1 /*
2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 #include <sys/uio.h>
21 #include <sys/mman.h>
22 #include <sys/resource.h>
23 #include <sys/socket.h>
24 
25 #include <fcntl.h>
26 #include <errno.h>
27 #include <stdio.h>
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <limits.h>
32 #include <sha1.h>
33 #include <sha2.h>
34 #include <endian.h>
35 #include <unistd.h>
36 #include <zlib.h>
37 #include <imsg.h>
38 
39 #include "got_error.h"
40 #include "got_object.h"
41 #include "got_path.h"
42 
43 #include "got_lib_hash.h"
44 #include "got_lib_delta.h"
45 #include "got_lib_delta_cache.h"
46 #include "got_lib_inflate.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_qid.h"
49 #include "got_lib_object_parse.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_pack.h"
52 
53 #ifndef nitems
54 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
55 #endif
56 
57 #ifndef MIN
58 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
59 #endif
60 
61 static const struct got_error *
62 verify_fanout_table(uint32_t *fanout_table)
63 {
64 	int i;
65 
66 	for (i = 0; i < 0xff - 1; i++) {
67 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
68 			return got_error(GOT_ERR_BAD_PACKIDX);
69 	}
70 
71 	return NULL;
72 }
73 
74 const struct got_error *
75 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
76 {
77 	const struct got_error *err = NULL;
78 	enum got_hash_algorithm algo = GOT_HASH_SHA1;
79 	struct got_packidx_v2_hdr *h;
80 	struct got_hash ctx;
81 	uint8_t hash[GOT_HASH_DIGEST_MAXLEN];
82 	size_t nobj, len_fanout, len_ids, offset, remain;
83 	ssize_t n;
84 	int i;
85 
86 	got_hash_init(&ctx, algo);
87 
88 	h = &p->hdr;
89 	offset = 0;
90 	remain = p->len;
91 
92 	if (remain < sizeof(*h->magic)) {
93 		err = got_error(GOT_ERR_BAD_PACKIDX);
94 		goto done;
95 	}
96 	if (p->map)
97 		h->magic = (uint32_t *)(p->map + offset);
98 	else {
99 		h->magic = malloc(sizeof(*h->magic));
100 		if (h->magic == NULL) {
101 			err = got_error_from_errno("malloc");
102 			goto done;
103 		}
104 		n = read(p->fd, h->magic, sizeof(*h->magic));
105 		if (n < 0) {
106 			err = got_error_from_errno("read");
107 			goto done;
108 		} else if (n != sizeof(*h->magic)) {
109 			err = got_error(GOT_ERR_BAD_PACKIDX);
110 			goto done;
111 		}
112 	}
113 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
114 		err = got_error(GOT_ERR_BAD_PACKIDX);
115 		goto done;
116 	}
117 	offset += sizeof(*h->magic);
118 	remain -= sizeof(*h->magic);
119 
120 	if (verify)
121 		got_hash_update(&ctx, h->magic, sizeof(*h->magic));
122 
123 	if (remain < sizeof(*h->version)) {
124 		err = got_error(GOT_ERR_BAD_PACKIDX);
125 		goto done;
126 	}
127 	if (p->map)
128 		h->version = (uint32_t *)(p->map + offset);
129 	else {
130 		h->version = malloc(sizeof(*h->version));
131 		if (h->version == NULL) {
132 			err = got_error_from_errno("malloc");
133 			goto done;
134 		}
135 		n = read(p->fd, h->version, sizeof(*h->version));
136 		if (n < 0) {
137 			err = got_error_from_errno("read");
138 			goto done;
139 		} else if (n != sizeof(*h->version)) {
140 			err = got_error(GOT_ERR_BAD_PACKIDX);
141 			goto done;
142 		}
143 	}
144 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
145 		err = got_error(GOT_ERR_BAD_PACKIDX);
146 		goto done;
147 	}
148 	offset += sizeof(*h->version);
149 	remain -= sizeof(*h->version);
150 
151 	if (verify)
152 		got_hash_update(&ctx, h->version, sizeof(*h->version));
153 
154 	len_fanout =
155 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
156 	if (remain < len_fanout) {
157 		err = got_error(GOT_ERR_BAD_PACKIDX);
158 		goto done;
159 	}
160 	if (p->map)
161 		h->fanout_table = (uint32_t *)(p->map + offset);
162 	else {
163 		h->fanout_table = malloc(len_fanout);
164 		if (h->fanout_table == NULL) {
165 			err = got_error_from_errno("malloc");
166 			goto done;
167 		}
168 		n = read(p->fd, h->fanout_table, len_fanout);
169 		if (n < 0) {
170 			err = got_error_from_errno("read");
171 			goto done;
172 		} else if (n != len_fanout) {
173 			err = got_error(GOT_ERR_BAD_PACKIDX);
174 			goto done;
175 		}
176 	}
177 	err = verify_fanout_table(h->fanout_table);
178 	if (err)
179 		goto done;
180 	if (verify)
181 		got_hash_update(&ctx, h->fanout_table, len_fanout);
182 	offset += len_fanout;
183 	remain -= len_fanout;
184 
185 	nobj = be32toh(h->fanout_table[0xff]);
186 	len_ids = nobj * sizeof(*h->sorted_ids);
187 	if (len_ids <= nobj || len_ids > remain) {
188 		err = got_error(GOT_ERR_BAD_PACKIDX);
189 		goto done;
190 	}
191 	if (p->map)
192 		h->sorted_ids =
193 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
194 	else {
195 		h->sorted_ids = malloc(len_ids);
196 		if (h->sorted_ids == NULL) {
197 			err = got_error(GOT_ERR_BAD_PACKIDX);
198 			goto done;
199 		}
200 		n = read(p->fd, h->sorted_ids, len_ids);
201 		if (n < 0)
202 			err = got_error_from_errno("read");
203 		else if (n != len_ids) {
204 			err = got_error(GOT_ERR_BAD_PACKIDX);
205 			goto done;
206 		}
207 	}
208 	if (verify)
209 		got_hash_update(&ctx, h->sorted_ids, len_ids);
210 	offset += len_ids;
211 	remain -= len_ids;
212 
213 	if (remain < nobj * sizeof(*h->crc32)) {
214 		err = got_error(GOT_ERR_BAD_PACKIDX);
215 		goto done;
216 	}
217 	if (p->map)
218 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
219 	else {
220 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
221 		if (h->crc32 == NULL) {
222 			err = got_error_from_errno("malloc");
223 			goto done;
224 		}
225 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
226 		if (n < 0)
227 			err = got_error_from_errno("read");
228 		else if (n != nobj * sizeof(*h->crc32)) {
229 			err = got_error(GOT_ERR_BAD_PACKIDX);
230 			goto done;
231 		}
232 	}
233 	if (verify)
234 		got_hash_update(&ctx, h->crc32, nobj * sizeof(*h->crc32));
235 	remain -= nobj * sizeof(*h->crc32);
236 	offset += nobj * sizeof(*h->crc32);
237 
238 	if (remain < nobj * sizeof(*h->offsets)) {
239 		err = got_error(GOT_ERR_BAD_PACKIDX);
240 		goto done;
241 	}
242 	if (p->map)
243 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
244 	else {
245 		h->offsets = malloc(nobj * sizeof(*h->offsets));
246 		if (h->offsets == NULL) {
247 			err = got_error_from_errno("malloc");
248 			goto done;
249 		}
250 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
251 		if (n < 0)
252 			err = got_error_from_errno("read");
253 		else if (n != nobj * sizeof(*h->offsets)) {
254 			err = got_error(GOT_ERR_BAD_PACKIDX);
255 			goto done;
256 		}
257 	}
258 	if (verify)
259 		got_hash_update(&ctx, h->offsets, nobj * sizeof(*h->offsets));
260 	remain -= nobj * sizeof(*h->offsets);
261 	offset += nobj * sizeof(*h->offsets);
262 
263 	/* Large file offsets are contained only in files > 2GB. */
264 	if (verify || packfile_size > 0x7fffffff) {
265 		for (i = 0; i < nobj; i++) {
266 			uint32_t o = h->offsets[i];
267 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
268 				p->nlargeobj++;
269 		}
270 	}
271 	if (p->nlargeobj == 0)
272 		goto checksum;
273 	else if (packfile_size <= 0x7fffffff) {
274 		err = got_error(GOT_ERR_BAD_PACKIDX);
275 		goto done;
276 	}
277 
278 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
279 		err = got_error(GOT_ERR_BAD_PACKIDX);
280 		goto done;
281 	}
282 	if (p->map)
283 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
284 	else {
285 		h->large_offsets = malloc(p->nlargeobj *
286 		    sizeof(*h->large_offsets));
287 		if (h->large_offsets == NULL) {
288 			err = got_error_from_errno("malloc");
289 			goto done;
290 		}
291 		n = read(p->fd, h->large_offsets,
292 		    p->nlargeobj * sizeof(*h->large_offsets));
293 		if (n < 0)
294 			err = got_error_from_errno("read");
295 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
296 			err = got_error(GOT_ERR_BAD_PACKIDX);
297 			goto done;
298 		}
299 	}
300 	if (verify)
301 		got_hash_update(&ctx, h->large_offsets,
302 		    p->nlargeobj * sizeof(*h->large_offsets));
303 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
304 	offset += p->nlargeobj * sizeof(*h->large_offsets);
305 
306 checksum:
307 	if (remain < sizeof(*h->trailer)) {
308 		err = got_error(GOT_ERR_BAD_PACKIDX);
309 		goto done;
310 	}
311 	if (p->map)
312 		h->trailer =
313 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
314 	else {
315 		h->trailer = malloc(sizeof(*h->trailer));
316 		if (h->trailer == NULL) {
317 			err = got_error_from_errno("malloc");
318 			goto done;
319 		}
320 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
321 		if (n < 0)
322 			err = got_error_from_errno("read");
323 		else if (n != sizeof(*h->trailer)) {
324 			err = got_error(GOT_ERR_BAD_PACKIDX);
325 			goto done;
326 		}
327 	}
328 	if (verify) {
329 		got_hash_update(&ctx, h->trailer->packfile_sha1,
330 		    SHA1_DIGEST_LENGTH);
331 		got_hash_final(&ctx, hash);
332 		if (got_hash_cmp(ctx.algo, hash, h->trailer->packidx_sha1) != 0)
333 			err = got_error(GOT_ERR_PACKIDX_CSUM);
334 	}
335 done:
336 	return err;
337 }
338 
339 const struct got_error *
340 got_packidx_open(struct got_packidx **packidx,
341     int dir_fd, const char *relpath, int verify)
342 {
343 	const struct got_error *err = NULL;
344 	struct got_packidx *p = NULL;
345 	char *pack_relpath;
346 	struct stat idx_sb, pack_sb;
347 
348 	*packidx = NULL;
349 
350 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
351 	if (err)
352 		return err;
353 
354 	/*
355 	 * Ensure that a corresponding pack file exists.
356 	 * Some Git repositories have this problem. Git seems to ignore
357 	 * the existence of lonely pack index files but we do not.
358 	 */
359 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
360 		if (errno == ENOENT) {
361 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
362 			    "%s", relpath);
363 		} else
364 			err = got_error_from_errno2("fstatat", pack_relpath);
365 		goto done;
366 	}
367 
368 	p = calloc(1, sizeof(*p));
369 	if (p == NULL) {
370 		err = got_error_from_errno("calloc");
371 		goto done;
372 	}
373 
374 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
375 	if (p->fd == -1) {
376 		err = got_error_from_errno2("openat", relpath);
377 		goto done;
378 	}
379 
380 	if (fstat(p->fd, &idx_sb) != 0) {
381 		err = got_error_from_errno2("fstat", relpath);
382 		goto done;
383 	}
384 	p->len = idx_sb.st_size;
385 	if (p->len < sizeof(p->hdr)) {
386 		err = got_error(GOT_ERR_BAD_PACKIDX);
387 		goto done;
388 	}
389 
390 	p->path_packidx = strdup(relpath);
391 	if (p->path_packidx == NULL) {
392 		err = got_error_from_errno("strdup");
393 		goto done;
394 	}
395 
396 #ifndef GOT_PACK_NO_MMAP
397 	if (p->len > 0 && p->len <= SIZE_MAX) {
398 		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
399 		if (p->map == MAP_FAILED) {
400 			if (errno != ENOMEM) {
401 				err = got_error_from_errno("mmap");
402 				goto done;
403 			}
404 			p->map = NULL; /* fall back to read(2) */
405 		}
406 	}
407 #endif
408 
409 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
410 done:
411 	if (err) {
412 		if (p)
413 			got_packidx_close(p);
414 	} else
415 		*packidx = p;
416 	free(pack_relpath);
417 	return err;
418 }
419 
420 const struct got_error *
421 got_packidx_close(struct got_packidx *packidx)
422 {
423 	const struct got_error *err = NULL;
424 
425 	free(packidx->path_packidx);
426 	if (packidx->map) {
427 		if (munmap(packidx->map, packidx->len) == -1)
428 			err = got_error_from_errno("munmap");
429 	} else {
430 		free(packidx->hdr.magic);
431 		free(packidx->hdr.version);
432 		free(packidx->hdr.fanout_table);
433 		free(packidx->hdr.sorted_ids);
434 		free(packidx->hdr.crc32);
435 		free(packidx->hdr.offsets);
436 		free(packidx->hdr.large_offsets);
437 		free(packidx->hdr.trailer);
438 	}
439 	if (close(packidx->fd) == -1 && err == NULL)
440 		err = got_error_from_errno("close");
441 	free(packidx->sorted_offsets);
442 	free(packidx->sorted_large_offsets);
443 	free(packidx);
444 
445 	return err;
446 }
447 
448 const struct got_error *
449 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
450 {
451 	size_t size;
452 
453 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
454 	size = strlen(path_packidx) + 2;
455 	if (size < GOT_PACKFILE_NAMELEN + 1)
456 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
457 
458 	*path_packfile = malloc(size);
459 	if (*path_packfile == NULL)
460 		return got_error_from_errno("malloc");
461 
462 	/* Copy up to and excluding ".idx". */
463 	if (strlcpy(*path_packfile, path_packidx,
464 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
465 		return got_error(GOT_ERR_NO_SPACE);
466 
467 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
468 		return got_error(GOT_ERR_NO_SPACE);
469 
470 	return NULL;
471 }
472 
473 off_t
474 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
475 {
476 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
477 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
478 		uint64_t loffset;
479 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
480 		if (idx < 0 || idx >= packidx->nlargeobj ||
481 		    packidx->hdr.large_offsets == NULL)
482 			return -1;
483 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
484 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
485 	}
486 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
487 }
488 
489 int
490 got_packidx_get_object_idx(struct got_packidx *packidx,
491     struct got_object_id *id)
492 {
493 	u_int8_t id0 = id->sha1[0];
494 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
495 	int left = 0, right = totobj - 1;
496 
497 	if (id0 > 0)
498 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
499 
500 	while (left <= right) {
501 		struct got_packidx_object_id *oid;
502 		int i, cmp;
503 
504 		i = ((left + right) / 2);
505 		oid = &packidx->hdr.sorted_ids[i];
506 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
507 		if (cmp == 0)
508 			return i;
509 		else if (cmp > 0)
510 			left = i + 1;
511 		else if (cmp < 0)
512 			right = i - 1;
513 	}
514 
515 	return -1;
516 }
517 
518 static int
519 offset_cmp(const void *pa, const void *pb)
520 {
521 	const struct got_pack_offset_index *a, *b;
522 
523 	a = (const struct got_pack_offset_index *)pa;
524 	b = (const struct got_pack_offset_index *)pb;
525 
526 	if (a->offset < b->offset)
527 		return -1;
528 	else if (a->offset > b->offset)
529 		return 1;
530 
531 	return 0;
532 }
533 
534 static int
535 large_offset_cmp(const void *pa, const void *pb)
536 {
537 	const struct got_pack_large_offset_index *a, *b;
538 
539 	a = (const struct got_pack_large_offset_index *)pa;
540 	b = (const struct got_pack_large_offset_index *)pb;
541 
542 	if (a->offset < b->offset)
543 		return -1;
544 	else if (a->offset > b->offset)
545 		return 1;
546 
547 	return 0;
548 }
549 
550 static const struct got_error *
551 build_offset_index(struct got_packidx *p)
552 {
553 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
554 	unsigned int i, j, k;
555 
556 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
557 	    sizeof(p->sorted_offsets[0]));
558 	if (p->sorted_offsets == NULL)
559 		return got_error_from_errno("calloc");
560 
561 	if (p->nlargeobj > 0) {
562 		p->sorted_large_offsets = calloc(p->nlargeobj,
563 		    sizeof(p->sorted_large_offsets[0]));
564 		if (p->sorted_large_offsets == NULL)
565 			return got_error_from_errno("calloc");
566 	}
567 
568 	j = 0;
569 	k = 0;
570 	for (i = 0; i < nobj; i++) {
571 		uint32_t offset = be32toh(p->hdr.offsets[i]);
572 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
573 			uint64_t loffset;
574 			uint32_t idx;
575 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
576 			if (idx >= p->nlargeobj ||
577 			    p->nlargeobj == 0 ||
578 			    p->hdr.large_offsets == NULL)
579 				return got_error(GOT_ERR_BAD_PACKIDX);
580 			loffset = be64toh(p->hdr.large_offsets[idx]);
581 			p->sorted_large_offsets[j].offset = loffset;
582 			p->sorted_large_offsets[j].idx = i;
583 			j++;
584 		} else {
585 			p->sorted_offsets[k].offset = offset;
586 			p->sorted_offsets[k].idx = i;
587 			k++;
588 		}
589 	}
590 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
591 		return got_error(GOT_ERR_BAD_PACKIDX);
592 
593 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
594 	    sizeof(p->sorted_offsets[0]), offset_cmp);
595 
596 	if (p->sorted_large_offsets)
597 		qsort(p->sorted_large_offsets, p->nlargeobj,
598 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
599 
600 	return NULL;
601 }
602 
603 const struct got_error *
604 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
605 {
606 	const struct got_error *err;
607 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
608 	int i, left, right;
609 
610 	*idx = -1;
611 
612 	if (packidx->sorted_offsets == NULL) {
613 		err = build_offset_index(packidx);
614 		if (err)
615 			return err;
616 	}
617 
618 	if (offset >= 0x7fffffff) {
619 		uint64_t lo;
620 		left = 0, right = packidx->nlargeobj - 1;
621 		while (left <= right) {
622 			i = ((left + right) / 2);
623 			lo = packidx->sorted_large_offsets[i].offset;
624 			if (lo == offset) {
625 				*idx = packidx->sorted_large_offsets[i].idx;
626 				break;
627 			} else if (offset > lo)
628 				left = i + 1;
629 			else if (offset < lo)
630 				right = i - 1;
631 		}
632 	} else {
633 		uint32_t o;
634 		left = 0, right = totobj - packidx->nlargeobj - 1;
635 		while (left <= right) {
636 			i = ((left + right) / 2);
637 			o = packidx->sorted_offsets[i].offset;
638 			if (o == offset) {
639 				*idx = packidx->sorted_offsets[i].idx;
640 				break;
641 			} else if (offset > o)
642 				left = i + 1;
643 			else if (offset < o)
644 				right = i - 1;
645 		}
646 	}
647 
648 	return NULL;
649 }
650 
651 const struct got_error *
652 got_packidx_get_object_id(struct got_object_id *id,
653     struct got_packidx *packidx, int idx)
654 {
655 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
656 	struct got_packidx_object_id *oid;
657 
658 	if (idx < 0 || idx >= totobj)
659 		return got_error(GOT_ERR_NO_OBJ);
660 
661 	oid = &packidx->hdr.sorted_ids[idx];
662 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
663 	return NULL;
664 }
665 
666 const struct got_error *
667 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
668     struct got_packidx *packidx, const char *id_str_prefix)
669 {
670 	const struct got_error *err = NULL;
671 	u_int8_t id0;
672 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
673 	char hex[3];
674 	size_t prefix_len = strlen(id_str_prefix);
675 	struct got_packidx_object_id *oid;
676 	uint32_t i = 0;
677 
678 	if (prefix_len < 2)
679 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
680 
681 	hex[0] = id_str_prefix[0];
682 	hex[1] = id_str_prefix[1];
683 	hex[2] = '\0';
684 	if (!got_parse_xdigit(&id0, hex))
685 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
686 
687 	if (id0 > 0)
688 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
689 	oid = &packidx->hdr.sorted_ids[i];
690 	while (i < totobj && oid->sha1[0] == id0) {
691 		char id_str[SHA1_DIGEST_STRING_LENGTH];
692 		struct got_object_qid *qid;
693 		int cmp;
694 
695 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
696 			return got_error(GOT_ERR_NO_SPACE);
697 
698 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
699 		if (cmp < 0) {
700 			oid = &packidx->hdr.sorted_ids[++i];
701 			continue;
702 		} else if (cmp > 0)
703 			break;
704 
705 		err = got_object_qid_alloc_partial(&qid);
706 		if (err)
707 			return err;
708 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
709 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
710 
711 		oid = &packidx->hdr.sorted_ids[++i];
712 	}
713 
714 	return NULL;
715 }
716 
717 static void
718 set_max_datasize(void)
719 {
720 	struct rlimit rl;
721 
722 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
723 		return;
724 
725 	rl.rlim_cur = rl.rlim_max;
726 	setrlimit(RLIMIT_DATA, &rl);
727 }
728 
729 const struct got_error *
730 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
731 {
732 	const struct got_error *err = NULL;
733 	int imsg_fds[2];
734 	pid_t pid;
735 	struct imsgbuf *ibuf;
736 
737 	ibuf = calloc(1, sizeof(*ibuf));
738 	if (ibuf == NULL)
739 		return got_error_from_errno("calloc");
740 
741 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
742 	if (pack->privsep_child == NULL) {
743 		err = got_error_from_errno("calloc");
744 		free(ibuf);
745 		return err;
746 	}
747 	pack->child_has_tempfiles = 0;
748 	pack->child_has_delta_outfd = 0;
749 
750 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
751 		err = got_error_from_errno("socketpair");
752 		goto done;
753 	}
754 
755 	pid = fork();
756 	if (pid == -1) {
757 		err = got_error_from_errno("fork");
758 		goto done;
759 	} else if (pid == 0) {
760 		set_max_datasize();
761 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
762 		    pack->path_packfile);
763 		/* not reached */
764 	}
765 
766 	if (close(imsg_fds[1]) == -1)
767 		return got_error_from_errno("close");
768 	pack->privsep_child->imsg_fd = imsg_fds[0];
769 	pack->privsep_child->pid = pid;
770 	imsg_init(ibuf, imsg_fds[0]);
771 	pack->privsep_child->ibuf = ibuf;
772 
773 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
774 	if (err) {
775 		const struct got_error *child_err;
776 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
777 		child_err = got_privsep_wait_for_child(
778 		    pack->privsep_child->pid);
779 		if (child_err && err == NULL)
780 			err = child_err;
781 	}
782 done:
783 	if (err) {
784 		free(ibuf);
785 		free(pack->privsep_child);
786 		pack->privsep_child = NULL;
787 	}
788 	return err;
789 }
790 
791 static const struct got_error *
792 pack_stop_privsep_child(struct got_pack *pack)
793 {
794 	const struct got_error *err = NULL, *close_err = NULL;
795 
796 	if (pack->privsep_child == NULL)
797 		return NULL;
798 
799 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
800 	if (err)
801 		return err;
802 	if (close(pack->privsep_child->imsg_fd) == -1)
803 		close_err = got_error_from_errno("close");
804 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
805 	if (close_err && err == NULL)
806 		err = close_err;
807 	imsg_clear(pack->privsep_child->ibuf);
808 	free(pack->privsep_child->ibuf);
809 	free(pack->privsep_child);
810 	pack->privsep_child = NULL;
811 	return err;
812 }
813 
814 const struct got_error *
815 got_pack_close(struct got_pack *pack)
816 {
817 	const struct got_error *err = NULL;
818 
819 	err = pack_stop_privsep_child(pack);
820 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
821 		err = got_error_from_errno("munmap");
822 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
823 		err = got_error_from_errno("close");
824 	pack->fd = -1;
825 	free(pack->path_packfile);
826 	pack->path_packfile = NULL;
827 	pack->filesize = 0;
828 	if (pack->delta_cache) {
829 		got_delta_cache_free(pack->delta_cache);
830 		pack->delta_cache = NULL;
831 	}
832 
833 	/*
834 	 * Leave accumfd and basefd alone. They are managed by the
835 	 * repository layer and can be reused.
836 	 */
837 
838 	return err;
839 }
840 
841 const struct got_error *
842 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
843     struct got_pack *pack, off_t offset)
844 {
845 	uint8_t t = 0;
846 	uint64_t s = 0;
847 	uint8_t sizeN;
848 	size_t mapoff = 0;
849 	int i = 0;
850 
851 	*len = 0;
852 
853 	if (offset >= pack->filesize)
854 		return got_error(GOT_ERR_PACK_OFFSET);
855 
856 	if (pack->map) {
857 		if (offset > SIZE_MAX) {
858 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
859 			    "offset %lld overflows size_t",
860 			    (long long)offset);
861 		}
862 
863 		mapoff = (size_t)offset;
864 	} else {
865 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
866 			return got_error_from_errno("lseek");
867 	}
868 
869 	do {
870 		/* We do not support size values which don't fit in 64 bit. */
871 		if (i > 9)
872 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
873 			    "packfile offset %lld", (long long)offset);
874 
875 		if (pack->map) {
876 			if (mapoff + sizeof(sizeN) >= pack->filesize)
877 				return got_error(GOT_ERR_BAD_PACKFILE);
878 			sizeN = *(pack->map + mapoff);
879 			mapoff += sizeof(sizeN);
880 		} else {
881 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
882 			if (n < 0)
883 				return got_error_from_errno("read");
884 			if (n != sizeof(sizeN))
885 				return got_error(GOT_ERR_BAD_PACKFILE);
886 		}
887 		*len += sizeof(sizeN);
888 
889 		if (i == 0) {
890 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
891 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
892 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
893 		} else {
894 			size_t shift = 4 + 7 * (i - 1);
895 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
896 		}
897 		i++;
898 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
899 
900 	*type = t;
901 	*size = s;
902 	return NULL;
903 }
904 
905 static const struct got_error *
906 open_plain_object(struct got_object **obj, struct got_object_id *id,
907     uint8_t type, off_t offset, size_t size, int idx)
908 {
909 	*obj = calloc(1, sizeof(**obj));
910 	if (*obj == NULL)
911 		return got_error_from_errno("calloc");
912 
913 	(*obj)->type = type;
914 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
915 	(*obj)->pack_idx = idx;
916 	(*obj)->hdrlen = 0;
917 	(*obj)->size = size;
918 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
919 	(*obj)->pack_offset = offset;
920 
921 	return NULL;
922 }
923 
924 static const struct got_error *
925 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
926     off_t delta_offset)
927 {
928 	int64_t o = 0;
929 	uint8_t offN;
930 	int i = 0;
931 
932 	*offset = 0;
933 	*len = 0;
934 
935 	do {
936 		/* We do not support offset values which don't fit in 64 bit. */
937 		if (i > 8)
938 			return got_error(GOT_ERR_NO_SPACE);
939 
940 		if (pack->map) {
941 			size_t mapoff;
942 
943 			if (delta_offset + *len > SIZE_MAX) {
944 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
945 				    "mapoff %lld would overflow size_t",
946 				    (long long)delta_offset + *len);
947 			}
948 
949 			mapoff = (size_t)delta_offset + *len;
950 			if (mapoff + sizeof(offN) >= pack->filesize)
951 				return got_error(GOT_ERR_PACK_OFFSET);
952 			offN = *(pack->map + mapoff);
953 		} else {
954 			ssize_t n;
955 			n = read(pack->fd, &offN, sizeof(offN));
956 			if (n < 0)
957 				return got_error_from_errno("read");
958 			if (n != sizeof(offN))
959 				return got_error(GOT_ERR_BAD_PACKFILE);
960 		}
961 		*len += sizeof(offN);
962 
963 		if (i == 0)
964 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
965 		else {
966 			o++;
967 			o <<= 7;
968 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
969 		}
970 		i++;
971 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
972 
973 	*offset = o;
974 	return NULL;
975 }
976 
977 const struct got_error *
978 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
979     struct got_pack *pack, off_t offset, size_t tslen)
980 {
981 	const struct got_error *err;
982 	int64_t negoffset;
983 	size_t negofflen;
984 
985 	*len = 0;
986 
987 	err = parse_negative_offset(&negoffset, &negofflen, pack,
988 	    offset + tslen);
989 	if (err)
990 		return err;
991 
992 	/* Compute the base object's offset (must be in the same pack file). */
993 	*base_offset = (offset - negoffset);
994 	if (*base_offset <= 0)
995 		return got_error(GOT_ERR_BAD_PACKFILE);
996 
997 	*len = negofflen;
998 	return NULL;
999 }
1000 
1001 static const struct got_error *
1002 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1003     size_t *delta_compressed_len, size_t delta_data_offset,
1004     struct got_pack *pack)
1005 {
1006 	const struct got_error *err = NULL;
1007 	size_t consumed = 0;
1008 
1009 	if (pack->map) {
1010 		if (delta_data_offset >= pack->filesize)
1011 			return got_error(GOT_ERR_PACK_OFFSET);
1012 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1013 		    &consumed, NULL, pack->map, delta_data_offset,
1014 		    pack->filesize - delta_data_offset);
1015 		if (err)
1016 			return err;
1017 	} else {
1018 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1019 			return got_error_from_errno("lseek");
1020 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1021 		    &consumed, NULL, 0, pack->fd);
1022 		if (err)
1023 			return err;
1024 	}
1025 
1026 	if (delta_compressed_len)
1027 		*delta_compressed_len = consumed;
1028 
1029 	return NULL;
1030 }
1031 
1032 static const struct got_error *
1033 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1034     int delta_type, size_t delta_size, off_t delta_data_offset)
1035 {
1036 	struct got_delta *delta;
1037 
1038 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1039 	    delta_data_offset);
1040 	if (delta == NULL)
1041 		return got_error_from_errno("got_delta_open");
1042 	/* delta is freed in got_object_close() */
1043 	deltas->nentries++;
1044 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1045 	return NULL;
1046 }
1047 
1048 static const struct got_error *
1049 resolve_offset_delta(struct got_delta_chain *deltas,
1050     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1051     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1052 {
1053 	const struct got_error *err;
1054 	off_t base_offset;
1055 	uint8_t base_type;
1056 	uint64_t base_size;
1057 	size_t base_tslen;
1058 	off_t delta_data_offset;
1059 	size_t consumed;
1060 
1061 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1062 	    delta_offset, tslen);
1063 	if (err)
1064 		return err;
1065 
1066 	delta_data_offset = delta_offset + tslen + consumed;
1067 	if (delta_data_offset >= pack->filesize)
1068 		return got_error(GOT_ERR_PACK_OFFSET);
1069 
1070 	if (pack->map == NULL) {
1071 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1072 		if (delta_data_offset == -1)
1073 			return got_error_from_errno("lseek");
1074 	}
1075 
1076 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1077 	    delta_data_offset);
1078 	if (err)
1079 		return err;
1080 
1081 	/* An offset delta must be in the same packfile. */
1082 	if (base_offset >= pack->filesize)
1083 		return got_error(GOT_ERR_PACK_OFFSET);
1084 
1085 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1086 	    &base_tslen, pack, base_offset);
1087 	if (err)
1088 		return err;
1089 
1090 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1091 	    base_tslen, base_type, base_size, recursion - 1);
1092 }
1093 
1094 const struct got_error *
1095 got_pack_parse_ref_delta(struct got_object_id *id,
1096     struct got_pack *pack, off_t delta_offset, int tslen)
1097 {
1098 	if (pack->map) {
1099 		size_t mapoff;
1100 
1101 		if (delta_offset + tslen > SIZE_MAX) {
1102 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1103 			    "mapoff %lld would overflow size_t",
1104 			    (long long)delta_offset + tslen);
1105 		}
1106 
1107 		mapoff = delta_offset + tslen;
1108 		if (mapoff + sizeof(*id) >= pack->filesize)
1109 			return got_error(GOT_ERR_PACK_OFFSET);
1110 		memcpy(id, pack->map + mapoff, sizeof(*id));
1111 	} else {
1112 		ssize_t n;
1113 		n = read(pack->fd, id, sizeof(*id));
1114 		if (n < 0)
1115 			return got_error_from_errno("read");
1116 		if (n != sizeof(*id))
1117 			return got_error(GOT_ERR_BAD_PACKFILE);
1118 	}
1119 
1120 	return NULL;
1121 }
1122 
1123 static const struct got_error *
1124 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1125     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1126     size_t delta_size, unsigned int recursion)
1127 {
1128 	const struct got_error *err;
1129 	struct got_object_id id;
1130 	int idx;
1131 	off_t base_offset;
1132 	uint8_t base_type;
1133 	uint64_t base_size;
1134 	size_t base_tslen;
1135 	off_t delta_data_offset;
1136 
1137 	if (delta_offset + tslen >= pack->filesize)
1138 		return got_error(GOT_ERR_PACK_OFFSET);
1139 
1140 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1141 	if (err)
1142 		return err;
1143 	if (pack->map) {
1144 		delta_data_offset = delta_offset + tslen + SHA1_DIGEST_LENGTH;
1145 	} else {
1146 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1147 		if (delta_data_offset == -1)
1148 			return got_error_from_errno("lseek");
1149 	}
1150 
1151 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1152 	    delta_data_offset);
1153 	if (err)
1154 		return err;
1155 
1156 	/* Delta base must be in the same pack file. */
1157 	idx = got_packidx_get_object_idx(packidx, &id);
1158 	if (idx == -1)
1159 		return got_error(GOT_ERR_NO_OBJ);
1160 
1161 	base_offset = got_packidx_get_object_offset(packidx, idx);
1162 	if (base_offset == -1)
1163 		return got_error(GOT_ERR_BAD_PACKIDX);
1164 
1165 	if (base_offset >= pack->filesize)
1166 		return got_error(GOT_ERR_PACK_OFFSET);
1167 
1168 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1169 	    &base_tslen, pack, base_offset);
1170 	if (err)
1171 		return err;
1172 
1173 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1174 	    base_tslen, base_type, base_size, recursion - 1);
1175 }
1176 
1177 const struct got_error *
1178 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1179     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1180     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1181 {
1182 	const struct got_error *err = NULL;
1183 
1184 	if (--recursion == 0)
1185 		return got_error(GOT_ERR_RECURSION);
1186 
1187 	switch (delta_type) {
1188 	case GOT_OBJ_TYPE_COMMIT:
1189 	case GOT_OBJ_TYPE_TREE:
1190 	case GOT_OBJ_TYPE_BLOB:
1191 	case GOT_OBJ_TYPE_TAG:
1192 		/* Plain types are the final delta base. Recursion ends. */
1193 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1194 		    delta_size, 0);
1195 		break;
1196 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1197 		err = resolve_offset_delta(deltas, packidx, pack,
1198 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1199 		break;
1200 	case GOT_OBJ_TYPE_REF_DELTA:
1201 		err = resolve_ref_delta(deltas, packidx, pack,
1202 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1203 		break;
1204 	default:
1205 		return got_error(GOT_ERR_OBJ_TYPE);
1206 	}
1207 
1208 	return err;
1209 }
1210 
1211 static const struct got_error *
1212 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1213     struct got_pack *pack, struct got_object_id *id, off_t offset,
1214     size_t tslen, int delta_type, size_t delta_size, int idx)
1215 {
1216 	const struct got_error *err = NULL;
1217 	int resolved_type;
1218 
1219 	*obj = calloc(1, sizeof(**obj));
1220 	if (*obj == NULL)
1221 		return got_error_from_errno("calloc");
1222 
1223 	(*obj)->flags = 0;
1224 	(*obj)->hdrlen = 0;
1225 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1226 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1227 	(*obj)->pack_offset = offset + tslen;
1228 
1229 	STAILQ_INIT(&(*obj)->deltas.entries);
1230 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1231 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1232 	(*obj)->pack_idx = idx;
1233 
1234 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1235 	    offset, tslen, delta_type, delta_size,
1236 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1237 	if (err)
1238 		goto done;
1239 
1240 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1241 	if (err)
1242 		goto done;
1243 	(*obj)->type = resolved_type;
1244 done:
1245 	if (err) {
1246 		got_object_close(*obj);
1247 		*obj = NULL;
1248 	}
1249 	return err;
1250 }
1251 
1252 const struct got_error *
1253 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1254     struct got_packidx *packidx, int idx, struct got_object_id *id)
1255 {
1256 	const struct got_error *err = NULL;
1257 	off_t offset;
1258 	uint8_t type;
1259 	uint64_t size;
1260 	size_t tslen;
1261 
1262 	*obj = NULL;
1263 
1264 	offset = got_packidx_get_object_offset(packidx, idx);
1265 	if (offset == -1)
1266 		return got_error(GOT_ERR_BAD_PACKIDX);
1267 
1268 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1269 	    pack, offset);
1270 	if (err)
1271 		return err;
1272 
1273 	switch (type) {
1274 	case GOT_OBJ_TYPE_COMMIT:
1275 	case GOT_OBJ_TYPE_TREE:
1276 	case GOT_OBJ_TYPE_BLOB:
1277 	case GOT_OBJ_TYPE_TAG:
1278 		err = open_plain_object(obj, id, type, offset + tslen,
1279 		    size, idx);
1280 		break;
1281 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1282 	case GOT_OBJ_TYPE_REF_DELTA:
1283 		err = open_delta_object(obj, packidx, pack, id, offset,
1284 		    tslen, type, size, idx);
1285 		break;
1286 	default:
1287 		err = got_error(GOT_ERR_OBJ_TYPE);
1288 		break;
1289 	}
1290 
1291 	return err;
1292 }
1293 
1294 const struct got_error *
1295 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1296     struct got_delta_chain *deltas, struct got_pack *pack)
1297 {
1298 	struct got_delta *delta;
1299 	uint64_t base_size = 0, result_size = 0;
1300 
1301 	*max_size = 0;
1302 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1303 		/* Plain object types are the delta base. */
1304 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1305 		    delta->type != GOT_OBJ_TYPE_TREE &&
1306 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1307 		    delta->type != GOT_OBJ_TYPE_TAG) {
1308 			const struct got_error *err;
1309 			uint8_t *delta_buf = NULL;
1310 			size_t delta_len;
1311 			int cached = 1;
1312 
1313 			if (pack->delta_cache) {
1314 				got_delta_cache_get(&delta_buf, &delta_len,
1315 				    NULL, NULL, pack->delta_cache,
1316 				    delta->data_offset);
1317 			}
1318 			if (delta_buf == NULL) {
1319 				cached = 0;
1320 				err = read_delta_data(&delta_buf, &delta_len,
1321 				    NULL, delta->data_offset, pack);
1322 				if (err)
1323 					return err;
1324 			}
1325 			if (pack->delta_cache && !cached) {
1326 				err = got_delta_cache_add(pack->delta_cache,
1327 				    delta->data_offset, delta_buf, delta_len);
1328 				if (err == NULL)
1329 					cached = 1;
1330 				else if (err->code != GOT_ERR_NO_SPACE) {
1331 					free(delta_buf);
1332 					return err;
1333 				}
1334 			}
1335 			err = got_delta_get_sizes(&base_size, &result_size,
1336 			    delta_buf, delta_len);
1337 			if (!cached)
1338 				free(delta_buf);
1339 			if (err)
1340 				return err;
1341 		} else
1342 			base_size = delta->size;
1343 		if (base_size > *max_size)
1344 			*max_size = base_size;
1345 		if (result_size > *max_size)
1346 			*max_size = result_size;
1347 	}
1348 
1349 	return NULL;
1350 }
1351 
1352 const struct got_error *
1353 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1354     struct got_pack *pack)
1355 {
1356 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1357 		return got_error(GOT_ERR_OBJ_TYPE);
1358 
1359 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1360 }
1361 
1362 const struct got_error *
1363 got_pack_dump_delta_chain_to_file(size_t *result_size,
1364     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1365     FILE *base_file, FILE *accum_file)
1366 {
1367 	const struct got_error *err = NULL;
1368 	struct got_delta *delta;
1369 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1370 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1371 	/* We process small enough files entirely in memory for speed. */
1372 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1373 	uint64_t max_size = 0;
1374 	int n = 0;
1375 
1376 	*result_size = 0;
1377 
1378 	if (STAILQ_EMPTY(&deltas->entries))
1379 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1380 
1381 	if (pack->delta_cache) {
1382 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1383 		size_t delta_len, fulltext_len;
1384 
1385 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1386 		got_delta_cache_get(&delta_buf, &delta_len,
1387 		    &fulltext, &fulltext_len,
1388 		    pack->delta_cache, delta->data_offset);
1389 		if (fulltext) {
1390 			size_t w;
1391 
1392 			w = fwrite(fulltext, 1, fulltext_len, outfile);
1393 			if (w != fulltext_len)
1394 				return got_ferror(outfile, GOT_ERR_IO);
1395 			if (fflush(outfile) != 0)
1396 				return got_error_from_errno("fflush");
1397 			*result_size = fulltext_len;
1398 			return NULL;
1399 		}
1400 	}
1401 
1402 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1403 		return got_error_from_errno("fseeko");
1404 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1405 		return got_error_from_errno("fseeko");
1406 
1407 	/* Deltas are ordered in ascending order. */
1408 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1409 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1410 		size_t delta_len, fulltext_len;
1411 		uint64_t base_size, result_size = 0;
1412 		int cached = 1;
1413 		if (n == 0) {
1414 			size_t mapoff;
1415 			off_t delta_data_offset;
1416 
1417 			/* Plain object types are the delta base. */
1418 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1419 			    delta->type != GOT_OBJ_TYPE_TREE &&
1420 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1421 			    delta->type != GOT_OBJ_TYPE_TAG) {
1422 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1423 				goto done;
1424 			}
1425 
1426 			delta_data_offset = delta->offset + delta->tslen;
1427 			if (delta_data_offset >= pack->filesize) {
1428 				err = got_error(GOT_ERR_PACK_OFFSET);
1429 				goto done;
1430 			}
1431 			if (pack->map == NULL) {
1432 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1433 				    == -1) {
1434 					err = got_error_from_errno("lseek");
1435 					goto done;
1436 				}
1437 			}
1438 			if (delta->size > max_size)
1439 				max_size = delta->size;
1440 			if (max_size > max_bufsize) {
1441 				if (pack->map) {
1442 					if (delta_data_offset > SIZE_MAX) {
1443 						return got_error_fmt(
1444 						    GOT_ERR_RANGE,
1445 						    "delta offset %lld "
1446 						    "overflows size_t",
1447 						    (long long)
1448 						    delta_data_offset);
1449 					}
1450 
1451 					mapoff = delta_data_offset;
1452 					err = got_inflate_to_file_mmap(
1453 					    &base_bufsz, NULL, NULL, pack->map,
1454 					    mapoff, pack->filesize - mapoff,
1455 					    base_file);
1456 				} else
1457 					err = got_inflate_to_file_fd(
1458 					    &base_bufsz, NULL, NULL, pack->fd,
1459 					    base_file);
1460 			} else {
1461 				accum_buf = malloc(max_size);
1462 				if (accum_buf == NULL) {
1463 					err = got_error_from_errno("malloc");
1464 					goto done;
1465 				}
1466 				accum_bufsz = max_size;
1467 				if (pack->map) {
1468 					if (delta_data_offset > SIZE_MAX) {
1469 						err = got_error_fmt(
1470 						    GOT_ERR_RANGE,
1471 						    "delta offset %lld "
1472 						    "overflows size_t",
1473 						    (long long)
1474 						    delta_data_offset);
1475 						goto done;
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 (err) {
1650 		free(accum_buf);
1651 		accum_buf = NULL;
1652 	}
1653 	if (accum_buf) {
1654 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1655 		free(accum_buf);
1656 		if (len != accum_size)
1657 			err = got_ferror(outfile, GOT_ERR_IO);
1658 	}
1659 	rewind(outfile);
1660 	if (err == NULL)
1661 		*result_size = accum_size;
1662 	return err;
1663 }
1664 
1665 const struct got_error *
1666 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1667     struct got_delta_chain *deltas, struct got_pack *pack)
1668 {
1669 	const struct got_error *err = NULL;
1670 	struct got_delta *delta;
1671 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1672 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1673 	uint64_t max_size = 0;
1674 	int n = 0;
1675 
1676 	*outbuf = NULL;
1677 	*outlen = 0;
1678 
1679 	if (STAILQ_EMPTY(&deltas->entries))
1680 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1681 
1682 	if (pack->delta_cache) {
1683 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1684 		size_t delta_len, fulltext_len;
1685 
1686 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1687 		got_delta_cache_get(&delta_buf, &delta_len,
1688 		    &fulltext, &fulltext_len,
1689 		    pack->delta_cache, delta->data_offset);
1690 		if (fulltext) {
1691 			*outbuf = malloc(fulltext_len);
1692 			if (*outbuf == NULL)
1693 				return got_error_from_errno("malloc");
1694 			memcpy(*outbuf, fulltext, fulltext_len);
1695 			*outlen = fulltext_len;
1696 			return NULL;
1697 		}
1698 	}
1699 
1700 	/* Deltas are ordered in ascending order. */
1701 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1702 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1703 		size_t delta_len, fulltext_len = 0;
1704 		uint64_t base_size, result_size = 0;
1705 		int cached = 1;
1706 		if (n == 0) {
1707 			off_t delta_data_offset;
1708 
1709 			/* Plain object types are the delta base. */
1710 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1711 			    delta->type != GOT_OBJ_TYPE_TREE &&
1712 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1713 			    delta->type != GOT_OBJ_TYPE_TAG) {
1714 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1715 				goto done;
1716 			}
1717 
1718 			delta_data_offset = delta->offset + delta->tslen;
1719 			if (delta_data_offset >= pack->filesize) {
1720 				err = got_error(GOT_ERR_PACK_OFFSET);
1721 				goto done;
1722 			}
1723 
1724 			if (pack->delta_cache) {
1725 				got_delta_cache_get(&delta_buf, &delta_len,
1726 				    &fulltext, &fulltext_len,
1727 				    pack->delta_cache, delta_data_offset);
1728 			}
1729 
1730 			if (delta->size > max_size)
1731 				max_size = delta->size;
1732 			if (delta->size > fulltext_len)
1733 				max_size = fulltext_len;
1734 
1735 			if (fulltext) {
1736 				base_buf = malloc(fulltext_len);
1737 				if (base_buf == NULL) {
1738 					err = got_error_from_errno("malloc");
1739 					goto done;
1740 				}
1741 				memcpy(base_buf, fulltext, fulltext_len);
1742 				base_bufsz = fulltext_len;
1743 			} else if (pack->map) {
1744 				size_t mapoff;
1745 
1746 				if (delta_data_offset > SIZE_MAX) {
1747 					return got_error_fmt(GOT_ERR_RANGE,
1748 					    "delta %lld offset would "
1749 					    "overflow size_t",
1750 					    (long long)delta_data_offset);
1751 				}
1752 
1753 				mapoff = delta_data_offset;
1754 				err = got_inflate_to_mem_mmap(&base_buf,
1755 				    &base_bufsz, NULL, NULL, pack->map,
1756 				    mapoff, pack->filesize - mapoff);
1757 			} else {
1758 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1759 				    == -1) {
1760 					err = got_error_from_errno("lseek");
1761 					goto done;
1762 				}
1763 				err = got_inflate_to_mem_fd(&base_buf,
1764 				    &base_bufsz, NULL, NULL, max_size,
1765 				    pack->fd);
1766 			}
1767 			if (err)
1768 				goto done;
1769 			n++;
1770 
1771 			if (pack->delta_cache && fulltext == NULL) {
1772 				err = got_delta_cache_add(pack->delta_cache,
1773 				    delta_data_offset, NULL, 0);
1774 				if (err) {
1775 					if (err->code != GOT_ERR_NO_SPACE)
1776 						goto done;
1777 					err = NULL;
1778 				} else {
1779 					err = got_delta_cache_add_fulltext(
1780 					    pack->delta_cache,
1781 					    delta_data_offset,
1782 					    base_buf, base_bufsz);
1783 					if (err &&
1784 					    err->code != GOT_ERR_NO_SPACE)
1785 						goto done;
1786 					err = NULL;
1787 				}
1788 			}
1789 			continue;
1790 		}
1791 
1792 		if (pack->delta_cache) {
1793 			got_delta_cache_get(&delta_buf, &delta_len,
1794 			    &fulltext, &fulltext_len,
1795 			    pack->delta_cache, delta->data_offset);
1796 		}
1797 		if (delta_buf == NULL) {
1798 			cached = 0;
1799 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1800 			    delta->data_offset, pack);
1801 			if (err)
1802 				goto done;
1803 		}
1804 		if (pack->delta_cache && !cached) {
1805 			err = got_delta_cache_add(pack->delta_cache,
1806 			    delta->data_offset, delta_buf, delta_len);
1807 			if (err == NULL)
1808 				cached = 1;
1809 			else if (err->code != GOT_ERR_NO_SPACE) {
1810 				free(delta_buf);
1811 				goto done;
1812 			}
1813 		}
1814 
1815 		err = got_delta_get_sizes(&base_size, &result_size,
1816 		    delta_buf, delta_len);
1817 		if (err) {
1818 			if (!cached)
1819 				free(delta_buf);
1820 			goto done;
1821 		}
1822 		if (base_size > max_size)
1823 			max_size = base_size;
1824 		if (result_size > max_size)
1825 			max_size = result_size;
1826 		if (fulltext_len > max_size)
1827 			max_size = fulltext_len;
1828 
1829 		if (max_size > base_bufsz) {
1830 			uint8_t *p = realloc(base_buf, max_size);
1831 			if (p == NULL) {
1832 				err = got_error_from_errno("realloc");
1833 				if (!cached)
1834 					free(delta_buf);
1835 				goto done;
1836 			}
1837 			base_buf = p;
1838 			base_bufsz = max_size;
1839 		}
1840 
1841 		if (max_size > accum_bufsz) {
1842 			uint8_t *p = realloc(accum_buf, max_size);
1843 			if (p == NULL) {
1844 				err = got_error_from_errno("realloc");
1845 				if (!cached)
1846 					free(delta_buf);
1847 				goto done;
1848 			}
1849 			accum_buf = p;
1850 			accum_bufsz = max_size;
1851 		}
1852 
1853 		if (fulltext) {
1854 			memcpy(accum_buf, fulltext, fulltext_len);
1855 			accum_size = fulltext_len;
1856 			err = NULL;
1857 		} else {
1858 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1859 			    delta_buf, delta_len, accum_buf,
1860 			    &accum_size, max_size);
1861 		}
1862 		if (!cached)
1863 			free(delta_buf);
1864 		n++;
1865 		if (err)
1866 			goto done;
1867 
1868 		if (fulltext == NULL) {
1869 			err = got_delta_cache_add_fulltext(pack->delta_cache,
1870 			    delta->data_offset, accum_buf, accum_size);
1871 			if (err) {
1872 				if (err->code != GOT_ERR_NO_SPACE)
1873 					goto done;
1874 				err = NULL;
1875 			}
1876 		}
1877 
1878 		if (n < deltas->nentries) {
1879 			/* Accumulated delta becomes the new base. */
1880 			uint8_t *tmp = accum_buf;
1881 			size_t tmp_size = accum_bufsz;
1882 			accum_buf = base_buf;
1883 			accum_bufsz = base_bufsz;
1884 			base_buf = tmp;
1885 			base_bufsz = tmp_size;
1886 		}
1887 	}
1888 
1889 done:
1890 	free(base_buf);
1891 	if (err) {
1892 		free(accum_buf);
1893 		*outbuf = NULL;
1894 		*outlen = 0;
1895 	} else {
1896 		*outbuf = accum_buf;
1897 		*outlen = accum_size;
1898 	}
1899 	return err;
1900 }
1901 
1902 const struct got_error *
1903 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1904     FILE *outfile, FILE *base_file, FILE *accum_file)
1905 {
1906 	const struct got_error *err = NULL;
1907 
1908 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1909 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1910 
1911 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1912 		if (obj->pack_offset >= pack->filesize)
1913 			return got_error(GOT_ERR_PACK_OFFSET);
1914 
1915 		if (pack->map) {
1916 			size_t mapoff;
1917 
1918 			if (obj->pack_offset > SIZE_MAX) {
1919 				return got_error_fmt(GOT_ERR_RANGE,
1920 				    "pack offset %lld would overflow size_t",
1921 				    (long long)obj->pack_offset);
1922 			}
1923 
1924 			mapoff = obj->pack_offset;
1925 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1926 			    pack->map, mapoff, pack->filesize - mapoff,
1927 			    outfile);
1928 		} else {
1929 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1930 				return got_error_from_errno("lseek");
1931 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1932 			    pack->fd, outfile);
1933 		}
1934 	} else
1935 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1936 		    &obj->deltas, pack, outfile, base_file, accum_file);
1937 
1938 	return err;
1939 }
1940 
1941 const struct got_error *
1942 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1943     struct got_object *obj, struct got_pack *pack)
1944 {
1945 	const struct got_error *err = NULL;
1946 
1947 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1948 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1949 
1950 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1951 		if (obj->pack_offset >= pack->filesize)
1952 			return got_error(GOT_ERR_PACK_OFFSET);
1953 		if (pack->map) {
1954 			size_t mapoff;
1955 
1956 			if (obj->pack_offset > SIZE_MAX) {
1957 				return got_error_fmt(GOT_ERR_RANGE,
1958 				    "pack offset %lld would overflow size_t",
1959 				    (long long)obj->pack_offset);
1960 			}
1961 
1962 			mapoff = obj->pack_offset;
1963 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1964 			    pack->map, mapoff, pack->filesize - mapoff);
1965 		} else {
1966 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1967 				return got_error_from_errno("lseek");
1968 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1969 			    obj->size, pack->fd);
1970 		}
1971 	} else
1972 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1973 		    pack);
1974 
1975 	return err;
1976 }
1977 
1978 static const struct got_error *
1979 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1980     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1981     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1982 {
1983 	const struct got_error *err = NULL;
1984 
1985 	/* Validate decompression and obtain the decompressed size. */
1986 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1987 	    delta_data_offset, pack);
1988 	if (err)
1989 		return err;
1990 
1991 	/* Read delta base/result sizes from head of delta stream. */
1992 	err = got_delta_get_sizes(base_size, result_size,
1993 	    *delta_buf, *delta_len);
1994 	if (err)
1995 		goto done;
1996 
1997 	/* Discard decompressed delta and read it again in compressed form. */
1998 	free(*delta_buf);
1999 	*delta_buf = malloc(*delta_len_compressed);
2000 	if (*delta_buf == NULL) {
2001 		err = got_error_from_errno("malloc");
2002 		goto done;
2003 	}
2004 	if (pack->map) {
2005 		if (delta_data_offset >= pack->filesize) {
2006 			err = got_error(GOT_ERR_PACK_OFFSET);
2007 			goto done;
2008 		}
2009 		memcpy(*delta_buf, pack->map + delta_data_offset,
2010 		    *delta_len_compressed);
2011 	} else {
2012 		ssize_t n;
2013 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
2014 			err = got_error_from_errno("lseek");
2015 			goto done;
2016 		}
2017 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
2018 		if (n < 0) {
2019 			err = got_error_from_errno("read");
2020 			goto done;
2021 		} else if (n != *delta_len_compressed) {
2022 			err = got_error(GOT_ERR_IO);
2023 			goto done;
2024 		}
2025 	}
2026 done:
2027 	if (err) {
2028 		free(*delta_buf);
2029 		*delta_buf = NULL;
2030 		*delta_len = 0;
2031 		*delta_len_compressed = 0;
2032 		*base_size = 0;
2033 		*result_size = 0;
2034 	}
2035 	return err;
2036 }
2037 
2038 const struct got_error *
2039 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
2040     size_t *delta_compressed_size, off_t *delta_offset,
2041     off_t *delta_data_offset, off_t *base_offset,
2042     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
2043     struct got_pack *pack, struct got_packidx *packidx, int idx)
2044 {
2045 	const struct got_error *err = NULL;
2046 	off_t offset;
2047 	uint8_t type;
2048 	uint64_t size;
2049 	size_t tslen, delta_hdrlen;
2050 
2051 	*delta_buf = NULL;
2052 	*delta_size = 0;
2053 	*delta_compressed_size = 0;
2054 	*delta_offset = 0;
2055 	*delta_data_offset = 0;
2056 	*base_offset = 0;
2057 	*base_size = 0;
2058 	*result_size = 0;
2059 
2060 	offset = got_packidx_get_object_offset(packidx, idx);
2061 	if (offset == -1)
2062 		return got_error(GOT_ERR_BAD_PACKIDX);
2063 
2064 	if (offset >= pack->filesize)
2065 		return got_error(GOT_ERR_PACK_OFFSET);
2066 
2067 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
2068 	    pack, offset);
2069 	if (err)
2070 		return err;
2071 
2072 	if (tslen + size < tslen || offset + size < size ||
2073 	    tslen + offset < tslen)
2074 		return got_error(GOT_ERR_PACK_OFFSET);
2075 
2076 	switch (type) {
2077 	case GOT_OBJ_TYPE_OFFSET_DELTA:
2078 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
2079 		    pack, offset, tslen);
2080 		if (err)
2081 			return err;
2082 		break;
2083 	case GOT_OBJ_TYPE_REF_DELTA:
2084 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
2085 		if (err)
2086 			return err;
2087 		delta_hdrlen = SHA1_DIGEST_LENGTH;
2088 		break;
2089 	default:
2090 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
2091 		    "non-delta object type %d found at offset %lld",
2092 		    type, (long long)offset);
2093 	}
2094 
2095 	if (tslen + delta_hdrlen < delta_hdrlen ||
2096 	    offset + delta_hdrlen < delta_hdrlen)
2097 		return got_error(GOT_ERR_BAD_DELTA);
2098 
2099 	*delta_data_offset = offset + tslen + delta_hdrlen;
2100 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
2101 	    base_size, result_size, *delta_data_offset, pack, packidx);
2102 	if (err)
2103 		return err;
2104 
2105 	if (*delta_size != size) {
2106 		err = got_error(GOT_ERR_BAD_DELTA);
2107 		goto done;
2108 	}
2109 
2110 	*delta_offset = offset;
2111 done:
2112 	if (err) {
2113 		free(*delta_buf);
2114 		*delta_buf = NULL;
2115 		*delta_size = 0;
2116 		*delta_compressed_size = 0;
2117 		*delta_offset = 0;
2118 		*base_offset = 0;
2119 		*base_size = 0;
2120 		*result_size = 0;
2121 	}
2122 	return err;
2123 }