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 	if (prefix_len < 2)
676 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
677 
678 	hex[0] = id_str_prefix[0];
679 	hex[1] = id_str_prefix[1];
680 	hex[2] = '\0';
681 	if (!got_parse_xdigit(&id0, hex))
682 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
683 
684 	if (id0 > 0)
685 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
686 	oid = &packidx->hdr.sorted_ids[i];
687 	while (i < totobj && oid->sha1[0] == id0) {
688 		char id_str[SHA1_DIGEST_STRING_LENGTH];
689 		struct got_object_qid *qid;
690 		int cmp;
691 
692 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
693 			return got_error(GOT_ERR_NO_SPACE);
694 
695 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
696 		if (cmp < 0) {
697 			oid = &packidx->hdr.sorted_ids[++i];
698 			continue;
699 		} else if (cmp > 0)
700 			break;
701 
702 		err = got_object_qid_alloc_partial(&qid);
703 		if (err)
704 			return err;
705 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
706 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
707 
708 		oid = &packidx->hdr.sorted_ids[++i];
709 	}
710 
711 	return NULL;
712 }
713 
714 static void
715 set_max_datasize(void)
716 {
717 	struct rlimit rl;
718 
719 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
720 		return;
721 
722 	rl.rlim_cur = rl.rlim_max;
723 	setrlimit(RLIMIT_DATA, &rl);
724 }
725 
726 const struct got_error *
727 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
728 {
729 	const struct got_error *err = NULL;
730 	int imsg_fds[2];
731 	pid_t pid;
732 	struct imsgbuf *ibuf;
733 
734 	ibuf = calloc(1, sizeof(*ibuf));
735 	if (ibuf == NULL)
736 		return got_error_from_errno("calloc");
737 
738 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
739 	if (pack->privsep_child == NULL) {
740 		err = got_error_from_errno("calloc");
741 		free(ibuf);
742 		return err;
743 	}
744 	pack->child_has_tempfiles = 0;
745 	pack->child_has_delta_outfd = 0;
746 
747 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
748 		err = got_error_from_errno("socketpair");
749 		goto done;
750 	}
751 
752 	pid = fork();
753 	if (pid == -1) {
754 		err = got_error_from_errno("fork");
755 		goto done;
756 	} else if (pid == 0) {
757 		set_max_datasize();
758 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
759 		    pack->path_packfile);
760 		/* not reached */
761 	}
762 
763 	if (close(imsg_fds[1]) == -1)
764 		return got_error_from_errno("close");
765 	pack->privsep_child->imsg_fd = imsg_fds[0];
766 	pack->privsep_child->pid = pid;
767 	imsg_init(ibuf, imsg_fds[0]);
768 	pack->privsep_child->ibuf = ibuf;
769 
770 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
771 	if (err) {
772 		const struct got_error *child_err;
773 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
774 		child_err = got_privsep_wait_for_child(
775 		    pack->privsep_child->pid);
776 		if (child_err && err == NULL)
777 			err = child_err;
778 	}
779 done:
780 	if (err) {
781 		free(ibuf);
782 		free(pack->privsep_child);
783 		pack->privsep_child = NULL;
784 	}
785 	return err;
786 }
787 
788 static const struct got_error *
789 pack_stop_privsep_child(struct got_pack *pack)
790 {
791 	const struct got_error *err = NULL, *close_err = NULL;
792 
793 	if (pack->privsep_child == NULL)
794 		return NULL;
795 
796 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
797 	if (err)
798 		return err;
799 	if (close(pack->privsep_child->imsg_fd) == -1)
800 		close_err = got_error_from_errno("close");
801 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
802 	if (close_err && err == NULL)
803 		err = close_err;
804 	imsg_clear(pack->privsep_child->ibuf);
805 	free(pack->privsep_child->ibuf);
806 	free(pack->privsep_child);
807 	pack->privsep_child = NULL;
808 	return err;
809 }
810 
811 const struct got_error *
812 got_pack_close(struct got_pack *pack)
813 {
814 	const struct got_error *err = NULL;
815 
816 	err = pack_stop_privsep_child(pack);
817 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
818 		err = got_error_from_errno("munmap");
819 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
820 		err = got_error_from_errno("close");
821 	pack->fd = -1;
822 	free(pack->path_packfile);
823 	pack->path_packfile = NULL;
824 	pack->filesize = 0;
825 	if (pack->delta_cache) {
826 		got_delta_cache_free(pack->delta_cache);
827 		pack->delta_cache = NULL;
828 	}
829 
830 	/*
831 	 * Leave accumfd and basefd alone. They are managed by the
832 	 * repository layer and can be reused.
833 	 */
834 
835 	return err;
836 }
837 
838 const struct got_error *
839 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
840     struct got_pack *pack, off_t offset)
841 {
842 	uint8_t t = 0;
843 	uint64_t s = 0;
844 	uint8_t sizeN;
845 	size_t mapoff = 0;
846 	int i = 0;
847 
848 	*len = 0;
849 
850 	if (offset >= pack->filesize)
851 		return got_error(GOT_ERR_PACK_OFFSET);
852 
853 	if (pack->map) {
854 		if (offset > SIZE_MAX) {
855 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
856 			    "offset %lld overflows size_t",
857 			    (long long)offset);
858 		}
859 
860 		mapoff = (size_t)offset;
861 	} else {
862 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
863 			return got_error_from_errno("lseek");
864 	}
865 
866 	do {
867 		/* We do not support size values which don't fit in 64 bit. */
868 		if (i > 9)
869 			return got_error_fmt(GOT_ERR_OBJ_TOO_LARGE,
870 			    "packfile offset %lld", (long long)offset);
871 
872 		if (pack->map) {
873 			if (mapoff + sizeof(sizeN) >= pack->filesize)
874 				return got_error(GOT_ERR_BAD_PACKFILE);
875 			sizeN = *(pack->map + mapoff);
876 			mapoff += sizeof(sizeN);
877 		} else {
878 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
879 			if (n < 0)
880 				return got_error_from_errno("read");
881 			if (n != sizeof(sizeN))
882 				return got_error(GOT_ERR_BAD_PACKFILE);
883 		}
884 		*len += sizeof(sizeN);
885 
886 		if (i == 0) {
887 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
888 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
889 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
890 		} else {
891 			size_t shift = 4 + 7 * (i - 1);
892 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
893 		}
894 		i++;
895 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
896 
897 	*type = t;
898 	*size = s;
899 	return NULL;
900 }
901 
902 static const struct got_error *
903 open_plain_object(struct got_object **obj, struct got_object_id *id,
904     uint8_t type, off_t offset, size_t size, int idx)
905 {
906 	*obj = calloc(1, sizeof(**obj));
907 	if (*obj == NULL)
908 		return got_error_from_errno("calloc");
909 
910 	(*obj)->type = type;
911 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
912 	(*obj)->pack_idx = idx;
913 	(*obj)->hdrlen = 0;
914 	(*obj)->size = size;
915 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
916 	(*obj)->pack_offset = offset;
917 
918 	return NULL;
919 }
920 
921 static const struct got_error *
922 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
923     off_t delta_offset)
924 {
925 	int64_t o = 0;
926 	uint8_t offN;
927 	int i = 0;
928 
929 	*offset = 0;
930 	*len = 0;
931 
932 	do {
933 		/* We do not support offset values which don't fit in 64 bit. */
934 		if (i > 8)
935 			return got_error(GOT_ERR_NO_SPACE);
936 
937 		if (pack->map) {
938 			size_t mapoff;
939 
940 			if (delta_offset + *len > SIZE_MAX) {
941 				return got_error_fmt(GOT_ERR_PACK_OFFSET,
942 				    "mapoff %lld would overflow size_t",
943 				    (long long)delta_offset + *len);
944 			}
945 
946 			mapoff = (size_t)delta_offset + *len;
947 			if (mapoff + sizeof(offN) >= pack->filesize)
948 				return got_error(GOT_ERR_PACK_OFFSET);
949 			offN = *(pack->map + mapoff);
950 		} else {
951 			ssize_t n;
952 			n = read(pack->fd, &offN, sizeof(offN));
953 			if (n < 0)
954 				return got_error_from_errno("read");
955 			if (n != sizeof(offN))
956 				return got_error(GOT_ERR_BAD_PACKFILE);
957 		}
958 		*len += sizeof(offN);
959 
960 		if (i == 0)
961 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
962 		else {
963 			o++;
964 			o <<= 7;
965 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
966 		}
967 		i++;
968 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
969 
970 	*offset = o;
971 	return NULL;
972 }
973 
974 const struct got_error *
975 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
976     struct got_pack *pack, off_t offset, size_t tslen)
977 {
978 	const struct got_error *err;
979 	int64_t negoffset;
980 	size_t negofflen;
981 
982 	*len = 0;
983 
984 	err = parse_negative_offset(&negoffset, &negofflen, pack,
985 	    offset + tslen);
986 	if (err)
987 		return err;
988 
989 	/* Compute the base object's offset (must be in the same pack file). */
990 	*base_offset = (offset - negoffset);
991 	if (*base_offset <= 0)
992 		return got_error(GOT_ERR_BAD_PACKFILE);
993 
994 	*len = negofflen;
995 	return NULL;
996 }
997 
998 static const struct got_error *
999 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
1000     size_t *delta_compressed_len, size_t delta_data_offset,
1001     struct got_pack *pack)
1002 {
1003 	const struct got_error *err = NULL;
1004 	size_t consumed = 0;
1005 
1006 	if (pack->map) {
1007 		if (delta_data_offset >= pack->filesize)
1008 			return got_error(GOT_ERR_PACK_OFFSET);
1009 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
1010 		    &consumed, NULL, pack->map, delta_data_offset,
1011 		    pack->filesize - delta_data_offset);
1012 		if (err)
1013 			return err;
1014 	} else {
1015 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
1016 			return got_error_from_errno("lseek");
1017 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1018 		    &consumed, NULL, 0, pack->fd);
1019 		if (err)
1020 			return err;
1021 	}
1022 
1023 	if (delta_compressed_len)
1024 		*delta_compressed_len = consumed;
1025 
1026 	return NULL;
1027 }
1028 
1029 static const struct got_error *
1030 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1031     int delta_type, size_t delta_size, off_t delta_data_offset)
1032 {
1033 	struct got_delta *delta;
1034 
1035 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1036 	    delta_data_offset);
1037 	if (delta == NULL)
1038 		return got_error_from_errno("got_delta_open");
1039 	/* delta is freed in got_object_close() */
1040 	deltas->nentries++;
1041 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1042 	return NULL;
1043 }
1044 
1045 static const struct got_error *
1046 resolve_offset_delta(struct got_delta_chain *deltas,
1047     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1048     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1049 {
1050 	const struct got_error *err;
1051 	off_t base_offset;
1052 	uint8_t base_type;
1053 	uint64_t base_size;
1054 	size_t base_tslen;
1055 	off_t delta_data_offset;
1056 	size_t consumed;
1057 
1058 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1059 	    delta_offset, tslen);
1060 	if (err)
1061 		return err;
1062 
1063 	delta_data_offset = delta_offset + tslen + consumed;
1064 	if (delta_data_offset >= pack->filesize)
1065 		return got_error(GOT_ERR_PACK_OFFSET);
1066 
1067 	if (pack->map == NULL) {
1068 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1069 		if (delta_data_offset == -1)
1070 			return got_error_from_errno("lseek");
1071 	}
1072 
1073 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1074 	    delta_data_offset);
1075 	if (err)
1076 		return err;
1077 
1078 	/* An offset delta must be in the same packfile. */
1079 	if (base_offset >= pack->filesize)
1080 		return got_error(GOT_ERR_PACK_OFFSET);
1081 
1082 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1083 	    &base_tslen, pack, base_offset);
1084 	if (err)
1085 		return err;
1086 
1087 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1088 	    base_tslen, base_type, base_size, recursion - 1);
1089 }
1090 
1091 const struct got_error *
1092 got_pack_parse_ref_delta(struct got_object_id *id,
1093     struct got_pack *pack, off_t delta_offset, int tslen)
1094 {
1095 	if (pack->map) {
1096 		size_t mapoff;
1097 
1098 		if (delta_offset + tslen > SIZE_MAX) {
1099 			return got_error_fmt(GOT_ERR_PACK_OFFSET,
1100 			    "mapoff %lld would overflow size_t",
1101 			    (long long)delta_offset + tslen);
1102 		}
1103 
1104 		mapoff = delta_offset + tslen;
1105 		if (mapoff + sizeof(*id) >= pack->filesize)
1106 			return got_error(GOT_ERR_PACK_OFFSET);
1107 		memcpy(id, pack->map + mapoff, sizeof(*id));
1108 	} else {
1109 		ssize_t n;
1110 		n = read(pack->fd, id, sizeof(*id));
1111 		if (n < 0)
1112 			return got_error_from_errno("read");
1113 		if (n != sizeof(*id))
1114 			return got_error(GOT_ERR_BAD_PACKFILE);
1115 	}
1116 
1117 	return NULL;
1118 }
1119 
1120 static const struct got_error *
1121 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1122     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1123     size_t delta_size, unsigned int recursion)
1124 {
1125 	const struct got_error *err;
1126 	struct got_object_id id;
1127 	int idx;
1128 	off_t base_offset;
1129 	uint8_t base_type;
1130 	uint64_t base_size;
1131 	size_t base_tslen;
1132 	off_t delta_data_offset;
1133 
1134 	if (delta_offset + tslen >= pack->filesize)
1135 		return got_error(GOT_ERR_PACK_OFFSET);
1136 
1137 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1138 	if (err)
1139 		return err;
1140 	if (pack->map) {
1141 		delta_data_offset = delta_offset + tslen + SHA1_DIGEST_LENGTH;
1142 	} else {
1143 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1144 		if (delta_data_offset == -1)
1145 			return got_error_from_errno("lseek");
1146 	}
1147 
1148 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1149 	    delta_data_offset);
1150 	if (err)
1151 		return err;
1152 
1153 	/* Delta base must be in the same pack file. */
1154 	idx = got_packidx_get_object_idx(packidx, &id);
1155 	if (idx == -1)
1156 		return got_error(GOT_ERR_NO_OBJ);
1157 
1158 	base_offset = got_packidx_get_object_offset(packidx, idx);
1159 	if (base_offset == -1)
1160 		return got_error(GOT_ERR_BAD_PACKIDX);
1161 
1162 	if (base_offset >= pack->filesize)
1163 		return got_error(GOT_ERR_PACK_OFFSET);
1164 
1165 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1166 	    &base_tslen, pack, base_offset);
1167 	if (err)
1168 		return err;
1169 
1170 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1171 	    base_tslen, base_type, base_size, recursion - 1);
1172 }
1173 
1174 const struct got_error *
1175 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1176     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1177     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1178 {
1179 	const struct got_error *err = NULL;
1180 
1181 	if (--recursion == 0)
1182 		return got_error(GOT_ERR_RECURSION);
1183 
1184 	switch (delta_type) {
1185 	case GOT_OBJ_TYPE_COMMIT:
1186 	case GOT_OBJ_TYPE_TREE:
1187 	case GOT_OBJ_TYPE_BLOB:
1188 	case GOT_OBJ_TYPE_TAG:
1189 		/* Plain types are the final delta base. Recursion ends. */
1190 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1191 		    delta_size, 0);
1192 		break;
1193 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1194 		err = resolve_offset_delta(deltas, packidx, pack,
1195 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1196 		break;
1197 	case GOT_OBJ_TYPE_REF_DELTA:
1198 		err = resolve_ref_delta(deltas, packidx, pack,
1199 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1200 		break;
1201 	default:
1202 		return got_error(GOT_ERR_OBJ_TYPE);
1203 	}
1204 
1205 	return err;
1206 }
1207 
1208 static const struct got_error *
1209 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1210     struct got_pack *pack, struct got_object_id *id, off_t offset,
1211     size_t tslen, int delta_type, size_t delta_size, int idx)
1212 {
1213 	const struct got_error *err = NULL;
1214 	int resolved_type;
1215 
1216 	*obj = calloc(1, sizeof(**obj));
1217 	if (*obj == NULL)
1218 		return got_error_from_errno("calloc");
1219 
1220 	(*obj)->flags = 0;
1221 	(*obj)->hdrlen = 0;
1222 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1223 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1224 	(*obj)->pack_offset = offset + tslen;
1225 
1226 	STAILQ_INIT(&(*obj)->deltas.entries);
1227 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1228 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1229 	(*obj)->pack_idx = idx;
1230 
1231 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1232 	    offset, tslen, delta_type, delta_size,
1233 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1234 	if (err)
1235 		goto done;
1236 
1237 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1238 	if (err)
1239 		goto done;
1240 	(*obj)->type = resolved_type;
1241 done:
1242 	if (err) {
1243 		got_object_close(*obj);
1244 		*obj = NULL;
1245 	}
1246 	return err;
1247 }
1248 
1249 const struct got_error *
1250 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1251     struct got_packidx *packidx, int idx, struct got_object_id *id)
1252 {
1253 	const struct got_error *err = NULL;
1254 	off_t offset;
1255 	uint8_t type;
1256 	uint64_t size;
1257 	size_t tslen;
1258 
1259 	*obj = NULL;
1260 
1261 	offset = got_packidx_get_object_offset(packidx, idx);
1262 	if (offset == -1)
1263 		return got_error(GOT_ERR_BAD_PACKIDX);
1264 
1265 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1266 	    pack, offset);
1267 	if (err)
1268 		return err;
1269 
1270 	switch (type) {
1271 	case GOT_OBJ_TYPE_COMMIT:
1272 	case GOT_OBJ_TYPE_TREE:
1273 	case GOT_OBJ_TYPE_BLOB:
1274 	case GOT_OBJ_TYPE_TAG:
1275 		err = open_plain_object(obj, id, type, offset + tslen,
1276 		    size, idx);
1277 		break;
1278 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1279 	case GOT_OBJ_TYPE_REF_DELTA:
1280 		err = open_delta_object(obj, packidx, pack, id, offset,
1281 		    tslen, type, size, idx);
1282 		break;
1283 	default:
1284 		err = got_error(GOT_ERR_OBJ_TYPE);
1285 		break;
1286 	}
1287 
1288 	return err;
1289 }
1290 
1291 const struct got_error *
1292 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1293     struct got_delta_chain *deltas, struct got_pack *pack)
1294 {
1295 	struct got_delta *delta;
1296 	uint64_t base_size = 0, result_size = 0;
1297 
1298 	*max_size = 0;
1299 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1300 		/* Plain object types are the delta base. */
1301 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1302 		    delta->type != GOT_OBJ_TYPE_TREE &&
1303 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1304 		    delta->type != GOT_OBJ_TYPE_TAG) {
1305 			const struct got_error *err;
1306 			uint8_t *delta_buf = NULL;
1307 			size_t delta_len;
1308 			int cached = 1;
1309 
1310 			if (pack->delta_cache) {
1311 				got_delta_cache_get(&delta_buf, &delta_len,
1312 				    NULL, NULL, pack->delta_cache,
1313 				    delta->data_offset);
1314 			}
1315 			if (delta_buf == NULL) {
1316 				cached = 0;
1317 				err = read_delta_data(&delta_buf, &delta_len,
1318 				    NULL, delta->data_offset, pack);
1319 				if (err)
1320 					return err;
1321 			}
1322 			if (pack->delta_cache && !cached) {
1323 				err = got_delta_cache_add(pack->delta_cache,
1324 				    delta->data_offset, delta_buf, delta_len);
1325 				if (err == NULL)
1326 					cached = 1;
1327 				else if (err->code != GOT_ERR_NO_SPACE) {
1328 					free(delta_buf);
1329 					return err;
1330 				}
1331 			}
1332 			err = got_delta_get_sizes(&base_size, &result_size,
1333 			    delta_buf, delta_len);
1334 			if (!cached)
1335 				free(delta_buf);
1336 			if (err)
1337 				return err;
1338 		} else
1339 			base_size = delta->size;
1340 		if (base_size > *max_size)
1341 			*max_size = base_size;
1342 		if (result_size > *max_size)
1343 			*max_size = result_size;
1344 	}
1345 
1346 	return NULL;
1347 }
1348 
1349 const struct got_error *
1350 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1351     struct got_pack *pack)
1352 {
1353 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1354 		return got_error(GOT_ERR_OBJ_TYPE);
1355 
1356 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1357 }
1358 
1359 const struct got_error *
1360 got_pack_dump_delta_chain_to_file(size_t *result_size,
1361     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1362     FILE *base_file, FILE *accum_file)
1363 {
1364 	const struct got_error *err = NULL;
1365 	struct got_delta *delta;
1366 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1367 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1368 	/* We process small enough files entirely in memory for speed. */
1369 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1370 	uint64_t max_size = 0;
1371 	int n = 0;
1372 
1373 	*result_size = 0;
1374 
1375 	if (STAILQ_EMPTY(&deltas->entries))
1376 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1377 
1378 	if (pack->delta_cache) {
1379 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1380 		size_t delta_len, fulltext_len;
1381 
1382 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1383 		got_delta_cache_get(&delta_buf, &delta_len,
1384 		    &fulltext, &fulltext_len,
1385 		    pack->delta_cache, delta->data_offset);
1386 		if (fulltext) {
1387 			size_t w;
1388 
1389 			w = fwrite(fulltext, 1, fulltext_len, outfile);
1390 			if (w != fulltext_len)
1391 				return got_ferror(outfile, GOT_ERR_IO);
1392 			if (fflush(outfile) != 0)
1393 				return got_error_from_errno("fflush");
1394 			*result_size = fulltext_len;
1395 			return NULL;
1396 		}
1397 	}
1398 
1399 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1400 		return got_error_from_errno("fseeko");
1401 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1402 		return got_error_from_errno("fseeko");
1403 
1404 	/* Deltas are ordered in ascending order. */
1405 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1406 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1407 		size_t delta_len, fulltext_len;
1408 		uint64_t base_size, result_size = 0;
1409 		int cached = 1;
1410 		if (n == 0) {
1411 			size_t mapoff;
1412 			off_t delta_data_offset;
1413 
1414 			/* Plain object types are the delta base. */
1415 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1416 			    delta->type != GOT_OBJ_TYPE_TREE &&
1417 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1418 			    delta->type != GOT_OBJ_TYPE_TAG) {
1419 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1420 				goto done;
1421 			}
1422 
1423 			delta_data_offset = delta->offset + delta->tslen;
1424 			if (delta_data_offset >= pack->filesize) {
1425 				err = got_error(GOT_ERR_PACK_OFFSET);
1426 				goto done;
1427 			}
1428 			if (pack->map == NULL) {
1429 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1430 				    == -1) {
1431 					err = got_error_from_errno("lseek");
1432 					goto done;
1433 				}
1434 			}
1435 			if (delta->size > max_size)
1436 				max_size = delta->size;
1437 			if (max_size > max_bufsize) {
1438 				if (pack->map) {
1439 					if (delta_data_offset > SIZE_MAX) {
1440 						return got_error_fmt(
1441 						    GOT_ERR_RANGE,
1442 						    "delta offset %lld "
1443 						    "overflows size_t",
1444 						    (long long)
1445 						    delta_data_offset);
1446 					}
1447 
1448 					mapoff = delta_data_offset;
1449 					err = got_inflate_to_file_mmap(
1450 					    &base_bufsz, NULL, NULL, pack->map,
1451 					    mapoff, pack->filesize - mapoff,
1452 					    base_file);
1453 				} else
1454 					err = got_inflate_to_file_fd(
1455 					    &base_bufsz, NULL, NULL, pack->fd,
1456 					    base_file);
1457 			} else {
1458 				accum_buf = malloc(max_size);
1459 				if (accum_buf == NULL) {
1460 					err = got_error_from_errno("malloc");
1461 					goto done;
1462 				}
1463 				accum_bufsz = max_size;
1464 				if (pack->map) {
1465 					if (delta_data_offset > SIZE_MAX) {
1466 						err = got_error_fmt(
1467 						    GOT_ERR_RANGE,
1468 						    "delta offset %lld "
1469 						    "overflows size_t",
1470 						    (long long)
1471 						    delta_data_offset);
1472 						goto done;
1473 					}
1474 
1475 					mapoff = delta_data_offset;
1476 					err = got_inflate_to_mem_mmap(&base_buf,
1477 					    &base_bufsz, NULL, NULL,
1478 					    pack->map, mapoff,
1479 					    pack->filesize - mapoff);
1480 				} else
1481 					err = got_inflate_to_mem_fd(&base_buf,
1482 					    &base_bufsz, NULL, NULL, max_size,
1483 					    pack->fd);
1484 			}
1485 			if (err)
1486 				goto done;
1487 			n++;
1488 			if (base_buf == NULL)
1489 				rewind(base_file);
1490 			else if (pack->delta_cache && fulltext == NULL) {
1491 				err = got_delta_cache_add(pack->delta_cache,
1492 				    delta_data_offset, NULL, 0);
1493 				if (err) {
1494 					if (err->code != GOT_ERR_NO_SPACE)
1495 						goto done;
1496 					err = NULL;
1497 				} else {
1498 					err = got_delta_cache_add_fulltext(
1499 					    pack->delta_cache,
1500 					    delta_data_offset,
1501 					    base_buf, base_bufsz);
1502 					if (err &&
1503 					    err->code != GOT_ERR_NO_SPACE)
1504 						goto done;
1505 					err = NULL;
1506 				}
1507 			}
1508 			continue;
1509 		}
1510 
1511 		if (pack->delta_cache) {
1512 			got_delta_cache_get(&delta_buf, &delta_len,
1513 			    &fulltext, &fulltext_len,
1514 			    pack->delta_cache, delta->data_offset);
1515 		}
1516 		if (delta_buf == NULL) {
1517 			cached = 0;
1518 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1519 			    delta->data_offset, pack);
1520 			if (err)
1521 				goto done;
1522 		}
1523 		if (pack->delta_cache && !cached) {
1524 			err = got_delta_cache_add(pack->delta_cache,
1525 			    delta->data_offset, delta_buf, delta_len);
1526 			if (err == NULL)
1527 				cached = 1;
1528 			else if (err->code != GOT_ERR_NO_SPACE) {
1529 				free(delta_buf);
1530 				goto done;
1531 			}
1532 		}
1533 
1534 		err = got_delta_get_sizes(&base_size, &result_size,
1535 		    delta_buf, delta_len);
1536 		if (err) {
1537 			if (!cached)
1538 				free(delta_buf);
1539 			goto done;
1540 		}
1541 		if (base_size > max_size)
1542 			max_size = base_size;
1543 		if (result_size > max_size)
1544 			max_size = result_size;
1545 		if (fulltext_len > max_size)
1546 			max_size = fulltext_len;
1547 
1548 		if (base_buf && max_size > max_bufsize) {
1549 			/* Switch from buffers to temporary files. */
1550 			size_t w = fwrite(base_buf, 1, base_bufsz,
1551 			    base_file);
1552 			if (w != base_bufsz) {
1553 				err = got_ferror(outfile, GOT_ERR_IO);
1554 				if (!cached)
1555 					free(delta_buf);
1556 				goto done;
1557 			}
1558 			free(base_buf);
1559 			base_buf = NULL;
1560 			free(accum_buf);
1561 			accum_buf = NULL;
1562 		}
1563 
1564 		if (base_buf && max_size > base_bufsz) {
1565 			uint8_t *p = realloc(base_buf, max_size);
1566 			if (p == NULL) {
1567 				err = got_error_from_errno("realloc");
1568 				if (!cached)
1569 					free(delta_buf);
1570 				goto done;
1571 			}
1572 			base_buf = p;
1573 			base_bufsz = max_size;
1574 		}
1575 
1576 		if (accum_buf && max_size > accum_bufsz) {
1577 			uint8_t *p = realloc(accum_buf, max_size);
1578 			if (p == NULL) {
1579 				err = got_error_from_errno("realloc");
1580 				if (!cached)
1581 					free(delta_buf);
1582 				goto done;
1583 			}
1584 			accum_buf = p;
1585 			accum_bufsz = max_size;
1586 		}
1587 
1588 		if (base_buf) {
1589 			if (fulltext) {
1590 				memcpy(accum_buf, fulltext, fulltext_len);
1591 				accum_size = fulltext_len;
1592 				err = NULL;
1593 			} else {
1594 				err = got_delta_apply_in_mem(base_buf,
1595 				    base_bufsz, delta_buf, delta_len,
1596 				    accum_buf, &accum_size, max_size);
1597 			}
1598 			n++;
1599 			if (!cached)
1600 				free(delta_buf);
1601 			if (err)
1602 				goto done;
1603 			if (fulltext == NULL) {
1604 				err = got_delta_cache_add_fulltext(
1605 				    pack->delta_cache, delta->data_offset,
1606 				    accum_buf, accum_size);
1607 				if (err) {
1608 					if (err->code != GOT_ERR_NO_SPACE)
1609 						goto done;
1610 					err = NULL;
1611 				}
1612 			}
1613 		} else {
1614 			err = got_delta_apply(base_file, delta_buf,
1615 			    delta_len,
1616 			    /* Final delta application writes to output file. */
1617 			    ++n < deltas->nentries ? accum_file : outfile,
1618 			    &accum_size);
1619 			if (!cached)
1620 				free(delta_buf);
1621 			if (err)
1622 				goto done;
1623 		}
1624 
1625 		if (n < deltas->nentries) {
1626 			/* Accumulated delta becomes the new base. */
1627 			if (base_buf) {
1628 				uint8_t *tmp = accum_buf;
1629 				size_t tmp_size = accum_bufsz;
1630 				accum_buf = base_buf;
1631 				accum_bufsz = base_bufsz;
1632 				base_buf = tmp;
1633 				base_bufsz = tmp_size;
1634 			} else {
1635 				FILE *tmp = accum_file;
1636 				accum_file = base_file;
1637 				base_file = tmp;
1638 				rewind(base_file);
1639 				rewind(accum_file);
1640 			}
1641 		}
1642 	}
1643 
1644 done:
1645 	free(base_buf);
1646 	if (err) {
1647 		free(accum_buf);
1648 		accum_buf = NULL;
1649 	}
1650 	if (accum_buf) {
1651 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1652 		free(accum_buf);
1653 		if (len != accum_size)
1654 			err = got_ferror(outfile, GOT_ERR_IO);
1655 	}
1656 	rewind(outfile);
1657 	if (err == NULL)
1658 		*result_size = accum_size;
1659 	return err;
1660 }
1661 
1662 const struct got_error *
1663 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1664     struct got_delta_chain *deltas, struct got_pack *pack)
1665 {
1666 	const struct got_error *err = NULL;
1667 	struct got_delta *delta;
1668 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1669 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0;
1670 	uint64_t max_size = 0;
1671 	int n = 0;
1672 
1673 	*outbuf = NULL;
1674 	*outlen = 0;
1675 
1676 	if (STAILQ_EMPTY(&deltas->entries))
1677 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1678 
1679 	if (pack->delta_cache) {
1680 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1681 		size_t delta_len, fulltext_len;
1682 
1683 		delta = STAILQ_LAST(&deltas->entries, got_delta, entry);
1684 		got_delta_cache_get(&delta_buf, &delta_len,
1685 		    &fulltext, &fulltext_len,
1686 		    pack->delta_cache, delta->data_offset);
1687 		if (fulltext) {
1688 			*outbuf = malloc(fulltext_len);
1689 			if (*outbuf == NULL)
1690 				return got_error_from_errno("malloc");
1691 			memcpy(*outbuf, fulltext, fulltext_len);
1692 			*outlen = fulltext_len;
1693 			return NULL;
1694 		}
1695 	}
1696 
1697 	/* Deltas are ordered in ascending order. */
1698 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1699 		uint8_t *delta_buf = NULL, *fulltext = NULL;
1700 		size_t delta_len, fulltext_len = 0;
1701 		uint64_t base_size, result_size = 0;
1702 		int cached = 1;
1703 		if (n == 0) {
1704 			off_t delta_data_offset;
1705 
1706 			/* Plain object types are the delta base. */
1707 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1708 			    delta->type != GOT_OBJ_TYPE_TREE &&
1709 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1710 			    delta->type != GOT_OBJ_TYPE_TAG) {
1711 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1712 				goto done;
1713 			}
1714 
1715 			delta_data_offset = delta->offset + delta->tslen;
1716 			if (delta_data_offset >= pack->filesize) {
1717 				err = got_error(GOT_ERR_PACK_OFFSET);
1718 				goto done;
1719 			}
1720 
1721 			if (pack->delta_cache) {
1722 				got_delta_cache_get(&delta_buf, &delta_len,
1723 				    &fulltext, &fulltext_len,
1724 				    pack->delta_cache, delta_data_offset);
1725 			}
1726 
1727 			if (delta->size > max_size)
1728 				max_size = delta->size;
1729 			if (delta->size > fulltext_len)
1730 				max_size = fulltext_len;
1731 
1732 			if (fulltext) {
1733 				base_buf = malloc(fulltext_len);
1734 				if (base_buf == NULL) {
1735 					err = got_error_from_errno("malloc");
1736 					goto done;
1737 				}
1738 				memcpy(base_buf, fulltext, fulltext_len);
1739 				base_bufsz = fulltext_len;
1740 			} else if (pack->map) {
1741 				size_t mapoff;
1742 
1743 				if (delta_data_offset > SIZE_MAX) {
1744 					return got_error_fmt(GOT_ERR_RANGE,
1745 					    "delta %lld offset would "
1746 					    "overflow size_t",
1747 					    (long long)delta_data_offset);
1748 				}
1749 
1750 				mapoff = delta_data_offset;
1751 				err = got_inflate_to_mem_mmap(&base_buf,
1752 				    &base_bufsz, NULL, NULL, pack->map,
1753 				    mapoff, pack->filesize - mapoff);
1754 			} else {
1755 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1756 				    == -1) {
1757 					err = got_error_from_errno("lseek");
1758 					goto done;
1759 				}
1760 				err = got_inflate_to_mem_fd(&base_buf,
1761 				    &base_bufsz, NULL, NULL, max_size,
1762 				    pack->fd);
1763 			}
1764 			if (err)
1765 				goto done;
1766 			n++;
1767 
1768 			if (pack->delta_cache && fulltext == NULL) {
1769 				err = got_delta_cache_add(pack->delta_cache,
1770 				    delta_data_offset, NULL, 0);
1771 				if (err) {
1772 					if (err->code != GOT_ERR_NO_SPACE)
1773 						goto done;
1774 					err = NULL;
1775 				} else {
1776 					err = got_delta_cache_add_fulltext(
1777 					    pack->delta_cache,
1778 					    delta_data_offset,
1779 					    base_buf, base_bufsz);
1780 					if (err &&
1781 					    err->code != GOT_ERR_NO_SPACE)
1782 						goto done;
1783 					err = NULL;
1784 				}
1785 			}
1786 			continue;
1787 		}
1788 
1789 		if (pack->delta_cache) {
1790 			got_delta_cache_get(&delta_buf, &delta_len,
1791 			    &fulltext, &fulltext_len,
1792 			    pack->delta_cache, delta->data_offset);
1793 		}
1794 		if (delta_buf == NULL) {
1795 			cached = 0;
1796 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1797 			    delta->data_offset, pack);
1798 			if (err)
1799 				goto done;
1800 		}
1801 		if (pack->delta_cache && !cached) {
1802 			err = got_delta_cache_add(pack->delta_cache,
1803 			    delta->data_offset, delta_buf, delta_len);
1804 			if (err == NULL)
1805 				cached = 1;
1806 			else if (err->code != GOT_ERR_NO_SPACE) {
1807 				free(delta_buf);
1808 				goto done;
1809 			}
1810 		}
1811 
1812 		err = got_delta_get_sizes(&base_size, &result_size,
1813 		    delta_buf, delta_len);
1814 		if (err) {
1815 			if (!cached)
1816 				free(delta_buf);
1817 			goto done;
1818 		}
1819 		if (base_size > max_size)
1820 			max_size = base_size;
1821 		if (result_size > max_size)
1822 			max_size = result_size;
1823 		if (fulltext_len > max_size)
1824 			max_size = fulltext_len;
1825 
1826 		if (max_size > base_bufsz) {
1827 			uint8_t *p = realloc(base_buf, max_size);
1828 			if (p == NULL) {
1829 				err = got_error_from_errno("realloc");
1830 				if (!cached)
1831 					free(delta_buf);
1832 				goto done;
1833 			}
1834 			base_buf = p;
1835 			base_bufsz = max_size;
1836 		}
1837 
1838 		if (max_size > accum_bufsz) {
1839 			uint8_t *p = realloc(accum_buf, max_size);
1840 			if (p == NULL) {
1841 				err = got_error_from_errno("realloc");
1842 				if (!cached)
1843 					free(delta_buf);
1844 				goto done;
1845 			}
1846 			accum_buf = p;
1847 			accum_bufsz = max_size;
1848 		}
1849 
1850 		if (fulltext) {
1851 			memcpy(accum_buf, fulltext, fulltext_len);
1852 			accum_size = fulltext_len;
1853 			err = NULL;
1854 		} else {
1855 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1856 			    delta_buf, delta_len, accum_buf,
1857 			    &accum_size, max_size);
1858 		}
1859 		if (!cached)
1860 			free(delta_buf);
1861 		n++;
1862 		if (err)
1863 			goto done;
1864 
1865 		if (fulltext == NULL) {
1866 			err = got_delta_cache_add_fulltext(pack->delta_cache,
1867 			    delta->data_offset, accum_buf, accum_size);
1868 			if (err) {
1869 				if (err->code != GOT_ERR_NO_SPACE)
1870 					goto done;
1871 				err = NULL;
1872 			}
1873 		}
1874 
1875 		if (n < deltas->nentries) {
1876 			/* Accumulated delta becomes the new base. */
1877 			uint8_t *tmp = accum_buf;
1878 			size_t tmp_size = accum_bufsz;
1879 			accum_buf = base_buf;
1880 			accum_bufsz = base_bufsz;
1881 			base_buf = tmp;
1882 			base_bufsz = tmp_size;
1883 		}
1884 	}
1885 
1886 done:
1887 	free(base_buf);
1888 	if (err) {
1889 		free(accum_buf);
1890 		*outbuf = NULL;
1891 		*outlen = 0;
1892 	} else {
1893 		*outbuf = accum_buf;
1894 		*outlen = accum_size;
1895 	}
1896 	return err;
1897 }
1898 
1899 const struct got_error *
1900 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1901     FILE *outfile, FILE *base_file, FILE *accum_file)
1902 {
1903 	const struct got_error *err = NULL;
1904 
1905 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1906 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1907 
1908 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1909 		if (obj->pack_offset >= pack->filesize)
1910 			return got_error(GOT_ERR_PACK_OFFSET);
1911 
1912 		if (pack->map) {
1913 			size_t mapoff;
1914 
1915 			if (obj->pack_offset > SIZE_MAX) {
1916 				return got_error_fmt(GOT_ERR_RANGE,
1917 				    "pack offset %lld would overflow size_t",
1918 				    (long long)obj->pack_offset);
1919 			}
1920 
1921 			mapoff = obj->pack_offset;
1922 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1923 			    pack->map, mapoff, pack->filesize - mapoff,
1924 			    outfile);
1925 		} else {
1926 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1927 				return got_error_from_errno("lseek");
1928 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1929 			    pack->fd, outfile);
1930 		}
1931 	} else
1932 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1933 		    &obj->deltas, pack, outfile, base_file, accum_file);
1934 
1935 	return err;
1936 }
1937 
1938 const struct got_error *
1939 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1940     struct got_object *obj, struct got_pack *pack)
1941 {
1942 	const struct got_error *err = NULL;
1943 
1944 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1945 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1946 
1947 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1948 		if (obj->pack_offset >= pack->filesize)
1949 			return got_error(GOT_ERR_PACK_OFFSET);
1950 		if (pack->map) {
1951 			size_t mapoff;
1952 
1953 			if (obj->pack_offset > SIZE_MAX) {
1954 				return got_error_fmt(GOT_ERR_RANGE,
1955 				    "pack offset %lld would overflow size_t",
1956 				    (long long)obj->pack_offset);
1957 			}
1958 
1959 			mapoff = obj->pack_offset;
1960 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1961 			    pack->map, mapoff, pack->filesize - mapoff);
1962 		} else {
1963 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1964 				return got_error_from_errno("lseek");
1965 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1966 			    obj->size, pack->fd);
1967 		}
1968 	} else
1969 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1970 		    pack);
1971 
1972 	return err;
1973 }
1974 
1975 static const struct got_error *
1976 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1977     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1978     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1979 {
1980 	const struct got_error *err = NULL;
1981 
1982 	/* Validate decompression and obtain the decompressed size. */
1983 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1984 	    delta_data_offset, pack);
1985 	if (err)
1986 		return err;
1987 
1988 	/* Read delta base/result sizes from head of delta stream. */
1989 	err = got_delta_get_sizes(base_size, result_size,
1990 	    *delta_buf, *delta_len);
1991 	if (err)
1992 		goto done;
1993 
1994 	/* Discard decompressed delta and read it again in compressed form. */
1995 	free(*delta_buf);
1996 	*delta_buf = malloc(*delta_len_compressed);
1997 	if (*delta_buf == NULL) {
1998 		err = got_error_from_errno("malloc");
1999 		goto done;
2000 	}
2001 	if (pack->map) {
2002 		if (delta_data_offset >= pack->filesize) {
2003 			err = got_error(GOT_ERR_PACK_OFFSET);
2004 			goto done;
2005 		}
2006 		memcpy(*delta_buf, pack->map + delta_data_offset,
2007 		    *delta_len_compressed);
2008 	} else {
2009 		ssize_t n;
2010 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
2011 			err = got_error_from_errno("lseek");
2012 			goto done;
2013 		}
2014 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
2015 		if (n < 0) {
2016 			err = got_error_from_errno("read");
2017 			goto done;
2018 		} else if (n != *delta_len_compressed) {
2019 			err = got_error(GOT_ERR_IO);
2020 			goto done;
2021 		}
2022 	}
2023 done:
2024 	if (err) {
2025 		free(*delta_buf);
2026 		*delta_buf = NULL;
2027 		*delta_len = 0;
2028 		*delta_len_compressed = 0;
2029 		*base_size = 0;
2030 		*result_size = 0;
2031 	}
2032 	return err;
2033 }
2034 
2035 const struct got_error *
2036 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
2037     size_t *delta_compressed_size, off_t *delta_offset,
2038     off_t *delta_data_offset, off_t *base_offset,
2039     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
2040     struct got_pack *pack, struct got_packidx *packidx, int idx)
2041 {
2042 	const struct got_error *err = NULL;
2043 	off_t offset;
2044 	uint8_t type;
2045 	uint64_t size;
2046 	size_t tslen, delta_hdrlen;
2047 
2048 	*delta_buf = NULL;
2049 	*delta_size = 0;
2050 	*delta_compressed_size = 0;
2051 	*delta_offset = 0;
2052 	*delta_data_offset = 0;
2053 	*base_offset = 0;
2054 	*base_size = 0;
2055 	*result_size = 0;
2056 
2057 	offset = got_packidx_get_object_offset(packidx, idx);
2058 	if (offset == -1)
2059 		return got_error(GOT_ERR_BAD_PACKIDX);
2060 
2061 	if (offset >= pack->filesize)
2062 		return got_error(GOT_ERR_PACK_OFFSET);
2063 
2064 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
2065 	    pack, offset);
2066 	if (err)
2067 		return err;
2068 
2069 	if (tslen + size < tslen || offset + size < size ||
2070 	    tslen + offset < tslen)
2071 		return got_error(GOT_ERR_PACK_OFFSET);
2072 
2073 	switch (type) {
2074 	case GOT_OBJ_TYPE_OFFSET_DELTA:
2075 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
2076 		    pack, offset, tslen);
2077 		if (err)
2078 			return err;
2079 		break;
2080 	case GOT_OBJ_TYPE_REF_DELTA:
2081 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
2082 		if (err)
2083 			return err;
2084 		delta_hdrlen = SHA1_DIGEST_LENGTH;
2085 		break;
2086 	default:
2087 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
2088 		    "non-delta object type %d found at offset %lld",
2089 		    type, (long long)offset);
2090 	}
2091 
2092 	if (tslen + delta_hdrlen < delta_hdrlen ||
2093 	    offset + delta_hdrlen < delta_hdrlen)
2094 		return got_error(GOT_ERR_BAD_DELTA);
2095 
2096 	*delta_data_offset = offset + tslen + delta_hdrlen;
2097 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
2098 	    base_size, result_size, *delta_data_offset, pack, packidx);
2099 	if (err)
2100 		return err;
2101 
2102 	if (*delta_size != size) {
2103 		err = got_error(GOT_ERR_BAD_DELTA);
2104 		goto done;
2105 	}
2106 
2107 	*delta_offset = offset;
2108 done:
2109 	if (err) {
2110 		free(*delta_buf);
2111 		*delta_buf = NULL;
2112 		*delta_size = 0;
2113 		*delta_compressed_size = 0;
2114 		*delta_offset = 0;
2115 		*base_offset = 0;
2116 		*base_size = 0;
2117 		*result_size = 0;
2118 	}
2119 	return err;
2120 }