569 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
570 			uint64_t loffset;
571 			uint32_t idx;
572 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
573 			if (idx >= p->nlargeobj ||
574 			    p->nlargeobj == 0 ||
575 			    p->hdr.large_offsets == NULL)
576 				return got_error(GOT_ERR_BAD_PACKIDX);
577 			loffset = be64toh(p->hdr.large_offsets[idx]);
578 			p->sorted_large_offsets[j].offset = loffset;
579 			p->sorted_large_offsets[j].idx = i;
580 			j++;
581 		} else {
582 			p->sorted_offsets[k].offset = offset;
583 			p->sorted_offsets[k].idx = i;
584 			k++;
585 		}
586 	}
587 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
588 		return got_error(GOT_ERR_BAD_PACKIDX);
589 
590 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
591 	    sizeof(p->sorted_offsets[0]), offset_cmp);
592 
593 	if (p->sorted_large_offsets)
594 		qsort(p->sorted_large_offsets, p->nlargeobj,
595 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
596 
597 	return NULL;
598 }
599 
600 const struct got_error *
601 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
602 {
603 	const struct got_error *err;
604 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
605 	int i, left, right;
606 
607 	*idx = -1;
608 
609 	if (packidx->sorted_offsets == NULL) {
610 		err = build_offset_index(packidx);
611 		if (err)
612 			return err;
613 	}
614 
615 	if (offset >= 0x7fffffff) {
616 		uint64_t lo;
617 		left = 0, right = packidx->nlargeobj - 1;
618 		while (left <= right) {
619 			i = ((left + right) / 2);
620 			lo = packidx->sorted_large_offsets[i].offset;
621 			if (lo == offset) {
622 				*idx = packidx->sorted_large_offsets[i].idx;
623 				break;
624 			} else if (offset > lo)
625 				left = i + 1;
626 			else if (offset < lo)
627 				right = i - 1;
628 		}
629 	} else {
630 		uint32_t o;
631 		left = 0, right = totobj - packidx->nlargeobj - 1;
632 		while (left <= right) {
633 			i = ((left + right) / 2);
634 			o = packidx->sorted_offsets[i].offset;
635 			if (o == offset) {
636 				*idx = packidx->sorted_offsets[i].idx;
637 				break;
638 			} else if (offset > o)
639 				left = i + 1;
640 			else if (offset < o)
641 				right = i - 1;
642 		}
643 	}
644 
645 	return NULL;
646 }
647 
648 const struct got_error *
649 got_packidx_get_object_id(struct got_object_id *id,
650     struct got_packidx *packidx, int idx)
651 {
652 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
653 	struct got_packidx_object_id *oid;
654 
655 	if (idx < 0 || idx >= totobj)
656 		return got_error(GOT_ERR_NO_OBJ);
657 
658 	oid = &packidx->hdr.sorted_ids[idx];
659 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
660 	return NULL;
661 }
662 
663 const struct got_error *
664 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
665     struct got_packidx *packidx, const char *id_str_prefix)
666 {
667 	const struct got_error *err = NULL;
668 	u_int8_t id0;
669 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
670 	char hex[3];
671 	size_t prefix_len = strlen(id_str_prefix);
672 	struct got_packidx_object_id *oid;
673 	uint32_t i = 0;
674 
675 	STAILQ_INIT(matched_ids);
676 
677 	if (prefix_len < 2)
678 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
679 
680 	hex[0] = id_str_prefix[0];
681 	hex[1] = id_str_prefix[1];
682 	hex[2] = '\0';
683 	if (!got_parse_xdigit(&id0, hex))
684 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
685 
686 	if (id0 > 0)
687 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
688 	oid = &packidx->hdr.sorted_ids[i];
689 	while (i < totobj && oid->sha1[0] == id0) {
690 		char id_str[SHA1_DIGEST_STRING_LENGTH];
691 		struct got_object_qid *qid;
692 		int cmp;
693 
694 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
695 		        return got_error(GOT_ERR_NO_SPACE);
696 
697 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
698 		if (cmp < 0) {
699 			oid = &packidx->hdr.sorted_ids[++i];
700 			continue;
701 		} else if (cmp > 0)
702 			break;
703 
704 		err = got_object_qid_alloc_partial(&qid);
705 		if (err)
706 			break;
707 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
708 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
709 
710 		oid = &packidx->hdr.sorted_ids[++i];
711 	}
712 
713 	if (err)
714 		got_object_id_queue_free(matched_ids);
715 	return err;
716 }
717 
718 static void
719 set_max_datasize(void)
720 {
721 	struct rlimit rl;
722 
723 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
724 		return;
725 
726 	rl.rlim_cur = rl.rlim_max;
727 	setrlimit(RLIMIT_DATA, &rl);
728 }
729 
730 const struct got_error *
731 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
732 {
733 	const struct got_error *err = NULL;
734 	int imsg_fds[2];
735 	pid_t pid;
736 	struct imsgbuf *ibuf;
737 
738 	ibuf = calloc(1, sizeof(*ibuf));
739 	if (ibuf == NULL)
740 		return got_error_from_errno("calloc");
741 
742 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
743 	if (pack->privsep_child == NULL) {
744 		err = got_error_from_errno("calloc");
745 		free(ibuf);
746 		return err;
747 	}
748 	pack->child_has_tempfiles = 0;
749 	pack->child_has_delta_outfd = 0;
750 
751 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
752 		err = got_error_from_errno("socketpair");
753 		goto done;
754 	}
755 
756 	pid = fork();
757 	if (pid == -1) {
758 		err = got_error_from_errno("fork");
759 		goto done;
760 	} else if (pid == 0) {
761 		set_max_datasize();
762 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
763 		    pack->path_packfile);
764 		/* not reached */
765 	}
766 
767 	if (close(imsg_fds[1]) == -1)
768 		return got_error_from_errno("close");
769 	pack->privsep_child->imsg_fd = imsg_fds[0];
770 	pack->privsep_child->pid = pid;
771 	imsg_init(ibuf, imsg_fds[0]);
772 	pack->privsep_child->ibuf = ibuf;
773 
774 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
775 	if (err) {
776 		const struct got_error *child_err;
777 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
778 		child_err = got_privsep_wait_for_child(
779 		    pack->privsep_child->pid);
780 		if (child_err && err == NULL)
781 			err = child_err;
782 	}
783 done:
784 	if (err) {
785 		free(ibuf);
786 		free(pack->privsep_child);
787 		pack->privsep_child = NULL;
788 	}
789 	return err;
790 }
791 
792 static const struct got_error *
793 pack_stop_privsep_child(struct got_pack *pack)
794 {
795 	const struct got_error *err = NULL, *close_err = NULL;
796 
797 	if (pack->privsep_child == NULL)
798 		return NULL;
799 
800 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
801 	if (err)
802 		return err;
803 	if (close(pack->privsep_child->imsg_fd) == -1)
804 		close_err = got_error_from_errno("close");
805 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
806 	if (close_err && err == NULL)
807 		err = close_err;
808 	imsg_clear(pack->privsep_child->ibuf);
809 	free(pack->privsep_child->ibuf);
810 	free(pack->privsep_child);
811 	pack->privsep_child = NULL;
812 	return err;
813 }
814 
815 const struct got_error *
816 got_pack_close(struct got_pack *pack)
817 {
818 	const struct got_error *err = NULL;
819 
820 	err = pack_stop_privsep_child(pack);
821 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
822 		err = got_error_from_errno("munmap");
823 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
824 		err = got_error_from_errno("close");
825 	pack->fd = -1;
826 	free(pack->path_packfile);
827 	pack->path_packfile = NULL;
828 	pack->filesize = 0;
829 	if (pack->delta_cache) {
830 		got_delta_cache_free(pack->delta_cache);
831 		pack->delta_cache = NULL;
832 	}
833 
834 	/*
835 	 * Leave accumfd and basefd alone. They are managed by the
836 	 * repository layer and can be reused.
837 	 */
838 
839 	return err;
840 }
841 
842 const struct got_error *
843 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
844     struct got_pack *pack, off_t offset)
845 {
846 	uint8_t t = 0;
847 	uint64_t s = 0;
848 	uint8_t sizeN;
849 	size_t mapoff = 0;
850 	int i = 0;
851 
852 	*len = 0;
853 
854 	if (offset >= pack->filesize)
855 		return got_error(GOT_ERR_PACK_OFFSET);
856 
857 	if (pack->map) {
858 		if (offset > SIZE_MAX) {
859 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
860 			    "offset %lld overflows size_t",
861 			    (long long)offset);
862 		}
863 
864 		mapoff = (size_t)offset;
865 	} else {
866 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
867 			return got_error_from_errno("lseek");
868 	}
869 
870 	do {
871 		/* We do not support size values which don't fit in 64 bit. */
872 		if (i > 9)
873 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
874 			    "packfile offset %lld", (long long)offset);
875 
876 		if (pack->map) {
877 			if (mapoff + sizeof(sizeN) >= pack->filesize)
878 				return got_error(GOT_ERR_BAD_PACKFILE);
879 			sizeN = *(pack->map + mapoff);
880 			mapoff += sizeof(sizeN);
881 		} else {
882 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
883 			if (n < 0)
884 				return got_error_from_errno("read");
885 			if (n != sizeof(sizeN))
886 				return got_error(GOT_ERR_BAD_PACKFILE);
887 		}
888 		*len += sizeof(sizeN);
889 
890 		if (i == 0) {
891 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
892 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
893 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
894 		} else {
895 			size_t shift = 4 + 7 * (i - 1);
896 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
897 		}
898 		i++;
899 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
900 
901 	*type = t;
902 	*size = s;
903 	return NULL;
904 }
905 
906 static const struct got_error *
907 open_plain_object(struct got_object **obj, struct got_object_id *id,
908     uint8_t type, off_t offset, size_t size, int idx)
909 {
910 	*obj = calloc(1, sizeof(**obj));
911 	if (*obj == NULL)
912 		return got_error_from_errno("calloc");
913 
914 	(*obj)->type = type;
915 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
916 	(*obj)->pack_idx = idx;
917 	(*obj)->hdrlen = 0;
918 	(*obj)->size = size;
919 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
920 	(*obj)->pack_offset = offset;
921 
922 	return NULL;
923 }
924 
925 static const struct got_error *
926 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
927     off_t delta_offset)
928 {
929 	int64_t o = 0;
930 	uint8_t offN;
931 	int i = 0;
932 
933 	*offset = 0;
934 	*len = 0;
935 
936 	do {
937 		/* We do not support offset values which don't fit in 64 bit. */
938 		if (i > 8)
939 			return got_error(GOT_ERR_NO_SPACE);
940 
941 		if (pack->map) {
942 			size_t mapoff;
943 
944 			if (delta_offset + *len > SIZE_MAX) {
945 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
946 				    "mapoff %lld would overflow size_t",
947 				    (long long)delta_offset + *len);
948 			}
949 
950 			mapoff = (size_t)delta_offset + *len;
951 			if (mapoff + sizeof(offN) >= pack->filesize)
952 				return got_error(GOT_ERR_PACK_OFFSET);
953 			offN = *(pack->map + mapoff);
954 		} else {
955 			ssize_t n;
956 			n = read(pack->fd, &offN, sizeof(offN));
957 			if (n < 0)
958 				return got_error_from_errno("read");
959 			if (n != sizeof(offN))
960 				return got_error(GOT_ERR_BAD_PACKFILE);
961 		}
962 		*len += sizeof(offN);
963 
964 		if (i == 0)
965 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
966 		else {
967 			o++;
968 			o <<= 7;
969 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
970 		}
971 		i++;
972 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
973 
974 	*offset = o;
975 	return NULL;
976 }
977 
978 const struct got_error *
979 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
980     struct got_pack *pack, off_t offset, size_t tslen)
981 {
982 	const struct got_error *err;
983 	int64_t negoffset;
984 	size_t negofflen;
985 
986 	*len = 0;
987 
988 	err = parse_negative_offset(&negoffset, &negofflen, pack,
989 	    offset + tslen);
990 	if (err)
991 		return err;
992 
993 	/* Compute the base object's offset (must be in the same pack file). */
994 	*base_offset = (offset - negoffset);
995 	if (*base_offset <= 0)
996 		return got_error(GOT_ERR_BAD_PACKFILE);
997 
998 	*len = negofflen;
999 	return NULL;
1000 }
1001 
1002 static const struct got_error *
1003 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1004     size_t *delta_compressed_len, size_t delta_data_offset,
1005     struct got_pack *pack)
1006 {
1007 	const struct got_error *err = NULL;
1008 	size_t consumed = 0;
1009 
1010 	if (pack->map) {
1011 		if (delta_data_offset >= pack->filesize)
1012 			return got_error(GOT_ERR_PACK_OFFSET);
1013 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1014 		    &consumed, NULL, pack->map, delta_data_offset,
1015 		    pack->filesize - delta_data_offset);
1016 		if (err)
1017 			return err;
1018 	} else {
1019 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1020 			return got_error_from_errno("lseek");
1021 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1022 		    &consumed, NULL, 0, pack->fd);
1023 		if (err)
1024 			return err;
1025 	}
1026 
1027 	if (delta_compressed_len)
1028 		*delta_compressed_len = consumed;
1029 
1030 	return NULL;
1031 }
1032 
1033 static const struct got_error *
1034 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1035     int delta_type, size_t delta_size, off_t delta_data_offset)
1036 {
1037 	struct got_delta *delta;
1038 
1039 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1040 	    delta_data_offset);
1041 	if (delta == NULL)
1042 		return got_error_from_errno("got_delta_open");
1043 	/* delta is freed in got_object_close() */
1044 	deltas->nentries++;
1045 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1046 	return NULL;
1047 }
1048 
1049 static const struct got_error *
1050 resolve_offset_delta(struct got_delta_chain *deltas,
1051     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1052     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1053 {
1054 	const struct got_error *err;
1055 	off_t base_offset;
1056 	uint8_t base_type;
1057 	uint64_t base_size;
1058 	size_t base_tslen;
1059 	off_t delta_data_offset;
1060 	size_t consumed;
1061 
1062 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1063 	    delta_offset, tslen);
1064 	if (err)
1065 		return err;
1066 
1067 	delta_data_offset = delta_offset + tslen + consumed;
1068 	if (delta_data_offset >= pack->filesize)
1069 		return got_error(GOT_ERR_PACK_OFFSET);
1070 
1071 	if (pack->map == NULL) {
1072 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1073 		if (delta_data_offset == -1)
1074 			return got_error_from_errno("lseek");
1075 	}
1076 
1077 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1078 	    delta_data_offset);
1079 	if (err)
1080 		return err;
1081 
1082 	/* An offset delta must be in the same packfile. */
1083 	if (base_offset >= pack->filesize)
1084 		return got_error(GOT_ERR_PACK_OFFSET);
1085 
1086 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1087 	    &base_tslen, pack, base_offset);
1088 	if (err)
1089 		return err;
1090 
1091 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1092 	    base_tslen, base_type, base_size, recursion - 1);
1093 }
1094 
1095 const struct got_error *
1096 got_pack_parse_ref_delta(struct got_object_id *id,
1097     struct got_pack *pack, off_t delta_offset, int tslen)
1098 {
1099 	if (pack->map) {
1100 		size_t mapoff;
1101 
1102 		if (delta_offset + tslen > SIZE_MAX) {
1103 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1104 			    "mapoff %lld would overflow size_t",
1105 			    (long long)delta_offset + tslen);
1106 		}
1107 
1108 		mapoff = delta_offset + tslen;
1109 		if (mapoff + sizeof(*id) >= pack->filesize)
1110 			return got_error(GOT_ERR_PACK_OFFSET);
1111 		memcpy(id, pack->map + mapoff, sizeof(*id));
1112 	} else {
1113 		ssize_t n;
1114 		n = read(pack->fd, id, sizeof(*id));
1115 		if (n < 0)
1116 			return got_error_from_errno("read");
1117 		if (n != sizeof(*id))
1118 			return got_error(GOT_ERR_BAD_PACKFILE);
1119 	}
1120 
1121 	return NULL;
1122 }
1123 
1124 static const struct got_error *
1125 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1126     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1127     size_t delta_size, unsigned int recursion)
1128 {
1129 	const struct got_error *err;
1130 	struct got_object_id id;
1131 	int idx;
1132 	off_t base_offset;
1133 	uint8_t base_type;
1134 	uint64_t base_size;
1135 	size_t base_tslen;
1136 	off_t delta_data_offset;
1137 
1138 	if (delta_offset + tslen >= pack->filesize)
1139 		return got_error(GOT_ERR_PACK_OFFSET);
1140 
1141 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1142 	if (err)
1143 		return err;
1144 	if (pack->map) {
1145 		delta_data_offset = delta_offset + tslen + SHA1_DIGEST_LENGTH;
1146 	} else {
1147 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1148 		if (delta_data_offset == -1)
1149 			return got_error_from_errno("lseek");
1150 	}
1151 
1152 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1153 	    delta_data_offset);
1154 	if (err)
1155 		return err;
1156 
1157 	/* Delta base must be in the same pack file. */
1158 	idx = got_packidx_get_object_idx(packidx, &id);
1159 	if (idx == -1)
1160 		return got_error(GOT_ERR_NO_OBJ);
1161 
1162 	base_offset = got_packidx_get_object_offset(packidx, idx);
1163 	if (base_offset == -1)
1164 		return got_error(GOT_ERR_BAD_PACKIDX);
1165 
1166 	if (base_offset >= pack->filesize)
1167 		return got_error(GOT_ERR_PACK_OFFSET);
1168 
1169 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1170 	    &base_tslen, pack, base_offset);
1171 	if (err)
1172 		return err;
1173 
1174 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1175 	    base_tslen, base_type, base_size, recursion - 1);
1176 }
1177 
1178 const struct got_error *
1179 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1180     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1181     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1182 {
1183 	const struct got_error *err = NULL;
1184 
1185 	if (--recursion == 0)
1186 		return got_error(GOT_ERR_RECURSION);
1187 
1188 	switch (delta_type) {
1189 	case GOT_OBJ_TYPE_COMMIT:
1190 	case GOT_OBJ_TYPE_TREE:
1191 	case GOT_OBJ_TYPE_BLOB:
1192 	case GOT_OBJ_TYPE_TAG:
1193 		/* Plain types are the final delta base. Recursion ends. */
1194 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1195 		    delta_size, 0);
1196 		break;
1197 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1198 		err = resolve_offset_delta(deltas, packidx, pack,
1199 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1200 		break;
1201 	case GOT_OBJ_TYPE_REF_DELTA:
1202 		err = resolve_ref_delta(deltas, packidx, pack,
1203 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1204 		break;
1205 	default:
1206 		return got_error(GOT_ERR_OBJ_TYPE);
1207 	}
1208 
1209 	return err;
1210 }
1211 
1212 static const struct got_error *
1213 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1214     struct got_pack *pack, struct got_object_id *id, off_t offset,
1215     size_t tslen, int delta_type, size_t delta_size, int idx)
1216 {
1217 	const struct got_error *err = NULL;
1218 	int resolved_type;
1219 
1220 	*obj = calloc(1, sizeof(**obj));
1221 	if (*obj == NULL)
1222 		return got_error_from_errno("calloc");
1223 
1224 	(*obj)->flags = 0;
1225 	(*obj)->hdrlen = 0;
1226 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1227 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1228 	(*obj)->pack_offset = offset + tslen;
1229 
1230 	STAILQ_INIT(&(*obj)->deltas.entries);
1231 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1232 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1233 	(*obj)->pack_idx = idx;
1234 
1235 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1236 	    offset, tslen, delta_type, delta_size,
1237 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1238 	if (err)
1239 		goto done;
1240 
1241 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1242 	if (err)
1243 		goto done;
1244 	(*obj)->type = resolved_type;
1245 done:
1246 	if (err) {
1247 		got_object_close(*obj);
1248 		*obj = NULL;
1249 	}
1250 	return err;
1251 }
1252 
1253 const struct got_error *
1254 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1255     struct got_packidx *packidx, int idx, struct got_object_id *id)
1256 {
1257 	const struct got_error *err = NULL;
1258 	off_t offset;
1259 	uint8_t type;
1260 	uint64_t size;
1261 	size_t tslen;
1262 
1263 	*obj = NULL;
1264 
1265 	offset = got_packidx_get_object_offset(packidx, idx);
1266 	if (offset == -1)
1267 		return got_error(GOT_ERR_BAD_PACKIDX);
1268 
1269 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1270 	    pack, offset);
1271 	if (err)
1272 		return err;
1273 
1274 	switch (type) {
1275 	case GOT_OBJ_TYPE_COMMIT:
1276 	case GOT_OBJ_TYPE_TREE:
1277 	case GOT_OBJ_TYPE_BLOB:
1278 	case GOT_OBJ_TYPE_TAG:
1279 		err = open_plain_object(obj, id, type, offset + tslen,
1280 		    size, idx);
1281 		break;
1282 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1283 	case GOT_OBJ_TYPE_REF_DELTA:
1284 		err = open_delta_object(obj, packidx, pack, id, offset,
1285 		    tslen, type, size, idx);
1286 		break;
1287 	default:
1288 		err = got_error(GOT_ERR_OBJ_TYPE);
1289 		break;
1290 	}
1291 
1292 	return err;
1293 }
1294 
1295 const struct got_error *
1296 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1297     struct got_delta_chain *deltas, struct got_pack *pack)
1298 {
1299 	struct got_delta *delta;
1300 	uint64_t base_size = 0, result_size = 0;
1301 
1302 	*max_size = 0;
1303 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1304 		/* Plain object types are the delta base. */
1305 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1306 		    delta->type != GOT_OBJ_TYPE_TREE &&
1307 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1308 		    delta->type != GOT_OBJ_TYPE_TAG) {
1309 			const struct got_error *err;
1310 			uint8_t *delta_buf = NULL;
1311 			size_t delta_len;
1312 			int cached = 1;
1313 
1314 			if (pack->delta_cache) {
1315 				got_delta_cache_get(&delta_buf, &delta_len,
1316 				    NULL, NULL, pack->delta_cache,
1317 				    delta->data_offset);
1318 			}
1319 			if (delta_buf == NULL) {
1320 				cached = 0;
1321 				err = read_delta_data(&delta_buf, &delta_len,
1322 				    NULL, delta->data_offset, pack);
1323 				if (err)
1324 					return err;
1325 			}
1326 			if (pack->delta_cache && !cached) {
1327 				err = got_delta_cache_add(pack->delta_cache,
1328 				    delta->data_offset, delta_buf, delta_len);
1329 				if (err == NULL)
1330 					cached = 1;
1331 				else if (err->code != GOT_ERR_NO_SPACE) {
1332 					free(delta_buf);
1333 					return err;
1334 				}
1335 			}
1336 			err = got_delta_get_sizes(&base_size, &result_size,
1337 			    delta_buf, delta_len);
1338 			if (!cached)
1339 				free(delta_buf);
1340 			if (err)
1341 				return err;
1342 		} else
1343 			base_size = delta->size;
1344 		if (base_size > *max_size)
1345 			*max_size = base_size;
1346 		if (result_size > *max_size)
1347 			*max_size = result_size;
1348 	}
1349 
1350 	return NULL;
1351 }
1352 
1353 const struct got_error *
1354 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1355     struct got_pack *pack)
1356 {
1357 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1358 		return got_error(GOT_ERR_OBJ_TYPE);
1359 
1360 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1361 }
1362 
1363 const struct got_error *
1364 got_pack_dump_delta_chain_to_file(size_t *result_size,
1365     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1366     FILE *base_file, FILE *accum_file)
1367 {
1368 	const struct got_error *err = NULL;
1369 	struct got_delta *delta;
1370 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1371 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1372 	/* We process small enough files entirely in memory for speed. */
1373 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1374 	uint64_t max_size = 0;
1375 	int n = 0;
1376 
1377 	*result_size = 0;
1378 
1379 	if (STAILQ_EMPTY(&deltas->entries))
1380 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1381 
1382 	if (pack->delta_cache) {
1383 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1384 		size_t delta_len, fulltext_len;
1385 
1386 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1387 		got_delta_cache_get(&delta_buf, &delta_len,
1388 		    &fulltext, &fulltext_len,
1389 		    pack->delta_cache, delta->data_offset);
1390 		if (fulltext) {
1391 			size_t w;
1392 
1393 			w = fwrite(fulltext, 1, fulltext_len, outfile);
1394 			if (w != fulltext_len)
1395 				return got_ferror(outfile, GOT_ERR_IO);
1396 			if (fflush(outfile) != 0)
1397 				return got_error_from_errno("fflush");
1398 			*result_size = fulltext_len;
1399 			return NULL;
1400 		}
1401 	}
1402 
1403 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1404 		return got_error_from_errno("fseeko");
1405 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1406 		return got_error_from_errno("fseeko");
1407 
1408 	/* Deltas are ordered in ascending order. */
1409 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1410 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1411 		size_t delta_len, fulltext_len;
1412 		uint64_t base_size, result_size = 0;
1413 		int cached = 1;
1414 		if (n == 0) {
1415 			size_t mapoff;
1416 			off_t delta_data_offset;
1417 
1418 			/* Plain object types are the delta base. */
1419 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1420 			    delta->type != GOT_OBJ_TYPE_TREE &&
1421 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1422 			    delta->type != GOT_OBJ_TYPE_TAG) {
1423 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1424 				goto done;
1425 			}
1426 
1427 			delta_data_offset = delta->offset + delta->tslen;
1428 			if (delta_data_offset >= pack->filesize) {
1429 				err = got_error(GOT_ERR_PACK_OFFSET);
1430 				goto done;
1431 			}
1432 			if (pack->map == NULL) {
1433 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1434 				    == -1) {
1435 					err = got_error_from_errno("lseek");
1436 					goto done;
1437 				}
1438 			}
1439 			if (delta->size > max_size)
1440 				max_size = delta->size;
1441 			if (max_size > max_bufsize) {
1442 				if (pack->map) {
1443 					if (delta_data_offset > SIZE_MAX) {
1444 						return got_error_fmt(
1445 						    GOT_ERR_RANGE,
1446 						    "delta offset %lld "
1447 						    "overflows size_t",
1448 						    (long long)
1449 						    delta_data_offset);
1450 					}
1451 
1452 					mapoff = delta_data_offset;
1453 					err = got_inflate_to_file_mmap(
1454 					    &base_bufsz, NULL, NULL, pack->map,
1455 					    mapoff, pack->filesize - mapoff,
1456 					    base_file);
1457 				} else
1458 					err = got_inflate_to_file_fd(
1459 					    &base_bufsz, NULL, NULL, pack->fd,
1460 					    base_file);
1461 			} else {
1462 				accum_buf = malloc(max_size);
1463 				if (accum_buf == NULL) {
1464 					err = got_error_from_errno("malloc");
1465 					goto done;
1466 				}
1467 				accum_bufsz = max_size;
1468 				if (pack->map) {
1469 					if (delta_data_offset > SIZE_MAX) {
1470 						return got_error_fmt(
1471 						    GOT_ERR_RANGE,
1472 						    "delta offset %lld "
1473 						    "overflows size_t",
1474 						    (long long)
1475 						    delta_data_offset);
1476 					}
1477 
1478 					mapoff = delta_data_offset;
1479 					err = got_inflate_to_mem_mmap(&base_buf,
1480 					    &base_bufsz, NULL, NULL,
1481 					    pack->map, mapoff,
1482 					    pack->filesize - mapoff);
1483 				} else
1484 					err = got_inflate_to_mem_fd(&base_buf,
1485 					    &base_bufsz, NULL, NULL, max_size,
1486 					    pack->fd);
1487 			}
1488 			if (err)
1489 				goto done;
1490 			n++;
1491 			if (base_buf == NULL)
1492 				rewind(base_file);
1493 			else if (pack->delta_cache && fulltext == NULL) {
1494 				err = got_delta_cache_add(pack->delta_cache,
1495 				    delta_data_offset, NULL, 0);
1496 				if (err) {
1497 					if (err->code != GOT_ERR_NO_SPACE)
1498 						goto done;
1499 					err = NULL;
1500 				} else {
1501 					err = got_delta_cache_add_fulltext(
1502 					    pack->delta_cache,
1503 					    delta_data_offset,
1504 					    base_buf, base_bufsz);
1505 					if (err &&
1506 					    err->code != GOT_ERR_NO_SPACE)
1507 						goto done;
1508 					err = NULL;
1509 				}
1510 			}
1511 			continue;
1512 		}
1513 
1514 		if (pack->delta_cache) {
1515 			got_delta_cache_get(&delta_buf, &delta_len,
1516 			    &fulltext, &fulltext_len,
1517 			    pack->delta_cache, delta->data_offset);
1518 		}
1519 		if (delta_buf == NULL) {
1520 			cached = 0;
1521 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1522 			    delta->data_offset, pack);
1523 			if (err)
1524 				goto done;
1525 		}
1526 		if (pack->delta_cache && !cached) {
1527 			err = got_delta_cache_add(pack->delta_cache,
1528 			    delta->data_offset, delta_buf, delta_len);
1529 			if (err == NULL)
1530 				cached = 1;
1531 			else if (err->code != GOT_ERR_NO_SPACE) {
1532 				free(delta_buf);
1533 				goto done;
1534 			}
1535 		}
1536 
1537 		err = got_delta_get_sizes(&base_size, &result_size,
1538 		    delta_buf, delta_len);
1539 		if (err) {
1540 			if (!cached)
1541 				free(delta_buf);
1542 			goto done;
1543 		}
1544 		if (base_size > max_size)
1545 			max_size = base_size;
1546 		if (result_size > max_size)
1547 			max_size = result_size;
1548 		if (fulltext_len > max_size)
1549 			max_size = fulltext_len;
1550 
1551 		if (base_buf && max_size > max_bufsize) {
1552 			/* Switch from buffers to temporary files. */
1553 			size_t w = fwrite(base_buf, 1, base_bufsz,
1554 			    base_file);
1555 			if (w != base_bufsz) {
1556 				err = got_ferror(outfile, GOT_ERR_IO);
1557 				if (!cached)
1558 					free(delta_buf);
1559 				goto done;
1560 			}
1561 			free(base_buf);
1562 			base_buf = NULL;
1563 			free(accum_buf);
1564 			accum_buf = NULL;
1565 		}
1566 
1567 		if (base_buf && max_size > base_bufsz) {
1568 			uint8_t *p = realloc(base_buf, max_size);
1569 			if (p == NULL) {
1570 				err = got_error_from_errno("realloc");
1571 				if (!cached)
1572 					free(delta_buf);
1573 				goto done;
1574 			}
1575 			base_buf = p;
1576 			base_bufsz = max_size;
1577 		}
1578 
1579 		if (accum_buf && max_size > accum_bufsz) {
1580 			uint8_t *p = realloc(accum_buf, max_size);
1581 			if (p == NULL) {
1582 				err = got_error_from_errno("realloc");
1583 				if (!cached)
1584 					free(delta_buf);
1585 				goto done;
1586 			}
1587 			accum_buf = p;
1588 			accum_bufsz = max_size;
1589 		}
1590 
1591 		if (base_buf) {
1592 			if (fulltext) {
1593 				memcpy(accum_buf, fulltext, fulltext_len);
1594 				accum_size = fulltext_len;
1595 				err = NULL;
1596 			} else {
1597 				err = got_delta_apply_in_mem(base_buf,
1598 				    base_bufsz, delta_buf, delta_len,
1599 				    accum_buf, &accum_size, max_size);
1600 			}
1601 			n++;
1602 			if (!cached)
1603 				free(delta_buf);
1604 			if (err)
1605 				goto done;
1606 			if (fulltext == NULL) {
1607 				err = got_delta_cache_add_fulltext(
1608 				    pack->delta_cache, delta->data_offset,
1609 				    accum_buf, accum_size);
1610 				if (err) {
1611 					if (err->code != GOT_ERR_NO_SPACE)
1612 						goto done;
1613 					err = NULL;
1614 				}
1615 			}
1616 		} else {
1617 			err = got_delta_apply(base_file, delta_buf,
1618 			    delta_len,
1619 			    /* Final delta application writes to output file. */
1620 			    ++n < deltas->nentries ? accum_file : outfile,
1621 			    &accum_size);
1622 			if (!cached)
1623 				free(delta_buf);
1624 			if (err)
1625 				goto done;
1626 		}
1627 
1628 		if (n < deltas->nentries) {
1629 			/* Accumulated delta becomes the new base. */
1630 			if (base_buf) {
1631 				uint8_t *tmp = accum_buf;
1632 				size_t tmp_size = accum_bufsz;
1633 				accum_buf = base_buf;
1634 				accum_bufsz = base_bufsz;
1635 				base_buf = tmp;
1636 				base_bufsz = tmp_size;
1637 			} else {
1638 				FILE *tmp = accum_file;
1639 				accum_file = base_file;
1640 				base_file = tmp;
1641 				rewind(base_file);
1642 				rewind(accum_file);
1643 			}
1644 		}
1645 	}
1646 
1647 done:
1648 	free(base_buf);
1649 	if (accum_buf) {
1650 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1651 		free(accum_buf);
1652 		if (len != accum_size)
1653 			err = got_ferror(outfile, GOT_ERR_IO);
1654 	}
1655 	rewind(outfile);
1656 	if (err == NULL)
1657 		*result_size = accum_size;
1658 	return err;
1659 }
1660 
1661 const struct got_error *
1662 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1663     struct got_delta_chain *deltas, struct got_pack *pack)
1664 {
1665 	const struct got_error *err = NULL;
1666 	struct got_delta *delta;
1667 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1668 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1669 	uint64_t max_size = 0;
1670 	int n = 0;
1671 
1672 	*outbuf = NULL;
1673 	*outlen = 0;
1674 
1675 	if (STAILQ_EMPTY(&deltas->entries))
1676 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1677 
1678 	if (pack->delta_cache) {
1679 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1680 		size_t delta_len, fulltext_len;
1681 
1682 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1683 		got_delta_cache_get(&delta_buf, &delta_len,
1684 		    &fulltext, &fulltext_len,
1685 		    pack->delta_cache, delta->data_offset);
1686 		if (fulltext) {
1687 			*outbuf = malloc(fulltext_len);
1688 			if (*outbuf == NULL)
1689 				return got_error_from_errno("malloc");
1690 			memcpy(*outbuf, fulltext, fulltext_len);
1691 			*outlen = fulltext_len;
1692 			return NULL;
1693 		}
1694 	}
1695 
1696 	/* Deltas are ordered in ascending order. */
1697 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1698 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1699 		size_t delta_len, fulltext_len = 0;
1700 		uint64_t base_size, result_size = 0;
1701 		int cached = 1;
1702 		if (n == 0) {
1703 			off_t delta_data_offset;
1704 
1705 			/* Plain object types are the delta base. */
1706 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1707 			    delta->type != GOT_OBJ_TYPE_TREE &&
1708 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1709 			    delta->type != GOT_OBJ_TYPE_TAG) {
1710 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1711 				goto done;
1712 			}
1713 
1714 			delta_data_offset = delta->offset + delta->tslen;
1715 			if (delta_data_offset >= pack->filesize) {
1716 				err = got_error(GOT_ERR_PACK_OFFSET);
1717 				goto done;
1718 			}
1719 
1720 			if (pack->delta_cache) {
1721 				got_delta_cache_get(&delta_buf, &delta_len,
1722 				    &fulltext, &fulltext_len,
1723 				    pack->delta_cache, delta_data_offset);
1724 			}
1725 
1726 			if (delta->size > max_size)
1727 				max_size = delta->size;
1728 			if (delta->size > fulltext_len)
1729 				max_size = fulltext_len;
1730 
1731 			if (fulltext) {
1732 				base_buf = malloc(fulltext_len);
1733 				if (base_buf == NULL) {
1734 					err = got_error_from_errno("malloc");
1735 					goto done;
1736 				}
1737 				memcpy(base_buf, fulltext, fulltext_len);
1738 				base_bufsz = fulltext_len;
1739 			} else if (pack->map) {
1740 				size_t mapoff;
1741 
1742 				if (delta_data_offset > SIZE_MAX) {
1743 					return got_error_fmt(GOT_ERR_RANGE,
1744 					    "delta %lld offset would "
1745 					    "overflow size_t",
1746 					    (long long)delta_data_offset);
1747 				}
1748 
1749 				mapoff = delta_data_offset;
1750 				err = got_inflate_to_mem_mmap(&base_buf,
1751 				    &base_bufsz, NULL, NULL, pack->map,
1752 				    mapoff, pack->filesize - mapoff);
1753 			} else {
1754 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1755 				    == -1) {
1756 					err = got_error_from_errno("lseek");
1757 					goto done;
1758 				}
1759 				err = got_inflate_to_mem_fd(&base_buf,
1760 				    &base_bufsz, NULL, NULL, max_size,
1761 				    pack->fd);
1762 			}
1763 			if (err)
1764 				goto done;
1765 			n++;
1766 
1767 			if (pack->delta_cache && fulltext == NULL) {
1768 				err = got_delta_cache_add(pack->delta_cache,
1769 				    delta_data_offset, NULL, 0);
1770 				if (err) {
1771 					if (err->code != GOT_ERR_NO_SPACE)
1772 						goto done;
1773 					err = NULL;
1774 				} else {
1775 					err = got_delta_cache_add_fulltext(
1776 					    pack->delta_cache,
1777 					    delta_data_offset,
1778 					    base_buf, base_bufsz);
1779 					if (err &&
1780 					    err->code != GOT_ERR_NO_SPACE)
1781 						goto done;
1782 					err = NULL;
1783 				}
1784 			}
1785 			continue;
1786 		}
1787 
1788 		if (pack->delta_cache) {
1789 			got_delta_cache_get(&delta_buf, &delta_len,
1790 			    &fulltext, &fulltext_len,
1791 			    pack->delta_cache, delta->data_offset);
1792 		}
1793 		if (delta_buf == NULL) {
1794 			cached = 0;
1795 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1796 			    delta->data_offset, pack);
1797 			if (err)
1798 				goto done;
1799 		}
1800 		if (pack->delta_cache && !cached) {
1801 			err = got_delta_cache_add(pack->delta_cache,
1802 			    delta->data_offset, delta_buf, delta_len);
1803 			if (err == NULL)
1804 				cached = 1;
1805 			else if (err->code != GOT_ERR_NO_SPACE) {
1806 				free(delta_buf);
1807 				goto done;
1808 			}
1809 		}
1810 
1811 		err = got_delta_get_sizes(&base_size, &result_size,
1812 		    delta_buf, delta_len);
1813 		if (err) {
1814 			if (!cached)
1815 				free(delta_buf);
1816 			goto done;
1817 		}
1818 		if (base_size > max_size)
1819 			max_size = base_size;
1820 		if (result_size > max_size)
1821 			max_size = result_size;
1822 		if (fulltext_len > max_size)
1823 			max_size = fulltext_len;
1824 
1825 		if (max_size > base_bufsz) {
1826 			uint8_t *p = realloc(base_buf, max_size);
1827 			if (p == NULL) {
1828 				err = got_error_from_errno("realloc");
1829 				if (!cached)
1830 					free(delta_buf);
1831 				goto done;
1832 			}
1833 			base_buf = p;
1834 			base_bufsz = max_size;
1835 		}
1836 
1837 		if (max_size > accum_bufsz) {
1838 			uint8_t *p = realloc(accum_buf, max_size);
1839 			if (p == NULL) {
1840 				err = got_error_from_errno("realloc");
1841 				if (!cached)
1842 					free(delta_buf);
1843 				goto done;
1844 			}
1845 			accum_buf = p;
1846 			accum_bufsz = max_size;
1847 		}
1848 
1849 		if (fulltext) {
1850 			memcpy(accum_buf, fulltext, fulltext_len);
1851 			accum_size = fulltext_len;
1852 			err = NULL;
1853 		} else {
1854 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1855 			    delta_buf, delta_len, accum_buf,
1856 			    &accum_size, max_size);
1857 		}
1858 		if (!cached)
1859 			free(delta_buf);
1860 		n++;
1861 		if (err)
1862 			goto done;
1863 
1864 		if (fulltext == NULL) {
1865 			err = got_delta_cache_add_fulltext(pack->delta_cache,
1866 			    delta->data_offset, accum_buf, accum_size);
1867 			if (err) {
1868 				if (err->code != GOT_ERR_NO_SPACE)
1869 					goto done;
1870 				err = NULL;
1871 			}
1872 		}
1873 
1874 		if (n < deltas->nentries) {
1875 			/* Accumulated delta becomes the new base. */
1876 			uint8_t *tmp = accum_buf;
1877 			size_t tmp_size = accum_bufsz;
1878 			accum_buf = base_buf;
1879 			accum_bufsz = base_bufsz;
1880 			base_buf = tmp;
1881 			base_bufsz = tmp_size;
1882 		}
1883 	}
1884 
1885 done:
1886 	free(base_buf);
1887 	if (err) {
1888 		free(accum_buf);
1889 		*outbuf = NULL;
1890 		*outlen = 0;
1891 	} else {
1892 		*outbuf = accum_buf;
1893 		*outlen = accum_size;
1894 	}
1895 	return err;
1896 }
1897 
1898 const struct got_error *
1899 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1900     FILE *outfile, FILE *base_file, FILE *accum_file)
1901 {
1902 	const struct got_error *err = NULL;
1903 
1904 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1905 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1906 
1907 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1908 		if (obj->pack_offset >= pack->filesize)
1909 			return got_error(GOT_ERR_PACK_OFFSET);
1910 
1911 		if (pack->map) {
1912 			size_t mapoff;
1913 
1914 			if (obj->pack_offset > SIZE_MAX) {
1915 				return got_error_fmt(GOT_ERR_RANGE,
1916 				    "pack offset %lld would overflow size_t",
1917 				    (long long)obj->pack_offset);
1918 			}
1919 
1920 			mapoff = obj->pack_offset;
1921 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1922 			    pack->map, mapoff, pack->filesize - mapoff,
1923 			    outfile);
1924 		} else {
1925 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1926 				return got_error_from_errno("lseek");
1927 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1928 			    pack->fd, outfile);
1929 		}
1930 	} else
1931 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1932 		    &obj->deltas, pack, outfile, base_file, accum_file);
1933 
1934 	return err;
1935 }
1936 
1937 const struct got_error *
1938 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1939     struct got_object *obj, struct got_pack *pack)
1940 {
1941 	const struct got_error *err = NULL;
1942 
1943 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1944 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1945 
1946 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1947 		if (obj->pack_offset >= pack->filesize)
1948 			return got_error(GOT_ERR_PACK_OFFSET);
1949 		if (pack->map) {
1950 			size_t mapoff;
1951 
1952 			if (obj->pack_offset > SIZE_MAX) {
1953 				return got_error_fmt(GOT_ERR_RANGE,
1954 				    "pack offset %lld would overflow size_t",
1955 				    (long long)obj->pack_offset);
1956 			}
1957 
1958 			mapoff = obj->pack_offset;
1959 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1960 			    pack->map, mapoff, pack->filesize - mapoff);
1961 		} else {
1962 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1963 				return got_error_from_errno("lseek");
1964 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1965 			    obj->size, pack->fd);
1966 		}
1967 	} else
1968 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1969 		    pack);
1970 
1971 	return err;
1972 }
1973 
1974 static const struct got_error *
1975 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1976     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1977     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1978 {
1979 	const struct got_error *err = NULL;
1980 
1981 	/* Validate decompression and obtain the decompressed size. */
1982 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1983 	    delta_data_offset, pack);
1984 	if (err)
1985 		return err;
1986 
1987 	/* Read delta base/result sizes from head of delta stream. */
1988 	err = got_delta_get_sizes(base_size, result_size,
1989 	    *delta_buf, *delta_len);
1990 	if (err)
1991 		goto done;
1992 
1993 	/* Discard decompressed delta and read it again in compressed form. */
1994 	free(*delta_buf);
1995 	*delta_buf = malloc(*delta_len_compressed);
1996 	if (*delta_buf == NULL) {
1997 		err = got_error_from_errno("malloc");
1998 		goto done;
1999 	}
2000 	if (pack->map) {
2001 		if (delta_data_offset >= pack->filesize) {
2002 			err = got_error(GOT_ERR_PACK_OFFSET);
2003 			goto done;
2004 		}
2005 		memcpy(*delta_buf, pack->map + delta_data_offset,
2006 		    *delta_len_compressed);
2007 	} else {
2008 		ssize_t n;
2009 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
2010 			err = got_error_from_errno("lseek");
2011 			goto done;
2012 		}
2013 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
2014 		if (n < 0) {
2015 			err = got_error_from_errno("read");
2016 			goto done;
2017 		} else if (n != *delta_len_compressed) {
2018 			err = got_error(GOT_ERR_IO);
2019 			goto done;
2020 		}
2021 	}
2022 done:
2023 	if (err) {
2024 		free(*delta_buf);
2025 		*delta_buf = NULL;
2026 		*delta_len = 0;
2027 		*delta_len_compressed = 0;
2028 		*base_size = 0;
2029 		*result_size = 0;
2030 	}
2031 	return err;
2032 }
2033 
2034 const struct got_error *
2035 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
2036     size_t *delta_compressed_size, off_t *delta_offset,
2037     off_t *delta_data_offset, off_t *base_offset,
2038     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
2039     struct got_pack *pack, struct got_packidx *packidx, int idx)
2040 {
2041 	const struct got_error *err = NULL;
2042 	off_t offset;
2043 	uint8_t type;
2044 	uint64_t size;
2045 	size_t tslen, delta_hdrlen;
2046 
2047 	*delta_buf = NULL;
2048 	*delta_size = 0;
2049 	*delta_compressed_size = 0;
2050 	*delta_offset = 0;
2051 	*delta_data_offset = 0;
2052 	*base_offset = 0;
2053 	*base_size = 0;
2054 	*result_size = 0;
2055 
2056 	offset = got_packidx_get_object_offset(packidx, idx);
2057 	if (offset == -1)
2058 		return got_error(GOT_ERR_BAD_PACKIDX);
2059 
2060 	if (offset >= pack->filesize)
2061 		return got_error(GOT_ERR_PACK_OFFSET);
2062 
2063 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
2064 	    pack, offset);
2065 	if (err)
2066 		return err;
2067 
2068 	if (tslen + size < tslen || offset + size < size ||
2069 	    tslen + offset < tslen)
2070 		return got_error(GOT_ERR_PACK_OFFSET);
2071 
2072 	switch (type) {
2073 	case GOT_OBJ_TYPE_OFFSET_DELTA:
2074 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
2075 		    pack, offset, tslen);
2076 		if (err)
2077 			return err;
2078 		break;
2079 	case GOT_OBJ_TYPE_REF_DELTA:
2080 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
2081 		if (err)
2082 			return err;
2083 		delta_hdrlen = SHA1_DIGEST_LENGTH;
2084 		break;
2085 	default:
2086 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
2087 		    "non-delta object type %d found at offset %lld",
2088 		    type, (long long)offset);
2089 	}
2090 
2091 	if (tslen + delta_hdrlen < delta_hdrlen ||
2092 	    offset + delta_hdrlen < delta_hdrlen)
2093 		return got_error(GOT_ERR_BAD_DELTA);
2094 
2095 	*delta_data_offset = offset + tslen + delta_hdrlen;
2096 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
2097 	    base_size, result_size, *delta_data_offset, pack, packidx);
2098 	if (err)
2099 		return err;
2100 
2101 	if (*delta_size != size) {
2102 		err = got_error(GOT_ERR_BAD_DELTA);
2103 		goto done;
2104 	}
2105 
2106 	*delta_offset = offset;
2107 done:
2108 	if (err) {
2109 		free(*delta_buf);
2110 		*delta_buf = NULL;
2111 		*delta_size = 0;
2112 		*delta_compressed_size = 0;
2113 		*delta_offset = 0;
2114 		*base_offset = 0;
2115 		*base_size = 0;
2116 		*result_size = 0;
2117 	}
2118 	return err;
2119 }